Merge branch 'dm/svn-remote'
[git/git.git] / rerere.c
CommitLineData
5b2fd956 1#include "cache.h"
c455c87c 2#include "string-list.h"
5b2fd956
SB
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 */
8static int rerere_enabled = -1;
9
10/* automatically update cleanly resolved paths to the index */
11static int rerere_autoupdate;
12
13static char *merge_rr_path;
14
15static const char *rr_path(const char *name, const char *file)
16{
17 return git_path("rr-cache/%s/%s", name, file);
18}
19
20static int has_resolution(const char *name)
21{
22 struct stat st;
23 return !stat(rr_path(name, "postimage"), &st);
24}
25
c455c87c 26static void read_rr(struct string_list *rr)
5b2fd956
SB
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");
c455c87c 46 string_list_insert(buf, rr)->util = name;
5b2fd956
SB
47 }
48 fclose(in);
49}
50
51static struct lock_file write_lock;
52
c455c87c 53static int write_rr(struct string_list *rr, int out_fd)
5b2fd956
SB
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;
c455c87c 61 path = rr->items[i].string;
5b2fd956
SB
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
73static int handle_file(const char *path,
74 unsigned char *sha1, const char *output)
75{
9126f009 76 git_SHA_CTX ctx;
5b2fd956 77 char buf[1024];
cc58d7df
JH
78 int hunk_no = 0;
79 enum {
387c9d49 80 RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2, RR_ORIGINAL,
cc58d7df 81 } hunk = RR_CONTEXT;
f285a2d7 82 struct strbuf one = STRBUF_INIT, two = STRBUF_INIT;
5b2fd956
SB
83 FILE *f = fopen(path, "r");
84 FILE *out = NULL;
85
86 if (!f)
87 return error("Could not open %s", path);
88
89 if (output) {
90 out = fopen(output, "w");
91 if (!out) {
92 fclose(f);
93 return error("Could not write %s", output);
94 }
95 }
96
97 if (sha1)
9126f009 98 git_SHA1_Init(&ctx);
5b2fd956 99
5b2fd956
SB
100 while (fgets(buf, sizeof(buf), f)) {
101 if (!prefixcmp(buf, "<<<<<<< ")) {
cc58d7df 102 if (hunk != RR_CONTEXT)
5b2fd956 103 goto bad;
cc58d7df 104 hunk = RR_SIDE_1;
387c9d49 105 } else if (!prefixcmp(buf, "|||||||") && isspace(buf[7])) {
cc58d7df 106 if (hunk != RR_SIDE_1)
5b2fd956 107 goto bad;
387c9d49 108 hunk = RR_ORIGINAL;
5b2fd956 109 } else if (!prefixcmp(buf, "=======") && isspace(buf[7])) {
387c9d49 110 if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
5b2fd956 111 goto bad;
cc58d7df 112 hunk = RR_SIDE_2;
5b2fd956 113 } else if (!prefixcmp(buf, ">>>>>>> ")) {
cc58d7df 114 if (hunk != RR_SIDE_2)
5b2fd956
SB
115 goto bad;
116 if (strbuf_cmp(&one, &two) > 0)
117 strbuf_swap(&one, &two);
118 hunk_no++;
cc58d7df 119 hunk = RR_CONTEXT;
5b2fd956
SB
120 if (out) {
121 fputs("<<<<<<<\n", out);
122 fwrite(one.buf, one.len, 1, out);
123 fputs("=======\n", out);
124 fwrite(two.buf, two.len, 1, out);
125 fputs(">>>>>>>\n", out);
126 }
127 if (sha1) {
9126f009 128 git_SHA1_Update(&ctx, one.buf ? one.buf : "",
5b2fd956 129 one.len + 1);
9126f009 130 git_SHA1_Update(&ctx, two.buf ? two.buf : "",
5b2fd956
SB
131 two.len + 1);
132 }
133 strbuf_reset(&one);
134 strbuf_reset(&two);
cc58d7df 135 } else if (hunk == RR_SIDE_1)
5b2fd956 136 strbuf_addstr(&one, buf);
387c9d49
JH
137 else if (hunk == RR_ORIGINAL)
138 ; /* discard */
cc58d7df 139 else if (hunk == RR_SIDE_2)
5b2fd956
SB
140 strbuf_addstr(&two, buf);
141 else if (out)
142 fputs(buf, out);
143 continue;
144 bad:
145 hunk = 99; /* force error exit */
146 break;
147 }
148 strbuf_release(&one);
149 strbuf_release(&two);
150
151 fclose(f);
152 if (out)
153 fclose(out);
154 if (sha1)
9126f009 155 git_SHA1_Final(sha1, &ctx);
cc58d7df 156 if (hunk != RR_CONTEXT) {
5b2fd956
SB
157 if (output)
158 unlink(output);
159 return error("Could not parse conflict hunks in %s", path);
160 }
161 return hunk_no;
162}
163
c455c87c 164static int find_conflict(struct string_list *conflict)
5b2fd956
SB
165{
166 int i;
167 if (read_cache() < 0)
168 return error("Could not read index");
169 for (i = 0; i+1 < active_nr; i++) {
170 struct cache_entry *e2 = active_cache[i];
171 struct cache_entry *e3 = active_cache[i+1];
172 if (ce_stage(e2) == 2 &&
173 ce_stage(e3) == 3 &&
174 ce_same_name(e2, e3) &&
175 S_ISREG(e2->ce_mode) &&
176 S_ISREG(e3->ce_mode)) {
c455c87c 177 string_list_insert((const char *)e2->name, conflict);
5b2fd956
SB
178 i++; /* skip over both #2 and #3 */
179 }
180 }
181 return 0;
182}
183
184static int merge(const char *name, const char *path)
185{
186 int ret;
187 mmfile_t cur, base, other;
188 mmbuffer_t result = {NULL, 0};
189 xpparam_t xpp = {XDF_NEED_MINIMAL};
190
191 if (handle_file(path, NULL, rr_path(name, "thisimage")) < 0)
192 return 1;
193
194 if (read_mmfile(&cur, rr_path(name, "thisimage")) ||
195 read_mmfile(&base, rr_path(name, "preimage")) ||
196 read_mmfile(&other, rr_path(name, "postimage")))
197 return 1;
198 ret = xdl_merge(&base, &cur, "", &other, "",
199 &xpp, XDL_MERGE_ZEALOUS, &result);
200 if (!ret) {
201 FILE *f = fopen(path, "w");
202 if (!f)
203 return error("Could not write to %s", path);
204 fwrite(result.ptr, result.size, 1, f);
205 fclose(f);
206 }
207
208 free(cur.ptr);
209 free(base.ptr);
210 free(other.ptr);
211 free(result.ptr);
212
213 return ret;
214}
215
216static struct lock_file index_lock;
217
c455c87c 218static int update_paths(struct string_list *update)
5b2fd956
SB
219{
220 int i;
221 int fd = hold_locked_index(&index_lock, 0);
222 int status = 0;
223
224 if (fd < 0)
225 return -1;
226
227 for (i = 0; i < update->nr; i++) {
c455c87c
JS
228 struct string_list_item *item = &update->items[i];
229 if (add_file_to_cache(item->string, ADD_CACHE_IGNORE_ERRORS))
5b2fd956
SB
230 status = -1;
231 }
232
233 if (!status && active_cache_changed) {
234 if (write_cache(fd, active_cache, active_nr) ||
235 commit_locked_index(&index_lock))
236 die("Unable to write new index file");
237 } else if (fd >= 0)
238 rollback_lock_file(&index_lock);
239 return status;
240}
241
c455c87c 242static int do_plain_rerere(struct string_list *rr, int fd)
5b2fd956 243{
c455c87c
JS
244 struct string_list conflict = { NULL, 0, 0, 1 };
245 struct string_list update = { NULL, 0, 0, 1 };
5b2fd956
SB
246 int i;
247
248 find_conflict(&conflict);
249
250 /*
251 * MERGE_RR records paths with conflicts immediately after merge
252 * failed. Some of the conflicted paths might have been hand resolved
253 * in the working tree since then, but the initial run would catch all
254 * and register their preimages.
255 */
256
257 for (i = 0; i < conflict.nr; i++) {
c455c87c
JS
258 const char *path = conflict.items[i].string;
259 if (!string_list_has_string(rr, path)) {
5b2fd956
SB
260 unsigned char sha1[20];
261 char *hex;
262 int ret;
263 ret = handle_file(path, sha1, NULL);
264 if (ret < 1)
265 continue;
266 hex = xstrdup(sha1_to_hex(sha1));
c455c87c 267 string_list_insert(path, rr)->util = hex;
5b2fd956
SB
268 if (mkdir(git_path("rr-cache/%s", hex), 0755))
269 continue;;
270 handle_file(path, NULL, rr_path(hex, "preimage"));
271 fprintf(stderr, "Recorded preimage for '%s'\n", path);
272 }
273 }
274
275 /*
276 * Now some of the paths that had conflicts earlier might have been
277 * hand resolved. Others may be similar to a conflict already that
278 * was resolved before.
279 */
280
281 for (i = 0; i < rr->nr; i++) {
282 int ret;
c455c87c 283 const char *path = rr->items[i].string;
5b2fd956
SB
284 const char *name = (const char *)rr->items[i].util;
285
286 if (has_resolution(name)) {
287 if (!merge(name, path)) {
5b2fd956 288 if (rerere_autoupdate)
c455c87c 289 string_list_insert(path, &update);
9196e825
JH
290 fprintf(stderr,
291 "%s '%s' using previous resolution.\n",
292 rerere_autoupdate
293 ? "Staged" : "Resolved",
294 path);
5b2fd956
SB
295 goto mark_resolved;
296 }
297 }
298
299 /* Let's see if we have resolved it. */
300 ret = handle_file(path, NULL, NULL);
301 if (ret)
302 continue;
303
304 fprintf(stderr, "Recorded resolution for '%s'.\n", path);
305 copy_file(rr_path(name, "postimage"), path, 0666);
306 mark_resolved:
307 rr->items[i].util = NULL;
308 }
309
310 if (update.nr)
311 update_paths(&update);
312
313 return write_rr(rr, fd);
314}
315
316static int git_rerere_config(const char *var, const char *value, void *cb)
317{
318 if (!strcmp(var, "rerere.enabled"))
319 rerere_enabled = git_config_bool(var, value);
320 else if (!strcmp(var, "rerere.autoupdate"))
321 rerere_autoupdate = git_config_bool(var, value);
322 else
323 return git_default_config(var, value, cb);
324 return 0;
325}
326
327static int is_rerere_enabled(void)
328{
5b2fd956
SB
329 const char *rr_cache;
330 int rr_cache_exists;
331
332 if (!rerere_enabled)
333 return 0;
334
335 rr_cache = git_path("rr-cache");
90b4a71c 336 rr_cache_exists = is_directory(rr_cache);
5b2fd956
SB
337 if (rerere_enabled < 0)
338 return rr_cache_exists;
339
340 if (!rr_cache_exists &&
341 (mkdir(rr_cache, 0777) || adjust_shared_perm(rr_cache)))
342 die("Could not create directory %s", rr_cache);
343 return 1;
344}
345
c455c87c 346int setup_rerere(struct string_list *merge_rr)
5b2fd956
SB
347{
348 int fd;
349
350 git_config(git_rerere_config, NULL);
351 if (!is_rerere_enabled())
352 return -1;
353
a4f34cbb 354 merge_rr_path = git_pathdup("MERGE_RR");
acd3b9ec
JH
355 fd = hold_lock_file_for_update(&write_lock, merge_rr_path,
356 LOCK_DIE_ON_ERROR);
5b2fd956
SB
357 read_rr(merge_rr);
358 return fd;
359}
360
361int rerere(void)
362{
c455c87c 363 struct string_list merge_rr = { NULL, 0, 0, 1 };
5b2fd956
SB
364 int fd;
365
366 fd = setup_rerere(&merge_rr);
367 if (fd < 0)
368 return 0;
369 return do_plain_rerere(&merge_rr, fd);
370}