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