gitweb: use new Git::Repo API, and add optional caching
[git/gitweb-caching.git] / rerere.c
blob323e493dafee46c0d3f95e3c4cd9c4c9b463bbef
1 #include "cache.h"
2 #include "string-list.h"
3 #include "rerere.h"
4 #include "xdiff/xdiff.h"
5 #include "xdiff-interface.h"
7 /* if rerere_enabled == -1, fall back to detection of .git/rr-cache */
8 static int rerere_enabled = -1;
10 /* automatically update cleanly resolved paths to the index */
11 static int rerere_autoupdate;
13 static char *merge_rr_path;
15 static const char *rr_path(const char *name, const char *file)
17 return git_path("rr-cache/%s/%s", name, file);
20 static int has_resolution(const char *name)
22 struct stat st;
23 return !stat(rr_path(name, "postimage"), &st);
26 static void read_rr(struct string_list *rr)
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;
48 fclose(in);
51 static struct lock_file write_lock;
53 static int write_rr(struct string_list *rr, int out_fd)
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");
68 if (commit_lock_file(&write_lock) != 0)
69 die("unable to write rerere record");
70 return 0;
73 static int handle_file(const char *path,
74 unsigned char *sha1, const char *output)
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;
83 if (!f)
84 return error("Could not open %s", path);
86 if (output) {
87 out = fopen(output, "w");
88 if (!out) {
89 fclose(f);
90 return error("Could not write %s", output);
94 if (sha1)
95 SHA1_Init(&ctx);
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);
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);
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;
141 strbuf_release(&one);
142 strbuf_release(&two);
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);
154 return hunk_no;
157 static int find_conflict(struct string_list *conflict)
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 */
174 return 0;
177 static int merge(const char *name, const char *path)
179 int ret;
180 mmfile_t cur, base, other;
181 mmbuffer_t result = {NULL, 0};
182 xpparam_t xpp = {XDF_NEED_MINIMAL};
184 if (handle_file(path, NULL, rr_path(name, "thisimage")) < 0)
185 return 1;
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);
201 free(cur.ptr);
202 free(base.ptr);
203 free(other.ptr);
204 free(result.ptr);
206 return ret;
209 static struct lock_file index_lock;
211 static int update_paths(struct string_list *update)
213 int i;
214 int fd = hold_locked_index(&index_lock, 0);
215 int status = 0;
217 if (fd < 0)
218 return -1;
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;
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;
235 static int do_plain_rerere(struct string_list *rr, int fd)
237 struct string_list conflict = { NULL, 0, 0, 1 };
238 struct string_list update = { NULL, 0, 0, 1 };
239 int i;
241 find_conflict(&conflict);
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.
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);
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.
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;
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;
292 /* Let's see if we have resolved it. */
293 ret = handle_file(path, NULL, NULL);
294 if (ret)
295 continue;
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;
303 if (update.nr)
304 update_paths(&update);
306 return write_rr(rr, fd);
309 static int git_rerere_config(const char *var, const char *value, void *cb)
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;
320 static int is_rerere_enabled(void)
322 struct stat st;
323 const char *rr_cache;
324 int rr_cache_exists;
326 if (!rerere_enabled)
327 return 0;
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;
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;
340 int setup_rerere(struct string_list *merge_rr)
342 int fd;
344 git_config(git_rerere_config, NULL);
345 if (!is_rerere_enabled())
346 return -1;
348 merge_rr_path = xstrdup(git_path("MERGE_RR"));
349 fd = hold_lock_file_for_update(&write_lock, merge_rr_path, 1);
350 read_rr(merge_rr);
351 return fd;
354 int rerere(void)
356 struct string_list merge_rr = { NULL, 0, 0, 1 };
357 int fd;
359 fd = setup_rerere(&merge_rr);
360 if (fd < 0)
361 return 0;
362 return do_plain_rerere(&merge_rr, fd);