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        if (replace_object_alloc <= ++replace_object_nr) {
  45                replace_object_alloc = alloc_nr(replace_object_alloc);
  46                replace_object = xrealloc(replace_object,
  47                                          sizeof(*replace_object) *
  48                                          replace_object_alloc);
  49        }
  50        if (pos < replace_object_nr)
  51                memmove(replace_object + pos + 1,
  52                        replace_object + pos,
  53                        (replace_object_nr - pos - 1) *
  54                        sizeof(*replace_object));
  55        replace_object[pos] = replace;
  56        return 0;
  57}
  58
  59static int register_replace_ref(const char *refname,
  60                                const unsigned char *sha1,
  61                                int flag, void *cb_data)
  62{
  63        /* Get sha1 from refname */
  64        const char *slash = strrchr(refname, '/');
  65        const char *hash = slash ? slash + 1 : refname;
  66        struct replace_object *repl_obj = xmalloc(sizeof(*repl_obj));
  67
  68        if (strlen(hash) != 40 || get_sha1_hex(hash, repl_obj->original)) {
  69                free(repl_obj);
  70                warning("bad replace ref name: %s", refname);
  71                return 0;
  72        }
  73
  74        /* Copy sha1 from the read ref */
  75        hashcpy(repl_obj->replacement, sha1);
  76
  77        /* Register new object */
  78        if (register_replace_object(repl_obj, 1))
  79                die("duplicate replace ref: %s", refname);
  80
  81        return 0;
  82}
  83
  84static void prepare_replace_object(void)
  85{
  86        static int replace_object_prepared;
  87
  88        if (replace_object_prepared)
  89                return;
  90
  91        for_each_replace_ref(register_replace_ref, NULL);
  92        replace_object_prepared = 1;
  93        if (!replace_object_nr)
  94                read_replace_refs = 0;
  95}
  96
  97/* We allow "recursive" replacement. Only within reason, though */
  98#define MAXREPLACEDEPTH 5
  99
 100const unsigned char *do_lookup_replace_object(const unsigned char *sha1)
 101{
 102        int pos, depth = MAXREPLACEDEPTH;
 103        const unsigned char *cur = sha1;
 104
 105        prepare_replace_object();
 106
 107        /* Try to recursively replace the object */
 108        do {
 109                if (--depth < 0)
 110                        die("replace depth too high for object %s",
 111                            sha1_to_hex(sha1));
 112
 113                pos = replace_object_pos(cur);
 114                if (0 <= pos)
 115                        cur = replace_object[pos]->replacement;
 116        } while (0 <= pos);
 117
 118        return cur;
 119}