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#include "cache.h"
#include "sha1-lookup.h"
#include "refs.h"
#include "commit.h"
/*
* An array of replacements. The array is kept sorted by the original
* sha1.
*/
static struct replace_object {
unsigned char original[20];
unsigned char replacement[20];
} **replace_object;
static int replace_object_alloc, replace_object_nr;
static const unsigned char *replace_sha1_access(size_t index, void *table)
{
struct replace_object **replace = table;
return replace[index]->original;
}
static int replace_object_pos(const unsigned char *sha1)
{
return sha1_pos(sha1, replace_object, replace_object_nr,
replace_sha1_access);
}
static int register_replace_object(struct replace_object *replace,
int ignore_dups)
{
int pos = replace_object_pos(replace->original);
if (0 <= pos) {
if (ignore_dups)
free(replace);
else {
free(replace_object[pos]);
replace_object[pos] = replace;
}
return 1;
}
pos = -pos - 1;
if (replace_object_alloc <= ++replace_object_nr) {
replace_object_alloc = alloc_nr(replace_object_alloc);
replace_object = xrealloc(replace_object,
sizeof(*replace_object) *
replace_object_alloc);
}
if (pos < replace_object_nr)
memmove(replace_object + pos + 1,
replace_object + pos,
(replace_object_nr - pos - 1) *
sizeof(*replace_object));
replace_object[pos] = replace;
return 0;
}
static int register_replace_ref(const char *refname,
const unsigned char *sha1,
int flag, void *cb_data)
{
/* Get sha1 from refname */
const char *slash = strrchr(refname, '/');
const char *hash = slash ? slash + 1 : refname;
struct replace_object *repl_obj = xmalloc(sizeof(*repl_obj));
if (strlen(hash) != 40 || get_sha1_hex(hash, repl_obj->original)) {
free(repl_obj);
warning("bad replace ref name: %s", refname);
return 0;
}
/* Copy sha1 from the read ref */
hashcpy(repl_obj->replacement, sha1);
/* Register new object */
if (register_replace_object(repl_obj, 1))
die("duplicate replace ref: %s", refname);
return 0;
}
static void prepare_replace_object(void)
{
static int replace_object_prepared;
if (replace_object_prepared)
return;
for_each_replace_ref(register_replace_ref, NULL);
replace_object_prepared = 1;
if (!replace_object_nr)
check_replace_refs = 0;
}
/* We allow "recursive" replacement. Only within reason, though */
#define MAXREPLACEDEPTH 5
/*
* If a replacement for object sha1 has been set up, return the
* replacement object's name (replaced recursively, if necessary).
* The return value is either sha1 or a pointer to a
* permanently-allocated value. This function always respects replace
* references, regardless of the value of check_replace_refs.
*/
const unsigned char *do_lookup_replace_object(const unsigned char *sha1)
{
int pos, depth = MAXREPLACEDEPTH;
const unsigned char *cur = sha1;
prepare_replace_object();
/* Try to recursively replace the object */
do {
if (--depth < 0)
die("replace depth too high for object %s",
sha1_to_hex(sha1));
pos = replace_object_pos(cur);
if (0 <= pos)
cur = replace_object[pos]->replacement;
} while (0 <= pos);
return cur;
}
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