Fix potential LRU cache size issue.

Signed-off-by: kuba-- <kuba@sourced.tech>

1 files changed, 13 insertions, 11 deletions

diff --git a/plumbing/cache/object_lru.go b/plumbing/cache/object_lru.go
index 0494539..31c0202 100644
--- a/plumbing/cache/object_lru.go
+++ b/plumbing/cache/object_lru.go
@@ -42,20 +42,26 @@ func (c *ObjectLRU) Put(obj plumbing.EncodedObject) {
 		c.ll = list.New()
 	}
 
+	objSize := FileSize(obj.Size())
 	key := obj.Hash()
 	if ee, ok := c.cache[key]; ok {
+		oldObj := ee.Value.(plumbing.EncodedObject)
+		// in this case objSize is a delta: new size - old size
+		objSize -= FileSize(oldObj.Size())
+
 		c.ll.MoveToFront(ee)
 		ee.Value = obj
-		return
-	}
-
-	objSize := FileSize(obj.Size())
+	} else {
+		if objSize > c.MaxSize {
+			return
+		}
 
-	if objSize > c.MaxSize {
-		return
+		ee := c.ll.PushFront(obj)
+		c.cache[key] = ee
 	}
 
-	for c.actualSize+objSize > c.MaxSize {
+	c.actualSize += objSize
+	for c.actualSize > c.MaxSize {
 		last := c.ll.Back()
 		lastObj := last.Value.(plumbing.EncodedObject)
 		lastSize := FileSize(lastObj.Size())
@@ -64,10 +70,6 @@ func (c *ObjectLRU) Put(obj plumbing.EncodedObject) {
 		delete(c.cache, lastObj.Hash())
 		c.actualSize -= lastSize
 	}
-
-	ee := c.ll.PushFront(obj)
-	c.cache[key] = ee
-	c.actualSize += objSize
 }
 
 // Get returns an object by its hash. It marks the object as used. If the object