[PATCH 3/3] salad: fix heap reserve() behaviour

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

Reserve() function by definition should ensure that there is
enough space to store something. But heap reserve() always just
increases the capacity twice. Even if there was already enough
memory. Check for not necessary realloc was done out of this
function. This was wrong. The commit makes reserve() be real
reserve().

The commit is motivated not by pursue of justice, but by
forthcoming usage of reserve() in SWIM module code.
---
 src/lib/salad/heap.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/lib/salad/heap.h b/src/lib/salad/heap.h
index f267de3f1..31750216a 100644
--- a/src/lib/salad/heap.h
+++ b/src/lib/salad/heap.h
@@ -382,6 +382,8 @@ HEAP(sift_down)(heap_t *heap, struct heap_node *node)
 static inline int
 HEAP(reserve)(heap_t *heap)
 {
+	if (heap->capacity > heap->size)
+		return 0;
 	heap_off_t capacity = heap->capacity == 0 ? HEAP_INITIAL_CAPACITY :
 		heap->capacity << 1;
 	void *harr = realloc(heap->harr, sizeof(struct heap_node *) * capacity);
@@ -398,10 +400,8 @@ HEAP(reserve)(heap_t *heap)
 static inline int
 HEAP(insert)(heap_t *heap, heap_value_t *value)
 {
-	if (heap->size + 1 > heap->capacity) {
-		if (HEAP(reserve)(heap))
-			return -1;
-	}
+	if (HEAP(reserve)(heap))
+		return -1;
 	struct heap_node *node = value_to_node(value);
 	heap->harr[heap->size] = node;
 	HEAP(update_link)(heap, heap->size++);
-- 
2.17.2 (Apple Git-113)