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         struct object *o = parse_object(sha1);
  13
  14         fprintf(info_ref_fp, "%s        %s\n", sha1_to_hex(sha1), path);
  15         if (o->type == tag_type) {
  16                 o = deref_tag(o, path, 0);
  17                 if (o)
  18                         fprintf(info_ref_fp, "%s        %s^{}\n",
  19                                 sha1_to_hex(o->sha1), path);
  20         }
  21         return 0;
  22 }
  23
  24 static int update_info_refs(int force)
  25 {
  26         char *path0 = strdup(git_path("info/refs"));
  27         int len = strlen(path0);
  28         char *path1 = xmalloc(len + 2);
  29
  30         strcpy(path1, path0);
  31         strcpy(path1 + len, "+");
  32
  33         safe_create_leading_directories(path0);
  34         info_ref_fp = fopen(path1, "w");
  35         if (!info_ref_fp)
  36                 return error("unable to update %s", path0);
  37         for_each_ref(add_info_ref);
  38         fclose(info_ref_fp);
  39         rename(path1, path0);
  40         free(path0);
  41         free(path1);
  42         return 0;
  43 }
  44
  45 /* packs */
  46 static struct pack_info {
  47         struct packed_git *p;
  48         int old_num;
  49         int new_num;
  50         int nr_alloc;
  51         int nr_heads;
  52         unsigned char (*head)[20];
  53 } **info;
  54 static int num_pack;
  55 static const char *objdir;
  56 static int objdirlen;
  57
  58 static struct object *parse_object_cheap(const unsigned char *sha1)
  59 {
  60         struct object *o;
  61
  62         if ((o = parse_object(sha1)) == NULL)
  63                 return NULL;
  64         if (o->type == commit_type) {
  65                 struct commit *commit = (struct commit *)o;
  66                 free(commit->buffer);
  67                 commit->buffer = NULL;
  68         } else if (o->type == tree_type) {
  69                 struct tree *tree = (struct tree *)o;
  70                 struct tree_entry_list *e, *n;
  71                 for (e = tree->entries; e; e = n) {
  72                         free(e->name);
  73                         e->name = NULL;
  74                         n = e->next;
  75                         free(e);
  76                 }
  77                 tree->entries = NULL;
  78         }
  79         return o;
  80 }
  81
  82 static struct pack_info *find_pack_by_name(const char *name)
  83 {
  84         int i;
  85         for (i = 0; i < num_pack; i++) {
  86                 struct packed_git *p = info[i]->p;
  87                 /* skip "/pack/" after ".git/objects" */
  88                 if (!strcmp(p->pack_name + objdirlen + 6, name))
  89                         return info[i];
  90         }
  91         return NULL;
  92 }
  93
  94 static struct pack_info *find_pack_by_old_num(int old_num)
  95 {
  96         int i;
  97         for (i = 0; i < num_pack; i++)
  98                 if (info[i]->old_num == old_num)
  99                         return info[i];
 100         return NULL;
 101 }
 102
 103 /* Returns non-zero when we detect that the info in the
 104  * old file is useless.
 105  */
 106 static int parse_pack_def(const char *line, int old_cnt)
 107 {
 108         struct pack_info *i = find_pack_by_name(line + 2);
 109         if (i) {
 110                 i->old_num = old_cnt;
 111                 return 0;
 112         }
 113         else {
 114                 /* The file describes a pack that is no longer here */
 115                 return 1;
 116         }
 117 }
 118
 119 /* Returns non-zero when we detect that the info in the
 120  * old file is useless.
 121  */
 122 static int read_pack_info_file(const char *infofile)
 123 {
 124         FILE *fp;
 125         char line[1000];
 126         int old_cnt = 0;
 127
 128         fp = fopen(infofile, "r");
 129         if (!fp)
 130                 return 1; /* nonexisting is not an error. */
 131
 132         while (fgets(line, sizeof(line), fp)) {
 133                 int len = strlen(line);
 134                 if (line[len-1] == '\n')
 135                         line[len-1] = 0;
 136
 137                 switch (line[0]) {
 138                 case 'P': /* P name */
 139                         if (parse_pack_def(line, old_cnt++))
 140                                 goto out_stale;
 141                         break;
 142                 case 'D': /* we used to emit D but that was misguided. */
 143                         goto out_stale;
 144                         break;
 145                 case 'T': /* we used to emit T but nobody uses it. */
 146                         goto out_stale;
 147                         break;
 148                 default:
 149                         error("unrecognized: %s", line);
 150                         break;
 151                 }
 152         }
 153         fclose(fp);
 154         return 0;
 155  out_stale:
 156         fclose(fp);
 157         return 1;
 158 }
 159
 160 static int compare_info(const void *a_, const void *b_)
 161 {
 162         struct pack_info * const* a = a_;
 163         struct pack_info * const* b = b_;
 164
 165         if (0 <= (*a)->old_num && 0 <= (*b)->old_num)
 166                 /* Keep the order in the original */
 167                 return (*a)->old_num - (*b)->old_num;
 168         else if (0 <= (*a)->old_num)
 169                 /* Only A existed in the original so B is obviously newer */
 170                 return -1;
 171         else if (0 <= (*b)->old_num)
 172                 /* The other way around. */
 173                 return 1;
 174
 175         /* then it does not matter but at least keep the comparison stable */
 176         return (*a)->p - (*b)->p;
 177 }
 178
 179 static void init_pack_info(const char *infofile, int force)
 180 {
 181         struct packed_git *p;
 182         int stale;
 183         int i = 0;
 184
 185         objdir = get_object_directory();
 186         objdirlen = strlen(objdir);
 187
 188         prepare_packed_git();
 189         for (p = packed_git; p; p = p->next) {
 190                 /* we ignore things on alternate path since they are
 191                  * not available to the pullers in general.
 192                  */
 193                 if (!p->pack_local)
 194                         continue;
 195                 i++;
 196         }
 197         num_pack = i;
 198         info = xcalloc(num_pack, sizeof(struct pack_info *));
 199         for (i = 0, p = packed_git; p; p = p->next) {
 200                 if (!p->pack_local)
 201                         continue;
 202                 info[i] = xcalloc(1, sizeof(struct pack_info));
 203                 info[i]->p = p;
 204                 info[i]->old_num = -1;
 205                 i++;
 206         }
 207
 208         if (infofile && !force)
 209                 stale = read_pack_info_file(infofile);
 210         else
 211                 stale = 1;
 212
 213         for (i = 0; i < num_pack; i++) {
 214                 if (stale) {
 215                         info[i]->old_num = -1;
 216                         info[i]->nr_heads = 0;
 217                 }
 218         }
 219
 220         /* renumber them */
 221         qsort(info, num_pack, sizeof(info[0]), compare_info);
 222         for (i = 0; i < num_pack; i++)
 223                 info[i]->new_num = i;
 224 }
 225
 226 static void write_pack_info_file(FILE *fp)
 227 {
 228         int i;
 229         for (i = 0; i < num_pack; i++)
 230                 fprintf(fp, "P %s\n", info[i]->p->pack_name + objdirlen + 6);
 231 }
 232
 233 static int update_info_packs(int force)
 234 {
 235         char infofile[PATH_MAX];
 236         char name[PATH_MAX];
 237         int namelen;
 238         FILE *fp;
 239
 240         namelen = sprintf(infofile, "%s/info/packs", get_object_directory());
 241         strcpy(name, infofile);
 242         strcpy(name + namelen, "+");
 243
 244         init_pack_info(infofile, force);
 245
 246         safe_create_leading_directories(name);
 247         fp = fopen(name, "w");
 248         if (!fp)
 249                 return error("cannot open %s", name);
 250         write_pack_info_file(fp);
 251         fclose(fp);
 252         rename(name, infofile);
 253         return 0;
 254 }
 255
 256 /* public */
 257 int update_server_info(int force)
 258 {
 259         /* We would add more dumb-server support files later,
 260          * including index of available pack files and their
 261          * intended audiences.
 262          */
 263         int errs = 0;
 264
 265         errs = errs | update_info_refs(force);
 266         errs = errs | update_info_packs(force);
 267
 268         /* remove leftover rev-cache file if there is any */
 269         unlink(git_path("info/rev-cache"));
 270
 271         return errs;
 272 }