Andrew's git - gitweb.git/blob

   1#include "cache.h"
   2#include "sha1-lookup.h"
   3#include "refs.h"
   4#include "commit.h"
   5
   6/*
   7 * An array of replacements.  The array is kept sorted by the original
   8 * sha1.
   9 */
  10static struct replace_object {
  11        unsigned char original[20];
  12        unsigned char replacement[20];
  13} **replace_object;
  14
  15static int replace_object_alloc, replace_object_nr;
  16
  17static const unsigned char *replace_sha1_access(size_t index, void *table)
  18{
  19        struct replace_object **replace = table;
  20        return replace[index]->original;
  21}
  22
  23static int replace_object_pos(const unsigned char *sha1)
  24{
  25        return sha1_pos(sha1, replace_object, replace_object_nr,
  26                        replace_sha1_access);
  27}
  28
  29static int register_replace_object(struct replace_object *replace,
  30                                   int ignore_dups)
  31{
  32        int pos = replace_object_pos(replace->original);
  33
  34        if (0 <= pos) {
  35                if (ignore_dups)
  36                        free(replace);
  37                else {
  38                        free(replace_object[pos]);
  39                        replace_object[pos] = replace;
  40                }
  41                return 1;
  42        }
  43        pos = -pos - 1;
  44        ALLOC_GROW(replace_object, replace_object_nr + 1, replace_object_alloc);
  45        replace_object_nr++;
  46        if (pos < replace_object_nr)
  47                memmove(replace_object + pos + 1,
  48                        replace_object + pos,
  49                        (replace_object_nr - pos - 1) *
  50                        sizeof(*replace_object));
  51        replace_object[pos] = replace;
  52        return 0;
  53}
  54
  55static int register_replace_ref(const char *refname,
  56                                const unsigned char *sha1,
  57                                int flag, void *cb_data)
  58{
  59        /* Get sha1 from refname */
  60        const char *slash = strrchr(refname, '/');
  61        const char *hash = slash ? slash + 1 : refname;
  62        struct replace_object *repl_obj = xmalloc(sizeof(*repl_obj));
  63
  64        if (strlen(hash) != 40 || get_sha1_hex(hash, repl_obj->original)) {
  65                free(repl_obj);
  66                warning("bad replace ref name: %s", refname);
  67                return 0;
  68        }
  69
  70        /* Copy sha1 from the read ref */
  71        hashcpy(repl_obj->replacement, sha1);
  72
  73        /* Register new object */
  74        if (register_replace_object(repl_obj, 1))
  75                die("duplicate replace ref: %s", refname);
  76
  77        return 0;
  78}
  79
  80static void prepare_replace_object(void)
  81{
  82        static int replace_object_prepared;
  83
  84        if (replace_object_prepared)
  85                return;
  86
  87        for_each_replace_ref(register_replace_ref, NULL);
  88        replace_object_prepared = 1;
  89        if (!replace_object_nr)
  90                check_replace_refs = 0;
  91}
  92
  93/* We allow "recursive" replacement. Only within reason, though */
  94#define MAXREPLACEDEPTH 5
  95
  96/*
  97 * If a replacement for object sha1 has been set up, return the
  98 * replacement object's name (replaced recursively, if necessary).
  99 * The return value is either sha1 or a pointer to a
 100 * permanently-allocated value.  This function always respects replace
 101 * references, regardless of the value of check_replace_refs.
 102 */
 103const unsigned char *do_lookup_replace_object(const unsigned char *sha1)
 104{
 105        int pos, depth = MAXREPLACEDEPTH;
 106        const unsigned char *cur = sha1;
 107
 108        prepare_replace_object();
 109
 110        /* Try to recursively replace the object */
 111        do {
 112                if (--depth < 0)
 113                        die("replace depth too high for object %s",
 114                            sha1_to_hex(sha1));
 115
 116                pos = replace_object_pos(cur);
 117                if (0 <= pos)
 118                        cur = replace_object[pos]->replacement;
 119        } while (0 <= pos);
 120
 121        return cur;
 122}