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convert hashmap comparison functions to oideq()

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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>
This commit is contained in:
Jeff King
2018-08-28 17:22:55 -04:00
committed by Junio C Hamano
parent 67947c34ae
commit cc00e5ce6b
3 changed files with 13 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
patch-ids.c
View File

@ -28,14 +28,14 @@ int commit_patch_id(struct commit *commit, struct diff_options *options,
/*
* 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 "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_cmp(const void *cmpfn_data,
static int patch_id_neq(const void *cmpfn_data,
const void *entry,
const void *entry_or_key,
const void *unused_keydata)
@ -53,7 +53,7 @@ static int patch_id_cmp(const void *cmpfn_data,
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 oidcmp(&a->patch_id, &b->patch_id);
return !oideq(&a->patch_id, &b->patch_id);
}
int init_patch_ids(struct patch_ids *ids)
@ -63,7 +63,7 @@ int init_patch_ids(struct patch_ids *ids)
ids->diffopts.detect_rename = 0;
ids->diffopts.flags.recursive = 1;
diff_setup_done(&ids->diffopts);
hashmap_init(&ids->patches, patch_id_cmp, &ids->diffopts, 256);
hashmap_init(&ids->patches, patch_id_neq, &ids->diffopts, 256);
return 0;
}