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