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git/patch-ids.c
brian m. carlson cd02599c48 Convert GIT_SHA1_RAWSZ used for allocation to GIT_MAX_RAWSZ
Since we will likely be introducing a new hash function at some point,
and that hash function might be longer than 20 bytes, use the constant
GIT_MAX_RAWSZ, which is designed to be suitable for allocations, instead
of GIT_SHA1_RAWSZ.  This will ease the transition down the line by
distinguishing between places where we need to allocate memory suitable
for the largest hash from those where we need to handle the current
hash.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-26 22:08:21 -07:00

114 lines
3.1 KiB
C

#include "cache.h"
#include "diff.h"
#include "commit.h"
#include "sha1-lookup.h"
#include "patch-ids.h"
static int patch_id_defined(struct commit *commit)
{
/* must be 0 or 1 parents */
return !commit->parents || !commit->parents->next;
}
int commit_patch_id(struct commit *commit, struct diff_options *options,
unsigned char *sha1, int diff_header_only)
{
if (!patch_id_defined(commit))
return -1;
if (commit->parents)
diff_tree_sha1(commit->parents->item->object.oid.hash,
commit->object.oid.hash, "", options);
else
diff_root_tree_sha1(commit->object.oid.hash, "", options);
diffcore_std(options);
return diff_flush_patch_id(options, sha1, diff_header_only);
}
/*
* When we cannot load the full patch-id for both commits for whatever
* reason, the function returns -1 (i.e. return error(...)). Despite
* the "cmp" in the name of this function, the caller only cares about
* the return value being zero (a and b are equivalent) or non-zero (a
* and b are different), and returning non-zero would keep both in the
* result, even if they actually were equivalent, in order to err on
* the side of safety. The actual value being negative does not have
* any significance; only that it is non-zero matters.
*/
static int patch_id_cmp(struct patch_id *a,
struct patch_id *b,
struct diff_options *opt)
{
if (is_null_sha1(a->patch_id) &&
commit_patch_id(a->commit, opt, a->patch_id, 0))
return error("Could not get patch ID for %s",
oid_to_hex(&a->commit->object.oid));
if (is_null_sha1(b->patch_id) &&
commit_patch_id(b->commit, opt, b->patch_id, 0))
return error("Could not get patch ID for %s",
oid_to_hex(&b->commit->object.oid));
return hashcmp(a->patch_id, b->patch_id);
}
int init_patch_ids(struct patch_ids *ids)
{
memset(ids, 0, sizeof(*ids));
diff_setup(&ids->diffopts);
ids->diffopts.detect_rename = 0;
DIFF_OPT_SET(&ids->diffopts, RECURSIVE);
diff_setup_done(&ids->diffopts);
hashmap_init(&ids->patches, (hashmap_cmp_fn)patch_id_cmp, 256);
return 0;
}
int free_patch_ids(struct patch_ids *ids)
{
hashmap_free(&ids->patches, 1);
return 0;
}
static int init_patch_id_entry(struct patch_id *patch,
struct commit *commit,
struct patch_ids *ids)
{
unsigned char header_only_patch_id[GIT_MAX_RAWSZ];
patch->commit = commit;
if (commit_patch_id(commit, &ids->diffopts, header_only_patch_id, 1))
return -1;
hashmap_entry_init(patch, sha1hash(header_only_patch_id));
return 0;
}
struct patch_id *has_commit_patch_id(struct commit *commit,
struct patch_ids *ids)
{
struct patch_id patch;
if (!patch_id_defined(commit))
return NULL;
memset(&patch, 0, sizeof(patch));
if (init_patch_id_entry(&patch, commit, ids))
return NULL;
return hashmap_get(&ids->patches, &patch, &ids->diffopts);
}
struct patch_id *add_commit_patch_id(struct commit *commit,
struct patch_ids *ids)
{
struct patch_id *key = xcalloc(1, sizeof(*key));
if (!patch_id_defined(commit))
return NULL;
if (init_patch_id_entry(key, commit, ids)) {
free(key);
return NULL;
}
hashmap_add(&ids->patches, key);
return key;
}