[PATCH 06/10] fast-export: use a flex array to store anonymized entries

From: Jeff King <peff@peff.net>
To: git@vger.kernel.org
Cc: Eric Sunshine <sunshine@sunshineco.com>,
	Junio C Hamano <gitster@pobox.com>,
	Johannes Schindelin <Johannes.Schindelin@gmx.de>
Subject: [PATCH 06/10] fast-export: use a flex array to store anonymized entries
Date: Tue, 23 Jun 2020 11:24:58 -0400	[thread overview]
Message-ID: <20200623152458.GF1435482@coredump.intra.peff.net> (raw)
In-Reply-To: <20200623152436.GA50925@coredump.intra.peff.net>

Now that we're using a separate keydata struct for hash lookups, we have
more flexibility in how we allocate anonymized_entry structs. Let's push
the "orig" key into a flex member within the struct. That should save us
a few bytes of memory per entry (a pointer plus any malloc overhead),
and may make lookups a little faster (since it's one less pointer to
chase in the comparison function).

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/fast-export.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/builtin/fast-export.c b/builtin/fast-export.c
index 5df2ada47d..99d4a2b404 100644
--- a/builtin/fast-export.c
+++ b/builtin/fast-export.c
@@ -120,8 +120,8 @@ static int has_unshown_parent(struct commit *commit)
 
 struct anonymized_entry {
 	struct hashmap_entry hash;
-	const char *orig;
 	const char *anon;
+	const char orig[FLEX_ARRAY];
 };
 
 struct anonymized_entry_key {
@@ -170,9 +170,8 @@ static const char *anonymize_str(struct hashmap *map,
 	ret = hashmap_get_entry(map, &key, hash, &key);
 
 	if (!ret) {
-		ret = xmalloc(sizeof(*ret));
+		FLEX_ALLOC_MEM(ret, orig, orig, len);
 		hashmap_entry_init(&ret->hash, key.hash.hash);
-		ret->orig = xmemdupz(orig, len);
 		ret->anon = generate(orig, len);
 		hashmap_put(map, &ret->hash);
 	}
-- 
2.27.0.517.gbc32778fa3

