diff.con commit Merge branch 'tb/blame-force-read-cache-to-workaround-safe-crlf' (6680016)
   1/*
   2 * Copyright (C) 2005 Junio C Hamano
   3 */
   4#include "cache.h"
   5#include "tempfile.h"
   6#include "quote.h"
   7#include "diff.h"
   8#include "diffcore.h"
   9#include "delta.h"
  10#include "xdiff-interface.h"
  11#include "color.h"
  12#include "attr.h"
  13#include "run-command.h"
  14#include "utf8.h"
  15#include "userdiff.h"
  16#include "submodule-config.h"
  17#include "submodule.h"
  18#include "ll-merge.h"
  19#include "string-list.h"
  20#include "argv-array.h"
  21
  22#ifdef NO_FAST_WORKING_DIRECTORY
  23#define FAST_WORKING_DIRECTORY 0
  24#else
  25#define FAST_WORKING_DIRECTORY 1
  26#endif
  27
  28static int diff_detect_rename_default;
  29static int diff_rename_limit_default = 400;
  30static int diff_suppress_blank_empty;
  31static int diff_use_color_default = -1;
  32static int diff_context_default = 3;
  33static const char *diff_word_regex_cfg;
  34static const char *external_diff_cmd_cfg;
  35static const char *diff_order_file_cfg;
  36int diff_auto_refresh_index = 1;
  37static int diff_mnemonic_prefix;
  38static int diff_no_prefix;
  39static int diff_stat_graph_width;
  40static int diff_dirstat_permille_default = 30;
  41static struct diff_options default_diff_options;
  42static long diff_algorithm;
  43
  44static char diff_colors[][COLOR_MAXLEN] = {
  45        GIT_COLOR_RESET,
  46        GIT_COLOR_NORMAL,       /* CONTEXT */
  47        GIT_COLOR_BOLD,         /* METAINFO */
  48        GIT_COLOR_CYAN,         /* FRAGINFO */
  49        GIT_COLOR_RED,          /* OLD */
  50        GIT_COLOR_GREEN,        /* NEW */
  51        GIT_COLOR_YELLOW,       /* COMMIT */
  52        GIT_COLOR_BG_RED,       /* WHITESPACE */
  53        GIT_COLOR_NORMAL,       /* FUNCINFO */
  54};
  55
  56static int parse_diff_color_slot(const char *var)
  57{
  58        if (!strcasecmp(var, "context") || !strcasecmp(var, "plain"))
  59                return DIFF_CONTEXT;
  60        if (!strcasecmp(var, "meta"))
  61                return DIFF_METAINFO;
  62        if (!strcasecmp(var, "frag"))
  63                return DIFF_FRAGINFO;
  64        if (!strcasecmp(var, "old"))
  65                return DIFF_FILE_OLD;
  66        if (!strcasecmp(var, "new"))
  67                return DIFF_FILE_NEW;
  68        if (!strcasecmp(var, "commit"))
  69                return DIFF_COMMIT;
  70        if (!strcasecmp(var, "whitespace"))
  71                return DIFF_WHITESPACE;
  72        if (!strcasecmp(var, "func"))
  73                return DIFF_FUNCINFO;
  74        return -1;
  75}
  76
  77static int parse_dirstat_params(struct diff_options *options, const char *params_string,
  78                                struct strbuf *errmsg)
  79{
  80        char *params_copy = xstrdup(params_string);
  81        struct string_list params = STRING_LIST_INIT_NODUP;
  82        int ret = 0;
  83        int i;
  84
  85        if (*params_copy)
  86                string_list_split_in_place(&params, params_copy, ',', -1);
  87        for (i = 0; i < params.nr; i++) {
  88                const char *p = params.items[i].string;
  89                if (!strcmp(p, "changes")) {
  90                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  91                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  92                } else if (!strcmp(p, "lines")) {
  93                        DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
  94                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  95                } else if (!strcmp(p, "files")) {
  96                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  97                        DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
  98                } else if (!strcmp(p, "noncumulative")) {
  99                        DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
 100                } else if (!strcmp(p, "cumulative")) {
 101                        DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
 102                } else if (isdigit(*p)) {
 103                        char *end;
 104                        int permille = strtoul(p, &end, 10) * 10;
 105                        if (*end == '.' && isdigit(*++end)) {
 106                                /* only use first digit */
 107                                permille += *end - '0';
 108                                /* .. and ignore any further digits */
 109                                while (isdigit(*++end))
 110                                        ; /* nothing */
 111                        }
 112                        if (!*end)
 113                                options->dirstat_permille = permille;
 114                        else {
 115                                strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 116                                            p);
 117                                ret++;
 118                        }
 119                } else {
 120                        strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 121                        ret++;
 122                }
 123
 124        }
 125        string_list_clear(&params, 0);
 126        free(params_copy);
 127        return ret;
 128}
 129
 130static int parse_submodule_params(struct diff_options *options, const char *value)
 131{
 132        if (!strcmp(value, "log"))
 133                DIFF_OPT_SET(options, SUBMODULE_LOG);
 134        else if (!strcmp(value, "short"))
 135                DIFF_OPT_CLR(options, SUBMODULE_LOG);
 136        else
 137                return -1;
 138        return 0;
 139}
 140
 141static int git_config_rename(const char *var, const char *value)
 142{
 143        if (!value)
 144                return DIFF_DETECT_RENAME;
 145        if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 146                return  DIFF_DETECT_COPY;
 147        return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 148}
 149
 150long parse_algorithm_value(const char *value)
 151{
 152        if (!value)
 153                return -1;
 154        else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 155                return 0;
 156        else if (!strcasecmp(value, "minimal"))
 157                return XDF_NEED_MINIMAL;
 158        else if (!strcasecmp(value, "patience"))
 159                return XDF_PATIENCE_DIFF;
 160        else if (!strcasecmp(value, "histogram"))
 161                return XDF_HISTOGRAM_DIFF;
 162        return -1;
 163}
 164
 165/*
 166 * These are to give UI layer defaults.
 167 * The core-level commands such as git-diff-files should
 168 * never be affected by the setting of diff.renames
 169 * the user happens to have in the configuration file.
 170 */
 171void init_diff_ui_defaults(void)
 172{
 173        diff_detect_rename_default = 1;
 174}
 175
 176int git_diff_ui_config(const char *var, const char *value, void *cb)
 177{
 178        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 179                diff_use_color_default = git_config_colorbool(var, value);
 180                return 0;
 181        }
 182        if (!strcmp(var, "diff.context")) {
 183                diff_context_default = git_config_int(var, value);
 184                if (diff_context_default < 0)
 185                        return -1;
 186                return 0;
 187        }
 188        if (!strcmp(var, "diff.renames")) {
 189                diff_detect_rename_default = git_config_rename(var, value);
 190                return 0;
 191        }
 192        if (!strcmp(var, "diff.autorefreshindex")) {
 193                diff_auto_refresh_index = git_config_bool(var, value);
 194                return 0;
 195        }
 196        if (!strcmp(var, "diff.mnemonicprefix")) {
 197                diff_mnemonic_prefix = git_config_bool(var, value);
 198                return 0;
 199        }
 200        if (!strcmp(var, "diff.noprefix")) {
 201                diff_no_prefix = git_config_bool(var, value);
 202                return 0;
 203        }
 204        if (!strcmp(var, "diff.statgraphwidth")) {
 205                diff_stat_graph_width = git_config_int(var, value);
 206                return 0;
 207        }
 208        if (!strcmp(var, "diff.external"))
 209                return git_config_string(&external_diff_cmd_cfg, var, value);
 210        if (!strcmp(var, "diff.wordregex"))
 211                return git_config_string(&diff_word_regex_cfg, var, value);
 212        if (!strcmp(var, "diff.orderfile"))
 213                return git_config_pathname(&diff_order_file_cfg, var, value);
 214
 215        if (!strcmp(var, "diff.ignoresubmodules"))
 216                handle_ignore_submodules_arg(&default_diff_options, value);
 217
 218        if (!strcmp(var, "diff.submodule")) {
 219                if (parse_submodule_params(&default_diff_options, value))
 220                        warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 221                                value);
 222                return 0;
 223        }
 224
 225        if (!strcmp(var, "diff.algorithm")) {
 226                diff_algorithm = parse_algorithm_value(value);
 227                if (diff_algorithm < 0)
 228                        return -1;
 229                return 0;
 230        }
 231
 232        if (git_color_config(var, value, cb) < 0)
 233                return -1;
 234
 235        return git_diff_basic_config(var, value, cb);
 236}
 237
 238int git_diff_basic_config(const char *var, const char *value, void *cb)
 239{
 240        const char *name;
 241
 242        if (!strcmp(var, "diff.renamelimit")) {
 243                diff_rename_limit_default = git_config_int(var, value);
 244                return 0;
 245        }
 246
 247        if (userdiff_config(var, value) < 0)
 248                return -1;
 249
 250        if (skip_prefix(var, "diff.color.", &name) ||
 251            skip_prefix(var, "color.diff.", &name)) {
 252                int slot = parse_diff_color_slot(name);
 253                if (slot < 0)
 254                        return 0;
 255                if (!value)
 256                        return config_error_nonbool(var);
 257                return color_parse(value, diff_colors[slot]);
 258        }
 259
 260        /* like GNU diff's --suppress-blank-empty option  */
 261        if (!strcmp(var, "diff.suppressblankempty") ||
 262                        /* for backwards compatibility */
 263                        !strcmp(var, "diff.suppress-blank-empty")) {
 264                diff_suppress_blank_empty = git_config_bool(var, value);
 265                return 0;
 266        }
 267
 268        if (!strcmp(var, "diff.dirstat")) {
 269                struct strbuf errmsg = STRBUF_INIT;
 270                default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 271                if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 272                        warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 273                                errmsg.buf);
 274                strbuf_release(&errmsg);
 275                diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 276                return 0;
 277        }
 278
 279        if (starts_with(var, "submodule."))
 280                return parse_submodule_config_option(var, value);
 281
 282        return git_default_config(var, value, cb);
 283}
 284
 285static char *quote_two(const char *one, const char *two)
 286{
 287        int need_one = quote_c_style(one, NULL, NULL, 1);
 288        int need_two = quote_c_style(two, NULL, NULL, 1);
 289        struct strbuf res = STRBUF_INIT;
 290
 291        if (need_one + need_two) {
 292                strbuf_addch(&res, '"');
 293                quote_c_style(one, &res, NULL, 1);
 294                quote_c_style(two, &res, NULL, 1);
 295                strbuf_addch(&res, '"');
 296        } else {
 297                strbuf_addstr(&res, one);
 298                strbuf_addstr(&res, two);
 299        }
 300        return strbuf_detach(&res, NULL);
 301}
 302
 303static const char *external_diff(void)
 304{
 305        static const char *external_diff_cmd = NULL;
 306        static int done_preparing = 0;
 307
 308        if (done_preparing)
 309                return external_diff_cmd;
 310        external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 311        if (!external_diff_cmd)
 312                external_diff_cmd = external_diff_cmd_cfg;
 313        done_preparing = 1;
 314        return external_diff_cmd;
 315}
 316
 317/*
 318 * Keep track of files used for diffing. Sometimes such an entry
 319 * refers to a temporary file, sometimes to an existing file, and
 320 * sometimes to "/dev/null".
 321 */
 322static struct diff_tempfile {
 323        /*
 324         * filename external diff should read from, or NULL if this
 325         * entry is currently not in use:
 326         */
 327        const char *name;
 328
 329        char hex[GIT_SHA1_HEXSZ + 1];
 330        char mode[10];
 331
 332        /*
 333         * If this diff_tempfile instance refers to a temporary file,
 334         * this tempfile object is used to manage its lifetime.
 335         */
 336        struct tempfile tempfile;
 337} diff_temp[2];
 338
 339typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 340
 341struct emit_callback {
 342        int color_diff;
 343        unsigned ws_rule;
 344        int blank_at_eof_in_preimage;
 345        int blank_at_eof_in_postimage;
 346        int lno_in_preimage;
 347        int lno_in_postimage;
 348        sane_truncate_fn truncate;
 349        const char **label_path;
 350        struct diff_words_data *diff_words;
 351        struct diff_options *opt;
 352        int *found_changesp;
 353        struct strbuf *header;
 354};
 355
 356static int count_lines(const char *data, int size)
 357{
 358        int count, ch, completely_empty = 1, nl_just_seen = 0;
 359        count = 0;
 360        while (0 < size--) {
 361                ch = *data++;
 362                if (ch == '\n') {
 363                        count++;
 364                        nl_just_seen = 1;
 365                        completely_empty = 0;
 366                }
 367                else {
 368                        nl_just_seen = 0;
 369                        completely_empty = 0;
 370                }
 371        }
 372        if (completely_empty)
 373                return 0;
 374        if (!nl_just_seen)
 375                count++; /* no trailing newline */
 376        return count;
 377}
 378
 379static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 380{
 381        if (!DIFF_FILE_VALID(one)) {
 382                mf->ptr = (char *)""; /* does not matter */
 383                mf->size = 0;
 384                return 0;
 385        }
 386        else if (diff_populate_filespec(one, 0))
 387                return -1;
 388
 389        mf->ptr = one->data;
 390        mf->size = one->size;
 391        return 0;
 392}
 393
 394/* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 395static unsigned long diff_filespec_size(struct diff_filespec *one)
 396{
 397        if (!DIFF_FILE_VALID(one))
 398                return 0;
 399        diff_populate_filespec(one, CHECK_SIZE_ONLY);
 400        return one->size;
 401}
 402
 403static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 404{
 405        char *ptr = mf->ptr;
 406        long size = mf->size;
 407        int cnt = 0;
 408
 409        if (!size)
 410                return cnt;
 411        ptr += size - 1; /* pointing at the very end */
 412        if (*ptr != '\n')
 413                ; /* incomplete line */
 414        else
 415                ptr--; /* skip the last LF */
 416        while (mf->ptr < ptr) {
 417                char *prev_eol;
 418                for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 419                        if (*prev_eol == '\n')
 420                                break;
 421                if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 422                        break;
 423                cnt++;
 424                ptr = prev_eol - 1;
 425        }
 426        return cnt;
 427}
 428
 429static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 430                               struct emit_callback *ecbdata)
 431{
 432        int l1, l2, at;
 433        unsigned ws_rule = ecbdata->ws_rule;
 434        l1 = count_trailing_blank(mf1, ws_rule);
 435        l2 = count_trailing_blank(mf2, ws_rule);
 436        if (l2 <= l1) {
 437                ecbdata->blank_at_eof_in_preimage = 0;
 438                ecbdata->blank_at_eof_in_postimage = 0;
 439                return;
 440        }
 441        at = count_lines(mf1->ptr, mf1->size);
 442        ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 443
 444        at = count_lines(mf2->ptr, mf2->size);
 445        ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 446}
 447
 448static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 449                        int first, const char *line, int len)
 450{
 451        int has_trailing_newline, has_trailing_carriage_return;
 452        int nofirst;
 453        FILE *file = o->file;
 454
 455        fputs(diff_line_prefix(o), file);
 456
 457        if (len == 0) {
 458                has_trailing_newline = (first == '\n');
 459                has_trailing_carriage_return = (!has_trailing_newline &&
 460                                                (first == '\r'));
 461                nofirst = has_trailing_newline || has_trailing_carriage_return;
 462        } else {
 463                has_trailing_newline = (len > 0 && line[len-1] == '\n');
 464                if (has_trailing_newline)
 465                        len--;
 466                has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 467                if (has_trailing_carriage_return)
 468                        len--;
 469                nofirst = 0;
 470        }
 471
 472        if (len || !nofirst) {
 473                fputs(set, file);
 474                if (!nofirst)
 475                        fputc(first, file);
 476                fwrite(line, len, 1, file);
 477                fputs(reset, file);
 478        }
 479        if (has_trailing_carriage_return)
 480                fputc('\r', file);
 481        if (has_trailing_newline)
 482                fputc('\n', file);
 483}
 484
 485static void emit_line(struct diff_options *o, const char *set, const char *reset,
 486                      const char *line, int len)
 487{
 488        emit_line_0(o, set, reset, line[0], line+1, len-1);
 489}
 490
 491static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 492{
 493        if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 494              ecbdata->blank_at_eof_in_preimage &&
 495              ecbdata->blank_at_eof_in_postimage &&
 496              ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 497              ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 498                return 0;
 499        return ws_blank_line(line, len, ecbdata->ws_rule);
 500}
 501
 502static void emit_line_checked(const char *reset,
 503                              struct emit_callback *ecbdata,
 504                              const char *line, int len,
 505                              enum color_diff color,
 506                              unsigned ws_error_highlight,
 507                              char sign)
 508{
 509        const char *set = diff_get_color(ecbdata->color_diff, color);
 510        const char *ws = NULL;
 511
 512        if (ecbdata->opt->ws_error_highlight & ws_error_highlight) {
 513                ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 514                if (!*ws)
 515                        ws = NULL;
 516        }
 517
 518        if (!ws)
 519                emit_line_0(ecbdata->opt, set, reset, sign, line, len);
 520        else if (sign == '+' && new_blank_line_at_eof(ecbdata, line, len))
 521                /* Blank line at EOF - paint '+' as well */
 522                emit_line_0(ecbdata->opt, ws, reset, sign, line, len);
 523        else {
 524                /* Emit just the prefix, then the rest. */
 525                emit_line_0(ecbdata->opt, set, reset, sign, "", 0);
 526                ws_check_emit(line, len, ecbdata->ws_rule,
 527                              ecbdata->opt->file, set, reset, ws);
 528        }
 529}
 530
 531static void emit_add_line(const char *reset,
 532                          struct emit_callback *ecbdata,
 533                          const char *line, int len)
 534{
 535        emit_line_checked(reset, ecbdata, line, len,
 536                          DIFF_FILE_NEW, WSEH_NEW, '+');
 537}
 538
 539static void emit_del_line(const char *reset,
 540                          struct emit_callback *ecbdata,
 541                          const char *line, int len)
 542{
 543        emit_line_checked(reset, ecbdata, line, len,
 544                          DIFF_FILE_OLD, WSEH_OLD, '-');
 545}
 546
 547static void emit_context_line(const char *reset,
 548                              struct emit_callback *ecbdata,
 549                              const char *line, int len)
 550{
 551        emit_line_checked(reset, ecbdata, line, len,
 552                          DIFF_CONTEXT, WSEH_CONTEXT, ' ');
 553}
 554
 555static void emit_hunk_header(struct emit_callback *ecbdata,
 556                             const char *line, int len)
 557{
 558        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
 559        const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 560        const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 561        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 562        static const char atat[2] = { '@', '@' };
 563        const char *cp, *ep;
 564        struct strbuf msgbuf = STRBUF_INIT;
 565        int org_len = len;
 566        int i = 1;
 567
 568        /*
 569         * As a hunk header must begin with "@@ -<old>, +<new> @@",
 570         * it always is at least 10 bytes long.
 571         */
 572        if (len < 10 ||
 573            memcmp(line, atat, 2) ||
 574            !(ep = memmem(line + 2, len - 2, atat, 2))) {
 575                emit_line(ecbdata->opt, context, reset, line, len);
 576                return;
 577        }
 578        ep += 2; /* skip over @@ */
 579
 580        /* The hunk header in fraginfo color */
 581        strbuf_addstr(&msgbuf, frag);
 582        strbuf_add(&msgbuf, line, ep - line);
 583        strbuf_addstr(&msgbuf, reset);
 584
 585        /*
 586         * trailing "\r\n"
 587         */
 588        for ( ; i < 3; i++)
 589                if (line[len - i] == '\r' || line[len - i] == '\n')
 590                        len--;
 591
 592        /* blank before the func header */
 593        for (cp = ep; ep - line < len; ep++)
 594                if (*ep != ' ' && *ep != '\t')
 595                        break;
 596        if (ep != cp) {
 597                strbuf_addstr(&msgbuf, context);
 598                strbuf_add(&msgbuf, cp, ep - cp);
 599                strbuf_addstr(&msgbuf, reset);
 600        }
 601
 602        if (ep < line + len) {
 603                strbuf_addstr(&msgbuf, func);
 604                strbuf_add(&msgbuf, ep, line + len - ep);
 605                strbuf_addstr(&msgbuf, reset);
 606        }
 607
 608        strbuf_add(&msgbuf, line + len, org_len - len);
 609        emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 610        strbuf_release(&msgbuf);
 611}
 612
 613static struct diff_tempfile *claim_diff_tempfile(void) {
 614        int i;
 615        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 616                if (!diff_temp[i].name)
 617                        return diff_temp + i;
 618        die("BUG: diff is failing to clean up its tempfiles");
 619}
 620
 621static void remove_tempfile(void)
 622{
 623        int i;
 624        for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 625                if (is_tempfile_active(&diff_temp[i].tempfile))
 626                        delete_tempfile(&diff_temp[i].tempfile);
 627                diff_temp[i].name = NULL;
 628        }
 629}
 630
 631static void print_line_count(FILE *file, int count)
 632{
 633        switch (count) {
 634        case 0:
 635                fprintf(file, "0,0");
 636                break;
 637        case 1:
 638                fprintf(file, "1");
 639                break;
 640        default:
 641                fprintf(file, "1,%d", count);
 642                break;
 643        }
 644}
 645
 646static void emit_rewrite_lines(struct emit_callback *ecb,
 647                               int prefix, const char *data, int size)
 648{
 649        const char *endp = NULL;
 650        static const char *nneof = " No newline at end of file\n";
 651        const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 652
 653        while (0 < size) {
 654                int len;
 655
 656                endp = memchr(data, '\n', size);
 657                len = endp ? (endp - data + 1) : size;
 658                if (prefix != '+') {
 659                        ecb->lno_in_preimage++;
 660                        emit_del_line(reset, ecb, data, len);
 661                } else {
 662                        ecb->lno_in_postimage++;
 663                        emit_add_line(reset, ecb, data, len);
 664                }
 665                size -= len;
 666                data += len;
 667        }
 668        if (!endp) {
 669                const char *context = diff_get_color(ecb->color_diff,
 670                                                     DIFF_CONTEXT);
 671                putc('\n', ecb->opt->file);
 672                emit_line_0(ecb->opt, context, reset, '\\',
 673                            nneof, strlen(nneof));
 674        }
 675}
 676
 677static void emit_rewrite_diff(const char *name_a,
 678                              const char *name_b,
 679                              struct diff_filespec *one,
 680                              struct diff_filespec *two,
 681                              struct userdiff_driver *textconv_one,
 682                              struct userdiff_driver *textconv_two,
 683                              struct diff_options *o)
 684{
 685        int lc_a, lc_b;
 686        const char *name_a_tab, *name_b_tab;
 687        const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 688        const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 689        const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 690        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 691        const char *a_prefix, *b_prefix;
 692        char *data_one, *data_two;
 693        size_t size_one, size_two;
 694        struct emit_callback ecbdata;
 695        const char *line_prefix = diff_line_prefix(o);
 696
 697        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 698                a_prefix = o->b_prefix;
 699                b_prefix = o->a_prefix;
 700        } else {
 701                a_prefix = o->a_prefix;
 702                b_prefix = o->b_prefix;
 703        }
 704
 705        name_a += (*name_a == '/');
 706        name_b += (*name_b == '/');
 707        name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 708        name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 709
 710        strbuf_reset(&a_name);
 711        strbuf_reset(&b_name);
 712        quote_two_c_style(&a_name, a_prefix, name_a, 0);
 713        quote_two_c_style(&b_name, b_prefix, name_b, 0);
 714
 715        size_one = fill_textconv(textconv_one, one, &data_one);
 716        size_two = fill_textconv(textconv_two, two, &data_two);
 717
 718        memset(&ecbdata, 0, sizeof(ecbdata));
 719        ecbdata.color_diff = want_color(o->use_color);
 720        ecbdata.found_changesp = &o->found_changes;
 721        ecbdata.ws_rule = whitespace_rule(name_b);
 722        ecbdata.opt = o;
 723        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 724                mmfile_t mf1, mf2;
 725                mf1.ptr = (char *)data_one;
 726                mf2.ptr = (char *)data_two;
 727                mf1.size = size_one;
 728                mf2.size = size_two;
 729                check_blank_at_eof(&mf1, &mf2, &ecbdata);
 730        }
 731        ecbdata.lno_in_preimage = 1;
 732        ecbdata.lno_in_postimage = 1;
 733
 734        lc_a = count_lines(data_one, size_one);
 735        lc_b = count_lines(data_two, size_two);
 736        fprintf(o->file,
 737                "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 738                line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 739                line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 740                line_prefix, fraginfo);
 741        if (!o->irreversible_delete)
 742                print_line_count(o->file, lc_a);
 743        else
 744                fprintf(o->file, "?,?");
 745        fprintf(o->file, " +");
 746        print_line_count(o->file, lc_b);
 747        fprintf(o->file, " @@%s\n", reset);
 748        if (lc_a && !o->irreversible_delete)
 749                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 750        if (lc_b)
 751                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 752        if (textconv_one)
 753                free((char *)data_one);
 754        if (textconv_two)
 755                free((char *)data_two);
 756}
 757
 758struct diff_words_buffer {
 759        mmfile_t text;
 760        long alloc;
 761        struct diff_words_orig {
 762                const char *begin, *end;
 763        } *orig;
 764        int orig_nr, orig_alloc;
 765};
 766
 767static void diff_words_append(char *line, unsigned long len,
 768                struct diff_words_buffer *buffer)
 769{
 770        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 771        line++;
 772        len--;
 773        memcpy(buffer->text.ptr + buffer->text.size, line, len);
 774        buffer->text.size += len;
 775        buffer->text.ptr[buffer->text.size] = '\0';
 776}
 777
 778struct diff_words_style_elem {
 779        const char *prefix;
 780        const char *suffix;
 781        const char *color; /* NULL; filled in by the setup code if
 782                            * color is enabled */
 783};
 784
 785struct diff_words_style {
 786        enum diff_words_type type;
 787        struct diff_words_style_elem new, old, ctx;
 788        const char *newline;
 789};
 790
 791static struct diff_words_style diff_words_styles[] = {
 792        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 793        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 794        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 795};
 796
 797struct diff_words_data {
 798        struct diff_words_buffer minus, plus;
 799        const char *current_plus;
 800        int last_minus;
 801        struct diff_options *opt;
 802        regex_t *word_regex;
 803        enum diff_words_type type;
 804        struct diff_words_style *style;
 805};
 806
 807static int fn_out_diff_words_write_helper(FILE *fp,
 808                                          struct diff_words_style_elem *st_el,
 809                                          const char *newline,
 810                                          size_t count, const char *buf,
 811                                          const char *line_prefix)
 812{
 813        int print = 0;
 814
 815        while (count) {
 816                char *p = memchr(buf, '\n', count);
 817                if (print)
 818                        fputs(line_prefix, fp);
 819                if (p != buf) {
 820                        if (st_el->color && fputs(st_el->color, fp) < 0)
 821                                return -1;
 822                        if (fputs(st_el->prefix, fp) < 0 ||
 823                            fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 824                            fputs(st_el->suffix, fp) < 0)
 825                                return -1;
 826                        if (st_el->color && *st_el->color
 827                            && fputs(GIT_COLOR_RESET, fp) < 0)
 828                                return -1;
 829                }
 830                if (!p)
 831                        return 0;
 832                if (fputs(newline, fp) < 0)
 833                        return -1;
 834                count -= p + 1 - buf;
 835                buf = p + 1;
 836                print = 1;
 837        }
 838        return 0;
 839}
 840
 841/*
 842 * '--color-words' algorithm can be described as:
 843 *
 844 *   1. collect a the minus/plus lines of a diff hunk, divided into
 845 *      minus-lines and plus-lines;
 846 *
 847 *   2. break both minus-lines and plus-lines into words and
 848 *      place them into two mmfile_t with one word for each line;
 849 *
 850 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 851 *
 852 * And for the common parts of the both file, we output the plus side text.
 853 * diff_words->current_plus is used to trace the current position of the plus file
 854 * which printed. diff_words->last_minus is used to trace the last minus word
 855 * printed.
 856 *
 857 * For '--graph' to work with '--color-words', we need to output the graph prefix
 858 * on each line of color words output. Generally, there are two conditions on
 859 * which we should output the prefix.
 860 *
 861 *   1. diff_words->last_minus == 0 &&
 862 *      diff_words->current_plus == diff_words->plus.text.ptr
 863 *
 864 *      that is: the plus text must start as a new line, and if there is no minus
 865 *      word printed, a graph prefix must be printed.
 866 *
 867 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 868 *      *(diff_words->current_plus - 1) == '\n'
 869 *
 870 *      that is: a graph prefix must be printed following a '\n'
 871 */
 872static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 873{
 874        if ((diff_words->last_minus == 0 &&
 875                diff_words->current_plus == diff_words->plus.text.ptr) ||
 876                (diff_words->current_plus > diff_words->plus.text.ptr &&
 877                *(diff_words->current_plus - 1) == '\n')) {
 878                return 1;
 879        } else {
 880                return 0;
 881        }
 882}
 883
 884static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 885{
 886        struct diff_words_data *diff_words = priv;
 887        struct diff_words_style *style = diff_words->style;
 888        int minus_first, minus_len, plus_first, plus_len;
 889        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 890        struct diff_options *opt = diff_words->opt;
 891        const char *line_prefix;
 892
 893        if (line[0] != '@' || parse_hunk_header(line, len,
 894                        &minus_first, &minus_len, &plus_first, &plus_len))
 895                return;
 896
 897        assert(opt);
 898        line_prefix = diff_line_prefix(opt);
 899
 900        /* POSIX requires that first be decremented by one if len == 0... */
 901        if (minus_len) {
 902                minus_begin = diff_words->minus.orig[minus_first].begin;
 903                minus_end =
 904                        diff_words->minus.orig[minus_first + minus_len - 1].end;
 905        } else
 906                minus_begin = minus_end =
 907                        diff_words->minus.orig[minus_first].end;
 908
 909        if (plus_len) {
 910                plus_begin = diff_words->plus.orig[plus_first].begin;
 911                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 912        } else
 913                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 914
 915        if (color_words_output_graph_prefix(diff_words)) {
 916                fputs(line_prefix, diff_words->opt->file);
 917        }
 918        if (diff_words->current_plus != plus_begin) {
 919                fn_out_diff_words_write_helper(diff_words->opt->file,
 920                                &style->ctx, style->newline,
 921                                plus_begin - diff_words->current_plus,
 922                                diff_words->current_plus, line_prefix);
 923                if (*(plus_begin - 1) == '\n')
 924                        fputs(line_prefix, diff_words->opt->file);
 925        }
 926        if (minus_begin != minus_end) {
 927                fn_out_diff_words_write_helper(diff_words->opt->file,
 928                                &style->old, style->newline,
 929                                minus_end - minus_begin, minus_begin,
 930                                line_prefix);
 931        }
 932        if (plus_begin != plus_end) {
 933                fn_out_diff_words_write_helper(diff_words->opt->file,
 934                                &style->new, style->newline,
 935                                plus_end - plus_begin, plus_begin,
 936                                line_prefix);
 937        }
 938
 939        diff_words->current_plus = plus_end;
 940        diff_words->last_minus = minus_first;
 941}
 942
 943/* This function starts looking at *begin, and returns 0 iff a word was found. */
 944static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 945                int *begin, int *end)
 946{
 947        if (word_regex && *begin < buffer->size) {
 948                regmatch_t match[1];
 949                if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 950                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 951                                        '\n', match[0].rm_eo - match[0].rm_so);
 952                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 953                        *begin += match[0].rm_so;
 954                        return *begin >= *end;
 955                }
 956                return -1;
 957        }
 958
 959        /* find the next word */
 960        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 961                (*begin)++;
 962        if (*begin >= buffer->size)
 963                return -1;
 964
 965        /* find the end of the word */
 966        *end = *begin + 1;
 967        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 968                (*end)++;
 969
 970        return 0;
 971}
 972
 973/*
 974 * This function splits the words in buffer->text, stores the list with
 975 * newline separator into out, and saves the offsets of the original words
 976 * in buffer->orig.
 977 */
 978static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 979                regex_t *word_regex)
 980{
 981        int i, j;
 982        long alloc = 0;
 983
 984        out->size = 0;
 985        out->ptr = NULL;
 986
 987        /* fake an empty "0th" word */
 988        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 989        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 990        buffer->orig_nr = 1;
 991
 992        for (i = 0; i < buffer->text.size; i++) {
 993                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 994                        return;
 995
 996                /* store original boundaries */
 997                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
 998                                buffer->orig_alloc);
 999                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
1000                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
1001                buffer->orig_nr++;
1002
1003                /* store one word */
1004                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
1005                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
1006                out->ptr[out->size + j - i] = '\n';
1007                out->size += j - i + 1;
1008
1009                i = j - 1;
1010        }
1011}
1012
1013/* this executes the word diff on the accumulated buffers */
1014static void diff_words_show(struct diff_words_data *diff_words)
1015{
1016        xpparam_t xpp;
1017        xdemitconf_t xecfg;
1018        mmfile_t minus, plus;
1019        struct diff_words_style *style = diff_words->style;
1020
1021        struct diff_options *opt = diff_words->opt;
1022        const char *line_prefix;
1023
1024        assert(opt);
1025        line_prefix = diff_line_prefix(opt);
1026
1027        /* special case: only removal */
1028        if (!diff_words->plus.text.size) {
1029                fputs(line_prefix, diff_words->opt->file);
1030                fn_out_diff_words_write_helper(diff_words->opt->file,
1031                        &style->old, style->newline,
1032                        diff_words->minus.text.size,
1033                        diff_words->minus.text.ptr, line_prefix);
1034                diff_words->minus.text.size = 0;
1035                return;
1036        }
1037
1038        diff_words->current_plus = diff_words->plus.text.ptr;
1039        diff_words->last_minus = 0;
1040
1041        memset(&xpp, 0, sizeof(xpp));
1042        memset(&xecfg, 0, sizeof(xecfg));
1043        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1044        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1045        xpp.flags = 0;
1046        /* as only the hunk header will be parsed, we need a 0-context */
1047        xecfg.ctxlen = 0;
1048        if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1049                          &xpp, &xecfg))
1050                die("unable to generate word diff");
1051        free(minus.ptr);
1052        free(plus.ptr);
1053        if (diff_words->current_plus != diff_words->plus.text.ptr +
1054                        diff_words->plus.text.size) {
1055                if (color_words_output_graph_prefix(diff_words))
1056                        fputs(line_prefix, diff_words->opt->file);
1057                fn_out_diff_words_write_helper(diff_words->opt->file,
1058                        &style->ctx, style->newline,
1059                        diff_words->plus.text.ptr + diff_words->plus.text.size
1060                        - diff_words->current_plus, diff_words->current_plus,
1061                        line_prefix);
1062        }
1063        diff_words->minus.text.size = diff_words->plus.text.size = 0;
1064}
1065
1066/* In "color-words" mode, show word-diff of words accumulated in the buffer */
1067static void diff_words_flush(struct emit_callback *ecbdata)
1068{
1069        if (ecbdata->diff_words->minus.text.size ||
1070            ecbdata->diff_words->plus.text.size)
1071                diff_words_show(ecbdata->diff_words);
1072}
1073
1074static void diff_filespec_load_driver(struct diff_filespec *one)
1075{
1076        /* Use already-loaded driver */
1077        if (one->driver)
1078                return;
1079
1080        if (S_ISREG(one->mode))
1081                one->driver = userdiff_find_by_path(one->path);
1082
1083        /* Fallback to default settings */
1084        if (!one->driver)
1085                one->driver = userdiff_find_by_name("default");
1086}
1087
1088static const char *userdiff_word_regex(struct diff_filespec *one)
1089{
1090        diff_filespec_load_driver(one);
1091        return one->driver->word_regex;
1092}
1093
1094static void init_diff_words_data(struct emit_callback *ecbdata,
1095                                 struct diff_options *orig_opts,
1096                                 struct diff_filespec *one,
1097                                 struct diff_filespec *two)
1098{
1099        int i;
1100        struct diff_options *o = xmalloc(sizeof(struct diff_options));
1101        memcpy(o, orig_opts, sizeof(struct diff_options));
1102
1103        ecbdata->diff_words =
1104                xcalloc(1, sizeof(struct diff_words_data));
1105        ecbdata->diff_words->type = o->word_diff;
1106        ecbdata->diff_words->opt = o;
1107        if (!o->word_regex)
1108                o->word_regex = userdiff_word_regex(one);
1109        if (!o->word_regex)
1110                o->word_regex = userdiff_word_regex(two);
1111        if (!o->word_regex)
1112                o->word_regex = diff_word_regex_cfg;
1113        if (o->word_regex) {
1114                ecbdata->diff_words->word_regex = (regex_t *)
1115                        xmalloc(sizeof(regex_t));
1116                if (regcomp(ecbdata->diff_words->word_regex,
1117                            o->word_regex,
1118                            REG_EXTENDED | REG_NEWLINE))
1119                        die ("Invalid regular expression: %s",
1120                             o->word_regex);
1121        }
1122        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1123                if (o->word_diff == diff_words_styles[i].type) {
1124                        ecbdata->diff_words->style =
1125                                &diff_words_styles[i];
1126                        break;
1127                }
1128        }
1129        if (want_color(o->use_color)) {
1130                struct diff_words_style *st = ecbdata->diff_words->style;
1131                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1132                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1133                st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1134        }
1135}
1136
1137static void free_diff_words_data(struct emit_callback *ecbdata)
1138{
1139        if (ecbdata->diff_words) {
1140                diff_words_flush(ecbdata);
1141                free (ecbdata->diff_words->opt);
1142                free (ecbdata->diff_words->minus.text.ptr);
1143                free (ecbdata->diff_words->minus.orig);
1144                free (ecbdata->diff_words->plus.text.ptr);
1145                free (ecbdata->diff_words->plus.orig);
1146                if (ecbdata->diff_words->word_regex) {
1147                        regfree(ecbdata->diff_words->word_regex);
1148                        free(ecbdata->diff_words->word_regex);
1149                }
1150                free(ecbdata->diff_words);
1151                ecbdata->diff_words = NULL;
1152        }
1153}
1154
1155const char *diff_get_color(int diff_use_color, enum color_diff ix)
1156{
1157        if (want_color(diff_use_color))
1158                return diff_colors[ix];
1159        return "";
1160}
1161
1162const char *diff_line_prefix(struct diff_options *opt)
1163{
1164        struct strbuf *msgbuf;
1165        if (!opt->output_prefix)
1166                return "";
1167
1168        msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1169        return msgbuf->buf;
1170}
1171
1172static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1173{
1174        const char *cp;
1175        unsigned long allot;
1176        size_t l = len;
1177
1178        if (ecb->truncate)
1179                return ecb->truncate(line, len);
1180        cp = line;
1181        allot = l;
1182        while (0 < l) {
1183                (void) utf8_width(&cp, &l);
1184                if (!cp)
1185                        break; /* truncated in the middle? */
1186        }
1187        return allot - l;
1188}
1189
1190static void find_lno(const char *line, struct emit_callback *ecbdata)
1191{
1192        const char *p;
1193        ecbdata->lno_in_preimage = 0;
1194        ecbdata->lno_in_postimage = 0;
1195        p = strchr(line, '-');
1196        if (!p)
1197                return; /* cannot happen */
1198        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1199        p = strchr(p, '+');
1200        if (!p)
1201                return; /* cannot happen */
1202        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1203}
1204
1205static void fn_out_consume(void *priv, char *line, unsigned long len)
1206{
1207        struct emit_callback *ecbdata = priv;
1208        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1209        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1210        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1211        struct diff_options *o = ecbdata->opt;
1212        const char *line_prefix = diff_line_prefix(o);
1213
1214        if (ecbdata->header) {
1215                fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1216                strbuf_reset(ecbdata->header);
1217                ecbdata->header = NULL;
1218        }
1219        *(ecbdata->found_changesp) = 1;
1220
1221        if (ecbdata->label_path[0]) {
1222                const char *name_a_tab, *name_b_tab;
1223
1224                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1225                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1226
1227                fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1228                        line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1229                fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1230                        line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1231                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1232        }
1233
1234        if (diff_suppress_blank_empty
1235            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1236                line[0] = '\n';
1237                len = 1;
1238        }
1239
1240        if (line[0] == '@') {
1241                if (ecbdata->diff_words)
1242                        diff_words_flush(ecbdata);
1243                len = sane_truncate_line(ecbdata, line, len);
1244                find_lno(line, ecbdata);
1245                emit_hunk_header(ecbdata, line, len);
1246                if (line[len-1] != '\n')
1247                        putc('\n', ecbdata->opt->file);
1248                return;
1249        }
1250
1251        if (len < 1) {
1252                emit_line(ecbdata->opt, reset, reset, line, len);
1253                if (ecbdata->diff_words
1254                    && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1255                        fputs("~\n", ecbdata->opt->file);
1256                return;
1257        }
1258
1259        if (ecbdata->diff_words) {
1260                if (line[0] == '-') {
1261                        diff_words_append(line, len,
1262                                          &ecbdata->diff_words->minus);
1263                        return;
1264                } else if (line[0] == '+') {
1265                        diff_words_append(line, len,
1266                                          &ecbdata->diff_words->plus);
1267                        return;
1268                } else if (starts_with(line, "\\ ")) {
1269                        /*
1270                         * Eat the "no newline at eof" marker as if we
1271                         * saw a "+" or "-" line with nothing on it,
1272                         * and return without diff_words_flush() to
1273                         * defer processing. If this is the end of
1274                         * preimage, more "+" lines may come after it.
1275                         */
1276                        return;
1277                }
1278                diff_words_flush(ecbdata);
1279                if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1280                        emit_line(ecbdata->opt, context, reset, line, len);
1281                        fputs("~\n", ecbdata->opt->file);
1282                } else {
1283                        /*
1284                         * Skip the prefix character, if any.  With
1285                         * diff_suppress_blank_empty, there may be
1286                         * none.
1287                         */
1288                        if (line[0] != '\n') {
1289                              line++;
1290                              len--;
1291                        }
1292                        emit_line(ecbdata->opt, context, reset, line, len);
1293                }
1294                return;
1295        }
1296
1297        switch (line[0]) {
1298        case '+':
1299                ecbdata->lno_in_postimage++;
1300                emit_add_line(reset, ecbdata, line + 1, len - 1);
1301                break;
1302        case '-':
1303                ecbdata->lno_in_preimage++;
1304                emit_del_line(reset, ecbdata, line + 1, len - 1);
1305                break;
1306        case ' ':
1307                ecbdata->lno_in_postimage++;
1308                ecbdata->lno_in_preimage++;
1309                emit_context_line(reset, ecbdata, line + 1, len - 1);
1310                break;
1311        default:
1312                /* incomplete line at the end */
1313                ecbdata->lno_in_preimage++;
1314                emit_line(ecbdata->opt,
1315                          diff_get_color(ecbdata->color_diff, DIFF_CONTEXT),
1316                          reset, line, len);
1317                break;
1318        }
1319}
1320
1321static char *pprint_rename(const char *a, const char *b)
1322{
1323        const char *old = a;
1324        const char *new = b;
1325        struct strbuf name = STRBUF_INIT;
1326        int pfx_length, sfx_length;
1327        int pfx_adjust_for_slash;
1328        int len_a = strlen(a);
1329        int len_b = strlen(b);
1330        int a_midlen, b_midlen;
1331        int qlen_a = quote_c_style(a, NULL, NULL, 0);
1332        int qlen_b = quote_c_style(b, NULL, NULL, 0);
1333
1334        if (qlen_a || qlen_b) {
1335                quote_c_style(a, &name, NULL, 0);
1336                strbuf_addstr(&name, " => ");
1337                quote_c_style(b, &name, NULL, 0);
1338                return strbuf_detach(&name, NULL);
1339        }
1340
1341        /* Find common prefix */
1342        pfx_length = 0;
1343        while (*old && *new && *old == *new) {
1344                if (*old == '/')
1345                        pfx_length = old - a + 1;
1346                old++;
1347                new++;
1348        }
1349
1350        /* Find common suffix */
1351        old = a + len_a;
1352        new = b + len_b;
1353        sfx_length = 0;
1354        /*
1355         * If there is a common prefix, it must end in a slash.  In
1356         * that case we let this loop run 1 into the prefix to see the
1357         * same slash.
1358         *
1359         * If there is no common prefix, we cannot do this as it would
1360         * underrun the input strings.
1361         */
1362        pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1363        while (a + pfx_length - pfx_adjust_for_slash <= old &&
1364               b + pfx_length - pfx_adjust_for_slash <= new &&
1365               *old == *new) {
1366                if (*old == '/')
1367                        sfx_length = len_a - (old - a);
1368                old--;
1369                new--;
1370        }
1371
1372        /*
1373         * pfx{mid-a => mid-b}sfx
1374         * {pfx-a => pfx-b}sfx
1375         * pfx{sfx-a => sfx-b}
1376         * name-a => name-b
1377         */
1378        a_midlen = len_a - pfx_length - sfx_length;
1379        b_midlen = len_b - pfx_length - sfx_length;
1380        if (a_midlen < 0)
1381                a_midlen = 0;
1382        if (b_midlen < 0)
1383                b_midlen = 0;
1384
1385        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1386        if (pfx_length + sfx_length) {
1387                strbuf_add(&name, a, pfx_length);
1388                strbuf_addch(&name, '{');
1389        }
1390        strbuf_add(&name, a + pfx_length, a_midlen);
1391        strbuf_addstr(&name, " => ");
1392        strbuf_add(&name, b + pfx_length, b_midlen);
1393        if (pfx_length + sfx_length) {
1394                strbuf_addch(&name, '}');
1395                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1396        }
1397        return strbuf_detach(&name, NULL);
1398}
1399
1400struct diffstat_t {
1401        int nr;
1402        int alloc;
1403        struct diffstat_file {
1404                char *from_name;
1405                char *name;
1406                char *print_name;
1407                unsigned is_unmerged:1;
1408                unsigned is_binary:1;
1409                unsigned is_renamed:1;
1410                unsigned is_interesting:1;
1411                uintmax_t added, deleted;
1412        } **files;
1413};
1414
1415static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1416                                          const char *name_a,
1417                                          const char *name_b)
1418{
1419        struct diffstat_file *x;
1420        x = xcalloc(1, sizeof(*x));
1421        ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
1422        diffstat->files[diffstat->nr++] = x;
1423        if (name_b) {
1424                x->from_name = xstrdup(name_a);
1425                x->name = xstrdup(name_b);
1426                x->is_renamed = 1;
1427        }
1428        else {
1429                x->from_name = NULL;
1430                x->name = xstrdup(name_a);
1431        }
1432        return x;
1433}
1434
1435static void diffstat_consume(void *priv, char *line, unsigned long len)
1436{
1437        struct diffstat_t *diffstat = priv;
1438        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1439
1440        if (line[0] == '+')
1441                x->added++;
1442        else if (line[0] == '-')
1443                x->deleted++;
1444}
1445
1446const char mime_boundary_leader[] = "------------";
1447
1448static int scale_linear(int it, int width, int max_change)
1449{
1450        if (!it)
1451                return 0;
1452        /*
1453         * make sure that at least one '-' or '+' is printed if
1454         * there is any change to this path. The easiest way is to
1455         * scale linearly as if the alloted width is one column shorter
1456         * than it is, and then add 1 to the result.
1457         */
1458        return 1 + (it * (width - 1) / max_change);
1459}
1460
1461static void show_name(FILE *file,
1462                      const char *prefix, const char *name, int len)
1463{
1464        fprintf(file, " %s%-*s |", prefix, len, name);
1465}
1466
1467static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1468{
1469        if (cnt <= 0)
1470                return;
1471        fprintf(file, "%s", set);
1472        while (cnt--)
1473                putc(ch, file);
1474        fprintf(file, "%s", reset);
1475}
1476
1477static void fill_print_name(struct diffstat_file *file)
1478{
1479        char *pname;
1480
1481        if (file->print_name)
1482                return;
1483
1484        if (!file->is_renamed) {
1485                struct strbuf buf = STRBUF_INIT;
1486                if (quote_c_style(file->name, &buf, NULL, 0)) {
1487                        pname = strbuf_detach(&buf, NULL);
1488                } else {
1489                        pname = file->name;
1490                        strbuf_release(&buf);
1491                }
1492        } else {
1493                pname = pprint_rename(file->from_name, file->name);
1494        }
1495        file->print_name = pname;
1496}
1497
1498int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1499{
1500        struct strbuf sb = STRBUF_INIT;
1501        int ret;
1502
1503        if (!files) {
1504                assert(insertions == 0 && deletions == 0);
1505                return fprintf(fp, "%s\n", " 0 files changed");
1506        }
1507
1508        strbuf_addf(&sb,
1509                    (files == 1) ? " %d file changed" : " %d files changed",
1510                    files);
1511
1512        /*
1513         * For binary diff, the caller may want to print "x files
1514         * changed" with insertions == 0 && deletions == 0.
1515         *
1516         * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1517         * is probably less confusing (i.e skip over "2 files changed
1518         * but nothing about added/removed lines? Is this a bug in Git?").
1519         */
1520        if (insertions || deletions == 0) {
1521                strbuf_addf(&sb,
1522                            (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1523                            insertions);
1524        }
1525
1526        if (deletions || insertions == 0) {
1527                strbuf_addf(&sb,
1528                            (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1529                            deletions);
1530        }
1531        strbuf_addch(&sb, '\n');
1532        ret = fputs(sb.buf, fp);
1533        strbuf_release(&sb);
1534        return ret;
1535}
1536
1537static void show_stats(struct diffstat_t *data, struct diff_options *options)
1538{
1539        int i, len, add, del, adds = 0, dels = 0;
1540        uintmax_t max_change = 0, max_len = 0;
1541        int total_files = data->nr, count;
1542        int width, name_width, graph_width, number_width = 0, bin_width = 0;
1543        const char *reset, *add_c, *del_c;
1544        const char *line_prefix = "";
1545        int extra_shown = 0;
1546
1547        if (data->nr == 0)
1548                return;
1549
1550        line_prefix = diff_line_prefix(options);
1551        count = options->stat_count ? options->stat_count : data->nr;
1552
1553        reset = diff_get_color_opt(options, DIFF_RESET);
1554        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1555        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1556
1557        /*
1558         * Find the longest filename and max number of changes
1559         */
1560        for (i = 0; (i < count) && (i < data->nr); i++) {
1561                struct diffstat_file *file = data->files[i];
1562                uintmax_t change = file->added + file->deleted;
1563
1564                if (!file->is_interesting && (change == 0)) {
1565                        count++; /* not shown == room for one more */
1566                        continue;
1567                }
1568                fill_print_name(file);
1569                len = strlen(file->print_name);
1570                if (max_len < len)
1571                        max_len = len;
1572
1573                if (file->is_unmerged) {
1574                        /* "Unmerged" is 8 characters */
1575                        bin_width = bin_width < 8 ? 8 : bin_width;
1576                        continue;
1577                }
1578                if (file->is_binary) {
1579                        /* "Bin XXX -> YYY bytes" */
1580                        int w = 14 + decimal_width(file->added)
1581                                + decimal_width(file->deleted);
1582                        bin_width = bin_width < w ? w : bin_width;
1583                        /* Display change counts aligned with "Bin" */
1584                        number_width = 3;
1585                        continue;
1586                }
1587
1588                if (max_change < change)
1589                        max_change = change;
1590        }
1591        count = i; /* where we can stop scanning in data->files[] */
1592
1593        /*
1594         * We have width = stat_width or term_columns() columns total.
1595         * We want a maximum of min(max_len, stat_name_width) for the name part.
1596         * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1597         * We also need 1 for " " and 4 + decimal_width(max_change)
1598         * for " | NNNN " and one the empty column at the end, altogether
1599         * 6 + decimal_width(max_change).
1600         *
1601         * If there's not enough space, we will use the smaller of
1602         * stat_name_width (if set) and 5/8*width for the filename,
1603         * and the rest for constant elements + graph part, but no more
1604         * than stat_graph_width for the graph part.
1605         * (5/8 gives 50 for filename and 30 for the constant parts + graph
1606         * for the standard terminal size).
1607         *
1608         * In other words: stat_width limits the maximum width, and
1609         * stat_name_width fixes the maximum width of the filename,
1610         * and is also used to divide available columns if there
1611         * aren't enough.
1612         *
1613         * Binary files are displayed with "Bin XXX -> YYY bytes"
1614         * instead of the change count and graph. This part is treated
1615         * similarly to the graph part, except that it is not
1616         * "scaled". If total width is too small to accommodate the
1617         * guaranteed minimum width of the filename part and the
1618         * separators and this message, this message will "overflow"
1619         * making the line longer than the maximum width.
1620         */
1621
1622        if (options->stat_width == -1)
1623                width = term_columns() - options->output_prefix_length;
1624        else
1625                width = options->stat_width ? options->stat_width : 80;
1626        number_width = decimal_width(max_change) > number_width ?
1627                decimal_width(max_change) : number_width;
1628
1629        if (options->stat_graph_width == -1)
1630                options->stat_graph_width = diff_stat_graph_width;
1631
1632        /*
1633         * Guarantee 3/8*16==6 for the graph part
1634         * and 5/8*16==10 for the filename part
1635         */
1636        if (width < 16 + 6 + number_width)
1637                width = 16 + 6 + number_width;
1638
1639        /*
1640         * First assign sizes that are wanted, ignoring available width.
1641         * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1642         * starting from "XXX" should fit in graph_width.
1643         */
1644        graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1645        if (options->stat_graph_width &&
1646            options->stat_graph_width < graph_width)
1647                graph_width = options->stat_graph_width;
1648
1649        name_width = (options->stat_name_width > 0 &&
1650                      options->stat_name_width < max_len) ?
1651                options->stat_name_width : max_len;
1652
1653        /*
1654         * Adjust adjustable widths not to exceed maximum width
1655         */
1656        if (name_width + number_width + 6 + graph_width > width) {
1657                if (graph_width > width * 3/8 - number_width - 6) {
1658                        graph_width = width * 3/8 - number_width - 6;
1659                        if (graph_width < 6)
1660                                graph_width = 6;
1661                }
1662
1663                if (options->stat_graph_width &&
1664                    graph_width > options->stat_graph_width)
1665                        graph_width = options->stat_graph_width;
1666                if (name_width > width - number_width - 6 - graph_width)
1667                        name_width = width - number_width - 6 - graph_width;
1668                else
1669                        graph_width = width - number_width - 6 - name_width;
1670        }
1671
1672        /*
1673         * From here name_width is the width of the name area,
1674         * and graph_width is the width of the graph area.
1675         * max_change is used to scale graph properly.
1676         */
1677        for (i = 0; i < count; i++) {
1678                const char *prefix = "";
1679                struct diffstat_file *file = data->files[i];
1680                char *name = file->print_name;
1681                uintmax_t added = file->added;
1682                uintmax_t deleted = file->deleted;
1683                int name_len;
1684
1685                if (!file->is_interesting && (added + deleted == 0))
1686                        continue;
1687
1688                /*
1689                 * "scale" the filename
1690                 */
1691                len = name_width;
1692                name_len = strlen(name);
1693                if (name_width < name_len) {
1694                        char *slash;
1695                        prefix = "...";
1696                        len -= 3;
1697                        name += name_len - len;
1698                        slash = strchr(name, '/');
1699                        if (slash)
1700                                name = slash;
1701                }
1702
1703                if (file->is_binary) {
1704                        fprintf(options->file, "%s", line_prefix);
1705                        show_name(options->file, prefix, name, len);
1706                        fprintf(options->file, " %*s", number_width, "Bin");
1707                        if (!added && !deleted) {
1708                                putc('\n', options->file);
1709                                continue;
1710                        }
1711                        fprintf(options->file, " %s%"PRIuMAX"%s",
1712                                del_c, deleted, reset);
1713                        fprintf(options->file, " -> ");
1714                        fprintf(options->file, "%s%"PRIuMAX"%s",
1715                                add_c, added, reset);
1716                        fprintf(options->file, " bytes");
1717                        fprintf(options->file, "\n");
1718                        continue;
1719                }
1720                else if (file->is_unmerged) {
1721                        fprintf(options->file, "%s", line_prefix);
1722                        show_name(options->file, prefix, name, len);
1723                        fprintf(options->file, " Unmerged\n");
1724                        continue;
1725                }
1726
1727                /*
1728                 * scale the add/delete
1729                 */
1730                add = added;
1731                del = deleted;
1732
1733                if (graph_width <= max_change) {
1734                        int total = scale_linear(add + del, graph_width, max_change);
1735                        if (total < 2 && add && del)
1736                                /* width >= 2 due to the sanity check */
1737                                total = 2;
1738                        if (add < del) {
1739                                add = scale_linear(add, graph_width, max_change);
1740                                del = total - add;
1741                        } else {
1742                                del = scale_linear(del, graph_width, max_change);
1743                                add = total - del;
1744                        }
1745                }
1746                fprintf(options->file, "%s", line_prefix);
1747                show_name(options->file, prefix, name, len);
1748                fprintf(options->file, " %*"PRIuMAX"%s",
1749                        number_width, added + deleted,
1750                        added + deleted ? " " : "");
1751                show_graph(options->file, '+', add, add_c, reset);
1752                show_graph(options->file, '-', del, del_c, reset);
1753                fprintf(options->file, "\n");
1754        }
1755
1756        for (i = 0; i < data->nr; i++) {
1757                struct diffstat_file *file = data->files[i];
1758                uintmax_t added = file->added;
1759                uintmax_t deleted = file->deleted;
1760
1761                if (file->is_unmerged ||
1762                    (!file->is_interesting && (added + deleted == 0))) {
1763                        total_files--;
1764                        continue;
1765                }
1766
1767                if (!file->is_binary) {
1768                        adds += added;
1769                        dels += deleted;
1770                }
1771                if (i < count)
1772                        continue;
1773                if (!extra_shown)
1774                        fprintf(options->file, "%s ...\n", line_prefix);
1775                extra_shown = 1;
1776        }
1777        fprintf(options->file, "%s", line_prefix);
1778        print_stat_summary(options->file, total_files, adds, dels);
1779}
1780
1781static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1782{
1783        int i, adds = 0, dels = 0, total_files = data->nr;
1784
1785        if (data->nr == 0)
1786                return;
1787
1788        for (i = 0; i < data->nr; i++) {
1789                int added = data->files[i]->added;
1790                int deleted= data->files[i]->deleted;
1791
1792                if (data->files[i]->is_unmerged ||
1793                    (!data->files[i]->is_interesting && (added + deleted == 0))) {
1794                        total_files--;
1795                } else if (!data->files[i]->is_binary) { /* don't count bytes */
1796                        adds += added;
1797                        dels += deleted;
1798                }
1799        }
1800        fprintf(options->file, "%s", diff_line_prefix(options));
1801        print_stat_summary(options->file, total_files, adds, dels);
1802}
1803
1804static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1805{
1806        int i;
1807
1808        if (data->nr == 0)
1809                return;
1810
1811        for (i = 0; i < data->nr; i++) {
1812                struct diffstat_file *file = data->files[i];
1813
1814                fprintf(options->file, "%s", diff_line_prefix(options));
1815
1816                if (file->is_binary)
1817                        fprintf(options->file, "-\t-\t");
1818                else
1819                        fprintf(options->file,
1820                                "%"PRIuMAX"\t%"PRIuMAX"\t",
1821                                file->added, file->deleted);
1822                if (options->line_termination) {
1823                        fill_print_name(file);
1824                        if (!file->is_renamed)
1825                                write_name_quoted(file->name, options->file,
1826                                                  options->line_termination);
1827                        else {
1828                                fputs(file->print_name, options->file);
1829                                putc(options->line_termination, options->file);
1830                        }
1831                } else {
1832                        if (file->is_renamed) {
1833                                putc('\0', options->file);
1834                                write_name_quoted(file->from_name, options->file, '\0');
1835                        }
1836                        write_name_quoted(file->name, options->file, '\0');
1837                }
1838        }
1839}
1840
1841struct dirstat_file {
1842        const char *name;
1843        unsigned long changed;
1844};
1845
1846struct dirstat_dir {
1847        struct dirstat_file *files;
1848        int alloc, nr, permille, cumulative;
1849};
1850
1851static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1852                unsigned long changed, const char *base, int baselen)
1853{
1854        unsigned long this_dir = 0;
1855        unsigned int sources = 0;
1856        const char *line_prefix = diff_line_prefix(opt);
1857
1858        while (dir->nr) {
1859                struct dirstat_file *f = dir->files;
1860                int namelen = strlen(f->name);
1861                unsigned long this;
1862                char *slash;
1863
1864                if (namelen < baselen)
1865                        break;
1866                if (memcmp(f->name, base, baselen))
1867                        break;
1868                slash = strchr(f->name + baselen, '/');
1869                if (slash) {
1870                        int newbaselen = slash + 1 - f->name;
1871                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1872                        sources++;
1873                } else {
1874                        this = f->changed;
1875                        dir->files++;
1876                        dir->nr--;
1877                        sources += 2;
1878                }
1879                this_dir += this;
1880        }
1881
1882        /*
1883         * We don't report dirstat's for
1884         *  - the top level
1885         *  - or cases where everything came from a single directory
1886         *    under this directory (sources == 1).
1887         */
1888        if (baselen && sources != 1) {
1889                if (this_dir) {
1890                        int permille = this_dir * 1000 / changed;
1891                        if (permille >= dir->permille) {
1892                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1893                                        permille / 10, permille % 10, baselen, base);
1894                                if (!dir->cumulative)
1895                                        return 0;
1896                        }
1897                }
1898        }
1899        return this_dir;
1900}
1901
1902static int dirstat_compare(const void *_a, const void *_b)
1903{
1904        const struct dirstat_file *a = _a;
1905        const struct dirstat_file *b = _b;
1906        return strcmp(a->name, b->name);
1907}
1908
1909static void show_dirstat(struct diff_options *options)
1910{
1911        int i;
1912        unsigned long changed;
1913        struct dirstat_dir dir;
1914        struct diff_queue_struct *q = &diff_queued_diff;
1915
1916        dir.files = NULL;
1917        dir.alloc = 0;
1918        dir.nr = 0;
1919        dir.permille = options->dirstat_permille;
1920        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1921
1922        changed = 0;
1923        for (i = 0; i < q->nr; i++) {
1924                struct diff_filepair *p = q->queue[i];
1925                const char *name;
1926                unsigned long copied, added, damage;
1927                int content_changed;
1928
1929                name = p->two->path ? p->two->path : p->one->path;
1930
1931                if (p->one->sha1_valid && p->two->sha1_valid)
1932                        content_changed = hashcmp(p->one->sha1, p->two->sha1);
1933                else
1934                        content_changed = 1;
1935
1936                if (!content_changed) {
1937                        /*
1938                         * The SHA1 has not changed, so pre-/post-content is
1939                         * identical. We can therefore skip looking at the
1940                         * file contents altogether.
1941                         */
1942                        damage = 0;
1943                        goto found_damage;
1944                }
1945
1946                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1947                        /*
1948                         * In --dirstat-by-file mode, we don't really need to
1949                         * look at the actual file contents at all.
1950                         * The fact that the SHA1 changed is enough for us to
1951                         * add this file to the list of results
1952                         * (with each file contributing equal damage).
1953                         */
1954                        damage = 1;
1955                        goto found_damage;
1956                }
1957
1958                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1959                        diff_populate_filespec(p->one, 0);
1960                        diff_populate_filespec(p->two, 0);
1961                        diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1962                                               &copied, &added);
1963                        diff_free_filespec_data(p->one);
1964                        diff_free_filespec_data(p->two);
1965                } else if (DIFF_FILE_VALID(p->one)) {
1966                        diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
1967                        copied = added = 0;
1968                        diff_free_filespec_data(p->one);
1969                } else if (DIFF_FILE_VALID(p->two)) {
1970                        diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
1971                        copied = 0;
1972                        added = p->two->size;
1973                        diff_free_filespec_data(p->two);
1974                } else
1975                        continue;
1976
1977                /*
1978                 * Original minus copied is the removed material,
1979                 * added is the new material.  They are both damages
1980                 * made to the preimage.
1981                 * If the resulting damage is zero, we know that
1982                 * diffcore_count_changes() considers the two entries to
1983                 * be identical, but since content_changed is true, we
1984                 * know that there must have been _some_ kind of change,
1985                 * so we force all entries to have damage > 0.
1986                 */
1987                damage = (p->one->size - copied) + added;
1988                if (!damage)
1989                        damage = 1;
1990
1991found_damage:
1992                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1993                dir.files[dir.nr].name = name;
1994                dir.files[dir.nr].changed = damage;
1995                changed += damage;
1996                dir.nr++;
1997        }
1998
1999        /* This can happen even with many files, if everything was renames */
2000        if (!changed)
2001                return;
2002
2003        /* Show all directories with more than x% of the changes */
2004        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
2005        gather_dirstat(options, &dir, changed, "", 0);
2006}
2007
2008static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
2009{
2010        int i;
2011        unsigned long changed;
2012        struct dirstat_dir dir;
2013
2014        if (data->nr == 0)
2015                return;
2016
2017        dir.files = NULL;
2018        dir.alloc = 0;
2019        dir.nr = 0;
2020        dir.permille = options->dirstat_permille;
2021        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2022
2023        changed = 0;
2024        for (i = 0; i < data->nr; i++) {
2025                struct diffstat_file *file = data->files[i];
2026                unsigned long damage = file->added + file->deleted;
2027                if (file->is_binary)
2028                        /*
2029                         * binary files counts bytes, not lines. Must find some
2030                         * way to normalize binary bytes vs. textual lines.
2031                         * The following heuristic assumes that there are 64
2032                         * bytes per "line".
2033                         * This is stupid and ugly, but very cheap...
2034                         */
2035                        damage = (damage + 63) / 64;
2036                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2037                dir.files[dir.nr].name = file->name;
2038                dir.files[dir.nr].changed = damage;
2039                changed += damage;
2040                dir.nr++;
2041        }
2042
2043        /* This can happen even with many files, if everything was renames */
2044        if (!changed)
2045                return;
2046
2047        /* Show all directories with more than x% of the changes */
2048        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
2049        gather_dirstat(options, &dir, changed, "", 0);
2050}
2051
2052static void free_diffstat_info(struct diffstat_t *diffstat)
2053{
2054        int i;
2055        for (i = 0; i < diffstat->nr; i++) {
2056                struct diffstat_file *f = diffstat->files[i];
2057                if (f->name != f->print_name)
2058                        free(f->print_name);
2059                free(f->name);
2060                free(f->from_name);
2061                free(f);
2062        }
2063        free(diffstat->files);
2064}
2065
2066struct checkdiff_t {
2067        const char *filename;
2068        int lineno;
2069        int conflict_marker_size;
2070        struct diff_options *o;
2071        unsigned ws_rule;
2072        unsigned status;
2073};
2074
2075static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2076{
2077        char firstchar;
2078        int cnt;
2079
2080        if (len < marker_size + 1)
2081                return 0;
2082        firstchar = line[0];
2083        switch (firstchar) {
2084        case '=': case '>': case '<': case '|':
2085                break;
2086        default:
2087                return 0;
2088        }
2089        for (cnt = 1; cnt < marker_size; cnt++)
2090                if (line[cnt] != firstchar)
2091                        return 0;
2092        /* line[1] thru line[marker_size-1] are same as firstchar */
2093        if (len < marker_size + 1 || !isspace(line[marker_size]))
2094                return 0;
2095        return 1;
2096}
2097
2098static void checkdiff_consume(void *priv, char *line, unsigned long len)
2099{
2100        struct checkdiff_t *data = priv;
2101        int marker_size = data->conflict_marker_size;
2102        const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2103        const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2104        const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2105        char *err;
2106        const char *line_prefix;
2107
2108        assert(data->o);
2109        line_prefix = diff_line_prefix(data->o);
2110
2111        if (line[0] == '+') {
2112                unsigned bad;
2113                data->lineno++;
2114                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2115                        data->status |= 1;
2116                        fprintf(data->o->file,
2117                                "%s%s:%d: leftover conflict marker\n",
2118                                line_prefix, data->filename, data->lineno);
2119                }
2120                bad = ws_check(line + 1, len - 1, data->ws_rule);
2121                if (!bad)
2122                        return;
2123                data->status |= bad;
2124                err = whitespace_error_string(bad);
2125                fprintf(data->o->file, "%s%s:%d: %s.\n",
2126                        line_prefix, data->filename, data->lineno, err);
2127                free(err);
2128                emit_line(data->o, set, reset, line, 1);
2129                ws_check_emit(line + 1, len - 1, data->ws_rule,
2130                              data->o->file, set, reset, ws);
2131        } else if (line[0] == ' ') {
2132                data->lineno++;
2133        } else if (line[0] == '@') {
2134                char *plus = strchr(line, '+');
2135                if (plus)
2136                        data->lineno = strtol(plus, NULL, 10) - 1;
2137                else
2138                        die("invalid diff");
2139        }
2140}
2141
2142static unsigned char *deflate_it(char *data,
2143                                 unsigned long size,
2144                                 unsigned long *result_size)
2145{
2146        int bound;
2147        unsigned char *deflated;
2148        git_zstream stream;
2149
2150        git_deflate_init(&stream, zlib_compression_level);
2151        bound = git_deflate_bound(&stream, size);
2152        deflated = xmalloc(bound);
2153        stream.next_out = deflated;
2154        stream.avail_out = bound;
2155
2156        stream.next_in = (unsigned char *)data;
2157        stream.avail_in = size;
2158        while (git_deflate(&stream, Z_FINISH) == Z_OK)
2159                ; /* nothing */
2160        git_deflate_end(&stream);
2161        *result_size = stream.total_out;
2162        return deflated;
2163}
2164
2165static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2166                                  const char *prefix)
2167{
2168        void *cp;
2169        void *delta;
2170        void *deflated;
2171        void *data;
2172        unsigned long orig_size;
2173        unsigned long delta_size;
2174        unsigned long deflate_size;
2175        unsigned long data_size;
2176
2177        /* We could do deflated delta, or we could do just deflated two,
2178         * whichever is smaller.
2179         */
2180        delta = NULL;
2181        deflated = deflate_it(two->ptr, two->size, &deflate_size);
2182        if (one->size && two->size) {
2183                delta = diff_delta(one->ptr, one->size,
2184                                   two->ptr, two->size,
2185                                   &delta_size, deflate_size);
2186                if (delta) {
2187                        void *to_free = delta;
2188                        orig_size = delta_size;
2189                        delta = deflate_it(delta, delta_size, &delta_size);
2190                        free(to_free);
2191                }
2192        }
2193
2194        if (delta && delta_size < deflate_size) {
2195                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2196                free(deflated);
2197                data = delta;
2198                data_size = delta_size;
2199        }
2200        else {
2201                fprintf(file, "%sliteral %lu\n", prefix, two->size);
2202                free(delta);
2203                data = deflated;
2204                data_size = deflate_size;
2205        }
2206
2207        /* emit data encoded in base85 */
2208        cp = data;
2209        while (data_size) {
2210                int bytes = (52 < data_size) ? 52 : data_size;
2211                char line[70];
2212                data_size -= bytes;
2213                if (bytes <= 26)
2214                        line[0] = bytes + 'A' - 1;
2215                else
2216                        line[0] = bytes - 26 + 'a' - 1;
2217                encode_85(line + 1, cp, bytes);
2218                cp = (char *) cp + bytes;
2219                fprintf(file, "%s", prefix);
2220                fputs(line, file);
2221                fputc('\n', file);
2222        }
2223        fprintf(file, "%s\n", prefix);
2224        free(data);
2225}
2226
2227static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2228                             const char *prefix)
2229{
2230        fprintf(file, "%sGIT binary patch\n", prefix);
2231        emit_binary_diff_body(file, one, two, prefix);
2232        emit_binary_diff_body(file, two, one, prefix);
2233}
2234
2235int diff_filespec_is_binary(struct diff_filespec *one)
2236{
2237        if (one->is_binary == -1) {
2238                diff_filespec_load_driver(one);
2239                if (one->driver->binary != -1)
2240                        one->is_binary = one->driver->binary;
2241                else {
2242                        if (!one->data && DIFF_FILE_VALID(one))
2243                                diff_populate_filespec(one, CHECK_BINARY);
2244                        if (one->is_binary == -1 && one->data)
2245                                one->is_binary = buffer_is_binary(one->data,
2246                                                one->size);
2247                        if (one->is_binary == -1)
2248                                one->is_binary = 0;
2249                }
2250        }
2251        return one->is_binary;
2252}
2253
2254static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2255{
2256        diff_filespec_load_driver(one);
2257        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2258}
2259
2260void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2261{
2262        if (!options->a_prefix)
2263                options->a_prefix = a;
2264        if (!options->b_prefix)
2265                options->b_prefix = b;
2266}
2267
2268struct userdiff_driver *get_textconv(struct diff_filespec *one)
2269{
2270        if (!DIFF_FILE_VALID(one))
2271                return NULL;
2272
2273        diff_filespec_load_driver(one);
2274        return userdiff_get_textconv(one->driver);
2275}
2276
2277static void builtin_diff(const char *name_a,
2278                         const char *name_b,
2279                         struct diff_filespec *one,
2280                         struct diff_filespec *two,
2281                         const char *xfrm_msg,
2282                         int must_show_header,
2283                         struct diff_options *o,
2284                         int complete_rewrite)
2285{
2286        mmfile_t mf1, mf2;
2287        const char *lbl[2];
2288        char *a_one, *b_two;
2289        const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2290        const char *reset = diff_get_color_opt(o, DIFF_RESET);
2291        const char *a_prefix, *b_prefix;
2292        struct userdiff_driver *textconv_one = NULL;
2293        struct userdiff_driver *textconv_two = NULL;
2294        struct strbuf header = STRBUF_INIT;
2295        const char *line_prefix = diff_line_prefix(o);
2296
2297        if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2298                        (!one->mode || S_ISGITLINK(one->mode)) &&
2299                        (!two->mode || S_ISGITLINK(two->mode))) {
2300                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2301                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2302                show_submodule_summary(o->file, one->path ? one->path : two->path,
2303                                line_prefix,
2304                                one->sha1, two->sha1, two->dirty_submodule,
2305                                meta, del, add, reset);
2306                return;
2307        }
2308
2309        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2310                textconv_one = get_textconv(one);
2311                textconv_two = get_textconv(two);
2312        }
2313
2314        diff_set_mnemonic_prefix(o, "a/", "b/");
2315        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2316                a_prefix = o->b_prefix;
2317                b_prefix = o->a_prefix;
2318        } else {
2319                a_prefix = o->a_prefix;
2320                b_prefix = o->b_prefix;
2321        }
2322
2323        /* Never use a non-valid filename anywhere if at all possible */
2324        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2325        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2326
2327        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2328        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2329        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2330        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2331        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2332        if (lbl[0][0] == '/') {
2333                /* /dev/null */
2334                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2335                if (xfrm_msg)
2336                        strbuf_addstr(&header, xfrm_msg);
2337                must_show_header = 1;
2338        }
2339        else if (lbl[1][0] == '/') {
2340                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2341                if (xfrm_msg)
2342                        strbuf_addstr(&header, xfrm_msg);
2343                must_show_header = 1;
2344        }
2345        else {
2346                if (one->mode != two->mode) {
2347                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2348                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2349                        must_show_header = 1;
2350                }
2351                if (xfrm_msg)
2352                        strbuf_addstr(&header, xfrm_msg);
2353
2354                /*
2355                 * we do not run diff between different kind
2356                 * of objects.
2357                 */
2358                if ((one->mode ^ two->mode) & S_IFMT)
2359                        goto free_ab_and_return;
2360                if (complete_rewrite &&
2361                    (textconv_one || !diff_filespec_is_binary(one)) &&
2362                    (textconv_two || !diff_filespec_is_binary(two))) {
2363                        fprintf(o->file, "%s", header.buf);
2364                        strbuf_reset(&header);
2365                        emit_rewrite_diff(name_a, name_b, one, two,
2366                                                textconv_one, textconv_two, o);
2367                        o->found_changes = 1;
2368                        goto free_ab_and_return;
2369                }
2370        }
2371
2372        if (o->irreversible_delete && lbl[1][0] == '/') {
2373                fprintf(o->file, "%s", header.buf);
2374                strbuf_reset(&header);
2375                goto free_ab_and_return;
2376        } else if (!DIFF_OPT_TST(o, TEXT) &&
2377            ( (!textconv_one && diff_filespec_is_binary(one)) ||
2378              (!textconv_two && diff_filespec_is_binary(two)) )) {
2379                if (!one->data && !two->data &&
2380                    S_ISREG(one->mode) && S_ISREG(two->mode) &&
2381                    !DIFF_OPT_TST(o, BINARY)) {
2382                        if (!hashcmp(one->sha1, two->sha1)) {
2383                                if (must_show_header)
2384                                        fprintf(o->file, "%s", header.buf);
2385                                goto free_ab_and_return;
2386                        }
2387                        fprintf(o->file, "%s", header.buf);
2388                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2389                                line_prefix, lbl[0], lbl[1]);
2390                        goto free_ab_and_return;
2391                }
2392                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2393                        die("unable to read files to diff");
2394                /* Quite common confusing case */
2395                if (mf1.size == mf2.size &&
2396                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2397                        if (must_show_header)
2398                                fprintf(o->file, "%s", header.buf);
2399                        goto free_ab_and_return;
2400                }
2401                fprintf(o->file, "%s", header.buf);
2402                strbuf_reset(&header);
2403                if (DIFF_OPT_TST(o, BINARY))
2404                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2405                else
2406                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2407                                line_prefix, lbl[0], lbl[1]);
2408                o->found_changes = 1;
2409        } else {
2410                /* Crazy xdl interfaces.. */
2411                const char *diffopts = getenv("GIT_DIFF_OPTS");
2412                const char *v;
2413                xpparam_t xpp;
2414                xdemitconf_t xecfg;
2415                struct emit_callback ecbdata;
2416                const struct userdiff_funcname *pe;
2417
2418                if (must_show_header) {
2419                        fprintf(o->file, "%s", header.buf);
2420                        strbuf_reset(&header);
2421                }
2422
2423                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2424                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2425
2426                pe = diff_funcname_pattern(one);
2427                if (!pe)
2428                        pe = diff_funcname_pattern(two);
2429
2430                memset(&xpp, 0, sizeof(xpp));
2431                memset(&xecfg, 0, sizeof(xecfg));
2432                memset(&ecbdata, 0, sizeof(ecbdata));
2433                ecbdata.label_path = lbl;
2434                ecbdata.color_diff = want_color(o->use_color);
2435                ecbdata.found_changesp = &o->found_changes;
2436                ecbdata.ws_rule = whitespace_rule(name_b);
2437                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2438                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2439                ecbdata.opt = o;
2440                ecbdata.header = header.len ? &header : NULL;
2441                xpp.flags = o->xdl_opts;
2442                xecfg.ctxlen = o->context;
2443                xecfg.interhunkctxlen = o->interhunkcontext;
2444                xecfg.flags = XDL_EMIT_FUNCNAMES;
2445                if (DIFF_OPT_TST(o, FUNCCONTEXT))
2446                        xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2447                if (pe)
2448                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2449                if (!diffopts)
2450                        ;
2451                else if (skip_prefix(diffopts, "--unified=", &v))
2452                        xecfg.ctxlen = strtoul(v, NULL, 10);
2453                else if (skip_prefix(diffopts, "-u", &v))
2454                        xecfg.ctxlen = strtoul(v, NULL, 10);
2455                if (o->word_diff)
2456                        init_diff_words_data(&ecbdata, o, one, two);
2457                if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2458                                  &xpp, &xecfg))
2459                        die("unable to generate diff for %s", one->path);
2460                if (o->word_diff)
2461                        free_diff_words_data(&ecbdata);
2462                if (textconv_one)
2463                        free(mf1.ptr);
2464                if (textconv_two)
2465                        free(mf2.ptr);
2466                xdiff_clear_find_func(&xecfg);
2467        }
2468
2469 free_ab_and_return:
2470        strbuf_release(&header);
2471        diff_free_filespec_data(one);
2472        diff_free_filespec_data(two);
2473        free(a_one);
2474        free(b_two);
2475        return;
2476}
2477
2478static void builtin_diffstat(const char *name_a, const char *name_b,
2479                             struct diff_filespec *one,
2480                             struct diff_filespec *two,
2481                             struct diffstat_t *diffstat,
2482                             struct diff_options *o,
2483                             struct diff_filepair *p)
2484{
2485        mmfile_t mf1, mf2;
2486        struct diffstat_file *data;
2487        int same_contents;
2488        int complete_rewrite = 0;
2489
2490        if (!DIFF_PAIR_UNMERGED(p)) {
2491                if (p->status == DIFF_STATUS_MODIFIED && p->score)
2492                        complete_rewrite = 1;
2493        }
2494
2495        data = diffstat_add(diffstat, name_a, name_b);
2496        data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2497
2498        if (!one || !two) {
2499                data->is_unmerged = 1;
2500                return;
2501        }
2502
2503        same_contents = !hashcmp(one->sha1, two->sha1);
2504
2505        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2506                data->is_binary = 1;
2507                if (same_contents) {
2508                        data->added = 0;
2509                        data->deleted = 0;
2510                } else {
2511                        data->added = diff_filespec_size(two);
2512                        data->deleted = diff_filespec_size(one);
2513                }
2514        }
2515
2516        else if (complete_rewrite) {
2517                diff_populate_filespec(one, 0);
2518                diff_populate_filespec(two, 0);
2519                data->deleted = count_lines(one->data, one->size);
2520                data->added = count_lines(two->data, two->size);
2521        }
2522
2523        else if (!same_contents) {
2524                /* Crazy xdl interfaces.. */
2525                xpparam_t xpp;
2526                xdemitconf_t xecfg;
2527
2528                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2529                        die("unable to read files to diff");
2530
2531                memset(&xpp, 0, sizeof(xpp));
2532                memset(&xecfg, 0, sizeof(xecfg));
2533                xpp.flags = o->xdl_opts;
2534                xecfg.ctxlen = o->context;
2535                xecfg.interhunkctxlen = o->interhunkcontext;
2536                if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2537                                  &xpp, &xecfg))
2538                        die("unable to generate diffstat for %s", one->path);
2539        }
2540
2541        diff_free_filespec_data(one);
2542        diff_free_filespec_data(two);
2543}
2544
2545static void builtin_checkdiff(const char *name_a, const char *name_b,
2546                              const char *attr_path,
2547                              struct diff_filespec *one,
2548                              struct diff_filespec *two,
2549                              struct diff_options *o)
2550{
2551        mmfile_t mf1, mf2;
2552        struct checkdiff_t data;
2553
2554        if (!two)
2555                return;
2556
2557        memset(&data, 0, sizeof(data));
2558        data.filename = name_b ? name_b : name_a;
2559        data.lineno = 0;
2560        data.o = o;
2561        data.ws_rule = whitespace_rule(attr_path);
2562        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2563
2564        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2565                die("unable to read files to diff");
2566
2567        /*
2568         * All the other codepaths check both sides, but not checking
2569         * the "old" side here is deliberate.  We are checking the newly
2570         * introduced changes, and as long as the "new" side is text, we
2571         * can and should check what it introduces.
2572         */
2573        if (diff_filespec_is_binary(two))
2574                goto free_and_return;
2575        else {
2576                /* Crazy xdl interfaces.. */
2577                xpparam_t xpp;
2578                xdemitconf_t xecfg;
2579
2580                memset(&xpp, 0, sizeof(xpp));
2581                memset(&xecfg, 0, sizeof(xecfg));
2582                xecfg.ctxlen = 1; /* at least one context line */
2583                xpp.flags = 0;
2584                if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2585                                  &xpp, &xecfg))
2586                        die("unable to generate checkdiff for %s", one->path);
2587
2588                if (data.ws_rule & WS_BLANK_AT_EOF) {
2589                        struct emit_callback ecbdata;
2590                        int blank_at_eof;
2591
2592                        ecbdata.ws_rule = data.ws_rule;
2593                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2594                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2595
2596                        if (blank_at_eof) {
2597                                static char *err;
2598                                if (!err)
2599                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2600                                fprintf(o->file, "%s:%d: %s.\n",
2601                                        data.filename, blank_at_eof, err);
2602                                data.status = 1; /* report errors */
2603                        }
2604                }
2605        }
2606 free_and_return:
2607        diff_free_filespec_data(one);
2608        diff_free_filespec_data(two);
2609        if (data.status)
2610                DIFF_OPT_SET(o, CHECK_FAILED);
2611}
2612
2613struct diff_filespec *alloc_filespec(const char *path)
2614{
2615        struct diff_filespec *spec;
2616
2617        FLEXPTR_ALLOC_STR(spec, path, path);
2618        spec->count = 1;
2619        spec->is_binary = -1;
2620        return spec;
2621}
2622
2623void free_filespec(struct diff_filespec *spec)
2624{
2625        if (!--spec->count) {
2626                diff_free_filespec_data(spec);
2627                free(spec);
2628        }
2629}
2630
2631void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2632                   int sha1_valid, unsigned short mode)
2633{
2634        if (mode) {
2635                spec->mode = canon_mode(mode);
2636                hashcpy(spec->sha1, sha1);
2637                spec->sha1_valid = sha1_valid;
2638        }
2639}
2640
2641/*
2642 * Given a name and sha1 pair, if the index tells us the file in
2643 * the work tree has that object contents, return true, so that
2644 * prepare_temp_file() does not have to inflate and extract.
2645 */
2646static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2647{
2648        const struct cache_entry *ce;
2649        struct stat st;
2650        int pos, len;
2651
2652        /*
2653         * We do not read the cache ourselves here, because the
2654         * benchmark with my previous version that always reads cache
2655         * shows that it makes things worse for diff-tree comparing
2656         * two linux-2.6 kernel trees in an already checked out work
2657         * tree.  This is because most diff-tree comparisons deal with
2658         * only a small number of files, while reading the cache is
2659         * expensive for a large project, and its cost outweighs the
2660         * savings we get by not inflating the object to a temporary
2661         * file.  Practically, this code only helps when we are used
2662         * by diff-cache --cached, which does read the cache before
2663         * calling us.
2664         */
2665        if (!active_cache)
2666                return 0;
2667
2668        /* We want to avoid the working directory if our caller
2669         * doesn't need the data in a normal file, this system
2670         * is rather slow with its stat/open/mmap/close syscalls,
2671         * and the object is contained in a pack file.  The pack
2672         * is probably already open and will be faster to obtain
2673         * the data through than the working directory.  Loose
2674         * objects however would tend to be slower as they need
2675         * to be individually opened and inflated.
2676         */
2677        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2678                return 0;
2679
2680        len = strlen(name);
2681        pos = cache_name_pos(name, len);
2682        if (pos < 0)
2683                return 0;
2684        ce = active_cache[pos];
2685
2686        /*
2687         * This is not the sha1 we are looking for, or
2688         * unreusable because it is not a regular file.
2689         */
2690        if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2691                return 0;
2692
2693        /*
2694         * If ce is marked as "assume unchanged", there is no
2695         * guarantee that work tree matches what we are looking for.
2696         */
2697        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2698                return 0;
2699
2700        /*
2701         * If ce matches the file in the work tree, we can reuse it.
2702         */
2703        if (ce_uptodate(ce) ||
2704            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2705                return 1;
2706
2707        return 0;
2708}
2709
2710static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2711{
2712        struct strbuf buf = STRBUF_INIT;
2713        char *dirty = "";
2714
2715        /* Are we looking at the work tree? */
2716        if (s->dirty_submodule)
2717                dirty = "-dirty";
2718
2719        strbuf_addf(&buf, "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2720        s->size = buf.len;
2721        if (size_only) {
2722                s->data = NULL;
2723                strbuf_release(&buf);
2724        } else {
2725                s->data = strbuf_detach(&buf, NULL);
2726                s->should_free = 1;
2727        }
2728        return 0;
2729}
2730
2731/*
2732 * While doing rename detection and pickaxe operation, we may need to
2733 * grab the data for the blob (or file) for our own in-core comparison.
2734 * diff_filespec has data and size fields for this purpose.
2735 */
2736int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
2737{
2738        int size_only = flags & CHECK_SIZE_ONLY;
2739        int err = 0;
2740        /*
2741         * demote FAIL to WARN to allow inspecting the situation
2742         * instead of refusing.
2743         */
2744        enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
2745                                    ? SAFE_CRLF_WARN
2746                                    : safe_crlf);
2747
2748        if (!DIFF_FILE_VALID(s))
2749                die("internal error: asking to populate invalid file.");
2750        if (S_ISDIR(s->mode))
2751                return -1;
2752
2753        if (s->data)
2754                return 0;
2755
2756        if (size_only && 0 < s->size)
2757                return 0;
2758
2759        if (S_ISGITLINK(s->mode))
2760                return diff_populate_gitlink(s, size_only);
2761
2762        if (!s->sha1_valid ||
2763            reuse_worktree_file(s->path, s->sha1, 0)) {
2764                struct strbuf buf = STRBUF_INIT;
2765                struct stat st;
2766                int fd;
2767
2768                if (lstat(s->path, &st) < 0) {
2769                        if (errno == ENOENT) {
2770                        err_empty:
2771                                err = -1;
2772                        empty:
2773                                s->data = (char *)"";
2774                                s->size = 0;
2775                                return err;
2776                        }
2777                }
2778                s->size = xsize_t(st.st_size);
2779                if (!s->size)
2780                        goto empty;
2781                if (S_ISLNK(st.st_mode)) {
2782                        struct strbuf sb = STRBUF_INIT;
2783
2784                        if (strbuf_readlink(&sb, s->path, s->size))
2785                                goto err_empty;
2786                        s->size = sb.len;
2787                        s->data = strbuf_detach(&sb, NULL);
2788                        s->should_free = 1;
2789                        return 0;
2790                }
2791                if (size_only)
2792                        return 0;
2793                if ((flags & CHECK_BINARY) &&
2794                    s->size > big_file_threshold && s->is_binary == -1) {
2795                        s->is_binary = 1;
2796                        return 0;
2797                }
2798                fd = open(s->path, O_RDONLY);
2799                if (fd < 0)
2800                        goto err_empty;
2801                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2802                close(fd);
2803                s->should_munmap = 1;
2804
2805                /*
2806                 * Convert from working tree format to canonical git format
2807                 */
2808                if (convert_to_git(s->path, s->data, s->size, &buf, crlf_warn)) {
2809                        size_t size = 0;
2810                        munmap(s->data, s->size);
2811                        s->should_munmap = 0;
2812                        s->data = strbuf_detach(&buf, &size);
2813                        s->size = size;
2814                        s->should_free = 1;
2815                }
2816        }
2817        else {
2818                enum object_type type;
2819                if (size_only || (flags & CHECK_BINARY)) {
2820                        type = sha1_object_info(s->sha1, &s->size);
2821                        if (type < 0)
2822                                die("unable to read %s", sha1_to_hex(s->sha1));
2823                        if (size_only)
2824                                return 0;
2825                        if (s->size > big_file_threshold && s->is_binary == -1) {
2826                                s->is_binary = 1;
2827                                return 0;
2828                        }
2829                }
2830                s->data = read_sha1_file(s->sha1, &type, &s->size);
2831                if (!s->data)
2832                        die("unable to read %s", sha1_to_hex(s->sha1));
2833                s->should_free = 1;
2834        }
2835        return 0;
2836}
2837
2838void diff_free_filespec_blob(struct diff_filespec *s)
2839{
2840        if (s->should_free)
2841                free(s->data);
2842        else if (s->should_munmap)
2843                munmap(s->data, s->size);
2844
2845        if (s->should_free || s->should_munmap) {
2846                s->should_free = s->should_munmap = 0;
2847                s->data = NULL;
2848        }
2849}
2850
2851void diff_free_filespec_data(struct diff_filespec *s)
2852{
2853        diff_free_filespec_blob(s);
2854        free(s->cnt_data);
2855        s->cnt_data = NULL;
2856}
2857
2858static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2859                           void *blob,
2860                           unsigned long size,
2861                           const unsigned char *sha1,
2862                           int mode)
2863{
2864        int fd;
2865        struct strbuf buf = STRBUF_INIT;
2866        struct strbuf template = STRBUF_INIT;
2867        char *path_dup = xstrdup(path);
2868        const char *base = basename(path_dup);
2869
2870        /* Generate "XXXXXX_basename.ext" */
2871        strbuf_addstr(&template, "XXXXXX_");
2872        strbuf_addstr(&template, base);
2873
2874        fd = mks_tempfile_ts(&temp->tempfile, template.buf, strlen(base) + 1);
2875        if (fd < 0)
2876                die_errno("unable to create temp-file");
2877        if (convert_to_working_tree(path,
2878                        (const char *)blob, (size_t)size, &buf)) {
2879                blob = buf.buf;
2880                size = buf.len;
2881        }
2882        if (write_in_full(fd, blob, size) != size)
2883                die_errno("unable to write temp-file");
2884        close_tempfile(&temp->tempfile);
2885        temp->name = get_tempfile_path(&temp->tempfile);
2886        sha1_to_hex_r(temp->hex, sha1);
2887        xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
2888        strbuf_release(&buf);
2889        strbuf_release(&template);
2890        free(path_dup);
2891}
2892
2893static struct diff_tempfile *prepare_temp_file(const char *name,
2894                struct diff_filespec *one)
2895{
2896        struct diff_tempfile *temp = claim_diff_tempfile();
2897
2898        if (!DIFF_FILE_VALID(one)) {
2899        not_a_valid_file:
2900                /* A '-' entry produces this for file-2, and
2901                 * a '+' entry produces this for file-1.
2902                 */
2903                temp->name = "/dev/null";
2904                xsnprintf(temp->hex, sizeof(temp->hex), ".");
2905                xsnprintf(temp->mode, sizeof(temp->mode), ".");
2906                return temp;
2907        }
2908
2909        if (!S_ISGITLINK(one->mode) &&
2910            (!one->sha1_valid ||
2911             reuse_worktree_file(name, one->sha1, 1))) {
2912                struct stat st;
2913                if (lstat(name, &st) < 0) {
2914                        if (errno == ENOENT)
2915                                goto not_a_valid_file;
2916                        die_errno("stat(%s)", name);
2917                }
2918                if (S_ISLNK(st.st_mode)) {
2919                        struct strbuf sb = STRBUF_INIT;
2920                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
2921                                die_errno("readlink(%s)", name);
2922                        prep_temp_blob(name, temp, sb.buf, sb.len,
2923                                       (one->sha1_valid ?
2924                                        one->sha1 : null_sha1),
2925                                       (one->sha1_valid ?
2926                                        one->mode : S_IFLNK));
2927                        strbuf_release(&sb);
2928                }
2929                else {
2930                        /* we can borrow from the file in the work tree */
2931                        temp->name = name;
2932                        if (!one->sha1_valid)
2933                                sha1_to_hex_r(temp->hex, null_sha1);
2934                        else
2935                                sha1_to_hex_r(temp->hex, one->sha1);
2936                        /* Even though we may sometimes borrow the
2937                         * contents from the work tree, we always want
2938                         * one->mode.  mode is trustworthy even when
2939                         * !(one->sha1_valid), as long as
2940                         * DIFF_FILE_VALID(one).
2941                         */
2942                        xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
2943                }
2944                return temp;
2945        }
2946        else {
2947                if (diff_populate_filespec(one, 0))
2948                        die("cannot read data blob for %s", one->path);
2949                prep_temp_blob(name, temp, one->data, one->size,
2950                               one->sha1, one->mode);
2951        }
2952        return temp;
2953}
2954
2955static void add_external_diff_name(struct argv_array *argv,
2956                                   const char *name,
2957                                   struct diff_filespec *df)
2958{
2959        struct diff_tempfile *temp = prepare_temp_file(name, df);
2960        argv_array_push(argv, temp->name);
2961        argv_array_push(argv, temp->hex);
2962        argv_array_push(argv, temp->mode);
2963}
2964
2965/* An external diff command takes:
2966 *
2967 * diff-cmd name infile1 infile1-sha1 infile1-mode \
2968 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2969 *
2970 */
2971static void run_external_diff(const char *pgm,
2972                              const char *name,
2973                              const char *other,
2974                              struct diff_filespec *one,
2975                              struct diff_filespec *two,
2976                              const char *xfrm_msg,
2977                              int complete_rewrite,
2978                              struct diff_options *o)
2979{
2980        struct argv_array argv = ARGV_ARRAY_INIT;
2981        struct argv_array env = ARGV_ARRAY_INIT;
2982        struct diff_queue_struct *q = &diff_queued_diff;
2983
2984        argv_array_push(&argv, pgm);
2985        argv_array_push(&argv, name);
2986
2987        if (one && two) {
2988                add_external_diff_name(&argv, name, one);
2989                if (!other)
2990                        add_external_diff_name(&argv, name, two);
2991                else {
2992                        add_external_diff_name(&argv, other, two);
2993                        argv_array_push(&argv, other);
2994                        argv_array_push(&argv, xfrm_msg);
2995                }
2996        }
2997
2998        argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
2999        argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
3000
3001        if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
3002                die(_("external diff died, stopping at %s"), name);
3003
3004        remove_tempfile();
3005        argv_array_clear(&argv);
3006        argv_array_clear(&env);
3007}
3008
3009static int similarity_index(struct diff_filepair *p)
3010{
3011        return p->score * 100 / MAX_SCORE;
3012}
3013
3014static void fill_metainfo(struct strbuf *msg,
3015                          const char *name,
3016                          const char *other,
3017                          struct diff_filespec *one,
3018                          struct diff_filespec *two,
3019                          struct diff_options *o,
3020                          struct diff_filepair *p,
3021                          int *must_show_header,
3022                          int use_color)
3023{
3024        const char *set = diff_get_color(use_color, DIFF_METAINFO);
3025        const char *reset = diff_get_color(use_color, DIFF_RESET);
3026        const char *line_prefix = diff_line_prefix(o);
3027
3028        *must_show_header = 1;
3029        strbuf_init(msg, PATH_MAX * 2 + 300);
3030        switch (p->status) {
3031        case DIFF_STATUS_COPIED:
3032                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3033                            line_prefix, set, similarity_index(p));
3034                strbuf_addf(msg, "%s\n%s%scopy from ",
3035                            reset,  line_prefix, set);
3036                quote_c_style(name, msg, NULL, 0);
3037                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
3038                quote_c_style(other, msg, NULL, 0);
3039                strbuf_addf(msg, "%s\n", reset);
3040                break;
3041        case DIFF_STATUS_RENAMED:
3042                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3043                            line_prefix, set, similarity_index(p));
3044                strbuf_addf(msg, "%s\n%s%srename from ",
3045                            reset, line_prefix, set);
3046                quote_c_style(name, msg, NULL, 0);
3047                strbuf_addf(msg, "%s\n%s%srename to ",
3048                            reset, line_prefix, set);
3049                quote_c_style(other, msg, NULL, 0);
3050                strbuf_addf(msg, "%s\n", reset);
3051                break;
3052        case DIFF_STATUS_MODIFIED:
3053                if (p->score) {
3054                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3055                                    line_prefix,
3056                                    set, similarity_index(p), reset);
3057                        break;
3058                }
3059                /* fallthru */
3060        default:
3061                *must_show_header = 0;
3062        }
3063        if (one && two && hashcmp(one->sha1, two->sha1)) {
3064                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3065
3066                if (DIFF_OPT_TST(o, BINARY)) {
3067                        mmfile_t mf;
3068                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3069                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3070                                abbrev = 40;
3071                }
3072                strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
3073                            find_unique_abbrev(one->sha1, abbrev));
3074                strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
3075                if (one->mode == two->mode)
3076                        strbuf_addf(msg, " %06o", one->mode);
3077                strbuf_addf(msg, "%s\n", reset);
3078        }
3079}
3080
3081static void run_diff_cmd(const char *pgm,
3082                         const char *name,
3083                         const char *other,
3084                         const char *attr_path,
3085                         struct diff_filespec *one,
3086                         struct diff_filespec *two,
3087                         struct strbuf *msg,
3088                         struct diff_options *o,
3089                         struct diff_filepair *p)
3090{
3091        const char *xfrm_msg = NULL;
3092        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3093        int must_show_header = 0;
3094
3095
3096        if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3097                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3098                if (drv && drv->external)
3099                        pgm = drv->external;
3100        }
3101
3102        if (msg) {
3103                /*
3104                 * don't use colors when the header is intended for an
3105                 * external diff driver
3106                 */
3107                fill_metainfo(msg, name, other, one, two, o, p,
3108                              &must_show_header,
3109                              want_color(o->use_color) && !pgm);
3110                xfrm_msg = msg->len ? msg->buf : NULL;
3111        }
3112
3113        if (pgm) {
3114                run_external_diff(pgm, name, other, one, two, xfrm_msg,
3115                                  complete_rewrite, o);
3116                return;
3117        }
3118        if (one && two)
3119                builtin_diff(name, other ? other : name,
3120                             one, two, xfrm_msg, must_show_header,
3121                             o, complete_rewrite);
3122        else
3123                fprintf(o->file, "* Unmerged path %s\n", name);
3124}
3125
3126static void diff_fill_sha1_info(struct diff_filespec *one)
3127{
3128        if (DIFF_FILE_VALID(one)) {
3129                if (!one->sha1_valid) {
3130                        struct stat st;
3131                        if (one->is_stdin) {
3132                                hashcpy(one->sha1, null_sha1);
3133                                return;
3134                        }
3135                        if (lstat(one->path, &st) < 0)
3136                                die_errno("stat '%s'", one->path);
3137                        if (index_path(one->sha1, one->path, &st, 0))
3138                                die("cannot hash %s", one->path);
3139                }
3140        }
3141        else
3142                hashclr(one->sha1);
3143}
3144
3145static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3146{
3147        /* Strip the prefix but do not molest /dev/null and absolute paths */
3148        if (*namep && **namep != '/') {
3149                *namep += prefix_length;
3150                if (**namep == '/')
3151                        ++*namep;
3152        }
3153        if (*otherp && **otherp != '/') {
3154                *otherp += prefix_length;
3155                if (**otherp == '/')
3156                        ++*otherp;
3157        }
3158}
3159
3160static void run_diff(struct diff_filepair *p, struct diff_options *o)
3161{
3162        const char *pgm = external_diff();
3163        struct strbuf msg;
3164        struct diff_filespec *one = p->one;
3165        struct diff_filespec *two = p->two;
3166        const char *name;
3167        const char *other;
3168        const char *attr_path;
3169
3170        name  = p->one->path;
3171        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3172        attr_path = name;
3173        if (o->prefix_length)
3174                strip_prefix(o->prefix_length, &name, &other);
3175
3176        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3177                pgm = NULL;
3178
3179        if (DIFF_PAIR_UNMERGED(p)) {
3180                run_diff_cmd(pgm, name, NULL, attr_path,
3181                             NULL, NULL, NULL, o, p);
3182                return;
3183        }
3184
3185        diff_fill_sha1_info(one);
3186        diff_fill_sha1_info(two);
3187
3188        if (!pgm &&
3189            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3190            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3191                /*
3192                 * a filepair that changes between file and symlink
3193                 * needs to be split into deletion and creation.
3194                 */
3195                struct diff_filespec *null = alloc_filespec(two->path);
3196                run_diff_cmd(NULL, name, other, attr_path,
3197                             one, null, &msg, o, p);
3198                free(null);
3199                strbuf_release(&msg);
3200
3201                null = alloc_filespec(one->path);
3202                run_diff_cmd(NULL, name, other, attr_path,
3203                             null, two, &msg, o, p);
3204                free(null);
3205        }
3206        else
3207                run_diff_cmd(pgm, name, other, attr_path,
3208                             one, two, &msg, o, p);
3209
3210        strbuf_release(&msg);
3211}
3212
3213static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3214                         struct diffstat_t *diffstat)
3215{
3216        const char *name;
3217        const char *other;
3218
3219        if (DIFF_PAIR_UNMERGED(p)) {
3220                /* unmerged */
3221                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3222                return;
3223        }
3224
3225        name = p->one->path;
3226        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3227
3228        if (o->prefix_length)
3229                strip_prefix(o->prefix_length, &name, &other);
3230
3231        diff_fill_sha1_info(p->one);
3232        diff_fill_sha1_info(p->two);
3233
3234        builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3235}
3236
3237static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3238{
3239        const char *name;
3240        const char *other;
3241        const char *attr_path;
3242
3243        if (DIFF_PAIR_UNMERGED(p)) {
3244                /* unmerged */
3245                return;
3246        }
3247
3248        name = p->one->path;
3249        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3250        attr_path = other ? other : name;
3251
3252        if (o->prefix_length)
3253                strip_prefix(o->prefix_length, &name, &other);
3254
3255        diff_fill_sha1_info(p->one);
3256        diff_fill_sha1_info(p->two);
3257
3258        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3259}
3260
3261void diff_setup(struct diff_options *options)
3262{
3263        memcpy(options, &default_diff_options, sizeof(*options));
3264
3265        options->file = stdout;
3266
3267        options->line_termination = '\n';
3268        options->break_opt = -1;
3269        options->rename_limit = -1;
3270        options->dirstat_permille = diff_dirstat_permille_default;
3271        options->context = diff_context_default;
3272        options->ws_error_highlight = WSEH_NEW;
3273        DIFF_OPT_SET(options, RENAME_EMPTY);
3274
3275        /* pathchange left =NULL by default */
3276        options->change = diff_change;
3277        options->add_remove = diff_addremove;
3278        options->use_color = diff_use_color_default;
3279        options->detect_rename = diff_detect_rename_default;
3280        options->xdl_opts |= diff_algorithm;
3281
3282        options->orderfile = diff_order_file_cfg;
3283
3284        if (diff_no_prefix) {
3285                options->a_prefix = options->b_prefix = "";
3286        } else if (!diff_mnemonic_prefix) {
3287                options->a_prefix = "a/";
3288                options->b_prefix = "b/";
3289        }
3290}
3291
3292void diff_setup_done(struct diff_options *options)
3293{
3294        int count = 0;
3295
3296        if (options->set_default)
3297                options->set_default(options);
3298
3299        if (options->output_format & DIFF_FORMAT_NAME)
3300                count++;
3301        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3302                count++;
3303        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3304                count++;
3305        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3306                count++;
3307        if (count > 1)
3308                die("--name-only, --name-status, --check and -s are mutually exclusive");
3309
3310        /*
3311         * Most of the time we can say "there are changes"
3312         * only by checking if there are changed paths, but
3313         * --ignore-whitespace* options force us to look
3314         * inside contents.
3315         */
3316
3317        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3318            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3319            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3320                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3321        else
3322                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3323
3324        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3325                options->detect_rename = DIFF_DETECT_COPY;
3326
3327        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3328                options->prefix = NULL;
3329        if (options->prefix)
3330                options->prefix_length = strlen(options->prefix);
3331        else
3332                options->prefix_length = 0;
3333
3334        if (options->output_format & (DIFF_FORMAT_NAME |
3335                                      DIFF_FORMAT_NAME_STATUS |
3336                                      DIFF_FORMAT_CHECKDIFF |
3337                                      DIFF_FORMAT_NO_OUTPUT))
3338                options->output_format &= ~(DIFF_FORMAT_RAW |
3339                                            DIFF_FORMAT_NUMSTAT |
3340                                            DIFF_FORMAT_DIFFSTAT |
3341                                            DIFF_FORMAT_SHORTSTAT |
3342                                            DIFF_FORMAT_DIRSTAT |
3343                                            DIFF_FORMAT_SUMMARY |
3344                                            DIFF_FORMAT_PATCH);
3345
3346        /*
3347         * These cases always need recursive; we do not drop caller-supplied
3348         * recursive bits for other formats here.
3349         */
3350        if (options->output_format & (DIFF_FORMAT_PATCH |
3351                                      DIFF_FORMAT_NUMSTAT |
3352                                      DIFF_FORMAT_DIFFSTAT |
3353                                      DIFF_FORMAT_SHORTSTAT |
3354                                      DIFF_FORMAT_DIRSTAT |
3355                                      DIFF_FORMAT_SUMMARY |
3356                                      DIFF_FORMAT_CHECKDIFF))
3357                DIFF_OPT_SET(options, RECURSIVE);
3358        /*
3359         * Also pickaxe would not work very well if you do not say recursive
3360         */
3361        if (options->pickaxe)
3362                DIFF_OPT_SET(options, RECURSIVE);
3363        /*
3364         * When patches are generated, submodules diffed against the work tree
3365         * must be checked for dirtiness too so it can be shown in the output
3366         */
3367        if (options->output_format & DIFF_FORMAT_PATCH)
3368                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3369
3370        if (options->detect_rename && options->rename_limit < 0)
3371                options->rename_limit = diff_rename_limit_default;
3372        if (options->setup & DIFF_SETUP_USE_CACHE) {
3373                if (!active_cache)
3374                        /* read-cache does not die even when it fails
3375                         * so it is safe for us to do this here.  Also
3376                         * it does not smudge active_cache or active_nr
3377                         * when it fails, so we do not have to worry about
3378                         * cleaning it up ourselves either.
3379                         */
3380                        read_cache();
3381        }
3382        if (options->abbrev <= 0 || 40 < options->abbrev)
3383                options->abbrev = 40; /* full */
3384
3385        /*
3386         * It does not make sense to show the first hit we happened
3387         * to have found.  It does not make sense not to return with
3388         * exit code in such a case either.
3389         */
3390        if (DIFF_OPT_TST(options, QUICK)) {
3391                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3392                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3393        }
3394
3395        options->diff_path_counter = 0;
3396
3397        if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
3398                die(_("--follow requires exactly one pathspec"));
3399}
3400
3401static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3402{
3403        char c, *eq;
3404        int len;
3405
3406        if (*arg != '-')
3407                return 0;
3408        c = *++arg;
3409        if (!c)
3410                return 0;
3411        if (c == arg_short) {
3412                c = *++arg;
3413                if (!c)
3414                        return 1;
3415                if (val && isdigit(c)) {
3416                        char *end;
3417                        int n = strtoul(arg, &end, 10);
3418                        if (*end)
3419                                return 0;
3420                        *val = n;
3421                        return 1;
3422                }
3423                return 0;
3424        }
3425        if (c != '-')
3426                return 0;
3427        arg++;
3428        eq = strchrnul(arg, '=');
3429        len = eq - arg;
3430        if (!len || strncmp(arg, arg_long, len))
3431                return 0;
3432        if (*eq) {
3433                int n;
3434                char *end;
3435                if (!isdigit(*++eq))
3436                        return 0;
3437                n = strtoul(eq, &end, 10);
3438                if (*end)
3439                        return 0;
3440                *val = n;
3441        }
3442        return 1;
3443}
3444
3445static int diff_scoreopt_parse(const char *opt);
3446
3447static inline int short_opt(char opt, const char **argv,
3448                            const char **optarg)
3449{
3450        const char *arg = argv[0];
3451        if (arg[0] != '-' || arg[1] != opt)
3452                return 0;
3453        if (arg[2] != '\0') {
3454                *optarg = arg + 2;
3455                return 1;
3456        }
3457        if (!argv[1])
3458                die("Option '%c' requires a value", opt);
3459        *optarg = argv[1];
3460        return 2;
3461}
3462
3463int parse_long_opt(const char *opt, const char **argv,
3464                   const char **optarg)
3465{
3466        const char *arg = argv[0];
3467        if (!skip_prefix(arg, "--", &arg))
3468                return 0;
3469        if (!skip_prefix(arg, opt, &arg))
3470                return 0;
3471        if (*arg == '=') { /* stuck form: --option=value */
3472                *optarg = arg + 1;
3473                return 1;
3474        }
3475        if (*arg != '\0')
3476                return 0;
3477        /* separate form: --option value */
3478        if (!argv[1])
3479                die("Option '--%s' requires a value", opt);
3480        *optarg = argv[1];
3481        return 2;
3482}
3483
3484static int stat_opt(struct diff_options *options, const char **av)
3485{
3486        const char *arg = av[0];
3487        char *end;
3488        int width = options->stat_width;
3489        int name_width = options->stat_name_width;
3490        int graph_width = options->stat_graph_width;
3491        int count = options->stat_count;
3492        int argcount = 1;
3493
3494        if (!skip_prefix(arg, "--stat", &arg))
3495                die("BUG: stat option does not begin with --stat: %s", arg);
3496        end = (char *)arg;
3497
3498        switch (*arg) {
3499        case '-':
3500                if (skip_prefix(arg, "-width", &arg)) {
3501                        if (*arg == '=')
3502                                width = strtoul(arg + 1, &end, 10);
3503                        else if (!*arg && !av[1])
3504                                die("Option '--stat-width' requires a value");
3505                        else if (!*arg) {
3506                                width = strtoul(av[1], &end, 10);
3507                                argcount = 2;
3508                        }
3509                } else if (skip_prefix(arg, "-name-width", &arg)) {
3510                        if (*arg == '=')
3511                                name_width = strtoul(arg + 1, &end, 10);
3512                        else if (!*arg && !av[1])
3513                                die("Option '--stat-name-width' requires a value");
3514                        else if (!*arg) {
3515                                name_width = strtoul(av[1], &end, 10);
3516                                argcount = 2;
3517                        }
3518                } else if (skip_prefix(arg, "-graph-width", &arg)) {
3519                        if (*arg == '=')
3520                                graph_width = strtoul(arg + 1, &end, 10);
3521                        else if (!*arg && !av[1])
3522                                die("Option '--stat-graph-width' requires a value");
3523                        else if (!*arg) {
3524                                graph_width = strtoul(av[1], &end, 10);
3525                                argcount = 2;
3526                        }
3527                } else if (skip_prefix(arg, "-count", &arg)) {
3528                        if (*arg == '=')
3529                                count = strtoul(arg + 1, &end, 10);
3530                        else if (!*arg && !av[1])
3531                                die("Option '--stat-count' requires a value");
3532                        else if (!*arg) {
3533                                count = strtoul(av[1], &end, 10);
3534                                argcount = 2;
3535                        }
3536                }
3537                break;
3538        case '=':
3539                width = strtoul(arg+1, &end, 10);
3540                if (*end == ',')
3541                        name_width = strtoul(end+1, &end, 10);
3542                if (*end == ',')
3543                        count = strtoul(end+1, &end, 10);
3544        }
3545
3546        /* Important! This checks all the error cases! */
3547        if (*end)
3548                return 0;
3549        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3550        options->stat_name_width = name_width;
3551        options->stat_graph_width = graph_width;
3552        options->stat_width = width;
3553        options->stat_count = count;
3554        return argcount;
3555}
3556
3557static int parse_dirstat_opt(struct diff_options *options, const char *params)
3558{
3559        struct strbuf errmsg = STRBUF_INIT;
3560        if (parse_dirstat_params(options, params, &errmsg))
3561                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3562                    errmsg.buf);
3563        strbuf_release(&errmsg);
3564        /*
3565         * The caller knows a dirstat-related option is given from the command
3566         * line; allow it to say "return this_function();"
3567         */
3568        options->output_format |= DIFF_FORMAT_DIRSTAT;
3569        return 1;
3570}
3571
3572static int parse_submodule_opt(struct diff_options *options, const char *value)
3573{
3574        if (parse_submodule_params(options, value))
3575                die(_("Failed to parse --submodule option parameter: '%s'"),
3576                        value);
3577        return 1;
3578}
3579
3580static const char diff_status_letters[] = {
3581        DIFF_STATUS_ADDED,
3582        DIFF_STATUS_COPIED,
3583        DIFF_STATUS_DELETED,
3584        DIFF_STATUS_MODIFIED,
3585        DIFF_STATUS_RENAMED,
3586        DIFF_STATUS_TYPE_CHANGED,
3587        DIFF_STATUS_UNKNOWN,
3588        DIFF_STATUS_UNMERGED,
3589        DIFF_STATUS_FILTER_AON,
3590        DIFF_STATUS_FILTER_BROKEN,
3591        '\0',
3592};
3593
3594static unsigned int filter_bit['Z' + 1];
3595
3596static void prepare_filter_bits(void)
3597{
3598        int i;
3599
3600        if (!filter_bit[DIFF_STATUS_ADDED]) {
3601                for (i = 0; diff_status_letters[i]; i++)
3602                        filter_bit[(int) diff_status_letters[i]] = (1 << i);
3603        }
3604}
3605
3606static unsigned filter_bit_tst(char status, const struct diff_options *opt)
3607{
3608        return opt->filter & filter_bit[(int) status];
3609}
3610
3611static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
3612{
3613        int i, optch;
3614
3615        prepare_filter_bits();
3616
3617        /*
3618         * If there is a negation e.g. 'd' in the input, and we haven't
3619         * initialized the filter field with another --diff-filter, start
3620         * from full set of bits, except for AON.
3621         */
3622        if (!opt->filter) {
3623                for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3624                        if (optch < 'a' || 'z' < optch)
3625                                continue;
3626                        opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
3627                        opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
3628                        break;
3629                }
3630        }
3631
3632        for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3633                unsigned int bit;
3634                int negate;
3635
3636                if ('a' <= optch && optch <= 'z') {
3637                        negate = 1;
3638                        optch = toupper(optch);
3639                } else {
3640                        negate = 0;
3641                }
3642
3643                bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
3644                if (!bit)
3645                        return optarg[i];
3646                if (negate)
3647                        opt->filter &= ~bit;
3648                else
3649                        opt->filter |= bit;
3650        }
3651        return 0;
3652}
3653
3654static void enable_patch_output(int *fmt) {
3655        *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
3656        *fmt |= DIFF_FORMAT_PATCH;
3657}
3658
3659static int parse_one_token(const char **arg, const char *token)
3660{
3661        const char *rest;
3662        if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
3663                *arg = rest;
3664                return 1;
3665        }
3666        return 0;
3667}
3668
3669static int parse_ws_error_highlight(struct diff_options *opt, const char *arg)
3670{
3671        const char *orig_arg = arg;
3672        unsigned val = 0;
3673        while (*arg) {
3674                if (parse_one_token(&arg, "none"))
3675                        val = 0;
3676                else if (parse_one_token(&arg, "default"))
3677                        val = WSEH_NEW;
3678                else if (parse_one_token(&arg, "all"))
3679                        val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
3680                else if (parse_one_token(&arg, "new"))
3681                        val |= WSEH_NEW;
3682                else if (parse_one_token(&arg, "old"))
3683                        val |= WSEH_OLD;
3684                else if (parse_one_token(&arg, "context"))
3685                        val |= WSEH_CONTEXT;
3686                else {
3687                        error("unknown value after ws-error-highlight=%.*s",
3688                              (int)(arg - orig_arg), orig_arg);
3689                        return 0;
3690                }
3691                if (*arg)
3692                        arg++;
3693        }
3694        opt->ws_error_highlight = val;
3695        return 1;
3696}
3697
3698int diff_opt_parse(struct diff_options *options,
3699                   const char **av, int ac, const char *prefix)
3700{
3701        const char *arg = av[0];
3702        const char *optarg;
3703        int argcount;
3704
3705        if (!prefix)
3706                prefix = "";
3707
3708        /* Output format options */
3709        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
3710            || opt_arg(arg, 'U', "unified", &options->context))
3711                enable_patch_output(&options->output_format);
3712        else if (!strcmp(arg, "--raw"))
3713                options->output_format |= DIFF_FORMAT_RAW;
3714        else if (!strcmp(arg, "--patch-with-raw")) {
3715                enable_patch_output(&options->output_format);
3716                options->output_format |= DIFF_FORMAT_RAW;
3717        } else if (!strcmp(arg, "--numstat"))
3718                options->output_format |= DIFF_FORMAT_NUMSTAT;
3719        else if (!strcmp(arg, "--shortstat"))
3720                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3721        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3722                return parse_dirstat_opt(options, "");
3723        else if (skip_prefix(arg, "-X", &arg))
3724                return parse_dirstat_opt(options, arg);
3725        else if (skip_prefix(arg, "--dirstat=", &arg))
3726                return parse_dirstat_opt(options, arg);
3727        else if (!strcmp(arg, "--cumulative"))
3728                return parse_dirstat_opt(options, "cumulative");
3729        else if (!strcmp(arg, "--dirstat-by-file"))
3730                return parse_dirstat_opt(options, "files");
3731        else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
3732                parse_dirstat_opt(options, "files");
3733                return parse_dirstat_opt(options, arg);
3734        }
3735        else if (!strcmp(arg, "--check"))
3736                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3737        else if (!strcmp(arg, "--summary"))
3738                options->output_format |= DIFF_FORMAT_SUMMARY;
3739        else if (!strcmp(arg, "--patch-with-stat")) {
3740                enable_patch_output(&options->output_format);
3741                options->output_format |= DIFF_FORMAT_DIFFSTAT;
3742        } else if (!strcmp(arg, "--name-only"))
3743                options->output_format |= DIFF_FORMAT_NAME;
3744        else if (!strcmp(arg, "--name-status"))
3745                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3746        else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
3747                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3748        else if (starts_with(arg, "--stat"))
3749                /* --stat, --stat-width, --stat-name-width, or --stat-count */
3750                return stat_opt(options, av);
3751
3752        /* renames options */
3753        else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
3754                 !strcmp(arg, "--break-rewrites")) {
3755                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3756                        return error("invalid argument to -B: %s", arg+2);
3757        }
3758        else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
3759                 !strcmp(arg, "--find-renames")) {
3760                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3761                        return error("invalid argument to -M: %s", arg+2);
3762                options->detect_rename = DIFF_DETECT_RENAME;
3763        }
3764        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3765                options->irreversible_delete = 1;
3766        }
3767        else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
3768                 !strcmp(arg, "--find-copies")) {
3769                if (options->detect_rename == DIFF_DETECT_COPY)
3770                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3771                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3772                        return error("invalid argument to -C: %s", arg+2);
3773                options->detect_rename = DIFF_DETECT_COPY;
3774        }
3775        else if (!strcmp(arg, "--no-renames"))
3776                options->detect_rename = 0;
3777        else if (!strcmp(arg, "--rename-empty"))
3778                DIFF_OPT_SET(options, RENAME_EMPTY);
3779        else if (!strcmp(arg, "--no-rename-empty"))
3780                DIFF_OPT_CLR(options, RENAME_EMPTY);
3781        else if (!strcmp(arg, "--relative"))
3782                DIFF_OPT_SET(options, RELATIVE_NAME);
3783        else if (skip_prefix(arg, "--relative=", &arg)) {
3784                DIFF_OPT_SET(options, RELATIVE_NAME);
3785                options->prefix = arg;
3786        }
3787
3788        /* xdiff options */
3789        else if (!strcmp(arg, "--minimal"))
3790                DIFF_XDL_SET(options, NEED_MINIMAL);
3791        else if (!strcmp(arg, "--no-minimal"))
3792                DIFF_XDL_CLR(options, NEED_MINIMAL);
3793        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3794                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3795        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3796                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3797        else if (!strcmp(arg, "--ignore-space-at-eol"))
3798                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3799        else if (!strcmp(arg, "--ignore-blank-lines"))
3800                DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
3801        else if (!strcmp(arg, "--patience"))
3802                options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3803        else if (!strcmp(arg, "--histogram"))
3804                options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3805        else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
3806                long value = parse_algorithm_value(optarg);
3807                if (value < 0)
3808                        return error("option diff-algorithm accepts \"myers\", "
3809                                     "\"minimal\", \"patience\" and \"histogram\"");
3810                /* clear out previous settings */
3811                DIFF_XDL_CLR(options, NEED_MINIMAL);
3812                options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3813                options->xdl_opts |= value;
3814                return argcount;
3815        }
3816
3817        /* flags options */
3818        else if (!strcmp(arg, "--binary")) {
3819                enable_patch_output(&options->output_format);
3820                DIFF_OPT_SET(options, BINARY);
3821        }
3822        else if (!strcmp(arg, "--full-index"))
3823                DIFF_OPT_SET(options, FULL_INDEX);
3824        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3825                DIFF_OPT_SET(options, TEXT);
3826        else if (!strcmp(arg, "-R"))
3827                DIFF_OPT_SET(options, REVERSE_DIFF);
3828        else if (!strcmp(arg, "--find-copies-harder"))
3829                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3830        else if (!strcmp(arg, "--follow"))
3831                DIFF_OPT_SET(options, FOLLOW_RENAMES);
3832        else if (!strcmp(arg, "--no-follow")) {
3833                DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3834                DIFF_OPT_CLR(options, DEFAULT_FOLLOW_RENAMES);
3835        } else if (!strcmp(arg, "--color"))
3836                options->use_color = 1;
3837        else if (skip_prefix(arg, "--color=", &arg)) {
3838                int value = git_config_colorbool(NULL, arg);
3839                if (value < 0)
3840                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
3841                options->use_color = value;
3842        }
3843        else if (!strcmp(arg, "--no-color"))
3844                options->use_color = 0;
3845        else if (!strcmp(arg, "--color-words")) {
3846                options->use_color = 1;
3847                options->word_diff = DIFF_WORDS_COLOR;
3848        }
3849        else if (skip_prefix(arg, "--color-words=", &arg)) {
3850                options->use_color = 1;
3851                options->word_diff = DIFF_WORDS_COLOR;
3852                options->word_regex = arg;
3853        }
3854        else if (!strcmp(arg, "--word-diff")) {
3855                if (options->word_diff == DIFF_WORDS_NONE)
3856                        options->word_diff = DIFF_WORDS_PLAIN;
3857        }
3858        else if (skip_prefix(arg, "--word-diff=", &arg)) {
3859                if (!strcmp(arg, "plain"))
3860                        options->word_diff = DIFF_WORDS_PLAIN;
3861                else if (!strcmp(arg, "color")) {
3862                        options->use_color = 1;
3863                        options->word_diff = DIFF_WORDS_COLOR;
3864                }
3865                else if (!strcmp(arg, "porcelain"))
3866                        options->word_diff = DIFF_WORDS_PORCELAIN;
3867                else if (!strcmp(arg, "none"))
3868                        options->word_diff = DIFF_WORDS_NONE;
3869                else
3870                        die("bad --word-diff argument: %s", arg);
3871        }
3872        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3873                if (options->word_diff == DIFF_WORDS_NONE)
3874                        options->word_diff = DIFF_WORDS_PLAIN;
3875                options->word_regex = optarg;
3876                return argcount;
3877        }
3878        else if (!strcmp(arg, "--exit-code"))
3879                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3880        else if (!strcmp(arg, "--quiet"))
3881                DIFF_OPT_SET(options, QUICK);
3882        else if (!strcmp(arg, "--ext-diff"))
3883                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3884        else if (!strcmp(arg, "--no-ext-diff"))
3885                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3886        else if (!strcmp(arg, "--textconv"))
3887                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3888        else if (!strcmp(arg, "--no-textconv"))
3889                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3890        else if (!strcmp(arg, "--ignore-submodules")) {
3891                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3892                handle_ignore_submodules_arg(options, "all");
3893        } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
3894                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3895                handle_ignore_submodules_arg(options, arg);
3896        } else if (!strcmp(arg, "--submodule"))
3897                DIFF_OPT_SET(options, SUBMODULE_LOG);
3898        else if (skip_prefix(arg, "--submodule=", &arg))
3899                return parse_submodule_opt(options, arg);
3900        else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
3901                return parse_ws_error_highlight(options, arg);
3902
3903        /* misc options */
3904        else if (!strcmp(arg, "-z"))
3905                options->line_termination = 0;
3906        else if ((argcount = short_opt('l', av, &optarg))) {
3907                options->rename_limit = strtoul(optarg, NULL, 10);
3908                return argcount;
3909        }
3910        else if ((argcount = short_opt('S', av, &optarg))) {
3911                options->pickaxe = optarg;
3912                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3913                return argcount;
3914        } else if ((argcount = short_opt('G', av, &optarg))) {
3915                options->pickaxe = optarg;
3916                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3917                return argcount;
3918        }
3919        else if (!strcmp(arg, "--pickaxe-all"))
3920                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3921        else if (!strcmp(arg, "--pickaxe-regex"))
3922                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3923        else if ((argcount = short_opt('O', av, &optarg))) {
3924                const char *path = prefix_filename(prefix, strlen(prefix), optarg);
3925                options->orderfile = xstrdup(path);
3926                return argcount;
3927        }
3928        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3929                int offending = parse_diff_filter_opt(optarg, options);
3930                if (offending)
3931                        die("unknown change class '%c' in --diff-filter=%s",
3932                            offending, optarg);
3933                return argcount;
3934        }
3935        else if (!strcmp(arg, "--abbrev"))
3936                options->abbrev = DEFAULT_ABBREV;
3937        else if (skip_prefix(arg, "--abbrev=", &arg)) {
3938                options->abbrev = strtoul(arg, NULL, 10);
3939                if (options->abbrev < MINIMUM_ABBREV)
3940                        options->abbrev = MINIMUM_ABBREV;
3941                else if (40 < options->abbrev)
3942                        options->abbrev = 40;
3943        }
3944        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3945                options->a_prefix = optarg;
3946                return argcount;
3947        }
3948        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3949                options->b_prefix = optarg;
3950                return argcount;
3951        }
3952        else if (!strcmp(arg, "--no-prefix"))
3953                options->a_prefix = options->b_prefix = "";
3954        else if (opt_arg(arg, '\0', "inter-hunk-context",
3955                         &options->interhunkcontext))
3956                ;
3957        else if (!strcmp(arg, "-W"))
3958                DIFF_OPT_SET(options, FUNCCONTEXT);
3959        else if (!strcmp(arg, "--function-context"))
3960                DIFF_OPT_SET(options, FUNCCONTEXT);
3961        else if (!strcmp(arg, "--no-function-context"))
3962                DIFF_OPT_CLR(options, FUNCCONTEXT);
3963        else if ((argcount = parse_long_opt("output", av, &optarg))) {
3964                const char *path = prefix_filename(prefix, strlen(prefix), optarg);
3965                options->file = fopen(path, "w");
3966                if (!options->file)
3967                        die_errno("Could not open '%s'", path);
3968                options->close_file = 1;
3969                return argcount;
3970        } else
3971                return 0;
3972        return 1;
3973}
3974
3975int parse_rename_score(const char **cp_p)
3976{
3977        unsigned long num, scale;
3978        int ch, dot;
3979        const char *cp = *cp_p;
3980
3981        num = 0;
3982        scale = 1;
3983        dot = 0;
3984        for (;;) {
3985                ch = *cp;
3986                if ( !dot && ch == '.' ) {
3987                        scale = 1;
3988                        dot = 1;
3989                } else if ( ch == '%' ) {
3990                        scale = dot ? scale*100 : 100;
3991                        cp++;   /* % is always at the end */
3992                        break;
3993                } else if ( ch >= '0' && ch <= '9' ) {
3994                        if ( scale < 100000 ) {
3995                                scale *= 10;
3996                                num = (num*10) + (ch-'0');
3997                        }
3998                } else {
3999                        break;
4000                }
4001                cp++;
4002        }
4003        *cp_p = cp;
4004
4005        /* user says num divided by scale and we say internally that
4006         * is MAX_SCORE * num / scale.
4007         */
4008        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
4009}
4010
4011static int diff_scoreopt_parse(const char *opt)
4012{
4013        int opt1, opt2, cmd;
4014
4015        if (*opt++ != '-')
4016                return -1;
4017        cmd = *opt++;
4018        if (cmd == '-') {
4019                /* convert the long-form arguments into short-form versions */
4020                if (skip_prefix(opt, "break-rewrites", &opt)) {
4021                        if (*opt == 0 || *opt++ == '=')
4022                                cmd = 'B';
4023                } else if (skip_prefix(opt, "find-copies", &opt)) {
4024                        if (*opt == 0 || *opt++ == '=')
4025                                cmd = 'C';
4026                } else if (skip_prefix(opt, "find-renames", &opt)) {
4027                        if (*opt == 0 || *opt++ == '=')
4028                                cmd = 'M';
4029                }
4030        }
4031        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
4032                return -1; /* that is not a -M, -C, or -B option */
4033
4034        opt1 = parse_rename_score(&opt);
4035        if (cmd != 'B')
4036                opt2 = 0;
4037        else {
4038                if (*opt == 0)
4039                        opt2 = 0;
4040                else if (*opt != '/')
4041                        return -1; /* we expect -B80/99 or -B80 */
4042                else {
4043                        opt++;
4044                        opt2 = parse_rename_score(&opt);
4045                }
4046        }
4047        if (*opt != 0)
4048                return -1;
4049        return opt1 | (opt2 << 16);
4050}
4051
4052struct diff_queue_struct diff_queued_diff;
4053
4054void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
4055{
4056        ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
4057        queue->queue[queue->nr++] = dp;
4058}
4059
4060struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
4061                                 struct diff_filespec *one,
4062                                 struct diff_filespec *two)
4063{
4064        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
4065        dp->one = one;
4066        dp->two = two;
4067        if (queue)
4068                diff_q(queue, dp);
4069        return dp;
4070}
4071
4072void diff_free_filepair(struct diff_filepair *p)
4073{
4074        free_filespec(p->one);
4075        free_filespec(p->two);
4076        free(p);
4077}
4078
4079/* This is different from find_unique_abbrev() in that
4080 * it stuffs the result with dots for alignment.
4081 */
4082const char *diff_unique_abbrev(const unsigned char *sha1, int len)
4083{
4084        int abblen;
4085        const char *abbrev;
4086        if (len == 40)
4087                return sha1_to_hex(sha1);
4088
4089        abbrev = find_unique_abbrev(sha1, len);
4090        abblen = strlen(abbrev);
4091        if (abblen < 37) {
4092                static char hex[41];
4093                if (len < abblen && abblen <= len + 2)
4094                        xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
4095                else
4096                        xsnprintf(hex, sizeof(hex), "%s...", abbrev);
4097                return hex;
4098        }
4099        return sha1_to_hex(sha1);
4100}
4101
4102static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4103{
4104        int line_termination = opt->line_termination;
4105        int inter_name_termination = line_termination ? '\t' : '\0';
4106
4107        fprintf(opt->file, "%s", diff_line_prefix(opt));
4108        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4109                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4110                        diff_unique_abbrev(p->one->sha1, opt->abbrev));
4111                fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
4112        }
4113        if (p->score) {
4114                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4115                        inter_name_termination);
4116        } else {
4117                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4118        }
4119
4120        if (p->status == DIFF_STATUS_COPIED ||
4121            p->status == DIFF_STATUS_RENAMED) {
4122                const char *name_a, *name_b;
4123                name_a = p->one->path;
4124                name_b = p->two->path;
4125                strip_prefix(opt->prefix_length, &name_a, &name_b);
4126                write_name_quoted(name_a, opt->file, inter_name_termination);
4127                write_name_quoted(name_b, opt->file, line_termination);
4128        } else {
4129                const char *name_a, *name_b;
4130                name_a = p->one->mode ? p->one->path : p->two->path;
4131                name_b = NULL;
4132                strip_prefix(opt->prefix_length, &name_a, &name_b);
4133                write_name_quoted(name_a, opt->file, line_termination);
4134        }
4135}
4136
4137int diff_unmodified_pair(struct diff_filepair *p)
4138{
4139        /* This function is written stricter than necessary to support
4140         * the currently implemented transformers, but the idea is to
4141         * let transformers to produce diff_filepairs any way they want,
4142         * and filter and clean them up here before producing the output.
4143         */
4144        struct diff_filespec *one = p->one, *two = p->two;
4145
4146        if (DIFF_PAIR_UNMERGED(p))
4147                return 0; /* unmerged is interesting */
4148
4149        /* deletion, addition, mode or type change
4150         * and rename are all interesting.
4151         */
4152        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4153            DIFF_PAIR_MODE_CHANGED(p) ||
4154            strcmp(one->path, two->path))
4155                return 0;
4156
4157        /* both are valid and point at the same path.  that is, we are
4158         * dealing with a change.
4159         */
4160        if (one->sha1_valid && two->sha1_valid &&
4161            !hashcmp(one->sha1, two->sha1) &&
4162            !one->dirty_submodule && !two->dirty_submodule)
4163                return 1; /* no change */
4164        if (!one->sha1_valid && !two->sha1_valid)
4165                return 1; /* both look at the same file on the filesystem. */
4166        return 0;
4167}
4168
4169static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
4170{
4171        if (diff_unmodified_pair(p))
4172                return;
4173
4174        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4175            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4176                return; /* no tree diffs in patch format */
4177
4178        run_diff(p, o);
4179}
4180
4181static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
4182                            struct diffstat_t *diffstat)
4183{
4184        if (diff_unmodified_pair(p))
4185                return;
4186
4187        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4188            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4189                return; /* no useful stat for tree diffs */
4190
4191        run_diffstat(p, o, diffstat);
4192}
4193
4194static void diff_flush_checkdiff(struct diff_filepair *p,
4195                struct diff_options *o)
4196{
4197        if (diff_unmodified_pair(p))
4198                return;
4199
4200        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4201            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4202                return; /* nothing to check in tree diffs */
4203
4204        run_checkdiff(p, o);
4205}
4206
4207int diff_queue_is_empty(void)
4208{
4209        struct diff_queue_struct *q = &diff_queued_diff;
4210        int i;
4211        for (i = 0; i < q->nr; i++)
4212                if (!diff_unmodified_pair(q->queue[i]))
4213                        return 0;
4214        return 1;
4215}
4216
4217#if DIFF_DEBUG
4218void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4219{
4220        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4221                x, one ? one : "",
4222                s->path,
4223                DIFF_FILE_VALID(s) ? "valid" : "invalid",
4224                s->mode,
4225                s->sha1_valid ? sha1_to_hex(s->sha1) : "");
4226        fprintf(stderr, "queue[%d] %s size %lu\n",
4227                x, one ? one : "",
4228                s->size);
4229}
4230
4231void diff_debug_filepair(const struct diff_filepair *p, int i)
4232{
4233        diff_debug_filespec(p->one, i, "one");
4234        diff_debug_filespec(p->two, i, "two");
4235        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4236                p->score, p->status ? p->status : '?',
4237                p->one->rename_used, p->broken_pair);
4238}
4239
4240void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4241{
4242        int i;
4243        if (msg)
4244                fprintf(stderr, "%s\n", msg);
4245        fprintf(stderr, "q->nr = %d\n", q->nr);
4246        for (i = 0; i < q->nr; i++) {
4247                struct diff_filepair *p = q->queue[i];
4248                diff_debug_filepair(p, i);
4249        }
4250}
4251#endif
4252
4253static void diff_resolve_rename_copy(void)
4254{
4255        int i;
4256        struct diff_filepair *p;
4257        struct diff_queue_struct *q = &diff_queued_diff;
4258
4259        diff_debug_queue("resolve-rename-copy", q);
4260
4261        for (i = 0; i < q->nr; i++) {
4262                p = q->queue[i];
4263                p->status = 0; /* undecided */
4264                if (DIFF_PAIR_UNMERGED(p))
4265                        p->status = DIFF_STATUS_UNMERGED;
4266                else if (!DIFF_FILE_VALID(p->one))
4267                        p->status = DIFF_STATUS_ADDED;
4268                else if (!DIFF_FILE_VALID(p->two))
4269                        p->status = DIFF_STATUS_DELETED;
4270                else if (DIFF_PAIR_TYPE_CHANGED(p))
4271                        p->status = DIFF_STATUS_TYPE_CHANGED;
4272
4273                /* from this point on, we are dealing with a pair
4274                 * whose both sides are valid and of the same type, i.e.
4275                 * either in-place edit or rename/copy edit.
4276                 */
4277                else if (DIFF_PAIR_RENAME(p)) {
4278                        /*
4279                         * A rename might have re-connected a broken
4280                         * pair up, causing the pathnames to be the
4281                         * same again. If so, that's not a rename at
4282                         * all, just a modification..
4283                         *
4284                         * Otherwise, see if this source was used for
4285                         * multiple renames, in which case we decrement
4286                         * the count, and call it a copy.
4287                         */
4288                        if (!strcmp(p->one->path, p->two->path))
4289                                p->status = DIFF_STATUS_MODIFIED;
4290                        else if (--p->one->rename_used > 0)
4291                                p->status = DIFF_STATUS_COPIED;
4292                        else
4293                                p->status = DIFF_STATUS_RENAMED;
4294                }
4295                else if (hashcmp(p->one->sha1, p->two->sha1) ||
4296                         p->one->mode != p->two->mode ||
4297                         p->one->dirty_submodule ||
4298                         p->two->dirty_submodule ||
4299                         is_null_sha1(p->one->sha1))
4300                        p->status = DIFF_STATUS_MODIFIED;
4301                else {
4302                        /* This is a "no-change" entry and should not
4303                         * happen anymore, but prepare for broken callers.
4304                         */
4305                        error("feeding unmodified %s to diffcore",
4306                              p->one->path);
4307                        p->status = DIFF_STATUS_UNKNOWN;
4308                }
4309        }
4310        diff_debug_queue("resolve-rename-copy done", q);
4311}
4312
4313static int check_pair_status(struct diff_filepair *p)
4314{
4315        switch (p->status) {
4316        case DIFF_STATUS_UNKNOWN:
4317                return 0;
4318        case 0:
4319                die("internal error in diff-resolve-rename-copy");
4320        default:
4321                return 1;
4322        }
4323}
4324
4325static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4326{
4327        int fmt = opt->output_format;
4328
4329        if (fmt & DIFF_FORMAT_CHECKDIFF)
4330                diff_flush_checkdiff(p, opt);
4331        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4332                diff_flush_raw(p, opt);
4333        else if (fmt & DIFF_FORMAT_NAME) {
4334                const char *name_a, *name_b;
4335                name_a = p->two->path;
4336                name_b = NULL;
4337                strip_prefix(opt->prefix_length, &name_a, &name_b);
4338                write_name_quoted(name_a, opt->file, opt->line_termination);
4339        }
4340}
4341
4342static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4343{
4344        if (fs->mode)
4345                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4346        else
4347                fprintf(file, " %s ", newdelete);
4348        write_name_quoted(fs->path, file, '\n');
4349}
4350
4351
4352static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4353                const char *line_prefix)
4354{
4355        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4356                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4357                        p->two->mode, show_name ? ' ' : '\n');
4358                if (show_name) {
4359                        write_name_quoted(p->two->path, file, '\n');
4360                }
4361        }
4362}
4363
4364static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4365                        const char *line_prefix)
4366{
4367        char *names = pprint_rename(p->one->path, p->two->path);
4368
4369        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4370        free(names);
4371        show_mode_change(file, p, 0, line_prefix);
4372}
4373
4374static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4375{
4376        FILE *file = opt->file;
4377        const char *line_prefix = diff_line_prefix(opt);
4378
4379        switch(p->status) {
4380        case DIFF_STATUS_DELETED:
4381                fputs(line_prefix, file);
4382                show_file_mode_name(file, "delete", p->one);
4383                break;
4384        case DIFF_STATUS_ADDED:
4385                fputs(line_prefix, file);
4386                show_file_mode_name(file, "create", p->two);
4387                break;
4388        case DIFF_STATUS_COPIED:
4389                fputs(line_prefix, file);
4390                show_rename_copy(file, "copy", p, line_prefix);
4391                break;
4392        case DIFF_STATUS_RENAMED:
4393                fputs(line_prefix, file);
4394                show_rename_copy(file, "rename", p, line_prefix);
4395                break;
4396        default:
4397                if (p->score) {
4398                        fprintf(file, "%s rewrite ", line_prefix);
4399                        write_name_quoted(p->two->path, file, ' ');
4400                        fprintf(file, "(%d%%)\n", similarity_index(p));
4401                }
4402                show_mode_change(file, p, !p->score, line_prefix);
4403                break;
4404        }
4405}
4406
4407struct patch_id_t {
4408        git_SHA_CTX *ctx;
4409        int patchlen;
4410};
4411
4412static int remove_space(char *line, int len)
4413{
4414        int i;
4415        char *dst = line;
4416        unsigned char c;
4417
4418        for (i = 0; i < len; i++)
4419                if (!isspace((c = line[i])))
4420                        *dst++ = c;
4421
4422        return dst - line;
4423}
4424
4425static void patch_id_consume(void *priv, char *line, unsigned long len)
4426{
4427        struct patch_id_t *data = priv;
4428        int new_len;
4429
4430        /* Ignore line numbers when computing the SHA1 of the patch */
4431        if (starts_with(line, "@@ -"))
4432                return;
4433
4434        new_len = remove_space(line, len);
4435
4436        git_SHA1_Update(data->ctx, line, new_len);
4437        data->patchlen += new_len;
4438}
4439
4440/* returns 0 upon success, and writes result into sha1 */
4441static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
4442{
4443        struct diff_queue_struct *q = &diff_queued_diff;
4444        int i;
4445        git_SHA_CTX ctx;
4446        struct patch_id_t data;
4447        char buffer[PATH_MAX * 4 + 20];
4448
4449        git_SHA1_Init(&ctx);
4450        memset(&data, 0, sizeof(struct patch_id_t));
4451        data.ctx = &ctx;
4452
4453        for (i = 0; i < q->nr; i++) {
4454                xpparam_t xpp;
4455                xdemitconf_t xecfg;
4456                mmfile_t mf1, mf2;
4457                struct diff_filepair *p = q->queue[i];
4458                int len1, len2;
4459
4460                memset(&xpp, 0, sizeof(xpp));
4461                memset(&xecfg, 0, sizeof(xecfg));
4462                if (p->status == 0)
4463                        return error("internal diff status error");
4464                if (p->status == DIFF_STATUS_UNKNOWN)
4465                        continue;
4466                if (diff_unmodified_pair(p))
4467                        continue;
4468                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4469                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4470                        continue;
4471                if (DIFF_PAIR_UNMERGED(p))
4472                        continue;
4473
4474                diff_fill_sha1_info(p->one);
4475                diff_fill_sha1_info(p->two);
4476                if (fill_mmfile(&mf1, p->one) < 0 ||
4477                                fill_mmfile(&mf2, p->two) < 0)
4478                        return error("unable to read files to diff");
4479
4480                len1 = remove_space(p->one->path, strlen(p->one->path));
4481                len2 = remove_space(p->two->path, strlen(p->two->path));
4482                if (p->one->mode == 0)
4483                        len1 = snprintf(buffer, sizeof(buffer),
4484                                        "diff--gita/%.*sb/%.*s"
4485                                        "newfilemode%06o"
4486                                        "---/dev/null"
4487                                        "+++b/%.*s",
4488                                        len1, p->one->path,
4489                                        len2, p->two->path,
4490                                        p->two->mode,
4491                                        len2, p->two->path);
4492                else if (p->two->mode == 0)
4493                        len1 = snprintf(buffer, sizeof(buffer),
4494                                        "diff--gita/%.*sb/%.*s"
4495                                        "deletedfilemode%06o"
4496                                        "---a/%.*s"
4497                                        "+++/dev/null",
4498                                        len1, p->one->path,
4499                                        len2, p->two->path,
4500                                        p->one->mode,
4501                                        len1, p->one->path);
4502                else
4503                        len1 = snprintf(buffer, sizeof(buffer),
4504                                        "diff--gita/%.*sb/%.*s"
4505                                        "---a/%.*s"
4506                                        "+++b/%.*s",
4507                                        len1, p->one->path,
4508                                        len2, p->two->path,
4509                                        len1, p->one->path,
4510                                        len2, p->two->path);
4511                git_SHA1_Update(&ctx, buffer, len1);
4512
4513                if (diff_filespec_is_binary(p->one) ||
4514                    diff_filespec_is_binary(p->two)) {
4515                        git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4516                        git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4517                        continue;
4518                }
4519
4520                xpp.flags = 0;
4521                xecfg.ctxlen = 3;
4522                xecfg.flags = 0;
4523                if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4524                                  &xpp, &xecfg))
4525                        return error("unable to generate patch-id diff for %s",
4526                                     p->one->path);
4527        }
4528
4529        git_SHA1_Final(sha1, &ctx);
4530        return 0;
4531}
4532
4533int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4534{
4535        struct diff_queue_struct *q = &diff_queued_diff;
4536        int i;
4537        int result = diff_get_patch_id(options, sha1);
4538
4539        for (i = 0; i < q->nr; i++)
4540                diff_free_filepair(q->queue[i]);
4541
4542        free(q->queue);
4543        DIFF_QUEUE_CLEAR(q);
4544
4545        return result;
4546}
4547
4548static int is_summary_empty(const struct diff_queue_struct *q)
4549{
4550        int i;
4551
4552        for (i = 0; i < q->nr; i++) {
4553                const struct diff_filepair *p = q->queue[i];
4554
4555                switch (p->status) {
4556                case DIFF_STATUS_DELETED:
4557                case DIFF_STATUS_ADDED:
4558                case DIFF_STATUS_COPIED:
4559                case DIFF_STATUS_RENAMED:
4560                        return 0;
4561                default:
4562                        if (p->score)
4563                                return 0;
4564                        if (p->one->mode && p->two->mode &&
4565                            p->one->mode != p->two->mode)
4566                                return 0;
4567                        break;
4568                }
4569        }
4570        return 1;
4571}
4572
4573static const char rename_limit_warning[] =
4574"inexact rename detection was skipped due to too many files.";
4575
4576static const char degrade_cc_to_c_warning[] =
4577"only found copies from modified paths due to too many files.";
4578
4579static const char rename_limit_advice[] =
4580"you may want to set your %s variable to at least "
4581"%d and retry the command.";
4582
4583void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4584{
4585        if (degraded_cc)
4586                warning(degrade_cc_to_c_warning);
4587        else if (needed)
4588                warning(rename_limit_warning);
4589        else
4590                return;
4591        if (0 < needed && needed < 32767)
4592                warning(rename_limit_advice, varname, needed);
4593}
4594
4595void diff_flush(struct diff_options *options)
4596{
4597        struct diff_queue_struct *q = &diff_queued_diff;
4598        int i, output_format = options->output_format;
4599        int separator = 0;
4600        int dirstat_by_line = 0;
4601
4602        /*
4603         * Order: raw, stat, summary, patch
4604         * or:    name/name-status/checkdiff (other bits clear)
4605         */
4606        if (!q->nr)
4607                goto free_queue;
4608
4609        if (output_format & (DIFF_FORMAT_RAW |
4610                             DIFF_FORMAT_NAME |
4611                             DIFF_FORMAT_NAME_STATUS |
4612                             DIFF_FORMAT_CHECKDIFF)) {
4613                for (i = 0; i < q->nr; i++) {
4614                        struct diff_filepair *p = q->queue[i];
4615                        if (check_pair_status(p))
4616                                flush_one_pair(p, options);
4617                }
4618                separator++;
4619        }
4620
4621        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4622                dirstat_by_line = 1;
4623
4624        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4625            dirstat_by_line) {
4626                struct diffstat_t diffstat;
4627
4628                memset(&diffstat, 0, sizeof(struct diffstat_t));
4629                for (i = 0; i < q->nr; i++) {
4630                        struct diff_filepair *p = q->queue[i];
4631                        if (check_pair_status(p))
4632                                diff_flush_stat(p, options, &diffstat);
4633                }
4634                if (output_format & DIFF_FORMAT_NUMSTAT)
4635                        show_numstat(&diffstat, options);
4636                if (output_format & DIFF_FORMAT_DIFFSTAT)
4637                        show_stats(&diffstat, options);
4638                if (output_format & DIFF_FORMAT_SHORTSTAT)
4639                        show_shortstats(&diffstat, options);
4640                if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
4641                        show_dirstat_by_line(&diffstat, options);
4642                free_diffstat_info(&diffstat);
4643                separator++;
4644        }
4645        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4646                show_dirstat(options);
4647
4648        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4649                for (i = 0; i < q->nr; i++) {
4650                        diff_summary(options, q->queue[i]);
4651                }
4652                separator++;
4653        }
4654
4655        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4656            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4657            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4658                /*
4659                 * run diff_flush_patch for the exit status. setting
4660                 * options->file to /dev/null should be safe, because we
4661                 * aren't supposed to produce any output anyway.
4662                 */
4663                if (options->close_file)
4664                        fclose(options->file);
4665                options->file = fopen("/dev/null", "w");
4666                if (!options->file)
4667                        die_errno("Could not open /dev/null");
4668                options->close_file = 1;
4669                for (i = 0; i < q->nr; i++) {
4670                        struct diff_filepair *p = q->queue[i];
4671                        if (check_pair_status(p))
4672                                diff_flush_patch(p, options);
4673                        if (options->found_changes)
4674                                break;
4675                }
4676        }
4677
4678        if (output_format & DIFF_FORMAT_PATCH) {
4679                if (separator) {
4680                        fprintf(options->file, "%s%c",
4681                                diff_line_prefix(options),
4682                                options->line_termination);
4683                        if (options->stat_sep) {
4684                                /* attach patch instead of inline */
4685                                fputs(options->stat_sep, options->file);
4686                        }
4687                }
4688
4689                for (i = 0; i < q->nr; i++) {
4690                        struct diff_filepair *p = q->queue[i];
4691                        if (check_pair_status(p))
4692                                diff_flush_patch(p, options);
4693                }
4694        }
4695
4696        if (output_format & DIFF_FORMAT_CALLBACK)
4697                options->format_callback(q, options, options->format_callback_data);
4698
4699        for (i = 0; i < q->nr; i++)
4700                diff_free_filepair(q->queue[i]);
4701free_queue:
4702        free(q->queue);
4703        DIFF_QUEUE_CLEAR(q);
4704        if (options->close_file)
4705                fclose(options->file);
4706
4707        /*
4708         * Report the content-level differences with HAS_CHANGES;
4709         * diff_addremove/diff_change does not set the bit when
4710         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4711         */
4712        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4713                if (options->found_changes)
4714                        DIFF_OPT_SET(options, HAS_CHANGES);
4715                else
4716                        DIFF_OPT_CLR(options, HAS_CHANGES);
4717        }
4718}
4719
4720static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
4721{
4722        return (((p->status == DIFF_STATUS_MODIFIED) &&
4723                 ((p->score &&
4724                   filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
4725                  (!p->score &&
4726                   filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
4727                ((p->status != DIFF_STATUS_MODIFIED) &&
4728                 filter_bit_tst(p->status, options)));
4729}
4730
4731static void diffcore_apply_filter(struct diff_options *options)
4732{
4733        int i;
4734        struct diff_queue_struct *q = &diff_queued_diff;
4735        struct diff_queue_struct outq;
4736
4737        DIFF_QUEUE_CLEAR(&outq);
4738
4739        if (!options->filter)
4740                return;
4741
4742        if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
4743                int found;
4744                for (i = found = 0; !found && i < q->nr; i++) {
4745                        if (match_filter(options, q->queue[i]))
4746                                found++;
4747                }
4748                if (found)
4749                        return;
4750
4751                /* otherwise we will clear the whole queue
4752                 * by copying the empty outq at the end of this
4753                 * function, but first clear the current entries
4754                 * in the queue.
4755                 */
4756                for (i = 0; i < q->nr; i++)
4757                        diff_free_filepair(q->queue[i]);
4758        }
4759        else {
4760                /* Only the matching ones */
4761                for (i = 0; i < q->nr; i++) {
4762                        struct diff_filepair *p = q->queue[i];
4763                        if (match_filter(options, p))
4764                                diff_q(&outq, p);
4765                        else
4766                                diff_free_filepair(p);
4767                }
4768        }
4769        free(q->queue);
4770        *q = outq;
4771}
4772
4773/* Check whether two filespecs with the same mode and size are identical */
4774static int diff_filespec_is_identical(struct diff_filespec *one,
4775                                      struct diff_filespec *two)
4776{
4777        if (S_ISGITLINK(one->mode))
4778                return 0;
4779        if (diff_populate_filespec(one, 0))
4780                return 0;
4781        if (diff_populate_filespec(two, 0))
4782                return 0;
4783        return !memcmp(one->data, two->data, one->size);
4784}
4785
4786static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
4787{
4788        if (p->done_skip_stat_unmatch)
4789                return p->skip_stat_unmatch_result;
4790
4791        p->done_skip_stat_unmatch = 1;
4792        p->skip_stat_unmatch_result = 0;
4793        /*
4794         * 1. Entries that come from stat info dirtiness
4795         *    always have both sides (iow, not create/delete),
4796         *    one side of the object name is unknown, with
4797         *    the same mode and size.  Keep the ones that
4798         *    do not match these criteria.  They have real
4799         *    differences.
4800         *
4801         * 2. At this point, the file is known to be modified,
4802         *    with the same mode and size, and the object
4803         *    name of one side is unknown.  Need to inspect
4804         *    the identical contents.
4805         */
4806        if (!DIFF_FILE_VALID(p->one) || /* (1) */
4807            !DIFF_FILE_VALID(p->two) ||
4808            (p->one->sha1_valid && p->two->sha1_valid) ||
4809            (p->one->mode != p->two->mode) ||
4810            diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
4811            diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
4812            (p->one->size != p->two->size) ||
4813            !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4814                p->skip_stat_unmatch_result = 1;
4815        return p->skip_stat_unmatch_result;
4816}
4817
4818static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4819{
4820        int i;
4821        struct diff_queue_struct *q = &diff_queued_diff;
4822        struct diff_queue_struct outq;
4823        DIFF_QUEUE_CLEAR(&outq);
4824
4825        for (i = 0; i < q->nr; i++) {
4826                struct diff_filepair *p = q->queue[i];
4827
4828                if (diff_filespec_check_stat_unmatch(p))
4829                        diff_q(&outq, p);
4830                else {
4831                        /*
4832                         * The caller can subtract 1 from skip_stat_unmatch
4833                         * to determine how many paths were dirty only
4834                         * due to stat info mismatch.
4835                         */
4836                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4837                                diffopt->skip_stat_unmatch++;
4838                        diff_free_filepair(p);
4839                }
4840        }
4841        free(q->queue);
4842        *q = outq;
4843}
4844
4845static int diffnamecmp(const void *a_, const void *b_)
4846{
4847        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4848        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4849        const char *name_a, *name_b;
4850
4851        name_a = a->one ? a->one->path : a->two->path;
4852        name_b = b->one ? b->one->path : b->two->path;
4853        return strcmp(name_a, name_b);
4854}
4855
4856void diffcore_fix_diff_index(struct diff_options *options)
4857{
4858        struct diff_queue_struct *q = &diff_queued_diff;
4859        qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4860}
4861
4862void diffcore_std(struct diff_options *options)
4863{
4864        /* NOTE please keep the following in sync with diff_tree_combined() */
4865        if (options->skip_stat_unmatch)
4866                diffcore_skip_stat_unmatch(options);
4867        if (!options->found_follow) {
4868                /* See try_to_follow_renames() in tree-diff.c */
4869                if (options->break_opt != -1)
4870                        diffcore_break(options->break_opt);
4871                if (options->detect_rename)
4872                        diffcore_rename(options);
4873                if (options->break_opt != -1)
4874                        diffcore_merge_broken();
4875        }
4876        if (options->pickaxe)
4877                diffcore_pickaxe(options);
4878        if (options->orderfile)
4879                diffcore_order(options->orderfile);
4880        if (!options->found_follow)
4881                /* See try_to_follow_renames() in tree-diff.c */
4882                diff_resolve_rename_copy();
4883        diffcore_apply_filter(options);
4884
4885        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4886                DIFF_OPT_SET(options, HAS_CHANGES);
4887        else
4888                DIFF_OPT_CLR(options, HAS_CHANGES);
4889
4890        options->found_follow = 0;
4891}
4892
4893int diff_result_code(struct diff_options *opt, int status)
4894{
4895        int result = 0;
4896
4897        diff_warn_rename_limit("diff.renameLimit",
4898                               opt->needed_rename_limit,
4899                               opt->degraded_cc_to_c);
4900        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4901            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4902                return status;
4903        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4904            DIFF_OPT_TST(opt, HAS_CHANGES))
4905                result |= 01;
4906        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4907            DIFF_OPT_TST(opt, CHECK_FAILED))
4908                result |= 02;
4909        return result;
4910}
4911
4912int diff_can_quit_early(struct diff_options *opt)
4913{
4914        return (DIFF_OPT_TST(opt, QUICK) &&
4915                !opt->filter &&
4916                DIFF_OPT_TST(opt, HAS_CHANGES));
4917}
4918
4919/*
4920 * Shall changes to this submodule be ignored?
4921 *
4922 * Submodule changes can be configured to be ignored separately for each path,
4923 * but that configuration can be overridden from the command line.
4924 */
4925static int is_submodule_ignored(const char *path, struct diff_options *options)
4926{
4927        int ignored = 0;
4928        unsigned orig_flags = options->flags;
4929        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4930                set_diffopt_flags_from_submodule_config(options, path);
4931        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4932                ignored = 1;
4933        options->flags = orig_flags;
4934        return ignored;
4935}
4936
4937void diff_addremove(struct diff_options *options,
4938                    int addremove, unsigned mode,
4939                    const unsigned char *sha1,
4940                    int sha1_valid,
4941                    const char *concatpath, unsigned dirty_submodule)
4942{
4943        struct diff_filespec *one, *two;
4944
4945        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4946                return;
4947
4948        /* This may look odd, but it is a preparation for
4949         * feeding "there are unchanged files which should
4950         * not produce diffs, but when you are doing copy
4951         * detection you would need them, so here they are"
4952         * entries to the diff-core.  They will be prefixed
4953         * with something like '=' or '*' (I haven't decided
4954         * which but should not make any difference).
4955         * Feeding the same new and old to diff_change()
4956         * also has the same effect.
4957         * Before the final output happens, they are pruned after
4958         * merged into rename/copy pairs as appropriate.
4959         */
4960        if (DIFF_OPT_TST(options, REVERSE_DIFF))
4961                addremove = (addremove == '+' ? '-' :
4962                             addremove == '-' ? '+' : addremove);
4963
4964        if (options->prefix &&
4965            strncmp(concatpath, options->prefix, options->prefix_length))
4966                return;
4967
4968        one = alloc_filespec(concatpath);
4969        two = alloc_filespec(concatpath);
4970
4971        if (addremove != '+')
4972                fill_filespec(one, sha1, sha1_valid, mode);
4973        if (addremove != '-') {
4974                fill_filespec(two, sha1, sha1_valid, mode);
4975                two->dirty_submodule = dirty_submodule;
4976        }
4977
4978        diff_queue(&diff_queued_diff, one, two);
4979        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4980                DIFF_OPT_SET(options, HAS_CHANGES);
4981}
4982
4983void diff_change(struct diff_options *options,
4984                 unsigned old_mode, unsigned new_mode,
4985                 const unsigned char *old_sha1,
4986                 const unsigned char *new_sha1,
4987                 int old_sha1_valid, int new_sha1_valid,
4988                 const char *concatpath,
4989                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4990{
4991        struct diff_filespec *one, *two;
4992        struct diff_filepair *p;
4993
4994        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4995            is_submodule_ignored(concatpath, options))
4996                return;
4997
4998        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4999                unsigned tmp;
5000                const unsigned char *tmp_c;
5001                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
5002                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
5003                tmp = old_sha1_valid; old_sha1_valid = new_sha1_valid;
5004                        new_sha1_valid = tmp;
5005                tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
5006                        new_dirty_submodule = tmp;
5007        }
5008
5009        if (options->prefix &&
5010            strncmp(concatpath, options->prefix, options->prefix_length))
5011                return;
5012
5013        one = alloc_filespec(concatpath);
5014        two = alloc_filespec(concatpath);
5015        fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
5016        fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
5017        one->dirty_submodule = old_dirty_submodule;
5018        two->dirty_submodule = new_dirty_submodule;
5019        p = diff_queue(&diff_queued_diff, one, two);
5020
5021        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5022                return;
5023
5024        if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
5025            !diff_filespec_check_stat_unmatch(p))
5026                return;
5027
5028        DIFF_OPT_SET(options, HAS_CHANGES);
5029}
5030
5031struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
5032{
5033        struct diff_filepair *pair;
5034        struct diff_filespec *one, *two;
5035
5036        if (options->prefix &&
5037            strncmp(path, options->prefix, options->prefix_length))
5038                return NULL;
5039
5040        one = alloc_filespec(path);
5041        two = alloc_filespec(path);
5042        pair = diff_queue(&diff_queued_diff, one, two);
5043        pair->is_unmerged = 1;
5044        return pair;
5045}
5046
5047static char *run_textconv(const char *pgm, struct diff_filespec *spec,
5048                size_t *outsize)
5049{
5050        struct diff_tempfile *temp;
5051        const char *argv[3];
5052        const char **arg = argv;
5053        struct child_process child = CHILD_PROCESS_INIT;
5054        struct strbuf buf = STRBUF_INIT;
5055        int err = 0;
5056
5057        temp = prepare_temp_file(spec->path, spec);
5058        *arg++ = pgm;
5059        *arg++ = temp->name;
5060        *arg = NULL;
5061
5062        child.use_shell = 1;
5063        child.argv = argv;
5064        child.out = -1;
5065        if (start_command(&child)) {
5066                remove_tempfile();
5067                return NULL;
5068        }
5069
5070        if (strbuf_read(&buf, child.out, 0) < 0)
5071                err = error("error reading from textconv command '%s'", pgm);
5072        close(child.out);
5073
5074        if (finish_command(&child) || err) {
5075                strbuf_release(&buf);
5076                remove_tempfile();
5077                return NULL;
5078        }
5079        remove_tempfile();
5080
5081        return strbuf_detach(&buf, outsize);
5082}
5083
5084size_t fill_textconv(struct userdiff_driver *driver,
5085                     struct diff_filespec *df,
5086                     char **outbuf)
5087{
5088        size_t size;
5089
5090        if (!driver) {
5091                if (!DIFF_FILE_VALID(df)) {
5092                        *outbuf = "";
5093                        return 0;
5094                }
5095                if (diff_populate_filespec(df, 0))
5096                        die("unable to read files to diff");
5097                *outbuf = df->data;
5098                return df->size;
5099        }
5100
5101        if (!driver->textconv)
5102                die("BUG: fill_textconv called with non-textconv driver");
5103
5104        if (driver->textconv_cache && df->sha1_valid) {
5105                *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
5106                                          &size);
5107                if (*outbuf)
5108                        return size;
5109        }
5110
5111        *outbuf = run_textconv(driver->textconv, df, &size);
5112        if (!*outbuf)
5113                die("unable to read files to diff");
5114
5115        if (driver->textconv_cache && df->sha1_valid) {
5116                /* ignore errors, as we might be in a readonly repository */
5117                notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
5118                                size);
5119                /*
5120                 * we could save up changes and flush them all at the end,
5121                 * but we would need an extra call after all diffing is done.
5122                 * Since generating a cache entry is the slow path anyway,
5123                 * this extra overhead probably isn't a big deal.
5124                 */
5125                notes_cache_write(driver->textconv_cache);
5126        }
5127
5128        return size;
5129}
5130
5131void setup_diff_pager(struct diff_options *opt)
5132{
5133        /*
5134         * If the user asked for our exit code, then either they want --quiet
5135         * or --exit-code. We should definitely not bother with a pager in the
5136         * former case, as we will generate no output. Since we still properly
5137         * report our exit code even when a pager is run, we _could_ run a
5138         * pager with --exit-code. But since we have not done so historically,
5139         * and because it is easy to find people oneline advising "git diff
5140         * --exit-code" in hooks and other scripts, we do not do so.
5141         */
5142        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5143            check_pager_config("diff") != 0)
5144                setup_pager();
5145}