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1 | #include "cache.h" | |
2 | #include "string-list.h" | |
3 | #include "rerere.h" | |
4 | #include "xdiff/xdiff.h" | |
5 | #include "xdiff-interface.h" | |
6 | ||
7 | /* if rerere_enabled == -1, fall back to detection of .git/rr-cache */ | |
8 | static int rerere_enabled = -1; | |
9 | ||
10 | /* automatically update cleanly resolved paths to the index */ | |
11 | static int rerere_autoupdate; | |
12 | ||
13 | static char *merge_rr_path; | |
14 | ||
15 | static const char *rr_path(const char *name, const char *file) | |
16 | { | |
17 | return git_path("rr-cache/%s/%s", name, file); | |
18 | } | |
19 | ||
20 | static int has_resolution(const char *name) | |
21 | { | |
22 | struct stat st; | |
23 | return !stat(rr_path(name, "postimage"), &st); | |
24 | } | |
25 | ||
26 | static void read_rr(struct string_list *rr) | |
27 | { | |
28 | unsigned char sha1[20]; | |
29 | char buf[PATH_MAX]; | |
30 | FILE *in = fopen(merge_rr_path, "r"); | |
31 | if (!in) | |
32 | return; | |
33 | while (fread(buf, 40, 1, in) == 1) { | |
34 | int i; | |
35 | char *name; | |
36 | if (get_sha1_hex(buf, sha1)) | |
37 | die("corrupt MERGE_RR"); | |
38 | buf[40] = '\0'; | |
39 | name = xstrdup(buf); | |
40 | if (fgetc(in) != '\t') | |
41 | die("corrupt MERGE_RR"); | |
42 | for (i = 0; i < sizeof(buf) && (buf[i] = fgetc(in)); i++) | |
43 | ; /* do nothing */ | |
44 | if (i == sizeof(buf)) | |
45 | die("filename too long"); | |
46 | string_list_insert(buf, rr)->util = name; | |
47 | } | |
48 | fclose(in); | |
49 | } | |
50 | ||
51 | static struct lock_file write_lock; | |
52 | ||
53 | static int write_rr(struct string_list *rr, int out_fd) | |
54 | { | |
55 | int i; | |
56 | for (i = 0; i < rr->nr; i++) { | |
57 | const char *path; | |
58 | int length; | |
59 | if (!rr->items[i].util) | |
60 | continue; | |
61 | path = rr->items[i].string; | |
62 | length = strlen(path) + 1; | |
63 | if (write_in_full(out_fd, rr->items[i].util, 40) != 40 || | |
64 | write_in_full(out_fd, "\t", 1) != 1 || | |
65 | write_in_full(out_fd, path, length) != length) | |
66 | die("unable to write rerere record"); | |
67 | } | |
68 | if (commit_lock_file(&write_lock) != 0) | |
69 | die("unable to write rerere record"); | |
70 | return 0; | |
71 | } | |
72 | ||
73 | static int handle_file(const char *path, | |
74 | unsigned char *sha1, const char *output) | |
75 | { | |
76 | SHA_CTX ctx; | |
77 | char buf[1024]; | |
78 | int hunk = 0, hunk_no = 0; | |
79 | struct strbuf one, two; | |
80 | FILE *f = fopen(path, "r"); | |
81 | FILE *out = NULL; | |
82 | ||
83 | if (!f) | |
84 | return error("Could not open %s", path); | |
85 | ||
86 | if (output) { | |
87 | out = fopen(output, "w"); | |
88 | if (!out) { | |
89 | fclose(f); | |
90 | return error("Could not write %s", output); | |
91 | } | |
92 | } | |
93 | ||
94 | if (sha1) | |
95 | SHA1_Init(&ctx); | |
96 | ||
97 | strbuf_init(&one, 0); | |
98 | strbuf_init(&two, 0); | |
99 | while (fgets(buf, sizeof(buf), f)) { | |
100 | if (!prefixcmp(buf, "<<<<<<< ")) { | |
101 | if (hunk) | |
102 | goto bad; | |
103 | hunk = 1; | |
104 | } else if (!prefixcmp(buf, "=======") && isspace(buf[7])) { | |
105 | if (hunk != 1) | |
106 | goto bad; | |
107 | hunk = 2; | |
108 | } else if (!prefixcmp(buf, ">>>>>>> ")) { | |
109 | if (hunk != 2) | |
110 | goto bad; | |
111 | if (strbuf_cmp(&one, &two) > 0) | |
112 | strbuf_swap(&one, &two); | |
113 | hunk_no++; | |
114 | hunk = 0; | |
115 | if (out) { | |
116 | fputs("<<<<<<<\n", out); | |
117 | fwrite(one.buf, one.len, 1, out); | |
118 | fputs("=======\n", out); | |
119 | fwrite(two.buf, two.len, 1, out); | |
120 | fputs(">>>>>>>\n", out); | |
121 | } | |
122 | if (sha1) { | |
123 | SHA1_Update(&ctx, one.buf ? one.buf : "", | |
124 | one.len + 1); | |
125 | SHA1_Update(&ctx, two.buf ? two.buf : "", | |
126 | two.len + 1); | |
127 | } | |
128 | strbuf_reset(&one); | |
129 | strbuf_reset(&two); | |
130 | } else if (hunk == 1) | |
131 | strbuf_addstr(&one, buf); | |
132 | else if (hunk == 2) | |
133 | strbuf_addstr(&two, buf); | |
134 | else if (out) | |
135 | fputs(buf, out); | |
136 | continue; | |
137 | bad: | |
138 | hunk = 99; /* force error exit */ | |
139 | break; | |
140 | } | |
141 | strbuf_release(&one); | |
142 | strbuf_release(&two); | |
143 | ||
144 | fclose(f); | |
145 | if (out) | |
146 | fclose(out); | |
147 | if (sha1) | |
148 | SHA1_Final(sha1, &ctx); | |
149 | if (hunk) { | |
150 | if (output) | |
151 | unlink(output); | |
152 | return error("Could not parse conflict hunks in %s", path); | |
153 | } | |
154 | return hunk_no; | |
155 | } | |
156 | ||
157 | static int find_conflict(struct string_list *conflict) | |
158 | { | |
159 | int i; | |
160 | if (read_cache() < 0) | |
161 | return error("Could not read index"); | |
162 | for (i = 0; i+1 < active_nr; i++) { | |
163 | struct cache_entry *e2 = active_cache[i]; | |
164 | struct cache_entry *e3 = active_cache[i+1]; | |
165 | if (ce_stage(e2) == 2 && | |
166 | ce_stage(e3) == 3 && | |
167 | ce_same_name(e2, e3) && | |
168 | S_ISREG(e2->ce_mode) && | |
169 | S_ISREG(e3->ce_mode)) { | |
170 | string_list_insert((const char *)e2->name, conflict); | |
171 | i++; /* skip over both #2 and #3 */ | |
172 | } | |
173 | } | |
174 | return 0; | |
175 | } | |
176 | ||
177 | static int merge(const char *name, const char *path) | |
178 | { | |
179 | int ret; | |
180 | mmfile_t cur, base, other; | |
181 | mmbuffer_t result = {NULL, 0}; | |
182 | xpparam_t xpp = {XDF_NEED_MINIMAL}; | |
183 | ||
184 | if (handle_file(path, NULL, rr_path(name, "thisimage")) < 0) | |
185 | return 1; | |
186 | ||
187 | if (read_mmfile(&cur, rr_path(name, "thisimage")) || | |
188 | read_mmfile(&base, rr_path(name, "preimage")) || | |
189 | read_mmfile(&other, rr_path(name, "postimage"))) | |
190 | return 1; | |
191 | ret = xdl_merge(&base, &cur, "", &other, "", | |
192 | &xpp, XDL_MERGE_ZEALOUS, &result); | |
193 | if (!ret) { | |
194 | FILE *f = fopen(path, "w"); | |
195 | if (!f) | |
196 | return error("Could not write to %s", path); | |
197 | fwrite(result.ptr, result.size, 1, f); | |
198 | fclose(f); | |
199 | } | |
200 | ||
201 | free(cur.ptr); | |
202 | free(base.ptr); | |
203 | free(other.ptr); | |
204 | free(result.ptr); | |
205 | ||
206 | return ret; | |
207 | } | |
208 | ||
209 | static struct lock_file index_lock; | |
210 | ||
211 | static int update_paths(struct string_list *update) | |
212 | { | |
213 | int i; | |
214 | int fd = hold_locked_index(&index_lock, 0); | |
215 | int status = 0; | |
216 | ||
217 | if (fd < 0) | |
218 | return -1; | |
219 | ||
220 | for (i = 0; i < update->nr; i++) { | |
221 | struct string_list_item *item = &update->items[i]; | |
222 | if (add_file_to_cache(item->string, ADD_CACHE_IGNORE_ERRORS)) | |
223 | status = -1; | |
224 | } | |
225 | ||
226 | if (!status && active_cache_changed) { | |
227 | if (write_cache(fd, active_cache, active_nr) || | |
228 | commit_locked_index(&index_lock)) | |
229 | die("Unable to write new index file"); | |
230 | } else if (fd >= 0) | |
231 | rollback_lock_file(&index_lock); | |
232 | return status; | |
233 | } | |
234 | ||
235 | static int do_plain_rerere(struct string_list *rr, int fd) | |
236 | { | |
237 | struct string_list conflict = { NULL, 0, 0, 1 }; | |
238 | struct string_list update = { NULL, 0, 0, 1 }; | |
239 | int i; | |
240 | ||
241 | find_conflict(&conflict); | |
242 | ||
243 | /* | |
244 | * MERGE_RR records paths with conflicts immediately after merge | |
245 | * failed. Some of the conflicted paths might have been hand resolved | |
246 | * in the working tree since then, but the initial run would catch all | |
247 | * and register their preimages. | |
248 | */ | |
249 | ||
250 | for (i = 0; i < conflict.nr; i++) { | |
251 | const char *path = conflict.items[i].string; | |
252 | if (!string_list_has_string(rr, path)) { | |
253 | unsigned char sha1[20]; | |
254 | char *hex; | |
255 | int ret; | |
256 | ret = handle_file(path, sha1, NULL); | |
257 | if (ret < 1) | |
258 | continue; | |
259 | hex = xstrdup(sha1_to_hex(sha1)); | |
260 | string_list_insert(path, rr)->util = hex; | |
261 | if (mkdir(git_path("rr-cache/%s", hex), 0755)) | |
262 | continue;; | |
263 | handle_file(path, NULL, rr_path(hex, "preimage")); | |
264 | fprintf(stderr, "Recorded preimage for '%s'\n", path); | |
265 | } | |
266 | } | |
267 | ||
268 | /* | |
269 | * Now some of the paths that had conflicts earlier might have been | |
270 | * hand resolved. Others may be similar to a conflict already that | |
271 | * was resolved before. | |
272 | */ | |
273 | ||
274 | for (i = 0; i < rr->nr; i++) { | |
275 | int ret; | |
276 | const char *path = rr->items[i].string; | |
277 | const char *name = (const char *)rr->items[i].util; | |
278 | ||
279 | if (has_resolution(name)) { | |
280 | if (!merge(name, path)) { | |
281 | if (rerere_autoupdate) | |
282 | string_list_insert(path, &update); | |
283 | fprintf(stderr, | |
284 | "%s '%s' using previous resolution.\n", | |
285 | rerere_autoupdate | |
286 | ? "Staged" : "Resolved", | |
287 | path); | |
288 | goto mark_resolved; | |
289 | } | |
290 | } | |
291 | ||
292 | /* Let's see if we have resolved it. */ | |
293 | ret = handle_file(path, NULL, NULL); | |
294 | if (ret) | |
295 | continue; | |
296 | ||
297 | fprintf(stderr, "Recorded resolution for '%s'.\n", path); | |
298 | copy_file(rr_path(name, "postimage"), path, 0666); | |
299 | mark_resolved: | |
300 | rr->items[i].util = NULL; | |
301 | } | |
302 | ||
303 | if (update.nr) | |
304 | update_paths(&update); | |
305 | ||
306 | return write_rr(rr, fd); | |
307 | } | |
308 | ||
309 | static int git_rerere_config(const char *var, const char *value, void *cb) | |
310 | { | |
311 | if (!strcmp(var, "rerere.enabled")) | |
312 | rerere_enabled = git_config_bool(var, value); | |
313 | else if (!strcmp(var, "rerere.autoupdate")) | |
314 | rerere_autoupdate = git_config_bool(var, value); | |
315 | else | |
316 | return git_default_config(var, value, cb); | |
317 | return 0; | |
318 | } | |
319 | ||
320 | static int is_rerere_enabled(void) | |
321 | { | |
322 | struct stat st; | |
323 | const char *rr_cache; | |
324 | int rr_cache_exists; | |
325 | ||
326 | if (!rerere_enabled) | |
327 | return 0; | |
328 | ||
329 | rr_cache = git_path("rr-cache"); | |
330 | rr_cache_exists = !stat(rr_cache, &st) && S_ISDIR(st.st_mode); | |
331 | if (rerere_enabled < 0) | |
332 | return rr_cache_exists; | |
333 | ||
334 | if (!rr_cache_exists && | |
335 | (mkdir(rr_cache, 0777) || adjust_shared_perm(rr_cache))) | |
336 | die("Could not create directory %s", rr_cache); | |
337 | return 1; | |
338 | } | |
339 | ||
340 | int setup_rerere(struct string_list *merge_rr) | |
341 | { | |
342 | int fd; | |
343 | ||
344 | git_config(git_rerere_config, NULL); | |
345 | if (!is_rerere_enabled()) | |
346 | return -1; | |
347 | ||
348 | merge_rr_path = git_pathdup("MERGE_RR"); | |
349 | fd = hold_lock_file_for_update(&write_lock, merge_rr_path, | |
350 | LOCK_DIE_ON_ERROR); | |
351 | read_rr(merge_rr); | |
352 | return fd; | |
353 | } | |
354 | ||
355 | int rerere(void) | |
356 | { | |
357 | struct string_list merge_rr = { NULL, 0, 0, 1 }; | |
358 | int fd; | |
359 | ||
360 | fd = setup_rerere(&merge_rr); | |
361 | if (fd < 0) | |
362 | return 0; | |
363 | return do_plain_rerere(&merge_rr, fd); | |
364 | } |