528d25ca9c3ec8df316bf2cd331151d7a71d5dd3
   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 "sigchain.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,       /* PLAIN */
  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, "plain"))
  59                return DIFF_PLAIN;
  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 */
 171int git_diff_ui_config(const char *var, const char *value, void *cb)
 172{
 173        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 174                diff_use_color_default = git_config_colorbool(var, value);
 175                return 0;
 176        }
 177        if (!strcmp(var, "diff.context")) {
 178                diff_context_default = git_config_int(var, value);
 179                if (diff_context_default < 0)
 180                        return -1;
 181                return 0;
 182        }
 183        if (!strcmp(var, "diff.renames")) {
 184                diff_detect_rename_default = git_config_rename(var, value);
 185                return 0;
 186        }
 187        if (!strcmp(var, "diff.autorefreshindex")) {
 188                diff_auto_refresh_index = git_config_bool(var, value);
 189                return 0;
 190        }
 191        if (!strcmp(var, "diff.mnemonicprefix")) {
 192                diff_mnemonic_prefix = git_config_bool(var, value);
 193                return 0;
 194        }
 195        if (!strcmp(var, "diff.noprefix")) {
 196                diff_no_prefix = git_config_bool(var, value);
 197                return 0;
 198        }
 199        if (!strcmp(var, "diff.statgraphwidth")) {
 200                diff_stat_graph_width = git_config_int(var, value);
 201                return 0;
 202        }
 203        if (!strcmp(var, "diff.external"))
 204                return git_config_string(&external_diff_cmd_cfg, var, value);
 205        if (!strcmp(var, "diff.wordregex"))
 206                return git_config_string(&diff_word_regex_cfg, var, value);
 207        if (!strcmp(var, "diff.orderfile"))
 208                return git_config_pathname(&diff_order_file_cfg, var, value);
 209
 210        if (!strcmp(var, "diff.ignoresubmodules"))
 211                handle_ignore_submodules_arg(&default_diff_options, value);
 212
 213        if (!strcmp(var, "diff.submodule")) {
 214                if (parse_submodule_params(&default_diff_options, value))
 215                        warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 216                                value);
 217                return 0;
 218        }
 219
 220        if (!strcmp(var, "diff.algorithm")) {
 221                diff_algorithm = parse_algorithm_value(value);
 222                if (diff_algorithm < 0)
 223                        return -1;
 224                return 0;
 225        }
 226
 227        if (git_color_config(var, value, cb) < 0)
 228                return -1;
 229
 230        return git_diff_basic_config(var, value, cb);
 231}
 232
 233int git_diff_basic_config(const char *var, const char *value, void *cb)
 234{
 235        const char *name;
 236
 237        if (!strcmp(var, "diff.renamelimit")) {
 238                diff_rename_limit_default = git_config_int(var, value);
 239                return 0;
 240        }
 241
 242        if (userdiff_config(var, value) < 0)
 243                return -1;
 244
 245        if (skip_prefix(var, "diff.color.", &name) ||
 246            skip_prefix(var, "color.diff.", &name)) {
 247                int slot = parse_diff_color_slot(name);
 248                if (slot < 0)
 249                        return 0;
 250                if (!value)
 251                        return config_error_nonbool(var);
 252                return color_parse(value, diff_colors[slot]);
 253        }
 254
 255        /* like GNU diff's --suppress-blank-empty option  */
 256        if (!strcmp(var, "diff.suppressblankempty") ||
 257                        /* for backwards compatibility */
 258                        !strcmp(var, "diff.suppress-blank-empty")) {
 259                diff_suppress_blank_empty = git_config_bool(var, value);
 260                return 0;
 261        }
 262
 263        if (!strcmp(var, "diff.dirstat")) {
 264                struct strbuf errmsg = STRBUF_INIT;
 265                default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 266                if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 267                        warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 268                                errmsg.buf);
 269                strbuf_release(&errmsg);
 270                diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 271                return 0;
 272        }
 273
 274        if (starts_with(var, "submodule."))
 275                return parse_submodule_config_option(var, value);
 276
 277        return git_default_config(var, value, cb);
 278}
 279
 280static char *quote_two(const char *one, const char *two)
 281{
 282        int need_one = quote_c_style(one, NULL, NULL, 1);
 283        int need_two = quote_c_style(two, NULL, NULL, 1);
 284        struct strbuf res = STRBUF_INIT;
 285
 286        if (need_one + need_two) {
 287                strbuf_addch(&res, '"');
 288                quote_c_style(one, &res, NULL, 1);
 289                quote_c_style(two, &res, NULL, 1);
 290                strbuf_addch(&res, '"');
 291        } else {
 292                strbuf_addstr(&res, one);
 293                strbuf_addstr(&res, two);
 294        }
 295        return strbuf_detach(&res, NULL);
 296}
 297
 298static const char *external_diff(void)
 299{
 300        static const char *external_diff_cmd = NULL;
 301        static int done_preparing = 0;
 302
 303        if (done_preparing)
 304                return external_diff_cmd;
 305        external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 306        if (!external_diff_cmd)
 307                external_diff_cmd = external_diff_cmd_cfg;
 308        done_preparing = 1;
 309        return external_diff_cmd;
 310}
 311
 312/*
 313 * Keep track of files used for diffing. Sometimes such an entry
 314 * refers to a temporary file, sometimes to an existing file, and
 315 * sometimes to "/dev/null".
 316 */
 317static struct diff_tempfile {
 318        /*
 319         * filename external diff should read from, or NULL if this
 320         * entry is currently not in use:
 321         */
 322        const char *name;
 323
 324        char hex[41];
 325        char mode[10];
 326
 327        /*
 328         * If this diff_tempfile instance refers to a temporary file,
 329         * this tempfile object is used to manage its lifetime.
 330         */
 331        struct tempfile tempfile;
 332} diff_temp[2];
 333
 334typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 335
 336struct emit_callback {
 337        int color_diff;
 338        unsigned ws_rule;
 339        int blank_at_eof_in_preimage;
 340        int blank_at_eof_in_postimage;
 341        int lno_in_preimage;
 342        int lno_in_postimage;
 343        sane_truncate_fn truncate;
 344        const char **label_path;
 345        struct diff_words_data *diff_words;
 346        struct diff_options *opt;
 347        int *found_changesp;
 348        struct strbuf *header;
 349};
 350
 351static int count_lines(const char *data, int size)
 352{
 353        int count, ch, completely_empty = 1, nl_just_seen = 0;
 354        count = 0;
 355        while (0 < size--) {
 356                ch = *data++;
 357                if (ch == '\n') {
 358                        count++;
 359                        nl_just_seen = 1;
 360                        completely_empty = 0;
 361                }
 362                else {
 363                        nl_just_seen = 0;
 364                        completely_empty = 0;
 365                }
 366        }
 367        if (completely_empty)
 368                return 0;
 369        if (!nl_just_seen)
 370                count++; /* no trailing newline */
 371        return count;
 372}
 373
 374static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 375{
 376        if (!DIFF_FILE_VALID(one)) {
 377                mf->ptr = (char *)""; /* does not matter */
 378                mf->size = 0;
 379                return 0;
 380        }
 381        else if (diff_populate_filespec(one, 0))
 382                return -1;
 383
 384        mf->ptr = one->data;
 385        mf->size = one->size;
 386        return 0;
 387}
 388
 389/* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 390static unsigned long diff_filespec_size(struct diff_filespec *one)
 391{
 392        if (!DIFF_FILE_VALID(one))
 393                return 0;
 394        diff_populate_filespec(one, CHECK_SIZE_ONLY);
 395        return one->size;
 396}
 397
 398static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 399{
 400        char *ptr = mf->ptr;
 401        long size = mf->size;
 402        int cnt = 0;
 403
 404        if (!size)
 405                return cnt;
 406        ptr += size - 1; /* pointing at the very end */
 407        if (*ptr != '\n')
 408                ; /* incomplete line */
 409        else
 410                ptr--; /* skip the last LF */
 411        while (mf->ptr < ptr) {
 412                char *prev_eol;
 413                for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 414                        if (*prev_eol == '\n')
 415                                break;
 416                if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 417                        break;
 418                cnt++;
 419                ptr = prev_eol - 1;
 420        }
 421        return cnt;
 422}
 423
 424static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 425                               struct emit_callback *ecbdata)
 426{
 427        int l1, l2, at;
 428        unsigned ws_rule = ecbdata->ws_rule;
 429        l1 = count_trailing_blank(mf1, ws_rule);
 430        l2 = count_trailing_blank(mf2, ws_rule);
 431        if (l2 <= l1) {
 432                ecbdata->blank_at_eof_in_preimage = 0;
 433                ecbdata->blank_at_eof_in_postimage = 0;
 434                return;
 435        }
 436        at = count_lines(mf1->ptr, mf1->size);
 437        ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 438
 439        at = count_lines(mf2->ptr, mf2->size);
 440        ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 441}
 442
 443static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 444                        int first, const char *line, int len)
 445{
 446        int has_trailing_newline, has_trailing_carriage_return;
 447        int nofirst;
 448        FILE *file = o->file;
 449
 450        fputs(diff_line_prefix(o), file);
 451
 452        if (len == 0) {
 453                has_trailing_newline = (first == '\n');
 454                has_trailing_carriage_return = (!has_trailing_newline &&
 455                                                (first == '\r'));
 456                nofirst = has_trailing_newline || has_trailing_carriage_return;
 457        } else {
 458                has_trailing_newline = (len > 0 && line[len-1] == '\n');
 459                if (has_trailing_newline)
 460                        len--;
 461                has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 462                if (has_trailing_carriage_return)
 463                        len--;
 464                nofirst = 0;
 465        }
 466
 467        if (len || !nofirst) {
 468                fputs(set, file);
 469                if (!nofirst)
 470                        fputc(first, file);
 471                fwrite(line, len, 1, file);
 472                fputs(reset, file);
 473        }
 474        if (has_trailing_carriage_return)
 475                fputc('\r', file);
 476        if (has_trailing_newline)
 477                fputc('\n', file);
 478}
 479
 480static void emit_line(struct diff_options *o, const char *set, const char *reset,
 481                      const char *line, int len)
 482{
 483        emit_line_0(o, set, reset, line[0], line+1, len-1);
 484}
 485
 486static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 487{
 488        if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 489              ecbdata->blank_at_eof_in_preimage &&
 490              ecbdata->blank_at_eof_in_postimage &&
 491              ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 492              ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 493                return 0;
 494        return ws_blank_line(line, len, ecbdata->ws_rule);
 495}
 496
 497static void emit_add_line(const char *reset,
 498                          struct emit_callback *ecbdata,
 499                          const char *line, int len)
 500{
 501        const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 502        const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 503
 504        if (!*ws)
 505                emit_line_0(ecbdata->opt, set, reset, '+', line, len);
 506        else if (new_blank_line_at_eof(ecbdata, line, len))
 507                /* Blank line at EOF - paint '+' as well */
 508                emit_line_0(ecbdata->opt, ws, reset, '+', line, len);
 509        else {
 510                /* Emit just the prefix, then the rest. */
 511                emit_line_0(ecbdata->opt, set, reset, '+', "", 0);
 512                ws_check_emit(line, len, ecbdata->ws_rule,
 513                              ecbdata->opt->file, set, reset, ws);
 514        }
 515}
 516
 517static void emit_hunk_header(struct emit_callback *ecbdata,
 518                             const char *line, int len)
 519{
 520        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
 521        const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 522        const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 523        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 524        static const char atat[2] = { '@', '@' };
 525        const char *cp, *ep;
 526        struct strbuf msgbuf = STRBUF_INIT;
 527        int org_len = len;
 528        int i = 1;
 529
 530        /*
 531         * As a hunk header must begin with "@@ -<old>, +<new> @@",
 532         * it always is at least 10 bytes long.
 533         */
 534        if (len < 10 ||
 535            memcmp(line, atat, 2) ||
 536            !(ep = memmem(line + 2, len - 2, atat, 2))) {
 537                emit_line(ecbdata->opt, plain, reset, line, len);
 538                return;
 539        }
 540        ep += 2; /* skip over @@ */
 541
 542        /* The hunk header in fraginfo color */
 543        strbuf_addstr(&msgbuf, frag);
 544        strbuf_add(&msgbuf, line, ep - line);
 545        strbuf_addstr(&msgbuf, reset);
 546
 547        /*
 548         * trailing "\r\n"
 549         */
 550        for ( ; i < 3; i++)
 551                if (line[len - i] == '\r' || line[len - i] == '\n')
 552                        len--;
 553
 554        /* blank before the func header */
 555        for (cp = ep; ep - line < len; ep++)
 556                if (*ep != ' ' && *ep != '\t')
 557                        break;
 558        if (ep != cp) {
 559                strbuf_addstr(&msgbuf, plain);
 560                strbuf_add(&msgbuf, cp, ep - cp);
 561                strbuf_addstr(&msgbuf, reset);
 562        }
 563
 564        if (ep < line + len) {
 565                strbuf_addstr(&msgbuf, func);
 566                strbuf_add(&msgbuf, ep, line + len - ep);
 567                strbuf_addstr(&msgbuf, reset);
 568        }
 569
 570        strbuf_add(&msgbuf, line + len, org_len - len);
 571        emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 572        strbuf_release(&msgbuf);
 573}
 574
 575static struct diff_tempfile *claim_diff_tempfile(void) {
 576        int i;
 577        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 578                if (!diff_temp[i].name)
 579                        return diff_temp + i;
 580        die("BUG: diff is failing to clean up its tempfiles");
 581}
 582
 583static void remove_tempfile(void)
 584{
 585        int i;
 586        for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 587                if (is_tempfile_active(&diff_temp[i].tempfile))
 588                        delete_tempfile(&diff_temp[i].tempfile);
 589                diff_temp[i].name = NULL;
 590        }
 591}
 592
 593static void print_line_count(FILE *file, int count)
 594{
 595        switch (count) {
 596        case 0:
 597                fprintf(file, "0,0");
 598                break;
 599        case 1:
 600                fprintf(file, "1");
 601                break;
 602        default:
 603                fprintf(file, "1,%d", count);
 604                break;
 605        }
 606}
 607
 608static void emit_rewrite_lines(struct emit_callback *ecb,
 609                               int prefix, const char *data, int size)
 610{
 611        const char *endp = NULL;
 612        static const char *nneof = " No newline at end of file\n";
 613        const char *old = diff_get_color(ecb->color_diff, DIFF_FILE_OLD);
 614        const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 615
 616        while (0 < size) {
 617                int len;
 618
 619                endp = memchr(data, '\n', size);
 620                len = endp ? (endp - data + 1) : size;
 621                if (prefix != '+') {
 622                        ecb->lno_in_preimage++;
 623                        emit_line_0(ecb->opt, old, reset, '-',
 624                                    data, len);
 625                } else {
 626                        ecb->lno_in_postimage++;
 627                        emit_add_line(reset, ecb, data, len);
 628                }
 629                size -= len;
 630                data += len;
 631        }
 632        if (!endp) {
 633                const char *plain = diff_get_color(ecb->color_diff,
 634                                                   DIFF_PLAIN);
 635                putc('\n', ecb->opt->file);
 636                emit_line_0(ecb->opt, plain, reset, '\\',
 637                            nneof, strlen(nneof));
 638        }
 639}
 640
 641static void emit_rewrite_diff(const char *name_a,
 642                              const char *name_b,
 643                              struct diff_filespec *one,
 644                              struct diff_filespec *two,
 645                              struct userdiff_driver *textconv_one,
 646                              struct userdiff_driver *textconv_two,
 647                              struct diff_options *o)
 648{
 649        int lc_a, lc_b;
 650        const char *name_a_tab, *name_b_tab;
 651        const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 652        const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 653        const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 654        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 655        const char *a_prefix, *b_prefix;
 656        char *data_one, *data_two;
 657        size_t size_one, size_two;
 658        struct emit_callback ecbdata;
 659        const char *line_prefix = diff_line_prefix(o);
 660
 661        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 662                a_prefix = o->b_prefix;
 663                b_prefix = o->a_prefix;
 664        } else {
 665                a_prefix = o->a_prefix;
 666                b_prefix = o->b_prefix;
 667        }
 668
 669        name_a += (*name_a == '/');
 670        name_b += (*name_b == '/');
 671        name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 672        name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 673
 674        strbuf_reset(&a_name);
 675        strbuf_reset(&b_name);
 676        quote_two_c_style(&a_name, a_prefix, name_a, 0);
 677        quote_two_c_style(&b_name, b_prefix, name_b, 0);
 678
 679        size_one = fill_textconv(textconv_one, one, &data_one);
 680        size_two = fill_textconv(textconv_two, two, &data_two);
 681
 682        memset(&ecbdata, 0, sizeof(ecbdata));
 683        ecbdata.color_diff = want_color(o->use_color);
 684        ecbdata.found_changesp = &o->found_changes;
 685        ecbdata.ws_rule = whitespace_rule(name_b);
 686        ecbdata.opt = o;
 687        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 688                mmfile_t mf1, mf2;
 689                mf1.ptr = (char *)data_one;
 690                mf2.ptr = (char *)data_two;
 691                mf1.size = size_one;
 692                mf2.size = size_two;
 693                check_blank_at_eof(&mf1, &mf2, &ecbdata);
 694        }
 695        ecbdata.lno_in_preimage = 1;
 696        ecbdata.lno_in_postimage = 1;
 697
 698        lc_a = count_lines(data_one, size_one);
 699        lc_b = count_lines(data_two, size_two);
 700        fprintf(o->file,
 701                "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 702                line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 703                line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 704                line_prefix, fraginfo);
 705        if (!o->irreversible_delete)
 706                print_line_count(o->file, lc_a);
 707        else
 708                fprintf(o->file, "?,?");
 709        fprintf(o->file, " +");
 710        print_line_count(o->file, lc_b);
 711        fprintf(o->file, " @@%s\n", reset);
 712        if (lc_a && !o->irreversible_delete)
 713                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 714        if (lc_b)
 715                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 716        if (textconv_one)
 717                free((char *)data_one);
 718        if (textconv_two)
 719                free((char *)data_two);
 720}
 721
 722struct diff_words_buffer {
 723        mmfile_t text;
 724        long alloc;
 725        struct diff_words_orig {
 726                const char *begin, *end;
 727        } *orig;
 728        int orig_nr, orig_alloc;
 729};
 730
 731static void diff_words_append(char *line, unsigned long len,
 732                struct diff_words_buffer *buffer)
 733{
 734        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 735        line++;
 736        len--;
 737        memcpy(buffer->text.ptr + buffer->text.size, line, len);
 738        buffer->text.size += len;
 739        buffer->text.ptr[buffer->text.size] = '\0';
 740}
 741
 742struct diff_words_style_elem {
 743        const char *prefix;
 744        const char *suffix;
 745        const char *color; /* NULL; filled in by the setup code if
 746                            * color is enabled */
 747};
 748
 749struct diff_words_style {
 750        enum diff_words_type type;
 751        struct diff_words_style_elem new, old, ctx;
 752        const char *newline;
 753};
 754
 755static struct diff_words_style diff_words_styles[] = {
 756        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 757        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 758        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 759};
 760
 761struct diff_words_data {
 762        struct diff_words_buffer minus, plus;
 763        const char *current_plus;
 764        int last_minus;
 765        struct diff_options *opt;
 766        regex_t *word_regex;
 767        enum diff_words_type type;
 768        struct diff_words_style *style;
 769};
 770
 771static int fn_out_diff_words_write_helper(FILE *fp,
 772                                          struct diff_words_style_elem *st_el,
 773                                          const char *newline,
 774                                          size_t count, const char *buf,
 775                                          const char *line_prefix)
 776{
 777        int print = 0;
 778
 779        while (count) {
 780                char *p = memchr(buf, '\n', count);
 781                if (print)
 782                        fputs(line_prefix, fp);
 783                if (p != buf) {
 784                        if (st_el->color && fputs(st_el->color, fp) < 0)
 785                                return -1;
 786                        if (fputs(st_el->prefix, fp) < 0 ||
 787                            fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 788                            fputs(st_el->suffix, fp) < 0)
 789                                return -1;
 790                        if (st_el->color && *st_el->color
 791                            && fputs(GIT_COLOR_RESET, fp) < 0)
 792                                return -1;
 793                }
 794                if (!p)
 795                        return 0;
 796                if (fputs(newline, fp) < 0)
 797                        return -1;
 798                count -= p + 1 - buf;
 799                buf = p + 1;
 800                print = 1;
 801        }
 802        return 0;
 803}
 804
 805/*
 806 * '--color-words' algorithm can be described as:
 807 *
 808 *   1. collect a the minus/plus lines of a diff hunk, divided into
 809 *      minus-lines and plus-lines;
 810 *
 811 *   2. break both minus-lines and plus-lines into words and
 812 *      place them into two mmfile_t with one word for each line;
 813 *
 814 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 815 *
 816 * And for the common parts of the both file, we output the plus side text.
 817 * diff_words->current_plus is used to trace the current position of the plus file
 818 * which printed. diff_words->last_minus is used to trace the last minus word
 819 * printed.
 820 *
 821 * For '--graph' to work with '--color-words', we need to output the graph prefix
 822 * on each line of color words output. Generally, there are two conditions on
 823 * which we should output the prefix.
 824 *
 825 *   1. diff_words->last_minus == 0 &&
 826 *      diff_words->current_plus == diff_words->plus.text.ptr
 827 *
 828 *      that is: the plus text must start as a new line, and if there is no minus
 829 *      word printed, a graph prefix must be printed.
 830 *
 831 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 832 *      *(diff_words->current_plus - 1) == '\n'
 833 *
 834 *      that is: a graph prefix must be printed following a '\n'
 835 */
 836static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 837{
 838        if ((diff_words->last_minus == 0 &&
 839                diff_words->current_plus == diff_words->plus.text.ptr) ||
 840                (diff_words->current_plus > diff_words->plus.text.ptr &&
 841                *(diff_words->current_plus - 1) == '\n')) {
 842                return 1;
 843        } else {
 844                return 0;
 845        }
 846}
 847
 848static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 849{
 850        struct diff_words_data *diff_words = priv;
 851        struct diff_words_style *style = diff_words->style;
 852        int minus_first, minus_len, plus_first, plus_len;
 853        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 854        struct diff_options *opt = diff_words->opt;
 855        const char *line_prefix;
 856
 857        if (line[0] != '@' || parse_hunk_header(line, len,
 858                        &minus_first, &minus_len, &plus_first, &plus_len))
 859                return;
 860
 861        assert(opt);
 862        line_prefix = diff_line_prefix(opt);
 863
 864        /* POSIX requires that first be decremented by one if len == 0... */
 865        if (minus_len) {
 866                minus_begin = diff_words->minus.orig[minus_first].begin;
 867                minus_end =
 868                        diff_words->minus.orig[minus_first + minus_len - 1].end;
 869        } else
 870                minus_begin = minus_end =
 871                        diff_words->minus.orig[minus_first].end;
 872
 873        if (plus_len) {
 874                plus_begin = diff_words->plus.orig[plus_first].begin;
 875                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 876        } else
 877                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 878
 879        if (color_words_output_graph_prefix(diff_words)) {
 880                fputs(line_prefix, diff_words->opt->file);
 881        }
 882        if (diff_words->current_plus != plus_begin) {
 883                fn_out_diff_words_write_helper(diff_words->opt->file,
 884                                &style->ctx, style->newline,
 885                                plus_begin - diff_words->current_plus,
 886                                diff_words->current_plus, line_prefix);
 887                if (*(plus_begin - 1) == '\n')
 888                        fputs(line_prefix, diff_words->opt->file);
 889        }
 890        if (minus_begin != minus_end) {
 891                fn_out_diff_words_write_helper(diff_words->opt->file,
 892                                &style->old, style->newline,
 893                                minus_end - minus_begin, minus_begin,
 894                                line_prefix);
 895        }
 896        if (plus_begin != plus_end) {
 897                fn_out_diff_words_write_helper(diff_words->opt->file,
 898                                &style->new, style->newline,
 899                                plus_end - plus_begin, plus_begin,
 900                                line_prefix);
 901        }
 902
 903        diff_words->current_plus = plus_end;
 904        diff_words->last_minus = minus_first;
 905}
 906
 907/* This function starts looking at *begin, and returns 0 iff a word was found. */
 908static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 909                int *begin, int *end)
 910{
 911        if (word_regex && *begin < buffer->size) {
 912                regmatch_t match[1];
 913                if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 914                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 915                                        '\n', match[0].rm_eo - match[0].rm_so);
 916                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 917                        *begin += match[0].rm_so;
 918                        return *begin >= *end;
 919                }
 920                return -1;
 921        }
 922
 923        /* find the next word */
 924        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 925                (*begin)++;
 926        if (*begin >= buffer->size)
 927                return -1;
 928
 929        /* find the end of the word */
 930        *end = *begin + 1;
 931        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 932                (*end)++;
 933
 934        return 0;
 935}
 936
 937/*
 938 * This function splits the words in buffer->text, stores the list with
 939 * newline separator into out, and saves the offsets of the original words
 940 * in buffer->orig.
 941 */
 942static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 943                regex_t *word_regex)
 944{
 945        int i, j;
 946        long alloc = 0;
 947
 948        out->size = 0;
 949        out->ptr = NULL;
 950
 951        /* fake an empty "0th" word */
 952        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 953        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 954        buffer->orig_nr = 1;
 955
 956        for (i = 0; i < buffer->text.size; i++) {
 957                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 958                        return;
 959
 960                /* store original boundaries */
 961                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
 962                                buffer->orig_alloc);
 963                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
 964                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
 965                buffer->orig_nr++;
 966
 967                /* store one word */
 968                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
 969                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
 970                out->ptr[out->size + j - i] = '\n';
 971                out->size += j - i + 1;
 972
 973                i = j - 1;
 974        }
 975}
 976
 977/* this executes the word diff on the accumulated buffers */
 978static void diff_words_show(struct diff_words_data *diff_words)
 979{
 980        xpparam_t xpp;
 981        xdemitconf_t xecfg;
 982        mmfile_t minus, plus;
 983        struct diff_words_style *style = diff_words->style;
 984
 985        struct diff_options *opt = diff_words->opt;
 986        const char *line_prefix;
 987
 988        assert(opt);
 989        line_prefix = diff_line_prefix(opt);
 990
 991        /* special case: only removal */
 992        if (!diff_words->plus.text.size) {
 993                fputs(line_prefix, diff_words->opt->file);
 994                fn_out_diff_words_write_helper(diff_words->opt->file,
 995                        &style->old, style->newline,
 996                        diff_words->minus.text.size,
 997                        diff_words->minus.text.ptr, line_prefix);
 998                diff_words->minus.text.size = 0;
 999                return;
1000        }
1001
1002        diff_words->current_plus = diff_words->plus.text.ptr;
1003        diff_words->last_minus = 0;
1004
1005        memset(&xpp, 0, sizeof(xpp));
1006        memset(&xecfg, 0, sizeof(xecfg));
1007        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1008        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1009        xpp.flags = 0;
1010        /* as only the hunk header will be parsed, we need a 0-context */
1011        xecfg.ctxlen = 0;
1012        xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1013                      &xpp, &xecfg);
1014        free(minus.ptr);
1015        free(plus.ptr);
1016        if (diff_words->current_plus != diff_words->plus.text.ptr +
1017                        diff_words->plus.text.size) {
1018                if (color_words_output_graph_prefix(diff_words))
1019                        fputs(line_prefix, diff_words->opt->file);
1020                fn_out_diff_words_write_helper(diff_words->opt->file,
1021                        &style->ctx, style->newline,
1022                        diff_words->plus.text.ptr + diff_words->plus.text.size
1023                        - diff_words->current_plus, diff_words->current_plus,
1024                        line_prefix);
1025        }
1026        diff_words->minus.text.size = diff_words->plus.text.size = 0;
1027}
1028
1029/* In "color-words" mode, show word-diff of words accumulated in the buffer */
1030static void diff_words_flush(struct emit_callback *ecbdata)
1031{
1032        if (ecbdata->diff_words->minus.text.size ||
1033            ecbdata->diff_words->plus.text.size)
1034                diff_words_show(ecbdata->diff_words);
1035}
1036
1037static void diff_filespec_load_driver(struct diff_filespec *one)
1038{
1039        /* Use already-loaded driver */
1040        if (one->driver)
1041                return;
1042
1043        if (S_ISREG(one->mode))
1044                one->driver = userdiff_find_by_path(one->path);
1045
1046        /* Fallback to default settings */
1047        if (!one->driver)
1048                one->driver = userdiff_find_by_name("default");
1049}
1050
1051static const char *userdiff_word_regex(struct diff_filespec *one)
1052{
1053        diff_filespec_load_driver(one);
1054        return one->driver->word_regex;
1055}
1056
1057static void init_diff_words_data(struct emit_callback *ecbdata,
1058                                 struct diff_options *orig_opts,
1059                                 struct diff_filespec *one,
1060                                 struct diff_filespec *two)
1061{
1062        int i;
1063        struct diff_options *o = xmalloc(sizeof(struct diff_options));
1064        memcpy(o, orig_opts, sizeof(struct diff_options));
1065
1066        ecbdata->diff_words =
1067                xcalloc(1, sizeof(struct diff_words_data));
1068        ecbdata->diff_words->type = o->word_diff;
1069        ecbdata->diff_words->opt = o;
1070        if (!o->word_regex)
1071                o->word_regex = userdiff_word_regex(one);
1072        if (!o->word_regex)
1073                o->word_regex = userdiff_word_regex(two);
1074        if (!o->word_regex)
1075                o->word_regex = diff_word_regex_cfg;
1076        if (o->word_regex) {
1077                ecbdata->diff_words->word_regex = (regex_t *)
1078                        xmalloc(sizeof(regex_t));
1079                if (regcomp(ecbdata->diff_words->word_regex,
1080                            o->word_regex,
1081                            REG_EXTENDED | REG_NEWLINE))
1082                        die ("Invalid regular expression: %s",
1083                             o->word_regex);
1084        }
1085        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1086                if (o->word_diff == diff_words_styles[i].type) {
1087                        ecbdata->diff_words->style =
1088                                &diff_words_styles[i];
1089                        break;
1090                }
1091        }
1092        if (want_color(o->use_color)) {
1093                struct diff_words_style *st = ecbdata->diff_words->style;
1094                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1095                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1096                st->ctx.color = diff_get_color_opt(o, DIFF_PLAIN);
1097        }
1098}
1099
1100static void free_diff_words_data(struct emit_callback *ecbdata)
1101{
1102        if (ecbdata->diff_words) {
1103                diff_words_flush(ecbdata);
1104                free (ecbdata->diff_words->opt);
1105                free (ecbdata->diff_words->minus.text.ptr);
1106                free (ecbdata->diff_words->minus.orig);
1107                free (ecbdata->diff_words->plus.text.ptr);
1108                free (ecbdata->diff_words->plus.orig);
1109                if (ecbdata->diff_words->word_regex) {
1110                        regfree(ecbdata->diff_words->word_regex);
1111                        free(ecbdata->diff_words->word_regex);
1112                }
1113                free(ecbdata->diff_words);
1114                ecbdata->diff_words = NULL;
1115        }
1116}
1117
1118const char *diff_get_color(int diff_use_color, enum color_diff ix)
1119{
1120        if (want_color(diff_use_color))
1121                return diff_colors[ix];
1122        return "";
1123}
1124
1125const char *diff_line_prefix(struct diff_options *opt)
1126{
1127        struct strbuf *msgbuf;
1128        if (!opt->output_prefix)
1129                return "";
1130
1131        msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1132        return msgbuf->buf;
1133}
1134
1135static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1136{
1137        const char *cp;
1138        unsigned long allot;
1139        size_t l = len;
1140
1141        if (ecb->truncate)
1142                return ecb->truncate(line, len);
1143        cp = line;
1144        allot = l;
1145        while (0 < l) {
1146                (void) utf8_width(&cp, &l);
1147                if (!cp)
1148                        break; /* truncated in the middle? */
1149        }
1150        return allot - l;
1151}
1152
1153static void find_lno(const char *line, struct emit_callback *ecbdata)
1154{
1155        const char *p;
1156        ecbdata->lno_in_preimage = 0;
1157        ecbdata->lno_in_postimage = 0;
1158        p = strchr(line, '-');
1159        if (!p)
1160                return; /* cannot happen */
1161        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1162        p = strchr(p, '+');
1163        if (!p)
1164                return; /* cannot happen */
1165        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1166}
1167
1168static void fn_out_consume(void *priv, char *line, unsigned long len)
1169{
1170        struct emit_callback *ecbdata = priv;
1171        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1172        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
1173        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1174        struct diff_options *o = ecbdata->opt;
1175        const char *line_prefix = diff_line_prefix(o);
1176
1177        if (ecbdata->header) {
1178                fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1179                strbuf_reset(ecbdata->header);
1180                ecbdata->header = NULL;
1181        }
1182        *(ecbdata->found_changesp) = 1;
1183
1184        if (ecbdata->label_path[0]) {
1185                const char *name_a_tab, *name_b_tab;
1186
1187                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1188                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1189
1190                fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1191                        line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1192                fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1193                        line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1194                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1195        }
1196
1197        if (diff_suppress_blank_empty
1198            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1199                line[0] = '\n';
1200                len = 1;
1201        }
1202
1203        if (line[0] == '@') {
1204                if (ecbdata->diff_words)
1205                        diff_words_flush(ecbdata);
1206                len = sane_truncate_line(ecbdata, line, len);
1207                find_lno(line, ecbdata);
1208                emit_hunk_header(ecbdata, line, len);
1209                if (line[len-1] != '\n')
1210                        putc('\n', ecbdata->opt->file);
1211                return;
1212        }
1213
1214        if (len < 1) {
1215                emit_line(ecbdata->opt, reset, reset, line, len);
1216                if (ecbdata->diff_words
1217                    && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1218                        fputs("~\n", ecbdata->opt->file);
1219                return;
1220        }
1221
1222        if (ecbdata->diff_words) {
1223                if (line[0] == '-') {
1224                        diff_words_append(line, len,
1225                                          &ecbdata->diff_words->minus);
1226                        return;
1227                } else if (line[0] == '+') {
1228                        diff_words_append(line, len,
1229                                          &ecbdata->diff_words->plus);
1230                        return;
1231                } else if (starts_with(line, "\\ ")) {
1232                        /*
1233                         * Eat the "no newline at eof" marker as if we
1234                         * saw a "+" or "-" line with nothing on it,
1235                         * and return without diff_words_flush() to
1236                         * defer processing. If this is the end of
1237                         * preimage, more "+" lines may come after it.
1238                         */
1239                        return;
1240                }
1241                diff_words_flush(ecbdata);
1242                if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1243                        emit_line(ecbdata->opt, plain, reset, line, len);
1244                        fputs("~\n", ecbdata->opt->file);
1245                } else {
1246                        /*
1247                         * Skip the prefix character, if any.  With
1248                         * diff_suppress_blank_empty, there may be
1249                         * none.
1250                         */
1251                        if (line[0] != '\n') {
1252                              line++;
1253                              len--;
1254                        }
1255                        emit_line(ecbdata->opt, plain, reset, line, len);
1256                }
1257                return;
1258        }
1259
1260        if (line[0] != '+') {
1261                const char *color =
1262                        diff_get_color(ecbdata->color_diff,
1263                                       line[0] == '-' ? DIFF_FILE_OLD : DIFF_PLAIN);
1264                ecbdata->lno_in_preimage++;
1265                if (line[0] == ' ')
1266                        ecbdata->lno_in_postimage++;
1267                emit_line(ecbdata->opt, color, reset, line, len);
1268        } else {
1269                ecbdata->lno_in_postimage++;
1270                emit_add_line(reset, ecbdata, line + 1, len - 1);
1271        }
1272}
1273
1274static char *pprint_rename(const char *a, const char *b)
1275{
1276        const char *old = a;
1277        const char *new = b;
1278        struct strbuf name = STRBUF_INIT;
1279        int pfx_length, sfx_length;
1280        int pfx_adjust_for_slash;
1281        int len_a = strlen(a);
1282        int len_b = strlen(b);
1283        int a_midlen, b_midlen;
1284        int qlen_a = quote_c_style(a, NULL, NULL, 0);
1285        int qlen_b = quote_c_style(b, NULL, NULL, 0);
1286
1287        if (qlen_a || qlen_b) {
1288                quote_c_style(a, &name, NULL, 0);
1289                strbuf_addstr(&name, " => ");
1290                quote_c_style(b, &name, NULL, 0);
1291                return strbuf_detach(&name, NULL);
1292        }
1293
1294        /* Find common prefix */
1295        pfx_length = 0;
1296        while (*old && *new && *old == *new) {
1297                if (*old == '/')
1298                        pfx_length = old - a + 1;
1299                old++;
1300                new++;
1301        }
1302
1303        /* Find common suffix */
1304        old = a + len_a;
1305        new = b + len_b;
1306        sfx_length = 0;
1307        /*
1308         * If there is a common prefix, it must end in a slash.  In
1309         * that case we let this loop run 1 into the prefix to see the
1310         * same slash.
1311         *
1312         * If there is no common prefix, we cannot do this as it would
1313         * underrun the input strings.
1314         */
1315        pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1316        while (a + pfx_length - pfx_adjust_for_slash <= old &&
1317               b + pfx_length - pfx_adjust_for_slash <= new &&
1318               *old == *new) {
1319                if (*old == '/')
1320                        sfx_length = len_a - (old - a);
1321                old--;
1322                new--;
1323        }
1324
1325        /*
1326         * pfx{mid-a => mid-b}sfx
1327         * {pfx-a => pfx-b}sfx
1328         * pfx{sfx-a => sfx-b}
1329         * name-a => name-b
1330         */
1331        a_midlen = len_a - pfx_length - sfx_length;
1332        b_midlen = len_b - pfx_length - sfx_length;
1333        if (a_midlen < 0)
1334                a_midlen = 0;
1335        if (b_midlen < 0)
1336                b_midlen = 0;
1337
1338        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1339        if (pfx_length + sfx_length) {
1340                strbuf_add(&name, a, pfx_length);
1341                strbuf_addch(&name, '{');
1342        }
1343        strbuf_add(&name, a + pfx_length, a_midlen);
1344        strbuf_addstr(&name, " => ");
1345        strbuf_add(&name, b + pfx_length, b_midlen);
1346        if (pfx_length + sfx_length) {
1347                strbuf_addch(&name, '}');
1348                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1349        }
1350        return strbuf_detach(&name, NULL);
1351}
1352
1353struct diffstat_t {
1354        int nr;
1355        int alloc;
1356        struct diffstat_file {
1357                char *from_name;
1358                char *name;
1359                char *print_name;
1360                unsigned is_unmerged:1;
1361                unsigned is_binary:1;
1362                unsigned is_renamed:1;
1363                unsigned is_interesting:1;
1364                uintmax_t added, deleted;
1365        } **files;
1366};
1367
1368static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1369                                          const char *name_a,
1370                                          const char *name_b)
1371{
1372        struct diffstat_file *x;
1373        x = xcalloc(1, sizeof(*x));
1374        ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
1375        diffstat->files[diffstat->nr++] = x;
1376        if (name_b) {
1377                x->from_name = xstrdup(name_a);
1378                x->name = xstrdup(name_b);
1379                x->is_renamed = 1;
1380        }
1381        else {
1382                x->from_name = NULL;
1383                x->name = xstrdup(name_a);
1384        }
1385        return x;
1386}
1387
1388static void diffstat_consume(void *priv, char *line, unsigned long len)
1389{
1390        struct diffstat_t *diffstat = priv;
1391        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1392
1393        if (line[0] == '+')
1394                x->added++;
1395        else if (line[0] == '-')
1396                x->deleted++;
1397}
1398
1399const char mime_boundary_leader[] = "------------";
1400
1401static int scale_linear(int it, int width, int max_change)
1402{
1403        if (!it)
1404                return 0;
1405        /*
1406         * make sure that at least one '-' or '+' is printed if
1407         * there is any change to this path. The easiest way is to
1408         * scale linearly as if the alloted width is one column shorter
1409         * than it is, and then add 1 to the result.
1410         */
1411        return 1 + (it * (width - 1) / max_change);
1412}
1413
1414static void show_name(FILE *file,
1415                      const char *prefix, const char *name, int len)
1416{
1417        fprintf(file, " %s%-*s |", prefix, len, name);
1418}
1419
1420static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1421{
1422        if (cnt <= 0)
1423                return;
1424        fprintf(file, "%s", set);
1425        while (cnt--)
1426                putc(ch, file);
1427        fprintf(file, "%s", reset);
1428}
1429
1430static void fill_print_name(struct diffstat_file *file)
1431{
1432        char *pname;
1433
1434        if (file->print_name)
1435                return;
1436
1437        if (!file->is_renamed) {
1438                struct strbuf buf = STRBUF_INIT;
1439                if (quote_c_style(file->name, &buf, NULL, 0)) {
1440                        pname = strbuf_detach(&buf, NULL);
1441                } else {
1442                        pname = file->name;
1443                        strbuf_release(&buf);
1444                }
1445        } else {
1446                pname = pprint_rename(file->from_name, file->name);
1447        }
1448        file->print_name = pname;
1449}
1450
1451int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1452{
1453        struct strbuf sb = STRBUF_INIT;
1454        int ret;
1455
1456        if (!files) {
1457                assert(insertions == 0 && deletions == 0);
1458                return fprintf(fp, "%s\n", " 0 files changed");
1459        }
1460
1461        strbuf_addf(&sb,
1462                    (files == 1) ? " %d file changed" : " %d files changed",
1463                    files);
1464
1465        /*
1466         * For binary diff, the caller may want to print "x files
1467         * changed" with insertions == 0 && deletions == 0.
1468         *
1469         * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1470         * is probably less confusing (i.e skip over "2 files changed
1471         * but nothing about added/removed lines? Is this a bug in Git?").
1472         */
1473        if (insertions || deletions == 0) {
1474                strbuf_addf(&sb,
1475                            (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1476                            insertions);
1477        }
1478
1479        if (deletions || insertions == 0) {
1480                strbuf_addf(&sb,
1481                            (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1482                            deletions);
1483        }
1484        strbuf_addch(&sb, '\n');
1485        ret = fputs(sb.buf, fp);
1486        strbuf_release(&sb);
1487        return ret;
1488}
1489
1490static void show_stats(struct diffstat_t *data, struct diff_options *options)
1491{
1492        int i, len, add, del, adds = 0, dels = 0;
1493        uintmax_t max_change = 0, max_len = 0;
1494        int total_files = data->nr, count;
1495        int width, name_width, graph_width, number_width = 0, bin_width = 0;
1496        const char *reset, *add_c, *del_c;
1497        const char *line_prefix = "";
1498        int extra_shown = 0;
1499
1500        if (data->nr == 0)
1501                return;
1502
1503        line_prefix = diff_line_prefix(options);
1504        count = options->stat_count ? options->stat_count : data->nr;
1505
1506        reset = diff_get_color_opt(options, DIFF_RESET);
1507        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1508        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1509
1510        /*
1511         * Find the longest filename and max number of changes
1512         */
1513        for (i = 0; (i < count) && (i < data->nr); i++) {
1514                struct diffstat_file *file = data->files[i];
1515                uintmax_t change = file->added + file->deleted;
1516
1517                if (!file->is_interesting && (change == 0)) {
1518                        count++; /* not shown == room for one more */
1519                        continue;
1520                }
1521                fill_print_name(file);
1522                len = strlen(file->print_name);
1523                if (max_len < len)
1524                        max_len = len;
1525
1526                if (file->is_unmerged) {
1527                        /* "Unmerged" is 8 characters */
1528                        bin_width = bin_width < 8 ? 8 : bin_width;
1529                        continue;
1530                }
1531                if (file->is_binary) {
1532                        /* "Bin XXX -> YYY bytes" */
1533                        int w = 14 + decimal_width(file->added)
1534                                + decimal_width(file->deleted);
1535                        bin_width = bin_width < w ? w : bin_width;
1536                        /* Display change counts aligned with "Bin" */
1537                        number_width = 3;
1538                        continue;
1539                }
1540
1541                if (max_change < change)
1542                        max_change = change;
1543        }
1544        count = i; /* where we can stop scanning in data->files[] */
1545
1546        /*
1547         * We have width = stat_width or term_columns() columns total.
1548         * We want a maximum of min(max_len, stat_name_width) for the name part.
1549         * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1550         * We also need 1 for " " and 4 + decimal_width(max_change)
1551         * for " | NNNN " and one the empty column at the end, altogether
1552         * 6 + decimal_width(max_change).
1553         *
1554         * If there's not enough space, we will use the smaller of
1555         * stat_name_width (if set) and 5/8*width for the filename,
1556         * and the rest for constant elements + graph part, but no more
1557         * than stat_graph_width for the graph part.
1558         * (5/8 gives 50 for filename and 30 for the constant parts + graph
1559         * for the standard terminal size).
1560         *
1561         * In other words: stat_width limits the maximum width, and
1562         * stat_name_width fixes the maximum width of the filename,
1563         * and is also used to divide available columns if there
1564         * aren't enough.
1565         *
1566         * Binary files are displayed with "Bin XXX -> YYY bytes"
1567         * instead of the change count and graph. This part is treated
1568         * similarly to the graph part, except that it is not
1569         * "scaled". If total width is too small to accommodate the
1570         * guaranteed minimum width of the filename part and the
1571         * separators and this message, this message will "overflow"
1572         * making the line longer than the maximum width.
1573         */
1574
1575        if (options->stat_width == -1)
1576                width = term_columns() - options->output_prefix_length;
1577        else
1578                width = options->stat_width ? options->stat_width : 80;
1579        number_width = decimal_width(max_change) > number_width ?
1580                decimal_width(max_change) : number_width;
1581
1582        if (options->stat_graph_width == -1)
1583                options->stat_graph_width = diff_stat_graph_width;
1584
1585        /*
1586         * Guarantee 3/8*16==6 for the graph part
1587         * and 5/8*16==10 for the filename part
1588         */
1589        if (width < 16 + 6 + number_width)
1590                width = 16 + 6 + number_width;
1591
1592        /*
1593         * First assign sizes that are wanted, ignoring available width.
1594         * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1595         * starting from "XXX" should fit in graph_width.
1596         */
1597        graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1598        if (options->stat_graph_width &&
1599            options->stat_graph_width < graph_width)
1600                graph_width = options->stat_graph_width;
1601
1602        name_width = (options->stat_name_width > 0 &&
1603                      options->stat_name_width < max_len) ?
1604                options->stat_name_width : max_len;
1605
1606        /*
1607         * Adjust adjustable widths not to exceed maximum width
1608         */
1609        if (name_width + number_width + 6 + graph_width > width) {
1610                if (graph_width > width * 3/8 - number_width - 6) {
1611                        graph_width = width * 3/8 - number_width - 6;
1612                        if (graph_width < 6)
1613                                graph_width = 6;
1614                }
1615
1616                if (options->stat_graph_width &&
1617                    graph_width > options->stat_graph_width)
1618                        graph_width = options->stat_graph_width;
1619                if (name_width > width - number_width - 6 - graph_width)
1620                        name_width = width - number_width - 6 - graph_width;
1621                else
1622                        graph_width = width - number_width - 6 - name_width;
1623        }
1624
1625        /*
1626         * From here name_width is the width of the name area,
1627         * and graph_width is the width of the graph area.
1628         * max_change is used to scale graph properly.
1629         */
1630        for (i = 0; i < count; i++) {
1631                const char *prefix = "";
1632                struct diffstat_file *file = data->files[i];
1633                char *name = file->print_name;
1634                uintmax_t added = file->added;
1635                uintmax_t deleted = file->deleted;
1636                int name_len;
1637
1638                if (!file->is_interesting && (added + deleted == 0))
1639                        continue;
1640
1641                /*
1642                 * "scale" the filename
1643                 */
1644                len = name_width;
1645                name_len = strlen(name);
1646                if (name_width < name_len) {
1647                        char *slash;
1648                        prefix = "...";
1649                        len -= 3;
1650                        name += name_len - len;
1651                        slash = strchr(name, '/');
1652                        if (slash)
1653                                name = slash;
1654                }
1655
1656                if (file->is_binary) {
1657                        fprintf(options->file, "%s", line_prefix);
1658                        show_name(options->file, prefix, name, len);
1659                        fprintf(options->file, " %*s", number_width, "Bin");
1660                        if (!added && !deleted) {
1661                                putc('\n', options->file);
1662                                continue;
1663                        }
1664                        fprintf(options->file, " %s%"PRIuMAX"%s",
1665                                del_c, deleted, reset);
1666                        fprintf(options->file, " -> ");
1667                        fprintf(options->file, "%s%"PRIuMAX"%s",
1668                                add_c, added, reset);
1669                        fprintf(options->file, " bytes");
1670                        fprintf(options->file, "\n");
1671                        continue;
1672                }
1673                else if (file->is_unmerged) {
1674                        fprintf(options->file, "%s", line_prefix);
1675                        show_name(options->file, prefix, name, len);
1676                        fprintf(options->file, " Unmerged\n");
1677                        continue;
1678                }
1679
1680                /*
1681                 * scale the add/delete
1682                 */
1683                add = added;
1684                del = deleted;
1685
1686                if (graph_width <= max_change) {
1687                        int total = scale_linear(add + del, graph_width, max_change);
1688                        if (total < 2 && add && del)
1689                                /* width >= 2 due to the sanity check */
1690                                total = 2;
1691                        if (add < del) {
1692                                add = scale_linear(add, graph_width, max_change);
1693                                del = total - add;
1694                        } else {
1695                                del = scale_linear(del, graph_width, max_change);
1696                                add = total - del;
1697                        }
1698                }
1699                fprintf(options->file, "%s", line_prefix);
1700                show_name(options->file, prefix, name, len);
1701                fprintf(options->file, " %*"PRIuMAX"%s",
1702                        number_width, added + deleted,
1703                        added + deleted ? " " : "");
1704                show_graph(options->file, '+', add, add_c, reset);
1705                show_graph(options->file, '-', del, del_c, reset);
1706                fprintf(options->file, "\n");
1707        }
1708
1709        for (i = 0; i < data->nr; i++) {
1710                struct diffstat_file *file = data->files[i];
1711                uintmax_t added = file->added;
1712                uintmax_t deleted = file->deleted;
1713
1714                if (file->is_unmerged ||
1715                    (!file->is_interesting && (added + deleted == 0))) {
1716                        total_files--;
1717                        continue;
1718                }
1719
1720                if (!file->is_binary) {
1721                        adds += added;
1722                        dels += deleted;
1723                }
1724                if (i < count)
1725                        continue;
1726                if (!extra_shown)
1727                        fprintf(options->file, "%s ...\n", line_prefix);
1728                extra_shown = 1;
1729        }
1730        fprintf(options->file, "%s", line_prefix);
1731        print_stat_summary(options->file, total_files, adds, dels);
1732}
1733
1734static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1735{
1736        int i, adds = 0, dels = 0, total_files = data->nr;
1737
1738        if (data->nr == 0)
1739                return;
1740
1741        for (i = 0; i < data->nr; i++) {
1742                int added = data->files[i]->added;
1743                int deleted= data->files[i]->deleted;
1744
1745                if (data->files[i]->is_unmerged ||
1746                    (!data->files[i]->is_interesting && (added + deleted == 0))) {
1747                        total_files--;
1748                } else if (!data->files[i]->is_binary) { /* don't count bytes */
1749                        adds += added;
1750                        dels += deleted;
1751                }
1752        }
1753        fprintf(options->file, "%s", diff_line_prefix(options));
1754        print_stat_summary(options->file, total_files, adds, dels);
1755}
1756
1757static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1758{
1759        int i;
1760
1761        if (data->nr == 0)
1762                return;
1763
1764        for (i = 0; i < data->nr; i++) {
1765                struct diffstat_file *file = data->files[i];
1766
1767                fprintf(options->file, "%s", diff_line_prefix(options));
1768
1769                if (file->is_binary)
1770                        fprintf(options->file, "-\t-\t");
1771                else
1772                        fprintf(options->file,
1773                                "%"PRIuMAX"\t%"PRIuMAX"\t",
1774                                file->added, file->deleted);
1775                if (options->line_termination) {
1776                        fill_print_name(file);
1777                        if (!file->is_renamed)
1778                                write_name_quoted(file->name, options->file,
1779                                                  options->line_termination);
1780                        else {
1781                                fputs(file->print_name, options->file);
1782                                putc(options->line_termination, options->file);
1783                        }
1784                } else {
1785                        if (file->is_renamed) {
1786                                putc('\0', options->file);
1787                                write_name_quoted(file->from_name, options->file, '\0');
1788                        }
1789                        write_name_quoted(file->name, options->file, '\0');
1790                }
1791        }
1792}
1793
1794struct dirstat_file {
1795        const char *name;
1796        unsigned long changed;
1797};
1798
1799struct dirstat_dir {
1800        struct dirstat_file *files;
1801        int alloc, nr, permille, cumulative;
1802};
1803
1804static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1805                unsigned long changed, const char *base, int baselen)
1806{
1807        unsigned long this_dir = 0;
1808        unsigned int sources = 0;
1809        const char *line_prefix = diff_line_prefix(opt);
1810
1811        while (dir->nr) {
1812                struct dirstat_file *f = dir->files;
1813                int namelen = strlen(f->name);
1814                unsigned long this;
1815                char *slash;
1816
1817                if (namelen < baselen)
1818                        break;
1819                if (memcmp(f->name, base, baselen))
1820                        break;
1821                slash = strchr(f->name + baselen, '/');
1822                if (slash) {
1823                        int newbaselen = slash + 1 - f->name;
1824                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1825                        sources++;
1826                } else {
1827                        this = f->changed;
1828                        dir->files++;
1829                        dir->nr--;
1830                        sources += 2;
1831                }
1832                this_dir += this;
1833        }
1834
1835        /*
1836         * We don't report dirstat's for
1837         *  - the top level
1838         *  - or cases where everything came from a single directory
1839         *    under this directory (sources == 1).
1840         */
1841        if (baselen && sources != 1) {
1842                if (this_dir) {
1843                        int permille = this_dir * 1000 / changed;
1844                        if (permille >= dir->permille) {
1845                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1846                                        permille / 10, permille % 10, baselen, base);
1847                                if (!dir->cumulative)
1848                                        return 0;
1849                        }
1850                }
1851        }
1852        return this_dir;
1853}
1854
1855static int dirstat_compare(const void *_a, const void *_b)
1856{
1857        const struct dirstat_file *a = _a;
1858        const struct dirstat_file *b = _b;
1859        return strcmp(a->name, b->name);
1860}
1861
1862static void show_dirstat(struct diff_options *options)
1863{
1864        int i;
1865        unsigned long changed;
1866        struct dirstat_dir dir;
1867        struct diff_queue_struct *q = &diff_queued_diff;
1868
1869        dir.files = NULL;
1870        dir.alloc = 0;
1871        dir.nr = 0;
1872        dir.permille = options->dirstat_permille;
1873        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1874
1875        changed = 0;
1876        for (i = 0; i < q->nr; i++) {
1877                struct diff_filepair *p = q->queue[i];
1878                const char *name;
1879                unsigned long copied, added, damage;
1880                int content_changed;
1881
1882                name = p->two->path ? p->two->path : p->one->path;
1883
1884                if (p->one->sha1_valid && p->two->sha1_valid)
1885                        content_changed = hashcmp(p->one->sha1, p->two->sha1);
1886                else
1887                        content_changed = 1;
1888
1889                if (!content_changed) {
1890                        /*
1891                         * The SHA1 has not changed, so pre-/post-content is
1892                         * identical. We can therefore skip looking at the
1893                         * file contents altogether.
1894                         */
1895                        damage = 0;
1896                        goto found_damage;
1897                }
1898
1899                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1900                        /*
1901                         * In --dirstat-by-file mode, we don't really need to
1902                         * look at the actual file contents at all.
1903                         * The fact that the SHA1 changed is enough for us to
1904                         * add this file to the list of results
1905                         * (with each file contributing equal damage).
1906                         */
1907                        damage = 1;
1908                        goto found_damage;
1909                }
1910
1911                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1912                        diff_populate_filespec(p->one, 0);
1913                        diff_populate_filespec(p->two, 0);
1914                        diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1915                                               &copied, &added);
1916                        diff_free_filespec_data(p->one);
1917                        diff_free_filespec_data(p->two);
1918                } else if (DIFF_FILE_VALID(p->one)) {
1919                        diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
1920                        copied = added = 0;
1921                        diff_free_filespec_data(p->one);
1922                } else if (DIFF_FILE_VALID(p->two)) {
1923                        diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
1924                        copied = 0;
1925                        added = p->two->size;
1926                        diff_free_filespec_data(p->two);
1927                } else
1928                        continue;
1929
1930                /*
1931                 * Original minus copied is the removed material,
1932                 * added is the new material.  They are both damages
1933                 * made to the preimage.
1934                 * If the resulting damage is zero, we know that
1935                 * diffcore_count_changes() considers the two entries to
1936                 * be identical, but since content_changed is true, we
1937                 * know that there must have been _some_ kind of change,
1938                 * so we force all entries to have damage > 0.
1939                 */
1940                damage = (p->one->size - copied) + added;
1941                if (!damage)
1942                        damage = 1;
1943
1944found_damage:
1945                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1946                dir.files[dir.nr].name = name;
1947                dir.files[dir.nr].changed = damage;
1948                changed += damage;
1949                dir.nr++;
1950        }
1951
1952        /* This can happen even with many files, if everything was renames */
1953        if (!changed)
1954                return;
1955
1956        /* Show all directories with more than x% of the changes */
1957        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1958        gather_dirstat(options, &dir, changed, "", 0);
1959}
1960
1961static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
1962{
1963        int i;
1964        unsigned long changed;
1965        struct dirstat_dir dir;
1966
1967        if (data->nr == 0)
1968                return;
1969
1970        dir.files = NULL;
1971        dir.alloc = 0;
1972        dir.nr = 0;
1973        dir.permille = options->dirstat_permille;
1974        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1975
1976        changed = 0;
1977        for (i = 0; i < data->nr; i++) {
1978                struct diffstat_file *file = data->files[i];
1979                unsigned long damage = file->added + file->deleted;
1980                if (file->is_binary)
1981                        /*
1982                         * binary files counts bytes, not lines. Must find some
1983                         * way to normalize binary bytes vs. textual lines.
1984                         * The following heuristic assumes that there are 64
1985                         * bytes per "line".
1986                         * This is stupid and ugly, but very cheap...
1987                         */
1988                        damage = (damage + 63) / 64;
1989                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1990                dir.files[dir.nr].name = file->name;
1991                dir.files[dir.nr].changed = damage;
1992                changed += damage;
1993                dir.nr++;
1994        }
1995
1996        /* This can happen even with many files, if everything was renames */
1997        if (!changed)
1998                return;
1999
2000        /* Show all directories with more than x% of the changes */
2001        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
2002        gather_dirstat(options, &dir, changed, "", 0);
2003}
2004
2005static void free_diffstat_info(struct diffstat_t *diffstat)
2006{
2007        int i;
2008        for (i = 0; i < diffstat->nr; i++) {
2009                struct diffstat_file *f = diffstat->files[i];
2010                if (f->name != f->print_name)
2011                        free(f->print_name);
2012                free(f->name);
2013                free(f->from_name);
2014                free(f);
2015        }
2016        free(diffstat->files);
2017}
2018
2019struct checkdiff_t {
2020        const char *filename;
2021        int lineno;
2022        int conflict_marker_size;
2023        struct diff_options *o;
2024        unsigned ws_rule;
2025        unsigned status;
2026};
2027
2028static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2029{
2030        char firstchar;
2031        int cnt;
2032
2033        if (len < marker_size + 1)
2034                return 0;
2035        firstchar = line[0];
2036        switch (firstchar) {
2037        case '=': case '>': case '<': case '|':
2038                break;
2039        default:
2040                return 0;
2041        }
2042        for (cnt = 1; cnt < marker_size; cnt++)
2043                if (line[cnt] != firstchar)
2044                        return 0;
2045        /* line[1] thru line[marker_size-1] are same as firstchar */
2046        if (len < marker_size + 1 || !isspace(line[marker_size]))
2047                return 0;
2048        return 1;
2049}
2050
2051static void checkdiff_consume(void *priv, char *line, unsigned long len)
2052{
2053        struct checkdiff_t *data = priv;
2054        int marker_size = data->conflict_marker_size;
2055        const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2056        const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2057        const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2058        char *err;
2059        const char *line_prefix;
2060
2061        assert(data->o);
2062        line_prefix = diff_line_prefix(data->o);
2063
2064        if (line[0] == '+') {
2065                unsigned bad;
2066                data->lineno++;
2067                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2068                        data->status |= 1;
2069                        fprintf(data->o->file,
2070                                "%s%s:%d: leftover conflict marker\n",
2071                                line_prefix, data->filename, data->lineno);
2072                }
2073                bad = ws_check(line + 1, len - 1, data->ws_rule);
2074                if (!bad)
2075                        return;
2076                data->status |= bad;
2077                err = whitespace_error_string(bad);
2078                fprintf(data->o->file, "%s%s:%d: %s.\n",
2079                        line_prefix, data->filename, data->lineno, err);
2080                free(err);
2081                emit_line(data->o, set, reset, line, 1);
2082                ws_check_emit(line + 1, len - 1, data->ws_rule,
2083                              data->o->file, set, reset, ws);
2084        } else if (line[0] == ' ') {
2085                data->lineno++;
2086        } else if (line[0] == '@') {
2087                char *plus = strchr(line, '+');
2088                if (plus)
2089                        data->lineno = strtol(plus, NULL, 10) - 1;
2090                else
2091                        die("invalid diff");
2092        }
2093}
2094
2095static unsigned char *deflate_it(char *data,
2096                                 unsigned long size,
2097                                 unsigned long *result_size)
2098{
2099        int bound;
2100        unsigned char *deflated;
2101        git_zstream stream;
2102
2103        git_deflate_init(&stream, zlib_compression_level);
2104        bound = git_deflate_bound(&stream, size);
2105        deflated = xmalloc(bound);
2106        stream.next_out = deflated;
2107        stream.avail_out = bound;
2108
2109        stream.next_in = (unsigned char *)data;
2110        stream.avail_in = size;
2111        while (git_deflate(&stream, Z_FINISH) == Z_OK)
2112                ; /* nothing */
2113        git_deflate_end(&stream);
2114        *result_size = stream.total_out;
2115        return deflated;
2116}
2117
2118static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2119                                  const char *prefix)
2120{
2121        void *cp;
2122        void *delta;
2123        void *deflated;
2124        void *data;
2125        unsigned long orig_size;
2126        unsigned long delta_size;
2127        unsigned long deflate_size;
2128        unsigned long data_size;
2129
2130        /* We could do deflated delta, or we could do just deflated two,
2131         * whichever is smaller.
2132         */
2133        delta = NULL;
2134        deflated = deflate_it(two->ptr, two->size, &deflate_size);
2135        if (one->size && two->size) {
2136                delta = diff_delta(one->ptr, one->size,
2137                                   two->ptr, two->size,
2138                                   &delta_size, deflate_size);
2139                if (delta) {
2140                        void *to_free = delta;
2141                        orig_size = delta_size;
2142                        delta = deflate_it(delta, delta_size, &delta_size);
2143                        free(to_free);
2144                }
2145        }
2146
2147        if (delta && delta_size < deflate_size) {
2148                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2149                free(deflated);
2150                data = delta;
2151                data_size = delta_size;
2152        }
2153        else {
2154                fprintf(file, "%sliteral %lu\n", prefix, two->size);
2155                free(delta);
2156                data = deflated;
2157                data_size = deflate_size;
2158        }
2159
2160        /* emit data encoded in base85 */
2161        cp = data;
2162        while (data_size) {
2163                int bytes = (52 < data_size) ? 52 : data_size;
2164                char line[70];
2165                data_size -= bytes;
2166                if (bytes <= 26)
2167                        line[0] = bytes + 'A' - 1;
2168                else
2169                        line[0] = bytes - 26 + 'a' - 1;
2170                encode_85(line + 1, cp, bytes);
2171                cp = (char *) cp + bytes;
2172                fprintf(file, "%s", prefix);
2173                fputs(line, file);
2174                fputc('\n', file);
2175        }
2176        fprintf(file, "%s\n", prefix);
2177        free(data);
2178}
2179
2180static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2181                             const char *prefix)
2182{
2183        fprintf(file, "%sGIT binary patch\n", prefix);
2184        emit_binary_diff_body(file, one, two, prefix);
2185        emit_binary_diff_body(file, two, one, prefix);
2186}
2187
2188int diff_filespec_is_binary(struct diff_filespec *one)
2189{
2190        if (one->is_binary == -1) {
2191                diff_filespec_load_driver(one);
2192                if (one->driver->binary != -1)
2193                        one->is_binary = one->driver->binary;
2194                else {
2195                        if (!one->data && DIFF_FILE_VALID(one))
2196                                diff_populate_filespec(one, CHECK_BINARY);
2197                        if (one->is_binary == -1 && one->data)
2198                                one->is_binary = buffer_is_binary(one->data,
2199                                                one->size);
2200                        if (one->is_binary == -1)
2201                                one->is_binary = 0;
2202                }
2203        }
2204        return one->is_binary;
2205}
2206
2207static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2208{
2209        diff_filespec_load_driver(one);
2210        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2211}
2212
2213void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2214{
2215        if (!options->a_prefix)
2216                options->a_prefix = a;
2217        if (!options->b_prefix)
2218                options->b_prefix = b;
2219}
2220
2221struct userdiff_driver *get_textconv(struct diff_filespec *one)
2222{
2223        if (!DIFF_FILE_VALID(one))
2224                return NULL;
2225
2226        diff_filespec_load_driver(one);
2227        return userdiff_get_textconv(one->driver);
2228}
2229
2230static void builtin_diff(const char *name_a,
2231                         const char *name_b,
2232                         struct diff_filespec *one,
2233                         struct diff_filespec *two,
2234                         const char *xfrm_msg,
2235                         int must_show_header,
2236                         struct diff_options *o,
2237                         int complete_rewrite)
2238{
2239        mmfile_t mf1, mf2;
2240        const char *lbl[2];
2241        char *a_one, *b_two;
2242        const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2243        const char *reset = diff_get_color_opt(o, DIFF_RESET);
2244        const char *a_prefix, *b_prefix;
2245        struct userdiff_driver *textconv_one = NULL;
2246        struct userdiff_driver *textconv_two = NULL;
2247        struct strbuf header = STRBUF_INIT;
2248        const char *line_prefix = diff_line_prefix(o);
2249
2250        if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2251                        (!one->mode || S_ISGITLINK(one->mode)) &&
2252                        (!two->mode || S_ISGITLINK(two->mode))) {
2253                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2254                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2255                show_submodule_summary(o->file, one->path ? one->path : two->path,
2256                                line_prefix,
2257                                one->sha1, two->sha1, two->dirty_submodule,
2258                                meta, del, add, reset);
2259                return;
2260        }
2261
2262        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2263                textconv_one = get_textconv(one);
2264                textconv_two = get_textconv(two);
2265        }
2266
2267        diff_set_mnemonic_prefix(o, "a/", "b/");
2268        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2269                a_prefix = o->b_prefix;
2270                b_prefix = o->a_prefix;
2271        } else {
2272                a_prefix = o->a_prefix;
2273                b_prefix = o->b_prefix;
2274        }
2275
2276        /* Never use a non-valid filename anywhere if at all possible */
2277        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2278        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2279
2280        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2281        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2282        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2283        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2284        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2285        if (lbl[0][0] == '/') {
2286                /* /dev/null */
2287                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2288                if (xfrm_msg)
2289                        strbuf_addstr(&header, xfrm_msg);
2290                must_show_header = 1;
2291        }
2292        else if (lbl[1][0] == '/') {
2293                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2294                if (xfrm_msg)
2295                        strbuf_addstr(&header, xfrm_msg);
2296                must_show_header = 1;
2297        }
2298        else {
2299                if (one->mode != two->mode) {
2300                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2301                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2302                        must_show_header = 1;
2303                }
2304                if (xfrm_msg)
2305                        strbuf_addstr(&header, xfrm_msg);
2306
2307                /*
2308                 * we do not run diff between different kind
2309                 * of objects.
2310                 */
2311                if ((one->mode ^ two->mode) & S_IFMT)
2312                        goto free_ab_and_return;
2313                if (complete_rewrite &&
2314                    (textconv_one || !diff_filespec_is_binary(one)) &&
2315                    (textconv_two || !diff_filespec_is_binary(two))) {
2316                        fprintf(o->file, "%s", header.buf);
2317                        strbuf_reset(&header);
2318                        emit_rewrite_diff(name_a, name_b, one, two,
2319                                                textconv_one, textconv_two, o);
2320                        o->found_changes = 1;
2321                        goto free_ab_and_return;
2322                }
2323        }
2324
2325        if (o->irreversible_delete && lbl[1][0] == '/') {
2326                fprintf(o->file, "%s", header.buf);
2327                strbuf_reset(&header);
2328                goto free_ab_and_return;
2329        } else if (!DIFF_OPT_TST(o, TEXT) &&
2330            ( (!textconv_one && diff_filespec_is_binary(one)) ||
2331              (!textconv_two && diff_filespec_is_binary(two)) )) {
2332                if (!one->data && !two->data &&
2333                    S_ISREG(one->mode) && S_ISREG(two->mode) &&
2334                    !DIFF_OPT_TST(o, BINARY)) {
2335                        if (!hashcmp(one->sha1, two->sha1)) {
2336                                if (must_show_header)
2337                                        fprintf(o->file, "%s", header.buf);
2338                                goto free_ab_and_return;
2339                        }
2340                        fprintf(o->file, "%s", header.buf);
2341                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2342                                line_prefix, lbl[0], lbl[1]);
2343                        goto free_ab_and_return;
2344                }
2345                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2346                        die("unable to read files to diff");
2347                /* Quite common confusing case */
2348                if (mf1.size == mf2.size &&
2349                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2350                        if (must_show_header)
2351                                fprintf(o->file, "%s", header.buf);
2352                        goto free_ab_and_return;
2353                }
2354                fprintf(o->file, "%s", header.buf);
2355                strbuf_reset(&header);
2356                if (DIFF_OPT_TST(o, BINARY))
2357                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2358                else
2359                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2360                                line_prefix, lbl[0], lbl[1]);
2361                o->found_changes = 1;
2362        } else {
2363                /* Crazy xdl interfaces.. */
2364                const char *diffopts = getenv("GIT_DIFF_OPTS");
2365                const char *v;
2366                xpparam_t xpp;
2367                xdemitconf_t xecfg;
2368                struct emit_callback ecbdata;
2369                const struct userdiff_funcname *pe;
2370
2371                if (must_show_header) {
2372                        fprintf(o->file, "%s", header.buf);
2373                        strbuf_reset(&header);
2374                }
2375
2376                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2377                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2378
2379                pe = diff_funcname_pattern(one);
2380                if (!pe)
2381                        pe = diff_funcname_pattern(two);
2382
2383                memset(&xpp, 0, sizeof(xpp));
2384                memset(&xecfg, 0, sizeof(xecfg));
2385                memset(&ecbdata, 0, sizeof(ecbdata));
2386                ecbdata.label_path = lbl;
2387                ecbdata.color_diff = want_color(o->use_color);
2388                ecbdata.found_changesp = &o->found_changes;
2389                ecbdata.ws_rule = whitespace_rule(name_b);
2390                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2391                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2392                ecbdata.opt = o;
2393                ecbdata.header = header.len ? &header : NULL;
2394                xpp.flags = o->xdl_opts;
2395                xecfg.ctxlen = o->context;
2396                xecfg.interhunkctxlen = o->interhunkcontext;
2397                xecfg.flags = XDL_EMIT_FUNCNAMES;
2398                if (DIFF_OPT_TST(o, FUNCCONTEXT))
2399                        xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2400                if (pe)
2401                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2402                if (!diffopts)
2403                        ;
2404                else if (skip_prefix(diffopts, "--unified=", &v))
2405                        xecfg.ctxlen = strtoul(v, NULL, 10);
2406                else if (skip_prefix(diffopts, "-u", &v))
2407                        xecfg.ctxlen = strtoul(v, NULL, 10);
2408                if (o->word_diff)
2409                        init_diff_words_data(&ecbdata, o, one, two);
2410                xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2411                              &xpp, &xecfg);
2412                if (o->word_diff)
2413                        free_diff_words_data(&ecbdata);
2414                if (textconv_one)
2415                        free(mf1.ptr);
2416                if (textconv_two)
2417                        free(mf2.ptr);
2418                xdiff_clear_find_func(&xecfg);
2419        }
2420
2421 free_ab_and_return:
2422        strbuf_release(&header);
2423        diff_free_filespec_data(one);
2424        diff_free_filespec_data(two);
2425        free(a_one);
2426        free(b_two);
2427        return;
2428}
2429
2430static void builtin_diffstat(const char *name_a, const char *name_b,
2431                             struct diff_filespec *one,
2432                             struct diff_filespec *two,
2433                             struct diffstat_t *diffstat,
2434                             struct diff_options *o,
2435                             struct diff_filepair *p)
2436{
2437        mmfile_t mf1, mf2;
2438        struct diffstat_file *data;
2439        int same_contents;
2440        int complete_rewrite = 0;
2441
2442        if (!DIFF_PAIR_UNMERGED(p)) {
2443                if (p->status == DIFF_STATUS_MODIFIED && p->score)
2444                        complete_rewrite = 1;
2445        }
2446
2447        data = diffstat_add(diffstat, name_a, name_b);
2448        data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2449
2450        if (!one || !two) {
2451                data->is_unmerged = 1;
2452                return;
2453        }
2454
2455        same_contents = !hashcmp(one->sha1, two->sha1);
2456
2457        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2458                data->is_binary = 1;
2459                if (same_contents) {
2460                        data->added = 0;
2461                        data->deleted = 0;
2462                } else {
2463                        data->added = diff_filespec_size(two);
2464                        data->deleted = diff_filespec_size(one);
2465                }
2466        }
2467
2468        else if (complete_rewrite) {
2469                diff_populate_filespec(one, 0);
2470                diff_populate_filespec(two, 0);
2471                data->deleted = count_lines(one->data, one->size);
2472                data->added = count_lines(two->data, two->size);
2473        }
2474
2475        else if (!same_contents) {
2476                /* Crazy xdl interfaces.. */
2477                xpparam_t xpp;
2478                xdemitconf_t xecfg;
2479
2480                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2481                        die("unable to read files to diff");
2482
2483                memset(&xpp, 0, sizeof(xpp));
2484                memset(&xecfg, 0, sizeof(xecfg));
2485                xpp.flags = o->xdl_opts;
2486                xecfg.ctxlen = o->context;
2487                xecfg.interhunkctxlen = o->interhunkcontext;
2488                xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2489                              &xpp, &xecfg);
2490        }
2491
2492        diff_free_filespec_data(one);
2493        diff_free_filespec_data(two);
2494}
2495
2496static void builtin_checkdiff(const char *name_a, const char *name_b,
2497                              const char *attr_path,
2498                              struct diff_filespec *one,
2499                              struct diff_filespec *two,
2500                              struct diff_options *o)
2501{
2502        mmfile_t mf1, mf2;
2503        struct checkdiff_t data;
2504
2505        if (!two)
2506                return;
2507
2508        memset(&data, 0, sizeof(data));
2509        data.filename = name_b ? name_b : name_a;
2510        data.lineno = 0;
2511        data.o = o;
2512        data.ws_rule = whitespace_rule(attr_path);
2513        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2514
2515        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2516                die("unable to read files to diff");
2517
2518        /*
2519         * All the other codepaths check both sides, but not checking
2520         * the "old" side here is deliberate.  We are checking the newly
2521         * introduced changes, and as long as the "new" side is text, we
2522         * can and should check what it introduces.
2523         */
2524        if (diff_filespec_is_binary(two))
2525                goto free_and_return;
2526        else {
2527                /* Crazy xdl interfaces.. */
2528                xpparam_t xpp;
2529                xdemitconf_t xecfg;
2530
2531                memset(&xpp, 0, sizeof(xpp));
2532                memset(&xecfg, 0, sizeof(xecfg));
2533                xecfg.ctxlen = 1; /* at least one context line */
2534                xpp.flags = 0;
2535                xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2536                              &xpp, &xecfg);
2537
2538                if (data.ws_rule & WS_BLANK_AT_EOF) {
2539                        struct emit_callback ecbdata;
2540                        int blank_at_eof;
2541
2542                        ecbdata.ws_rule = data.ws_rule;
2543                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2544                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2545
2546                        if (blank_at_eof) {
2547                                static char *err;
2548                                if (!err)
2549                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2550                                fprintf(o->file, "%s:%d: %s.\n",
2551                                        data.filename, blank_at_eof, err);
2552                                data.status = 1; /* report errors */
2553                        }
2554                }
2555        }
2556 free_and_return:
2557        diff_free_filespec_data(one);
2558        diff_free_filespec_data(two);
2559        if (data.status)
2560                DIFF_OPT_SET(o, CHECK_FAILED);
2561}
2562
2563struct diff_filespec *alloc_filespec(const char *path)
2564{
2565        int namelen = strlen(path);
2566        struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
2567
2568        memset(spec, 0, sizeof(*spec));
2569        spec->path = (char *)(spec + 1);
2570        memcpy(spec->path, path, namelen+1);
2571        spec->count = 1;
2572        spec->is_binary = -1;
2573        return spec;
2574}
2575
2576void free_filespec(struct diff_filespec *spec)
2577{
2578        if (!--spec->count) {
2579                diff_free_filespec_data(spec);
2580                free(spec);
2581        }
2582}
2583
2584void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2585                   int sha1_valid, unsigned short mode)
2586{
2587        if (mode) {
2588                spec->mode = canon_mode(mode);
2589                hashcpy(spec->sha1, sha1);
2590                spec->sha1_valid = sha1_valid;
2591        }
2592}
2593
2594/*
2595 * Given a name and sha1 pair, if the index tells us the file in
2596 * the work tree has that object contents, return true, so that
2597 * prepare_temp_file() does not have to inflate and extract.
2598 */
2599static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2600{
2601        const struct cache_entry *ce;
2602        struct stat st;
2603        int pos, len;
2604
2605        /*
2606         * We do not read the cache ourselves here, because the
2607         * benchmark with my previous version that always reads cache
2608         * shows that it makes things worse for diff-tree comparing
2609         * two linux-2.6 kernel trees in an already checked out work
2610         * tree.  This is because most diff-tree comparisons deal with
2611         * only a small number of files, while reading the cache is
2612         * expensive for a large project, and its cost outweighs the
2613         * savings we get by not inflating the object to a temporary
2614         * file.  Practically, this code only helps when we are used
2615         * by diff-cache --cached, which does read the cache before
2616         * calling us.
2617         */
2618        if (!active_cache)
2619                return 0;
2620
2621        /* We want to avoid the working directory if our caller
2622         * doesn't need the data in a normal file, this system
2623         * is rather slow with its stat/open/mmap/close syscalls,
2624         * and the object is contained in a pack file.  The pack
2625         * is probably already open and will be faster to obtain
2626         * the data through than the working directory.  Loose
2627         * objects however would tend to be slower as they need
2628         * to be individually opened and inflated.
2629         */
2630        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2631                return 0;
2632
2633        len = strlen(name);
2634        pos = cache_name_pos(name, len);
2635        if (pos < 0)
2636                return 0;
2637        ce = active_cache[pos];
2638
2639        /*
2640         * This is not the sha1 we are looking for, or
2641         * unreusable because it is not a regular file.
2642         */
2643        if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2644                return 0;
2645
2646        /*
2647         * If ce is marked as "assume unchanged", there is no
2648         * guarantee that work tree matches what we are looking for.
2649         */
2650        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2651                return 0;
2652
2653        /*
2654         * If ce matches the file in the work tree, we can reuse it.
2655         */
2656        if (ce_uptodate(ce) ||
2657            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2658                return 1;
2659
2660        return 0;
2661}
2662
2663static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2664{
2665        int len;
2666        char *data = xmalloc(100), *dirty = "";
2667
2668        /* Are we looking at the work tree? */
2669        if (s->dirty_submodule)
2670                dirty = "-dirty";
2671
2672        len = snprintf(data, 100,
2673                       "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2674        s->data = data;
2675        s->size = len;
2676        s->should_free = 1;
2677        if (size_only) {
2678                s->data = NULL;
2679                free(data);
2680        }
2681        return 0;
2682}
2683
2684/*
2685 * While doing rename detection and pickaxe operation, we may need to
2686 * grab the data for the blob (or file) for our own in-core comparison.
2687 * diff_filespec has data and size fields for this purpose.
2688 */
2689int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
2690{
2691        int size_only = flags & CHECK_SIZE_ONLY;
2692        int err = 0;
2693        /*
2694         * demote FAIL to WARN to allow inspecting the situation
2695         * instead of refusing.
2696         */
2697        enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
2698                                    ? SAFE_CRLF_WARN
2699                                    : safe_crlf);
2700
2701        if (!DIFF_FILE_VALID(s))
2702                die("internal error: asking to populate invalid file.");
2703        if (S_ISDIR(s->mode))
2704                return -1;
2705
2706        if (s->data)
2707                return 0;
2708
2709        if (size_only && 0 < s->size)
2710                return 0;
2711
2712        if (S_ISGITLINK(s->mode))
2713                return diff_populate_gitlink(s, size_only);
2714
2715        if (!s->sha1_valid ||
2716            reuse_worktree_file(s->path, s->sha1, 0)) {
2717                struct strbuf buf = STRBUF_INIT;
2718                struct stat st;
2719                int fd;
2720
2721                if (lstat(s->path, &st) < 0) {
2722                        if (errno == ENOENT) {
2723                        err_empty:
2724                                err = -1;
2725                        empty:
2726                                s->data = (char *)"";
2727                                s->size = 0;
2728                                return err;
2729                        }
2730                }
2731                s->size = xsize_t(st.st_size);
2732                if (!s->size)
2733                        goto empty;
2734                if (S_ISLNK(st.st_mode)) {
2735                        struct strbuf sb = STRBUF_INIT;
2736
2737                        if (strbuf_readlink(&sb, s->path, s->size))
2738                                goto err_empty;
2739                        s->size = sb.len;
2740                        s->data = strbuf_detach(&sb, NULL);
2741                        s->should_free = 1;
2742                        return 0;
2743                }
2744                if (size_only)
2745                        return 0;
2746                if ((flags & CHECK_BINARY) &&
2747                    s->size > big_file_threshold && s->is_binary == -1) {
2748                        s->is_binary = 1;
2749                        return 0;
2750                }
2751                fd = open(s->path, O_RDONLY);
2752                if (fd < 0)
2753                        goto err_empty;
2754                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2755                close(fd);
2756                s->should_munmap = 1;
2757
2758                /*
2759                 * Convert from working tree format to canonical git format
2760                 */
2761                if (convert_to_git(s->path, s->data, s->size, &buf, crlf_warn)) {
2762                        size_t size = 0;
2763                        munmap(s->data, s->size);
2764                        s->should_munmap = 0;
2765                        s->data = strbuf_detach(&buf, &size);
2766                        s->size = size;
2767                        s->should_free = 1;
2768                }
2769        }
2770        else {
2771                enum object_type type;
2772                if (size_only || (flags & CHECK_BINARY)) {
2773                        type = sha1_object_info(s->sha1, &s->size);
2774                        if (type < 0)
2775                                die("unable to read %s", sha1_to_hex(s->sha1));
2776                        if (size_only)
2777                                return 0;
2778                        if (s->size > big_file_threshold && s->is_binary == -1) {
2779                                s->is_binary = 1;
2780                                return 0;
2781                        }
2782                }
2783                s->data = read_sha1_file(s->sha1, &type, &s->size);
2784                if (!s->data)
2785                        die("unable to read %s", sha1_to_hex(s->sha1));
2786                s->should_free = 1;
2787        }
2788        return 0;
2789}
2790
2791void diff_free_filespec_blob(struct diff_filespec *s)
2792{
2793        if (s->should_free)
2794                free(s->data);
2795        else if (s->should_munmap)
2796                munmap(s->data, s->size);
2797
2798        if (s->should_free || s->should_munmap) {
2799                s->should_free = s->should_munmap = 0;
2800                s->data = NULL;
2801        }
2802}
2803
2804void diff_free_filespec_data(struct diff_filespec *s)
2805{
2806        diff_free_filespec_blob(s);
2807        free(s->cnt_data);
2808        s->cnt_data = NULL;
2809}
2810
2811static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2812                           void *blob,
2813                           unsigned long size,
2814                           const unsigned char *sha1,
2815                           int mode)
2816{
2817        int fd;
2818        struct strbuf buf = STRBUF_INIT;
2819        struct strbuf template = STRBUF_INIT;
2820        char *path_dup = xstrdup(path);
2821        const char *base = basename(path_dup);
2822
2823        /* Generate "XXXXXX_basename.ext" */
2824        strbuf_addstr(&template, "XXXXXX_");
2825        strbuf_addstr(&template, base);
2826
2827        fd = mks_tempfile_ts(&temp->tempfile, template.buf, strlen(base) + 1);
2828        if (fd < 0)
2829                die_errno("unable to create temp-file");
2830        if (convert_to_working_tree(path,
2831                        (const char *)blob, (size_t)size, &buf)) {
2832                blob = buf.buf;
2833                size = buf.len;
2834        }
2835        if (write_in_full(fd, blob, size) != size)
2836                die_errno("unable to write temp-file");
2837        close_tempfile(&temp->tempfile);
2838        temp->name = get_tempfile_path(&temp->tempfile);
2839        strcpy(temp->hex, sha1_to_hex(sha1));
2840        temp->hex[40] = 0;
2841        sprintf(temp->mode, "%06o", mode);
2842        strbuf_release(&buf);
2843        strbuf_release(&template);
2844        free(path_dup);
2845}
2846
2847static struct diff_tempfile *prepare_temp_file(const char *name,
2848                struct diff_filespec *one)
2849{
2850        struct diff_tempfile *temp = claim_diff_tempfile();
2851
2852        if (!DIFF_FILE_VALID(one)) {
2853        not_a_valid_file:
2854                /* A '-' entry produces this for file-2, and
2855                 * a '+' entry produces this for file-1.
2856                 */
2857                temp->name = "/dev/null";
2858                strcpy(temp->hex, ".");
2859                strcpy(temp->mode, ".");
2860                return temp;
2861        }
2862
2863        if (!S_ISGITLINK(one->mode) &&
2864            (!one->sha1_valid ||
2865             reuse_worktree_file(name, one->sha1, 1))) {
2866                struct stat st;
2867                if (lstat(name, &st) < 0) {
2868                        if (errno == ENOENT)
2869                                goto not_a_valid_file;
2870                        die_errno("stat(%s)", name);
2871                }
2872                if (S_ISLNK(st.st_mode)) {
2873                        struct strbuf sb = STRBUF_INIT;
2874                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
2875                                die_errno("readlink(%s)", name);
2876                        prep_temp_blob(name, temp, sb.buf, sb.len,
2877                                       (one->sha1_valid ?
2878                                        one->sha1 : null_sha1),
2879                                       (one->sha1_valid ?
2880                                        one->mode : S_IFLNK));
2881                        strbuf_release(&sb);
2882                }
2883                else {
2884                        /* we can borrow from the file in the work tree */
2885                        temp->name = name;
2886                        if (!one->sha1_valid)
2887                                strcpy(temp->hex, sha1_to_hex(null_sha1));
2888                        else
2889                                strcpy(temp->hex, sha1_to_hex(one->sha1));
2890                        /* Even though we may sometimes borrow the
2891                         * contents from the work tree, we always want
2892                         * one->mode.  mode is trustworthy even when
2893                         * !(one->sha1_valid), as long as
2894                         * DIFF_FILE_VALID(one).
2895                         */
2896                        sprintf(temp->mode, "%06o", one->mode);
2897                }
2898                return temp;
2899        }
2900        else {
2901                if (diff_populate_filespec(one, 0))
2902                        die("cannot read data blob for %s", one->path);
2903                prep_temp_blob(name, temp, one->data, one->size,
2904                               one->sha1, one->mode);
2905        }
2906        return temp;
2907}
2908
2909static void add_external_diff_name(struct argv_array *argv,
2910                                   const char *name,
2911                                   struct diff_filespec *df)
2912{
2913        struct diff_tempfile *temp = prepare_temp_file(name, df);
2914        argv_array_push(argv, temp->name);
2915        argv_array_push(argv, temp->hex);
2916        argv_array_push(argv, temp->mode);
2917}
2918
2919/* An external diff command takes:
2920 *
2921 * diff-cmd name infile1 infile1-sha1 infile1-mode \
2922 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2923 *
2924 */
2925static void run_external_diff(const char *pgm,
2926                              const char *name,
2927                              const char *other,
2928                              struct diff_filespec *one,
2929                              struct diff_filespec *two,
2930                              const char *xfrm_msg,
2931                              int complete_rewrite,
2932                              struct diff_options *o)
2933{
2934        struct argv_array argv = ARGV_ARRAY_INIT;
2935        struct argv_array env = ARGV_ARRAY_INIT;
2936        struct diff_queue_struct *q = &diff_queued_diff;
2937
2938        argv_array_push(&argv, pgm);
2939        argv_array_push(&argv, name);
2940
2941        if (one && two) {
2942                add_external_diff_name(&argv, name, one);
2943                if (!other)
2944                        add_external_diff_name(&argv, name, two);
2945                else {
2946                        add_external_diff_name(&argv, other, two);
2947                        argv_array_push(&argv, other);
2948                        argv_array_push(&argv, xfrm_msg);
2949                }
2950        }
2951
2952        argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
2953        argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
2954
2955        if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
2956                die(_("external diff died, stopping at %s"), name);
2957
2958        remove_tempfile();
2959        argv_array_clear(&argv);
2960        argv_array_clear(&env);
2961}
2962
2963static int similarity_index(struct diff_filepair *p)
2964{
2965        return p->score * 100 / MAX_SCORE;
2966}
2967
2968static void fill_metainfo(struct strbuf *msg,
2969                          const char *name,
2970                          const char *other,
2971                          struct diff_filespec *one,
2972                          struct diff_filespec *two,
2973                          struct diff_options *o,
2974                          struct diff_filepair *p,
2975                          int *must_show_header,
2976                          int use_color)
2977{
2978        const char *set = diff_get_color(use_color, DIFF_METAINFO);
2979        const char *reset = diff_get_color(use_color, DIFF_RESET);
2980        const char *line_prefix = diff_line_prefix(o);
2981
2982        *must_show_header = 1;
2983        strbuf_init(msg, PATH_MAX * 2 + 300);
2984        switch (p->status) {
2985        case DIFF_STATUS_COPIED:
2986                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2987                            line_prefix, set, similarity_index(p));
2988                strbuf_addf(msg, "%s\n%s%scopy from ",
2989                            reset,  line_prefix, set);
2990                quote_c_style(name, msg, NULL, 0);
2991                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
2992                quote_c_style(other, msg, NULL, 0);
2993                strbuf_addf(msg, "%s\n", reset);
2994                break;
2995        case DIFF_STATUS_RENAMED:
2996                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2997                            line_prefix, set, similarity_index(p));
2998                strbuf_addf(msg, "%s\n%s%srename from ",
2999                            reset, line_prefix, set);
3000                quote_c_style(name, msg, NULL, 0);
3001                strbuf_addf(msg, "%s\n%s%srename to ",
3002                            reset, line_prefix, set);
3003                quote_c_style(other, msg, NULL, 0);
3004                strbuf_addf(msg, "%s\n", reset);
3005                break;
3006        case DIFF_STATUS_MODIFIED:
3007                if (p->score) {
3008                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3009                                    line_prefix,
3010                                    set, similarity_index(p), reset);
3011                        break;
3012                }
3013                /* fallthru */
3014        default:
3015                *must_show_header = 0;
3016        }
3017        if (one && two && hashcmp(one->sha1, two->sha1)) {
3018                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3019
3020                if (DIFF_OPT_TST(o, BINARY)) {
3021                        mmfile_t mf;
3022                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3023                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3024                                abbrev = 40;
3025                }
3026                strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
3027                            find_unique_abbrev(one->sha1, abbrev));
3028                strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
3029                if (one->mode == two->mode)
3030                        strbuf_addf(msg, " %06o", one->mode);
3031                strbuf_addf(msg, "%s\n", reset);
3032        }
3033}
3034
3035static void run_diff_cmd(const char *pgm,
3036                         const char *name,
3037                         const char *other,
3038                         const char *attr_path,
3039                         struct diff_filespec *one,
3040                         struct diff_filespec *two,
3041                         struct strbuf *msg,
3042                         struct diff_options *o,
3043                         struct diff_filepair *p)
3044{
3045        const char *xfrm_msg = NULL;
3046        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3047        int must_show_header = 0;
3048
3049
3050        if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3051                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3052                if (drv && drv->external)
3053                        pgm = drv->external;
3054        }
3055
3056        if (msg) {
3057                /*
3058                 * don't use colors when the header is intended for an
3059                 * external diff driver
3060                 */
3061                fill_metainfo(msg, name, other, one, two, o, p,
3062                              &must_show_header,
3063                              want_color(o->use_color) && !pgm);
3064                xfrm_msg = msg->len ? msg->buf : NULL;
3065        }
3066
3067        if (pgm) {
3068                run_external_diff(pgm, name, other, one, two, xfrm_msg,
3069                                  complete_rewrite, o);
3070                return;
3071        }
3072        if (one && two)
3073                builtin_diff(name, other ? other : name,
3074                             one, two, xfrm_msg, must_show_header,
3075                             o, complete_rewrite);
3076        else
3077                fprintf(o->file, "* Unmerged path %s\n", name);
3078}
3079
3080static void diff_fill_sha1_info(struct diff_filespec *one)
3081{
3082        if (DIFF_FILE_VALID(one)) {
3083                if (!one->sha1_valid) {
3084                        struct stat st;
3085                        if (one->is_stdin) {
3086                                hashcpy(one->sha1, null_sha1);
3087                                return;
3088                        }
3089                        if (lstat(one->path, &st) < 0)
3090                                die_errno("stat '%s'", one->path);
3091                        if (index_path(one->sha1, one->path, &st, 0))
3092                                die("cannot hash %s", one->path);
3093                }
3094        }
3095        else
3096                hashclr(one->sha1);
3097}
3098
3099static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3100{
3101        /* Strip the prefix but do not molest /dev/null and absolute paths */
3102        if (*namep && **namep != '/') {
3103                *namep += prefix_length;
3104                if (**namep == '/')
3105                        ++*namep;
3106        }
3107        if (*otherp && **otherp != '/') {
3108                *otherp += prefix_length;
3109                if (**otherp == '/')
3110                        ++*otherp;
3111        }
3112}
3113
3114static void run_diff(struct diff_filepair *p, struct diff_options *o)
3115{
3116        const char *pgm = external_diff();
3117        struct strbuf msg;
3118        struct diff_filespec *one = p->one;
3119        struct diff_filespec *two = p->two;
3120        const char *name;
3121        const char *other;
3122        const char *attr_path;
3123
3124        name  = p->one->path;
3125        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3126        attr_path = name;
3127        if (o->prefix_length)
3128                strip_prefix(o->prefix_length, &name, &other);
3129
3130        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3131                pgm = NULL;
3132
3133        if (DIFF_PAIR_UNMERGED(p)) {
3134                run_diff_cmd(pgm, name, NULL, attr_path,
3135                             NULL, NULL, NULL, o, p);
3136                return;
3137        }
3138
3139        diff_fill_sha1_info(one);
3140        diff_fill_sha1_info(two);
3141
3142        if (!pgm &&
3143            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3144            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3145                /*
3146                 * a filepair that changes between file and symlink
3147                 * needs to be split into deletion and creation.
3148                 */
3149                struct diff_filespec *null = alloc_filespec(two->path);
3150                run_diff_cmd(NULL, name, other, attr_path,
3151                             one, null, &msg, o, p);
3152                free(null);
3153                strbuf_release(&msg);
3154
3155                null = alloc_filespec(one->path);
3156                run_diff_cmd(NULL, name, other, attr_path,
3157                             null, two, &msg, o, p);
3158                free(null);
3159        }
3160        else
3161                run_diff_cmd(pgm, name, other, attr_path,
3162                             one, two, &msg, o, p);
3163
3164        strbuf_release(&msg);
3165}
3166
3167static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3168                         struct diffstat_t *diffstat)
3169{
3170        const char *name;
3171        const char *other;
3172
3173        if (DIFF_PAIR_UNMERGED(p)) {
3174                /* unmerged */
3175                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3176                return;
3177        }
3178
3179        name = p->one->path;
3180        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3181
3182        if (o->prefix_length)
3183                strip_prefix(o->prefix_length, &name, &other);
3184
3185        diff_fill_sha1_info(p->one);
3186        diff_fill_sha1_info(p->two);
3187
3188        builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3189}
3190
3191static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3192{
3193        const char *name;
3194        const char *other;
3195        const char *attr_path;
3196
3197        if (DIFF_PAIR_UNMERGED(p)) {
3198                /* unmerged */
3199                return;
3200        }
3201
3202        name = p->one->path;
3203        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3204        attr_path = other ? other : name;
3205
3206        if (o->prefix_length)
3207                strip_prefix(o->prefix_length, &name, &other);
3208
3209        diff_fill_sha1_info(p->one);
3210        diff_fill_sha1_info(p->two);
3211
3212        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3213}
3214
3215void diff_setup(struct diff_options *options)
3216{
3217        memcpy(options, &default_diff_options, sizeof(*options));
3218
3219        options->file = stdout;
3220
3221        options->line_termination = '\n';
3222        options->break_opt = -1;
3223        options->rename_limit = -1;
3224        options->dirstat_permille = diff_dirstat_permille_default;
3225        options->context = diff_context_default;
3226        DIFF_OPT_SET(options, RENAME_EMPTY);
3227
3228        /* pathchange left =NULL by default */
3229        options->change = diff_change;
3230        options->add_remove = diff_addremove;
3231        options->use_color = diff_use_color_default;
3232        options->detect_rename = diff_detect_rename_default;
3233        options->xdl_opts |= diff_algorithm;
3234
3235        options->orderfile = diff_order_file_cfg;
3236
3237        if (diff_no_prefix) {
3238                options->a_prefix = options->b_prefix = "";
3239        } else if (!diff_mnemonic_prefix) {
3240                options->a_prefix = "a/";
3241                options->b_prefix = "b/";
3242        }
3243}
3244
3245void diff_setup_done(struct diff_options *options)
3246{
3247        int count = 0;
3248
3249        if (options->set_default)
3250                options->set_default(options);
3251
3252        if (options->output_format & DIFF_FORMAT_NAME)
3253                count++;
3254        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3255                count++;
3256        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3257                count++;
3258        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3259                count++;
3260        if (count > 1)
3261                die("--name-only, --name-status, --check and -s are mutually exclusive");
3262
3263        /*
3264         * Most of the time we can say "there are changes"
3265         * only by checking if there are changed paths, but
3266         * --ignore-whitespace* options force us to look
3267         * inside contents.
3268         */
3269
3270        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3271            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3272            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3273                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3274        else
3275                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3276
3277        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3278                options->detect_rename = DIFF_DETECT_COPY;
3279
3280        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3281                options->prefix = NULL;
3282        if (options->prefix)
3283                options->prefix_length = strlen(options->prefix);
3284        else
3285                options->prefix_length = 0;
3286
3287        if (options->output_format & (DIFF_FORMAT_NAME |
3288                                      DIFF_FORMAT_NAME_STATUS |
3289                                      DIFF_FORMAT_CHECKDIFF |
3290                                      DIFF_FORMAT_NO_OUTPUT))
3291                options->output_format &= ~(DIFF_FORMAT_RAW |
3292                                            DIFF_FORMAT_NUMSTAT |
3293                                            DIFF_FORMAT_DIFFSTAT |
3294                                            DIFF_FORMAT_SHORTSTAT |
3295                                            DIFF_FORMAT_DIRSTAT |
3296                                            DIFF_FORMAT_SUMMARY |
3297                                            DIFF_FORMAT_PATCH);
3298
3299        /*
3300         * These cases always need recursive; we do not drop caller-supplied
3301         * recursive bits for other formats here.
3302         */
3303        if (options->output_format & (DIFF_FORMAT_PATCH |
3304                                      DIFF_FORMAT_NUMSTAT |
3305                                      DIFF_FORMAT_DIFFSTAT |
3306                                      DIFF_FORMAT_SHORTSTAT |
3307                                      DIFF_FORMAT_DIRSTAT |
3308                                      DIFF_FORMAT_SUMMARY |
3309                                      DIFF_FORMAT_CHECKDIFF))
3310                DIFF_OPT_SET(options, RECURSIVE);
3311        /*
3312         * Also pickaxe would not work very well if you do not say recursive
3313         */
3314        if (options->pickaxe)
3315                DIFF_OPT_SET(options, RECURSIVE);
3316        /*
3317         * When patches are generated, submodules diffed against the work tree
3318         * must be checked for dirtiness too so it can be shown in the output
3319         */
3320        if (options->output_format & DIFF_FORMAT_PATCH)
3321                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3322
3323        if (options->detect_rename && options->rename_limit < 0)
3324                options->rename_limit = diff_rename_limit_default;
3325        if (options->setup & DIFF_SETUP_USE_CACHE) {
3326                if (!active_cache)
3327                        /* read-cache does not die even when it fails
3328                         * so it is safe for us to do this here.  Also
3329                         * it does not smudge active_cache or active_nr
3330                         * when it fails, so we do not have to worry about
3331                         * cleaning it up ourselves either.
3332                         */
3333                        read_cache();
3334        }
3335        if (options->abbrev <= 0 || 40 < options->abbrev)
3336                options->abbrev = 40; /* full */
3337
3338        /*
3339         * It does not make sense to show the first hit we happened
3340         * to have found.  It does not make sense not to return with
3341         * exit code in such a case either.
3342         */
3343        if (DIFF_OPT_TST(options, QUICK)) {
3344                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3345                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3346        }
3347
3348        options->diff_path_counter = 0;
3349
3350        if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
3351                die(_("--follow requires exactly one pathspec"));
3352}
3353
3354static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3355{
3356        char c, *eq;
3357        int len;
3358
3359        if (*arg != '-')
3360                return 0;
3361        c = *++arg;
3362        if (!c)
3363                return 0;
3364        if (c == arg_short) {
3365                c = *++arg;
3366                if (!c)
3367                        return 1;
3368                if (val && isdigit(c)) {
3369                        char *end;
3370                        int n = strtoul(arg, &end, 10);
3371                        if (*end)
3372                                return 0;
3373                        *val = n;
3374                        return 1;
3375                }
3376                return 0;
3377        }
3378        if (c != '-')
3379                return 0;
3380        arg++;
3381        eq = strchrnul(arg, '=');
3382        len = eq - arg;
3383        if (!len || strncmp(arg, arg_long, len))
3384                return 0;
3385        if (*eq) {
3386                int n;
3387                char *end;
3388                if (!isdigit(*++eq))
3389                        return 0;
3390                n = strtoul(eq, &end, 10);
3391                if (*end)
3392                        return 0;
3393                *val = n;
3394        }
3395        return 1;
3396}
3397
3398static int diff_scoreopt_parse(const char *opt);
3399
3400static inline int short_opt(char opt, const char **argv,
3401                            const char **optarg)
3402{
3403        const char *arg = argv[0];
3404        if (arg[0] != '-' || arg[1] != opt)
3405                return 0;
3406        if (arg[2] != '\0') {
3407                *optarg = arg + 2;
3408                return 1;
3409        }
3410        if (!argv[1])
3411                die("Option '%c' requires a value", opt);
3412        *optarg = argv[1];
3413        return 2;
3414}
3415
3416int parse_long_opt(const char *opt, const char **argv,
3417                   const char **optarg)
3418{
3419        const char *arg = argv[0];
3420        if (!skip_prefix(arg, "--", &arg))
3421                return 0;
3422        if (!skip_prefix(arg, opt, &arg))
3423                return 0;
3424        if (*arg == '=') { /* stuck form: --option=value */
3425                *optarg = arg + 1;
3426                return 1;
3427        }
3428        if (*arg != '\0')
3429                return 0;
3430        /* separate form: --option value */
3431        if (!argv[1])
3432                die("Option '--%s' requires a value", opt);
3433        *optarg = argv[1];
3434        return 2;
3435}
3436
3437static int stat_opt(struct diff_options *options, const char **av)
3438{
3439        const char *arg = av[0];
3440        char *end;
3441        int width = options->stat_width;
3442        int name_width = options->stat_name_width;
3443        int graph_width = options->stat_graph_width;
3444        int count = options->stat_count;
3445        int argcount = 1;
3446
3447        if (!skip_prefix(arg, "--stat", &arg))
3448                die("BUG: stat option does not begin with --stat: %s", arg);
3449        end = (char *)arg;
3450
3451        switch (*arg) {
3452        case '-':
3453                if (skip_prefix(arg, "-width", &arg)) {
3454                        if (*arg == '=')
3455                                width = strtoul(arg + 1, &end, 10);
3456                        else if (!*arg && !av[1])
3457                                die("Option '--stat-width' requires a value");
3458                        else if (!*arg) {
3459                                width = strtoul(av[1], &end, 10);
3460                                argcount = 2;
3461                        }
3462                } else if (skip_prefix(arg, "-name-width", &arg)) {
3463                        if (*arg == '=')
3464                                name_width = strtoul(arg + 1, &end, 10);
3465                        else if (!*arg && !av[1])
3466                                die("Option '--stat-name-width' requires a value");
3467                        else if (!*arg) {
3468                                name_width = strtoul(av[1], &end, 10);
3469                                argcount = 2;
3470                        }
3471                } else if (skip_prefix(arg, "-graph-width", &arg)) {
3472                        if (*arg == '=')
3473                                graph_width = strtoul(arg + 1, &end, 10);
3474                        else if (!*arg && !av[1])
3475                                die("Option '--stat-graph-width' requires a value");
3476                        else if (!*arg) {
3477                                graph_width = strtoul(av[1], &end, 10);
3478                                argcount = 2;
3479                        }
3480                } else if (skip_prefix(arg, "-count", &arg)) {
3481                        if (*arg == '=')
3482                                count = strtoul(arg + 1, &end, 10);
3483                        else if (!*arg && !av[1])
3484                                die("Option '--stat-count' requires a value");
3485                        else if (!*arg) {
3486                                count = strtoul(av[1], &end, 10);
3487                                argcount = 2;
3488                        }
3489                }
3490                break;
3491        case '=':
3492                width = strtoul(arg+1, &end, 10);
3493                if (*end == ',')
3494                        name_width = strtoul(end+1, &end, 10);
3495                if (*end == ',')
3496                        count = strtoul(end+1, &end, 10);
3497        }
3498
3499        /* Important! This checks all the error cases! */
3500        if (*end)
3501                return 0;
3502        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3503        options->stat_name_width = name_width;
3504        options->stat_graph_width = graph_width;
3505        options->stat_width = width;
3506        options->stat_count = count;
3507        return argcount;
3508}
3509
3510static int parse_dirstat_opt(struct diff_options *options, const char *params)
3511{
3512        struct strbuf errmsg = STRBUF_INIT;
3513        if (parse_dirstat_params(options, params, &errmsg))
3514                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3515                    errmsg.buf);
3516        strbuf_release(&errmsg);
3517        /*
3518         * The caller knows a dirstat-related option is given from the command
3519         * line; allow it to say "return this_function();"
3520         */
3521        options->output_format |= DIFF_FORMAT_DIRSTAT;
3522        return 1;
3523}
3524
3525static int parse_submodule_opt(struct diff_options *options, const char *value)
3526{
3527        if (parse_submodule_params(options, value))
3528                die(_("Failed to parse --submodule option parameter: '%s'"),
3529                        value);
3530        return 1;
3531}
3532
3533static const char diff_status_letters[] = {
3534        DIFF_STATUS_ADDED,
3535        DIFF_STATUS_COPIED,
3536        DIFF_STATUS_DELETED,
3537        DIFF_STATUS_MODIFIED,
3538        DIFF_STATUS_RENAMED,
3539        DIFF_STATUS_TYPE_CHANGED,
3540        DIFF_STATUS_UNKNOWN,
3541        DIFF_STATUS_UNMERGED,
3542        DIFF_STATUS_FILTER_AON,
3543        DIFF_STATUS_FILTER_BROKEN,
3544        '\0',
3545};
3546
3547static unsigned int filter_bit['Z' + 1];
3548
3549static void prepare_filter_bits(void)
3550{
3551        int i;
3552
3553        if (!filter_bit[DIFF_STATUS_ADDED]) {
3554                for (i = 0; diff_status_letters[i]; i++)
3555                        filter_bit[(int) diff_status_letters[i]] = (1 << i);
3556        }
3557}
3558
3559static unsigned filter_bit_tst(char status, const struct diff_options *opt)
3560{
3561        return opt->filter & filter_bit[(int) status];
3562}
3563
3564static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
3565{
3566        int i, optch;
3567
3568        prepare_filter_bits();
3569
3570        /*
3571         * If there is a negation e.g. 'd' in the input, and we haven't
3572         * initialized the filter field with another --diff-filter, start
3573         * from full set of bits, except for AON.
3574         */
3575        if (!opt->filter) {
3576                for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3577                        if (optch < 'a' || 'z' < optch)
3578                                continue;
3579                        opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
3580                        opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
3581                        break;
3582                }
3583        }
3584
3585        for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3586                unsigned int bit;
3587                int negate;
3588
3589                if ('a' <= optch && optch <= 'z') {
3590                        negate = 1;
3591                        optch = toupper(optch);
3592                } else {
3593                        negate = 0;
3594                }
3595
3596                bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
3597                if (!bit)
3598                        return optarg[i];
3599                if (negate)
3600                        opt->filter &= ~bit;
3601                else
3602                        opt->filter |= bit;
3603        }
3604        return 0;
3605}
3606
3607static void enable_patch_output(int *fmt) {
3608        *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
3609        *fmt |= DIFF_FORMAT_PATCH;
3610}
3611
3612int diff_opt_parse(struct diff_options *options, const char **av, int ac)
3613{
3614        const char *arg = av[0];
3615        const char *optarg;
3616        int argcount;
3617
3618        /* Output format options */
3619        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
3620            || opt_arg(arg, 'U', "unified", &options->context))
3621                enable_patch_output(&options->output_format);
3622        else if (!strcmp(arg, "--raw"))
3623                options->output_format |= DIFF_FORMAT_RAW;
3624        else if (!strcmp(arg, "--patch-with-raw")) {
3625                enable_patch_output(&options->output_format);
3626                options->output_format |= DIFF_FORMAT_RAW;
3627        } else if (!strcmp(arg, "--numstat"))
3628                options->output_format |= DIFF_FORMAT_NUMSTAT;
3629        else if (!strcmp(arg, "--shortstat"))
3630                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3631        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3632                return parse_dirstat_opt(options, "");
3633        else if (skip_prefix(arg, "-X", &arg))
3634                return parse_dirstat_opt(options, arg);
3635        else if (skip_prefix(arg, "--dirstat=", &arg))
3636                return parse_dirstat_opt(options, arg);
3637        else if (!strcmp(arg, "--cumulative"))
3638                return parse_dirstat_opt(options, "cumulative");
3639        else if (!strcmp(arg, "--dirstat-by-file"))
3640                return parse_dirstat_opt(options, "files");
3641        else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
3642                parse_dirstat_opt(options, "files");
3643                return parse_dirstat_opt(options, arg);
3644        }
3645        else if (!strcmp(arg, "--check"))
3646                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3647        else if (!strcmp(arg, "--summary"))
3648                options->output_format |= DIFF_FORMAT_SUMMARY;
3649        else if (!strcmp(arg, "--patch-with-stat")) {
3650                enable_patch_output(&options->output_format);
3651                options->output_format |= DIFF_FORMAT_DIFFSTAT;
3652        } else if (!strcmp(arg, "--name-only"))
3653                options->output_format |= DIFF_FORMAT_NAME;
3654        else if (!strcmp(arg, "--name-status"))
3655                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3656        else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
3657                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3658        else if (starts_with(arg, "--stat"))
3659                /* --stat, --stat-width, --stat-name-width, or --stat-count */
3660                return stat_opt(options, av);
3661
3662        /* renames options */
3663        else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
3664                 !strcmp(arg, "--break-rewrites")) {
3665                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3666                        return error("invalid argument to -B: %s", arg+2);
3667        }
3668        else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
3669                 !strcmp(arg, "--find-renames")) {
3670                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3671                        return error("invalid argument to -M: %s", arg+2);
3672                options->detect_rename = DIFF_DETECT_RENAME;
3673        }
3674        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3675                options->irreversible_delete = 1;
3676        }
3677        else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
3678                 !strcmp(arg, "--find-copies")) {
3679                if (options->detect_rename == DIFF_DETECT_COPY)
3680                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3681                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3682                        return error("invalid argument to -C: %s", arg+2);
3683                options->detect_rename = DIFF_DETECT_COPY;
3684        }
3685        else if (!strcmp(arg, "--no-renames"))
3686                options->detect_rename = 0;
3687        else if (!strcmp(arg, "--rename-empty"))
3688                DIFF_OPT_SET(options, RENAME_EMPTY);
3689        else if (!strcmp(arg, "--no-rename-empty"))
3690                DIFF_OPT_CLR(options, RENAME_EMPTY);
3691        else if (!strcmp(arg, "--relative"))
3692                DIFF_OPT_SET(options, RELATIVE_NAME);
3693        else if (skip_prefix(arg, "--relative=", &arg)) {
3694                DIFF_OPT_SET(options, RELATIVE_NAME);
3695                options->prefix = arg;
3696        }
3697
3698        /* xdiff options */
3699        else if (!strcmp(arg, "--minimal"))
3700                DIFF_XDL_SET(options, NEED_MINIMAL);
3701        else if (!strcmp(arg, "--no-minimal"))
3702                DIFF_XDL_CLR(options, NEED_MINIMAL);
3703        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3704                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3705        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3706                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3707        else if (!strcmp(arg, "--ignore-space-at-eol"))
3708                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3709        else if (!strcmp(arg, "--ignore-blank-lines"))
3710                DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
3711        else if (!strcmp(arg, "--patience"))
3712                options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3713        else if (!strcmp(arg, "--histogram"))
3714                options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3715        else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
3716                long value = parse_algorithm_value(optarg);
3717                if (value < 0)
3718                        return error("option diff-algorithm accepts \"myers\", "
3719                                     "\"minimal\", \"patience\" and \"histogram\"");
3720                /* clear out previous settings */
3721                DIFF_XDL_CLR(options, NEED_MINIMAL);
3722                options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3723                options->xdl_opts |= value;
3724                return argcount;
3725        }
3726
3727        /* flags options */
3728        else if (!strcmp(arg, "--binary")) {
3729                enable_patch_output(&options->output_format);
3730                DIFF_OPT_SET(options, BINARY);
3731        }
3732        else if (!strcmp(arg, "--full-index"))
3733                DIFF_OPT_SET(options, FULL_INDEX);
3734        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3735                DIFF_OPT_SET(options, TEXT);
3736        else if (!strcmp(arg, "-R"))
3737                DIFF_OPT_SET(options, REVERSE_DIFF);
3738        else if (!strcmp(arg, "--find-copies-harder"))
3739                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3740        else if (!strcmp(arg, "--follow"))
3741                DIFF_OPT_SET(options, FOLLOW_RENAMES);
3742        else if (!strcmp(arg, "--no-follow"))
3743                DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3744        else if (!strcmp(arg, "--color"))
3745                options->use_color = 1;
3746        else if (skip_prefix(arg, "--color=", &arg)) {
3747                int value = git_config_colorbool(NULL, arg);
3748                if (value < 0)
3749                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
3750                options->use_color = value;
3751        }
3752        else if (!strcmp(arg, "--no-color"))
3753                options->use_color = 0;
3754        else if (!strcmp(arg, "--color-words")) {
3755                options->use_color = 1;
3756                options->word_diff = DIFF_WORDS_COLOR;
3757        }
3758        else if (skip_prefix(arg, "--color-words=", &arg)) {
3759                options->use_color = 1;
3760                options->word_diff = DIFF_WORDS_COLOR;
3761                options->word_regex = arg;
3762        }
3763        else if (!strcmp(arg, "--word-diff")) {
3764                if (options->word_diff == DIFF_WORDS_NONE)
3765                        options->word_diff = DIFF_WORDS_PLAIN;
3766        }
3767        else if (skip_prefix(arg, "--word-diff=", &arg)) {
3768                if (!strcmp(arg, "plain"))
3769                        options->word_diff = DIFF_WORDS_PLAIN;
3770                else if (!strcmp(arg, "color")) {
3771                        options->use_color = 1;
3772                        options->word_diff = DIFF_WORDS_COLOR;
3773                }
3774                else if (!strcmp(arg, "porcelain"))
3775                        options->word_diff = DIFF_WORDS_PORCELAIN;
3776                else if (!strcmp(arg, "none"))
3777                        options->word_diff = DIFF_WORDS_NONE;
3778                else
3779                        die("bad --word-diff argument: %s", arg);
3780        }
3781        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3782                if (options->word_diff == DIFF_WORDS_NONE)
3783                        options->word_diff = DIFF_WORDS_PLAIN;
3784                options->word_regex = optarg;
3785                return argcount;
3786        }
3787        else if (!strcmp(arg, "--exit-code"))
3788                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3789        else if (!strcmp(arg, "--quiet"))
3790                DIFF_OPT_SET(options, QUICK);
3791        else if (!strcmp(arg, "--ext-diff"))
3792                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3793        else if (!strcmp(arg, "--no-ext-diff"))
3794                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3795        else if (!strcmp(arg, "--textconv"))
3796                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3797        else if (!strcmp(arg, "--no-textconv"))
3798                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3799        else if (!strcmp(arg, "--ignore-submodules")) {
3800                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3801                handle_ignore_submodules_arg(options, "all");
3802        } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
3803                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3804                handle_ignore_submodules_arg(options, arg);
3805        } else if (!strcmp(arg, "--submodule"))
3806                DIFF_OPT_SET(options, SUBMODULE_LOG);
3807        else if (skip_prefix(arg, "--submodule=", &arg))
3808                return parse_submodule_opt(options, arg);
3809
3810        /* misc options */
3811        else if (!strcmp(arg, "-z"))
3812                options->line_termination = 0;
3813        else if ((argcount = short_opt('l', av, &optarg))) {
3814                options->rename_limit = strtoul(optarg, NULL, 10);
3815                return argcount;
3816        }
3817        else if ((argcount = short_opt('S', av, &optarg))) {
3818                options->pickaxe = optarg;
3819                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3820                return argcount;
3821        } else if ((argcount = short_opt('G', av, &optarg))) {
3822                options->pickaxe = optarg;
3823                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3824                return argcount;
3825        }
3826        else if (!strcmp(arg, "--pickaxe-all"))
3827                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3828        else if (!strcmp(arg, "--pickaxe-regex"))
3829                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3830        else if ((argcount = short_opt('O', av, &optarg))) {
3831                options->orderfile = optarg;
3832                return argcount;
3833        }
3834        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3835                int offending = parse_diff_filter_opt(optarg, options);
3836                if (offending)
3837                        die("unknown change class '%c' in --diff-filter=%s",
3838                            offending, optarg);
3839                return argcount;
3840        }
3841        else if (!strcmp(arg, "--abbrev"))
3842                options->abbrev = DEFAULT_ABBREV;
3843        else if (skip_prefix(arg, "--abbrev=", &arg)) {
3844                options->abbrev = strtoul(arg, NULL, 10);
3845                if (options->abbrev < MINIMUM_ABBREV)
3846                        options->abbrev = MINIMUM_ABBREV;
3847                else if (40 < options->abbrev)
3848                        options->abbrev = 40;
3849        }
3850        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3851                options->a_prefix = optarg;
3852                return argcount;
3853        }
3854        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3855                options->b_prefix = optarg;
3856                return argcount;
3857        }
3858        else if (!strcmp(arg, "--no-prefix"))
3859                options->a_prefix = options->b_prefix = "";
3860        else if (opt_arg(arg, '\0', "inter-hunk-context",
3861                         &options->interhunkcontext))
3862                ;
3863        else if (!strcmp(arg, "-W"))
3864                DIFF_OPT_SET(options, FUNCCONTEXT);
3865        else if (!strcmp(arg, "--function-context"))
3866                DIFF_OPT_SET(options, FUNCCONTEXT);
3867        else if (!strcmp(arg, "--no-function-context"))
3868                DIFF_OPT_CLR(options, FUNCCONTEXT);
3869        else if ((argcount = parse_long_opt("output", av, &optarg))) {
3870                options->file = fopen(optarg, "w");
3871                if (!options->file)
3872                        die_errno("Could not open '%s'", optarg);
3873                options->close_file = 1;
3874                return argcount;
3875        } else
3876                return 0;
3877        return 1;
3878}
3879
3880int parse_rename_score(const char **cp_p)
3881{
3882        unsigned long num, scale;
3883        int ch, dot;
3884        const char *cp = *cp_p;
3885
3886        num = 0;
3887        scale = 1;
3888        dot = 0;
3889        for (;;) {
3890                ch = *cp;
3891                if ( !dot && ch == '.' ) {
3892                        scale = 1;
3893                        dot = 1;
3894                } else if ( ch == '%' ) {
3895                        scale = dot ? scale*100 : 100;
3896                        cp++;   /* % is always at the end */
3897                        break;
3898                } else if ( ch >= '0' && ch <= '9' ) {
3899                        if ( scale < 100000 ) {
3900                                scale *= 10;
3901                                num = (num*10) + (ch-'0');
3902                        }
3903                } else {
3904                        break;
3905                }
3906                cp++;
3907        }
3908        *cp_p = cp;
3909
3910        /* user says num divided by scale and we say internally that
3911         * is MAX_SCORE * num / scale.
3912         */
3913        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
3914}
3915
3916static int diff_scoreopt_parse(const char *opt)
3917{
3918        int opt1, opt2, cmd;
3919
3920        if (*opt++ != '-')
3921                return -1;
3922        cmd = *opt++;
3923        if (cmd == '-') {
3924                /* convert the long-form arguments into short-form versions */
3925                if (skip_prefix(opt, "break-rewrites", &opt)) {
3926                        if (*opt == 0 || *opt++ == '=')
3927                                cmd = 'B';
3928                } else if (skip_prefix(opt, "find-copies", &opt)) {
3929                        if (*opt == 0 || *opt++ == '=')
3930                                cmd = 'C';
3931                } else if (skip_prefix(opt, "find-renames", &opt)) {
3932                        if (*opt == 0 || *opt++ == '=')
3933                                cmd = 'M';
3934                }
3935        }
3936        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
3937                return -1; /* that is not a -M, -C, or -B option */
3938
3939        opt1 = parse_rename_score(&opt);
3940        if (cmd != 'B')
3941                opt2 = 0;
3942        else {
3943                if (*opt == 0)
3944                        opt2 = 0;
3945                else if (*opt != '/')
3946                        return -1; /* we expect -B80/99 or -B80 */
3947                else {
3948                        opt++;
3949                        opt2 = parse_rename_score(&opt);
3950                }
3951        }
3952        if (*opt != 0)
3953                return -1;
3954        return opt1 | (opt2 << 16);
3955}
3956
3957struct diff_queue_struct diff_queued_diff;
3958
3959void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
3960{
3961        ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
3962        queue->queue[queue->nr++] = dp;
3963}
3964
3965struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
3966                                 struct diff_filespec *one,
3967                                 struct diff_filespec *two)
3968{
3969        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
3970        dp->one = one;
3971        dp->two = two;
3972        if (queue)
3973                diff_q(queue, dp);
3974        return dp;
3975}
3976
3977void diff_free_filepair(struct diff_filepair *p)
3978{
3979        free_filespec(p->one);
3980        free_filespec(p->two);
3981        free(p);
3982}
3983
3984/* This is different from find_unique_abbrev() in that
3985 * it stuffs the result with dots for alignment.
3986 */
3987const char *diff_unique_abbrev(const unsigned char *sha1, int len)
3988{
3989        int abblen;
3990        const char *abbrev;
3991        if (len == 40)
3992                return sha1_to_hex(sha1);
3993
3994        abbrev = find_unique_abbrev(sha1, len);
3995        abblen = strlen(abbrev);
3996        if (abblen < 37) {
3997                static char hex[41];
3998                if (len < abblen && abblen <= len + 2)
3999                        sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
4000                else
4001                        sprintf(hex, "%s...", abbrev);
4002                return hex;
4003        }
4004        return sha1_to_hex(sha1);
4005}
4006
4007static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4008{
4009        int line_termination = opt->line_termination;
4010        int inter_name_termination = line_termination ? '\t' : '\0';
4011
4012        fprintf(opt->file, "%s", diff_line_prefix(opt));
4013        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4014                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4015                        diff_unique_abbrev(p->one->sha1, opt->abbrev));
4016                fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
4017        }
4018        if (p->score) {
4019                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4020                        inter_name_termination);
4021        } else {
4022                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4023        }
4024
4025        if (p->status == DIFF_STATUS_COPIED ||
4026            p->status == DIFF_STATUS_RENAMED) {
4027                const char *name_a, *name_b;
4028                name_a = p->one->path;
4029                name_b = p->two->path;
4030                strip_prefix(opt->prefix_length, &name_a, &name_b);
4031                write_name_quoted(name_a, opt->file, inter_name_termination);
4032                write_name_quoted(name_b, opt->file, line_termination);
4033        } else {
4034                const char *name_a, *name_b;
4035                name_a = p->one->mode ? p->one->path : p->two->path;
4036                name_b = NULL;
4037                strip_prefix(opt->prefix_length, &name_a, &name_b);
4038                write_name_quoted(name_a, opt->file, line_termination);
4039        }
4040}
4041
4042int diff_unmodified_pair(struct diff_filepair *p)
4043{
4044        /* This function is written stricter than necessary to support
4045         * the currently implemented transformers, but the idea is to
4046         * let transformers to produce diff_filepairs any way they want,
4047         * and filter and clean them up here before producing the output.
4048         */
4049        struct diff_filespec *one = p->one, *two = p->two;
4050
4051        if (DIFF_PAIR_UNMERGED(p))
4052                return 0; /* unmerged is interesting */
4053
4054        /* deletion, addition, mode or type change
4055         * and rename are all interesting.
4056         */
4057        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4058            DIFF_PAIR_MODE_CHANGED(p) ||
4059            strcmp(one->path, two->path))
4060                return 0;
4061
4062        /* both are valid and point at the same path.  that is, we are
4063         * dealing with a change.
4064         */
4065        if (one->sha1_valid && two->sha1_valid &&
4066            !hashcmp(one->sha1, two->sha1) &&
4067            !one->dirty_submodule && !two->dirty_submodule)
4068                return 1; /* no change */
4069        if (!one->sha1_valid && !two->sha1_valid)
4070                return 1; /* both look at the same file on the filesystem. */
4071        return 0;
4072}
4073
4074static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
4075{
4076        if (diff_unmodified_pair(p))
4077                return;
4078
4079        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4080            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4081                return; /* no tree diffs in patch format */
4082
4083        run_diff(p, o);
4084}
4085
4086static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
4087                            struct diffstat_t *diffstat)
4088{
4089        if (diff_unmodified_pair(p))
4090                return;
4091
4092        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4093            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4094                return; /* no useful stat for tree diffs */
4095
4096        run_diffstat(p, o, diffstat);
4097}
4098
4099static void diff_flush_checkdiff(struct diff_filepair *p,
4100                struct diff_options *o)
4101{
4102        if (diff_unmodified_pair(p))
4103                return;
4104
4105        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4106            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4107                return; /* nothing to check in tree diffs */
4108
4109        run_checkdiff(p, o);
4110}
4111
4112int diff_queue_is_empty(void)
4113{
4114        struct diff_queue_struct *q = &diff_queued_diff;
4115        int i;
4116        for (i = 0; i < q->nr; i++)
4117                if (!diff_unmodified_pair(q->queue[i]))
4118                        return 0;
4119        return 1;
4120}
4121
4122#if DIFF_DEBUG
4123void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4124{
4125        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4126                x, one ? one : "",
4127                s->path,
4128                DIFF_FILE_VALID(s) ? "valid" : "invalid",
4129                s->mode,
4130                s->sha1_valid ? sha1_to_hex(s->sha1) : "");
4131        fprintf(stderr, "queue[%d] %s size %lu\n",
4132                x, one ? one : "",
4133                s->size);
4134}
4135
4136void diff_debug_filepair(const struct diff_filepair *p, int i)
4137{
4138        diff_debug_filespec(p->one, i, "one");
4139        diff_debug_filespec(p->two, i, "two");
4140        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4141                p->score, p->status ? p->status : '?',
4142                p->one->rename_used, p->broken_pair);
4143}
4144
4145void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4146{
4147        int i;
4148        if (msg)
4149                fprintf(stderr, "%s\n", msg);
4150        fprintf(stderr, "q->nr = %d\n", q->nr);
4151        for (i = 0; i < q->nr; i++) {
4152                struct diff_filepair *p = q->queue[i];
4153                diff_debug_filepair(p, i);
4154        }
4155}
4156#endif
4157
4158static void diff_resolve_rename_copy(void)
4159{
4160        int i;
4161        struct diff_filepair *p;
4162        struct diff_queue_struct *q = &diff_queued_diff;
4163
4164        diff_debug_queue("resolve-rename-copy", q);
4165
4166        for (i = 0; i < q->nr; i++) {
4167                p = q->queue[i];
4168                p->status = 0; /* undecided */
4169                if (DIFF_PAIR_UNMERGED(p))
4170                        p->status = DIFF_STATUS_UNMERGED;
4171                else if (!DIFF_FILE_VALID(p->one))
4172                        p->status = DIFF_STATUS_ADDED;
4173                else if (!DIFF_FILE_VALID(p->two))
4174                        p->status = DIFF_STATUS_DELETED;
4175                else if (DIFF_PAIR_TYPE_CHANGED(p))
4176                        p->status = DIFF_STATUS_TYPE_CHANGED;
4177
4178                /* from this point on, we are dealing with a pair
4179                 * whose both sides are valid and of the same type, i.e.
4180                 * either in-place edit or rename/copy edit.
4181                 */
4182                else if (DIFF_PAIR_RENAME(p)) {
4183                        /*
4184                         * A rename might have re-connected a broken
4185                         * pair up, causing the pathnames to be the
4186                         * same again. If so, that's not a rename at
4187                         * all, just a modification..
4188                         *
4189                         * Otherwise, see if this source was used for
4190                         * multiple renames, in which case we decrement
4191                         * the count, and call it a copy.
4192                         */
4193                        if (!strcmp(p->one->path, p->two->path))
4194                                p->status = DIFF_STATUS_MODIFIED;
4195                        else if (--p->one->rename_used > 0)
4196                                p->status = DIFF_STATUS_COPIED;
4197                        else
4198                                p->status = DIFF_STATUS_RENAMED;
4199                }
4200                else if (hashcmp(p->one->sha1, p->two->sha1) ||
4201                         p->one->mode != p->two->mode ||
4202                         p->one->dirty_submodule ||
4203                         p->two->dirty_submodule ||
4204                         is_null_sha1(p->one->sha1))
4205                        p->status = DIFF_STATUS_MODIFIED;
4206                else {
4207                        /* This is a "no-change" entry and should not
4208                         * happen anymore, but prepare for broken callers.
4209                         */
4210                        error("feeding unmodified %s to diffcore",
4211                              p->one->path);
4212                        p->status = DIFF_STATUS_UNKNOWN;
4213                }
4214        }
4215        diff_debug_queue("resolve-rename-copy done", q);
4216}
4217
4218static int check_pair_status(struct diff_filepair *p)
4219{
4220        switch (p->status) {
4221        case DIFF_STATUS_UNKNOWN:
4222                return 0;
4223        case 0:
4224                die("internal error in diff-resolve-rename-copy");
4225        default:
4226                return 1;
4227        }
4228}
4229
4230static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4231{
4232        int fmt = opt->output_format;
4233
4234        if (fmt & DIFF_FORMAT_CHECKDIFF)
4235                diff_flush_checkdiff(p, opt);
4236        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4237                diff_flush_raw(p, opt);
4238        else if (fmt & DIFF_FORMAT_NAME) {
4239                const char *name_a, *name_b;
4240                name_a = p->two->path;
4241                name_b = NULL;
4242                strip_prefix(opt->prefix_length, &name_a, &name_b);
4243                write_name_quoted(name_a, opt->file, opt->line_termination);
4244        }
4245}
4246
4247static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4248{
4249        if (fs->mode)
4250                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4251        else
4252                fprintf(file, " %s ", newdelete);
4253        write_name_quoted(fs->path, file, '\n');
4254}
4255
4256
4257static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4258                const char *line_prefix)
4259{
4260        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4261                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4262                        p->two->mode, show_name ? ' ' : '\n');
4263                if (show_name) {
4264                        write_name_quoted(p->two->path, file, '\n');
4265                }
4266        }
4267}
4268
4269static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4270                        const char *line_prefix)
4271{
4272        char *names = pprint_rename(p->one->path, p->two->path);
4273
4274        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4275        free(names);
4276        show_mode_change(file, p, 0, line_prefix);
4277}
4278
4279static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4280{
4281        FILE *file = opt->file;
4282        const char *line_prefix = diff_line_prefix(opt);
4283
4284        switch(p->status) {
4285        case DIFF_STATUS_DELETED:
4286                fputs(line_prefix, file);
4287                show_file_mode_name(file, "delete", p->one);
4288                break;
4289        case DIFF_STATUS_ADDED:
4290                fputs(line_prefix, file);
4291                show_file_mode_name(file, "create", p->two);
4292                break;
4293        case DIFF_STATUS_COPIED:
4294                fputs(line_prefix, file);
4295                show_rename_copy(file, "copy", p, line_prefix);
4296                break;
4297        case DIFF_STATUS_RENAMED:
4298                fputs(line_prefix, file);
4299                show_rename_copy(file, "rename", p, line_prefix);
4300                break;
4301        default:
4302                if (p->score) {
4303                        fprintf(file, "%s rewrite ", line_prefix);
4304                        write_name_quoted(p->two->path, file, ' ');
4305                        fprintf(file, "(%d%%)\n", similarity_index(p));
4306                }
4307                show_mode_change(file, p, !p->score, line_prefix);
4308                break;
4309        }
4310}
4311
4312struct patch_id_t {
4313        git_SHA_CTX *ctx;
4314        int patchlen;
4315};
4316
4317static int remove_space(char *line, int len)
4318{
4319        int i;
4320        char *dst = line;
4321        unsigned char c;
4322
4323        for (i = 0; i < len; i++)
4324                if (!isspace((c = line[i])))
4325                        *dst++ = c;
4326
4327        return dst - line;
4328}
4329
4330static void patch_id_consume(void *priv, char *line, unsigned long len)
4331{
4332        struct patch_id_t *data = priv;
4333        int new_len;
4334
4335        /* Ignore line numbers when computing the SHA1 of the patch */
4336        if (starts_with(line, "@@ -"))
4337                return;
4338
4339        new_len = remove_space(line, len);
4340
4341        git_SHA1_Update(data->ctx, line, new_len);
4342        data->patchlen += new_len;
4343}
4344
4345/* returns 0 upon success, and writes result into sha1 */
4346static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
4347{
4348        struct diff_queue_struct *q = &diff_queued_diff;
4349        int i;
4350        git_SHA_CTX ctx;
4351        struct patch_id_t data;
4352        char buffer[PATH_MAX * 4 + 20];
4353
4354        git_SHA1_Init(&ctx);
4355        memset(&data, 0, sizeof(struct patch_id_t));
4356        data.ctx = &ctx;
4357
4358        for (i = 0; i < q->nr; i++) {
4359                xpparam_t xpp;
4360                xdemitconf_t xecfg;
4361                mmfile_t mf1, mf2;
4362                struct diff_filepair *p = q->queue[i];
4363                int len1, len2;
4364
4365                memset(&xpp, 0, sizeof(xpp));
4366                memset(&xecfg, 0, sizeof(xecfg));
4367                if (p->status == 0)
4368                        return error("internal diff status error");
4369                if (p->status == DIFF_STATUS_UNKNOWN)
4370                        continue;
4371                if (diff_unmodified_pair(p))
4372                        continue;
4373                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4374                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4375                        continue;
4376                if (DIFF_PAIR_UNMERGED(p))
4377                        continue;
4378
4379                diff_fill_sha1_info(p->one);
4380                diff_fill_sha1_info(p->two);
4381                if (fill_mmfile(&mf1, p->one) < 0 ||
4382                                fill_mmfile(&mf2, p->two) < 0)
4383                        return error("unable to read files to diff");
4384
4385                len1 = remove_space(p->one->path, strlen(p->one->path));
4386                len2 = remove_space(p->two->path, strlen(p->two->path));
4387                if (p->one->mode == 0)
4388                        len1 = snprintf(buffer, sizeof(buffer),
4389                                        "diff--gita/%.*sb/%.*s"
4390                                        "newfilemode%06o"
4391                                        "---/dev/null"
4392                                        "+++b/%.*s",
4393                                        len1, p->one->path,
4394                                        len2, p->two->path,
4395                                        p->two->mode,
4396                                        len2, p->two->path);
4397                else if (p->two->mode == 0)
4398                        len1 = snprintf(buffer, sizeof(buffer),
4399                                        "diff--gita/%.*sb/%.*s"
4400                                        "deletedfilemode%06o"
4401                                        "---a/%.*s"
4402                                        "+++/dev/null",
4403                                        len1, p->one->path,
4404                                        len2, p->two->path,
4405                                        p->one->mode,
4406                                        len1, p->one->path);
4407                else
4408                        len1 = snprintf(buffer, sizeof(buffer),
4409                                        "diff--gita/%.*sb/%.*s"
4410                                        "---a/%.*s"
4411                                        "+++b/%.*s",
4412                                        len1, p->one->path,
4413                                        len2, p->two->path,
4414                                        len1, p->one->path,
4415                                        len2, p->two->path);
4416                git_SHA1_Update(&ctx, buffer, len1);
4417
4418                if (diff_filespec_is_binary(p->one) ||
4419                    diff_filespec_is_binary(p->two)) {
4420                        git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4421                        git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4422                        continue;
4423                }
4424
4425                xpp.flags = 0;
4426                xecfg.ctxlen = 3;
4427                xecfg.flags = 0;
4428                xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4429                              &xpp, &xecfg);
4430        }
4431
4432        git_SHA1_Final(sha1, &ctx);
4433        return 0;
4434}
4435
4436int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4437{
4438        struct diff_queue_struct *q = &diff_queued_diff;
4439        int i;
4440        int result = diff_get_patch_id(options, sha1);
4441
4442        for (i = 0; i < q->nr; i++)
4443                diff_free_filepair(q->queue[i]);
4444
4445        free(q->queue);
4446        DIFF_QUEUE_CLEAR(q);
4447
4448        return result;
4449}
4450
4451static int is_summary_empty(const struct diff_queue_struct *q)
4452{
4453        int i;
4454
4455        for (i = 0; i < q->nr; i++) {
4456                const struct diff_filepair *p = q->queue[i];
4457
4458                switch (p->status) {
4459                case DIFF_STATUS_DELETED:
4460                case DIFF_STATUS_ADDED:
4461                case DIFF_STATUS_COPIED:
4462                case DIFF_STATUS_RENAMED:
4463                        return 0;
4464                default:
4465                        if (p->score)
4466                                return 0;
4467                        if (p->one->mode && p->two->mode &&
4468                            p->one->mode != p->two->mode)
4469                                return 0;
4470                        break;
4471                }
4472        }
4473        return 1;
4474}
4475
4476static const char rename_limit_warning[] =
4477"inexact rename detection was skipped due to too many files.";
4478
4479static const char degrade_cc_to_c_warning[] =
4480"only found copies from modified paths due to too many files.";
4481
4482static const char rename_limit_advice[] =
4483"you may want to set your %s variable to at least "
4484"%d and retry the command.";
4485
4486void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4487{
4488        if (degraded_cc)
4489                warning(degrade_cc_to_c_warning);
4490        else if (needed)
4491                warning(rename_limit_warning);
4492        else
4493                return;
4494        if (0 < needed && needed < 32767)
4495                warning(rename_limit_advice, varname, needed);
4496}
4497
4498void diff_flush(struct diff_options *options)
4499{
4500        struct diff_queue_struct *q = &diff_queued_diff;
4501        int i, output_format = options->output_format;
4502        int separator = 0;
4503        int dirstat_by_line = 0;
4504
4505        /*
4506         * Order: raw, stat, summary, patch
4507         * or:    name/name-status/checkdiff (other bits clear)
4508         */
4509        if (!q->nr)
4510                goto free_queue;
4511
4512        if (output_format & (DIFF_FORMAT_RAW |
4513                             DIFF_FORMAT_NAME |
4514                             DIFF_FORMAT_NAME_STATUS |
4515                             DIFF_FORMAT_CHECKDIFF)) {
4516                for (i = 0; i < q->nr; i++) {
4517                        struct diff_filepair *p = q->queue[i];
4518                        if (check_pair_status(p))
4519                                flush_one_pair(p, options);
4520                }
4521                separator++;
4522        }
4523
4524        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4525                dirstat_by_line = 1;
4526
4527        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4528            dirstat_by_line) {
4529                struct diffstat_t diffstat;
4530
4531                memset(&diffstat, 0, sizeof(struct diffstat_t));
4532                for (i = 0; i < q->nr; i++) {
4533                        struct diff_filepair *p = q->queue[i];
4534                        if (check_pair_status(p))
4535                                diff_flush_stat(p, options, &diffstat);
4536                }
4537                if (output_format & DIFF_FORMAT_NUMSTAT)
4538                        show_numstat(&diffstat, options);
4539                if (output_format & DIFF_FORMAT_DIFFSTAT)
4540                        show_stats(&diffstat, options);
4541                if (output_format & DIFF_FORMAT_SHORTSTAT)
4542                        show_shortstats(&diffstat, options);
4543                if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
4544                        show_dirstat_by_line(&diffstat, options);
4545                free_diffstat_info(&diffstat);
4546                separator++;
4547        }
4548        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4549                show_dirstat(options);
4550
4551        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4552                for (i = 0; i < q->nr; i++) {
4553                        diff_summary(options, q->queue[i]);
4554                }
4555                separator++;
4556        }
4557
4558        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4559            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4560            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4561                /*
4562                 * run diff_flush_patch for the exit status. setting
4563                 * options->file to /dev/null should be safe, because we
4564                 * aren't supposed to produce any output anyway.
4565                 */
4566                if (options->close_file)
4567                        fclose(options->file);
4568                options->file = fopen("/dev/null", "w");
4569                if (!options->file)
4570                        die_errno("Could not open /dev/null");
4571                options->close_file = 1;
4572                for (i = 0; i < q->nr; i++) {
4573                        struct diff_filepair *p = q->queue[i];
4574                        if (check_pair_status(p))
4575                                diff_flush_patch(p, options);
4576                        if (options->found_changes)
4577                                break;
4578                }
4579        }
4580
4581        if (output_format & DIFF_FORMAT_PATCH) {
4582                if (separator) {
4583                        fprintf(options->file, "%s%c",
4584                                diff_line_prefix(options),
4585                                options->line_termination);
4586                        if (options->stat_sep) {
4587                                /* attach patch instead of inline */
4588                                fputs(options->stat_sep, options->file);
4589                        }
4590                }
4591
4592                for (i = 0; i < q->nr; i++) {
4593                        struct diff_filepair *p = q->queue[i];
4594                        if (check_pair_status(p))
4595                                diff_flush_patch(p, options);
4596                }
4597        }
4598
4599        if (output_format & DIFF_FORMAT_CALLBACK)
4600                options->format_callback(q, options, options->format_callback_data);
4601
4602        for (i = 0; i < q->nr; i++)
4603                diff_free_filepair(q->queue[i]);
4604free_queue:
4605        free(q->queue);
4606        DIFF_QUEUE_CLEAR(q);
4607        if (options->close_file)
4608                fclose(options->file);
4609
4610        /*
4611         * Report the content-level differences with HAS_CHANGES;
4612         * diff_addremove/diff_change does not set the bit when
4613         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4614         */
4615        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4616                if (options->found_changes)
4617                        DIFF_OPT_SET(options, HAS_CHANGES);
4618                else
4619                        DIFF_OPT_CLR(options, HAS_CHANGES);
4620        }
4621}
4622
4623static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
4624{
4625        return (((p->status == DIFF_STATUS_MODIFIED) &&
4626                 ((p->score &&
4627                   filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
4628                  (!p->score &&
4629                   filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
4630                ((p->status != DIFF_STATUS_MODIFIED) &&
4631                 filter_bit_tst(p->status, options)));
4632}
4633
4634static void diffcore_apply_filter(struct diff_options *options)
4635{
4636        int i;
4637        struct diff_queue_struct *q = &diff_queued_diff;
4638        struct diff_queue_struct outq;
4639
4640        DIFF_QUEUE_CLEAR(&outq);
4641
4642        if (!options->filter)
4643                return;
4644
4645        if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
4646                int found;
4647                for (i = found = 0; !found && i < q->nr; i++) {
4648                        if (match_filter(options, q->queue[i]))
4649                                found++;
4650                }
4651                if (found)
4652                        return;
4653
4654                /* otherwise we will clear the whole queue
4655                 * by copying the empty outq at the end of this
4656                 * function, but first clear the current entries
4657                 * in the queue.
4658                 */
4659                for (i = 0; i < q->nr; i++)
4660                        diff_free_filepair(q->queue[i]);
4661        }
4662        else {
4663                /* Only the matching ones */
4664                for (i = 0; i < q->nr; i++) {
4665                        struct diff_filepair *p = q->queue[i];
4666                        if (match_filter(options, p))
4667                                diff_q(&outq, p);
4668                        else
4669                                diff_free_filepair(p);
4670                }
4671        }
4672        free(q->queue);
4673        *q = outq;
4674}
4675
4676/* Check whether two filespecs with the same mode and size are identical */
4677static int diff_filespec_is_identical(struct diff_filespec *one,
4678                                      struct diff_filespec *two)
4679{
4680        if (S_ISGITLINK(one->mode))
4681                return 0;
4682        if (diff_populate_filespec(one, 0))
4683                return 0;
4684        if (diff_populate_filespec(two, 0))
4685                return 0;
4686        return !memcmp(one->data, two->data, one->size);
4687}
4688
4689static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
4690{
4691        if (p->done_skip_stat_unmatch)
4692                return p->skip_stat_unmatch_result;
4693
4694        p->done_skip_stat_unmatch = 1;
4695        p->skip_stat_unmatch_result = 0;
4696        /*
4697         * 1. Entries that come from stat info dirtiness
4698         *    always have both sides (iow, not create/delete),
4699         *    one side of the object name is unknown, with
4700         *    the same mode and size.  Keep the ones that
4701         *    do not match these criteria.  They have real
4702         *    differences.
4703         *
4704         * 2. At this point, the file is known to be modified,
4705         *    with the same mode and size, and the object
4706         *    name of one side is unknown.  Need to inspect
4707         *    the identical contents.
4708         */
4709        if (!DIFF_FILE_VALID(p->one) || /* (1) */
4710            !DIFF_FILE_VALID(p->two) ||
4711            (p->one->sha1_valid && p->two->sha1_valid) ||
4712            (p->one->mode != p->two->mode) ||
4713            diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
4714            diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
4715            (p->one->size != p->two->size) ||
4716            !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4717                p->skip_stat_unmatch_result = 1;
4718        return p->skip_stat_unmatch_result;
4719}
4720
4721static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4722{
4723        int i;
4724        struct diff_queue_struct *q = &diff_queued_diff;
4725        struct diff_queue_struct outq;
4726        DIFF_QUEUE_CLEAR(&outq);
4727
4728        for (i = 0; i < q->nr; i++) {
4729                struct diff_filepair *p = q->queue[i];
4730
4731                if (diff_filespec_check_stat_unmatch(p))
4732                        diff_q(&outq, p);
4733                else {
4734                        /*
4735                         * The caller can subtract 1 from skip_stat_unmatch
4736                         * to determine how many paths were dirty only
4737                         * due to stat info mismatch.
4738                         */
4739                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4740                                diffopt->skip_stat_unmatch++;
4741                        diff_free_filepair(p);
4742                }
4743        }
4744        free(q->queue);
4745        *q = outq;
4746}
4747
4748static int diffnamecmp(const void *a_, const void *b_)
4749{
4750        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4751        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4752        const char *name_a, *name_b;
4753
4754        name_a = a->one ? a->one->path : a->two->path;
4755        name_b = b->one ? b->one->path : b->two->path;
4756        return strcmp(name_a, name_b);
4757}
4758
4759void diffcore_fix_diff_index(struct diff_options *options)
4760{
4761        struct diff_queue_struct *q = &diff_queued_diff;
4762        qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4763}
4764
4765void diffcore_std(struct diff_options *options)
4766{
4767        /* NOTE please keep the following in sync with diff_tree_combined() */
4768        if (options->skip_stat_unmatch)
4769                diffcore_skip_stat_unmatch(options);
4770        if (!options->found_follow) {
4771                /* See try_to_follow_renames() in tree-diff.c */
4772                if (options->break_opt != -1)
4773                        diffcore_break(options->break_opt);
4774                if (options->detect_rename)
4775                        diffcore_rename(options);
4776                if (options->break_opt != -1)
4777                        diffcore_merge_broken();
4778        }
4779        if (options->pickaxe)
4780                diffcore_pickaxe(options);
4781        if (options->orderfile)
4782                diffcore_order(options->orderfile);
4783        if (!options->found_follow)
4784                /* See try_to_follow_renames() in tree-diff.c */
4785                diff_resolve_rename_copy();
4786        diffcore_apply_filter(options);
4787
4788        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4789                DIFF_OPT_SET(options, HAS_CHANGES);
4790        else
4791                DIFF_OPT_CLR(options, HAS_CHANGES);
4792
4793        options->found_follow = 0;
4794}
4795
4796int diff_result_code(struct diff_options *opt, int status)
4797{
4798        int result = 0;
4799
4800        diff_warn_rename_limit("diff.renameLimit",
4801                               opt->needed_rename_limit,
4802                               opt->degraded_cc_to_c);
4803        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4804            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4805                return status;
4806        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4807            DIFF_OPT_TST(opt, HAS_CHANGES))
4808                result |= 01;
4809        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4810            DIFF_OPT_TST(opt, CHECK_FAILED))
4811                result |= 02;
4812        return result;
4813}
4814
4815int diff_can_quit_early(struct diff_options *opt)
4816{
4817        return (DIFF_OPT_TST(opt, QUICK) &&
4818                !opt->filter &&
4819                DIFF_OPT_TST(opt, HAS_CHANGES));
4820}
4821
4822/*
4823 * Shall changes to this submodule be ignored?
4824 *
4825 * Submodule changes can be configured to be ignored separately for each path,
4826 * but that configuration can be overridden from the command line.
4827 */
4828static int is_submodule_ignored(const char *path, struct diff_options *options)
4829{
4830        int ignored = 0;
4831        unsigned orig_flags = options->flags;
4832        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4833                set_diffopt_flags_from_submodule_config(options, path);
4834        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4835                ignored = 1;
4836        options->flags = orig_flags;
4837        return ignored;
4838}
4839
4840void diff_addremove(struct diff_options *options,
4841                    int addremove, unsigned mode,
4842                    const unsigned char *sha1,
4843                    int sha1_valid,
4844                    const char *concatpath, unsigned dirty_submodule)
4845{
4846        struct diff_filespec *one, *two;
4847
4848        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4849                return;
4850
4851        /* This may look odd, but it is a preparation for
4852         * feeding "there are unchanged files which should
4853         * not produce diffs, but when you are doing copy
4854         * detection you would need them, so here they are"
4855         * entries to the diff-core.  They will be prefixed
4856         * with something like '=' or '*' (I haven't decided
4857         * which but should not make any difference).
4858         * Feeding the same new and old to diff_change()
4859         * also has the same effect.
4860         * Before the final output happens, they are pruned after
4861         * merged into rename/copy pairs as appropriate.
4862         */
4863        if (DIFF_OPT_TST(options, REVERSE_DIFF))
4864                addremove = (addremove == '+' ? '-' :
4865                             addremove == '-' ? '+' : addremove);
4866
4867        if (options->prefix &&
4868            strncmp(concatpath, options->prefix, options->prefix_length))
4869                return;
4870
4871        one = alloc_filespec(concatpath);
4872        two = alloc_filespec(concatpath);
4873
4874        if (addremove != '+')
4875                fill_filespec(one, sha1, sha1_valid, mode);
4876        if (addremove != '-') {
4877                fill_filespec(two, sha1, sha1_valid, mode);
4878                two->dirty_submodule = dirty_submodule;
4879        }
4880
4881        diff_queue(&diff_queued_diff, one, two);
4882        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4883                DIFF_OPT_SET(options, HAS_CHANGES);
4884}
4885
4886void diff_change(struct diff_options *options,
4887                 unsigned old_mode, unsigned new_mode,
4888                 const unsigned char *old_sha1,
4889                 const unsigned char *new_sha1,
4890                 int old_sha1_valid, int new_sha1_valid,
4891                 const char *concatpath,
4892                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4893{
4894        struct diff_filespec *one, *two;
4895        struct diff_filepair *p;
4896
4897        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4898            is_submodule_ignored(concatpath, options))
4899                return;
4900
4901        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4902                unsigned tmp;
4903                const unsigned char *tmp_c;
4904                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
4905                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
4906                tmp = old_sha1_valid; old_sha1_valid = new_sha1_valid;
4907                        new_sha1_valid = tmp;
4908                tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
4909                        new_dirty_submodule = tmp;
4910        }
4911
4912        if (options->prefix &&
4913            strncmp(concatpath, options->prefix, options->prefix_length))
4914                return;
4915
4916        one = alloc_filespec(concatpath);
4917        two = alloc_filespec(concatpath);
4918        fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
4919        fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
4920        one->dirty_submodule = old_dirty_submodule;
4921        two->dirty_submodule = new_dirty_submodule;
4922        p = diff_queue(&diff_queued_diff, one, two);
4923
4924        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4925                return;
4926
4927        if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
4928            !diff_filespec_check_stat_unmatch(p))
4929                return;
4930
4931        DIFF_OPT_SET(options, HAS_CHANGES);
4932}
4933
4934struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
4935{
4936        struct diff_filepair *pair;
4937        struct diff_filespec *one, *two;
4938
4939        if (options->prefix &&
4940            strncmp(path, options->prefix, options->prefix_length))
4941                return NULL;
4942
4943        one = alloc_filespec(path);
4944        two = alloc_filespec(path);
4945        pair = diff_queue(&diff_queued_diff, one, two);
4946        pair->is_unmerged = 1;
4947        return pair;
4948}
4949
4950static char *run_textconv(const char *pgm, struct diff_filespec *spec,
4951                size_t *outsize)
4952{
4953        struct diff_tempfile *temp;
4954        const char *argv[3];
4955        const char **arg = argv;
4956        struct child_process child = CHILD_PROCESS_INIT;
4957        struct strbuf buf = STRBUF_INIT;
4958        int err = 0;
4959
4960        temp = prepare_temp_file(spec->path, spec);
4961        *arg++ = pgm;
4962        *arg++ = temp->name;
4963        *arg = NULL;
4964
4965        child.use_shell = 1;
4966        child.argv = argv;
4967        child.out = -1;
4968        if (start_command(&child)) {
4969                remove_tempfile();
4970                return NULL;
4971        }
4972
4973        if (strbuf_read(&buf, child.out, 0) < 0)
4974                err = error("error reading from textconv command '%s'", pgm);
4975        close(child.out);
4976
4977        if (finish_command(&child) || err) {
4978                strbuf_release(&buf);
4979                remove_tempfile();
4980                return NULL;
4981        }
4982        remove_tempfile();
4983
4984        return strbuf_detach(&buf, outsize);
4985}
4986
4987size_t fill_textconv(struct userdiff_driver *driver,
4988                     struct diff_filespec *df,
4989                     char **outbuf)
4990{
4991        size_t size;
4992
4993        if (!driver || !driver->textconv) {
4994                if (!DIFF_FILE_VALID(df)) {
4995                        *outbuf = "";
4996                        return 0;
4997                }
4998                if (diff_populate_filespec(df, 0))
4999                        die("unable to read files to diff");
5000                *outbuf = df->data;
5001                return df->size;
5002        }
5003
5004        if (driver->textconv_cache && df->sha1_valid) {
5005                *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
5006                                          &size);
5007                if (*outbuf)
5008                        return size;
5009        }
5010
5011        *outbuf = run_textconv(driver->textconv, df, &size);
5012        if (!*outbuf)
5013                die("unable to read files to diff");
5014
5015        if (driver->textconv_cache && df->sha1_valid) {
5016                /* ignore errors, as we might be in a readonly repository */
5017                notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
5018                                size);
5019                /*
5020                 * we could save up changes and flush them all at the end,
5021                 * but we would need an extra call after all diffing is done.
5022                 * Since generating a cache entry is the slow path anyway,
5023                 * this extra overhead probably isn't a big deal.
5024                 */
5025                notes_cache_write(driver->textconv_cache);
5026        }
5027
5028        return size;
5029}
5030
5031void setup_diff_pager(struct diff_options *opt)
5032{
5033        /*
5034         * If the user asked for our exit code, then either they want --quiet
5035         * or --exit-code. We should definitely not bother with a pager in the
5036         * former case, as we will generate no output. Since we still properly
5037         * report our exit code even when a pager is run, we _could_ run a
5038         * pager with --exit-code. But since we have not done so historically,
5039         * and because it is easy to find people oneline advising "git diff
5040         * --exit-code" in hooks and other scripts, we do not do so.
5041         */
5042        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5043            check_pager_config("diff") != 0)
5044                setup_pager();
5045}