diff.con commit Merge branch 'jc/am-3-fallback-regression-fix' (9c53de7)
   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-config.h"
  18#include "submodule.h"
  19#include "ll-merge.h"
  20#include "string-list.h"
  21#include "argv-array.h"
  22
  23#ifdef NO_FAST_WORKING_DIRECTORY
  24#define FAST_WORKING_DIRECTORY 0
  25#else
  26#define FAST_WORKING_DIRECTORY 1
  27#endif
  28
  29static int diff_detect_rename_default;
  30static int diff_rename_limit_default = 400;
  31static int diff_suppress_blank_empty;
  32static int diff_use_color_default = -1;
  33static int diff_context_default = 3;
  34static const char *diff_word_regex_cfg;
  35static const char *external_diff_cmd_cfg;
  36static const char *diff_order_file_cfg;
  37int diff_auto_refresh_index = 1;
  38static int diff_mnemonic_prefix;
  39static int diff_no_prefix;
  40static int diff_stat_graph_width;
  41static int diff_dirstat_permille_default = 30;
  42static struct diff_options default_diff_options;
  43static long diff_algorithm;
  44
  45static char diff_colors[][COLOR_MAXLEN] = {
  46        GIT_COLOR_RESET,
  47        GIT_COLOR_NORMAL,       /* CONTEXT */
  48        GIT_COLOR_BOLD,         /* METAINFO */
  49        GIT_COLOR_CYAN,         /* FRAGINFO */
  50        GIT_COLOR_RED,          /* OLD */
  51        GIT_COLOR_GREEN,        /* NEW */
  52        GIT_COLOR_YELLOW,       /* COMMIT */
  53        GIT_COLOR_BG_RED,       /* WHITESPACE */
  54        GIT_COLOR_NORMAL,       /* FUNCINFO */
  55};
  56
  57static int parse_diff_color_slot(const char *var)
  58{
  59        if (!strcasecmp(var, "context") || !strcasecmp(var, "plain"))
  60                return DIFF_CONTEXT;
  61        if (!strcasecmp(var, "meta"))
  62                return DIFF_METAINFO;
  63        if (!strcasecmp(var, "frag"))
  64                return DIFF_FRAGINFO;
  65        if (!strcasecmp(var, "old"))
  66                return DIFF_FILE_OLD;
  67        if (!strcasecmp(var, "new"))
  68                return DIFF_FILE_NEW;
  69        if (!strcasecmp(var, "commit"))
  70                return DIFF_COMMIT;
  71        if (!strcasecmp(var, "whitespace"))
  72                return DIFF_WHITESPACE;
  73        if (!strcasecmp(var, "func"))
  74                return DIFF_FUNCINFO;
  75        return -1;
  76}
  77
  78static int parse_dirstat_params(struct diff_options *options, const char *params_string,
  79                                struct strbuf *errmsg)
  80{
  81        char *params_copy = xstrdup(params_string);
  82        struct string_list params = STRING_LIST_INIT_NODUP;
  83        int ret = 0;
  84        int i;
  85
  86        if (*params_copy)
  87                string_list_split_in_place(&params, params_copy, ',', -1);
  88        for (i = 0; i < params.nr; i++) {
  89                const char *p = params.items[i].string;
  90                if (!strcmp(p, "changes")) {
  91                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  92                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  93                } else if (!strcmp(p, "lines")) {
  94                        DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
  95                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  96                } else if (!strcmp(p, "files")) {
  97                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  98                        DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
  99                } else if (!strcmp(p, "noncumulative")) {
 100                        DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
 101                } else if (!strcmp(p, "cumulative")) {
 102                        DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
 103                } else if (isdigit(*p)) {
 104                        char *end;
 105                        int permille = strtoul(p, &end, 10) * 10;
 106                        if (*end == '.' && isdigit(*++end)) {
 107                                /* only use first digit */
 108                                permille += *end - '0';
 109                                /* .. and ignore any further digits */
 110                                while (isdigit(*++end))
 111                                        ; /* nothing */
 112                        }
 113                        if (!*end)
 114                                options->dirstat_permille = permille;
 115                        else {
 116                                strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 117                                            p);
 118                                ret++;
 119                        }
 120                } else {
 121                        strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 122                        ret++;
 123                }
 124
 125        }
 126        string_list_clear(&params, 0);
 127        free(params_copy);
 128        return ret;
 129}
 130
 131static int parse_submodule_params(struct diff_options *options, const char *value)
 132{
 133        if (!strcmp(value, "log"))
 134                DIFF_OPT_SET(options, SUBMODULE_LOG);
 135        else if (!strcmp(value, "short"))
 136                DIFF_OPT_CLR(options, SUBMODULE_LOG);
 137        else
 138                return -1;
 139        return 0;
 140}
 141
 142static int git_config_rename(const char *var, const char *value)
 143{
 144        if (!value)
 145                return DIFF_DETECT_RENAME;
 146        if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 147                return  DIFF_DETECT_COPY;
 148        return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 149}
 150
 151long parse_algorithm_value(const char *value)
 152{
 153        if (!value)
 154                return -1;
 155        else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 156                return 0;
 157        else if (!strcasecmp(value, "minimal"))
 158                return XDF_NEED_MINIMAL;
 159        else if (!strcasecmp(value, "patience"))
 160                return XDF_PATIENCE_DIFF;
 161        else if (!strcasecmp(value, "histogram"))
 162                return XDF_HISTOGRAM_DIFF;
 163        return -1;
 164}
 165
 166/*
 167 * These are to give UI layer defaults.
 168 * The core-level commands such as git-diff-files should
 169 * never be affected by the setting of diff.renames
 170 * the user happens to have in the configuration file.
 171 */
 172int git_diff_ui_config(const char *var, const char *value, void *cb)
 173{
 174        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 175                diff_use_color_default = git_config_colorbool(var, value);
 176                return 0;
 177        }
 178        if (!strcmp(var, "diff.context")) {
 179                diff_context_default = git_config_int(var, value);
 180                if (diff_context_default < 0)
 181                        return -1;
 182                return 0;
 183        }
 184        if (!strcmp(var, "diff.renames")) {
 185                diff_detect_rename_default = git_config_rename(var, value);
 186                return 0;
 187        }
 188        if (!strcmp(var, "diff.autorefreshindex")) {
 189                diff_auto_refresh_index = git_config_bool(var, value);
 190                return 0;
 191        }
 192        if (!strcmp(var, "diff.mnemonicprefix")) {
 193                diff_mnemonic_prefix = git_config_bool(var, value);
 194                return 0;
 195        }
 196        if (!strcmp(var, "diff.noprefix")) {
 197                diff_no_prefix = git_config_bool(var, value);
 198                return 0;
 199        }
 200        if (!strcmp(var, "diff.statgraphwidth")) {
 201                diff_stat_graph_width = git_config_int(var, value);
 202                return 0;
 203        }
 204        if (!strcmp(var, "diff.external"))
 205                return git_config_string(&external_diff_cmd_cfg, var, value);
 206        if (!strcmp(var, "diff.wordregex"))
 207                return git_config_string(&diff_word_regex_cfg, var, value);
 208        if (!strcmp(var, "diff.orderfile"))
 209                return git_config_pathname(&diff_order_file_cfg, var, value);
 210
 211        if (!strcmp(var, "diff.ignoresubmodules"))
 212                handle_ignore_submodules_arg(&default_diff_options, value);
 213
 214        if (!strcmp(var, "diff.submodule")) {
 215                if (parse_submodule_params(&default_diff_options, value))
 216                        warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 217                                value);
 218                return 0;
 219        }
 220
 221        if (!strcmp(var, "diff.algorithm")) {
 222                diff_algorithm = parse_algorithm_value(value);
 223                if (diff_algorithm < 0)
 224                        return -1;
 225                return 0;
 226        }
 227
 228        if (git_color_config(var, value, cb) < 0)
 229                return -1;
 230
 231        return git_diff_basic_config(var, value, cb);
 232}
 233
 234int git_diff_basic_config(const char *var, const char *value, void *cb)
 235{
 236        const char *name;
 237
 238        if (!strcmp(var, "diff.renamelimit")) {
 239                diff_rename_limit_default = git_config_int(var, value);
 240                return 0;
 241        }
 242
 243        if (userdiff_config(var, value) < 0)
 244                return -1;
 245
 246        if (skip_prefix(var, "diff.color.", &name) ||
 247            skip_prefix(var, "color.diff.", &name)) {
 248                int slot = parse_diff_color_slot(name);
 249                if (slot < 0)
 250                        return 0;
 251                if (!value)
 252                        return config_error_nonbool(var);
 253                return color_parse(value, diff_colors[slot]);
 254        }
 255
 256        /* like GNU diff's --suppress-blank-empty option  */
 257        if (!strcmp(var, "diff.suppressblankempty") ||
 258                        /* for backwards compatibility */
 259                        !strcmp(var, "diff.suppress-blank-empty")) {
 260                diff_suppress_blank_empty = git_config_bool(var, value);
 261                return 0;
 262        }
 263
 264        if (!strcmp(var, "diff.dirstat")) {
 265                struct strbuf errmsg = STRBUF_INIT;
 266                default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 267                if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 268                        warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 269                                errmsg.buf);
 270                strbuf_release(&errmsg);
 271                diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 272                return 0;
 273        }
 274
 275        if (starts_with(var, "submodule."))
 276                return parse_submodule_config_option(var, value);
 277
 278        return git_default_config(var, value, cb);
 279}
 280
 281static char *quote_two(const char *one, const char *two)
 282{
 283        int need_one = quote_c_style(one, NULL, NULL, 1);
 284        int need_two = quote_c_style(two, NULL, NULL, 1);
 285        struct strbuf res = STRBUF_INIT;
 286
 287        if (need_one + need_two) {
 288                strbuf_addch(&res, '"');
 289                quote_c_style(one, &res, NULL, 1);
 290                quote_c_style(two, &res, NULL, 1);
 291                strbuf_addch(&res, '"');
 292        } else {
 293                strbuf_addstr(&res, one);
 294                strbuf_addstr(&res, two);
 295        }
 296        return strbuf_detach(&res, NULL);
 297}
 298
 299static const char *external_diff(void)
 300{
 301        static const char *external_diff_cmd = NULL;
 302        static int done_preparing = 0;
 303
 304        if (done_preparing)
 305                return external_diff_cmd;
 306        external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 307        if (!external_diff_cmd)
 308                external_diff_cmd = external_diff_cmd_cfg;
 309        done_preparing = 1;
 310        return external_diff_cmd;
 311}
 312
 313/*
 314 * Keep track of files used for diffing. Sometimes such an entry
 315 * refers to a temporary file, sometimes to an existing file, and
 316 * sometimes to "/dev/null".
 317 */
 318static struct diff_tempfile {
 319        /*
 320         * filename external diff should read from, or NULL if this
 321         * entry is currently not in use:
 322         */
 323        const char *name;
 324
 325        char hex[GIT_SHA1_HEXSZ + 1];
 326        char mode[10];
 327
 328        /*
 329         * If this diff_tempfile instance refers to a temporary file,
 330         * this tempfile object is used to manage its lifetime.
 331         */
 332        struct tempfile tempfile;
 333} diff_temp[2];
 334
 335typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 336
 337struct emit_callback {
 338        int color_diff;
 339        unsigned ws_rule;
 340        int blank_at_eof_in_preimage;
 341        int blank_at_eof_in_postimage;
 342        int lno_in_preimage;
 343        int lno_in_postimage;
 344        sane_truncate_fn truncate;
 345        const char **label_path;
 346        struct diff_words_data *diff_words;
 347        struct diff_options *opt;
 348        int *found_changesp;
 349        struct strbuf *header;
 350};
 351
 352static int count_lines(const char *data, int size)
 353{
 354        int count, ch, completely_empty = 1, nl_just_seen = 0;
 355        count = 0;
 356        while (0 < size--) {
 357                ch = *data++;
 358                if (ch == '\n') {
 359                        count++;
 360                        nl_just_seen = 1;
 361                        completely_empty = 0;
 362                }
 363                else {
 364                        nl_just_seen = 0;
 365                        completely_empty = 0;
 366                }
 367        }
 368        if (completely_empty)
 369                return 0;
 370        if (!nl_just_seen)
 371                count++; /* no trailing newline */
 372        return count;
 373}
 374
 375static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 376{
 377        if (!DIFF_FILE_VALID(one)) {
 378                mf->ptr = (char *)""; /* does not matter */
 379                mf->size = 0;
 380                return 0;
 381        }
 382        else if (diff_populate_filespec(one, 0))
 383                return -1;
 384
 385        mf->ptr = one->data;
 386        mf->size = one->size;
 387        return 0;
 388}
 389
 390/* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 391static unsigned long diff_filespec_size(struct diff_filespec *one)
 392{
 393        if (!DIFF_FILE_VALID(one))
 394                return 0;
 395        diff_populate_filespec(one, CHECK_SIZE_ONLY);
 396        return one->size;
 397}
 398
 399static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 400{
 401        char *ptr = mf->ptr;
 402        long size = mf->size;
 403        int cnt = 0;
 404
 405        if (!size)
 406                return cnt;
 407        ptr += size - 1; /* pointing at the very end */
 408        if (*ptr != '\n')
 409                ; /* incomplete line */
 410        else
 411                ptr--; /* skip the last LF */
 412        while (mf->ptr < ptr) {
 413                char *prev_eol;
 414                for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 415                        if (*prev_eol == '\n')
 416                                break;
 417                if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 418                        break;
 419                cnt++;
 420                ptr = prev_eol - 1;
 421        }
 422        return cnt;
 423}
 424
 425static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 426                               struct emit_callback *ecbdata)
 427{
 428        int l1, l2, at;
 429        unsigned ws_rule = ecbdata->ws_rule;
 430        l1 = count_trailing_blank(mf1, ws_rule);
 431        l2 = count_trailing_blank(mf2, ws_rule);
 432        if (l2 <= l1) {
 433                ecbdata->blank_at_eof_in_preimage = 0;
 434                ecbdata->blank_at_eof_in_postimage = 0;
 435                return;
 436        }
 437        at = count_lines(mf1->ptr, mf1->size);
 438        ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 439
 440        at = count_lines(mf2->ptr, mf2->size);
 441        ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 442}
 443
 444static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 445                        int first, const char *line, int len)
 446{
 447        int has_trailing_newline, has_trailing_carriage_return;
 448        int nofirst;
 449        FILE *file = o->file;
 450
 451        fputs(diff_line_prefix(o), file);
 452
 453        if (len == 0) {
 454                has_trailing_newline = (first == '\n');
 455                has_trailing_carriage_return = (!has_trailing_newline &&
 456                                                (first == '\r'));
 457                nofirst = has_trailing_newline || has_trailing_carriage_return;
 458        } else {
 459                has_trailing_newline = (len > 0 && line[len-1] == '\n');
 460                if (has_trailing_newline)
 461                        len--;
 462                has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 463                if (has_trailing_carriage_return)
 464                        len--;
 465                nofirst = 0;
 466        }
 467
 468        if (len || !nofirst) {
 469                fputs(set, file);
 470                if (!nofirst)
 471                        fputc(first, file);
 472                fwrite(line, len, 1, file);
 473                fputs(reset, file);
 474        }
 475        if (has_trailing_carriage_return)
 476                fputc('\r', file);
 477        if (has_trailing_newline)
 478                fputc('\n', file);
 479}
 480
 481static void emit_line(struct diff_options *o, const char *set, const char *reset,
 482                      const char *line, int len)
 483{
 484        emit_line_0(o, set, reset, line[0], line+1, len-1);
 485}
 486
 487static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 488{
 489        if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 490              ecbdata->blank_at_eof_in_preimage &&
 491              ecbdata->blank_at_eof_in_postimage &&
 492              ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 493              ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 494                return 0;
 495        return ws_blank_line(line, len, ecbdata->ws_rule);
 496}
 497
 498static void emit_line_checked(const char *reset,
 499                              struct emit_callback *ecbdata,
 500                              const char *line, int len,
 501                              enum color_diff color,
 502                              unsigned ws_error_highlight,
 503                              char sign)
 504{
 505        const char *set = diff_get_color(ecbdata->color_diff, color);
 506        const char *ws = NULL;
 507
 508        if (ecbdata->opt->ws_error_highlight & ws_error_highlight) {
 509                ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 510                if (!*ws)
 511                        ws = NULL;
 512        }
 513
 514        if (!ws)
 515                emit_line_0(ecbdata->opt, set, reset, sign, line, len);
 516        else if (sign == '+' && new_blank_line_at_eof(ecbdata, line, len))
 517                /* Blank line at EOF - paint '+' as well */
 518                emit_line_0(ecbdata->opt, ws, reset, sign, line, len);
 519        else {
 520                /* Emit just the prefix, then the rest. */
 521                emit_line_0(ecbdata->opt, set, reset, sign, "", 0);
 522                ws_check_emit(line, len, ecbdata->ws_rule,
 523                              ecbdata->opt->file, set, reset, ws);
 524        }
 525}
 526
 527static void emit_add_line(const char *reset,
 528                          struct emit_callback *ecbdata,
 529                          const char *line, int len)
 530{
 531        emit_line_checked(reset, ecbdata, line, len,
 532                          DIFF_FILE_NEW, WSEH_NEW, '+');
 533}
 534
 535static void emit_del_line(const char *reset,
 536                          struct emit_callback *ecbdata,
 537                          const char *line, int len)
 538{
 539        emit_line_checked(reset, ecbdata, line, len,
 540                          DIFF_FILE_OLD, WSEH_OLD, '-');
 541}
 542
 543static void emit_context_line(const char *reset,
 544                              struct emit_callback *ecbdata,
 545                              const char *line, int len)
 546{
 547        emit_line_checked(reset, ecbdata, line, len,
 548                          DIFF_CONTEXT, WSEH_CONTEXT, ' ');
 549}
 550
 551static void emit_hunk_header(struct emit_callback *ecbdata,
 552                             const char *line, int len)
 553{
 554        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
 555        const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 556        const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 557        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 558        static const char atat[2] = { '@', '@' };
 559        const char *cp, *ep;
 560        struct strbuf msgbuf = STRBUF_INIT;
 561        int org_len = len;
 562        int i = 1;
 563
 564        /*
 565         * As a hunk header must begin with "@@ -<old>, +<new> @@",
 566         * it always is at least 10 bytes long.
 567         */
 568        if (len < 10 ||
 569            memcmp(line, atat, 2) ||
 570            !(ep = memmem(line + 2, len - 2, atat, 2))) {
 571                emit_line(ecbdata->opt, context, reset, line, len);
 572                return;
 573        }
 574        ep += 2; /* skip over @@ */
 575
 576        /* The hunk header in fraginfo color */
 577        strbuf_addstr(&msgbuf, frag);
 578        strbuf_add(&msgbuf, line, ep - line);
 579        strbuf_addstr(&msgbuf, reset);
 580
 581        /*
 582         * trailing "\r\n"
 583         */
 584        for ( ; i < 3; i++)
 585                if (line[len - i] == '\r' || line[len - i] == '\n')
 586                        len--;
 587
 588        /* blank before the func header */
 589        for (cp = ep; ep - line < len; ep++)
 590                if (*ep != ' ' && *ep != '\t')
 591                        break;
 592        if (ep != cp) {
 593                strbuf_addstr(&msgbuf, context);
 594                strbuf_add(&msgbuf, cp, ep - cp);
 595                strbuf_addstr(&msgbuf, reset);
 596        }
 597
 598        if (ep < line + len) {
 599                strbuf_addstr(&msgbuf, func);
 600                strbuf_add(&msgbuf, ep, line + len - ep);
 601                strbuf_addstr(&msgbuf, reset);
 602        }
 603
 604        strbuf_add(&msgbuf, line + len, org_len - len);
 605        emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 606        strbuf_release(&msgbuf);
 607}
 608
 609static struct diff_tempfile *claim_diff_tempfile(void) {
 610        int i;
 611        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 612                if (!diff_temp[i].name)
 613                        return diff_temp + i;
 614        die("BUG: diff is failing to clean up its tempfiles");
 615}
 616
 617static void remove_tempfile(void)
 618{
 619        int i;
 620        for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 621                if (is_tempfile_active(&diff_temp[i].tempfile))
 622                        delete_tempfile(&diff_temp[i].tempfile);
 623                diff_temp[i].name = NULL;
 624        }
 625}
 626
 627static void print_line_count(FILE *file, int count)
 628{
 629        switch (count) {
 630        case 0:
 631                fprintf(file, "0,0");
 632                break;
 633        case 1:
 634                fprintf(file, "1");
 635                break;
 636        default:
 637                fprintf(file, "1,%d", count);
 638                break;
 639        }
 640}
 641
 642static void emit_rewrite_lines(struct emit_callback *ecb,
 643                               int prefix, const char *data, int size)
 644{
 645        const char *endp = NULL;
 646        static const char *nneof = " No newline at end of file\n";
 647        const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 648
 649        while (0 < size) {
 650                int len;
 651
 652                endp = memchr(data, '\n', size);
 653                len = endp ? (endp - data + 1) : size;
 654                if (prefix != '+') {
 655                        ecb->lno_in_preimage++;
 656                        emit_del_line(reset, ecb, data, len);
 657                } else {
 658                        ecb->lno_in_postimage++;
 659                        emit_add_line(reset, ecb, data, len);
 660                }
 661                size -= len;
 662                data += len;
 663        }
 664        if (!endp) {
 665                const char *context = diff_get_color(ecb->color_diff,
 666                                                     DIFF_CONTEXT);
 667                putc('\n', ecb->opt->file);
 668                emit_line_0(ecb->opt, context, reset, '\\',
 669                            nneof, strlen(nneof));
 670        }
 671}
 672
 673static void emit_rewrite_diff(const char *name_a,
 674                              const char *name_b,
 675                              struct diff_filespec *one,
 676                              struct diff_filespec *two,
 677                              struct userdiff_driver *textconv_one,
 678                              struct userdiff_driver *textconv_two,
 679                              struct diff_options *o)
 680{
 681        int lc_a, lc_b;
 682        const char *name_a_tab, *name_b_tab;
 683        const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 684        const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 685        const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 686        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 687        const char *a_prefix, *b_prefix;
 688        char *data_one, *data_two;
 689        size_t size_one, size_two;
 690        struct emit_callback ecbdata;
 691        const char *line_prefix = diff_line_prefix(o);
 692
 693        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 694                a_prefix = o->b_prefix;
 695                b_prefix = o->a_prefix;
 696        } else {
 697                a_prefix = o->a_prefix;
 698                b_prefix = o->b_prefix;
 699        }
 700
 701        name_a += (*name_a == '/');
 702        name_b += (*name_b == '/');
 703        name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 704        name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 705
 706        strbuf_reset(&a_name);
 707        strbuf_reset(&b_name);
 708        quote_two_c_style(&a_name, a_prefix, name_a, 0);
 709        quote_two_c_style(&b_name, b_prefix, name_b, 0);
 710
 711        size_one = fill_textconv(textconv_one, one, &data_one);
 712        size_two = fill_textconv(textconv_two, two, &data_two);
 713
 714        memset(&ecbdata, 0, sizeof(ecbdata));
 715        ecbdata.color_diff = want_color(o->use_color);
 716        ecbdata.found_changesp = &o->found_changes;
 717        ecbdata.ws_rule = whitespace_rule(name_b);
 718        ecbdata.opt = o;
 719        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 720                mmfile_t mf1, mf2;
 721                mf1.ptr = (char *)data_one;
 722                mf2.ptr = (char *)data_two;
 723                mf1.size = size_one;
 724                mf2.size = size_two;
 725                check_blank_at_eof(&mf1, &mf2, &ecbdata);
 726        }
 727        ecbdata.lno_in_preimage = 1;
 728        ecbdata.lno_in_postimage = 1;
 729
 730        lc_a = count_lines(data_one, size_one);
 731        lc_b = count_lines(data_two, size_two);
 732        fprintf(o->file,
 733                "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 734                line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 735                line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 736                line_prefix, fraginfo);
 737        if (!o->irreversible_delete)
 738                print_line_count(o->file, lc_a);
 739        else
 740                fprintf(o->file, "?,?");
 741        fprintf(o->file, " +");
 742        print_line_count(o->file, lc_b);
 743        fprintf(o->file, " @@%s\n", reset);
 744        if (lc_a && !o->irreversible_delete)
 745                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 746        if (lc_b)
 747                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 748        if (textconv_one)
 749                free((char *)data_one);
 750        if (textconv_two)
 751                free((char *)data_two);
 752}
 753
 754struct diff_words_buffer {
 755        mmfile_t text;
 756        long alloc;
 757        struct diff_words_orig {
 758                const char *begin, *end;
 759        } *orig;
 760        int orig_nr, orig_alloc;
 761};
 762
 763static void diff_words_append(char *line, unsigned long len,
 764                struct diff_words_buffer *buffer)
 765{
 766        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 767        line++;
 768        len--;
 769        memcpy(buffer->text.ptr + buffer->text.size, line, len);
 770        buffer->text.size += len;
 771        buffer->text.ptr[buffer->text.size] = '\0';
 772}
 773
 774struct diff_words_style_elem {
 775        const char *prefix;
 776        const char *suffix;
 777        const char *color; /* NULL; filled in by the setup code if
 778                            * color is enabled */
 779};
 780
 781struct diff_words_style {
 782        enum diff_words_type type;
 783        struct diff_words_style_elem new, old, ctx;
 784        const char *newline;
 785};
 786
 787static struct diff_words_style diff_words_styles[] = {
 788        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 789        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 790        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 791};
 792
 793struct diff_words_data {
 794        struct diff_words_buffer minus, plus;
 795        const char *current_plus;
 796        int last_minus;
 797        struct diff_options *opt;
 798        regex_t *word_regex;
 799        enum diff_words_type type;
 800        struct diff_words_style *style;
 801};
 802
 803static int fn_out_diff_words_write_helper(FILE *fp,
 804                                          struct diff_words_style_elem *st_el,
 805                                          const char *newline,
 806                                          size_t count, const char *buf,
 807                                          const char *line_prefix)
 808{
 809        int print = 0;
 810
 811        while (count) {
 812                char *p = memchr(buf, '\n', count);
 813                if (print)
 814                        fputs(line_prefix, fp);
 815                if (p != buf) {
 816                        if (st_el->color && fputs(st_el->color, fp) < 0)
 817                                return -1;
 818                        if (fputs(st_el->prefix, fp) < 0 ||
 819                            fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 820                            fputs(st_el->suffix, fp) < 0)
 821                                return -1;
 822                        if (st_el->color && *st_el->color
 823                            && fputs(GIT_COLOR_RESET, fp) < 0)
 824                                return -1;
 825                }
 826                if (!p)
 827                        return 0;
 828                if (fputs(newline, fp) < 0)
 829                        return -1;
 830                count -= p + 1 - buf;
 831                buf = p + 1;
 832                print = 1;
 833        }
 834        return 0;
 835}
 836
 837/*
 838 * '--color-words' algorithm can be described as:
 839 *
 840 *   1. collect a the minus/plus lines of a diff hunk, divided into
 841 *      minus-lines and plus-lines;
 842 *
 843 *   2. break both minus-lines and plus-lines into words and
 844 *      place them into two mmfile_t with one word for each line;
 845 *
 846 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 847 *
 848 * And for the common parts of the both file, we output the plus side text.
 849 * diff_words->current_plus is used to trace the current position of the plus file
 850 * which printed. diff_words->last_minus is used to trace the last minus word
 851 * printed.
 852 *
 853 * For '--graph' to work with '--color-words', we need to output the graph prefix
 854 * on each line of color words output. Generally, there are two conditions on
 855 * which we should output the prefix.
 856 *
 857 *   1. diff_words->last_minus == 0 &&
 858 *      diff_words->current_plus == diff_words->plus.text.ptr
 859 *
 860 *      that is: the plus text must start as a new line, and if there is no minus
 861 *      word printed, a graph prefix must be printed.
 862 *
 863 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 864 *      *(diff_words->current_plus - 1) == '\n'
 865 *
 866 *      that is: a graph prefix must be printed following a '\n'
 867 */
 868static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 869{
 870        if ((diff_words->last_minus == 0 &&
 871                diff_words->current_plus == diff_words->plus.text.ptr) ||
 872                (diff_words->current_plus > diff_words->plus.text.ptr &&
 873                *(diff_words->current_plus - 1) == '\n')) {
 874                return 1;
 875        } else {
 876                return 0;
 877        }
 878}
 879
 880static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 881{
 882        struct diff_words_data *diff_words = priv;
 883        struct diff_words_style *style = diff_words->style;
 884        int minus_first, minus_len, plus_first, plus_len;
 885        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 886        struct diff_options *opt = diff_words->opt;
 887        const char *line_prefix;
 888
 889        if (line[0] != '@' || parse_hunk_header(line, len,
 890                        &minus_first, &minus_len, &plus_first, &plus_len))
 891                return;
 892
 893        assert(opt);
 894        line_prefix = diff_line_prefix(opt);
 895
 896        /* POSIX requires that first be decremented by one if len == 0... */
 897        if (minus_len) {
 898                minus_begin = diff_words->minus.orig[minus_first].begin;
 899                minus_end =
 900                        diff_words->minus.orig[minus_first + minus_len - 1].end;
 901        } else
 902                minus_begin = minus_end =
 903                        diff_words->minus.orig[minus_first].end;
 904
 905        if (plus_len) {
 906                plus_begin = diff_words->plus.orig[plus_first].begin;
 907                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 908        } else
 909                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 910
 911        if (color_words_output_graph_prefix(diff_words)) {
 912                fputs(line_prefix, diff_words->opt->file);
 913        }
 914        if (diff_words->current_plus != plus_begin) {
 915                fn_out_diff_words_write_helper(diff_words->opt->file,
 916                                &style->ctx, style->newline,
 917                                plus_begin - diff_words->current_plus,
 918                                diff_words->current_plus, line_prefix);
 919                if (*(plus_begin - 1) == '\n')
 920                        fputs(line_prefix, diff_words->opt->file);
 921        }
 922        if (minus_begin != minus_end) {
 923                fn_out_diff_words_write_helper(diff_words->opt->file,
 924                                &style->old, style->newline,
 925                                minus_end - minus_begin, minus_begin,
 926                                line_prefix);
 927        }
 928        if (plus_begin != plus_end) {
 929                fn_out_diff_words_write_helper(diff_words->opt->file,
 930                                &style->new, style->newline,
 931                                plus_end - plus_begin, plus_begin,
 932                                line_prefix);
 933        }
 934
 935        diff_words->current_plus = plus_end;
 936        diff_words->last_minus = minus_first;
 937}
 938
 939/* This function starts looking at *begin, and returns 0 iff a word was found. */
 940static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 941                int *begin, int *end)
 942{
 943        if (word_regex && *begin < buffer->size) {
 944                regmatch_t match[1];
 945                if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 946                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 947                                        '\n', match[0].rm_eo - match[0].rm_so);
 948                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 949                        *begin += match[0].rm_so;
 950                        return *begin >= *end;
 951                }
 952                return -1;
 953        }
 954
 955        /* find the next word */
 956        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 957                (*begin)++;
 958        if (*begin >= buffer->size)
 959                return -1;
 960
 961        /* find the end of the word */
 962        *end = *begin + 1;
 963        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 964                (*end)++;
 965
 966        return 0;
 967}
 968
 969/*
 970 * This function splits the words in buffer->text, stores the list with
 971 * newline separator into out, and saves the offsets of the original words
 972 * in buffer->orig.
 973 */
 974static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 975                regex_t *word_regex)
 976{
 977        int i, j;
 978        long alloc = 0;
 979
 980        out->size = 0;
 981        out->ptr = NULL;
 982
 983        /* fake an empty "0th" word */
 984        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 985        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 986        buffer->orig_nr = 1;
 987
 988        for (i = 0; i < buffer->text.size; i++) {
 989                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 990                        return;
 991
 992                /* store original boundaries */
 993                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
 994                                buffer->orig_alloc);
 995                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
 996                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
 997                buffer->orig_nr++;
 998
 999                /* store one word */
1000                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
1001                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
1002                out->ptr[out->size + j - i] = '\n';
1003                out->size += j - i + 1;
1004
1005                i = j - 1;
1006        }
1007}
1008
1009/* this executes the word diff on the accumulated buffers */
1010static void diff_words_show(struct diff_words_data *diff_words)
1011{
1012        xpparam_t xpp;
1013        xdemitconf_t xecfg;
1014        mmfile_t minus, plus;
1015        struct diff_words_style *style = diff_words->style;
1016
1017        struct diff_options *opt = diff_words->opt;
1018        const char *line_prefix;
1019
1020        assert(opt);
1021        line_prefix = diff_line_prefix(opt);
1022
1023        /* special case: only removal */
1024        if (!diff_words->plus.text.size) {
1025                fputs(line_prefix, diff_words->opt->file);
1026                fn_out_diff_words_write_helper(diff_words->opt->file,
1027                        &style->old, style->newline,
1028                        diff_words->minus.text.size,
1029                        diff_words->minus.text.ptr, line_prefix);
1030                diff_words->minus.text.size = 0;
1031                return;
1032        }
1033
1034        diff_words->current_plus = diff_words->plus.text.ptr;
1035        diff_words->last_minus = 0;
1036
1037        memset(&xpp, 0, sizeof(xpp));
1038        memset(&xecfg, 0, sizeof(xecfg));
1039        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1040        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1041        xpp.flags = 0;
1042        /* as only the hunk header will be parsed, we need a 0-context */
1043        xecfg.ctxlen = 0;
1044        if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1045                          &xpp, &xecfg))
1046                die("unable to generate word diff");
1047        free(minus.ptr);
1048        free(plus.ptr);
1049        if (diff_words->current_plus != diff_words->plus.text.ptr +
1050                        diff_words->plus.text.size) {
1051                if (color_words_output_graph_prefix(diff_words))
1052                        fputs(line_prefix, diff_words->opt->file);
1053                fn_out_diff_words_write_helper(diff_words->opt->file,
1054                        &style->ctx, style->newline,
1055                        diff_words->plus.text.ptr + diff_words->plus.text.size
1056                        - diff_words->current_plus, diff_words->current_plus,
1057                        line_prefix);
1058        }
1059        diff_words->minus.text.size = diff_words->plus.text.size = 0;
1060}
1061
1062/* In "color-words" mode, show word-diff of words accumulated in the buffer */
1063static void diff_words_flush(struct emit_callback *ecbdata)
1064{
1065        if (ecbdata->diff_words->minus.text.size ||
1066            ecbdata->diff_words->plus.text.size)
1067                diff_words_show(ecbdata->diff_words);
1068}
1069
1070static void diff_filespec_load_driver(struct diff_filespec *one)
1071{
1072        /* Use already-loaded driver */
1073        if (one->driver)
1074                return;
1075
1076        if (S_ISREG(one->mode))
1077                one->driver = userdiff_find_by_path(one->path);
1078
1079        /* Fallback to default settings */
1080        if (!one->driver)
1081                one->driver = userdiff_find_by_name("default");
1082}
1083
1084static const char *userdiff_word_regex(struct diff_filespec *one)
1085{
1086        diff_filespec_load_driver(one);
1087        return one->driver->word_regex;
1088}
1089
1090static void init_diff_words_data(struct emit_callback *ecbdata,
1091                                 struct diff_options *orig_opts,
1092                                 struct diff_filespec *one,
1093                                 struct diff_filespec *two)
1094{
1095        int i;
1096        struct diff_options *o = xmalloc(sizeof(struct diff_options));
1097        memcpy(o, orig_opts, sizeof(struct diff_options));
1098
1099        ecbdata->diff_words =
1100                xcalloc(1, sizeof(struct diff_words_data));
1101        ecbdata->diff_words->type = o->word_diff;
1102        ecbdata->diff_words->opt = o;
1103        if (!o->word_regex)
1104                o->word_regex = userdiff_word_regex(one);
1105        if (!o->word_regex)
1106                o->word_regex = userdiff_word_regex(two);
1107        if (!o->word_regex)
1108                o->word_regex = diff_word_regex_cfg;
1109        if (o->word_regex) {
1110                ecbdata->diff_words->word_regex = (regex_t *)
1111                        xmalloc(sizeof(regex_t));
1112                if (regcomp(ecbdata->diff_words->word_regex,
1113                            o->word_regex,
1114                            REG_EXTENDED | REG_NEWLINE))
1115                        die ("Invalid regular expression: %s",
1116                             o->word_regex);
1117        }
1118        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1119                if (o->word_diff == diff_words_styles[i].type) {
1120                        ecbdata->diff_words->style =
1121                                &diff_words_styles[i];
1122                        break;
1123                }
1124        }
1125        if (want_color(o->use_color)) {
1126                struct diff_words_style *st = ecbdata->diff_words->style;
1127                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1128                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1129                st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1130        }
1131}
1132
1133static void free_diff_words_data(struct emit_callback *ecbdata)
1134{
1135        if (ecbdata->diff_words) {
1136                diff_words_flush(ecbdata);
1137                free (ecbdata->diff_words->opt);
1138                free (ecbdata->diff_words->minus.text.ptr);
1139                free (ecbdata->diff_words->minus.orig);
1140                free (ecbdata->diff_words->plus.text.ptr);
1141                free (ecbdata->diff_words->plus.orig);
1142                if (ecbdata->diff_words->word_regex) {
1143                        regfree(ecbdata->diff_words->word_regex);
1144                        free(ecbdata->diff_words->word_regex);
1145                }
1146                free(ecbdata->diff_words);
1147                ecbdata->diff_words = NULL;
1148        }
1149}
1150
1151const char *diff_get_color(int diff_use_color, enum color_diff ix)
1152{
1153        if (want_color(diff_use_color))
1154                return diff_colors[ix];
1155        return "";
1156}
1157
1158const char *diff_line_prefix(struct diff_options *opt)
1159{
1160        struct strbuf *msgbuf;
1161        if (!opt->output_prefix)
1162                return "";
1163
1164        msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1165        return msgbuf->buf;
1166}
1167
1168static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1169{
1170        const char *cp;
1171        unsigned long allot;
1172        size_t l = len;
1173
1174        if (ecb->truncate)
1175                return ecb->truncate(line, len);
1176        cp = line;
1177        allot = l;
1178        while (0 < l) {
1179                (void) utf8_width(&cp, &l);
1180                if (!cp)
1181                        break; /* truncated in the middle? */
1182        }
1183        return allot - l;
1184}
1185
1186static void find_lno(const char *line, struct emit_callback *ecbdata)
1187{
1188        const char *p;
1189        ecbdata->lno_in_preimage = 0;
1190        ecbdata->lno_in_postimage = 0;
1191        p = strchr(line, '-');
1192        if (!p)
1193                return; /* cannot happen */
1194        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1195        p = strchr(p, '+');
1196        if (!p)
1197                return; /* cannot happen */
1198        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1199}
1200
1201static void fn_out_consume(void *priv, char *line, unsigned long len)
1202{
1203        struct emit_callback *ecbdata = priv;
1204        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1205        const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1206        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1207        struct diff_options *o = ecbdata->opt;
1208        const char *line_prefix = diff_line_prefix(o);
1209
1210        if (ecbdata->header) {
1211                fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1212                strbuf_reset(ecbdata->header);
1213                ecbdata->header = NULL;
1214        }
1215        *(ecbdata->found_changesp) = 1;
1216
1217        if (ecbdata->label_path[0]) {
1218                const char *name_a_tab, *name_b_tab;
1219
1220                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1221                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1222
1223                fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1224                        line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1225                fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1226                        line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1227                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1228        }
1229
1230        if (diff_suppress_blank_empty
1231            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1232                line[0] = '\n';
1233                len = 1;
1234        }
1235
1236        if (line[0] == '@') {
1237                if (ecbdata->diff_words)
1238                        diff_words_flush(ecbdata);
1239                len = sane_truncate_line(ecbdata, line, len);
1240                find_lno(line, ecbdata);
1241                emit_hunk_header(ecbdata, line, len);
1242                if (line[len-1] != '\n')
1243                        putc('\n', ecbdata->opt->file);
1244                return;
1245        }
1246
1247        if (len < 1) {
1248                emit_line(ecbdata->opt, reset, reset, line, len);
1249                if (ecbdata->diff_words
1250                    && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1251                        fputs("~\n", ecbdata->opt->file);
1252                return;
1253        }
1254
1255        if (ecbdata->diff_words) {
1256                if (line[0] == '-') {
1257                        diff_words_append(line, len,
1258                                          &ecbdata->diff_words->minus);
1259                        return;
1260                } else if (line[0] == '+') {
1261                        diff_words_append(line, len,
1262                                          &ecbdata->diff_words->plus);
1263                        return;
1264                } else if (starts_with(line, "\\ ")) {
1265                        /*
1266                         * Eat the "no newline at eof" marker as if we
1267                         * saw a "+" or "-" line with nothing on it,
1268                         * and return without diff_words_flush() to
1269                         * defer processing. If this is the end of
1270                         * preimage, more "+" lines may come after it.
1271                         */
1272                        return;
1273                }
1274                diff_words_flush(ecbdata);
1275                if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1276                        emit_line(ecbdata->opt, context, reset, line, len);
1277                        fputs("~\n", ecbdata->opt->file);
1278                } else {
1279                        /*
1280                         * Skip the prefix character, if any.  With
1281                         * diff_suppress_blank_empty, there may be
1282                         * none.
1283                         */
1284                        if (line[0] != '\n') {
1285                              line++;
1286                              len--;
1287                        }
1288                        emit_line(ecbdata->opt, context, reset, line, len);
1289                }
1290                return;
1291        }
1292
1293        switch (line[0]) {
1294        case '+':
1295                ecbdata->lno_in_postimage++;
1296                emit_add_line(reset, ecbdata, line + 1, len - 1);
1297                break;
1298        case '-':
1299                ecbdata->lno_in_preimage++;
1300                emit_del_line(reset, ecbdata, line + 1, len - 1);
1301                break;
1302        case ' ':
1303                ecbdata->lno_in_postimage++;
1304                ecbdata->lno_in_preimage++;
1305                emit_context_line(reset, ecbdata, line + 1, len - 1);
1306                break;
1307        default:
1308                /* incomplete line at the end */
1309                ecbdata->lno_in_preimage++;
1310                emit_line(ecbdata->opt,
1311                          diff_get_color(ecbdata->color_diff, DIFF_CONTEXT),
1312                          reset, line, len);
1313                break;
1314        }
1315}
1316
1317static char *pprint_rename(const char *a, const char *b)
1318{
1319        const char *old = a;
1320        const char *new = b;
1321        struct strbuf name = STRBUF_INIT;
1322        int pfx_length, sfx_length;
1323        int pfx_adjust_for_slash;
1324        int len_a = strlen(a);
1325        int len_b = strlen(b);
1326        int a_midlen, b_midlen;
1327        int qlen_a = quote_c_style(a, NULL, NULL, 0);
1328        int qlen_b = quote_c_style(b, NULL, NULL, 0);
1329
1330        if (qlen_a || qlen_b) {
1331                quote_c_style(a, &name, NULL, 0);
1332                strbuf_addstr(&name, " => ");
1333                quote_c_style(b, &name, NULL, 0);
1334                return strbuf_detach(&name, NULL);
1335        }
1336
1337        /* Find common prefix */
1338        pfx_length = 0;
1339        while (*old && *new && *old == *new) {
1340                if (*old == '/')
1341                        pfx_length = old - a + 1;
1342                old++;
1343                new++;
1344        }
1345
1346        /* Find common suffix */
1347        old = a + len_a;
1348        new = b + len_b;
1349        sfx_length = 0;
1350        /*
1351         * If there is a common prefix, it must end in a slash.  In
1352         * that case we let this loop run 1 into the prefix to see the
1353         * same slash.
1354         *
1355         * If there is no common prefix, we cannot do this as it would
1356         * underrun the input strings.
1357         */
1358        pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1359        while (a + pfx_length - pfx_adjust_for_slash <= old &&
1360               b + pfx_length - pfx_adjust_for_slash <= new &&
1361               *old == *new) {
1362                if (*old == '/')
1363                        sfx_length = len_a - (old - a);
1364                old--;
1365                new--;
1366        }
1367
1368        /*
1369         * pfx{mid-a => mid-b}sfx
1370         * {pfx-a => pfx-b}sfx
1371         * pfx{sfx-a => sfx-b}
1372         * name-a => name-b
1373         */
1374        a_midlen = len_a - pfx_length - sfx_length;
1375        b_midlen = len_b - pfx_length - sfx_length;
1376        if (a_midlen < 0)
1377                a_midlen = 0;
1378        if (b_midlen < 0)
1379                b_midlen = 0;
1380
1381        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1382        if (pfx_length + sfx_length) {
1383                strbuf_add(&name, a, pfx_length);
1384                strbuf_addch(&name, '{');
1385        }
1386        strbuf_add(&name, a + pfx_length, a_midlen);
1387        strbuf_addstr(&name, " => ");
1388        strbuf_add(&name, b + pfx_length, b_midlen);
1389        if (pfx_length + sfx_length) {
1390                strbuf_addch(&name, '}');
1391                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1392        }
1393        return strbuf_detach(&name, NULL);
1394}
1395
1396struct diffstat_t {
1397        int nr;
1398        int alloc;
1399        struct diffstat_file {
1400                char *from_name;
1401                char *name;
1402                char *print_name;
1403                unsigned is_unmerged:1;
1404                unsigned is_binary:1;
1405                unsigned is_renamed:1;
1406                unsigned is_interesting:1;
1407                uintmax_t added, deleted;
1408        } **files;
1409};
1410
1411static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1412                                          const char *name_a,
1413                                          const char *name_b)
1414{
1415        struct diffstat_file *x;
1416        x = xcalloc(1, sizeof(*x));
1417        ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
1418        diffstat->files[diffstat->nr++] = x;
1419        if (name_b) {
1420                x->from_name = xstrdup(name_a);
1421                x->name = xstrdup(name_b);
1422                x->is_renamed = 1;
1423        }
1424        else {
1425                x->from_name = NULL;
1426                x->name = xstrdup(name_a);
1427        }
1428        return x;
1429}
1430
1431static void diffstat_consume(void *priv, char *line, unsigned long len)
1432{
1433        struct diffstat_t *diffstat = priv;
1434        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1435
1436        if (line[0] == '+')
1437                x->added++;
1438        else if (line[0] == '-')
1439                x->deleted++;
1440}
1441
1442const char mime_boundary_leader[] = "------------";
1443
1444static int scale_linear(int it, int width, int max_change)
1445{
1446        if (!it)
1447                return 0;
1448        /*
1449         * make sure that at least one '-' or '+' is printed if
1450         * there is any change to this path. The easiest way is to
1451         * scale linearly as if the alloted width is one column shorter
1452         * than it is, and then add 1 to the result.
1453         */
1454        return 1 + (it * (width - 1) / max_change);
1455}
1456
1457static void show_name(FILE *file,
1458                      const char *prefix, const char *name, int len)
1459{
1460        fprintf(file, " %s%-*s |", prefix, len, name);
1461}
1462
1463static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1464{
1465        if (cnt <= 0)
1466                return;
1467        fprintf(file, "%s", set);
1468        while (cnt--)
1469                putc(ch, file);
1470        fprintf(file, "%s", reset);
1471}
1472
1473static void fill_print_name(struct diffstat_file *file)
1474{
1475        char *pname;
1476
1477        if (file->print_name)
1478                return;
1479
1480        if (!file->is_renamed) {
1481                struct strbuf buf = STRBUF_INIT;
1482                if (quote_c_style(file->name, &buf, NULL, 0)) {
1483                        pname = strbuf_detach(&buf, NULL);
1484                } else {
1485                        pname = file->name;
1486                        strbuf_release(&buf);
1487                }
1488        } else {
1489                pname = pprint_rename(file->from_name, file->name);
1490        }
1491        file->print_name = pname;
1492}
1493
1494int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1495{
1496        struct strbuf sb = STRBUF_INIT;
1497        int ret;
1498
1499        if (!files) {
1500                assert(insertions == 0 && deletions == 0);
1501                return fprintf(fp, "%s\n", " 0 files changed");
1502        }
1503
1504        strbuf_addf(&sb,
1505                    (files == 1) ? " %d file changed" : " %d files changed",
1506                    files);
1507
1508        /*
1509         * For binary diff, the caller may want to print "x files
1510         * changed" with insertions == 0 && deletions == 0.
1511         *
1512         * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1513         * is probably less confusing (i.e skip over "2 files changed
1514         * but nothing about added/removed lines? Is this a bug in Git?").
1515         */
1516        if (insertions || deletions == 0) {
1517                strbuf_addf(&sb,
1518                            (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1519                            insertions);
1520        }
1521
1522        if (deletions || insertions == 0) {
1523                strbuf_addf(&sb,
1524                            (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1525                            deletions);
1526        }
1527        strbuf_addch(&sb, '\n');
1528        ret = fputs(sb.buf, fp);
1529        strbuf_release(&sb);
1530        return ret;
1531}
1532
1533static void show_stats(struct diffstat_t *data, struct diff_options *options)
1534{
1535        int i, len, add, del, adds = 0, dels = 0;
1536        uintmax_t max_change = 0, max_len = 0;
1537        int total_files = data->nr, count;
1538        int width, name_width, graph_width, number_width = 0, bin_width = 0;
1539        const char *reset, *add_c, *del_c;
1540        const char *line_prefix = "";
1541        int extra_shown = 0;
1542
1543        if (data->nr == 0)
1544                return;
1545
1546        line_prefix = diff_line_prefix(options);
1547        count = options->stat_count ? options->stat_count : data->nr;
1548
1549        reset = diff_get_color_opt(options, DIFF_RESET);
1550        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1551        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1552
1553        /*
1554         * Find the longest filename and max number of changes
1555         */
1556        for (i = 0; (i < count) && (i < data->nr); i++) {
1557                struct diffstat_file *file = data->files[i];
1558                uintmax_t change = file->added + file->deleted;
1559
1560                if (!file->is_interesting && (change == 0)) {
1561                        count++; /* not shown == room for one more */
1562                        continue;
1563                }
1564                fill_print_name(file);
1565                len = strlen(file->print_name);
1566                if (max_len < len)
1567                        max_len = len;
1568
1569                if (file->is_unmerged) {
1570                        /* "Unmerged" is 8 characters */
1571                        bin_width = bin_width < 8 ? 8 : bin_width;
1572                        continue;
1573                }
1574                if (file->is_binary) {
1575                        /* "Bin XXX -> YYY bytes" */
1576                        int w = 14 + decimal_width(file->added)
1577                                + decimal_width(file->deleted);
1578                        bin_width = bin_width < w ? w : bin_width;
1579                        /* Display change counts aligned with "Bin" */
1580                        number_width = 3;
1581                        continue;
1582                }
1583
1584                if (max_change < change)
1585                        max_change = change;
1586        }
1587        count = i; /* where we can stop scanning in data->files[] */
1588
1589        /*
1590         * We have width = stat_width or term_columns() columns total.
1591         * We want a maximum of min(max_len, stat_name_width) for the name part.
1592         * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1593         * We also need 1 for " " and 4 + decimal_width(max_change)
1594         * for " | NNNN " and one the empty column at the end, altogether
1595         * 6 + decimal_width(max_change).
1596         *
1597         * If there's not enough space, we will use the smaller of
1598         * stat_name_width (if set) and 5/8*width for the filename,
1599         * and the rest for constant elements + graph part, but no more
1600         * than stat_graph_width for the graph part.
1601         * (5/8 gives 50 for filename and 30 for the constant parts + graph
1602         * for the standard terminal size).
1603         *
1604         * In other words: stat_width limits the maximum width, and
1605         * stat_name_width fixes the maximum width of the filename,
1606         * and is also used to divide available columns if there
1607         * aren't enough.
1608         *
1609         * Binary files are displayed with "Bin XXX -> YYY bytes"
1610         * instead of the change count and graph. This part is treated
1611         * similarly to the graph part, except that it is not
1612         * "scaled". If total width is too small to accommodate the
1613         * guaranteed minimum width of the filename part and the
1614         * separators and this message, this message will "overflow"
1615         * making the line longer than the maximum width.
1616         */
1617
1618        if (options->stat_width == -1)
1619                width = term_columns() - options->output_prefix_length;
1620        else
1621                width = options->stat_width ? options->stat_width : 80;
1622        number_width = decimal_width(max_change) > number_width ?
1623                decimal_width(max_change) : number_width;
1624
1625        if (options->stat_graph_width == -1)
1626                options->stat_graph_width = diff_stat_graph_width;
1627
1628        /*
1629         * Guarantee 3/8*16==6 for the graph part
1630         * and 5/8*16==10 for the filename part
1631         */
1632        if (width < 16 + 6 + number_width)
1633                width = 16 + 6 + number_width;
1634
1635        /*
1636         * First assign sizes that are wanted, ignoring available width.
1637         * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1638         * starting from "XXX" should fit in graph_width.
1639         */
1640        graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1641        if (options->stat_graph_width &&
1642            options->stat_graph_width < graph_width)
1643                graph_width = options->stat_graph_width;
1644
1645        name_width = (options->stat_name_width > 0 &&
1646                      options->stat_name_width < max_len) ?
1647                options->stat_name_width : max_len;
1648
1649        /*
1650         * Adjust adjustable widths not to exceed maximum width
1651         */
1652        if (name_width + number_width + 6 + graph_width > width) {
1653                if (graph_width > width * 3/8 - number_width - 6) {
1654                        graph_width = width * 3/8 - number_width - 6;
1655                        if (graph_width < 6)
1656                                graph_width = 6;
1657                }
1658
1659                if (options->stat_graph_width &&
1660                    graph_width > options->stat_graph_width)
1661                        graph_width = options->stat_graph_width;
1662                if (name_width > width - number_width - 6 - graph_width)
1663                        name_width = width - number_width - 6 - graph_width;
1664                else
1665                        graph_width = width - number_width - 6 - name_width;
1666        }
1667
1668        /*
1669         * From here name_width is the width of the name area,
1670         * and graph_width is the width of the graph area.
1671         * max_change is used to scale graph properly.
1672         */
1673        for (i = 0; i < count; i++) {
1674                const char *prefix = "";
1675                struct diffstat_file *file = data->files[i];
1676                char *name = file->print_name;
1677                uintmax_t added = file->added;
1678                uintmax_t deleted = file->deleted;
1679                int name_len;
1680
1681                if (!file->is_interesting && (added + deleted == 0))
1682                        continue;
1683
1684                /*
1685                 * "scale" the filename
1686                 */
1687                len = name_width;
1688                name_len = strlen(name);
1689                if (name_width < name_len) {
1690                        char *slash;
1691                        prefix = "...";
1692                        len -= 3;
1693                        name += name_len - len;
1694                        slash = strchr(name, '/');
1695                        if (slash)
1696                                name = slash;
1697                }
1698
1699                if (file->is_binary) {
1700                        fprintf(options->file, "%s", line_prefix);
1701                        show_name(options->file, prefix, name, len);
1702                        fprintf(options->file, " %*s", number_width, "Bin");
1703                        if (!added && !deleted) {
1704                                putc('\n', options->file);
1705                                continue;
1706                        }
1707                        fprintf(options->file, " %s%"PRIuMAX"%s",
1708                                del_c, deleted, reset);
1709                        fprintf(options->file, " -> ");
1710                        fprintf(options->file, "%s%"PRIuMAX"%s",
1711                                add_c, added, reset);
1712                        fprintf(options->file, " bytes");
1713                        fprintf(options->file, "\n");
1714                        continue;
1715                }
1716                else if (file->is_unmerged) {
1717                        fprintf(options->file, "%s", line_prefix);
1718                        show_name(options->file, prefix, name, len);
1719                        fprintf(options->file, " Unmerged\n");
1720                        continue;
1721                }
1722
1723                /*
1724                 * scale the add/delete
1725                 */
1726                add = added;
1727                del = deleted;
1728
1729                if (graph_width <= max_change) {
1730                        int total = scale_linear(add + del, graph_width, max_change);
1731                        if (total < 2 && add && del)
1732                                /* width >= 2 due to the sanity check */
1733                                total = 2;
1734                        if (add < del) {
1735                                add = scale_linear(add, graph_width, max_change);
1736                                del = total - add;
1737                        } else {
1738                                del = scale_linear(del, graph_width, max_change);
1739                                add = total - del;
1740                        }
1741                }
1742                fprintf(options->file, "%s", line_prefix);
1743                show_name(options->file, prefix, name, len);
1744                fprintf(options->file, " %*"PRIuMAX"%s",
1745                        number_width, added + deleted,
1746                        added + deleted ? " " : "");
1747                show_graph(options->file, '+', add, add_c, reset);
1748                show_graph(options->file, '-', del, del_c, reset);
1749                fprintf(options->file, "\n");
1750        }
1751
1752        for (i = 0; i < data->nr; i++) {
1753                struct diffstat_file *file = data->files[i];
1754                uintmax_t added = file->added;
1755                uintmax_t deleted = file->deleted;
1756
1757                if (file->is_unmerged ||
1758                    (!file->is_interesting && (added + deleted == 0))) {
1759                        total_files--;
1760                        continue;
1761                }
1762
1763                if (!file->is_binary) {
1764                        adds += added;
1765                        dels += deleted;
1766                }
1767                if (i < count)
1768                        continue;
1769                if (!extra_shown)
1770                        fprintf(options->file, "%s ...\n", line_prefix);
1771                extra_shown = 1;
1772        }
1773        fprintf(options->file, "%s", line_prefix);
1774        print_stat_summary(options->file, total_files, adds, dels);
1775}
1776
1777static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1778{
1779        int i, adds = 0, dels = 0, total_files = data->nr;
1780
1781        if (data->nr == 0)
1782                return;
1783
1784        for (i = 0; i < data->nr; i++) {
1785                int added = data->files[i]->added;
1786                int deleted= data->files[i]->deleted;
1787
1788                if (data->files[i]->is_unmerged ||
1789                    (!data->files[i]->is_interesting && (added + deleted == 0))) {
1790                        total_files--;
1791                } else if (!data->files[i]->is_binary) { /* don't count bytes */
1792                        adds += added;
1793                        dels += deleted;
1794                }
1795        }
1796        fprintf(options->file, "%s", diff_line_prefix(options));
1797        print_stat_summary(options->file, total_files, adds, dels);
1798}
1799
1800static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1801{
1802        int i;
1803
1804        if (data->nr == 0)
1805                return;
1806
1807        for (i = 0; i < data->nr; i++) {
1808                struct diffstat_file *file = data->files[i];
1809
1810                fprintf(options->file, "%s", diff_line_prefix(options));
1811
1812                if (file->is_binary)
1813                        fprintf(options->file, "-\t-\t");
1814                else
1815                        fprintf(options->file,
1816                                "%"PRIuMAX"\t%"PRIuMAX"\t",
1817                                file->added, file->deleted);
1818                if (options->line_termination) {
1819                        fill_print_name(file);
1820                        if (!file->is_renamed)
1821                                write_name_quoted(file->name, options->file,
1822                                                  options->line_termination);
1823                        else {
1824                                fputs(file->print_name, options->file);
1825                                putc(options->line_termination, options->file);
1826                        }
1827                } else {
1828                        if (file->is_renamed) {
1829                                putc('\0', options->file);
1830                                write_name_quoted(file->from_name, options->file, '\0');
1831                        }
1832                        write_name_quoted(file->name, options->file, '\0');
1833                }
1834        }
1835}
1836
1837struct dirstat_file {
1838        const char *name;
1839        unsigned long changed;
1840};
1841
1842struct dirstat_dir {
1843        struct dirstat_file *files;
1844        int alloc, nr, permille, cumulative;
1845};
1846
1847static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1848                unsigned long changed, const char *base, int baselen)
1849{
1850        unsigned long this_dir = 0;
1851        unsigned int sources = 0;
1852        const char *line_prefix = diff_line_prefix(opt);
1853
1854        while (dir->nr) {
1855                struct dirstat_file *f = dir->files;
1856                int namelen = strlen(f->name);
1857                unsigned long this;
1858                char *slash;
1859
1860                if (namelen < baselen)
1861                        break;
1862                if (memcmp(f->name, base, baselen))
1863                        break;
1864                slash = strchr(f->name + baselen, '/');
1865                if (slash) {
1866                        int newbaselen = slash + 1 - f->name;
1867                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1868                        sources++;
1869                } else {
1870                        this = f->changed;
1871                        dir->files++;
1872                        dir->nr--;
1873                        sources += 2;
1874                }
1875                this_dir += this;
1876        }
1877
1878        /*
1879         * We don't report dirstat's for
1880         *  - the top level
1881         *  - or cases where everything came from a single directory
1882         *    under this directory (sources == 1).
1883         */
1884        if (baselen && sources != 1) {
1885                if (this_dir) {
1886                        int permille = this_dir * 1000 / changed;
1887                        if (permille >= dir->permille) {
1888                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1889                                        permille / 10, permille % 10, baselen, base);
1890                                if (!dir->cumulative)
1891                                        return 0;
1892                        }
1893                }
1894        }
1895        return this_dir;
1896}
1897
1898static int dirstat_compare(const void *_a, const void *_b)
1899{
1900        const struct dirstat_file *a = _a;
1901        const struct dirstat_file *b = _b;
1902        return strcmp(a->name, b->name);
1903}
1904
1905static void show_dirstat(struct diff_options *options)
1906{
1907        int i;
1908        unsigned long changed;
1909        struct dirstat_dir dir;
1910        struct diff_queue_struct *q = &diff_queued_diff;
1911
1912        dir.files = NULL;
1913        dir.alloc = 0;
1914        dir.nr = 0;
1915        dir.permille = options->dirstat_permille;
1916        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1917
1918        changed = 0;
1919        for (i = 0; i < q->nr; i++) {
1920                struct diff_filepair *p = q->queue[i];
1921                const char *name;
1922                unsigned long copied, added, damage;
1923                int content_changed;
1924
1925                name = p->two->path ? p->two->path : p->one->path;
1926
1927                if (p->one->sha1_valid && p->two->sha1_valid)
1928                        content_changed = hashcmp(p->one->sha1, p->two->sha1);
1929                else
1930                        content_changed = 1;
1931
1932                if (!content_changed) {
1933                        /*
1934                         * The SHA1 has not changed, so pre-/post-content is
1935                         * identical. We can therefore skip looking at the
1936                         * file contents altogether.
1937                         */
1938                        damage = 0;
1939                        goto found_damage;
1940                }
1941
1942                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1943                        /*
1944                         * In --dirstat-by-file mode, we don't really need to
1945                         * look at the actual file contents at all.
1946                         * The fact that the SHA1 changed is enough for us to
1947                         * add this file to the list of results
1948                         * (with each file contributing equal damage).
1949                         */
1950                        damage = 1;
1951                        goto found_damage;
1952                }
1953
1954                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1955                        diff_populate_filespec(p->one, 0);
1956                        diff_populate_filespec(p->two, 0);
1957                        diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1958                                               &copied, &added);
1959                        diff_free_filespec_data(p->one);
1960                        diff_free_filespec_data(p->two);
1961                } else if (DIFF_FILE_VALID(p->one)) {
1962                        diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
1963                        copied = added = 0;
1964                        diff_free_filespec_data(p->one);
1965                } else if (DIFF_FILE_VALID(p->two)) {
1966                        diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
1967                        copied = 0;
1968                        added = p->two->size;
1969                        diff_free_filespec_data(p->two);
1970                } else
1971                        continue;
1972
1973                /*
1974                 * Original minus copied is the removed material,
1975                 * added is the new material.  They are both damages
1976                 * made to the preimage.
1977                 * If the resulting damage is zero, we know that
1978                 * diffcore_count_changes() considers the two entries to
1979                 * be identical, but since content_changed is true, we
1980                 * know that there must have been _some_ kind of change,
1981                 * so we force all entries to have damage > 0.
1982                 */
1983                damage = (p->one->size - copied) + added;
1984                if (!damage)
1985                        damage = 1;
1986
1987found_damage:
1988                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1989                dir.files[dir.nr].name = name;
1990                dir.files[dir.nr].changed = damage;
1991                changed += damage;
1992                dir.nr++;
1993        }
1994
1995        /* This can happen even with many files, if everything was renames */
1996        if (!changed)
1997                return;
1998
1999        /* Show all directories with more than x% of the changes */
2000        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
2001        gather_dirstat(options, &dir, changed, "", 0);
2002}
2003
2004static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
2005{
2006        int i;
2007        unsigned long changed;
2008        struct dirstat_dir dir;
2009
2010        if (data->nr == 0)
2011                return;
2012
2013        dir.files = NULL;
2014        dir.alloc = 0;
2015        dir.nr = 0;
2016        dir.permille = options->dirstat_permille;
2017        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2018
2019        changed = 0;
2020        for (i = 0; i < data->nr; i++) {
2021                struct diffstat_file *file = data->files[i];
2022                unsigned long damage = file->added + file->deleted;
2023                if (file->is_binary)
2024                        /*
2025                         * binary files counts bytes, not lines. Must find some
2026                         * way to normalize binary bytes vs. textual lines.
2027                         * The following heuristic assumes that there are 64
2028                         * bytes per "line".
2029                         * This is stupid and ugly, but very cheap...
2030                         */
2031                        damage = (damage + 63) / 64;
2032                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2033                dir.files[dir.nr].name = file->name;
2034                dir.files[dir.nr].changed = damage;
2035                changed += damage;
2036                dir.nr++;
2037        }
2038
2039        /* This can happen even with many files, if everything was renames */
2040        if (!changed)
2041                return;
2042
2043        /* Show all directories with more than x% of the changes */
2044        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
2045        gather_dirstat(options, &dir, changed, "", 0);
2046}
2047
2048static void free_diffstat_info(struct diffstat_t *diffstat)
2049{
2050        int i;
2051        for (i = 0; i < diffstat->nr; i++) {
2052                struct diffstat_file *f = diffstat->files[i];
2053                if (f->name != f->print_name)
2054                        free(f->print_name);
2055                free(f->name);
2056                free(f->from_name);
2057                free(f);
2058        }
2059        free(diffstat->files);
2060}
2061
2062struct checkdiff_t {
2063        const char *filename;
2064        int lineno;
2065        int conflict_marker_size;
2066        struct diff_options *o;
2067        unsigned ws_rule;
2068        unsigned status;
2069};
2070
2071static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2072{
2073        char firstchar;
2074        int cnt;
2075
2076        if (len < marker_size + 1)
2077                return 0;
2078        firstchar = line[0];
2079        switch (firstchar) {
2080        case '=': case '>': case '<': case '|':
2081                break;
2082        default:
2083                return 0;
2084        }
2085        for (cnt = 1; cnt < marker_size; cnt++)
2086                if (line[cnt] != firstchar)
2087                        return 0;
2088        /* line[1] thru line[marker_size-1] are same as firstchar */
2089        if (len < marker_size + 1 || !isspace(line[marker_size]))
2090                return 0;
2091        return 1;
2092}
2093
2094static void checkdiff_consume(void *priv, char *line, unsigned long len)
2095{
2096        struct checkdiff_t *data = priv;
2097        int marker_size = data->conflict_marker_size;
2098        const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2099        const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2100        const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2101        char *err;
2102        const char *line_prefix;
2103
2104        assert(data->o);
2105        line_prefix = diff_line_prefix(data->o);
2106
2107        if (line[0] == '+') {
2108                unsigned bad;
2109                data->lineno++;
2110                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2111                        data->status |= 1;
2112                        fprintf(data->o->file,
2113                                "%s%s:%d: leftover conflict marker\n",
2114                                line_prefix, data->filename, data->lineno);
2115                }
2116                bad = ws_check(line + 1, len - 1, data->ws_rule);
2117                if (!bad)
2118                        return;
2119                data->status |= bad;
2120                err = whitespace_error_string(bad);
2121                fprintf(data->o->file, "%s%s:%d: %s.\n",
2122                        line_prefix, data->filename, data->lineno, err);
2123                free(err);
2124                emit_line(data->o, set, reset, line, 1);
2125                ws_check_emit(line + 1, len - 1, data->ws_rule,
2126                              data->o->file, set, reset, ws);
2127        } else if (line[0] == ' ') {
2128                data->lineno++;
2129        } else if (line[0] == '@') {
2130                char *plus = strchr(line, '+');
2131                if (plus)
2132                        data->lineno = strtol(plus, NULL, 10) - 1;
2133                else
2134                        die("invalid diff");
2135        }
2136}
2137
2138static unsigned char *deflate_it(char *data,
2139                                 unsigned long size,
2140                                 unsigned long *result_size)
2141{
2142        int bound;
2143        unsigned char *deflated;
2144        git_zstream stream;
2145
2146        git_deflate_init(&stream, zlib_compression_level);
2147        bound = git_deflate_bound(&stream, size);
2148        deflated = xmalloc(bound);
2149        stream.next_out = deflated;
2150        stream.avail_out = bound;
2151
2152        stream.next_in = (unsigned char *)data;
2153        stream.avail_in = size;
2154        while (git_deflate(&stream, Z_FINISH) == Z_OK)
2155                ; /* nothing */
2156        git_deflate_end(&stream);
2157        *result_size = stream.total_out;
2158        return deflated;
2159}
2160
2161static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2162                                  const char *prefix)
2163{
2164        void *cp;
2165        void *delta;
2166        void *deflated;
2167        void *data;
2168        unsigned long orig_size;
2169        unsigned long delta_size;
2170        unsigned long deflate_size;
2171        unsigned long data_size;
2172
2173        /* We could do deflated delta, or we could do just deflated two,
2174         * whichever is smaller.
2175         */
2176        delta = NULL;
2177        deflated = deflate_it(two->ptr, two->size, &deflate_size);
2178        if (one->size && two->size) {
2179                delta = diff_delta(one->ptr, one->size,
2180                                   two->ptr, two->size,
2181                                   &delta_size, deflate_size);
2182                if (delta) {
2183                        void *to_free = delta;
2184                        orig_size = delta_size;
2185                        delta = deflate_it(delta, delta_size, &delta_size);
2186                        free(to_free);
2187                }
2188        }
2189
2190        if (delta && delta_size < deflate_size) {
2191                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2192                free(deflated);
2193                data = delta;
2194                data_size = delta_size;
2195        }
2196        else {
2197                fprintf(file, "%sliteral %lu\n", prefix, two->size);
2198                free(delta);
2199                data = deflated;
2200                data_size = deflate_size;
2201        }
2202
2203        /* emit data encoded in base85 */
2204        cp = data;
2205        while (data_size) {
2206                int bytes = (52 < data_size) ? 52 : data_size;
2207                char line[70];
2208                data_size -= bytes;
2209                if (bytes <= 26)
2210                        line[0] = bytes + 'A' - 1;
2211                else
2212                        line[0] = bytes - 26 + 'a' - 1;
2213                encode_85(line + 1, cp, bytes);
2214                cp = (char *) cp + bytes;
2215                fprintf(file, "%s", prefix);
2216                fputs(line, file);
2217                fputc('\n', file);
2218        }
2219        fprintf(file, "%s\n", prefix);
2220        free(data);
2221}
2222
2223static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2224                             const char *prefix)
2225{
2226        fprintf(file, "%sGIT binary patch\n", prefix);
2227        emit_binary_diff_body(file, one, two, prefix);
2228        emit_binary_diff_body(file, two, one, prefix);
2229}
2230
2231int diff_filespec_is_binary(struct diff_filespec *one)
2232{
2233        if (one->is_binary == -1) {
2234                diff_filespec_load_driver(one);
2235                if (one->driver->binary != -1)
2236                        one->is_binary = one->driver->binary;
2237                else {
2238                        if (!one->data && DIFF_FILE_VALID(one))
2239                                diff_populate_filespec(one, CHECK_BINARY);
2240                        if (one->is_binary == -1 && one->data)
2241                                one->is_binary = buffer_is_binary(one->data,
2242                                                one->size);
2243                        if (one->is_binary == -1)
2244                                one->is_binary = 0;
2245                }
2246        }
2247        return one->is_binary;
2248}
2249
2250static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2251{
2252        diff_filespec_load_driver(one);
2253        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2254}
2255
2256void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2257{
2258        if (!options->a_prefix)
2259                options->a_prefix = a;
2260        if (!options->b_prefix)
2261                options->b_prefix = b;
2262}
2263
2264struct userdiff_driver *get_textconv(struct diff_filespec *one)
2265{
2266        if (!DIFF_FILE_VALID(one))
2267                return NULL;
2268
2269        diff_filespec_load_driver(one);
2270        return userdiff_get_textconv(one->driver);
2271}
2272
2273static void builtin_diff(const char *name_a,
2274                         const char *name_b,
2275                         struct diff_filespec *one,
2276                         struct diff_filespec *two,
2277                         const char *xfrm_msg,
2278                         int must_show_header,
2279                         struct diff_options *o,
2280                         int complete_rewrite)
2281{
2282        mmfile_t mf1, mf2;
2283        const char *lbl[2];
2284        char *a_one, *b_two;
2285        const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2286        const char *reset = diff_get_color_opt(o, DIFF_RESET);
2287        const char *a_prefix, *b_prefix;
2288        struct userdiff_driver *textconv_one = NULL;
2289        struct userdiff_driver *textconv_two = NULL;
2290        struct strbuf header = STRBUF_INIT;
2291        const char *line_prefix = diff_line_prefix(o);
2292
2293        if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2294                        (!one->mode || S_ISGITLINK(one->mode)) &&
2295                        (!two->mode || S_ISGITLINK(two->mode))) {
2296                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2297                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2298                show_submodule_summary(o->file, one->path ? one->path : two->path,
2299                                line_prefix,
2300                                one->sha1, two->sha1, two->dirty_submodule,
2301                                meta, del, add, reset);
2302                return;
2303        }
2304
2305        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2306                textconv_one = get_textconv(one);
2307                textconv_two = get_textconv(two);
2308        }
2309
2310        diff_set_mnemonic_prefix(o, "a/", "b/");
2311        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2312                a_prefix = o->b_prefix;
2313                b_prefix = o->a_prefix;
2314        } else {
2315                a_prefix = o->a_prefix;
2316                b_prefix = o->b_prefix;
2317        }
2318
2319        /* Never use a non-valid filename anywhere if at all possible */
2320        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2321        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2322
2323        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2324        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2325        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2326        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2327        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2328        if (lbl[0][0] == '/') {
2329                /* /dev/null */
2330                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2331                if (xfrm_msg)
2332                        strbuf_addstr(&header, xfrm_msg);
2333                must_show_header = 1;
2334        }
2335        else if (lbl[1][0] == '/') {
2336                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2337                if (xfrm_msg)
2338                        strbuf_addstr(&header, xfrm_msg);
2339                must_show_header = 1;
2340        }
2341        else {
2342                if (one->mode != two->mode) {
2343                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2344                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2345                        must_show_header = 1;
2346                }
2347                if (xfrm_msg)
2348                        strbuf_addstr(&header, xfrm_msg);
2349
2350                /*
2351                 * we do not run diff between different kind
2352                 * of objects.
2353                 */
2354                if ((one->mode ^ two->mode) & S_IFMT)
2355                        goto free_ab_and_return;
2356                if (complete_rewrite &&
2357                    (textconv_one || !diff_filespec_is_binary(one)) &&
2358                    (textconv_two || !diff_filespec_is_binary(two))) {
2359                        fprintf(o->file, "%s", header.buf);
2360                        strbuf_reset(&header);
2361                        emit_rewrite_diff(name_a, name_b, one, two,
2362                                                textconv_one, textconv_two, o);
2363                        o->found_changes = 1;
2364                        goto free_ab_and_return;
2365                }
2366        }
2367
2368        if (o->irreversible_delete && lbl[1][0] == '/') {
2369                fprintf(o->file, "%s", header.buf);
2370                strbuf_reset(&header);
2371                goto free_ab_and_return;
2372        } else if (!DIFF_OPT_TST(o, TEXT) &&
2373            ( (!textconv_one && diff_filespec_is_binary(one)) ||
2374              (!textconv_two && diff_filespec_is_binary(two)) )) {
2375                if (!one->data && !two->data &&
2376                    S_ISREG(one->mode) && S_ISREG(two->mode) &&
2377                    !DIFF_OPT_TST(o, BINARY)) {
2378                        if (!hashcmp(one->sha1, two->sha1)) {
2379                                if (must_show_header)
2380                                        fprintf(o->file, "%s", header.buf);
2381                                goto free_ab_and_return;
2382                        }
2383                        fprintf(o->file, "%s", header.buf);
2384                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2385                                line_prefix, lbl[0], lbl[1]);
2386                        goto free_ab_and_return;
2387                }
2388                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2389                        die("unable to read files to diff");
2390                /* Quite common confusing case */
2391                if (mf1.size == mf2.size &&
2392                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2393                        if (must_show_header)
2394                                fprintf(o->file, "%s", header.buf);
2395                        goto free_ab_and_return;
2396                }
2397                fprintf(o->file, "%s", header.buf);
2398                strbuf_reset(&header);
2399                if (DIFF_OPT_TST(o, BINARY))
2400                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2401                else
2402                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2403                                line_prefix, lbl[0], lbl[1]);
2404                o->found_changes = 1;
2405        } else {
2406                /* Crazy xdl interfaces.. */
2407                const char *diffopts = getenv("GIT_DIFF_OPTS");
2408                const char *v;
2409                xpparam_t xpp;
2410                xdemitconf_t xecfg;
2411                struct emit_callback ecbdata;
2412                const struct userdiff_funcname *pe;
2413
2414                if (must_show_header) {
2415                        fprintf(o->file, "%s", header.buf);
2416                        strbuf_reset(&header);
2417                }
2418
2419                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2420                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2421
2422                pe = diff_funcname_pattern(one);
2423                if (!pe)
2424                        pe = diff_funcname_pattern(two);
2425
2426                memset(&xpp, 0, sizeof(xpp));
2427                memset(&xecfg, 0, sizeof(xecfg));
2428                memset(&ecbdata, 0, sizeof(ecbdata));
2429                ecbdata.label_path = lbl;
2430                ecbdata.color_diff = want_color(o->use_color);
2431                ecbdata.found_changesp = &o->found_changes;
2432                ecbdata.ws_rule = whitespace_rule(name_b);
2433                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2434                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2435                ecbdata.opt = o;
2436                ecbdata.header = header.len ? &header : NULL;
2437                xpp.flags = o->xdl_opts;
2438                xecfg.ctxlen = o->context;
2439                xecfg.interhunkctxlen = o->interhunkcontext;
2440                xecfg.flags = XDL_EMIT_FUNCNAMES;
2441                if (DIFF_OPT_TST(o, FUNCCONTEXT))
2442                        xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2443                if (pe)
2444                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2445                if (!diffopts)
2446                        ;
2447                else if (skip_prefix(diffopts, "--unified=", &v))
2448                        xecfg.ctxlen = strtoul(v, NULL, 10);
2449                else if (skip_prefix(diffopts, "-u", &v))
2450                        xecfg.ctxlen = strtoul(v, NULL, 10);
2451                if (o->word_diff)
2452                        init_diff_words_data(&ecbdata, o, one, two);
2453                if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2454                                  &xpp, &xecfg))
2455                        die("unable to generate diff for %s", one->path);
2456                if (o->word_diff)
2457                        free_diff_words_data(&ecbdata);
2458                if (textconv_one)
2459                        free(mf1.ptr);
2460                if (textconv_two)
2461                        free(mf2.ptr);
2462                xdiff_clear_find_func(&xecfg);
2463        }
2464
2465 free_ab_and_return:
2466        strbuf_release(&header);
2467        diff_free_filespec_data(one);
2468        diff_free_filespec_data(two);
2469        free(a_one);
2470        free(b_two);
2471        return;
2472}
2473
2474static void builtin_diffstat(const char *name_a, const char *name_b,
2475                             struct diff_filespec *one,
2476                             struct diff_filespec *two,
2477                             struct diffstat_t *diffstat,
2478                             struct diff_options *o,
2479                             struct diff_filepair *p)
2480{
2481        mmfile_t mf1, mf2;
2482        struct diffstat_file *data;
2483        int same_contents;
2484        int complete_rewrite = 0;
2485
2486        if (!DIFF_PAIR_UNMERGED(p)) {
2487                if (p->status == DIFF_STATUS_MODIFIED && p->score)
2488                        complete_rewrite = 1;
2489        }
2490
2491        data = diffstat_add(diffstat, name_a, name_b);
2492        data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2493
2494        if (!one || !two) {
2495                data->is_unmerged = 1;
2496                return;
2497        }
2498
2499        same_contents = !hashcmp(one->sha1, two->sha1);
2500
2501        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2502                data->is_binary = 1;
2503                if (same_contents) {
2504                        data->added = 0;
2505                        data->deleted = 0;
2506                } else {
2507                        data->added = diff_filespec_size(two);
2508                        data->deleted = diff_filespec_size(one);
2509                }
2510        }
2511
2512        else if (complete_rewrite) {
2513                diff_populate_filespec(one, 0);
2514                diff_populate_filespec(two, 0);
2515                data->deleted = count_lines(one->data, one->size);
2516                data->added = count_lines(two->data, two->size);
2517        }
2518
2519        else if (!same_contents) {
2520                /* Crazy xdl interfaces.. */
2521                xpparam_t xpp;
2522                xdemitconf_t xecfg;
2523
2524                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2525                        die("unable to read files to diff");
2526
2527                memset(&xpp, 0, sizeof(xpp));
2528                memset(&xecfg, 0, sizeof(xecfg));
2529                xpp.flags = o->xdl_opts;
2530                xecfg.ctxlen = o->context;
2531                xecfg.interhunkctxlen = o->interhunkcontext;
2532                if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2533                                  &xpp, &xecfg))
2534                        die("unable to generate diffstat for %s", one->path);
2535        }
2536
2537        diff_free_filespec_data(one);
2538        diff_free_filespec_data(two);
2539}
2540
2541static void builtin_checkdiff(const char *name_a, const char *name_b,
2542                              const char *attr_path,
2543                              struct diff_filespec *one,
2544                              struct diff_filespec *two,
2545                              struct diff_options *o)
2546{
2547        mmfile_t mf1, mf2;
2548        struct checkdiff_t data;
2549
2550        if (!two)
2551                return;
2552
2553        memset(&data, 0, sizeof(data));
2554        data.filename = name_b ? name_b : name_a;
2555        data.lineno = 0;
2556        data.o = o;
2557        data.ws_rule = whitespace_rule(attr_path);
2558        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2559
2560        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2561                die("unable to read files to diff");
2562
2563        /*
2564         * All the other codepaths check both sides, but not checking
2565         * the "old" side here is deliberate.  We are checking the newly
2566         * introduced changes, and as long as the "new" side is text, we
2567         * can and should check what it introduces.
2568         */
2569        if (diff_filespec_is_binary(two))
2570                goto free_and_return;
2571        else {
2572                /* Crazy xdl interfaces.. */
2573                xpparam_t xpp;
2574                xdemitconf_t xecfg;
2575
2576                memset(&xpp, 0, sizeof(xpp));
2577                memset(&xecfg, 0, sizeof(xecfg));
2578                xecfg.ctxlen = 1; /* at least one context line */
2579                xpp.flags = 0;
2580                if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2581                                  &xpp, &xecfg))
2582                        die("unable to generate checkdiff for %s", one->path);
2583
2584                if (data.ws_rule & WS_BLANK_AT_EOF) {
2585                        struct emit_callback ecbdata;
2586                        int blank_at_eof;
2587
2588                        ecbdata.ws_rule = data.ws_rule;
2589                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2590                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2591
2592                        if (blank_at_eof) {
2593                                static char *err;
2594                                if (!err)
2595                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2596                                fprintf(o->file, "%s:%d: %s.\n",
2597                                        data.filename, blank_at_eof, err);
2598                                data.status = 1; /* report errors */
2599                        }
2600                }
2601        }
2602 free_and_return:
2603        diff_free_filespec_data(one);
2604        diff_free_filespec_data(two);
2605        if (data.status)
2606                DIFF_OPT_SET(o, CHECK_FAILED);
2607}
2608
2609struct diff_filespec *alloc_filespec(const char *path)
2610{
2611        int namelen = strlen(path);
2612        struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
2613
2614        memset(spec, 0, sizeof(*spec));
2615        spec->path = (char *)(spec + 1);
2616        memcpy(spec->path, path, namelen+1);
2617        spec->count = 1;
2618        spec->is_binary = -1;
2619        return spec;
2620}
2621
2622void free_filespec(struct diff_filespec *spec)
2623{
2624        if (!--spec->count) {
2625                diff_free_filespec_data(spec);
2626                free(spec);
2627        }
2628}
2629
2630void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2631                   int sha1_valid, unsigned short mode)
2632{
2633        if (mode) {
2634                spec->mode = canon_mode(mode);
2635                hashcpy(spec->sha1, sha1);
2636                spec->sha1_valid = sha1_valid;
2637        }
2638}
2639
2640/*
2641 * Given a name and sha1 pair, if the index tells us the file in
2642 * the work tree has that object contents, return true, so that
2643 * prepare_temp_file() does not have to inflate and extract.
2644 */
2645static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2646{
2647        const struct cache_entry *ce;
2648        struct stat st;
2649        int pos, len;
2650
2651        /*
2652         * We do not read the cache ourselves here, because the
2653         * benchmark with my previous version that always reads cache
2654         * shows that it makes things worse for diff-tree comparing
2655         * two linux-2.6 kernel trees in an already checked out work
2656         * tree.  This is because most diff-tree comparisons deal with
2657         * only a small number of files, while reading the cache is
2658         * expensive for a large project, and its cost outweighs the
2659         * savings we get by not inflating the object to a temporary
2660         * file.  Practically, this code only helps when we are used
2661         * by diff-cache --cached, which does read the cache before
2662         * calling us.
2663         */
2664        if (!active_cache)
2665                return 0;
2666
2667        /* We want to avoid the working directory if our caller
2668         * doesn't need the data in a normal file, this system
2669         * is rather slow with its stat/open/mmap/close syscalls,
2670         * and the object is contained in a pack file.  The pack
2671         * is probably already open and will be faster to obtain
2672         * the data through than the working directory.  Loose
2673         * objects however would tend to be slower as they need
2674         * to be individually opened and inflated.
2675         */
2676        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2677                return 0;
2678
2679        len = strlen(name);
2680        pos = cache_name_pos(name, len);
2681        if (pos < 0)
2682                return 0;
2683        ce = active_cache[pos];
2684
2685        /*
2686         * This is not the sha1 we are looking for, or
2687         * unreusable because it is not a regular file.
2688         */
2689        if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2690                return 0;
2691
2692        /*
2693         * If ce is marked as "assume unchanged", there is no
2694         * guarantee that work tree matches what we are looking for.
2695         */
2696        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2697                return 0;
2698
2699        /*
2700         * If ce matches the file in the work tree, we can reuse it.
2701         */
2702        if (ce_uptodate(ce) ||
2703            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2704                return 1;
2705
2706        return 0;
2707}
2708
2709static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2710{
2711        int len;
2712        char *data = xmalloc(100), *dirty = "";
2713
2714        /* Are we looking at the work tree? */
2715        if (s->dirty_submodule)
2716                dirty = "-dirty";
2717
2718        len = snprintf(data, 100,
2719                       "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2720        s->data = data;
2721        s->size = len;
2722        s->should_free = 1;
2723        if (size_only) {
2724                s->data = NULL;
2725                free(data);
2726        }
2727        return 0;
2728}
2729
2730/*
2731 * While doing rename detection and pickaxe operation, we may need to
2732 * grab the data for the blob (or file) for our own in-core comparison.
2733 * diff_filespec has data and size fields for this purpose.
2734 */
2735int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
2736{
2737        int size_only = flags & CHECK_SIZE_ONLY;
2738        int err = 0;
2739        /*
2740         * demote FAIL to WARN to allow inspecting the situation
2741         * instead of refusing.
2742         */
2743        enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
2744                                    ? SAFE_CRLF_WARN
2745                                    : safe_crlf);
2746
2747        if (!DIFF_FILE_VALID(s))
2748                die("internal error: asking to populate invalid file.");
2749        if (S_ISDIR(s->mode))
2750                return -1;
2751
2752        if (s->data)
2753                return 0;
2754
2755        if (size_only && 0 < s->size)
2756                return 0;
2757
2758        if (S_ISGITLINK(s->mode))
2759                return diff_populate_gitlink(s, size_only);
2760
2761        if (!s->sha1_valid ||
2762            reuse_worktree_file(s->path, s->sha1, 0)) {
2763                struct strbuf buf = STRBUF_INIT;
2764                struct stat st;
2765                int fd;
2766
2767                if (lstat(s->path, &st) < 0) {
2768                        if (errno == ENOENT) {
2769                        err_empty:
2770                                err = -1;
2771                        empty:
2772                                s->data = (char *)"";
2773                                s->size = 0;
2774                                return err;
2775                        }
2776                }
2777                s->size = xsize_t(st.st_size);
2778                if (!s->size)
2779                        goto empty;
2780                if (S_ISLNK(st.st_mode)) {
2781                        struct strbuf sb = STRBUF_INIT;
2782
2783                        if (strbuf_readlink(&sb, s->path, s->size))
2784                                goto err_empty;
2785                        s->size = sb.len;
2786                        s->data = strbuf_detach(&sb, NULL);
2787                        s->should_free = 1;
2788                        return 0;
2789                }
2790                if (size_only)
2791                        return 0;
2792                if ((flags & CHECK_BINARY) &&
2793                    s->size > big_file_threshold && s->is_binary == -1) {
2794                        s->is_binary = 1;
2795                        return 0;
2796                }
2797                fd = open(s->path, O_RDONLY);
2798                if (fd < 0)
2799                        goto err_empty;
2800                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2801                close(fd);
2802                s->should_munmap = 1;
2803
2804                /*
2805                 * Convert from working tree format to canonical git format
2806                 */
2807                if (convert_to_git(s->path, s->data, s->size, &buf, crlf_warn)) {
2808                        size_t size = 0;
2809                        munmap(s->data, s->size);
2810                        s->should_munmap = 0;
2811                        s->data = strbuf_detach(&buf, &size);
2812                        s->size = size;
2813                        s->should_free = 1;
2814                }
2815        }
2816        else {
2817                enum object_type type;
2818                if (size_only || (flags & CHECK_BINARY)) {
2819                        type = sha1_object_info(s->sha1, &s->size);
2820                        if (type < 0)
2821                                die("unable to read %s", sha1_to_hex(s->sha1));
2822                        if (size_only)
2823                                return 0;
2824                        if (s->size > big_file_threshold && s->is_binary == -1) {
2825                                s->is_binary = 1;
2826                                return 0;
2827                        }
2828                }
2829                s->data = read_sha1_file(s->sha1, &type, &s->size);
2830                if (!s->data)
2831                        die("unable to read %s", sha1_to_hex(s->sha1));
2832                s->should_free = 1;
2833        }
2834        return 0;
2835}
2836
2837void diff_free_filespec_blob(struct diff_filespec *s)
2838{
2839        if (s->should_free)
2840                free(s->data);
2841        else if (s->should_munmap)
2842                munmap(s->data, s->size);
2843
2844        if (s->should_free || s->should_munmap) {
2845                s->should_free = s->should_munmap = 0;
2846                s->data = NULL;
2847        }
2848}
2849
2850void diff_free_filespec_data(struct diff_filespec *s)
2851{
2852        diff_free_filespec_blob(s);
2853        free(s->cnt_data);
2854        s->cnt_data = NULL;
2855}
2856
2857static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2858                           void *blob,
2859                           unsigned long size,
2860                           const unsigned char *sha1,
2861                           int mode)
2862{
2863        int fd;
2864        struct strbuf buf = STRBUF_INIT;
2865        struct strbuf template = STRBUF_INIT;
2866        char *path_dup = xstrdup(path);
2867        const char *base = basename(path_dup);
2868
2869        /* Generate "XXXXXX_basename.ext" */
2870        strbuf_addstr(&template, "XXXXXX_");
2871        strbuf_addstr(&template, base);
2872
2873        fd = mks_tempfile_ts(&temp->tempfile, template.buf, strlen(base) + 1);
2874        if (fd < 0)
2875                die_errno("unable to create temp-file");
2876        if (convert_to_working_tree(path,
2877                        (const char *)blob, (size_t)size, &buf)) {
2878                blob = buf.buf;
2879                size = buf.len;
2880        }
2881        if (write_in_full(fd, blob, size) != size)
2882                die_errno("unable to write temp-file");
2883        close_tempfile(&temp->tempfile);
2884        temp->name = get_tempfile_path(&temp->tempfile);
2885        sha1_to_hex_r(temp->hex, sha1);
2886        xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
2887        strbuf_release(&buf);
2888        strbuf_release(&template);
2889        free(path_dup);
2890}
2891
2892static struct diff_tempfile *prepare_temp_file(const char *name,
2893                struct diff_filespec *one)
2894{
2895        struct diff_tempfile *temp = claim_diff_tempfile();
2896
2897        if (!DIFF_FILE_VALID(one)) {
2898        not_a_valid_file:
2899                /* A '-' entry produces this for file-2, and
2900                 * a '+' entry produces this for file-1.
2901                 */
2902                temp->name = "/dev/null";
2903                xsnprintf(temp->hex, sizeof(temp->hex), ".");
2904                xsnprintf(temp->mode, sizeof(temp->mode), ".");
2905                return temp;
2906        }
2907
2908        if (!S_ISGITLINK(one->mode) &&
2909            (!one->sha1_valid ||
2910             reuse_worktree_file(name, one->sha1, 1))) {
2911                struct stat st;
2912                if (lstat(name, &st) < 0) {
2913                        if (errno == ENOENT)
2914                                goto not_a_valid_file;
2915                        die_errno("stat(%s)", name);
2916                }
2917                if (S_ISLNK(st.st_mode)) {
2918                        struct strbuf sb = STRBUF_INIT;
2919                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
2920                                die_errno("readlink(%s)", name);
2921                        prep_temp_blob(name, temp, sb.buf, sb.len,
2922                                       (one->sha1_valid ?
2923                                        one->sha1 : null_sha1),
2924                                       (one->sha1_valid ?
2925                                        one->mode : S_IFLNK));
2926                        strbuf_release(&sb);
2927                }
2928                else {
2929                        /* we can borrow from the file in the work tree */
2930                        temp->name = name;
2931                        if (!one->sha1_valid)
2932                                sha1_to_hex_r(temp->hex, null_sha1);
2933                        else
2934                                sha1_to_hex_r(temp->hex, one->sha1);
2935                        /* Even though we may sometimes borrow the
2936                         * contents from the work tree, we always want
2937                         * one->mode.  mode is trustworthy even when
2938                         * !(one->sha1_valid), as long as
2939                         * DIFF_FILE_VALID(one).
2940                         */
2941                        xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
2942                }
2943                return temp;
2944        }
2945        else {
2946                if (diff_populate_filespec(one, 0))
2947                        die("cannot read data blob for %s", one->path);
2948                prep_temp_blob(name, temp, one->data, one->size,
2949                               one->sha1, one->mode);
2950        }
2951        return temp;
2952}
2953
2954static void add_external_diff_name(struct argv_array *argv,
2955                                   const char *name,
2956                                   struct diff_filespec *df)
2957{
2958        struct diff_tempfile *temp = prepare_temp_file(name, df);
2959        argv_array_push(argv, temp->name);
2960        argv_array_push(argv, temp->hex);
2961        argv_array_push(argv, temp->mode);
2962}
2963
2964/* An external diff command takes:
2965 *
2966 * diff-cmd name infile1 infile1-sha1 infile1-mode \
2967 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2968 *
2969 */
2970static void run_external_diff(const char *pgm,
2971                              const char *name,
2972                              const char *other,
2973                              struct diff_filespec *one,
2974                              struct diff_filespec *two,
2975                              const char *xfrm_msg,
2976                              int complete_rewrite,
2977                              struct diff_options *o)
2978{
2979        struct argv_array argv = ARGV_ARRAY_INIT;
2980        struct argv_array env = ARGV_ARRAY_INIT;
2981        struct diff_queue_struct *q = &diff_queued_diff;
2982
2983        argv_array_push(&argv, pgm);
2984        argv_array_push(&argv, name);
2985
2986        if (one && two) {
2987                add_external_diff_name(&argv, name, one);
2988                if (!other)
2989                        add_external_diff_name(&argv, name, two);
2990                else {
2991                        add_external_diff_name(&argv, other, two);
2992                        argv_array_push(&argv, other);
2993                        argv_array_push(&argv, xfrm_msg);
2994                }
2995        }
2996
2997        argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
2998        argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
2999
3000        if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
3001                die(_("external diff died, stopping at %s"), name);
3002
3003        remove_tempfile();
3004        argv_array_clear(&argv);
3005        argv_array_clear(&env);
3006}
3007
3008static int similarity_index(struct diff_filepair *p)
3009{
3010        return p->score * 100 / MAX_SCORE;
3011}
3012
3013static void fill_metainfo(struct strbuf *msg,
3014                          const char *name,
3015                          const char *other,
3016                          struct diff_filespec *one,
3017                          struct diff_filespec *two,
3018                          struct diff_options *o,
3019                          struct diff_filepair *p,
3020                          int *must_show_header,
3021                          int use_color)
3022{
3023        const char *set = diff_get_color(use_color, DIFF_METAINFO);
3024        const char *reset = diff_get_color(use_color, DIFF_RESET);
3025        const char *line_prefix = diff_line_prefix(o);
3026
3027        *must_show_header = 1;
3028        strbuf_init(msg, PATH_MAX * 2 + 300);
3029        switch (p->status) {
3030        case DIFF_STATUS_COPIED:
3031                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3032                            line_prefix, set, similarity_index(p));
3033                strbuf_addf(msg, "%s\n%s%scopy from ",
3034                            reset,  line_prefix, set);
3035                quote_c_style(name, msg, NULL, 0);
3036                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
3037                quote_c_style(other, msg, NULL, 0);
3038                strbuf_addf(msg, "%s\n", reset);
3039                break;
3040        case DIFF_STATUS_RENAMED:
3041                strbuf_addf(msg, "%s%ssimilarity index %d%%",
3042                            line_prefix, set, similarity_index(p));
3043                strbuf_addf(msg, "%s\n%s%srename from ",
3044                            reset, line_prefix, set);
3045                quote_c_style(name, msg, NULL, 0);
3046                strbuf_addf(msg, "%s\n%s%srename to ",
3047                            reset, line_prefix, set);
3048                quote_c_style(other, msg, NULL, 0);
3049                strbuf_addf(msg, "%s\n", reset);
3050                break;
3051        case DIFF_STATUS_MODIFIED:
3052                if (p->score) {
3053                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3054                                    line_prefix,
3055                                    set, similarity_index(p), reset);
3056                        break;
3057                }
3058                /* fallthru */
3059        default:
3060                *must_show_header = 0;
3061        }
3062        if (one && two && hashcmp(one->sha1, two->sha1)) {
3063                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3064
3065                if (DIFF_OPT_TST(o, BINARY)) {
3066                        mmfile_t mf;
3067                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3068                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3069                                abbrev = 40;
3070                }
3071                strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
3072                            find_unique_abbrev(one->sha1, abbrev));
3073                strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
3074                if (one->mode == two->mode)
3075                        strbuf_addf(msg, " %06o", one->mode);
3076                strbuf_addf(msg, "%s\n", reset);
3077        }
3078}
3079
3080static void run_diff_cmd(const char *pgm,
3081                         const char *name,
3082                         const char *other,
3083                         const char *attr_path,
3084                         struct diff_filespec *one,
3085                         struct diff_filespec *two,
3086                         struct strbuf *msg,
3087                         struct diff_options *o,
3088                         struct diff_filepair *p)
3089{
3090        const char *xfrm_msg = NULL;
3091        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3092        int must_show_header = 0;
3093
3094
3095        if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3096                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3097                if (drv && drv->external)
3098                        pgm = drv->external;
3099        }
3100
3101        if (msg) {
3102                /*
3103                 * don't use colors when the header is intended for an
3104                 * external diff driver
3105                 */
3106                fill_metainfo(msg, name, other, one, two, o, p,
3107                              &must_show_header,
3108                              want_color(o->use_color) && !pgm);
3109                xfrm_msg = msg->len ? msg->buf : NULL;
3110        }
3111
3112        if (pgm) {
3113                run_external_diff(pgm, name, other, one, two, xfrm_msg,
3114                                  complete_rewrite, o);
3115                return;
3116        }
3117        if (one && two)
3118                builtin_diff(name, other ? other : name,
3119                             one, two, xfrm_msg, must_show_header,
3120                             o, complete_rewrite);
3121        else
3122                fprintf(o->file, "* Unmerged path %s\n", name);
3123}
3124
3125static void diff_fill_sha1_info(struct diff_filespec *one)
3126{
3127        if (DIFF_FILE_VALID(one)) {
3128                if (!one->sha1_valid) {
3129                        struct stat st;
3130                        if (one->is_stdin) {
3131                                hashcpy(one->sha1, null_sha1);
3132                                return;
3133                        }
3134                        if (lstat(one->path, &st) < 0)
3135                                die_errno("stat '%s'", one->path);
3136                        if (index_path(one->sha1, one->path, &st, 0))
3137                                die("cannot hash %s", one->path);
3138                }
3139        }
3140        else
3141                hashclr(one->sha1);
3142}
3143
3144static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3145{
3146        /* Strip the prefix but do not molest /dev/null and absolute paths */
3147        if (*namep && **namep != '/') {
3148                *namep += prefix_length;
3149                if (**namep == '/')
3150                        ++*namep;
3151        }
3152        if (*otherp && **otherp != '/') {
3153                *otherp += prefix_length;
3154                if (**otherp == '/')
3155                        ++*otherp;
3156        }
3157}
3158
3159static void run_diff(struct diff_filepair *p, struct diff_options *o)
3160{
3161        const char *pgm = external_diff();
3162        struct strbuf msg;
3163        struct diff_filespec *one = p->one;
3164        struct diff_filespec *two = p->two;
3165        const char *name;
3166        const char *other;
3167        const char *attr_path;
3168
3169        name  = p->one->path;
3170        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3171        attr_path = name;
3172        if (o->prefix_length)
3173                strip_prefix(o->prefix_length, &name, &other);
3174
3175        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3176                pgm = NULL;
3177
3178        if (DIFF_PAIR_UNMERGED(p)) {
3179                run_diff_cmd(pgm, name, NULL, attr_path,
3180                             NULL, NULL, NULL, o, p);
3181                return;
3182        }
3183
3184        diff_fill_sha1_info(one);
3185        diff_fill_sha1_info(two);
3186
3187        if (!pgm &&
3188            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3189            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3190                /*
3191                 * a filepair that changes between file and symlink
3192                 * needs to be split into deletion and creation.
3193                 */
3194                struct diff_filespec *null = alloc_filespec(two->path);
3195                run_diff_cmd(NULL, name, other, attr_path,
3196                             one, null, &msg, o, p);
3197                free(null);
3198                strbuf_release(&msg);
3199
3200                null = alloc_filespec(one->path);
3201                run_diff_cmd(NULL, name, other, attr_path,
3202                             null, two, &msg, o, p);
3203                free(null);
3204        }
3205        else
3206                run_diff_cmd(pgm, name, other, attr_path,
3207                             one, two, &msg, o, p);
3208
3209        strbuf_release(&msg);
3210}
3211
3212static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3213                         struct diffstat_t *diffstat)
3214{
3215        const char *name;
3216        const char *other;
3217
3218        if (DIFF_PAIR_UNMERGED(p)) {
3219                /* unmerged */
3220                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3221                return;
3222        }
3223
3224        name = p->one->path;
3225        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3226
3227        if (o->prefix_length)
3228                strip_prefix(o->prefix_length, &name, &other);
3229
3230        diff_fill_sha1_info(p->one);
3231        diff_fill_sha1_info(p->two);
3232
3233        builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3234}
3235
3236static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3237{
3238        const char *name;
3239        const char *other;
3240        const char *attr_path;
3241
3242        if (DIFF_PAIR_UNMERGED(p)) {
3243                /* unmerged */
3244                return;
3245        }
3246
3247        name = p->one->path;
3248        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3249        attr_path = other ? other : name;
3250
3251        if (o->prefix_length)
3252                strip_prefix(o->prefix_length, &name, &other);
3253
3254        diff_fill_sha1_info(p->one);
3255        diff_fill_sha1_info(p->two);
3256
3257        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3258}
3259
3260void diff_setup(struct diff_options *options)
3261{
3262        memcpy(options, &default_diff_options, sizeof(*options));
3263
3264        options->file = stdout;
3265
3266        options->line_termination = '\n';
3267        options->break_opt = -1;
3268        options->rename_limit = -1;
3269        options->dirstat_permille = diff_dirstat_permille_default;
3270        options->context = diff_context_default;
3271        options->ws_error_highlight = WSEH_NEW;
3272        DIFF_OPT_SET(options, RENAME_EMPTY);
3273
3274        /* pathchange left =NULL by default */
3275        options->change = diff_change;
3276        options->add_remove = diff_addremove;
3277        options->use_color = diff_use_color_default;
3278        options->detect_rename = diff_detect_rename_default;
3279        options->xdl_opts |= diff_algorithm;
3280
3281        options->orderfile = diff_order_file_cfg;
3282
3283        if (diff_no_prefix) {
3284                options->a_prefix = options->b_prefix = "";
3285        } else if (!diff_mnemonic_prefix) {
3286                options->a_prefix = "a/";
3287                options->b_prefix = "b/";
3288        }
3289}
3290
3291void diff_setup_done(struct diff_options *options)
3292{
3293        int count = 0;
3294
3295        if (options->set_default)
3296                options->set_default(options);
3297
3298        if (options->output_format & DIFF_FORMAT_NAME)
3299                count++;
3300        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3301                count++;
3302        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3303                count++;
3304        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3305                count++;
3306        if (count > 1)
3307                die("--name-only, --name-status, --check and -s are mutually exclusive");
3308
3309        /*
3310         * Most of the time we can say "there are changes"
3311         * only by checking if there are changed paths, but
3312         * --ignore-whitespace* options force us to look
3313         * inside contents.
3314         */
3315
3316        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3317            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3318            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3319                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3320        else
3321                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3322
3323        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3324                options->detect_rename = DIFF_DETECT_COPY;
3325
3326        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3327                options->prefix = NULL;
3328        if (options->prefix)
3329                options->prefix_length = strlen(options->prefix);
3330        else
3331                options->prefix_length = 0;
3332
3333        if (options->output_format & (DIFF_FORMAT_NAME |
3334                                      DIFF_FORMAT_NAME_STATUS |
3335                                      DIFF_FORMAT_CHECKDIFF |
3336                                      DIFF_FORMAT_NO_OUTPUT))
3337                options->output_format &= ~(DIFF_FORMAT_RAW |
3338                                            DIFF_FORMAT_NUMSTAT |
3339                                            DIFF_FORMAT_DIFFSTAT |
3340                                            DIFF_FORMAT_SHORTSTAT |
3341                                            DIFF_FORMAT_DIRSTAT |
3342                                            DIFF_FORMAT_SUMMARY |
3343                                            DIFF_FORMAT_PATCH);
3344
3345        /*
3346         * These cases always need recursive; we do not drop caller-supplied
3347         * recursive bits for other formats here.
3348         */
3349        if (options->output_format & (DIFF_FORMAT_PATCH |
3350                                      DIFF_FORMAT_NUMSTAT |
3351                                      DIFF_FORMAT_DIFFSTAT |
3352                                      DIFF_FORMAT_SHORTSTAT |
3353                                      DIFF_FORMAT_DIRSTAT |
3354                                      DIFF_FORMAT_SUMMARY |
3355                                      DIFF_FORMAT_CHECKDIFF))
3356                DIFF_OPT_SET(options, RECURSIVE);
3357        /*
3358         * Also pickaxe would not work very well if you do not say recursive
3359         */
3360        if (options->pickaxe)
3361                DIFF_OPT_SET(options, RECURSIVE);
3362        /*
3363         * When patches are generated, submodules diffed against the work tree
3364         * must be checked for dirtiness too so it can be shown in the output
3365         */
3366        if (options->output_format & DIFF_FORMAT_PATCH)
3367                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3368
3369        if (options->detect_rename && options->rename_limit < 0)
3370                options->rename_limit = diff_rename_limit_default;
3371        if (options->setup & DIFF_SETUP_USE_CACHE) {
3372                if (!active_cache)
3373                        /* read-cache does not die even when it fails
3374                         * so it is safe for us to do this here.  Also
3375                         * it does not smudge active_cache or active_nr
3376                         * when it fails, so we do not have to worry about
3377                         * cleaning it up ourselves either.
3378                         */
3379                        read_cache();
3380        }
3381        if (options->abbrev <= 0 || 40 < options->abbrev)
3382                options->abbrev = 40; /* full */
3383
3384        /*
3385         * It does not make sense to show the first hit we happened
3386         * to have found.  It does not make sense not to return with
3387         * exit code in such a case either.
3388         */
3389        if (DIFF_OPT_TST(options, QUICK)) {
3390                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3391                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3392        }
3393
3394        options->diff_path_counter = 0;
3395
3396        if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
3397                die(_("--follow requires exactly one pathspec"));
3398}
3399
3400static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3401{
3402        char c, *eq;
3403        int len;
3404
3405        if (*arg != '-')
3406                return 0;
3407        c = *++arg;
3408        if (!c)
3409                return 0;
3410        if (c == arg_short) {
3411                c = *++arg;
3412                if (!c)
3413                        return 1;
3414                if (val && isdigit(c)) {
3415                        char *end;
3416                        int n = strtoul(arg, &end, 10);
3417                        if (*end)
3418                                return 0;
3419                        *val = n;
3420                        return 1;
3421                }
3422                return 0;
3423        }
3424        if (c != '-')
3425                return 0;
3426        arg++;
3427        eq = strchrnul(arg, '=');
3428        len = eq - arg;
3429        if (!len || strncmp(arg, arg_long, len))
3430                return 0;
3431        if (*eq) {
3432                int n;
3433                char *end;
3434                if (!isdigit(*++eq))
3435                        return 0;
3436                n = strtoul(eq, &end, 10);
3437                if (*end)
3438                        return 0;
3439                *val = n;
3440        }
3441        return 1;
3442}
3443
3444static int diff_scoreopt_parse(const char *opt);
3445
3446static inline int short_opt(char opt, const char **argv,
3447                            const char **optarg)
3448{
3449        const char *arg = argv[0];
3450        if (arg[0] != '-' || arg[1] != opt)
3451                return 0;
3452        if (arg[2] != '\0') {
3453                *optarg = arg + 2;
3454                return 1;
3455        }
3456        if (!argv[1])
3457                die("Option '%c' requires a value", opt);
3458        *optarg = argv[1];
3459        return 2;
3460}
3461
3462int parse_long_opt(const char *opt, const char **argv,
3463                   const char **optarg)
3464{
3465        const char *arg = argv[0];
3466        if (!skip_prefix(arg, "--", &arg))
3467                return 0;
3468        if (!skip_prefix(arg, opt, &arg))
3469                return 0;
3470        if (*arg == '=') { /* stuck form: --option=value */
3471                *optarg = arg + 1;
3472                return 1;
3473        }
3474        if (*arg != '\0')
3475                return 0;
3476        /* separate form: --option value */
3477        if (!argv[1])
3478                die("Option '--%s' requires a value", opt);
3479        *optarg = argv[1];
3480        return 2;
3481}
3482
3483static int stat_opt(struct diff_options *options, const char **av)
3484{
3485        const char *arg = av[0];
3486        char *end;
3487        int width = options->stat_width;
3488        int name_width = options->stat_name_width;
3489        int graph_width = options->stat_graph_width;
3490        int count = options->stat_count;
3491        int argcount = 1;
3492
3493        if (!skip_prefix(arg, "--stat", &arg))
3494                die("BUG: stat option does not begin with --stat: %s", arg);
3495        end = (char *)arg;
3496
3497        switch (*arg) {
3498        case '-':
3499                if (skip_prefix(arg, "-width", &arg)) {
3500                        if (*arg == '=')
3501                                width = strtoul(arg + 1, &end, 10);
3502                        else if (!*arg && !av[1])
3503                                die("Option '--stat-width' requires a value");
3504                        else if (!*arg) {
3505                                width = strtoul(av[1], &end, 10);
3506                                argcount = 2;
3507                        }
3508                } else if (skip_prefix(arg, "-name-width", &arg)) {
3509                        if (*arg == '=')
3510                                name_width = strtoul(arg + 1, &end, 10);
3511                        else if (!*arg && !av[1])
3512                                die("Option '--stat-name-width' requires a value");
3513                        else if (!*arg) {
3514                                name_width = strtoul(av[1], &end, 10);
3515                                argcount = 2;
3516                        }
3517                } else if (skip_prefix(arg, "-graph-width", &arg)) {
3518                        if (*arg == '=')
3519                                graph_width = strtoul(arg + 1, &end, 10);
3520                        else if (!*arg && !av[1])
3521                                die("Option '--stat-graph-width' requires a value");
3522                        else if (!*arg) {
3523                                graph_width = strtoul(av[1], &end, 10);
3524                                argcount = 2;
3525                        }
3526                } else if (skip_prefix(arg, "-count", &arg)) {
3527                        if (*arg == '=')
3528                                count = strtoul(arg + 1, &end, 10);
3529                        else if (!*arg && !av[1])
3530                                die("Option '--stat-count' requires a value");
3531                        else if (!*arg) {
3532                                count = strtoul(av[1], &end, 10);
3533                                argcount = 2;
3534                        }
3535                }
3536                break;
3537        case '=':
3538                width = strtoul(arg+1, &end, 10);
3539                if (*end == ',')
3540                        name_width = strtoul(end+1, &end, 10);
3541                if (*end == ',')
3542                        count = strtoul(end+1, &end, 10);
3543        }
3544
3545        /* Important! This checks all the error cases! */
3546        if (*end)
3547                return 0;
3548        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3549        options->stat_name_width = name_width;
3550        options->stat_graph_width = graph_width;
3551        options->stat_width = width;
3552        options->stat_count = count;
3553        return argcount;
3554}
3555
3556static int parse_dirstat_opt(struct diff_options *options, const char *params)
3557{
3558        struct strbuf errmsg = STRBUF_INIT;
3559        if (parse_dirstat_params(options, params, &errmsg))
3560                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3561                    errmsg.buf);
3562        strbuf_release(&errmsg);
3563        /*
3564         * The caller knows a dirstat-related option is given from the command
3565         * line; allow it to say "return this_function();"
3566         */
3567        options->output_format |= DIFF_FORMAT_DIRSTAT;
3568        return 1;
3569}
3570
3571static int parse_submodule_opt(struct diff_options *options, const char *value)
3572{
3573        if (parse_submodule_params(options, value))
3574                die(_("Failed to parse --submodule option parameter: '%s'"),
3575                        value);
3576        return 1;
3577}
3578
3579static const char diff_status_letters[] = {
3580        DIFF_STATUS_ADDED,
3581        DIFF_STATUS_COPIED,
3582        DIFF_STATUS_DELETED,
3583        DIFF_STATUS_MODIFIED,
3584        DIFF_STATUS_RENAMED,
3585        DIFF_STATUS_TYPE_CHANGED,
3586        DIFF_STATUS_UNKNOWN,
3587        DIFF_STATUS_UNMERGED,
3588        DIFF_STATUS_FILTER_AON,
3589        DIFF_STATUS_FILTER_BROKEN,
3590        '\0',
3591};
3592
3593static unsigned int filter_bit['Z' + 1];
3594
3595static void prepare_filter_bits(void)
3596{
3597        int i;
3598
3599        if (!filter_bit[DIFF_STATUS_ADDED]) {
3600                for (i = 0; diff_status_letters[i]; i++)
3601                        filter_bit[(int) diff_status_letters[i]] = (1 << i);
3602        }
3603}
3604
3605static unsigned filter_bit_tst(char status, const struct diff_options *opt)
3606{
3607        return opt->filter & filter_bit[(int) status];
3608}
3609
3610static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
3611{
3612        int i, optch;
3613
3614        prepare_filter_bits();
3615
3616        /*
3617         * If there is a negation e.g. 'd' in the input, and we haven't
3618         * initialized the filter field with another --diff-filter, start
3619         * from full set of bits, except for AON.
3620         */
3621        if (!opt->filter) {
3622                for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3623                        if (optch < 'a' || 'z' < optch)
3624                                continue;
3625                        opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
3626                        opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
3627                        break;
3628                }
3629        }
3630
3631        for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3632                unsigned int bit;
3633                int negate;
3634
3635                if ('a' <= optch && optch <= 'z') {
3636                        negate = 1;
3637                        optch = toupper(optch);
3638                } else {
3639                        negate = 0;
3640                }
3641
3642                bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
3643                if (!bit)
3644                        return optarg[i];
3645                if (negate)
3646                        opt->filter &= ~bit;
3647                else
3648                        opt->filter |= bit;
3649        }
3650        return 0;
3651}
3652
3653static void enable_patch_output(int *fmt) {
3654        *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
3655        *fmt |= DIFF_FORMAT_PATCH;
3656}
3657
3658static int parse_one_token(const char **arg, const char *token)
3659{
3660        const char *rest;
3661        if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
3662                *arg = rest;
3663                return 1;
3664        }
3665        return 0;
3666}
3667
3668static int parse_ws_error_highlight(struct diff_options *opt, const char *arg)
3669{
3670        const char *orig_arg = arg;
3671        unsigned val = 0;
3672        while (*arg) {
3673                if (parse_one_token(&arg, "none"))
3674                        val = 0;
3675                else if (parse_one_token(&arg, "default"))
3676                        val = WSEH_NEW;
3677                else if (parse_one_token(&arg, "all"))
3678                        val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
3679                else if (parse_one_token(&arg, "new"))
3680                        val |= WSEH_NEW;
3681                else if (parse_one_token(&arg, "old"))
3682                        val |= WSEH_OLD;
3683                else if (parse_one_token(&arg, "context"))
3684                        val |= WSEH_CONTEXT;
3685                else {
3686                        error("unknown value after ws-error-highlight=%.*s",
3687                              (int)(arg - orig_arg), orig_arg);
3688                        return 0;
3689                }
3690                if (*arg)
3691                        arg++;
3692        }
3693        opt->ws_error_highlight = val;
3694        return 1;
3695}
3696
3697int diff_opt_parse(struct diff_options *options, const char **av, int ac)
3698{
3699        const char *arg = av[0];
3700        const char *optarg;
3701        int argcount;
3702
3703        /* Output format options */
3704        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
3705            || opt_arg(arg, 'U', "unified", &options->context))
3706                enable_patch_output(&options->output_format);
3707        else if (!strcmp(arg, "--raw"))
3708                options->output_format |= DIFF_FORMAT_RAW;
3709        else if (!strcmp(arg, "--patch-with-raw")) {
3710                enable_patch_output(&options->output_format);
3711                options->output_format |= DIFF_FORMAT_RAW;
3712        } else if (!strcmp(arg, "--numstat"))
3713                options->output_format |= DIFF_FORMAT_NUMSTAT;
3714        else if (!strcmp(arg, "--shortstat"))
3715                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3716        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3717                return parse_dirstat_opt(options, "");
3718        else if (skip_prefix(arg, "-X", &arg))
3719                return parse_dirstat_opt(options, arg);
3720        else if (skip_prefix(arg, "--dirstat=", &arg))
3721                return parse_dirstat_opt(options, arg);
3722        else if (!strcmp(arg, "--cumulative"))
3723                return parse_dirstat_opt(options, "cumulative");
3724        else if (!strcmp(arg, "--dirstat-by-file"))
3725                return parse_dirstat_opt(options, "files");
3726        else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
3727                parse_dirstat_opt(options, "files");
3728                return parse_dirstat_opt(options, arg);
3729        }
3730        else if (!strcmp(arg, "--check"))
3731                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3732        else if (!strcmp(arg, "--summary"))
3733                options->output_format |= DIFF_FORMAT_SUMMARY;
3734        else if (!strcmp(arg, "--patch-with-stat")) {
3735                enable_patch_output(&options->output_format);
3736                options->output_format |= DIFF_FORMAT_DIFFSTAT;
3737        } else if (!strcmp(arg, "--name-only"))
3738                options->output_format |= DIFF_FORMAT_NAME;
3739        else if (!strcmp(arg, "--name-status"))
3740                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3741        else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
3742                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3743        else if (starts_with(arg, "--stat"))
3744                /* --stat, --stat-width, --stat-name-width, or --stat-count */
3745                return stat_opt(options, av);
3746
3747        /* renames options */
3748        else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
3749                 !strcmp(arg, "--break-rewrites")) {
3750                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3751                        return error("invalid argument to -B: %s", arg+2);
3752        }
3753        else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
3754                 !strcmp(arg, "--find-renames")) {
3755                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3756                        return error("invalid argument to -M: %s", arg+2);
3757                options->detect_rename = DIFF_DETECT_RENAME;
3758        }
3759        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3760                options->irreversible_delete = 1;
3761        }
3762        else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
3763                 !strcmp(arg, "--find-copies")) {
3764                if (options->detect_rename == DIFF_DETECT_COPY)
3765                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3766                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3767                        return error("invalid argument to -C: %s", arg+2);
3768                options->detect_rename = DIFF_DETECT_COPY;
3769        }
3770        else if (!strcmp(arg, "--no-renames"))
3771                options->detect_rename = 0;
3772        else if (!strcmp(arg, "--rename-empty"))
3773                DIFF_OPT_SET(options, RENAME_EMPTY);
3774        else if (!strcmp(arg, "--no-rename-empty"))
3775                DIFF_OPT_CLR(options, RENAME_EMPTY);
3776        else if (!strcmp(arg, "--relative"))
3777                DIFF_OPT_SET(options, RELATIVE_NAME);
3778        else if (skip_prefix(arg, "--relative=", &arg)) {
3779                DIFF_OPT_SET(options, RELATIVE_NAME);
3780                options->prefix = arg;
3781        }
3782
3783        /* xdiff options */
3784        else if (!strcmp(arg, "--minimal"))
3785                DIFF_XDL_SET(options, NEED_MINIMAL);
3786        else if (!strcmp(arg, "--no-minimal"))
3787                DIFF_XDL_CLR(options, NEED_MINIMAL);
3788        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3789                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3790        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3791                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3792        else if (!strcmp(arg, "--ignore-space-at-eol"))
3793                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3794        else if (!strcmp(arg, "--ignore-blank-lines"))
3795                DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
3796        else if (!strcmp(arg, "--patience"))
3797                options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3798        else if (!strcmp(arg, "--histogram"))
3799                options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3800        else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
3801                long value = parse_algorithm_value(optarg);
3802                if (value < 0)
3803                        return error("option diff-algorithm accepts \"myers\", "
3804                                     "\"minimal\", \"patience\" and \"histogram\"");
3805                /* clear out previous settings */
3806                DIFF_XDL_CLR(options, NEED_MINIMAL);
3807                options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3808                options->xdl_opts |= value;
3809                return argcount;
3810        }
3811
3812        /* flags options */
3813        else if (!strcmp(arg, "--binary")) {
3814                enable_patch_output(&options->output_format);
3815                DIFF_OPT_SET(options, BINARY);
3816        }
3817        else if (!strcmp(arg, "--full-index"))
3818                DIFF_OPT_SET(options, FULL_INDEX);
3819        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3820                DIFF_OPT_SET(options, TEXT);
3821        else if (!strcmp(arg, "-R"))
3822                DIFF_OPT_SET(options, REVERSE_DIFF);
3823        else if (!strcmp(arg, "--find-copies-harder"))
3824                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3825        else if (!strcmp(arg, "--follow"))
3826                DIFF_OPT_SET(options, FOLLOW_RENAMES);
3827        else if (!strcmp(arg, "--no-follow")) {
3828                DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3829                DIFF_OPT_CLR(options, DEFAULT_FOLLOW_RENAMES);
3830        } else if (!strcmp(arg, "--color"))
3831                options->use_color = 1;
3832        else if (skip_prefix(arg, "--color=", &arg)) {
3833                int value = git_config_colorbool(NULL, arg);
3834                if (value < 0)
3835                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
3836                options->use_color = value;
3837        }
3838        else if (!strcmp(arg, "--no-color"))
3839                options->use_color = 0;
3840        else if (!strcmp(arg, "--color-words")) {
3841                options->use_color = 1;
3842                options->word_diff = DIFF_WORDS_COLOR;
3843        }
3844        else if (skip_prefix(arg, "--color-words=", &arg)) {
3845                options->use_color = 1;
3846                options->word_diff = DIFF_WORDS_COLOR;
3847                options->word_regex = arg;
3848        }
3849        else if (!strcmp(arg, "--word-diff")) {
3850                if (options->word_diff == DIFF_WORDS_NONE)
3851                        options->word_diff = DIFF_WORDS_PLAIN;
3852        }
3853        else if (skip_prefix(arg, "--word-diff=", &arg)) {
3854                if (!strcmp(arg, "plain"))
3855                        options->word_diff = DIFF_WORDS_PLAIN;
3856                else if (!strcmp(arg, "color")) {
3857                        options->use_color = 1;
3858                        options->word_diff = DIFF_WORDS_COLOR;
3859                }
3860                else if (!strcmp(arg, "porcelain"))
3861                        options->word_diff = DIFF_WORDS_PORCELAIN;
3862                else if (!strcmp(arg, "none"))
3863                        options->word_diff = DIFF_WORDS_NONE;
3864                else
3865                        die("bad --word-diff argument: %s", arg);
3866        }
3867        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3868                if (options->word_diff == DIFF_WORDS_NONE)
3869                        options->word_diff = DIFF_WORDS_PLAIN;
3870                options->word_regex = optarg;
3871                return argcount;
3872        }
3873        else if (!strcmp(arg, "--exit-code"))
3874                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3875        else if (!strcmp(arg, "--quiet"))
3876                DIFF_OPT_SET(options, QUICK);
3877        else if (!strcmp(arg, "--ext-diff"))
3878                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3879        else if (!strcmp(arg, "--no-ext-diff"))
3880                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3881        else if (!strcmp(arg, "--textconv"))
3882                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3883        else if (!strcmp(arg, "--no-textconv"))
3884                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3885        else if (!strcmp(arg, "--ignore-submodules")) {
3886                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3887                handle_ignore_submodules_arg(options, "all");
3888        } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
3889                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3890                handle_ignore_submodules_arg(options, arg);
3891        } else if (!strcmp(arg, "--submodule"))
3892                DIFF_OPT_SET(options, SUBMODULE_LOG);
3893        else if (skip_prefix(arg, "--submodule=", &arg))
3894                return parse_submodule_opt(options, arg);
3895        else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
3896                return parse_ws_error_highlight(options, arg);
3897
3898        /* misc options */
3899        else if (!strcmp(arg, "-z"))
3900                options->line_termination = 0;
3901        else if ((argcount = short_opt('l', av, &optarg))) {
3902                options->rename_limit = strtoul(optarg, NULL, 10);
3903                return argcount;
3904        }
3905        else if ((argcount = short_opt('S', av, &optarg))) {
3906                options->pickaxe = optarg;
3907                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3908                return argcount;
3909        } else if ((argcount = short_opt('G', av, &optarg))) {
3910                options->pickaxe = optarg;
3911                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3912                return argcount;
3913        }
3914        else if (!strcmp(arg, "--pickaxe-all"))
3915                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3916        else if (!strcmp(arg, "--pickaxe-regex"))
3917                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3918        else if ((argcount = short_opt('O', av, &optarg))) {
3919                options->orderfile = optarg;
3920                return argcount;
3921        }
3922        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3923                int offending = parse_diff_filter_opt(optarg, options);
3924                if (offending)
3925                        die("unknown change class '%c' in --diff-filter=%s",
3926                            offending, optarg);
3927                return argcount;
3928        }
3929        else if (!strcmp(arg, "--abbrev"))
3930                options->abbrev = DEFAULT_ABBREV;
3931        else if (skip_prefix(arg, "--abbrev=", &arg)) {
3932                options->abbrev = strtoul(arg, NULL, 10);
3933                if (options->abbrev < MINIMUM_ABBREV)
3934                        options->abbrev = MINIMUM_ABBREV;
3935                else if (40 < options->abbrev)
3936                        options->abbrev = 40;
3937        }
3938        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3939                options->a_prefix = optarg;
3940                return argcount;
3941        }
3942        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3943                options->b_prefix = optarg;
3944                return argcount;
3945        }
3946        else if (!strcmp(arg, "--no-prefix"))
3947                options->a_prefix = options->b_prefix = "";
3948        else if (opt_arg(arg, '\0', "inter-hunk-context",
3949                         &options->interhunkcontext))
3950                ;
3951        else if (!strcmp(arg, "-W"))
3952                DIFF_OPT_SET(options, FUNCCONTEXT);
3953        else if (!strcmp(arg, "--function-context"))
3954                DIFF_OPT_SET(options, FUNCCONTEXT);
3955        else if (!strcmp(arg, "--no-function-context"))
3956                DIFF_OPT_CLR(options, FUNCCONTEXT);
3957        else if ((argcount = parse_long_opt("output", av, &optarg))) {
3958                options->file = fopen(optarg, "w");
3959                if (!options->file)
3960                        die_errno("Could not open '%s'", optarg);
3961                options->close_file = 1;
3962                return argcount;
3963        } else
3964                return 0;
3965        return 1;
3966}
3967
3968int parse_rename_score(const char **cp_p)
3969{
3970        unsigned long num, scale;
3971        int ch, dot;
3972        const char *cp = *cp_p;
3973
3974        num = 0;
3975        scale = 1;
3976        dot = 0;
3977        for (;;) {
3978                ch = *cp;
3979                if ( !dot && ch == '.' ) {
3980                        scale = 1;
3981                        dot = 1;
3982                } else if ( ch == '%' ) {
3983                        scale = dot ? scale*100 : 100;
3984                        cp++;   /* % is always at the end */
3985                        break;
3986                } else if ( ch >= '0' && ch <= '9' ) {
3987                        if ( scale < 100000 ) {
3988                                scale *= 10;
3989                                num = (num*10) + (ch-'0');
3990                        }
3991                } else {
3992                        break;
3993                }
3994                cp++;
3995        }
3996        *cp_p = cp;
3997
3998        /* user says num divided by scale and we say internally that
3999         * is MAX_SCORE * num / scale.
4000         */
4001        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
4002}
4003
4004static int diff_scoreopt_parse(const char *opt)
4005{
4006        int opt1, opt2, cmd;
4007
4008        if (*opt++ != '-')
4009                return -1;
4010        cmd = *opt++;
4011        if (cmd == '-') {
4012                /* convert the long-form arguments into short-form versions */
4013                if (skip_prefix(opt, "break-rewrites", &opt)) {
4014                        if (*opt == 0 || *opt++ == '=')
4015                                cmd = 'B';
4016                } else if (skip_prefix(opt, "find-copies", &opt)) {
4017                        if (*opt == 0 || *opt++ == '=')
4018                                cmd = 'C';
4019                } else if (skip_prefix(opt, "find-renames", &opt)) {
4020                        if (*opt == 0 || *opt++ == '=')
4021                                cmd = 'M';
4022                }
4023        }
4024        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
4025                return -1; /* that is not a -M, -C, or -B option */
4026
4027        opt1 = parse_rename_score(&opt);
4028        if (cmd != 'B')
4029                opt2 = 0;
4030        else {
4031                if (*opt == 0)
4032                        opt2 = 0;
4033                else if (*opt != '/')
4034                        return -1; /* we expect -B80/99 or -B80 */
4035                else {
4036                        opt++;
4037                        opt2 = parse_rename_score(&opt);
4038                }
4039        }
4040        if (*opt != 0)
4041                return -1;
4042        return opt1 | (opt2 << 16);
4043}
4044
4045struct diff_queue_struct diff_queued_diff;
4046
4047void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
4048{
4049        ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
4050        queue->queue[queue->nr++] = dp;
4051}
4052
4053struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
4054                                 struct diff_filespec *one,
4055                                 struct diff_filespec *two)
4056{
4057        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
4058        dp->one = one;
4059        dp->two = two;
4060        if (queue)
4061                diff_q(queue, dp);
4062        return dp;
4063}
4064
4065void diff_free_filepair(struct diff_filepair *p)
4066{
4067        free_filespec(p->one);
4068        free_filespec(p->two);
4069        free(p);
4070}
4071
4072/* This is different from find_unique_abbrev() in that
4073 * it stuffs the result with dots for alignment.
4074 */
4075const char *diff_unique_abbrev(const unsigned char *sha1, int len)
4076{
4077        int abblen;
4078        const char *abbrev;
4079        if (len == 40)
4080                return sha1_to_hex(sha1);
4081
4082        abbrev = find_unique_abbrev(sha1, len);
4083        abblen = strlen(abbrev);
4084        if (abblen < 37) {
4085                static char hex[41];
4086                if (len < abblen && abblen <= len + 2)
4087                        xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
4088                else
4089                        xsnprintf(hex, sizeof(hex), "%s...", abbrev);
4090                return hex;
4091        }
4092        return sha1_to_hex(sha1);
4093}
4094
4095static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4096{
4097        int line_termination = opt->line_termination;
4098        int inter_name_termination = line_termination ? '\t' : '\0';
4099
4100        fprintf(opt->file, "%s", diff_line_prefix(opt));
4101        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4102                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4103                        diff_unique_abbrev(p->one->sha1, opt->abbrev));
4104                fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
4105        }
4106        if (p->score) {
4107                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4108                        inter_name_termination);
4109        } else {
4110                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4111        }
4112
4113        if (p->status == DIFF_STATUS_COPIED ||
4114            p->status == DIFF_STATUS_RENAMED) {
4115                const char *name_a, *name_b;
4116                name_a = p->one->path;
4117                name_b = p->two->path;
4118                strip_prefix(opt->prefix_length, &name_a, &name_b);
4119                write_name_quoted(name_a, opt->file, inter_name_termination);
4120                write_name_quoted(name_b, opt->file, line_termination);
4121        } else {
4122                const char *name_a, *name_b;
4123                name_a = p->one->mode ? p->one->path : p->two->path;
4124                name_b = NULL;
4125                strip_prefix(opt->prefix_length, &name_a, &name_b);
4126                write_name_quoted(name_a, opt->file, line_termination);
4127        }
4128}
4129
4130int diff_unmodified_pair(struct diff_filepair *p)
4131{
4132        /* This function is written stricter than necessary to support
4133         * the currently implemented transformers, but the idea is to
4134         * let transformers to produce diff_filepairs any way they want,
4135         * and filter and clean them up here before producing the output.
4136         */
4137        struct diff_filespec *one = p->one, *two = p->two;
4138
4139        if (DIFF_PAIR_UNMERGED(p))
4140                return 0; /* unmerged is interesting */
4141
4142        /* deletion, addition, mode or type change
4143         * and rename are all interesting.
4144         */
4145        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4146            DIFF_PAIR_MODE_CHANGED(p) ||
4147            strcmp(one->path, two->path))
4148                return 0;
4149
4150        /* both are valid and point at the same path.  that is, we are
4151         * dealing with a change.
4152         */
4153        if (one->sha1_valid && two->sha1_valid &&
4154            !hashcmp(one->sha1, two->sha1) &&
4155            !one->dirty_submodule && !two->dirty_submodule)
4156                return 1; /* no change */
4157        if (!one->sha1_valid && !two->sha1_valid)
4158                return 1; /* both look at the same file on the filesystem. */
4159        return 0;
4160}
4161
4162static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
4163{
4164        if (diff_unmodified_pair(p))
4165                return;
4166
4167        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4168            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4169                return; /* no tree diffs in patch format */
4170
4171        run_diff(p, o);
4172}
4173
4174static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
4175                            struct diffstat_t *diffstat)
4176{
4177        if (diff_unmodified_pair(p))
4178                return;
4179
4180        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4181            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4182                return; /* no useful stat for tree diffs */
4183
4184        run_diffstat(p, o, diffstat);
4185}
4186
4187static void diff_flush_checkdiff(struct diff_filepair *p,
4188                struct diff_options *o)
4189{
4190        if (diff_unmodified_pair(p))
4191                return;
4192
4193        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4194            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4195                return; /* nothing to check in tree diffs */
4196
4197        run_checkdiff(p, o);
4198}
4199
4200int diff_queue_is_empty(void)
4201{
4202        struct diff_queue_struct *q = &diff_queued_diff;
4203        int i;
4204        for (i = 0; i < q->nr; i++)
4205                if (!diff_unmodified_pair(q->queue[i]))
4206                        return 0;
4207        return 1;
4208}
4209
4210#if DIFF_DEBUG
4211void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4212{
4213        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4214                x, one ? one : "",
4215                s->path,
4216                DIFF_FILE_VALID(s) ? "valid" : "invalid",
4217                s->mode,
4218                s->sha1_valid ? sha1_to_hex(s->sha1) : "");
4219        fprintf(stderr, "queue[%d] %s size %lu\n",
4220                x, one ? one : "",
4221                s->size);
4222}
4223
4224void diff_debug_filepair(const struct diff_filepair *p, int i)
4225{
4226        diff_debug_filespec(p->one, i, "one");
4227        diff_debug_filespec(p->two, i, "two");
4228        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4229                p->score, p->status ? p->status : '?',
4230                p->one->rename_used, p->broken_pair);
4231}
4232
4233void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4234{
4235        int i;
4236        if (msg)
4237                fprintf(stderr, "%s\n", msg);
4238        fprintf(stderr, "q->nr = %d\n", q->nr);
4239        for (i = 0; i < q->nr; i++) {
4240                struct diff_filepair *p = q->queue[i];
4241                diff_debug_filepair(p, i);
4242        }
4243}
4244#endif
4245
4246static void diff_resolve_rename_copy(void)
4247{
4248        int i;
4249        struct diff_filepair *p;
4250        struct diff_queue_struct *q = &diff_queued_diff;
4251
4252        diff_debug_queue("resolve-rename-copy", q);
4253
4254        for (i = 0; i < q->nr; i++) {
4255                p = q->queue[i];
4256                p->status = 0; /* undecided */
4257                if (DIFF_PAIR_UNMERGED(p))
4258                        p->status = DIFF_STATUS_UNMERGED;
4259                else if (!DIFF_FILE_VALID(p->one))
4260                        p->status = DIFF_STATUS_ADDED;
4261                else if (!DIFF_FILE_VALID(p->two))
4262                        p->status = DIFF_STATUS_DELETED;
4263                else if (DIFF_PAIR_TYPE_CHANGED(p))
4264                        p->status = DIFF_STATUS_TYPE_CHANGED;
4265
4266                /* from this point on, we are dealing with a pair
4267                 * whose both sides are valid and of the same type, i.e.
4268                 * either in-place edit or rename/copy edit.
4269                 */
4270                else if (DIFF_PAIR_RENAME(p)) {
4271                        /*
4272                         * A rename might have re-connected a broken
4273                         * pair up, causing the pathnames to be the
4274                         * same again. If so, that's not a rename at
4275                         * all, just a modification..
4276                         *
4277                         * Otherwise, see if this source was used for
4278                         * multiple renames, in which case we decrement
4279                         * the count, and call it a copy.
4280                         */
4281                        if (!strcmp(p->one->path, p->two->path))
4282                                p->status = DIFF_STATUS_MODIFIED;
4283                        else if (--p->one->rename_used > 0)
4284                                p->status = DIFF_STATUS_COPIED;
4285                        else
4286                                p->status = DIFF_STATUS_RENAMED;
4287                }
4288                else if (hashcmp(p->one->sha1, p->two->sha1) ||
4289                         p->one->mode != p->two->mode ||
4290                         p->one->dirty_submodule ||
4291                         p->two->dirty_submodule ||
4292                         is_null_sha1(p->one->sha1))
4293                        p->status = DIFF_STATUS_MODIFIED;
4294                else {
4295                        /* This is a "no-change" entry and should not
4296                         * happen anymore, but prepare for broken callers.
4297                         */
4298                        error("feeding unmodified %s to diffcore",
4299                              p->one->path);
4300                        p->status = DIFF_STATUS_UNKNOWN;
4301                }
4302        }
4303        diff_debug_queue("resolve-rename-copy done", q);
4304}
4305
4306static int check_pair_status(struct diff_filepair *p)
4307{
4308        switch (p->status) {
4309        case DIFF_STATUS_UNKNOWN:
4310                return 0;
4311        case 0:
4312                die("internal error in diff-resolve-rename-copy");
4313        default:
4314                return 1;
4315        }
4316}
4317
4318static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4319{
4320        int fmt = opt->output_format;
4321
4322        if (fmt & DIFF_FORMAT_CHECKDIFF)
4323                diff_flush_checkdiff(p, opt);
4324        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4325                diff_flush_raw(p, opt);
4326        else if (fmt & DIFF_FORMAT_NAME) {
4327                const char *name_a, *name_b;
4328                name_a = p->two->path;
4329                name_b = NULL;
4330                strip_prefix(opt->prefix_length, &name_a, &name_b);
4331                write_name_quoted(name_a, opt->file, opt->line_termination);
4332        }
4333}
4334
4335static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4336{
4337        if (fs->mode)
4338                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4339        else
4340                fprintf(file, " %s ", newdelete);
4341        write_name_quoted(fs->path, file, '\n');
4342}
4343
4344
4345static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4346                const char *line_prefix)
4347{
4348        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4349                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4350                        p->two->mode, show_name ? ' ' : '\n');
4351                if (show_name) {
4352                        write_name_quoted(p->two->path, file, '\n');
4353                }
4354        }
4355}
4356
4357static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4358                        const char *line_prefix)
4359{
4360        char *names = pprint_rename(p->one->path, p->two->path);
4361
4362        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4363        free(names);
4364        show_mode_change(file, p, 0, line_prefix);
4365}
4366
4367static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4368{
4369        FILE *file = opt->file;
4370        const char *line_prefix = diff_line_prefix(opt);
4371
4372        switch(p->status) {
4373        case DIFF_STATUS_DELETED:
4374                fputs(line_prefix, file);
4375                show_file_mode_name(file, "delete", p->one);
4376                break;
4377        case DIFF_STATUS_ADDED:
4378                fputs(line_prefix, file);
4379                show_file_mode_name(file, "create", p->two);
4380                break;
4381        case DIFF_STATUS_COPIED:
4382                fputs(line_prefix, file);
4383                show_rename_copy(file, "copy", p, line_prefix);
4384                break;
4385        case DIFF_STATUS_RENAMED:
4386                fputs(line_prefix, file);
4387                show_rename_copy(file, "rename", p, line_prefix);
4388                break;
4389        default:
4390                if (p->score) {
4391                        fprintf(file, "%s rewrite ", line_prefix);
4392                        write_name_quoted(p->two->path, file, ' ');
4393                        fprintf(file, "(%d%%)\n", similarity_index(p));
4394                }
4395                show_mode_change(file, p, !p->score, line_prefix);
4396                break;
4397        }
4398}
4399
4400struct patch_id_t {
4401        git_SHA_CTX *ctx;
4402        int patchlen;
4403};
4404
4405static int remove_space(char *line, int len)
4406{
4407        int i;
4408        char *dst = line;
4409        unsigned char c;
4410
4411        for (i = 0; i < len; i++)
4412                if (!isspace((c = line[i])))
4413                        *dst++ = c;
4414
4415        return dst - line;
4416}
4417
4418static void patch_id_consume(void *priv, char *line, unsigned long len)
4419{
4420        struct patch_id_t *data = priv;
4421        int new_len;
4422
4423        /* Ignore line numbers when computing the SHA1 of the patch */
4424        if (starts_with(line, "@@ -"))
4425                return;
4426
4427        new_len = remove_space(line, len);
4428
4429        git_SHA1_Update(data->ctx, line, new_len);
4430        data->patchlen += new_len;
4431}
4432
4433/* returns 0 upon success, and writes result into sha1 */
4434static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
4435{
4436        struct diff_queue_struct *q = &diff_queued_diff;
4437        int i;
4438        git_SHA_CTX ctx;
4439        struct patch_id_t data;
4440        char buffer[PATH_MAX * 4 + 20];
4441
4442        git_SHA1_Init(&ctx);
4443        memset(&data, 0, sizeof(struct patch_id_t));
4444        data.ctx = &ctx;
4445
4446        for (i = 0; i < q->nr; i++) {
4447                xpparam_t xpp;
4448                xdemitconf_t xecfg;
4449                mmfile_t mf1, mf2;
4450                struct diff_filepair *p = q->queue[i];
4451                int len1, len2;
4452
4453                memset(&xpp, 0, sizeof(xpp));
4454                memset(&xecfg, 0, sizeof(xecfg));
4455                if (p->status == 0)
4456                        return error("internal diff status error");
4457                if (p->status == DIFF_STATUS_UNKNOWN)
4458                        continue;
4459                if (diff_unmodified_pair(p))
4460                        continue;
4461                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4462                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4463                        continue;
4464                if (DIFF_PAIR_UNMERGED(p))
4465                        continue;
4466
4467                diff_fill_sha1_info(p->one);
4468                diff_fill_sha1_info(p->two);
4469                if (fill_mmfile(&mf1, p->one) < 0 ||
4470                                fill_mmfile(&mf2, p->two) < 0)
4471                        return error("unable to read files to diff");
4472
4473                len1 = remove_space(p->one->path, strlen(p->one->path));
4474                len2 = remove_space(p->two->path, strlen(p->two->path));
4475                if (p->one->mode == 0)
4476                        len1 = snprintf(buffer, sizeof(buffer),
4477                                        "diff--gita/%.*sb/%.*s"
4478                                        "newfilemode%06o"
4479                                        "---/dev/null"
4480                                        "+++b/%.*s",
4481                                        len1, p->one->path,
4482                                        len2, p->two->path,
4483                                        p->two->mode,
4484                                        len2, p->two->path);
4485                else if (p->two->mode == 0)
4486                        len1 = snprintf(buffer, sizeof(buffer),
4487                                        "diff--gita/%.*sb/%.*s"
4488                                        "deletedfilemode%06o"
4489                                        "---a/%.*s"
4490                                        "+++/dev/null",
4491                                        len1, p->one->path,
4492                                        len2, p->two->path,
4493                                        p->one->mode,
4494                                        len1, p->one->path);
4495                else
4496                        len1 = snprintf(buffer, sizeof(buffer),
4497                                        "diff--gita/%.*sb/%.*s"
4498                                        "---a/%.*s"
4499                                        "+++b/%.*s",
4500                                        len1, p->one->path,
4501                                        len2, p->two->path,
4502                                        len1, p->one->path,
4503                                        len2, p->two->path);
4504                git_SHA1_Update(&ctx, buffer, len1);
4505
4506                if (diff_filespec_is_binary(p->one) ||
4507                    diff_filespec_is_binary(p->two)) {
4508                        git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4509                        git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4510                        continue;
4511                }
4512
4513                xpp.flags = 0;
4514                xecfg.ctxlen = 3;
4515                xecfg.flags = 0;
4516                if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4517                                  &xpp, &xecfg))
4518                        return error("unable to generate patch-id diff for %s",
4519                                     p->one->path);
4520        }
4521
4522        git_SHA1_Final(sha1, &ctx);
4523        return 0;
4524}
4525
4526int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4527{
4528        struct diff_queue_struct *q = &diff_queued_diff;
4529        int i;
4530        int result = diff_get_patch_id(options, sha1);
4531
4532        for (i = 0; i < q->nr; i++)
4533                diff_free_filepair(q->queue[i]);
4534
4535        free(q->queue);
4536        DIFF_QUEUE_CLEAR(q);
4537
4538        return result;
4539}
4540
4541static int is_summary_empty(const struct diff_queue_struct *q)
4542{
4543        int i;
4544
4545        for (i = 0; i < q->nr; i++) {
4546                const struct diff_filepair *p = q->queue[i];
4547
4548                switch (p->status) {
4549                case DIFF_STATUS_DELETED:
4550                case DIFF_STATUS_ADDED:
4551                case DIFF_STATUS_COPIED:
4552                case DIFF_STATUS_RENAMED:
4553                        return 0;
4554                default:
4555                        if (p->score)
4556                                return 0;
4557                        if (p->one->mode && p->two->mode &&
4558                            p->one->mode != p->two->mode)
4559                                return 0;
4560                        break;
4561                }
4562        }
4563        return 1;
4564}
4565
4566static const char rename_limit_warning[] =
4567"inexact rename detection was skipped due to too many files.";
4568
4569static const char degrade_cc_to_c_warning[] =
4570"only found copies from modified paths due to too many files.";
4571
4572static const char rename_limit_advice[] =
4573"you may want to set your %s variable to at least "
4574"%d and retry the command.";
4575
4576void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4577{
4578        if (degraded_cc)
4579                warning(degrade_cc_to_c_warning);
4580        else if (needed)
4581                warning(rename_limit_warning);
4582        else
4583                return;
4584        if (0 < needed && needed < 32767)
4585                warning(rename_limit_advice, varname, needed);
4586}
4587
4588void diff_flush(struct diff_options *options)
4589{
4590        struct diff_queue_struct *q = &diff_queued_diff;
4591        int i, output_format = options->output_format;
4592        int separator = 0;
4593        int dirstat_by_line = 0;
4594
4595        /*
4596         * Order: raw, stat, summary, patch
4597         * or:    name/name-status/checkdiff (other bits clear)
4598         */
4599        if (!q->nr)
4600                goto free_queue;
4601
4602        if (output_format & (DIFF_FORMAT_RAW |
4603                             DIFF_FORMAT_NAME |
4604                             DIFF_FORMAT_NAME_STATUS |
4605                             DIFF_FORMAT_CHECKDIFF)) {
4606                for (i = 0; i < q->nr; i++) {
4607                        struct diff_filepair *p = q->queue[i];
4608                        if (check_pair_status(p))
4609                                flush_one_pair(p, options);
4610                }
4611                separator++;
4612        }
4613
4614        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4615                dirstat_by_line = 1;
4616
4617        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4618            dirstat_by_line) {
4619                struct diffstat_t diffstat;
4620
4621                memset(&diffstat, 0, sizeof(struct diffstat_t));
4622                for (i = 0; i < q->nr; i++) {
4623                        struct diff_filepair *p = q->queue[i];
4624                        if (check_pair_status(p))
4625                                diff_flush_stat(p, options, &diffstat);
4626                }
4627                if (output_format & DIFF_FORMAT_NUMSTAT)
4628                        show_numstat(&diffstat, options);
4629                if (output_format & DIFF_FORMAT_DIFFSTAT)
4630                        show_stats(&diffstat, options);
4631                if (output_format & DIFF_FORMAT_SHORTSTAT)
4632                        show_shortstats(&diffstat, options);
4633                if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
4634                        show_dirstat_by_line(&diffstat, options);
4635                free_diffstat_info(&diffstat);
4636                separator++;
4637        }
4638        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4639                show_dirstat(options);
4640
4641        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4642                for (i = 0; i < q->nr; i++) {
4643                        diff_summary(options, q->queue[i]);
4644                }
4645                separator++;
4646        }
4647
4648        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4649            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4650            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4651                /*
4652                 * run diff_flush_patch for the exit status. setting
4653                 * options->file to /dev/null should be safe, because we
4654                 * aren't supposed to produce any output anyway.
4655                 */
4656                if (options->close_file)
4657                        fclose(options->file);
4658                options->file = fopen("/dev/null", "w");
4659                if (!options->file)
4660                        die_errno("Could not open /dev/null");
4661                options->close_file = 1;
4662                for (i = 0; i < q->nr; i++) {
4663                        struct diff_filepair *p = q->queue[i];
4664                        if (check_pair_status(p))
4665                                diff_flush_patch(p, options);
4666                        if (options->found_changes)
4667                                break;
4668                }
4669        }
4670
4671        if (output_format & DIFF_FORMAT_PATCH) {
4672                if (separator) {
4673                        fprintf(options->file, "%s%c",
4674                                diff_line_prefix(options),
4675                                options->line_termination);
4676                        if (options->stat_sep) {
4677                                /* attach patch instead of inline */
4678                                fputs(options->stat_sep, options->file);
4679                        }
4680                }
4681
4682                for (i = 0; i < q->nr; i++) {
4683                        struct diff_filepair *p = q->queue[i];
4684                        if (check_pair_status(p))
4685                                diff_flush_patch(p, options);
4686                }
4687        }
4688
4689        if (output_format & DIFF_FORMAT_CALLBACK)
4690                options->format_callback(q, options, options->format_callback_data);
4691
4692        for (i = 0; i < q->nr; i++)
4693                diff_free_filepair(q->queue[i]);
4694free_queue:
4695        free(q->queue);
4696        DIFF_QUEUE_CLEAR(q);
4697        if (options->close_file)
4698                fclose(options->file);
4699
4700        /*
4701         * Report the content-level differences with HAS_CHANGES;
4702         * diff_addremove/diff_change does not set the bit when
4703         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4704         */
4705        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4706                if (options->found_changes)
4707                        DIFF_OPT_SET(options, HAS_CHANGES);
4708                else
4709                        DIFF_OPT_CLR(options, HAS_CHANGES);
4710        }
4711}
4712
4713static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
4714{
4715        return (((p->status == DIFF_STATUS_MODIFIED) &&
4716                 ((p->score &&
4717                   filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
4718                  (!p->score &&
4719                   filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
4720                ((p->status != DIFF_STATUS_MODIFIED) &&
4721                 filter_bit_tst(p->status, options)));
4722}
4723
4724static void diffcore_apply_filter(struct diff_options *options)
4725{
4726        int i;
4727        struct diff_queue_struct *q = &diff_queued_diff;
4728        struct diff_queue_struct outq;
4729
4730        DIFF_QUEUE_CLEAR(&outq);
4731
4732        if (!options->filter)
4733                return;
4734
4735        if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
4736                int found;
4737                for (i = found = 0; !found && i < q->nr; i++) {
4738                        if (match_filter(options, q->queue[i]))
4739                                found++;
4740                }
4741                if (found)
4742                        return;
4743
4744                /* otherwise we will clear the whole queue
4745                 * by copying the empty outq at the end of this
4746                 * function, but first clear the current entries
4747                 * in the queue.
4748                 */
4749                for (i = 0; i < q->nr; i++)
4750                        diff_free_filepair(q->queue[i]);
4751        }
4752        else {
4753                /* Only the matching ones */
4754                for (i = 0; i < q->nr; i++) {
4755                        struct diff_filepair *p = q->queue[i];
4756                        if (match_filter(options, p))
4757                                diff_q(&outq, p);
4758                        else
4759                                diff_free_filepair(p);
4760                }
4761        }
4762        free(q->queue);
4763        *q = outq;
4764}
4765
4766/* Check whether two filespecs with the same mode and size are identical */
4767static int diff_filespec_is_identical(struct diff_filespec *one,
4768                                      struct diff_filespec *two)
4769{
4770        if (S_ISGITLINK(one->mode))
4771                return 0;
4772        if (diff_populate_filespec(one, 0))
4773                return 0;
4774        if (diff_populate_filespec(two, 0))
4775                return 0;
4776        return !memcmp(one->data, two->data, one->size);
4777}
4778
4779static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
4780{
4781        if (p->done_skip_stat_unmatch)
4782                return p->skip_stat_unmatch_result;
4783
4784        p->done_skip_stat_unmatch = 1;
4785        p->skip_stat_unmatch_result = 0;
4786        /*
4787         * 1. Entries that come from stat info dirtiness
4788         *    always have both sides (iow, not create/delete),
4789         *    one side of the object name is unknown, with
4790         *    the same mode and size.  Keep the ones that
4791         *    do not match these criteria.  They have real
4792         *    differences.
4793         *
4794         * 2. At this point, the file is known to be modified,
4795         *    with the same mode and size, and the object
4796         *    name of one side is unknown.  Need to inspect
4797         *    the identical contents.
4798         */
4799        if (!DIFF_FILE_VALID(p->one) || /* (1) */
4800            !DIFF_FILE_VALID(p->two) ||
4801            (p->one->sha1_valid && p->two->sha1_valid) ||
4802            (p->one->mode != p->two->mode) ||
4803            diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
4804            diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
4805            (p->one->size != p->two->size) ||
4806            !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4807                p->skip_stat_unmatch_result = 1;
4808        return p->skip_stat_unmatch_result;
4809}
4810
4811static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4812{
4813        int i;
4814        struct diff_queue_struct *q = &diff_queued_diff;
4815        struct diff_queue_struct outq;
4816        DIFF_QUEUE_CLEAR(&outq);
4817
4818        for (i = 0; i < q->nr; i++) {
4819                struct diff_filepair *p = q->queue[i];
4820
4821                if (diff_filespec_check_stat_unmatch(p))
4822                        diff_q(&outq, p);
4823                else {
4824                        /*
4825                         * The caller can subtract 1 from skip_stat_unmatch
4826                         * to determine how many paths were dirty only
4827                         * due to stat info mismatch.
4828                         */
4829                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4830                                diffopt->skip_stat_unmatch++;
4831                        diff_free_filepair(p);
4832                }
4833        }
4834        free(q->queue);
4835        *q = outq;
4836}
4837
4838static int diffnamecmp(const void *a_, const void *b_)
4839{
4840        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4841        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4842        const char *name_a, *name_b;
4843
4844        name_a = a->one ? a->one->path : a->two->path;
4845        name_b = b->one ? b->one->path : b->two->path;
4846        return strcmp(name_a, name_b);
4847}
4848
4849void diffcore_fix_diff_index(struct diff_options *options)
4850{
4851        struct diff_queue_struct *q = &diff_queued_diff;
4852        qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4853}
4854
4855void diffcore_std(struct diff_options *options)
4856{
4857        /* NOTE please keep the following in sync with diff_tree_combined() */
4858        if (options->skip_stat_unmatch)
4859                diffcore_skip_stat_unmatch(options);
4860        if (!options->found_follow) {
4861                /* See try_to_follow_renames() in tree-diff.c */
4862                if (options->break_opt != -1)
4863                        diffcore_break(options->break_opt);
4864                if (options->detect_rename)
4865                        diffcore_rename(options);
4866                if (options->break_opt != -1)
4867                        diffcore_merge_broken();
4868        }
4869        if (options->pickaxe)
4870                diffcore_pickaxe(options);
4871        if (options->orderfile)
4872                diffcore_order(options->orderfile);
4873        if (!options->found_follow)
4874                /* See try_to_follow_renames() in tree-diff.c */
4875                diff_resolve_rename_copy();
4876        diffcore_apply_filter(options);
4877
4878        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4879                DIFF_OPT_SET(options, HAS_CHANGES);
4880        else
4881                DIFF_OPT_CLR(options, HAS_CHANGES);
4882
4883        options->found_follow = 0;
4884}
4885
4886int diff_result_code(struct diff_options *opt, int status)
4887{
4888        int result = 0;
4889
4890        diff_warn_rename_limit("diff.renameLimit",
4891                               opt->needed_rename_limit,
4892                               opt->degraded_cc_to_c);
4893        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4894            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4895                return status;
4896        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4897            DIFF_OPT_TST(opt, HAS_CHANGES))
4898                result |= 01;
4899        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4900            DIFF_OPT_TST(opt, CHECK_FAILED))
4901                result |= 02;
4902        return result;
4903}
4904
4905int diff_can_quit_early(struct diff_options *opt)
4906{
4907        return (DIFF_OPT_TST(opt, QUICK) &&
4908                !opt->filter &&
4909                DIFF_OPT_TST(opt, HAS_CHANGES));
4910}
4911
4912/*
4913 * Shall changes to this submodule be ignored?
4914 *
4915 * Submodule changes can be configured to be ignored separately for each path,
4916 * but that configuration can be overridden from the command line.
4917 */
4918static int is_submodule_ignored(const char *path, struct diff_options *options)
4919{
4920        int ignored = 0;
4921        unsigned orig_flags = options->flags;
4922        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4923                set_diffopt_flags_from_submodule_config(options, path);
4924        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4925                ignored = 1;
4926        options->flags = orig_flags;
4927        return ignored;
4928}
4929
4930void diff_addremove(struct diff_options *options,
4931                    int addremove, unsigned mode,
4932                    const unsigned char *sha1,
4933                    int sha1_valid,
4934                    const char *concatpath, unsigned dirty_submodule)
4935{
4936        struct diff_filespec *one, *two;
4937
4938        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4939                return;
4940
4941        /* This may look odd, but it is a preparation for
4942         * feeding "there are unchanged files which should
4943         * not produce diffs, but when you are doing copy
4944         * detection you would need them, so here they are"
4945         * entries to the diff-core.  They will be prefixed
4946         * with something like '=' or '*' (I haven't decided
4947         * which but should not make any difference).
4948         * Feeding the same new and old to diff_change()
4949         * also has the same effect.
4950         * Before the final output happens, they are pruned after
4951         * merged into rename/copy pairs as appropriate.
4952         */
4953        if (DIFF_OPT_TST(options, REVERSE_DIFF))
4954                addremove = (addremove == '+' ? '-' :
4955                             addremove == '-' ? '+' : addremove);
4956
4957        if (options->prefix &&
4958            strncmp(concatpath, options->prefix, options->prefix_length))
4959                return;
4960
4961        one = alloc_filespec(concatpath);
4962        two = alloc_filespec(concatpath);
4963
4964        if (addremove != '+')
4965                fill_filespec(one, sha1, sha1_valid, mode);
4966        if (addremove != '-') {
4967                fill_filespec(two, sha1, sha1_valid, mode);
4968                two->dirty_submodule = dirty_submodule;
4969        }
4970
4971        diff_queue(&diff_queued_diff, one, two);
4972        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4973                DIFF_OPT_SET(options, HAS_CHANGES);
4974}
4975
4976void diff_change(struct diff_options *options,
4977                 unsigned old_mode, unsigned new_mode,
4978                 const unsigned char *old_sha1,
4979                 const unsigned char *new_sha1,
4980                 int old_sha1_valid, int new_sha1_valid,
4981                 const char *concatpath,
4982                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4983{
4984        struct diff_filespec *one, *two;
4985        struct diff_filepair *p;
4986
4987        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4988            is_submodule_ignored(concatpath, options))
4989                return;
4990
4991        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4992                unsigned tmp;
4993                const unsigned char *tmp_c;
4994                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
4995                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
4996                tmp = old_sha1_valid; old_sha1_valid = new_sha1_valid;
4997                        new_sha1_valid = tmp;
4998                tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
4999                        new_dirty_submodule = tmp;
5000        }
5001
5002        if (options->prefix &&
5003            strncmp(concatpath, options->prefix, options->prefix_length))
5004                return;
5005
5006        one = alloc_filespec(concatpath);
5007        two = alloc_filespec(concatpath);
5008        fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
5009        fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
5010        one->dirty_submodule = old_dirty_submodule;
5011        two->dirty_submodule = new_dirty_submodule;
5012        p = diff_queue(&diff_queued_diff, one, two);
5013
5014        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5015                return;
5016
5017        if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
5018            !diff_filespec_check_stat_unmatch(p))
5019                return;
5020
5021        DIFF_OPT_SET(options, HAS_CHANGES);
5022}
5023
5024struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
5025{
5026        struct diff_filepair *pair;
5027        struct diff_filespec *one, *two;
5028
5029        if (options->prefix &&
5030            strncmp(path, options->prefix, options->prefix_length))
5031                return NULL;
5032
5033        one = alloc_filespec(path);
5034        two = alloc_filespec(path);
5035        pair = diff_queue(&diff_queued_diff, one, two);
5036        pair->is_unmerged = 1;
5037        return pair;
5038}
5039
5040static char *run_textconv(const char *pgm, struct diff_filespec *spec,
5041                size_t *outsize)
5042{
5043        struct diff_tempfile *temp;
5044        const char *argv[3];
5045        const char **arg = argv;
5046        struct child_process child = CHILD_PROCESS_INIT;
5047        struct strbuf buf = STRBUF_INIT;
5048        int err = 0;
5049
5050        temp = prepare_temp_file(spec->path, spec);
5051        *arg++ = pgm;
5052        *arg++ = temp->name;
5053        *arg = NULL;
5054
5055        child.use_shell = 1;
5056        child.argv = argv;
5057        child.out = -1;
5058        if (start_command(&child)) {
5059                remove_tempfile();
5060                return NULL;
5061        }
5062
5063        if (strbuf_read(&buf, child.out, 0) < 0)
5064                err = error("error reading from textconv command '%s'", pgm);
5065        close(child.out);
5066
5067        if (finish_command(&child) || err) {
5068                strbuf_release(&buf);
5069                remove_tempfile();
5070                return NULL;
5071        }
5072        remove_tempfile();
5073
5074        return strbuf_detach(&buf, outsize);
5075}
5076
5077size_t fill_textconv(struct userdiff_driver *driver,
5078                     struct diff_filespec *df,
5079                     char **outbuf)
5080{
5081        size_t size;
5082
5083        if (!driver || !driver->textconv) {
5084                if (!DIFF_FILE_VALID(df)) {
5085                        *outbuf = "";
5086                        return 0;
5087                }
5088                if (diff_populate_filespec(df, 0))
5089                        die("unable to read files to diff");
5090                *outbuf = df->data;
5091                return df->size;
5092        }
5093
5094        if (driver->textconv_cache && df->sha1_valid) {
5095                *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
5096                                          &size);
5097                if (*outbuf)
5098                        return size;
5099        }
5100
5101        *outbuf = run_textconv(driver->textconv, df, &size);
5102        if (!*outbuf)
5103                die("unable to read files to diff");
5104
5105        if (driver->textconv_cache && df->sha1_valid) {
5106                /* ignore errors, as we might be in a readonly repository */
5107                notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
5108                                size);
5109                /*
5110                 * we could save up changes and flush them all at the end,
5111                 * but we would need an extra call after all diffing is done.
5112                 * Since generating a cache entry is the slow path anyway,
5113                 * this extra overhead probably isn't a big deal.
5114                 */
5115                notes_cache_write(driver->textconv_cache);
5116        }
5117
5118        return size;
5119}
5120
5121void setup_diff_pager(struct diff_options *opt)
5122{
5123        /*
5124         * If the user asked for our exit code, then either they want --quiet
5125         * or --exit-code. We should definitely not bother with a pager in the
5126         * former case, as we will generate no output. Since we still properly
5127         * report our exit code even when a pager is run, we _could_ run a
5128         * pager with --exit-code. But since we have not done so historically,
5129         * and because it is easy to find people oneline advising "git diff
5130         * --exit-code" in hooks and other scripts, we do not do so.
5131         */
5132        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5133            check_pager_config("diff") != 0)
5134                setup_pager();
5135}