From ab789455fc96440b46c61e8ac9c7722981eb98f8 Mon Sep 17 00:00:00 2001
From: zhongwuzw <zhongwuzw@qq.com>
Date: Wed, 18 Apr 2018 18:25:34 +0800
Subject: [PATCH] Optimize trylock using runLoop to replace usleep

`usleep` function would block the thread, in `RunLoop` way, which can
handle input sources in 10 ms.
---
 YYCache/YYMemoryCache.m | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/YYCache/YYMemoryCache.m b/YYCache/YYMemoryCache.m
index 9042d9b..5e96ba3 100644
--- a/YYCache/YYMemoryCache.m
+++ b/YYCache/YYMemoryCache.m
@@ -176,6 +176,7 @@ @implementation YYMemoryCache {
     pthread_mutex_t _lock;
     _YYLinkedMap *_lru;
     dispatch_queue_t _queue;
+    CFRunLoopSourceRef _noSpinSource;
 }
 
 - (void)_trimRecursively {
@@ -208,6 +209,8 @@ - (void)_trimToCost:(NSUInteger)costLimit {
     pthread_mutex_unlock(&_lock);
     if (finish) return;
     
+    CFRunLoopAddSource(CFRunLoopGetCurrent(), _noSpinSource, kCFRunLoopDefaultMode);
+    
     NSMutableArray *holder = [NSMutableArray new];
     while (!finish) {
         if (pthread_mutex_trylock(&_lock) == 0) {
@@ -219,7 +222,7 @@ - (void)_trimToCost:(NSUInteger)costLimit {
             }
             pthread_mutex_unlock(&_lock);
         } else {
-            usleep(10 * 1000); //10 ms
+            CFRunLoopRunInMode(kCFRunLoopDefaultMode, 0.01, NO); // Give RunLoop 10ms to handle input sources.
         }
     }
     if (holder.count) {
@@ -242,6 +245,8 @@ - (void)_trimToCount:(NSUInteger)countLimit {
     pthread_mutex_unlock(&_lock);
     if (finish) return;
     
+    CFRunLoopAddSource(CFRunLoopGetCurrent(), _noSpinSource, kCFRunLoopDefaultMode);
+    
     NSMutableArray *holder = [NSMutableArray new];
     while (!finish) {
         if (pthread_mutex_trylock(&_lock) == 0) {
@@ -253,7 +258,7 @@ - (void)_trimToCount:(NSUInteger)countLimit {
             }
             pthread_mutex_unlock(&_lock);
         } else {
-            usleep(10 * 1000); //10 ms
+            CFRunLoopRunInMode(kCFRunLoopDefaultMode, 0.01, NO); // Give RunLoop 10ms to handle input sources.
         }
     }
     if (holder.count) {
@@ -277,6 +282,8 @@ - (void)_trimToAge:(NSTimeInterval)ageLimit {
     pthread_mutex_unlock(&_lock);
     if (finish) return;
     
+    CFRunLoopAddSource(CFRunLoopGetCurrent(), _noSpinSource, kCFRunLoopDefaultMode);
+    
     NSMutableArray *holder = [NSMutableArray new];
     while (!finish) {
         if (pthread_mutex_trylock(&_lock) == 0) {
@@ -288,7 +295,7 @@ - (void)_trimToAge:(NSTimeInterval)ageLimit {
             }
             pthread_mutex_unlock(&_lock);
         } else {
-            usleep(10 * 1000); //10 ms
+            CFRunLoopRunInMode(kCFRunLoopDefaultMode, 0.01, NO); // Give RunLoop 10ms to handle input sources.
         }
     }
     if (holder.count) {
@@ -331,6 +338,8 @@ - (instancetype)init {
     _autoTrimInterval = 5.0;
     _shouldRemoveAllObjectsOnMemoryWarning = YES;
     _shouldRemoveAllObjectsWhenEnteringBackground = YES;
+    CFRunLoopSourceContext noSpinCtx = {0, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL};
+    _noSpinSource = CFRunLoopSourceCreate(NULL, 0, &noSpinCtx);
     
     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(_appDidReceiveMemoryWarningNotification) name:UIApplicationDidReceiveMemoryWarningNotification object:nil];
     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(_appDidEnterBackgroundNotification) name:UIApplicationDidEnterBackgroundNotification object:nil];
@@ -344,6 +353,7 @@ - (void)dealloc {
     [[NSNotificationCenter defaultCenter] removeObserver:self name:UIApplicationDidEnterBackgroundNotification object:nil];
     [_lru removeAll];
     pthread_mutex_destroy(&_lock);
+    CFRelease(_noSpinSource);
 }
 
 - (NSUInteger)totalCount {