From 862e730ec1c13f28bfb7c8c9ecb39bcc92dd0922 Mon Sep 17 00:00:00 2001 From: Junio C Hamano Date: Thu, 14 May 2015 15:25:52 -0700 Subject: commit-slab: introduce slabname##_peek() function There is no API to ask "Does this commit have associated data in slab?". If an application wants to (1) parse just a few commits at the beginning of a process, (2) store data for only these commits, and then (3) start processing many commits, taking into account the data stored (for a few of them) in the slab, the application would use slabname##_at() to allocate a space to store data in (2), but there is no API other than slabname##_at() to use in step (3). This allocates and wastes new space for these commits the caller is only interested in checking if they have data stored in step (2). Introduce slabname##_peek(), which is similar to slabname##_at() but returns NULL when there is no data already associated to it in such a use case. Helped-by: Jeff King Signed-off-by: Junio C Hamano --- commit.c | 28 ++++++++++++++++++++-------- 1 file changed, 20 insertions(+), 8 deletions(-) (limited to 'commit.c') diff --git a/commit.c b/commit.c index 65179f96ee..5fb9496520 100644 --- a/commit.c +++ b/commit.c @@ -244,7 +244,12 @@ void set_commit_buffer(struct commit *commit, void *buffer, unsigned long size) const void *get_cached_commit_buffer(const struct commit *commit, unsigned long *sizep) { - struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit); + struct commit_buffer *v = buffer_slab_peek(&buffer_slab, commit); + if (!v) { + if (sizep) + *sizep = 0; + return NULL; + } if (sizep) *sizep = v->size; return v->buffer; @@ -271,24 +276,31 @@ const void *get_commit_buffer(const struct commit *commit, unsigned long *sizep) void unuse_commit_buffer(const struct commit *commit, const void *buffer) { - struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit); - if (v->buffer != buffer) + struct commit_buffer *v = buffer_slab_peek(&buffer_slab, commit); + if (!(v && v->buffer == buffer)) free((void *)buffer); } void free_commit_buffer(struct commit *commit) { - struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit); - free(v->buffer); - v->buffer = NULL; - v->size = 0; + struct commit_buffer *v = buffer_slab_peek(&buffer_slab, commit); + if (v) { + free(v->buffer); + v->buffer = NULL; + v->size = 0; + } } const void *detach_commit_buffer(struct commit *commit, unsigned long *sizep) { - struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit); + struct commit_buffer *v = buffer_slab_peek(&buffer_slab, commit); void *ret; + if (!v) { + if (sizep) + *sizep = 0; + return NULL; + } ret = v->buffer; if (sizep) *sizep = v->size; -- cgit v1.2.3