git.oblomov.eu Git - git/blob - diff.c

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