Merge branch 'maint'
[git] / builtin-rerere.c
1 #include "cache.h"
2 #include "path-list.h"
3 #include "xdiff/xdiff.h"
4 #include "xdiff-interface.h"
5
6 #include <time.h>
7
8 static const char git_rerere_usage[] =
9 "git-rerere [clear | status | diff | gc]";
10
11 /* these values are days */
12 static int cutoff_noresolve = 15;
13 static int cutoff_resolve = 60;
14
15 static char *merge_rr_path;
16
17 static const char *rr_path(const char *name, const char *file)
18 {
19         return git_path("rr-cache/%s/%s", name, file);
20 }
21
22 static void read_rr(struct path_list *rr)
23 {
24         unsigned char sha1[20];
25         char buf[PATH_MAX];
26         FILE *in = fopen(merge_rr_path, "r");
27         if (!in)
28                 return;
29         while (fread(buf, 40, 1, in) == 1) {
30                 int i;
31                 char *name;
32                 if (get_sha1_hex(buf, sha1))
33                         die("corrupt MERGE_RR");
34                 buf[40] = '\0';
35                 name = xstrdup(buf);
36                 if (fgetc(in) != '\t')
37                         die("corrupt MERGE_RR");
38                 for (i = 0; i < sizeof(buf) && (buf[i] = fgetc(in)); i++)
39                         ; /* do nothing */
40                 if (i == sizeof(buf))
41                         die("filename too long");
42                 path_list_insert(buf, rr)->util = xstrdup(name);
43         }
44         fclose(in);
45 }
46
47 static struct lock_file write_lock;
48
49 static int write_rr(struct path_list *rr, int out_fd)
50 {
51         int i;
52         for (i = 0; i < rr->nr; i++) {
53                 const char *path = rr->items[i].path;
54                 int length = strlen(path) + 1;
55                 if (write_in_full(out_fd, rr->items[i].util, 40) != 40 ||
56                     write_in_full(out_fd, "\t", 1) != 1 ||
57                     write_in_full(out_fd, path, length) != length)
58                         die("unable to write rerere record");
59         }
60         close(out_fd);
61         return commit_lock_file(&write_lock);
62 }
63
64 struct buffer {
65         char *ptr;
66         int nr, alloc;
67 };
68
69 static void append_line(struct buffer *buffer, const char *line)
70 {
71         int len = strlen(line);
72
73         if (buffer->nr + len > buffer->alloc) {
74                 buffer->alloc = alloc_nr(buffer->nr + len);
75                 buffer->ptr = xrealloc(buffer->ptr, buffer->alloc);
76         }
77         memcpy(buffer->ptr + buffer->nr, line, len);
78         buffer->nr += len;
79 }
80
81 static int handle_file(const char *path,
82          unsigned char *sha1, const char *output)
83 {
84         SHA_CTX ctx;
85         char buf[1024];
86         int hunk = 0, hunk_no = 0;
87         struct buffer minus = { NULL, 0, 0 }, plus = { NULL, 0, 0 };
88         struct buffer *one = &minus, *two = &plus;
89         FILE *f = fopen(path, "r");
90         FILE *out;
91
92         if (!f)
93                 return error("Could not open %s", path);
94
95         if (output) {
96                 out = fopen(output, "w");
97                 if (!out) {
98                         fclose(f);
99                         return error("Could not write %s", output);
100                 }
101         } else
102                 out = NULL;
103
104         if (sha1)
105                 SHA1_Init(&ctx);
106
107         while (fgets(buf, sizeof(buf), f)) {
108                 if (!prefixcmp(buf, "<<<<<<< "))
109                         hunk = 1;
110                 else if (!prefixcmp(buf, "======="))
111                         hunk = 2;
112                 else if (!prefixcmp(buf, ">>>>>>> ")) {
113                         hunk_no++;
114                         hunk = 0;
115                         if (memcmp(one->ptr, two->ptr, one->nr < two->nr ?
116                                                 one->nr : two->nr) > 0) {
117                                 struct buffer *swap = one;
118                                 one = two;
119                                 two = swap;
120                         }
121                         if (out) {
122                                 fputs("<<<<<<<\n", out);
123                                 fwrite(one->ptr, one->nr, 1, out);
124                                 fputs("=======\n", out);
125                                 fwrite(two->ptr, two->nr, 1, out);
126                                 fputs(">>>>>>>\n", out);
127                         }
128                         if (sha1) {
129                                 SHA1_Update(&ctx, one->ptr, one->nr);
130                                 SHA1_Update(&ctx, "\0", 1);
131                                 SHA1_Update(&ctx, two->ptr, two->nr);
132                                 SHA1_Update(&ctx, "\0", 1);
133                         }
134                 } else if (hunk == 1)
135                         append_line(one, buf);
136                 else if (hunk == 2)
137                         append_line(two, buf);
138                 else if (out)
139                         fputs(buf, out);
140         }
141
142         fclose(f);
143         if (out)
144                 fclose(out);
145         if (sha1)
146                 SHA1_Final(sha1, &ctx);
147         return hunk_no;
148 }
149
150 static int find_conflict(struct path_list *conflict)
151 {
152         int i;
153         if (read_cache() < 0)
154                 return error("Could not read index");
155         for (i = 0; i + 2 < active_nr; i++) {
156                 struct cache_entry *e1 = active_cache[i];
157                 struct cache_entry *e2 = active_cache[i+1];
158                 struct cache_entry *e3 = active_cache[i+2];
159                 if (ce_stage(e1) == 1 &&
160                     ce_stage(e2) == 2 &&
161                     ce_stage(e3) == 3 &&
162                     ce_same_name(e1, e2) && ce_same_name(e1, e3) &&
163                     S_ISREG(ntohl(e1->ce_mode)) &&
164                     S_ISREG(ntohl(e2->ce_mode)) &&
165                     S_ISREG(ntohl(e3->ce_mode))) {
166                         path_list_insert((const char *)e1->name, conflict);
167                         i += 2;
168                 }
169         }
170         return 0;
171 }
172
173 static int merge(const char *name, const char *path)
174 {
175         int ret;
176         mmfile_t cur, base, other;
177         mmbuffer_t result = {NULL, 0};
178         xpparam_t xpp = {XDF_NEED_MINIMAL};
179
180         if (handle_file(path, NULL, rr_path(name, "thisimage")) < 0)
181                 return 1;
182
183         if (read_mmfile(&cur, rr_path(name, "thisimage")) ||
184                         read_mmfile(&base, rr_path(name, "preimage")) ||
185                         read_mmfile(&other, rr_path(name, "postimage")))
186                 return 1;
187         ret = xdl_merge(&base, &cur, "", &other, "",
188                         &xpp, XDL_MERGE_ZEALOUS, &result);
189         if (!ret) {
190                 FILE *f = fopen(path, "w");
191                 if (!f)
192                         return error("Could not write to %s", path);
193                 fwrite(result.ptr, result.size, 1, f);
194                 fclose(f);
195         }
196
197         free(cur.ptr);
198         free(base.ptr);
199         free(other.ptr);
200         free(result.ptr);
201
202         return ret;
203 }
204
205 static void unlink_rr_item(const char *name)
206 {
207         unlink(rr_path(name, "thisimage"));
208         unlink(rr_path(name, "preimage"));
209         unlink(rr_path(name, "postimage"));
210         rmdir(git_path("rr-cache/%s", name));
211 }
212
213 static void garbage_collect(struct path_list *rr)
214 {
215         struct path_list to_remove = { NULL, 0, 0, 1 };
216         char buf[1024];
217         DIR *dir;
218         struct dirent *e;
219         int len, i, cutoff;
220         time_t now = time(NULL), then;
221
222         strlcpy(buf, git_path("rr-cache"), sizeof(buf));
223         len = strlen(buf);
224         dir = opendir(buf);
225         strcpy(buf + len++, "/");
226         while ((e = readdir(dir))) {
227                 const char *name = e->d_name;
228                 struct stat st;
229                 if (name[0] == '.' && (name[1] == '\0' ||
230                                         (name[1] == '.' && name[2] == '\0')))
231                         continue;
232                 i = snprintf(buf + len, sizeof(buf) - len, "%s", name);
233                 strlcpy(buf + len + i, "/preimage", sizeof(buf) - len - i);
234                 if (stat(buf, &st))
235                         continue;
236                 then = st.st_mtime;
237                 strlcpy(buf + len + i, "/postimage", sizeof(buf) - len - i);
238                 cutoff = stat(buf, &st) ? cutoff_noresolve : cutoff_resolve;
239                 if (then < now - cutoff * 86400) {
240                         buf[len + i] = '\0';
241                         path_list_insert(xstrdup(name), &to_remove);
242                 }
243         }
244         for (i = 0; i < to_remove.nr; i++)
245                 unlink_rr_item(to_remove.items[i].path);
246         path_list_clear(&to_remove, 0);
247 }
248
249 static int outf(void *dummy, mmbuffer_t *ptr, int nbuf)
250 {
251         int i;
252         for (i = 0; i < nbuf; i++)
253                 if (write_in_full(1, ptr[i].ptr, ptr[i].size) != ptr[i].size)
254                         return -1;
255         return 0;
256 }
257
258 static int diff_two(const char *file1, const char *label1,
259                 const char *file2, const char *label2)
260 {
261         xpparam_t xpp;
262         xdemitconf_t xecfg;
263         xdemitcb_t ecb;
264         mmfile_t minus, plus;
265
266         if (read_mmfile(&minus, file1) || read_mmfile(&plus, file2))
267                 return 1;
268
269         printf("--- a/%s\n+++ b/%s\n", label1, label2);
270         fflush(stdout);
271         xpp.flags = XDF_NEED_MINIMAL;
272         xecfg.ctxlen = 3;
273         xecfg.flags = 0;
274         ecb.outf = outf;
275         xdl_diff(&minus, &plus, &xpp, &xecfg, &ecb);
276
277         free(minus.ptr);
278         free(plus.ptr);
279         return 0;
280 }
281
282 static int copy_file(const char *src, const char *dest)
283 {
284         FILE *in, *out;
285         char buffer[32768];
286         int count;
287
288         if (!(in = fopen(src, "r")))
289                 return error("Could not open %s", src);
290         if (!(out = fopen(dest, "w")))
291                 return error("Could not open %s", dest);
292         while ((count = fread(buffer, 1, sizeof(buffer), in)))
293                 fwrite(buffer, 1, count, out);
294         fclose(in);
295         fclose(out);
296         return 0;
297 }
298
299 static int do_plain_rerere(struct path_list *rr, int fd)
300 {
301         struct path_list conflict = { NULL, 0, 0, 1 };
302         int i;
303
304         find_conflict(&conflict);
305
306         /*
307          * MERGE_RR records paths with conflicts immediately after merge
308          * failed.  Some of the conflicted paths might have been hand resolved
309          * in the working tree since then, but the initial run would catch all
310          * and register their preimages.
311          */
312
313         for (i = 0; i < conflict.nr; i++) {
314                 const char *path = conflict.items[i].path;
315                 if (!path_list_has_path(rr, path)) {
316                         unsigned char sha1[20];
317                         char *hex;
318                         int ret;
319                         ret = handle_file(path, sha1, NULL);
320                         if (ret < 1)
321                                 continue;
322                         hex = xstrdup(sha1_to_hex(sha1));
323                         path_list_insert(path, rr)->util = hex;
324                         if (mkdir(git_path("rr-cache/%s", hex), 0755))
325                                 continue;;
326                         handle_file(path, NULL, rr_path(hex, "preimage"));
327                         fprintf(stderr, "Recorded preimage for '%s'\n", path);
328                 }
329         }
330
331         /*
332          * Now some of the paths that had conflicts earlier might have been
333          * hand resolved.  Others may be similar to a conflict already that
334          * was resolved before.
335          */
336
337         for (i = 0; i < rr->nr; i++) {
338                 struct stat st;
339                 int ret;
340                 const char *path = rr->items[i].path;
341                 const char *name = (const char *)rr->items[i].util;
342
343                 if (!stat(rr_path(name, "preimage"), &st) &&
344                                 !stat(rr_path(name, "postimage"), &st)) {
345                         if (!merge(name, path)) {
346                                 fprintf(stderr, "Resolved '%s' using "
347                                                 "previous resolution.\n", path);
348                                 goto tail_optimization;
349                         }
350                 }
351
352                 /* Let's see if we have resolved it. */
353                 ret = handle_file(path, NULL, NULL);
354                 if (ret)
355                         continue;
356
357                 fprintf(stderr, "Recorded resolution for '%s'.\n", path);
358                 copy_file(path, rr_path(name, "postimage"));
359 tail_optimization:
360                 if (i < rr->nr - 1)
361                         memmove(rr->items + i,
362                                 rr->items + i + 1,
363                                 sizeof(rr->items[0]) * (rr->nr - i - 1));
364                 rr->nr--;
365                 i--;
366         }
367
368         return write_rr(rr, fd);
369 }
370
371 static int git_rerere_config(const char *var, const char *value)
372 {
373         if (!strcmp(var, "gc.rerereresolved"))
374                 cutoff_resolve = git_config_int(var, value);
375         else if (!strcmp(var, "gc.rerereunresolved"))
376                 cutoff_noresolve = git_config_int(var, value);
377         else
378                 return git_default_config(var, value);
379         return 0;
380 }
381
382 int cmd_rerere(int argc, const char **argv, const char *prefix)
383 {
384         struct path_list merge_rr = { NULL, 0, 0, 1 };
385         int i, fd = -1;
386         struct stat st;
387
388         if (stat(git_path("rr-cache"), &st) || !S_ISDIR(st.st_mode))
389                 return 0;
390
391         git_config(git_rerere_config);
392
393         merge_rr_path = xstrdup(git_path("rr-cache/MERGE_RR"));
394         fd = hold_lock_file_for_update(&write_lock, merge_rr_path, 1);
395         read_rr(&merge_rr);
396
397         if (argc < 2)
398                 return do_plain_rerere(&merge_rr, fd);
399         else if (!strcmp(argv[1], "clear")) {
400                 for (i = 0; i < merge_rr.nr; i++) {
401                         const char *name = (const char *)merge_rr.items[i].util;
402                         if (!stat(git_path("rr-cache/%s", name), &st) &&
403                                         S_ISDIR(st.st_mode) &&
404                                         stat(rr_path(name, "postimage"), &st))
405                                 unlink_rr_item(name);
406                 }
407                 unlink(merge_rr_path);
408         } else if (!strcmp(argv[1], "gc"))
409                 garbage_collect(&merge_rr);
410         else if (!strcmp(argv[1], "status"))
411                 for (i = 0; i < merge_rr.nr; i++)
412                         printf("%s\n", merge_rr.items[i].path);
413         else if (!strcmp(argv[1], "diff"))
414                 for (i = 0; i < merge_rr.nr; i++) {
415                         const char *path = merge_rr.items[i].path;
416                         const char *name = (const char *)merge_rr.items[i].util;
417                         diff_two(rr_path(name, "preimage"), path, path, path);
418                 }
419         else
420                 usage(git_rerere_usage);
421
422         path_list_clear(&merge_rr, 1);
423         return 0;
424 }
425