1#include "builtin.h"
2#include "cache.h"
3#include "path-list.h"
4#include "xdiff/xdiff.h"
5#include "xdiff-interface.h"
6#include <time.h>
8static const char git_rerere_usage[] =
10"git-rerere [clear | status | diff | gc]";
11/* these values are days */
13static int cutoff_noresolve = 15;
14static int cutoff_resolve = 60;
15/* if rerere_enabled == -1, fall back to detection of .git/rr-cache */
17static int rerere_enabled = -1;
18static char *merge_rr_path;
20static const char *rr_path(const char *name, const char *file)
22{
23 return git_path("rr-cache/%s/%s", name, file);
24}
25static void read_rr(struct path_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 path_list_insert(buf, rr)->util = xstrdup(name);
47 }
48 fclose(in);
49}
50static struct lock_file write_lock;
52static int write_rr(struct path_list *rr, int out_fd)
54{
55 int i;
56 for (i = 0; i < rr->nr; i++) {
57 const char *path = rr->items[i].path;
58 int length = strlen(path) + 1;
59 if (write_in_full(out_fd, rr->items[i].util, 40) != 40 ||
60 write_in_full(out_fd, "\t", 1) != 1 ||
61 write_in_full(out_fd, path, length) != length)
62 die("unable to write rerere record");
63 }
64 if (close(out_fd) != 0)
65 die("unable to write rerere record");
66 return commit_lock_file(&write_lock);
67}
68struct buffer {
70 char *ptr;
71 int nr, alloc;
72};
73static void append_line(struct buffer *buffer, const char *line)
75{
76 int len = strlen(line);
77 if (buffer->nr + len > buffer->alloc) {
79 buffer->alloc = alloc_nr(buffer->nr + len);
80 buffer->ptr = xrealloc(buffer->ptr, buffer->alloc);
81 }
82 memcpy(buffer->ptr + buffer->nr, line, len);
83 buffer->nr += len;
84}
85static void clear_buffer(struct buffer *buffer)
87{
88 free(buffer->ptr);
89 buffer->ptr = NULL;
90 buffer->nr = buffer->alloc = 0;
91}
92static int handle_file(const char *path,
94 unsigned char *sha1, const char *output)
95{
96 SHA_CTX ctx;
97 char buf[1024];
98 int hunk = 0, hunk_no = 0;
99 struct buffer minus = { NULL, 0, 0 }, plus = { NULL, 0, 0 };
100 struct buffer *one = &minus, *two = +
101 FILE *f = fopen(path, "r");
102 FILE *out;
103 if (!f)
105 return error("Could not open %s", path);
106 if (output) {
108 out = fopen(output, "w");
109 if (!out) {
110 fclose(f);
111 return error("Could not write %s", output);
112 }
113 } else
114 out = NULL;
115 if (sha1)
117 SHA1_Init(&ctx);
118 while (fgets(buf, sizeof(buf), f)) {
120 if (!prefixcmp(buf, "<<<<<<< "))
121 hunk = 1;
122 else if (!prefixcmp(buf, "======="))
123 hunk = 2;
124 else if (!prefixcmp(buf, ">>>>>>> ")) {
125 int one_is_longer = (one->nr > two->nr);
126 int common_len = one_is_longer ? two->nr : one->nr;
127 int cmp = memcmp(one->ptr, two->ptr, common_len);
128 hunk_no++;
130 hunk = 0;
131 if ((cmp > 0) || ((cmp == 0) && one_is_longer)) {
132 struct buffer *swap = one;
133 one = two;
134 two = swap;
135 }
136 if (out) {
137 fputs("<<<<<<<\n", out);
138 fwrite(one->ptr, one->nr, 1, out);
139 fputs("=======\n", out);
140 fwrite(two->ptr, two->nr, 1, out);
141 fputs(">>>>>>>\n", out);
142 }
143 if (sha1) {
144 SHA1_Update(&ctx, one->ptr, one->nr);
145 SHA1_Update(&ctx, "\0", 1);
146 SHA1_Update(&ctx, two->ptr, two->nr);
147 SHA1_Update(&ctx, "\0", 1);
148 }
149 clear_buffer(one);
150 clear_buffer(two);
151 } else if (hunk == 1)
152 append_line(one, buf);
153 else if (hunk == 2)
154 append_line(two, buf);
155 else if (out)
156 fputs(buf, out);
157 }
158 fclose(f);
160 if (out)
161 fclose(out);
162 if (sha1)
163 SHA1_Final(sha1, &ctx);
164 return hunk_no;
165}
166static int find_conflict(struct path_list *conflict)
168{
169 int i;
170 if (read_cache() < 0)
171 return error("Could not read index");
172 for (i = 0; i+1 < active_nr; i++) {
173 struct cache_entry *e2 = active_cache[i];
174 struct cache_entry *e3 = active_cache[i+1];
175 if (ce_stage(e2) == 2 &&
176 ce_stage(e3) == 3 &&
177 ce_same_name(e2, e3) &&
178 S_ISREG(ntohl(e2->ce_mode)) &&
179 S_ISREG(ntohl(e3->ce_mode))) {
180 path_list_insert((const char *)e2->name, conflict);
181 i++; /* skip over both #2 and #3 */
182 }
183 }
184 return 0;
185}
186static int merge(const char *name, const char *path)
188{
189 int ret;
190 mmfile_t cur, base, other;
191 mmbuffer_t result = {NULL, 0};
192 xpparam_t xpp = {XDF_NEED_MINIMAL};
193 if (handle_file(path, NULL, rr_path(name, "thisimage")) < 0)
195 return 1;
196 if (read_mmfile(&cur, rr_path(name, "thisimage")) ||
198 read_mmfile(&base, rr_path(name, "preimage")) ||
199 read_mmfile(&other, rr_path(name, "postimage")))
200 return 1;
201 ret = xdl_merge(&base, &cur, "", &other, "",
202 &xpp, XDL_MERGE_ZEALOUS, &result);
203 if (!ret) {
204 FILE *f = fopen(path, "w");
205 if (!f)
206 return error("Could not write to %s", path);
207 fwrite(result.ptr, result.size, 1, f);
208 fclose(f);
209 }
210 free(cur.ptr);
212 free(base.ptr);
213 free(other.ptr);
214 free(result.ptr);
215 return ret;
217}
218static void unlink_rr_item(const char *name)
220{
221 unlink(rr_path(name, "thisimage"));
222 unlink(rr_path(name, "preimage"));
223 unlink(rr_path(name, "postimage"));
224 rmdir(git_path("rr-cache/%s", name));
225}
226static void garbage_collect(struct path_list *rr)
228{
229 struct path_list to_remove = { NULL, 0, 0, 1 };
230 char buf[1024];
231 DIR *dir;
232 struct dirent *e;
233 int len, i, cutoff;
234 time_t now = time(NULL), then;
235 strlcpy(buf, git_path("rr-cache"), sizeof(buf));
237 len = strlen(buf);
238 dir = opendir(buf);
239 strcpy(buf + len++, "/");
240 while ((e = readdir(dir))) {
241 const char *name = e->d_name;
242 struct stat st;
243 if (name[0] == '.' && (name[1] == '\0' ||
244 (name[1] == '.' && name[2] == '\0')))
245 continue;
246 i = snprintf(buf + len, sizeof(buf) - len, "%s", name);
247 strlcpy(buf + len + i, "/preimage", sizeof(buf) - len - i);
248 if (stat(buf, &st))
249 continue;
250 then = st.st_mtime;
251 strlcpy(buf + len + i, "/postimage", sizeof(buf) - len - i);
252 cutoff = stat(buf, &st) ? cutoff_noresolve : cutoff_resolve;
253 if (then < now - cutoff * 86400) {
254 buf[len + i] = '\0';
255 path_list_insert(xstrdup(name), &to_remove);
256 }
257 }
258 for (i = 0; i < to_remove.nr; i++)
259 unlink_rr_item(to_remove.items[i].path);
260 path_list_clear(&to_remove, 0);
261}
262static int outf(void *dummy, mmbuffer_t *ptr, int nbuf)
264{
265 int i;
266 for (i = 0; i < nbuf; i++)
267 if (write_in_full(1, ptr[i].ptr, ptr[i].size) != ptr[i].size)
268 return -1;
269 return 0;
270}
271static int diff_two(const char *file1, const char *label1,
273 const char *file2, const char *label2)
274{
275 xpparam_t xpp;
276 xdemitconf_t xecfg;
277 xdemitcb_t ecb;
278 mmfile_t minus, plus;
279 if (read_mmfile(&minus, file1) || read_mmfile(&plus, file2))
281 return 1;
282 printf("--- a/%s\n+++ b/%s\n", label1, label2);
284 fflush(stdout);
285 xpp.flags = XDF_NEED_MINIMAL;
286 memset(&xecfg, 0, sizeof(xecfg));
287 xecfg.ctxlen = 3;
288 ecb.outf = outf;
289 xdl_diff(&minus, &plus, &xpp, &xecfg, &ecb);
290 free(minus.ptr);
292 free(plus.ptr);
293 return 0;
294}
295static int copy_file(const char *src, const char *dest)
297{
298 FILE *in, *out;
299 char buffer[32768];
300 int count;
301 if (!(in = fopen(src, "r")))
303 return error("Could not open %s", src);
304 if (!(out = fopen(dest, "w")))
305 return error("Could not open %s", dest);
306 while ((count = fread(buffer, 1, sizeof(buffer), in)))
307 fwrite(buffer, 1, count, out);
308 fclose(in);
309 fclose(out);
310 return 0;
311}
312static int do_plain_rerere(struct path_list *rr, int fd)
314{
315 struct path_list conflict = { NULL, 0, 0, 1 };
316 int i;
317 find_conflict(&conflict);
319 /*
321 * MERGE_RR records paths with conflicts immediately after merge
322 * failed. Some of the conflicted paths might have been hand resolved
323 * in the working tree since then, but the initial run would catch all
324 * and register their preimages.
325 */
326 for (i = 0; i < conflict.nr; i++) {
328 const char *path = conflict.items[i].path;
329 if (!path_list_has_path(rr, path)) {
330 unsigned char sha1[20];
331 char *hex;
332 int ret;
333 ret = handle_file(path, sha1, NULL);
334 if (ret < 1)
335 continue;
336 hex = xstrdup(sha1_to_hex(sha1));
337 path_list_insert(path, rr)->util = hex;
338 if (mkdir(git_path("rr-cache/%s", hex), 0755))
339 continue;;
340 handle_file(path, NULL, rr_path(hex, "preimage"));
341 fprintf(stderr, "Recorded preimage for '%s'\n", path);
342 }
343 }
344 /*
346 * Now some of the paths that had conflicts earlier might have been
347 * hand resolved. Others may be similar to a conflict already that
348 * was resolved before.
349 */
350 for (i = 0; i < rr->nr; i++) {
352 struct stat st;
353 int ret;
354 const char *path = rr->items[i].path;
355 const char *name = (const char *)rr->items[i].util;
356 if (!stat(rr_path(name, "preimage"), &st) &&
358 !stat(rr_path(name, "postimage"), &st)) {
359 if (!merge(name, path)) {
360 fprintf(stderr, "Resolved '%s' using "
361 "previous resolution.\n", path);
362 goto tail_optimization;
363 }
364 }
365 /* Let's see if we have resolved it. */
367 ret = handle_file(path, NULL, NULL);
368 if (ret)
369 continue;
370 fprintf(stderr, "Recorded resolution for '%s'.\n", path);
372 copy_file(path, rr_path(name, "postimage"));
373tail_optimization:
374 if (i < rr->nr - 1)
375 memmove(rr->items + i,
376 rr->items + i + 1,
377 sizeof(rr->items[0]) * (rr->nr - i - 1));
378 rr->nr--;
379 i--;
380 }
381 return write_rr(rr, fd);
383}
384static int git_rerere_config(const char *var, const char *value)
386{
387 if (!strcmp(var, "gc.rerereresolved"))
388 cutoff_resolve = git_config_int(var, value);
389 else if (!strcmp(var, "gc.rerereunresolved"))
390 cutoff_noresolve = git_config_int(var, value);
391 else if (!strcmp(var, "rerere.enabled"))
392 rerere_enabled = git_config_bool(var, value);
393 else
394 return git_default_config(var, value);
395 return 0;
396}
397static int is_rerere_enabled(void)
399{
400 struct stat st;
401 const char *rr_cache;
402 int rr_cache_exists;
403 if (!rerere_enabled)
405 return 0;
406 rr_cache = git_path("rr-cache");
408 rr_cache_exists = !stat(rr_cache, &st) && S_ISDIR(st.st_mode);
409 if (rerere_enabled < 0)
410 return rr_cache_exists;
411 if (!rr_cache_exists &&
413 (mkdir(rr_cache, 0777) || adjust_shared_perm(rr_cache)))
414 die("Could not create directory %s", rr_cache);
415 return 1;
416}
417int cmd_rerere(int argc, const char **argv, const char *prefix)
419{
420 struct path_list merge_rr = { NULL, 0, 0, 1 };
421 int i, fd = -1;
422 git_config(git_rerere_config);
424 if (!is_rerere_enabled())
425 return 0;
426 merge_rr_path = xstrdup(git_path("rr-cache/MERGE_RR"));
428 fd = hold_lock_file_for_update(&write_lock, merge_rr_path, 1);
429 read_rr(&merge_rr);
430 if (argc < 2)
432 return do_plain_rerere(&merge_rr, fd);
433 else if (!strcmp(argv[1], "clear")) {
434 for (i = 0; i < merge_rr.nr; i++) {
435 struct stat st;
436 const char *name = (const char *)merge_rr.items[i].util;
437 if (!stat(git_path("rr-cache/%s", name), &st) &&
438 S_ISDIR(st.st_mode) &&
439 stat(rr_path(name, "postimage"), &st))
440 unlink_rr_item(name);
441 }
442 unlink(merge_rr_path);
443 } else if (!strcmp(argv[1], "gc"))
444 garbage_collect(&merge_rr);
445 else if (!strcmp(argv[1], "status"))
446 for (i = 0; i < merge_rr.nr; i++)
447 printf("%s\n", merge_rr.items[i].path);
448 else if (!strcmp(argv[1], "diff"))
449 for (i = 0; i < merge_rr.nr; i++) {
450 const char *path = merge_rr.items[i].path;
451 const char *name = (const char *)merge_rr.items[i].util;
452 diff_two(rr_path(name, "preimage"), path, path, path);
453 }
454 else
455 usage(git_rerere_usage);
456 path_list_clear(&merge_rr, 1);
458 return 0;
459}