Merge branch 'maint'
[git/debian.git] / builtin / merge-tree.c
blob61cbde4094bf27ea9dfaba158233ba7f4613f2ee
1 #include "builtin.h"
2 #include "tree-walk.h"
3 #include "xdiff-interface.h"
4 #include "blob.h"
5 #include "exec_cmd.h"
6 #include "merge-blobs.h"
8 static const char merge_tree_usage[] = "git merge-tree <base-tree> <branch1> <branch2>";
10 struct merge_list {
11 struct merge_list *next;
12 struct merge_list *link; /* other stages for this object */
14 unsigned int stage : 2;
15 unsigned int mode;
16 const char *path;
17 struct blob *blob;
20 static struct merge_list *merge_result, **merge_result_end = &merge_result;
22 static void add_merge_entry(struct merge_list *entry)
24 *merge_result_end = entry;
25 merge_result_end = &entry->next;
28 static void merge_trees_recursive(struct tree_desc t[3], const char *base, int df_conflict);
30 static const char *explanation(struct merge_list *entry)
32 switch (entry->stage) {
33 case 0:
34 return "merged";
35 case 3:
36 return "added in remote";
37 case 2:
38 if (entry->link)
39 return "added in both";
40 return "added in local";
43 /* Existed in base */
44 entry = entry->link;
45 if (!entry)
46 return "removed in both";
48 if (entry->link)
49 return "changed in both";
51 if (entry->stage == 3)
52 return "removed in local";
53 return "removed in remote";
56 static void *result(struct merge_list *entry, unsigned long *size)
58 enum object_type type;
59 struct blob *base, *our, *their;
60 const char *path = entry->path;
62 if (!entry->stage)
63 return read_sha1_file(entry->blob->object.sha1, &type, size);
64 base = NULL;
65 if (entry->stage == 1) {
66 base = entry->blob;
67 entry = entry->link;
69 our = NULL;
70 if (entry && entry->stage == 2) {
71 our = entry->blob;
72 entry = entry->link;
74 their = NULL;
75 if (entry)
76 their = entry->blob;
77 return merge_blobs(path, base, our, their, size);
80 static void *origin(struct merge_list *entry, unsigned long *size)
82 enum object_type type;
83 while (entry) {
84 if (entry->stage == 2)
85 return read_sha1_file(entry->blob->object.sha1, &type, size);
86 entry = entry->link;
88 return NULL;
91 static int show_outf(void *priv_, mmbuffer_t *mb, int nbuf)
93 int i;
94 for (i = 0; i < nbuf; i++)
95 printf("%.*s", (int) mb[i].size, mb[i].ptr);
96 return 0;
99 static void show_diff(struct merge_list *entry)
101 unsigned long size;
102 mmfile_t src, dst;
103 xpparam_t xpp;
104 xdemitconf_t xecfg;
105 xdemitcb_t ecb;
107 xpp.flags = 0;
108 memset(&xecfg, 0, sizeof(xecfg));
109 xecfg.ctxlen = 3;
110 ecb.outf = show_outf;
111 ecb.priv = NULL;
113 src.ptr = origin(entry, &size);
114 if (!src.ptr)
115 size = 0;
116 src.size = size;
117 dst.ptr = result(entry, &size);
118 if (!dst.ptr)
119 size = 0;
120 dst.size = size;
121 xdi_diff(&src, &dst, &xpp, &xecfg, &ecb);
122 free(src.ptr);
123 free(dst.ptr);
126 static void show_result_list(struct merge_list *entry)
128 printf("%s\n", explanation(entry));
129 do {
130 struct merge_list *link = entry->link;
131 static const char *desc[4] = { "result", "base", "our", "their" };
132 printf(" %-6s %o %s %s\n", desc[entry->stage], entry->mode, sha1_to_hex(entry->blob->object.sha1), entry->path);
133 entry = link;
134 } while (entry);
137 static void show_result(void)
139 struct merge_list *walk;
141 walk = merge_result;
142 while (walk) {
143 show_result_list(walk);
144 show_diff(walk);
145 walk = walk->next;
149 /* An empty entry never compares same, not even to another empty entry */
150 static int same_entry(struct name_entry *a, struct name_entry *b)
152 return a->sha1 &&
153 b->sha1 &&
154 !hashcmp(a->sha1, b->sha1) &&
155 a->mode == b->mode;
158 static int both_empty(struct name_entry *a, struct name_entry *b)
160 return !(a->sha1 || b->sha1);
163 static struct merge_list *create_entry(unsigned stage, unsigned mode, const unsigned char *sha1, const char *path)
165 struct merge_list *res = xcalloc(1, sizeof(*res));
167 res->stage = stage;
168 res->path = path;
169 res->mode = mode;
170 res->blob = lookup_blob(sha1);
171 return res;
174 static char *traverse_path(const struct traverse_info *info, const struct name_entry *n)
176 char *path = xmalloc(traverse_path_len(info, n) + 1);
177 return make_traverse_path(path, info, n);
180 static void resolve(const struct traverse_info *info, struct name_entry *ours, struct name_entry *result)
182 struct merge_list *orig, *final;
183 const char *path;
185 /* If it's already ours, don't bother showing it */
186 if (!ours)
187 return;
189 path = traverse_path(info, result);
190 orig = create_entry(2, ours->mode, ours->sha1, path);
191 final = create_entry(0, result->mode, result->sha1, path);
193 final->link = orig;
195 add_merge_entry(final);
198 static void unresolved_directory(const struct traverse_info *info, struct name_entry n[3],
199 int df_conflict)
201 char *newbase;
202 struct name_entry *p;
203 struct tree_desc t[3];
204 void *buf0, *buf1, *buf2;
206 for (p = n; p < n + 3; p++) {
207 if (p->mode && S_ISDIR(p->mode))
208 break;
210 if (n + 3 <= p)
211 return; /* there is no tree here */
213 newbase = traverse_path(info, p);
215 #define ENTRY_SHA1(e) (((e)->mode && S_ISDIR((e)->mode)) ? (e)->sha1 : NULL)
216 buf0 = fill_tree_descriptor(t+0, ENTRY_SHA1(n + 0));
217 buf1 = fill_tree_descriptor(t+1, ENTRY_SHA1(n + 1));
218 buf2 = fill_tree_descriptor(t+2, ENTRY_SHA1(n + 2));
219 #undef ENTRY_SHA1
221 merge_trees_recursive(t, newbase, df_conflict);
223 free(buf0);
224 free(buf1);
225 free(buf2);
226 free(newbase);
230 static struct merge_list *link_entry(unsigned stage, const struct traverse_info *info, struct name_entry *n, struct merge_list *entry)
232 const char *path;
233 struct merge_list *link;
235 if (!n->mode)
236 return entry;
237 if (entry)
238 path = entry->path;
239 else
240 path = traverse_path(info, n);
241 link = create_entry(stage, n->mode, n->sha1, path);
242 link->link = entry;
243 return link;
246 static void unresolved(const struct traverse_info *info, struct name_entry n[3])
248 struct merge_list *entry = NULL;
249 int i;
250 unsigned dirmask = 0, mask = 0;
252 for (i = 0; i < 3; i++) {
253 mask |= (1 << i);
255 * Treat missing entries as directories so that we return
256 * after unresolved_directory has handled this.
258 if (!n[i].mode || S_ISDIR(n[i].mode))
259 dirmask |= (1 << i);
262 unresolved_directory(info, n, dirmask && (dirmask != mask));
264 if (dirmask == mask)
265 return;
267 if (n[2].mode && !S_ISDIR(n[2].mode))
268 entry = link_entry(3, info, n + 2, entry);
269 if (n[1].mode && !S_ISDIR(n[1].mode))
270 entry = link_entry(2, info, n + 1, entry);
271 if (n[0].mode && !S_ISDIR(n[0].mode))
272 entry = link_entry(1, info, n + 0, entry);
274 add_merge_entry(entry);
278 * Merge two trees together (t[1] and t[2]), using a common base (t[0])
279 * as the origin.
281 * This walks the (sorted) trees in lock-step, checking every possible
282 * name. Note that directories automatically sort differently from other
283 * files (see "base_name_compare"), so you'll never see file/directory
284 * conflicts, because they won't ever compare the same.
286 * IOW, if a directory changes to a filename, it will automatically be
287 * seen as the directory going away, and the filename being created.
289 * Think of this as a three-way diff.
291 * The output will be either:
292 * - successful merge
293 * "0 mode sha1 filename"
294 * NOTE NOTE NOTE! FIXME! We really really need to walk the index
295 * in parallel with this too!
297 * - conflict:
298 * "1 mode sha1 filename"
299 * "2 mode sha1 filename"
300 * "3 mode sha1 filename"
301 * where not all of the 1/2/3 lines may exist, of course.
303 * The successful merge rules are the same as for the three-way merge
304 * in git-read-tree.
306 static int threeway_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *entry, struct traverse_info *info)
308 /* Same in both? */
309 if (same_entry(entry+1, entry+2) || both_empty(entry+1, entry+2)) {
310 /* Modified, added or removed identically */
311 resolve(info, NULL, entry+1);
312 return mask;
315 if (same_entry(entry+0, entry+1)) {
316 if (entry[2].sha1 && !S_ISDIR(entry[2].mode)) {
317 /* We did not touch, they modified -- take theirs */
318 resolve(info, entry+1, entry+2);
319 return mask;
322 * If we did not touch a directory but they made it
323 * into a file, we fall through and unresolved()
324 * recurses down. Likewise for the opposite case.
328 if (same_entry(entry+0, entry+2) || both_empty(entry+0, entry+2)) {
329 /* We added, modified or removed, they did not touch -- take ours */
330 resolve(info, NULL, entry+1);
331 return mask;
334 unresolved(info, entry);
335 return mask;
338 static void merge_trees_recursive(struct tree_desc t[3], const char *base, int df_conflict)
340 struct traverse_info info;
342 setup_traverse_info(&info, base);
343 info.data = &df_conflict;
344 info.fn = threeway_callback;
345 traverse_trees(3, t, &info);
348 static void merge_trees(struct tree_desc t[3], const char *base)
350 merge_trees_recursive(t, base, 0);
353 static void *get_tree_descriptor(struct tree_desc *desc, const char *rev)
355 unsigned char sha1[20];
356 void *buf;
358 if (get_sha1(rev, sha1))
359 die("unknown rev %s", rev);
360 buf = fill_tree_descriptor(desc, sha1);
361 if (!buf)
362 die("%s is not a tree", rev);
363 return buf;
366 int cmd_merge_tree(int argc, const char **argv, const char *prefix)
368 struct tree_desc t[3];
369 void *buf1, *buf2, *buf3;
371 if (argc != 4)
372 usage(merge_tree_usage);
374 buf1 = get_tree_descriptor(t+0, argv[1]);
375 buf2 = get_tree_descriptor(t+1, argv[2]);
376 buf3 = get_tree_descriptor(t+2, argv[3]);
377 merge_trees(t, "");
378 free(buf1);
379 free(buf2);
380 free(buf3);
382 show_result();
383 return 0;