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 void clear_buffer(struct buffer *buffer)
  82 {
  83         free(buffer->ptr);
  84         buffer->ptr = NULL;
  85         buffer->nr = buffer->alloc = 0;
  86 }
  87
  88 static int handle_file(const char *path,
  89          unsigned char *sha1, const char *output)
  90 {
  91         SHA_CTX ctx;
  92         char buf[1024];
  93         int hunk = 0, hunk_no = 0;
  94         struct buffer minus = { NULL, 0, 0 }, plus = { NULL, 0, 0 };
  95         struct buffer *one = &minus, *two = &plus;
  96         FILE *f = fopen(path, "r");
  97         FILE *out;
  98
  99         if (!f)
 100                 return error("Could not open %s", path);
 101
 102         if (output) {
 103                 out = fopen(output, "w");
 104                 if (!out) {
 105                         fclose(f);
 106                         return error("Could not write %s", output);
 107                 }
 108         } else
 109                 out = NULL;
 110
 111         if (sha1)
 112                 SHA1_Init(&ctx);
 113
 114         while (fgets(buf, sizeof(buf), f)) {
 115                 if (!prefixcmp(buf, "<<<<<<< "))
 116                         hunk = 1;
 117                 else if (!prefixcmp(buf, "======="))
 118                         hunk = 2;
 119                 else if (!prefixcmp(buf, ">>>>>>> ")) {
 120                         int one_is_longer = (one->nr > two->nr);
 121                         int common_len = one_is_longer ? two->nr : one->nr;
 122                         int cmp = memcmp(one->ptr, two->ptr, common_len);
 123
 124                         hunk_no++;
 125                         hunk = 0;
 126                         if ((cmp > 0) || ((cmp == 0) && one_is_longer)) {
 127                                 struct buffer *swap = one;
 128                                 one = two;
 129                                 two = swap;
 130                         }
 131                         if (out) {
 132                                 fputs("<<<<<<<\n", out);
 133                                 fwrite(one->ptr, one->nr, 1, out);
 134                                 fputs("=======\n", out);
 135                                 fwrite(two->ptr, two->nr, 1, out);
 136                                 fputs(">>>>>>>\n", out);
 137                         }
 138                         if (sha1) {
 139                                 SHA1_Update(&ctx, one->ptr, one->nr);
 140                                 SHA1_Update(&ctx, "\0", 1);
 141                                 SHA1_Update(&ctx, two->ptr, two->nr);
 142                                 SHA1_Update(&ctx, "\0", 1);
 143                         }
 144                         clear_buffer(one);
 145                         clear_buffer(two);
 146                 } else if (hunk == 1)
 147                         append_line(one, buf);
 148                 else if (hunk == 2)
 149                         append_line(two, buf);
 150                 else if (out)
 151                         fputs(buf, out);
 152         }
 153
 154         fclose(f);
 155         if (out)
 156                 fclose(out);
 157         if (sha1)
 158                 SHA1_Final(sha1, &ctx);
 159         return hunk_no;
 160 }
 161
 162 static int find_conflict(struct path_list *conflict)
 163 {
 164         int i;
 165         if (read_cache() < 0)
 166                 return error("Could not read index");
 167         for (i = 0; i + 2 < active_nr; i++) {
 168                 struct cache_entry *e1 = active_cache[i];
 169                 struct cache_entry *e2 = active_cache[i+1];
 170                 struct cache_entry *e3 = active_cache[i+2];
 171                 if (ce_stage(e1) == 1 &&
 172                     ce_stage(e2) == 2 &&
 173                     ce_stage(e3) == 3 &&
 174                     ce_same_name(e1, e2) && ce_same_name(e1, e3) &&
 175                     S_ISREG(ntohl(e1->ce_mode)) &&
 176                     S_ISREG(ntohl(e2->ce_mode)) &&
 177                     S_ISREG(ntohl(e3->ce_mode))) {
 178                         path_list_insert((const char *)e1->name, conflict);
 179                         i += 2;
 180                 }
 181         }
 182         return 0;
 183 }
 184
 185 static int merge(const char *name, const char *path)
 186 {
 187         int ret;
 188         mmfile_t cur, base, other;
 189         mmbuffer_t result = {NULL, 0};
 190         xpparam_t xpp = {XDF_NEED_MINIMAL};
 191
 192         if (handle_file(path, NULL, rr_path(name, "thisimage")) < 0)
 193                 return 1;
 194
 195         if (read_mmfile(&cur, rr_path(name, "thisimage")) ||
 196                         read_mmfile(&base, rr_path(name, "preimage")) ||
 197                         read_mmfile(&other, rr_path(name, "postimage")))
 198                 return 1;
 199         ret = xdl_merge(&base, &cur, "", &other, "",
 200                         &xpp, XDL_MERGE_ZEALOUS, &result);
 201         if (!ret) {
 202                 FILE *f = fopen(path, "w");
 203                 if (!f)
 204                         return error("Could not write to %s", path);
 205                 fwrite(result.ptr, result.size, 1, f);
 206                 fclose(f);
 207         }
 208
 209         free(cur.ptr);
 210         free(base.ptr);
 211         free(other.ptr);
 212         free(result.ptr);
 213
 214         return ret;
 215 }
 216
 217 static void unlink_rr_item(const char *name)
 218 {
 219         unlink(rr_path(name, "thisimage"));
 220         unlink(rr_path(name, "preimage"));
 221         unlink(rr_path(name, "postimage"));
 222         rmdir(git_path("rr-cache/%s", name));
 223 }
 224
 225 static void garbage_collect(struct path_list *rr)
 226 {
 227         struct path_list to_remove = { NULL, 0, 0, 1 };
 228         char buf[1024];
 229         DIR *dir;
 230         struct dirent *e;
 231         int len, i, cutoff;
 232         time_t now = time(NULL), then;
 233
 234         strlcpy(buf, git_path("rr-cache"), sizeof(buf));
 235         len = strlen(buf);
 236         dir = opendir(buf);
 237         strcpy(buf + len++, "/");
 238         while ((e = readdir(dir))) {
 239                 const char *name = e->d_name;
 240                 struct stat st;
 241                 if (name[0] == '.' && (name[1] == '\0' ||
 242                                         (name[1] == '.' && name[2] == '\0')))
 243                         continue;
 244                 i = snprintf(buf + len, sizeof(buf) - len, "%s", name);
 245                 strlcpy(buf + len + i, "/preimage", sizeof(buf) - len - i);
 246                 if (stat(buf, &st))
 247                         continue;
 248                 then = st.st_mtime;
 249                 strlcpy(buf + len + i, "/postimage", sizeof(buf) - len - i);
 250                 cutoff = stat(buf, &st) ? cutoff_noresolve : cutoff_resolve;
 251                 if (then < now - cutoff * 86400) {
 252                         buf[len + i] = '\0';
 253                         path_list_insert(xstrdup(name), &to_remove);
 254                 }
 255         }
 256         for (i = 0; i < to_remove.nr; i++)
 257                 unlink_rr_item(to_remove.items[i].path);
 258         path_list_clear(&to_remove, 0);
 259 }
 260
 261 static int outf(void *dummy, mmbuffer_t *ptr, int nbuf)
 262 {
 263         int i;
 264         for (i = 0; i < nbuf; i++)
 265                 if (write_in_full(1, ptr[i].ptr, ptr[i].size) != ptr[i].size)
 266                         return -1;
 267         return 0;
 268 }
 269
 270 static int diff_two(const char *file1, const char *label1,
 271                 const char *file2, const char *label2)
 272 {
 273         xpparam_t xpp;
 274         xdemitconf_t xecfg;
 275         xdemitcb_t ecb;
 276         mmfile_t minus, plus;
 277
 278         if (read_mmfile(&minus, file1) || read_mmfile(&plus, file2))
 279                 return 1;
 280
 281         printf("--- a/%s\n+++ b/%s\n", label1, label2);
 282         fflush(stdout);
 283         xpp.flags = XDF_NEED_MINIMAL;
 284         xecfg.ctxlen = 3;
 285         xecfg.flags = 0;
 286         ecb.outf = outf;
 287         xdl_diff(&minus, &plus, &xpp, &xecfg, &ecb);
 288
 289         free(minus.ptr);
 290         free(plus.ptr);
 291         return 0;
 292 }
 293
 294 static int copy_file(const char *src, const char *dest)
 295 {
 296         FILE *in, *out;
 297         char buffer[32768];
 298         int count;
 299
 300         if (!(in = fopen(src, "r")))
 301                 return error("Could not open %s", src);
 302         if (!(out = fopen(dest, "w")))
 303                 return error("Could not open %s", dest);
 304         while ((count = fread(buffer, 1, sizeof(buffer), in)))
 305                 fwrite(buffer, 1, count, out);
 306         fclose(in);
 307         fclose(out);
 308         return 0;
 309 }
 310
 311 static int do_plain_rerere(struct path_list *rr, int fd)
 312 {
 313         struct path_list conflict = { NULL, 0, 0, 1 };
 314         int i;
 315
 316         find_conflict(&conflict);
 317
 318         /*
 319          * MERGE_RR records paths with conflicts immediately after merge
 320          * failed.  Some of the conflicted paths might have been hand resolved
 321          * in the working tree since then, but the initial run would catch all
 322          * and register their preimages.
 323          */
 324
 325         for (i = 0; i < conflict.nr; i++) {
 326                 const char *path = conflict.items[i].path;
 327                 if (!path_list_has_path(rr, path)) {
 328                         unsigned char sha1[20];
 329                         char *hex;
 330                         int ret;
 331                         ret = handle_file(path, sha1, NULL);
 332                         if (ret < 1)
 333                                 continue;
 334                         hex = xstrdup(sha1_to_hex(sha1));
 335                         path_list_insert(path, rr)->util = hex;
 336                         if (mkdir(git_path("rr-cache/%s", hex), 0755))
 337                                 continue;;
 338                         handle_file(path, NULL, rr_path(hex, "preimage"));
 339                         fprintf(stderr, "Recorded preimage for '%s'\n", path);
 340                 }
 341         }
 342
 343         /*
 344          * Now some of the paths that had conflicts earlier might have been
 345          * hand resolved.  Others may be similar to a conflict already that
 346          * was resolved before.
 347          */
 348
 349         for (i = 0; i < rr->nr; i++) {
 350                 struct stat st;
 351                 int ret;
 352                 const char *path = rr->items[i].path;
 353                 const char *name = (const char *)rr->items[i].util;
 354
 355                 if (!stat(rr_path(name, "preimage"), &st) &&
 356                                 !stat(rr_path(name, "postimage"), &st)) {
 357                         if (!merge(name, path)) {
 358                                 fprintf(stderr, "Resolved '%s' using "
 359                                                 "previous resolution.\n", path);
 360                                 goto tail_optimization;
 361                         }
 362                 }
 363
 364                 /* Let's see if we have resolved it. */
 365                 ret = handle_file(path, NULL, NULL);
 366                 if (ret)
 367                         continue;
 368
 369                 fprintf(stderr, "Recorded resolution for '%s'.\n", path);
 370                 copy_file(path, rr_path(name, "postimage"));
 371 tail_optimization:
 372                 if (i < rr->nr - 1)
 373                         memmove(rr->items + i,
 374                                 rr->items + i + 1,
 375                                 sizeof(rr->items[0]) * (rr->nr - i - 1));
 376                 rr->nr--;
 377                 i--;
 378         }
 379
 380         return write_rr(rr, fd);
 381 }
 382
 383 static int git_rerere_config(const char *var, const char *value)
 384 {
 385         if (!strcmp(var, "gc.rerereresolved"))
 386                 cutoff_resolve = git_config_int(var, value);
 387         else if (!strcmp(var, "gc.rerereunresolved"))
 388                 cutoff_noresolve = git_config_int(var, value);
 389         else
 390                 return git_default_config(var, value);
 391         return 0;
 392 }
 393
 394 int cmd_rerere(int argc, const char **argv, const char *prefix)
 395 {
 396         struct path_list merge_rr = { NULL, 0, 0, 1 };
 397         int i, fd = -1;
 398         struct stat st;
 399
 400         if (stat(git_path("rr-cache"), &st) || !S_ISDIR(st.st_mode))
 401                 return 0;
 402
 403         git_config(git_rerere_config);
 404
 405         merge_rr_path = xstrdup(git_path("rr-cache/MERGE_RR"));
 406         fd = hold_lock_file_for_update(&write_lock, merge_rr_path, 1);
 407         read_rr(&merge_rr);
 408
 409         if (argc < 2)
 410                 return do_plain_rerere(&merge_rr, fd);
 411         else if (!strcmp(argv[1], "clear")) {
 412                 for (i = 0; i < merge_rr.nr; i++) {
 413                         const char *name = (const char *)merge_rr.items[i].util;
 414                         if (!stat(git_path("rr-cache/%s", name), &st) &&
 415                                         S_ISDIR(st.st_mode) &&
 416                                         stat(rr_path(name, "postimage"), &st))
 417                                 unlink_rr_item(name);
 418                 }
 419                 unlink(merge_rr_path);
 420         } else if (!strcmp(argv[1], "gc"))
 421                 garbage_collect(&merge_rr);
 422         else if (!strcmp(argv[1], "status"))
 423                 for (i = 0; i < merge_rr.nr; i++)
 424                         printf("%s\n", merge_rr.items[i].path);
 425         else if (!strcmp(argv[1], "diff"))
 426                 for (i = 0; i < merge_rr.nr; i++) {
 427                         const char *path = merge_rr.items[i].path;
 428                         const char *name = (const char *)merge_rr.items[i].util;
 429                         diff_two(rr_path(name, "preimage"), path, path, path);
 430                 }
 431         else
 432                 usage(git_rerere_usage);
 433
 434         path_list_clear(&merge_rr, 1);
 435         return 0;
 436 }
 437