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Commit | Line | Data |
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5e3f94df | 1 | #include "git-compat-util.h" |
41771fa4 | 2 | #include "hex.h" |
d4ff2072 | 3 | #include "match-trees.h" |
a034e910 | 4 | #include "strbuf.h" |
68faf689 JH |
5 | #include "tree.h" |
6 | #include "tree-walk.h" | |
a034e910 | 7 | #include "object-store-ll.h" |
68faf689 | 8 | |
667f71c3 | 9 | static int score_missing(unsigned mode) |
68faf689 JH |
10 | { |
11 | int score; | |
12 | ||
13 | if (S_ISDIR(mode)) | |
14 | score = -1000; | |
15 | else if (S_ISLNK(mode)) | |
16 | score = -500; | |
17 | else | |
18 | score = -50; | |
19 | return score; | |
20 | } | |
21 | ||
667f71c3 | 22 | static int score_differs(unsigned mode1, unsigned mode2) |
68faf689 JH |
23 | { |
24 | int score; | |
25 | ||
26 | if (S_ISDIR(mode1) != S_ISDIR(mode2)) | |
27 | score = -100; | |
28 | else if (S_ISLNK(mode1) != S_ISLNK(mode2)) | |
29 | score = -50; | |
30 | else | |
31 | score = -5; | |
32 | return score; | |
33 | } | |
34 | ||
667f71c3 | 35 | static int score_matches(unsigned mode1, unsigned mode2) |
68faf689 JH |
36 | { |
37 | int score; | |
38 | ||
39 | /* Heh, we found SHA-1 collisions between different kind of objects */ | |
40 | if (S_ISDIR(mode1) != S_ISDIR(mode2)) | |
41 | score = -100; | |
42 | else if (S_ISLNK(mode1) != S_ISLNK(mode2)) | |
43 | score = -50; | |
44 | ||
45 | else if (S_ISDIR(mode1)) | |
46 | score = 1000; | |
47 | else if (S_ISLNK(mode1)) | |
48 | score = 500; | |
49 | else | |
50 | score = 250; | |
51 | return score; | |
52 | } | |
53 | ||
10a3fb00 | 54 | static void *fill_tree_desc_strict(struct tree_desc *desc, |
b6aec868 | 55 | const struct object_id *hash) |
10a3fb00 RS |
56 | { |
57 | void *buffer; | |
58 | enum object_type type; | |
59 | unsigned long size; | |
60 | ||
bc726bd0 | 61 | buffer = repo_read_object_file(the_repository, hash, &type, &size); |
10a3fb00 | 62 | if (!buffer) |
b6aec868 | 63 | die("unable to read tree (%s)", oid_to_hex(hash)); |
10a3fb00 | 64 | if (type != OBJ_TREE) |
b6aec868 | 65 | die("%s is not a tree", oid_to_hex(hash)); |
10a3fb00 RS |
66 | init_tree_desc(desc, buffer, size); |
67 | return buffer; | |
68 | } | |
69 | ||
d8febde3 RS |
70 | static int base_name_entries_compare(const struct name_entry *a, |
71 | const struct name_entry *b) | |
72 | { | |
73 | return base_name_compare(a->path, tree_entry_len(a), a->mode, | |
74 | b->path, tree_entry_len(b), b->mode); | |
75 | } | |
76 | ||
68faf689 JH |
77 | /* |
78 | * Inspect two trees, and give a score that tells how similar they are. | |
79 | */ | |
b6aec868 | 80 | static int score_trees(const struct object_id *hash1, const struct object_id *hash2) |
68faf689 JH |
81 | { |
82 | struct tree_desc one; | |
83 | struct tree_desc two; | |
10a3fb00 RS |
84 | void *one_buf = fill_tree_desc_strict(&one, hash1); |
85 | void *two_buf = fill_tree_desc_strict(&two, hash2); | |
68faf689 | 86 | int score = 0; |
68faf689 | 87 | |
d8febde3 | 88 | for (;;) { |
68faf689 JH |
89 | int cmp; |
90 | ||
2ec41507 JK |
91 | if (one.size && two.size) |
92 | cmp = base_name_entries_compare(&one.entry, &two.entry); | |
93 | else if (one.size) | |
68faf689 | 94 | /* two lacks this entry */ |
d8febde3 | 95 | cmp = -1; |
2ec41507 | 96 | else if (two.size) |
d8febde3 RS |
97 | /* two has more entries */ |
98 | cmp = 1; | |
99 | else | |
100 | break; | |
101 | ||
2ec41507 | 102 | if (cmp < 0) { |
68faf689 | 103 | /* path1 does not appear in two */ |
667f71c3 | 104 | score += score_missing(one.entry.mode); |
2ec41507 JK |
105 | update_tree_entry(&one); |
106 | } else if (cmp > 0) { | |
68faf689 | 107 | /* path2 does not appear in one */ |
667f71c3 | 108 | score += score_missing(two.entry.mode); |
2ec41507 JK |
109 | update_tree_entry(&two); |
110 | } else { | |
111 | /* path appears in both */ | |
ea82b2a0 | 112 | if (!oideq(&one.entry.oid, &two.entry.oid)) { |
2ec41507 JK |
113 | /* they are different */ |
114 | score += score_differs(one.entry.mode, | |
667f71c3 | 115 | two.entry.mode); |
2ec41507 JK |
116 | } else { |
117 | /* same subtree or blob */ | |
118 | score += score_matches(one.entry.mode, | |
667f71c3 | 119 | two.entry.mode); |
2ec41507 JK |
120 | } |
121 | update_tree_entry(&one); | |
122 | update_tree_entry(&two); | |
123 | } | |
68faf689 JH |
124 | } |
125 | free(one_buf); | |
126 | free(two_buf); | |
127 | return score; | |
128 | } | |
129 | ||
130 | /* | |
131 | * Match one itself and its subtrees with two and pick the best match. | |
132 | */ | |
b6aec868 | 133 | static void match_trees(const struct object_id *hash1, |
134 | const struct object_id *hash2, | |
68faf689 JH |
135 | int *best_score, |
136 | char **best_match, | |
538dfe73 | 137 | const char *base, |
68faf689 JH |
138 | int recurse_limit) |
139 | { | |
140 | struct tree_desc one; | |
10a3fb00 | 141 | void *one_buf = fill_tree_desc_strict(&one, hash1); |
68faf689 JH |
142 | |
143 | while (one.size) { | |
144 | const char *path; | |
ce6663a9 | 145 | const struct object_id *elem; |
5ec1e728 | 146 | unsigned short mode; |
68faf689 JH |
147 | int score; |
148 | ||
149 | elem = tree_entry_extract(&one, &path, &mode); | |
150 | if (!S_ISDIR(mode)) | |
151 | goto next; | |
b6aec868 | 152 | score = score_trees(elem, hash2); |
68faf689 | 153 | if (*best_score < score) { |
68faf689 | 154 | free(*best_match); |
28310186 | 155 | *best_match = xstrfmt("%s%s", base, path); |
68faf689 JH |
156 | *best_score = score; |
157 | } | |
158 | if (recurse_limit) { | |
28310186 | 159 | char *newbase = xstrfmt("%s%s/", base, path); |
b6aec868 | 160 | match_trees(elem, hash2, best_score, best_match, |
68faf689 JH |
161 | newbase, recurse_limit - 1); |
162 | free(newbase); | |
163 | } | |
164 | ||
165 | next: | |
166 | update_tree_entry(&one); | |
167 | } | |
168 | free(one_buf); | |
169 | } | |
170 | ||
171 | /* | |
3b34934d PO |
172 | * A tree "oid1" has a subdirectory at "prefix". Come up with a tree object by |
173 | * replacing it with another tree "oid2". | |
68faf689 | 174 | */ |
3b34934d PO |
175 | static int splice_tree(const struct object_id *oid1, const char *prefix, |
176 | const struct object_id *oid2, struct object_id *result) | |
68faf689 JH |
177 | { |
178 | char *subpath; | |
179 | int toplen; | |
180 | char *buf; | |
181 | unsigned long sz; | |
182 | struct tree_desc desc; | |
f55ac431 | 183 | unsigned char *rewrite_here; |
3b34934d PO |
184 | const struct object_id *rewrite_with; |
185 | struct object_id subtree; | |
68faf689 JH |
186 | enum object_type type; |
187 | int status; | |
188 | ||
2c5495f7 RM |
189 | subpath = strchrnul(prefix, '/'); |
190 | toplen = subpath - prefix; | |
191 | if (*subpath) | |
68faf689 | 192 | subpath++; |
68faf689 | 193 | |
bc726bd0 | 194 | buf = repo_read_object_file(the_repository, oid1, &type, &sz); |
68faf689 | 195 | if (!buf) |
3b34934d | 196 | die("cannot read tree %s", oid_to_hex(oid1)); |
68faf689 JH |
197 | init_tree_desc(&desc, buf, sz); |
198 | ||
199 | rewrite_here = NULL; | |
200 | while (desc.size) { | |
201 | const char *name; | |
5ec1e728 | 202 | unsigned short mode; |
68faf689 | 203 | |
36775ab5 | 204 | tree_entry_extract(&desc, &name, &mode); |
68faf689 JH |
205 | if (strlen(name) == toplen && |
206 | !memcmp(name, prefix, toplen)) { | |
207 | if (!S_ISDIR(mode)) | |
3b34934d PO |
208 | die("entry %s in tree %s is not a tree", name, |
209 | oid_to_hex(oid1)); | |
f55ac431 | 210 | |
211 | /* | |
212 | * We cast here for two reasons: | |
213 | * | |
214 | * - to flip the "char *" (for the path) to "unsigned | |
215 | * char *" (for the hash stored after it) | |
216 | * | |
217 | * - to discard the "const"; this is OK because we | |
218 | * know it points into our non-const "buf" | |
219 | */ | |
220 | rewrite_here = (unsigned char *)(desc.entry.path + | |
221 | strlen(desc.entry.path) + | |
222 | 1); | |
68faf689 JH |
223 | break; |
224 | } | |
225 | update_tree_entry(&desc); | |
226 | } | |
227 | if (!rewrite_here) | |
3b34934d PO |
228 | die("entry %.*s not found in tree %s", toplen, prefix, |
229 | oid_to_hex(oid1)); | |
2c5495f7 | 230 | if (*subpath) { |
f55ac431 | 231 | struct object_id tree_oid; |
92e2cab9 | 232 | oidread(&tree_oid, rewrite_here); |
f55ac431 | 233 | status = splice_tree(&tree_oid, subpath, oid2, &subtree); |
68faf689 JH |
234 | if (status) |
235 | return status; | |
3b34934d PO |
236 | rewrite_with = &subtree; |
237 | } else { | |
238 | rewrite_with = oid2; | |
68faf689 | 239 | } |
f55ac431 | 240 | hashcpy(rewrite_here, rewrite_with->hash); |
c80d226a | 241 | status = write_object_file(buf, sz, OBJ_TREE, result); |
68faf689 JH |
242 | free(buf); |
243 | return status; | |
244 | } | |
245 | ||
246 | /* | |
247 | * We are trying to come up with a merge between one and two that | |
248 | * results in a tree shape similar to one. The tree two might | |
249 | * correspond to a subtree of one, in which case it needs to be | |
250 | * shifted down by prefixing otherwise empty directories. On the | |
251 | * other hand, it could cover tree one and we might need to pick a | |
252 | * subtree of it. | |
253 | */ | |
90d34051 NTND |
254 | void shift_tree(struct repository *r, |
255 | const struct object_id *hash1, | |
82db3d44 | 256 | const struct object_id *hash2, |
257 | struct object_id *shifted, | |
68faf689 JH |
258 | int depth_limit) |
259 | { | |
260 | char *add_prefix; | |
261 | char *del_prefix; | |
262 | int add_score, del_score; | |
263 | ||
85e51b78 JH |
264 | /* |
265 | * NEEDSWORK: this limits the recursion depth to hardcoded | |
266 | * value '2' to avoid excessive overhead. | |
267 | */ | |
268 | if (!depth_limit) | |
269 | depth_limit = 2; | |
270 | ||
b6aec868 | 271 | add_score = del_score = score_trees(hash1, hash2); |
68faf689 JH |
272 | add_prefix = xcalloc(1, 1); |
273 | del_prefix = xcalloc(1, 1); | |
274 | ||
275 | /* | |
276 | * See if one's subtree resembles two; if so we need to prefix | |
277 | * two with a few fake trees to match the prefix. | |
278 | */ | |
b6aec868 | 279 | match_trees(hash1, hash2, &add_score, &add_prefix, "", depth_limit); |
68faf689 JH |
280 | |
281 | /* | |
282 | * See if two's subtree resembles one; if so we need to | |
283 | * pick only subtree of two. | |
284 | */ | |
b6aec868 | 285 | match_trees(hash2, hash1, &del_score, &del_prefix, "", depth_limit); |
68faf689 JH |
286 | |
287 | /* Assume we do not have to do any shifting */ | |
82db3d44 | 288 | oidcpy(shifted, hash2); |
68faf689 JH |
289 | |
290 | if (add_score < del_score) { | |
291 | /* We need to pick a subtree of two */ | |
5ec1e728 | 292 | unsigned short mode; |
68faf689 JH |
293 | |
294 | if (!*del_prefix) | |
295 | return; | |
296 | ||
90d34051 | 297 | if (get_tree_entry(r, hash2, del_prefix, shifted, &mode)) |
68faf689 | 298 | die("cannot find path %s in tree %s", |
82db3d44 | 299 | del_prefix, oid_to_hex(hash2)); |
68faf689 JH |
300 | return; |
301 | } | |
302 | ||
303 | if (!*add_prefix) | |
304 | return; | |
305 | ||
3b34934d | 306 | splice_tree(hash1, add_prefix, hash2, shifted); |
68faf689 | 307 | } |
85e51b78 JH |
308 | |
309 | /* | |
310 | * The user says the trees will be shifted by this much. | |
311 | * Unfortunately we cannot fundamentally tell which one to | |
312 | * be prefixed, as recursive merge can work in either direction. | |
313 | */ | |
90d34051 NTND |
314 | void shift_tree_by(struct repository *r, |
315 | const struct object_id *hash1, | |
82db3d44 | 316 | const struct object_id *hash2, |
317 | struct object_id *shifted, | |
85e51b78 JH |
318 | const char *shift_prefix) |
319 | { | |
82db3d44 | 320 | struct object_id sub1, sub2; |
5ec1e728 | 321 | unsigned short mode1, mode2; |
85e51b78 JH |
322 | unsigned candidate = 0; |
323 | ||
324 | /* Can hash2 be a tree at shift_prefix in tree hash1? */ | |
90d34051 | 325 | if (!get_tree_entry(r, hash1, shift_prefix, &sub1, &mode1) && |
85e51b78 JH |
326 | S_ISDIR(mode1)) |
327 | candidate |= 1; | |
328 | ||
329 | /* Can hash1 be a tree at shift_prefix in tree hash2? */ | |
90d34051 | 330 | if (!get_tree_entry(r, hash2, shift_prefix, &sub2, &mode2) && |
85e51b78 JH |
331 | S_ISDIR(mode2)) |
332 | candidate |= 2; | |
333 | ||
334 | if (candidate == 3) { | |
335 | /* Both are plausible -- we need to evaluate the score */ | |
b6aec868 | 336 | int best_score = score_trees(hash1, hash2); |
85e51b78 JH |
337 | int score; |
338 | ||
339 | candidate = 0; | |
b6aec868 | 340 | score = score_trees(&sub1, hash2); |
85e51b78 JH |
341 | if (score > best_score) { |
342 | candidate = 1; | |
343 | best_score = score; | |
344 | } | |
b6aec868 | 345 | score = score_trees(&sub2, hash1); |
85e51b78 JH |
346 | if (score > best_score) |
347 | candidate = 2; | |
348 | } | |
349 | ||
350 | if (!candidate) { | |
351 | /* Neither is plausible -- do not shift */ | |
82db3d44 | 352 | oidcpy(shifted, hash2); |
85e51b78 JH |
353 | return; |
354 | } | |
355 | ||
356 | if (candidate == 1) | |
357 | /* | |
358 | * shift tree2 down by adding shift_prefix above it | |
359 | * to match tree1. | |
360 | */ | |
3b34934d | 361 | splice_tree(hash1, shift_prefix, hash2, shifted); |
85e51b78 JH |
362 | else |
363 | /* | |
364 | * shift tree2 up by removing shift_prefix from it | |
365 | * to match tree1. | |
366 | */ | |
82db3d44 | 367 | oidcpy(shifted, &sub2); |
85e51b78 | 368 | } |