Makefile: iconv() on Darwin has the old interface
[git] / merge-recursive.c
1 /*
2  * Recursive Merge algorithm stolen from git-merge-recursive.py by
3  * Fredrik Kuivinen.
4  * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
5  */
6 #include "cache.h"
7 #include "cache-tree.h"
8 #include "commit.h"
9 #include "blob.h"
10 #include "tree-walk.h"
11 #include "diff.h"
12 #include "diffcore.h"
13 #include "run-command.h"
14 #include "tag.h"
15 #include "unpack-trees.h"
16 #include "path-list.h"
17 #include "xdiff-interface.h"
18
19 /*
20  * A virtual commit has
21  * - (const char *)commit->util set to the name, and
22  * - *(int *)commit->object.sha1 set to the virtual id.
23  */
24
25 static unsigned commit_list_count(const struct commit_list *l)
26 {
27         unsigned c = 0;
28         for (; l; l = l->next )
29                 c++;
30         return c;
31 }
32
33 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
34 {
35         struct commit *commit = xcalloc(1, sizeof(struct commit));
36         static unsigned virtual_id = 1;
37         commit->tree = tree;
38         commit->util = (void*)comment;
39         *(int*)commit->object.sha1 = virtual_id++;
40         /* avoid warnings */
41         commit->object.parsed = 1;
42         return commit;
43 }
44
45 /*
46  * Since we use get_tree_entry(), which does not put the read object into
47  * the object pool, we cannot rely on a == b.
48  */
49 static int sha_eq(const unsigned char *a, const unsigned char *b)
50 {
51         if (!a && !b)
52                 return 2;
53         return a && b && hashcmp(a, b) == 0;
54 }
55
56 /*
57  * Since we want to write the index eventually, we cannot reuse the index
58  * for these (temporary) data.
59  */
60 struct stage_data
61 {
62         struct
63         {
64                 unsigned mode;
65                 unsigned char sha[20];
66         } stages[4];
67         unsigned processed:1;
68 };
69
70 struct output_buffer
71 {
72         struct output_buffer *next;
73         char *str;
74 };
75
76 static struct path_list current_file_set = {NULL, 0, 0, 1};
77 static struct path_list current_directory_set = {NULL, 0, 0, 1};
78
79 static int call_depth = 0;
80 static int verbosity = 2;
81 static int buffer_output = 1;
82 static int do_progress = 1;
83 static unsigned last_percent;
84 static unsigned merged_cnt;
85 static unsigned total_cnt;
86 static volatile sig_atomic_t progress_update;
87 static struct output_buffer *output_list, *output_end;
88
89 static int show (int v)
90 {
91         return (!call_depth && verbosity >= v) || verbosity >= 5;
92 }
93
94 static void output(int v, const char *fmt, ...)
95 {
96         va_list args;
97         va_start(args, fmt);
98         if (buffer_output && show(v)) {
99                 struct output_buffer *b = xmalloc(sizeof(*b));
100                 nfvasprintf(&b->str, fmt, args);
101                 b->next = NULL;
102                 if (output_end)
103                         output_end->next = b;
104                 else
105                         output_list = b;
106                 output_end = b;
107         } else if (show(v)) {
108                 int i;
109                 for (i = call_depth; i--;)
110                         fputs("  ", stdout);
111                 vfprintf(stdout, fmt, args);
112                 fputc('\n', stdout);
113         }
114         va_end(args);
115 }
116
117 static void flush_output()
118 {
119         struct output_buffer *b, *n;
120         for (b = output_list; b; b = n) {
121                 int i;
122                 for (i = call_depth; i--;)
123                         fputs("  ", stdout);
124                 fputs(b->str, stdout);
125                 fputc('\n', stdout);
126                 n = b->next;
127                 free(b->str);
128                 free(b);
129         }
130         output_list = NULL;
131         output_end = NULL;
132 }
133
134 static void output_commit_title(struct commit *commit)
135 {
136         int i;
137         flush_output();
138         for (i = call_depth; i--;)
139                 fputs("  ", stdout);
140         if (commit->util)
141                 printf("virtual %s\n", (char *)commit->util);
142         else {
143                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
144                 if (parse_commit(commit) != 0)
145                         printf("(bad commit)\n");
146                 else {
147                         const char *s;
148                         int len;
149                         for (s = commit->buffer; *s; s++)
150                                 if (*s == '\n' && s[1] == '\n') {
151                                         s += 2;
152                                         break;
153                                 }
154                         for (len = 0; s[len] && '\n' != s[len]; len++)
155                                 ; /* do nothing */
156                         printf("%.*s\n", len, s);
157                 }
158         }
159 }
160
161 static void progress_interval(int signum)
162 {
163         progress_update = 1;
164 }
165
166 static void setup_progress_signal(void)
167 {
168         struct sigaction sa;
169         struct itimerval v;
170
171         memset(&sa, 0, sizeof(sa));
172         sa.sa_handler = progress_interval;
173         sigemptyset(&sa.sa_mask);
174         sa.sa_flags = SA_RESTART;
175         sigaction(SIGALRM, &sa, NULL);
176
177         v.it_interval.tv_sec = 1;
178         v.it_interval.tv_usec = 0;
179         v.it_value = v.it_interval;
180         setitimer(ITIMER_REAL, &v, NULL);
181 }
182
183 static void display_progress()
184 {
185         unsigned percent = total_cnt ? merged_cnt * 100 / total_cnt : 0;
186         if (progress_update || percent != last_percent) {
187                 fprintf(stderr, "%4u%% (%u/%u) done\r",
188                         percent, merged_cnt, total_cnt);
189                 progress_update = 0;
190                 last_percent = percent;
191         }
192 }
193
194 static struct cache_entry *make_cache_entry(unsigned int mode,
195                 const unsigned char *sha1, const char *path, int stage, int refresh)
196 {
197         int size, len;
198         struct cache_entry *ce;
199
200         if (!verify_path(path))
201                 return NULL;
202
203         len = strlen(path);
204         size = cache_entry_size(len);
205         ce = xcalloc(1, size);
206
207         hashcpy(ce->sha1, sha1);
208         memcpy(ce->name, path, len);
209         ce->ce_flags = create_ce_flags(len, stage);
210         ce->ce_mode = create_ce_mode(mode);
211
212         if (refresh)
213                 return refresh_cache_entry(ce, 0);
214
215         return ce;
216 }
217
218 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
219                 const char *path, int stage, int refresh, int options)
220 {
221         struct cache_entry *ce;
222         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
223         if (!ce)
224                 return error("cache_addinfo failed: %s", strerror(cache_errno));
225         return add_cache_entry(ce, options);
226 }
227
228 /*
229  * This is a global variable which is used in a number of places but
230  * only written to in the 'merge' function.
231  *
232  * index_only == 1    => Don't leave any non-stage 0 entries in the cache and
233  *                       don't update the working directory.
234  *               0    => Leave unmerged entries in the cache and update
235  *                       the working directory.
236  */
237 static int index_only = 0;
238
239 static int git_merge_trees(int index_only,
240                            struct tree *common,
241                            struct tree *head,
242                            struct tree *merge)
243 {
244         int rc;
245         struct object_list *trees = NULL;
246         struct unpack_trees_options opts;
247
248         memset(&opts, 0, sizeof(opts));
249         if (index_only)
250                 opts.index_only = 1;
251         else
252                 opts.update = 1;
253         opts.merge = 1;
254         opts.head_idx = 2;
255         opts.fn = threeway_merge;
256
257         object_list_append(&common->object, &trees);
258         object_list_append(&head->object, &trees);
259         object_list_append(&merge->object, &trees);
260
261         rc = unpack_trees(trees, &opts);
262         cache_tree_free(&active_cache_tree);
263         return rc;
264 }
265
266 static int unmerged_index(void)
267 {
268         int i;
269         for (i = 0; i < active_nr; i++) {
270                 struct cache_entry *ce = active_cache[i];
271                 if (ce_stage(ce))
272                         return 1;
273         }
274         return 0;
275 }
276
277 static struct tree *git_write_tree(void)
278 {
279         struct tree *result = NULL;
280
281         if (unmerged_index()) {
282                 int i;
283                 output(0, "There are unmerged index entries:");
284                 for (i = 0; i < active_nr; i++) {
285                         struct cache_entry *ce = active_cache[i];
286                         if (ce_stage(ce))
287                                 output(0, "%d %.*s", ce_stage(ce), ce_namelen(ce), ce->name);
288                 }
289                 return NULL;
290         }
291
292         if (!active_cache_tree)
293                 active_cache_tree = cache_tree();
294
295         if (!cache_tree_fully_valid(active_cache_tree) &&
296             cache_tree_update(active_cache_tree,
297                               active_cache, active_nr, 0, 0) < 0)
298                 die("error building trees");
299
300         result = lookup_tree(active_cache_tree->sha1);
301
302         return result;
303 }
304
305 static int save_files_dirs(const unsigned char *sha1,
306                 const char *base, int baselen, const char *path,
307                 unsigned int mode, int stage)
308 {
309         int len = strlen(path);
310         char *newpath = xmalloc(baselen + len + 1);
311         memcpy(newpath, base, baselen);
312         memcpy(newpath + baselen, path, len);
313         newpath[baselen + len] = '\0';
314
315         if (S_ISDIR(mode))
316                 path_list_insert(newpath, &current_directory_set);
317         else
318                 path_list_insert(newpath, &current_file_set);
319         free(newpath);
320
321         return READ_TREE_RECURSIVE;
322 }
323
324 static int get_files_dirs(struct tree *tree)
325 {
326         int n;
327         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs) != 0)
328                 return 0;
329         n = current_file_set.nr + current_directory_set.nr;
330         return n;
331 }
332
333 /*
334  * Returns a index_entry instance which doesn't have to correspond to
335  * a real cache entry in Git's index.
336  */
337 static struct stage_data *insert_stage_data(const char *path,
338                 struct tree *o, struct tree *a, struct tree *b,
339                 struct path_list *entries)
340 {
341         struct path_list_item *item;
342         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
343         get_tree_entry(o->object.sha1, path,
344                         e->stages[1].sha, &e->stages[1].mode);
345         get_tree_entry(a->object.sha1, path,
346                         e->stages[2].sha, &e->stages[2].mode);
347         get_tree_entry(b->object.sha1, path,
348                         e->stages[3].sha, &e->stages[3].mode);
349         item = path_list_insert(path, entries);
350         item->util = e;
351         return e;
352 }
353
354 /*
355  * Create a dictionary mapping file names to stage_data objects. The
356  * dictionary contains one entry for every path with a non-zero stage entry.
357  */
358 static struct path_list *get_unmerged(void)
359 {
360         struct path_list *unmerged = xcalloc(1, sizeof(struct path_list));
361         int i;
362
363         unmerged->strdup_paths = 1;
364         total_cnt += active_nr;
365
366         for (i = 0; i < active_nr; i++, merged_cnt++) {
367                 struct path_list_item *item;
368                 struct stage_data *e;
369                 struct cache_entry *ce = active_cache[i];
370                 if (do_progress)
371                         display_progress();
372                 if (!ce_stage(ce))
373                         continue;
374
375                 item = path_list_lookup(ce->name, unmerged);
376                 if (!item) {
377                         item = path_list_insert(ce->name, unmerged);
378                         item->util = xcalloc(1, sizeof(struct stage_data));
379                 }
380                 e = item->util;
381                 e->stages[ce_stage(ce)].mode = ntohl(ce->ce_mode);
382                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
383         }
384
385         return unmerged;
386 }
387
388 struct rename
389 {
390         struct diff_filepair *pair;
391         struct stage_data *src_entry;
392         struct stage_data *dst_entry;
393         unsigned processed:1;
394 };
395
396 /*
397  * Get information of all renames which occurred between 'o_tree' and
398  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
399  * 'b_tree') to be able to associate the correct cache entries with
400  * the rename information. 'tree' is always equal to either a_tree or b_tree.
401  */
402 static struct path_list *get_renames(struct tree *tree,
403                                         struct tree *o_tree,
404                                         struct tree *a_tree,
405                                         struct tree *b_tree,
406                                         struct path_list *entries)
407 {
408         int i;
409         struct path_list *renames;
410         struct diff_options opts;
411
412         renames = xcalloc(1, sizeof(struct path_list));
413         diff_setup(&opts);
414         opts.recursive = 1;
415         opts.detect_rename = DIFF_DETECT_RENAME;
416         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
417         if (diff_setup_done(&opts) < 0)
418                 die("diff setup failed");
419         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
420         diffcore_std(&opts);
421         for (i = 0; i < diff_queued_diff.nr; ++i) {
422                 struct path_list_item *item;
423                 struct rename *re;
424                 struct diff_filepair *pair = diff_queued_diff.queue[i];
425                 if (pair->status != 'R') {
426                         diff_free_filepair(pair);
427                         continue;
428                 }
429                 re = xmalloc(sizeof(*re));
430                 re->processed = 0;
431                 re->pair = pair;
432                 item = path_list_lookup(re->pair->one->path, entries);
433                 if (!item)
434                         re->src_entry = insert_stage_data(re->pair->one->path,
435                                         o_tree, a_tree, b_tree, entries);
436                 else
437                         re->src_entry = item->util;
438
439                 item = path_list_lookup(re->pair->two->path, entries);
440                 if (!item)
441                         re->dst_entry = insert_stage_data(re->pair->two->path,
442                                         o_tree, a_tree, b_tree, entries);
443                 else
444                         re->dst_entry = item->util;
445                 item = path_list_insert(pair->one->path, renames);
446                 item->util = re;
447         }
448         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
449         diff_queued_diff.nr = 0;
450         diff_flush(&opts);
451         return renames;
452 }
453
454 static int update_stages(const char *path, struct diff_filespec *o,
455                          struct diff_filespec *a, struct diff_filespec *b,
456                          int clear)
457 {
458         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
459         if (clear)
460                 if (remove_file_from_cache(path))
461                         return -1;
462         if (o)
463                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
464                         return -1;
465         if (a)
466                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
467                         return -1;
468         if (b)
469                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
470                         return -1;
471         return 0;
472 }
473
474 static int remove_path(const char *name)
475 {
476         int ret, len;
477         char *slash, *dirs;
478
479         ret = unlink(name);
480         if (ret)
481                 return ret;
482         len = strlen(name);
483         dirs = xmalloc(len+1);
484         memcpy(dirs, name, len);
485         dirs[len] = '\0';
486         while ((slash = strrchr(name, '/'))) {
487                 *slash = '\0';
488                 len = slash - name;
489                 if (rmdir(name) != 0)
490                         break;
491         }
492         free(dirs);
493         return ret;
494 }
495
496 static int remove_file(int clean, const char *path, int no_wd)
497 {
498         int update_cache = index_only || clean;
499         int update_working_directory = !index_only && !no_wd;
500
501         if (update_cache) {
502                 if (remove_file_from_cache(path))
503                         return -1;
504         }
505         if (update_working_directory) {
506                 unlink(path);
507                 if (errno != ENOENT || errno != EISDIR)
508                         return -1;
509                 remove_path(path);
510         }
511         return 0;
512 }
513
514 static char *unique_path(const char *path, const char *branch)
515 {
516         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
517         int suffix = 0;
518         struct stat st;
519         char *p = newpath + strlen(path);
520         strcpy(newpath, path);
521         *(p++) = '~';
522         strcpy(p, branch);
523         for (; *p; ++p)
524                 if ('/' == *p)
525                         *p = '_';
526         while (path_list_has_path(&current_file_set, newpath) ||
527                path_list_has_path(&current_directory_set, newpath) ||
528                lstat(newpath, &st) == 0)
529                 sprintf(p, "_%d", suffix++);
530
531         path_list_insert(newpath, &current_file_set);
532         return newpath;
533 }
534
535 static int mkdir_p(const char *path, unsigned long mode)
536 {
537         /* path points to cache entries, so xstrdup before messing with it */
538         char *buf = xstrdup(path);
539         int result = safe_create_leading_directories(buf);
540         free(buf);
541         return result;
542 }
543
544 static void flush_buffer(int fd, const char *buf, unsigned long size)
545 {
546         while (size > 0) {
547                 long ret = write_in_full(fd, buf, size);
548                 if (ret < 0) {
549                         /* Ignore epipe */
550                         if (errno == EPIPE)
551                                 break;
552                         die("merge-recursive: %s", strerror(errno));
553                 } else if (!ret) {
554                         die("merge-recursive: disk full?");
555                 }
556                 size -= ret;
557                 buf += ret;
558         }
559 }
560
561 static void update_file_flags(const unsigned char *sha,
562                               unsigned mode,
563                               const char *path,
564                               int update_cache,
565                               int update_wd)
566 {
567         if (index_only)
568                 update_wd = 0;
569
570         if (update_wd) {
571                 enum object_type type;
572                 void *buf;
573                 unsigned long size;
574
575                 buf = read_sha1_file(sha, &type, &size);
576                 if (!buf)
577                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
578                 if (type != OBJ_BLOB)
579                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
580
581                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
582                         int fd;
583                         if (mkdir_p(path, 0777))
584                                 die("failed to create path %s: %s", path, strerror(errno));
585                         unlink(path);
586                         if (mode & 0100)
587                                 mode = 0777;
588                         else
589                                 mode = 0666;
590                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
591                         if (fd < 0)
592                                 die("failed to open %s: %s", path, strerror(errno));
593                         flush_buffer(fd, buf, size);
594                         close(fd);
595                 } else if (S_ISLNK(mode)) {
596                         char *lnk = xmalloc(size + 1);
597                         memcpy(lnk, buf, size);
598                         lnk[size] = '\0';
599                         mkdir_p(path, 0777);
600                         unlink(path);
601                         symlink(lnk, path);
602                         free(lnk);
603                 } else
604                         die("do not know what to do with %06o %s '%s'",
605                             mode, sha1_to_hex(sha), path);
606         }
607         if (update_cache)
608                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
609 }
610
611 static void update_file(int clean,
612                         const unsigned char *sha,
613                         unsigned mode,
614                         const char *path)
615 {
616         update_file_flags(sha, mode, path, index_only || clean, !index_only);
617 }
618
619 /* Low level file merging, update and removal */
620
621 struct merge_file_info
622 {
623         unsigned char sha[20];
624         unsigned mode;
625         unsigned clean:1,
626                  merge:1;
627 };
628
629 static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
630 {
631         unsigned long size;
632         enum object_type type;
633
634         if (!hashcmp(sha1, null_sha1)) {
635                 mm->ptr = xstrdup("");
636                 mm->size = 0;
637                 return;
638         }
639
640         mm->ptr = read_sha1_file(sha1, &type, &size);
641         if (!mm->ptr || type != OBJ_BLOB)
642                 die("unable to read blob object %s", sha1_to_hex(sha1));
643         mm->size = size;
644 }
645
646 static struct merge_file_info merge_file(struct diff_filespec *o,
647                 struct diff_filespec *a, struct diff_filespec *b,
648                 const char *branch1, const char *branch2)
649 {
650         struct merge_file_info result;
651         result.merge = 0;
652         result.clean = 1;
653
654         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
655                 result.clean = 0;
656                 if (S_ISREG(a->mode)) {
657                         result.mode = a->mode;
658                         hashcpy(result.sha, a->sha1);
659                 } else {
660                         result.mode = b->mode;
661                         hashcpy(result.sha, b->sha1);
662                 }
663         } else {
664                 if (!sha_eq(a->sha1, o->sha1) && !sha_eq(b->sha1, o->sha1))
665                         result.merge = 1;
666
667                 result.mode = a->mode == o->mode ? b->mode: a->mode;
668
669                 if (sha_eq(a->sha1, o->sha1))
670                         hashcpy(result.sha, b->sha1);
671                 else if (sha_eq(b->sha1, o->sha1))
672                         hashcpy(result.sha, a->sha1);
673                 else if (S_ISREG(a->mode)) {
674                         mmfile_t orig, src1, src2;
675                         mmbuffer_t result_buf;
676                         xpparam_t xpp;
677                         char *name1, *name2;
678                         int merge_status;
679
680                         name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
681                         name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
682
683                         fill_mm(o->sha1, &orig);
684                         fill_mm(a->sha1, &src1);
685                         fill_mm(b->sha1, &src2);
686
687                         memset(&xpp, 0, sizeof(xpp));
688                         merge_status = xdl_merge(&orig,
689                                                  &src1, name1,
690                                                  &src2, name2,
691                                                  &xpp, XDL_MERGE_ZEALOUS,
692                                                  &result_buf);
693                         free(name1);
694                         free(name2);
695                         free(orig.ptr);
696                         free(src1.ptr);
697                         free(src2.ptr);
698
699                         if ((merge_status < 0) || !result_buf.ptr)
700                                 die("Failed to execute internal merge");
701
702                         if (write_sha1_file(result_buf.ptr, result_buf.size,
703                                             blob_type, result.sha))
704                                 die("Unable to add %s to database",
705                                     a->path);
706
707                         free(result_buf.ptr);
708                         result.clean = (merge_status == 0);
709                 } else {
710                         if (!(S_ISLNK(a->mode) || S_ISLNK(b->mode)))
711                                 die("cannot merge modes?");
712
713                         hashcpy(result.sha, a->sha1);
714
715                         if (!sha_eq(a->sha1, b->sha1))
716                                 result.clean = 0;
717                 }
718         }
719
720         return result;
721 }
722
723 static void conflict_rename_rename(struct rename *ren1,
724                                    const char *branch1,
725                                    struct rename *ren2,
726                                    const char *branch2)
727 {
728         char *del[2];
729         int delp = 0;
730         const char *ren1_dst = ren1->pair->two->path;
731         const char *ren2_dst = ren2->pair->two->path;
732         const char *dst_name1 = ren1_dst;
733         const char *dst_name2 = ren2_dst;
734         if (path_list_has_path(&current_directory_set, ren1_dst)) {
735                 dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
736                 output(1, "%s is a directory in %s added as %s instead",
737                        ren1_dst, branch2, dst_name1);
738                 remove_file(0, ren1_dst, 0);
739         }
740         if (path_list_has_path(&current_directory_set, ren2_dst)) {
741                 dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
742                 output(1, "%s is a directory in %s added as %s instead",
743                        ren2_dst, branch1, dst_name2);
744                 remove_file(0, ren2_dst, 0);
745         }
746         if (index_only) {
747                 remove_file_from_cache(dst_name1);
748                 remove_file_from_cache(dst_name2);
749                 /*
750                  * Uncomment to leave the conflicting names in the resulting tree
751                  *
752                  * update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
753                  * update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
754                  */
755         } else {
756                 update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
757                 update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
758         }
759         while (delp--)
760                 free(del[delp]);
761 }
762
763 static void conflict_rename_dir(struct rename *ren1,
764                                 const char *branch1)
765 {
766         char *new_path = unique_path(ren1->pair->two->path, branch1);
767         output(1, "Renamed %s to %s instead", ren1->pair->one->path, new_path);
768         remove_file(0, ren1->pair->two->path, 0);
769         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
770         free(new_path);
771 }
772
773 static void conflict_rename_rename_2(struct rename *ren1,
774                                      const char *branch1,
775                                      struct rename *ren2,
776                                      const char *branch2)
777 {
778         char *new_path1 = unique_path(ren1->pair->two->path, branch1);
779         char *new_path2 = unique_path(ren2->pair->two->path, branch2);
780         output(1, "Renamed %s to %s and %s to %s instead",
781                ren1->pair->one->path, new_path1,
782                ren2->pair->one->path, new_path2);
783         remove_file(0, ren1->pair->two->path, 0);
784         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
785         update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
786         free(new_path2);
787         free(new_path1);
788 }
789
790 static int process_renames(struct path_list *a_renames,
791                            struct path_list *b_renames,
792                            const char *a_branch,
793                            const char *b_branch)
794 {
795         int clean_merge = 1, i, j;
796         struct path_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
797         const struct rename *sre;
798
799         for (i = 0; i < a_renames->nr; i++) {
800                 sre = a_renames->items[i].util;
801                 path_list_insert(sre->pair->two->path, &a_by_dst)->util
802                         = sre->dst_entry;
803         }
804         for (i = 0; i < b_renames->nr; i++) {
805                 sre = b_renames->items[i].util;
806                 path_list_insert(sre->pair->two->path, &b_by_dst)->util
807                         = sre->dst_entry;
808         }
809
810         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
811                 int compare;
812                 char *src;
813                 struct path_list *renames1, *renames2, *renames2Dst;
814                 struct rename *ren1 = NULL, *ren2 = NULL;
815                 const char *branch1, *branch2;
816                 const char *ren1_src, *ren1_dst;
817
818                 if (i >= a_renames->nr) {
819                         compare = 1;
820                         ren2 = b_renames->items[j++].util;
821                 } else if (j >= b_renames->nr) {
822                         compare = -1;
823                         ren1 = a_renames->items[i++].util;
824                 } else {
825                         compare = strcmp(a_renames->items[i].path,
826                                         b_renames->items[j].path);
827                         if (compare <= 0)
828                                 ren1 = a_renames->items[i++].util;
829                         if (compare >= 0)
830                                 ren2 = b_renames->items[j++].util;
831                 }
832
833                 /* TODO: refactor, so that 1/2 are not needed */
834                 if (ren1) {
835                         renames1 = a_renames;
836                         renames2 = b_renames;
837                         renames2Dst = &b_by_dst;
838                         branch1 = a_branch;
839                         branch2 = b_branch;
840                 } else {
841                         struct rename *tmp;
842                         renames1 = b_renames;
843                         renames2 = a_renames;
844                         renames2Dst = &a_by_dst;
845                         branch1 = b_branch;
846                         branch2 = a_branch;
847                         tmp = ren2;
848                         ren2 = ren1;
849                         ren1 = tmp;
850                 }
851                 src = ren1->pair->one->path;
852
853                 ren1->dst_entry->processed = 1;
854                 ren1->src_entry->processed = 1;
855
856                 if (ren1->processed)
857                         continue;
858                 ren1->processed = 1;
859
860                 ren1_src = ren1->pair->one->path;
861                 ren1_dst = ren1->pair->two->path;
862
863                 if (ren2) {
864                         const char *ren2_src = ren2->pair->one->path;
865                         const char *ren2_dst = ren2->pair->two->path;
866                         /* Renamed in 1 and renamed in 2 */
867                         if (strcmp(ren1_src, ren2_src) != 0)
868                                 die("ren1.src != ren2.src");
869                         ren2->dst_entry->processed = 1;
870                         ren2->processed = 1;
871                         if (strcmp(ren1_dst, ren2_dst) != 0) {
872                                 clean_merge = 0;
873                                 output(1, "CONFLICT (rename/rename): "
874                                        "Rename \"%s\"->\"%s\" in branch \"%s\" "
875                                        "rename \"%s\"->\"%s\" in \"%s\"%s",
876                                        src, ren1_dst, branch1,
877                                        src, ren2_dst, branch2,
878                                        index_only ? " (left unresolved)": "");
879                                 if (index_only) {
880                                         remove_file_from_cache(src);
881                                         update_file(0, ren1->pair->one->sha1,
882                                                     ren1->pair->one->mode, src);
883                                 }
884                                 conflict_rename_rename(ren1, branch1, ren2, branch2);
885                         } else {
886                                 struct merge_file_info mfi;
887                                 remove_file(1, ren1_src, 1);
888                                 mfi = merge_file(ren1->pair->one,
889                                                  ren1->pair->two,
890                                                  ren2->pair->two,
891                                                  branch1,
892                                                  branch2);
893                                 if (mfi.merge || !mfi.clean)
894                                         output(1, "Renamed %s->%s", src, ren1_dst);
895
896                                 if (mfi.merge)
897                                         output(2, "Auto-merged %s", ren1_dst);
898
899                                 if (!mfi.clean) {
900                                         output(1, "CONFLICT (content): merge conflict in %s",
901                                                ren1_dst);
902                                         clean_merge = 0;
903
904                                         if (!index_only)
905                                                 update_stages(ren1_dst,
906                                                               ren1->pair->one,
907                                                               ren1->pair->two,
908                                                               ren2->pair->two,
909                                                               1 /* clear */);
910                                 }
911                                 update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
912                         }
913                 } else {
914                         /* Renamed in 1, maybe changed in 2 */
915                         struct path_list_item *item;
916                         /* we only use sha1 and mode of these */
917                         struct diff_filespec src_other, dst_other;
918                         int try_merge, stage = a_renames == renames1 ? 3: 2;
919
920                         remove_file(1, ren1_src, index_only || stage == 3);
921
922                         hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
923                         src_other.mode = ren1->src_entry->stages[stage].mode;
924                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
925                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
926
927                         try_merge = 0;
928
929                         if (path_list_has_path(&current_directory_set, ren1_dst)) {
930                                 clean_merge = 0;
931                                 output(1, "CONFLICT (rename/directory): Renamed %s->%s in %s "
932                                        " directory %s added in %s",
933                                        ren1_src, ren1_dst, branch1,
934                                        ren1_dst, branch2);
935                                 conflict_rename_dir(ren1, branch1);
936                         } else if (sha_eq(src_other.sha1, null_sha1)) {
937                                 clean_merge = 0;
938                                 output(1, "CONFLICT (rename/delete): Renamed %s->%s in %s "
939                                        "and deleted in %s",
940                                        ren1_src, ren1_dst, branch1,
941                                        branch2);
942                                 update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
943                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
944                                 const char *new_path;
945                                 clean_merge = 0;
946                                 try_merge = 1;
947                                 output(1, "CONFLICT (rename/add): Renamed %s->%s in %s. "
948                                        "%s added in %s",
949                                        ren1_src, ren1_dst, branch1,
950                                        ren1_dst, branch2);
951                                 new_path = unique_path(ren1_dst, branch2);
952                                 output(1, "Added as %s instead", new_path);
953                                 update_file(0, dst_other.sha1, dst_other.mode, new_path);
954                         } else if ((item = path_list_lookup(ren1_dst, renames2Dst))) {
955                                 ren2 = item->util;
956                                 clean_merge = 0;
957                                 ren2->processed = 1;
958                                 output(1, "CONFLICT (rename/rename): Renamed %s->%s in %s. "
959                                        "Renamed %s->%s in %s",
960                                        ren1_src, ren1_dst, branch1,
961                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
962                                 conflict_rename_rename_2(ren1, branch1, ren2, branch2);
963                         } else
964                                 try_merge = 1;
965
966                         if (try_merge) {
967                                 struct diff_filespec *o, *a, *b;
968                                 struct merge_file_info mfi;
969                                 src_other.path = (char *)ren1_src;
970
971                                 o = ren1->pair->one;
972                                 if (a_renames == renames1) {
973                                         a = ren1->pair->two;
974                                         b = &src_other;
975                                 } else {
976                                         b = ren1->pair->two;
977                                         a = &src_other;
978                                 }
979                                 mfi = merge_file(o, a, b,
980                                                 a_branch, b_branch);
981
982                                 if (mfi.merge || !mfi.clean)
983                                         output(1, "Renamed %s => %s", ren1_src, ren1_dst);
984                                 if (mfi.merge)
985                                         output(2, "Auto-merged %s", ren1_dst);
986                                 if (!mfi.clean) {
987                                         output(1, "CONFLICT (rename/modify): Merge conflict in %s",
988                                                ren1_dst);
989                                         clean_merge = 0;
990
991                                         if (!index_only)
992                                                 update_stages(ren1_dst,
993                                                                 o, a, b, 1);
994                                 }
995                                 update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
996                         }
997                 }
998         }
999         path_list_clear(&a_by_dst, 0);
1000         path_list_clear(&b_by_dst, 0);
1001
1002         return clean_merge;
1003 }
1004
1005 static unsigned char *has_sha(const unsigned char *sha)
1006 {
1007         return is_null_sha1(sha) ? NULL: (unsigned char *)sha;
1008 }
1009
1010 /* Per entry merge function */
1011 static int process_entry(const char *path, struct stage_data *entry,
1012                          const char *branch1,
1013                          const char *branch2)
1014 {
1015         /*
1016         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1017         print_index_entry("\tpath: ", entry);
1018         */
1019         int clean_merge = 1;
1020         unsigned char *o_sha = has_sha(entry->stages[1].sha);
1021         unsigned char *a_sha = has_sha(entry->stages[2].sha);
1022         unsigned char *b_sha = has_sha(entry->stages[3].sha);
1023         unsigned o_mode = entry->stages[1].mode;
1024         unsigned a_mode = entry->stages[2].mode;
1025         unsigned b_mode = entry->stages[3].mode;
1026
1027         if (o_sha && (!a_sha || !b_sha)) {
1028                 /* Case A: Deleted in one */
1029                 if ((!a_sha && !b_sha) ||
1030                     (sha_eq(a_sha, o_sha) && !b_sha) ||
1031                     (!a_sha && sha_eq(b_sha, o_sha))) {
1032                         /* Deleted in both or deleted in one and
1033                          * unchanged in the other */
1034                         if (a_sha)
1035                                 output(2, "Removed %s", path);
1036                         /* do not touch working file if it did not exist */
1037                         remove_file(1, path, !a_sha);
1038                 } else {
1039                         /* Deleted in one and changed in the other */
1040                         clean_merge = 0;
1041                         if (!a_sha) {
1042                                 output(1, "CONFLICT (delete/modify): %s deleted in %s "
1043                                        "and modified in %s. Version %s of %s left in tree.",
1044                                        path, branch1,
1045                                        branch2, branch2, path);
1046                                 update_file(0, b_sha, b_mode, path);
1047                         } else {
1048                                 output(1, "CONFLICT (delete/modify): %s deleted in %s "
1049                                        "and modified in %s. Version %s of %s left in tree.",
1050                                        path, branch2,
1051                                        branch1, branch1, path);
1052                                 update_file(0, a_sha, a_mode, path);
1053                         }
1054                 }
1055
1056         } else if ((!o_sha && a_sha && !b_sha) ||
1057                    (!o_sha && !a_sha && b_sha)) {
1058                 /* Case B: Added in one. */
1059                 const char *add_branch;
1060                 const char *other_branch;
1061                 unsigned mode;
1062                 const unsigned char *sha;
1063                 const char *conf;
1064
1065                 if (a_sha) {
1066                         add_branch = branch1;
1067                         other_branch = branch2;
1068                         mode = a_mode;
1069                         sha = a_sha;
1070                         conf = "file/directory";
1071                 } else {
1072                         add_branch = branch2;
1073                         other_branch = branch1;
1074                         mode = b_mode;
1075                         sha = b_sha;
1076                         conf = "directory/file";
1077                 }
1078                 if (path_list_has_path(&current_directory_set, path)) {
1079                         const char *new_path = unique_path(path, add_branch);
1080                         clean_merge = 0;
1081                         output(1, "CONFLICT (%s): There is a directory with name %s in %s. "
1082                                "Added %s as %s",
1083                                conf, path, other_branch, path, new_path);
1084                         remove_file(0, path, 0);
1085                         update_file(0, sha, mode, new_path);
1086                 } else {
1087                         output(2, "Added %s", path);
1088                         update_file(1, sha, mode, path);
1089                 }
1090         } else if (a_sha && b_sha) {
1091                 /* Case C: Added in both (check for same permissions) and */
1092                 /* case D: Modified in both, but differently. */
1093                 const char *reason = "content";
1094                 struct merge_file_info mfi;
1095                 struct diff_filespec o, a, b;
1096
1097                 if (!o_sha) {
1098                         reason = "add/add";
1099                         o_sha = (unsigned char *)null_sha1;
1100                 }
1101                 output(2, "Auto-merged %s", path);
1102                 o.path = a.path = b.path = (char *)path;
1103                 hashcpy(o.sha1, o_sha);
1104                 o.mode = o_mode;
1105                 hashcpy(a.sha1, a_sha);
1106                 a.mode = a_mode;
1107                 hashcpy(b.sha1, b_sha);
1108                 b.mode = b_mode;
1109
1110                 mfi = merge_file(&o, &a, &b,
1111                                  branch1, branch2);
1112
1113                 if (mfi.clean)
1114                         update_file(1, mfi.sha, mfi.mode, path);
1115                 else {
1116                         clean_merge = 0;
1117                         output(1, "CONFLICT (%s): Merge conflict in %s",
1118                                         reason, path);
1119
1120                         if (index_only)
1121                                 update_file(0, mfi.sha, mfi.mode, path);
1122                         else
1123                                 update_file_flags(mfi.sha, mfi.mode, path,
1124                                               0 /* update_cache */, 1 /* update_working_directory */);
1125                 }
1126         } else
1127                 die("Fatal merge failure, shouldn't happen.");
1128
1129         return clean_merge;
1130 }
1131
1132 static int merge_trees(struct tree *head,
1133                        struct tree *merge,
1134                        struct tree *common,
1135                        const char *branch1,
1136                        const char *branch2,
1137                        struct tree **result)
1138 {
1139         int code, clean;
1140         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1141                 output(0, "Already uptodate!");
1142                 *result = head;
1143                 return 1;
1144         }
1145
1146         code = git_merge_trees(index_only, common, head, merge);
1147
1148         if (code != 0)
1149                 die("merging of trees %s and %s failed",
1150                     sha1_to_hex(head->object.sha1),
1151                     sha1_to_hex(merge->object.sha1));
1152
1153         if (unmerged_index()) {
1154                 struct path_list *entries, *re_head, *re_merge;
1155                 int i;
1156                 path_list_clear(&current_file_set, 1);
1157                 path_list_clear(&current_directory_set, 1);
1158                 get_files_dirs(head);
1159                 get_files_dirs(merge);
1160
1161                 entries = get_unmerged();
1162                 re_head  = get_renames(head, common, head, merge, entries);
1163                 re_merge = get_renames(merge, common, head, merge, entries);
1164                 clean = process_renames(re_head, re_merge,
1165                                 branch1, branch2);
1166                 total_cnt += entries->nr;
1167                 for (i = 0; i < entries->nr; i++, merged_cnt++) {
1168                         const char *path = entries->items[i].path;
1169                         struct stage_data *e = entries->items[i].util;
1170                         if (!e->processed
1171                                 && !process_entry(path, e, branch1, branch2))
1172                                 clean = 0;
1173                         if (do_progress)
1174                                 display_progress();
1175                 }
1176
1177                 path_list_clear(re_merge, 0);
1178                 path_list_clear(re_head, 0);
1179                 path_list_clear(entries, 1);
1180
1181         }
1182         else
1183                 clean = 1;
1184
1185         if (index_only)
1186                 *result = git_write_tree();
1187
1188         return clean;
1189 }
1190
1191 static struct commit_list *reverse_commit_list(struct commit_list *list)
1192 {
1193         struct commit_list *next = NULL, *current, *backup;
1194         for (current = list; current; current = backup) {
1195                 backup = current->next;
1196                 current->next = next;
1197                 next = current;
1198         }
1199         return next;
1200 }
1201
1202 /*
1203  * Merge the commits h1 and h2, return the resulting virtual
1204  * commit object and a flag indicating the cleanness of the merge.
1205  */
1206 static int merge(struct commit *h1,
1207                  struct commit *h2,
1208                  const char *branch1,
1209                  const char *branch2,
1210                  struct commit_list *ca,
1211                  struct commit **result)
1212 {
1213         struct commit_list *iter;
1214         struct commit *merged_common_ancestors;
1215         struct tree *mrtree;
1216         int clean;
1217
1218         if (show(4)) {
1219                 output(4, "Merging:");
1220                 output_commit_title(h1);
1221                 output_commit_title(h2);
1222         }
1223
1224         if (!ca) {
1225                 ca = get_merge_bases(h1, h2, 1);
1226                 ca = reverse_commit_list(ca);
1227         }
1228
1229         if (show(5)) {
1230                 output(5, "found %u common ancestor(s):", commit_list_count(ca));
1231                 for (iter = ca; iter; iter = iter->next)
1232                         output_commit_title(iter->item);
1233         }
1234
1235         merged_common_ancestors = pop_commit(&ca);
1236         if (merged_common_ancestors == NULL) {
1237                 /* if there is no common ancestor, make an empty tree */
1238                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1239
1240                 tree->object.parsed = 1;
1241                 tree->object.type = OBJ_TREE;
1242                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1243                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1244         }
1245
1246         for (iter = ca; iter; iter = iter->next) {
1247                 call_depth++;
1248                 /*
1249                  * When the merge fails, the result contains files
1250                  * with conflict markers. The cleanness flag is
1251                  * ignored, it was never actually used, as result of
1252                  * merge_trees has always overwritten it: the committed
1253                  * "conflicts" were already resolved.
1254                  */
1255                 discard_cache();
1256                 merge(merged_common_ancestors, iter->item,
1257                       "Temporary merge branch 1",
1258                       "Temporary merge branch 2",
1259                       NULL,
1260                       &merged_common_ancestors);
1261                 call_depth--;
1262
1263                 if (!merged_common_ancestors)
1264                         die("merge returned no commit");
1265         }
1266
1267         discard_cache();
1268         if (!call_depth) {
1269                 read_cache();
1270                 index_only = 0;
1271         } else
1272                 index_only = 1;
1273
1274         clean = merge_trees(h1->tree, h2->tree, merged_common_ancestors->tree,
1275                             branch1, branch2, &mrtree);
1276
1277         if (index_only) {
1278                 *result = make_virtual_commit(mrtree, "merged tree");
1279                 commit_list_insert(h1, &(*result)->parents);
1280                 commit_list_insert(h2, &(*result)->parents->next);
1281         }
1282         if (!call_depth && do_progress) {
1283                 /* Make sure we end at 100% */
1284                 if (!total_cnt)
1285                         total_cnt = 1;
1286                 merged_cnt = total_cnt;
1287                 progress_update = 1;
1288                 display_progress();
1289                 fputc('\n', stderr);
1290         }
1291         flush_output();
1292         return clean;
1293 }
1294
1295 static const char *better_branch_name(const char *branch)
1296 {
1297         static char githead_env[8 + 40 + 1];
1298         char *name;
1299
1300         if (strlen(branch) != 40)
1301                 return branch;
1302         sprintf(githead_env, "GITHEAD_%s", branch);
1303         name = getenv(githead_env);
1304         return name ? name : branch;
1305 }
1306
1307 static struct commit *get_ref(const char *ref)
1308 {
1309         unsigned char sha1[20];
1310         struct object *object;
1311
1312         if (get_sha1(ref, sha1))
1313                 die("Could not resolve ref '%s'", ref);
1314         object = deref_tag(parse_object(sha1), ref, strlen(ref));
1315         if (object->type == OBJ_TREE)
1316                 return make_virtual_commit((struct tree*)object,
1317                         better_branch_name(ref));
1318         if (object->type != OBJ_COMMIT)
1319                 return NULL;
1320         if (parse_commit((struct commit *)object))
1321                 die("Could not parse commit '%s'", sha1_to_hex(object->sha1));
1322         return (struct commit *)object;
1323 }
1324
1325 static int merge_config(const char *var, const char *value)
1326 {
1327         if (!strcasecmp(var, "merge.verbosity")) {
1328                 verbosity = git_config_int(var, value);
1329                 return 0;
1330         }
1331         return git_default_config(var, value);
1332 }
1333
1334 int main(int argc, char *argv[])
1335 {
1336         static const char *bases[20];
1337         static unsigned bases_count = 0;
1338         int i, clean;
1339         const char *branch1, *branch2;
1340         struct commit *result, *h1, *h2;
1341         struct commit_list *ca = NULL;
1342         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1343         int index_fd;
1344
1345         git_config(merge_config);
1346         if (getenv("GIT_MERGE_VERBOSITY"))
1347                 verbosity = strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1348
1349         if (argc < 4)
1350                 die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
1351
1352         for (i = 1; i < argc; ++i) {
1353                 if (!strcmp(argv[i], "--"))
1354                         break;
1355                 if (bases_count < sizeof(bases)/sizeof(*bases))
1356                         bases[bases_count++] = argv[i];
1357         }
1358         if (argc - i != 3) /* "--" "<head>" "<remote>" */
1359                 die("Not handling anything other than two heads merge.");
1360         if (verbosity >= 5) {
1361                 buffer_output = 0;
1362                 do_progress = 0;
1363         }
1364         else
1365                 do_progress = isatty(1);
1366
1367         branch1 = argv[++i];
1368         branch2 = argv[++i];
1369
1370         h1 = get_ref(branch1);
1371         h2 = get_ref(branch2);
1372
1373         branch1 = better_branch_name(branch1);
1374         branch2 = better_branch_name(branch2);
1375
1376         if (do_progress)
1377                 setup_progress_signal();
1378         if (show(3))
1379                 printf("Merging %s with %s\n", branch1, branch2);
1380
1381         index_fd = hold_lock_file_for_update(lock, get_index_file(), 1);
1382
1383         for (i = 0; i < bases_count; i++) {
1384                 struct commit *ancestor = get_ref(bases[i]);
1385                 ca = commit_list_insert(ancestor, &ca);
1386         }
1387         clean = merge(h1, h2, branch1, branch2, ca, &result);
1388
1389         if (active_cache_changed &&
1390             (write_cache(index_fd, active_cache, active_nr) ||
1391              close(index_fd) || commit_lock_file(lock)))
1392                         die ("unable to write %s", get_index_file());
1393
1394         return clean ? 0: 1;
1395 }