4 static const char merge_tree_usage[] = "git-merge-tree <base-tree> <branch1> <branch2>";
5 static int resolve_directories = 1;
7 static void merge_trees(struct tree_desc t[3], const char *base);
9 static void *fill_tree_descriptor(struct tree_desc *desc, const unsigned char *sha1)
11 unsigned long size = 0;
15 buf = read_object_with_reference(sha1, "tree", &size, NULL);
17 die("unable to read tree %s", sha1_to_hex(sha1));
25 const unsigned char *sha1;
31 static void entry_clear(struct name_entry *a)
33 memset(a, 0, sizeof(*a));
36 static int entry_compare(struct name_entry *a, struct name_entry *b)
38 return base_name_compare(
39 a->path, a->pathlen, a->mode,
40 b->path, b->pathlen, b->mode);
43 static void entry_extract(struct tree_desc *t, struct name_entry *a)
45 a->sha1 = tree_entry_extract(t, &a->path, &a->mode);
46 a->pathlen = strlen(a->path);
49 /* An empty entry never compares same, not even to another empty entry */
50 static int same_entry(struct name_entry *a, struct name_entry *b)
54 !memcmp(a->sha1, b->sha1, 20) &&
58 static const char *sha1_to_hex_zero(const unsigned char *sha1)
61 return sha1_to_hex(sha1);
62 return "0000000000000000000000000000000000000000";
65 static void resolve(const char *base, struct name_entry *branch1, struct name_entry *result)
67 char branch1_sha1[50];
69 /* If it's already branch1, don't bother showing it */
72 memcpy(branch1_sha1, sha1_to_hex_zero(branch1->sha1), 41);
74 printf("0 %06o->%06o %s->%s %s%s\n",
75 branch1->mode, result->mode,
76 branch1_sha1, sha1_to_hex_zero(result->sha1),
80 static int unresolved_directory(const char *base, struct name_entry n[3])
85 struct tree_desc t[3];
86 void *buf0, *buf1, *buf2;
88 if (!resolve_directories)
96 if (!S_ISDIR(p->mode))
98 baselen = strlen(base);
99 newbase = xmalloc(baselen + p->pathlen + 2);
100 memcpy(newbase, base, baselen);
101 memcpy(newbase + baselen, p->path, p->pathlen);
102 memcpy(newbase + baselen + p->pathlen, "/", 2);
104 buf0 = fill_tree_descriptor(t+0, n[0].sha1);
105 buf1 = fill_tree_descriptor(t+1, n[1].sha1);
106 buf2 = fill_tree_descriptor(t+2, n[2].sha1);
107 merge_trees(t, newbase);
116 static void unresolved(const char *base, struct name_entry n[3])
118 if (unresolved_directory(base, n))
121 printf("1 %06o %s %s%s\n", n[0].mode, sha1_to_hex(n[0].sha1), base, n[0].path);
123 printf("2 %06o %s %s%s\n", n[1].mode, sha1_to_hex(n[1].sha1), base, n[1].path);
125 printf("3 %06o %s %s%s\n", n[2].mode, sha1_to_hex(n[2].sha1), base, n[2].path);
129 * Merge two trees together (t[1] and t[2]), using a common base (t[0])
132 * This walks the (sorted) trees in lock-step, checking every possible
133 * name. Note that directories automatically sort differently from other
134 * files (see "base_name_compare"), so you'll never see file/directory
135 * conflicts, because they won't ever compare the same.
137 * IOW, if a directory changes to a filename, it will automatically be
138 * seen as the directory going away, and the filename being created.
140 * Think of this as a three-way diff.
142 * The output will be either:
144 * "0 mode sha1 filename"
145 * NOTE NOTE NOTE! FIXME! We really really need to walk the index
146 * in parallel with this too!
149 * "1 mode sha1 filename"
150 * "2 mode sha1 filename"
151 * "3 mode sha1 filename"
152 * where not all of the 1/2/3 lines may exist, of course.
154 * The successful merge rules are the same as for the three-way merge
157 static void merge_trees(struct tree_desc t[3], const char *base)
160 struct name_entry entry[3];
161 unsigned int mask = 0;
165 for (i = 0; i < 3; i++) {
168 entry_extract(t+i, entry+i);
170 int cmp = entry_compare(entry+i, entry+last);
173 * Is the new name bigger than the old one?
179 * Is the new name smaller than the old one?
180 * Ignore all old ones
192 * Update the tree entries we've walked, and clear
193 * all the unused name-entries.
195 for (i = 0; i < 3; i++) {
196 if (mask & (1u << i)) {
197 update_tree_entry(t+i);
200 entry_clear(entry + i);
204 if (same_entry(entry+1, entry+2)) {
206 resolve(base, NULL, entry+1);
211 if (same_entry(entry+0, entry+1)) {
212 if (entry[2].sha1 && !S_ISDIR(entry[2].mode)) {
213 resolve(base, entry+1, entry+2);
218 if (same_entry(entry+0, entry+2)) {
219 if (entry[1].sha1 && !S_ISDIR(entry[1].mode)) {
220 resolve(base, NULL, entry+1);
225 unresolved(base, entry);
229 static void *get_tree_descriptor(struct tree_desc *desc, const char *rev)
231 unsigned char sha1[20];
234 if (get_sha1(rev, sha1) < 0)
235 die("unknown rev %s", rev);
236 buf = fill_tree_descriptor(desc, sha1);
238 die("%s is not a tree", rev);
242 int main(int argc, char **argv)
244 struct tree_desc t[3];
245 void *buf1, *buf2, *buf3;
248 usage(merge_tree_usage);
250 buf1 = get_tree_descriptor(t+0, argv[1]);
251 buf2 = get_tree_descriptor(t+1, argv[2]);
252 buf3 = get_tree_descriptor(t+2, argv[3]);