rerere.c: use symbolic constants to keep track of parsing states
[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{
76 SHA_CTX ctx;
77 char buf[1024];
cc58d7df
JH
78 int hunk_no = 0;
79 enum {
80 RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2,
81 } hunk = RR_CONTEXT;
5b2fd956
SB
82 struct strbuf one, two;
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)
98 SHA1_Init(&ctx);
99
100 strbuf_init(&one, 0);
101 strbuf_init(&two, 0);
102 while (fgets(buf, sizeof(buf), f)) {
103 if (!prefixcmp(buf, "<<<<<<< ")) {
cc58d7df 104 if (hunk != RR_CONTEXT)
5b2fd956 105 goto bad;
cc58d7df 106 hunk = RR_SIDE_1;
5b2fd956 107 } else if (!prefixcmp(buf, "=======") && isspace(buf[7])) {
cc58d7df 108 if (hunk != RR_SIDE_1)
5b2fd956 109 goto bad;
cc58d7df 110 hunk = RR_SIDE_2;
5b2fd956 111 } else if (!prefixcmp(buf, ">>>>>>> ")) {
cc58d7df 112 if (hunk != RR_SIDE_2)
5b2fd956
SB
113 goto bad;
114 if (strbuf_cmp(&one, &two) > 0)
115 strbuf_swap(&one, &two);
116 hunk_no++;
cc58d7df 117 hunk = RR_CONTEXT;
5b2fd956
SB
118 if (out) {
119 fputs("<<<<<<<\n", out);
120 fwrite(one.buf, one.len, 1, out);
121 fputs("=======\n", out);
122 fwrite(two.buf, two.len, 1, out);
123 fputs(">>>>>>>\n", out);
124 }
125 if (sha1) {
126 SHA1_Update(&ctx, one.buf ? one.buf : "",
127 one.len + 1);
128 SHA1_Update(&ctx, two.buf ? two.buf : "",
129 two.len + 1);
130 }
131 strbuf_reset(&one);
132 strbuf_reset(&two);
cc58d7df 133 } else if (hunk == RR_SIDE_1)
5b2fd956 134 strbuf_addstr(&one, buf);
cc58d7df 135 else if (hunk == RR_SIDE_2)
5b2fd956
SB
136 strbuf_addstr(&two, buf);
137 else if (out)
138 fputs(buf, out);
139 continue;
140 bad:
141 hunk = 99; /* force error exit */
142 break;
143 }
144 strbuf_release(&one);
145 strbuf_release(&two);
146
147 fclose(f);
148 if (out)
149 fclose(out);
150 if (sha1)
151 SHA1_Final(sha1, &ctx);
cc58d7df 152 if (hunk != RR_CONTEXT) {
5b2fd956
SB
153 if (output)
154 unlink(output);
155 return error("Could not parse conflict hunks in %s", path);
156 }
157 return hunk_no;
158}
159
c455c87c 160static int find_conflict(struct string_list *conflict)
5b2fd956
SB
161{
162 int i;
163 if (read_cache() < 0)
164 return error("Could not read index");
165 for (i = 0; i+1 < active_nr; i++) {
166 struct cache_entry *e2 = active_cache[i];
167 struct cache_entry *e3 = active_cache[i+1];
168 if (ce_stage(e2) == 2 &&
169 ce_stage(e3) == 3 &&
170 ce_same_name(e2, e3) &&
171 S_ISREG(e2->ce_mode) &&
172 S_ISREG(e3->ce_mode)) {
c455c87c 173 string_list_insert((const char *)e2->name, conflict);
5b2fd956
SB
174 i++; /* skip over both #2 and #3 */
175 }
176 }
177 return 0;
178}
179
180static int merge(const char *name, const char *path)
181{
182 int ret;
183 mmfile_t cur, base, other;
184 mmbuffer_t result = {NULL, 0};
185 xpparam_t xpp = {XDF_NEED_MINIMAL};
186
187 if (handle_file(path, NULL, rr_path(name, "thisimage")) < 0)
188 return 1;
189
190 if (read_mmfile(&cur, rr_path(name, "thisimage")) ||
191 read_mmfile(&base, rr_path(name, "preimage")) ||
192 read_mmfile(&other, rr_path(name, "postimage")))
193 return 1;
194 ret = xdl_merge(&base, &cur, "", &other, "",
195 &xpp, XDL_MERGE_ZEALOUS, &result);
196 if (!ret) {
197 FILE *f = fopen(path, "w");
198 if (!f)
199 return error("Could not write to %s", path);
200 fwrite(result.ptr, result.size, 1, f);
201 fclose(f);
202 }
203
204 free(cur.ptr);
205 free(base.ptr);
206 free(other.ptr);
207 free(result.ptr);
208
209 return ret;
210}
211
212static struct lock_file index_lock;
213
c455c87c 214static int update_paths(struct string_list *update)
5b2fd956
SB
215{
216 int i;
217 int fd = hold_locked_index(&index_lock, 0);
218 int status = 0;
219
220 if (fd < 0)
221 return -1;
222
223 for (i = 0; i < update->nr; i++) {
c455c87c
JS
224 struct string_list_item *item = &update->items[i];
225 if (add_file_to_cache(item->string, ADD_CACHE_IGNORE_ERRORS))
5b2fd956
SB
226 status = -1;
227 }
228
229 if (!status && active_cache_changed) {
230 if (write_cache(fd, active_cache, active_nr) ||
231 commit_locked_index(&index_lock))
232 die("Unable to write new index file");
233 } else if (fd >= 0)
234 rollback_lock_file(&index_lock);
235 return status;
236}
237
c455c87c 238static int do_plain_rerere(struct string_list *rr, int fd)
5b2fd956 239{
c455c87c
JS
240 struct string_list conflict = { NULL, 0, 0, 1 };
241 struct string_list update = { NULL, 0, 0, 1 };
5b2fd956
SB
242 int i;
243
244 find_conflict(&conflict);
245
246 /*
247 * MERGE_RR records paths with conflicts immediately after merge
248 * failed. Some of the conflicted paths might have been hand resolved
249 * in the working tree since then, but the initial run would catch all
250 * and register their preimages.
251 */
252
253 for (i = 0; i < conflict.nr; i++) {
c455c87c
JS
254 const char *path = conflict.items[i].string;
255 if (!string_list_has_string(rr, path)) {
5b2fd956
SB
256 unsigned char sha1[20];
257 char *hex;
258 int ret;
259 ret = handle_file(path, sha1, NULL);
260 if (ret < 1)
261 continue;
262 hex = xstrdup(sha1_to_hex(sha1));
c455c87c 263 string_list_insert(path, rr)->util = hex;
5b2fd956
SB
264 if (mkdir(git_path("rr-cache/%s", hex), 0755))
265 continue;;
266 handle_file(path, NULL, rr_path(hex, "preimage"));
267 fprintf(stderr, "Recorded preimage for '%s'\n", path);
268 }
269 }
270
271 /*
272 * Now some of the paths that had conflicts earlier might have been
273 * hand resolved. Others may be similar to a conflict already that
274 * was resolved before.
275 */
276
277 for (i = 0; i < rr->nr; i++) {
278 int ret;
c455c87c 279 const char *path = rr->items[i].string;
5b2fd956
SB
280 const char *name = (const char *)rr->items[i].util;
281
282 if (has_resolution(name)) {
283 if (!merge(name, path)) {
5b2fd956 284 if (rerere_autoupdate)
c455c87c 285 string_list_insert(path, &update);
9196e825
JH
286 fprintf(stderr,
287 "%s '%s' using previous resolution.\n",
288 rerere_autoupdate
289 ? "Staged" : "Resolved",
290 path);
5b2fd956
SB
291 goto mark_resolved;
292 }
293 }
294
295 /* Let's see if we have resolved it. */
296 ret = handle_file(path, NULL, NULL);
297 if (ret)
298 continue;
299
300 fprintf(stderr, "Recorded resolution for '%s'.\n", path);
301 copy_file(rr_path(name, "postimage"), path, 0666);
302 mark_resolved:
303 rr->items[i].util = NULL;
304 }
305
306 if (update.nr)
307 update_paths(&update);
308
309 return write_rr(rr, fd);
310}
311
312static int git_rerere_config(const char *var, const char *value, void *cb)
313{
314 if (!strcmp(var, "rerere.enabled"))
315 rerere_enabled = git_config_bool(var, value);
316 else if (!strcmp(var, "rerere.autoupdate"))
317 rerere_autoupdate = git_config_bool(var, value);
318 else
319 return git_default_config(var, value, cb);
320 return 0;
321}
322
323static int is_rerere_enabled(void)
324{
325 struct stat st;
326 const char *rr_cache;
327 int rr_cache_exists;
328
329 if (!rerere_enabled)
330 return 0;
331
332 rr_cache = git_path("rr-cache");
333 rr_cache_exists = !stat(rr_cache, &st) && S_ISDIR(st.st_mode);
334 if (rerere_enabled < 0)
335 return rr_cache_exists;
336
337 if (!rr_cache_exists &&
338 (mkdir(rr_cache, 0777) || adjust_shared_perm(rr_cache)))
339 die("Could not create directory %s", rr_cache);
340 return 1;
341}
342
c455c87c 343int setup_rerere(struct string_list *merge_rr)
5b2fd956
SB
344{
345 int fd;
346
347 git_config(git_rerere_config, NULL);
348 if (!is_rerere_enabled())
349 return -1;
350
ebcffb1d 351 merge_rr_path = xstrdup(git_path("MERGE_RR"));
5b2fd956
SB
352 fd = hold_lock_file_for_update(&write_lock, merge_rr_path, 1);
353 read_rr(merge_rr);
354 return fd;
355}
356
357int rerere(void)
358{
c455c87c 359 struct string_list merge_rr = { NULL, 0, 0, 1 };
5b2fd956
SB
360 int fd;
361
362 fd = setup_rerere(&merge_rr);
363 if (fd < 0)
364 return 0;
365 return do_plain_rerere(&merge_rr, fd);
366}