tree-walk: add a strbuf wrapper for make_traverse_path()
[git/git.git] / builtin / merge-tree.c
CommitLineData
f8adbec9 1#define USE_THE_INDEX_COMPATIBILITY_MACROS
c2e86add 2#include "builtin.h"
1b0c7174 3#include "tree-walk.h"
0c799383 4#include "xdiff-interface.h"
cbd53a21 5#include "object-store.h"
da14a7ff 6#include "repository.h"
83788070 7#include "blob.h"
d807c4a0 8#include "exec-cmd.h"
fa2364ec 9#include "merge-blobs.h"
492e0759 10
34263de0 11static const char merge_tree_usage[] = "git merge-tree <base-tree> <branch1> <branch2>";
492e0759 12
83788070
LT
13struct merge_list {
14 struct merge_list *next;
15 struct merge_list *link; /* other stages for this object */
16
b13112fa 17 unsigned int stage : 2;
83788070
LT
18 unsigned int mode;
19 const char *path;
20 struct blob *blob;
21};
22
23static struct merge_list *merge_result, **merge_result_end = &merge_result;
24
25static void add_merge_entry(struct merge_list *entry)
26{
27 *merge_result_end = entry;
28 merge_result_end = &entry->next;
29}
30
57065289 31static void merge_trees(struct tree_desc t[3], const char *base);
492e0759 32
83788070
LT
33static 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
0c799383
LT
59static void *result(struct merge_list *entry, unsigned long *size)
60{
21666f1a 61 enum object_type type;
0c799383 62 struct blob *base, *our, *their;
21baa6e0 63 const char *path = entry->path;
0c799383
LT
64
65 if (!entry->stage)
b4f5aca4 66 return read_object_file(&entry->blob->object.oid, &type, size);
0c799383
LT
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;
f8adbec9
NTND
80 return merge_blobs(the_repository->index, path,
81 base, our, their, size);
0c799383
LT
82}
83
84static void *origin(struct merge_list *entry, unsigned long *size)
85{
21666f1a 86 enum object_type type;
0c799383
LT
87 while (entry) {
88 if (entry->stage == 2)
b4f5aca4 89 return read_object_file(&entry->blob->object.oid,
90 &type, size);
0c799383
LT
91 entry = entry->link;
92 }
93 return NULL;
94}
95
96static 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
104static 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
582aa00b 112 xpp.flags = 0;
30b25010 113 memset(&xecfg, 0, sizeof(xecfg));
0c799383 114 xecfg.ctxlen = 3;
611e42a5
JK
115 ecb.out_hunk = NULL;
116 ecb.out_line = show_outf;
0c799383
LT
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;
3efb9880
JK
127 if (xdi_diff(&src, &dst, &xpp, &xecfg, &ecb))
128 die("unable to generate diff");
0c799383
LT
129 free(src.ptr);
130 free(dst.ptr);
131}
132
83788070
LT
133static 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" };
f2fd0760 139 printf(" %-6s %o %s %s\n", desc[entry->stage], entry->mode, oid_to_hex(&entry->blob->object.oid), entry->path);
83788070
LT
140 entry = link;
141 } while (entry);
142}
143
144static void show_result(void)
145{
146 struct merge_list *walk;
147
148 walk = merge_result;
149 while (walk) {
150 show_result_list(walk);
0c799383 151 show_diff(walk);
83788070
LT
152 walk = walk->next;
153 }
154}
155
492e0759
LT
156/* An empty entry never compares same, not even to another empty entry */
157static int same_entry(struct name_entry *a, struct name_entry *b)
158{
ea82b2a0 159 return !is_null_oid(&a->oid) &&
160 !is_null_oid(&b->oid) &&
161 oideq(&a->oid, &b->oid) &&
492e0759
LT
162 a->mode == b->mode;
163}
164
aacecc3b
JK
165static int both_empty(struct name_entry *a, struct name_entry *b)
166{
ea82b2a0 167 return is_null_oid(&a->oid) && is_null_oid(&b->oid);
aacecc3b
JK
168}
169
3e930981 170static struct merge_list *create_entry(unsigned stage, unsigned mode, const struct object_id *oid, const char *path)
492e0759 171{
19d4b416 172 struct merge_list *res = xcalloc(1, sizeof(*res));
83788070 173
83788070
LT
174 res->stage = stage;
175 res->path = path;
176 res->mode = mode;
da14a7ff 177 res->blob = lookup_blob(the_repository, oid);
83788070 178 return res;
01df5297
LT
179}
180
40d934df
LT
181static char *traverse_path(const struct traverse_info *info, const struct name_entry *n)
182{
c43ab062
JK
183 struct strbuf buf = STRBUF_INIT;
184 strbuf_make_traverse_path(&buf, info, n->path, n->pathlen);
185 return strbuf_detach(&buf, NULL);
40d934df
LT
186}
187
8dd15c6a 188static void resolve(const struct traverse_info *info, struct name_entry *ours, struct name_entry *result)
01df5297 189{
83788070
LT
190 struct merge_list *orig, *final;
191 const char *path;
192
8dd15c6a
JH
193 /* If it's already ours, don't bother showing it */
194 if (!ours)
01df5297 195 return;
01df5297 196
40d934df 197 path = traverse_path(info, result);
ea82b2a0 198 orig = create_entry(2, ours->mode, &ours->oid, path);
199 final = create_entry(0, result->mode, &result->oid, path);
83788070
LT
200
201 final->link = orig;
202
203 add_merge_entry(final);
492e0759
LT
204}
205
57065289
RS
206static void unresolved_directory(const struct traverse_info *info,
207 struct name_entry n[3])
492e0759 208{
492e0759
LT
209 char *newbase;
210 struct name_entry *p;
211 struct tree_desc t[3];
212 void *buf0, *buf1, *buf2;
213
35ffe758
JH
214 for (p = n; p < n + 3; p++) {
215 if (p->mode && S_ISDIR(p->mode))
216 break;
492e0759 217 }
35ffe758
JH
218 if (n + 3 <= p)
219 return; /* there is no tree here */
8dd15c6a 220
40d934df 221 newbase = traverse_path(info, p);
35ffe758 222
ea82b2a0 223#define ENTRY_OID(e) (((e)->mode && S_ISDIR((e)->mode)) ? &(e)->oid : NULL)
5c377d3d
RS
224 buf0 = fill_tree_descriptor(t + 0, ENTRY_OID(n + 0));
225 buf1 = fill_tree_descriptor(t + 1, ENTRY_OID(n + 1));
226 buf2 = fill_tree_descriptor(t + 2, ENTRY_OID(n + 2));
227#undef ENTRY_OID
35ffe758 228
57065289 229 merge_trees(t, newbase);
492e0759
LT
230
231 free(buf0);
232 free(buf1);
233 free(buf2);
234 free(newbase);
492e0759
LT
235}
236
83788070 237
40d934df 238static struct merge_list *link_entry(unsigned stage, const struct traverse_info *info, struct name_entry *n, struct merge_list *entry)
83788070
LT
239{
240 const char *path;
241 struct merge_list *link;
242
243 if (!n->mode)
244 return entry;
245 if (entry)
246 path = entry->path;
247 else
40d934df 248 path = traverse_path(info, n);
ea82b2a0 249 link = create_entry(stage, n->mode, &n->oid, path);
83788070
LT
250 link->link = entry;
251 return link;
252}
253
40d934df 254static void unresolved(const struct traverse_info *info, struct name_entry n[3])
492e0759 255{
83788070 256 struct merge_list *entry = NULL;
35ffe758
JH
257 int i;
258 unsigned dirmask = 0, mask = 0;
259
260 for (i = 0; i < 3; i++) {
187c00c6 261 mask |= (1 << i);
94883b43
JK
262 /*
263 * Treat missing entries as directories so that we return
264 * after unresolved_directory has handled this.
265 */
266 if (!n[i].mode || S_ISDIR(n[i].mode))
35ffe758
JH
267 dirmask |= (1 << i);
268 }
269
57065289 270 unresolved_directory(info, n);
83788070 271
35ffe758 272 if (dirmask == mask)
492e0759 273 return;
83788070 274
35ffe758
JH
275 if (n[2].mode && !S_ISDIR(n[2].mode))
276 entry = link_entry(3, info, n + 2, entry);
277 if (n[1].mode && !S_ISDIR(n[1].mode))
278 entry = link_entry(2, info, n + 1, entry);
279 if (n[0].mode && !S_ISDIR(n[0].mode))
280 entry = link_entry(1, info, n + 0, entry);
83788070
LT
281
282 add_merge_entry(entry);
492e0759
LT
283}
284
164dcb97
LT
285/*
286 * Merge two trees together (t[1] and t[2]), using a common base (t[0])
287 * as the origin.
288 *
289 * This walks the (sorted) trees in lock-step, checking every possible
290 * name. Note that directories automatically sort differently from other
291 * files (see "base_name_compare"), so you'll never see file/directory
292 * conflicts, because they won't ever compare the same.
293 *
294 * IOW, if a directory changes to a filename, it will automatically be
295 * seen as the directory going away, and the filename being created.
296 *
297 * Think of this as a three-way diff.
298 *
299 * The output will be either:
300 * - successful merge
301 * "0 mode sha1 filename"
302 * NOTE NOTE NOTE! FIXME! We really really need to walk the index
303 * in parallel with this too!
304 *
305 * - conflict:
306 * "1 mode sha1 filename"
307 * "2 mode sha1 filename"
308 * "3 mode sha1 filename"
309 * where not all of the 1/2/3 lines may exist, of course.
310 *
311 * The successful merge rules are the same as for the three-way merge
312 * in git-read-tree.
313 */
91e4f036 314static int threeway_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *entry, struct traverse_info *info)
164dcb97
LT
315{
316 /* Same in both? */
ab5f4242 317 if (same_entry(entry+1, entry+2) || both_empty(entry+1, entry+2)) {
aacecc3b
JK
318 /* Modified, added or removed identically */
319 resolve(info, NULL, entry+1);
320 return mask;
164dcb97 321 }
492e0759 322
164dcb97 323 if (same_entry(entry+0, entry+1)) {
ea82b2a0 324 if (!is_null_oid(&entry[2].oid) && !S_ISDIR(entry[2].mode)) {
8dd15c6a 325 /* We did not touch, they modified -- take theirs */
40d934df 326 resolve(info, entry+1, entry+2);
5803c6f8 327 return mask;
492e0759 328 }
8dd15c6a
JH
329 /*
330 * If we did not touch a directory but they made it
331 * into a file, we fall through and unresolved()
332 * recurses down. Likewise for the opposite case.
333 */
164dcb97 334 }
492e0759 335
aacecc3b
JK
336 if (same_entry(entry+0, entry+2) || both_empty(entry+0, entry+2)) {
337 /* We added, modified or removed, they did not touch -- take ours */
338 resolve(info, NULL, entry+1);
339 return mask;
492e0759 340 }
164dcb97 341
40d934df 342 unresolved(info, entry);
5803c6f8 343 return mask;
164dcb97
LT
344}
345
57065289 346static void merge_trees(struct tree_desc t[3], const char *base)
164dcb97 347{
40d934df
LT
348 struct traverse_info info;
349
350 setup_traverse_info(&info, base);
351 info.fn = threeway_callback;
67022e02 352 traverse_trees(&the_index, 3, t, &info);
492e0759
LT
353}
354
355static void *get_tree_descriptor(struct tree_desc *desc, const char *rev)
356{
d1a35e5c 357 struct object_id oid;
492e0759
LT
358 void *buf;
359
d1a35e5c 360 if (get_oid(rev, &oid))
492e0759 361 die("unknown rev %s", rev);
5c377d3d 362 buf = fill_tree_descriptor(desc, &oid);
492e0759
LT
363 if (!buf)
364 die("%s is not a tree", rev);
365 return buf;
366}
367
907a7cb5 368int cmd_merge_tree(int argc, const char **argv, const char *prefix)
492e0759
LT
369{
370 struct tree_desc t[3];
371 void *buf1, *buf2, *buf3;
372
5b6df8e4 373 if (argc != 4)
492e0759
LT
374 usage(merge_tree_usage);
375
376 buf1 = get_tree_descriptor(t+0, argv[1]);
377 buf2 = get_tree_descriptor(t+1, argv[2]);
378 buf3 = get_tree_descriptor(t+2, argv[3]);
379 merge_trees(t, "");
380 free(buf1);
381 free(buf2);
382 free(buf3);
83788070
LT
383
384 show_result();
492e0759
LT
385 return 0;
386}