apply.c

   1 /*
   2  * apply.c
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  *
   6  * This applies patches on top of some (arbitrary) version of the SCM.
   7  *
   8  * NOTE! It does all its work in the index file, and only cares about
   9  * the files in the working directory if you tell it to "merge" the
  10  * patch apply.
  11  *
  12  * Even when merging it always takes the source from the index, and
  13  * uses the working tree as a "branch" for a 3-way merge.
  14  */
  15 #include <ctype.h>
  16 #include <fnmatch.h>
  17 #include "cache.h"
  18
  19 // We default to the merge behaviour, since that's what most people would
  20 // expect.
  21 //
  22 //  --check turns on checking that the working tree matches the
  23 //    files that are being modified, but doesn't apply the patch
  24 //  --stat does just a diffstat, and doesn't actually apply
  25 //  --show-files shows the directory changes
  26 //
  27 static int merge_patch = 1;
  28 static int check_index = 0;
  29 static int write_index = 0;
  30 static int diffstat = 0;
  31 static int summary = 0;
  32 static int check = 0;
  33 static int apply = 1;
  34 static int show_files = 0;
  35 static const char apply_usage[] =
  36 "git-apply [--no-merge] [--stat] [--summary] [--check] [--index] [--apply] [--show-files] <patch>...";
  37
  38 /*
  39  * For "diff-stat" like behaviour, we keep track of the biggest change
  40  * we've seen, and the longest filename. That allows us to do simple
  41  * scaling.
  42  */
  43 static int max_change, max_len;
  44
  45 /*
  46  * Various "current state", notably line numbers and what
  47  * file (and how) we're patching right now.. The "is_xxxx"
  48  * things are flags, where -1 means "don't know yet".
  49  */
  50 static int linenr = 1;
  51
  52 struct fragment {
  53         unsigned long oldpos, oldlines;
  54         unsigned long newpos, newlines;
  55         const char *patch;
  56         int size;
  57         struct fragment *next;
  58 };
  59
  60 struct patch {
  61         char *new_name, *old_name, *def_name;
  62         unsigned int old_mode, new_mode;
  63         int is_rename, is_copy, is_new, is_delete;
  64         int lines_added, lines_deleted;
  65         int score;
  66         struct fragment *fragments;
  67         char *result;
  68         unsigned long resultsize;
  69         struct patch *next;
  70 };
  71
  72 #define CHUNKSIZE (8192)
  73 #define SLOP (16)
  74
  75 static void *read_patch_file(int fd, unsigned long *sizep)
  76 {
  77         unsigned long size = 0, alloc = CHUNKSIZE;
  78         void *buffer = xmalloc(alloc);
  79
  80         for (;;) {
  81                 int nr = alloc - size;
  82                 if (nr < 1024) {
  83                         alloc += CHUNKSIZE;
  84                         buffer = xrealloc(buffer, alloc);
  85                         nr = alloc - size;
  86                 }
  87                 nr = read(fd, buffer + size, nr);
  88                 if (!nr)
  89                         break;
  90                 if (nr < 0) {
  91                         if (errno == EAGAIN)
  92                                 continue;
  93                         die("git-apply: read returned %s", strerror(errno));
  94                 }
  95                 size += nr;
  96         }
  97         *sizep = size;
  98
  99         /*
 100          * Make sure that we have some slop in the buffer
 101          * so that we can do speculative "memcmp" etc, and
 102          * see to it that it is NUL-filled.
 103          */
 104         if (alloc < size + SLOP)
 105                 buffer = xrealloc(buffer, size + SLOP);
 106         memset(buffer + size, 0, SLOP);
 107         return buffer;
 108 }
 109
 110 static unsigned long linelen(const char *buffer, unsigned long size)
 111 {
 112         unsigned long len = 0;
 113         while (size--) {
 114                 len++;
 115                 if (*buffer++ == '\n')
 116                         break;
 117         }
 118         return len;
 119 }
 120
 121 static int is_dev_null(const char *str)
 122 {
 123         return !memcmp("/dev/null", str, 9) && isspace(str[9]);
 124 }
 125
 126 #define TERM_SPACE      1
 127 #define TERM_TAB        2
 128
 129 static int name_terminate(const char *name, int namelen, int c, int terminate)
 130 {
 131         if (c == ' ' && !(terminate & TERM_SPACE))
 132                 return 0;
 133         if (c == '\t' && !(terminate & TERM_TAB))
 134                 return 0;
 135
 136         return 1;
 137 }
 138
 139 static char * find_name(const char *line, char *def, int p_value, int terminate)
 140 {
 141         int len;
 142         const char *start = line;
 143         char *name;
 144
 145         for (;;) {
 146                 char c = *line;
 147
 148                 if (isspace(c)) {
 149                         if (c == '\n')
 150                                 break;
 151                         if (name_terminate(start, line-start, c, terminate))
 152                                 break;
 153                 }
 154                 line++;
 155                 if (c == '/' && !--p_value)
 156                         start = line;
 157         }
 158         if (!start)
 159                 return def;
 160         len = line - start;
 161         if (!len)
 162                 return def;
 163
 164         /*
 165          * Generally we prefer the shorter name, especially
 166          * if the other one is just a variation of that with
 167          * something else tacked on to the end (ie "file.orig"
 168          * or "file~").
 169          */
 170         if (def) {
 171                 int deflen = strlen(def);
 172                 if (deflen < len && !strncmp(start, def, deflen))
 173                         return def;
 174         }
 175
 176         name = xmalloc(len + 1);
 177         memcpy(name, start, len);
 178         name[len] = 0;
 179         free(def);
 180         return name;
 181 }
 182
 183 /*
 184  * Get the name etc info from the --/+++ lines of a traditional patch header
 185  *
 186  * NOTE! This hardcodes "-p1" behaviour in filename detection.
 187  *
 188  * FIXME! The end-of-filename heuristics are kind of screwy. For existing
 189  * files, we can happily check the index for a match, but for creating a
 190  * new file we should try to match whatever "patch" does. I have no idea.
 191  */
 192 static void parse_traditional_patch(const char *first, const char *second, struct patch *patch)
 193 {
 194         int p_value = 1;
 195         char *name;
 196
 197         first += 4;     // skip "--- "
 198         second += 4;    // skip "+++ "
 199         if (is_dev_null(first)) {
 200                 patch->is_new = 1;
 201                 patch->is_delete = 0;
 202                 name = find_name(second, NULL, p_value, TERM_SPACE | TERM_TAB);
 203                 patch->new_name = name;
 204         } else if (is_dev_null(second)) {
 205                 patch->is_new = 0;
 206                 patch->is_delete = 1;
 207                 name = find_name(first, NULL, p_value, TERM_SPACE | TERM_TAB);
 208                 patch->old_name = name;
 209         } else {
 210                 name = find_name(first, NULL, p_value, TERM_SPACE | TERM_TAB);
 211                 name = find_name(second, name, p_value, TERM_SPACE | TERM_TAB);
 212                 patch->old_name = patch->new_name = name;
 213         }
 214         if (!name)
 215                 die("unable to find filename in patch at line %d", linenr);
 216 }
 217
 218 static int gitdiff_hdrend(const char *line, struct patch *patch)
 219 {
 220         return -1;
 221 }
 222
 223 /*
 224  * We're anal about diff header consistency, to make
 225  * sure that we don't end up having strange ambiguous
 226  * patches floating around.
 227  *
 228  * As a result, gitdiff_{old|new}name() will check
 229  * their names against any previous information, just
 230  * to make sure..
 231  */
 232 static char *gitdiff_verify_name(const char *line, int isnull, char *orig_name, const char *oldnew)
 233 {
 234         int len;
 235         const char *name;
 236
 237         if (!orig_name && !isnull)
 238                 return find_name(line, NULL, 1, 0);
 239
 240         name = "/dev/null";
 241         len = 9;
 242         if (orig_name) {
 243                 name = orig_name;
 244                 len = strlen(name);
 245                 if (isnull)
 246                         die("git-apply: bad git-diff - expected /dev/null, got %s on line %d", name, linenr);
 247         }
 248
 249         if (*name == '/')
 250                 goto absolute_path;
 251
 252         for (;;) {
 253                 char c = *line++;
 254                 if (c == '\n')
 255                         break;
 256                 if (c != '/')
 257                         continue;
 258 absolute_path:
 259                 if (memcmp(line, name, len) || line[len] != '\n')
 260                         break;
 261                 return orig_name;
 262         }
 263         die("git-apply: bad git-diff - inconsistent %s filename on line %d", oldnew, linenr);
 264         return NULL;
 265 }
 266
 267 static int gitdiff_oldname(const char *line, struct patch *patch)
 268 {
 269         patch->old_name = gitdiff_verify_name(line, patch->is_new, patch->old_name, "old");
 270         return 0;
 271 }
 272
 273 static int gitdiff_newname(const char *line, struct patch *patch)
 274 {
 275         patch->new_name = gitdiff_verify_name(line, patch->is_delete, patch->new_name, "new");
 276         return 0;
 277 }
 278
 279 static int gitdiff_oldmode(const char *line, struct patch *patch)
 280 {
 281         patch->old_mode = strtoul(line, NULL, 8);
 282         return 0;
 283 }
 284
 285 static int gitdiff_newmode(const char *line, struct patch *patch)
 286 {
 287         patch->new_mode = strtoul(line, NULL, 8);
 288         return 0;
 289 }
 290
 291 static int gitdiff_delete(const char *line, struct patch *patch)
 292 {
 293         patch->is_delete = 1;
 294         patch->old_name = patch->def_name;
 295         return gitdiff_oldmode(line, patch);
 296 }
 297
 298 static int gitdiff_newfile(const char *line, struct patch *patch)
 299 {
 300         patch->is_new = 1;
 301         patch->new_name = patch->def_name;
 302         return gitdiff_newmode(line, patch);
 303 }
 304
 305 static int gitdiff_copysrc(const char *line, struct patch *patch)
 306 {
 307         patch->is_copy = 1;
 308         patch->old_name = find_name(line, NULL, 0, 0);
 309         return 0;
 310 }
 311
 312 static int gitdiff_copydst(const char *line, struct patch *patch)
 313 {
 314         patch->is_copy = 1;
 315         patch->new_name = find_name(line, NULL, 0, 0);
 316         return 0;
 317 }
 318
 319 static int gitdiff_renamesrc(const char *line, struct patch *patch)
 320 {
 321         patch->is_rename = 1;
 322         patch->old_name = find_name(line, NULL, 0, 0);
 323         return 0;
 324 }
 325
 326 static int gitdiff_renamedst(const char *line, struct patch *patch)
 327 {
 328         patch->is_rename = 1;
 329         patch->new_name = find_name(line, NULL, 0, 0);
 330         return 0;
 331 }
 332
 333 static int gitdiff_similarity(const char *line, struct patch *patch)
 334 {
 335         if ((patch->score = strtoul(line, NULL, 10)) == ULONG_MAX)
 336                 patch->score = 0;
 337         return 0;
 338 }
 339
 340 static int gitdiff_dissimilarity(const char *line, struct patch *patch)
 341 {
 342         if ((patch->score = strtoul(line, NULL, 10)) == ULONG_MAX)
 343                 patch->score = 0;
 344         return 0;
 345 }
 346
 347 /*
 348  * This is normal for a diff that doesn't change anything: we'll fall through
 349  * into the next diff. Tell the parser to break out.
 350  */
 351 static int gitdiff_unrecognized(const char *line, struct patch *patch)
 352 {
 353         return -1;
 354 }
 355
 356 static char *git_header_name(char *line)
 357 {
 358         int len;
 359         char *name, *second;
 360
 361         /*
 362          * Find the first '/'
 363          */
 364         name = line;
 365         for (;;) {
 366                 char c = *name++;
 367                 if (c == '\n')
 368                         return NULL;
 369                 if (c == '/')
 370                         break;
 371         }
 372
 373         /*
 374          * We don't accept absolute paths (/dev/null) as possibly valid
 375          */
 376         if (name == line+1)
 377                 return NULL;
 378
 379         /*
 380          * Accept a name only if it shows up twice, exactly the same
 381          * form.
 382          */
 383         for (len = 0 ; ; len++) {
 384                 char c = name[len];
 385
 386                 switch (c) {
 387                 default:
 388                         continue;
 389                 case '\n':
 390                         return NULL;
 391                 case '\t': case ' ':
 392                         second = name+len;
 393                         for (;;) {
 394                                 char c = *second++;
 395                                 if (c == '\n')
 396                                         return NULL;
 397                                 if (c == '/')
 398                                         break;
 399                         }
 400                         if (second[len] == '\n' && !memcmp(name, second, len)) {
 401                                 char *ret = xmalloc(len + 1);
 402                                 memcpy(ret, name, len);
 403                                 ret[len] = 0;
 404                                 return ret;
 405                         }
 406                 }
 407         }
 408         return NULL;
 409 }
 410
 411 /* Verify that we recognize the lines following a git header */
 412 static int parse_git_header(char *line, int len, unsigned int size, struct patch *patch)
 413 {
 414         unsigned long offset;
 415
 416         /* A git diff has explicit new/delete information, so we don't guess */
 417         patch->is_new = 0;
 418         patch->is_delete = 0;
 419
 420         /*
 421          * Some things may not have the old name in the
 422          * rest of the headers anywhere (pure mode changes,
 423          * or removing or adding empty files), so we get
 424          * the default name from the header.
 425          */
 426         patch->def_name = git_header_name(line + strlen("diff --git "));
 427
 428         line += len;
 429         size -= len;
 430         linenr++;
 431         for (offset = len ; size > 0 ; offset += len, size -= len, line += len, linenr++) {
 432                 static const struct opentry {
 433                         const char *str;
 434                         int (*fn)(const char *, struct patch *);
 435                 } optable[] = {
 436                         { "@@ -", gitdiff_hdrend },
 437                         { "--- ", gitdiff_oldname },
 438                         { "+++ ", gitdiff_newname },
 439                         { "old mode ", gitdiff_oldmode },
 440                         { "new mode ", gitdiff_newmode },
 441                         { "deleted file mode ", gitdiff_delete },
 442                         { "new file mode ", gitdiff_newfile },
 443                         { "copy from ", gitdiff_copysrc },
 444                         { "copy to ", gitdiff_copydst },
 445                         { "rename old ", gitdiff_renamesrc },
 446                         { "rename new ", gitdiff_renamedst },
 447                         { "rename from ", gitdiff_renamesrc },
 448                         { "rename to ", gitdiff_renamedst },
 449                         { "similarity index ", gitdiff_similarity },
 450                         { "dissimilarity index ", gitdiff_dissimilarity },
 451                         { "", gitdiff_unrecognized },
 452                 };
 453                 int i;
 454
 455                 len = linelen(line, size);
 456                 if (!len || line[len-1] != '\n')
 457                         break;
 458                 for (i = 0; i < sizeof(optable) / sizeof(optable[0]); i++) {
 459                         const struct opentry *p = optable + i;
 460                         int oplen = strlen(p->str);
 461                         if (len < oplen || memcmp(p->str, line, oplen))
 462                                 continue;
 463                         if (p->fn(line + oplen, patch) < 0)
 464                                 return offset;
 465                         break;
 466                 }
 467         }
 468
 469         return offset;
 470 }
 471
 472 static int parse_num(const char *line, unsigned long *p)
 473 {
 474         char *ptr;
 475
 476         if (!isdigit(*line))
 477                 return 0;
 478         *p = strtoul(line, &ptr, 10);
 479         return ptr - line;
 480 }
 481
 482 static int parse_range(const char *line, int len, int offset, const char *expect,
 483                         unsigned long *p1, unsigned long *p2)
 484 {
 485         int digits, ex;
 486
 487         if (offset < 0 || offset >= len)
 488                 return -1;
 489         line += offset;
 490         len -= offset;
 491
 492         digits = parse_num(line, p1);
 493         if (!digits)
 494                 return -1;
 495
 496         offset += digits;
 497         line += digits;
 498         len -= digits;
 499
 500         *p2 = *p1;
 501         if (*line == ',') {
 502                 digits = parse_num(line+1, p2);
 503                 if (!digits)
 504                         return -1;
 505
 506                 offset += digits+1;
 507                 line += digits+1;
 508                 len -= digits+1;
 509         }
 510
 511         ex = strlen(expect);
 512         if (ex > len)
 513                 return -1;
 514         if (memcmp(line, expect, ex))
 515                 return -1;
 516
 517         return offset + ex;
 518 }
 519
 520 /*
 521  * Parse a unified diff fragment header of the
 522  * form "@@ -a,b +c,d @@"
 523  */
 524 static int parse_fragment_header(char *line, int len, struct fragment *fragment)
 525 {
 526         int offset;
 527
 528         if (!len || line[len-1] != '\n')
 529                 return -1;
 530
 531         /* Figure out the number of lines in a fragment */
 532         offset = parse_range(line, len, 4, " +", &fragment->oldpos, &fragment->oldlines);
 533         offset = parse_range(line, len, offset, " @@", &fragment->newpos, &fragment->newlines);
 534
 535         return offset;
 536 }
 537
 538 static int find_header(char *line, unsigned long size, int *hdrsize, struct patch *patch)
 539 {
 540         unsigned long offset, len;
 541
 542         patch->is_rename = patch->is_copy = 0;
 543         patch->is_new = patch->is_delete = -1;
 544         patch->old_mode = patch->new_mode = 0;
 545         patch->old_name = patch->new_name = NULL;
 546         for (offset = 0; size > 0; offset += len, size -= len, line += len, linenr++) {
 547                 unsigned long nextlen;
 548
 549                 len = linelen(line, size);
 550                 if (!len)
 551                         break;
 552
 553                 /* Testing this early allows us to take a few shortcuts.. */
 554                 if (len < 6)
 555                         continue;
 556
 557                 /*
 558                  * Make sure we don't find any unconnected patch fragmants.
 559                  * That's a sign that we didn't find a header, and that a
 560                  * patch has become corrupted/broken up.
 561                  */
 562                 if (!memcmp("@@ -", line, 4)) {
 563                         struct fragment dummy;
 564                         if (parse_fragment_header(line, len, &dummy) < 0)
 565                                 continue;
 566                         error("patch fragment without header at line %d: %.*s", linenr, (int)len-1, line);
 567                 }
 568
 569                 if (size < len + 6)
 570                         break;
 571
 572                 /*
 573                  * Git patch? It might not have a real patch, just a rename
 574                  * or mode change, so we handle that specially
 575                  */
 576                 if (!memcmp("diff --git ", line, 11)) {
 577                         int git_hdr_len = parse_git_header(line, len, size, patch);
 578                         if (git_hdr_len <= len)
 579                                 continue;
 580                         if (!patch->old_name && !patch->new_name) {
 581                                 if (!patch->def_name)
 582                                         die("git diff header lacks filename information (line %d)", linenr);
 583                                 patch->old_name = patch->new_name = patch->def_name;
 584                         }
 585                         *hdrsize = git_hdr_len;
 586                         return offset;
 587                 }
 588
 589                 /** --- followed by +++ ? */
 590                 if (memcmp("--- ", line,  4) || memcmp("+++ ", line + len, 4))
 591                         continue;
 592
 593                 /*
 594                  * We only accept unified patches, so we want it to
 595                  * at least have "@@ -a,b +c,d @@\n", which is 14 chars
 596                  * minimum
 597                  */
 598                 nextlen = linelen(line + len, size - len);
 599                 if (size < nextlen + 14 || memcmp("@@ -", line + len + nextlen, 4))
 600                         continue;
 601
 602                 /* Ok, we'll consider it a patch */
 603                 parse_traditional_patch(line, line+len, patch);
 604                 *hdrsize = len + nextlen;
 605                 linenr += 2;
 606                 return offset;
 607         }
 608         return -1;
 609 }
 610
 611 /*
 612  * Parse a unified diff. Note that this really needs
 613  * to parse each fragment separately, since the only
 614  * way to know the difference between a "---" that is
 615  * part of a patch, and a "---" that starts the next
 616  * patch is to look at the line counts..
 617  */
 618 static int parse_fragment(char *line, unsigned long size, struct patch *patch, struct fragment *fragment)
 619 {
 620         int added, deleted;
 621         int len = linelen(line, size), offset;
 622         unsigned long oldlines, newlines;
 623
 624         offset = parse_fragment_header(line, len, fragment);
 625         if (offset < 0)
 626                 return -1;
 627         oldlines = fragment->oldlines;
 628         newlines = fragment->newlines;
 629
 630         if (patch->is_new < 0) {
 631                 patch->is_new =  !oldlines;
 632                 if (!oldlines)
 633                         patch->old_name = NULL;
 634         }
 635         if (patch->is_delete < 0) {
 636                 patch->is_delete = !newlines;
 637                 if (!newlines)
 638                         patch->new_name = NULL;
 639         }
 640
 641         if (patch->is_new != !oldlines)
 642                 return error("new file depends on old contents");
 643         if (patch->is_delete != !newlines) {
 644                 if (newlines)
 645                         return error("deleted file still has contents");
 646                 fprintf(stderr, "** warning: file %s becomes empty but is not deleted\n", patch->new_name);
 647         }
 648
 649         /* Parse the thing.. */
 650         line += len;
 651         size -= len;
 652         linenr++;
 653         added = deleted = 0;
 654         for (offset = len; size > 0; offset += len, size -= len, line += len, linenr++) {
 655                 if (!oldlines && !newlines)
 656                         break;
 657                 len = linelen(line, size);
 658                 if (!len || line[len-1] != '\n')
 659                         return -1;
 660                 switch (*line) {
 661                 default:
 662                         return -1;
 663                 case ' ':
 664                         oldlines--;
 665                         newlines--;
 666                         break;
 667                 case '-':
 668                         deleted++;
 669                         oldlines--;
 670                         break;
 671                 case '+':
 672                         added++;
 673                         newlines--;
 674                         break;
 675
 676                 /* We allow "\ No newline at end of file". Depending
 677                  * on locale settings when the patch was produced we
 678                  * don't know what this line looks like. The only
 679                  * thing we do know is that it begins with "\ ". */
 680                 case '\\':
 681                         if (len < 12 || memcmp(line, "\\ ", 2))
 682                                 return -1;
 683                         break;
 684                 }
 685         }
 686         /* If a fragment ends with an incomplete line, we failed to include
 687          * it in the above loop because we hit oldlines == newlines == 0
 688          * before seeing it.
 689          */
 690         if (12 < size && !memcmp(line, "\\ ", 2))
 691                 offset += linelen(line, size);
 692
 693         patch->lines_added += added;
 694         patch->lines_deleted += deleted;
 695         return offset;
 696 }
 697
 698 static int parse_single_patch(char *line, unsigned long size, struct patch *patch)
 699 {
 700         unsigned long offset = 0;
 701         struct fragment **fragp = &patch->fragments;
 702
 703         while (size > 4 && !memcmp(line, "@@ -", 4)) {
 704                 struct fragment *fragment;
 705                 int len;
 706
 707                 fragment = xmalloc(sizeof(*fragment));
 708                 memset(fragment, 0, sizeof(*fragment));
 709                 len = parse_fragment(line, size, patch, fragment);
 710                 if (len <= 0)
 711                         die("corrupt patch at line %d", linenr);
 712
 713                 fragment->patch = line;
 714                 fragment->size = len;
 715
 716                 *fragp = fragment;
 717                 fragp = &fragment->next;
 718
 719                 offset += len;
 720                 line += len;
 721                 size -= len;
 722         }
 723         return offset;
 724 }
 725
 726 static inline int metadata_changes(struct patch *patch)
 727 {
 728         return  patch->is_rename > 0 ||
 729                 patch->is_copy > 0 ||
 730                 patch->is_new > 0 ||
 731                 patch->is_delete ||
 732                 (patch->old_mode && patch->new_mode &&
 733                  patch->old_mode != patch->new_mode);
 734 }
 735
 736 static int parse_chunk(char *buffer, unsigned long size, struct patch *patch)
 737 {
 738         int hdrsize, patchsize;
 739         int offset = find_header(buffer, size, &hdrsize, patch);
 740
 741         if (offset < 0)
 742                 return offset;
 743
 744         patchsize = parse_single_patch(buffer + offset + hdrsize, size - offset - hdrsize, patch);
 745
 746         if (!patchsize && !metadata_changes(patch))
 747                 die("patch with only garbage at line %d", linenr);
 748
 749         return offset + hdrsize + patchsize;
 750 }
 751
 752 static const char pluses[] = "++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++";
 753 static const char minuses[]= "----------------------------------------------------------------------";
 754
 755 static void show_stats(struct patch *patch)
 756 {
 757         const char *prefix = "";
 758         char *name = patch->new_name;
 759         int len, max, add, del, total;
 760
 761         if (!name)
 762                 name = patch->old_name;
 763
 764         /*
 765          * "scale" the filename
 766          */
 767         len = strlen(name);
 768         max = max_len;
 769         if (max > 50)
 770                 max = 50;
 771         if (len > max) {
 772                 char *slash;
 773                 prefix = "...";
 774                 max -= 3;
 775                 name += len - max;
 776                 slash = strchr(name, '/');
 777                 if (slash)
 778                         name = slash;
 779         }
 780         len = max;
 781
 782         /*
 783          * scale the add/delete
 784          */
 785         max = max_change;
 786         if (max + len > 70)
 787                 max = 70 - len;
 788
 789         add = patch->lines_added;
 790         del = patch->lines_deleted;
 791         total = add + del;
 792
 793         if (max_change > 0) {
 794                 total = (total * max + max_change / 2) / max_change;
 795                 add = (add * max + max_change / 2) / max_change;
 796                 del = total - add;
 797         }
 798         printf(" %s%-*s |%5d %.*s%.*s\n", prefix,
 799                 len, name, patch->lines_added + patch->lines_deleted,
 800                 add, pluses, del, minuses);
 801 }
 802
 803 static int read_old_data(struct stat *st, const char *path, void *buf, unsigned long size)
 804 {
 805         int fd;
 806         unsigned long got;
 807
 808         switch (st->st_mode & S_IFMT) {
 809         case S_IFLNK:
 810                 return readlink(path, buf, size);
 811         case S_IFREG:
 812                 fd = open(path, O_RDONLY);
 813                 if (fd < 0)
 814                         return error("unable to open %s", path);
 815                 got = 0;
 816                 for (;;) {
 817                         int ret = read(fd, buf + got, size - got);
 818                         if (ret < 0) {
 819                                 if (errno == EAGAIN)
 820                                         continue;
 821                                 break;
 822                         }
 823                         if (!ret)
 824                                 break;
 825                         got += ret;
 826                 }
 827                 close(fd);
 828                 return got;
 829
 830         default:
 831                 return -1;
 832         }
 833 }
 834
 835 static int find_offset(const char *buf, unsigned long size, const char *fragment, unsigned long fragsize, int line)
 836 {
 837         int i;
 838         unsigned long start, backwards, forwards;
 839
 840         if (fragsize > size)
 841                 return -1;
 842
 843         start = 0;
 844         if (line > 1) {
 845                 unsigned long offset = 0;
 846                 i = line-1;
 847                 while (offset + fragsize <= size) {
 848                         if (buf[offset++] == '\n') {
 849                                 start = offset;
 850                                 if (!--i)
 851                                         break;
 852                         }
 853                 }
 854         }
 855
 856         /* Exact line number? */
 857         if (!memcmp(buf + start, fragment, fragsize))
 858                 return start;
 859
 860         /*
 861          * There's probably some smart way to do this, but I'll leave
 862          * that to the smart and beautiful people. I'm simple and stupid.
 863          */
 864         backwards = start;
 865         forwards = start;
 866         for (i = 0; ; i++) {
 867                 unsigned long try;
 868                 int n;
 869
 870                 /* "backward" */
 871                 if (i & 1) {
 872                         if (!backwards) {
 873                                 if (forwards + fragsize > size)
 874                                         break;
 875                                 continue;
 876                         }
 877                         do {
 878                                 --backwards;
 879                         } while (backwards && buf[backwards-1] != '\n');
 880                         try = backwards;
 881                 } else {
 882                         while (forwards + fragsize <= size) {
 883                                 if (buf[forwards++] == '\n')
 884                                         break;
 885                         }
 886                         try = forwards;
 887                 }
 888
 889                 if (try + fragsize > size)
 890                         continue;
 891                 if (memcmp(buf + try, fragment, fragsize))
 892                         continue;
 893                 n = (i >> 1)+1;
 894                 if (i & 1)
 895                         n = -n;
 896                 return try;
 897         }
 898
 899         /*
 900          * We should start searching forward and backward.
 901          */
 902         return -1;
 903 }
 904
 905 struct buffer_desc {
 906         char *buffer;
 907         unsigned long size;
 908         unsigned long alloc;
 909 };
 910
 911 static int apply_one_fragment(struct buffer_desc *desc, struct fragment *frag)
 912 {
 913         char *buf = desc->buffer;
 914         const char *patch = frag->patch;
 915         int offset, size = frag->size;
 916         char *old = xmalloc(size);
 917         char *new = xmalloc(size);
 918         int oldsize = 0, newsize = 0;
 919
 920         while (size > 0) {
 921                 int len = linelen(patch, size);
 922                 int plen;
 923
 924                 if (!len)
 925                         break;
 926
 927                 /*
 928                  * "plen" is how much of the line we should use for
 929                  * the actual patch data. Normally we just remove the
 930                  * first character on the line, but if the line is
 931                  * followed by "\ No newline", then we also remove the
 932                  * last one (which is the newline, of course).
 933                  */
 934                 plen = len-1;
 935                 if (len < size && patch[len] == '\\')
 936                         plen--;
 937                 switch (*patch) {
 938                 case ' ':
 939                 case '-':
 940                         memcpy(old + oldsize, patch + 1, plen);
 941                         oldsize += plen;
 942                         if (*patch == '-')
 943                                 break;
 944                 /* Fall-through for ' ' */
 945                 case '+':
 946                         memcpy(new + newsize, patch + 1, plen);
 947                         newsize += plen;
 948                         break;
 949                 case '@': case '\\':
 950                         /* Ignore it, we already handled it */
 951                         break;
 952                 default:
 953                         return -1;
 954                 }
 955                 patch += len;
 956                 size -= len;
 957         }
 958
 959         offset = find_offset(buf, desc->size, old, oldsize, frag->newpos);
 960         if (offset >= 0) {
 961                 int diff = newsize - oldsize;
 962                 unsigned long size = desc->size + diff;
 963                 unsigned long alloc = desc->alloc;
 964
 965                 if (size > alloc) {
 966                         alloc = size + 8192;
 967                         desc->alloc = alloc;
 968                         buf = xrealloc(buf, alloc);
 969                         desc->buffer = buf;
 970                 }
 971                 desc->size = size;
 972                 memmove(buf + offset + newsize, buf + offset + oldsize, size - offset - newsize);
 973                 memcpy(buf + offset, new, newsize);
 974                 offset = 0;
 975         }
 976
 977         free(old);
 978         free(new);
 979         return offset;
 980 }
 981
 982 static int apply_fragments(struct buffer_desc *desc, struct patch *patch)
 983 {
 984         struct fragment *frag = patch->fragments;
 985
 986         while (frag) {
 987                 if (apply_one_fragment(desc, frag) < 0)
 988                         return error("patch failed: %s:%ld", patch->old_name, frag->oldpos);
 989                 frag = frag->next;
 990         }
 991         return 0;
 992 }
 993
 994 static int apply_data(struct patch *patch, struct stat *st)
 995 {
 996         char *buf;
 997         unsigned long size, alloc;
 998         struct buffer_desc desc;
 999
1000         size = 0;
1001         alloc = 0;
1002         buf = NULL;
1003         if (patch->old_name) {
1004                 size = st->st_size;
1005                 alloc = size + 8192;
1006                 buf = xmalloc(alloc);
1007                 if (read_old_data(st, patch->old_name, buf, alloc) != size)
1008                         return error("read of %s failed", patch->old_name);
1009         }
1010
1011         desc.size = size;
1012         desc.alloc = alloc;
1013         desc.buffer = buf;
1014         if (apply_fragments(&desc, patch) < 0)
1015                 return -1;
1016         patch->result = desc.buffer;
1017         patch->resultsize = desc.size;
1018
1019         if (patch->is_delete && patch->resultsize)
1020                 return error("removal patch leaves file contents");
1021
1022         return 0;
1023 }
1024
1025 static int check_patch(struct patch *patch)
1026 {
1027         struct stat st;
1028         const char *old_name = patch->old_name;
1029         const char *new_name = patch->new_name;
1030
1031         if (old_name) {
1032                 int changed;
1033
1034                 if (lstat(old_name, &st) < 0)
1035                         return error("%s: %s", old_name, strerror(errno));
1036                 if (check_index) {
1037                         int pos = cache_name_pos(old_name, strlen(old_name));
1038                         if (pos < 0)
1039                                 return error("%s: does not exist in index", old_name);
1040                         changed = ce_match_stat(active_cache[pos], &st);
1041                         if (changed)
1042                                 return error("%s: does not match index", old_name);
1043                 }
1044                 if (patch->is_new < 0)
1045                         patch->is_new = 0;
1046                 st.st_mode = ntohl(create_ce_mode(st.st_mode));
1047                 if (!patch->old_mode)
1048                         patch->old_mode = st.st_mode;
1049                 if ((st.st_mode ^ patch->old_mode) & S_IFMT)
1050                         return error("%s: wrong type", old_name);
1051                 if (st.st_mode != patch->old_mode)
1052                         fprintf(stderr, "warning: %s has type %o, expected %o\n",
1053                                 old_name, st.st_mode, patch->old_mode);
1054         }
1055
1056         if (new_name && (patch->is_new | patch->is_rename | patch->is_copy)) {
1057                 if (check_index && cache_name_pos(new_name, strlen(new_name)) >= 0)
1058                         return error("%s: already exists in index", new_name);
1059                 if (!lstat(new_name, &st))
1060                         return error("%s: already exists in working directory", new_name);
1061                 if (errno != ENOENT)
1062                         return error("%s: %s", new_name, strerror(errno));
1063                 if (!patch->new_mode) {
1064                         if (patch->is_new)
1065                                 patch->new_mode = S_IFREG | 0644;
1066                         else
1067                                 patch->new_mode = patch->old_mode;
1068                 }
1069         }
1070
1071         if (new_name && old_name) {
1072                 int same = !strcmp(old_name, new_name);
1073                 if (!patch->new_mode)
1074                         patch->new_mode = patch->old_mode;
1075                 if ((patch->old_mode ^ patch->new_mode) & S_IFMT)
1076                         return error("new mode (%o) of %s does not match old mode (%o)%s%s",
1077                                 patch->new_mode, new_name, patch->old_mode,
1078                                 same ? "" : " of ", same ? "" : old_name);
1079         }
1080
1081         if (apply_data(patch, &st) < 0)
1082                 return error("%s: patch does not apply", old_name);
1083         return 0;
1084 }
1085
1086 static int check_patch_list(struct patch *patch)
1087 {
1088         int error = 0;
1089
1090         for (;patch ; patch = patch->next)
1091                 error |= check_patch(patch);
1092         return error;
1093 }
1094
1095 static void show_file(int c, unsigned int mode, const char *name)
1096 {
1097         printf("%c %o %s\n", c, mode, name);
1098 }
1099
1100 static void show_file_list(struct patch *patch)
1101 {
1102         for (;patch ; patch = patch->next) {
1103                 if (patch->is_rename) {
1104                         show_file('-', patch->old_mode, patch->old_name);
1105                         show_file('+', patch->new_mode, patch->new_name);
1106                         continue;
1107                 }
1108                 if (patch->is_copy || patch->is_new) {
1109                         show_file('+', patch->new_mode, patch->new_name);
1110                         continue;
1111                 }
1112                 if (patch->is_delete) {
1113                         show_file('-', patch->old_mode, patch->old_name);
1114                         continue;
1115                 }
1116                 if (patch->old_mode && patch->new_mode && patch->old_mode != patch->new_mode) {
1117                         printf("M %o:%o %s\n", patch->old_mode, patch->new_mode, patch->old_name);
1118                         continue;
1119                 }
1120                 printf("M %o %s\n", patch->old_mode, patch->old_name);
1121         }
1122 }
1123
1124 static void stat_patch_list(struct patch *patch)
1125 {
1126         int files, adds, dels;
1127
1128         for (files = adds = dels = 0 ; patch ; patch = patch->next) {
1129                 files++;
1130                 adds += patch->lines_added;
1131                 dels += patch->lines_deleted;
1132                 show_stats(patch);
1133         }
1134
1135         printf(" %d files changed, %d insertions(+), %d deletions(-)\n", files, adds, dels);
1136 }
1137
1138 static void show_file_mode_name(const char *newdelete, unsigned int mode, const char *name)
1139 {
1140         if (mode)
1141                 printf(" %s mode %06o %s\n", newdelete, mode, name);
1142         else
1143                 printf(" %s %s\n", newdelete, name);
1144 }
1145
1146 static void show_mode_change(struct patch *p, int show_name)
1147 {
1148         if (p->old_mode && p->new_mode && p->old_mode != p->new_mode) {
1149                 if (show_name)
1150                         printf(" mode change %06o => %06o %s\n",
1151                                p->old_mode, p->new_mode, p->new_name);
1152                 else
1153                         printf(" mode change %06o => %06o\n",
1154                                p->old_mode, p->new_mode);
1155         }
1156 }
1157
1158 static void show_rename_copy(struct patch *p)
1159 {
1160         const char *renamecopy = p->is_rename ? "rename" : "copy";
1161         const char *old, *new;
1162
1163         /* Find common prefix */
1164         old = p->old_name;
1165         new = p->new_name;
1166         while (1) {
1167                 const char *slash_old, *slash_new;
1168                 slash_old = strchr(old, '/');
1169                 slash_new = strchr(new, '/');
1170                 if (!slash_old ||
1171                     !slash_new ||
1172                     slash_old - old != slash_new - new ||
1173                     memcmp(old, new, slash_new - new))
1174                         break;
1175                 old = slash_old + 1;
1176                 new = slash_new + 1;
1177         }
1178         /* p->old_name thru old is the common prefix, and old and new
1179          * through the end of names are renames
1180          */
1181         if (old != p->old_name)
1182                 printf(" %s %.*s{%s => %s} (%d%%)\n", renamecopy,
1183                        (int)(old - p->old_name), p->old_name,
1184                        old, new, p->score);
1185         else
1186                 printf(" %s %s => %s (%d%%)\n", renamecopy,
1187                        p->old_name, p->new_name, p->score);
1188         show_mode_change(p, 0);
1189 }
1190
1191 static void summary_patch_list(struct patch *patch)
1192 {
1193         struct patch *p;
1194
1195         for (p = patch; p; p = p->next) {
1196                 if (p->is_new)
1197                         show_file_mode_name("create", p->new_mode, p->new_name);
1198                 else if (p->is_delete)
1199                         show_file_mode_name("delete", p->old_mode, p->old_name);
1200                 else {
1201                         if (p->is_rename || p->is_copy)
1202                                 show_rename_copy(p);
1203                         else {
1204                                 if (p->score) {
1205                                         printf(" rewrite %s (%d%%)\n",
1206                                                p->new_name, p->score);
1207                                         show_mode_change(p, 0);
1208                                 }
1209                                 else
1210                                         show_mode_change(p, 1);
1211                         }
1212                 }
1213         }
1214 }
1215
1216 static void patch_stats(struct patch *patch)
1217 {
1218         int lines = patch->lines_added + patch->lines_deleted;
1219
1220         if (lines > max_change)
1221                 max_change = lines;
1222         if (patch->old_name) {
1223                 int len = strlen(patch->old_name);
1224                 if (len > max_len)
1225                         max_len = len;
1226         }
1227         if (patch->new_name) {
1228                 int len = strlen(patch->new_name);
1229                 if (len > max_len)
1230                         max_len = len;
1231         }
1232 }
1233
1234 static void remove_file(struct patch *patch)
1235 {
1236         if (write_index) {
1237                 if (remove_file_from_cache(patch->old_name) < 0)
1238                         die("unable to remove %s from index", patch->old_name);
1239         }
1240         unlink(patch->old_name);
1241 }
1242
1243 static void add_index_file(const char *path, unsigned mode, void *buf, unsigned long size)
1244 {
1245         struct stat st;
1246         struct cache_entry *ce;
1247         int namelen = strlen(path);
1248         unsigned ce_size = cache_entry_size(namelen);
1249
1250         if (!write_index)
1251                 return;
1252
1253         ce = xmalloc(ce_size);
1254         memset(ce, 0, ce_size);
1255         memcpy(ce->name, path, namelen);
1256         ce->ce_mode = create_ce_mode(mode);
1257         ce->ce_flags = htons(namelen);
1258         if (lstat(path, &st) < 0)
1259                 die("unable to stat newly created file %s", path);
1260         fill_stat_cache_info(ce, &st);
1261         if (write_sha1_file(buf, size, "blob", ce->sha1) < 0)
1262                 die("unable to create backing store for newly created file %s", path);
1263         if (add_cache_entry(ce, ADD_CACHE_OK_TO_ADD) < 0)
1264                 die("unable to add cache entry for %s", path);
1265 }
1266
1267 static void create_subdirectories(const char *path)
1268 {
1269         int len = strlen(path);
1270         char *buf = xmalloc(len + 1);
1271         const char *slash = path;
1272
1273         while ((slash = strchr(slash+1, '/')) != NULL) {
1274                 len = slash - path;
1275                 memcpy(buf, path, len);
1276                 buf[len] = 0;
1277                 if (mkdir(buf, 0777) < 0) {
1278                         if (errno != EEXIST)
1279                                 break;
1280                 }
1281         }
1282         free(buf);
1283 }
1284
1285 static int try_create_file(const char *path, unsigned int mode, const char *buf, unsigned long size)
1286 {
1287         int fd;
1288
1289         if (S_ISLNK(mode))
1290                 return symlink(buf, path);
1291         fd = open(path, O_CREAT | O_EXCL | O_WRONLY | O_TRUNC, (mode & 0100) ? 0777 : 0666);
1292         if (fd < 0)
1293                 return -1;
1294         while (size) {
1295                 int written = write(fd, buf, size);
1296                 if (written < 0) {
1297                         if (errno == EINTR || errno == EAGAIN)
1298                                 continue;
1299                         die("writing file %s: %s", path, strerror(errno));
1300                 }
1301                 if (!written)
1302                         die("out of space writing file %s", path);
1303                 buf += written;
1304                 size -= written;
1305         }
1306         if (close(fd) < 0)
1307                 die("closing file %s: %s", path, strerror(errno));
1308         return 0;
1309 }
1310
1311 /*
1312  * We optimistically assume that the directories exist,
1313  * which is true 99% of the time anyway. If they don't,
1314  * we create them and try again.
1315  */
1316 static void create_one_file(const char *path, unsigned mode, const char *buf, unsigned long size)
1317 {
1318         if (!try_create_file(path, mode, buf, size))
1319                 return;
1320
1321         if (errno == ENOENT) {
1322                 create_subdirectories(path);
1323                 if (!try_create_file(path, mode, buf, size))
1324                         return;
1325         }
1326
1327         if (errno == EEXIST) {
1328                 unsigned int nr = getpid();
1329
1330                 for (;;) {
1331                         const char *newpath;
1332                         newpath = mkpath("%s~%u", path, nr);
1333                         if (!try_create_file(newpath, mode, buf, size)) {
1334                                 if (!rename(newpath, path))
1335                                         return;
1336                                 unlink(newpath);
1337                                 break;
1338                         }
1339                         if (errno != EEXIST)
1340                                 break;
1341                 }
1342         }
1343         die("unable to write file %s mode %o", path, mode);
1344 }
1345
1346 static void create_file(struct patch *patch)
1347 {
1348         const char *path = patch->new_name;
1349         unsigned mode = patch->new_mode;
1350         unsigned long size = patch->resultsize;
1351         char *buf = patch->result;
1352
1353         if (!mode)
1354                 mode = S_IFREG | 0644;
1355         create_one_file(path, mode, buf, size);
1356         add_index_file(path, mode, buf, size);
1357 }
1358
1359 static void write_out_one_result(struct patch *patch)
1360 {
1361         if (patch->is_delete > 0) {
1362                 remove_file(patch);
1363                 return;
1364         }
1365         if (patch->is_new > 0 || patch->is_copy) {
1366                 create_file(patch);
1367                 return;
1368         }
1369         /*
1370          * Rename or modification boils down to the same
1371          * thing: remove the old, write the new
1372          */
1373         remove_file(patch);
1374         create_file(patch);
1375 }
1376
1377 static void write_out_results(struct patch *list, int skipped_patch)
1378 {
1379         if (!list && !skipped_patch)
1380                 die("No changes");
1381
1382         while (list) {
1383                 write_out_one_result(list);
1384                 list = list->next;
1385         }
1386 }
1387
1388 static struct cache_file cache_file;
1389
1390 static struct excludes {
1391         struct excludes *next;
1392         const char *path;
1393 } *excludes;
1394
1395 static int use_patch(struct patch *p)
1396 {
1397         const char *pathname = p->new_name ? p->new_name : p->old_name;
1398         struct excludes *x = excludes;
1399         while (x) {
1400                 if (fnmatch(x->path, pathname, 0) == 0)
1401                         return 0;
1402                 x = x->next;
1403         }
1404         return 1;
1405 }
1406
1407 static int apply_patch(int fd)
1408 {
1409         int newfd;
1410         unsigned long offset, size;
1411         char *buffer = read_patch_file(fd, &size);
1412         struct patch *list = NULL, **listp = &list;
1413         int skipped_patch = 0;
1414
1415         if (!buffer)
1416                 return -1;
1417         offset = 0;
1418         while (size > 0) {
1419                 struct patch *patch;
1420                 int nr;
1421
1422                 patch = xmalloc(sizeof(*patch));
1423                 memset(patch, 0, sizeof(*patch));
1424                 nr = parse_chunk(buffer + offset, size, patch);
1425                 if (nr < 0)
1426                         break;
1427                 if (use_patch(patch)) {
1428                         patch_stats(patch);
1429                         *listp = patch;
1430                         listp = &patch->next;
1431                 } else {
1432                         /* perhaps free it a bit better? */
1433                         free(patch);
1434                         skipped_patch++;
1435                 }
1436                 offset += nr;
1437                 size -= nr;
1438         }
1439
1440         newfd = -1;
1441         write_index = check_index && apply;
1442         if (write_index)
1443                 newfd = hold_index_file_for_update(&cache_file, get_index_file());
1444         if (check_index) {
1445                 if (read_cache() < 0)
1446                         die("unable to read index file");
1447         }
1448
1449         if ((check || apply) && check_patch_list(list) < 0)
1450                 exit(1);
1451
1452         if (apply)
1453                 write_out_results(list, skipped_patch);
1454
1455         if (write_index) {
1456                 if (write_cache(newfd, active_cache, active_nr) ||
1457                     commit_index_file(&cache_file))
1458                         die("Unable to write new cachefile");
1459         }
1460
1461         if (show_files)
1462                 show_file_list(list);
1463
1464         if (diffstat)
1465                 stat_patch_list(list);
1466
1467         if (summary)
1468                 summary_patch_list(list);
1469
1470         free(buffer);
1471         return 0;
1472 }
1473
1474 int main(int argc, char **argv)
1475 {
1476         int i;
1477         int read_stdin = 1;
1478
1479         for (i = 1; i < argc; i++) {
1480                 const char *arg = argv[i];
1481                 int fd;
1482
1483                 if (!strcmp(arg, "-")) {
1484                         apply_patch(0);
1485                         read_stdin = 0;
1486                         continue;
1487                 }
1488                 if (!strncmp(arg, "--exclude=", 10)) {
1489                         struct excludes *x = xmalloc(sizeof(*x));
1490                         x->path = arg + 10;
1491                         x->next = excludes;
1492                         excludes = x;
1493                         continue;
1494                 }
1495                 /* NEEDSWORK: this does not do anything at this moment. */
1496                 if (!strcmp(arg, "--no-merge")) {
1497                         merge_patch = 0;
1498                         continue;
1499                 }
1500                 if (!strcmp(arg, "--stat")) {
1501                         apply = 0;
1502                         diffstat = 1;
1503                         continue;
1504                 }
1505                 if (!strcmp(arg, "--summary")) {
1506                         apply = 0;
1507                         summary = 1;
1508                         continue;
1509                 }
1510                 if (!strcmp(arg, "--check")) {
1511                         apply = 0;
1512                         check = 1;
1513                         continue;
1514                 }
1515                 if (!strcmp(arg, "--index")) {
1516                         check_index = 1;
1517                         continue;
1518                 }
1519                 if (!strcmp(arg, "--apply")) {
1520                         apply = 1;
1521                         continue;
1522                 }
1523                 if (!strcmp(arg, "--show-files")) {
1524                         show_files = 1;
1525                         continue;
1526                 }
1527                 fd = open(arg, O_RDONLY);
1528                 if (fd < 0)
1529                         usage(apply_usage);
1530                 read_stdin = 0;
1531                 apply_patch(fd);
1532                 close(fd);
1533         }
1534         if (read_stdin)
1535                 apply_patch(0);
1536         return 0;
1537 }