Improve performance of age limit trimming

CHANGELOG.md

@@ -5,6 +5,7 @@
 - [performance] Reduce locking churn in cleanup methods. [#212](https://github.com/pinterest/PINCache/pull/212)
 - [fix] Don't set file protection unless requested. [#220](https://github.com/pinterest/PINCache/pull/220)
 - [new] Add ability to set an object level TTL: [#209](https://github.com/pinterest/PINCache/pull/209)
+- [performance] Improve performance of age limit trimming: [#224](https://github.com/pinterest/PINCache/pull/224)
 
 ## 3.0.1 -- Beta 6
 - [fix] Add some sane limits to the disk cache: [#201]https://github.com/pinterest/PINCache/pull/201

Source/PINDiskCache.m

@@ -785,13 +785,24 @@ - (void)trimToAgeLimitRecursively
         return;
 
     NSDate *date = [[NSDate alloc] initWithTimeIntervalSinceNow:-ageLimit];
-    [self trimDiskToDate:date];
+    [self trimToDateAsync:date completion:nil];
 
     dispatch_time_t time = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(ageLimit * NSEC_PER_SEC));
     dispatch_after(time, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^(void) {
-        [self.operationQueue scheduleOperation:^{
-            [self trimToAgeLimitRecursively];
-        } withPriority:PINOperationQueuePriorityLow];
+        // Ensure that ageLimit is the same as when we were scheduled, otherwise, we've been
+        // rescheduled (another dispatch_after was issued) and should cancel.
+        BOOL shouldReschedule = YES;
+        [self lock];
+            if (ageLimit != self->_ageLimit) {
+                shouldReschedule = NO;
+            }
+        [self unlock];
+
+        if (shouldReschedule) {
+            [self.operationQueue scheduleOperation:^{
+                [self trimToAgeLimitRecursively];
+            } withPriority:PINOperationQueuePriorityLow];
+        }
     });
 }
 
@@ -1506,7 +1517,9 @@ - (void)setAgeLimit:(NSTimeInterval)ageLimit
             self->_ageLimit = ageLimit;
         [self unlock];
 
-        [self trimToAgeLimitRecursively];
+        [self.operationQueue scheduleOperation:^{
+            [self trimToAgeLimitRecursively];
+        } withPriority:PINOperationQueuePriorityLow];
     } withPriority:PINOperationQueuePriorityHigh];
 }
 

Source/PINMemoryCache.m

@@ -298,9 +298,20 @@ - (void)trimToAgeLimitRecursively
 
     dispatch_time_t time = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(ageLimit * NSEC_PER_SEC));
     dispatch_after(time, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^(void){
-        [self.operationQueue scheduleOperation:^{
-            [self trimToAgeLimitRecursively];
-        } withPriority:PINOperationQueuePriorityHigh];
+        // Ensure that ageLimit is the same as when we were scheduled, otherwise, we've been
+        // rescheduled (another dispatch_after was issued) and should cancel.
+        BOOL shouldReschedule = YES;
+        [self lock];
+            if (ageLimit != self->_ageLimit) {
+                shouldReschedule = NO;
+            }
+        [self unlock];
+
+        if (shouldReschedule) {
+            [self.operationQueue scheduleOperation:^{
+                [self trimToAgeLimitRecursively];
+            } withPriority:PINOperationQueuePriorityHigh];
+        }
     });
 }