server-info.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "object.h"
   4 #include "commit.h"
   5 #include "tag.h"
   6
   7 /* refs */
   8 static FILE *info_ref_fp;
   9
  10 static int add_info_ref(const char *path, const unsigned char *sha1)
  11 {
  12         fprintf(info_ref_fp, "%s        %s\n", sha1_to_hex(sha1), path);
  13         return 0;
  14 }
  15
  16 static int update_info_refs(int force)
  17 {
  18         char *path0 = strdup(git_path("info/refs"));
  19         int len = strlen(path0);
  20         char *path1 = xmalloc(len + 2);
  21
  22         strcpy(path1, path0);
  23         strcpy(path1 + len, "+");
  24
  25         safe_create_leading_directories(path0);
  26         info_ref_fp = fopen(path1, "w");
  27         if (!info_ref_fp)
  28                 return error("unable to update %s", path0);
  29         for_each_ref(add_info_ref);
  30         fclose(info_ref_fp);
  31         rename(path1, path0);
  32         free(path0);
  33         free(path1);
  34         return 0;
  35 }
  36
  37 /* packs */
  38 static struct pack_info {
  39         unsigned long latest;
  40         struct packed_git *p;
  41         int old_num;
  42         int new_num;
  43         int nr_alloc;
  44         int nr_heads;
  45         unsigned char (*head)[20];
  46         char dep[0]; /* more */
  47 } **info;
  48 static int num_pack;
  49 static const char *objdir;
  50 static int objdirlen;
  51
  52 static struct object *parse_object_cheap(const unsigned char *sha1)
  53 {
  54         struct object *o;
  55
  56         if ((o = parse_object(sha1)) == NULL)
  57                 return NULL;
  58         if (o->type == commit_type) {
  59                 struct commit *commit = (struct commit *)o;
  60                 free(commit->buffer);
  61                 commit->buffer = NULL;
  62         }
  63         return o;
  64 }
  65
  66 static struct pack_info *find_pack_by_name(const char *name)
  67 {
  68         int i;
  69         for (i = 0; i < num_pack; i++) {
  70                 struct packed_git *p = info[i]->p;
  71                 /* skip "/pack/" after ".git/objects" */
  72                 if (!strcmp(p->pack_name + objdirlen + 6, name))
  73                         return info[i];
  74         }
  75         return NULL;
  76 }
  77
  78 static struct pack_info *find_pack_by_old_num(int old_num)
  79 {
  80         int i;
  81         for (i = 0; i < num_pack; i++)
  82                 if (info[i]->old_num == old_num)
  83                         return info[i];
  84         return NULL;
  85 }
  86
  87 static int add_head_def(struct pack_info *this, unsigned char *sha1)
  88 {
  89         if (this->nr_alloc <= this->nr_heads) {
  90                 this->nr_alloc = alloc_nr(this->nr_alloc);
  91                 this->head = xrealloc(this->head, this->nr_alloc * 20);
  92         }
  93         memcpy(this->head[this->nr_heads++], sha1, 20);
  94         return 0;
  95 }
  96
  97 /* Returns non-zero when we detect that the info in the
  98  * old file is useless.
  99  */
 100 static int parse_pack_def(const char *line, int old_cnt)
 101 {
 102         struct pack_info *i = find_pack_by_name(line + 2);
 103         if (i) {
 104                 i->old_num = old_cnt;
 105                 return 0;
 106         }
 107         else {
 108                 /* The file describes a pack that is no longer here;
 109                  * dependencies between packs needs to be recalculated.
 110                  */
 111                 return 1;
 112         }
 113 }
 114
 115 /* Returns non-zero when we detect that the info in the
 116  * old file is useless.
 117  */
 118 static int parse_depend_def(char *line)
 119 {
 120         unsigned long num;
 121         char *cp, *ep;
 122         struct pack_info *this, *that;
 123
 124         cp = line + 2;
 125         num = strtoul(cp, &ep, 10);
 126         if (ep == cp)
 127                 return error("invalid input %s", line);
 128         this = find_pack_by_old_num(num);
 129         if (!this)
 130                 return 0;
 131         while (ep && *(cp = ep)) {
 132                 num = strtoul(cp, &ep, 10);
 133                 if (ep == cp)
 134                         break;
 135                 that = find_pack_by_old_num(num);
 136                 if (!that)
 137                         /* The pack this one depends on does not
 138                          * exist; this should not happen because
 139                          * we write out the list of packs first and
 140                          * then dependency information, but it means
 141                          * the file is useless anyway.
 142                          */
 143                         return 1;
 144                 this->dep[that->new_num] = 1;
 145         }
 146         return 0;
 147 }
 148
 149 /* Returns non-zero when we detect that the info in the
 150  * old file is useless.
 151  */
 152 static int parse_head_def(char *line)
 153 {
 154         unsigned char sha1[20];
 155         unsigned long num;
 156         char *cp, *ep;
 157         struct pack_info *this;
 158         struct object *o;
 159
 160         cp = line + 2;
 161         num = strtoul(cp, &ep, 10);
 162         if (ep == cp || *ep++ != ' ')
 163                 return error("invalid input ix %s", line);
 164         this = find_pack_by_old_num(num);
 165         if (!this)
 166                 return 1; /* You know the drill. */
 167         if (get_sha1_hex(ep, sha1) || ep[40] != ' ')
 168                 return error("invalid input sha1 %s (%s)", line, ep);
 169         if ((o = parse_object_cheap(sha1)) == NULL)
 170                 return error("no such object: %s", line);
 171         return add_head_def(this, sha1);
 172 }
 173
 174 /* Returns non-zero when we detect that the info in the
 175  * old file is useless.
 176  */
 177 static int read_pack_info_file(const char *infofile)
 178 {
 179         FILE *fp;
 180         char line[1000];
 181         int old_cnt = 0;
 182
 183         fp = fopen(infofile, "r");
 184         if (!fp)
 185                 return 1; /* nonexisting is not an error. */
 186
 187         while (fgets(line, sizeof(line), fp)) {
 188                 int len = strlen(line);
 189                 if (line[len-1] == '\n')
 190                         line[len-1] = 0;
 191
 192                 switch (line[0]) {
 193                 case 'P': /* P name */
 194                         if (parse_pack_def(line, old_cnt++))
 195                                 goto out_stale;
 196                         break;
 197                 case 'D': /* D ix dep-ix1 dep-ix2... */
 198                         if (parse_depend_def(line))
 199                                 goto out_stale;
 200                         break;
 201                 case 'T': /* T ix sha1 type */
 202                         if (parse_head_def(line))
 203                                 goto out_stale;
 204                         break;
 205                 default:
 206                         error("unrecognized: %s", line);
 207                         break;
 208                 }
 209         }
 210         fclose(fp);
 211         return 0;
 212  out_stale:
 213         fclose(fp);
 214         return 1;
 215 }
 216
 217 /* We sort the packs according to the date of the latest commit.  That
 218  * in turn indicates how young the pack is, and in general we would
 219  * want to depend on younger packs.
 220  */
 221 static unsigned long get_latest_commit_date(struct packed_git *p)
 222 {
 223         unsigned char sha1[20];
 224         struct object *o;
 225         int num = num_packed_objects(p);
 226         int i;
 227         unsigned long latest = 0;
 228
 229         for (i = 0; i < num; i++) {
 230                 if (nth_packed_object_sha1(p, i, sha1))
 231                         die("corrupt pack file %s?", p->pack_name);
 232                 if ((o = parse_object_cheap(sha1)) == NULL)
 233                         die("cannot parse %s", sha1_to_hex(sha1));
 234                 if (o->type == commit_type) {
 235                         struct commit *commit = (struct commit *)o;
 236                         if (latest < commit->date)
 237                                 latest = commit->date;
 238                 }
 239         }
 240         return latest;
 241 }
 242
 243 static int compare_info(const void *a_, const void *b_)
 244 {
 245         struct pack_info * const* a = a_;
 246         struct pack_info * const* b = b_;
 247
 248         if (0 <= (*a)->old_num && 0 <= (*b)->old_num)
 249                 /* Keep the order in the original */
 250                 return (*a)->old_num - (*b)->old_num;
 251         else if (0 <= (*a)->old_num)
 252                 /* Only A existed in the original so B is obviously newer */
 253                 return -1;
 254         else if (0 <= (*b)->old_num)
 255                 /* The other way around. */
 256                 return 1;
 257
 258         if ((*a)->latest < (*b)->latest)
 259                 return -1;
 260         else if ((*a)->latest == (*b)->latest)
 261                 return 0;
 262         else
 263                 return 1;
 264 }
 265
 266 static void init_pack_info(const char *infofile, int force)
 267 {
 268         struct packed_git *p;
 269         int stale;
 270         int i = 0;
 271         char *dep_temp;
 272
 273         objdir = get_object_directory();
 274         objdirlen = strlen(objdir);
 275
 276         prepare_packed_git();
 277         for (p = packed_git; p; p = p->next) {
 278                 /* we ignore things on alternate path since they are
 279                  * not available to the pullers in general.
 280                  */
 281                 if (strncmp(p->pack_name, objdir, objdirlen) ||
 282                     strncmp(p->pack_name + objdirlen, "/pack/", 6))
 283                         continue;
 284                 i++;
 285         }
 286         num_pack = i;
 287         info = xcalloc(num_pack, sizeof(struct pack_info *));
 288         for (i = 0, p = packed_git; p; p = p->next) {
 289                 if (strncmp(p->pack_name, objdir, objdirlen) ||
 290                     p->pack_name[objdirlen] != '/')
 291                         continue;
 292                 info[i] = xcalloc(1, sizeof(struct pack_info) + num_pack);
 293                 info[i]->p = p;
 294                 info[i]->old_num = -1;
 295                 i++;
 296         }
 297
 298         if (infofile && !force)
 299                 stale = read_pack_info_file(infofile);
 300         else
 301                 stale = 1;
 302
 303         for (i = 0; i < num_pack; i++) {
 304                 if (stale) {
 305                         info[i]->old_num = -1;
 306                         memset(info[i]->dep, 0, num_pack);
 307                         info[i]->nr_heads = 0;
 308                 }
 309                 if (info[i]->old_num < 0)
 310                         info[i]->latest = get_latest_commit_date(info[i]->p);
 311         }
 312
 313         qsort(info, num_pack, sizeof(info[0]), compare_info);
 314         for (i = 0; i < num_pack; i++)
 315                 info[i]->new_num = i;
 316
 317         /* we need to fix up the dependency information
 318          * for the old ones.
 319          */
 320         dep_temp = NULL;
 321         for (i = 0; i < num_pack; i++) {
 322                 int old;
 323
 324                 if (info[i]->old_num < 0)
 325                         continue;
 326                 if (! dep_temp)
 327                         dep_temp = xmalloc(num_pack);
 328                 memset(dep_temp, 0, num_pack);
 329                 for (old = 0; old < num_pack; old++) {
 330                         struct pack_info *base;
 331                         if (!info[i]->dep[old])
 332                                 continue;
 333                         base = find_pack_by_old_num(old);
 334                         if (!base)
 335                                 die("internal error renumbering");
 336                         dep_temp[base->new_num] = 1;
 337                 }
 338                 memcpy(info[i]->dep, dep_temp, num_pack);
 339         }
 340         free(dep_temp);
 341 }
 342
 343 static void write_pack_info_file(FILE *fp)
 344 {
 345         int i, j;
 346         for (i = 0; i < num_pack; i++)
 347                 fprintf(fp, "P %s\n", info[i]->p->pack_name + objdirlen + 6);
 348
 349         for (i = 0; i < num_pack; i++) {
 350                 fprintf(fp, "D %1d", i);
 351                 for (j = 0; j < num_pack; j++) {
 352                         if ((i == j) || !(info[i]->dep[j]))
 353                                 continue;
 354                         fprintf(fp, " %1d", j);
 355                 }
 356                 fputc('\n', fp);
 357         }
 358
 359         for (i = 0; i < num_pack; i++) {
 360                 struct pack_info *this = info[i];
 361                 for (j = 0; j < this->nr_heads; j++) {
 362                         struct object *o = lookup_object(this->head[j]);
 363                         fprintf(fp, "T %1d %s %s\n",
 364                                 i, sha1_to_hex(this->head[j]), o->type);
 365                 }
 366         }
 367
 368 }
 369
 370 #define REFERENCED 01
 371 #define INTERNAL  02
 372 #define EMITTED   04
 373
 374 static void show(struct object *o, int pack_ix)
 375 {
 376         /*
 377          * We are interested in objects that are not referenced,
 378          * and objects that are referenced but not internal.
 379          */
 380         if (o->flags & EMITTED)
 381                 return;
 382
 383         if (!(o->flags & REFERENCED))
 384                 add_head_def(info[pack_ix], o->sha1);
 385         else if ((o->flags & REFERENCED) && !(o->flags & INTERNAL)) {
 386                 int i;
 387
 388                 /* Which pack contains this object?  That is what
 389                  * pack_ix can depend on.  We earlier sorted info
 390                  * array from youngest to oldest, so try newer packs
 391                  * first to favor them here.
 392                  */
 393                 for (i = num_pack - 1; 0 <= i; i--) {
 394                         struct packed_git *p = info[i]->p;
 395                         struct pack_entry ent;
 396                         if (find_pack_entry_one(o->sha1, &ent, p)) {
 397                                 info[pack_ix]->dep[i] = 1;
 398                                 break;
 399                         }
 400                 }
 401         }
 402         o->flags |= EMITTED;
 403 }
 404
 405 static void find_pack_info_one(int pack_ix)
 406 {
 407         unsigned char sha1[20];
 408         struct object *o;
 409         struct object_list *ref;
 410         int i;
 411         struct packed_git *p = info[pack_ix]->p;
 412         int num = num_packed_objects(p);
 413
 414         /* Scan objects, clear flags from all the edge ones and
 415          * internal ones, possibly marked in the previous round.
 416          */
 417         for (i = 0; i < num; i++) {
 418                 if (nth_packed_object_sha1(p, i, sha1))
 419                         die("corrupt pack file %s?", p->pack_name);
 420                 if ((o = lookup_object(sha1)) == NULL)
 421                         die("cannot parse %s", sha1_to_hex(sha1));
 422                 for (ref = o->refs; ref; ref = ref->next)
 423                         ref->item->flags = 0;
 424                 o->flags = 0;
 425         }
 426
 427         /* Mark all the internal ones */
 428         for (i = 0; i < num; i++) {
 429                 if (nth_packed_object_sha1(p, i, sha1))
 430                         die("corrupt pack file %s?", p->pack_name);
 431                 if ((o = lookup_object(sha1)) == NULL)
 432                         die("cannot find %s", sha1_to_hex(sha1));
 433                 for (ref = o->refs; ref; ref = ref->next)
 434                         ref->item->flags |= REFERENCED;
 435                 o->flags |= INTERNAL;
 436         }
 437
 438         for (i = 0; i < num; i++) {
 439                 if (nth_packed_object_sha1(p, i, sha1))
 440                         die("corrupt pack file %s?", p->pack_name);
 441                 if ((o = lookup_object(sha1)) == NULL)
 442                         die("cannot find %s", sha1_to_hex(sha1));
 443
 444                 show(o, pack_ix);
 445                 for (ref = o->refs; ref; ref = ref->next)
 446                         show(ref->item, pack_ix);
 447         }
 448
 449 }
 450
 451 static void find_pack_info(void)
 452 {
 453         int i;
 454         for (i = 0; i < num_pack; i++) {
 455                 /* The packed objects are cast in stone, and a head
 456                  * in a pack will stay as head, so is the set of missing
 457                  * objects.  If the repo has been reorganized and we
 458                  * are missing some packs available back then, we have
 459                  * already discarded the info read from the file, so
 460                  * we will find (old_num < 0) in that case.
 461                  */
 462                 if (0 <= info[i]->old_num)
 463                         continue;
 464                 find_pack_info_one(i);
 465         }
 466 }
 467
 468 static int update_info_packs(int force)
 469 {
 470         char infofile[PATH_MAX];
 471         char name[PATH_MAX];
 472         int namelen;
 473         FILE *fp;
 474
 475         namelen = sprintf(infofile, "%s/info/packs", get_object_directory());
 476         strcpy(name, infofile);
 477         strcpy(name + namelen, "+");
 478
 479         init_pack_info(infofile, force);
 480         find_pack_info();
 481
 482         safe_create_leading_directories(name);
 483         fp = fopen(name, "w");
 484         if (!fp)
 485                 return error("cannot open %s", name);
 486         write_pack_info_file(fp);
 487         fclose(fp);
 488         rename(name, infofile);
 489         return 0;
 490 }
 491
 492 /* public */
 493 int update_server_info(int force)
 494 {
 495         /* We would add more dumb-server support files later,
 496          * including index of available pack files and their
 497          * intended audiences.
 498          */
 499         int errs = 0;
 500
 501         errs = errs | update_info_refs(force);
 502         errs = errs | update_info_packs(force);
 503
 504         return errs;
 505 }