Andrew's git - gitweb.git/blob

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