diff.con commit Merge branch 'jc/index-v4' (d4a5d87)
   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
  19#ifdef NO_FAST_WORKING_DIRECTORY
  20#define FAST_WORKING_DIRECTORY 0
  21#else
  22#define FAST_WORKING_DIRECTORY 1
  23#endif
  24
  25static int diff_detect_rename_default;
  26static int diff_rename_limit_default = 400;
  27static int diff_suppress_blank_empty;
  28int diff_use_color_default = -1;
  29static const char *diff_word_regex_cfg;
  30static const char *external_diff_cmd_cfg;
  31int diff_auto_refresh_index = 1;
  32static int diff_mnemonic_prefix;
  33static int diff_no_prefix;
  34static int diff_stat_graph_width;
  35static int diff_dirstat_permille_default = 30;
  36static struct diff_options default_diff_options;
  37
  38static char diff_colors[][COLOR_MAXLEN] = {
  39        GIT_COLOR_RESET,
  40        GIT_COLOR_NORMAL,       /* PLAIN */
  41        GIT_COLOR_BOLD,         /* METAINFO */
  42        GIT_COLOR_CYAN,         /* FRAGINFO */
  43        GIT_COLOR_RED,          /* OLD */
  44        GIT_COLOR_GREEN,        /* NEW */
  45        GIT_COLOR_YELLOW,       /* COMMIT */
  46        GIT_COLOR_BG_RED,       /* WHITESPACE */
  47        GIT_COLOR_NORMAL,       /* FUNCINFO */
  48};
  49
  50static int parse_diff_color_slot(const char *var, int ofs)
  51{
  52        if (!strcasecmp(var+ofs, "plain"))
  53                return DIFF_PLAIN;
  54        if (!strcasecmp(var+ofs, "meta"))
  55                return DIFF_METAINFO;
  56        if (!strcasecmp(var+ofs, "frag"))
  57                return DIFF_FRAGINFO;
  58        if (!strcasecmp(var+ofs, "old"))
  59                return DIFF_FILE_OLD;
  60        if (!strcasecmp(var+ofs, "new"))
  61                return DIFF_FILE_NEW;
  62        if (!strcasecmp(var+ofs, "commit"))
  63                return DIFF_COMMIT;
  64        if (!strcasecmp(var+ofs, "whitespace"))
  65                return DIFF_WHITESPACE;
  66        if (!strcasecmp(var+ofs, "func"))
  67                return DIFF_FUNCINFO;
  68        return -1;
  69}
  70
  71static int parse_dirstat_params(struct diff_options *options, const char *params,
  72                                struct strbuf *errmsg)
  73{
  74        const char *p = params;
  75        int p_len, ret = 0;
  76
  77        while (*p) {
  78                p_len = strchrnul(p, ',') - p;
  79                if (!memcmp(p, "changes", p_len)) {
  80                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  81                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  82                } else if (!memcmp(p, "lines", p_len)) {
  83                        DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
  84                        DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  85                } else if (!memcmp(p, "files", p_len)) {
  86                        DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  87                        DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
  88                } else if (!memcmp(p, "noncumulative", p_len)) {
  89                        DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
  90                } else if (!memcmp(p, "cumulative", p_len)) {
  91                        DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
  92                } else if (isdigit(*p)) {
  93                        char *end;
  94                        int permille = strtoul(p, &end, 10) * 10;
  95                        if (*end == '.' && isdigit(*++end)) {
  96                                /* only use first digit */
  97                                permille += *end - '0';
  98                                /* .. and ignore any further digits */
  99                                while (isdigit(*++end))
 100                                        ; /* nothing */
 101                        }
 102                        if (end - p == p_len)
 103                                options->dirstat_permille = permille;
 104                        else {
 105                                strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%.*s'\n"),
 106                                            p_len, p);
 107                                ret++;
 108                        }
 109                } else {
 110                        strbuf_addf(errmsg, _("  Unknown dirstat parameter '%.*s'\n"),
 111                                    p_len, p);
 112                        ret++;
 113                }
 114
 115                p += p_len;
 116
 117                if (*p)
 118                        p++; /* more parameters, swallow separator */
 119        }
 120        return ret;
 121}
 122
 123static int git_config_rename(const char *var, const char *value)
 124{
 125        if (!value)
 126                return DIFF_DETECT_RENAME;
 127        if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 128                return  DIFF_DETECT_COPY;
 129        return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 130}
 131
 132/*
 133 * These are to give UI layer defaults.
 134 * The core-level commands such as git-diff-files should
 135 * never be affected by the setting of diff.renames
 136 * the user happens to have in the configuration file.
 137 */
 138int git_diff_ui_config(const char *var, const char *value, void *cb)
 139{
 140        if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 141                diff_use_color_default = git_config_colorbool(var, value);
 142                return 0;
 143        }
 144        if (!strcmp(var, "diff.renames")) {
 145                diff_detect_rename_default = git_config_rename(var, value);
 146                return 0;
 147        }
 148        if (!strcmp(var, "diff.autorefreshindex")) {
 149                diff_auto_refresh_index = git_config_bool(var, value);
 150                return 0;
 151        }
 152        if (!strcmp(var, "diff.mnemonicprefix")) {
 153                diff_mnemonic_prefix = git_config_bool(var, value);
 154                return 0;
 155        }
 156        if (!strcmp(var, "diff.noprefix")) {
 157                diff_no_prefix = git_config_bool(var, value);
 158                return 0;
 159        }
 160        if (!strcmp(var, "diff.statgraphwidth")) {
 161                diff_stat_graph_width = git_config_int(var, value);
 162                return 0;
 163        }
 164        if (!strcmp(var, "diff.external"))
 165                return git_config_string(&external_diff_cmd_cfg, var, value);
 166        if (!strcmp(var, "diff.wordregex"))
 167                return git_config_string(&diff_word_regex_cfg, var, value);
 168
 169        if (!strcmp(var, "diff.ignoresubmodules"))
 170                handle_ignore_submodules_arg(&default_diff_options, value);
 171
 172        if (git_color_config(var, value, cb) < 0)
 173                return -1;
 174
 175        return git_diff_basic_config(var, value, cb);
 176}
 177
 178int git_diff_basic_config(const char *var, const char *value, void *cb)
 179{
 180        if (!strcmp(var, "diff.renamelimit")) {
 181                diff_rename_limit_default = git_config_int(var, value);
 182                return 0;
 183        }
 184
 185        if (userdiff_config(var, value) < 0)
 186                return -1;
 187
 188        if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
 189                int slot = parse_diff_color_slot(var, 11);
 190                if (slot < 0)
 191                        return 0;
 192                if (!value)
 193                        return config_error_nonbool(var);
 194                color_parse(value, var, diff_colors[slot]);
 195                return 0;
 196        }
 197
 198        /* like GNU diff's --suppress-blank-empty option  */
 199        if (!strcmp(var, "diff.suppressblankempty") ||
 200                        /* for backwards compatibility */
 201                        !strcmp(var, "diff.suppress-blank-empty")) {
 202                diff_suppress_blank_empty = git_config_bool(var, value);
 203                return 0;
 204        }
 205
 206        if (!strcmp(var, "diff.dirstat")) {
 207                struct strbuf errmsg = STRBUF_INIT;
 208                default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 209                if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 210                        warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 211                                errmsg.buf);
 212                strbuf_release(&errmsg);
 213                diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 214                return 0;
 215        }
 216
 217        if (!prefixcmp(var, "submodule."))
 218                return parse_submodule_config_option(var, value);
 219
 220        return git_default_config(var, value, cb);
 221}
 222
 223static char *quote_two(const char *one, const char *two)
 224{
 225        int need_one = quote_c_style(one, NULL, NULL, 1);
 226        int need_two = quote_c_style(two, NULL, NULL, 1);
 227        struct strbuf res = STRBUF_INIT;
 228
 229        if (need_one + need_two) {
 230                strbuf_addch(&res, '"');
 231                quote_c_style(one, &res, NULL, 1);
 232                quote_c_style(two, &res, NULL, 1);
 233                strbuf_addch(&res, '"');
 234        } else {
 235                strbuf_addstr(&res, one);
 236                strbuf_addstr(&res, two);
 237        }
 238        return strbuf_detach(&res, NULL);
 239}
 240
 241static const char *external_diff(void)
 242{
 243        static const char *external_diff_cmd = NULL;
 244        static int done_preparing = 0;
 245
 246        if (done_preparing)
 247                return external_diff_cmd;
 248        external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 249        if (!external_diff_cmd)
 250                external_diff_cmd = external_diff_cmd_cfg;
 251        done_preparing = 1;
 252        return external_diff_cmd;
 253}
 254
 255static struct diff_tempfile {
 256        const char *name; /* filename external diff should read from */
 257        char hex[41];
 258        char mode[10];
 259        char tmp_path[PATH_MAX];
 260} diff_temp[2];
 261
 262typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 263
 264struct emit_callback {
 265        int color_diff;
 266        unsigned ws_rule;
 267        int blank_at_eof_in_preimage;
 268        int blank_at_eof_in_postimage;
 269        int lno_in_preimage;
 270        int lno_in_postimage;
 271        sane_truncate_fn truncate;
 272        const char **label_path;
 273        struct diff_words_data *diff_words;
 274        struct diff_options *opt;
 275        int *found_changesp;
 276        struct strbuf *header;
 277};
 278
 279static int count_lines(const char *data, int size)
 280{
 281        int count, ch, completely_empty = 1, nl_just_seen = 0;
 282        count = 0;
 283        while (0 < size--) {
 284                ch = *data++;
 285                if (ch == '\n') {
 286                        count++;
 287                        nl_just_seen = 1;
 288                        completely_empty = 0;
 289                }
 290                else {
 291                        nl_just_seen = 0;
 292                        completely_empty = 0;
 293                }
 294        }
 295        if (completely_empty)
 296                return 0;
 297        if (!nl_just_seen)
 298                count++; /* no trailing newline */
 299        return count;
 300}
 301
 302static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 303{
 304        if (!DIFF_FILE_VALID(one)) {
 305                mf->ptr = (char *)""; /* does not matter */
 306                mf->size = 0;
 307                return 0;
 308        }
 309        else if (diff_populate_filespec(one, 0))
 310                return -1;
 311
 312        mf->ptr = one->data;
 313        mf->size = one->size;
 314        return 0;
 315}
 316
 317/* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 318static unsigned long diff_filespec_size(struct diff_filespec *one)
 319{
 320        if (!DIFF_FILE_VALID(one))
 321                return 0;
 322        diff_populate_filespec(one, 1);
 323        return one->size;
 324}
 325
 326static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 327{
 328        char *ptr = mf->ptr;
 329        long size = mf->size;
 330        int cnt = 0;
 331
 332        if (!size)
 333                return cnt;
 334        ptr += size - 1; /* pointing at the very end */
 335        if (*ptr != '\n')
 336                ; /* incomplete line */
 337        else
 338                ptr--; /* skip the last LF */
 339        while (mf->ptr < ptr) {
 340                char *prev_eol;
 341                for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 342                        if (*prev_eol == '\n')
 343                                break;
 344                if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 345                        break;
 346                cnt++;
 347                ptr = prev_eol - 1;
 348        }
 349        return cnt;
 350}
 351
 352static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 353                               struct emit_callback *ecbdata)
 354{
 355        int l1, l2, at;
 356        unsigned ws_rule = ecbdata->ws_rule;
 357        l1 = count_trailing_blank(mf1, ws_rule);
 358        l2 = count_trailing_blank(mf2, ws_rule);
 359        if (l2 <= l1) {
 360                ecbdata->blank_at_eof_in_preimage = 0;
 361                ecbdata->blank_at_eof_in_postimage = 0;
 362                return;
 363        }
 364        at = count_lines(mf1->ptr, mf1->size);
 365        ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 366
 367        at = count_lines(mf2->ptr, mf2->size);
 368        ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 369}
 370
 371static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 372                        int first, const char *line, int len)
 373{
 374        int has_trailing_newline, has_trailing_carriage_return;
 375        int nofirst;
 376        FILE *file = o->file;
 377
 378        if (o->output_prefix) {
 379                struct strbuf *msg = NULL;
 380                msg = o->output_prefix(o, o->output_prefix_data);
 381                assert(msg);
 382                fwrite(msg->buf, msg->len, 1, file);
 383        }
 384
 385        if (len == 0) {
 386                has_trailing_newline = (first == '\n');
 387                has_trailing_carriage_return = (!has_trailing_newline &&
 388                                                (first == '\r'));
 389                nofirst = has_trailing_newline || has_trailing_carriage_return;
 390        } else {
 391                has_trailing_newline = (len > 0 && line[len-1] == '\n');
 392                if (has_trailing_newline)
 393                        len--;
 394                has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 395                if (has_trailing_carriage_return)
 396                        len--;
 397                nofirst = 0;
 398        }
 399
 400        if (len || !nofirst) {
 401                fputs(set, file);
 402                if (!nofirst)
 403                        fputc(first, file);
 404                fwrite(line, len, 1, file);
 405                fputs(reset, file);
 406        }
 407        if (has_trailing_carriage_return)
 408                fputc('\r', file);
 409        if (has_trailing_newline)
 410                fputc('\n', file);
 411}
 412
 413static void emit_line(struct diff_options *o, const char *set, const char *reset,
 414                      const char *line, int len)
 415{
 416        emit_line_0(o, set, reset, line[0], line+1, len-1);
 417}
 418
 419static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 420{
 421        if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 422              ecbdata->blank_at_eof_in_preimage &&
 423              ecbdata->blank_at_eof_in_postimage &&
 424              ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 425              ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 426                return 0;
 427        return ws_blank_line(line, len, ecbdata->ws_rule);
 428}
 429
 430static void emit_add_line(const char *reset,
 431                          struct emit_callback *ecbdata,
 432                          const char *line, int len)
 433{
 434        const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 435        const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 436
 437        if (!*ws)
 438                emit_line_0(ecbdata->opt, set, reset, '+', line, len);
 439        else if (new_blank_line_at_eof(ecbdata, line, len))
 440                /* Blank line at EOF - paint '+' as well */
 441                emit_line_0(ecbdata->opt, ws, reset, '+', line, len);
 442        else {
 443                /* Emit just the prefix, then the rest. */
 444                emit_line_0(ecbdata->opt, set, reset, '+', "", 0);
 445                ws_check_emit(line, len, ecbdata->ws_rule,
 446                              ecbdata->opt->file, set, reset, ws);
 447        }
 448}
 449
 450static void emit_hunk_header(struct emit_callback *ecbdata,
 451                             const char *line, int len)
 452{
 453        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
 454        const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 455        const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 456        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 457        static const char atat[2] = { '@', '@' };
 458        const char *cp, *ep;
 459        struct strbuf msgbuf = STRBUF_INIT;
 460        int org_len = len;
 461        int i = 1;
 462
 463        /*
 464         * As a hunk header must begin with "@@ -<old>, +<new> @@",
 465         * it always is at least 10 bytes long.
 466         */
 467        if (len < 10 ||
 468            memcmp(line, atat, 2) ||
 469            !(ep = memmem(line + 2, len - 2, atat, 2))) {
 470                emit_line(ecbdata->opt, plain, reset, line, len);
 471                return;
 472        }
 473        ep += 2; /* skip over @@ */
 474
 475        /* The hunk header in fraginfo color */
 476        strbuf_add(&msgbuf, frag, strlen(frag));
 477        strbuf_add(&msgbuf, line, ep - line);
 478        strbuf_add(&msgbuf, reset, strlen(reset));
 479
 480        /*
 481         * trailing "\r\n"
 482         */
 483        for ( ; i < 3; i++)
 484                if (line[len - i] == '\r' || line[len - i] == '\n')
 485                        len--;
 486
 487        /* blank before the func header */
 488        for (cp = ep; ep - line < len; ep++)
 489                if (*ep != ' ' && *ep != '\t')
 490                        break;
 491        if (ep != cp) {
 492                strbuf_add(&msgbuf, plain, strlen(plain));
 493                strbuf_add(&msgbuf, cp, ep - cp);
 494                strbuf_add(&msgbuf, reset, strlen(reset));
 495        }
 496
 497        if (ep < line + len) {
 498                strbuf_add(&msgbuf, func, strlen(func));
 499                strbuf_add(&msgbuf, ep, line + len - ep);
 500                strbuf_add(&msgbuf, reset, strlen(reset));
 501        }
 502
 503        strbuf_add(&msgbuf, line + len, org_len - len);
 504        emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 505        strbuf_release(&msgbuf);
 506}
 507
 508static struct diff_tempfile *claim_diff_tempfile(void) {
 509        int i;
 510        for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 511                if (!diff_temp[i].name)
 512                        return diff_temp + i;
 513        die("BUG: diff is failing to clean up its tempfiles");
 514}
 515
 516static int remove_tempfile_installed;
 517
 518static void remove_tempfile(void)
 519{
 520        int i;
 521        for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 522                if (diff_temp[i].name == diff_temp[i].tmp_path)
 523                        unlink_or_warn(diff_temp[i].name);
 524                diff_temp[i].name = NULL;
 525        }
 526}
 527
 528static void remove_tempfile_on_signal(int signo)
 529{
 530        remove_tempfile();
 531        sigchain_pop(signo);
 532        raise(signo);
 533}
 534
 535static void print_line_count(FILE *file, int count)
 536{
 537        switch (count) {
 538        case 0:
 539                fprintf(file, "0,0");
 540                break;
 541        case 1:
 542                fprintf(file, "1");
 543                break;
 544        default:
 545                fprintf(file, "1,%d", count);
 546                break;
 547        }
 548}
 549
 550static void emit_rewrite_lines(struct emit_callback *ecb,
 551                               int prefix, const char *data, int size)
 552{
 553        const char *endp = NULL;
 554        static const char *nneof = " No newline at end of file\n";
 555        const char *old = diff_get_color(ecb->color_diff, DIFF_FILE_OLD);
 556        const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 557
 558        while (0 < size) {
 559                int len;
 560
 561                endp = memchr(data, '\n', size);
 562                len = endp ? (endp - data + 1) : size;
 563                if (prefix != '+') {
 564                        ecb->lno_in_preimage++;
 565                        emit_line_0(ecb->opt, old, reset, '-',
 566                                    data, len);
 567                } else {
 568                        ecb->lno_in_postimage++;
 569                        emit_add_line(reset, ecb, data, len);
 570                }
 571                size -= len;
 572                data += len;
 573        }
 574        if (!endp) {
 575                const char *plain = diff_get_color(ecb->color_diff,
 576                                                   DIFF_PLAIN);
 577                emit_line_0(ecb->opt, plain, reset, '\\',
 578                            nneof, strlen(nneof));
 579        }
 580}
 581
 582static void emit_rewrite_diff(const char *name_a,
 583                              const char *name_b,
 584                              struct diff_filespec *one,
 585                              struct diff_filespec *two,
 586                              struct userdiff_driver *textconv_one,
 587                              struct userdiff_driver *textconv_two,
 588                              struct diff_options *o)
 589{
 590        int lc_a, lc_b;
 591        const char *name_a_tab, *name_b_tab;
 592        const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 593        const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 594        const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 595        static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 596        const char *a_prefix, *b_prefix;
 597        char *data_one, *data_two;
 598        size_t size_one, size_two;
 599        struct emit_callback ecbdata;
 600        char *line_prefix = "";
 601        struct strbuf *msgbuf;
 602
 603        if (o && o->output_prefix) {
 604                msgbuf = o->output_prefix(o, o->output_prefix_data);
 605                line_prefix = msgbuf->buf;
 606        }
 607
 608        if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 609                a_prefix = o->b_prefix;
 610                b_prefix = o->a_prefix;
 611        } else {
 612                a_prefix = o->a_prefix;
 613                b_prefix = o->b_prefix;
 614        }
 615
 616        name_a += (*name_a == '/');
 617        name_b += (*name_b == '/');
 618        name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 619        name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 620
 621        strbuf_reset(&a_name);
 622        strbuf_reset(&b_name);
 623        quote_two_c_style(&a_name, a_prefix, name_a, 0);
 624        quote_two_c_style(&b_name, b_prefix, name_b, 0);
 625
 626        size_one = fill_textconv(textconv_one, one, &data_one);
 627        size_two = fill_textconv(textconv_two, two, &data_two);
 628
 629        memset(&ecbdata, 0, sizeof(ecbdata));
 630        ecbdata.color_diff = want_color(o->use_color);
 631        ecbdata.found_changesp = &o->found_changes;
 632        ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
 633        ecbdata.opt = o;
 634        if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 635                mmfile_t mf1, mf2;
 636                mf1.ptr = (char *)data_one;
 637                mf2.ptr = (char *)data_two;
 638                mf1.size = size_one;
 639                mf2.size = size_two;
 640                check_blank_at_eof(&mf1, &mf2, &ecbdata);
 641        }
 642        ecbdata.lno_in_preimage = 1;
 643        ecbdata.lno_in_postimage = 1;
 644
 645        lc_a = count_lines(data_one, size_one);
 646        lc_b = count_lines(data_two, size_two);
 647        fprintf(o->file,
 648                "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 649                line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 650                line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 651                line_prefix, fraginfo);
 652        if (!o->irreversible_delete)
 653                print_line_count(o->file, lc_a);
 654        else
 655                fprintf(o->file, "?,?");
 656        fprintf(o->file, " +");
 657        print_line_count(o->file, lc_b);
 658        fprintf(o->file, " @@%s\n", reset);
 659        if (lc_a && !o->irreversible_delete)
 660                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 661        if (lc_b)
 662                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 663        if (textconv_one)
 664                free((char *)data_one);
 665        if (textconv_two)
 666                free((char *)data_two);
 667}
 668
 669struct diff_words_buffer {
 670        mmfile_t text;
 671        long alloc;
 672        struct diff_words_orig {
 673                const char *begin, *end;
 674        } *orig;
 675        int orig_nr, orig_alloc;
 676};
 677
 678static void diff_words_append(char *line, unsigned long len,
 679                struct diff_words_buffer *buffer)
 680{
 681        ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 682        line++;
 683        len--;
 684        memcpy(buffer->text.ptr + buffer->text.size, line, len);
 685        buffer->text.size += len;
 686        buffer->text.ptr[buffer->text.size] = '\0';
 687}
 688
 689struct diff_words_style_elem {
 690        const char *prefix;
 691        const char *suffix;
 692        const char *color; /* NULL; filled in by the setup code if
 693                            * color is enabled */
 694};
 695
 696struct diff_words_style {
 697        enum diff_words_type type;
 698        struct diff_words_style_elem new, old, ctx;
 699        const char *newline;
 700};
 701
 702static struct diff_words_style diff_words_styles[] = {
 703        { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 704        { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 705        { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 706};
 707
 708struct diff_words_data {
 709        struct diff_words_buffer minus, plus;
 710        const char *current_plus;
 711        int last_minus;
 712        struct diff_options *opt;
 713        regex_t *word_regex;
 714        enum diff_words_type type;
 715        struct diff_words_style *style;
 716};
 717
 718static int fn_out_diff_words_write_helper(FILE *fp,
 719                                          struct diff_words_style_elem *st_el,
 720                                          const char *newline,
 721                                          size_t count, const char *buf,
 722                                          const char *line_prefix)
 723{
 724        int print = 0;
 725
 726        while (count) {
 727                char *p = memchr(buf, '\n', count);
 728                if (print)
 729                        fputs(line_prefix, fp);
 730                if (p != buf) {
 731                        if (st_el->color && fputs(st_el->color, fp) < 0)
 732                                return -1;
 733                        if (fputs(st_el->prefix, fp) < 0 ||
 734                            fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 735                            fputs(st_el->suffix, fp) < 0)
 736                                return -1;
 737                        if (st_el->color && *st_el->color
 738                            && fputs(GIT_COLOR_RESET, fp) < 0)
 739                                return -1;
 740                }
 741                if (!p)
 742                        return 0;
 743                if (fputs(newline, fp) < 0)
 744                        return -1;
 745                count -= p + 1 - buf;
 746                buf = p + 1;
 747                print = 1;
 748        }
 749        return 0;
 750}
 751
 752/*
 753 * '--color-words' algorithm can be described as:
 754 *
 755 *   1. collect a the minus/plus lines of a diff hunk, divided into
 756 *      minus-lines and plus-lines;
 757 *
 758 *   2. break both minus-lines and plus-lines into words and
 759 *      place them into two mmfile_t with one word for each line;
 760 *
 761 *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 762 *
 763 * And for the common parts of the both file, we output the plus side text.
 764 * diff_words->current_plus is used to trace the current position of the plus file
 765 * which printed. diff_words->last_minus is used to trace the last minus word
 766 * printed.
 767 *
 768 * For '--graph' to work with '--color-words', we need to output the graph prefix
 769 * on each line of color words output. Generally, there are two conditions on
 770 * which we should output the prefix.
 771 *
 772 *   1. diff_words->last_minus == 0 &&
 773 *      diff_words->current_plus == diff_words->plus.text.ptr
 774 *
 775 *      that is: the plus text must start as a new line, and if there is no minus
 776 *      word printed, a graph prefix must be printed.
 777 *
 778 *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 779 *      *(diff_words->current_plus - 1) == '\n'
 780 *
 781 *      that is: a graph prefix must be printed following a '\n'
 782 */
 783static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 784{
 785        if ((diff_words->last_minus == 0 &&
 786                diff_words->current_plus == diff_words->plus.text.ptr) ||
 787                (diff_words->current_plus > diff_words->plus.text.ptr &&
 788                *(diff_words->current_plus - 1) == '\n')) {
 789                return 1;
 790        } else {
 791                return 0;
 792        }
 793}
 794
 795static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 796{
 797        struct diff_words_data *diff_words = priv;
 798        struct diff_words_style *style = diff_words->style;
 799        int minus_first, minus_len, plus_first, plus_len;
 800        const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 801        struct diff_options *opt = diff_words->opt;
 802        struct strbuf *msgbuf;
 803        char *line_prefix = "";
 804
 805        if (line[0] != '@' || parse_hunk_header(line, len,
 806                        &minus_first, &minus_len, &plus_first, &plus_len))
 807                return;
 808
 809        assert(opt);
 810        if (opt->output_prefix) {
 811                msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
 812                line_prefix = msgbuf->buf;
 813        }
 814
 815        /* POSIX requires that first be decremented by one if len == 0... */
 816        if (minus_len) {
 817                minus_begin = diff_words->minus.orig[minus_first].begin;
 818                minus_end =
 819                        diff_words->minus.orig[minus_first + minus_len - 1].end;
 820        } else
 821                minus_begin = minus_end =
 822                        diff_words->minus.orig[minus_first].end;
 823
 824        if (plus_len) {
 825                plus_begin = diff_words->plus.orig[plus_first].begin;
 826                plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 827        } else
 828                plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 829
 830        if (color_words_output_graph_prefix(diff_words)) {
 831                fputs(line_prefix, diff_words->opt->file);
 832        }
 833        if (diff_words->current_plus != plus_begin) {
 834                fn_out_diff_words_write_helper(diff_words->opt->file,
 835                                &style->ctx, style->newline,
 836                                plus_begin - diff_words->current_plus,
 837                                diff_words->current_plus, line_prefix);
 838                if (*(plus_begin - 1) == '\n')
 839                        fputs(line_prefix, diff_words->opt->file);
 840        }
 841        if (minus_begin != minus_end) {
 842                fn_out_diff_words_write_helper(diff_words->opt->file,
 843                                &style->old, style->newline,
 844                                minus_end - minus_begin, minus_begin,
 845                                line_prefix);
 846        }
 847        if (plus_begin != plus_end) {
 848                fn_out_diff_words_write_helper(diff_words->opt->file,
 849                                &style->new, style->newline,
 850                                plus_end - plus_begin, plus_begin,
 851                                line_prefix);
 852        }
 853
 854        diff_words->current_plus = plus_end;
 855        diff_words->last_minus = minus_first;
 856}
 857
 858/* This function starts looking at *begin, and returns 0 iff a word was found. */
 859static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 860                int *begin, int *end)
 861{
 862        if (word_regex && *begin < buffer->size) {
 863                regmatch_t match[1];
 864                if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 865                        char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 866                                        '\n', match[0].rm_eo - match[0].rm_so);
 867                        *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 868                        *begin += match[0].rm_so;
 869                        return *begin >= *end;
 870                }
 871                return -1;
 872        }
 873
 874        /* find the next word */
 875        while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 876                (*begin)++;
 877        if (*begin >= buffer->size)
 878                return -1;
 879
 880        /* find the end of the word */
 881        *end = *begin + 1;
 882        while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 883                (*end)++;
 884
 885        return 0;
 886}
 887
 888/*
 889 * This function splits the words in buffer->text, stores the list with
 890 * newline separator into out, and saves the offsets of the original words
 891 * in buffer->orig.
 892 */
 893static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 894                regex_t *word_regex)
 895{
 896        int i, j;
 897        long alloc = 0;
 898
 899        out->size = 0;
 900        out->ptr = NULL;
 901
 902        /* fake an empty "0th" word */
 903        ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 904        buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 905        buffer->orig_nr = 1;
 906
 907        for (i = 0; i < buffer->text.size; i++) {
 908                if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 909                        return;
 910
 911                /* store original boundaries */
 912                ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
 913                                buffer->orig_alloc);
 914                buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
 915                buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
 916                buffer->orig_nr++;
 917
 918                /* store one word */
 919                ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
 920                memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
 921                out->ptr[out->size + j - i] = '\n';
 922                out->size += j - i + 1;
 923
 924                i = j - 1;
 925        }
 926}
 927
 928/* this executes the word diff on the accumulated buffers */
 929static void diff_words_show(struct diff_words_data *diff_words)
 930{
 931        xpparam_t xpp;
 932        xdemitconf_t xecfg;
 933        mmfile_t minus, plus;
 934        struct diff_words_style *style = diff_words->style;
 935
 936        struct diff_options *opt = diff_words->opt;
 937        struct strbuf *msgbuf;
 938        char *line_prefix = "";
 939
 940        assert(opt);
 941        if (opt->output_prefix) {
 942                msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
 943                line_prefix = msgbuf->buf;
 944        }
 945
 946        /* special case: only removal */
 947        if (!diff_words->plus.text.size) {
 948                fputs(line_prefix, diff_words->opt->file);
 949                fn_out_diff_words_write_helper(diff_words->opt->file,
 950                        &style->old, style->newline,
 951                        diff_words->minus.text.size,
 952                        diff_words->minus.text.ptr, line_prefix);
 953                diff_words->minus.text.size = 0;
 954                return;
 955        }
 956
 957        diff_words->current_plus = diff_words->plus.text.ptr;
 958        diff_words->last_minus = 0;
 959
 960        memset(&xpp, 0, sizeof(xpp));
 961        memset(&xecfg, 0, sizeof(xecfg));
 962        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
 963        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
 964        xpp.flags = 0;
 965        /* as only the hunk header will be parsed, we need a 0-context */
 966        xecfg.ctxlen = 0;
 967        xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
 968                      &xpp, &xecfg);
 969        free(minus.ptr);
 970        free(plus.ptr);
 971        if (diff_words->current_plus != diff_words->plus.text.ptr +
 972                        diff_words->plus.text.size) {
 973                if (color_words_output_graph_prefix(diff_words))
 974                        fputs(line_prefix, diff_words->opt->file);
 975                fn_out_diff_words_write_helper(diff_words->opt->file,
 976                        &style->ctx, style->newline,
 977                        diff_words->plus.text.ptr + diff_words->plus.text.size
 978                        - diff_words->current_plus, diff_words->current_plus,
 979                        line_prefix);
 980        }
 981        diff_words->minus.text.size = diff_words->plus.text.size = 0;
 982}
 983
 984/* In "color-words" mode, show word-diff of words accumulated in the buffer */
 985static void diff_words_flush(struct emit_callback *ecbdata)
 986{
 987        if (ecbdata->diff_words->minus.text.size ||
 988            ecbdata->diff_words->plus.text.size)
 989                diff_words_show(ecbdata->diff_words);
 990}
 991
 992static void diff_filespec_load_driver(struct diff_filespec *one)
 993{
 994        /* Use already-loaded driver */
 995        if (one->driver)
 996                return;
 997
 998        if (S_ISREG(one->mode))
 999                one->driver = userdiff_find_by_path(one->path);
1000
1001        /* Fallback to default settings */
1002        if (!one->driver)
1003                one->driver = userdiff_find_by_name("default");
1004}
1005
1006static const char *userdiff_word_regex(struct diff_filespec *one)
1007{
1008        diff_filespec_load_driver(one);
1009        return one->driver->word_regex;
1010}
1011
1012static void init_diff_words_data(struct emit_callback *ecbdata,
1013                                 struct diff_options *orig_opts,
1014                                 struct diff_filespec *one,
1015                                 struct diff_filespec *two)
1016{
1017        int i;
1018        struct diff_options *o = xmalloc(sizeof(struct diff_options));
1019        memcpy(o, orig_opts, sizeof(struct diff_options));
1020
1021        ecbdata->diff_words =
1022                xcalloc(1, sizeof(struct diff_words_data));
1023        ecbdata->diff_words->type = o->word_diff;
1024        ecbdata->diff_words->opt = o;
1025        if (!o->word_regex)
1026                o->word_regex = userdiff_word_regex(one);
1027        if (!o->word_regex)
1028                o->word_regex = userdiff_word_regex(two);
1029        if (!o->word_regex)
1030                o->word_regex = diff_word_regex_cfg;
1031        if (o->word_regex) {
1032                ecbdata->diff_words->word_regex = (regex_t *)
1033                        xmalloc(sizeof(regex_t));
1034                if (regcomp(ecbdata->diff_words->word_regex,
1035                            o->word_regex,
1036                            REG_EXTENDED | REG_NEWLINE))
1037                        die ("Invalid regular expression: %s",
1038                             o->word_regex);
1039        }
1040        for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1041                if (o->word_diff == diff_words_styles[i].type) {
1042                        ecbdata->diff_words->style =
1043                                &diff_words_styles[i];
1044                        break;
1045                }
1046        }
1047        if (want_color(o->use_color)) {
1048                struct diff_words_style *st = ecbdata->diff_words->style;
1049                st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1050                st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1051                st->ctx.color = diff_get_color_opt(o, DIFF_PLAIN);
1052        }
1053}
1054
1055static void free_diff_words_data(struct emit_callback *ecbdata)
1056{
1057        if (ecbdata->diff_words) {
1058                diff_words_flush(ecbdata);
1059                free (ecbdata->diff_words->opt);
1060                free (ecbdata->diff_words->minus.text.ptr);
1061                free (ecbdata->diff_words->minus.orig);
1062                free (ecbdata->diff_words->plus.text.ptr);
1063                free (ecbdata->diff_words->plus.orig);
1064                if (ecbdata->diff_words->word_regex) {
1065                        regfree(ecbdata->diff_words->word_regex);
1066                        free(ecbdata->diff_words->word_regex);
1067                }
1068                free(ecbdata->diff_words);
1069                ecbdata->diff_words = NULL;
1070        }
1071}
1072
1073const char *diff_get_color(int diff_use_color, enum color_diff ix)
1074{
1075        if (want_color(diff_use_color))
1076                return diff_colors[ix];
1077        return "";
1078}
1079
1080static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1081{
1082        const char *cp;
1083        unsigned long allot;
1084        size_t l = len;
1085
1086        if (ecb->truncate)
1087                return ecb->truncate(line, len);
1088        cp = line;
1089        allot = l;
1090        while (0 < l) {
1091                (void) utf8_width(&cp, &l);
1092                if (!cp)
1093                        break; /* truncated in the middle? */
1094        }
1095        return allot - l;
1096}
1097
1098static void find_lno(const char *line, struct emit_callback *ecbdata)
1099{
1100        const char *p;
1101        ecbdata->lno_in_preimage = 0;
1102        ecbdata->lno_in_postimage = 0;
1103        p = strchr(line, '-');
1104        if (!p)
1105                return; /* cannot happen */
1106        ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1107        p = strchr(p, '+');
1108        if (!p)
1109                return; /* cannot happen */
1110        ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1111}
1112
1113static void fn_out_consume(void *priv, char *line, unsigned long len)
1114{
1115        struct emit_callback *ecbdata = priv;
1116        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1117        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
1118        const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1119        struct diff_options *o = ecbdata->opt;
1120        char *line_prefix = "";
1121        struct strbuf *msgbuf;
1122
1123        if (o && o->output_prefix) {
1124                msgbuf = o->output_prefix(o, o->output_prefix_data);
1125                line_prefix = msgbuf->buf;
1126        }
1127
1128        if (ecbdata->header) {
1129                fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1130                strbuf_reset(ecbdata->header);
1131                ecbdata->header = NULL;
1132        }
1133        *(ecbdata->found_changesp) = 1;
1134
1135        if (ecbdata->label_path[0]) {
1136                const char *name_a_tab, *name_b_tab;
1137
1138                name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1139                name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1140
1141                fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1142                        line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1143                fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1144                        line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1145                ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1146        }
1147
1148        if (diff_suppress_blank_empty
1149            && len == 2 && line[0] == ' ' && line[1] == '\n') {
1150                line[0] = '\n';
1151                len = 1;
1152        }
1153
1154        if (line[0] == '@') {
1155                if (ecbdata->diff_words)
1156                        diff_words_flush(ecbdata);
1157                len = sane_truncate_line(ecbdata, line, len);
1158                find_lno(line, ecbdata);
1159                emit_hunk_header(ecbdata, line, len);
1160                if (line[len-1] != '\n')
1161                        putc('\n', ecbdata->opt->file);
1162                return;
1163        }
1164
1165        if (len < 1) {
1166                emit_line(ecbdata->opt, reset, reset, line, len);
1167                if (ecbdata->diff_words
1168                    && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1169                        fputs("~\n", ecbdata->opt->file);
1170                return;
1171        }
1172
1173        if (ecbdata->diff_words) {
1174                if (line[0] == '-') {
1175                        diff_words_append(line, len,
1176                                          &ecbdata->diff_words->minus);
1177                        return;
1178                } else if (line[0] == '+') {
1179                        diff_words_append(line, len,
1180                                          &ecbdata->diff_words->plus);
1181                        return;
1182                } else if (!prefixcmp(line, "\\ ")) {
1183                        /*
1184                         * Eat the "no newline at eof" marker as if we
1185                         * saw a "+" or "-" line with nothing on it,
1186                         * and return without diff_words_flush() to
1187                         * defer processing. If this is the end of
1188                         * preimage, more "+" lines may come after it.
1189                         */
1190                        return;
1191                }
1192                diff_words_flush(ecbdata);
1193                if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1194                        emit_line(ecbdata->opt, plain, reset, line, len);
1195                        fputs("~\n", ecbdata->opt->file);
1196                } else {
1197                        /*
1198                         * Skip the prefix character, if any.  With
1199                         * diff_suppress_blank_empty, there may be
1200                         * none.
1201                         */
1202                        if (line[0] != '\n') {
1203                              line++;
1204                              len--;
1205                        }
1206                        emit_line(ecbdata->opt, plain, reset, line, len);
1207                }
1208                return;
1209        }
1210
1211        if (line[0] != '+') {
1212                const char *color =
1213                        diff_get_color(ecbdata->color_diff,
1214                                       line[0] == '-' ? DIFF_FILE_OLD : DIFF_PLAIN);
1215                ecbdata->lno_in_preimage++;
1216                if (line[0] == ' ')
1217                        ecbdata->lno_in_postimage++;
1218                emit_line(ecbdata->opt, color, reset, line, len);
1219        } else {
1220                ecbdata->lno_in_postimage++;
1221                emit_add_line(reset, ecbdata, line + 1, len - 1);
1222        }
1223}
1224
1225static char *pprint_rename(const char *a, const char *b)
1226{
1227        const char *old = a;
1228        const char *new = b;
1229        struct strbuf name = STRBUF_INIT;
1230        int pfx_length, sfx_length;
1231        int len_a = strlen(a);
1232        int len_b = strlen(b);
1233        int a_midlen, b_midlen;
1234        int qlen_a = quote_c_style(a, NULL, NULL, 0);
1235        int qlen_b = quote_c_style(b, NULL, NULL, 0);
1236
1237        if (qlen_a || qlen_b) {
1238                quote_c_style(a, &name, NULL, 0);
1239                strbuf_addstr(&name, " => ");
1240                quote_c_style(b, &name, NULL, 0);
1241                return strbuf_detach(&name, NULL);
1242        }
1243
1244        /* Find common prefix */
1245        pfx_length = 0;
1246        while (*old && *new && *old == *new) {
1247                if (*old == '/')
1248                        pfx_length = old - a + 1;
1249                old++;
1250                new++;
1251        }
1252
1253        /* Find common suffix */
1254        old = a + len_a;
1255        new = b + len_b;
1256        sfx_length = 0;
1257        while (a <= old && b <= new && *old == *new) {
1258                if (*old == '/')
1259                        sfx_length = len_a - (old - a);
1260                old--;
1261                new--;
1262        }
1263
1264        /*
1265         * pfx{mid-a => mid-b}sfx
1266         * {pfx-a => pfx-b}sfx
1267         * pfx{sfx-a => sfx-b}
1268         * name-a => name-b
1269         */
1270        a_midlen = len_a - pfx_length - sfx_length;
1271        b_midlen = len_b - pfx_length - sfx_length;
1272        if (a_midlen < 0)
1273                a_midlen = 0;
1274        if (b_midlen < 0)
1275                b_midlen = 0;
1276
1277        strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1278        if (pfx_length + sfx_length) {
1279                strbuf_add(&name, a, pfx_length);
1280                strbuf_addch(&name, '{');
1281        }
1282        strbuf_add(&name, a + pfx_length, a_midlen);
1283        strbuf_addstr(&name, " => ");
1284        strbuf_add(&name, b + pfx_length, b_midlen);
1285        if (pfx_length + sfx_length) {
1286                strbuf_addch(&name, '}');
1287                strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1288        }
1289        return strbuf_detach(&name, NULL);
1290}
1291
1292struct diffstat_t {
1293        int nr;
1294        int alloc;
1295        struct diffstat_file {
1296                char *from_name;
1297                char *name;
1298                char *print_name;
1299                unsigned is_unmerged:1;
1300                unsigned is_binary:1;
1301                unsigned is_renamed:1;
1302                uintmax_t added, deleted;
1303        } **files;
1304};
1305
1306static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1307                                          const char *name_a,
1308                                          const char *name_b)
1309{
1310        struct diffstat_file *x;
1311        x = xcalloc(sizeof (*x), 1);
1312        if (diffstat->nr == diffstat->alloc) {
1313                diffstat->alloc = alloc_nr(diffstat->alloc);
1314                diffstat->files = xrealloc(diffstat->files,
1315                                diffstat->alloc * sizeof(x));
1316        }
1317        diffstat->files[diffstat->nr++] = x;
1318        if (name_b) {
1319                x->from_name = xstrdup(name_a);
1320                x->name = xstrdup(name_b);
1321                x->is_renamed = 1;
1322        }
1323        else {
1324                x->from_name = NULL;
1325                x->name = xstrdup(name_a);
1326        }
1327        return x;
1328}
1329
1330static void diffstat_consume(void *priv, char *line, unsigned long len)
1331{
1332        struct diffstat_t *diffstat = priv;
1333        struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1334
1335        if (line[0] == '+')
1336                x->added++;
1337        else if (line[0] == '-')
1338                x->deleted++;
1339}
1340
1341const char mime_boundary_leader[] = "------------";
1342
1343static int scale_linear(int it, int width, int max_change)
1344{
1345        if (!it)
1346                return 0;
1347        /*
1348         * make sure that at least one '-' or '+' is printed if
1349         * there is any change to this path. The easiest way is to
1350         * scale linearly as if the alloted width is one column shorter
1351         * than it is, and then add 1 to the result.
1352         */
1353        return 1 + (it * (width - 1) / max_change);
1354}
1355
1356static void show_name(FILE *file,
1357                      const char *prefix, const char *name, int len)
1358{
1359        fprintf(file, " %s%-*s |", prefix, len, name);
1360}
1361
1362static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1363{
1364        if (cnt <= 0)
1365                return;
1366        fprintf(file, "%s", set);
1367        while (cnt--)
1368                putc(ch, file);
1369        fprintf(file, "%s", reset);
1370}
1371
1372static void fill_print_name(struct diffstat_file *file)
1373{
1374        char *pname;
1375
1376        if (file->print_name)
1377                return;
1378
1379        if (!file->is_renamed) {
1380                struct strbuf buf = STRBUF_INIT;
1381                if (quote_c_style(file->name, &buf, NULL, 0)) {
1382                        pname = strbuf_detach(&buf, NULL);
1383                } else {
1384                        pname = file->name;
1385                        strbuf_release(&buf);
1386                }
1387        } else {
1388                pname = pprint_rename(file->from_name, file->name);
1389        }
1390        file->print_name = pname;
1391}
1392
1393int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1394{
1395        struct strbuf sb = STRBUF_INIT;
1396        int ret;
1397
1398        if (!files) {
1399                assert(insertions == 0 && deletions == 0);
1400                return fputs(_(" 0 files changed\n"), fp);
1401        }
1402
1403        strbuf_addf(&sb,
1404                    Q_(" %d file changed", " %d files changed", files),
1405                    files);
1406
1407        /*
1408         * For binary diff, the caller may want to print "x files
1409         * changed" with insertions == 0 && deletions == 0.
1410         *
1411         * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1412         * is probably less confusing (i.e skip over "2 files changed
1413         * but nothing about added/removed lines? Is this a bug in Git?").
1414         */
1415        if (insertions || deletions == 0) {
1416                /*
1417                 * TRANSLATORS: "+" in (+) is a line addition marker;
1418                 * do not translate it.
1419                 */
1420                strbuf_addf(&sb,
1421                            Q_(", %d insertion(+)", ", %d insertions(+)",
1422                               insertions),
1423                            insertions);
1424        }
1425
1426        if (deletions || insertions == 0) {
1427                /*
1428                 * TRANSLATORS: "-" in (-) is a line removal marker;
1429                 * do not translate it.
1430                 */
1431                strbuf_addf(&sb,
1432                            Q_(", %d deletion(-)", ", %d deletions(-)",
1433                               deletions),
1434                            deletions);
1435        }
1436        strbuf_addch(&sb, '\n');
1437        ret = fputs(sb.buf, fp);
1438        strbuf_release(&sb);
1439        return ret;
1440}
1441
1442static void show_stats(struct diffstat_t *data, struct diff_options *options)
1443{
1444        int i, len, add, del, adds = 0, dels = 0;
1445        uintmax_t max_change = 0, max_len = 0;
1446        int total_files = data->nr;
1447        int width, name_width, graph_width, number_width = 4, count;
1448        const char *reset, *add_c, *del_c;
1449        const char *line_prefix = "";
1450        int extra_shown = 0;
1451        struct strbuf *msg = NULL;
1452
1453        if (data->nr == 0)
1454                return;
1455
1456        if (options->output_prefix) {
1457                msg = options->output_prefix(options, options->output_prefix_data);
1458                line_prefix = msg->buf;
1459        }
1460
1461        count = options->stat_count ? options->stat_count : data->nr;
1462
1463        reset = diff_get_color_opt(options, DIFF_RESET);
1464        add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1465        del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1466
1467        /*
1468         * Find the longest filename and max number of changes
1469         */
1470        for (i = 0; (i < count) && (i < data->nr); i++) {
1471                struct diffstat_file *file = data->files[i];
1472                uintmax_t change = file->added + file->deleted;
1473                if (!data->files[i]->is_renamed &&
1474                         (change == 0)) {
1475                        count++; /* not shown == room for one more */
1476                        continue;
1477                }
1478                fill_print_name(file);
1479                len = strlen(file->print_name);
1480                if (max_len < len)
1481                        max_len = len;
1482
1483                if (file->is_binary || file->is_unmerged)
1484                        continue;
1485                if (max_change < change)
1486                        max_change = change;
1487        }
1488        count = i; /* min(count, data->nr) */
1489
1490        /*
1491         * We have width = stat_width or term_columns() columns total.
1492         * We want a maximum of min(max_len, stat_name_width) for the name part.
1493         * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1494         * We also need 1 for " " and 4 + decimal_width(max_change)
1495         * for " | NNNN " and one the empty column at the end, altogether
1496         * 6 + decimal_width(max_change).
1497         *
1498         * If there's not enough space, we will use the smaller of
1499         * stat_name_width (if set) and 5/8*width for the filename,
1500         * and the rest for constant elements + graph part, but no more
1501         * than stat_graph_width for the graph part.
1502         * (5/8 gives 50 for filename and 30 for the constant parts + graph
1503         * for the standard terminal size).
1504         *
1505         * In other words: stat_width limits the maximum width, and
1506         * stat_name_width fixes the maximum width of the filename,
1507         * and is also used to divide available columns if there
1508         * aren't enough.
1509         */
1510
1511        if (options->stat_width == -1)
1512                width = term_columns();
1513        else
1514                width = options->stat_width ? options->stat_width : 80;
1515
1516        if (options->stat_graph_width == -1)
1517                options->stat_graph_width = diff_stat_graph_width;
1518
1519        /*
1520         * Guarantee 3/8*16==6 for the graph part
1521         * and 5/8*16==10 for the filename part
1522         */
1523        if (width < 16 + 6 + number_width)
1524                width = 16 + 6 + number_width;
1525
1526        /*
1527         * First assign sizes that are wanted, ignoring available width.
1528         */
1529        graph_width = (options->stat_graph_width &&
1530                       options->stat_graph_width < max_change) ?
1531                options->stat_graph_width : max_change;
1532        name_width = (options->stat_name_width > 0 &&
1533                      options->stat_name_width < max_len) ?
1534                options->stat_name_width : max_len;
1535
1536        /*
1537         * Adjust adjustable widths not to exceed maximum width
1538         */
1539        if (name_width + number_width + 6 + graph_width > width) {
1540                if (graph_width > width * 3/8 - number_width - 6)
1541                        graph_width = width * 3/8 - number_width - 6;
1542                if (options->stat_graph_width &&
1543                    graph_width > options->stat_graph_width)
1544                        graph_width = options->stat_graph_width;
1545                if (name_width > width - number_width - 6 - graph_width)
1546                        name_width = width - number_width - 6 - graph_width;
1547                else
1548                        graph_width = width - number_width - 6 - name_width;
1549        }
1550
1551        /*
1552         * From here name_width is the width of the name area,
1553         * and graph_width is the width of the graph area.
1554         * max_change is used to scale graph properly.
1555         */
1556        for (i = 0; i < count; i++) {
1557                const char *prefix = "";
1558                char *name = data->files[i]->print_name;
1559                uintmax_t added = data->files[i]->added;
1560                uintmax_t deleted = data->files[i]->deleted;
1561                int name_len;
1562
1563                if (!data->files[i]->is_renamed &&
1564                         (added + deleted == 0)) {
1565                        total_files--;
1566                        continue;
1567                }
1568                /*
1569                 * "scale" the filename
1570                 */
1571                len = name_width;
1572                name_len = strlen(name);
1573                if (name_width < name_len) {
1574                        char *slash;
1575                        prefix = "...";
1576                        len -= 3;
1577                        name += name_len - len;
1578                        slash = strchr(name, '/');
1579                        if (slash)
1580                                name = slash;
1581                }
1582
1583                if (data->files[i]->is_binary) {
1584                        fprintf(options->file, "%s", line_prefix);
1585                        show_name(options->file, prefix, name, len);
1586                        fprintf(options->file, "  Bin ");
1587                        fprintf(options->file, "%s%"PRIuMAX"%s",
1588                                del_c, deleted, reset);
1589                        fprintf(options->file, " -> ");
1590                        fprintf(options->file, "%s%"PRIuMAX"%s",
1591                                add_c, added, reset);
1592                        fprintf(options->file, " bytes");
1593                        fprintf(options->file, "\n");
1594                        continue;
1595                }
1596                else if (data->files[i]->is_unmerged) {
1597                        fprintf(options->file, "%s", line_prefix);
1598                        show_name(options->file, prefix, name, len);
1599                        fprintf(options->file, "  Unmerged\n");
1600                        continue;
1601                }
1602
1603                /*
1604                 * scale the add/delete
1605                 */
1606                add = added;
1607                del = deleted;
1608                adds += add;
1609                dels += del;
1610
1611                if (graph_width <= max_change) {
1612                        int total = add + del;
1613
1614                        total = scale_linear(add + del, graph_width, max_change);
1615                        if (total < 2 && add && del)
1616                                /* width >= 2 due to the sanity check */
1617                                total = 2;
1618                        if (add < del) {
1619                                add = scale_linear(add, graph_width, max_change);
1620                                del = total - add;
1621                        } else {
1622                                del = scale_linear(del, graph_width, max_change);
1623                                add = total - del;
1624                        }
1625                }
1626                fprintf(options->file, "%s", line_prefix);
1627                show_name(options->file, prefix, name, len);
1628                fprintf(options->file, "%5"PRIuMAX"%s", added + deleted,
1629                                added + deleted ? " " : "");
1630                show_graph(options->file, '+', add, add_c, reset);
1631                show_graph(options->file, '-', del, del_c, reset);
1632                fprintf(options->file, "\n");
1633        }
1634        for (i = count; i < data->nr; i++) {
1635                uintmax_t added = data->files[i]->added;
1636                uintmax_t deleted = data->files[i]->deleted;
1637                if (!data->files[i]->is_renamed &&
1638                         (added + deleted == 0)) {
1639                        total_files--;
1640                        continue;
1641                }
1642                adds += added;
1643                dels += deleted;
1644                if (!extra_shown)
1645                        fprintf(options->file, "%s ...\n", line_prefix);
1646                extra_shown = 1;
1647        }
1648        fprintf(options->file, "%s", line_prefix);
1649        print_stat_summary(options->file, total_files, adds, dels);
1650}
1651
1652static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1653{
1654        int i, adds = 0, dels = 0, total_files = data->nr;
1655
1656        if (data->nr == 0)
1657                return;
1658
1659        for (i = 0; i < data->nr; i++) {
1660                if (!data->files[i]->is_binary &&
1661                    !data->files[i]->is_unmerged) {
1662                        int added = data->files[i]->added;
1663                        int deleted= data->files[i]->deleted;
1664                        if (!data->files[i]->is_renamed &&
1665                            (added + deleted == 0)) {
1666                                total_files--;
1667                        } else {
1668                                adds += added;
1669                                dels += deleted;
1670                        }
1671                }
1672        }
1673        if (options->output_prefix) {
1674                struct strbuf *msg = NULL;
1675                msg = options->output_prefix(options,
1676                                options->output_prefix_data);
1677                fprintf(options->file, "%s", msg->buf);
1678        }
1679        print_stat_summary(options->file, total_files, adds, dels);
1680}
1681
1682static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1683{
1684        int i;
1685
1686        if (data->nr == 0)
1687                return;
1688
1689        for (i = 0; i < data->nr; i++) {
1690                struct diffstat_file *file = data->files[i];
1691
1692                if (options->output_prefix) {
1693                        struct strbuf *msg = NULL;
1694                        msg = options->output_prefix(options,
1695                                        options->output_prefix_data);
1696                        fprintf(options->file, "%s", msg->buf);
1697                }
1698
1699                if (file->is_binary)
1700                        fprintf(options->file, "-\t-\t");
1701                else
1702                        fprintf(options->file,
1703                                "%"PRIuMAX"\t%"PRIuMAX"\t",
1704                                file->added, file->deleted);
1705                if (options->line_termination) {
1706                        fill_print_name(file);
1707                        if (!file->is_renamed)
1708                                write_name_quoted(file->name, options->file,
1709                                                  options->line_termination);
1710                        else {
1711                                fputs(file->print_name, options->file);
1712                                putc(options->line_termination, options->file);
1713                        }
1714                } else {
1715                        if (file->is_renamed) {
1716                                putc('\0', options->file);
1717                                write_name_quoted(file->from_name, options->file, '\0');
1718                        }
1719                        write_name_quoted(file->name, options->file, '\0');
1720                }
1721        }
1722}
1723
1724struct dirstat_file {
1725        const char *name;
1726        unsigned long changed;
1727};
1728
1729struct dirstat_dir {
1730        struct dirstat_file *files;
1731        int alloc, nr, permille, cumulative;
1732};
1733
1734static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1735                unsigned long changed, const char *base, int baselen)
1736{
1737        unsigned long this_dir = 0;
1738        unsigned int sources = 0;
1739        const char *line_prefix = "";
1740        struct strbuf *msg = NULL;
1741
1742        if (opt->output_prefix) {
1743                msg = opt->output_prefix(opt, opt->output_prefix_data);
1744                line_prefix = msg->buf;
1745        }
1746
1747        while (dir->nr) {
1748                struct dirstat_file *f = dir->files;
1749                int namelen = strlen(f->name);
1750                unsigned long this;
1751                char *slash;
1752
1753                if (namelen < baselen)
1754                        break;
1755                if (memcmp(f->name, base, baselen))
1756                        break;
1757                slash = strchr(f->name + baselen, '/');
1758                if (slash) {
1759                        int newbaselen = slash + 1 - f->name;
1760                        this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1761                        sources++;
1762                } else {
1763                        this = f->changed;
1764                        dir->files++;
1765                        dir->nr--;
1766                        sources += 2;
1767                }
1768                this_dir += this;
1769        }
1770
1771        /*
1772         * We don't report dirstat's for
1773         *  - the top level
1774         *  - or cases where everything came from a single directory
1775         *    under this directory (sources == 1).
1776         */
1777        if (baselen && sources != 1) {
1778                if (this_dir) {
1779                        int permille = this_dir * 1000 / changed;
1780                        if (permille >= dir->permille) {
1781                                fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1782                                        permille / 10, permille % 10, baselen, base);
1783                                if (!dir->cumulative)
1784                                        return 0;
1785                        }
1786                }
1787        }
1788        return this_dir;
1789}
1790
1791static int dirstat_compare(const void *_a, const void *_b)
1792{
1793        const struct dirstat_file *a = _a;
1794        const struct dirstat_file *b = _b;
1795        return strcmp(a->name, b->name);
1796}
1797
1798static void show_dirstat(struct diff_options *options)
1799{
1800        int i;
1801        unsigned long changed;
1802        struct dirstat_dir dir;
1803        struct diff_queue_struct *q = &diff_queued_diff;
1804
1805        dir.files = NULL;
1806        dir.alloc = 0;
1807        dir.nr = 0;
1808        dir.permille = options->dirstat_permille;
1809        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1810
1811        changed = 0;
1812        for (i = 0; i < q->nr; i++) {
1813                struct diff_filepair *p = q->queue[i];
1814                const char *name;
1815                unsigned long copied, added, damage;
1816                int content_changed;
1817
1818                name = p->two->path ? p->two->path : p->one->path;
1819
1820                if (p->one->sha1_valid && p->two->sha1_valid)
1821                        content_changed = hashcmp(p->one->sha1, p->two->sha1);
1822                else
1823                        content_changed = 1;
1824
1825                if (!content_changed) {
1826                        /*
1827                         * The SHA1 has not changed, so pre-/post-content is
1828                         * identical. We can therefore skip looking at the
1829                         * file contents altogether.
1830                         */
1831                        damage = 0;
1832                        goto found_damage;
1833                }
1834
1835                if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1836                        /*
1837                         * In --dirstat-by-file mode, we don't really need to
1838                         * look at the actual file contents at all.
1839                         * The fact that the SHA1 changed is enough for us to
1840                         * add this file to the list of results
1841                         * (with each file contributing equal damage).
1842                         */
1843                        damage = 1;
1844                        goto found_damage;
1845                }
1846
1847                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1848                        diff_populate_filespec(p->one, 0);
1849                        diff_populate_filespec(p->two, 0);
1850                        diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1851                                               &copied, &added);
1852                        diff_free_filespec_data(p->one);
1853                        diff_free_filespec_data(p->two);
1854                } else if (DIFF_FILE_VALID(p->one)) {
1855                        diff_populate_filespec(p->one, 1);
1856                        copied = added = 0;
1857                        diff_free_filespec_data(p->one);
1858                } else if (DIFF_FILE_VALID(p->two)) {
1859                        diff_populate_filespec(p->two, 1);
1860                        copied = 0;
1861                        added = p->two->size;
1862                        diff_free_filespec_data(p->two);
1863                } else
1864                        continue;
1865
1866                /*
1867                 * Original minus copied is the removed material,
1868                 * added is the new material.  They are both damages
1869                 * made to the preimage.
1870                 * If the resulting damage is zero, we know that
1871                 * diffcore_count_changes() considers the two entries to
1872                 * be identical, but since content_changed is true, we
1873                 * know that there must have been _some_ kind of change,
1874                 * so we force all entries to have damage > 0.
1875                 */
1876                damage = (p->one->size - copied) + added;
1877                if (!damage)
1878                        damage = 1;
1879
1880found_damage:
1881                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1882                dir.files[dir.nr].name = name;
1883                dir.files[dir.nr].changed = damage;
1884                changed += damage;
1885                dir.nr++;
1886        }
1887
1888        /* This can happen even with many files, if everything was renames */
1889        if (!changed)
1890                return;
1891
1892        /* Show all directories with more than x% of the changes */
1893        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1894        gather_dirstat(options, &dir, changed, "", 0);
1895}
1896
1897static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
1898{
1899        int i;
1900        unsigned long changed;
1901        struct dirstat_dir dir;
1902
1903        if (data->nr == 0)
1904                return;
1905
1906        dir.files = NULL;
1907        dir.alloc = 0;
1908        dir.nr = 0;
1909        dir.permille = options->dirstat_permille;
1910        dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1911
1912        changed = 0;
1913        for (i = 0; i < data->nr; i++) {
1914                struct diffstat_file *file = data->files[i];
1915                unsigned long damage = file->added + file->deleted;
1916                if (file->is_binary)
1917                        /*
1918                         * binary files counts bytes, not lines. Must find some
1919                         * way to normalize binary bytes vs. textual lines.
1920                         * The following heuristic assumes that there are 64
1921                         * bytes per "line".
1922                         * This is stupid and ugly, but very cheap...
1923                         */
1924                        damage = (damage + 63) / 64;
1925                ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1926                dir.files[dir.nr].name = file->name;
1927                dir.files[dir.nr].changed = damage;
1928                changed += damage;
1929                dir.nr++;
1930        }
1931
1932        /* This can happen even with many files, if everything was renames */
1933        if (!changed)
1934                return;
1935
1936        /* Show all directories with more than x% of the changes */
1937        qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1938        gather_dirstat(options, &dir, changed, "", 0);
1939}
1940
1941static void free_diffstat_info(struct diffstat_t *diffstat)
1942{
1943        int i;
1944        for (i = 0; i < diffstat->nr; i++) {
1945                struct diffstat_file *f = diffstat->files[i];
1946                if (f->name != f->print_name)
1947                        free(f->print_name);
1948                free(f->name);
1949                free(f->from_name);
1950                free(f);
1951        }
1952        free(diffstat->files);
1953}
1954
1955struct checkdiff_t {
1956        const char *filename;
1957        int lineno;
1958        int conflict_marker_size;
1959        struct diff_options *o;
1960        unsigned ws_rule;
1961        unsigned status;
1962};
1963
1964static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
1965{
1966        char firstchar;
1967        int cnt;
1968
1969        if (len < marker_size + 1)
1970                return 0;
1971        firstchar = line[0];
1972        switch (firstchar) {
1973        case '=': case '>': case '<': case '|':
1974                break;
1975        default:
1976                return 0;
1977        }
1978        for (cnt = 1; cnt < marker_size; cnt++)
1979                if (line[cnt] != firstchar)
1980                        return 0;
1981        /* line[1] thru line[marker_size-1] are same as firstchar */
1982        if (len < marker_size + 1 || !isspace(line[marker_size]))
1983                return 0;
1984        return 1;
1985}
1986
1987static void checkdiff_consume(void *priv, char *line, unsigned long len)
1988{
1989        struct checkdiff_t *data = priv;
1990        int marker_size = data->conflict_marker_size;
1991        const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
1992        const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
1993        const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
1994        char *err;
1995        char *line_prefix = "";
1996        struct strbuf *msgbuf;
1997
1998        assert(data->o);
1999        if (data->o->output_prefix) {
2000                msgbuf = data->o->output_prefix(data->o,
2001                        data->o->output_prefix_data);
2002                line_prefix = msgbuf->buf;
2003        }
2004
2005        if (line[0] == '+') {
2006                unsigned bad;
2007                data->lineno++;
2008                if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2009                        data->status |= 1;
2010                        fprintf(data->o->file,
2011                                "%s%s:%d: leftover conflict marker\n",
2012                                line_prefix, data->filename, data->lineno);
2013                }
2014                bad = ws_check(line + 1, len - 1, data->ws_rule);
2015                if (!bad)
2016                        return;
2017                data->status |= bad;
2018                err = whitespace_error_string(bad);
2019                fprintf(data->o->file, "%s%s:%d: %s.\n",
2020                        line_prefix, data->filename, data->lineno, err);
2021                free(err);
2022                emit_line(data->o, set, reset, line, 1);
2023                ws_check_emit(line + 1, len - 1, data->ws_rule,
2024                              data->o->file, set, reset, ws);
2025        } else if (line[0] == ' ') {
2026                data->lineno++;
2027        } else if (line[0] == '@') {
2028                char *plus = strchr(line, '+');
2029                if (plus)
2030                        data->lineno = strtol(plus, NULL, 10) - 1;
2031                else
2032                        die("invalid diff");
2033        }
2034}
2035
2036static unsigned char *deflate_it(char *data,
2037                                 unsigned long size,
2038                                 unsigned long *result_size)
2039{
2040        int bound;
2041        unsigned char *deflated;
2042        git_zstream stream;
2043
2044        memset(&stream, 0, sizeof(stream));
2045        git_deflate_init(&stream, zlib_compression_level);
2046        bound = git_deflate_bound(&stream, size);
2047        deflated = xmalloc(bound);
2048        stream.next_out = deflated;
2049        stream.avail_out = bound;
2050
2051        stream.next_in = (unsigned char *)data;
2052        stream.avail_in = size;
2053        while (git_deflate(&stream, Z_FINISH) == Z_OK)
2054                ; /* nothing */
2055        git_deflate_end(&stream);
2056        *result_size = stream.total_out;
2057        return deflated;
2058}
2059
2060static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two, char *prefix)
2061{
2062        void *cp;
2063        void *delta;
2064        void *deflated;
2065        void *data;
2066        unsigned long orig_size;
2067        unsigned long delta_size;
2068        unsigned long deflate_size;
2069        unsigned long data_size;
2070
2071        /* We could do deflated delta, or we could do just deflated two,
2072         * whichever is smaller.
2073         */
2074        delta = NULL;
2075        deflated = deflate_it(two->ptr, two->size, &deflate_size);
2076        if (one->size && two->size) {
2077                delta = diff_delta(one->ptr, one->size,
2078                                   two->ptr, two->size,
2079                                   &delta_size, deflate_size);
2080                if (delta) {
2081                        void *to_free = delta;
2082                        orig_size = delta_size;
2083                        delta = deflate_it(delta, delta_size, &delta_size);
2084                        free(to_free);
2085                }
2086        }
2087
2088        if (delta && delta_size < deflate_size) {
2089                fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2090                free(deflated);
2091                data = delta;
2092                data_size = delta_size;
2093        }
2094        else {
2095                fprintf(file, "%sliteral %lu\n", prefix, two->size);
2096                free(delta);
2097                data = deflated;
2098                data_size = deflate_size;
2099        }
2100
2101        /* emit data encoded in base85 */
2102        cp = data;
2103        while (data_size) {
2104                int bytes = (52 < data_size) ? 52 : data_size;
2105                char line[70];
2106                data_size -= bytes;
2107                if (bytes <= 26)
2108                        line[0] = bytes + 'A' - 1;
2109                else
2110                        line[0] = bytes - 26 + 'a' - 1;
2111                encode_85(line + 1, cp, bytes);
2112                cp = (char *) cp + bytes;
2113                fprintf(file, "%s", prefix);
2114                fputs(line, file);
2115                fputc('\n', file);
2116        }
2117        fprintf(file, "%s\n", prefix);
2118        free(data);
2119}
2120
2121static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two, char *prefix)
2122{
2123        fprintf(file, "%sGIT binary patch\n", prefix);
2124        emit_binary_diff_body(file, one, two, prefix);
2125        emit_binary_diff_body(file, two, one, prefix);
2126}
2127
2128int diff_filespec_is_binary(struct diff_filespec *one)
2129{
2130        if (one->is_binary == -1) {
2131                diff_filespec_load_driver(one);
2132                if (one->driver->binary != -1)
2133                        one->is_binary = one->driver->binary;
2134                else {
2135                        if (!one->data && DIFF_FILE_VALID(one))
2136                                diff_populate_filespec(one, 0);
2137                        if (one->data)
2138                                one->is_binary = buffer_is_binary(one->data,
2139                                                one->size);
2140                        if (one->is_binary == -1)
2141                                one->is_binary = 0;
2142                }
2143        }
2144        return one->is_binary;
2145}
2146
2147static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2148{
2149        diff_filespec_load_driver(one);
2150        return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2151}
2152
2153void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2154{
2155        if (!options->a_prefix)
2156                options->a_prefix = a;
2157        if (!options->b_prefix)
2158                options->b_prefix = b;
2159}
2160
2161struct userdiff_driver *get_textconv(struct diff_filespec *one)
2162{
2163        if (!DIFF_FILE_VALID(one))
2164                return NULL;
2165
2166        diff_filespec_load_driver(one);
2167        return userdiff_get_textconv(one->driver);
2168}
2169
2170static void builtin_diff(const char *name_a,
2171                         const char *name_b,
2172                         struct diff_filespec *one,
2173                         struct diff_filespec *two,
2174                         const char *xfrm_msg,
2175                         int must_show_header,
2176                         struct diff_options *o,
2177                         int complete_rewrite)
2178{
2179        mmfile_t mf1, mf2;
2180        const char *lbl[2];
2181        char *a_one, *b_two;
2182        const char *set = diff_get_color_opt(o, DIFF_METAINFO);
2183        const char *reset = diff_get_color_opt(o, DIFF_RESET);
2184        const char *a_prefix, *b_prefix;
2185        struct userdiff_driver *textconv_one = NULL;
2186        struct userdiff_driver *textconv_two = NULL;
2187        struct strbuf header = STRBUF_INIT;
2188        struct strbuf *msgbuf;
2189        char *line_prefix = "";
2190
2191        if (o->output_prefix) {
2192                msgbuf = o->output_prefix(o, o->output_prefix_data);
2193                line_prefix = msgbuf->buf;
2194        }
2195
2196        if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2197                        (!one->mode || S_ISGITLINK(one->mode)) &&
2198                        (!two->mode || S_ISGITLINK(two->mode))) {
2199                const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2200                const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2201                show_submodule_summary(o->file, one ? one->path : two->path,
2202                                one->sha1, two->sha1, two->dirty_submodule,
2203                                del, add, reset);
2204                return;
2205        }
2206
2207        if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2208                textconv_one = get_textconv(one);
2209                textconv_two = get_textconv(two);
2210        }
2211
2212        diff_set_mnemonic_prefix(o, "a/", "b/");
2213        if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2214                a_prefix = o->b_prefix;
2215                b_prefix = o->a_prefix;
2216        } else {
2217                a_prefix = o->a_prefix;
2218                b_prefix = o->b_prefix;
2219        }
2220
2221        /* Never use a non-valid filename anywhere if at all possible */
2222        name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2223        name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2224
2225        a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2226        b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2227        lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2228        lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2229        strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, set, a_one, b_two, reset);
2230        if (lbl[0][0] == '/') {
2231                /* /dev/null */
2232                strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, set, two->mode, reset);
2233                if (xfrm_msg)
2234                        strbuf_addstr(&header, xfrm_msg);
2235                must_show_header = 1;
2236        }
2237        else if (lbl[1][0] == '/') {
2238                strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, set, one->mode, reset);
2239                if (xfrm_msg)
2240                        strbuf_addstr(&header, xfrm_msg);
2241                must_show_header = 1;
2242        }
2243        else {
2244                if (one->mode != two->mode) {
2245                        strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, set, one->mode, reset);
2246                        strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, set, two->mode, reset);
2247                        must_show_header = 1;
2248                }
2249                if (xfrm_msg)
2250                        strbuf_addstr(&header, xfrm_msg);
2251
2252                /*
2253                 * we do not run diff between different kind
2254                 * of objects.
2255                 */
2256                if ((one->mode ^ two->mode) & S_IFMT)
2257                        goto free_ab_and_return;
2258                if (complete_rewrite &&
2259                    (textconv_one || !diff_filespec_is_binary(one)) &&
2260                    (textconv_two || !diff_filespec_is_binary(two))) {
2261                        fprintf(o->file, "%s", header.buf);
2262                        strbuf_reset(&header);
2263                        emit_rewrite_diff(name_a, name_b, one, two,
2264                                                textconv_one, textconv_two, o);
2265                        o->found_changes = 1;
2266                        goto free_ab_and_return;
2267                }
2268        }
2269
2270        if (o->irreversible_delete && lbl[1][0] == '/') {
2271                fprintf(o->file, "%s", header.buf);
2272                strbuf_reset(&header);
2273                goto free_ab_and_return;
2274        } else if (!DIFF_OPT_TST(o, TEXT) &&
2275            ( (!textconv_one && diff_filespec_is_binary(one)) ||
2276              (!textconv_two && diff_filespec_is_binary(two)) )) {
2277                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2278                        die("unable to read files to diff");
2279                /* Quite common confusing case */
2280                if (mf1.size == mf2.size &&
2281                    !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2282                        if (must_show_header)
2283                                fprintf(o->file, "%s", header.buf);
2284                        goto free_ab_and_return;
2285                }
2286                fprintf(o->file, "%s", header.buf);
2287                strbuf_reset(&header);
2288                if (DIFF_OPT_TST(o, BINARY))
2289                        emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2290                else
2291                        fprintf(o->file, "%sBinary files %s and %s differ\n",
2292                                line_prefix, lbl[0], lbl[1]);
2293                o->found_changes = 1;
2294        } else {
2295                /* Crazy xdl interfaces.. */
2296                const char *diffopts = getenv("GIT_DIFF_OPTS");
2297                xpparam_t xpp;
2298                xdemitconf_t xecfg;
2299                struct emit_callback ecbdata;
2300                const struct userdiff_funcname *pe;
2301
2302                if (must_show_header) {
2303                        fprintf(o->file, "%s", header.buf);
2304                        strbuf_reset(&header);
2305                }
2306
2307                mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2308                mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2309
2310                pe = diff_funcname_pattern(one);
2311                if (!pe)
2312                        pe = diff_funcname_pattern(two);
2313
2314                memset(&xpp, 0, sizeof(xpp));
2315                memset(&xecfg, 0, sizeof(xecfg));
2316                memset(&ecbdata, 0, sizeof(ecbdata));
2317                ecbdata.label_path = lbl;
2318                ecbdata.color_diff = want_color(o->use_color);
2319                ecbdata.found_changesp = &o->found_changes;
2320                ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
2321                if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2322                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2323                ecbdata.opt = o;
2324                ecbdata.header = header.len ? &header : NULL;
2325                xpp.flags = o->xdl_opts;
2326                xecfg.ctxlen = o->context;
2327                xecfg.interhunkctxlen = o->interhunkcontext;
2328                xecfg.flags = XDL_EMIT_FUNCNAMES;
2329                if (DIFF_OPT_TST(o, FUNCCONTEXT))
2330                        xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2331                if (pe)
2332                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2333                if (!diffopts)
2334                        ;
2335                else if (!prefixcmp(diffopts, "--unified="))
2336                        xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
2337                else if (!prefixcmp(diffopts, "-u"))
2338                        xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
2339                if (o->word_diff)
2340                        init_diff_words_data(&ecbdata, o, one, two);
2341                xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2342                              &xpp, &xecfg);
2343                if (o->word_diff)
2344                        free_diff_words_data(&ecbdata);
2345                if (textconv_one)
2346                        free(mf1.ptr);
2347                if (textconv_two)
2348                        free(mf2.ptr);
2349                xdiff_clear_find_func(&xecfg);
2350        }
2351
2352 free_ab_and_return:
2353        strbuf_release(&header);
2354        diff_free_filespec_data(one);
2355        diff_free_filespec_data(two);
2356        free(a_one);
2357        free(b_two);
2358        return;
2359}
2360
2361static void builtin_diffstat(const char *name_a, const char *name_b,
2362                             struct diff_filespec *one,
2363                             struct diff_filespec *two,
2364                             struct diffstat_t *diffstat,
2365                             struct diff_options *o,
2366                             int complete_rewrite)
2367{
2368        mmfile_t mf1, mf2;
2369        struct diffstat_file *data;
2370
2371        data = diffstat_add(diffstat, name_a, name_b);
2372
2373        if (!one || !two) {
2374                data->is_unmerged = 1;
2375                return;
2376        }
2377
2378        if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2379                data->is_binary = 1;
2380                data->added = diff_filespec_size(two);
2381                data->deleted = diff_filespec_size(one);
2382        }
2383
2384        else if (complete_rewrite) {
2385                diff_populate_filespec(one, 0);
2386                diff_populate_filespec(two, 0);
2387                data->deleted = count_lines(one->data, one->size);
2388                data->added = count_lines(two->data, two->size);
2389        }
2390
2391        else {
2392                /* Crazy xdl interfaces.. */
2393                xpparam_t xpp;
2394                xdemitconf_t xecfg;
2395
2396                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2397                        die("unable to read files to diff");
2398
2399                memset(&xpp, 0, sizeof(xpp));
2400                memset(&xecfg, 0, sizeof(xecfg));
2401                xpp.flags = o->xdl_opts;
2402                xecfg.ctxlen = o->context;
2403                xecfg.interhunkctxlen = o->interhunkcontext;
2404                xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2405                              &xpp, &xecfg);
2406        }
2407
2408        diff_free_filespec_data(one);
2409        diff_free_filespec_data(two);
2410}
2411
2412static void builtin_checkdiff(const char *name_a, const char *name_b,
2413                              const char *attr_path,
2414                              struct diff_filespec *one,
2415                              struct diff_filespec *two,
2416                              struct diff_options *o)
2417{
2418        mmfile_t mf1, mf2;
2419        struct checkdiff_t data;
2420
2421        if (!two)
2422                return;
2423
2424        memset(&data, 0, sizeof(data));
2425        data.filename = name_b ? name_b : name_a;
2426        data.lineno = 0;
2427        data.o = o;
2428        data.ws_rule = whitespace_rule(attr_path);
2429        data.conflict_marker_size = ll_merge_marker_size(attr_path);
2430
2431        if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2432                die("unable to read files to diff");
2433
2434        /*
2435         * All the other codepaths check both sides, but not checking
2436         * the "old" side here is deliberate.  We are checking the newly
2437         * introduced changes, and as long as the "new" side is text, we
2438         * can and should check what it introduces.
2439         */
2440        if (diff_filespec_is_binary(two))
2441                goto free_and_return;
2442        else {
2443                /* Crazy xdl interfaces.. */
2444                xpparam_t xpp;
2445                xdemitconf_t xecfg;
2446
2447                memset(&xpp, 0, sizeof(xpp));
2448                memset(&xecfg, 0, sizeof(xecfg));
2449                xecfg.ctxlen = 1; /* at least one context line */
2450                xpp.flags = 0;
2451                xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2452                              &xpp, &xecfg);
2453
2454                if (data.ws_rule & WS_BLANK_AT_EOF) {
2455                        struct emit_callback ecbdata;
2456                        int blank_at_eof;
2457
2458                        ecbdata.ws_rule = data.ws_rule;
2459                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
2460                        blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2461
2462                        if (blank_at_eof) {
2463                                static char *err;
2464                                if (!err)
2465                                        err = whitespace_error_string(WS_BLANK_AT_EOF);
2466                                fprintf(o->file, "%s:%d: %s.\n",
2467                                        data.filename, blank_at_eof, err);
2468                                data.status = 1; /* report errors */
2469                        }
2470                }
2471        }
2472 free_and_return:
2473        diff_free_filespec_data(one);
2474        diff_free_filespec_data(two);
2475        if (data.status)
2476                DIFF_OPT_SET(o, CHECK_FAILED);
2477}
2478
2479struct diff_filespec *alloc_filespec(const char *path)
2480{
2481        int namelen = strlen(path);
2482        struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
2483
2484        memset(spec, 0, sizeof(*spec));
2485        spec->path = (char *)(spec + 1);
2486        memcpy(spec->path, path, namelen+1);
2487        spec->count = 1;
2488        spec->is_binary = -1;
2489        return spec;
2490}
2491
2492void free_filespec(struct diff_filespec *spec)
2493{
2494        if (!--spec->count) {
2495                diff_free_filespec_data(spec);
2496                free(spec);
2497        }
2498}
2499
2500void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2501                   unsigned short mode)
2502{
2503        if (mode) {
2504                spec->mode = canon_mode(mode);
2505                hashcpy(spec->sha1, sha1);
2506                spec->sha1_valid = !is_null_sha1(sha1);
2507        }
2508}
2509
2510/*
2511 * Given a name and sha1 pair, if the index tells us the file in
2512 * the work tree has that object contents, return true, so that
2513 * prepare_temp_file() does not have to inflate and extract.
2514 */
2515static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2516{
2517        struct cache_entry *ce;
2518        struct stat st;
2519        int pos, len;
2520
2521        /*
2522         * We do not read the cache ourselves here, because the
2523         * benchmark with my previous version that always reads cache
2524         * shows that it makes things worse for diff-tree comparing
2525         * two linux-2.6 kernel trees in an already checked out work
2526         * tree.  This is because most diff-tree comparisons deal with
2527         * only a small number of files, while reading the cache is
2528         * expensive for a large project, and its cost outweighs the
2529         * savings we get by not inflating the object to a temporary
2530         * file.  Practically, this code only helps when we are used
2531         * by diff-cache --cached, which does read the cache before
2532         * calling us.
2533         */
2534        if (!active_cache)
2535                return 0;
2536
2537        /* We want to avoid the working directory if our caller
2538         * doesn't need the data in a normal file, this system
2539         * is rather slow with its stat/open/mmap/close syscalls,
2540         * and the object is contained in a pack file.  The pack
2541         * is probably already open and will be faster to obtain
2542         * the data through than the working directory.  Loose
2543         * objects however would tend to be slower as they need
2544         * to be individually opened and inflated.
2545         */
2546        if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2547                return 0;
2548
2549        len = strlen(name);
2550        pos = cache_name_pos(name, len);
2551        if (pos < 0)
2552                return 0;
2553        ce = active_cache[pos];
2554
2555        /*
2556         * This is not the sha1 we are looking for, or
2557         * unreusable because it is not a regular file.
2558         */
2559        if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2560                return 0;
2561
2562        /*
2563         * If ce is marked as "assume unchanged", there is no
2564         * guarantee that work tree matches what we are looking for.
2565         */
2566        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2567                return 0;
2568
2569        /*
2570         * If ce matches the file in the work tree, we can reuse it.
2571         */
2572        if (ce_uptodate(ce) ||
2573            (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2574                return 1;
2575
2576        return 0;
2577}
2578
2579static int populate_from_stdin(struct diff_filespec *s)
2580{
2581        struct strbuf buf = STRBUF_INIT;
2582        size_t size = 0;
2583
2584        if (strbuf_read(&buf, 0, 0) < 0)
2585                return error("error while reading from stdin %s",
2586                                     strerror(errno));
2587
2588        s->should_munmap = 0;
2589        s->data = strbuf_detach(&buf, &size);
2590        s->size = size;
2591        s->should_free = 1;
2592        return 0;
2593}
2594
2595static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2596{
2597        int len;
2598        char *data = xmalloc(100), *dirty = "";
2599
2600        /* Are we looking at the work tree? */
2601        if (s->dirty_submodule)
2602                dirty = "-dirty";
2603
2604        len = snprintf(data, 100,
2605                       "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2606        s->data = data;
2607        s->size = len;
2608        s->should_free = 1;
2609        if (size_only) {
2610                s->data = NULL;
2611                free(data);
2612        }
2613        return 0;
2614}
2615
2616/*
2617 * While doing rename detection and pickaxe operation, we may need to
2618 * grab the data for the blob (or file) for our own in-core comparison.
2619 * diff_filespec has data and size fields for this purpose.
2620 */
2621int diff_populate_filespec(struct diff_filespec *s, int size_only)
2622{
2623        int err = 0;
2624        if (!DIFF_FILE_VALID(s))
2625                die("internal error: asking to populate invalid file.");
2626        if (S_ISDIR(s->mode))
2627                return -1;
2628
2629        if (s->data)
2630                return 0;
2631
2632        if (size_only && 0 < s->size)
2633                return 0;
2634
2635        if (S_ISGITLINK(s->mode))
2636                return diff_populate_gitlink(s, size_only);
2637
2638        if (!s->sha1_valid ||
2639            reuse_worktree_file(s->path, s->sha1, 0)) {
2640                struct strbuf buf = STRBUF_INIT;
2641                struct stat st;
2642                int fd;
2643
2644                if (!strcmp(s->path, "-"))
2645                        return populate_from_stdin(s);
2646
2647                if (lstat(s->path, &st) < 0) {
2648                        if (errno == ENOENT) {
2649                        err_empty:
2650                                err = -1;
2651                        empty:
2652                                s->data = (char *)"";
2653                                s->size = 0;
2654                                return err;
2655                        }
2656                }
2657                s->size = xsize_t(st.st_size);
2658                if (!s->size)
2659                        goto empty;
2660                if (S_ISLNK(st.st_mode)) {
2661                        struct strbuf sb = STRBUF_INIT;
2662
2663                        if (strbuf_readlink(&sb, s->path, s->size))
2664                                goto err_empty;
2665                        s->size = sb.len;
2666                        s->data = strbuf_detach(&sb, NULL);
2667                        s->should_free = 1;
2668                        return 0;
2669                }
2670                if (size_only)
2671                        return 0;
2672                fd = open(s->path, O_RDONLY);
2673                if (fd < 0)
2674                        goto err_empty;
2675                s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2676                close(fd);
2677                s->should_munmap = 1;
2678
2679                /*
2680                 * Convert from working tree format to canonical git format
2681                 */
2682                if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
2683                        size_t size = 0;
2684                        munmap(s->data, s->size);
2685                        s->should_munmap = 0;
2686                        s->data = strbuf_detach(&buf, &size);
2687                        s->size = size;
2688                        s->should_free = 1;
2689                }
2690        }
2691        else {
2692                enum object_type type;
2693                if (size_only) {
2694                        type = sha1_object_info(s->sha1, &s->size);
2695                        if (type < 0)
2696                                die("unable to read %s", sha1_to_hex(s->sha1));
2697                } else {
2698                        s->data = read_sha1_file(s->sha1, &type, &s->size);
2699                        if (!s->data)
2700                                die("unable to read %s", sha1_to_hex(s->sha1));
2701                        s->should_free = 1;
2702                }
2703        }
2704        return 0;
2705}
2706
2707void diff_free_filespec_blob(struct diff_filespec *s)
2708{
2709        if (s->should_free)
2710                free(s->data);
2711        else if (s->should_munmap)
2712                munmap(s->data, s->size);
2713
2714        if (s->should_free || s->should_munmap) {
2715                s->should_free = s->should_munmap = 0;
2716                s->data = NULL;
2717        }
2718}
2719
2720void diff_free_filespec_data(struct diff_filespec *s)
2721{
2722        diff_free_filespec_blob(s);
2723        free(s->cnt_data);
2724        s->cnt_data = NULL;
2725}
2726
2727static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2728                           void *blob,
2729                           unsigned long size,
2730                           const unsigned char *sha1,
2731                           int mode)
2732{
2733        int fd;
2734        struct strbuf buf = STRBUF_INIT;
2735        struct strbuf template = STRBUF_INIT;
2736        char *path_dup = xstrdup(path);
2737        const char *base = basename(path_dup);
2738
2739        /* Generate "XXXXXX_basename.ext" */
2740        strbuf_addstr(&template, "XXXXXX_");
2741        strbuf_addstr(&template, base);
2742
2743        fd = git_mkstemps(temp->tmp_path, PATH_MAX, template.buf,
2744                        strlen(base) + 1);
2745        if (fd < 0)
2746                die_errno("unable to create temp-file");
2747        if (convert_to_working_tree(path,
2748                        (const char *)blob, (size_t)size, &buf)) {
2749                blob = buf.buf;
2750                size = buf.len;
2751        }
2752        if (write_in_full(fd, blob, size) != size)
2753                die_errno("unable to write temp-file");
2754        close(fd);
2755        temp->name = temp->tmp_path;
2756        strcpy(temp->hex, sha1_to_hex(sha1));
2757        temp->hex[40] = 0;
2758        sprintf(temp->mode, "%06o", mode);
2759        strbuf_release(&buf);
2760        strbuf_release(&template);
2761        free(path_dup);
2762}
2763
2764static struct diff_tempfile *prepare_temp_file(const char *name,
2765                struct diff_filespec *one)
2766{
2767        struct diff_tempfile *temp = claim_diff_tempfile();
2768
2769        if (!DIFF_FILE_VALID(one)) {
2770        not_a_valid_file:
2771                /* A '-' entry produces this for file-2, and
2772                 * a '+' entry produces this for file-1.
2773                 */
2774                temp->name = "/dev/null";
2775                strcpy(temp->hex, ".");
2776                strcpy(temp->mode, ".");
2777                return temp;
2778        }
2779
2780        if (!remove_tempfile_installed) {
2781                atexit(remove_tempfile);
2782                sigchain_push_common(remove_tempfile_on_signal);
2783                remove_tempfile_installed = 1;
2784        }
2785
2786        if (!one->sha1_valid ||
2787            reuse_worktree_file(name, one->sha1, 1)) {
2788                struct stat st;
2789                if (lstat(name, &st) < 0) {
2790                        if (errno == ENOENT)
2791                                goto not_a_valid_file;
2792                        die_errno("stat(%s)", name);
2793                }
2794                if (S_ISLNK(st.st_mode)) {
2795                        struct strbuf sb = STRBUF_INIT;
2796                        if (strbuf_readlink(&sb, name, st.st_size) < 0)
2797                                die_errno("readlink(%s)", name);
2798                        prep_temp_blob(name, temp, sb.buf, sb.len,
2799                                       (one->sha1_valid ?
2800                                        one->sha1 : null_sha1),
2801                                       (one->sha1_valid ?
2802                                        one->mode : S_IFLNK));
2803                        strbuf_release(&sb);
2804                }
2805                else {
2806                        /* we can borrow from the file in the work tree */
2807                        temp->name = name;
2808                        if (!one->sha1_valid)
2809                                strcpy(temp->hex, sha1_to_hex(null_sha1));
2810                        else
2811                                strcpy(temp->hex, sha1_to_hex(one->sha1));
2812                        /* Even though we may sometimes borrow the
2813                         * contents from the work tree, we always want
2814                         * one->mode.  mode is trustworthy even when
2815                         * !(one->sha1_valid), as long as
2816                         * DIFF_FILE_VALID(one).
2817                         */
2818                        sprintf(temp->mode, "%06o", one->mode);
2819                }
2820                return temp;
2821        }
2822        else {
2823                if (diff_populate_filespec(one, 0))
2824                        die("cannot read data blob for %s", one->path);
2825                prep_temp_blob(name, temp, one->data, one->size,
2826                               one->sha1, one->mode);
2827        }
2828        return temp;
2829}
2830
2831/* An external diff command takes:
2832 *
2833 * diff-cmd name infile1 infile1-sha1 infile1-mode \
2834 *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2835 *
2836 */
2837static void run_external_diff(const char *pgm,
2838                              const char *name,
2839                              const char *other,
2840                              struct diff_filespec *one,
2841                              struct diff_filespec *two,
2842                              const char *xfrm_msg,
2843                              int complete_rewrite)
2844{
2845        const char *spawn_arg[10];
2846        int retval;
2847        const char **arg = &spawn_arg[0];
2848
2849        if (one && two) {
2850                struct diff_tempfile *temp_one, *temp_two;
2851                const char *othername = (other ? other : name);
2852                temp_one = prepare_temp_file(name, one);
2853                temp_two = prepare_temp_file(othername, two);
2854                *arg++ = pgm;
2855                *arg++ = name;
2856                *arg++ = temp_one->name;
2857                *arg++ = temp_one->hex;
2858                *arg++ = temp_one->mode;
2859                *arg++ = temp_two->name;
2860                *arg++ = temp_two->hex;
2861                *arg++ = temp_two->mode;
2862                if (other) {
2863                        *arg++ = other;
2864                        *arg++ = xfrm_msg;
2865                }
2866        } else {
2867                *arg++ = pgm;
2868                *arg++ = name;
2869        }
2870        *arg = NULL;
2871        fflush(NULL);
2872        retval = run_command_v_opt(spawn_arg, RUN_USING_SHELL);
2873        remove_tempfile();
2874        if (retval) {
2875                fprintf(stderr, "external diff died, stopping at %s.\n", name);
2876                exit(1);
2877        }
2878}
2879
2880static int similarity_index(struct diff_filepair *p)
2881{
2882        return p->score * 100 / MAX_SCORE;
2883}
2884
2885static void fill_metainfo(struct strbuf *msg,
2886                          const char *name,
2887                          const char *other,
2888                          struct diff_filespec *one,
2889                          struct diff_filespec *two,
2890                          struct diff_options *o,
2891                          struct diff_filepair *p,
2892                          int *must_show_header,
2893                          int use_color)
2894{
2895        const char *set = diff_get_color(use_color, DIFF_METAINFO);
2896        const char *reset = diff_get_color(use_color, DIFF_RESET);
2897        struct strbuf *msgbuf;
2898        char *line_prefix = "";
2899
2900        *must_show_header = 1;
2901        if (o->output_prefix) {
2902                msgbuf = o->output_prefix(o, o->output_prefix_data);
2903                line_prefix = msgbuf->buf;
2904        }
2905        strbuf_init(msg, PATH_MAX * 2 + 300);
2906        switch (p->status) {
2907        case DIFF_STATUS_COPIED:
2908                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2909                            line_prefix, set, similarity_index(p));
2910                strbuf_addf(msg, "%s\n%s%scopy from ",
2911                            reset,  line_prefix, set);
2912                quote_c_style(name, msg, NULL, 0);
2913                strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
2914                quote_c_style(other, msg, NULL, 0);
2915                strbuf_addf(msg, "%s\n", reset);
2916                break;
2917        case DIFF_STATUS_RENAMED:
2918                strbuf_addf(msg, "%s%ssimilarity index %d%%",
2919                            line_prefix, set, similarity_index(p));
2920                strbuf_addf(msg, "%s\n%s%srename from ",
2921                            reset, line_prefix, set);
2922                quote_c_style(name, msg, NULL, 0);
2923                strbuf_addf(msg, "%s\n%s%srename to ",
2924                            reset, line_prefix, set);
2925                quote_c_style(other, msg, NULL, 0);
2926                strbuf_addf(msg, "%s\n", reset);
2927                break;
2928        case DIFF_STATUS_MODIFIED:
2929                if (p->score) {
2930                        strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
2931                                    line_prefix,
2932                                    set, similarity_index(p), reset);
2933                        break;
2934                }
2935                /* fallthru */
2936        default:
2937                *must_show_header = 0;
2938        }
2939        if (one && two && hashcmp(one->sha1, two->sha1)) {
2940                int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
2941
2942                if (DIFF_OPT_TST(o, BINARY)) {
2943                        mmfile_t mf;
2944                        if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
2945                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
2946                                abbrev = 40;
2947                }
2948                strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
2949                            find_unique_abbrev(one->sha1, abbrev));
2950                strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
2951                if (one->mode == two->mode)
2952                        strbuf_addf(msg, " %06o", one->mode);
2953                strbuf_addf(msg, "%s\n", reset);
2954        }
2955}
2956
2957static void run_diff_cmd(const char *pgm,
2958                         const char *name,
2959                         const char *other,
2960                         const char *attr_path,
2961                         struct diff_filespec *one,
2962                         struct diff_filespec *two,
2963                         struct strbuf *msg,
2964                         struct diff_options *o,
2965                         struct diff_filepair *p)
2966{
2967        const char *xfrm_msg = NULL;
2968        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
2969        int must_show_header = 0;
2970
2971        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
2972                pgm = NULL;
2973        else {
2974                struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
2975                if (drv && drv->external)
2976                        pgm = drv->external;
2977        }
2978
2979        if (msg) {
2980                /*
2981                 * don't use colors when the header is intended for an
2982                 * external diff driver
2983                 */
2984                fill_metainfo(msg, name, other, one, two, o, p,
2985                              &must_show_header,
2986                              want_color(o->use_color) && !pgm);
2987                xfrm_msg = msg->len ? msg->buf : NULL;
2988        }
2989
2990        if (pgm) {
2991                run_external_diff(pgm, name, other, one, two, xfrm_msg,
2992                                  complete_rewrite);
2993                return;
2994        }
2995        if (one && two)
2996                builtin_diff(name, other ? other : name,
2997                             one, two, xfrm_msg, must_show_header,
2998                             o, complete_rewrite);
2999        else
3000                fprintf(o->file, "* Unmerged path %s\n", name);
3001}
3002
3003static void diff_fill_sha1_info(struct diff_filespec *one)
3004{
3005        if (DIFF_FILE_VALID(one)) {
3006                if (!one->sha1_valid) {
3007                        struct stat st;
3008                        if (!strcmp(one->path, "-")) {
3009                                hashcpy(one->sha1, null_sha1);
3010                                return;
3011                        }
3012                        if (lstat(one->path, &st) < 0)
3013                                die_errno("stat '%s'", one->path);
3014                        if (index_path(one->sha1, one->path, &st, 0))
3015                                die("cannot hash %s", one->path);
3016                }
3017        }
3018        else
3019                hashclr(one->sha1);
3020}
3021
3022static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3023{
3024        /* Strip the prefix but do not molest /dev/null and absolute paths */
3025        if (*namep && **namep != '/') {
3026                *namep += prefix_length;
3027                if (**namep == '/')
3028                        ++*namep;
3029        }
3030        if (*otherp && **otherp != '/') {
3031                *otherp += prefix_length;
3032                if (**otherp == '/')
3033                        ++*otherp;
3034        }
3035}
3036
3037static void run_diff(struct diff_filepair *p, struct diff_options *o)
3038{
3039        const char *pgm = external_diff();
3040        struct strbuf msg;
3041        struct diff_filespec *one = p->one;
3042        struct diff_filespec *two = p->two;
3043        const char *name;
3044        const char *other;
3045        const char *attr_path;
3046
3047        name  = p->one->path;
3048        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3049        attr_path = name;
3050        if (o->prefix_length)
3051                strip_prefix(o->prefix_length, &name, &other);
3052
3053        if (DIFF_PAIR_UNMERGED(p)) {
3054                run_diff_cmd(pgm, name, NULL, attr_path,
3055                             NULL, NULL, NULL, o, p);
3056                return;
3057        }
3058
3059        diff_fill_sha1_info(one);
3060        diff_fill_sha1_info(two);
3061
3062        if (!pgm &&
3063            DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3064            (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3065                /*
3066                 * a filepair that changes between file and symlink
3067                 * needs to be split into deletion and creation.
3068                 */
3069                struct diff_filespec *null = alloc_filespec(two->path);
3070                run_diff_cmd(NULL, name, other, attr_path,
3071                             one, null, &msg, o, p);
3072                free(null);
3073                strbuf_release(&msg);
3074
3075                null = alloc_filespec(one->path);
3076                run_diff_cmd(NULL, name, other, attr_path,
3077                             null, two, &msg, o, p);
3078                free(null);
3079        }
3080        else
3081                run_diff_cmd(pgm, name, other, attr_path,
3082                             one, two, &msg, o, p);
3083
3084        strbuf_release(&msg);
3085}
3086
3087static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3088                         struct diffstat_t *diffstat)
3089{
3090        const char *name;
3091        const char *other;
3092        int complete_rewrite = 0;
3093
3094        if (DIFF_PAIR_UNMERGED(p)) {
3095                /* unmerged */
3096                builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, 0);
3097                return;
3098        }
3099
3100        name = p->one->path;
3101        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3102
3103        if (o->prefix_length)
3104                strip_prefix(o->prefix_length, &name, &other);
3105
3106        diff_fill_sha1_info(p->one);
3107        diff_fill_sha1_info(p->two);
3108
3109        if (p->status == DIFF_STATUS_MODIFIED && p->score)
3110                complete_rewrite = 1;
3111        builtin_diffstat(name, other, p->one, p->two, diffstat, o, complete_rewrite);
3112}
3113
3114static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3115{
3116        const char *name;
3117        const char *other;
3118        const char *attr_path;
3119
3120        if (DIFF_PAIR_UNMERGED(p)) {
3121                /* unmerged */
3122                return;
3123        }
3124
3125        name = p->one->path;
3126        other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3127        attr_path = other ? other : name;
3128
3129        if (o->prefix_length)
3130                strip_prefix(o->prefix_length, &name, &other);
3131
3132        diff_fill_sha1_info(p->one);
3133        diff_fill_sha1_info(p->two);
3134
3135        builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3136}
3137
3138void diff_setup(struct diff_options *options)
3139{
3140        memcpy(options, &default_diff_options, sizeof(*options));
3141
3142        options->file = stdout;
3143
3144        options->line_termination = '\n';
3145        options->break_opt = -1;
3146        options->rename_limit = -1;
3147        options->dirstat_permille = diff_dirstat_permille_default;
3148        options->context = 3;
3149        DIFF_OPT_SET(options, RENAME_EMPTY);
3150
3151        options->change = diff_change;
3152        options->add_remove = diff_addremove;
3153        options->use_color = diff_use_color_default;
3154        options->detect_rename = diff_detect_rename_default;
3155
3156        if (diff_no_prefix) {
3157                options->a_prefix = options->b_prefix = "";
3158        } else if (!diff_mnemonic_prefix) {
3159                options->a_prefix = "a/";
3160                options->b_prefix = "b/";
3161        }
3162}
3163
3164int diff_setup_done(struct diff_options *options)
3165{
3166        int count = 0;
3167
3168        if (options->output_format & DIFF_FORMAT_NAME)
3169                count++;
3170        if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3171                count++;
3172        if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3173                count++;
3174        if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3175                count++;
3176        if (count > 1)
3177                die("--name-only, --name-status, --check and -s are mutually exclusive");
3178
3179        /*
3180         * Most of the time we can say "there are changes"
3181         * only by checking if there are changed paths, but
3182         * --ignore-whitespace* options force us to look
3183         * inside contents.
3184         */
3185
3186        if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3187            DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3188            DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3189                DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3190        else
3191                DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3192
3193        if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3194                options->detect_rename = DIFF_DETECT_COPY;
3195
3196        if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3197                options->prefix = NULL;
3198        if (options->prefix)
3199                options->prefix_length = strlen(options->prefix);
3200        else
3201                options->prefix_length = 0;
3202
3203        if (options->output_format & (DIFF_FORMAT_NAME |
3204                                      DIFF_FORMAT_NAME_STATUS |
3205                                      DIFF_FORMAT_CHECKDIFF |
3206                                      DIFF_FORMAT_NO_OUTPUT))
3207                options->output_format &= ~(DIFF_FORMAT_RAW |
3208                                            DIFF_FORMAT_NUMSTAT |
3209                                            DIFF_FORMAT_DIFFSTAT |
3210                                            DIFF_FORMAT_SHORTSTAT |
3211                                            DIFF_FORMAT_DIRSTAT |
3212                                            DIFF_FORMAT_SUMMARY |
3213                                            DIFF_FORMAT_PATCH);
3214
3215        /*
3216         * These cases always need recursive; we do not drop caller-supplied
3217         * recursive bits for other formats here.
3218         */
3219        if (options->output_format & (DIFF_FORMAT_PATCH |
3220                                      DIFF_FORMAT_NUMSTAT |
3221                                      DIFF_FORMAT_DIFFSTAT |
3222                                      DIFF_FORMAT_SHORTSTAT |
3223                                      DIFF_FORMAT_DIRSTAT |
3224                                      DIFF_FORMAT_SUMMARY |
3225                                      DIFF_FORMAT_CHECKDIFF))
3226                DIFF_OPT_SET(options, RECURSIVE);
3227        /*
3228         * Also pickaxe would not work very well if you do not say recursive
3229         */
3230        if (options->pickaxe)
3231                DIFF_OPT_SET(options, RECURSIVE);
3232        /*
3233         * When patches are generated, submodules diffed against the work tree
3234         * must be checked for dirtiness too so it can be shown in the output
3235         */
3236        if (options->output_format & DIFF_FORMAT_PATCH)
3237                DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3238
3239        if (options->detect_rename && options->rename_limit < 0)
3240                options->rename_limit = diff_rename_limit_default;
3241        if (options->setup & DIFF_SETUP_USE_CACHE) {
3242                if (!active_cache)
3243                        /* read-cache does not die even when it fails
3244                         * so it is safe for us to do this here.  Also
3245                         * it does not smudge active_cache or active_nr
3246                         * when it fails, so we do not have to worry about
3247                         * cleaning it up ourselves either.
3248                         */
3249                        read_cache();
3250        }
3251        if (options->abbrev <= 0 || 40 < options->abbrev)
3252                options->abbrev = 40; /* full */
3253
3254        /*
3255         * It does not make sense to show the first hit we happened
3256         * to have found.  It does not make sense not to return with
3257         * exit code in such a case either.
3258         */
3259        if (DIFF_OPT_TST(options, QUICK)) {
3260                options->output_format = DIFF_FORMAT_NO_OUTPUT;
3261                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3262        }
3263
3264        return 0;
3265}
3266
3267static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3268{
3269        char c, *eq;
3270        int len;
3271
3272        if (*arg != '-')
3273                return 0;
3274        c = *++arg;
3275        if (!c)
3276                return 0;
3277        if (c == arg_short) {
3278                c = *++arg;
3279                if (!c)
3280                        return 1;
3281                if (val && isdigit(c)) {
3282                        char *end;
3283                        int n = strtoul(arg, &end, 10);
3284                        if (*end)
3285                                return 0;
3286                        *val = n;
3287                        return 1;
3288                }
3289                return 0;
3290        }
3291        if (c != '-')
3292                return 0;
3293        arg++;
3294        eq = strchr(arg, '=');
3295        if (eq)
3296                len = eq - arg;
3297        else
3298                len = strlen(arg);
3299        if (!len || strncmp(arg, arg_long, len))
3300                return 0;
3301        if (eq) {
3302                int n;
3303                char *end;
3304                if (!isdigit(*++eq))
3305                        return 0;
3306                n = strtoul(eq, &end, 10);
3307                if (*end)
3308                        return 0;
3309                *val = n;
3310        }
3311        return 1;
3312}
3313
3314static int diff_scoreopt_parse(const char *opt);
3315
3316static inline int short_opt(char opt, const char **argv,
3317                            const char **optarg)
3318{
3319        const char *arg = argv[0];
3320        if (arg[0] != '-' || arg[1] != opt)
3321                return 0;
3322        if (arg[2] != '\0') {
3323                *optarg = arg + 2;
3324                return 1;
3325        }
3326        if (!argv[1])
3327                die("Option '%c' requires a value", opt);
3328        *optarg = argv[1];
3329        return 2;
3330}
3331
3332int parse_long_opt(const char *opt, const char **argv,
3333                   const char **optarg)
3334{
3335        const char *arg = argv[0];
3336        if (arg[0] != '-' || arg[1] != '-')
3337                return 0;
3338        arg += strlen("--");
3339        if (prefixcmp(arg, opt))
3340                return 0;
3341        arg += strlen(opt);
3342        if (*arg == '=') { /* sticked form: --option=value */
3343                *optarg = arg + 1;
3344                return 1;
3345        }
3346        if (*arg != '\0')
3347                return 0;
3348        /* separate form: --option value */
3349        if (!argv[1])
3350                die("Option '--%s' requires a value", opt);
3351        *optarg = argv[1];
3352        return 2;
3353}
3354
3355static int stat_opt(struct diff_options *options, const char **av)
3356{
3357        const char *arg = av[0];
3358        char *end;
3359        int width = options->stat_width;
3360        int name_width = options->stat_name_width;
3361        int graph_width = options->stat_graph_width;
3362        int count = options->stat_count;
3363        int argcount = 1;
3364
3365        arg += strlen("--stat");
3366        end = (char *)arg;
3367
3368        switch (*arg) {
3369        case '-':
3370                if (!prefixcmp(arg, "-width")) {
3371                        arg += strlen("-width");
3372                        if (*arg == '=')
3373                                width = strtoul(arg + 1, &end, 10);
3374                        else if (!*arg && !av[1])
3375                                die("Option '--stat-width' requires a value");
3376                        else if (!*arg) {
3377                                width = strtoul(av[1], &end, 10);
3378                                argcount = 2;
3379                        }
3380                } else if (!prefixcmp(arg, "-name-width")) {
3381                        arg += strlen("-name-width");
3382                        if (*arg == '=')
3383                                name_width = strtoul(arg + 1, &end, 10);
3384                        else if (!*arg && !av[1])
3385                                die("Option '--stat-name-width' requires a value");
3386                        else if (!*arg) {
3387                                name_width = strtoul(av[1], &end, 10);
3388                                argcount = 2;
3389                        }
3390                } else if (!prefixcmp(arg, "-graph-width")) {
3391                        arg += strlen("-graph-width");
3392                        if (*arg == '=')
3393                                graph_width = strtoul(arg + 1, &end, 10);
3394                        else if (!*arg && !av[1])
3395                                die("Option '--stat-graph-width' requires a value");
3396                        else if (!*arg) {
3397                                graph_width = strtoul(av[1], &end, 10);
3398                                argcount = 2;
3399                        }
3400                } else if (!prefixcmp(arg, "-count")) {
3401                        arg += strlen("-count");
3402                        if (*arg == '=')
3403                                count = strtoul(arg + 1, &end, 10);
3404                        else if (!*arg && !av[1])
3405                                die("Option '--stat-count' requires a value");
3406                        else if (!*arg) {
3407                                count = strtoul(av[1], &end, 10);
3408                                argcount = 2;
3409                        }
3410                }
3411                break;
3412        case '=':
3413                width = strtoul(arg+1, &end, 10);
3414                if (*end == ',')
3415                        name_width = strtoul(end+1, &end, 10);
3416                if (*end == ',')
3417                        count = strtoul(end+1, &end, 10);
3418        }
3419
3420        /* Important! This checks all the error cases! */
3421        if (*end)
3422                return 0;
3423        options->output_format |= DIFF_FORMAT_DIFFSTAT;
3424        options->stat_name_width = name_width;
3425        options->stat_graph_width = graph_width;
3426        options->stat_width = width;
3427        options->stat_count = count;
3428        return argcount;
3429}
3430
3431static int parse_dirstat_opt(struct diff_options *options, const char *params)
3432{
3433        struct strbuf errmsg = STRBUF_INIT;
3434        if (parse_dirstat_params(options, params, &errmsg))
3435                die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3436                    errmsg.buf);
3437        strbuf_release(&errmsg);
3438        /*
3439         * The caller knows a dirstat-related option is given from the command
3440         * line; allow it to say "return this_function();"
3441         */
3442        options->output_format |= DIFF_FORMAT_DIRSTAT;
3443        return 1;
3444}
3445
3446int diff_opt_parse(struct diff_options *options, const char **av, int ac)
3447{
3448        const char *arg = av[0];
3449        const char *optarg;
3450        int argcount;
3451
3452        /* Output format options */
3453        if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch"))
3454                options->output_format |= DIFF_FORMAT_PATCH;
3455        else if (opt_arg(arg, 'U', "unified", &options->context))
3456                options->output_format |= DIFF_FORMAT_PATCH;
3457        else if (!strcmp(arg, "--raw"))
3458                options->output_format |= DIFF_FORMAT_RAW;
3459        else if (!strcmp(arg, "--patch-with-raw"))
3460                options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
3461        else if (!strcmp(arg, "--numstat"))
3462                options->output_format |= DIFF_FORMAT_NUMSTAT;
3463        else if (!strcmp(arg, "--shortstat"))
3464                options->output_format |= DIFF_FORMAT_SHORTSTAT;
3465        else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3466                return parse_dirstat_opt(options, "");
3467        else if (!prefixcmp(arg, "-X"))
3468                return parse_dirstat_opt(options, arg + 2);
3469        else if (!prefixcmp(arg, "--dirstat="))
3470                return parse_dirstat_opt(options, arg + 10);
3471        else if (!strcmp(arg, "--cumulative"))
3472                return parse_dirstat_opt(options, "cumulative");
3473        else if (!strcmp(arg, "--dirstat-by-file"))
3474                return parse_dirstat_opt(options, "files");
3475        else if (!prefixcmp(arg, "--dirstat-by-file=")) {
3476                parse_dirstat_opt(options, "files");
3477                return parse_dirstat_opt(options, arg + 18);
3478        }
3479        else if (!strcmp(arg, "--check"))
3480                options->output_format |= DIFF_FORMAT_CHECKDIFF;
3481        else if (!strcmp(arg, "--summary"))
3482                options->output_format |= DIFF_FORMAT_SUMMARY;
3483        else if (!strcmp(arg, "--patch-with-stat"))
3484                options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
3485        else if (!strcmp(arg, "--name-only"))
3486                options->output_format |= DIFF_FORMAT_NAME;
3487        else if (!strcmp(arg, "--name-status"))
3488                options->output_format |= DIFF_FORMAT_NAME_STATUS;
3489        else if (!strcmp(arg, "-s"))
3490                options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3491        else if (!prefixcmp(arg, "--stat"))
3492                /* --stat, --stat-width, --stat-name-width, or --stat-count */
3493                return stat_opt(options, av);
3494
3495        /* renames options */
3496        else if (!prefixcmp(arg, "-B") || !prefixcmp(arg, "--break-rewrites=") ||
3497                 !strcmp(arg, "--break-rewrites")) {
3498                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3499                        return error("invalid argument to -B: %s", arg+2);
3500        }
3501        else if (!prefixcmp(arg, "-M") || !prefixcmp(arg, "--find-renames=") ||
3502                 !strcmp(arg, "--find-renames")) {
3503                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3504                        return error("invalid argument to -M: %s", arg+2);
3505                options->detect_rename = DIFF_DETECT_RENAME;
3506        }
3507        else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3508                options->irreversible_delete = 1;
3509        }
3510        else if (!prefixcmp(arg, "-C") || !prefixcmp(arg, "--find-copies=") ||
3511                 !strcmp(arg, "--find-copies")) {
3512                if (options->detect_rename == DIFF_DETECT_COPY)
3513                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3514                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3515                        return error("invalid argument to -C: %s", arg+2);
3516                options->detect_rename = DIFF_DETECT_COPY;
3517        }
3518        else if (!strcmp(arg, "--no-renames"))
3519                options->detect_rename = 0;
3520        else if (!strcmp(arg, "--rename-empty"))
3521                DIFF_OPT_SET(options, RENAME_EMPTY);
3522        else if (!strcmp(arg, "--no-rename-empty"))
3523                DIFF_OPT_CLR(options, RENAME_EMPTY);
3524        else if (!strcmp(arg, "--relative"))
3525                DIFF_OPT_SET(options, RELATIVE_NAME);
3526        else if (!prefixcmp(arg, "--relative=")) {
3527                DIFF_OPT_SET(options, RELATIVE_NAME);
3528                options->prefix = arg + 11;
3529        }
3530
3531        /* xdiff options */
3532        else if (!strcmp(arg, "--minimal"))
3533                DIFF_XDL_SET(options, NEED_MINIMAL);
3534        else if (!strcmp(arg, "--no-minimal"))
3535                DIFF_XDL_CLR(options, NEED_MINIMAL);
3536        else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3537                DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3538        else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3539                DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3540        else if (!strcmp(arg, "--ignore-space-at-eol"))
3541                DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3542        else if (!strcmp(arg, "--patience"))
3543                options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3544        else if (!strcmp(arg, "--histogram"))
3545                options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3546
3547        /* flags options */
3548        else if (!strcmp(arg, "--binary")) {
3549                options->output_format |= DIFF_FORMAT_PATCH;
3550                DIFF_OPT_SET(options, BINARY);
3551        }
3552        else if (!strcmp(arg, "--full-index"))
3553                DIFF_OPT_SET(options, FULL_INDEX);
3554        else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3555                DIFF_OPT_SET(options, TEXT);
3556        else if (!strcmp(arg, "-R"))
3557                DIFF_OPT_SET(options, REVERSE_DIFF);
3558        else if (!strcmp(arg, "--find-copies-harder"))
3559                DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3560        else if (!strcmp(arg, "--follow"))
3561                DIFF_OPT_SET(options, FOLLOW_RENAMES);
3562        else if (!strcmp(arg, "--color"))
3563                options->use_color = 1;
3564        else if (!prefixcmp(arg, "--color=")) {
3565                int value = git_config_colorbool(NULL, arg+8);
3566                if (value < 0)
3567                        return error("option `color' expects \"always\", \"auto\", or \"never\"");
3568                options->use_color = value;
3569        }
3570        else if (!strcmp(arg, "--no-color"))
3571                options->use_color = 0;
3572        else if (!strcmp(arg, "--color-words")) {
3573                options->use_color = 1;
3574                options->word_diff = DIFF_WORDS_COLOR;
3575        }
3576        else if (!prefixcmp(arg, "--color-words=")) {
3577                options->use_color = 1;
3578                options->word_diff = DIFF_WORDS_COLOR;
3579                options->word_regex = arg + 14;
3580        }
3581        else if (!strcmp(arg, "--word-diff")) {
3582                if (options->word_diff == DIFF_WORDS_NONE)
3583                        options->word_diff = DIFF_WORDS_PLAIN;
3584        }
3585        else if (!prefixcmp(arg, "--word-diff=")) {
3586                const char *type = arg + 12;
3587                if (!strcmp(type, "plain"))
3588                        options->word_diff = DIFF_WORDS_PLAIN;
3589                else if (!strcmp(type, "color")) {
3590                        options->use_color = 1;
3591                        options->word_diff = DIFF_WORDS_COLOR;
3592                }
3593                else if (!strcmp(type, "porcelain"))
3594                        options->word_diff = DIFF_WORDS_PORCELAIN;
3595                else if (!strcmp(type, "none"))
3596                        options->word_diff = DIFF_WORDS_NONE;
3597                else
3598                        die("bad --word-diff argument: %s", type);
3599        }
3600        else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3601                if (options->word_diff == DIFF_WORDS_NONE)
3602                        options->word_diff = DIFF_WORDS_PLAIN;
3603                options->word_regex = optarg;
3604                return argcount;
3605        }
3606        else if (!strcmp(arg, "--exit-code"))
3607                DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3608        else if (!strcmp(arg, "--quiet"))
3609                DIFF_OPT_SET(options, QUICK);
3610        else if (!strcmp(arg, "--ext-diff"))
3611                DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3612        else if (!strcmp(arg, "--no-ext-diff"))
3613                DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3614        else if (!strcmp(arg, "--textconv"))
3615                DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3616        else if (!strcmp(arg, "--no-textconv"))
3617                DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3618        else if (!strcmp(arg, "--ignore-submodules")) {
3619                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3620                handle_ignore_submodules_arg(options, "all");
3621        } else if (!prefixcmp(arg, "--ignore-submodules=")) {
3622                DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3623                handle_ignore_submodules_arg(options, arg + 20);
3624        } else if (!strcmp(arg, "--submodule"))
3625                DIFF_OPT_SET(options, SUBMODULE_LOG);
3626        else if (!prefixcmp(arg, "--submodule=")) {
3627                if (!strcmp(arg + 12, "log"))
3628                        DIFF_OPT_SET(options, SUBMODULE_LOG);
3629        }
3630
3631        /* misc options */
3632        else if (!strcmp(arg, "-z"))
3633                options->line_termination = 0;
3634        else if ((argcount = short_opt('l', av, &optarg))) {
3635                options->rename_limit = strtoul(optarg, NULL, 10);
3636                return argcount;
3637        }
3638        else if ((argcount = short_opt('S', av, &optarg))) {
3639                options->pickaxe = optarg;
3640                options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3641                return argcount;
3642        } else if ((argcount = short_opt('G', av, &optarg))) {
3643                options->pickaxe = optarg;
3644                options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3645                return argcount;
3646        }
3647        else if (!strcmp(arg, "--pickaxe-all"))
3648                options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3649        else if (!strcmp(arg, "--pickaxe-regex"))
3650                options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3651        else if ((argcount = short_opt('O', av, &optarg))) {
3652                options->orderfile = optarg;
3653                return argcount;
3654        }
3655        else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3656                options->filter = optarg;
3657                return argcount;
3658        }
3659        else if (!strcmp(arg, "--abbrev"))
3660                options->abbrev = DEFAULT_ABBREV;
3661        else if (!prefixcmp(arg, "--abbrev=")) {
3662                options->abbrev = strtoul(arg + 9, NULL, 10);
3663                if (options->abbrev < MINIMUM_ABBREV)
3664                        options->abbrev = MINIMUM_ABBREV;
3665                else if (40 < options->abbrev)
3666                        options->abbrev = 40;
3667        }
3668        else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3669                options->a_prefix = optarg;
3670                return argcount;
3671        }
3672        else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3673                options->b_prefix = optarg;
3674                return argcount;
3675        }
3676        else if (!strcmp(arg, "--no-prefix"))
3677                options->a_prefix = options->b_prefix = "";
3678        else if (opt_arg(arg, '\0', "inter-hunk-context",
3679                         &options->interhunkcontext))
3680                ;
3681        else if (!strcmp(arg, "-W"))
3682                DIFF_OPT_SET(options, FUNCCONTEXT);
3683        else if (!strcmp(arg, "--function-context"))
3684                DIFF_OPT_SET(options, FUNCCONTEXT);
3685        else if (!strcmp(arg, "--no-function-context"))
3686                DIFF_OPT_CLR(options, FUNCCONTEXT);
3687        else if ((argcount = parse_long_opt("output", av, &optarg))) {
3688                options->file = fopen(optarg, "w");
3689                if (!options->file)
3690                        die_errno("Could not open '%s'", optarg);
3691                options->close_file = 1;
3692                return argcount;
3693        } else
3694                return 0;
3695        return 1;
3696}
3697
3698int parse_rename_score(const char **cp_p)
3699{
3700        unsigned long num, scale;
3701        int ch, dot;
3702        const char *cp = *cp_p;
3703
3704        num = 0;
3705        scale = 1;
3706        dot = 0;
3707        for (;;) {
3708                ch = *cp;
3709                if ( !dot && ch == '.' ) {
3710                        scale = 1;
3711                        dot = 1;
3712                } else if ( ch == '%' ) {
3713                        scale = dot ? scale*100 : 100;
3714                        cp++;   /* % is always at the end */
3715                        break;
3716                } else if ( ch >= '0' && ch <= '9' ) {
3717                        if ( scale < 100000 ) {
3718                                scale *= 10;
3719                                num = (num*10) + (ch-'0');
3720                        }
3721                } else {
3722                        break;
3723                }
3724                cp++;
3725        }
3726        *cp_p = cp;
3727
3728        /* user says num divided by scale and we say internally that
3729         * is MAX_SCORE * num / scale.
3730         */
3731        return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
3732}
3733
3734static int diff_scoreopt_parse(const char *opt)
3735{
3736        int opt1, opt2, cmd;
3737
3738        if (*opt++ != '-')
3739                return -1;
3740        cmd = *opt++;
3741        if (cmd == '-') {
3742                /* convert the long-form arguments into short-form versions */
3743                if (!prefixcmp(opt, "break-rewrites")) {
3744                        opt += strlen("break-rewrites");
3745                        if (*opt == 0 || *opt++ == '=')
3746                                cmd = 'B';
3747                } else if (!prefixcmp(opt, "find-copies")) {
3748                        opt += strlen("find-copies");
3749                        if (*opt == 0 || *opt++ == '=')
3750                                cmd = 'C';
3751                } else if (!prefixcmp(opt, "find-renames")) {
3752                        opt += strlen("find-renames");
3753                        if (*opt == 0 || *opt++ == '=')
3754                                cmd = 'M';
3755                }
3756        }
3757        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
3758                return -1; /* that is not a -M, -C nor -B option */
3759
3760        opt1 = parse_rename_score(&opt);
3761        if (cmd != 'B')
3762                opt2 = 0;
3763        else {
3764                if (*opt == 0)
3765                        opt2 = 0;
3766                else if (*opt != '/')
3767                        return -1; /* we expect -B80/99 or -B80 */
3768                else {
3769                        opt++;
3770                        opt2 = parse_rename_score(&opt);
3771                }
3772        }
3773        if (*opt != 0)
3774                return -1;
3775        return opt1 | (opt2 << 16);
3776}
3777
3778struct diff_queue_struct diff_queued_diff;
3779
3780void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
3781{
3782        if (queue->alloc <= queue->nr) {
3783                queue->alloc = alloc_nr(queue->alloc);
3784                queue->queue = xrealloc(queue->queue,
3785                                        sizeof(dp) * queue->alloc);
3786        }
3787        queue->queue[queue->nr++] = dp;
3788}
3789
3790struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
3791                                 struct diff_filespec *one,
3792                                 struct diff_filespec *two)
3793{
3794        struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
3795        dp->one = one;
3796        dp->two = two;
3797        if (queue)
3798                diff_q(queue, dp);
3799        return dp;
3800}
3801
3802void diff_free_filepair(struct diff_filepair *p)
3803{
3804        free_filespec(p->one);
3805        free_filespec(p->two);
3806        free(p);
3807}
3808
3809/* This is different from find_unique_abbrev() in that
3810 * it stuffs the result with dots for alignment.
3811 */
3812const char *diff_unique_abbrev(const unsigned char *sha1, int len)
3813{
3814        int abblen;
3815        const char *abbrev;
3816        if (len == 40)
3817                return sha1_to_hex(sha1);
3818
3819        abbrev = find_unique_abbrev(sha1, len);
3820        abblen = strlen(abbrev);
3821        if (abblen < 37) {
3822                static char hex[41];
3823                if (len < abblen && abblen <= len + 2)
3824                        sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
3825                else
3826                        sprintf(hex, "%s...", abbrev);
3827                return hex;
3828        }
3829        return sha1_to_hex(sha1);
3830}
3831
3832static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
3833{
3834        int line_termination = opt->line_termination;
3835        int inter_name_termination = line_termination ? '\t' : '\0';
3836        if (opt->output_prefix) {
3837                struct strbuf *msg = NULL;
3838                msg = opt->output_prefix(opt, opt->output_prefix_data);
3839                fprintf(opt->file, "%s", msg->buf);
3840        }
3841
3842        if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
3843                fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
3844                        diff_unique_abbrev(p->one->sha1, opt->abbrev));
3845                fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
3846        }
3847        if (p->score) {
3848                fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
3849                        inter_name_termination);
3850        } else {
3851                fprintf(opt->file, "%c%c", p->status, inter_name_termination);
3852        }
3853
3854        if (p->status == DIFF_STATUS_COPIED ||
3855            p->status == DIFF_STATUS_RENAMED) {
3856                const char *name_a, *name_b;
3857                name_a = p->one->path;
3858                name_b = p->two->path;
3859                strip_prefix(opt->prefix_length, &name_a, &name_b);
3860                write_name_quoted(name_a, opt->file, inter_name_termination);
3861                write_name_quoted(name_b, opt->file, line_termination);
3862        } else {
3863                const char *name_a, *name_b;
3864                name_a = p->one->mode ? p->one->path : p->two->path;
3865                name_b = NULL;
3866                strip_prefix(opt->prefix_length, &name_a, &name_b);
3867                write_name_quoted(name_a, opt->file, line_termination);
3868        }
3869}
3870
3871int diff_unmodified_pair(struct diff_filepair *p)
3872{
3873        /* This function is written stricter than necessary to support
3874         * the currently implemented transformers, but the idea is to
3875         * let transformers to produce diff_filepairs any way they want,
3876         * and filter and clean them up here before producing the output.
3877         */
3878        struct diff_filespec *one = p->one, *two = p->two;
3879
3880        if (DIFF_PAIR_UNMERGED(p))
3881                return 0; /* unmerged is interesting */
3882
3883        /* deletion, addition, mode or type change
3884         * and rename are all interesting.
3885         */
3886        if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
3887            DIFF_PAIR_MODE_CHANGED(p) ||
3888            strcmp(one->path, two->path))
3889                return 0;
3890
3891        /* both are valid and point at the same path.  that is, we are
3892         * dealing with a change.
3893         */
3894        if (one->sha1_valid && two->sha1_valid &&
3895            !hashcmp(one->sha1, two->sha1) &&
3896            !one->dirty_submodule && !two->dirty_submodule)
3897                return 1; /* no change */
3898        if (!one->sha1_valid && !two->sha1_valid)
3899                return 1; /* both look at the same file on the filesystem. */
3900        return 0;
3901}
3902
3903static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
3904{
3905        if (diff_unmodified_pair(p))
3906                return;
3907
3908        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3909            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3910                return; /* no tree diffs in patch format */
3911
3912        run_diff(p, o);
3913}
3914
3915static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
3916                            struct diffstat_t *diffstat)
3917{
3918        if (diff_unmodified_pair(p))
3919                return;
3920
3921        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3922            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3923                return; /* no useful stat for tree diffs */
3924
3925        run_diffstat(p, o, diffstat);
3926}
3927
3928static void diff_flush_checkdiff(struct diff_filepair *p,
3929                struct diff_options *o)
3930{
3931        if (diff_unmodified_pair(p))
3932                return;
3933
3934        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3935            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3936                return; /* nothing to check in tree diffs */
3937
3938        run_checkdiff(p, o);
3939}
3940
3941int diff_queue_is_empty(void)
3942{
3943        struct diff_queue_struct *q = &diff_queued_diff;
3944        int i;
3945        for (i = 0; i < q->nr; i++)
3946                if (!diff_unmodified_pair(q->queue[i]))
3947                        return 0;
3948        return 1;
3949}
3950
3951#if DIFF_DEBUG
3952void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
3953{
3954        fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
3955                x, one ? one : "",
3956                s->path,
3957                DIFF_FILE_VALID(s) ? "valid" : "invalid",
3958                s->mode,
3959                s->sha1_valid ? sha1_to_hex(s->sha1) : "");
3960        fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
3961                x, one ? one : "",
3962                s->size, s->xfrm_flags);
3963}
3964
3965void diff_debug_filepair(const struct diff_filepair *p, int i)
3966{
3967        diff_debug_filespec(p->one, i, "one");
3968        diff_debug_filespec(p->two, i, "two");
3969        fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
3970                p->score, p->status ? p->status : '?',
3971                p->one->rename_used, p->broken_pair);
3972}
3973
3974void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
3975{
3976        int i;
3977        if (msg)
3978                fprintf(stderr, "%s\n", msg);
3979        fprintf(stderr, "q->nr = %d\n", q->nr);
3980        for (i = 0; i < q->nr; i++) {
3981                struct diff_filepair *p = q->queue[i];
3982                diff_debug_filepair(p, i);
3983        }
3984}
3985#endif
3986
3987static void diff_resolve_rename_copy(void)
3988{
3989        int i;
3990        struct diff_filepair *p;
3991        struct diff_queue_struct *q = &diff_queued_diff;
3992
3993        diff_debug_queue("resolve-rename-copy", q);
3994
3995        for (i = 0; i < q->nr; i++) {
3996                p = q->queue[i];
3997                p->status = 0; /* undecided */
3998                if (DIFF_PAIR_UNMERGED(p))
3999                        p->status = DIFF_STATUS_UNMERGED;
4000                else if (!DIFF_FILE_VALID(p->one))
4001                        p->status = DIFF_STATUS_ADDED;
4002                else if (!DIFF_FILE_VALID(p->two))
4003                        p->status = DIFF_STATUS_DELETED;
4004                else if (DIFF_PAIR_TYPE_CHANGED(p))
4005                        p->status = DIFF_STATUS_TYPE_CHANGED;
4006
4007                /* from this point on, we are dealing with a pair
4008                 * whose both sides are valid and of the same type, i.e.
4009                 * either in-place edit or rename/copy edit.
4010                 */
4011                else if (DIFF_PAIR_RENAME(p)) {
4012                        /*
4013                         * A rename might have re-connected a broken
4014                         * pair up, causing the pathnames to be the
4015                         * same again. If so, that's not a rename at
4016                         * all, just a modification..
4017                         *
4018                         * Otherwise, see if this source was used for
4019                         * multiple renames, in which case we decrement
4020                         * the count, and call it a copy.
4021                         */
4022                        if (!strcmp(p->one->path, p->two->path))
4023                                p->status = DIFF_STATUS_MODIFIED;
4024                        else if (--p->one->rename_used > 0)
4025                                p->status = DIFF_STATUS_COPIED;
4026                        else
4027                                p->status = DIFF_STATUS_RENAMED;
4028                }
4029                else if (hashcmp(p->one->sha1, p->two->sha1) ||
4030                         p->one->mode != p->two->mode ||
4031                         p->one->dirty_submodule ||
4032                         p->two->dirty_submodule ||
4033                         is_null_sha1(p->one->sha1))
4034                        p->status = DIFF_STATUS_MODIFIED;
4035                else {
4036                        /* This is a "no-change" entry and should not
4037                         * happen anymore, but prepare for broken callers.
4038                         */
4039                        error("feeding unmodified %s to diffcore",
4040                              p->one->path);
4041                        p->status = DIFF_STATUS_UNKNOWN;
4042                }
4043        }
4044        diff_debug_queue("resolve-rename-copy done", q);
4045}
4046
4047static int check_pair_status(struct diff_filepair *p)
4048{
4049        switch (p->status) {
4050        case DIFF_STATUS_UNKNOWN:
4051                return 0;
4052        case 0:
4053                die("internal error in diff-resolve-rename-copy");
4054        default:
4055                return 1;
4056        }
4057}
4058
4059static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4060{
4061        int fmt = opt->output_format;
4062
4063        if (fmt & DIFF_FORMAT_CHECKDIFF)
4064                diff_flush_checkdiff(p, opt);
4065        else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4066                diff_flush_raw(p, opt);
4067        else if (fmt & DIFF_FORMAT_NAME) {
4068                const char *name_a, *name_b;
4069                name_a = p->two->path;
4070                name_b = NULL;
4071                strip_prefix(opt->prefix_length, &name_a, &name_b);
4072                write_name_quoted(name_a, opt->file, opt->line_termination);
4073        }
4074}
4075
4076static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4077{
4078        if (fs->mode)
4079                fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4080        else
4081                fprintf(file, " %s ", newdelete);
4082        write_name_quoted(fs->path, file, '\n');
4083}
4084
4085
4086static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4087                const char *line_prefix)
4088{
4089        if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4090                fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4091                        p->two->mode, show_name ? ' ' : '\n');
4092                if (show_name) {
4093                        write_name_quoted(p->two->path, file, '\n');
4094                }
4095        }
4096}
4097
4098static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4099                        const char *line_prefix)
4100{
4101        char *names = pprint_rename(p->one->path, p->two->path);
4102
4103        fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4104        free(names);
4105        show_mode_change(file, p, 0, line_prefix);
4106}
4107
4108static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4109{
4110        FILE *file = opt->file;
4111        char *line_prefix = "";
4112
4113        if (opt->output_prefix) {
4114                struct strbuf *buf = opt->output_prefix(opt, opt->output_prefix_data);
4115                line_prefix = buf->buf;
4116        }
4117
4118        switch(p->status) {
4119        case DIFF_STATUS_DELETED:
4120                fputs(line_prefix, file);
4121                show_file_mode_name(file, "delete", p->one);
4122                break;
4123        case DIFF_STATUS_ADDED:
4124                fputs(line_prefix, file);
4125                show_file_mode_name(file, "create", p->two);
4126                break;
4127        case DIFF_STATUS_COPIED:
4128                fputs(line_prefix, file);
4129                show_rename_copy(file, "copy", p, line_prefix);
4130                break;
4131        case DIFF_STATUS_RENAMED:
4132                fputs(line_prefix, file);
4133                show_rename_copy(file, "rename", p, line_prefix);
4134                break;
4135        default:
4136                if (p->score) {
4137                        fprintf(file, "%s rewrite ", line_prefix);
4138                        write_name_quoted(p->two->path, file, ' ');
4139                        fprintf(file, "(%d%%)\n", similarity_index(p));
4140                }
4141                show_mode_change(file, p, !p->score, line_prefix);
4142                break;
4143        }
4144}
4145
4146struct patch_id_t {
4147        git_SHA_CTX *ctx;
4148        int patchlen;
4149};
4150
4151static int remove_space(char *line, int len)
4152{
4153        int i;
4154        char *dst = line;
4155        unsigned char c;
4156
4157        for (i = 0; i < len; i++)
4158                if (!isspace((c = line[i])))
4159                        *dst++ = c;
4160
4161        return dst - line;
4162}
4163
4164static void patch_id_consume(void *priv, char *line, unsigned long len)
4165{
4166        struct patch_id_t *data = priv;
4167        int new_len;
4168
4169        /* Ignore line numbers when computing the SHA1 of the patch */
4170        if (!prefixcmp(line, "@@ -"))
4171                return;
4172
4173        new_len = remove_space(line, len);
4174
4175        git_SHA1_Update(data->ctx, line, new_len);
4176        data->patchlen += new_len;
4177}
4178
4179/* returns 0 upon success, and writes result into sha1 */
4180static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
4181{
4182        struct diff_queue_struct *q = &diff_queued_diff;
4183        int i;
4184        git_SHA_CTX ctx;
4185        struct patch_id_t data;
4186        char buffer[PATH_MAX * 4 + 20];
4187
4188        git_SHA1_Init(&ctx);
4189        memset(&data, 0, sizeof(struct patch_id_t));
4190        data.ctx = &ctx;
4191
4192        for (i = 0; i < q->nr; i++) {
4193                xpparam_t xpp;
4194                xdemitconf_t xecfg;
4195                mmfile_t mf1, mf2;
4196                struct diff_filepair *p = q->queue[i];
4197                int len1, len2;
4198
4199                memset(&xpp, 0, sizeof(xpp));
4200                memset(&xecfg, 0, sizeof(xecfg));
4201                if (p->status == 0)
4202                        return error("internal diff status error");
4203                if (p->status == DIFF_STATUS_UNKNOWN)
4204                        continue;
4205                if (diff_unmodified_pair(p))
4206                        continue;
4207                if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4208                    (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4209                        continue;
4210                if (DIFF_PAIR_UNMERGED(p))
4211                        continue;
4212
4213                diff_fill_sha1_info(p->one);
4214                diff_fill_sha1_info(p->two);
4215                if (fill_mmfile(&mf1, p->one) < 0 ||
4216                                fill_mmfile(&mf2, p->two) < 0)
4217                        return error("unable to read files to diff");
4218
4219                len1 = remove_space(p->one->path, strlen(p->one->path));
4220                len2 = remove_space(p->two->path, strlen(p->two->path));
4221                if (p->one->mode == 0)
4222                        len1 = snprintf(buffer, sizeof(buffer),
4223                                        "diff--gita/%.*sb/%.*s"
4224                                        "newfilemode%06o"
4225                                        "---/dev/null"
4226                                        "+++b/%.*s",
4227                                        len1, p->one->path,
4228                                        len2, p->two->path,
4229                                        p->two->mode,
4230                                        len2, p->two->path);
4231                else if (p->two->mode == 0)
4232                        len1 = snprintf(buffer, sizeof(buffer),
4233                                        "diff--gita/%.*sb/%.*s"
4234                                        "deletedfilemode%06o"
4235                                        "---a/%.*s"
4236                                        "+++/dev/null",
4237                                        len1, p->one->path,
4238                                        len2, p->two->path,
4239                                        p->one->mode,
4240                                        len1, p->one->path);
4241                else
4242                        len1 = snprintf(buffer, sizeof(buffer),
4243                                        "diff--gita/%.*sb/%.*s"
4244                                        "---a/%.*s"
4245                                        "+++b/%.*s",
4246                                        len1, p->one->path,
4247                                        len2, p->two->path,
4248                                        len1, p->one->path,
4249                                        len2, p->two->path);
4250                git_SHA1_Update(&ctx, buffer, len1);
4251
4252                if (diff_filespec_is_binary(p->one) ||
4253                    diff_filespec_is_binary(p->two)) {
4254                        git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4255                        git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4256                        continue;
4257                }
4258
4259                xpp.flags = 0;
4260                xecfg.ctxlen = 3;
4261                xecfg.flags = 0;
4262                xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4263                              &xpp, &xecfg);
4264        }
4265
4266        git_SHA1_Final(sha1, &ctx);
4267        return 0;
4268}
4269
4270int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4271{
4272        struct diff_queue_struct *q = &diff_queued_diff;
4273        int i;
4274        int result = diff_get_patch_id(options, sha1);
4275
4276        for (i = 0; i < q->nr; i++)
4277                diff_free_filepair(q->queue[i]);
4278
4279        free(q->queue);
4280        DIFF_QUEUE_CLEAR(q);
4281
4282        return result;
4283}
4284
4285static int is_summary_empty(const struct diff_queue_struct *q)
4286{
4287        int i;
4288
4289        for (i = 0; i < q->nr; i++) {
4290                const struct diff_filepair *p = q->queue[i];
4291
4292                switch (p->status) {
4293                case DIFF_STATUS_DELETED:
4294                case DIFF_STATUS_ADDED:
4295                case DIFF_STATUS_COPIED:
4296                case DIFF_STATUS_RENAMED:
4297                        return 0;
4298                default:
4299                        if (p->score)
4300                                return 0;
4301                        if (p->one->mode && p->two->mode &&
4302                            p->one->mode != p->two->mode)
4303                                return 0;
4304                        break;
4305                }
4306        }
4307        return 1;
4308}
4309
4310static const char rename_limit_warning[] =
4311"inexact rename detection was skipped due to too many files.";
4312
4313static const char degrade_cc_to_c_warning[] =
4314"only found copies from modified paths due to too many files.";
4315
4316static const char rename_limit_advice[] =
4317"you may want to set your %s variable to at least "
4318"%d and retry the command.";
4319
4320void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4321{
4322        if (degraded_cc)
4323                warning(degrade_cc_to_c_warning);
4324        else if (needed)
4325                warning(rename_limit_warning);
4326        else
4327                return;
4328        if (0 < needed && needed < 32767)
4329                warning(rename_limit_advice, varname, needed);
4330}
4331
4332void diff_flush(struct diff_options *options)
4333{
4334        struct diff_queue_struct *q = &diff_queued_diff;
4335        int i, output_format = options->output_format;
4336        int separator = 0;
4337        int dirstat_by_line = 0;
4338
4339        /*
4340         * Order: raw, stat, summary, patch
4341         * or:    name/name-status/checkdiff (other bits clear)
4342         */
4343        if (!q->nr)
4344                goto free_queue;
4345
4346        if (output_format & (DIFF_FORMAT_RAW |
4347                             DIFF_FORMAT_NAME |
4348                             DIFF_FORMAT_NAME_STATUS |
4349                             DIFF_FORMAT_CHECKDIFF)) {
4350                for (i = 0; i < q->nr; i++) {
4351                        struct diff_filepair *p = q->queue[i];
4352                        if (check_pair_status(p))
4353                                flush_one_pair(p, options);
4354                }
4355                separator++;
4356        }
4357
4358        if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4359                dirstat_by_line = 1;
4360
4361        if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4362            dirstat_by_line) {
4363                struct diffstat_t diffstat;
4364
4365                memset(&diffstat, 0, sizeof(struct diffstat_t));
4366                for (i = 0; i < q->nr; i++) {
4367                        struct diff_filepair *p = q->queue[i];
4368                        if (check_pair_status(p))
4369                                diff_flush_stat(p, options, &diffstat);
4370                }
4371                if (output_format & DIFF_FORMAT_NUMSTAT)
4372                        show_numstat(&diffstat, options);
4373                if (output_format & DIFF_FORMAT_DIFFSTAT)
4374                        show_stats(&diffstat, options);
4375                if (output_format & DIFF_FORMAT_SHORTSTAT)
4376                        show_shortstats(&diffstat, options);
4377                if (output_format & DIFF_FORMAT_DIRSTAT)
4378                        show_dirstat_by_line(&diffstat, options);
4379                free_diffstat_info(&diffstat);
4380                separator++;
4381        }
4382        if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4383                show_dirstat(options);
4384
4385        if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4386                for (i = 0; i < q->nr; i++) {
4387                        diff_summary(options, q->queue[i]);
4388                }
4389                separator++;
4390        }
4391
4392        if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4393            DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4394            DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4395                /*
4396                 * run diff_flush_patch for the exit status. setting
4397                 * options->file to /dev/null should be safe, becaue we
4398                 * aren't supposed to produce any output anyway.
4399                 */
4400                if (options->close_file)
4401                        fclose(options->file);
4402                options->file = fopen("/dev/null", "w");
4403                if (!options->file)
4404                        die_errno("Could not open /dev/null");
4405                options->close_file = 1;
4406                for (i = 0; i < q->nr; i++) {
4407                        struct diff_filepair *p = q->queue[i];
4408                        if (check_pair_status(p))
4409                                diff_flush_patch(p, options);
4410                        if (options->found_changes)
4411                                break;
4412                }
4413        }
4414
4415        if (output_format & DIFF_FORMAT_PATCH) {
4416                if (separator) {
4417                        if (options->output_prefix) {
4418                                struct strbuf *msg = NULL;
4419                                msg = options->output_prefix(options,
4420                                        options->output_prefix_data);
4421                                fwrite(msg->buf, msg->len, 1, stdout);
4422                        }
4423                        putc(options->line_termination, options->file);
4424                        if (options->stat_sep) {
4425                                /* attach patch instead of inline */
4426                                fputs(options->stat_sep, options->file);
4427                        }
4428                }
4429
4430                for (i = 0; i < q->nr; i++) {
4431                        struct diff_filepair *p = q->queue[i];
4432                        if (check_pair_status(p))
4433                                diff_flush_patch(p, options);
4434                }
4435        }
4436
4437        if (output_format & DIFF_FORMAT_CALLBACK)
4438                options->format_callback(q, options, options->format_callback_data);
4439
4440        for (i = 0; i < q->nr; i++)
4441                diff_free_filepair(q->queue[i]);
4442free_queue:
4443        free(q->queue);
4444        DIFF_QUEUE_CLEAR(q);
4445        if (options->close_file)
4446                fclose(options->file);
4447
4448        /*
4449         * Report the content-level differences with HAS_CHANGES;
4450         * diff_addremove/diff_change does not set the bit when
4451         * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4452         */
4453        if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4454                if (options->found_changes)
4455                        DIFF_OPT_SET(options, HAS_CHANGES);
4456                else
4457                        DIFF_OPT_CLR(options, HAS_CHANGES);
4458        }
4459}
4460
4461static void diffcore_apply_filter(const char *filter)
4462{
4463        int i;
4464        struct diff_queue_struct *q = &diff_queued_diff;
4465        struct diff_queue_struct outq;
4466        DIFF_QUEUE_CLEAR(&outq);
4467
4468        if (!filter)
4469                return;
4470
4471        if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
4472                int found;
4473                for (i = found = 0; !found && i < q->nr; i++) {
4474                        struct diff_filepair *p = q->queue[i];
4475                        if (((p->status == DIFF_STATUS_MODIFIED) &&
4476                             ((p->score &&
4477                               strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4478                              (!p->score &&
4479                               strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4480                            ((p->status != DIFF_STATUS_MODIFIED) &&
4481                             strchr(filter, p->status)))
4482                                found++;
4483                }
4484                if (found)
4485                        return;
4486
4487                /* otherwise we will clear the whole queue
4488                 * by copying the empty outq at the end of this
4489                 * function, but first clear the current entries
4490                 * in the queue.
4491                 */
4492                for (i = 0; i < q->nr; i++)
4493                        diff_free_filepair(q->queue[i]);
4494        }
4495        else {
4496                /* Only the matching ones */
4497                for (i = 0; i < q->nr; i++) {
4498                        struct diff_filepair *p = q->queue[i];
4499
4500                        if (((p->status == DIFF_STATUS_MODIFIED) &&
4501                             ((p->score &&
4502                               strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
4503                              (!p->score &&
4504                               strchr(filter, DIFF_STATUS_MODIFIED)))) ||
4505                            ((p->status != DIFF_STATUS_MODIFIED) &&
4506                             strchr(filter, p->status)))
4507                                diff_q(&outq, p);
4508                        else
4509                                diff_free_filepair(p);
4510                }
4511        }
4512        free(q->queue);
4513        *q = outq;
4514}
4515
4516/* Check whether two filespecs with the same mode and size are identical */
4517static int diff_filespec_is_identical(struct diff_filespec *one,
4518                                      struct diff_filespec *two)
4519{
4520        if (S_ISGITLINK(one->mode))
4521                return 0;
4522        if (diff_populate_filespec(one, 0))
4523                return 0;
4524        if (diff_populate_filespec(two, 0))
4525                return 0;
4526        return !memcmp(one->data, two->data, one->size);
4527}
4528
4529static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4530{
4531        int i;
4532        struct diff_queue_struct *q = &diff_queued_diff;
4533        struct diff_queue_struct outq;
4534        DIFF_QUEUE_CLEAR(&outq);
4535
4536        for (i = 0; i < q->nr; i++) {
4537                struct diff_filepair *p = q->queue[i];
4538
4539                /*
4540                 * 1. Entries that come from stat info dirtiness
4541                 *    always have both sides (iow, not create/delete),
4542                 *    one side of the object name is unknown, with
4543                 *    the same mode and size.  Keep the ones that
4544                 *    do not match these criteria.  They have real
4545                 *    differences.
4546                 *
4547                 * 2. At this point, the file is known to be modified,
4548                 *    with the same mode and size, and the object
4549                 *    name of one side is unknown.  Need to inspect
4550                 *    the identical contents.
4551                 */
4552                if (!DIFF_FILE_VALID(p->one) || /* (1) */
4553                    !DIFF_FILE_VALID(p->two) ||
4554                    (p->one->sha1_valid && p->two->sha1_valid) ||
4555                    (p->one->mode != p->two->mode) ||
4556                    diff_populate_filespec(p->one, 1) ||
4557                    diff_populate_filespec(p->two, 1) ||
4558                    (p->one->size != p->two->size) ||
4559                    !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4560                        diff_q(&outq, p);
4561                else {
4562                        /*
4563                         * The caller can subtract 1 from skip_stat_unmatch
4564                         * to determine how many paths were dirty only
4565                         * due to stat info mismatch.
4566                         */
4567                        if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4568                                diffopt->skip_stat_unmatch++;
4569                        diff_free_filepair(p);
4570                }
4571        }
4572        free(q->queue);
4573        *q = outq;
4574}
4575
4576static int diffnamecmp(const void *a_, const void *b_)
4577{
4578        const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4579        const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4580        const char *name_a, *name_b;
4581
4582        name_a = a->one ? a->one->path : a->two->path;
4583        name_b = b->one ? b->one->path : b->two->path;
4584        return strcmp(name_a, name_b);
4585}
4586
4587void diffcore_fix_diff_index(struct diff_options *options)
4588{
4589        struct diff_queue_struct *q = &diff_queued_diff;
4590        qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4591}
4592
4593void diffcore_std(struct diff_options *options)
4594{
4595        if (options->skip_stat_unmatch)
4596                diffcore_skip_stat_unmatch(options);
4597        if (!options->found_follow) {
4598                /* See try_to_follow_renames() in tree-diff.c */
4599                if (options->break_opt != -1)
4600                        diffcore_break(options->break_opt);
4601                if (options->detect_rename)
4602                        diffcore_rename(options);
4603                if (options->break_opt != -1)
4604                        diffcore_merge_broken();
4605        }
4606        if (options->pickaxe)
4607                diffcore_pickaxe(options);
4608        if (options->orderfile)
4609                diffcore_order(options->orderfile);
4610        if (!options->found_follow)
4611                /* See try_to_follow_renames() in tree-diff.c */
4612                diff_resolve_rename_copy();
4613        diffcore_apply_filter(options->filter);
4614
4615        if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4616                DIFF_OPT_SET(options, HAS_CHANGES);
4617        else
4618                DIFF_OPT_CLR(options, HAS_CHANGES);
4619
4620        options->found_follow = 0;
4621}
4622
4623int diff_result_code(struct diff_options *opt, int status)
4624{
4625        int result = 0;
4626
4627        diff_warn_rename_limit("diff.renamelimit",
4628                               opt->needed_rename_limit,
4629                               opt->degraded_cc_to_c);
4630        if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4631            !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4632                return status;
4633        if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4634            DIFF_OPT_TST(opt, HAS_CHANGES))
4635                result |= 01;
4636        if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4637            DIFF_OPT_TST(opt, CHECK_FAILED))
4638                result |= 02;
4639        return result;
4640}
4641
4642int diff_can_quit_early(struct diff_options *opt)
4643{
4644        return (DIFF_OPT_TST(opt, QUICK) &&
4645                !opt->filter &&
4646                DIFF_OPT_TST(opt, HAS_CHANGES));
4647}
4648
4649/*
4650 * Shall changes to this submodule be ignored?
4651 *
4652 * Submodule changes can be configured to be ignored separately for each path,
4653 * but that configuration can be overridden from the command line.
4654 */
4655static int is_submodule_ignored(const char *path, struct diff_options *options)
4656{
4657        int ignored = 0;
4658        unsigned orig_flags = options->flags;
4659        if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4660                set_diffopt_flags_from_submodule_config(options, path);
4661        if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4662                ignored = 1;
4663        options->flags = orig_flags;
4664        return ignored;
4665}
4666
4667void diff_addremove(struct diff_options *options,
4668                    int addremove, unsigned mode,
4669                    const unsigned char *sha1,
4670                    const char *concatpath, unsigned dirty_submodule)
4671{
4672        struct diff_filespec *one, *two;
4673
4674        if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4675                return;
4676
4677        /* This may look odd, but it is a preparation for
4678         * feeding "there are unchanged files which should
4679         * not produce diffs, but when you are doing copy
4680         * detection you would need them, so here they are"
4681         * entries to the diff-core.  They will be prefixed
4682         * with something like '=' or '*' (I haven't decided
4683         * which but should not make any difference).
4684         * Feeding the same new and old to diff_change()
4685         * also has the same effect.
4686         * Before the final output happens, they are pruned after
4687         * merged into rename/copy pairs as appropriate.
4688         */
4689        if (DIFF_OPT_TST(options, REVERSE_DIFF))
4690                addremove = (addremove == '+' ? '-' :
4691                             addremove == '-' ? '+' : addremove);
4692
4693        if (options->prefix &&
4694            strncmp(concatpath, options->prefix, options->prefix_length))
4695                return;
4696
4697        one = alloc_filespec(concatpath);
4698        two = alloc_filespec(concatpath);
4699
4700        if (addremove != '+')
4701                fill_filespec(one, sha1, mode);
4702        if (addremove != '-') {
4703                fill_filespec(two, sha1, mode);
4704                two->dirty_submodule = dirty_submodule;
4705        }
4706
4707        diff_queue(&diff_queued_diff, one, two);
4708        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4709                DIFF_OPT_SET(options, HAS_CHANGES);
4710}
4711
4712void diff_change(struct diff_options *options,
4713                 unsigned old_mode, unsigned new_mode,
4714                 const unsigned char *old_sha1,
4715                 const unsigned char *new_sha1,
4716                 const char *concatpath,
4717                 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4718{
4719        struct diff_filespec *one, *two;
4720
4721        if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4722            is_submodule_ignored(concatpath, options))
4723                return;
4724
4725        if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
4726                unsigned tmp;
4727                const unsigned char *tmp_c;
4728                tmp = old_mode; old_mode = new_mode; new_mode = tmp;
4729                tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
4730                tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
4731                        new_dirty_submodule = tmp;
4732        }
4733
4734        if (options->prefix &&
4735            strncmp(concatpath, options->prefix, options->prefix_length))
4736                return;
4737
4738        one = alloc_filespec(concatpath);
4739        two = alloc_filespec(concatpath);
4740        fill_filespec(one, old_sha1, old_mode);
4741        fill_filespec(two, new_sha1, new_mode);
4742        one->dirty_submodule = old_dirty_submodule;
4743        two->dirty_submodule = new_dirty_submodule;
4744
4745        diff_queue(&diff_queued_diff, one, two);
4746        if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4747                DIFF_OPT_SET(options, HAS_CHANGES);
4748}
4749
4750struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
4751{
4752        struct diff_filepair *pair;
4753        struct diff_filespec *one, *two;
4754
4755        if (options->prefix &&
4756            strncmp(path, options->prefix, options->prefix_length))
4757                return NULL;
4758
4759        one = alloc_filespec(path);
4760        two = alloc_filespec(path);
4761        pair = diff_queue(&diff_queued_diff, one, two);
4762        pair->is_unmerged = 1;
4763        return pair;
4764}
4765
4766static char *run_textconv(const char *pgm, struct diff_filespec *spec,
4767                size_t *outsize)
4768{
4769        struct diff_tempfile *temp;
4770        const char *argv[3];
4771        const char **arg = argv;
4772        struct child_process child;
4773        struct strbuf buf = STRBUF_INIT;
4774        int err = 0;
4775
4776        temp = prepare_temp_file(spec->path, spec);
4777        *arg++ = pgm;
4778        *arg++ = temp->name;
4779        *arg = NULL;
4780
4781        memset(&child, 0, sizeof(child));
4782        child.use_shell = 1;
4783        child.argv = argv;
4784        child.out = -1;
4785        if (start_command(&child)) {
4786                remove_tempfile();
4787                return NULL;
4788        }
4789
4790        if (strbuf_read(&buf, child.out, 0) < 0)
4791                err = error("error reading from textconv command '%s'", pgm);
4792        close(child.out);
4793
4794        if (finish_command(&child) || err) {
4795                strbuf_release(&buf);
4796                remove_tempfile();
4797                return NULL;
4798        }
4799        remove_tempfile();
4800
4801        return strbuf_detach(&buf, outsize);
4802}
4803
4804size_t fill_textconv(struct userdiff_driver *driver,
4805                     struct diff_filespec *df,
4806                     char **outbuf)
4807{
4808        size_t size;
4809
4810        if (!driver || !driver->textconv) {
4811                if (!DIFF_FILE_VALID(df)) {
4812                        *outbuf = "";
4813                        return 0;
4814                }
4815                if (diff_populate_filespec(df, 0))
4816                        die("unable to read files to diff");
4817                *outbuf = df->data;
4818                return df->size;
4819        }
4820
4821        if (driver->textconv_cache && df->sha1_valid) {
4822                *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
4823                                          &size);
4824                if (*outbuf)
4825                        return size;
4826        }
4827
4828        *outbuf = run_textconv(driver->textconv, df, &size);
4829        if (!*outbuf)
4830                die("unable to read files to diff");
4831
4832        if (driver->textconv_cache && df->sha1_valid) {
4833                /* ignore errors, as we might be in a readonly repository */
4834                notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
4835                                size);
4836                /*
4837                 * we could save up changes and flush them all at the end,
4838                 * but we would need an extra call after all diffing is done.
4839                 * Since generating a cache entry is the slow path anyway,
4840                 * this extra overhead probably isn't a big deal.
4841                 */
4842                notes_cache_write(driver->textconv_cache);
4843        }
4844
4845        return size;
4846}