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

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4 #include <sys/types.h>
   5 #include <sys/wait.h>
   6 #include <signal.h>
   7 #include "cache.h"
   8 #include "quote.h"
   9 #include "diff.h"
  10 #include "diffcore.h"
  11 #include "delta.h"
  12 #include "xdiff-interface.h"
  13
  14 static int use_size_cache;
  15
  16 static int diff_rename_limit_default = -1;
  17 static int diff_use_color_default = 0;
  18
  19 enum color_diff {
  20         DIFF_RESET = 0,
  21         DIFF_PLAIN = 1,
  22         DIFF_METAINFO = 2,
  23         DIFF_FRAGINFO = 3,
  24         DIFF_FILE_OLD = 4,
  25         DIFF_FILE_NEW = 5,
  26 };
  27
  28 #define COLOR_NORMAL  ""
  29 #define COLOR_BOLD    "\033[1m"
  30 #define COLOR_DIM     "\033[2m"
  31 #define COLOR_UL      "\033[4m"
  32 #define COLOR_BLINK   "\033[5m"
  33 #define COLOR_REVERSE "\033[7m"
  34 #define COLOR_RESET   "\033[m"
  35
  36 #define COLOR_BLACK   "\033[30m"
  37 #define COLOR_RED     "\033[31m"
  38 #define COLOR_GREEN   "\033[32m"
  39 #define COLOR_YELLOW  "\033[33m"
  40 #define COLOR_BLUE    "\033[34m"
  41 #define COLOR_MAGENTA "\033[35m"
  42 #define COLOR_CYAN    "\033[36m"
  43 #define COLOR_WHITE   "\033[37m"
  44
  45 static const char *diff_colors[] = {
  46         [DIFF_RESET]    = COLOR_RESET,
  47         [DIFF_PLAIN]    = COLOR_NORMAL,
  48         [DIFF_METAINFO] = COLOR_BOLD,
  49         [DIFF_FRAGINFO] = COLOR_CYAN,
  50         [DIFF_FILE_OLD] = COLOR_RED,
  51         [DIFF_FILE_NEW] = COLOR_GREEN,
  52 };
  53
  54 static int parse_diff_color_slot(const char *var, int ofs)
  55 {
  56         if (!strcasecmp(var+ofs, "plain"))
  57                 return DIFF_PLAIN;
  58         if (!strcasecmp(var+ofs, "meta"))
  59                 return DIFF_METAINFO;
  60         if (!strcasecmp(var+ofs, "frag"))
  61                 return DIFF_FRAGINFO;
  62         if (!strcasecmp(var+ofs, "old"))
  63                 return DIFF_FILE_OLD;
  64         if (!strcasecmp(var+ofs, "new"))
  65                 return DIFF_FILE_NEW;
  66         die("bad config variable '%s'", var);
  67 }
  68
  69 static const char *parse_diff_color_value(const char *value, const char *var)
  70 {
  71         if (!strcasecmp(value, "normal"))
  72                 return COLOR_NORMAL;
  73         if (!strcasecmp(value, "bold"))
  74                 return COLOR_BOLD;
  75         if (!strcasecmp(value, "dim"))
  76                 return COLOR_DIM;
  77         if (!strcasecmp(value, "ul"))
  78                 return COLOR_UL;
  79         if (!strcasecmp(value, "blink"))
  80                 return COLOR_BLINK;
  81         if (!strcasecmp(value, "reverse"))
  82                 return COLOR_REVERSE;
  83         if (!strcasecmp(value, "reset"))
  84                 return COLOR_RESET;
  85         if (!strcasecmp(value, "black"))
  86                 return COLOR_BLACK;
  87         if (!strcasecmp(value, "red"))
  88                 return COLOR_RED;
  89         if (!strcasecmp(value, "green"))
  90                 return COLOR_GREEN;
  91         if (!strcasecmp(value, "yellow"))
  92                 return COLOR_YELLOW;
  93         if (!strcasecmp(value, "blue"))
  94                 return COLOR_BLUE;
  95         if (!strcasecmp(value, "magenta"))
  96                 return COLOR_MAGENTA;
  97         if (!strcasecmp(value, "cyan"))
  98                 return COLOR_CYAN;
  99         if (!strcasecmp(value, "white"))
 100                 return COLOR_WHITE;
 101         die("bad config value '%s' for variable '%s'", value, var);
 102 }
 103
 104 int git_diff_config(const char *var, const char *value)
 105 {
 106         if (!strcmp(var, "diff.renamelimit")) {
 107                 diff_rename_limit_default = git_config_int(var, value);
 108                 return 0;
 109         }
 110         if (!strcmp(var, "diff.color")) {
 111                 if (!value)
 112                         diff_use_color_default = 1; /* bool */
 113                 else if (!strcasecmp(value, "auto")) {
 114                         diff_use_color_default = 0;
 115                         if (isatty(1)) {
 116                                 char *term = getenv("TERM");
 117                                 if (term && strcmp(term, "dumb"))
 118                                         diff_use_color_default = 1;
 119                         }
 120                 }
 121                 else if (!strcasecmp(value, "never"))
 122                         diff_use_color_default = 0;
 123                 else if (!strcasecmp(value, "always"))
 124                         diff_use_color_default = 1;
 125                 else
 126                         diff_use_color_default = git_config_bool(var, value);
 127                 return 0;
 128         }
 129         if (!strncmp(var, "diff.color.", 11)) {
 130                 int slot = parse_diff_color_slot(var, 11);
 131                 diff_colors[slot] = parse_diff_color_value(value, var);
 132                 return 0;
 133         }
 134         return git_default_config(var, value);
 135 }
 136
 137 static char *quote_one(const char *str)
 138 {
 139         int needlen;
 140         char *xp;
 141
 142         if (!str)
 143                 return NULL;
 144         needlen = quote_c_style(str, NULL, NULL, 0);
 145         if (!needlen)
 146                 return strdup(str);
 147         xp = xmalloc(needlen + 1);
 148         quote_c_style(str, xp, NULL, 0);
 149         return xp;
 150 }
 151
 152 static char *quote_two(const char *one, const char *two)
 153 {
 154         int need_one = quote_c_style(one, NULL, NULL, 1);
 155         int need_two = quote_c_style(two, NULL, NULL, 1);
 156         char *xp;
 157
 158         if (need_one + need_two) {
 159                 if (!need_one) need_one = strlen(one);
 160                 if (!need_two) need_one = strlen(two);
 161
 162                 xp = xmalloc(need_one + need_two + 3);
 163                 xp[0] = '"';
 164                 quote_c_style(one, xp + 1, NULL, 1);
 165                 quote_c_style(two, xp + need_one + 1, NULL, 1);
 166                 strcpy(xp + need_one + need_two + 1, "\"");
 167                 return xp;
 168         }
 169         need_one = strlen(one);
 170         need_two = strlen(two);
 171         xp = xmalloc(need_one + need_two + 1);
 172         strcpy(xp, one);
 173         strcpy(xp + need_one, two);
 174         return xp;
 175 }
 176
 177 static const char *external_diff(void)
 178 {
 179         static const char *external_diff_cmd = NULL;
 180         static int done_preparing = 0;
 181
 182         if (done_preparing)
 183                 return external_diff_cmd;
 184         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 185         done_preparing = 1;
 186         return external_diff_cmd;
 187 }
 188
 189 #define TEMPFILE_PATH_LEN               50
 190
 191 static struct diff_tempfile {
 192         const char *name; /* filename external diff should read from */
 193         char hex[41];
 194         char mode[10];
 195         char tmp_path[TEMPFILE_PATH_LEN];
 196 } diff_temp[2];
 197
 198 static int count_lines(const char *data, int size)
 199 {
 200         int count, ch, completely_empty = 1, nl_just_seen = 0;
 201         count = 0;
 202         while (0 < size--) {
 203                 ch = *data++;
 204                 if (ch == '\n') {
 205                         count++;
 206                         nl_just_seen = 1;
 207                         completely_empty = 0;
 208                 }
 209                 else {
 210                         nl_just_seen = 0;
 211                         completely_empty = 0;
 212                 }
 213         }
 214         if (completely_empty)
 215                 return 0;
 216         if (!nl_just_seen)
 217                 count++; /* no trailing newline */
 218         return count;
 219 }
 220
 221 static void print_line_count(int count)
 222 {
 223         switch (count) {
 224         case 0:
 225                 printf("0,0");
 226                 break;
 227         case 1:
 228                 printf("1");
 229                 break;
 230         default:
 231                 printf("1,%d", count);
 232                 break;
 233         }
 234 }
 235
 236 static void copy_file(int prefix, const char *data, int size)
 237 {
 238         int ch, nl_just_seen = 1;
 239         while (0 < size--) {
 240                 ch = *data++;
 241                 if (nl_just_seen)
 242                         putchar(prefix);
 243                 putchar(ch);
 244                 if (ch == '\n')
 245                         nl_just_seen = 1;
 246                 else
 247                         nl_just_seen = 0;
 248         }
 249         if (!nl_just_seen)
 250                 printf("\n\\ No newline at end of file\n");
 251 }
 252
 253 static void emit_rewrite_diff(const char *name_a,
 254                               const char *name_b,
 255                               struct diff_filespec *one,
 256                               struct diff_filespec *two)
 257 {
 258         int lc_a, lc_b;
 259         diff_populate_filespec(one, 0);
 260         diff_populate_filespec(two, 0);
 261         lc_a = count_lines(one->data, one->size);
 262         lc_b = count_lines(two->data, two->size);
 263         printf("--- %s\n+++ %s\n@@ -", name_a, name_b);
 264         print_line_count(lc_a);
 265         printf(" +");
 266         print_line_count(lc_b);
 267         printf(" @@\n");
 268         if (lc_a)
 269                 copy_file('-', one->data, one->size);
 270         if (lc_b)
 271                 copy_file('+', two->data, two->size);
 272 }
 273
 274 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 275 {
 276         if (!DIFF_FILE_VALID(one)) {
 277                 mf->ptr = (char *)""; /* does not matter */
 278                 mf->size = 0;
 279                 return 0;
 280         }
 281         else if (diff_populate_filespec(one, 0))
 282                 return -1;
 283         mf->ptr = one->data;
 284         mf->size = one->size;
 285         return 0;
 286 }
 287
 288 struct emit_callback {
 289         struct xdiff_emit_state xm;
 290         int nparents, color_diff;
 291         const char **label_path;
 292 };
 293
 294 static inline const char *get_color(int diff_use_color, enum color_diff ix)
 295 {
 296         if (diff_use_color)
 297                 return diff_colors[ix];
 298         return "";
 299 }
 300
 301 static void fn_out_consume(void *priv, char *line, unsigned long len)
 302 {
 303         int i;
 304         struct emit_callback *ecbdata = priv;
 305         const char *set = get_color(ecbdata->color_diff, DIFF_METAINFO);
 306         const char *reset = get_color(ecbdata->color_diff, DIFF_RESET);
 307
 308         if (ecbdata->label_path[0]) {
 309                 printf("%s--- %s%s\n", set, ecbdata->label_path[0], reset);
 310                 printf("%s+++ %s%s\n", set, ecbdata->label_path[1], reset);
 311                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
 312         }
 313
 314         /* This is not really necessary for now because
 315          * this codepath only deals with two-way diffs.
 316          */
 317         for (i = 0; i < len && line[i] == '@'; i++)
 318                 ;
 319         if (2 <= i && i < len && line[i] == ' ') {
 320                 ecbdata->nparents = i - 1;
 321                 set = get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 322         }
 323         else if (len < ecbdata->nparents)
 324                 set = reset;
 325         else {
 326                 int nparents = ecbdata->nparents;
 327                 int color = DIFF_PLAIN;
 328                 for (i = 0; i < nparents && len; i++) {
 329                         if (line[i] == '-')
 330                                 color = DIFF_FILE_OLD;
 331                         else if (line[i] == '+')
 332                                 color = DIFF_FILE_NEW;
 333                 }
 334                 set = get_color(ecbdata->color_diff, color);
 335         }
 336         if (len > 0 && line[len-1] == '\n')
 337                 len--;
 338         fputs (set, stdout);
 339         fwrite (line, len, 1, stdout);
 340         puts (reset);
 341 }
 342
 343 static char *pprint_rename(const char *a, const char *b)
 344 {
 345         const char *old = a;
 346         const char *new = b;
 347         char *name = NULL;
 348         int pfx_length, sfx_length;
 349         int len_a = strlen(a);
 350         int len_b = strlen(b);
 351
 352         /* Find common prefix */
 353         pfx_length = 0;
 354         while (*old && *new && *old == *new) {
 355                 if (*old == '/')
 356                         pfx_length = old - a + 1;
 357                 old++;
 358                 new++;
 359         }
 360
 361         /* Find common suffix */
 362         old = a + len_a;
 363         new = b + len_b;
 364         sfx_length = 0;
 365         while (a <= old && b <= new && *old == *new) {
 366                 if (*old == '/')
 367                         sfx_length = len_a - (old - a);
 368                 old--;
 369                 new--;
 370         }
 371
 372         /*
 373          * pfx{mid-a => mid-b}sfx
 374          * {pfx-a => pfx-b}sfx
 375          * pfx{sfx-a => sfx-b}
 376          * name-a => name-b
 377          */
 378         if (pfx_length + sfx_length) {
 379                 int a_midlen = len_a - pfx_length - sfx_length;
 380                 int b_midlen = len_b - pfx_length - sfx_length;
 381                 if (a_midlen < 0) a_midlen = 0;
 382                 if (b_midlen < 0) b_midlen = 0;
 383
 384                 name = xmalloc(pfx_length + a_midlen + b_midlen + sfx_length + 7);
 385                 sprintf(name, "%.*s{%.*s => %.*s}%s",
 386                         pfx_length, a,
 387                         a_midlen, a + pfx_length,
 388                         b_midlen, b + pfx_length,
 389                         a + len_a - sfx_length);
 390         }
 391         else {
 392                 name = xmalloc(len_a + len_b + 5);
 393                 sprintf(name, "%s => %s", a, b);
 394         }
 395         return name;
 396 }
 397
 398 struct diffstat_t {
 399         struct xdiff_emit_state xm;
 400
 401         int nr;
 402         int alloc;
 403         struct diffstat_file {
 404                 char *name;
 405                 unsigned is_unmerged:1;
 406                 unsigned is_binary:1;
 407                 unsigned is_renamed:1;
 408                 unsigned int added, deleted;
 409         } **files;
 410 };
 411
 412 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
 413                                           const char *name_a,
 414                                           const char *name_b)
 415 {
 416         struct diffstat_file *x;
 417         x = xcalloc(sizeof (*x), 1);
 418         if (diffstat->nr == diffstat->alloc) {
 419                 diffstat->alloc = alloc_nr(diffstat->alloc);
 420                 diffstat->files = xrealloc(diffstat->files,
 421                                 diffstat->alloc * sizeof(x));
 422         }
 423         diffstat->files[diffstat->nr++] = x;
 424         if (name_b) {
 425                 x->name = pprint_rename(name_a, name_b);
 426                 x->is_renamed = 1;
 427         }
 428         else
 429                 x->name = strdup(name_a);
 430         return x;
 431 }
 432
 433 static void diffstat_consume(void *priv, char *line, unsigned long len)
 434 {
 435         struct diffstat_t *diffstat = priv;
 436         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
 437
 438         if (line[0] == '+')
 439                 x->added++;
 440         else if (line[0] == '-')
 441                 x->deleted++;
 442 }
 443
 444 static const char pluses[] = "++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++";
 445 static const char minuses[]= "----------------------------------------------------------------------";
 446 const char mime_boundary_leader[] = "------------";
 447
 448 static void show_stats(struct diffstat_t* data)
 449 {
 450         int i, len, add, del, total, adds = 0, dels = 0;
 451         int max, max_change = 0, max_len = 0;
 452         int total_files = data->nr;
 453
 454         if (data->nr == 0)
 455                 return;
 456
 457         for (i = 0; i < data->nr; i++) {
 458                 struct diffstat_file *file = data->files[i];
 459
 460                 len = strlen(file->name);
 461                 if (max_len < len)
 462                         max_len = len;
 463
 464                 if (file->is_binary || file->is_unmerged)
 465                         continue;
 466                 if (max_change < file->added + file->deleted)
 467                         max_change = file->added + file->deleted;
 468         }
 469
 470         for (i = 0; i < data->nr; i++) {
 471                 const char *prefix = "";
 472                 char *name = data->files[i]->name;
 473                 int added = data->files[i]->added;
 474                 int deleted = data->files[i]->deleted;
 475
 476                 if (0 < (len = quote_c_style(name, NULL, NULL, 0))) {
 477                         char *qname = xmalloc(len + 1);
 478                         quote_c_style(name, qname, NULL, 0);
 479                         free(name);
 480                         data->files[i]->name = name = qname;
 481                 }
 482
 483                 /*
 484                  * "scale" the filename
 485                  */
 486                 len = strlen(name);
 487                 max = max_len;
 488                 if (max > 50)
 489                         max = 50;
 490                 if (len > max) {
 491                         char *slash;
 492                         prefix = "...";
 493                         max -= 3;
 494                         name += len - max;
 495                         slash = strchr(name, '/');
 496                         if (slash)
 497                                 name = slash;
 498                 }
 499                 len = max;
 500
 501                 /*
 502                  * scale the add/delete
 503                  */
 504                 max = max_change;
 505                 if (max + len > 70)
 506                         max = 70 - len;
 507
 508                 if (data->files[i]->is_binary) {
 509                         printf(" %s%-*s |  Bin\n", prefix, len, name);
 510                         goto free_diffstat_file;
 511                 }
 512                 else if (data->files[i]->is_unmerged) {
 513                         printf(" %s%-*s |  Unmerged\n", prefix, len, name);
 514                         goto free_diffstat_file;
 515                 }
 516                 else if (!data->files[i]->is_renamed &&
 517                          (added + deleted == 0)) {
 518                         total_files--;
 519                         goto free_diffstat_file;
 520                 }
 521
 522                 add = added;
 523                 del = deleted;
 524                 total = add + del;
 525                 adds += add;
 526                 dels += del;
 527
 528                 if (max_change > 0) {
 529                         total = (total * max + max_change / 2) / max_change;
 530                         add = (add * max + max_change / 2) / max_change;
 531                         del = total - add;
 532                 }
 533                 printf(" %s%-*s |%5d %.*s%.*s\n", prefix,
 534                                 len, name, added + deleted,
 535                                 add, pluses, del, minuses);
 536         free_diffstat_file:
 537                 free(data->files[i]->name);
 538                 free(data->files[i]);
 539         }
 540         free(data->files);
 541         printf(" %d files changed, %d insertions(+), %d deletions(-)\n",
 542                         total_files, adds, dels);
 543 }
 544
 545 struct checkdiff_t {
 546         struct xdiff_emit_state xm;
 547         const char *filename;
 548         int lineno;
 549 };
 550
 551 static void checkdiff_consume(void *priv, char *line, unsigned long len)
 552 {
 553         struct checkdiff_t *data = priv;
 554
 555         if (line[0] == '+') {
 556                 int i, spaces = 0;
 557
 558                 data->lineno++;
 559
 560                 /* check space before tab */
 561                 for (i = 1; i < len && (line[i] == ' ' || line[i] == '\t'); i++)
 562                         if (line[i] == ' ')
 563                                 spaces++;
 564                 if (line[i - 1] == '\t' && spaces)
 565                         printf("%s:%d: space before tab:%.*s\n",
 566                                 data->filename, data->lineno, (int)len, line);
 567
 568                 /* check white space at line end */
 569                 if (line[len - 1] == '\n')
 570                         len--;
 571                 if (isspace(line[len - 1]))
 572                         printf("%s:%d: white space at end: %.*s\n",
 573                                 data->filename, data->lineno, (int)len, line);
 574         } else if (line[0] == ' ')
 575                 data->lineno++;
 576         else if (line[0] == '@') {
 577                 char *plus = strchr(line, '+');
 578                 if (plus)
 579                         data->lineno = strtol(plus, NULL, 10);
 580                 else
 581                         die("invalid diff");
 582         }
 583 }
 584
 585 static unsigned char *deflate_it(char *data,
 586                                  unsigned long size,
 587                                  unsigned long *result_size)
 588 {
 589         int bound;
 590         unsigned char *deflated;
 591         z_stream stream;
 592
 593         memset(&stream, 0, sizeof(stream));
 594         deflateInit(&stream, zlib_compression_level);
 595         bound = deflateBound(&stream, size);
 596         deflated = xmalloc(bound);
 597         stream.next_out = deflated;
 598         stream.avail_out = bound;
 599
 600         stream.next_in = (unsigned char *)data;
 601         stream.avail_in = size;
 602         while (deflate(&stream, Z_FINISH) == Z_OK)
 603                 ; /* nothing */
 604         deflateEnd(&stream);
 605         *result_size = stream.total_out;
 606         return deflated;
 607 }
 608
 609 static void emit_binary_diff(mmfile_t *one, mmfile_t *two)
 610 {
 611         void *cp;
 612         void *delta;
 613         void *deflated;
 614         void *data;
 615         unsigned long orig_size;
 616         unsigned long delta_size;
 617         unsigned long deflate_size;
 618         unsigned long data_size;
 619
 620         printf("GIT binary patch\n");
 621         /* We could do deflated delta, or we could do just deflated two,
 622          * whichever is smaller.
 623          */
 624         delta = NULL;
 625         deflated = deflate_it(two->ptr, two->size, &deflate_size);
 626         if (one->size && two->size) {
 627                 delta = diff_delta(one->ptr, one->size,
 628                                    two->ptr, two->size,
 629                                    &delta_size, deflate_size);
 630                 if (delta) {
 631                         void *to_free = delta;
 632                         orig_size = delta_size;
 633                         delta = deflate_it(delta, delta_size, &delta_size);
 634                         free(to_free);
 635                 }
 636         }
 637
 638         if (delta && delta_size < deflate_size) {
 639                 printf("delta %lu\n", orig_size);
 640                 free(deflated);
 641                 data = delta;
 642                 data_size = delta_size;
 643         }
 644         else {
 645                 printf("literal %lu\n", two->size);
 646                 free(delta);
 647                 data = deflated;
 648                 data_size = deflate_size;
 649         }
 650
 651         /* emit data encoded in base85 */
 652         cp = data;
 653         while (data_size) {
 654                 int bytes = (52 < data_size) ? 52 : data_size;
 655                 char line[70];
 656                 data_size -= bytes;
 657                 if (bytes <= 26)
 658                         line[0] = bytes + 'A' - 1;
 659                 else
 660                         line[0] = bytes - 26 + 'a' - 1;
 661                 encode_85(line + 1, cp, bytes);
 662                 cp = (char *) cp + bytes;
 663                 puts(line);
 664         }
 665         printf("\n");
 666         free(data);
 667 }
 668
 669 #define FIRST_FEW_BYTES 8000
 670 static int mmfile_is_binary(mmfile_t *mf)
 671 {
 672         long sz = mf->size;
 673         if (FIRST_FEW_BYTES < sz)
 674                 sz = FIRST_FEW_BYTES;
 675         if (memchr(mf->ptr, 0, sz))
 676                 return 1;
 677         return 0;
 678 }
 679
 680 static void builtin_diff(const char *name_a,
 681                          const char *name_b,
 682                          struct diff_filespec *one,
 683                          struct diff_filespec *two,
 684                          const char *xfrm_msg,
 685                          struct diff_options *o,
 686                          int complete_rewrite)
 687 {
 688         mmfile_t mf1, mf2;
 689         const char *lbl[2];
 690         char *a_one, *b_two;
 691         const char *set = get_color(o->color_diff, DIFF_METAINFO);
 692         const char *reset = get_color(o->color_diff, DIFF_RESET);
 693
 694         a_one = quote_two("a/", name_a);
 695         b_two = quote_two("b/", name_b);
 696         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
 697         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
 698         printf("%sdiff --git %s %s%s\n", set, a_one, b_two, reset);
 699         if (lbl[0][0] == '/') {
 700                 /* /dev/null */
 701                 printf("%snew file mode %06o%s\n", set, two->mode, reset);
 702                 if (xfrm_msg && xfrm_msg[0])
 703                         printf("%s%s%s\n", set, xfrm_msg, reset);
 704         }
 705         else if (lbl[1][0] == '/') {
 706                 printf("%sdeleted file mode %06o%s\n", set, one->mode, reset);
 707                 if (xfrm_msg && xfrm_msg[0])
 708                         printf("%s%s%s\n", set, xfrm_msg, reset);
 709         }
 710         else {
 711                 if (one->mode != two->mode) {
 712                         printf("%sold mode %06o%s\n", set, one->mode, reset);
 713                         printf("%snew mode %06o%s\n", set, two->mode, reset);
 714                 }
 715                 if (xfrm_msg && xfrm_msg[0])
 716                         printf("%s%s%s\n", set, xfrm_msg, reset);
 717                 /*
 718                  * we do not run diff between different kind
 719                  * of objects.
 720                  */
 721                 if ((one->mode ^ two->mode) & S_IFMT)
 722                         goto free_ab_and_return;
 723                 if (complete_rewrite) {
 724                         emit_rewrite_diff(name_a, name_b, one, two);
 725                         goto free_ab_and_return;
 726                 }
 727         }
 728
 729         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
 730                 die("unable to read files to diff");
 731
 732         if (mmfile_is_binary(&mf1) || mmfile_is_binary(&mf2)) {
 733                 /* Quite common confusing case */
 734                 if (mf1.size == mf2.size &&
 735                     !memcmp(mf1.ptr, mf2.ptr, mf1.size))
 736                         goto free_ab_and_return;
 737                 if (o->binary)
 738                         emit_binary_diff(&mf1, &mf2);
 739                 else
 740                         printf("Binary files %s and %s differ\n",
 741                                lbl[0], lbl[1]);
 742         }
 743         else {
 744                 /* Crazy xdl interfaces.. */
 745                 const char *diffopts = getenv("GIT_DIFF_OPTS");
 746                 xpparam_t xpp;
 747                 xdemitconf_t xecfg;
 748                 xdemitcb_t ecb;
 749                 struct emit_callback ecbdata;
 750
 751                 memset(&ecbdata, 0, sizeof(ecbdata));
 752                 ecbdata.label_path = lbl;
 753                 ecbdata.color_diff = o->color_diff;
 754                 xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
 755                 xecfg.ctxlen = o->context;
 756                 xecfg.flags = XDL_EMIT_FUNCNAMES;
 757                 if (!diffopts)
 758                         ;
 759                 else if (!strncmp(diffopts, "--unified=", 10))
 760                         xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
 761                 else if (!strncmp(diffopts, "-u", 2))
 762                         xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
 763                 ecb.outf = xdiff_outf;
 764                 ecb.priv = &ecbdata;
 765                 ecbdata.xm.consume = fn_out_consume;
 766                 xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
 767         }
 768
 769  free_ab_and_return:
 770         free(a_one);
 771         free(b_two);
 772         return;
 773 }
 774
 775 static void builtin_diffstat(const char *name_a, const char *name_b,
 776                              struct diff_filespec *one,
 777                              struct diff_filespec *two,
 778                              struct diffstat_t *diffstat,
 779                              struct diff_options *o,
 780                              int complete_rewrite)
 781 {
 782         mmfile_t mf1, mf2;
 783         struct diffstat_file *data;
 784
 785         data = diffstat_add(diffstat, name_a, name_b);
 786
 787         if (!one || !two) {
 788                 data->is_unmerged = 1;
 789                 return;
 790         }
 791         if (complete_rewrite) {
 792                 diff_populate_filespec(one, 0);
 793                 diff_populate_filespec(two, 0);
 794                 data->deleted = count_lines(one->data, one->size);
 795                 data->added = count_lines(two->data, two->size);
 796                 return;
 797         }
 798         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
 799                 die("unable to read files to diff");
 800
 801         if (mmfile_is_binary(&mf1) || mmfile_is_binary(&mf2))
 802                 data->is_binary = 1;
 803         else {
 804                 /* Crazy xdl interfaces.. */
 805                 xpparam_t xpp;
 806                 xdemitconf_t xecfg;
 807                 xdemitcb_t ecb;
 808
 809                 xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
 810                 xecfg.ctxlen = 0;
 811                 xecfg.flags = 0;
 812                 ecb.outf = xdiff_outf;
 813                 ecb.priv = diffstat;
 814                 xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
 815         }
 816 }
 817
 818 static void builtin_checkdiff(const char *name_a, const char *name_b,
 819                              struct diff_filespec *one,
 820                              struct diff_filespec *two)
 821 {
 822         mmfile_t mf1, mf2;
 823         struct checkdiff_t data;
 824
 825         if (!two)
 826                 return;
 827
 828         memset(&data, 0, sizeof(data));
 829         data.xm.consume = checkdiff_consume;
 830         data.filename = name_b ? name_b : name_a;
 831         data.lineno = 0;
 832
 833         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
 834                 die("unable to read files to diff");
 835
 836         if (mmfile_is_binary(&mf2))
 837                 return;
 838         else {
 839                 /* Crazy xdl interfaces.. */
 840                 xpparam_t xpp;
 841                 xdemitconf_t xecfg;
 842                 xdemitcb_t ecb;
 843
 844                 xpp.flags = XDF_NEED_MINIMAL;
 845                 xecfg.ctxlen = 0;
 846                 xecfg.flags = 0;
 847                 ecb.outf = xdiff_outf;
 848                 ecb.priv = &data;
 849                 xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
 850         }
 851 }
 852
 853 struct diff_filespec *alloc_filespec(const char *path)
 854 {
 855         int namelen = strlen(path);
 856         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
 857
 858         memset(spec, 0, sizeof(*spec));
 859         spec->path = (char *)(spec + 1);
 860         memcpy(spec->path, path, namelen+1);
 861         return spec;
 862 }
 863
 864 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
 865                    unsigned short mode)
 866 {
 867         if (mode) {
 868                 spec->mode = canon_mode(mode);
 869                 memcpy(spec->sha1, sha1, 20);
 870                 spec->sha1_valid = !!memcmp(sha1, null_sha1, 20);
 871         }
 872 }
 873
 874 /*
 875  * Given a name and sha1 pair, if the dircache tells us the file in
 876  * the work tree has that object contents, return true, so that
 877  * prepare_temp_file() does not have to inflate and extract.
 878  */
 879 static int work_tree_matches(const char *name, const unsigned char *sha1)
 880 {
 881         struct cache_entry *ce;
 882         struct stat st;
 883         int pos, len;
 884
 885         /* We do not read the cache ourselves here, because the
 886          * benchmark with my previous version that always reads cache
 887          * shows that it makes things worse for diff-tree comparing
 888          * two linux-2.6 kernel trees in an already checked out work
 889          * tree.  This is because most diff-tree comparisons deal with
 890          * only a small number of files, while reading the cache is
 891          * expensive for a large project, and its cost outweighs the
 892          * savings we get by not inflating the object to a temporary
 893          * file.  Practically, this code only helps when we are used
 894          * by diff-cache --cached, which does read the cache before
 895          * calling us.
 896          */
 897         if (!active_cache)
 898                 return 0;
 899
 900         len = strlen(name);
 901         pos = cache_name_pos(name, len);
 902         if (pos < 0)
 903                 return 0;
 904         ce = active_cache[pos];
 905         if ((lstat(name, &st) < 0) ||
 906             !S_ISREG(st.st_mode) || /* careful! */
 907             ce_match_stat(ce, &st, 0) ||
 908             memcmp(sha1, ce->sha1, 20))
 909                 return 0;
 910         /* we return 1 only when we can stat, it is a regular file,
 911          * stat information matches, and sha1 recorded in the cache
 912          * matches.  I.e. we know the file in the work tree really is
 913          * the same as the <name, sha1> pair.
 914          */
 915         return 1;
 916 }
 917
 918 static struct sha1_size_cache {
 919         unsigned char sha1[20];
 920         unsigned long size;
 921 } **sha1_size_cache;
 922 static int sha1_size_cache_nr, sha1_size_cache_alloc;
 923
 924 static struct sha1_size_cache *locate_size_cache(unsigned char *sha1,
 925                                                  int find_only,
 926                                                  unsigned long size)
 927 {
 928         int first, last;
 929         struct sha1_size_cache *e;
 930
 931         first = 0;
 932         last = sha1_size_cache_nr;
 933         while (last > first) {
 934                 int cmp, next = (last + first) >> 1;
 935                 e = sha1_size_cache[next];
 936                 cmp = memcmp(e->sha1, sha1, 20);
 937                 if (!cmp)
 938                         return e;
 939                 if (cmp < 0) {
 940                         last = next;
 941                         continue;
 942                 }
 943                 first = next+1;
 944         }
 945         /* not found */
 946         if (find_only)
 947                 return NULL;
 948         /* insert to make it at "first" */
 949         if (sha1_size_cache_alloc <= sha1_size_cache_nr) {
 950                 sha1_size_cache_alloc = alloc_nr(sha1_size_cache_alloc);
 951                 sha1_size_cache = xrealloc(sha1_size_cache,
 952                                            sha1_size_cache_alloc *
 953                                            sizeof(*sha1_size_cache));
 954         }
 955         sha1_size_cache_nr++;
 956         if (first < sha1_size_cache_nr)
 957                 memmove(sha1_size_cache + first + 1, sha1_size_cache + first,
 958                         (sha1_size_cache_nr - first - 1) *
 959                         sizeof(*sha1_size_cache));
 960         e = xmalloc(sizeof(struct sha1_size_cache));
 961         sha1_size_cache[first] = e;
 962         memcpy(e->sha1, sha1, 20);
 963         e->size = size;
 964         return e;
 965 }
 966
 967 /*
 968  * While doing rename detection and pickaxe operation, we may need to
 969  * grab the data for the blob (or file) for our own in-core comparison.
 970  * diff_filespec has data and size fields for this purpose.
 971  */
 972 int diff_populate_filespec(struct diff_filespec *s, int size_only)
 973 {
 974         int err = 0;
 975         if (!DIFF_FILE_VALID(s))
 976                 die("internal error: asking to populate invalid file.");
 977         if (S_ISDIR(s->mode))
 978                 return -1;
 979
 980         if (!use_size_cache)
 981                 size_only = 0;
 982
 983         if (s->data)
 984                 return err;
 985         if (!s->sha1_valid ||
 986             work_tree_matches(s->path, s->sha1)) {
 987                 struct stat st;
 988                 int fd;
 989                 if (lstat(s->path, &st) < 0) {
 990                         if (errno == ENOENT) {
 991                         err_empty:
 992                                 err = -1;
 993                         empty:
 994                                 s->data = (char *)"";
 995                                 s->size = 0;
 996                                 return err;
 997                         }
 998                 }
 999                 s->size = st.st_size;
1000                 if (!s->size)
1001                         goto empty;
1002                 if (size_only)
1003                         return 0;
1004                 if (S_ISLNK(st.st_mode)) {
1005                         int ret;
1006                         s->data = xmalloc(s->size);
1007                         s->should_free = 1;
1008                         ret = readlink(s->path, s->data, s->size);
1009                         if (ret < 0) {
1010                                 free(s->data);
1011                                 goto err_empty;
1012                         }
1013                         return 0;
1014                 }
1015                 fd = open(s->path, O_RDONLY);
1016                 if (fd < 0)
1017                         goto err_empty;
1018                 s->data = mmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
1019                 close(fd);
1020                 if (s->data == MAP_FAILED)
1021                         goto err_empty;
1022                 s->should_munmap = 1;
1023         }
1024         else {
1025                 char type[20];
1026                 struct sha1_size_cache *e;
1027
1028                 if (size_only) {
1029                         e = locate_size_cache(s->sha1, 1, 0);
1030                         if (e) {
1031                                 s->size = e->size;
1032                                 return 0;
1033                         }
1034                         if (!sha1_object_info(s->sha1, type, &s->size))
1035                                 locate_size_cache(s->sha1, 0, s->size);
1036                 }
1037                 else {
1038                         s->data = read_sha1_file(s->sha1, type, &s->size);
1039                         s->should_free = 1;
1040                 }
1041         }
1042         return 0;
1043 }
1044
1045 void diff_free_filespec_data(struct diff_filespec *s)
1046 {
1047         if (s->should_free)
1048                 free(s->data);
1049         else if (s->should_munmap)
1050                 munmap(s->data, s->size);
1051         s->should_free = s->should_munmap = 0;
1052         s->data = NULL;
1053         free(s->cnt_data);
1054         s->cnt_data = NULL;
1055 }
1056
1057 static void prep_temp_blob(struct diff_tempfile *temp,
1058                            void *blob,
1059                            unsigned long size,
1060                            const unsigned char *sha1,
1061                            int mode)
1062 {
1063         int fd;
1064
1065         fd = git_mkstemp(temp->tmp_path, TEMPFILE_PATH_LEN, ".diff_XXXXXX");
1066         if (fd < 0)
1067                 die("unable to create temp-file");
1068         if (write(fd, blob, size) != size)
1069                 die("unable to write temp-file");
1070         close(fd);
1071         temp->name = temp->tmp_path;
1072         strcpy(temp->hex, sha1_to_hex(sha1));
1073         temp->hex[40] = 0;
1074         sprintf(temp->mode, "%06o", mode);
1075 }
1076
1077 static void prepare_temp_file(const char *name,
1078                               struct diff_tempfile *temp,
1079                               struct diff_filespec *one)
1080 {
1081         if (!DIFF_FILE_VALID(one)) {
1082         not_a_valid_file:
1083                 /* A '-' entry produces this for file-2, and
1084                  * a '+' entry produces this for file-1.
1085                  */
1086                 temp->name = "/dev/null";
1087                 strcpy(temp->hex, ".");
1088                 strcpy(temp->mode, ".");
1089                 return;
1090         }
1091
1092         if (!one->sha1_valid ||
1093             work_tree_matches(name, one->sha1)) {
1094                 struct stat st;
1095                 if (lstat(name, &st) < 0) {
1096                         if (errno == ENOENT)
1097                                 goto not_a_valid_file;
1098                         die("stat(%s): %s", name, strerror(errno));
1099                 }
1100                 if (S_ISLNK(st.st_mode)) {
1101                         int ret;
1102                         char buf[PATH_MAX + 1]; /* ought to be SYMLINK_MAX */
1103                         if (sizeof(buf) <= st.st_size)
1104                                 die("symlink too long: %s", name);
1105                         ret = readlink(name, buf, st.st_size);
1106                         if (ret < 0)
1107                                 die("readlink(%s)", name);
1108                         prep_temp_blob(temp, buf, st.st_size,
1109                                        (one->sha1_valid ?
1110                                         one->sha1 : null_sha1),
1111                                        (one->sha1_valid ?
1112                                         one->mode : S_IFLNK));
1113                 }
1114                 else {
1115                         /* we can borrow from the file in the work tree */
1116                         temp->name = name;
1117                         if (!one->sha1_valid)
1118                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
1119                         else
1120                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
1121                         /* Even though we may sometimes borrow the
1122                          * contents from the work tree, we always want
1123                          * one->mode.  mode is trustworthy even when
1124                          * !(one->sha1_valid), as long as
1125                          * DIFF_FILE_VALID(one).
1126                          */
1127                         sprintf(temp->mode, "%06o", one->mode);
1128                 }
1129                 return;
1130         }
1131         else {
1132                 if (diff_populate_filespec(one, 0))
1133                         die("cannot read data blob for %s", one->path);
1134                 prep_temp_blob(temp, one->data, one->size,
1135                                one->sha1, one->mode);
1136         }
1137 }
1138
1139 static void remove_tempfile(void)
1140 {
1141         int i;
1142
1143         for (i = 0; i < 2; i++)
1144                 if (diff_temp[i].name == diff_temp[i].tmp_path) {
1145                         unlink(diff_temp[i].name);
1146                         diff_temp[i].name = NULL;
1147                 }
1148 }
1149
1150 static void remove_tempfile_on_signal(int signo)
1151 {
1152         remove_tempfile();
1153         signal(SIGINT, SIG_DFL);
1154         raise(signo);
1155 }
1156
1157 static int spawn_prog(const char *pgm, const char **arg)
1158 {
1159         pid_t pid;
1160         int status;
1161
1162         fflush(NULL);
1163         pid = fork();
1164         if (pid < 0)
1165                 die("unable to fork");
1166         if (!pid) {
1167                 execvp(pgm, (char *const*) arg);
1168                 exit(255);
1169         }
1170
1171         while (waitpid(pid, &status, 0) < 0) {
1172                 if (errno == EINTR)
1173                         continue;
1174                 return -1;
1175         }
1176
1177         /* Earlier we did not check the exit status because
1178          * diff exits non-zero if files are different, and
1179          * we are not interested in knowing that.  It was a
1180          * mistake which made it harder to quit a diff-*
1181          * session that uses the git-apply-patch-script as
1182          * the GIT_EXTERNAL_DIFF.  A custom GIT_EXTERNAL_DIFF
1183          * should also exit non-zero only when it wants to
1184          * abort the entire diff-* session.
1185          */
1186         if (WIFEXITED(status) && !WEXITSTATUS(status))
1187                 return 0;
1188         return -1;
1189 }
1190
1191 /* An external diff command takes:
1192  *
1193  * diff-cmd name infile1 infile1-sha1 infile1-mode \
1194  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
1195  *
1196  */
1197 static void run_external_diff(const char *pgm,
1198                               const char *name,
1199                               const char *other,
1200                               struct diff_filespec *one,
1201                               struct diff_filespec *two,
1202                               const char *xfrm_msg,
1203                               int complete_rewrite)
1204 {
1205         const char *spawn_arg[10];
1206         struct diff_tempfile *temp = diff_temp;
1207         int retval;
1208         static int atexit_asked = 0;
1209         const char *othername;
1210         const char **arg = &spawn_arg[0];
1211
1212         othername = (other? other : name);
1213         if (one && two) {
1214                 prepare_temp_file(name, &temp[0], one);
1215                 prepare_temp_file(othername, &temp[1], two);
1216                 if (! atexit_asked &&
1217                     (temp[0].name == temp[0].tmp_path ||
1218                      temp[1].name == temp[1].tmp_path)) {
1219                         atexit_asked = 1;
1220                         atexit(remove_tempfile);
1221                 }
1222                 signal(SIGINT, remove_tempfile_on_signal);
1223         }
1224
1225         if (one && two) {
1226                 *arg++ = pgm;
1227                 *arg++ = name;
1228                 *arg++ = temp[0].name;
1229                 *arg++ = temp[0].hex;
1230                 *arg++ = temp[0].mode;
1231                 *arg++ = temp[1].name;
1232                 *arg++ = temp[1].hex;
1233                 *arg++ = temp[1].mode;
1234                 if (other) {
1235                         *arg++ = other;
1236                         *arg++ = xfrm_msg;
1237                 }
1238         } else {
1239                 *arg++ = pgm;
1240                 *arg++ = name;
1241         }
1242         *arg = NULL;
1243         retval = spawn_prog(pgm, spawn_arg);
1244         remove_tempfile();
1245         if (retval) {
1246                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
1247                 exit(1);
1248         }
1249 }
1250
1251 static void run_diff_cmd(const char *pgm,
1252                          const char *name,
1253                          const char *other,
1254                          struct diff_filespec *one,
1255                          struct diff_filespec *two,
1256                          const char *xfrm_msg,
1257                          struct diff_options *o,
1258                          int complete_rewrite)
1259 {
1260         if (pgm) {
1261                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
1262                                   complete_rewrite);
1263                 return;
1264         }
1265         if (one && two)
1266                 builtin_diff(name, other ? other : name,
1267                              one, two, xfrm_msg, o, complete_rewrite);
1268         else
1269                 printf("* Unmerged path %s\n", name);
1270 }
1271
1272 static void diff_fill_sha1_info(struct diff_filespec *one)
1273 {
1274         if (DIFF_FILE_VALID(one)) {
1275                 if (!one->sha1_valid) {
1276                         struct stat st;
1277                         if (lstat(one->path, &st) < 0)
1278                                 die("stat %s", one->path);
1279                         if (index_path(one->sha1, one->path, &st, 0))
1280                                 die("cannot hash %s\n", one->path);
1281                 }
1282         }
1283         else
1284                 memset(one->sha1, 0, 20);
1285 }
1286
1287 static void run_diff(struct diff_filepair *p, struct diff_options *o)
1288 {
1289         const char *pgm = external_diff();
1290         char msg[PATH_MAX*2+300], *xfrm_msg;
1291         struct diff_filespec *one;
1292         struct diff_filespec *two;
1293         const char *name;
1294         const char *other;
1295         char *name_munged, *other_munged;
1296         int complete_rewrite = 0;
1297         int len;
1298
1299         if (DIFF_PAIR_UNMERGED(p)) {
1300                 /* unmerged */
1301                 run_diff_cmd(pgm, p->one->path, NULL, NULL, NULL, NULL, o, 0);
1302                 return;
1303         }
1304
1305         name = p->one->path;
1306         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
1307         name_munged = quote_one(name);
1308         other_munged = quote_one(other);
1309         one = p->one; two = p->two;
1310
1311         diff_fill_sha1_info(one);
1312         diff_fill_sha1_info(two);
1313
1314         len = 0;
1315         switch (p->status) {
1316         case DIFF_STATUS_COPIED:
1317                 len += snprintf(msg + len, sizeof(msg) - len,
1318                                 "similarity index %d%%\n"
1319                                 "copy from %s\n"
1320                                 "copy to %s\n",
1321                                 (int)(0.5 + p->score * 100.0/MAX_SCORE),
1322                                 name_munged, other_munged);
1323                 break;
1324         case DIFF_STATUS_RENAMED:
1325                 len += snprintf(msg + len, sizeof(msg) - len,
1326                                 "similarity index %d%%\n"
1327                                 "rename from %s\n"
1328                                 "rename to %s\n",
1329                                 (int)(0.5 + p->score * 100.0/MAX_SCORE),
1330                                 name_munged, other_munged);
1331                 break;
1332         case DIFF_STATUS_MODIFIED:
1333                 if (p->score) {
1334                         len += snprintf(msg + len, sizeof(msg) - len,
1335                                         "dissimilarity index %d%%\n",
1336                                         (int)(0.5 + p->score *
1337                                               100.0/MAX_SCORE));
1338                         complete_rewrite = 1;
1339                         break;
1340                 }
1341                 /* fallthru */
1342         default:
1343                 /* nothing */
1344                 ;
1345         }
1346
1347         if (memcmp(one->sha1, two->sha1, 20)) {
1348                 int abbrev = o->full_index ? 40 : DEFAULT_ABBREV;
1349
1350                 len += snprintf(msg + len, sizeof(msg) - len,
1351                                 "index %.*s..%.*s",
1352                                 abbrev, sha1_to_hex(one->sha1),
1353                                 abbrev, sha1_to_hex(two->sha1));
1354                 if (one->mode == two->mode)
1355                         len += snprintf(msg + len, sizeof(msg) - len,
1356                                         " %06o", one->mode);
1357                 len += snprintf(msg + len, sizeof(msg) - len, "\n");
1358         }
1359
1360         if (len)
1361                 msg[--len] = 0;
1362         xfrm_msg = len ? msg : NULL;
1363
1364         if (!pgm &&
1365             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
1366             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
1367                 /* a filepair that changes between file and symlink
1368                  * needs to be split into deletion and creation.
1369                  */
1370                 struct diff_filespec *null = alloc_filespec(two->path);
1371                 run_diff_cmd(NULL, name, other, one, null, xfrm_msg, o, 0);
1372                 free(null);
1373                 null = alloc_filespec(one->path);
1374                 run_diff_cmd(NULL, name, other, null, two, xfrm_msg, o, 0);
1375                 free(null);
1376         }
1377         else
1378                 run_diff_cmd(pgm, name, other, one, two, xfrm_msg, o,
1379                              complete_rewrite);
1380
1381         free(name_munged);
1382         free(other_munged);
1383 }
1384
1385 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
1386                          struct diffstat_t *diffstat)
1387 {
1388         const char *name;
1389         const char *other;
1390         int complete_rewrite = 0;
1391
1392         if (DIFF_PAIR_UNMERGED(p)) {
1393                 /* unmerged */
1394                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, 0);
1395                 return;
1396         }
1397
1398         name = p->one->path;
1399         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
1400
1401         diff_fill_sha1_info(p->one);
1402         diff_fill_sha1_info(p->two);
1403
1404         if (p->status == DIFF_STATUS_MODIFIED && p->score)
1405                 complete_rewrite = 1;
1406         builtin_diffstat(name, other, p->one, p->two, diffstat, o, complete_rewrite);
1407 }
1408
1409 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
1410 {
1411         const char *name;
1412         const char *other;
1413
1414         if (DIFF_PAIR_UNMERGED(p)) {
1415                 /* unmerged */
1416                 return;
1417         }
1418
1419         name = p->one->path;
1420         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
1421
1422         diff_fill_sha1_info(p->one);
1423         diff_fill_sha1_info(p->two);
1424
1425         builtin_checkdiff(name, other, p->one, p->two);
1426 }
1427
1428 void diff_setup(struct diff_options *options)
1429 {
1430         memset(options, 0, sizeof(*options));
1431         options->line_termination = '\n';
1432         options->break_opt = -1;
1433         options->rename_limit = -1;
1434         options->context = 3;
1435         options->msg_sep = "";
1436
1437         options->change = diff_change;
1438         options->add_remove = diff_addremove;
1439         options->color_diff = diff_use_color_default;
1440 }
1441
1442 int diff_setup_done(struct diff_options *options)
1443 {
1444         if ((options->find_copies_harder &&
1445              options->detect_rename != DIFF_DETECT_COPY) ||
1446             (0 <= options->rename_limit && !options->detect_rename))
1447                 return -1;
1448
1449         if (options->output_format & (DIFF_FORMAT_NAME |
1450                                       DIFF_FORMAT_NAME_STATUS |
1451                                       DIFF_FORMAT_CHECKDIFF |
1452                                       DIFF_FORMAT_NO_OUTPUT))
1453                 options->output_format &= ~(DIFF_FORMAT_RAW |
1454                                             DIFF_FORMAT_DIFFSTAT |
1455                                             DIFF_FORMAT_SUMMARY |
1456                                             DIFF_FORMAT_PATCH);
1457
1458         /*
1459          * These cases always need recursive; we do not drop caller-supplied
1460          * recursive bits for other formats here.
1461          */
1462         if (options->output_format & (DIFF_FORMAT_PATCH |
1463                                       DIFF_FORMAT_DIFFSTAT |
1464                                       DIFF_FORMAT_CHECKDIFF))
1465                 options->recursive = 1;
1466         /*
1467          * Also pickaxe would not work very well if you do not say recursive
1468          */
1469         if (options->pickaxe)
1470                 options->recursive = 1;
1471
1472         if (options->detect_rename && options->rename_limit < 0)
1473                 options->rename_limit = diff_rename_limit_default;
1474         if (options->setup & DIFF_SETUP_USE_CACHE) {
1475                 if (!active_cache)
1476                         /* read-cache does not die even when it fails
1477                          * so it is safe for us to do this here.  Also
1478                          * it does not smudge active_cache or active_nr
1479                          * when it fails, so we do not have to worry about
1480                          * cleaning it up ourselves either.
1481                          */
1482                         read_cache();
1483         }
1484         if (options->setup & DIFF_SETUP_USE_SIZE_CACHE)
1485                 use_size_cache = 1;
1486         if (options->abbrev <= 0 || 40 < options->abbrev)
1487                 options->abbrev = 40; /* full */
1488
1489         return 0;
1490 }
1491
1492 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
1493 {
1494         char c, *eq;
1495         int len;
1496
1497         if (*arg != '-')
1498                 return 0;
1499         c = *++arg;
1500         if (!c)
1501                 return 0;
1502         if (c == arg_short) {
1503                 c = *++arg;
1504                 if (!c)
1505                         return 1;
1506                 if (val && isdigit(c)) {
1507                         char *end;
1508                         int n = strtoul(arg, &end, 10);
1509                         if (*end)
1510                                 return 0;
1511                         *val = n;
1512                         return 1;
1513                 }
1514                 return 0;
1515         }
1516         if (c != '-')
1517                 return 0;
1518         arg++;
1519         eq = strchr(arg, '=');
1520         if (eq)
1521                 len = eq - arg;
1522         else
1523                 len = strlen(arg);
1524         if (!len || strncmp(arg, arg_long, len))
1525                 return 0;
1526         if (eq) {
1527                 int n;
1528                 char *end;
1529                 if (!isdigit(*++eq))
1530                         return 0;
1531                 n = strtoul(eq, &end, 10);
1532                 if (*end)
1533                         return 0;
1534                 *val = n;
1535         }
1536         return 1;
1537 }
1538
1539 int diff_opt_parse(struct diff_options *options, const char **av, int ac)
1540 {
1541         const char *arg = av[0];
1542         if (!strcmp(arg, "-p") || !strcmp(arg, "-u"))
1543                 options->output_format |= DIFF_FORMAT_PATCH;
1544         else if (opt_arg(arg, 'U', "unified", &options->context))
1545                 options->output_format |= DIFF_FORMAT_PATCH;
1546         else if (!strcmp(arg, "--raw"))
1547                 options->output_format |= DIFF_FORMAT_RAW;
1548         else if (!strcmp(arg, "--patch-with-raw")) {
1549                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
1550         }
1551         else if (!strcmp(arg, "--stat"))
1552                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
1553         else if (!strcmp(arg, "--check"))
1554                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
1555         else if (!strcmp(arg, "--summary"))
1556                 options->output_format |= DIFF_FORMAT_SUMMARY;
1557         else if (!strcmp(arg, "--patch-with-stat")) {
1558                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
1559         }
1560         else if (!strcmp(arg, "-z"))
1561                 options->line_termination = 0;
1562         else if (!strncmp(arg, "-l", 2))
1563                 options->rename_limit = strtoul(arg+2, NULL, 10);
1564         else if (!strcmp(arg, "--full-index"))
1565                 options->full_index = 1;
1566         else if (!strcmp(arg, "--binary")) {
1567                 options->output_format |= DIFF_FORMAT_PATCH;
1568                 options->full_index = options->binary = 1;
1569         }
1570         else if (!strcmp(arg, "--name-only"))
1571                 options->output_format |= DIFF_FORMAT_NAME;
1572         else if (!strcmp(arg, "--name-status"))
1573                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
1574         else if (!strcmp(arg, "-R"))
1575                 options->reverse_diff = 1;
1576         else if (!strncmp(arg, "-S", 2))
1577                 options->pickaxe = arg + 2;
1578         else if (!strcmp(arg, "-s")) {
1579                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
1580         }
1581         else if (!strncmp(arg, "-O", 2))
1582                 options->orderfile = arg + 2;
1583         else if (!strncmp(arg, "--diff-filter=", 14))
1584                 options->filter = arg + 14;
1585         else if (!strcmp(arg, "--pickaxe-all"))
1586                 options->pickaxe_opts = DIFF_PICKAXE_ALL;
1587         else if (!strcmp(arg, "--pickaxe-regex"))
1588                 options->pickaxe_opts = DIFF_PICKAXE_REGEX;
1589         else if (!strncmp(arg, "-B", 2)) {
1590                 if ((options->break_opt =
1591                      diff_scoreopt_parse(arg)) == -1)
1592                         return -1;
1593         }
1594         else if (!strncmp(arg, "-M", 2)) {
1595                 if ((options->rename_score =
1596                      diff_scoreopt_parse(arg)) == -1)
1597                         return -1;
1598                 options->detect_rename = DIFF_DETECT_RENAME;
1599         }
1600         else if (!strncmp(arg, "-C", 2)) {
1601                 if ((options->rename_score =
1602                      diff_scoreopt_parse(arg)) == -1)
1603                         return -1;
1604                 options->detect_rename = DIFF_DETECT_COPY;
1605         }
1606         else if (!strcmp(arg, "--find-copies-harder"))
1607                 options->find_copies_harder = 1;
1608         else if (!strcmp(arg, "--abbrev"))
1609                 options->abbrev = DEFAULT_ABBREV;
1610         else if (!strncmp(arg, "--abbrev=", 9)) {
1611                 options->abbrev = strtoul(arg + 9, NULL, 10);
1612                 if (options->abbrev < MINIMUM_ABBREV)
1613                         options->abbrev = MINIMUM_ABBREV;
1614                 else if (40 < options->abbrev)
1615                         options->abbrev = 40;
1616         }
1617         else if (!strcmp(arg, "--color"))
1618                 options->color_diff = 1;
1619         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
1620                 options->xdl_opts |= XDF_IGNORE_WHITESPACE;
1621         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
1622                 options->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
1623         else
1624                 return 0;
1625         return 1;
1626 }
1627
1628 static int parse_num(const char **cp_p)
1629 {
1630         unsigned long num, scale;
1631         int ch, dot;
1632         const char *cp = *cp_p;
1633
1634         num = 0;
1635         scale = 1;
1636         dot = 0;
1637         for(;;) {
1638                 ch = *cp;
1639                 if ( !dot && ch == '.' ) {
1640                         scale = 1;
1641                         dot = 1;
1642                 } else if ( ch == '%' ) {
1643                         scale = dot ? scale*100 : 100;
1644                         cp++;   /* % is always at the end */
1645                         break;
1646                 } else if ( ch >= '0' && ch <= '9' ) {
1647                         if ( scale < 100000 ) {
1648                                 scale *= 10;
1649                                 num = (num*10) + (ch-'0');
1650                         }
1651                 } else {
1652                         break;
1653                 }
1654                 cp++;
1655         }
1656         *cp_p = cp;
1657
1658         /* user says num divided by scale and we say internally that
1659          * is MAX_SCORE * num / scale.
1660          */
1661         return (num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale);
1662 }
1663
1664 int diff_scoreopt_parse(const char *opt)
1665 {
1666         int opt1, opt2, cmd;
1667
1668         if (*opt++ != '-')
1669                 return -1;
1670         cmd = *opt++;
1671         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
1672                 return -1; /* that is not a -M, -C nor -B option */
1673
1674         opt1 = parse_num(&opt);
1675         if (cmd != 'B')
1676                 opt2 = 0;
1677         else {
1678                 if (*opt == 0)
1679                         opt2 = 0;
1680                 else if (*opt != '/')
1681                         return -1; /* we expect -B80/99 or -B80 */
1682                 else {
1683                         opt++;
1684                         opt2 = parse_num(&opt);
1685                 }
1686         }
1687         if (*opt != 0)
1688                 return -1;
1689         return opt1 | (opt2 << 16);
1690 }
1691
1692 struct diff_queue_struct diff_queued_diff;
1693
1694 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
1695 {
1696         if (queue->alloc <= queue->nr) {
1697                 queue->alloc = alloc_nr(queue->alloc);
1698                 queue->queue = xrealloc(queue->queue,
1699                                         sizeof(dp) * queue->alloc);
1700         }
1701         queue->queue[queue->nr++] = dp;
1702 }
1703
1704 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
1705                                  struct diff_filespec *one,
1706                                  struct diff_filespec *two)
1707 {
1708         struct diff_filepair *dp = xmalloc(sizeof(*dp));
1709         dp->one = one;
1710         dp->two = two;
1711         dp->score = 0;
1712         dp->status = 0;
1713         dp->source_stays = 0;
1714         dp->broken_pair = 0;
1715         if (queue)
1716                 diff_q(queue, dp);
1717         return dp;
1718 }
1719
1720 void diff_free_filepair(struct diff_filepair *p)
1721 {
1722         diff_free_filespec_data(p->one);
1723         diff_free_filespec_data(p->two);
1724         free(p->one);
1725         free(p->two);
1726         free(p);
1727 }
1728
1729 /* This is different from find_unique_abbrev() in that
1730  * it stuffs the result with dots for alignment.
1731  */
1732 const char *diff_unique_abbrev(const unsigned char *sha1, int len)
1733 {
1734         int abblen;
1735         const char *abbrev;
1736         if (len == 40)
1737                 return sha1_to_hex(sha1);
1738
1739         abbrev = find_unique_abbrev(sha1, len);
1740         if (!abbrev)
1741                 return sha1_to_hex(sha1);
1742         abblen = strlen(abbrev);
1743         if (abblen < 37) {
1744                 static char hex[41];
1745                 if (len < abblen && abblen <= len + 2)
1746                         sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
1747                 else
1748                         sprintf(hex, "%s...", abbrev);
1749                 return hex;
1750         }
1751         return sha1_to_hex(sha1);
1752 }
1753
1754 static void diff_flush_raw(struct diff_filepair *p,
1755                            struct diff_options *options)
1756 {
1757         int two_paths;
1758         char status[10];
1759         int abbrev = options->abbrev;
1760         const char *path_one, *path_two;
1761         int inter_name_termination = '\t';
1762         int line_termination = options->line_termination;
1763
1764         if (!line_termination)
1765                 inter_name_termination = 0;
1766
1767         path_one = p->one->path;
1768         path_two = p->two->path;
1769         if (line_termination) {
1770                 path_one = quote_one(path_one);
1771                 path_two = quote_one(path_two);
1772         }
1773
1774         if (p->score)
1775                 sprintf(status, "%c%03d", p->status,
1776                         (int)(0.5 + p->score * 100.0/MAX_SCORE));
1777         else {
1778                 status[0] = p->status;
1779                 status[1] = 0;
1780         }
1781         switch (p->status) {
1782         case DIFF_STATUS_COPIED:
1783         case DIFF_STATUS_RENAMED:
1784                 two_paths = 1;
1785                 break;
1786         case DIFF_STATUS_ADDED:
1787         case DIFF_STATUS_DELETED:
1788                 two_paths = 0;
1789                 break;
1790         default:
1791                 two_paths = 0;
1792                 break;
1793         }
1794         if (!(options->output_format & DIFF_FORMAT_NAME_STATUS)) {
1795                 printf(":%06o %06o %s ",
1796                        p->one->mode, p->two->mode,
1797                        diff_unique_abbrev(p->one->sha1, abbrev));
1798                 printf("%s ",
1799                        diff_unique_abbrev(p->two->sha1, abbrev));
1800         }
1801         printf("%s%c%s", status, inter_name_termination, path_one);
1802         if (two_paths)
1803                 printf("%c%s", inter_name_termination, path_two);
1804         putchar(line_termination);
1805         if (path_one != p->one->path)
1806                 free((void*)path_one);
1807         if (path_two != p->two->path)
1808                 free((void*)path_two);
1809 }
1810
1811 static void diff_flush_name(struct diff_filepair *p, int line_termination)
1812 {
1813         char *path = p->two->path;
1814
1815         if (line_termination)
1816                 path = quote_one(p->two->path);
1817         printf("%s%c", path, line_termination);
1818         if (p->two->path != path)
1819                 free(path);
1820 }
1821
1822 int diff_unmodified_pair(struct diff_filepair *p)
1823 {
1824         /* This function is written stricter than necessary to support
1825          * the currently implemented transformers, but the idea is to
1826          * let transformers to produce diff_filepairs any way they want,
1827          * and filter and clean them up here before producing the output.
1828          */
1829         struct diff_filespec *one, *two;
1830
1831         if (DIFF_PAIR_UNMERGED(p))
1832                 return 0; /* unmerged is interesting */
1833
1834         one = p->one;
1835         two = p->two;
1836
1837         /* deletion, addition, mode or type change
1838          * and rename are all interesting.
1839          */
1840         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
1841             DIFF_PAIR_MODE_CHANGED(p) ||
1842             strcmp(one->path, two->path))
1843                 return 0;
1844
1845         /* both are valid and point at the same path.  that is, we are
1846          * dealing with a change.
1847          */
1848         if (one->sha1_valid && two->sha1_valid &&
1849             !memcmp(one->sha1, two->sha1, sizeof(one->sha1)))
1850                 return 1; /* no change */
1851         if (!one->sha1_valid && !two->sha1_valid)
1852                 return 1; /* both look at the same file on the filesystem. */
1853         return 0;
1854 }
1855
1856 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
1857 {
1858         if (diff_unmodified_pair(p))
1859                 return;
1860
1861         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
1862             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
1863                 return; /* no tree diffs in patch format */
1864
1865         run_diff(p, o);
1866 }
1867
1868 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
1869                             struct diffstat_t *diffstat)
1870 {
1871         if (diff_unmodified_pair(p))
1872                 return;
1873
1874         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
1875             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
1876                 return; /* no tree diffs in patch format */
1877
1878         run_diffstat(p, o, diffstat);
1879 }
1880
1881 static void diff_flush_checkdiff(struct diff_filepair *p,
1882                 struct diff_options *o)
1883 {
1884         if (diff_unmodified_pair(p))
1885                 return;
1886
1887         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
1888             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
1889                 return; /* no tree diffs in patch format */
1890
1891         run_checkdiff(p, o);
1892 }
1893
1894 int diff_queue_is_empty(void)
1895 {
1896         struct diff_queue_struct *q = &diff_queued_diff;
1897         int i;
1898         for (i = 0; i < q->nr; i++)
1899                 if (!diff_unmodified_pair(q->queue[i]))
1900                         return 0;
1901         return 1;
1902 }
1903
1904 #if DIFF_DEBUG
1905 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
1906 {
1907         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
1908                 x, one ? one : "",
1909                 s->path,
1910                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
1911                 s->mode,
1912                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
1913         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
1914                 x, one ? one : "",
1915                 s->size, s->xfrm_flags);
1916 }
1917
1918 void diff_debug_filepair(const struct diff_filepair *p, int i)
1919 {
1920         diff_debug_filespec(p->one, i, "one");
1921         diff_debug_filespec(p->two, i, "two");
1922         fprintf(stderr, "score %d, status %c stays %d broken %d\n",
1923                 p->score, p->status ? p->status : '?',
1924                 p->source_stays, p->broken_pair);
1925 }
1926
1927 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
1928 {
1929         int i;
1930         if (msg)
1931                 fprintf(stderr, "%s\n", msg);
1932         fprintf(stderr, "q->nr = %d\n", q->nr);
1933         for (i = 0; i < q->nr; i++) {
1934                 struct diff_filepair *p = q->queue[i];
1935                 diff_debug_filepair(p, i);
1936         }
1937 }
1938 #endif
1939
1940 static void diff_resolve_rename_copy(void)
1941 {
1942         int i, j;
1943         struct diff_filepair *p, *pp;
1944         struct diff_queue_struct *q = &diff_queued_diff;
1945
1946         diff_debug_queue("resolve-rename-copy", q);
1947
1948         for (i = 0; i < q->nr; i++) {
1949                 p = q->queue[i];
1950                 p->status = 0; /* undecided */
1951                 if (DIFF_PAIR_UNMERGED(p))
1952                         p->status = DIFF_STATUS_UNMERGED;
1953                 else if (!DIFF_FILE_VALID(p->one))
1954                         p->status = DIFF_STATUS_ADDED;
1955                 else if (!DIFF_FILE_VALID(p->two))
1956                         p->status = DIFF_STATUS_DELETED;
1957                 else if (DIFF_PAIR_TYPE_CHANGED(p))
1958                         p->status = DIFF_STATUS_TYPE_CHANGED;
1959
1960                 /* from this point on, we are dealing with a pair
1961                  * whose both sides are valid and of the same type, i.e.
1962                  * either in-place edit or rename/copy edit.
1963                  */
1964                 else if (DIFF_PAIR_RENAME(p)) {
1965                         if (p->source_stays) {
1966                                 p->status = DIFF_STATUS_COPIED;
1967                                 continue;
1968                         }
1969                         /* See if there is some other filepair that
1970                          * copies from the same source as us.  If so
1971                          * we are a copy.  Otherwise we are either a
1972                          * copy if the path stays, or a rename if it
1973                          * does not, but we already handled "stays" case.
1974                          */
1975                         for (j = i + 1; j < q->nr; j++) {
1976                                 pp = q->queue[j];
1977                                 if (strcmp(pp->one->path, p->one->path))
1978                                         continue; /* not us */
1979                                 if (!DIFF_PAIR_RENAME(pp))
1980                                         continue; /* not a rename/copy */
1981                                 /* pp is a rename/copy from the same source */
1982                                 p->status = DIFF_STATUS_COPIED;
1983                                 break;
1984                         }
1985                         if (!p->status)
1986                                 p->status = DIFF_STATUS_RENAMED;
1987                 }
1988                 else if (memcmp(p->one->sha1, p->two->sha1, 20) ||
1989                          p->one->mode != p->two->mode)
1990                         p->status = DIFF_STATUS_MODIFIED;
1991                 else {
1992                         /* This is a "no-change" entry and should not
1993                          * happen anymore, but prepare for broken callers.
1994                          */
1995                         error("feeding unmodified %s to diffcore",
1996                               p->one->path);
1997                         p->status = DIFF_STATUS_UNKNOWN;
1998                 }
1999         }
2000         diff_debug_queue("resolve-rename-copy done", q);
2001 }
2002
2003 static int check_pair_status(struct diff_filepair *p)
2004 {
2005         switch (p->status) {
2006         case DIFF_STATUS_UNKNOWN:
2007                 return 0;
2008         case 0:
2009                 die("internal error in diff-resolve-rename-copy");
2010         default:
2011                 return 1;
2012         }
2013 }
2014
2015 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
2016 {
2017         int fmt = opt->output_format;
2018
2019         if (fmt & DIFF_FORMAT_CHECKDIFF)
2020                 diff_flush_checkdiff(p, opt);
2021         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
2022                 diff_flush_raw(p, opt);
2023         else if (fmt & DIFF_FORMAT_NAME)
2024                 diff_flush_name(p, opt->line_termination);
2025 }
2026
2027 static void show_file_mode_name(const char *newdelete, struct diff_filespec *fs)
2028 {
2029         if (fs->mode)
2030                 printf(" %s mode %06o %s\n", newdelete, fs->mode, fs->path);
2031         else
2032                 printf(" %s %s\n", newdelete, fs->path);
2033 }
2034
2035
2036 static void show_mode_change(struct diff_filepair *p, int show_name)
2037 {
2038         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
2039                 if (show_name)
2040                         printf(" mode change %06o => %06o %s\n",
2041                                p->one->mode, p->two->mode, p->two->path);
2042                 else
2043                         printf(" mode change %06o => %06o\n",
2044                                p->one->mode, p->two->mode);
2045         }
2046 }
2047
2048 static void show_rename_copy(const char *renamecopy, struct diff_filepair *p)
2049 {
2050         const char *old, *new;
2051
2052         /* Find common prefix */
2053         old = p->one->path;
2054         new = p->two->path;
2055         while (1) {
2056                 const char *slash_old, *slash_new;
2057                 slash_old = strchr(old, '/');
2058                 slash_new = strchr(new, '/');
2059                 if (!slash_old ||
2060                     !slash_new ||
2061                     slash_old - old != slash_new - new ||
2062                     memcmp(old, new, slash_new - new))
2063                         break;
2064                 old = slash_old + 1;
2065                 new = slash_new + 1;
2066         }
2067         /* p->one->path thru old is the common prefix, and old and new
2068          * through the end of names are renames
2069          */
2070         if (old != p->one->path)
2071                 printf(" %s %.*s{%s => %s} (%d%%)\n", renamecopy,
2072                        (int)(old - p->one->path), p->one->path,
2073                        old, new, (int)(0.5 + p->score * 100.0/MAX_SCORE));
2074         else
2075                 printf(" %s %s => %s (%d%%)\n", renamecopy,
2076                        p->one->path, p->two->path,
2077                        (int)(0.5 + p->score * 100.0/MAX_SCORE));
2078         show_mode_change(p, 0);
2079 }
2080
2081 static void diff_summary(struct diff_filepair *p)
2082 {
2083         switch(p->status) {
2084         case DIFF_STATUS_DELETED:
2085                 show_file_mode_name("delete", p->one);
2086                 break;
2087         case DIFF_STATUS_ADDED:
2088                 show_file_mode_name("create", p->two);
2089                 break;
2090         case DIFF_STATUS_COPIED:
2091                 show_rename_copy("copy", p);
2092                 break;
2093         case DIFF_STATUS_RENAMED:
2094                 show_rename_copy("rename", p);
2095                 break;
2096         default:
2097                 if (p->score) {
2098                         printf(" rewrite %s (%d%%)\n", p->two->path,
2099                                 (int)(0.5 + p->score * 100.0/MAX_SCORE));
2100                         show_mode_change(p, 0);
2101                 } else  show_mode_change(p, 1);
2102                 break;
2103         }
2104 }
2105
2106 struct patch_id_t {
2107         struct xdiff_emit_state xm;
2108         SHA_CTX *ctx;
2109         int patchlen;
2110 };
2111
2112 static int remove_space(char *line, int len)
2113 {
2114         int i;
2115         char *dst = line;
2116         unsigned char c;
2117
2118         for (i = 0; i < len; i++)
2119                 if (!isspace((c = line[i])))
2120                         *dst++ = c;
2121
2122         return dst - line;
2123 }
2124
2125 static void patch_id_consume(void *priv, char *line, unsigned long len)
2126 {
2127         struct patch_id_t *data = priv;
2128         int new_len;
2129
2130         /* Ignore line numbers when computing the SHA1 of the patch */
2131         if (!strncmp(line, "@@ -", 4))
2132                 return;
2133
2134         new_len = remove_space(line, len);
2135
2136         SHA1_Update(data->ctx, line, new_len);
2137         data->patchlen += new_len;
2138 }
2139
2140 /* returns 0 upon success, and writes result into sha1 */
2141 static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
2142 {
2143         struct diff_queue_struct *q = &diff_queued_diff;
2144         int i;
2145         SHA_CTX ctx;
2146         struct patch_id_t data;
2147         char buffer[PATH_MAX * 4 + 20];
2148
2149         SHA1_Init(&ctx);
2150         memset(&data, 0, sizeof(struct patch_id_t));
2151         data.ctx = &ctx;
2152         data.xm.consume = patch_id_consume;
2153
2154         for (i = 0; i < q->nr; i++) {
2155                 xpparam_t xpp;
2156                 xdemitconf_t xecfg;
2157                 xdemitcb_t ecb;
2158                 mmfile_t mf1, mf2;
2159                 struct diff_filepair *p = q->queue[i];
2160                 int len1, len2;
2161
2162                 if (p->status == 0)
2163                         return error("internal diff status error");
2164                 if (p->status == DIFF_STATUS_UNKNOWN)
2165                         continue;
2166                 if (diff_unmodified_pair(p))
2167                         continue;
2168                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2169                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2170                         continue;
2171                 if (DIFF_PAIR_UNMERGED(p))
2172                         continue;
2173
2174                 diff_fill_sha1_info(p->one);
2175                 diff_fill_sha1_info(p->two);
2176                 if (fill_mmfile(&mf1, p->one) < 0 ||
2177                                 fill_mmfile(&mf2, p->two) < 0)
2178                         return error("unable to read files to diff");
2179
2180                 /* Maybe hash p->two? into the patch id? */
2181                 if (mmfile_is_binary(&mf2))
2182                         continue;
2183
2184                 len1 = remove_space(p->one->path, strlen(p->one->path));
2185                 len2 = remove_space(p->two->path, strlen(p->two->path));
2186                 if (p->one->mode == 0)
2187                         len1 = snprintf(buffer, sizeof(buffer),
2188                                         "diff--gita/%.*sb/%.*s"
2189                                         "newfilemode%06o"
2190                                         "---/dev/null"
2191                                         "+++b/%.*s",
2192                                         len1, p->one->path,
2193                                         len2, p->two->path,
2194                                         p->two->mode,
2195                                         len2, p->two->path);
2196                 else if (p->two->mode == 0)
2197                         len1 = snprintf(buffer, sizeof(buffer),
2198                                         "diff--gita/%.*sb/%.*s"
2199                                         "deletedfilemode%06o"
2200                                         "---a/%.*s"
2201                                         "+++/dev/null",
2202                                         len1, p->one->path,
2203                                         len2, p->two->path,
2204                                         p->one->mode,
2205                                         len1, p->one->path);
2206                 else
2207                         len1 = snprintf(buffer, sizeof(buffer),
2208                                         "diff--gita/%.*sb/%.*s"
2209                                         "---a/%.*s"
2210                                         "+++b/%.*s",
2211                                         len1, p->one->path,
2212                                         len2, p->two->path,
2213                                         len1, p->one->path,
2214                                         len2, p->two->path);
2215                 SHA1_Update(&ctx, buffer, len1);
2216
2217                 xpp.flags = XDF_NEED_MINIMAL;
2218                 xecfg.ctxlen = 3;
2219                 xecfg.flags = XDL_EMIT_FUNCNAMES;
2220                 ecb.outf = xdiff_outf;
2221                 ecb.priv = &data;
2222                 xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
2223         }
2224
2225         SHA1_Final(sha1, &ctx);
2226         return 0;
2227 }
2228
2229 int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
2230 {
2231         struct diff_queue_struct *q = &diff_queued_diff;
2232         int i;
2233         int result = diff_get_patch_id(options, sha1);
2234
2235         for (i = 0; i < q->nr; i++)
2236                 diff_free_filepair(q->queue[i]);
2237
2238         free(q->queue);
2239         q->queue = NULL;
2240         q->nr = q->alloc = 0;
2241
2242         return result;
2243 }
2244
2245 static int is_summary_empty(const struct diff_queue_struct *q)
2246 {
2247         int i;
2248
2249         for (i = 0; i < q->nr; i++) {
2250                 const struct diff_filepair *p = q->queue[i];
2251
2252                 switch (p->status) {
2253                 case DIFF_STATUS_DELETED:
2254                 case DIFF_STATUS_ADDED:
2255                 case DIFF_STATUS_COPIED:
2256                 case DIFF_STATUS_RENAMED:
2257                         return 0;
2258                 default:
2259                         if (p->score)
2260                                 return 0;
2261                         if (p->one->mode && p->two->mode &&
2262                             p->one->mode != p->two->mode)
2263                                 return 0;
2264                         break;
2265                 }
2266         }
2267         return 1;
2268 }
2269
2270 void diff_flush(struct diff_options *options)
2271 {
2272         struct diff_queue_struct *q = &diff_queued_diff;
2273         int i, output_format = options->output_format;
2274         int separator = 0;
2275
2276         /*
2277          * Order: raw, stat, summary, patch
2278          * or:    name/name-status/checkdiff (other bits clear)
2279          */
2280         if (!q->nr)
2281                 goto free_queue;
2282
2283         if (output_format & (DIFF_FORMAT_RAW |
2284                              DIFF_FORMAT_NAME |
2285                              DIFF_FORMAT_NAME_STATUS |
2286                              DIFF_FORMAT_CHECKDIFF)) {
2287                 for (i = 0; i < q->nr; i++) {
2288                         struct diff_filepair *p = q->queue[i];
2289                         if (check_pair_status(p))
2290                                 flush_one_pair(p, options);
2291                 }
2292                 separator++;
2293         }
2294
2295         if (output_format & DIFF_FORMAT_DIFFSTAT) {
2296                 struct diffstat_t diffstat;
2297
2298                 memset(&diffstat, 0, sizeof(struct diffstat_t));
2299                 diffstat.xm.consume = diffstat_consume;
2300                 for (i = 0; i < q->nr; i++) {
2301                         struct diff_filepair *p = q->queue[i];
2302                         if (check_pair_status(p))
2303                                 diff_flush_stat(p, options, &diffstat);
2304                 }
2305                 show_stats(&diffstat);
2306                 separator++;
2307         }
2308
2309         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
2310                 for (i = 0; i < q->nr; i++)
2311                         diff_summary(q->queue[i]);
2312                 separator++;
2313         }
2314
2315         if (output_format & DIFF_FORMAT_PATCH) {
2316                 if (separator) {
2317                         if (options->stat_sep) {
2318                                 /* attach patch instead of inline */
2319                                 fputs(options->stat_sep, stdout);
2320                         } else {
2321                                 putchar(options->line_termination);
2322                         }
2323                 }
2324
2325                 for (i = 0; i < q->nr; i++) {
2326                         struct diff_filepair *p = q->queue[i];
2327                         if (check_pair_status(p))
2328                                 diff_flush_patch(p, options);
2329                 }
2330         }
2331
2332         for (i = 0; i < q->nr; i++)
2333                 diff_free_filepair(q->queue[i]);
2334 free_queue:
2335         free(q->queue);
2336         q->queue = NULL;
2337         q->nr = q->alloc = 0;
2338 }
2339
2340 static void diffcore_apply_filter(const char *filter)
2341 {
2342         int i;
2343         struct diff_queue_struct *q = &diff_queued_diff;
2344         struct diff_queue_struct outq;
2345         outq.queue = NULL;
2346         outq.nr = outq.alloc = 0;
2347
2348         if (!filter)
2349                 return;
2350
2351         if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
2352                 int found;
2353                 for (i = found = 0; !found && i < q->nr; i++) {
2354                         struct diff_filepair *p = q->queue[i];
2355                         if (((p->status == DIFF_STATUS_MODIFIED) &&
2356                              ((p->score &&
2357                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
2358                               (!p->score &&
2359                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
2360                             ((p->status != DIFF_STATUS_MODIFIED) &&
2361                              strchr(filter, p->status)))
2362                                 found++;
2363                 }
2364                 if (found)
2365                         return;
2366
2367                 /* otherwise we will clear the whole queue
2368                  * by copying the empty outq at the end of this
2369                  * function, but first clear the current entries
2370                  * in the queue.
2371                  */
2372                 for (i = 0; i < q->nr; i++)
2373                         diff_free_filepair(q->queue[i]);
2374         }
2375         else {
2376                 /* Only the matching ones */
2377                 for (i = 0; i < q->nr; i++) {
2378                         struct diff_filepair *p = q->queue[i];
2379
2380                         if (((p->status == DIFF_STATUS_MODIFIED) &&
2381                              ((p->score &&
2382                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
2383                               (!p->score &&
2384                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
2385                             ((p->status != DIFF_STATUS_MODIFIED) &&
2386                              strchr(filter, p->status)))
2387                                 diff_q(&outq, p);
2388                         else
2389                                 diff_free_filepair(p);
2390                 }
2391         }
2392         free(q->queue);
2393         *q = outq;
2394 }
2395
2396 void diffcore_std(struct diff_options *options)
2397 {
2398         if (options->break_opt != -1)
2399                 diffcore_break(options->break_opt);
2400         if (options->detect_rename)
2401                 diffcore_rename(options);
2402         if (options->break_opt != -1)
2403                 diffcore_merge_broken();
2404         if (options->pickaxe)
2405                 diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
2406         if (options->orderfile)
2407                 diffcore_order(options->orderfile);
2408         diff_resolve_rename_copy();
2409         diffcore_apply_filter(options->filter);
2410 }
2411
2412
2413 void diffcore_std_no_resolve(struct diff_options *options)
2414 {
2415         if (options->pickaxe)
2416                 diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
2417         if (options->orderfile)
2418                 diffcore_order(options->orderfile);
2419         diffcore_apply_filter(options->filter);
2420 }
2421
2422 void diff_addremove(struct diff_options *options,
2423                     int addremove, unsigned mode,
2424                     const unsigned char *sha1,
2425                     const char *base, const char *path)
2426 {
2427         char concatpath[PATH_MAX];
2428         struct diff_filespec *one, *two;
2429
2430         /* This may look odd, but it is a preparation for
2431          * feeding "there are unchanged files which should
2432          * not produce diffs, but when you are doing copy
2433          * detection you would need them, so here they are"
2434          * entries to the diff-core.  They will be prefixed
2435          * with something like '=' or '*' (I haven't decided
2436          * which but should not make any difference).
2437          * Feeding the same new and old to diff_change()
2438          * also has the same effect.
2439          * Before the final output happens, they are pruned after
2440          * merged into rename/copy pairs as appropriate.
2441          */
2442         if (options->reverse_diff)
2443                 addremove = (addremove == '+' ? '-' :
2444                              addremove == '-' ? '+' : addremove);
2445
2446         if (!path) path = "";
2447         sprintf(concatpath, "%s%s", base, path);
2448         one = alloc_filespec(concatpath);
2449         two = alloc_filespec(concatpath);
2450
2451         if (addremove != '+')
2452                 fill_filespec(one, sha1, mode);
2453         if (addremove != '-')
2454                 fill_filespec(two, sha1, mode);
2455
2456         diff_queue(&diff_queued_diff, one, two);
2457 }
2458
2459 void diff_change(struct diff_options *options,
2460                  unsigned old_mode, unsigned new_mode,
2461                  const unsigned char *old_sha1,
2462                  const unsigned char *new_sha1,
2463                  const char *base, const char *path)
2464 {
2465         char concatpath[PATH_MAX];
2466         struct diff_filespec *one, *two;
2467
2468         if (options->reverse_diff) {
2469                 unsigned tmp;
2470                 const unsigned char *tmp_c;
2471                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
2472                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
2473         }
2474         if (!path) path = "";
2475         sprintf(concatpath, "%s%s", base, path);
2476         one = alloc_filespec(concatpath);
2477         two = alloc_filespec(concatpath);
2478         fill_filespec(one, old_sha1, old_mode);
2479         fill_filespec(two, new_sha1, new_mode);
2480
2481         diff_queue(&diff_queued_diff, one, two);
2482 }
2483
2484 void diff_unmerge(struct diff_options *options,
2485                   const char *path)
2486 {
2487         struct diff_filespec *one, *two;
2488         one = alloc_filespec(path);
2489         two = alloc_filespec(path);
2490         diff_queue(&diff_queued_diff, one, two);
2491 }