diff.con commit Merge branch 'jc/perl-cat-blob' into maint (06d7abb)
   1/*
   2 * Copyright (C) 2005 Junio C Hamano
   3 */
   4#include "cache.h"
   5#include "quote.h"
   6#include "diff.h"
   7#include "diffcore.h"
   8#include "delta.h"
   9#include "xdiff-interface.h"
  10#include "color.h"
  11#include "attr.h"
  12#include "run-command.h"
  13#include "utf8.h"
  14#include "userdiff.h"
  15#include "sigchain.h"
  16#include "submodule.h"
  17#include "ll-merge.h"
  18#include "string-list.h"
  19
  20#ifdef NO_FAST_WORKING_DIRECTORY
  21#define FAST_WORKING_DIRECTORY 0
  22#else
  23#define FAST_WORKING_DIRECTORY 1
  24#endif
  25
  26static int diff_detect_rename_default;
  27static int diff_rename_limit_default = 400;
  28static int diff_suppress_blank_empty;
  29static int diff_use_color_default = -1;
  30static int diff_context_default = 3;
  31static const char *diff_word_regex_cfg;
  32static const char *external_diff_cmd_cfg;
  33int diff_auto_refresh_index = 1;
  34static int diff_mnemonic_prefix;
  35static int diff_no_prefix;
  36static int diff_stat_graph_width;
  37static int diff_dirstat_permille_default = 30;
  38static struct diff_options default_diff_options;
  39static long diff_algorithm;
  40
  41static char diff_colors[][COLOR_MAXLEN] = {
  42        GIT_COLOR_RESET,
  43        GIT_COLOR_NORMAL,       /* PLAIN */
  44        GIT_COLOR_BOLD,         /* METAINFO */
  45        GIT_COLOR_CYAN,         /* FRAGINFO */
  46        GIT_COLOR_RED,          /* OLD */
  47        GIT_COLOR_GREEN,        /* NEW */
  48        GIT_COLOR_YELLOW,       /* COMMIT */
  49        GIT_COLOR_BG_RED,       /* WHITESPACE */
  50        GIT_COLOR_NORMAL,       /* FUNCINFO */
  51};
  52
  53static int parse_diff_color_slot(const char *var, int ofs)
  54{
  55        if (!strcasecmp(var+ofs, "plain"))
  56                return DIFF_PLAIN;
  57        if (!strcasecmp(var+ofs, "meta"))
  58                return DIFF_METAINFO;
  59        if (!strcasecmp(var+ofs, "frag"))
  60                return DIFF_FRAGINFO;
  61        if (!strcasecmp(var+ofs, "old"))
  62                return DIFF_FILE_OLD;
  63        if (!strcasecmp(var+ofs, "new"))
  64                return DIFF_FILE_NEW;
  65        if (!strcasecmp(var+ofs, "commit"))
  66                return DIFF_COMMIT;
  67        if (!strcasecmp(var+ofs, "whitespace"))
  68                return DIFF_WHITESPACE;
  69        if (!strcasecmp(var+ofs, "func"))
  70                return DIFF_FUNCINFO;
  71        return -1;
  72}
  73
  74static int parse_dirstat_params(struct diff_options *options, const char *params_string,
  75                                struct strbuf *errmsg)
  76{
  77        char *params_copy = xstrdup(params_string);
  78        struct string_list params = STRING_LIST_INIT_NODUP;
  79        int ret = 0;
  80        int i;
  81
  82        if (*params_copy)
  83                string_list_split_in_place(&params, params_copy, ',', -1);
  84        for (i = 0; i < params.nr; i++) {
  85                const char *p = params.items[i].string;
  86                if (!strcmp(p, "changes")) {
  87                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  88                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  89                } else if (!strcmp(p, "lines")) {
  90                        DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
  91                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  92                } else if (!strcmp(p, "files")) {
  93                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  94                        DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
  95                } else if (!strcmp(p, "noncumulative")) {
  96                        DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
  97                } else if (!strcmp(p, "cumulative")) {
  98                        DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
  99                } else if (isdigit(*p)) {
 100                        char *end;
 101                        int permille = strtoul(p, &end, 10) * 10;
 102                        if (*end == '.' && isdigit(*++end)) {
 103                                /* only use first digit */
 104                                permille += *end - '0';
 105                                /* .. and ignore any further digits */
 106                                while (isdigit(*++end))
 107                                        ; /* nothing */
 108                        }
 109                        if (!*end)
 110                                options->dirstat_permille = permille;
 111                        else {
 112                                strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 113                                            p);
 114                                ret++;
 115                        }
 116                } else {
 117                        strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 118                        ret++;
 119                }
 120
 121        }
 122        string_list_clear(&params, 0);
 123        free(params_copy);
 124        return ret;
 125}
 126
 127static int parse_submodule_params(struct diff_options *options, const char *value)
 128{
 129        if (!strcmp(value, "log"))
 130                DIFF_OPT_SET(options, SUBMODULE_LOG);
 131        else if (!strcmp(value, "short"))
 132                DIFF_OPT_CLR(options, SUBMODULE_LOG);
 133        else
 134                return -1;
 135        return 0;
 136}
 137
 138static int git_config_rename(const char *var, const char *value)
 139{
 140        if (!value)
 141                return DIFF_DETECT_RENAME;
 142        if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 143                return  DIFF_DETECT_COPY;
 144        return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 145}
 146
 147long parse_algorithm_value(const char *value)
 148{
 149        if (!value)
 150                return -1;
 151        else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 152                return 0;
 153        else if (!strcasecmp(value, "minimal"))
 154                return XDF_NEED_MINIMAL;
 155        else if (!strcasecmp(value, "patience"))
 156                return XDF_PATIENCE_DIFF;
 157        else if (!strcasecmp(value, "histogram"))
 158                return XDF_HISTOGRAM_DIFF;
 159        return -1;
 160}
 161
 162/*
 163 * These are to give UI layer defaults.
 164 * The core-level commands such as git-diff-files should
 165 * never be affected by the setting of diff.renames
 166 * the user happens to have in the configuration file.
 167 */
 168int git_diff_ui_config(const char *var, const char *value, void *cb)
 169{
 170        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 171                diff_use_color_default = git_config_colorbool(var, value);
 172                return 0;
 173        }
 174        if (!strcmp(var, "diff.context")) {
 175                diff_context_default = git_config_int(var, value);
 176                if (diff_context_default < 0)
 177                        return -1;
 178                return 0;
 179        }
 180        if (!strcmp(var, "diff.renames")) {
 181                diff_detect_rename_default = git_config_rename(var, value);
 182                return 0;
 183        }
 184        if (!strcmp(var, "diff.autorefreshindex")) {
 185                diff_auto_refresh_index = git_config_bool(var, value);
 186                return 0;
 187        }
 188        if (!strcmp(var, "diff.mnemonicprefix")) {
 189                diff_mnemonic_prefix = git_config_bool(var, value);
 190                return 0;
 191        }
 192        if (!strcmp(var, "diff.noprefix")) {
 193                diff_no_prefix = git_config_bool(var, value);
 194                return 0;
 195        }
 196        if (!strcmp(var, "diff.statgraphwidth")) {
 197                diff_stat_graph_width = git_config_int(var, value);
 198                return 0;
 199        }
 200        if (!strcmp(var, "diff.external"))
 201                return git_config_string(&external_diff_cmd_cfg, var, value);
 202        if (!strcmp(var, "diff.wordregex"))
 203                return git_config_string(&diff_word_regex_cfg, var, value);
 204
 205        if (!strcmp(var, "diff.ignoresubmodules"))
 206                handle_ignore_submodules_arg(&default_diff_options, value);
 207
 208        if (!strcmp(var, "diff.submodule")) {
 209                if (parse_submodule_params(&default_diff_options, value))
 210                        warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 211                                value);
 212                return 0;
 213        }
 214
 215        if (!strcmp(var, "diff.algorithm")) {
 216                diff_algorithm = parse_algorithm_value(value);
 217                if (diff_algorithm < 0)
 218                        return -1;
 219                return 0;
 220        }
 221
 222        if (git_color_config(var, value, cb) < 0)
 223                return -1;
 224
 225        return git_diff_basic_config(var, value, cb);
 226}
 227
 228int git_diff_basic_config(const char *var, const char *value, void *cb)
 229{
 230        if (!strcmp(var, "diff.renamelimit")) {
 231                diff_rename_limit_default = git_config_int(var, value);
 232                return 0;
 233        }
 234
 235        if (userdiff_config(var, value) < 0)
 236                return -1;
 237
 238        if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
 239                int slot = parse_diff_color_slot(var, 11);
 240                if (slot < 0)
 241                        return 0;
 242                if (!value)
 243                        return config_error_nonbool(var);
 244                color_parse(value, var, diff_colors[slot]);
 245                return 0;
 246        }
 247
 248        /* like GNU diff's --suppress-blank-empty option  */
 249        if (!strcmp(var, "diff.suppressblankempty") ||
 250                        /* for backwards compatibility */
 251                        !strcmp(var, "diff.suppress-blank-empty")) {
 252                diff_suppress_blank_empty = git_config_bool(var, value);
 253                return 0;
 254        }
 255
 256        if (!strcmp(var, "diff.dirstat")) {
 257                struct strbuf errmsg = STRBUF_INIT;
 258                default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 259                if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 260                        warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 261                                errmsg.buf);
 262                strbuf_release(&errmsg);
 263                diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 264                return 0;
 265        }
 266
 267        if (!prefixcmp(var, "submodule."))
 268                return parse_submodule_config_option(var, value);
 269
 270        return git_default_config(var, value, cb);
 271}
 272
 273static char *quote_two(const char *one, const char *two)
 274{
 275        int need_one = quote_c_style(one, NULL, NULL, 1);
 276        int need_two = quote_c_style(two, NULL, NULL, 1);
 277        struct strbuf res = STRBUF_INIT;
 278
 279        if (need_one + need_two) {
 280                strbuf_addch(&res, '"');
 281                quote_c_style(one, &res, NULL, 1);
 282                quote_c_style(two, &res, NULL, 1);
 283                strbuf_addch(&res, '"');
 284        } else {
 285                strbuf_addstr(&res, one);
 286                strbuf_addstr(&res, two);
 287        }
 288        return strbuf_detach(&res, NULL);
 289}
 290
 291static const char *external_diff(void)
 292{
 293        static const char *external_diff_cmd = NULL;
 294        static int done_preparing = 0;
 295
 296        if (done_preparing)
 297                return external_diff_cmd;
 298        external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 299        if (!external_diff_cmd)
 300                external_diff_cmd = external_diff_cmd_cfg;
 301        done_preparing = 1;
 302        return external_diff_cmd;
 303}
 304
 305static struct diff_tempfile {
 306        const char *name; /* filename external diff should read from */
 307        char hex[41];
 308        char mode[10];
 309        char tmp_path[PATH_MAX];
 310} diff_temp[2];
 311
 312typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 313
 314struct emit_callback {
 315        int color_diff;
 316        unsigned ws_rule;
 317        int blank_at_eof_in_preimage;
 318        int blank_at_eof_in_postimage;
 319        int lno_in_preimage;
 320        int lno_in_postimage;
 321        sane_truncate_fn truncate;
 322        const char **label_path;
 323        struct diff_words_data *diff_words;
 324        struct diff_options *opt;
 325        int *found_changesp;
 326        struct strbuf *header;
 327};
 328
 329static int count_lines(const char *data, int size)
 330{
 331        int count, ch, completely_empty = 1, nl_just_seen = 0;
 332        count = 0;
 333        while (0 < size--) {
 334                ch = *data++;
 335                if (ch == '\n') {
 336                        count++;
 337                        nl_just_seen = 1;
 338                        completely_empty = 0;
 339                }
 340                else {
 341                        nl_just_seen = 0;
 342                        completely_empty = 0;
 343                }
 344        }
 345        if (completely_empty)
 346                return 0;
 347        if (!nl_just_seen)
 348                count++; /* no trailing newline */
 349        return count;
 350}
 351
 352static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 353{
 354        if (!DIFF_FILE_VALID(one)) {
 355                mf->ptr = (char *)""; /* does not matter */
 356                mf->size = 0;
 357                return 0;
 358        }
 359        else if (diff_populate_filespec(one, 0))
 360                return -1;
 361
 362        mf->ptr = one->data;
 363        mf->size = one->size;
 364        return 0;
 365}
 366
 367/* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 368static unsigned long diff_filespec_size(struct diff_filespec *one)
 369{
 370        if (!DIFF_FILE_VALID(one))
 371                return 0;
 372        diff_populate_filespec(one, 1);
 373        return one->size;
 374}
 375
 376static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 377{
 378        char *ptr = mf->ptr;
 379        long size = mf->size;
 380        int cnt = 0;
 381
 382        if (!size)
 383                return cnt;
 384        ptr += size - 1; /* pointing at the very end */
 385        if (*ptr != '\n')
 386                ; /* incomplete line */
 387        else
 388                ptr--; /* skip the last LF */
 389        while (mf->ptr < ptr) {
 390                char *prev_eol;
 391                for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 392                        if (*prev_eol == '\n')
 393                                break;
 394                if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 395                        break;
 396                cnt++;
 397                ptr = prev_eol - 1;
 398        }
 399        return cnt;
 400}
 401
 402static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 403                               struct emit_callback *ecbdata)
 404{
 405        int l1, l2, at;
 406        unsigned ws_rule = ecbdata->ws_rule;
 407        l1 = count_trailing_blank(mf1, ws_rule);
 408        l2 = count_trailing_blank(mf2, ws_rule);
 409        if (l2 <= l1) {
 410                ecbdata->blank_at_eof_in_preimage = 0;
 411                ecbdata->blank_at_eof_in_postimage = 0;
 412                return;
 413        }
 414        at = count_lines(mf1->ptr, mf1->size);
 415        ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 416
 417        at = count_lines(mf2->ptr, mf2->size);
 418        ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 419}
 420
 421static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 422                        int first, const char *line, int len)
 423{
 424        int has_trailing_newline, has_trailing_carriage_return;
 425        int nofirst;
 426        FILE *file = o->file;
 427
 428        fputs(diff_line_prefix(o), file);
 429
 430        if (len == 0) {
 431                has_trailing_newline = (first == '\n');
 432                has_trailing_carriage_return = (!has_trailing_newline &&
 433                                                (first == '\r'));
 434                nofirst = has_trailing_newline || has_trailing_carriage_return;
 435        } else {
 436                has_trailing_newline = (len > 0 && line[len-1] == '\n');
 437                if (has_trailing_newline)
 438                        len--;
 439                has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 440                if (has_trailing_carriage_return)
 441                        len--;
 442                nofirst = 0;
 443        }
 444
 445        if (len || !nofirst) {
 446                fputs(set, file);
 447                if (!nofirst)
 448                        fputc(first, file);
 449                fwrite(line, len, 1, file);
 450                fputs(reset, file);
 451        }
 452        if (has_trailing_carriage_return)
 453                fputc('\r', file);
 454        if (has_trailing_newline)
 455                fputc('\n', file);
 456}
 457
 458static void emit_line(struct diff_options *o, const char *set, const char *reset,
 459                      const char *line, int len)
 460{
 461        emit_line_0(o, set, reset, line[0], line+1, len-1);
 462}
 463
 464static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 465{
 466        if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 467              ecbdata->blank_at_eof_in_preimage &&
 468              ecbdata->blank_at_eof_in_postimage &&
 469              ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 470              ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 471                return 0;
 472        return ws_blank_line(line, len, ecbdata->ws_rule);
 473}
 474
 475static void emit_add_line(const char *reset,
 476                          struct emit_callback *ecbdata,
 477                          const char *line, int len)
 478{
 479        const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 480        const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 481
 482        if (!*ws)
 483                emit_line_0(ecbdata->opt, set, reset, '+', line, len);
 484        else if (new_blank_line_at_eof(ecbdata, line, len))
 485                /* Blank line at EOF - paint '+' as well */
 486                emit_line_0(ecbdata->opt, ws, reset, '+', line, len);
 487        else {
 488                /* Emit just the prefix, then the rest. */
 489                emit_line_0(ecbdata->opt, set, reset, '+', "", 0);
 490                ws_check_emit(line, len, ecbdata->ws_rule,
 491                              ecbdata->opt->file, set, reset, ws);
 492        }
 493}
 494
 495static void emit_hunk_header(struct emit_callback *ecbdata,
 496                             const char *line, int len)
 497{
 498        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
 499        const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 500        const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 501        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 502        static const char atat[2] = { '@', '@' };
 503        const char *cp, *ep;
 504        struct strbuf msgbuf = STRBUF_INIT;
 505        int org_len = len;
 506        int i = 1;
 507
 508        /*
 509         * As a hunk header must begin with "@@ -<old>, +<new> @@",
 510         * it always is at least 10 bytes long.
 511         */
 512        if (len < 10 ||
 513            memcmp(line, atat, 2) ||
 514            !(ep = memmem(line + 2, len - 2, atat, 2))) {
 515                emit_line(ecbdata->opt, plain, reset, line, len);
 516                return;
 517        }
 518        ep += 2; /* skip over @@ */
 519
 520        /* The hunk header in fraginfo color */
 521        strbuf_add(&msgbuf, frag, strlen(frag));
 522        strbuf_add(&msgbuf, line, ep - line);
 523        strbuf_add(&msgbuf, reset, strlen(reset));
 524
 525        /*
 526         * trailing "\r\n"
 527         */
 528        for ( ; i < 3; i++)
 529                if (line[len - i] == '\r' || line[len - i] == '\n')
 530                        len--;
 531
 532        /* blank before the func header */
 533        for (cp = ep; ep - line < len; ep++)
 534                if (*ep != ' ' && *ep != '\t')
 535                        break;
 536        if (ep != cp) {
 537                strbuf_add(&msgbuf, plain, strlen(plain));
 538                strbuf_add(&msgbuf, cp, ep - cp);
 539                strbuf_add(&msgbuf, reset, strlen(reset));
 540        }
 541
 542        if (ep < line + len) {
 543                strbuf_add(&msgbuf, func, strlen(func));
 544                strbuf_add(&msgbuf, ep, line + len - ep);
 545                strbuf_add(&msgbuf, reset, strlen(reset));
 546        }
 547
 548        strbuf_add(&msgbuf, line + len, org_len - len);
 549        emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 550        strbuf_release(&msgbuf);
 551}
 552
 553static struct diff_tempfile *claim_diff_tempfile(void) {
 554        int i;
 555        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 556                if (!diff_temp[i].name)
 557                        return diff_temp + i;
 558        die("BUG: diff is failing to clean up its tempfiles");
 559}
 560
 561static int remove_tempfile_installed;
 562
 563static void remove_tempfile(void)
 564{
 565        int i;
 566        for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 567                if (diff_temp[i].name == diff_temp[i].tmp_path)
 568                        unlink_or_warn(diff_temp[i].name);
 569                diff_temp[i].name = NULL;
 570        }
 571}
 572
 573static void remove_tempfile_on_signal(int signo)
 574{
 575        remove_tempfile();
 576        sigchain_pop(signo);
 577        raise(signo);
 578}
 579
 580static void print_line_count(FILE *file, int count)
 581{
 582        switch (count) {
 583        case 0:
 584                fprintf(file, "0,0");
 585                break;
 586        case 1:
 587                fprintf(file, "1");
 588                break;
 589        default:
 590                fprintf(file, "1,%d", count);
 591                break;
 592        }
 593}
 594
 595static void emit_rewrite_lines(struct emit_callback *ecb,
 596                               int prefix, const char *data, int size)
 597{
 598        const char *endp = NULL;
 599        static const char *nneof = " No newline at end of file\n";
 600        const char *old = diff_get_color(ecb->color_diff, DIFF_FILE_OLD);
 601        const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 602
 603        while (0 < size) {
 604                int len;
 605
 606                endp = memchr(data, '\n', size);
 607                len = endp ? (endp - data + 1) : size;
 608                if (prefix != '+') {
 609                        ecb->lno_in_preimage++;
 610                        emit_line_0(ecb->opt, old, reset, '-',
 611                                    data, len);
 612                } else {
 613                        ecb->lno_in_postimage++;
 614                        emit_add_line(reset, ecb, data, len);
 615                }
 616                size -= len;
 617                data += len;
 618        }
 619        if (!endp) {
 620                const char *plain = diff_get_color(ecb->color_diff,
 621                                                   DIFF_PLAIN);
 622                putc('\n', ecb->opt->file);
 623                emit_line_0(ecb->opt, plain, reset, '\\',
 624                            nneof, strlen(nneof));
 625        }
 626}
 627
 628static void emit_rewrite_diff(const char *name_a,
 629                              const char *name_b,
 630                              struct diff_filespec *one,
 631                              struct diff_filespec *two,
 632                              struct userdiff_driver *textconv_one,
 633                              struct userdiff_driver *textconv_two,
 634                              struct diff_options *o)
 635{
 636        int lc_a, lc_b;
 637        const char *name_a_tab, *name_b_tab;
 638        const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 639        const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 640        const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 641        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 642        const char *a_prefix, *b_prefix;
 643        char *data_one, *data_two;
 644        size_t size_one, size_two;
 645        struct emit_callback ecbdata;
 646        const char *line_prefix = diff_line_prefix(o);
 647
 648        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 649                a_prefix = o->b_prefix;
 650                b_prefix = o->a_prefix;
 651        } else {
 652                a_prefix = o->a_prefix;
 653                b_prefix = o->b_prefix;
 654        }
 655
 656        name_a += (*name_a == '/');
 657        name_b += (*name_b == '/');
 658        name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 659        name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 660
 661        strbuf_reset(&a_name);
 662        strbuf_reset(&b_name);
 663        quote_two_c_style(&a_name, a_prefix, name_a, 0);
 664        quote_two_c_style(&b_name, b_prefix, name_b, 0);
 665
 666        size_one = fill_textconv(textconv_one, one, &data_one);
 667        size_two = fill_textconv(textconv_two, two, &data_two);
 668
 669        memset(&ecbdata, 0, sizeof(ecbdata));
 670        ecbdata.color_diff = want_color(o->use_color);
 671        ecbdata.found_changesp = &o->found_changes;
 672        ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
 673        ecbdata.opt = o;
 674        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 675                mmfile_t mf1, mf2;
 676                mf1.ptr = (char *)data_one;
 677                mf2.ptr = (char *)data_two;
 678                mf1.size = size_one;
 679                mf2.size = size_two;
 680                check_blank_at_eof(&mf1, &mf2, &ecbdata);
 681        }
 682        ecbdata.lno_in_preimage = 1;
 683        ecbdata.lno_in_postimage = 1;
 684
 685        lc_a = count_lines(data_one, size_one);
 686        lc_b = count_lines(data_two, size_two);
 687        fprintf(o->file,
 688                "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 689                line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 690                line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 691                line_prefix, fraginfo);
 692        if (!o->irreversible_delete)
 693                print_line_count(o->file, lc_a);
 694        else
 695                fprintf(o->file, "?,?");
 696        fprintf(o->file, " +");
 697        print_line_count(o->file, lc_b);
 698        fprintf(o->file, " @@%s\n", reset);
 699        if (lc_a && !o->irreversible_delete)
 700                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 701        if (lc_b)
 702                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 703        if (textconv_one)
 704                free((char *)data_one);
 705        if (textconv_two)
 706                free((char *)data_two);
 707}
 708
 709struct diff_words_buffer {
 710        mmfile_t text;
 711        long alloc;
 712        struct diff_words_orig {
 713                const char *begin, *end;
 714        } *orig;
 715        int orig_nr, orig_alloc;
 716};
 717
 718static void diff_words_append(char *line, unsigned long len,
 719                struct diff_words_buffer *buffer)
 720{
 721        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 722        line++;
 723        len--;
 724        memcpy(buffer->text.ptr + buffer->text.size, line, len);
 725        buffer->text.size += len;
 726        buffer->text.ptr[buffer->text.size] = '\0';
 727}
 728
 729struct diff_words_style_elem {
 730        const char *prefix;
 731        const char *suffix;
 732        const char *color; /* NULL; filled in by the setup code if
 733                            * color is enabled */
 734};
 735
 736struct diff_words_style {
 737        enum diff_words_type type;
 738        struct diff_words_style_elem new, old, ctx;
 739        const char *newline;
 740};
 741
 742static struct diff_words_style diff_words_styles[] = {
 743        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 744        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 745        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 746};
 747
 748struct diff_words_data {
 749        struct diff_words_buffer minus, plus;
 750        const char *current_plus;
 751        int last_minus;
 752        struct diff_options *opt;
 753        regex_t *word_regex;
 754        enum diff_words_type type;
 755        struct diff_words_style *style;
 756};
 757
 758static int fn_out_diff_words_write_helper(FILE *fp,
 759                                          struct diff_words_style_elem *st_el,
 760                                          const char *newline,
 761                                          size_t count, const char *buf,
 762                                          const char *line_prefix)
 763{
 764        int print = 0;
 765
 766        while (count) {
 767                char *p = memchr(buf, '\n', count);
 768                if (print)
 769                        fputs(line_prefix, fp);
 770                if (p != buf) {
 771                        if (st_el->color && fputs(st_el->color, fp) < 0)
 772                                return -1;
 773                        if (fputs(st_el->prefix, fp) < 0 ||
 774                            fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 775                            fputs(st_el->suffix, fp) < 0)
 776                                return -1;
 777                        if (st_el->color && *st_el->color
 778                            && fputs(GIT_COLOR_RESET, fp) < 0)
 779                                return -1;
 780                }
 781                if (!p)
 782                        return 0;
 783                if (fputs(newline, fp) < 0)
 784                        return -1;
 785                count -= p + 1 - buf;
 786                buf = p + 1;
 787                print = 1;
 788        }
 789        return 0;
 790}
 791
 792/*
 793 * '--color-words' algorithm can be described as:
 794 *
 795 *   1. collect a the minus/plus lines of a diff hunk, divided into
 796 *      minus-lines and plus-lines;
 797 *
 798 *   2. break both minus-lines and plus-lines into words and
 799 *      place them into two mmfile_t with one word for each line;
 800 *
 801 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 802 *
 803 * And for the common parts of the both file, we output the plus side text.
 804 * diff_words->current_plus is used to trace the current position of the plus file
 805 * which printed. diff_words->last_minus is used to trace the last minus word
 806 * printed.
 807 *
 808 * For '--graph' to work with '--color-words', we need to output the graph prefix
 809 * on each line of color words output. Generally, there are two conditions on
 810 * which we should output the prefix.
 811 *
 812 *   1. diff_words->last_minus == 0 &&
 813 *      diff_words->current_plus == diff_words->plus.text.ptr
 814 *
 815 *      that is: the plus text must start as a new line, and if there is no minus
 816 *      word printed, a graph prefix must be printed.
 817 *
 818 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 819 *      *(diff_words->current_plus - 1) == '\n'
 820 *
 821 *      that is: a graph prefix must be printed following a '\n'
 822 */
 823static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 824{
 825        if ((diff_words->last_minus == 0 &&
 826                diff_words->current_plus == diff_words->plus.text.ptr) ||
 827                (diff_words->current_plus > diff_words->plus.text.ptr &&
 828                *(diff_words->current_plus - 1) == '\n')) {
 829                return 1;
 830        } else {
 831                return 0;
 832        }
 833}
 834
 835static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 836{
 837        struct diff_words_data *diff_words = priv;
 838        struct diff_words_style *style = diff_words->style;
 839        int minus_first, minus_len, plus_first, plus_len;
 840        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 841        struct diff_options *opt = diff_words->opt;
 842        const char *line_prefix;
 843
 844        if (line[0] != '@' || parse_hunk_header(line, len,
 845                        &minus_first, &minus_len, &plus_first, &plus_len))
 846                return;
 847
 848        assert(opt);
 849        line_prefix = diff_line_prefix(opt);
 850
 851        /* POSIX requires that first be decremented by one if len == 0... */
 852        if (minus_len) {
 853                minus_begin = diff_words->minus.orig[minus_first].begin;
 854                minus_end =
 855                        diff_words->minus.orig[minus_first + minus_len - 1].end;
 856        } else
 857                minus_begin = minus_end =
 858                        diff_words->minus.orig[minus_first].end;
 859
 860        if (plus_len) {
 861                plus_begin = diff_words->plus.orig[plus_first].begin;
 862                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 863        } else
 864                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 865
 866        if (color_words_output_graph_prefix(diff_words)) {
 867                fputs(line_prefix, diff_words->opt->file);
 868        }
 869        if (diff_words->current_plus != plus_begin) {
 870                fn_out_diff_words_write_helper(diff_words->opt->file,
 871                                &style->ctx, style->newline,
 872                                plus_begin - diff_words->current_plus,
 873                                diff_words->current_plus, line_prefix);
 874                if (*(plus_begin - 1) == '\n')
 875                        fputs(line_prefix, diff_words->opt->file);
 876        }
 877        if (minus_begin != minus_end) {
 878                fn_out_diff_words_write_helper(diff_words->opt->file,
 879                                &style->old, style->newline,
 880                                minus_end - minus_begin, minus_begin,
 881                                line_prefix);
 882        }
 883        if (plus_begin != plus_end) {
 884                fn_out_diff_words_write_helper(diff_words->opt->file,
 885                                &style->new, style->newline,
 886                                plus_end - plus_begin, plus_begin,
 887                                line_prefix);
 888        }
 889
 890        diff_words->current_plus = plus_end;
 891        diff_words->last_minus = minus_first;
 892}
 893
 894/* This function starts looking at *begin, and returns 0 iff a word was found. */
 895static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 896                int *begin, int *end)
 897{
 898        if (word_regex && *begin < buffer->size) {
 899                regmatch_t match[1];
 900                if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 901                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 902                                        '\n', match[0].rm_eo - match[0].rm_so);
 903                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 904                        *begin += match[0].rm_so;
 905                        return *begin >= *end;
 906                }
 907                return -1;
 908        }
 909
 910        /* find the next word */
 911        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 912                (*begin)++;
 913        if (*begin >= buffer->size)
 914                return -1;
 915
 916        /* find the end of the word */
 917        *end = *begin + 1;
 918        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 919                (*end)++;
 920
 921        return 0;
 922}
 923
 924/*
 925 * This function splits the words in buffer->text, stores the list with
 926 * newline separator into out, and saves the offsets of the original words
 927 * in buffer->orig.
 928 */
 929static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 930                regex_t *word_regex)
 931{
 932        int i, j;
 933        long alloc = 0;
 934
 935        out->size = 0;
 936        out->ptr = NULL;
 937
 938        /* fake an empty "0th" word */
 939        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 940        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 941        buffer->orig_nr = 1;
 942
 943        for (i = 0; i < buffer->text.size; i++) {
 944                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 945                        return;
 946
 947                /* store original boundaries */
 948                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
 949                                buffer->orig_alloc);
 950                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
 951                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
 952                buffer->orig_nr++;
 953
 954                /* store one word */
 955                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
 956                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
 957                out->ptr[out->size + j - i] = '\n';
 958                out->size += j - i + 1;
 959
 960                i = j - 1;
 961        }
 962}
 963
 964/* this executes the word diff on the accumulated buffers */
 965static void diff_words_show(struct diff_words_data *diff_words)
 966{
 967        xpparam_t xpp;
 968        xdemitconf_t xecfg;
 969        mmfile_t minus, plus;
 970        struct diff_words_style *style = diff_words->style;
 971
 972        struct diff_options *opt = diff_words->opt;
 973        const char *line_prefix;
 974
 975        assert(opt);
 976        line_prefix = diff_line_prefix(opt);
 977
 978        /* special case: only removal */
 979        if (!diff_words->plus.text.size) {
 980                fputs(line_prefix, diff_words->opt->file);
 981                fn_out_diff_words_write_helper(diff_words->opt->file,
 982                        &style->old, style->newline,
 983                        diff_words->minus.text.size,
 984                        diff_words->minus.text.ptr, line_prefix);
 985                diff_words->minus.text.size = 0;
 986                return;
 987        }
 988
 989        diff_words->current_plus = diff_words->plus.text.ptr;
 990        diff_words->last_minus = 0;
 991
 992        memset(&xpp, 0, sizeof(xpp));
 993        memset(&xecfg, 0, sizeof(xecfg));
 994        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
 995        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
 996        xpp.flags = 0;
 997        /* as only the hunk header will be parsed, we need a 0-context */
 998        xecfg.ctxlen = 0;
 999        xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1000                      &xpp, &xecfg);
1001        free(minus.ptr);
1002        free(plus.ptr);
1003        if (diff_words->current_plus != diff_words->plus.text.ptr +
1004                        diff_words->plus.text.size) {
1005                if (color_words_output_graph_prefix(diff_words))
1006                        fputs(line_prefix, diff_words->opt->file);
1007                fn_out_diff_words_write_helper(diff_words->opt->file,
1008                        &style->ctx, style->newline,
1009                        diff_words->plus.text.ptr + diff_words->plus.text.size
1010                        - diff_words->current_plus, diff_words->current_plus,
1011                        line_prefix);
1012        }
1013        diff_words->minus.text.size = diff_words->plus.text.size = 0;
1014}
1015
1016/* In "color-words" mode, show word-diff of words accumulated in the buffer */
1017static void diff_words_flush(struct emit_callback *ecbdata)
1018{
1019        if (ecbdata->diff_words->minus.text.size ||
1020            ecbdata->diff_words->plus.text.size)
1021                diff_words_show(ecbdata->diff_words);
1022}
1023
1024static void diff_filespec_load_driver(struct diff_filespec *one)
1025{
1026        /* Use already-loaded driver */
1027        if (one->driver)
1028                return;
1029
1030        if (S_ISREG(one->mode))
1031                one->driver = userdiff_find_by_path(one->path);
1032
1033        /* Fallback to default settings */
1034        if (!one->driver)
1035                one->driver = userdiff_find_by_name("default");
1036}
1037
1038static const char *userdiff_word_regex(struct diff_filespec *one)
1039{
1040        diff_filespec_load_driver(one);
1041        return one->driver->word_regex;
1042}
1043
1044static void init_diff_words_data(struct emit_callback *ecbdata,
1045                                 struct diff_options *orig_opts,
1046                                 struct diff_filespec *one,
1047                                 struct diff_filespec *two)
1048{
1049        int i;
1050        struct diff_options *o = xmalloc(sizeof(struct diff_options));
1051        memcpy(o, orig_opts, sizeof(struct diff_options));
1052
1053        ecbdata->diff_words =
1054                xcalloc(1, sizeof(struct diff_words_data));
1055        ecbdata->diff_words->type = o->word_diff;
1056        ecbdata->diff_words->opt = o;
1057        if (!o->word_regex)
1058                o->word_regex = userdiff_word_regex(one);
1059        if (!o->word_regex)
1060                o->word_regex = userdiff_word_regex(two);
1061        if (!o->word_regex)
1062                o->word_regex = diff_word_regex_cfg;
1063        if (o->word_regex) {
1064                ecbdata->diff_words->word_regex = (regex_t *)
1065                        xmalloc(sizeof(regex_t));
1066                if (regcomp(ecbdata->diff_words->word_regex,
1067                            o->word_regex,
1068                            REG_EXTENDED | REG_NEWLINE))
1069                        die ("Invalid regular expression: %s",
1070                             o->word_regex);
1071        }
1072        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1073                if (o->word_diff == diff_words_styles[i].type) {
1074                        ecbdata->diff_words->style =
1075                                &diff_words_styles[i];
1076                        break;
1077                }
1078        }
1079        if (want_color(o->use_color)) {
1080                struct diff_words_style *st = ecbdata->diff_words->style;
1081                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1082                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1083                st->ctx.color = diff_get_color_opt(o, DIFF_PLAIN);
1084        }
1085}
1086
1087static void free_diff_words_data(struct emit_callback *ecbdata)
1088{
1089        if (ecbdata->diff_words) {
1090                diff_words_flush(ecbdata);
1091                free (ecbdata->diff_words->opt);
1092                free (ecbdata->diff_words->minus.text.ptr);
1093                free (ecbdata->diff_words->minus.orig);
1094                free (ecbdata->diff_words->plus.text.ptr);
1095                free (ecbdata->diff_words->plus.orig);
1096                if (ecbdata->diff_words->word_regex) {
1097                        regfree(ecbdata->diff_words->word_regex);
1098                        free(ecbdata->diff_words->word_regex);
1099                }
1100                free(ecbdata->diff_words);
1101                ecbdata->diff_words = NULL;
1102        }
1103}
1104
1105const char *diff_get_color(int diff_use_color, enum color_diff ix)
1106{
1107        if (want_color(diff_use_color))
1108                return diff_colors[ix];
1109        return "";
1110}
1111
1112const char *diff_line_prefix(struct diff_options *opt)
1113{
1114        struct strbuf *msgbuf;
1115        if (!opt->output_prefix)
1116                return "";
1117
1118        msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1119        return msgbuf->buf;
1120}
1121
1122static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1123{
1124        const char *cp;
1125        unsigned long allot;
1126        size_t l = len;
1127
1128        if (ecb->truncate)
1129                return ecb->truncate(line, len);
1130        cp = line;
1131        allot = l;
1132        while (0 < l) {
1133                (void) utf8_width(&cp, &l);
1134                if (!cp)
1135                        break; /* truncated in the middle? */
1136        }
1137        return allot - l;
1138}
1139
1140static void find_lno(const char *line, struct emit_callback *ecbdata)
1141{
1142        const char *p;
1143        ecbdata->lno_in_preimage = 0;
1144        ecbdata->lno_in_postimage = 0;
1145        p = strchr(line, '-');
1146        if (!p)
1147                return; /* cannot happen */
1148        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1149        p = strchr(p, '+');
1150        if (!p)
1151                return; /* cannot happen */
1152        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1153}
1154
1155static void fn_out_consume(void *priv, char *line, unsigned long len)
1156{
1157        struct emit_callback *ecbdata = priv;
1158        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1159        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
1160        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1161        struct diff_options *o = ecbdata->opt;
1162        const char *line_prefix = diff_line_prefix(o);
1163
1164        if (ecbdata->header) {
1165                fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1166                strbuf_reset(ecbdata->header);
1167                ecbdata->header = NULL;
1168        }
1169        *(ecbdata->found_changesp) = 1;
1170
1171        if (ecbdata->label_path[0]) {
1172                const char *name_a_tab, *name_b_tab;
1173
1174                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1175                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1176
1177                fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1178                        line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1179                fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1180                        line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1181                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1182        }
1183
1184        if (diff_suppress_blank_empty
1185            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1186                line[0] = '\n';
1187                len = 1;
1188        }
1189
1190        if (line[0] == '@') {
1191                if (ecbdata->diff_words)
1192                        diff_words_flush(ecbdata);
1193                len = sane_truncate_line(ecbdata, line, len);
1194                find_lno(line, ecbdata);
1195                emit_hunk_header(ecbdata, line, len);
1196                if (line[len-1] != '\n')
1197                        putc('\n', ecbdata->opt->file);
1198                return;
1199        }
1200
1201        if (len < 1) {
1202                emit_line(ecbdata->opt, reset, reset, line, len);
1203                if (ecbdata->diff_words
1204                    && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1205                        fputs("~\n", ecbdata->opt->file);
1206                return;
1207        }
1208
1209        if (ecbdata->diff_words) {
1210                if (line[0] == '-') {
1211                        diff_words_append(line, len,
1212                                          &ecbdata->diff_words->minus);
1213                        return;
1214                } else if (line[0] == '+') {
1215                        diff_words_append(line, len,
1216                                          &ecbdata->diff_words->plus);
1217                        return;
1218                } else if (!prefixcmp(line, "\\ ")) {
1219                        /*
1220                         * Eat the "no newline at eof" marker as if we
1221                         * saw a "+" or "-" line with nothing on it,
1222                         * and return without diff_words_flush() to
1223                         * defer processing. If this is the end of
1224                         * preimage, more "+" lines may come after it.
1225                         */
1226                        return;
1227                }
1228                diff_words_flush(ecbdata);
1229                if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1230                        emit_line(ecbdata->opt, plain, reset, line, len);
1231                        fputs("~\n", ecbdata->opt->file);
1232                } else {
1233                        /*
1234                         * Skip the prefix character, if any.  With
1235                         * diff_suppress_blank_empty, there may be
1236                         * none.
1237                         */
1238                        if (line[0] != '\n') {
1239                              line++;
1240                              len--;
1241                        }
1242                        emit_line(ecbdata->opt, plain, reset, line, len);
1243                }
1244                return;
1245        }
1246
1247        if (line[0] != '+') {
1248                const char *color =
1249                        diff_get_color(ecbdata->color_diff,
1250                                       line[0] == '-' ? DIFF_FILE_OLD : DIFF_PLAIN);
1251                ecbdata->lno_in_preimage++;
1252                if (line[0] == ' ')
1253                        ecbdata->lno_in_postimage++;
1254                emit_line(ecbdata->opt, color, reset, line, len);
1255        } else {
1256                ecbdata->lno_in_postimage++;
1257                emit_add_line(reset, ecbdata, line + 1, len - 1);
1258        }
1259}
1260
1261static char *pprint_rename(const char *a, const char *b)
1262{
1263        const char *old = a;
1264        const char *new = b;
1265        struct strbuf name = STRBUF_INIT;
1266        int pfx_length, sfx_length;
1267        int len_a = strlen(a);
1268        int len_b = strlen(b);
1269        int a_midlen, b_midlen;
1270        int qlen_a = quote_c_style(a, NULL, NULL, 0);
1271        int qlen_b = quote_c_style(b, NULL, NULL, 0);
1272
1273        if (qlen_a || qlen_b) {
1274                quote_c_style(a, &name, NULL, 0);
1275                strbuf_addstr(&name, " => ");
1276                quote_c_style(b, &name, NULL, 0);
1277                return strbuf_detach(&name, NULL);
1278        }
1279
1280        /* Find common prefix */
1281        pfx_length = 0;
1282        while (*old && *new && *old == *new) {
1283                if (*old == '/')
1284                        pfx_length = old - a + 1;
1285                old++;
1286                new++;
1287        }
1288
1289        /* Find common suffix */
1290        old = a + len_a;
1291        new = b + len_b;
1292        sfx_length = 0;
1293        while (a <= old && b <= new && *old == *new) {
1294                if (*old == '/')
1295                        sfx_length = len_a - (old - a);
1296                old--;
1297                new--;
1298        }
1299
1300        /*
1301         * pfx{mid-a => mid-b}sfx
1302         * {pfx-a => pfx-b}sfx
1303         * pfx{sfx-a => sfx-b}
1304         * name-a => name-b
1305         */
1306        a_midlen = len_a - pfx_length - sfx_length;
1307        b_midlen = len_b - pfx_length - sfx_length;
1308        if (a_midlen < 0)
1309                a_midlen = 0;
1310        if (b_midlen < 0)
1311                b_midlen = 0;
1312
1313        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1314        if (pfx_length + sfx_length) {
1315                strbuf_add(&name, a, pfx_length);
1316                strbuf_addch(&name, '{');
1317        }
1318        strbuf_add(&name, a + pfx_length, a_midlen);
1319        strbuf_addstr(&name, " => ");
1320        strbuf_add(&name, b + pfx_length, b_midlen);
1321        if (pfx_length + sfx_length) {
1322                strbuf_addch(&name, '}');
1323                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1324        }
1325        return strbuf_detach(&name, NULL);
1326}
1327
1328struct diffstat_t {
1329        int nr;
1330        int alloc;
1331        struct diffstat_file {
1332                char *from_name;
1333                char *name;
1334                char *print_name;
1335                unsigned is_unmerged:1;
1336                unsigned is_binary:1;
1337                unsigned is_renamed:1;
1338                unsigned is_interesting:1;
1339                uintmax_t added, deleted;
1340        } **files;
1341};
1342
1343static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1344                                          const char *name_a,
1345                                          const char *name_b)
1346{
1347        struct diffstat_file *x;
1348        x = xcalloc(sizeof (*x), 1);
1349        if (diffstat->nr == diffstat->alloc) {
1350                diffstat->alloc = alloc_nr(diffstat->alloc);
1351                diffstat->files = xrealloc(diffstat->files,
1352                                diffstat->alloc * sizeof(x));
1353        }
1354        diffstat->files[diffstat->nr++] = x;
1355        if (name_b) {
1356                x->from_name = xstrdup(name_a);
1357                x->name = xstrdup(name_b);
1358                x->is_renamed = 1;
1359        }
1360        else {
1361                x->from_name = NULL;
1362                x->name = xstrdup(name_a);
1363        }
1364        return x;
1365}
1366
1367static void diffstat_consume(void *priv, char *line, unsigned long len)
1368{
1369        struct diffstat_t *diffstat = priv;
1370        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1371
1372        if (line[0] == '+')
1373                x->added++;
1374        else if (line[0] == '-')
1375                x->deleted++;
1376}
1377
1378const char mime_boundary_leader[] = "------------";
1379
1380static int scale_linear(int it, int width, int max_change)
1381{
1382        if (!it)
1383                return 0;
1384        /*
1385         * make sure that at least one '-' or '+' is printed if
1386         * there is any change to this path. The easiest way is to
1387         * scale linearly as if the alloted width is one column shorter
1388         * than it is, and then add 1 to the result.
1389         */
1390        return 1 + (it * (width - 1) / max_change);
1391}
1392
1393static void show_name(FILE *file,
1394                      const char *prefix, const char *name, int len)
1395{
1396        fprintf(file, " %s%-*s |", prefix, len, name);
1397}
1398
1399static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1400{
1401        if (cnt <= 0)
1402                return;
1403        fprintf(file, "%s", set);
1404        while (cnt--)
1405                putc(ch, file);
1406        fprintf(file, "%s", reset);
1407}
1408
1409static void fill_print_name(struct diffstat_file *file)
1410{
1411        char *pname;
1412
1413        if (file->print_name)
1414                return;
1415
1416        if (!file->is_renamed) {
1417                struct strbuf buf = STRBUF_INIT;
1418                if (quote_c_style(file->name, &buf, NULL, 0)) {
1419                        pname = strbuf_detach(&buf, NULL);
1420                } else {
1421                        pname = file->name;
1422                        strbuf_release(&buf);
1423                }
1424        } else {
1425                pname = pprint_rename(file->from_name, file->name);
1426        }
1427        file->print_name = pname;
1428}
1429
1430int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1431{
1432        struct strbuf sb = STRBUF_INIT;
1433        int ret;
1434
1435        if (!files) {
1436                assert(insertions == 0 && deletions == 0);
1437                return fprintf(fp, "%s\n", " 0 files changed");
1438        }
1439
1440        strbuf_addf(&sb,
1441                    (files == 1) ? " %d file changed" : " %d files changed",
1442                    files);
1443
1444        /*
1445         * For binary diff, the caller may want to print "x files
1446         * changed" with insertions == 0 && deletions == 0.
1447         *
1448         * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1449         * is probably less confusing (i.e skip over "2 files changed
1450         * but nothing about added/removed lines? Is this a bug in Git?").
1451         */
1452        if (insertions || deletions == 0) {
1453                /*
1454                 * TRANSLATORS: "+" in (+) is a line addition marker;
1455                 * do not translate it.
1456                 */
1457                strbuf_addf(&sb,
1458                            (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1459                            insertions);
1460        }
1461
1462        if (deletions || insertions == 0) {
1463                /*
1464                 * TRANSLATORS: "-" in (-) is a line removal marker;
1465                 * do not translate it.
1466                 */
1467                strbuf_addf(&sb,
1468                            (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1469                            deletions);
1470        }
1471        strbuf_addch(&sb, '\n');
1472        ret = fputs(sb.buf, fp);
1473        strbuf_release(&sb);
1474        return ret;
1475}
1476
1477static void show_stats(struct diffstat_t *data, struct diff_options *options)
1478{
1479        int i, len, add, del, adds = 0, dels = 0;
1480        uintmax_t max_change = 0, max_len = 0;
1481        int total_files = data->nr, count;
1482        int width, name_width, graph_width, number_width = 0, bin_width = 0;
1483        const char *reset, *add_c, *del_c;
1484        const char *line_prefix = "";
1485        int extra_shown = 0;
1486
1487        if (data->nr == 0)
1488                return;
1489
1490        line_prefix = diff_line_prefix(options);
1491        count = options->stat_count ? options->stat_count : data->nr;
1492
1493        reset = diff_get_color_opt(options, DIFF_RESET);
1494        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1495        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1496
1497        /*
1498         * Find the longest filename and max number of changes
1499         */
1500        for (i = 0; (i < count) && (i < data->nr); i++) {
1501                struct diffstat_file *file = data->files[i];
1502                uintmax_t change = file->added + file->deleted;
1503
1504                if (!file->is_interesting && (change == 0)) {
1505                        count++; /* not shown == room for one more */
1506                        continue;
1507                }
1508                fill_print_name(file);
1509                len = strlen(file->print_name);
1510                if (max_len < len)
1511                        max_len = len;
1512
1513                if (file->is_unmerged) {
1514                        /* "Unmerged" is 8 characters */
1515                        bin_width = bin_width < 8 ? 8 : bin_width;
1516                        continue;
1517                }
1518                if (file->is_binary) {
1519                        /* "Bin XXX -> YYY bytes" */
1520                        int w = 14 + decimal_width(file->added)
1521                                + decimal_width(file->deleted);
1522                        bin_width = bin_width < w ? w : bin_width;
1523                        /* Display change counts aligned with "Bin" */
1524                        number_width = 3;
1525                        continue;
1526                }
1527
1528                if (max_change < change)
1529                        max_change = change;
1530        }
1531        count = i; /* where we can stop scanning in data->files[] */
1532
1533        /*
1534         * We have width = stat_width or term_columns() columns total.
1535         * We want a maximum of min(max_len, stat_name_width) for the name part.
1536         * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1537         * We also need 1 for " " and 4 + decimal_width(max_change)
1538         * for " | NNNN " and one the empty column at the end, altogether
1539         * 6 + decimal_width(max_change).
1540         *
1541         * If there's not enough space, we will use the smaller of
1542         * stat_name_width (if set) and 5/8*width for the filename,
1543         * and the rest for constant elements + graph part, but no more
1544         * than stat_graph_width for the graph part.
1545         * (5/8 gives 50 for filename and 30 for the constant parts + graph
1546         * for the standard terminal size).
1547         *
1548         * In other words: stat_width limits the maximum width, and
1549         * stat_name_width fixes the maximum width of the filename,
1550         * and is also used to divide available columns if there
1551         * aren't enough.
1552         *
1553         * Binary files are displayed with "Bin XXX -> YYY bytes"
1554         * instead of the change count and graph. This part is treated
1555         * similarly to the graph part, except that it is not
1556         * "scaled". If total width is too small to accomodate the
1557         * guaranteed minimum width of the filename part and the
1558         * separators and this message, this message will "overflow"
1559         * making the line longer than the maximum width.
1560         */
1561
1562        if (options->stat_width == -1)
1563                width = term_columns() - options->output_prefix_length;
1564        else
1565                width = options->stat_width ? options->stat_width : 80;
1566        number_width = decimal_width(max_change) > number_width ?
1567                decimal_width(max_change) : number_width;
1568
1569        if (options->stat_graph_width == -1)
1570                options->stat_graph_width = diff_stat_graph_width;
1571
1572        /*
1573         * Guarantee 3/8*16==6 for the graph part
1574         * and 5/8*16==10 for the filename part
1575         */
1576        if (width < 16 + 6 + number_width)
1577                width = 16 + 6 + number_width;
1578
1579        /*
1580         * First assign sizes that are wanted, ignoring available width.
1581         * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1582         * starting from "XXX" should fit in graph_width.
1583         */
1584        graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1585        if (options->stat_graph_width &&
1586            options->stat_graph_width < graph_width)
1587                graph_width = options->stat_graph_width;
1588
1589        name_width = (options->stat_name_width > 0 &&
1590                      options->stat_name_width < max_len) ?
1591                options->stat_name_width : max_len;
1592
1593        /*
1594         * Adjust adjustable widths not to exceed maximum width
1595         */
1596        if (name_width + number_width + 6 + graph_width > width) {
1597                if (graph_width > width * 3/8 - number_width - 6) {
1598                        graph_width = width * 3/8 - number_width - 6;
1599                        if (graph_width < 6)
1600                                graph_width = 6;
1601                }
1602
1603                if (options->stat_graph_width &&
1604                    graph_width > options->stat_graph_width)
1605                        graph_width = options->stat_graph_width;
1606                if (name_width > width - number_width - 6 - graph_width)
1607                        name_width = width - number_width - 6 - graph_width;
1608                else
1609                        graph_width = width - number_width - 6 - name_width;
1610        }
1611
1612        /*
1613         * From here name_width is the width of the name area,
1614         * and graph_width is the width of the graph area.
1615         * max_change is used to scale graph properly.
1616         */
1617        for (i = 0; i < count; i++) {
1618                const char *prefix = "";
1619                struct diffstat_file *file = data->files[i];
1620                char *name = file->print_name;
1621                uintmax_t added = file->added;
1622                uintmax_t deleted = file->deleted;
1623                int name_len;
1624
1625                if (!file->is_interesting && (added + deleted == 0))
1626                        continue;
1627
1628                /*
1629                 * "scale" the filename
1630                 */
1631                len = name_width;
1632                name_len = strlen(name);
1633                if (name_width < name_len) {
1634                        char *slash;
1635                        prefix = "...";
1636                        len -= 3;
1637                        name += name_len - len;
1638                        slash = strchr(name, '/');
1639                        if (slash)
1640                                name = slash;
1641                }
1642
1643                if (file->is_binary) {
1644                        fprintf(options->file, "%s", line_prefix);
1645                        show_name(options->file, prefix, name, len);
1646                        fprintf(options->file, " %*s", number_width, "Bin");
1647                        if (!added && !deleted) {
1648                                putc('\n', options->file);
1649                                continue;
1650                        }
1651                        fprintf(options->file, " %s%"PRIuMAX"%s",
1652                                del_c, deleted, reset);
1653                        fprintf(options->file, " -> ");
1654                        fprintf(options->file, "%s%"PRIuMAX"%s",
1655                                add_c, added, reset);
1656                        fprintf(options->file, " bytes");
1657                        fprintf(options->file, "\n");
1658                        continue;
1659                }
1660                else if (file->is_unmerged) {
1661                        fprintf(options->file, "%s", line_prefix);
1662                        show_name(options->file, prefix, name, len);
1663                        fprintf(options->file, " Unmerged\n");
1664                        continue;
1665                }
1666
1667                /*
1668                 * scale the add/delete
1669                 */
1670                add = added;
1671                del = deleted;
1672
1673                if (graph_width <= max_change) {
1674                        int total = add + del;
1675
1676                        total = scale_linear(add + del, graph_width, max_change);
1677                        if (total < 2 && add && del)
1678                                /* width >= 2 due to the sanity check */
1679                                total = 2;
1680                        if (add < del) {
1681                                add = scale_linear(add, graph_width, max_change);
1682                                del = total - add;
1683                        } else {
1684                                del = scale_linear(del, graph_width, max_change);
1685                                add = total - del;
1686                        }
1687                }
1688                fprintf(options->file, "%s", line_prefix);
1689                show_name(options->file, prefix, name, len);
1690                fprintf(options->file, " %*"PRIuMAX"%s",
1691                        number_width, added + deleted,
1692                        added + deleted ? " " : "");
1693                show_graph(options->file, '+', add, add_c, reset);
1694                show_graph(options->file, '-', del, del_c, reset);
1695                fprintf(options->file, "\n");
1696        }
1697
1698        for (i = 0; i < data->nr; i++) {
1699                struct diffstat_file *file = data->files[i];
1700                uintmax_t added = file->added;
1701                uintmax_t deleted = file->deleted;
1702
1703                if (file->is_unmerged ||
1704                    (!file->is_interesting && (added + deleted == 0))) {
1705                        total_files--;
1706                        continue;
1707                }
1708
1709                if (!file->is_binary) {
1710                        adds += added;
1711                        dels += deleted;
1712                }
1713                if (i < count)
1714                        continue;
1715                if (!extra_shown)
1716                        fprintf(options->file, "%s ...\n", line_prefix);
1717                extra_shown = 1;
1718        }
1719        fprintf(options->file, "%s", line_prefix);
1720        print_stat_summary(options->file, total_files, adds, dels);
1721}
1722
1723static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1724{
1725        int i, adds = 0, dels = 0, total_files = data->nr;
1726
1727        if (data->nr == 0)
1728                return;
1729
1730        for (i = 0; i < data->nr; i++) {
1731                int added = data->files[i]->added;
1732                int deleted= data->files[i]->deleted;
1733
1734                if (data->files[i]->is_unmerged ||
1735                    (!data->files[i]->is_interesting && (added + deleted == 0))) {
1736                        total_files--;
1737                } else if (!data->files[i]->is_binary) { /* don't count bytes */
1738                        adds += added;
1739                        dels += deleted;
1740                }
1741        }
1742        fprintf(options->file, "%s", diff_line_prefix(options));
1743        print_stat_summary(options->file, total_files, adds, dels);
1744}
1745
1746static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1747{
1748        int i;
1749
1750        if (data->nr == 0)
1751                return;
1752
1753        for (i = 0; i < data->nr; i++) {
1754                struct diffstat_file *file = data->files[i];
1755
1756                fprintf(options->file, "%s", diff_line_prefix(options));
1757
1758                if (file->is_binary)
1759                        fprintf(options->file, "-\t-\t");
1760                else
1761                        fprintf(options->file,
1762                                "%"PRIuMAX"\t%"PRIuMAX"\t",
1763                                file->added, file->deleted);
1764                if (options->line_termination) {
1765                        fill_print_name(file);
1766                        if (!file->is_renamed)
1767                                write_name_quoted(file->name, options->file,
1768                                                  options->line_termination);
1769                        else {
1770                                fputs(file->print_name, options->file);
1771                                putc(options->line_termination, options->file);
1772                        }
1773                } else {
1774                        if (file->is_renamed) {
1775                                putc('\0', options->file);
1776                                write_name_quoted(file->from_name, options->file, '\0');
1777                        }
1778                        write_name_quoted(file->name, options->file, '\0');
1779                }
1780        }
1781}
1782
1783struct dirstat_file {
1784        const char *name;
1785        unsigned long changed;
1786};
1787
1788struct dirstat_dir {
1789        struct dirstat_file *files;
1790        int alloc, nr, permille, cumulative;
1791};
1792
1793static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1794                unsigned long changed, const char *base, int baselen)
1795{
1796        unsigned long this_dir = 0;
1797        unsigned int sources = 0;
1798        const char *line_prefix = diff_line_prefix(opt);
1799
1800        while (dir->nr) {
1801                struct dirstat_file *f = dir->files;
1802                int namelen = strlen(f->name);
1803                unsigned long this;
1804                char *slash;
1805
1806                if (namelen < baselen)
1807                        break;
1808                if (memcmp(f->name, base, baselen))
1809                        break;
1810                slash = strchr(f->name + baselen, '/');
1811                if (slash) {
1812                        int newbaselen = slash + 1 - f->name;
1813                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1814                        sources++;
1815                } else {
1816                        this = f->changed;
1817                        dir->files++;
1818                        dir->nr--;
1819                        sources += 2;
1820                }
1821                this_dir += this;
1822        }
1823
1824        /*
1825         * We don't report dirstat's for
1826         *  - the top level
1827         *  - or cases where everything came from a single directory
1828         *    under this directory (sources == 1).
1829         */
1830        if (baselen && sources != 1) {
1831                if (this_dir) {
1832                        int permille = this_dir * 1000 / changed;
1833                        if (permille >= dir->permille) {
1834                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1835                                        permille / 10, permille % 10, baselen, base);
1836                                if (!dir->cumulative)
1837                                        return 0;
1838                        }
1839                }
1840        }
1841        return this_dir;
1842}
1843
1844static int dirstat_compare(const void *_a, const void *_b)
1845{
1846        const struct dirstat_file *a = _a;
1847        const struct dirstat_file *b = _b;
1848        return strcmp(a->name, b->name);
1849}
1850
1851static void show_dirstat(struct diff_options *options)
1852{
1853        int i;
1854        unsigned long changed;
1855        struct dirstat_dir dir;
1856        struct diff_queue_struct *q = &diff_queued_diff;
1857
1858        dir.files = NULL;
1859        dir.alloc = 0;
1860        dir.nr = 0;
1861        dir.permille = options->dirstat_permille;
1862        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1863
1864        changed = 0;
1865        for (i = 0; i < q->nr; i++) {
1866                struct diff_filepair *p = q->queue[i];
1867                const char *name;
1868                unsigned long copied, added, damage;
1869                int content_changed;
1870
1871                name = p->two->path ? p->two->path : p->one->path;
1872
1873                if (p->one->sha1_valid && p->two->sha1_valid)
1874                        content_changed = hashcmp(p->one->sha1, p->two->sha1);
1875                else
1876                        content_changed = 1;
1877
1878                if (!content_changed) {
1879                        /*
1880                         * The SHA1 has not changed, so pre-/post-content is
1881                         * identical. We can therefore skip looking at the
1882                         * file contents altogether.
1883                         */
1884                        damage = 0;
1885                        goto found_damage;
1886                }
1887
1888                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1889                        /*
1890                         * In --dirstat-by-file mode, we don't really need to
1891                         * look at the actual file contents at all.
1892                         * The fact that the SHA1 changed is enough for us to
1893                         * add this file to the list of results
1894                         * (with each file contributing equal damage).
1895                         */
1896                        damage = 1;
1897                        goto found_damage;
1898                }
1899
1900                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1901                        diff_populate_filespec(p->one, 0);
1902                        diff_populate_filespec(p->two, 0);
1903                        diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1904                                               &copied, &added);
1905                        diff_free_filespec_data(p->one);
1906                        diff_free_filespec_data(p->two);
1907                } else if (DIFF_FILE_VALID(p->one)) {
1908                        diff_populate_filespec(p->one, 1);
1909                        copied = added = 0;
1910                        diff_free_filespec_data(p->one);
1911                } else if (DIFF_FILE_VALID(p->two)) {
1912                        diff_populate_filespec(p->two, 1);
1913                        copied = 0;
1914                        added = p->two->size;
1915                        diff_free_filespec_data(p->two);
1916                } else
1917                        continue;
1918
1919                /*
1920                 * Original minus copied is the removed material,
1921                 * added is the new material.  They are both damages
1922                 * made to the preimage.
1923                 * If the resulting damage is zero, we know that
1924                 * diffcore_count_changes() considers the two entries to
1925                 * be identical, but since content_changed is true, we
1926                 * know that there must have been _some_ kind of change,
1927                 * so we force all entries to have damage > 0.
1928                 */
1929                damage = (p->one->size - copied) + added;
1930                if (!damage)
1931                        damage = 1;
1932
1933found_damage:
1934                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1935                dir.files[dir.nr].name = name;
1936                dir.files[dir.nr].changed = damage;
1937                changed += damage;
1938                dir.nr++;
1939        }
1940
1941        /* This can happen even with many files, if everything was renames */
1942        if (!changed)
1943                return;
1944
1945        /* Show all directories with more than x% of the changes */
1946        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1947        gather_dirstat(options, &dir, changed, "", 0);
1948}
1949
1950static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
1951{
1952        int i;
1953        unsigned long changed;
1954        struct dirstat_dir dir;
1955
1956        if (data->nr == 0)
1957                return;
1958
1959        dir.files = NULL;
1960        dir.alloc = 0;
1961        dir.nr = 0;
1962        dir.permille = options->dirstat_permille;
1963        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1964
1965        changed = 0;
1966        for (i = 0; i < data->nr; i++) {
1967                struct diffstat_file *file = data->files[i];
1968                unsigned long damage = file->added + file->deleted;
1969                if (file->is_binary)
1970                        /*
1971                         * binary files counts bytes, not lines. Must find some
1972                         * way to normalize binary bytes vs. textual lines.
1973                         * The following heuristic assumes that there are 64
1974                         * bytes per "line".
1975                         * This is stupid and ugly, but very cheap...
1976                         */
1977                        damage = (damage + 63) / 64;
1978                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1979                dir.files[dir.nr].name = file->name;
1980                dir.files[dir.nr].changed = damage;
1981                changed += damage;
1982                dir.nr++;
1983        }
1984
1985        /* This can happen even with many files, if everything was renames */
1986        if (!changed)
1987                return;
1988
1989        /* Show all directories with more than x% of the changes */
1990        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1991        gather_dirstat(options, &dir, changed, "", 0);
1992}
1993
1994static void free_diffstat_info(struct diffstat_t *diffstat)
1995{
1996        int i;
1997        for (i = 0; i < diffstat->nr; i++) {
1998                struct diffstat_file *f = diffstat->files[i];
1999                if (f->name != f->print_name)
2000                        free(f->print_name);
2001                free(f->name);
2002                free(f->from_name);
2003                free(f);
2004        }
2005        free(diffstat->files);
2006}
2007
2008struct checkdiff_t {
2009        const char *filename;
2010        int lineno;
2011        int conflict_marker_size;
2012        struct diff_options *o;
2013        unsigned ws_rule;
2014        unsigned status;
2015};
2016
2017static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2018{
2019        char firstchar;
2020        int cnt;
2021
2022        if (len < marker_size + 1)
2023                return 0;
2024        firstchar = line[0];
2025        switch (firstchar) {
2026        case '=': case '>': case '<': case '|':
2027                break;
2028        default:
2029                return 0;
2030        }
2031        for (cnt = 1; cnt < marker_size; cnt++)
2032                if (line[cnt] != firstchar)
2033                        return 0;
2034        /* line[1] thru line[marker_size-1] are same as firstchar */
2035        if (len < marker_size + 1 || !isspace(line[marker_size]))
2036                return 0;
2037        return 1;
2038}
2039
2040static void checkdiff_consume(void *priv, char *line, unsigned long len)
2041{
2042        struct checkdiff_t *data = priv;
2043        int marker_size = data->conflict_marker_size;
2044        const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2045        const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2046        const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2047        char *err;
2048        const char *line_prefix;
2049
2050        assert(data->o);
2051        line_prefix = diff_line_prefix(data->o);
2052
2053        if (line[0] == '+') {
2054                unsigned bad;
2055                data->lineno++;
2056                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2057                        data->status |= 1;
2058                        fprintf(data->o->file,
2059                                "%s%s:%d: leftover conflict marker\n",
2060                                line_prefix, data->filename, data->lineno);
2061                }
2062                bad = ws_check(line + 1, len - 1, data->ws_rule);
2063                if (!bad)
2064                        return;
2065                data->status |= bad;
2066                err = whitespace_error_string(bad);
2067                fprintf(data->o->file, "%s%s:%d: %s.\n",
2068                        line_prefix, data->filename, data->lineno, err);
2069                free(err);
2070                emit_line(data->o, set, reset, line, 1);
2071                ws_check_emit(line + 1, len - 1, data->ws_rule,
2072                              data->o->file, set, reset, ws);
2073        } else if (line[0] == ' ') {
2074                data->lineno++;
2075        } else if (line[0] == '@') {
2076                char *plus = strchr(line, '+');
2077                if (plus)
2078                        data->lineno = strtol(plus, NULL, 10) - 1;
2079                else
2080                        die("invalid diff");
2081        }
2082}
2083
2084static unsigned char *deflate_it(char *data,
2085                                 unsigned long size,
2086                                 unsigned long *result_size)
2087{
2088        int bound;
2089        unsigned char *deflated;
2090        git_zstream stream;
2091
2092        memset(&stream, 0, sizeof(stream));
2093        git_deflate_init(&stream, zlib_compression_level);
2094        bound = git_deflate_bound(&stream, size);
2095        deflated = xmalloc(bound);
2096        stream.next_out = deflated;
2097        stream.avail_out = bound;
2098
2099        stream.next_in = (unsigned char *)data;
2100        stream.avail_in = size;
2101        while (git_deflate(&stream, Z_FINISH) == Z_OK)
2102                ; /* nothing */
2103        git_deflate_end(&stream);
2104        *result_size = stream.total_out;
2105        return deflated;
2106}
2107
2108static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2109                                  const char *prefix)
2110{
2111        void *cp;
2112        void *delta;
2113        void *deflated;
2114        void *data;
2115        unsigned long orig_size;
2116        unsigned long delta_size;
2117        unsigned long deflate_size;
2118        unsigned long data_size;
2119
2120        /* We could do deflated delta, or we could do just deflated two,
2121         * whichever is smaller.
2122         */
2123        delta = NULL;
2124        deflated = deflate_it(two->ptr, two->size, &deflate_size);
2125        if (one->size && two->size) {
2126                delta = diff_delta(one->ptr, one->size,
2127                                   two->ptr, two->size,
2128                                   &delta_size, deflate_size);
2129                if (delta) {
2130                        void *to_free = delta;
2131                        orig_size = delta_size;
2132                        delta = deflate_it(delta, delta_size, &delta_size);
2133                        free(to_free);
2134                }
2135        }
2136
2137        if (delta && delta_size < deflate_size) {
2138                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2139                free(deflated);
2140                data = delta;
2141                data_size = delta_size;
2142        }
2143        else {
2144                fprintf(file, "%sliteral %lu\n", prefix, two->size);
2145                free(delta);
2146                data = deflated;
2147                data_size = deflate_size;
2148        }
2149
2150        /* emit data encoded in base85 */
2151        cp = data;
2152        while (data_size) {
2153                int bytes = (52 < data_size) ? 52 : data_size;
2154                char line[70];
2155                data_size -= bytes;
2156                if (bytes <= 26)
2157                        line[0] = bytes + 'A' - 1;
2158                else
2159                        line[0] = bytes - 26 + 'a' - 1;
2160                encode_85(line + 1, cp, bytes);
2161                cp = (char *) cp + bytes;
2162                fprintf(file, "%s", prefix);
2163                fputs(line, file);
2164                fputc('\n', file);
2165        }
2166        fprintf(file, "%s\n", prefix);
2167        free(data);
2168}
2169
2170static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2171                             const char *prefix)
2172{
2173        fprintf(file, "%sGIT binary patch\n", prefix);
2174        emit_binary_diff_body(file, one, two, prefix);
2175        emit_binary_diff_body(file, two, one, prefix);
2176}
2177
2178int diff_filespec_is_binary(struct diff_filespec *one)
2179{
2180        if (one->is_binary == -1) {
2181                diff_filespec_load_driver(one);
2182                if (one->driver->binary != -1)
2183                        one->is_binary = one->driver->binary;
2184                else {
2185                        if (!one->data && DIFF_FILE_VALID(one))
2186                                diff_populate_filespec(one, 0);
2187                        if (one->data)
2188                                one->is_binary = buffer_is_binary(one->data,
2189                                                one->size);
2190                        if (one->is_binary == -1)
2191                                one->is_binary = 0;
2192                }
2193        }
2194        return one->is_binary;
2195}
2196
2197static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2198{
2199        diff_filespec_load_driver(one);
2200        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2201}
2202
2203void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2204{
2205        if (!options->a_prefix)
2206                options->a_prefix = a;
2207        if (!options->b_prefix)
2208                options->b_prefix = b;
2209}
2210
2211struct userdiff_driver *get_textconv(struct diff_filespec *one)
2212{
2213        if (!DIFF_FILE_VALID(one))
2214                return NULL;
2215
2216        diff_filespec_load_driver(one);
2217        return userdiff_get_textconv(one->driver);
2218}
2219
2220static void builtin_diff(const char *name_a,
2221                         const char *name_b,
2222                         struct diff_filespec *one,
2223                         struct diff_filespec *two,
2224                         const char *xfrm_msg,
2225                         int must_show_header,
2226                         struct diff_options *o,
2227                         int complete_rewrite)
2228{
2229        mmfile_t mf1, mf2;
2230        const char *lbl[2];
2231        char *a_one, *b_two;
2232        const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2233        const char *reset = diff_get_color_opt(o, DIFF_RESET);
2234        const char *a_prefix, *b_prefix;
2235        struct userdiff_driver *textconv_one = NULL;
2236        struct userdiff_driver *textconv_two = NULL;
2237        struct strbuf header = STRBUF_INIT;
2238        const char *line_prefix = diff_line_prefix(o);
2239
2240        if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2241                        (!one->mode || S_ISGITLINK(one->mode)) &&
2242                        (!two->mode || S_ISGITLINK(two->mode))) {
2243                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2244                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2245                show_submodule_summary(o->file, one ? one->path : two->path,
2246                                one->sha1, two->sha1, two->dirty_submodule,
2247                                meta, del, add, reset);
2248                return;
2249        }
2250
2251        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2252                textconv_one = get_textconv(one);
2253                textconv_two = get_textconv(two);
2254        }
2255
2256        diff_set_mnemonic_prefix(o, "a/", "b/");
2257        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2258                a_prefix = o->b_prefix;
2259                b_prefix = o->a_prefix;
2260        } else {
2261                a_prefix = o->a_prefix;
2262                b_prefix = o->b_prefix;
2263        }
2264
2265        /* Never use a non-valid filename anywhere if at all possible */
2266        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2267        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2268
2269        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2270        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2271        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2272        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2273        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2274        if (lbl[0][0] == '/') {
2275                /* /dev/null */
2276                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2277                if (xfrm_msg)
2278                        strbuf_addstr(&header, xfrm_msg);
2279                must_show_header = 1;
2280        }
2281        else if (lbl[1][0] == '/') {
2282                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2283                if (xfrm_msg)
2284                        strbuf_addstr(&header, xfrm_msg);
2285                must_show_header = 1;
2286        }
2287        else {
2288                if (one->mode != two->mode) {
2289                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2290                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2291                        must_show_header = 1;
2292                }
2293                if (xfrm_msg)
2294                        strbuf_addstr(&header, xfrm_msg);
2295
2296                /*
2297                 * we do not run diff between different kind
2298                 * of objects.
2299                 */
2300                if ((one->mode ^ two->mode) & S_IFMT)
2301                        goto free_ab_and_return;
2302                if (complete_rewrite &&
2303                    (textconv_one || !diff_filespec_is_binary(one)) &&
2304                    (textconv_two || !diff_filespec_is_binary(two))) {
2305                        fprintf(o->file, "%s", header.buf);
2306                        strbuf_reset(&header);
2307                        emit_rewrite_diff(name_a, name_b, one, two,
2308                                                textconv_one, textconv_two, o);
2309                        o->found_changes = 1;
2310                        goto free_ab_and_return;
2311                }
2312        }
2313
2314        if (o->irreversible_delete && lbl[1][0] == '/') {
2315                fprintf(o->file, "%s", header.buf);
2316                strbuf_reset(&header);
2317                goto free_ab_and_return;
2318        } else if (!DIFF_OPT_TST(o, TEXT) &&
2319            ( (!textconv_one && diff_filespec_is_binary(one)) ||
2320              (!textconv_two && diff_filespec_is_binary(two)) )) {
2321                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2322                        die("unable to read files to diff");
2323                /* Quite common confusing case */
2324                if (mf1.size == mf2.size &&
2325                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2326                        if (must_show_header)
2327                                fprintf(o->file, "%s", header.buf);
2328                        goto free_ab_and_return;
2329                }
2330                fprintf(o->file, "%s", header.buf);
2331                strbuf_reset(&header);
2332                if (DIFF_OPT_TST(o, BINARY))
2333                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2334                else
2335                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2336                                line_prefix, lbl[0], lbl[1]);
2337                o->found_changes = 1;
2338        } else {
2339                /* Crazy xdl interfaces.. */
2340                const char *diffopts = getenv("GIT_DIFF_OPTS");
2341                xpparam_t xpp;
2342                xdemitconf_t xecfg;
2343                struct emit_callback ecbdata;
2344                const struct userdiff_funcname *pe;
2345
2346                if (must_show_header) {
2347                        fprintf(o->file, "%s", header.buf);
2348                        strbuf_reset(&header);
2349                }
2350
2351                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2352                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2353
2354                pe = diff_funcname_pattern(one);
2355                if (!pe)
2356                        pe = diff_funcname_pattern(two);
2357
2358                memset(&xpp, 0, sizeof(xpp));
2359                memset(&xecfg, 0, sizeof(xecfg));
2360                memset(&ecbdata, 0, sizeof(ecbdata));
2361                ecbdata.label_path = lbl;
2362                ecbdata.color_diff = want_color(o->use_color);
2363                ecbdata.found_changesp = &o->found_changes;
2364                ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
2365                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2366                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2367                ecbdata.opt = o;
2368                ecbdata.header = header.len ? &header : NULL;
2369                xpp.flags = o->xdl_opts;
2370                xecfg.ctxlen = o->context;
2371                xecfg.interhunkctxlen = o->interhunkcontext;
2372                xecfg.flags = XDL_EMIT_FUNCNAMES;
2373                if (DIFF_OPT_TST(o, FUNCCONTEXT))
2374                        xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2375                if (pe)
2376                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2377                if (!diffopts)
2378                        ;
2379                else if (!prefixcmp(diffopts, "--unified="))
2380                        xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
2381                else if (!prefixcmp(diffopts, "-u"))
2382                        xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
2383                if (o->word_diff)
2384                        init_diff_words_data(&ecbdata, o, one, two);
2385                xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2386                              &xpp, &xecfg);
2387                if (o->word_diff)
2388                        free_diff_words_data(&ecbdata);
2389                if (textconv_one)
2390                        free(mf1.ptr);
2391                if (textconv_two)
2392                        free(mf2.ptr);
2393                xdiff_clear_find_func(&xecfg);
2394        }
2395
2396 free_ab_and_return:
2397        strbuf_release(&header);
2398        diff_free_filespec_data(one);
2399        diff_free_filespec_data(two);
2400        free(a_one);
2401        free(b_two);
2402        return;
2403}
2404
2405static void builtin_diffstat(const char *name_a, const char *name_b,
2406                             struct diff_filespec *one,
2407                             struct diff_filespec *two,
2408                             struct diffstat_t *diffstat,
2409                             struct diff_options *o,
2410                             struct diff_filepair *p)
2411{
2412        mmfile_t mf1, mf2;
2413        struct diffstat_file *data;
2414        int same_contents;
2415        int complete_rewrite = 0;
2416
2417        if (!DIFF_PAIR_UNMERGED(p)) {
2418                if (p->status == DIFF_STATUS_MODIFIED && p->score)
2419                        complete_rewrite = 1;
2420        }
2421
2422        data = diffstat_add(diffstat, name_a, name_b);
2423        data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2424
2425        if (!one || !two) {
2426                data->is_unmerged = 1;
2427                return;
2428        }
2429
2430        same_contents = !hashcmp(one->sha1, two->sha1);
2431
2432        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2433                data->is_binary = 1;
2434                if (same_contents) {
2435                        data->added = 0;
2436                        data->deleted = 0;
2437                } else {
2438                        data->added = diff_filespec_size(two);
2439                        data->deleted = diff_filespec_size(one);
2440                }
2441        }
2442
2443        else if (complete_rewrite) {
2444                diff_populate_filespec(one, 0);
2445                diff_populate_filespec(two, 0);
2446                data->deleted = count_lines(one->data, one->size);
2447                data->added = count_lines(two->data, two->size);
2448        }
2449
2450        else if (!same_contents) {
2451                /* Crazy xdl interfaces.. */
2452                xpparam_t xpp;
2453                xdemitconf_t xecfg;
2454
2455                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2456                        die("unable to read files to diff");
2457
2458                memset(&xpp, 0, sizeof(xpp));
2459                memset(&xecfg, 0, sizeof(xecfg));
2460                xpp.flags = o->xdl_opts;
2461                xecfg.ctxlen = o->context;
2462                xecfg.interhunkctxlen = o->interhunkcontext;
2463                xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2464                              &xpp, &xecfg);
2465        }
2466
2467        diff_free_filespec_data(one);
2468        diff_free_filespec_data(two);
2469}
2470
2471static void builtin_checkdiff(const char *name_a, const char *name_b,
2472                              const char *attr_path,
2473                              struct diff_filespec *one,
2474                              struct diff_filespec *two,
2475                              struct diff_options *o)
2476{
2477        mmfile_t mf1, mf2;
2478        struct checkdiff_t data;
2479
2480        if (!two)
2481                return;
2482
2483        memset(&data, 0, sizeof(data));
2484        data.filename = name_b ? name_b : name_a;
2485        data.lineno = 0;
2486        data.o = o;
2487        data.ws_rule = whitespace_rule(attr_path);
2488        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2489
2490        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2491                die("unable to read files to diff");
2492
2493        /*
2494         * All the other codepaths check both sides, but not checking
2495         * the "old" side here is deliberate.  We are checking the newly
2496         * introduced changes, and as long as the "new" side is text, we
2497         * can and should check what it introduces.
2498         */
2499        if (diff_filespec_is_binary(two))
2500                goto free_and_return;
2501        else {
2502                /* Crazy xdl interfaces.. */
2503                xpparam_t xpp;
2504                xdemitconf_t xecfg;
2505
2506                memset(&xpp, 0, sizeof(xpp));
2507                memset(&xecfg, 0, sizeof(xecfg));
2508                xecfg.ctxlen = 1; /* at least one context line */
2509                xpp.flags = 0;
2510                xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2511                              &xpp, &xecfg);
2512
2513                if (data.ws_rule & WS_BLANK_AT_EOF) {
2514                        struct emit_callback ecbdata;
2515                        int blank_at_eof;
2516
2517                        ecbdata.ws_rule = data.ws_rule;
2518                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2519                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2520
2521                        if (blank_at_eof) {
2522                                static char *err;
2523                                if (!err)
2524                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2525                                fprintf(o->file, "%s:%d: %s.\n",
2526                                        data.filename, blank_at_eof, err);
2527                                data.status = 1; /* report errors */
2528                        }
2529                }
2530        }
2531 free_and_return:
2532        diff_free_filespec_data(one);
2533        diff_free_filespec_data(two);
2534        if (data.status)
2535                DIFF_OPT_SET(o, CHECK_FAILED);
2536}
2537
2538struct diff_filespec *alloc_filespec(const char *path)
2539{
2540        int namelen = strlen(path);
2541        struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
2542
2543        memset(spec, 0, sizeof(*spec));
2544        spec->path = (char *)(spec + 1);
2545        memcpy(spec->path, path, namelen+1);
2546        spec->count = 1;
2547        spec->is_binary = -1;
2548        return spec;
2549}
2550
2551void free_filespec(struct diff_filespec *spec)
2552{
2553        if (!--spec->count) {
2554                diff_free_filespec_data(spec);
2555                free(spec);
2556        }
2557}
2558
2559void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2560                   int sha1_valid, unsigned short mode)
2561{
2562        if (mode) {
2563                spec->mode = canon_mode(mode);
2564                hashcpy(spec->sha1, sha1);
2565                spec->sha1_valid = sha1_valid;
2566        }
2567}
2568
2569/*
2570 * Given a name and sha1 pair, if the index tells us the file in
2571 * the work tree has that object contents, return true, so that
2572 * prepare_temp_file() does not have to inflate and extract.
2573 */
2574static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2575{
2576        struct cache_entry *ce;
2577        struct stat st;
2578        int pos, len;
2579
2580        /*
2581         * We do not read the cache ourselves here, because the
2582         * benchmark with my previous version that always reads cache
2583         * shows that it makes things worse for diff-tree comparing
2584         * two linux-2.6 kernel trees in an already checked out work
2585         * tree.  This is because most diff-tree comparisons deal with
2586         * only a small number of files, while reading the cache is
2587         * expensive for a large project, and its cost outweighs the
2588         * savings we get by not inflating the object to a temporary
2589         * file.  Practically, this code only helps when we are used
2590         * by diff-cache --cached, which does read the cache before
2591         * calling us.
2592         */
2593        if (!active_cache)
2594                return 0;
2595
2596        /* We want to avoid the working directory if our caller
2597         * doesn't need the data in a normal file, this system
2598         * is rather slow with its stat/open/mmap/close syscalls,
2599         * and the object is contained in a pack file.  The pack
2600         * is probably already open and will be faster to obtain
2601         * the data through than the working directory.  Loose
2602         * objects however would tend to be slower as they need
2603         * to be individually opened and inflated.
2604         */
2605        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2606                return 0;
2607
2608        len = strlen(name);
2609        pos = cache_name_pos(name, len);
2610        if (pos < 0)
2611                return 0;
2612        ce = active_cache[pos];
2613
2614        /*
2615         * This is not the sha1 we are looking for, or
2616         * unreusable because it is not a regular file.
2617         */
2618        if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2619                return 0;
2620
2621        /*
2622         * If ce is marked as "assume unchanged", there is no
2623         * guarantee that work tree matches what we are looking for.
2624         */
2625        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2626                return 0;
2627
2628        /*
2629         * If ce matches the file in the work tree, we can reuse it.
2630         */
2631        if (ce_uptodate(ce) ||
2632            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2633                return 1;
2634
2635        return 0;
2636}
2637
2638static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2639{
2640        int len;
2641        char *data = xmalloc(100), *dirty = "";
2642
2643        /* Are we looking at the work tree? */
2644        if (s->dirty_submodule)
2645                dirty = "-dirty";
2646
2647        len = snprintf(data, 100,
2648                       "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2649        s->data = data;
2650        s->size = len;
2651        s->should_free = 1;
2652        if (size_only) {
2653                s->data = NULL;
2654                free(data);
2655        }
2656        return 0;
2657}
2658
2659/*
2660 * While doing rename detection and pickaxe operation, we may need to
2661 * grab the data for the blob (or file) for our own in-core comparison.
2662 * diff_filespec has data and size fields for this purpose.
2663 */
2664int diff_populate_filespec(struct diff_filespec *s, int size_only)
2665{
2666        int err = 0;
2667        if (!DIFF_FILE_VALID(s))
2668                die("internal error: asking to populate invalid file.");
2669        if (S_ISDIR(s->mode))
2670                return -1;
2671
2672        if (s->data)
2673                return 0;
2674
2675        if (size_only && 0 < s->size)
2676                return 0;
2677
2678        if (S_ISGITLINK(s->mode))
2679                return diff_populate_gitlink(s, size_only);
2680
2681        if (!s->sha1_valid ||
2682            reuse_worktree_file(s->path, s->sha1, 0)) {
2683                struct strbuf buf = STRBUF_INIT;
2684                struct stat st;
2685                int fd;
2686
2687                if (lstat(s->path, &st) < 0) {
2688                        if (errno == ENOENT) {
2689                        err_empty:
2690                                err = -1;
2691                        empty:
2692                                s->data = (char *)"";
2693                                s->size = 0;
2694                                return err;
2695                        }
2696                }
2697                s->size = xsize_t(st.st_size);
2698                if (!s->size)
2699                        goto empty;
2700                if (S_ISLNK(st.st_mode)) {
2701                        struct strbuf sb = STRBUF_INIT;
2702
2703                        if (strbuf_readlink(&sb, s->path, s->size))
2704                                goto err_empty;
2705                        s->size = sb.len;
2706                        s->data = strbuf_detach(&sb, NULL);
2707                        s->should_free = 1;
2708                        return 0;
2709                }
2710                if (size_only)
2711                        return 0;
2712                fd = open(s->path, O_RDONLY);
2713                if (fd < 0)
2714                        goto err_empty;
2715                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2716                close(fd);
2717                s->should_munmap = 1;
2718
2719                /*
2720                 * Convert from working tree format to canonical git format
2721                 */
2722                if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
2723                        size_t size = 0;
2724                        munmap(s->data, s->size);
2725                        s->should_munmap = 0;
2726                        s->data = strbuf_detach(&buf, &size);
2727                        s->size = size;
2728                        s->should_free = 1;
2729                }
2730        }
2731        else {
2732                enum object_type type;
2733                if (size_only) {
2734                        type = sha1_object_info(s->sha1, &s->size);
2735                        if (type < 0)
2736                                die("unable to read %s", sha1_to_hex(s->sha1));
2737                } else {
2738                        s->data = read_sha1_file(s->sha1, &type, &s->size);
2739                        if (!s->data)
2740                                die("unable to read %s", sha1_to_hex(s->sha1));
2741                        s->should_free = 1;
2742                }
2743        }
2744        return 0;
2745}
2746
2747void diff_free_filespec_blob(struct diff_filespec *s)
2748{
2749        if (s->should_free)
2750                free(s->data);
2751        else if (s->should_munmap)
2752                munmap(s->data, s->size);
2753
2754        if (s->should_free || s->should_munmap) {
2755                s->should_free = s->should_munmap = 0;
2756                s->data = NULL;
2757        }
2758}
2759
2760void diff_free_filespec_data(struct diff_filespec *s)
2761{
2762        diff_free_filespec_blob(s);
2763        free(s->cnt_data);
2764        s->cnt_data = NULL;
2765}
2766
2767static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2768                           void *blob,
2769                           unsigned long size,
2770                           const unsigned char *sha1,
2771                           int mode)
2772{
2773        int fd;
2774        struct strbuf buf = STRBUF_INIT;
2775        struct strbuf template = STRBUF_INIT;
2776        char *path_dup = xstrdup(path);
2777        const char *base = basename(path_dup);
2778
2779        /* Generate "XXXXXX_basename.ext" */
2780        strbuf_addstr(&template, "XXXXXX_");
2781        strbuf_addstr(&template, base);
2782
2783        fd = git_mkstemps(temp->tmp_path, PATH_MAX, template.buf,
2784                        strlen(base) + 1);
2785        if (fd < 0)
2786                die_errno("unable to create temp-file");
2787        if (convert_to_working_tree(path,
2788                        (const char *)blob, (size_t)size, &buf)) {
2789                blob = buf.buf;
2790                size = buf.len;
2791        }
2792        if (write_in_full(fd, blob, size) != size)
2793                die_errno("unable to write temp-file");
2794        close(fd);
2795        temp->name = temp->tmp_path;
2796        strcpy(temp->hex, sha1_to_hex(sha1));
2797        temp->hex[40] = 0;
2798        sprintf(temp->mode, "%06o", mode);
2799        strbuf_release(&buf);
2800        strbuf_release(&template);
2801        free(path_dup);
2802}
2803
2804static struct diff_tempfile *prepare_temp_file(const char *name,
2805                struct diff_filespec *one)
2806{
2807        struct diff_tempfile *temp = claim_diff_tempfile();
2808
2809        if (!DIFF_FILE_VALID(one)) {
2810        not_a_valid_file:
2811                /* A '-' entry produces this for file-2, and
2812                 * a '+' entry produces this for file-1.
2813                 */
2814                temp->name = "/dev/null";
2815                strcpy(temp->hex, ".");
2816                strcpy(temp->mode, ".");
2817                return temp;
2818        }
2819
2820        if (!remove_tempfile_installed) {
2821                atexit(remove_tempfile);
2822                sigchain_push_common(remove_tempfile_on_signal);
2823                remove_tempfile_installed = 1;
2824        }
2825
2826        if (!one->sha1_valid ||
2827            reuse_worktree_file(name, one->sha1, 1)) {
2828                struct stat st;
2829                if (lstat(name, &st) < 0) {
2830                        if (errno == ENOENT)
2831                                goto not_a_valid_file;
2832                        die_errno("stat(%s)", name);
2833                }
2834                if (S_ISLNK(st.st_mode)) {
2835                        struct strbuf sb = STRBUF_INIT;
2836                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
2837                                die_errno("readlink(%s)", name);
2838                        prep_temp_blob(name, temp, sb.buf, sb.len,
2839                                       (one->sha1_valid ?
2840                                        one->sha1 : null_sha1),
2841                                       (one->sha1_valid ?
2842                                        one->mode : S_IFLNK));
2843                        strbuf_release(&sb);
2844                }
2845                else {
2846                        /* we can borrow from the file in the work tree */
2847                        temp->name = name;
2848                        if (!one->sha1_valid)
2849                                strcpy(temp->hex, sha1_to_hex(null_sha1));
2850                        else
2851                                strcpy(temp->hex, sha1_to_hex(one->sha1));
2852                        /* Even though we may sometimes borrow the
2853                         * contents from the work tree, we always want
2854                         * one->mode.  mode is trustworthy even when
2855                         * !(one->sha1_valid), as long as
2856                         * DIFF_FILE_VALID(one).
2857                         */
2858                        sprintf(temp->mode, "%06o", one->mode);
2859                }
2860                return temp;
2861        }
2862        else {
2863                if (diff_populate_filespec(one, 0))
2864                        die("cannot read data blob for %s", one->path);
2865                prep_temp_blob(name, temp, one->data, one->size,
2866                               one->sha1, one->mode);
2867        }
2868        return temp;
2869}
2870
2871/* An external diff command takes:
2872 *
2873 * diff-cmd name infile1 infile1-sha1 infile1-mode \
2874 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2875 *
2876 */
2877static void run_external_diff(const char *pgm,
2878                              const char *name,
2879                              const char *other,
2880                              struct diff_filespec *one,
2881                              struct diff_filespec *two,
2882                              const char *xfrm_msg,
2883                              int complete_rewrite)
2884{
2885        const char *spawn_arg[10];
2886        int retval;
2887        const char **arg = &spawn_arg[0];
2888
2889        if (one && two) {
2890                struct diff_tempfile *temp_one, *temp_two;
2891                const char *othername = (other ? other : name);
2892                temp_one = prepare_temp_file(name, one);
2893                temp_two = prepare_temp_file(othername, two);
2894                *arg++ = pgm;
2895                *arg++ = name;
2896                *arg++ = temp_one->name;
2897                *arg++ = temp_one->hex;
2898                *arg++ = temp_one->mode;
2899                *arg++ = temp_two->name;
2900                *arg++ = temp_two->hex;
2901                *arg++ = temp_two->mode;
2902                if (other) {
2903                        *arg++ = other;
2904                        *arg++ = xfrm_msg;
2905                }
2906        } else {
2907                *arg++ = pgm;
2908                *arg++ = name;
2909        }
2910        *arg = NULL;
2911        fflush(NULL);
2912        retval = run_command_v_opt(spawn_arg, RUN_USING_SHELL);
2913        remove_tempfile();
2914        if (retval) {
2915                fprintf(stderr, "external diff died, stopping at %s.\n", name);
2916                exit(1);
2917        }
2918}
2919
2920static int similarity_index(struct diff_filepair *p)
2921{
2922        return p->score * 100 / MAX_SCORE;
2923}
2924
2925static void fill_metainfo(struct strbuf *msg,
2926                          const char *name,
2927                          const char *other,
2928                          struct diff_filespec *one,
2929                          struct diff_filespec *two,
2930                          struct diff_options *o,
2931                          struct diff_filepair *p,
2932                          int *must_show_header,
2933                          int use_color)
2934{
2935        const char *set = diff_get_color(use_color, DIFF_METAINFO);
2936        const char *reset = diff_get_color(use_color, DIFF_RESET);
2937        const char *line_prefix = diff_line_prefix(o);
2938
2939        *must_show_header = 1;
2940        strbuf_init(msg, PATH_MAX * 2 + 300);
2941        switch (p->status) {
2942        case DIFF_STATUS_COPIED:
2943                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2944                            line_prefix, set, similarity_index(p));
2945                strbuf_addf(msg, "%s\n%s%scopy from ",
2946                            reset,  line_prefix, set);
2947                quote_c_style(name, msg, NULL, 0);
2948                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
2949                quote_c_style(other, msg, NULL, 0);
2950                strbuf_addf(msg, "%s\n", reset);
2951                break;
2952        case DIFF_STATUS_RENAMED:
2953                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2954                            line_prefix, set, similarity_index(p));
2955                strbuf_addf(msg, "%s\n%s%srename from ",
2956                            reset, line_prefix, set);
2957                quote_c_style(name, msg, NULL, 0);
2958                strbuf_addf(msg, "%s\n%s%srename to ",
2959                            reset, line_prefix, set);
2960                quote_c_style(other, msg, NULL, 0);
2961                strbuf_addf(msg, "%s\n", reset);
2962                break;
2963        case DIFF_STATUS_MODIFIED:
2964                if (p->score) {
2965                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
2966                                    line_prefix,
2967                                    set, similarity_index(p), reset);
2968                        break;
2969                }
2970                /* fallthru */
2971        default:
2972                *must_show_header = 0;
2973        }
2974        if (one && two && hashcmp(one->sha1, two->sha1)) {
2975                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
2976
2977                if (DIFF_OPT_TST(o, BINARY)) {
2978                        mmfile_t mf;
2979                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
2980                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
2981                                abbrev = 40;
2982                }
2983                strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
2984                            find_unique_abbrev(one->sha1, abbrev));
2985                strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
2986                if (one->mode == two->mode)
2987                        strbuf_addf(msg, " %06o", one->mode);
2988                strbuf_addf(msg, "%s\n", reset);
2989        }
2990}
2991
2992static void run_diff_cmd(const char *pgm,
2993                         const char *name,
2994                         const char *other,
2995                         const char *attr_path,
2996                         struct diff_filespec *one,
2997                         struct diff_filespec *two,
2998                         struct strbuf *msg,
2999                         struct diff_options *o,
3000                         struct diff_filepair *p)
3001{
3002        const char *xfrm_msg = NULL;
3003        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3004        int must_show_header = 0;
3005
3006
3007        if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3008                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3009                if (drv && drv->external)
3010                        pgm = drv->external;
3011        }
3012
3013        if (msg) {
3014                /*
3015                 * don't use colors when the header is intended for an
3016                 * external diff driver
3017                 */
3018                fill_metainfo(msg, name, other, one, two, o, p,
3019                              &must_show_header,
3020                              want_color(o->use_color) && !pgm);
3021                xfrm_msg = msg->len ? msg->buf : NULL;
3022        }
3023
3024        if (pgm) {
3025                run_external_diff(pgm, name, other, one, two, xfrm_msg,
3026                                  complete_rewrite);
3027                return;
3028        }
3029        if (one && two)
3030                builtin_diff(name, other ? other : name,
3031                             one, two, xfrm_msg, must_show_header,
3032                             o, complete_rewrite);
3033        else
3034                fprintf(o->file, "* Unmerged path %s\n", name);
3035}
3036
3037static void diff_fill_sha1_info(struct diff_filespec *one)
3038{
3039        if (DIFF_FILE_VALID(one)) {
3040                if (!one->sha1_valid) {
3041                        struct stat st;
3042                        if (one->is_stdin) {
3043                                hashcpy(one->sha1, null_sha1);
3044                                return;
3045                        }
3046                        if (lstat(one->path, &st) < 0)
3047                                die_errno("stat '%s'", one->path);
3048                        if (index_path(one->sha1, one->path, &st, 0))
3049                                die("cannot hash %s", one->path);
3050                }
3051        }
3052        else
3053                hashclr(one->sha1);
3054}
3055
3056static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3057{
3058        /* Strip the prefix but do not molest /dev/null and absolute paths */
3059        if (*namep && **namep != '/') {
3060                *namep += prefix_length;
3061                if (**namep == '/')
3062                        ++*namep;
3063        }
3064        if (*otherp && **otherp != '/') {
3065                *otherp += prefix_length;
3066                if (**otherp == '/')
3067                        ++*otherp;
3068        }
3069}
3070
3071static void run_diff(struct diff_filepair *p, struct diff_options *o)
3072{
3073        const char *pgm = external_diff();
3074        struct strbuf msg;
3075        struct diff_filespec *one = p->one;
3076        struct diff_filespec *two = p->two;
3077        const char *name;
3078        const char *other;
3079        const char *attr_path;
3080
3081        name  = p->one->path;
3082        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3083        attr_path = name;
3084        if (o->prefix_length)
3085                strip_prefix(o->prefix_length, &name, &other);
3086
3087        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3088                pgm = NULL;
3089
3090        if (DIFF_PAIR_UNMERGED(p)) {
3091                run_diff_cmd(pgm, name, NULL, attr_path,
3092                             NULL, NULL, NULL, o, p);
3093                return;
3094        }
3095
3096        diff_fill_sha1_info(one);
3097        diff_fill_sha1_info(two);
3098
3099        if (!pgm &&
3100            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3101            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3102                /*
3103                 * a filepair that changes between file and symlink
3104                 * needs to be split into deletion and creation.
3105                 */
3106                struct diff_filespec *null = alloc_filespec(two->path);
3107                run_diff_cmd(NULL, name, other, attr_path,
3108                             one, null, &msg, o, p);
3109                free(null);
3110                strbuf_release(&msg);
3111
3112                null = alloc_filespec(one->path);
3113                run_diff_cmd(NULL, name, other, attr_path,
3114                             null, two, &msg, o, p);
3115                free(null);
3116        }
3117        else
3118                run_diff_cmd(pgm, name, other, attr_path,
3119                             one, two, &msg, o, p);
3120
3121        strbuf_release(&msg);
3122}
3123
3124static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3125                         struct diffstat_t *diffstat)
3126{
3127        const char *name;
3128        const char *other;
3129
3130        if (DIFF_PAIR_UNMERGED(p)) {
3131                /* unmerged */
3132                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3133                return;
3134        }
3135
3136        name = p->one->path;
3137        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3138
3139        if (o->prefix_length)
3140                strip_prefix(o->prefix_length, &name, &other);
3141
3142        diff_fill_sha1_info(p->one);
3143        diff_fill_sha1_info(p->two);
3144
3145        builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3146}
3147
3148static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3149{
3150        const char *name;
3151        const char *other;
3152        const char *attr_path;
3153
3154        if (DIFF_PAIR_UNMERGED(p)) {
3155                /* unmerged */
3156                return;
3157        }
3158
3159        name = p->one->path;
3160        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3161        attr_path = other ? other : name;
3162
3163        if (o->prefix_length)
3164                strip_prefix(o->prefix_length, &name, &other);
3165
3166        diff_fill_sha1_info(p->one);
3167        diff_fill_sha1_info(p->two);
3168
3169        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3170}
3171
3172void diff_setup(struct diff_options *options)
3173{
3174        memcpy(options, &default_diff_options, sizeof(*options));
3175
3176        options->file = stdout;
3177
3178        options->line_termination = '\n';
3179        options->break_opt = -1;
3180        options->rename_limit = -1;
3181        options->dirstat_permille = diff_dirstat_permille_default;
3182        options->context = diff_context_default;
3183        DIFF_OPT_SET(options, RENAME_EMPTY);
3184
3185        options->change = diff_change;
3186        options->add_remove = diff_addremove;
3187        options->use_color = diff_use_color_default;
3188        options->detect_rename = diff_detect_rename_default;
3189        options->xdl_opts |= diff_algorithm;
3190
3191        if (diff_no_prefix) {
3192                options->a_prefix = options->b_prefix = "";
3193        } else if (!diff_mnemonic_prefix) {
3194                options->a_prefix = "a/";
3195                options->b_prefix = "b/";
3196        }
3197}
3198
3199void diff_setup_done(struct diff_options *options)
3200{
3201        int count = 0;
3202
3203        if (options->output_format & DIFF_FORMAT_NAME)
3204                count++;
3205        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3206                count++;
3207        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3208                count++;
3209        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3210                count++;
3211        if (count > 1)
3212                die("--name-only, --name-status, --check and -s are mutually exclusive");
3213
3214        /*
3215         * Most of the time we can say "there are changes"
3216         * only by checking if there are changed paths, but
3217         * --ignore-whitespace* options force us to look
3218         * inside contents.
3219         */
3220
3221        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3222            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3223            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3224                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3225        else
3226                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3227
3228        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3229                options->detect_rename = DIFF_DETECT_COPY;
3230
3231        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3232                options->prefix = NULL;
3233        if (options->prefix)
3234                options->prefix_length = strlen(options->prefix);
3235        else
3236                options->prefix_length = 0;
3237
3238        if (options->output_format & (DIFF_FORMAT_NAME |
3239                                      DIFF_FORMAT_NAME_STATUS |
3240                                      DIFF_FORMAT_CHECKDIFF |
3241                                      DIFF_FORMAT_NO_OUTPUT))
3242                options->output_format &= ~(DIFF_FORMAT_RAW |
3243                                            DIFF_FORMAT_NUMSTAT |
3244                                            DIFF_FORMAT_DIFFSTAT |
3245                                            DIFF_FORMAT_SHORTSTAT |
3246                                            DIFF_FORMAT_DIRSTAT |
3247                                            DIFF_FORMAT_SUMMARY |
3248                                            DIFF_FORMAT_PATCH);
3249
3250        /*
3251         * These cases always need recursive; we do not drop caller-supplied
3252         * recursive bits for other formats here.
3253         */
3254        if (options->output_format & (DIFF_FORMAT_PATCH |
3255                                      DIFF_FORMAT_NUMSTAT |
3256                                      DIFF_FORMAT_DIFFSTAT |
3257                                      DIFF_FORMAT_SHORTSTAT |
3258                                      DIFF_FORMAT_DIRSTAT |
3259                                      DIFF_FORMAT_SUMMARY |
3260                                      DIFF_FORMAT_CHECKDIFF))
3261                DIFF_OPT_SET(options, RECURSIVE);
3262        /*
3263         * Also pickaxe would not work very well if you do not say recursive
3264         */
3265        if (options->pickaxe)
3266                DIFF_OPT_SET(options, RECURSIVE);
3267        /*
3268         * When patches are generated, submodules diffed against the work tree
3269         * must be checked for dirtiness too so it can be shown in the output
3270         */
3271        if (options->output_format & DIFF_FORMAT_PATCH)
3272                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3273
3274        if (options->detect_rename && options->rename_limit < 0)
3275                options->rename_limit = diff_rename_limit_default;
3276        if (options->setup & DIFF_SETUP_USE_CACHE) {
3277                if (!active_cache)
3278                        /* read-cache does not die even when it fails
3279                         * so it is safe for us to do this here.  Also
3280                         * it does not smudge active_cache or active_nr
3281                         * when it fails, so we do not have to worry about
3282                         * cleaning it up ourselves either.
3283                         */
3284                        read_cache();
3285        }
3286        if (options->abbrev <= 0 || 40 < options->abbrev)
3287                options->abbrev = 40; /* full */
3288
3289        /*
3290         * It does not make sense to show the first hit we happened
3291         * to have found.  It does not make sense not to return with
3292         * exit code in such a case either.
3293         */
3294        if (DIFF_OPT_TST(options, QUICK)) {
3295                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3296                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3297        }
3298}
3299
3300static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3301{
3302        char c, *eq;
3303        int len;
3304
3305        if (*arg != '-')
3306                return 0;
3307        c = *++arg;
3308        if (!c)
3309                return 0;
3310        if (c == arg_short) {
3311                c = *++arg;
3312                if (!c)
3313                        return 1;
3314                if (val && isdigit(c)) {
3315                        char *end;
3316                        int n = strtoul(arg, &end, 10);
3317                        if (*end)
3318                                return 0;
3319                        *val = n;
3320                        return 1;
3321                }
3322                return 0;
3323        }
3324        if (c != '-')
3325                return 0;
3326        arg++;
3327        eq = strchr(arg, '=');
3328        if (eq)
3329                len = eq - arg;
3330        else
3331                len = strlen(arg);
3332        if (!len || strncmp(arg, arg_long, len))
3333                return 0;
3334        if (eq) {
3335                int n;
3336                char *end;
3337                if (!isdigit(*++eq))
3338                        return 0;
3339                n = strtoul(eq, &end, 10);
3340                if (*end)
3341                        return 0;
3342                *val = n;
3343        }
3344        return 1;
3345}
3346
3347static int diff_scoreopt_parse(const char *opt);
3348
3349static inline int short_opt(char opt, const char **argv,
3350                            const char **optarg)
3351{
3352        const char *arg = argv[0];
3353        if (arg[0] != '-' || arg[1] != opt)
3354                return 0;
3355        if (arg[2] != '\0') {
3356                *optarg = arg + 2;
3357                return 1;
3358        }
3359        if (!argv[1])
3360                die("Option '%c' requires a value", opt);
3361        *optarg = argv[1];
3362        return 2;
3363}
3364
3365int parse_long_opt(const char *opt, const char **argv,
3366                   const char **optarg)
3367{
3368        const char *arg = argv[0];
3369        if (arg[0] != '-' || arg[1] != '-')
3370                return 0;
3371        arg += strlen("--");
3372        if (prefixcmp(arg, opt))
3373                return 0;
3374        arg += strlen(opt);
3375        if (*arg == '=') { /* sticked form: --option=value */
3376                *optarg = arg + 1;
3377                return 1;
3378        }
3379        if (*arg != '\0')
3380                return 0;
3381        /* separate form: --option value */
3382        if (!argv[1])
3383                die("Option '--%s' requires a value", opt);
3384        *optarg = argv[1];
3385        return 2;
3386}
3387
3388static int stat_opt(struct diff_options *options, const char **av)
3389{
3390        const char *arg = av[0];
3391        char *end;
3392        int width = options->stat_width;
3393        int name_width = options->stat_name_width;
3394        int graph_width = options->stat_graph_width;
3395        int count = options->stat_count;
3396        int argcount = 1;
3397
3398        arg += strlen("--stat");
3399        end = (char *)arg;
3400
3401        switch (*arg) {
3402        case '-':
3403                if (!prefixcmp(arg, "-width")) {
3404                        arg += strlen("-width");
3405                        if (*arg == '=')
3406                                width = strtoul(arg + 1, &end, 10);
3407                        else if (!*arg && !av[1])
3408                                die("Option '--stat-width' requires a value");
3409                        else if (!*arg) {
3410                                width = strtoul(av[1], &end, 10);
3411                                argcount = 2;
3412                        }
3413                } else if (!prefixcmp(arg, "-name-width")) {
3414                        arg += strlen("-name-width");
3415                        if (*arg == '=')
3416                                name_width = strtoul(arg + 1, &end, 10);
3417                        else if (!*arg && !av[1])
3418                                die("Option '--stat-name-width' requires a value");
3419                        else if (!*arg) {
3420                                name_width = strtoul(av[1], &end, 10);
3421                                argcount = 2;
3422                        }
3423                } else if (!prefixcmp(arg, "-graph-width")) {
3424                        arg += strlen("-graph-width");
3425                        if (*arg == '=')
3426                                graph_width = strtoul(arg + 1, &end, 10);
3427                        else if (!*arg && !av[1])
3428                                die("Option '--stat-graph-width' requires a value");
3429                        else if (!*arg) {
3430                                graph_width = strtoul(av[1], &end, 10);
3431                                argcount = 2;
3432                        }
3433                } else if (!prefixcmp(arg, "-count")) {
3434                        arg += strlen("-count");
3435                        if (*arg == '=')
3436                                count = strtoul(arg + 1, &end, 10);
3437                        else if (!*arg && !av[1])
3438                                die("Option '--stat-count' requires a value");
3439                        else if (!*arg) {
3440                                count = strtoul(av[1], &end, 10);
3441                                argcount = 2;
3442                        }
3443                }
3444                break;
3445        case '=':
3446                width = strtoul(arg+1, &end, 10);
3447                if (*end == ',')
3448                        name_width = strtoul(end+1, &end, 10);
3449                if (*end == ',')
3450                        count = strtoul(end+1, &end, 10);
3451        }
3452
3453        /* Important! This checks all the error cases! */
3454        if (*end)
3455                return 0;
3456        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3457        options->stat_name_width = name_width;
3458        options->stat_graph_width = graph_width;
3459        options->stat_width = width;
3460        options->stat_count = count;
3461        return argcount;
3462}
3463
3464static int parse_dirstat_opt(struct diff_options *options, const char *params)
3465{
3466        struct strbuf errmsg = STRBUF_INIT;
3467        if (parse_dirstat_params(options, params, &errmsg))
3468                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3469                    errmsg.buf);
3470        strbuf_release(&errmsg);
3471        /*
3472         * The caller knows a dirstat-related option is given from the command
3473         * line; allow it to say "return this_function();"
3474         */
3475        options->output_format |= DIFF_FORMAT_DIRSTAT;
3476        return 1;
3477}
3478
3479static int parse_submodule_opt(struct diff_options *options, const char *value)
3480{
3481        if (parse_submodule_params(options, value))
3482                die(_("Failed to parse --submodule option parameter: '%s'"),
3483                        value);
3484        return 1;
3485}
3486
3487int diff_opt_parse(struct diff_options *options, const char **av, int ac)
3488{
3489        const char *arg = av[0];
3490        const char *optarg;
3491        int argcount;
3492
3493        /* Output format options */
3494        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch"))
3495                options->output_format |= DIFF_FORMAT_PATCH;
3496        else if (opt_arg(arg, 'U', "unified", &options->context))
3497                options->output_format |= DIFF_FORMAT_PATCH;
3498        else if (!strcmp(arg, "--raw"))
3499                options->output_format |= DIFF_FORMAT_RAW;
3500        else if (!strcmp(arg, "--patch-with-raw"))
3501                options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
3502        else if (!strcmp(arg, "--numstat"))
3503                options->output_format |= DIFF_FORMAT_NUMSTAT;
3504        else if (!strcmp(arg, "--shortstat"))
3505                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3506        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3507                return parse_dirstat_opt(options, "");
3508        else if (!prefixcmp(arg, "-X"))
3509                return parse_dirstat_opt(options, arg + 2);
3510        else if (!prefixcmp(arg, "--dirstat="))
3511                return parse_dirstat_opt(options, arg + 10);
3512        else if (!strcmp(arg, "--cumulative"))
3513                return parse_dirstat_opt(options, "cumulative");
3514        else if (!strcmp(arg, "--dirstat-by-file"))
3515                return parse_dirstat_opt(options, "files");
3516        else if (!prefixcmp(arg, "--dirstat-by-file=")) {
3517                parse_dirstat_opt(options, "files");
3518                return parse_dirstat_opt(options, arg + 18);
3519        }
3520        else if (!strcmp(arg, "--check"))
3521                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3522        else if (!strcmp(arg, "--summary"))
3523                options->output_format |= DIFF_FORMAT_SUMMARY;
3524        else if (!strcmp(arg, "--patch-with-stat"))
3525                options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
3526        else if (!strcmp(arg, "--name-only"))
3527                options->output_format |= DIFF_FORMAT_NAME;
3528        else if (!strcmp(arg, "--name-status"))
3529                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3530        else if (!strcmp(arg, "-s"))
3531                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3532        else if (!prefixcmp(arg, "--stat"))
3533                /* --stat, --stat-width, --stat-name-width, or --stat-count */
3534                return stat_opt(options, av);
3535
3536        /* renames options */
3537        else if (!prefixcmp(arg, "-B") || !prefixcmp(arg, "--break-rewrites=") ||
3538                 !strcmp(arg, "--break-rewrites")) {
3539                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3540                        return error("invalid argument to -B: %s", arg+2);
3541        }
3542        else if (!prefixcmp(arg, "-M") || !prefixcmp(arg, "--find-renames=") ||
3543                 !strcmp(arg, "--find-renames")) {
3544                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3545                        return error("invalid argument to -M: %s", arg+2);
3546                options->detect_rename = DIFF_DETECT_RENAME;
3547        }
3548        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3549                options->irreversible_delete = 1;
3550        }
3551        else if (!prefixcmp(arg, "-C") || !prefixcmp(arg, "--find-copies=") ||
3552                 !strcmp(arg, "--find-copies")) {
3553                if (options->detect_rename == DIFF_DETECT_COPY)
3554                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3555                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3556                        return error("invalid argument to -C: %s", arg+2);
3557                options->detect_rename = DIFF_DETECT_COPY;
3558        }
3559        else if (!strcmp(arg, "--no-renames"))
3560                options->detect_rename = 0;
3561        else if (!strcmp(arg, "--rename-empty"))
3562                DIFF_OPT_SET(options, RENAME_EMPTY);
3563        else if (!strcmp(arg, "--no-rename-empty"))
3564                DIFF_OPT_CLR(options, RENAME_EMPTY);
3565        else if (!strcmp(arg, "--relative"))
3566                DIFF_OPT_SET(options, RELATIVE_NAME);
3567        else if (!prefixcmp(arg, "--relative=")) {
3568                DIFF_OPT_SET(options, RELATIVE_NAME);
3569                options->prefix = arg + 11;
3570        }
3571
3572        /* xdiff options */
3573        else if (!strcmp(arg, "--minimal"))
3574                DIFF_XDL_SET(options, NEED_MINIMAL);
3575        else if (!strcmp(arg, "--no-minimal"))
3576                DIFF_XDL_CLR(options, NEED_MINIMAL);
3577        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3578                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3579        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3580                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3581        else if (!strcmp(arg, "--ignore-space-at-eol"))
3582                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3583        else if (!strcmp(arg, "--patience"))
3584                options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3585        else if (!strcmp(arg, "--histogram"))
3586                options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3587        else if (!prefixcmp(arg, "--diff-algorithm=")) {
3588                long value = parse_algorithm_value(arg+17);
3589                if (value < 0)
3590                        return error("option diff-algorithm accepts \"myers\", "
3591                                     "\"minimal\", \"patience\" and \"histogram\"");
3592                /* clear out previous settings */
3593                DIFF_XDL_CLR(options, NEED_MINIMAL);
3594                options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3595                options->xdl_opts |= value;
3596        }
3597
3598        /* flags options */
3599        else if (!strcmp(arg, "--binary")) {
3600                options->output_format |= DIFF_FORMAT_PATCH;
3601                DIFF_OPT_SET(options, BINARY);
3602        }
3603        else if (!strcmp(arg, "--full-index"))
3604                DIFF_OPT_SET(options, FULL_INDEX);
3605        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3606                DIFF_OPT_SET(options, TEXT);
3607        else if (!strcmp(arg, "-R"))
3608                DIFF_OPT_SET(options, REVERSE_DIFF);
3609        else if (!strcmp(arg, "--find-copies-harder"))
3610                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3611        else if (!strcmp(arg, "--follow"))
3612                DIFF_OPT_SET(options, FOLLOW_RENAMES);
3613        else if (!strcmp(arg, "--no-follow"))
3614                DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3615        else if (!strcmp(arg, "--color"))
3616                options->use_color = 1;
3617        else if (!prefixcmp(arg, "--color=")) {
3618                int value = git_config_colorbool(NULL, arg+8);
3619                if (value < 0)
3620                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
3621                options->use_color = value;
3622        }
3623        else if (!strcmp(arg, "--no-color"))
3624                options->use_color = 0;
3625        else if (!strcmp(arg, "--color-words")) {
3626                options->use_color = 1;
3627                options->word_diff = DIFF_WORDS_COLOR;
3628        }
3629        else if (!prefixcmp(arg, "--color-words=")) {
3630                options->use_color = 1;
3631                options->word_diff = DIFF_WORDS_COLOR;
3632                options->word_regex = arg + 14;
3633        }
3634        else if (!strcmp(arg, "--word-diff")) {
3635                if (options->word_diff == DIFF_WORDS_NONE)
3636                        options->word_diff = DIFF_WORDS_PLAIN;
3637        }
3638        else if (!prefixcmp(arg, "--word-diff=")) {
3639                const char *type = arg + 12;
3640                if (!strcmp(type, "plain"))
3641                        options->word_diff = DIFF_WORDS_PLAIN;
3642                else if (!strcmp(type, "color")) {
3643                        options->use_color = 1;
3644                        options->word_diff = DIFF_WORDS_COLOR;
3645                }
3646                else if (!strcmp(type, "porcelain"))
3647                        options->word_diff = DIFF_WORDS_PORCELAIN;
3648                else if (!strcmp(type, "none"))
3649                        options->word_diff = DIFF_WORDS_NONE;
3650                else
3651                        die("bad --word-diff argument: %s", type);
3652        }
3653        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3654                if (options->word_diff == DIFF_WORDS_NONE)
3655                        options->word_diff = DIFF_WORDS_PLAIN;
3656                options->word_regex = optarg;
3657                return argcount;
3658        }
3659        else if (!strcmp(arg, "--exit-code"))
3660                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3661        else if (!strcmp(arg, "--quiet"))
3662                DIFF_OPT_SET(options, QUICK);
3663        else if (!strcmp(arg, "--ext-diff"))
3664                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3665        else if (!strcmp(arg, "--no-ext-diff"))
3666                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3667        else if (!strcmp(arg, "--textconv"))
3668                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3669        else if (!strcmp(arg, "--no-textconv"))
3670                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3671        else if (!strcmp(arg, "--ignore-submodules")) {
3672                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3673                handle_ignore_submodules_arg(options, "all");
3674        } else if (!prefixcmp(arg, "--ignore-submodules=")) {
3675                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3676                handle_ignore_submodules_arg(options, arg + 20);
3677        } else if (!strcmp(arg, "--submodule"))
3678                DIFF_OPT_SET(options, SUBMODULE_LOG);
3679        else if (!prefixcmp(arg, "--submodule="))
3680                return parse_submodule_opt(options, arg + 12);
3681
3682        /* misc options */
3683        else if (!strcmp(arg, "-z"))
3684                options->line_termination = 0;
3685        else if ((argcount = short_opt('l', av, &optarg))) {
3686                options->rename_limit = strtoul(optarg, NULL, 10);
3687                return argcount;
3688        }
3689        else if ((argcount = short_opt('S', av, &optarg))) {
3690                options->pickaxe = optarg;
3691                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3692                return argcount;
3693        } else if ((argcount = short_opt('G', av, &optarg))) {
3694                options->pickaxe = optarg;
3695                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3696                return argcount;
3697        }
3698        else if (!strcmp(arg, "--pickaxe-all"))
3699                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3700        else if (!strcmp(arg, "--pickaxe-regex"))
3701                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3702        else if ((argcount = short_opt('O', av, &optarg))) {
3703                options->orderfile = optarg;
3704                return argcount;
3705        }
3706        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3707                options->filter = optarg;
3708                return argcount;
3709        }
3710        else if (!strcmp(arg, "--abbrev"))
3711                options->abbrev = DEFAULT_ABBREV;
3712        else if (!prefixcmp(arg, "--abbrev=")) {
3713                options->abbrev = strtoul(arg + 9, NULL, 10);
3714                if (options->abbrev < MINIMUM_ABBREV)
3715                        options->abbrev = MINIMUM_ABBREV;
3716                else if (40 < options->abbrev)
3717                        options->abbrev = 40;
3718        }
3719        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3720                options->a_prefix = optarg;
3721                return argcount;
3722        }
3723        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3724                options->b_prefix = optarg;
3725                return argcount;
3726        }
3727        else if (!strcmp(arg, "--no-prefix"))
3728                options->a_prefix = options->b_prefix = "";
3729        else if (opt_arg(arg, '\0', "inter-hunk-context",
3730                         &options->interhunkcontext))
3731                ;
3732        else if (!strcmp(arg, "-W"))
3733                DIFF_OPT_SET(options, FUNCCONTEXT);
3734        else if (!strcmp(arg, "--function-context"))
3735                DIFF_OPT_SET(options, FUNCCONTEXT);
3736        else if (!strcmp(arg, "--no-function-context"))
3737                DIFF_OPT_CLR(options, FUNCCONTEXT);
3738        else if ((argcount = parse_long_opt("output", av, &optarg))) {
3739                options->file = fopen(optarg, "w");
3740                if (!options->file)
3741                        die_errno("Could not open '%s'", optarg);
3742                options->close_file = 1;
3743                return argcount;
3744        } else
3745                return 0;
3746        return 1;
3747}
3748
3749int parse_rename_score(const char **cp_p)
3750{
3751        unsigned long num, scale;
3752        int ch, dot;
3753        const char *cp = *cp_p;
3754
3755        num = 0;
3756        scale = 1;
3757        dot = 0;
3758        for (;;) {
3759                ch = *cp;
3760                if ( !dot && ch == '.' ) {
3761                        scale = 1;
3762                        dot = 1;
3763                } else if ( ch == '%' ) {
3764                        scale = dot ? scale*100 : 100;
3765                        cp++;   /* % is always at the end */
3766                        break;
3767                } else if ( ch >= '0' && ch <= '9' ) {
3768                        if ( scale < 100000 ) {
3769                                scale *= 10;
3770                                num = (num*10) + (ch-'0');
3771                        }
3772                } else {
3773                        break;
3774                }
3775                cp++;
3776        }
3777        *cp_p = cp;
3778
3779        /* user says num divided by scale and we say internally that
3780         * is MAX_SCORE * num / scale.
3781         */
3782        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
3783}
3784
3785static int diff_scoreopt_parse(const char *opt)
3786{
3787        int opt1, opt2, cmd;
3788
3789        if (*opt++ != '-')
3790                return -1;
3791        cmd = *opt++;
3792        if (cmd == '-') {
3793                /* convert the long-form arguments into short-form versions */
3794                if (!prefixcmp(opt, "break-rewrites")) {
3795                        opt += strlen("break-rewrites");
3796                        if (*opt == 0 || *opt++ == '=')
3797                                cmd = 'B';
3798                } else if (!prefixcmp(opt, "find-copies")) {
3799                        opt += strlen("find-copies");
3800                        if (*opt == 0 || *opt++ == '=')
3801                                cmd = 'C';
3802                } else if (!prefixcmp(opt, "find-renames")) {
3803                        opt += strlen("find-renames");
3804                        if (*opt == 0 || *opt++ == '=')
3805                                cmd = 'M';
3806                }
3807        }
3808        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
3809                return -1; /* that is not a -M, -C nor -B option */
3810
3811        opt1 = parse_rename_score(&opt);
3812        if (cmd != 'B')
3813                opt2 = 0;
3814        else {
3815                if (*opt == 0)
3816                        opt2 = 0;
3817                else if (*opt != '/')
3818                        return -1; /* we expect -B80/99 or -B80 */
3819                else {
3820                        opt++;
3821                        opt2 = parse_rename_score(&opt);
3822                }
3823        }
3824        if (*opt != 0)
3825                return -1;
3826        return opt1 | (opt2 << 16);
3827}
3828
3829struct diff_queue_struct diff_queued_diff;
3830
3831void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
3832{
3833        if (queue->alloc <= queue->nr) {
3834                queue->alloc = alloc_nr(queue->alloc);
3835                queue->queue = xrealloc(queue->queue,
3836                                        sizeof(dp) * queue->alloc);
3837        }
3838        queue->queue[queue->nr++] = dp;
3839}
3840
3841struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
3842                                 struct diff_filespec *one,
3843                                 struct diff_filespec *two)
3844{
3845        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
3846        dp->one = one;
3847        dp->two = two;
3848        if (queue)
3849                diff_q(queue, dp);
3850        return dp;
3851}
3852
3853void diff_free_filepair(struct diff_filepair *p)
3854{
3855        free_filespec(p->one);
3856        free_filespec(p->two);
3857        free(p);
3858}
3859
3860/* This is different from find_unique_abbrev() in that
3861 * it stuffs the result with dots for alignment.
3862 */
3863const char *diff_unique_abbrev(const unsigned char *sha1, int len)
3864{
3865        int abblen;
3866        const char *abbrev;
3867        if (len == 40)
3868                return sha1_to_hex(sha1);
3869
3870        abbrev = find_unique_abbrev(sha1, len);
3871        abblen = strlen(abbrev);
3872        if (abblen < 37) {
3873                static char hex[41];
3874                if (len < abblen && abblen <= len + 2)
3875                        sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
3876                else
3877                        sprintf(hex, "%s...", abbrev);
3878                return hex;
3879        }
3880        return sha1_to_hex(sha1);
3881}
3882
3883static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
3884{
3885        int line_termination = opt->line_termination;
3886        int inter_name_termination = line_termination ? '\t' : '\0';
3887
3888        fprintf(opt->file, "%s", diff_line_prefix(opt));
3889        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
3890                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
3891                        diff_unique_abbrev(p->one->sha1, opt->abbrev));
3892                fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
3893        }
3894        if (p->score) {
3895                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
3896                        inter_name_termination);
3897        } else {
3898                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
3899        }
3900
3901        if (p->status == DIFF_STATUS_COPIED ||
3902            p->status == DIFF_STATUS_RENAMED) {
3903                const char *name_a, *name_b;
3904                name_a = p->one->path;
3905                name_b = p->two->path;
3906                strip_prefix(opt->prefix_length, &name_a, &name_b);
3907                write_name_quoted(name_a, opt->file, inter_name_termination);
3908                write_name_quoted(name_b, opt->file, line_termination);
3909        } else {
3910                const char *name_a, *name_b;
3911                name_a = p->one->mode ? p->one->path : p->two->path;
3912                name_b = NULL;
3913                strip_prefix(opt->prefix_length, &name_a, &name_b);
3914                write_name_quoted(name_a, opt->file, line_termination);
3915        }
3916}
3917
3918int diff_unmodified_pair(struct diff_filepair *p)
3919{
3920        /* This function is written stricter than necessary to support
3921         * the currently implemented transformers, but the idea is to
3922         * let transformers to produce diff_filepairs any way they want,
3923         * and filter and clean them up here before producing the output.
3924         */
3925        struct diff_filespec *one = p->one, *two = p->two;
3926
3927        if (DIFF_PAIR_UNMERGED(p))
3928                return 0; /* unmerged is interesting */
3929
3930        /* deletion, addition, mode or type change
3931         * and rename are all interesting.
3932         */
3933        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
3934            DIFF_PAIR_MODE_CHANGED(p) ||
3935            strcmp(one->path, two->path))
3936                return 0;
3937
3938        /* both are valid and point at the same path.  that is, we are
3939         * dealing with a change.
3940         */
3941        if (one->sha1_valid && two->sha1_valid &&
3942            !hashcmp(one->sha1, two->sha1) &&
3943            !one->dirty_submodule && !two->dirty_submodule)
3944                return 1; /* no change */
3945        if (!one->sha1_valid && !two->sha1_valid)
3946                return 1; /* both look at the same file on the filesystem. */
3947        return 0;
3948}
3949
3950static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
3951{
3952        if (diff_unmodified_pair(p))
3953                return;
3954
3955        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3956            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3957                return; /* no tree diffs in patch format */
3958
3959        run_diff(p, o);
3960}
3961
3962static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
3963                            struct diffstat_t *diffstat)
3964{
3965        if (diff_unmodified_pair(p))
3966                return;
3967
3968        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3969            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3970                return; /* no useful stat for tree diffs */
3971
3972        run_diffstat(p, o, diffstat);
3973}
3974
3975static void diff_flush_checkdiff(struct diff_filepair *p,
3976                struct diff_options *o)
3977{
3978        if (diff_unmodified_pair(p))
3979                return;
3980
3981        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3982            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3983                return; /* nothing to check in tree diffs */
3984
3985        run_checkdiff(p, o);
3986}
3987
3988int diff_queue_is_empty(void)
3989{
3990        struct diff_queue_struct *q = &diff_queued_diff;
3991        int i;
3992        for (i = 0; i < q->nr; i++)
3993                if (!diff_unmodified_pair(q->queue[i]))
3994                        return 0;
3995        return 1;
3996}
3997
3998#if DIFF_DEBUG
3999void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4000{
4001        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4002                x, one ? one : "",
4003                s->path,
4004                DIFF_FILE_VALID(s) ? "valid" : "invalid",
4005                s->mode,
4006                s->sha1_valid ? sha1_to_hex(s->sha1) : "");
4007        fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
4008                x, one ? one : "",
4009                s->size, s->xfrm_flags);
4010}
4011
4012void diff_debug_filepair(const struct diff_filepair *p, int i)
4013{
4014        diff_debug_filespec(p->one, i, "one");
4015        diff_debug_filespec(p->two, i, "two");
4016        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4017                p->score, p->status ? p->status : '?',
4018                p->one->rename_used, p->broken_pair);
4019}
4020
4021void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4022{
4023        int i;
4024        if (msg)
4025                fprintf(stderr, "%s\n", msg);
4026        fprintf(stderr, "q->nr = %d\n", q->nr);
4027        for (i = 0; i < q->nr; i++) {
4028                struct diff_filepair *p = q->queue[i];
4029                diff_debug_filepair(p, i);
4030        }
4031}
4032#endif
4033
4034static void diff_resolve_rename_copy(void)
4035{
4036        int i;
4037        struct diff_filepair *p;
4038        struct diff_queue_struct *q = &diff_queued_diff;
4039
4040        diff_debug_queue("resolve-rename-copy", q);
4041
4042        for (i = 0; i < q->nr; i++) {
4043                p = q->queue[i];
4044                p->status = 0; /* undecided */
4045                if (DIFF_PAIR_UNMERGED(p))
4046                        p->status = DIFF_STATUS_UNMERGED;
4047                else if (!DIFF_FILE_VALID(p->one))
4048                        p->status = DIFF_STATUS_ADDED;
4049                else if (!DIFF_FILE_VALID(p->two))
4050                        p->status = DIFF_STATUS_DELETED;
4051                else if (DIFF_PAIR_TYPE_CHANGED(p))
4052                        p->status = DIFF_STATUS_TYPE_CHANGED;
4053
4054                /* from this point on, we are dealing with a pair
4055                 * whose both sides are valid and of the same type, i.e.
4056                 * either in-place edit or rename/copy edit.
4057                 */
4058                else if (DIFF_PAIR_RENAME(p)) {
4059                        /*
4060                         * A rename might have re-connected a broken
4061                         * pair up, causing the pathnames to be the
4062                         * same again. If so, that's not a rename at
4063                         * all, just a modification..
4064                         *
4065                         * Otherwise, see if this source was used for
4066                         * multiple renames, in which case we decrement
4067                         * the count, and call it a copy.
4068                         */
4069                        if (!strcmp(p->one->path, p->two->path))
4070                                p->status = DIFF_STATUS_MODIFIED;
4071                        else if (--p->one->rename_used > 0)
4072                                p->status = DIFF_STATUS_COPIED;
4073                        else
4074                                p->status = DIFF_STATUS_RENAMED;
4075                }
4076                else if (hashcmp(p->one->sha1, p->two->sha1) ||
4077                         p->one->mode != p->two->mode ||
4078                         p->one->dirty_submodule ||
4079                         p->two->dirty_submodule ||
4080                         is_null_sha1(p->one->sha1))
4081                        p->status = DIFF_STATUS_MODIFIED;
4082                else {
4083                        /* This is a "no-change" entry and should not
4084                         * happen anymore, but prepare for broken callers.
4085                         */
4086                        error("feeding unmodified %s to diffcore",
4087                              p->one->path);
4088                        p->status = DIFF_STATUS_UNKNOWN;
4089                }
4090        }
4091        diff_debug_queue("resolve-rename-copy done", q);
4092}
4093
4094static int check_pair_status(struct diff_filepair *p)
4095{
4096        switch (p->status) {
4097        case DIFF_STATUS_UNKNOWN:
4098                return 0;
4099        case 0:
4100                die("internal error in diff-resolve-rename-copy");
4101        default:
4102                return 1;
4103        }
4104}
4105
4106static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4107{
4108        int fmt = opt->output_format;
4109
4110        if (fmt & DIFF_FORMAT_CHECKDIFF)
4111                diff_flush_checkdiff(p, opt);
4112        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4113                diff_flush_raw(p, opt);
4114        else if (fmt & DIFF_FORMAT_NAME) {
4115                const char *name_a, *name_b;
4116                name_a = p->two->path;
4117                name_b = NULL;
4118                strip_prefix(opt->prefix_length, &name_a, &name_b);
4119                write_name_quoted(name_a, opt->file, opt->line_termination);
4120        }
4121}
4122
4123static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4124{
4125        if (fs->mode)
4126                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4127        else
4128                fprintf(file, " %s ", newdelete);
4129        write_name_quoted(fs->path, file, '\n');
4130}
4131
4132
4133static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4134                const char *line_prefix)
4135{
4136        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4137                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4138                        p->two->mode, show_name ? ' ' : '\n');
4139                if (show_name) {
4140                        write_name_quoted(p->two->path, file, '\n');
4141                }
4142        }
4143}
4144
4145static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4146                        const char *line_prefix)
4147{
4148        char *names = pprint_rename(p->one->path, p->two->path);
4149
4150        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4151        free(names);
4152        show_mode_change(file, p, 0, line_prefix);
4153}
4154
4155static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4156{
4157        FILE *file = opt->file;
4158        const char *line_prefix = diff_line_prefix(opt);
4159
4160        switch(p->status) {
4161        case DIFF_STATUS_DELETED:
4162                fputs(line_prefix, file);
4163                show_file_mode_name(file, "delete", p->one);
4164                break;
4165        case DIFF_STATUS_ADDED:
4166                fputs(line_prefix, file);
4167                show_file_mode_name(file, "create", p->two);
4168                break;
4169        case DIFF_STATUS_COPIED:
4170                fputs(line_prefix, file);
4171                show_rename_copy(file, "copy", p, line_prefix);
4172                break;
4173        case DIFF_STATUS_RENAMED:
4174                fputs(line_prefix, file);
4175                show_rename_copy(file, "rename", p, line_prefix);
4176                break;
4177        default:
4178                if (p->score) {
4179                        fprintf(file, "%s rewrite ", line_prefix);
4180                        write_name_quoted(p->two->path, file, ' ');
4181                        fprintf(file, "(%d%%)\n", similarity_index(p));
4182                }
4183                show_mode_change(file, p, !p->score, line_prefix);
4184                break;
4185        }
4186}
4187
4188struct patch_id_t {
4189        git_SHA_CTX *ctx;
4190        int patchlen;
4191};
4192
4193static int remove_space(char *line, int len)
4194{
4195        int i;
4196        char *dst = line;
4197        unsigned char c;
4198
4199        for (i = 0; i < len; i++)
4200                if (!isspace((c = line[i])))
4201                        *dst++ = c;
4202
4203        return dst - line;
4204}
4205
4206static void patch_id_consume(void *priv, char *line, unsigned long len)
4207{
4208        struct patch_id_t *data = priv;
4209        int new_len;
4210
4211        /* Ignore line numbers when computing the SHA1 of the patch */
4212        if (!prefixcmp(line, "@@ -"))
4213                return;
4214
4215        new_len = remove_space(line, len);
4216
4217        git_SHA1_Update(data->ctx, line, new_len);
4218        data->patchlen += new_len;
4219}
4220
4221/* returns 0 upon success, and writes result into sha1 */
4222static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
4223{
4224        struct diff_queue_struct *q = &diff_queued_diff;
4225        int i;
4226        git_SHA_CTX ctx;
4227        struct patch_id_t data;
4228        char buffer[PATH_MAX * 4 + 20];
4229
4230        git_SHA1_Init(&ctx);
4231        memset(&data, 0, sizeof(struct patch_id_t));
4232        data.ctx = &ctx;
4233
4234        for (i = 0; i < q->nr; i++) {
4235                xpparam_t xpp;
4236                xdemitconf_t xecfg;
4237                mmfile_t mf1, mf2;
4238                struct diff_filepair *p = q->queue[i];
4239                int len1, len2;
4240
4241                memset(&xpp, 0, sizeof(xpp));
4242                memset(&xecfg, 0, sizeof(xecfg));
4243                if (p->status == 0)
4244                        return error("internal diff status error");
4245                if (p->status == DIFF_STATUS_UNKNOWN)
4246                        continue;
4247                if (diff_unmodified_pair(p))
4248                        continue;
4249                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4250                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4251                        continue;
4252                if (DIFF_PAIR_UNMERGED(p))
4253                        continue;
4254
4255                diff_fill_sha1_info(p->one);
4256                diff_fill_sha1_info(p->two);
4257                if (fill_mmfile(&mf1, p->one) < 0 ||
4258                                fill_mmfile(&mf2, p->two) < 0)
4259                        return error("unable to read files to diff");
4260
4261                len1 = remove_space(p->one->path, strlen(p->one->path));
4262                len2 = remove_space(p->two->path, strlen(p->two->path));
4263                if (p->one->mode == 0)
4264                        len1 = snprintf(buffer, sizeof(buffer),
4265                                        "diff--gita/%.*sb/%.*s"
4266                                        "newfilemode%06o"
4267                                        "---/dev/null"
4268                                        "+++b/%.*s",
4269                                        len1, p->one->path,
4270                                        len2, p->two->path,
4271                                        p->two->mode,
4272                                        len2, p->two->path);
4273                else if (p->two->mode == 0)
4274                        len1 = snprintf(buffer, sizeof(buffer),
4275                                        "diff--gita/%.*sb/%.*s"
4276                                        "deletedfilemode%06o"
4277                                        "---a/%.*s"
4278                                        "+++/dev/null",
4279                                        len1, p->one->path,
4280                                        len2, p->two->path,
4281                                        p->one->mode,
4282                                        len1, p->one->path);
4283                else
4284                        len1 = snprintf(buffer, sizeof(buffer),
4285                                        "diff--gita/%.*sb/%.*s"
4286                                        "---a/%.*s"
4287                                        "+++b/%.*s",
4288                                        len1, p->one->path,
4289                                        len2, p->two->path,
4290                                        len1, p->one->path,
4291                                        len2, p->two->path);
4292                git_SHA1_Update(&ctx, buffer, len1);
4293
4294                if (diff_filespec_is_binary(p->one) ||
4295                    diff_filespec_is_binary(p->two)) {
4296                        git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4297                        git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4298                        continue;
4299                }
4300
4301                xpp.flags = 0;
4302                xecfg.ctxlen = 3;
4303                xecfg.flags = 0;
4304                xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4305                              &xpp, &xecfg);
4306        }
4307
4308        git_SHA1_Final(sha1, &ctx);
4309        return 0;
4310}
4311
4312int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4313{
4314        struct diff_queue_struct *q = &diff_queued_diff;
4315        int i;
4316        int result = diff_get_patch_id(options, sha1);
4317
4318        for (i = 0; i < q->nr; i++)
4319                diff_free_filepair(q->queue[i]);
4320
4321        free(q->queue);
4322        DIFF_QUEUE_CLEAR(q);
4323
4324        return result;
4325}
4326
4327static int is_summary_empty(const struct diff_queue_struct *q)
4328{
4329        int i;
4330
4331        for (i = 0; i < q->nr; i++) {
4332                const struct diff_filepair *p = q->queue[i];
4333
4334                switch (p->status) {
4335                case DIFF_STATUS_DELETED:
4336                case DIFF_STATUS_ADDED:
4337                case DIFF_STATUS_COPIED:
4338                case DIFF_STATUS_RENAMED:
4339                        return 0;
4340                default:
4341                        if (p->score)
4342                                return 0;
4343                        if (p->one->mode && p->two->mode &&
4344                            p->one->mode != p->two->mode)
4345                                return 0;
4346                        break;
4347                }
4348        }
4349        return 1;
4350}
4351
4352static const char rename_limit_warning[] =
4353"inexact rename detection was skipped due to too many files.";
4354
4355static const char degrade_cc_to_c_warning[] =
4356"only found copies from modified paths due to too many files.";
4357
4358static const char rename_limit_advice[] =
4359"you may want to set your %s variable to at least "
4360"%d and retry the command.";
4361
4362void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4363{
4364        if (degraded_cc)
4365                warning(degrade_cc_to_c_warning);
4366        else if (needed)
4367                warning(rename_limit_warning);
4368        else
4369                return;
4370        if (0 < needed && needed < 32767)
4371                warning(rename_limit_advice, varname, needed);
4372}
4373
4374void diff_flush(struct diff_options *options)
4375{
4376        struct diff_queue_struct *q = &diff_queued_diff;
4377        int i, output_format = options->output_format;
4378        int separator = 0;
4379        int dirstat_by_line = 0;
4380
4381        /*
4382         * Order: raw, stat, summary, patch
4383         * or:    name/name-status/checkdiff (other bits clear)
4384         */
4385        if (!q->nr)
4386                goto free_queue;
4387
4388        if (output_format & (DIFF_FORMAT_RAW |
4389                             DIFF_FORMAT_NAME |
4390                             DIFF_FORMAT_NAME_STATUS |
4391                             DIFF_FORMAT_CHECKDIFF)) {
4392                for (i = 0; i < q->nr; i++) {
4393                        struct diff_filepair *p = q->queue[i];
4394                        if (check_pair_status(p))
4395                                flush_one_pair(p, options);
4396                }
4397                separator++;
4398        }
4399
4400        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4401                dirstat_by_line = 1;
4402
4403        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4404            dirstat_by_line) {
4405                struct diffstat_t diffstat;
4406
4407                memset(&diffstat, 0, sizeof(struct diffstat_t));
4408                for (i = 0; i < q->nr; i++) {
4409                        struct diff_filepair *p = q->queue[i];
4410                        if (check_pair_status(p))
4411                                diff_flush_stat(p, options, &diffstat);
4412                }
4413                if (output_format & DIFF_FORMAT_NUMSTAT)
4414                        show_numstat(&diffstat, options);
4415                if (output_format & DIFF_FORMAT_DIFFSTAT)
4416                        show_stats(&diffstat, options);
4417                if (output_format & DIFF_FORMAT_SHORTSTAT)
4418                        show_shortstats(&diffstat, options);
4419                if (output_format & DIFF_FORMAT_DIRSTAT)
4420                        show_dirstat_by_line(&diffstat, options);
4421                free_diffstat_info(&diffstat);
4422                separator++;
4423        }
4424        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4425                show_dirstat(options);
4426
4427        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4428                for (i = 0; i < q->nr; i++) {
4429                        diff_summary(options, q->queue[i]);
4430                }
4431                separator++;
4432        }
4433
4434        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4435            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4436            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4437                /*
4438                 * run diff_flush_patch for the exit status. setting
4439                 * options->file to /dev/null should be safe, becaue we
4440                 * aren't supposed to produce any output anyway.
4441                 */
4442                if (options->close_file)
4443                        fclose(options->file);
4444                options->file = fopen("/dev/null", "w");
4445                if (!options->file)
4446                        die_errno("Could not open /dev/null");
4447                options->close_file = 1;
4448                for (i = 0; i < q->nr; i++) {
4449                        struct diff_filepair *p = q->queue[i];
4450                        if (check_pair_status(p))
4451                                diff_flush_patch(p, options);
4452                        if (options->found_changes)
4453                                break;
4454                }
4455        }
4456
4457        if (output_format & DIFF_FORMAT_PATCH) {
4458                if (separator) {
4459                        fprintf(options->file, "%s%c",
4460                                diff_line_prefix(options),
4461                                options->line_termination);
4462                        if (options->stat_sep) {
4463                                /* attach patch instead of inline */
4464                                fputs(options->stat_sep, options->file);
4465                        }
4466                }
4467
4468                for (i = 0; i < q->nr; i++) {
4469                        struct diff_filepair *p = q->queue[i];
4470                        if (check_pair_status(p))
4471                                diff_flush_patch(p, options);
4472                }
4473        }
4474
4475        if (output_format & DIFF_FORMAT_CALLBACK)
4476                options->format_callback(q, options, options->format_callback_data);
4477
4478        for (i = 0; i < q->nr; i++)
4479                diff_free_filepair(q->queue[i]);
4480free_queue:
4481        free(q->queue);
4482        DIFF_QUEUE_CLEAR(q);
4483        if (options->close_file)
4484                fclose(options->file);
4485
4486        /*
4487         * Report the content-level differences with HAS_CHANGES;
4488         * diff_addremove/diff_change does not set the bit when
4489         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4490         */
4491        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4492                if (options->found_changes)
4493                        DIFF_OPT_SET(options, HAS_CHANGES);
4494                else
4495                        DIFF_OPT_CLR(options, HAS_CHANGES);
4496        }
4497}
4498
4499static void diffcore_apply_filter(const char *filter)
4500{
4501        int i;
4502        struct diff_queue_struct *q = &diff_queued_diff;
4503        struct diff_queue_struct outq;
4504        DIFF_QUEUE_CLEAR(&outq);
4505
4506        if (!filter)
4507                return;
4508
4509        if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
4510                int found;
4511                for (i = found = 0; !found && i < q->nr; i++) {
4512                        struct diff_filepair *p = q->queue[i];
4513                        if (((p->status == DIFF_STATUS_MODIFIED) &&
4514                             ((p->score &&
4515                               strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4516                              (!p->score &&
4517                               strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4518                            ((p->status != DIFF_STATUS_MODIFIED) &&
4519                             strchr(filter, p->status)))
4520                                found++;
4521                }
4522                if (found)
4523                        return;
4524
4525                /* otherwise we will clear the whole queue
4526                 * by copying the empty outq at the end of this
4527                 * function, but first clear the current entries
4528                 * in the queue.
4529                 */
4530                for (i = 0; i < q->nr; i++)
4531                        diff_free_filepair(q->queue[i]);
4532        }
4533        else {
4534                /* Only the matching ones */
4535                for (i = 0; i < q->nr; i++) {
4536                        struct diff_filepair *p = q->queue[i];
4537
4538                        if (((p->status == DIFF_STATUS_MODIFIED) &&
4539                             ((p->score &&
4540                               strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4541                              (!p->score &&
4542                               strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4543                            ((p->status != DIFF_STATUS_MODIFIED) &&
4544                             strchr(filter, p->status)))
4545                                diff_q(&outq, p);
4546                        else
4547                                diff_free_filepair(p);
4548                }
4549        }
4550        free(q->queue);
4551        *q = outq;
4552}
4553
4554/* Check whether two filespecs with the same mode and size are identical */
4555static int diff_filespec_is_identical(struct diff_filespec *one,
4556                                      struct diff_filespec *two)
4557{
4558        if (S_ISGITLINK(one->mode))
4559                return 0;
4560        if (diff_populate_filespec(one, 0))
4561                return 0;
4562        if (diff_populate_filespec(two, 0))
4563                return 0;
4564        return !memcmp(one->data, two->data, one->size);
4565}
4566
4567static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4568{
4569        int i;
4570        struct diff_queue_struct *q = &diff_queued_diff;
4571        struct diff_queue_struct outq;
4572        DIFF_QUEUE_CLEAR(&outq);
4573
4574        for (i = 0; i < q->nr; i++) {
4575                struct diff_filepair *p = q->queue[i];
4576
4577                /*
4578                 * 1. Entries that come from stat info dirtiness
4579                 *    always have both sides (iow, not create/delete),
4580                 *    one side of the object name is unknown, with
4581                 *    the same mode and size.  Keep the ones that
4582                 *    do not match these criteria.  They have real
4583                 *    differences.
4584                 *
4585                 * 2. At this point, the file is known to be modified,
4586                 *    with the same mode and size, and the object
4587                 *    name of one side is unknown.  Need to inspect
4588                 *    the identical contents.
4589                 */
4590                if (!DIFF_FILE_VALID(p->one) || /* (1) */
4591                    !DIFF_FILE_VALID(p->two) ||
4592                    (p->one->sha1_valid && p->two->sha1_valid) ||
4593                    (p->one->mode != p->two->mode) ||
4594                    diff_populate_filespec(p->one, 1) ||
4595                    diff_populate_filespec(p->two, 1) ||
4596                    (p->one->size != p->two->size) ||
4597                    !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4598                        diff_q(&outq, p);
4599                else {
4600                        /*
4601                         * The caller can subtract 1 from skip_stat_unmatch
4602                         * to determine how many paths were dirty only
4603                         * due to stat info mismatch.
4604                         */
4605                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4606                                diffopt->skip_stat_unmatch++;
4607                        diff_free_filepair(p);
4608                }
4609        }
4610        free(q->queue);
4611        *q = outq;
4612}
4613
4614static int diffnamecmp(const void *a_, const void *b_)
4615{
4616        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4617        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4618        const char *name_a, *name_b;
4619
4620        name_a = a->one ? a->one->path : a->two->path;
4621        name_b = b->one ? b->one->path : b->two->path;
4622        return strcmp(name_a, name_b);
4623}
4624
4625void diffcore_fix_diff_index(struct diff_options *options)
4626{
4627        struct diff_queue_struct *q = &diff_queued_diff;
4628        qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4629}
4630
4631void diffcore_std(struct diff_options *options)
4632{
4633        if (options->skip_stat_unmatch)
4634                diffcore_skip_stat_unmatch(options);
4635        if (!options->found_follow) {
4636                /* See try_to_follow_renames() in tree-diff.c */
4637                if (options->break_opt != -1)
4638                        diffcore_break(options->break_opt);
4639                if (options->detect_rename)
4640                        diffcore_rename(options);
4641                if (options->break_opt != -1)
4642                        diffcore_merge_broken();
4643        }
4644        if (options->pickaxe)
4645                diffcore_pickaxe(options);
4646        if (options->orderfile)
4647                diffcore_order(options->orderfile);
4648        if (!options->found_follow)
4649                /* See try_to_follow_renames() in tree-diff.c */
4650                diff_resolve_rename_copy();
4651        diffcore_apply_filter(options->filter);
4652
4653        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4654                DIFF_OPT_SET(options, HAS_CHANGES);
4655        else
4656                DIFF_OPT_CLR(options, HAS_CHANGES);
4657
4658        options->found_follow = 0;
4659}
4660
4661int diff_result_code(struct diff_options *opt, int status)
4662{
4663        int result = 0;
4664
4665        diff_warn_rename_limit("diff.renameLimit",
4666                               opt->needed_rename_limit,
4667                               opt->degraded_cc_to_c);
4668        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4669            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4670                return status;
4671        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4672            DIFF_OPT_TST(opt, HAS_CHANGES))
4673                result |= 01;
4674        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4675            DIFF_OPT_TST(opt, CHECK_FAILED))
4676                result |= 02;
4677        return result;
4678}
4679
4680int diff_can_quit_early(struct diff_options *opt)
4681{
4682        return (DIFF_OPT_TST(opt, QUICK) &&
4683                !opt->filter &&
4684                DIFF_OPT_TST(opt, HAS_CHANGES));
4685}
4686
4687/*
4688 * Shall changes to this submodule be ignored?
4689 *
4690 * Submodule changes can be configured to be ignored separately for each path,
4691 * but that configuration can be overridden from the command line.
4692 */
4693static int is_submodule_ignored(const char *path, struct diff_options *options)
4694{
4695        int ignored = 0;
4696        unsigned orig_flags = options->flags;
4697        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4698                set_diffopt_flags_from_submodule_config(options, path);
4699        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4700                ignored = 1;
4701        options->flags = orig_flags;
4702        return ignored;
4703}
4704
4705void diff_addremove(struct diff_options *options,
4706                    int addremove, unsigned mode,
4707                    const unsigned char *sha1,
4708                    int sha1_valid,
4709                    const char *concatpath, unsigned dirty_submodule)
4710{
4711        struct diff_filespec *one, *two;
4712
4713        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4714                return;
4715
4716        /* This may look odd, but it is a preparation for
4717         * feeding "there are unchanged files which should
4718         * not produce diffs, but when you are doing copy
4719         * detection you would need them, so here they are"
4720         * entries to the diff-core.  They will be prefixed
4721         * with something like '=' or '*' (I haven't decided
4722         * which but should not make any difference).
4723         * Feeding the same new and old to diff_change()
4724         * also has the same effect.
4725         * Before the final output happens, they are pruned after
4726         * merged into rename/copy pairs as appropriate.
4727         */
4728        if (DIFF_OPT_TST(options, REVERSE_DIFF))
4729                addremove = (addremove == '+' ? '-' :
4730                             addremove == '-' ? '+' : addremove);
4731
4732        if (options->prefix &&
4733            strncmp(concatpath, options->prefix, options->prefix_length))
4734                return;
4735
4736        one = alloc_filespec(concatpath);
4737        two = alloc_filespec(concatpath);
4738
4739        if (addremove != '+')
4740                fill_filespec(one, sha1, sha1_valid, mode);
4741        if (addremove != '-') {
4742                fill_filespec(two, sha1, sha1_valid, mode);
4743                two->dirty_submodule = dirty_submodule;
4744        }
4745
4746        diff_queue(&diff_queued_diff, one, two);
4747        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4748                DIFF_OPT_SET(options, HAS_CHANGES);
4749}
4750
4751void diff_change(struct diff_options *options,
4752                 unsigned old_mode, unsigned new_mode,
4753                 const unsigned char *old_sha1,
4754                 const unsigned char *new_sha1,
4755                 int old_sha1_valid, int new_sha1_valid,
4756                 const char *concatpath,
4757                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4758{
4759        struct diff_filespec *one, *two;
4760
4761        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4762            is_submodule_ignored(concatpath, options))
4763                return;
4764
4765        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4766                unsigned tmp;
4767                const unsigned char *tmp_c;
4768                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
4769                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
4770                tmp = old_sha1_valid; old_sha1_valid = new_sha1_valid;
4771                        new_sha1_valid = tmp;
4772                tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
4773                        new_dirty_submodule = tmp;
4774        }
4775
4776        if (options->prefix &&
4777            strncmp(concatpath, options->prefix, options->prefix_length))
4778                return;
4779
4780        one = alloc_filespec(concatpath);
4781        two = alloc_filespec(concatpath);
4782        fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
4783        fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
4784        one->dirty_submodule = old_dirty_submodule;
4785        two->dirty_submodule = new_dirty_submodule;
4786
4787        diff_queue(&diff_queued_diff, one, two);
4788        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4789                DIFF_OPT_SET(options, HAS_CHANGES);
4790}
4791
4792struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
4793{
4794        struct diff_filepair *pair;
4795        struct diff_filespec *one, *two;
4796
4797        if (options->prefix &&
4798            strncmp(path, options->prefix, options->prefix_length))
4799                return NULL;
4800
4801        one = alloc_filespec(path);
4802        two = alloc_filespec(path);
4803        pair = diff_queue(&diff_queued_diff, one, two);
4804        pair->is_unmerged = 1;
4805        return pair;
4806}
4807
4808static char *run_textconv(const char *pgm, struct diff_filespec *spec,
4809                size_t *outsize)
4810{
4811        struct diff_tempfile *temp;
4812        const char *argv[3];
4813        const char **arg = argv;
4814        struct child_process child;
4815        struct strbuf buf = STRBUF_INIT;
4816        int err = 0;
4817
4818        temp = prepare_temp_file(spec->path, spec);
4819        *arg++ = pgm;
4820        *arg++ = temp->name;
4821        *arg = NULL;
4822
4823        memset(&child, 0, sizeof(child));
4824        child.use_shell = 1;
4825        child.argv = argv;
4826        child.out = -1;
4827        if (start_command(&child)) {
4828                remove_tempfile();
4829                return NULL;
4830        }
4831
4832        if (strbuf_read(&buf, child.out, 0) < 0)
4833                err = error("error reading from textconv command '%s'", pgm);
4834        close(child.out);
4835
4836        if (finish_command(&child) || err) {
4837                strbuf_release(&buf);
4838                remove_tempfile();
4839                return NULL;
4840        }
4841        remove_tempfile();
4842
4843        return strbuf_detach(&buf, outsize);
4844}
4845
4846size_t fill_textconv(struct userdiff_driver *driver,
4847                     struct diff_filespec *df,
4848                     char **outbuf)
4849{
4850        size_t size;
4851
4852        if (!driver || !driver->textconv) {
4853                if (!DIFF_FILE_VALID(df)) {
4854                        *outbuf = "";
4855                        return 0;
4856                }
4857                if (diff_populate_filespec(df, 0))
4858                        die("unable to read files to diff");
4859                *outbuf = df->data;
4860                return df->size;
4861        }
4862
4863        if (driver->textconv_cache && df->sha1_valid) {
4864                *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
4865                                          &size);
4866                if (*outbuf)
4867                        return size;
4868        }
4869
4870        *outbuf = run_textconv(driver->textconv, df, &size);
4871        if (!*outbuf)
4872                die("unable to read files to diff");
4873
4874        if (driver->textconv_cache && df->sha1_valid) {
4875                /* ignore errors, as we might be in a readonly repository */
4876                notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
4877                                size);
4878                /*
4879                 * we could save up changes and flush them all at the end,
4880                 * but we would need an extra call after all diffing is done.
4881                 * Since generating a cache entry is the slow path anyway,
4882                 * this extra overhead probably isn't a big deal.
4883                 */
4884                notes_cache_write(driver->textconv_cache);
4885        }
4886
4887        return size;
4888}
4889
4890void setup_diff_pager(struct diff_options *opt)
4891{
4892        /*
4893         * If the user asked for our exit code, then either they want --quiet
4894         * or --exit-code. We should definitely not bother with a pager in the
4895         * former case, as we will generate no output. Since we still properly
4896         * report our exit code even when a pager is run, we _could_ run a
4897         * pager with --exit-code. But since we have not done so historically,
4898         * and because it is easy to find people oneline advising "git diff
4899         * --exit-code" in hooks and other scripts, we do not do so.
4900         */
4901        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4902            check_pager_config("diff") != 0)
4903                setup_pager();
4904}