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                 write(out_fd, rr->items[i].util, 40);
  55                 write(out_fd, "\t", 1);
  56                 write(out_fd, path, strlen(path) + 1);
  57         }
  58         close(out_fd);
  59         return commit_lock_file(&write_lock);
  60 }
  61
  62 struct buffer {
  63         char *ptr;
  64         int nr, alloc;
  65 };
  66
  67 static void append_line(struct buffer *buffer, const char *line)
  68 {
  69         int len = strlen(line);
  70
  71         if (buffer->nr + len > buffer->alloc) {
  72                 buffer->alloc = alloc_nr(buffer->nr + len);
  73                 buffer->ptr = xrealloc(buffer->ptr, buffer->alloc);
  74         }
  75         memcpy(buffer->ptr + buffer->nr, line, len);
  76         buffer->nr += len;
  77 }
  78
  79 static int handle_file(const char *path,
  80          unsigned char *sha1, const char *output)
  81 {
  82         SHA_CTX ctx;
  83         char buf[1024];
  84         int hunk = 0, hunk_no = 0;
  85         struct buffer minus = { NULL, 0, 0 }, plus = { NULL, 0, 0 };
  86         struct buffer *one = &minus, *two = &plus;
  87         FILE *f = fopen(path, "r");
  88         FILE *out;
  89
  90         if (!f)
  91                 return error("Could not open %s", path);
  92
  93         if (output) {
  94                 out = fopen(output, "w");
  95                 if (!out) {
  96                         fclose(f);
  97                         return error("Could not write %s", output);
  98                 }
  99         } else
 100                 out = NULL;
 101
 102         if (sha1)
 103                 SHA1_Init(&ctx);
 104
 105         while (fgets(buf, sizeof(buf), f)) {
 106                 if (!strncmp("<<<<<<< ", buf, 8))
 107                         hunk = 1;
 108                 else if (!strncmp("=======", buf, 7))
 109                         hunk = 2;
 110                 else if (!strncmp(">>>>>>> ", buf, 8)) {
 111                         hunk_no++;
 112                         hunk = 0;
 113                         if (memcmp(one->ptr, two->ptr, one->nr < two->nr ?
 114                                                 one->nr : two->nr) > 0) {
 115                                 struct buffer *swap = one;
 116                                 one = two;
 117                                 two = swap;
 118                         }
 119                         if (out) {
 120                                 fputs("<<<<<<<\n", out);
 121                                 fwrite(one->ptr, one->nr, 1, out);
 122                                 fputs("=======\n", out);
 123                                 fwrite(two->ptr, two->nr, 1, out);
 124                                 fputs(">>>>>>>\n", out);
 125                         }
 126                         if (sha1) {
 127                                 SHA1_Update(&ctx, one->ptr, one->nr);
 128                                 SHA1_Update(&ctx, "\0", 1);
 129                                 SHA1_Update(&ctx, two->ptr, two->nr);
 130                                 SHA1_Update(&ctx, "\0", 1);
 131                         }
 132                 } else if (hunk == 1)
 133                         append_line(one, buf);
 134                 else if (hunk == 2)
 135                         append_line(two, buf);
 136                 else if (out)
 137                         fputs(buf, out);
 138         }
 139
 140         fclose(f);
 141         if (out)
 142                 fclose(out);
 143         if (sha1)
 144                 SHA1_Final(sha1, &ctx);
 145         return hunk_no;
 146 }
 147
 148 static int find_conflict(struct path_list *conflict)
 149 {
 150         int i;
 151         if (read_cache() < 0)
 152                 return error("Could not read index");
 153         for (i = 0; i + 2 < active_nr; i++) {
 154                 struct cache_entry *e1 = active_cache[i];
 155                 struct cache_entry *e2 = active_cache[i + 1];
 156                 struct cache_entry *e3 = active_cache[i + 2];
 157                 if (ce_stage(e1) == 1 && ce_stage(e2) == 2 &&
 158                                 ce_stage(e3) == 3 && ce_same_name(e1, e2) &&
 159                                 ce_same_name(e1, e3)) {
 160                         path_list_insert((const char *)e1->name, conflict);
 161                         i += 3;
 162                 }
 163         }
 164         return 0;
 165 }
 166
 167 static int merge(const char *name, const char *path)
 168 {
 169         int ret;
 170         mmfile_t cur, base, other;
 171         mmbuffer_t result = {NULL, 0};
 172         xpparam_t xpp = {XDF_NEED_MINIMAL};
 173
 174         if (handle_file(path, NULL, rr_path(name, "thisimage")) < 0)
 175                 return 1;
 176
 177         if (read_mmfile(&cur, rr_path(name, "thisimage")) ||
 178                         read_mmfile(&base, rr_path(name, "preimage")) ||
 179                         read_mmfile(&other, rr_path(name, "postimage")))
 180                 return 1;
 181         ret = xdl_merge(&base, &cur, "", &other, "",
 182                         &xpp, XDL_MERGE_ZEALOUS, &result);
 183         if (!ret) {
 184                 FILE *f = fopen(path, "w");
 185                 if (!f)
 186                         return error("Could not write to %s", path);
 187                 fwrite(result.ptr, result.size, 1, f);
 188                 fclose(f);
 189         }
 190
 191         free(cur.ptr);
 192         free(base.ptr);
 193         free(other.ptr);
 194         free(result.ptr);
 195
 196         return ret;
 197 }
 198
 199 static void unlink_rr_item(const char *name)
 200 {
 201         unlink(rr_path(name, "thisimage"));
 202         unlink(rr_path(name, "preimage"));
 203         unlink(rr_path(name, "postimage"));
 204         rmdir(git_path("rr-cache/%s", name));
 205 }
 206
 207 static void garbage_collect(struct path_list *rr)
 208 {
 209         struct path_list to_remove = { NULL, 0, 0, 1 };
 210         char buf[1024];
 211         DIR *dir;
 212         struct dirent *e;
 213         int len, i, cutoff;
 214         time_t now = time(NULL), then;
 215
 216         strlcpy(buf, git_path("rr-cache"), sizeof(buf));
 217         len = strlen(buf);
 218         dir = opendir(buf);
 219         strcpy(buf + len++, "/");
 220         while ((e = readdir(dir))) {
 221                 const char *name = e->d_name;
 222                 struct stat st;
 223                 if (name[0] == '.' && (name[1] == '\0' ||
 224                                         (name[1] == '.' && name[2] == '\0')))
 225                         continue;
 226                 i = snprintf(buf + len, sizeof(buf) - len, "%s", name);
 227                 strlcpy(buf + len + i, "/preimage", sizeof(buf) - len - i);
 228                 if (stat(buf, &st))
 229                         continue;
 230                 then = st.st_mtime;
 231                 strlcpy(buf + len + i, "/postimage", sizeof(buf) - len - i);
 232                 cutoff = stat(buf, &st) ? cutoff_noresolve : cutoff_resolve;
 233                 if (then < now - cutoff * 86400) {
 234                         buf[len + i] = '\0';
 235                         path_list_insert(xstrdup(name), &to_remove);
 236                 }
 237         }
 238         for (i = 0; i < to_remove.nr; i++)
 239                 unlink_rr_item(to_remove.items[i].path);
 240         path_list_clear(&to_remove, 0);
 241 }
 242
 243 static int outf(void *dummy, mmbuffer_t *ptr, int nbuf)
 244 {
 245         int i;
 246         for (i = 0; i < nbuf; i++)
 247                 write(1, ptr[i].ptr, ptr[i].size);
 248         return 0;
 249 }
 250
 251 static int diff_two(const char *file1, const char *label1,
 252                 const char *file2, const char *label2)
 253 {
 254         xpparam_t xpp;
 255         xdemitconf_t xecfg;
 256         xdemitcb_t ecb;
 257         mmfile_t minus, plus;
 258
 259         if (read_mmfile(&minus, file1) || read_mmfile(&plus, file2))
 260                 return 1;
 261
 262         printf("--- a/%s\n+++ b/%s\n", label1, label2);
 263         fflush(stdout);
 264         xpp.flags = XDF_NEED_MINIMAL;
 265         xecfg.ctxlen = 3;
 266         xecfg.flags = 0;
 267         ecb.outf = outf;
 268         xdl_diff(&minus, &plus, &xpp, &xecfg, &ecb);
 269
 270         free(minus.ptr);
 271         free(plus.ptr);
 272         return 0;
 273 }
 274
 275 static int copy_file(const char *src, const char *dest)
 276 {
 277         FILE *in, *out;
 278         char buffer[32768];
 279         int count;
 280
 281         if (!(in = fopen(src, "r")))
 282                 return error("Could not open %s", src);
 283         if (!(out = fopen(dest, "w")))
 284                 return error("Could not open %s", dest);
 285         while ((count = fread(buffer, 1, sizeof(buffer), in)))
 286                 fwrite(buffer, 1, count, out);
 287         fclose(in);
 288         fclose(out);
 289         return 0;
 290 }
 291
 292 static int do_plain_rerere(struct path_list *rr, int fd)
 293 {
 294         struct path_list conflict = { NULL, 0, 0, 1 };
 295         int i;
 296
 297         find_conflict(&conflict);
 298
 299         /*
 300          * MERGE_RR records paths with conflicts immediately after merge
 301          * failed.  Some of the conflicted paths might have been hand resolved
 302          * in the working tree since then, but the initial run would catch all
 303          * and register their preimages.
 304          */
 305
 306         for (i = 0; i < conflict.nr; i++) {
 307                 const char *path = conflict.items[i].path;
 308                 if (!path_list_has_path(rr, path)) {
 309                         unsigned char sha1[20];
 310                         char *hex;
 311                         int ret;
 312                         ret = handle_file(path, sha1, NULL);
 313                         if (ret < 1)
 314                                 continue;
 315                         hex = xstrdup(sha1_to_hex(sha1));
 316                         path_list_insert(path, rr)->util = hex;
 317                         if (mkdir(git_path("rr-cache/%s", hex), 0755))
 318                                 continue;;
 319                         handle_file(path, NULL, rr_path(hex, "preimage"));
 320                         fprintf(stderr, "Recorded preimage for '%s'\n", path);
 321                 }
 322         }
 323
 324         /*
 325          * Now some of the paths that had conflicts earlier might have been
 326          * hand resolved.  Others may be similar to a conflict already that
 327          * was resolved before.
 328          */
 329
 330         for (i = 0; i < rr->nr; i++) {
 331                 struct stat st;
 332                 int ret;
 333                 const char *path = rr->items[i].path;
 334                 const char *name = (const char *)rr->items[i].util;
 335
 336                 if (!stat(rr_path(name, "preimage"), &st) &&
 337                                 !stat(rr_path(name, "postimage"), &st)) {
 338                         if (!merge(name, path)) {
 339                                 fprintf(stderr, "Resolved '%s' using "
 340                                                 "previous resolution.\n", path);
 341                                 goto tail_optimization;
 342                         }
 343                 }
 344
 345                 /* Let's see if we have resolved it. */
 346                 ret = handle_file(path, NULL, NULL);
 347                 if (ret)
 348                         continue;
 349
 350                 fprintf(stderr, "Recorded resolution for '%s'.\n", path);
 351                 copy_file(path, rr_path(name, "postimage"));
 352 tail_optimization:
 353                 if (i < rr->nr - 1) {
 354                         memmove(rr->items + i,
 355                                         rr->items + i + 1,
 356                                         rr->nr - i - 1);
 357                 }
 358                 rr->nr--;
 359                 i--;
 360         }
 361
 362         return write_rr(rr, fd);
 363 }
 364
 365 static int git_rerere_config(const char *var, const char *value)
 366 {
 367         if (!strcmp(var, "gc.rerereresolved"))
 368                 cutoff_resolve = git_config_int(var, value);
 369         else if (!strcmp(var, "gc.rerereunresolved"))
 370                 cutoff_noresolve = git_config_int(var, value);
 371         else
 372                 return git_default_config(var, value);
 373         return 0;
 374 }
 375
 376 int cmd_rerere(int argc, const char **argv, const char *prefix)
 377 {
 378         struct path_list merge_rr = { NULL, 0, 0, 1 };
 379         int i, fd = -1;
 380         struct stat st;
 381
 382         if (stat(git_path("rr-cache"), &st) || !S_ISDIR(st.st_mode))
 383                 return 0;
 384
 385         git_config(git_rerere_config);
 386
 387         merge_rr_path = xstrdup(git_path("rr-cache/MERGE_RR"));
 388         fd = hold_lock_file_for_update(&write_lock, merge_rr_path, 1);
 389         read_rr(&merge_rr);
 390
 391         if (argc < 2)
 392                 return do_plain_rerere(&merge_rr, fd);
 393         else if (!strcmp(argv[1], "clear")) {
 394                 for (i = 0; i < merge_rr.nr; i++) {
 395                         const char *name = (const char *)merge_rr.items[i].util;
 396                         if (!stat(git_path("rr-cache/%s", name), &st) &&
 397                                         S_ISDIR(st.st_mode) &&
 398                                         stat(rr_path(name, "postimage"), &st))
 399                                 unlink_rr_item(name);
 400                 }
 401                 unlink(merge_rr_path);
 402         } else if (!strcmp(argv[1], "gc"))
 403                 garbage_collect(&merge_rr);
 404         else if (!strcmp(argv[1], "status"))
 405                 for (i = 0; i < merge_rr.nr; i++)
 406                         printf("%s\n", merge_rr.items[i].path);
 407         else if (!strcmp(argv[1], "diff"))
 408                 for (i = 0; i < merge_rr.nr; i++) {
 409                         const char *path = merge_rr.items[i].path;
 410                         const char *name = (const char *)merge_rr.items[i].util;
 411                         diff_two(rr_path(name, "preimage"), path, path, path);
 412                 }
 413         else
 414                 usage(git_rerere_usage);
 415
 416         path_list_clear(&merge_rr, 1);
 417         return 0;
 418 }
 419