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_detect_rename_default = 0;
  17 static int diff_rename_limit_default = -1;
  18 static int diff_use_color_default = 0;
  19
  20 enum color_diff {
  21         DIFF_RESET = 0,
  22         DIFF_PLAIN = 1,
  23         DIFF_METAINFO = 2,
  24         DIFF_FRAGINFO = 3,
  25         DIFF_FILE_OLD = 4,
  26         DIFF_FILE_NEW = 5,
  27 };
  28
  29 #define COLOR_NORMAL  ""
  30 #define COLOR_BOLD    "\033[1m"
  31 #define COLOR_DIM     "\033[2m"
  32 #define COLOR_UL      "\033[4m"
  33 #define COLOR_BLINK   "\033[5m"
  34 #define COLOR_REVERSE "\033[7m"
  35 #define COLOR_RESET   "\033[m"
  36
  37 #define COLOR_BLACK   "\033[30m"
  38 #define COLOR_RED     "\033[31m"
  39 #define COLOR_GREEN   "\033[32m"
  40 #define COLOR_YELLOW  "\033[33m"
  41 #define COLOR_BLUE    "\033[34m"
  42 #define COLOR_MAGENTA "\033[35m"
  43 #define COLOR_CYAN    "\033[36m"
  44 #define COLOR_WHITE   "\033[37m"
  45
  46 static const char *diff_colors[] = {
  47         [DIFF_RESET]    = COLOR_RESET,
  48         [DIFF_PLAIN]    = COLOR_NORMAL,
  49         [DIFF_METAINFO] = COLOR_BOLD,
  50         [DIFF_FRAGINFO] = COLOR_CYAN,
  51         [DIFF_FILE_OLD] = COLOR_RED,
  52         [DIFF_FILE_NEW] = COLOR_GREEN,
  53 };
  54
  55 static int parse_diff_color_slot(const char *var, int ofs)
  56 {
  57         if (!strcasecmp(var+ofs, "plain"))
  58                 return DIFF_PLAIN;
  59         if (!strcasecmp(var+ofs, "meta"))
  60                 return DIFF_METAINFO;
  61         if (!strcasecmp(var+ofs, "frag"))
  62                 return DIFF_FRAGINFO;
  63         if (!strcasecmp(var+ofs, "old"))
  64                 return DIFF_FILE_OLD;
  65         if (!strcasecmp(var+ofs, "new"))
  66                 return DIFF_FILE_NEW;
  67         die("bad config variable '%s'", var);
  68 }
  69
  70 static const char *parse_diff_color_value(const char *value, const char *var)
  71 {
  72         if (!strcasecmp(value, "normal"))
  73                 return COLOR_NORMAL;
  74         if (!strcasecmp(value, "bold"))
  75                 return COLOR_BOLD;
  76         if (!strcasecmp(value, "dim"))
  77                 return COLOR_DIM;
  78         if (!strcasecmp(value, "ul"))
  79                 return COLOR_UL;
  80         if (!strcasecmp(value, "blink"))
  81                 return COLOR_BLINK;
  82         if (!strcasecmp(value, "reverse"))
  83                 return COLOR_REVERSE;
  84         if (!strcasecmp(value, "reset"))
  85                 return COLOR_RESET;
  86         if (!strcasecmp(value, "black"))
  87                 return COLOR_BLACK;
  88         if (!strcasecmp(value, "red"))
  89                 return COLOR_RED;
  90         if (!strcasecmp(value, "green"))
  91                 return COLOR_GREEN;
  92         if (!strcasecmp(value, "yellow"))
  93                 return COLOR_YELLOW;
  94         if (!strcasecmp(value, "blue"))
  95                 return COLOR_BLUE;
  96         if (!strcasecmp(value, "magenta"))
  97                 return COLOR_MAGENTA;
  98         if (!strcasecmp(value, "cyan"))
  99                 return COLOR_CYAN;
 100         if (!strcasecmp(value, "white"))
 101                 return COLOR_WHITE;
 102         die("bad config value '%s' for variable '%s'", value, var);
 103 }
 104
 105 int git_diff_config(const char *var, const char *value)
 106 {
 107         if (!strcmp(var, "diff.renamelimit")) {
 108                 diff_rename_limit_default = git_config_int(var, value);
 109                 return 0;
 110         }
 111         if (!strcmp(var, "diff.color")) {
 112                 if (!value)
 113                         diff_use_color_default = 1; /* bool */
 114                 else if (!strcasecmp(value, "auto"))
 115                         diff_use_color_default = isatty(1);
 116                 else if (!strcasecmp(value, "never"))
 117                         diff_use_color_default = 0;
 118                 else if (!strcasecmp(value, "always"))
 119                         diff_use_color_default = 1;
 120                 else
 121                         diff_use_color_default = git_config_bool(var, value);
 122                 return 0;
 123         }
 124         if (!strcmp(var, "diff.renames")) {
 125                 if (!value)
 126                         diff_detect_rename_default = DIFF_DETECT_RENAME;
 127                 else if (!strcasecmp(value, "copies") ||
 128                          !strcasecmp(value, "copy"))
 129                         diff_detect_rename_default = DIFF_DETECT_COPY;
 130                 else if (git_config_bool(var,value))
 131                         diff_detect_rename_default = DIFF_DETECT_RENAME;
 132                 return 0;
 133         }
 134         if (!strncmp(var, "diff.color.", 11)) {
 135                 int slot = parse_diff_color_slot(var, 11);
 136                 diff_colors[slot] = parse_diff_color_value(value, var);
 137                 return 0;
 138         }
 139         return git_default_config(var, value);
 140 }
 141
 142 static char *quote_one(const char *str)
 143 {
 144         int needlen;
 145         char *xp;
 146
 147         if (!str)
 148                 return NULL;
 149         needlen = quote_c_style(str, NULL, NULL, 0);
 150         if (!needlen)
 151                 return strdup(str);
 152         xp = xmalloc(needlen + 1);
 153         quote_c_style(str, xp, NULL, 0);
 154         return xp;
 155 }
 156
 157 static char *quote_two(const char *one, const char *two)
 158 {
 159         int need_one = quote_c_style(one, NULL, NULL, 1);
 160         int need_two = quote_c_style(two, NULL, NULL, 1);
 161         char *xp;
 162
 163         if (need_one + need_two) {
 164                 if (!need_one) need_one = strlen(one);
 165                 if (!need_two) need_one = strlen(two);
 166
 167                 xp = xmalloc(need_one + need_two + 3);
 168                 xp[0] = '"';
 169                 quote_c_style(one, xp + 1, NULL, 1);
 170                 quote_c_style(two, xp + need_one + 1, NULL, 1);
 171                 strcpy(xp + need_one + need_two + 1, "\"");
 172                 return xp;
 173         }
 174         need_one = strlen(one);
 175         need_two = strlen(two);
 176         xp = xmalloc(need_one + need_two + 1);
 177         strcpy(xp, one);
 178         strcpy(xp + need_one, two);
 179         return xp;
 180 }
 181
 182 static const char *external_diff(void)
 183 {
 184         static const char *external_diff_cmd = NULL;
 185         static int done_preparing = 0;
 186
 187         if (done_preparing)
 188                 return external_diff_cmd;
 189         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 190         done_preparing = 1;
 191         return external_diff_cmd;
 192 }
 193
 194 #define TEMPFILE_PATH_LEN               50
 195
 196 static struct diff_tempfile {
 197         const char *name; /* filename external diff should read from */
 198         char hex[41];
 199         char mode[10];
 200         char tmp_path[TEMPFILE_PATH_LEN];
 201 } diff_temp[2];
 202
 203 static int count_lines(const char *data, int size)
 204 {
 205         int count, ch, completely_empty = 1, nl_just_seen = 0;
 206         count = 0;
 207         while (0 < size--) {
 208                 ch = *data++;
 209                 if (ch == '\n') {
 210                         count++;
 211                         nl_just_seen = 1;
 212                         completely_empty = 0;
 213                 }
 214                 else {
 215                         nl_just_seen = 0;
 216                         completely_empty = 0;
 217                 }
 218         }
 219         if (completely_empty)
 220                 return 0;
 221         if (!nl_just_seen)
 222                 count++; /* no trailing newline */
 223         return count;
 224 }
 225
 226 static void print_line_count(int count)
 227 {
 228         switch (count) {
 229         case 0:
 230                 printf("0,0");
 231                 break;
 232         case 1:
 233                 printf("1");
 234                 break;
 235         default:
 236                 printf("1,%d", count);
 237                 break;
 238         }
 239 }
 240
 241 static void copy_file(int prefix, const char *data, int size)
 242 {
 243         int ch, nl_just_seen = 1;
 244         while (0 < size--) {
 245                 ch = *data++;
 246                 if (nl_just_seen)
 247                         putchar(prefix);
 248                 putchar(ch);
 249                 if (ch == '\n')
 250                         nl_just_seen = 1;
 251                 else
 252                         nl_just_seen = 0;
 253         }
 254         if (!nl_just_seen)
 255                 printf("\n\\ No newline at end of file\n");
 256 }
 257
 258 static void emit_rewrite_diff(const char *name_a,
 259                               const char *name_b,
 260                               struct diff_filespec *one,
 261                               struct diff_filespec *two)
 262 {
 263         int lc_a, lc_b;
 264         diff_populate_filespec(one, 0);
 265         diff_populate_filespec(two, 0);
 266         lc_a = count_lines(one->data, one->size);
 267         lc_b = count_lines(two->data, two->size);
 268         printf("--- %s\n+++ %s\n@@ -", name_a, name_b);
 269         print_line_count(lc_a);
 270         printf(" +");
 271         print_line_count(lc_b);
 272         printf(" @@\n");
 273         if (lc_a)
 274                 copy_file('-', one->data, one->size);
 275         if (lc_b)
 276                 copy_file('+', two->data, two->size);
 277 }
 278
 279 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 280 {
 281         if (!DIFF_FILE_VALID(one)) {
 282                 mf->ptr = (char *)""; /* does not matter */
 283                 mf->size = 0;
 284                 return 0;
 285         }
 286         else if (diff_populate_filespec(one, 0))
 287                 return -1;
 288         mf->ptr = one->data;
 289         mf->size = one->size;
 290         return 0;
 291 }
 292
 293 struct emit_callback {
 294         struct xdiff_emit_state xm;
 295         int nparents, color_diff;
 296         const char **label_path;
 297 };
 298
 299 static inline const char *get_color(int diff_use_color, enum color_diff ix)
 300 {
 301         if (diff_use_color)
 302                 return diff_colors[ix];
 303         return "";
 304 }
 305
 306 static void fn_out_consume(void *priv, char *line, unsigned long len)
 307 {
 308         int i;
 309         struct emit_callback *ecbdata = priv;
 310         const char *set = get_color(ecbdata->color_diff, DIFF_METAINFO);
 311         const char *reset = get_color(ecbdata->color_diff, DIFF_RESET);
 312
 313         if (ecbdata->label_path[0]) {
 314                 printf("%s--- %s%s\n", set, ecbdata->label_path[0], reset);
 315                 printf("%s+++ %s%s\n", set, ecbdata->label_path[1], reset);
 316                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
 317         }
 318
 319         /* This is not really necessary for now because
 320          * this codepath only deals with two-way diffs.
 321          */
 322         for (i = 0; i < len && line[i] == '@'; i++)
 323                 ;
 324         if (2 <= i && i < len && line[i] == ' ') {
 325                 ecbdata->nparents = i - 1;
 326                 set = get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 327         }
 328         else if (len < ecbdata->nparents)
 329                 set = reset;
 330         else {
 331                 int nparents = ecbdata->nparents;
 332                 int color = DIFF_PLAIN;
 333                 for (i = 0; i < nparents && len; i++) {
 334                         if (line[i] == '-')
 335                                 color = DIFF_FILE_OLD;
 336                         else if (line[i] == '+')
 337                                 color = DIFF_FILE_NEW;
 338                 }
 339                 set = get_color(ecbdata->color_diff, color);
 340         }
 341         if (len > 0 && line[len-1] == '\n')
 342                 len--;
 343         fputs (set, stdout);
 344         fwrite (line, len, 1, stdout);
 345         puts (reset);
 346 }
 347
 348 static char *pprint_rename(const char *a, const char *b)
 349 {
 350         const char *old = a;
 351         const char *new = b;
 352         char *name = NULL;
 353         int pfx_length, sfx_length;
 354         int len_a = strlen(a);
 355         int len_b = strlen(b);
 356
 357         /* Find common prefix */
 358         pfx_length = 0;
 359         while (*old && *new && *old == *new) {
 360                 if (*old == '/')
 361                         pfx_length = old - a + 1;
 362                 old++;
 363                 new++;
 364         }
 365
 366         /* Find common suffix */
 367         old = a + len_a;
 368         new = b + len_b;
 369         sfx_length = 0;
 370         while (a <= old && b <= new && *old == *new) {
 371                 if (*old == '/')
 372                         sfx_length = len_a - (old - a);
 373                 old--;
 374                 new--;
 375         }
 376
 377         /*
 378          * pfx{mid-a => mid-b}sfx
 379          * {pfx-a => pfx-b}sfx
 380          * pfx{sfx-a => sfx-b}
 381          * name-a => name-b
 382          */
 383         if (pfx_length + sfx_length) {
 384                 int a_midlen = len_a - pfx_length - sfx_length;
 385                 int b_midlen = len_b - pfx_length - sfx_length;
 386                 if (a_midlen < 0) a_midlen = 0;
 387                 if (b_midlen < 0) b_midlen = 0;
 388
 389                 name = xmalloc(pfx_length + a_midlen + b_midlen + sfx_length + 7);
 390                 sprintf(name, "%.*s{%.*s => %.*s}%s",
 391                         pfx_length, a,
 392                         a_midlen, a + pfx_length,
 393                         b_midlen, b + pfx_length,
 394                         a + len_a - sfx_length);
 395         }
 396         else {
 397                 name = xmalloc(len_a + len_b + 5);
 398                 sprintf(name, "%s => %s", a, b);
 399         }
 400         return name;
 401 }
 402
 403 struct diffstat_t {
 404         struct xdiff_emit_state xm;
 405
 406         int nr;
 407         int alloc;
 408         struct diffstat_file {
 409                 char *name;
 410                 unsigned is_unmerged:1;
 411                 unsigned is_binary:1;
 412                 unsigned is_renamed:1;
 413                 unsigned int added, deleted;
 414         } **files;
 415 };
 416
 417 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
 418                                           const char *name_a,
 419                                           const char *name_b)
 420 {
 421         struct diffstat_file *x;
 422         x = xcalloc(sizeof (*x), 1);
 423         if (diffstat->nr == diffstat->alloc) {
 424                 diffstat->alloc = alloc_nr(diffstat->alloc);
 425                 diffstat->files = xrealloc(diffstat->files,
 426                                 diffstat->alloc * sizeof(x));
 427         }
 428         diffstat->files[diffstat->nr++] = x;
 429         if (name_b) {
 430                 x->name = pprint_rename(name_a, name_b);
 431                 x->is_renamed = 1;
 432         }
 433         else
 434                 x->name = strdup(name_a);
 435         return x;
 436 }
 437
 438 static void diffstat_consume(void *priv, char *line, unsigned long len)
 439 {
 440         struct diffstat_t *diffstat = priv;
 441         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
 442
 443         if (line[0] == '+')
 444                 x->added++;
 445         else if (line[0] == '-')
 446                 x->deleted++;
 447 }
 448
 449 static const char pluses[] = "++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++";
 450 static const char minuses[]= "----------------------------------------------------------------------";
 451 const char mime_boundary_leader[] = "------------";
 452
 453 static void show_stats(struct diffstat_t* data)
 454 {
 455         int i, len, add, del, total, adds = 0, dels = 0;
 456         int max, max_change = 0, max_len = 0;
 457         int total_files = data->nr;
 458
 459         if (data->nr == 0)
 460                 return;
 461
 462         for (i = 0; i < data->nr; i++) {
 463                 struct diffstat_file *file = data->files[i];
 464
 465                 len = strlen(file->name);
 466                 if (max_len < len)
 467                         max_len = len;
 468
 469                 if (file->is_binary || file->is_unmerged)
 470                         continue;
 471                 if (max_change < file->added + file->deleted)
 472                         max_change = file->added + file->deleted;
 473         }
 474
 475         for (i = 0; i < data->nr; i++) {
 476                 const char *prefix = "";
 477                 char *name = data->files[i]->name;
 478                 int added = data->files[i]->added;
 479                 int deleted = data->files[i]->deleted;
 480
 481                 if (0 < (len = quote_c_style(name, NULL, NULL, 0))) {
 482                         char *qname = xmalloc(len + 1);
 483                         quote_c_style(name, qname, NULL, 0);
 484                         free(name);
 485                         data->files[i]->name = name = qname;
 486                 }
 487
 488                 /*
 489                  * "scale" the filename
 490                  */
 491                 len = strlen(name);
 492                 max = max_len;
 493                 if (max > 50)
 494                         max = 50;
 495                 if (len > max) {
 496                         char *slash;
 497                         prefix = "...";
 498                         max -= 3;
 499                         name += len - max;
 500                         slash = strchr(name, '/');
 501                         if (slash)
 502                                 name = slash;
 503                 }
 504                 len = max;
 505
 506                 /*
 507                  * scale the add/delete
 508                  */
 509                 max = max_change;
 510                 if (max + len > 70)
 511                         max = 70 - len;
 512
 513                 if (data->files[i]->is_binary) {
 514                         printf(" %s%-*s |  Bin\n", prefix, len, name);
 515                         goto free_diffstat_file;
 516                 }
 517                 else if (data->files[i]->is_unmerged) {
 518                         printf(" %s%-*s |  Unmerged\n", prefix, len, name);
 519                         goto free_diffstat_file;
 520                 }
 521                 else if (!data->files[i]->is_renamed &&
 522                          (added + deleted == 0)) {
 523                         total_files--;
 524                         goto free_diffstat_file;
 525                 }
 526
 527                 add = added;
 528                 del = deleted;
 529                 total = add + del;
 530                 adds += add;
 531                 dels += del;
 532
 533                 if (max_change > 0) {
 534                         total = (total * max + max_change / 2) / max_change;
 535                         add = (add * max + max_change / 2) / max_change;
 536                         del = total - add;
 537                 }
 538                 printf(" %s%-*s |%5d %.*s%.*s\n", prefix,
 539                                 len, name, added + deleted,
 540                                 add, pluses, del, minuses);
 541         free_diffstat_file:
 542                 free(data->files[i]->name);
 543                 free(data->files[i]);
 544         }
 545         free(data->files);
 546         printf(" %d files changed, %d insertions(+), %d deletions(-)\n",
 547                         total_files, adds, dels);
 548 }
 549
 550 struct checkdiff_t {
 551         struct xdiff_emit_state xm;
 552         const char *filename;
 553         int lineno;
 554 };
 555
 556 static void checkdiff_consume(void *priv, char *line, unsigned long len)
 557 {
 558         struct checkdiff_t *data = priv;
 559
 560         if (line[0] == '+') {
 561                 int i, spaces = 0;
 562
 563                 data->lineno++;
 564
 565                 /* check space before tab */
 566                 for (i = 1; i < len && (line[i] == ' ' || line[i] == '\t'); i++)
 567                         if (line[i] == ' ')
 568                                 spaces++;
 569                 if (line[i - 1] == '\t' && spaces)
 570                         printf("%s:%d: space before tab:%.*s\n",
 571                                 data->filename, data->lineno, (int)len, line);
 572
 573                 /* check white space at line end */
 574                 if (line[len - 1] == '\n')
 575                         len--;
 576                 if (isspace(line[len - 1]))
 577                         printf("%s:%d: white space at end: %.*s\n",
 578                                 data->filename, data->lineno, (int)len, line);
 579         } else if (line[0] == ' ')
 580                 data->lineno++;
 581         else if (line[0] == '@') {
 582                 char *plus = strchr(line, '+');
 583                 if (plus)
 584                         data->lineno = strtol(plus, NULL, 10);
 585                 else
 586                         die("invalid diff");
 587         }
 588 }
 589
 590 static unsigned char *deflate_it(char *data,
 591                                  unsigned long size,
 592                                  unsigned long *result_size)
 593 {
 594         int bound;
 595         unsigned char *deflated;
 596         z_stream stream;
 597
 598         memset(&stream, 0, sizeof(stream));
 599         deflateInit(&stream, zlib_compression_level);
 600         bound = deflateBound(&stream, size);
 601         deflated = xmalloc(bound);
 602         stream.next_out = deflated;
 603         stream.avail_out = bound;
 604
 605         stream.next_in = (unsigned char *)data;
 606         stream.avail_in = size;
 607         while (deflate(&stream, Z_FINISH) == Z_OK)
 608                 ; /* nothing */
 609         deflateEnd(&stream);
 610         *result_size = stream.total_out;
 611         return deflated;
 612 }
 613
 614 static void emit_binary_diff(mmfile_t *one, mmfile_t *two)
 615 {
 616         void *cp;
 617         void *delta;
 618         void *deflated;
 619         void *data;
 620         unsigned long orig_size;
 621         unsigned long delta_size;
 622         unsigned long deflate_size;
 623         unsigned long data_size;
 624
 625         printf("GIT binary patch\n");
 626         /* We could do deflated delta, or we could do just deflated two,
 627          * whichever is smaller.
 628          */
 629         delta = NULL;
 630         deflated = deflate_it(two->ptr, two->size, &deflate_size);
 631         if (one->size && two->size) {
 632                 delta = diff_delta(one->ptr, one->size,
 633                                    two->ptr, two->size,
 634                                    &delta_size, deflate_size);
 635                 if (delta) {
 636                         void *to_free = delta;
 637                         orig_size = delta_size;
 638                         delta = deflate_it(delta, delta_size, &delta_size);
 639                         free(to_free);
 640                 }
 641         }
 642
 643         if (delta && delta_size < deflate_size) {
 644                 printf("delta %lu\n", orig_size);
 645                 free(deflated);
 646                 data = delta;
 647                 data_size = delta_size;
 648         }
 649         else {
 650                 printf("literal %lu\n", two->size);
 651                 free(delta);
 652                 data = deflated;
 653                 data_size = deflate_size;
 654         }
 655
 656         /* emit data encoded in base85 */
 657         cp = data;
 658         while (data_size) {
 659                 int bytes = (52 < data_size) ? 52 : data_size;
 660                 char line[70];
 661                 data_size -= bytes;
 662                 if (bytes <= 26)
 663                         line[0] = bytes + 'A' - 1;
 664                 else
 665                         line[0] = bytes - 26 + 'a' - 1;
 666                 encode_85(line + 1, cp, bytes);
 667                 cp = (char *) cp + bytes;
 668                 puts(line);
 669         }
 670         printf("\n");
 671         free(data);
 672 }
 673
 674 #define FIRST_FEW_BYTES 8000
 675 static int mmfile_is_binary(mmfile_t *mf)
 676 {
 677         long sz = mf->size;
 678         if (FIRST_FEW_BYTES < sz)
 679                 sz = FIRST_FEW_BYTES;
 680         if (memchr(mf->ptr, 0, sz))
 681                 return 1;
 682         return 0;
 683 }
 684
 685 static void builtin_diff(const char *name_a,
 686                          const char *name_b,
 687                          struct diff_filespec *one,
 688                          struct diff_filespec *two,
 689                          const char *xfrm_msg,
 690                          struct diff_options *o,
 691                          int complete_rewrite)
 692 {
 693         mmfile_t mf1, mf2;
 694         const char *lbl[2];
 695         char *a_one, *b_two;
 696         const char *set = get_color(o->color_diff, DIFF_METAINFO);
 697         const char *reset = get_color(o->color_diff, DIFF_RESET);
 698
 699         a_one = quote_two("a/", name_a);
 700         b_two = quote_two("b/", name_b);
 701         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
 702         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
 703         printf("%sdiff --git %s %s%s\n", set, a_one, b_two, reset);
 704         if (lbl[0][0] == '/') {
 705                 /* /dev/null */
 706                 printf("%snew file mode %06o%s\n", set, two->mode, reset);
 707                 if (xfrm_msg && xfrm_msg[0])
 708                         printf("%s%s%s\n", set, xfrm_msg, reset);
 709         }
 710         else if (lbl[1][0] == '/') {
 711                 printf("%sdeleted file mode %06o%s\n", set, one->mode, reset);
 712                 if (xfrm_msg && xfrm_msg[0])
 713                         printf("%s%s%s\n", set, xfrm_msg, reset);
 714         }
 715         else {
 716                 if (one->mode != two->mode) {
 717                         printf("%sold mode %06o%s\n", set, one->mode, reset);
 718                         printf("%snew mode %06o%s\n", set, two->mode, reset);
 719                 }
 720                 if (xfrm_msg && xfrm_msg[0])
 721                         printf("%s%s%s\n", set, xfrm_msg, reset);
 722                 /*
 723                  * we do not run diff between different kind
 724                  * of objects.
 725                  */
 726                 if ((one->mode ^ two->mode) & S_IFMT)
 727                         goto free_ab_and_return;
 728                 if (complete_rewrite) {
 729                         emit_rewrite_diff(name_a, name_b, one, two);
 730                         goto free_ab_and_return;
 731                 }
 732         }
 733
 734         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
 735                 die("unable to read files to diff");
 736
 737         if (!o->text && (mmfile_is_binary(&mf1) || mmfile_is_binary(&mf2))) {
 738                 /* Quite common confusing case */
 739                 if (mf1.size == mf2.size &&
 740                     !memcmp(mf1.ptr, mf2.ptr, mf1.size))
 741                         goto free_ab_and_return;
 742                 if (o->binary)
 743                         emit_binary_diff(&mf1, &mf2);
 744                 else
 745                         printf("Binary files %s and %s differ\n",
 746                                lbl[0], lbl[1]);
 747         }
 748         else {
 749                 /* Crazy xdl interfaces.. */
 750                 const char *diffopts = getenv("GIT_DIFF_OPTS");
 751                 xpparam_t xpp;
 752                 xdemitconf_t xecfg;
 753                 xdemitcb_t ecb;
 754                 struct emit_callback ecbdata;
 755
 756                 memset(&ecbdata, 0, sizeof(ecbdata));
 757                 ecbdata.label_path = lbl;
 758                 ecbdata.color_diff = o->color_diff;
 759                 xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
 760                 xecfg.ctxlen = o->context;
 761                 xecfg.flags = XDL_EMIT_FUNCNAMES;
 762                 if (!diffopts)
 763                         ;
 764                 else if (!strncmp(diffopts, "--unified=", 10))
 765                         xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
 766                 else if (!strncmp(diffopts, "-u", 2))
 767                         xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
 768                 ecb.outf = xdiff_outf;
 769                 ecb.priv = &ecbdata;
 770                 ecbdata.xm.consume = fn_out_consume;
 771                 xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
 772         }
 773
 774  free_ab_and_return:
 775         free(a_one);
 776         free(b_two);
 777         return;
 778 }
 779
 780 static void builtin_diffstat(const char *name_a, const char *name_b,
 781                              struct diff_filespec *one,
 782                              struct diff_filespec *two,
 783                              struct diffstat_t *diffstat,
 784                              struct diff_options *o,
 785                              int complete_rewrite)
 786 {
 787         mmfile_t mf1, mf2;
 788         struct diffstat_file *data;
 789
 790         data = diffstat_add(diffstat, name_a, name_b);
 791
 792         if (!one || !two) {
 793                 data->is_unmerged = 1;
 794                 return;
 795         }
 796         if (complete_rewrite) {
 797                 diff_populate_filespec(one, 0);
 798                 diff_populate_filespec(two, 0);
 799                 data->deleted = count_lines(one->data, one->size);
 800                 data->added = count_lines(two->data, two->size);
 801                 return;
 802         }
 803         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
 804                 die("unable to read files to diff");
 805
 806         if (mmfile_is_binary(&mf1) || mmfile_is_binary(&mf2))
 807                 data->is_binary = 1;
 808         else {
 809                 /* Crazy xdl interfaces.. */
 810                 xpparam_t xpp;
 811                 xdemitconf_t xecfg;
 812                 xdemitcb_t ecb;
 813
 814                 xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
 815                 xecfg.ctxlen = 0;
 816                 xecfg.flags = 0;
 817                 ecb.outf = xdiff_outf;
 818                 ecb.priv = diffstat;
 819                 xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
 820         }
 821 }
 822
 823 static void builtin_checkdiff(const char *name_a, const char *name_b,
 824                              struct diff_filespec *one,
 825                              struct diff_filespec *two)
 826 {
 827         mmfile_t mf1, mf2;
 828         struct checkdiff_t data;
 829
 830         if (!two)
 831                 return;
 832
 833         memset(&data, 0, sizeof(data));
 834         data.xm.consume = checkdiff_consume;
 835         data.filename = name_b ? name_b : name_a;
 836         data.lineno = 0;
 837
 838         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
 839                 die("unable to read files to diff");
 840
 841         if (mmfile_is_binary(&mf2))
 842                 return;
 843         else {
 844                 /* Crazy xdl interfaces.. */
 845                 xpparam_t xpp;
 846                 xdemitconf_t xecfg;
 847                 xdemitcb_t ecb;
 848
 849                 xpp.flags = XDF_NEED_MINIMAL;
 850                 xecfg.ctxlen = 0;
 851                 xecfg.flags = 0;
 852                 ecb.outf = xdiff_outf;
 853                 ecb.priv = &data;
 854                 xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
 855         }
 856 }
 857
 858 struct diff_filespec *alloc_filespec(const char *path)
 859 {
 860         int namelen = strlen(path);
 861         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
 862
 863         memset(spec, 0, sizeof(*spec));
 864         spec->path = (char *)(spec + 1);
 865         memcpy(spec->path, path, namelen+1);
 866         return spec;
 867 }
 868
 869 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
 870                    unsigned short mode)
 871 {
 872         if (mode) {
 873                 spec->mode = canon_mode(mode);
 874                 memcpy(spec->sha1, sha1, 20);
 875                 spec->sha1_valid = !!memcmp(sha1, null_sha1, 20);
 876         }
 877 }
 878
 879 /*
 880  * Given a name and sha1 pair, if the dircache tells us the file in
 881  * the work tree has that object contents, return true, so that
 882  * prepare_temp_file() does not have to inflate and extract.
 883  */
 884 static int work_tree_matches(const char *name, const unsigned char *sha1)
 885 {
 886         struct cache_entry *ce;
 887         struct stat st;
 888         int pos, len;
 889
 890         /* We do not read the cache ourselves here, because the
 891          * benchmark with my previous version that always reads cache
 892          * shows that it makes things worse for diff-tree comparing
 893          * two linux-2.6 kernel trees in an already checked out work
 894          * tree.  This is because most diff-tree comparisons deal with
 895          * only a small number of files, while reading the cache is
 896          * expensive for a large project, and its cost outweighs the
 897          * savings we get by not inflating the object to a temporary
 898          * file.  Practically, this code only helps when we are used
 899          * by diff-cache --cached, which does read the cache before
 900          * calling us.
 901          */
 902         if (!active_cache)
 903                 return 0;
 904
 905         len = strlen(name);
 906         pos = cache_name_pos(name, len);
 907         if (pos < 0)
 908                 return 0;
 909         ce = active_cache[pos];
 910         if ((lstat(name, &st) < 0) ||
 911             !S_ISREG(st.st_mode) || /* careful! */
 912             ce_match_stat(ce, &st, 0) ||
 913             memcmp(sha1, ce->sha1, 20))
 914                 return 0;
 915         /* we return 1 only when we can stat, it is a regular file,
 916          * stat information matches, and sha1 recorded in the cache
 917          * matches.  I.e. we know the file in the work tree really is
 918          * the same as the <name, sha1> pair.
 919          */
 920         return 1;
 921 }
 922
 923 static struct sha1_size_cache {
 924         unsigned char sha1[20];
 925         unsigned long size;
 926 } **sha1_size_cache;
 927 static int sha1_size_cache_nr, sha1_size_cache_alloc;
 928
 929 static struct sha1_size_cache *locate_size_cache(unsigned char *sha1,
 930                                                  int find_only,
 931                                                  unsigned long size)
 932 {
 933         int first, last;
 934         struct sha1_size_cache *e;
 935
 936         first = 0;
 937         last = sha1_size_cache_nr;
 938         while (last > first) {
 939                 int cmp, next = (last + first) >> 1;
 940                 e = sha1_size_cache[next];
 941                 cmp = memcmp(e->sha1, sha1, 20);
 942                 if (!cmp)
 943                         return e;
 944                 if (cmp < 0) {
 945                         last = next;
 946                         continue;
 947                 }
 948                 first = next+1;
 949         }
 950         /* not found */
 951         if (find_only)
 952                 return NULL;
 953         /* insert to make it at "first" */
 954         if (sha1_size_cache_alloc <= sha1_size_cache_nr) {
 955                 sha1_size_cache_alloc = alloc_nr(sha1_size_cache_alloc);
 956                 sha1_size_cache = xrealloc(sha1_size_cache,
 957                                            sha1_size_cache_alloc *
 958                                            sizeof(*sha1_size_cache));
 959         }
 960         sha1_size_cache_nr++;
 961         if (first < sha1_size_cache_nr)
 962                 memmove(sha1_size_cache + first + 1, sha1_size_cache + first,
 963                         (sha1_size_cache_nr - first - 1) *
 964                         sizeof(*sha1_size_cache));
 965         e = xmalloc(sizeof(struct sha1_size_cache));
 966         sha1_size_cache[first] = e;
 967         memcpy(e->sha1, sha1, 20);
 968         e->size = size;
 969         return e;
 970 }
 971
 972 /*
 973  * While doing rename detection and pickaxe operation, we may need to
 974  * grab the data for the blob (or file) for our own in-core comparison.
 975  * diff_filespec has data and size fields for this purpose.
 976  */
 977 int diff_populate_filespec(struct diff_filespec *s, int size_only)
 978 {
 979         int err = 0;
 980         if (!DIFF_FILE_VALID(s))
 981                 die("internal error: asking to populate invalid file.");
 982         if (S_ISDIR(s->mode))
 983                 return -1;
 984
 985         if (!use_size_cache)
 986                 size_only = 0;
 987
 988         if (s->data)
 989                 return err;
 990         if (!s->sha1_valid ||
 991             work_tree_matches(s->path, s->sha1)) {
 992                 struct stat st;
 993                 int fd;
 994                 if (lstat(s->path, &st) < 0) {
 995                         if (errno == ENOENT) {
 996                         err_empty:
 997                                 err = -1;
 998                         empty:
 999                                 s->data = (char *)"";
1000                                 s->size = 0;
1001                                 return err;
1002                         }
1003                 }
1004                 s->size = st.st_size;
1005                 if (!s->size)
1006                         goto empty;
1007                 if (size_only)
1008                         return 0;
1009                 if (S_ISLNK(st.st_mode)) {
1010                         int ret;
1011                         s->data = xmalloc(s->size);
1012                         s->should_free = 1;
1013                         ret = readlink(s->path, s->data, s->size);
1014                         if (ret < 0) {
1015                                 free(s->data);
1016                                 goto err_empty;
1017                         }
1018                         return 0;
1019                 }
1020                 fd = open(s->path, O_RDONLY);
1021                 if (fd < 0)
1022                         goto err_empty;
1023                 s->data = mmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
1024                 close(fd);
1025                 if (s->data == MAP_FAILED)
1026                         goto err_empty;
1027                 s->should_munmap = 1;
1028         }
1029         else {
1030                 char type[20];
1031                 struct sha1_size_cache *e;
1032
1033                 if (size_only) {
1034                         e = locate_size_cache(s->sha1, 1, 0);
1035                         if (e) {
1036                                 s->size = e->size;
1037                                 return 0;
1038                         }
1039                         if (!sha1_object_info(s->sha1, type, &s->size))
1040                                 locate_size_cache(s->sha1, 0, s->size);
1041                 }
1042                 else {
1043                         s->data = read_sha1_file(s->sha1, type, &s->size);
1044                         s->should_free = 1;
1045                 }
1046         }
1047         return 0;
1048 }
1049
1050 void diff_free_filespec_data(struct diff_filespec *s)
1051 {
1052         if (s->should_free)
1053                 free(s->data);
1054         else if (s->should_munmap)
1055                 munmap(s->data, s->size);
1056         s->should_free = s->should_munmap = 0;
1057         s->data = NULL;
1058         free(s->cnt_data);
1059         s->cnt_data = NULL;
1060 }
1061
1062 static void prep_temp_blob(struct diff_tempfile *temp,
1063                            void *blob,
1064                            unsigned long size,
1065                            const unsigned char *sha1,
1066                            int mode)
1067 {
1068         int fd;
1069
1070         fd = git_mkstemp(temp->tmp_path, TEMPFILE_PATH_LEN, ".diff_XXXXXX");
1071         if (fd < 0)
1072                 die("unable to create temp-file");
1073         if (write(fd, blob, size) != size)
1074                 die("unable to write temp-file");
1075         close(fd);
1076         temp->name = temp->tmp_path;
1077         strcpy(temp->hex, sha1_to_hex(sha1));
1078         temp->hex[40] = 0;
1079         sprintf(temp->mode, "%06o", mode);
1080 }
1081
1082 static void prepare_temp_file(const char *name,
1083                               struct diff_tempfile *temp,
1084                               struct diff_filespec *one)
1085 {
1086         if (!DIFF_FILE_VALID(one)) {
1087         not_a_valid_file:
1088                 /* A '-' entry produces this for file-2, and
1089                  * a '+' entry produces this for file-1.
1090                  */
1091                 temp->name = "/dev/null";
1092                 strcpy(temp->hex, ".");
1093                 strcpy(temp->mode, ".");
1094                 return;
1095         }
1096
1097         if (!one->sha1_valid ||
1098             work_tree_matches(name, one->sha1)) {
1099                 struct stat st;
1100                 if (lstat(name, &st) < 0) {
1101                         if (errno == ENOENT)
1102                                 goto not_a_valid_file;
1103                         die("stat(%s): %s", name, strerror(errno));
1104                 }
1105                 if (S_ISLNK(st.st_mode)) {
1106                         int ret;
1107                         char buf[PATH_MAX + 1]; /* ought to be SYMLINK_MAX */
1108                         if (sizeof(buf) <= st.st_size)
1109                                 die("symlink too long: %s", name);
1110                         ret = readlink(name, buf, st.st_size);
1111                         if (ret < 0)
1112                                 die("readlink(%s)", name);
1113                         prep_temp_blob(temp, buf, st.st_size,
1114                                        (one->sha1_valid ?
1115                                         one->sha1 : null_sha1),
1116                                        (one->sha1_valid ?
1117                                         one->mode : S_IFLNK));
1118                 }
1119                 else {
1120                         /* we can borrow from the file in the work tree */
1121                         temp->name = name;
1122                         if (!one->sha1_valid)
1123                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
1124                         else
1125                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
1126                         /* Even though we may sometimes borrow the
1127                          * contents from the work tree, we always want
1128                          * one->mode.  mode is trustworthy even when
1129                          * !(one->sha1_valid), as long as
1130                          * DIFF_FILE_VALID(one).
1131                          */
1132                         sprintf(temp->mode, "%06o", one->mode);
1133                 }
1134                 return;
1135         }
1136         else {
1137                 if (diff_populate_filespec(one, 0))
1138                         die("cannot read data blob for %s", one->path);
1139                 prep_temp_blob(temp, one->data, one->size,
1140                                one->sha1, one->mode);
1141         }
1142 }
1143
1144 static void remove_tempfile(void)
1145 {
1146         int i;
1147
1148         for (i = 0; i < 2; i++)
1149                 if (diff_temp[i].name == diff_temp[i].tmp_path) {
1150                         unlink(diff_temp[i].name);
1151                         diff_temp[i].name = NULL;
1152                 }
1153 }
1154
1155 static void remove_tempfile_on_signal(int signo)
1156 {
1157         remove_tempfile();
1158         signal(SIGINT, SIG_DFL);
1159         raise(signo);
1160 }
1161
1162 static int spawn_prog(const char *pgm, const char **arg)
1163 {
1164         pid_t pid;
1165         int status;
1166
1167         fflush(NULL);
1168         pid = fork();
1169         if (pid < 0)
1170                 die("unable to fork");
1171         if (!pid) {
1172                 execvp(pgm, (char *const*) arg);
1173                 exit(255);
1174         }
1175
1176         while (waitpid(pid, &status, 0) < 0) {
1177                 if (errno == EINTR)
1178                         continue;
1179                 return -1;
1180         }
1181
1182         /* Earlier we did not check the exit status because
1183          * diff exits non-zero if files are different, and
1184          * we are not interested in knowing that.  It was a
1185          * mistake which made it harder to quit a diff-*
1186          * session that uses the git-apply-patch-script as
1187          * the GIT_EXTERNAL_DIFF.  A custom GIT_EXTERNAL_DIFF
1188          * should also exit non-zero only when it wants to
1189          * abort the entire diff-* session.
1190          */
1191         if (WIFEXITED(status) && !WEXITSTATUS(status))
1192                 return 0;
1193         return -1;
1194 }
1195
1196 /* An external diff command takes:
1197  *
1198  * diff-cmd name infile1 infile1-sha1 infile1-mode \
1199  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
1200  *
1201  */
1202 static void run_external_diff(const char *pgm,
1203                               const char *name,
1204                               const char *other,
1205                               struct diff_filespec *one,
1206                               struct diff_filespec *two,
1207                               const char *xfrm_msg,
1208                               int complete_rewrite)
1209 {
1210         const char *spawn_arg[10];
1211         struct diff_tempfile *temp = diff_temp;
1212         int retval;
1213         static int atexit_asked = 0;
1214         const char *othername;
1215         const char **arg = &spawn_arg[0];
1216
1217         othername = (other? other : name);
1218         if (one && two) {
1219                 prepare_temp_file(name, &temp[0], one);
1220                 prepare_temp_file(othername, &temp[1], two);
1221                 if (! atexit_asked &&
1222                     (temp[0].name == temp[0].tmp_path ||
1223                      temp[1].name == temp[1].tmp_path)) {
1224                         atexit_asked = 1;
1225                         atexit(remove_tempfile);
1226                 }
1227                 signal(SIGINT, remove_tempfile_on_signal);
1228         }
1229
1230         if (one && two) {
1231                 *arg++ = pgm;
1232                 *arg++ = name;
1233                 *arg++ = temp[0].name;
1234                 *arg++ = temp[0].hex;
1235                 *arg++ = temp[0].mode;
1236                 *arg++ = temp[1].name;
1237                 *arg++ = temp[1].hex;
1238                 *arg++ = temp[1].mode;
1239                 if (other) {
1240                         *arg++ = other;
1241                         *arg++ = xfrm_msg;
1242                 }
1243         } else {
1244                 *arg++ = pgm;
1245                 *arg++ = name;
1246         }
1247         *arg = NULL;
1248         retval = spawn_prog(pgm, spawn_arg);
1249         remove_tempfile();
1250         if (retval) {
1251                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
1252                 exit(1);
1253         }
1254 }
1255
1256 static void run_diff_cmd(const char *pgm,
1257                          const char *name,
1258                          const char *other,
1259                          struct diff_filespec *one,
1260                          struct diff_filespec *two,
1261                          const char *xfrm_msg,
1262                          struct diff_options *o,
1263                          int complete_rewrite)
1264 {
1265         if (pgm) {
1266                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
1267                                   complete_rewrite);
1268                 return;
1269         }
1270         if (one && two)
1271                 builtin_diff(name, other ? other : name,
1272                              one, two, xfrm_msg, o, complete_rewrite);
1273         else
1274                 printf("* Unmerged path %s\n", name);
1275 }
1276
1277 static void diff_fill_sha1_info(struct diff_filespec *one)
1278 {
1279         if (DIFF_FILE_VALID(one)) {
1280                 if (!one->sha1_valid) {
1281                         struct stat st;
1282                         if (lstat(one->path, &st) < 0)
1283                                 die("stat %s", one->path);
1284                         if (index_path(one->sha1, one->path, &st, 0))
1285                                 die("cannot hash %s\n", one->path);
1286                 }
1287         }
1288         else
1289                 memset(one->sha1, 0, 20);
1290 }
1291
1292 static void run_diff(struct diff_filepair *p, struct diff_options *o)
1293 {
1294         const char *pgm = external_diff();
1295         char msg[PATH_MAX*2+300], *xfrm_msg;
1296         struct diff_filespec *one;
1297         struct diff_filespec *two;
1298         const char *name;
1299         const char *other;
1300         char *name_munged, *other_munged;
1301         int complete_rewrite = 0;
1302         int len;
1303
1304         if (DIFF_PAIR_UNMERGED(p)) {
1305                 /* unmerged */
1306                 run_diff_cmd(pgm, p->one->path, NULL, NULL, NULL, NULL, o, 0);
1307                 return;
1308         }
1309
1310         name = p->one->path;
1311         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
1312         name_munged = quote_one(name);
1313         other_munged = quote_one(other);
1314         one = p->one; two = p->two;
1315
1316         diff_fill_sha1_info(one);
1317         diff_fill_sha1_info(two);
1318
1319         len = 0;
1320         switch (p->status) {
1321         case DIFF_STATUS_COPIED:
1322                 len += snprintf(msg + len, sizeof(msg) - len,
1323                                 "similarity index %d%%\n"
1324                                 "copy from %s\n"
1325                                 "copy to %s\n",
1326                                 (int)(0.5 + p->score * 100.0/MAX_SCORE),
1327                                 name_munged, other_munged);
1328                 break;
1329         case DIFF_STATUS_RENAMED:
1330                 len += snprintf(msg + len, sizeof(msg) - len,
1331                                 "similarity index %d%%\n"
1332                                 "rename from %s\n"
1333                                 "rename to %s\n",
1334                                 (int)(0.5 + p->score * 100.0/MAX_SCORE),
1335                                 name_munged, other_munged);
1336                 break;
1337         case DIFF_STATUS_MODIFIED:
1338                 if (p->score) {
1339                         len += snprintf(msg + len, sizeof(msg) - len,
1340                                         "dissimilarity index %d%%\n",
1341                                         (int)(0.5 + p->score *
1342                                               100.0/MAX_SCORE));
1343                         complete_rewrite = 1;
1344                         break;
1345                 }
1346                 /* fallthru */
1347         default:
1348                 /* nothing */
1349                 ;
1350         }
1351
1352         if (memcmp(one->sha1, two->sha1, 20)) {
1353                 int abbrev = o->full_index ? 40 : DEFAULT_ABBREV;
1354
1355                 len += snprintf(msg + len, sizeof(msg) - len,
1356                                 "index %.*s..%.*s",
1357                                 abbrev, sha1_to_hex(one->sha1),
1358                                 abbrev, sha1_to_hex(two->sha1));
1359                 if (one->mode == two->mode)
1360                         len += snprintf(msg + len, sizeof(msg) - len,
1361                                         " %06o", one->mode);
1362                 len += snprintf(msg + len, sizeof(msg) - len, "\n");
1363         }
1364
1365         if (len)
1366                 msg[--len] = 0;
1367         xfrm_msg = len ? msg : NULL;
1368
1369         if (!pgm &&
1370             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
1371             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
1372                 /* a filepair that changes between file and symlink
1373                  * needs to be split into deletion and creation.
1374                  */
1375                 struct diff_filespec *null = alloc_filespec(two->path);
1376                 run_diff_cmd(NULL, name, other, one, null, xfrm_msg, o, 0);
1377                 free(null);
1378                 null = alloc_filespec(one->path);
1379                 run_diff_cmd(NULL, name, other, null, two, xfrm_msg, o, 0);
1380                 free(null);
1381         }
1382         else
1383                 run_diff_cmd(pgm, name, other, one, two, xfrm_msg, o,
1384                              complete_rewrite);
1385
1386         free(name_munged);
1387         free(other_munged);
1388 }
1389
1390 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
1391                          struct diffstat_t *diffstat)
1392 {
1393         const char *name;
1394         const char *other;
1395         int complete_rewrite = 0;
1396
1397         if (DIFF_PAIR_UNMERGED(p)) {
1398                 /* unmerged */
1399                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, 0);
1400                 return;
1401         }
1402
1403         name = p->one->path;
1404         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
1405
1406         diff_fill_sha1_info(p->one);
1407         diff_fill_sha1_info(p->two);
1408
1409         if (p->status == DIFF_STATUS_MODIFIED && p->score)
1410                 complete_rewrite = 1;
1411         builtin_diffstat(name, other, p->one, p->two, diffstat, o, complete_rewrite);
1412 }
1413
1414 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
1415 {
1416         const char *name;
1417         const char *other;
1418
1419         if (DIFF_PAIR_UNMERGED(p)) {
1420                 /* unmerged */
1421                 return;
1422         }
1423
1424         name = p->one->path;
1425         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
1426
1427         diff_fill_sha1_info(p->one);
1428         diff_fill_sha1_info(p->two);
1429
1430         builtin_checkdiff(name, other, p->one, p->two);
1431 }
1432
1433 void diff_setup(struct diff_options *options)
1434 {
1435         memset(options, 0, sizeof(*options));
1436         options->line_termination = '\n';
1437         options->break_opt = -1;
1438         options->rename_limit = -1;
1439         options->context = 3;
1440         options->msg_sep = "";
1441
1442         options->change = diff_change;
1443         options->add_remove = diff_addremove;
1444         options->color_diff = diff_use_color_default;
1445         options->detect_rename = diff_detect_rename_default;
1446 }
1447
1448 int diff_setup_done(struct diff_options *options)
1449 {
1450         if ((options->find_copies_harder &&
1451              options->detect_rename != DIFF_DETECT_COPY) ||
1452             (0 <= options->rename_limit && !options->detect_rename))
1453                 return -1;
1454
1455         if (options->output_format & (DIFF_FORMAT_NAME |
1456                                       DIFF_FORMAT_NAME_STATUS |
1457                                       DIFF_FORMAT_CHECKDIFF |
1458                                       DIFF_FORMAT_NO_OUTPUT))
1459                 options->output_format &= ~(DIFF_FORMAT_RAW |
1460                                             DIFF_FORMAT_DIFFSTAT |
1461                                             DIFF_FORMAT_SUMMARY |
1462                                             DIFF_FORMAT_PATCH);
1463
1464         /*
1465          * These cases always need recursive; we do not drop caller-supplied
1466          * recursive bits for other formats here.
1467          */
1468         if (options->output_format & (DIFF_FORMAT_PATCH |
1469                                       DIFF_FORMAT_DIFFSTAT |
1470                                       DIFF_FORMAT_CHECKDIFF))
1471                 options->recursive = 1;
1472         /*
1473          * Also pickaxe would not work very well if you do not say recursive
1474          */
1475         if (options->pickaxe)
1476                 options->recursive = 1;
1477
1478         if (options->detect_rename && options->rename_limit < 0)
1479                 options->rename_limit = diff_rename_limit_default;
1480         if (options->setup & DIFF_SETUP_USE_CACHE) {
1481                 if (!active_cache)
1482                         /* read-cache does not die even when it fails
1483                          * so it is safe for us to do this here.  Also
1484                          * it does not smudge active_cache or active_nr
1485                          * when it fails, so we do not have to worry about
1486                          * cleaning it up ourselves either.
1487                          */
1488                         read_cache();
1489         }
1490         if (options->setup & DIFF_SETUP_USE_SIZE_CACHE)
1491                 use_size_cache = 1;
1492         if (options->abbrev <= 0 || 40 < options->abbrev)
1493                 options->abbrev = 40; /* full */
1494
1495         return 0;
1496 }
1497
1498 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
1499 {
1500         char c, *eq;
1501         int len;
1502
1503         if (*arg != '-')
1504                 return 0;
1505         c = *++arg;
1506         if (!c)
1507                 return 0;
1508         if (c == arg_short) {
1509                 c = *++arg;
1510                 if (!c)
1511                         return 1;
1512                 if (val && isdigit(c)) {
1513                         char *end;
1514                         int n = strtoul(arg, &end, 10);
1515                         if (*end)
1516                                 return 0;
1517                         *val = n;
1518                         return 1;
1519                 }
1520                 return 0;
1521         }
1522         if (c != '-')
1523                 return 0;
1524         arg++;
1525         eq = strchr(arg, '=');
1526         if (eq)
1527                 len = eq - arg;
1528         else
1529                 len = strlen(arg);
1530         if (!len || strncmp(arg, arg_long, len))
1531                 return 0;
1532         if (eq) {
1533                 int n;
1534                 char *end;
1535                 if (!isdigit(*++eq))
1536                         return 0;
1537                 n = strtoul(eq, &end, 10);
1538                 if (*end)
1539                         return 0;
1540                 *val = n;
1541         }
1542         return 1;
1543 }
1544
1545 int diff_opt_parse(struct diff_options *options, const char **av, int ac)
1546 {
1547         const char *arg = av[0];
1548         if (!strcmp(arg, "-p") || !strcmp(arg, "-u"))
1549                 options->output_format |= DIFF_FORMAT_PATCH;
1550         else if (opt_arg(arg, 'U', "unified", &options->context))
1551                 options->output_format |= DIFF_FORMAT_PATCH;
1552         else if (!strcmp(arg, "--raw"))
1553                 options->output_format |= DIFF_FORMAT_RAW;
1554         else if (!strcmp(arg, "--patch-with-raw")) {
1555                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
1556         }
1557         else if (!strcmp(arg, "--stat"))
1558                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
1559         else if (!strcmp(arg, "--check"))
1560                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
1561         else if (!strcmp(arg, "--summary"))
1562                 options->output_format |= DIFF_FORMAT_SUMMARY;
1563         else if (!strcmp(arg, "--patch-with-stat")) {
1564                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
1565         }
1566         else if (!strcmp(arg, "-z"))
1567                 options->line_termination = 0;
1568         else if (!strncmp(arg, "-l", 2))
1569                 options->rename_limit = strtoul(arg+2, NULL, 10);
1570         else if (!strcmp(arg, "--full-index"))
1571                 options->full_index = 1;
1572         else if (!strcmp(arg, "--binary")) {
1573                 options->output_format |= DIFF_FORMAT_PATCH;
1574                 options->full_index = options->binary = 1;
1575         }
1576         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text")) {
1577                 options->text = 1;
1578         }
1579         else if (!strcmp(arg, "--name-only"))
1580                 options->output_format |= DIFF_FORMAT_NAME;
1581         else if (!strcmp(arg, "--name-status"))
1582                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
1583         else if (!strcmp(arg, "-R"))
1584                 options->reverse_diff = 1;
1585         else if (!strncmp(arg, "-S", 2))
1586                 options->pickaxe = arg + 2;
1587         else if (!strcmp(arg, "-s")) {
1588                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
1589         }
1590         else if (!strncmp(arg, "-O", 2))
1591                 options->orderfile = arg + 2;
1592         else if (!strncmp(arg, "--diff-filter=", 14))
1593                 options->filter = arg + 14;
1594         else if (!strcmp(arg, "--pickaxe-all"))
1595                 options->pickaxe_opts = DIFF_PICKAXE_ALL;
1596         else if (!strcmp(arg, "--pickaxe-regex"))
1597                 options->pickaxe_opts = DIFF_PICKAXE_REGEX;
1598         else if (!strncmp(arg, "-B", 2)) {
1599                 if ((options->break_opt =
1600                      diff_scoreopt_parse(arg)) == -1)
1601                         return -1;
1602         }
1603         else if (!strncmp(arg, "-M", 2)) {
1604                 if ((options->rename_score =
1605                      diff_scoreopt_parse(arg)) == -1)
1606                         return -1;
1607                 options->detect_rename = DIFF_DETECT_RENAME;
1608         }
1609         else if (!strncmp(arg, "-C", 2)) {
1610                 if ((options->rename_score =
1611                      diff_scoreopt_parse(arg)) == -1)
1612                         return -1;
1613                 options->detect_rename = DIFF_DETECT_COPY;
1614         }
1615         else if (!strcmp(arg, "--find-copies-harder"))
1616                 options->find_copies_harder = 1;
1617         else if (!strcmp(arg, "--abbrev"))
1618                 options->abbrev = DEFAULT_ABBREV;
1619         else if (!strncmp(arg, "--abbrev=", 9)) {
1620                 options->abbrev = strtoul(arg + 9, NULL, 10);
1621                 if (options->abbrev < MINIMUM_ABBREV)
1622                         options->abbrev = MINIMUM_ABBREV;
1623                 else if (40 < options->abbrev)
1624                         options->abbrev = 40;
1625         }
1626         else if (!strcmp(arg, "--color"))
1627                 options->color_diff = 1;
1628         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
1629                 options->xdl_opts |= XDF_IGNORE_WHITESPACE;
1630         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
1631                 options->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
1632         else if (!strcmp(arg, "--no-renames"))
1633                 options->detect_rename = 0;
1634         else
1635                 return 0;
1636         return 1;
1637 }
1638
1639 static int parse_num(const char **cp_p)
1640 {
1641         unsigned long num, scale;
1642         int ch, dot;
1643         const char *cp = *cp_p;
1644
1645         num = 0;
1646         scale = 1;
1647         dot = 0;
1648         for(;;) {
1649                 ch = *cp;
1650                 if ( !dot && ch == '.' ) {
1651                         scale = 1;
1652                         dot = 1;
1653                 } else if ( ch == '%' ) {
1654                         scale = dot ? scale*100 : 100;
1655                         cp++;   /* % is always at the end */
1656                         break;
1657                 } else if ( ch >= '0' && ch <= '9' ) {
1658                         if ( scale < 100000 ) {
1659                                 scale *= 10;
1660                                 num = (num*10) + (ch-'0');
1661                         }
1662                 } else {
1663                         break;
1664                 }
1665                 cp++;
1666         }
1667         *cp_p = cp;
1668
1669         /* user says num divided by scale and we say internally that
1670          * is MAX_SCORE * num / scale.
1671          */
1672         return (num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale);
1673 }
1674
1675 int diff_scoreopt_parse(const char *opt)
1676 {
1677         int opt1, opt2, cmd;
1678
1679         if (*opt++ != '-')
1680                 return -1;
1681         cmd = *opt++;
1682         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
1683                 return -1; /* that is not a -M, -C nor -B option */
1684
1685         opt1 = parse_num(&opt);
1686         if (cmd != 'B')
1687                 opt2 = 0;
1688         else {
1689                 if (*opt == 0)
1690                         opt2 = 0;
1691                 else if (*opt != '/')
1692                         return -1; /* we expect -B80/99 or -B80 */
1693                 else {
1694                         opt++;
1695                         opt2 = parse_num(&opt);
1696                 }
1697         }
1698         if (*opt != 0)
1699                 return -1;
1700         return opt1 | (opt2 << 16);
1701 }
1702
1703 struct diff_queue_struct diff_queued_diff;
1704
1705 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
1706 {
1707         if (queue->alloc <= queue->nr) {
1708                 queue->alloc = alloc_nr(queue->alloc);
1709                 queue->queue = xrealloc(queue->queue,
1710                                         sizeof(dp) * queue->alloc);
1711         }
1712         queue->queue[queue->nr++] = dp;
1713 }
1714
1715 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
1716                                  struct diff_filespec *one,
1717                                  struct diff_filespec *two)
1718 {
1719         struct diff_filepair *dp = xmalloc(sizeof(*dp));
1720         dp->one = one;
1721         dp->two = two;
1722         dp->score = 0;
1723         dp->status = 0;
1724         dp->source_stays = 0;
1725         dp->broken_pair = 0;
1726         if (queue)
1727                 diff_q(queue, dp);
1728         return dp;
1729 }
1730
1731 void diff_free_filepair(struct diff_filepair *p)
1732 {
1733         diff_free_filespec_data(p->one);
1734         diff_free_filespec_data(p->two);
1735         free(p->one);
1736         free(p->two);
1737         free(p);
1738 }
1739
1740 /* This is different from find_unique_abbrev() in that
1741  * it stuffs the result with dots for alignment.
1742  */
1743 const char *diff_unique_abbrev(const unsigned char *sha1, int len)
1744 {
1745         int abblen;
1746         const char *abbrev;
1747         if (len == 40)
1748                 return sha1_to_hex(sha1);
1749
1750         abbrev = find_unique_abbrev(sha1, len);
1751         if (!abbrev)
1752                 return sha1_to_hex(sha1);
1753         abblen = strlen(abbrev);
1754         if (abblen < 37) {
1755                 static char hex[41];
1756                 if (len < abblen && abblen <= len + 2)
1757                         sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
1758                 else
1759                         sprintf(hex, "%s...", abbrev);
1760                 return hex;
1761         }
1762         return sha1_to_hex(sha1);
1763 }
1764
1765 static void diff_flush_raw(struct diff_filepair *p,
1766                            struct diff_options *options)
1767 {
1768         int two_paths;
1769         char status[10];
1770         int abbrev = options->abbrev;
1771         const char *path_one, *path_two;
1772         int inter_name_termination = '\t';
1773         int line_termination = options->line_termination;
1774
1775         if (!line_termination)
1776                 inter_name_termination = 0;
1777
1778         path_one = p->one->path;
1779         path_two = p->two->path;
1780         if (line_termination) {
1781                 path_one = quote_one(path_one);
1782                 path_two = quote_one(path_two);
1783         }
1784
1785         if (p->score)
1786                 sprintf(status, "%c%03d", p->status,
1787                         (int)(0.5 + p->score * 100.0/MAX_SCORE));
1788         else {
1789                 status[0] = p->status;
1790                 status[1] = 0;
1791         }
1792         switch (p->status) {
1793         case DIFF_STATUS_COPIED:
1794         case DIFF_STATUS_RENAMED:
1795                 two_paths = 1;
1796                 break;
1797         case DIFF_STATUS_ADDED:
1798         case DIFF_STATUS_DELETED:
1799                 two_paths = 0;
1800                 break;
1801         default:
1802                 two_paths = 0;
1803                 break;
1804         }
1805         if (!(options->output_format & DIFF_FORMAT_NAME_STATUS)) {
1806                 printf(":%06o %06o %s ",
1807                        p->one->mode, p->two->mode,
1808                        diff_unique_abbrev(p->one->sha1, abbrev));
1809                 printf("%s ",
1810                        diff_unique_abbrev(p->two->sha1, abbrev));
1811         }
1812         printf("%s%c%s", status, inter_name_termination, path_one);
1813         if (two_paths)
1814                 printf("%c%s", inter_name_termination, path_two);
1815         putchar(line_termination);
1816         if (path_one != p->one->path)
1817                 free((void*)path_one);
1818         if (path_two != p->two->path)
1819                 free((void*)path_two);
1820 }
1821
1822 static void diff_flush_name(struct diff_filepair *p, int line_termination)
1823 {
1824         char *path = p->two->path;
1825
1826         if (line_termination)
1827                 path = quote_one(p->two->path);
1828         printf("%s%c", path, line_termination);
1829         if (p->two->path != path)
1830                 free(path);
1831 }
1832
1833 int diff_unmodified_pair(struct diff_filepair *p)
1834 {
1835         /* This function is written stricter than necessary to support
1836          * the currently implemented transformers, but the idea is to
1837          * let transformers to produce diff_filepairs any way they want,
1838          * and filter and clean them up here before producing the output.
1839          */
1840         struct diff_filespec *one, *two;
1841
1842         if (DIFF_PAIR_UNMERGED(p))
1843                 return 0; /* unmerged is interesting */
1844
1845         one = p->one;
1846         two = p->two;
1847
1848         /* deletion, addition, mode or type change
1849          * and rename are all interesting.
1850          */
1851         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
1852             DIFF_PAIR_MODE_CHANGED(p) ||
1853             strcmp(one->path, two->path))
1854                 return 0;
1855
1856         /* both are valid and point at the same path.  that is, we are
1857          * dealing with a change.
1858          */
1859         if (one->sha1_valid && two->sha1_valid &&
1860             !memcmp(one->sha1, two->sha1, sizeof(one->sha1)))
1861                 return 1; /* no change */
1862         if (!one->sha1_valid && !two->sha1_valid)
1863                 return 1; /* both look at the same file on the filesystem. */
1864         return 0;
1865 }
1866
1867 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
1868 {
1869         if (diff_unmodified_pair(p))
1870                 return;
1871
1872         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
1873             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
1874                 return; /* no tree diffs in patch format */
1875
1876         run_diff(p, o);
1877 }
1878
1879 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
1880                             struct diffstat_t *diffstat)
1881 {
1882         if (diff_unmodified_pair(p))
1883                 return;
1884
1885         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
1886             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
1887                 return; /* no tree diffs in patch format */
1888
1889         run_diffstat(p, o, diffstat);
1890 }
1891
1892 static void diff_flush_checkdiff(struct diff_filepair *p,
1893                 struct diff_options *o)
1894 {
1895         if (diff_unmodified_pair(p))
1896                 return;
1897
1898         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
1899             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
1900                 return; /* no tree diffs in patch format */
1901
1902         run_checkdiff(p, o);
1903 }
1904
1905 int diff_queue_is_empty(void)
1906 {
1907         struct diff_queue_struct *q = &diff_queued_diff;
1908         int i;
1909         for (i = 0; i < q->nr; i++)
1910                 if (!diff_unmodified_pair(q->queue[i]))
1911                         return 0;
1912         return 1;
1913 }
1914
1915 #if DIFF_DEBUG
1916 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
1917 {
1918         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
1919                 x, one ? one : "",
1920                 s->path,
1921                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
1922                 s->mode,
1923                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
1924         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
1925                 x, one ? one : "",
1926                 s->size, s->xfrm_flags);
1927 }
1928
1929 void diff_debug_filepair(const struct diff_filepair *p, int i)
1930 {
1931         diff_debug_filespec(p->one, i, "one");
1932         diff_debug_filespec(p->two, i, "two");
1933         fprintf(stderr, "score %d, status %c stays %d broken %d\n",
1934                 p->score, p->status ? p->status : '?',
1935                 p->source_stays, p->broken_pair);
1936 }
1937
1938 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
1939 {
1940         int i;
1941         if (msg)
1942                 fprintf(stderr, "%s\n", msg);
1943         fprintf(stderr, "q->nr = %d\n", q->nr);
1944         for (i = 0; i < q->nr; i++) {
1945                 struct diff_filepair *p = q->queue[i];
1946                 diff_debug_filepair(p, i);
1947         }
1948 }
1949 #endif
1950
1951 static void diff_resolve_rename_copy(void)
1952 {
1953         int i, j;
1954         struct diff_filepair *p, *pp;
1955         struct diff_queue_struct *q = &diff_queued_diff;
1956
1957         diff_debug_queue("resolve-rename-copy", q);
1958
1959         for (i = 0; i < q->nr; i++) {
1960                 p = q->queue[i];
1961                 p->status = 0; /* undecided */
1962                 if (DIFF_PAIR_UNMERGED(p))
1963                         p->status = DIFF_STATUS_UNMERGED;
1964                 else if (!DIFF_FILE_VALID(p->one))
1965                         p->status = DIFF_STATUS_ADDED;
1966                 else if (!DIFF_FILE_VALID(p->two))
1967                         p->status = DIFF_STATUS_DELETED;
1968                 else if (DIFF_PAIR_TYPE_CHANGED(p))
1969                         p->status = DIFF_STATUS_TYPE_CHANGED;
1970
1971                 /* from this point on, we are dealing with a pair
1972                  * whose both sides are valid and of the same type, i.e.
1973                  * either in-place edit or rename/copy edit.
1974                  */
1975                 else if (DIFF_PAIR_RENAME(p)) {
1976                         if (p->source_stays) {
1977                                 p->status = DIFF_STATUS_COPIED;
1978                                 continue;
1979                         }
1980                         /* See if there is some other filepair that
1981                          * copies from the same source as us.  If so
1982                          * we are a copy.  Otherwise we are either a
1983                          * copy if the path stays, or a rename if it
1984                          * does not, but we already handled "stays" case.
1985                          */
1986                         for (j = i + 1; j < q->nr; j++) {
1987                                 pp = q->queue[j];
1988                                 if (strcmp(pp->one->path, p->one->path))
1989                                         continue; /* not us */
1990                                 if (!DIFF_PAIR_RENAME(pp))
1991                                         continue; /* not a rename/copy */
1992                                 /* pp is a rename/copy from the same source */
1993                                 p->status = DIFF_STATUS_COPIED;
1994                                 break;
1995                         }
1996                         if (!p->status)
1997                                 p->status = DIFF_STATUS_RENAMED;
1998                 }
1999                 else if (memcmp(p->one->sha1, p->two->sha1, 20) ||
2000                          p->one->mode != p->two->mode)
2001                         p->status = DIFF_STATUS_MODIFIED;
2002                 else {
2003                         /* This is a "no-change" entry and should not
2004                          * happen anymore, but prepare for broken callers.
2005                          */
2006                         error("feeding unmodified %s to diffcore",
2007                               p->one->path);
2008                         p->status = DIFF_STATUS_UNKNOWN;
2009                 }
2010         }
2011         diff_debug_queue("resolve-rename-copy done", q);
2012 }
2013
2014 static int check_pair_status(struct diff_filepair *p)
2015 {
2016         switch (p->status) {
2017         case DIFF_STATUS_UNKNOWN:
2018                 return 0;
2019         case 0:
2020                 die("internal error in diff-resolve-rename-copy");
2021         default:
2022                 return 1;
2023         }
2024 }
2025
2026 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
2027 {
2028         int fmt = opt->output_format;
2029
2030         if (fmt & DIFF_FORMAT_CHECKDIFF)
2031                 diff_flush_checkdiff(p, opt);
2032         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
2033                 diff_flush_raw(p, opt);
2034         else if (fmt & DIFF_FORMAT_NAME)
2035                 diff_flush_name(p, opt->line_termination);
2036 }
2037
2038 static void show_file_mode_name(const char *newdelete, struct diff_filespec *fs)
2039 {
2040         if (fs->mode)
2041                 printf(" %s mode %06o %s\n", newdelete, fs->mode, fs->path);
2042         else
2043                 printf(" %s %s\n", newdelete, fs->path);
2044 }
2045
2046
2047 static void show_mode_change(struct diff_filepair *p, int show_name)
2048 {
2049         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
2050                 if (show_name)
2051                         printf(" mode change %06o => %06o %s\n",
2052                                p->one->mode, p->two->mode, p->two->path);
2053                 else
2054                         printf(" mode change %06o => %06o\n",
2055                                p->one->mode, p->two->mode);
2056         }
2057 }
2058
2059 static void show_rename_copy(const char *renamecopy, struct diff_filepair *p)
2060 {
2061         const char *old, *new;
2062
2063         /* Find common prefix */
2064         old = p->one->path;
2065         new = p->two->path;
2066         while (1) {
2067                 const char *slash_old, *slash_new;
2068                 slash_old = strchr(old, '/');
2069                 slash_new = strchr(new, '/');
2070                 if (!slash_old ||
2071                     !slash_new ||
2072                     slash_old - old != slash_new - new ||
2073                     memcmp(old, new, slash_new - new))
2074                         break;
2075                 old = slash_old + 1;
2076                 new = slash_new + 1;
2077         }
2078         /* p->one->path thru old is the common prefix, and old and new
2079          * through the end of names are renames
2080          */
2081         if (old != p->one->path)
2082                 printf(" %s %.*s{%s => %s} (%d%%)\n", renamecopy,
2083                        (int)(old - p->one->path), p->one->path,
2084                        old, new, (int)(0.5 + p->score * 100.0/MAX_SCORE));
2085         else
2086                 printf(" %s %s => %s (%d%%)\n", renamecopy,
2087                        p->one->path, p->two->path,
2088                        (int)(0.5 + p->score * 100.0/MAX_SCORE));
2089         show_mode_change(p, 0);
2090 }
2091
2092 static void diff_summary(struct diff_filepair *p)
2093 {
2094         switch(p->status) {
2095         case DIFF_STATUS_DELETED:
2096                 show_file_mode_name("delete", p->one);
2097                 break;
2098         case DIFF_STATUS_ADDED:
2099                 show_file_mode_name("create", p->two);
2100                 break;
2101         case DIFF_STATUS_COPIED:
2102                 show_rename_copy("copy", p);
2103                 break;
2104         case DIFF_STATUS_RENAMED:
2105                 show_rename_copy("rename", p);
2106                 break;
2107         default:
2108                 if (p->score) {
2109                         printf(" rewrite %s (%d%%)\n", p->two->path,
2110                                 (int)(0.5 + p->score * 100.0/MAX_SCORE));
2111                         show_mode_change(p, 0);
2112                 } else  show_mode_change(p, 1);
2113                 break;
2114         }
2115 }
2116
2117 struct patch_id_t {
2118         struct xdiff_emit_state xm;
2119         SHA_CTX *ctx;
2120         int patchlen;
2121 };
2122
2123 static int remove_space(char *line, int len)
2124 {
2125         int i;
2126         char *dst = line;
2127         unsigned char c;
2128
2129         for (i = 0; i < len; i++)
2130                 if (!isspace((c = line[i])))
2131                         *dst++ = c;
2132
2133         return dst - line;
2134 }
2135
2136 static void patch_id_consume(void *priv, char *line, unsigned long len)
2137 {
2138         struct patch_id_t *data = priv;
2139         int new_len;
2140
2141         /* Ignore line numbers when computing the SHA1 of the patch */
2142         if (!strncmp(line, "@@ -", 4))
2143                 return;
2144
2145         new_len = remove_space(line, len);
2146
2147         SHA1_Update(data->ctx, line, new_len);
2148         data->patchlen += new_len;
2149 }
2150
2151 /* returns 0 upon success, and writes result into sha1 */
2152 static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
2153 {
2154         struct diff_queue_struct *q = &diff_queued_diff;
2155         int i;
2156         SHA_CTX ctx;
2157         struct patch_id_t data;
2158         char buffer[PATH_MAX * 4 + 20];
2159
2160         SHA1_Init(&ctx);
2161         memset(&data, 0, sizeof(struct patch_id_t));
2162         data.ctx = &ctx;
2163         data.xm.consume = patch_id_consume;
2164
2165         for (i = 0; i < q->nr; i++) {
2166                 xpparam_t xpp;
2167                 xdemitconf_t xecfg;
2168                 xdemitcb_t ecb;
2169                 mmfile_t mf1, mf2;
2170                 struct diff_filepair *p = q->queue[i];
2171                 int len1, len2;
2172
2173                 if (p->status == 0)
2174                         return error("internal diff status error");
2175                 if (p->status == DIFF_STATUS_UNKNOWN)
2176                         continue;
2177                 if (diff_unmodified_pair(p))
2178                         continue;
2179                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2180                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2181                         continue;
2182                 if (DIFF_PAIR_UNMERGED(p))
2183                         continue;
2184
2185                 diff_fill_sha1_info(p->one);
2186                 diff_fill_sha1_info(p->two);
2187                 if (fill_mmfile(&mf1, p->one) < 0 ||
2188                                 fill_mmfile(&mf2, p->two) < 0)
2189                         return error("unable to read files to diff");
2190
2191                 /* Maybe hash p->two? into the patch id? */
2192                 if (mmfile_is_binary(&mf2))
2193                         continue;
2194
2195                 len1 = remove_space(p->one->path, strlen(p->one->path));
2196                 len2 = remove_space(p->two->path, strlen(p->two->path));
2197                 if (p->one->mode == 0)
2198                         len1 = snprintf(buffer, sizeof(buffer),
2199                                         "diff--gita/%.*sb/%.*s"
2200                                         "newfilemode%06o"
2201                                         "---/dev/null"
2202                                         "+++b/%.*s",
2203                                         len1, p->one->path,
2204                                         len2, p->two->path,
2205                                         p->two->mode,
2206                                         len2, p->two->path);
2207                 else if (p->two->mode == 0)
2208                         len1 = snprintf(buffer, sizeof(buffer),
2209                                         "diff--gita/%.*sb/%.*s"
2210                                         "deletedfilemode%06o"
2211                                         "---a/%.*s"
2212                                         "+++/dev/null",
2213                                         len1, p->one->path,
2214                                         len2, p->two->path,
2215                                         p->one->mode,
2216                                         len1, p->one->path);
2217                 else
2218                         len1 = snprintf(buffer, sizeof(buffer),
2219                                         "diff--gita/%.*sb/%.*s"
2220                                         "---a/%.*s"
2221                                         "+++b/%.*s",
2222                                         len1, p->one->path,
2223                                         len2, p->two->path,
2224                                         len1, p->one->path,
2225                                         len2, p->two->path);
2226                 SHA1_Update(&ctx, buffer, len1);
2227
2228                 xpp.flags = XDF_NEED_MINIMAL;
2229                 xecfg.ctxlen = 3;
2230                 xecfg.flags = XDL_EMIT_FUNCNAMES;
2231                 ecb.outf = xdiff_outf;
2232                 ecb.priv = &data;
2233                 xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
2234         }
2235
2236         SHA1_Final(sha1, &ctx);
2237         return 0;
2238 }
2239
2240 int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
2241 {
2242         struct diff_queue_struct *q = &diff_queued_diff;
2243         int i;
2244         int result = diff_get_patch_id(options, sha1);
2245
2246         for (i = 0; i < q->nr; i++)
2247                 diff_free_filepair(q->queue[i]);
2248
2249         free(q->queue);
2250         q->queue = NULL;
2251         q->nr = q->alloc = 0;
2252
2253         return result;
2254 }
2255
2256 static int is_summary_empty(const struct diff_queue_struct *q)
2257 {
2258         int i;
2259
2260         for (i = 0; i < q->nr; i++) {
2261                 const struct diff_filepair *p = q->queue[i];
2262
2263                 switch (p->status) {
2264                 case DIFF_STATUS_DELETED:
2265                 case DIFF_STATUS_ADDED:
2266                 case DIFF_STATUS_COPIED:
2267                 case DIFF_STATUS_RENAMED:
2268                         return 0;
2269                 default:
2270                         if (p->score)
2271                                 return 0;
2272                         if (p->one->mode && p->two->mode &&
2273                             p->one->mode != p->two->mode)
2274                                 return 0;
2275                         break;
2276                 }
2277         }
2278         return 1;
2279 }
2280
2281 void diff_flush(struct diff_options *options)
2282 {
2283         struct diff_queue_struct *q = &diff_queued_diff;
2284         int i, output_format = options->output_format;
2285         int separator = 0;
2286
2287         /*
2288          * Order: raw, stat, summary, patch
2289          * or:    name/name-status/checkdiff (other bits clear)
2290          */
2291         if (!q->nr)
2292                 goto free_queue;
2293
2294         if (output_format & (DIFF_FORMAT_RAW |
2295                              DIFF_FORMAT_NAME |
2296                              DIFF_FORMAT_NAME_STATUS |
2297                              DIFF_FORMAT_CHECKDIFF)) {
2298                 for (i = 0; i < q->nr; i++) {
2299                         struct diff_filepair *p = q->queue[i];
2300                         if (check_pair_status(p))
2301                                 flush_one_pair(p, options);
2302                 }
2303                 separator++;
2304         }
2305
2306         if (output_format & DIFF_FORMAT_DIFFSTAT) {
2307                 struct diffstat_t diffstat;
2308
2309                 memset(&diffstat, 0, sizeof(struct diffstat_t));
2310                 diffstat.xm.consume = diffstat_consume;
2311                 for (i = 0; i < q->nr; i++) {
2312                         struct diff_filepair *p = q->queue[i];
2313                         if (check_pair_status(p))
2314                                 diff_flush_stat(p, options, &diffstat);
2315                 }
2316                 show_stats(&diffstat);
2317                 separator++;
2318         }
2319
2320         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
2321                 for (i = 0; i < q->nr; i++)
2322                         diff_summary(q->queue[i]);
2323                 separator++;
2324         }
2325
2326         if (output_format & DIFF_FORMAT_PATCH) {
2327                 if (separator) {
2328                         if (options->stat_sep) {
2329                                 /* attach patch instead of inline */
2330                                 fputs(options->stat_sep, stdout);
2331                         } else {
2332                                 putchar(options->line_termination);
2333                         }
2334                 }
2335
2336                 for (i = 0; i < q->nr; i++) {
2337                         struct diff_filepair *p = q->queue[i];
2338                         if (check_pair_status(p))
2339                                 diff_flush_patch(p, options);
2340                 }
2341         }
2342
2343         for (i = 0; i < q->nr; i++)
2344                 diff_free_filepair(q->queue[i]);
2345 free_queue:
2346         free(q->queue);
2347         q->queue = NULL;
2348         q->nr = q->alloc = 0;
2349 }
2350
2351 static void diffcore_apply_filter(const char *filter)
2352 {
2353         int i;
2354         struct diff_queue_struct *q = &diff_queued_diff;
2355         struct diff_queue_struct outq;
2356         outq.queue = NULL;
2357         outq.nr = outq.alloc = 0;
2358
2359         if (!filter)
2360                 return;
2361
2362         if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
2363                 int found;
2364                 for (i = found = 0; !found && i < q->nr; i++) {
2365                         struct diff_filepair *p = q->queue[i];
2366                         if (((p->status == DIFF_STATUS_MODIFIED) &&
2367                              ((p->score &&
2368                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
2369                               (!p->score &&
2370                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
2371                             ((p->status != DIFF_STATUS_MODIFIED) &&
2372                              strchr(filter, p->status)))
2373                                 found++;
2374                 }
2375                 if (found)
2376                         return;
2377
2378                 /* otherwise we will clear the whole queue
2379                  * by copying the empty outq at the end of this
2380                  * function, but first clear the current entries
2381                  * in the queue.
2382                  */
2383                 for (i = 0; i < q->nr; i++)
2384                         diff_free_filepair(q->queue[i]);
2385         }
2386         else {
2387                 /* Only the matching ones */
2388                 for (i = 0; i < q->nr; i++) {
2389                         struct diff_filepair *p = q->queue[i];
2390
2391                         if (((p->status == DIFF_STATUS_MODIFIED) &&
2392                              ((p->score &&
2393                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
2394                               (!p->score &&
2395                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
2396                             ((p->status != DIFF_STATUS_MODIFIED) &&
2397                              strchr(filter, p->status)))
2398                                 diff_q(&outq, p);
2399                         else
2400                                 diff_free_filepair(p);
2401                 }
2402         }
2403         free(q->queue);
2404         *q = outq;
2405 }
2406
2407 void diffcore_std(struct diff_options *options)
2408 {
2409         if (options->break_opt != -1)
2410                 diffcore_break(options->break_opt);
2411         if (options->detect_rename)
2412                 diffcore_rename(options);
2413         if (options->break_opt != -1)
2414                 diffcore_merge_broken();
2415         if (options->pickaxe)
2416                 diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
2417         if (options->orderfile)
2418                 diffcore_order(options->orderfile);
2419         diff_resolve_rename_copy();
2420         diffcore_apply_filter(options->filter);
2421 }
2422
2423
2424 void diffcore_std_no_resolve(struct diff_options *options)
2425 {
2426         if (options->pickaxe)
2427                 diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
2428         if (options->orderfile)
2429                 diffcore_order(options->orderfile);
2430         diffcore_apply_filter(options->filter);
2431 }
2432
2433 void diff_addremove(struct diff_options *options,
2434                     int addremove, unsigned mode,
2435                     const unsigned char *sha1,
2436                     const char *base, const char *path)
2437 {
2438         char concatpath[PATH_MAX];
2439         struct diff_filespec *one, *two;
2440
2441         /* This may look odd, but it is a preparation for
2442          * feeding "there are unchanged files which should
2443          * not produce diffs, but when you are doing copy
2444          * detection you would need them, so here they are"
2445          * entries to the diff-core.  They will be prefixed
2446          * with something like '=' or '*' (I haven't decided
2447          * which but should not make any difference).
2448          * Feeding the same new and old to diff_change()
2449          * also has the same effect.
2450          * Before the final output happens, they are pruned after
2451          * merged into rename/copy pairs as appropriate.
2452          */
2453         if (options->reverse_diff)
2454                 addremove = (addremove == '+' ? '-' :
2455                              addremove == '-' ? '+' : addremove);
2456
2457         if (!path) path = "";
2458         sprintf(concatpath, "%s%s", base, path);
2459         one = alloc_filespec(concatpath);
2460         two = alloc_filespec(concatpath);
2461
2462         if (addremove != '+')
2463                 fill_filespec(one, sha1, mode);
2464         if (addremove != '-')
2465                 fill_filespec(two, sha1, mode);
2466
2467         diff_queue(&diff_queued_diff, one, two);
2468 }
2469
2470 void diff_change(struct diff_options *options,
2471                  unsigned old_mode, unsigned new_mode,
2472                  const unsigned char *old_sha1,
2473                  const unsigned char *new_sha1,
2474                  const char *base, const char *path)
2475 {
2476         char concatpath[PATH_MAX];
2477         struct diff_filespec *one, *two;
2478
2479         if (options->reverse_diff) {
2480                 unsigned tmp;
2481                 const unsigned char *tmp_c;
2482                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
2483                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
2484         }
2485         if (!path) path = "";
2486         sprintf(concatpath, "%s%s", base, path);
2487         one = alloc_filespec(concatpath);
2488         two = alloc_filespec(concatpath);
2489         fill_filespec(one, old_sha1, old_mode);
2490         fill_filespec(two, new_sha1, new_mode);
2491
2492         diff_queue(&diff_queued_diff, one, two);
2493 }
2494
2495 void diff_unmerge(struct diff_options *options,
2496                   const char *path)
2497 {
2498         struct diff_filespec *one, *two;
2499         one = alloc_filespec(path);
2500         two = alloc_filespec(path);
2501         diff_queue(&diff_queued_diff, one, two);
2502 }