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        ALLOC_GROW(replace_object, replace_object_nr + 1, replace_object_alloc);
  40        replace_object_nr++;
  41        if (pos < replace_object_nr)
  42                memmove(replace_object + pos + 1,
  43                        replace_object + pos,
  44                        (replace_object_nr - pos - 1) *
  45                        sizeof(*replace_object));
  46        replace_object[pos] = replace;
  47        return 0;
  48}
  49
  50static int register_replace_ref(const char *refname,
  51                                const unsigned char *sha1,
  52                                int flag, void *cb_data)
  53{
  54        /* Get sha1 from refname */
  55        const char *slash = strrchr(refname, '/');
  56        const char *hash = slash ? slash + 1 : refname;
  57        struct replace_object *repl_obj = xmalloc(sizeof(*repl_obj));
  58
  59        if (strlen(hash) != 40 || get_sha1_hex(hash, repl_obj->sha1[0])) {
  60                free(repl_obj);
  61                warning("bad replace ref name: %s", refname);
  62                return 0;
  63        }
  64
  65        /* Copy sha1 from the read ref */
  66        hashcpy(repl_obj->sha1[1], sha1);
  67
  68        /* Register new object */
  69        if (register_replace_object(repl_obj, 1))
  70                die("duplicate replace ref: %s", refname);
  71
  72        return 0;
  73}
  74
  75static void prepare_replace_object(void)
  76{
  77        static int replace_object_prepared;
  78
  79        if (replace_object_prepared)
  80                return;
  81
  82        for_each_replace_ref(register_replace_ref, NULL);
  83        replace_object_prepared = 1;
  84        if (!replace_object_nr)
  85                read_replace_refs = 0;
  86}
  87
  88/* We allow "recursive" replacement. Only within reason, though */
  89#define MAXREPLACEDEPTH 5
  90
  91const unsigned char *do_lookup_replace_object(const unsigned char *sha1)
  92{
  93        int pos, depth = MAXREPLACEDEPTH;
  94        const unsigned char *cur = sha1;
  95
  96        prepare_replace_object();
  97
  98        /* Try to recursively replace the object */
  99        do {
 100                if (--depth < 0)
 101                        die("replace depth too high for object %s",
 102                            sha1_to_hex(sha1));
 103
 104                pos = replace_object_pos(cur);
 105                if (0 <= pos)
 106                        cur = replace_object[pos]->sha1[1];
 107        } while (0 <= pos);
 108
 109        return cur;
 110}