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, int flag, void *cb_data)
  11 {
  12         struct object *o = parse_object(sha1);
  13         if (!o)
  14                 return -1;
  15
  16         fprintf(info_ref_fp, "%s        %s\n", sha1_to_hex(sha1), path);
  17         if (o->type == OBJ_TAG) {
  18                 o = deref_tag(o, path, 0);
  19                 if (o)
  20                         fprintf(info_ref_fp, "%s        %s^{}\n",
  21                                 sha1_to_hex(o->sha1), path);
  22         }
  23         return 0;
  24 }
  25
  26 static int update_info_refs(int force)
  27 {
  28         char *path0 = git_pathdup("info/refs");
  29         int len = strlen(path0);
  30         char *path1 = xmalloc(len + 2);
  31
  32         strcpy(path1, path0);
  33         strcpy(path1 + len, "+");
  34
  35         safe_create_leading_directories(path0);
  36         info_ref_fp = fopen(path1, "w");
  37         if (!info_ref_fp)
  38                 return error("unable to update %s", path1);
  39         for_each_ref(add_info_ref, NULL);
  40         fclose(info_ref_fp);
  41         adjust_shared_perm(path1);
  42         rename(path1, path0);
  43         free(path0);
  44         free(path1);
  45         return 0;
  46 }
  47
  48 /* packs */
  49 static struct pack_info {
  50         struct packed_git *p;
  51         int old_num;
  52         int new_num;
  53         int nr_alloc;
  54         int nr_heads;
  55         unsigned char (*head)[20];
  56 } **info;
  57 static int num_pack;
  58 static const char *objdir;
  59 static int objdirlen;
  60
  61 static struct pack_info *find_pack_by_name(const char *name)
  62 {
  63         int i;
  64         for (i = 0; i < num_pack; i++) {
  65                 struct packed_git *p = info[i]->p;
  66                 /* skip "/pack/" after ".git/objects" */
  67                 if (!strcmp(p->pack_name + objdirlen + 6, name))
  68                         return info[i];
  69         }
  70         return NULL;
  71 }
  72
  73 /* Returns non-zero when we detect that the info in the
  74  * old file is useless.
  75  */
  76 static int parse_pack_def(const char *line, int old_cnt)
  77 {
  78         struct pack_info *i = find_pack_by_name(line + 2);
  79         if (i) {
  80                 i->old_num = old_cnt;
  81                 return 0;
  82         }
  83         else {
  84                 /* The file describes a pack that is no longer here */
  85                 return 1;
  86         }
  87 }
  88
  89 /* Returns non-zero when we detect that the info in the
  90  * old file is useless.
  91  */
  92 static int read_pack_info_file(const char *infofile)
  93 {
  94         FILE *fp;
  95         char line[1000];
  96         int old_cnt = 0;
  97
  98         fp = fopen(infofile, "r");
  99         if (!fp)
 100                 return 1; /* nonexistent is not an error. */
 101
 102         while (fgets(line, sizeof(line), fp)) {
 103                 int len = strlen(line);
 104                 if (len && line[len-1] == '\n')
 105                         line[--len] = 0;
 106
 107                 if (!len)
 108                         continue;
 109
 110                 switch (line[0]) {
 111                 case 'P': /* P name */
 112                         if (parse_pack_def(line, old_cnt++))
 113                                 goto out_stale;
 114                         break;
 115                 case 'D': /* we used to emit D but that was misguided. */
 116                 case 'T': /* we used to emit T but nobody uses it. */
 117                         goto out_stale;
 118                 default:
 119                         error("unrecognized: %s", line);
 120                         break;
 121                 }
 122         }
 123         fclose(fp);
 124         return 0;
 125  out_stale:
 126         fclose(fp);
 127         return 1;
 128 }
 129
 130 static int compare_info(const void *a_, const void *b_)
 131 {
 132         struct pack_info *const *a = a_;
 133         struct pack_info *const *b = b_;
 134
 135         if (0 <= (*a)->old_num && 0 <= (*b)->old_num)
 136                 /* Keep the order in the original */
 137                 return (*a)->old_num - (*b)->old_num;
 138         else if (0 <= (*a)->old_num)
 139                 /* Only A existed in the original so B is obviously newer */
 140                 return -1;
 141         else if (0 <= (*b)->old_num)
 142                 /* The other way around. */
 143                 return 1;
 144
 145         /* then it does not matter but at least keep the comparison stable */
 146         if ((*a)->p == (*b)->p)
 147                 return 0;
 148         else if ((*a)->p < (*b)->p)
 149                 return -1;
 150         else
 151                 return 1;
 152 }
 153
 154 static void init_pack_info(const char *infofile, int force)
 155 {
 156         struct packed_git *p;
 157         int stale;
 158         int i = 0;
 159
 160         objdir = get_object_directory();
 161         objdirlen = strlen(objdir);
 162
 163         prepare_packed_git();
 164         for (p = packed_git; p; p = p->next) {
 165                 /* we ignore things on alternate path since they are
 166                  * not available to the pullers in general.
 167                  */
 168                 if (!p->pack_local)
 169                         continue;
 170                 i++;
 171         }
 172         num_pack = i;
 173         info = xcalloc(num_pack, sizeof(struct pack_info *));
 174         for (i = 0, p = packed_git; p; p = p->next) {
 175                 if (!p->pack_local)
 176                         continue;
 177                 info[i] = xcalloc(1, sizeof(struct pack_info));
 178                 info[i]->p = p;
 179                 info[i]->old_num = -1;
 180                 i++;
 181         }
 182
 183         if (infofile && !force)
 184                 stale = read_pack_info_file(infofile);
 185         else
 186                 stale = 1;
 187
 188         for (i = 0; i < num_pack; i++) {
 189                 if (stale) {
 190                         info[i]->old_num = -1;
 191                         info[i]->nr_heads = 0;
 192                 }
 193         }
 194
 195         /* renumber them */
 196         qsort(info, num_pack, sizeof(info[0]), compare_info);
 197         for (i = 0; i < num_pack; i++)
 198                 info[i]->new_num = i;
 199 }
 200
 201 static void write_pack_info_file(FILE *fp)
 202 {
 203         int i;
 204         for (i = 0; i < num_pack; i++)
 205                 fprintf(fp, "P %s\n", info[i]->p->pack_name + objdirlen + 6);
 206         fputc('\n', fp);
 207 }
 208
 209 static int update_info_packs(int force)
 210 {
 211         char infofile[PATH_MAX];
 212         char name[PATH_MAX];
 213         int namelen;
 214         FILE *fp;
 215
 216         namelen = sprintf(infofile, "%s/info/packs", get_object_directory());
 217         strcpy(name, infofile);
 218         strcpy(name + namelen, "+");
 219
 220         init_pack_info(infofile, force);
 221
 222         safe_create_leading_directories(name);
 223         fp = fopen(name, "w");
 224         if (!fp)
 225                 return error("cannot open %s", name);
 226         write_pack_info_file(fp);
 227         fclose(fp);
 228         adjust_shared_perm(name);
 229         rename(name, infofile);
 230         return 0;
 231 }
 232
 233 /* public */
 234 int update_server_info(int force)
 235 {
 236         /* We would add more dumb-server support files later,
 237          * including index of available pack files and their
 238          * intended audiences.
 239          */
 240         int errs = 0;
 241
 242         errs = errs | update_info_refs(force);
 243         errs = errs | update_info_packs(force);
 244
 245         /* remove leftover rev-cache file if there is any */
 246         unlink_or_warn(git_path("info/rev-cache"));
 247
 248         return errs;
 249 }