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 && ce_stage(e2) == 2 &&
 160                                 ce_stage(e3) == 3 && ce_same_name(e1, e2) &&
 161                                 ce_same_name(e1, e3)) {
 162                         path_list_insert((const char *)e1->name, conflict);
 163                         i += 3;
 164                 }
 165         }
 166         return 0;
 167 }
 168
 169 static int merge(const char *name, const char *path)
 170 {
 171         int ret;
 172         mmfile_t cur, base, other;
 173         mmbuffer_t result = {NULL, 0};
 174         xpparam_t xpp = {XDF_NEED_MINIMAL};
 175
 176         if (handle_file(path, NULL, rr_path(name, "thisimage")) < 0)
 177                 return 1;
 178
 179         if (read_mmfile(&cur, rr_path(name, "thisimage")) ||
 180                         read_mmfile(&base, rr_path(name, "preimage")) ||
 181                         read_mmfile(&other, rr_path(name, "postimage")))
 182                 return 1;
 183         ret = xdl_merge(&base, &cur, "", &other, "",
 184                         &xpp, XDL_MERGE_ZEALOUS, &result);
 185         if (!ret) {
 186                 FILE *f = fopen(path, "w");
 187                 if (!f)
 188                         return error("Could not write to %s", path);
 189                 fwrite(result.ptr, result.size, 1, f);
 190                 fclose(f);
 191         }
 192
 193         free(cur.ptr);
 194         free(base.ptr);
 195         free(other.ptr);
 196         free(result.ptr);
 197
 198         return ret;
 199 }
 200
 201 static void unlink_rr_item(const char *name)
 202 {
 203         unlink(rr_path(name, "thisimage"));
 204         unlink(rr_path(name, "preimage"));
 205         unlink(rr_path(name, "postimage"));
 206         rmdir(git_path("rr-cache/%s", name));
 207 }
 208
 209 static void garbage_collect(struct path_list *rr)
 210 {
 211         struct path_list to_remove = { NULL, 0, 0, 1 };
 212         char buf[1024];
 213         DIR *dir;
 214         struct dirent *e;
 215         int len, i, cutoff;
 216         time_t now = time(NULL), then;
 217
 218         strlcpy(buf, git_path("rr-cache"), sizeof(buf));
 219         len = strlen(buf);
 220         dir = opendir(buf);
 221         strcpy(buf + len++, "/");
 222         while ((e = readdir(dir))) {
 223                 const char *name = e->d_name;
 224                 struct stat st;
 225                 if (name[0] == '.' && (name[1] == '\0' ||
 226                                         (name[1] == '.' && name[2] == '\0')))
 227                         continue;
 228                 i = snprintf(buf + len, sizeof(buf) - len, "%s", name);
 229                 strlcpy(buf + len + i, "/preimage", sizeof(buf) - len - i);
 230                 if (stat(buf, &st))
 231                         continue;
 232                 then = st.st_mtime;
 233                 strlcpy(buf + len + i, "/postimage", sizeof(buf) - len - i);
 234                 cutoff = stat(buf, &st) ? cutoff_noresolve : cutoff_resolve;
 235                 if (then < now - cutoff * 86400) {
 236                         buf[len + i] = '\0';
 237                         path_list_insert(xstrdup(name), &to_remove);
 238                 }
 239         }
 240         for (i = 0; i < to_remove.nr; i++)
 241                 unlink_rr_item(to_remove.items[i].path);
 242         path_list_clear(&to_remove, 0);
 243 }
 244
 245 static int outf(void *dummy, mmbuffer_t *ptr, int nbuf)
 246 {
 247         int i;
 248         for (i = 0; i < nbuf; i++)
 249                 if (write_in_full(1, ptr[i].ptr, ptr[i].size) != ptr[i].size)
 250                         return -1;
 251         return 0;
 252 }
 253
 254 static int diff_two(const char *file1, const char *label1,
 255                 const char *file2, const char *label2)
 256 {
 257         xpparam_t xpp;
 258         xdemitconf_t xecfg;
 259         xdemitcb_t ecb;
 260         mmfile_t minus, plus;
 261
 262         if (read_mmfile(&minus, file1) || read_mmfile(&plus, file2))
 263                 return 1;
 264
 265         printf("--- a/%s\n+++ b/%s\n", label1, label2);
 266         fflush(stdout);
 267         xpp.flags = XDF_NEED_MINIMAL;
 268         xecfg.ctxlen = 3;
 269         xecfg.flags = 0;
 270         ecb.outf = outf;
 271         xdl_diff(&minus, &plus, &xpp, &xecfg, &ecb);
 272
 273         free(minus.ptr);
 274         free(plus.ptr);
 275         return 0;
 276 }
 277
 278 static int copy_file(const char *src, const char *dest)
 279 {
 280         FILE *in, *out;
 281         char buffer[32768];
 282         int count;
 283
 284         if (!(in = fopen(src, "r")))
 285                 return error("Could not open %s", src);
 286         if (!(out = fopen(dest, "w")))
 287                 return error("Could not open %s", dest);
 288         while ((count = fread(buffer, 1, sizeof(buffer), in)))
 289                 fwrite(buffer, 1, count, out);
 290         fclose(in);
 291         fclose(out);
 292         return 0;
 293 }
 294
 295 static int do_plain_rerere(struct path_list *rr, int fd)
 296 {
 297         struct path_list conflict = { NULL, 0, 0, 1 };
 298         int i;
 299
 300         find_conflict(&conflict);
 301
 302         /*
 303          * MERGE_RR records paths with conflicts immediately after merge
 304          * failed.  Some of the conflicted paths might have been hand resolved
 305          * in the working tree since then, but the initial run would catch all
 306          * and register their preimages.
 307          */
 308
 309         for (i = 0; i < conflict.nr; i++) {
 310                 const char *path = conflict.items[i].path;
 311                 if (!path_list_has_path(rr, path)) {
 312                         unsigned char sha1[20];
 313                         char *hex;
 314                         int ret;
 315                         ret = handle_file(path, sha1, NULL);
 316                         if (ret < 1)
 317                                 continue;
 318                         hex = xstrdup(sha1_to_hex(sha1));
 319                         path_list_insert(path, rr)->util = hex;
 320                         if (mkdir(git_path("rr-cache/%s", hex), 0755))
 321                                 continue;;
 322                         handle_file(path, NULL, rr_path(hex, "preimage"));
 323                         fprintf(stderr, "Recorded preimage for '%s'\n", path);
 324                 }
 325         }
 326
 327         /*
 328          * Now some of the paths that had conflicts earlier might have been
 329          * hand resolved.  Others may be similar to a conflict already that
 330          * was resolved before.
 331          */
 332
 333         for (i = 0; i < rr->nr; i++) {
 334                 struct stat st;
 335                 int ret;
 336                 const char *path = rr->items[i].path;
 337                 const char *name = (const char *)rr->items[i].util;
 338
 339                 if (!stat(rr_path(name, "preimage"), &st) &&
 340                                 !stat(rr_path(name, "postimage"), &st)) {
 341                         if (!merge(name, path)) {
 342                                 fprintf(stderr, "Resolved '%s' using "
 343                                                 "previous resolution.\n", path);
 344                                 goto tail_optimization;
 345                         }
 346                 }
 347
 348                 /* Let's see if we have resolved it. */
 349                 ret = handle_file(path, NULL, NULL);
 350                 if (ret)
 351                         continue;
 352
 353                 fprintf(stderr, "Recorded resolution for '%s'.\n", path);
 354                 copy_file(path, rr_path(name, "postimage"));
 355 tail_optimization:
 356                 if (i < rr->nr - 1)
 357                         memmove(rr->items + i,
 358                                 rr->items + i + 1,
 359                                 sizeof(rr->items[0]) * (rr->nr - i - 1));
 360                 rr->nr--;
 361                 i--;
 362         }
 363
 364         return write_rr(rr, fd);
 365 }
 366
 367 static int git_rerere_config(const char *var, const char *value)
 368 {
 369         if (!strcmp(var, "gc.rerereresolved"))
 370                 cutoff_resolve = git_config_int(var, value);
 371         else if (!strcmp(var, "gc.rerereunresolved"))
 372                 cutoff_noresolve = git_config_int(var, value);
 373         else
 374                 return git_default_config(var, value);
 375         return 0;
 376 }
 377
 378 int cmd_rerere(int argc, const char **argv, const char *prefix)
 379 {
 380         struct path_list merge_rr = { NULL, 0, 0, 1 };
 381         int i, fd = -1;
 382         struct stat st;
 383
 384         if (stat(git_path("rr-cache"), &st) || !S_ISDIR(st.st_mode))
 385                 return 0;
 386
 387         git_config(git_rerere_config);
 388
 389         merge_rr_path = xstrdup(git_path("rr-cache/MERGE_RR"));
 390         fd = hold_lock_file_for_update(&write_lock, merge_rr_path, 1);
 391         read_rr(&merge_rr);
 392
 393         if (argc < 2)
 394                 return do_plain_rerere(&merge_rr, fd);
 395         else if (!strcmp(argv[1], "clear")) {
 396                 for (i = 0; i < merge_rr.nr; i++) {
 397                         const char *name = (const char *)merge_rr.items[i].util;
 398                         if (!stat(git_path("rr-cache/%s", name), &st) &&
 399                                         S_ISDIR(st.st_mode) &&
 400                                         stat(rr_path(name, "postimage"), &st))
 401                                 unlink_rr_item(name);
 402                 }
 403                 unlink(merge_rr_path);
 404         } else if (!strcmp(argv[1], "gc"))
 405                 garbage_collect(&merge_rr);
 406         else if (!strcmp(argv[1], "status"))
 407                 for (i = 0; i < merge_rr.nr; i++)
 408                         printf("%s\n", merge_rr.items[i].path);
 409         else if (!strcmp(argv[1], "diff"))
 410                 for (i = 0; i < merge_rr.nr; i++) {
 411                         const char *path = merge_rr.items[i].path;
 412                         const char *name = (const char *)merge_rr.items[i].util;
 413                         diff_two(rr_path(name, "preimage"), path, path, path);
 414                 }
 415         else
 416                 usage(git_rerere_usage);
 417
 418         path_list_clear(&merge_rr, 1);
 419         return 0;
 420 }
 421