git/patch-ids.c
Jeff King cc00e5ce6b convert hashmap comparison functions to oideq()
The comparison functions used for hashmaps don't care about
strict ordering; they only want to compare entries for
equality. Let's use the oideq() function instead, which can
potentially be better optimized. Note that unlike the
previous patches mass-converting calls like "!oidcmp()",
this patch could actually provide an improvement even with
the current implementation. Those comparison functions are
passed around as function pointers, so at compile-time the
compiler cannot realize that the caller (which is in another
file completely) will treat the return value as a boolean.

Note that this does change the return values in quite a
subtle way (it's still an int, but now the sign bit is
irrelevant for ordering). Because of their funny
hashmap-specific signature, it's unlikely that any of these
static functions would be reused for more generic ordering.
But to be double-sure, let's stop using "cmp" in their
names.

Calling them "eq" doesn't quite work either, because the
hashmap convention is actually _inverted_. "0" means "same",
and non-zero means "different". So I've called them "neq" by
convention here.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-29 11:32:49 -07:00

121 lines
3.2 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,
struct object_id *oid, int diff_header_only)
{
if (!patch_id_defined(commit))
return -1;
if (commit->parents)
diff_tree_oid(&commit->parents->item->object.oid,
&commit->object.oid, "", options);
else
diff_root_tree_oid(&commit->object.oid, "", options);
diffcore_std(options);
return diff_flush_patch_id(options, oid, 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 "neq" 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_neq(const void *cmpfn_data,
const void *entry,
const void *entry_or_key,
const void *unused_keydata)
{
/* NEEDSWORK: const correctness? */
struct diff_options *opt = (void *)cmpfn_data;
struct patch_id *a = (void *)entry;
struct patch_id *b = (void *)entry_or_key;
if (is_null_oid(&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_oid(&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 !oideq(&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;
ids->diffopts.flags.recursive = 1;
diff_setup_done(&ids->diffopts);
hashmap_init(&ids->patches, patch_id_neq, &ids->diffopts, 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)
{
struct object_id header_only_patch_id;
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.hash));
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, NULL);
}
struct patch_id *add_commit_patch_id(struct commit *commit,
struct patch_ids *ids)
{
struct patch_id *key;
if (!patch_id_defined(commit))
return NULL;
key = xcalloc(1, sizeof(*key));
if (init_patch_id_entry(key, commit, ids)) {
free(key);
return NULL;
}
hashmap_add(&ids->patches, key);
return key;
}