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1 | #define USE_THE_INDEX_COMPATIBILITY_MACROS | |
2 | #include "builtin.h" | |
3 | #include "tree-walk.h" | |
4 | #include "xdiff-interface.h" | |
5 | #include "object-store.h" | |
6 | #include "repository.h" | |
7 | #include "blob.h" | |
8 | #include "exec-cmd.h" | |
9 | #include "merge-blobs.h" | |
10 | ||
11 | static const char merge_tree_usage[] = "git merge-tree <base-tree> <branch1> <branch2>"; | |
12 | ||
13 | struct merge_list { | |
14 | struct merge_list *next; | |
15 | struct merge_list *link; /* other stages for this object */ | |
16 | ||
17 | unsigned int stage : 2; | |
18 | unsigned int mode; | |
19 | const char *path; | |
20 | struct blob *blob; | |
21 | }; | |
22 | ||
23 | static struct merge_list *merge_result, **merge_result_end = &merge_result; | |
24 | ||
25 | static void add_merge_entry(struct merge_list *entry) | |
26 | { | |
27 | *merge_result_end = entry; | |
28 | merge_result_end = &entry->next; | |
29 | } | |
30 | ||
31 | static void merge_trees(struct tree_desc t[3], const char *base); | |
32 | ||
33 | static const char *explanation(struct merge_list *entry) | |
34 | { | |
35 | switch (entry->stage) { | |
36 | case 0: | |
37 | return "merged"; | |
38 | case 3: | |
39 | return "added in remote"; | |
40 | case 2: | |
41 | if (entry->link) | |
42 | return "added in both"; | |
43 | return "added in local"; | |
44 | } | |
45 | ||
46 | /* Existed in base */ | |
47 | entry = entry->link; | |
48 | if (!entry) | |
49 | return "removed in both"; | |
50 | ||
51 | if (entry->link) | |
52 | return "changed in both"; | |
53 | ||
54 | if (entry->stage == 3) | |
55 | return "removed in local"; | |
56 | return "removed in remote"; | |
57 | } | |
58 | ||
59 | static void *result(struct merge_list *entry, unsigned long *size) | |
60 | { | |
61 | enum object_type type; | |
62 | struct blob *base, *our, *their; | |
63 | const char *path = entry->path; | |
64 | ||
65 | if (!entry->stage) | |
66 | return read_object_file(&entry->blob->object.oid, &type, size); | |
67 | base = NULL; | |
68 | if (entry->stage == 1) { | |
69 | base = entry->blob; | |
70 | entry = entry->link; | |
71 | } | |
72 | our = NULL; | |
73 | if (entry && entry->stage == 2) { | |
74 | our = entry->blob; | |
75 | entry = entry->link; | |
76 | } | |
77 | their = NULL; | |
78 | if (entry) | |
79 | their = entry->blob; | |
80 | return merge_blobs(the_repository->index, path, | |
81 | base, our, their, size); | |
82 | } | |
83 | ||
84 | static void *origin(struct merge_list *entry, unsigned long *size) | |
85 | { | |
86 | enum object_type type; | |
87 | while (entry) { | |
88 | if (entry->stage == 2) | |
89 | return read_object_file(&entry->blob->object.oid, | |
90 | &type, size); | |
91 | entry = entry->link; | |
92 | } | |
93 | return NULL; | |
94 | } | |
95 | ||
96 | static int show_outf(void *priv_, mmbuffer_t *mb, int nbuf) | |
97 | { | |
98 | int i; | |
99 | for (i = 0; i < nbuf; i++) | |
100 | printf("%.*s", (int) mb[i].size, mb[i].ptr); | |
101 | return 0; | |
102 | } | |
103 | ||
104 | static void show_diff(struct merge_list *entry) | |
105 | { | |
106 | unsigned long size; | |
107 | mmfile_t src, dst; | |
108 | xpparam_t xpp; | |
109 | xdemitconf_t xecfg; | |
110 | xdemitcb_t ecb; | |
111 | ||
112 | xpp.flags = 0; | |
113 | memset(&xecfg, 0, sizeof(xecfg)); | |
114 | xecfg.ctxlen = 3; | |
115 | ecb.out_hunk = NULL; | |
116 | ecb.out_line = show_outf; | |
117 | ecb.priv = NULL; | |
118 | ||
119 | src.ptr = origin(entry, &size); | |
120 | if (!src.ptr) | |
121 | size = 0; | |
122 | src.size = size; | |
123 | dst.ptr = result(entry, &size); | |
124 | if (!dst.ptr) | |
125 | size = 0; | |
126 | dst.size = size; | |
127 | if (xdi_diff(&src, &dst, &xpp, &xecfg, &ecb)) | |
128 | die("unable to generate diff"); | |
129 | free(src.ptr); | |
130 | free(dst.ptr); | |
131 | } | |
132 | ||
133 | static void show_result_list(struct merge_list *entry) | |
134 | { | |
135 | printf("%s\n", explanation(entry)); | |
136 | do { | |
137 | struct merge_list *link = entry->link; | |
138 | static const char *desc[4] = { "result", "base", "our", "their" }; | |
139 | printf(" %-6s %o %s %s\n", desc[entry->stage], entry->mode, oid_to_hex(&entry->blob->object.oid), entry->path); | |
140 | entry = link; | |
141 | } while (entry); | |
142 | } | |
143 | ||
144 | static void show_result(void) | |
145 | { | |
146 | struct merge_list *walk; | |
147 | ||
148 | walk = merge_result; | |
149 | while (walk) { | |
150 | show_result_list(walk); | |
151 | show_diff(walk); | |
152 | walk = walk->next; | |
153 | } | |
154 | } | |
155 | ||
156 | /* An empty entry never compares same, not even to another empty entry */ | |
157 | static int same_entry(struct name_entry *a, struct name_entry *b) | |
158 | { | |
159 | return !is_null_oid(&a->oid) && | |
160 | !is_null_oid(&b->oid) && | |
161 | oideq(&a->oid, &b->oid) && | |
162 | a->mode == b->mode; | |
163 | } | |
164 | ||
165 | static int both_empty(struct name_entry *a, struct name_entry *b) | |
166 | { | |
167 | return is_null_oid(&a->oid) && is_null_oid(&b->oid); | |
168 | } | |
169 | ||
170 | static struct merge_list *create_entry(unsigned stage, unsigned mode, const struct object_id *oid, const char *path) | |
171 | { | |
172 | struct merge_list *res = xcalloc(1, sizeof(*res)); | |
173 | ||
174 | res->stage = stage; | |
175 | res->path = path; | |
176 | res->mode = mode; | |
177 | res->blob = lookup_blob(the_repository, oid); | |
178 | return res; | |
179 | } | |
180 | ||
181 | static char *traverse_path(const struct traverse_info *info, const struct name_entry *n) | |
182 | { | |
183 | struct strbuf buf = STRBUF_INIT; | |
184 | strbuf_make_traverse_path(&buf, info, n->path, n->pathlen); | |
185 | return strbuf_detach(&buf, NULL); | |
186 | } | |
187 | ||
188 | static void resolve(const struct traverse_info *info, struct name_entry *ours, struct name_entry *result) | |
189 | { | |
190 | struct merge_list *orig, *final; | |
191 | const char *path; | |
192 | ||
193 | /* If it's already ours, don't bother showing it */ | |
194 | if (!ours) | |
195 | return; | |
196 | ||
197 | path = traverse_path(info, result); | |
198 | orig = create_entry(2, ours->mode, &ours->oid, path); | |
199 | final = create_entry(0, result->mode, &result->oid, path); | |
200 | ||
201 | final->link = orig; | |
202 | ||
203 | add_merge_entry(final); | |
204 | } | |
205 | ||
206 | static void unresolved_directory(const struct traverse_info *info, | |
207 | struct name_entry n[3]) | |
208 | { | |
209 | struct repository *r = the_repository; | |
210 | char *newbase; | |
211 | struct name_entry *p; | |
212 | struct tree_desc t[3]; | |
213 | void *buf0, *buf1, *buf2; | |
214 | ||
215 | for (p = n; p < n + 3; p++) { | |
216 | if (p->mode && S_ISDIR(p->mode)) | |
217 | break; | |
218 | } | |
219 | if (n + 3 <= p) | |
220 | return; /* there is no tree here */ | |
221 | ||
222 | newbase = traverse_path(info, p); | |
223 | ||
224 | #define ENTRY_OID(e) (((e)->mode && S_ISDIR((e)->mode)) ? &(e)->oid : NULL) | |
225 | buf0 = fill_tree_descriptor(r, t + 0, ENTRY_OID(n + 0)); | |
226 | buf1 = fill_tree_descriptor(r, t + 1, ENTRY_OID(n + 1)); | |
227 | buf2 = fill_tree_descriptor(r, t + 2, ENTRY_OID(n + 2)); | |
228 | #undef ENTRY_OID | |
229 | ||
230 | merge_trees(t, newbase); | |
231 | ||
232 | free(buf0); | |
233 | free(buf1); | |
234 | free(buf2); | |
235 | free(newbase); | |
236 | } | |
237 | ||
238 | ||
239 | static struct merge_list *link_entry(unsigned stage, const struct traverse_info *info, struct name_entry *n, struct merge_list *entry) | |
240 | { | |
241 | const char *path; | |
242 | struct merge_list *link; | |
243 | ||
244 | if (!n->mode) | |
245 | return entry; | |
246 | if (entry) | |
247 | path = entry->path; | |
248 | else | |
249 | path = traverse_path(info, n); | |
250 | link = create_entry(stage, n->mode, &n->oid, path); | |
251 | link->link = entry; | |
252 | return link; | |
253 | } | |
254 | ||
255 | static void unresolved(const struct traverse_info *info, struct name_entry n[3]) | |
256 | { | |
257 | struct merge_list *entry = NULL; | |
258 | int i; | |
259 | unsigned dirmask = 0, mask = 0; | |
260 | ||
261 | for (i = 0; i < 3; i++) { | |
262 | mask |= (1 << i); | |
263 | /* | |
264 | * Treat missing entries as directories so that we return | |
265 | * after unresolved_directory has handled this. | |
266 | */ | |
267 | if (!n[i].mode || S_ISDIR(n[i].mode)) | |
268 | dirmask |= (1 << i); | |
269 | } | |
270 | ||
271 | unresolved_directory(info, n); | |
272 | ||
273 | if (dirmask == mask) | |
274 | return; | |
275 | ||
276 | if (n[2].mode && !S_ISDIR(n[2].mode)) | |
277 | entry = link_entry(3, info, n + 2, entry); | |
278 | if (n[1].mode && !S_ISDIR(n[1].mode)) | |
279 | entry = link_entry(2, info, n + 1, entry); | |
280 | if (n[0].mode && !S_ISDIR(n[0].mode)) | |
281 | entry = link_entry(1, info, n + 0, entry); | |
282 | ||
283 | add_merge_entry(entry); | |
284 | } | |
285 | ||
286 | /* | |
287 | * Merge two trees together (t[1] and t[2]), using a common base (t[0]) | |
288 | * as the origin. | |
289 | * | |
290 | * This walks the (sorted) trees in lock-step, checking every possible | |
291 | * name. Note that directories automatically sort differently from other | |
292 | * files (see "base_name_compare"), so you'll never see file/directory | |
293 | * conflicts, because they won't ever compare the same. | |
294 | * | |
295 | * IOW, if a directory changes to a filename, it will automatically be | |
296 | * seen as the directory going away, and the filename being created. | |
297 | * | |
298 | * Think of this as a three-way diff. | |
299 | * | |
300 | * The output will be either: | |
301 | * - successful merge | |
302 | * "0 mode sha1 filename" | |
303 | * NOTE NOTE NOTE! FIXME! We really really need to walk the index | |
304 | * in parallel with this too! | |
305 | * | |
306 | * - conflict: | |
307 | * "1 mode sha1 filename" | |
308 | * "2 mode sha1 filename" | |
309 | * "3 mode sha1 filename" | |
310 | * where not all of the 1/2/3 lines may exist, of course. | |
311 | * | |
312 | * The successful merge rules are the same as for the three-way merge | |
313 | * in git-read-tree. | |
314 | */ | |
315 | static int threeway_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *entry, struct traverse_info *info) | |
316 | { | |
317 | /* Same in both? */ | |
318 | if (same_entry(entry+1, entry+2) || both_empty(entry+1, entry+2)) { | |
319 | /* Modified, added or removed identically */ | |
320 | resolve(info, NULL, entry+1); | |
321 | return mask; | |
322 | } | |
323 | ||
324 | if (same_entry(entry+0, entry+1)) { | |
325 | if (!is_null_oid(&entry[2].oid) && !S_ISDIR(entry[2].mode)) { | |
326 | /* We did not touch, they modified -- take theirs */ | |
327 | resolve(info, entry+1, entry+2); | |
328 | return mask; | |
329 | } | |
330 | /* | |
331 | * If we did not touch a directory but they made it | |
332 | * into a file, we fall through and unresolved() | |
333 | * recurses down. Likewise for the opposite case. | |
334 | */ | |
335 | } | |
336 | ||
337 | if (same_entry(entry+0, entry+2) || both_empty(entry+0, entry+2)) { | |
338 | /* We added, modified or removed, they did not touch -- take ours */ | |
339 | resolve(info, NULL, entry+1); | |
340 | return mask; | |
341 | } | |
342 | ||
343 | unresolved(info, entry); | |
344 | return mask; | |
345 | } | |
346 | ||
347 | static void merge_trees(struct tree_desc t[3], const char *base) | |
348 | { | |
349 | struct traverse_info info; | |
350 | ||
351 | setup_traverse_info(&info, base); | |
352 | info.fn = threeway_callback; | |
353 | traverse_trees(&the_index, 3, t, &info); | |
354 | } | |
355 | ||
356 | static void *get_tree_descriptor(struct repository *r, | |
357 | struct tree_desc *desc, | |
358 | const char *rev) | |
359 | { | |
360 | struct object_id oid; | |
361 | void *buf; | |
362 | ||
363 | if (repo_get_oid(r, rev, &oid)) | |
364 | die("unknown rev %s", rev); | |
365 | buf = fill_tree_descriptor(r, desc, &oid); | |
366 | if (!buf) | |
367 | die("%s is not a tree", rev); | |
368 | return buf; | |
369 | } | |
370 | ||
371 | int cmd_merge_tree(int argc, const char **argv, const char *prefix) | |
372 | { | |
373 | struct repository *r = the_repository; | |
374 | struct tree_desc t[3]; | |
375 | void *buf1, *buf2, *buf3; | |
376 | ||
377 | if (argc != 4) | |
378 | usage(merge_tree_usage); | |
379 | ||
380 | buf1 = get_tree_descriptor(r, t+0, argv[1]); | |
381 | buf2 = get_tree_descriptor(r, t+1, argv[2]); | |
382 | buf3 = get_tree_descriptor(r, t+2, argv[3]); | |
383 | merge_trees(t, ""); | |
384 | free(buf1); | |
385 | free(buf2); | |
386 | free(buf3); | |
387 | ||
388 | show_result(); | |
389 | return 0; | |
390 | } |