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         } else if (o->type == tree_type) {
  63                 struct tree *tree = (struct tree *)o;
  64                 struct tree_entry_list *e, *n;
  65                 for (e = tree->entries; e; e = n) {
  66                         free(e->name);
  67                         e->name = NULL;
  68                         n = e->next;
  69                         free(e);
  70                 }
  71                 tree->entries = NULL;
  72         }
  73         return o;
  74 }
  75
  76 static struct pack_info *find_pack_by_name(const char *name)
  77 {
  78         int i;
  79         for (i = 0; i < num_pack; i++) {
  80                 struct packed_git *p = info[i]->p;
  81                 /* skip "/pack/" after ".git/objects" */
  82                 if (!strcmp(p->pack_name + objdirlen + 6, name))
  83                         return info[i];
  84         }
  85         return NULL;
  86 }
  87
  88 static struct pack_info *find_pack_by_old_num(int old_num)
  89 {
  90         int i;
  91         for (i = 0; i < num_pack; i++)
  92                 if (info[i]->old_num == old_num)
  93                         return info[i];
  94         return NULL;
  95 }
  96
  97 static int add_head_def(struct pack_info *this, unsigned char *sha1)
  98 {
  99         if (this->nr_alloc <= this->nr_heads) {
 100                 this->nr_alloc = alloc_nr(this->nr_alloc);
 101                 this->head = xrealloc(this->head, this->nr_alloc * 20);
 102         }
 103         memcpy(this->head[this->nr_heads++], sha1, 20);
 104         return 0;
 105 }
 106
 107 /* Returns non-zero when we detect that the info in the
 108  * old file is useless.
 109  */
 110 static int parse_pack_def(const char *line, int old_cnt)
 111 {
 112         struct pack_info *i = find_pack_by_name(line + 2);
 113         if (i) {
 114                 i->old_num = old_cnt;
 115                 return 0;
 116         }
 117         else {
 118                 /* The file describes a pack that is no longer here;
 119                  * dependencies between packs needs to be recalculated.
 120                  */
 121                 return 1;
 122         }
 123 }
 124
 125 /* Returns non-zero when we detect that the info in the
 126  * old file is useless.
 127  */
 128 static int parse_depend_def(char *line)
 129 {
 130         unsigned long num;
 131         char *cp, *ep;
 132         struct pack_info *this, *that;
 133
 134         cp = line + 2;
 135         num = strtoul(cp, &ep, 10);
 136         if (ep == cp)
 137                 return error("invalid input %s", line);
 138         this = find_pack_by_old_num(num);
 139         if (!this)
 140                 return 0;
 141         while (ep && *(cp = ep)) {
 142                 num = strtoul(cp, &ep, 10);
 143                 if (ep == cp)
 144                         break;
 145                 that = find_pack_by_old_num(num);
 146                 if (!that)
 147                         /* The pack this one depends on does not
 148                          * exist; this should not happen because
 149                          * we write out the list of packs first and
 150                          * then dependency information, but it means
 151                          * the file is useless anyway.
 152                          */
 153                         return 1;
 154                 this->dep[that->new_num] = 1;
 155         }
 156         return 0;
 157 }
 158
 159 /* Returns non-zero when we detect that the info in the
 160  * old file is useless.
 161  */
 162 static int parse_head_def(char *line)
 163 {
 164         unsigned char sha1[20];
 165         unsigned long num;
 166         char *cp, *ep;
 167         struct pack_info *this;
 168         struct object *o;
 169
 170         cp = line + 2;
 171         num = strtoul(cp, &ep, 10);
 172         if (ep == cp || *ep++ != ' ')
 173                 return error("invalid input ix %s", line);
 174         this = find_pack_by_old_num(num);
 175         if (!this)
 176                 return 1; /* You know the drill. */
 177         if (get_sha1_hex(ep, sha1) || ep[40] != ' ')
 178                 return error("invalid input sha1 %s (%s)", line, ep);
 179         if ((o = parse_object_cheap(sha1)) == NULL)
 180                 return error("no such object: %s", line);
 181         return add_head_def(this, sha1);
 182 }
 183
 184 /* Returns non-zero when we detect that the info in the
 185  * old file is useless.
 186  */
 187 static int read_pack_info_file(const char *infofile)
 188 {
 189         FILE *fp;
 190         char line[1000];
 191         int old_cnt = 0;
 192
 193         fp = fopen(infofile, "r");
 194         if (!fp)
 195                 return 1; /* nonexisting is not an error. */
 196
 197         while (fgets(line, sizeof(line), fp)) {
 198                 int len = strlen(line);
 199                 if (line[len-1] == '\n')
 200                         line[len-1] = 0;
 201
 202                 switch (line[0]) {
 203                 case 'P': /* P name */
 204                         if (parse_pack_def(line, old_cnt++))
 205                                 goto out_stale;
 206                         break;
 207                 case 'D': /* D ix dep-ix1 dep-ix2... */
 208                         if (parse_depend_def(line))
 209                                 goto out_stale;
 210                         break;
 211                 case 'T': /* T ix sha1 type */
 212                         if (parse_head_def(line))
 213                                 goto out_stale;
 214                         break;
 215                 default:
 216                         error("unrecognized: %s", line);
 217                         break;
 218                 }
 219         }
 220         fclose(fp);
 221         return 0;
 222  out_stale:
 223         fclose(fp);
 224         return 1;
 225 }
 226
 227 /* We sort the packs according to the date of the latest commit.  That
 228  * in turn indicates how young the pack is, and in general we would
 229  * want to depend on younger packs.
 230  */
 231 static unsigned long get_latest_commit_date(struct packed_git *p)
 232 {
 233         unsigned char sha1[20];
 234         struct object *o;
 235         int num = num_packed_objects(p);
 236         int i;
 237         unsigned long latest = 0;
 238
 239         for (i = 0; i < num; i++) {
 240                 if (nth_packed_object_sha1(p, i, sha1))
 241                         die("corrupt pack file %s?", p->pack_name);
 242                 if ((o = parse_object_cheap(sha1)) == NULL)
 243                         die("cannot parse %s", sha1_to_hex(sha1));
 244                 if (o->type == commit_type) {
 245                         struct commit *commit = (struct commit *)o;
 246                         if (latest < commit->date)
 247                                 latest = commit->date;
 248                 }
 249         }
 250         return latest;
 251 }
 252
 253 static int compare_info(const void *a_, const void *b_)
 254 {
 255         struct pack_info * const* a = a_;
 256         struct pack_info * const* b = b_;
 257
 258         if (0 <= (*a)->old_num && 0 <= (*b)->old_num)
 259                 /* Keep the order in the original */
 260                 return (*a)->old_num - (*b)->old_num;
 261         else if (0 <= (*a)->old_num)
 262                 /* Only A existed in the original so B is obviously newer */
 263                 return -1;
 264         else if (0 <= (*b)->old_num)
 265                 /* The other way around. */
 266                 return 1;
 267
 268         if ((*a)->latest < (*b)->latest)
 269                 return -1;
 270         else if ((*a)->latest == (*b)->latest)
 271                 return 0;
 272         else
 273                 return 1;
 274 }
 275
 276 static void init_pack_info(const char *infofile, int force)
 277 {
 278         struct packed_git *p;
 279         int stale;
 280         int i = 0;
 281         char *dep_temp;
 282
 283         objdir = get_object_directory();
 284         objdirlen = strlen(objdir);
 285
 286         prepare_packed_git();
 287         for (p = packed_git; p; p = p->next) {
 288                 /* we ignore things on alternate path since they are
 289                  * not available to the pullers in general.
 290                  */
 291                 if (strncmp(p->pack_name, objdir, objdirlen) ||
 292                     strncmp(p->pack_name + objdirlen, "/pack/", 6))
 293                         continue;
 294                 i++;
 295         }
 296         num_pack = i;
 297         info = xcalloc(num_pack, sizeof(struct pack_info *));
 298         for (i = 0, p = packed_git; p; p = p->next) {
 299                 if (strncmp(p->pack_name, objdir, objdirlen) ||
 300                     p->pack_name[objdirlen] != '/')
 301                         continue;
 302                 info[i] = xcalloc(1, sizeof(struct pack_info) + num_pack);
 303                 info[i]->p = p;
 304                 info[i]->old_num = -1;
 305                 i++;
 306         }
 307
 308         if (infofile && !force)
 309                 stale = read_pack_info_file(infofile);
 310         else
 311                 stale = 1;
 312
 313         for (i = 0; i < num_pack; i++) {
 314                 if (stale) {
 315                         info[i]->old_num = -1;
 316                         memset(info[i]->dep, 0, num_pack);
 317                         info[i]->nr_heads = 0;
 318                 }
 319                 if (info[i]->old_num < 0)
 320                         info[i]->latest = get_latest_commit_date(info[i]->p);
 321         }
 322
 323         qsort(info, num_pack, sizeof(info[0]), compare_info);
 324         for (i = 0; i < num_pack; i++)
 325                 info[i]->new_num = i;
 326
 327         /* we need to fix up the dependency information
 328          * for the old ones.
 329          */
 330         dep_temp = NULL;
 331         for (i = 0; i < num_pack; i++) {
 332                 int old;
 333
 334                 if (info[i]->old_num < 0)
 335                         continue;
 336                 if (! dep_temp)
 337                         dep_temp = xmalloc(num_pack);
 338                 memset(dep_temp, 0, num_pack);
 339                 for (old = 0; old < num_pack; old++) {
 340                         struct pack_info *base;
 341                         if (!info[i]->dep[old])
 342                                 continue;
 343                         base = find_pack_by_old_num(old);
 344                         if (!base)
 345                                 die("internal error renumbering");
 346                         dep_temp[base->new_num] = 1;
 347                 }
 348                 memcpy(info[i]->dep, dep_temp, num_pack);
 349         }
 350         free(dep_temp);
 351 }
 352
 353 static void write_pack_info_file(FILE *fp)
 354 {
 355         int i, j;
 356         for (i = 0; i < num_pack; i++)
 357                 fprintf(fp, "P %s\n", info[i]->p->pack_name + objdirlen + 6);
 358
 359         for (i = 0; i < num_pack; i++) {
 360                 fprintf(fp, "D %1d", i);
 361                 for (j = 0; j < num_pack; j++) {
 362                         if ((i == j) || !(info[i]->dep[j]))
 363                                 continue;
 364                         fprintf(fp, " %1d", j);
 365                 }
 366                 fputc('\n', fp);
 367         }
 368
 369         for (i = 0; i < num_pack; i++) {
 370                 struct pack_info *this = info[i];
 371                 for (j = 0; j < this->nr_heads; j++) {
 372                         struct object *o = lookup_object(this->head[j]);
 373                         fprintf(fp, "T %1d %s %s\n",
 374                                 i, sha1_to_hex(this->head[j]), o->type);
 375                 }
 376         }
 377
 378 }
 379
 380 #define REFERENCED 01
 381 #define INTERNAL  02
 382 #define EMITTED   04
 383
 384 static void show(struct object *o, int pack_ix)
 385 {
 386         /*
 387          * We are interested in objects that are not referenced,
 388          * and objects that are referenced but not internal.
 389          */
 390         if (o->flags & EMITTED)
 391                 return;
 392
 393         if (!(o->flags & REFERENCED))
 394                 add_head_def(info[pack_ix], o->sha1);
 395         else if ((o->flags & REFERENCED) && !(o->flags & INTERNAL)) {
 396                 int i;
 397
 398                 /* Which pack contains this object?  That is what
 399                  * pack_ix can depend on.  We earlier sorted info
 400                  * array from youngest to oldest, so try newer packs
 401                  * first to favor them here.
 402                  */
 403                 for (i = num_pack - 1; 0 <= i; i--) {
 404                         struct packed_git *p = info[i]->p;
 405                         struct pack_entry ent;
 406                         if (find_pack_entry_one(o->sha1, &ent, p)) {
 407                                 info[pack_ix]->dep[i] = 1;
 408                                 break;
 409                         }
 410                 }
 411         }
 412         o->flags |= EMITTED;
 413 }
 414
 415 static void find_pack_info_one(int pack_ix)
 416 {
 417         unsigned char sha1[20];
 418         struct object *o;
 419         struct object_list *ref;
 420         int i;
 421         struct packed_git *p = info[pack_ix]->p;
 422         int num = num_packed_objects(p);
 423
 424         /* Scan objects, clear flags from all the edge ones and
 425          * internal ones, possibly marked in the previous round.
 426          */
 427         for (i = 0; i < num; i++) {
 428                 if (nth_packed_object_sha1(p, i, sha1))
 429                         die("corrupt pack file %s?", p->pack_name);
 430                 if ((o = lookup_object(sha1)) == NULL)
 431                         die("cannot parse %s", sha1_to_hex(sha1));
 432                 for (ref = o->refs; ref; ref = ref->next)
 433                         ref->item->flags = 0;
 434                 o->flags = 0;
 435         }
 436
 437         /* Mark all the internal ones */
 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                 for (ref = o->refs; ref; ref = ref->next)
 444                         ref->item->flags |= REFERENCED;
 445                 o->flags |= INTERNAL;
 446         }
 447
 448         for (i = 0; i < num; i++) {
 449                 if (nth_packed_object_sha1(p, i, sha1))
 450                         die("corrupt pack file %s?", p->pack_name);
 451                 if ((o = lookup_object(sha1)) == NULL)
 452                         die("cannot find %s", sha1_to_hex(sha1));
 453
 454                 show(o, pack_ix);
 455                 for (ref = o->refs; ref; ref = ref->next)
 456                         show(ref->item, pack_ix);
 457         }
 458
 459 }
 460
 461 static void find_pack_info(void)
 462 {
 463         int i;
 464         for (i = 0; i < num_pack; i++) {
 465                 /* The packed objects are cast in stone, and a head
 466                  * in a pack will stay as head, so is the set of missing
 467                  * objects.  If the repo has been reorganized and we
 468                  * are missing some packs available back then, we have
 469                  * already discarded the info read from the file, so
 470                  * we will find (old_num < 0) in that case.
 471                  */
 472                 if (0 <= info[i]->old_num)
 473                         continue;
 474                 find_pack_info_one(i);
 475         }
 476 }
 477
 478 static int update_info_packs(int force)
 479 {
 480         char infofile[PATH_MAX];
 481         char name[PATH_MAX];
 482         int namelen;
 483         FILE *fp;
 484
 485         namelen = sprintf(infofile, "%s/info/packs", get_object_directory());
 486         strcpy(name, infofile);
 487         strcpy(name + namelen, "+");
 488
 489         init_pack_info(infofile, force);
 490         find_pack_info();
 491
 492         safe_create_leading_directories(name);
 493         fp = fopen(name, "w");
 494         if (!fp)
 495                 return error("cannot open %s", name);
 496         write_pack_info_file(fp);
 497         fclose(fp);
 498         rename(name, infofile);
 499         return 0;
 500 }
 501
 502 /* public */
 503 int update_server_info(int force)
 504 {
 505         /* We would add more dumb-server support files later,
 506          * including index of available pack files and their
 507          * intended audiences.
 508          */
 509         int errs = 0;
 510
 511         errs = errs | update_info_refs(force);
 512         errs = errs | update_info_packs(force);
 513
 514         return errs;
 515 }