thodg/libgit2

diff --git a/src/cache.c b/src/cache.c
index 424aaae..ec3d9d1 100644
--- a/src/cache.c
+++ b/src/cache.c
@@ -151,16 +151,12 @@ static bool cache_should_store(git_object_t object_type, size_t object_size)
 
 static void *cache_get(git_cache *cache, const git_oid *oid, unsigned int flags)
 {
-	size_t pos;
-	git_cached_obj *entry = NULL;
+	git_cached_obj *entry;
 
 	if (!git_cache__enabled || git_rwlock_rdlock(&cache->lock) < 0)
 		return NULL;
 
-	pos = git_oidmap_lookup_index(cache->map, oid);
-	if (git_oidmap_valid_index(cache->map, pos)) {
-		entry = git_oidmap_value_at(cache->map, pos);
-
+	if ((entry = git_oidmap_get(cache->map, oid)) != NULL) {
 		if (flags && entry->flags != flags) {
 			entry = NULL;
 		} else {
@@ -175,7 +171,7 @@ static void *cache_get(git_cache *cache, const git_oid *oid, unsigned int flags)
 
 static void *cache_store(git_cache *cache, git_cached_obj *entry)
 {
-	size_t pos;
+	git_cached_obj *stored_entry;
 
 	git_cached_obj_incref(entry);
 
@@ -194,10 +190,8 @@ static void *cache_store(git_cache *cache, git_cached_obj *entry)
 	if (git_cache__current_storage.val > git_cache__max_storage)
 		cache_evict_entries(cache);
 
-	pos = git_oidmap_lookup_index(cache->map, &entry->oid);
-
 	/* not found */
-	if (!git_oidmap_valid_index(cache->map, pos)) {
+	if ((stored_entry = git_oidmap_get(cache->map, &entry->oid)) == NULL) {
 		int rval;
 
 		git_oidmap_insert(cache->map, &entry->oid, entry, &rval);
@@ -209,19 +203,18 @@ static void *cache_store(git_cache *cache, git_cached_obj *entry)
 	}
 	/* found */
 	else {
-		git_cached_obj *stored_entry = git_oidmap_value_at(cache->map, pos);
-
 		if (stored_entry->flags == entry->flags) {
 			git_cached_obj_decref(entry);
 			git_cached_obj_incref(stored_entry);
 			entry = stored_entry;
 		} else if (stored_entry->flags == GIT_CACHE_STORE_RAW &&
-			entry->flags == GIT_CACHE_STORE_PARSED) {
+			   entry->flags == GIT_CACHE_STORE_PARSED) {
+			int rval;
+
 			git_cached_obj_decref(stored_entry);
 			git_cached_obj_incref(entry);
 
-			git_oidmap_set_key_at(cache->map, pos, &entry->oid);
-			git_oidmap_set_value_at(cache->map, pos, entry);
+			git_oidmap_insert(cache->map, &entry->oid, entry, &rval);
 		} else {
 			/* NO OP */
 		}
diff --git a/src/describe.c b/src/describe.c
index 2cfa75f..62d8860 100644
--- a/src/describe.c
+++ b/src/describe.c
@@ -36,12 +36,7 @@ struct commit_name {
 
 static void *oidmap_value_bykey(git_oidmap *map, const git_oid *key)
 {
-	size_t pos = git_oidmap_lookup_index(map, key);
-
-	if (!git_oidmap_valid_index(map, pos))
-		return NULL;
-
-	return git_oidmap_value_at(map, pos);
+	return git_oidmap_get(map, key);
 }
 
 static struct commit_name *find_commit_name(
diff --git a/src/merge.c b/src/merge.c
index 22df380..b8bb194 100644
--- a/src/merge.c
+++ b/src/merge.c
@@ -1104,14 +1104,13 @@ static void deletes_by_oid_free(git_oidmap *map) {
 	git_oidmap_free(map);
 }
 
-static int deletes_by_oid_enqueue(git_oidmap *map, git_pool* pool, const git_oid *id, size_t idx) {
-	size_t pos;
+static int deletes_by_oid_enqueue(git_oidmap *map, git_pool* pool, const git_oid *id, size_t idx)
+{
 	deletes_by_oid_queue *queue;
 	size_t *array_entry;
 	int error;
 
-	pos = git_oidmap_lookup_index(map, id);
-	if (!git_oidmap_valid_index(map, pos)) {
+	if ((queue = git_oidmap_get(map, id)) == NULL) {
 		queue = git_pool_malloc(pool, sizeof(deletes_by_oid_queue));
 		GIT_ERROR_CHECK_ALLOC(queue);
 
@@ -1123,7 +1122,6 @@ static int deletes_by_oid_enqueue(git_oidmap *map, git_pool* pool, const git_oid
 		if (error < 0)
 			return -1;
 	} else {
-		queue = git_oidmap_value_at(map, pos);
 		array_entry = git_array_alloc(queue->arr);
 		GIT_ERROR_CHECK_ALLOC(array_entry);
 		*array_entry = idx;
@@ -1132,18 +1130,14 @@ static int deletes_by_oid_enqueue(git_oidmap *map, git_pool* pool, const git_oid
 	return 0;
 }
 
-static int deletes_by_oid_dequeue(size_t *idx, git_oidmap *map, const git_oid *id) {
-	size_t pos;
+static int deletes_by_oid_dequeue(size_t *idx, git_oidmap *map, const git_oid *id)
+{
 	deletes_by_oid_queue *queue;
 	size_t *array_entry;
 
-	pos = git_oidmap_lookup_index(map, id);
-
-	if (!git_oidmap_valid_index(map, pos))
+	if ((queue = git_oidmap_get(map, id)) == NULL)
 		return GIT_ENOTFOUND;
 
-	queue = git_oidmap_value_at(map, pos);
-
 	if (queue->next_pos == 0) {
 		*idx = queue->first_entry;
 	} else {
diff --git a/src/odb_mempack.c b/src/odb_mempack.c
index c68e593..e66f2e9 100644
--- a/src/odb_mempack.c
+++ b/src/odb_mempack.c
@@ -79,15 +79,11 @@ static int impl__exists(git_odb_backend *backend, const git_oid *oid)
 static int impl__read(void **buffer_p, size_t *len_p, git_object_t *type_p, git_odb_backend *backend, const git_oid *oid)
 {
 	struct memory_packer_db *db = (struct memory_packer_db *)backend;
-	struct memobject *obj = NULL;
-	size_t pos;
+	struct memobject *obj;
 
-	pos = git_oidmap_lookup_index(db->objects, oid);
-	if (!git_oidmap_valid_index(db->objects, pos))
+	if ((obj = git_oidmap_get(db->objects, oid)) == NULL)
 		return GIT_ENOTFOUND;
 
-	obj = git_oidmap_value_at(db->objects, pos);
-
 	*len_p = obj->len;
 	*type_p = obj->type;
 	*buffer_p = git__malloc(obj->len);
@@ -100,15 +96,11 @@ static int impl__read(void **buffer_p, size_t *len_p, git_object_t *type_p, git_
 static int impl__read_header(size_t *len_p, git_object_t *type_p, git_odb_backend *backend, const git_oid *oid)
 {
 	struct memory_packer_db *db = (struct memory_packer_db *)backend;
-	struct memobject *obj = NULL;
-	size_t pos;
+	struct memobject *obj;
 
-	pos = git_oidmap_lookup_index(db->objects, oid);
-	if (!git_oidmap_valid_index(db->objects, pos))
+	if ((obj = git_oidmap_get(db->objects, oid)) == NULL)
 		return GIT_ENOTFOUND;
 
-	obj = git_oidmap_value_at(db->objects, pos);
-
 	*len_p = obj->len;
 	*type_p = obj->type;
 	return 0;
diff --git a/src/oidmap.c b/src/oidmap.c
index 6b21807..1e2b812 100644
--- a/src/oidmap.c
+++ b/src/oidmap.c
@@ -48,6 +48,15 @@ size_t git_oidmap_size(git_oidmap *map)
 	return kh_size(map);
 }
 
+void *git_oidmap_get(git_oidmap *map, const git_oid *key)
+{
+	size_t idx = git_oidmap_lookup_index(map, key);
+	if (!git_oidmap_valid_index(map, idx) ||
+	    !git_oidmap_has_data(map, idx))
+		return NULL;
+	return kh_val(map, idx);
+}
+
 size_t git_oidmap_lookup_index(git_oidmap *map, const git_oid *key)
 {
 	return kh_get(oid, map, key);
diff --git a/src/oidmap.h b/src/oidmap.h
index c44f722..799fec4 100644
--- a/src/oidmap.h
+++ b/src/oidmap.h
@@ -52,6 +52,15 @@ void git_oidmap_clear(git_oidmap *map);
  */
 size_t git_oidmap_size(git_oidmap *map);
 
+/**
+ * Return value associated with the given key.
+ *
+ * @param map map to search key in
+ * @param key key to search for
+ * @return value associated with the given key or NULL if the key was not found
+ */
+void *git_oidmap_get(git_oidmap *map, const git_oid *key);
+
 size_t git_oidmap_lookup_index(git_oidmap *map, const git_oid *key);
 int git_oidmap_valid_index(git_oidmap *map, size_t idx);
 
diff --git a/src/pack-objects.c b/src/pack-objects.c
index 4ccc84d..094317a 100644
--- a/src/pack-objects.c
+++ b/src/pack-objects.c
@@ -512,15 +512,12 @@ static int cb_tag_foreach(const char *name, git_oid *oid, void *data)
 {
 	git_packbuilder *pb = data;
 	git_pobject *po;
-	size_t pos;
 
 	GIT_UNUSED(name);
 
-	pos = git_oidmap_lookup_index(pb->object_ix, oid);
-	if (!git_oidmap_valid_index(pb->object_ix, pos))
+	if ((po = git_oidmap_get(pb->object_ix, oid)) == NULL)
 		return 0;
 
-	po = git_oidmap_value_at(pb->object_ix, pos);
 	po->tagged = 1;
 
 	/* TODO: peel objects */
@@ -1537,14 +1534,10 @@ static int lookup_walk_object(struct walk_object **out, git_packbuilder *pb, con
 
 static int retrieve_object(struct walk_object **out, git_packbuilder *pb, const git_oid *id)
 {
-	int error;
-	size_t pos;
 	struct walk_object *obj;
+	int error;
 
-	pos = git_oidmap_lookup_index(pb->walk_objects, id);
-	if (git_oidmap_valid_index(pb->walk_objects, pos)) {
-		obj = git_oidmap_value_at(pb->walk_objects, pos);
-	} else {
+	if ((obj = git_oidmap_get(pb->walk_objects, id)) == NULL) {
 		if ((error = lookup_walk_object(&obj, pb, id)) < 0)
 			return error;
 
diff --git a/src/pack.c b/src/pack.c
index 88af6af..650d203 100644
--- a/src/pack.c
+++ b/src/pack.c
@@ -957,14 +957,13 @@ git_off_t get_delta_base(
 	} else if (type == GIT_OBJECT_REF_DELTA) {
 		/* If we have the cooperative cache, search in it first */
 		if (p->has_cache) {
+			struct git_pack_entry *entry;
 			git_oid oid;
-			size_t k;
 
 			git_oid_fromraw(&oid, base_info);
-			k = git_oidmap_lookup_index(p->idx_cache, &oid);
-			if (git_oidmap_valid_index(p->idx_cache, k)) {
+			if ((entry = git_oidmap_get(p->idx_cache, &oid)) != NULL) {
 				*curpos += 20;
-				return ((struct git_pack_entry *)git_oidmap_value_at(p->idx_cache, k))->offset;
+				return entry->offset;
 			} else {
 				/* If we're building an index, don't try to find the pack
 				 * entry; we just haven't seen it yet.  We'll make
diff --git a/src/revwalk.c b/src/revwalk.c
index b28c341..a052a64 100644
--- a/src/revwalk.c
+++ b/src/revwalk.c
@@ -25,9 +25,8 @@ git_commit_list_node *git_revwalk__commit_lookup(
 	int ret;
 
 	/* lookup and reserve space if not already present */
-	pos = git_oidmap_lookup_index(walk->commits, oid);
-	if (git_oidmap_valid_index(walk->commits, pos))
-		return git_oidmap_value_at(walk->commits, pos);
+	if ((commit = git_oidmap_get(walk->commits, oid)) != NULL)
+		return commit;
 
 	commit = git_commit_list_alloc_node(walk);
 	if (commit == NULL)
diff --git a/tests/core/oidmap.c b/tests/core/oidmap.c
index 519b587..0e66b72 100644
--- a/tests/core/oidmap.c
+++ b/tests/core/oidmap.c
@@ -104,3 +104,81 @@ void test_core_oidmap__hash_collision(void)
 
 	git_oidmap_free(map);
 }
+
+void test_core_oidmap__get_succeeds_with_existing_keys(void)
+{
+	git_oidmap *map;
+	oidmap_item items[NITEMS];
+	uint32_t i, j;
+
+	for (i = 0; i < NITEMS; ++i) {
+		uint32_t segment = i / 8;
+		int modi = i - (segment * 8);
+
+		items[i].extra = i;
+
+		for (j = 0; j < GIT_OID_RAWSZ / 4; ++j) {
+			items[i].oid.id[j * 4    ] = (unsigned char)modi;
+			items[i].oid.id[j * 4 + 1] = (unsigned char)(modi >> 8);
+			items[i].oid.id[j * 4 + 2] = (unsigned char)(modi >> 16);
+			items[i].oid.id[j * 4 + 3] = (unsigned char)(modi >> 24);
+		}
+
+		items[i].oid.id[ 8] = (unsigned char)i;
+		items[i].oid.id[ 9] = (unsigned char)(i >> 8);
+		items[i].oid.id[10] = (unsigned char)(i >> 16);
+		items[i].oid.id[11] = (unsigned char)(i >> 24);
+	}
+
+	cl_git_pass(git_oidmap_new(&map));
+
+	for (i = 0; i < NITEMS; ++i) {
+		int ret;
+		git_oidmap_insert(map, &items[i].oid, &items[i], &ret);
+		cl_assert(ret == 1);
+	}
+
+	for (i = 0; i < NITEMS; ++i)
+		cl_assert_equal_p(git_oidmap_get(map, &items[i].oid), &items[i]);
+
+	git_oidmap_free(map);
+}
+
+void test_core_oidmap__get_fails_with_nonexisting_key(void)
+{
+	git_oidmap *map;
+	oidmap_item items[NITEMS];
+	uint32_t i, j;
+
+	for (i = 0; i < NITEMS; ++i) {
+		uint32_t segment = i / 8;
+		int modi = i - (segment * 8);
+
+		items[i].extra = i;
+
+		for (j = 0; j < GIT_OID_RAWSZ / 4; ++j) {
+			items[i].oid.id[j * 4    ] = (unsigned char)modi;
+			items[i].oid.id[j * 4 + 1] = (unsigned char)(modi >> 8);
+			items[i].oid.id[j * 4 + 2] = (unsigned char)(modi >> 16);
+			items[i].oid.id[j * 4 + 3] = (unsigned char)(modi >> 24);
+		}
+
+		items[i].oid.id[ 8] = (unsigned char)i;
+		items[i].oid.id[ 9] = (unsigned char)(i >> 8);
+		items[i].oid.id[10] = (unsigned char)(i >> 16);
+		items[i].oid.id[11] = (unsigned char)(i >> 24);
+	}
+
+	cl_git_pass(git_oidmap_new(&map));
+
+	/* Do _not_ add last OID to verify that we cannot look it up */
+	for (i = 0; i < NITEMS - 1; ++i) {
+		int ret;
+		git_oidmap_insert(map, &items[i].oid, &items[i], &ret);
+		cl_assert(ret == 1);
+	}
+
+	cl_assert_equal_p(git_oidmap_get(map, &items[NITEMS - 1].oid), NULL);
+
+	git_oidmap_free(map);
+}