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