Make ASBatchContext lock-free (TextureGroup#854)

mikezucc · Mar 26, 2018 · 063194c · 063194c
1 parent 27fac9f
commit 063194c
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Showing 2 changed files with 14 additions and 24 deletions.
diff --git a/AsyncDisplayKit.xcodeproj/project.pbxproj b/AsyncDisplayKit.xcodeproj/project.pbxproj
@@ -264,7 +264,7 @@
 		B35062131B010EFD0018CF92 /* ASBasicImageDownloader.h in Headers */ = {isa = PBXBuildFile; fileRef = 054963471A1EA066000F8E56 /* ASBasicImageDownloader.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		B35062141B010EFD0018CF92 /* ASBasicImageDownloader.mm in Sources */ = {isa = PBXBuildFile; fileRef = 054963481A1EA066000F8E56 /* ASBasicImageDownloader.mm */; };
 		B35062151B010EFD0018CF92 /* ASBatchContext.h in Headers */ = {isa = PBXBuildFile; fileRef = 299DA1A71A828D2900162D41 /* ASBatchContext.h */; settings = {ATTRIBUTES = (Public, ); }; };
-		B35062161B010EFD0018CF92 /* ASBatchContext.mm in Sources */ = {isa = PBXBuildFile; fileRef = 299DA1A81A828D2900162D41 /* ASBatchContext.mm */; };
+		B35062161B010EFD0018CF92 /* ASBatchContext.m in Sources */ = {isa = PBXBuildFile; fileRef = 299DA1A81A828D2900162D41 /* ASBatchContext.m */; };
 		B35062171B010EFD0018CF92 /* ASDataController.h in Headers */ = {isa = PBXBuildFile; fileRef = 464052191A3F83C40061C0BA /* ASDataController.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		B35062181B010EFD0018CF92 /* ASDataController.mm in Sources */ = {isa = PBXBuildFile; fileRef = 4640521A1A3F83C40061C0BA /* ASDataController.mm */; };
 		B350621B1B010EFD0018CF92 /* ASTableLayoutController.h in Headers */ = {isa = PBXBuildFile; fileRef = 4640521B1A3F83C40061C0BA /* ASTableLayoutController.h */; settings = {ATTRIBUTES = (Private, ); }; };
@@ -643,7 +643,7 @@
 		296A0A311A951715005ACEAA /* ASScrollDirection.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASScrollDirection.h; path = Source/Details/ASScrollDirection.h; sourceTree = SOURCE_ROOT; };
 		296A0A341A951ABF005ACEAA /* ASBatchFetchingTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; lineEnding = 0; path = ASBatchFetchingTests.m; sourceTree = "<group>"; xcLanguageSpecificationIdentifier = xcode.lang.objc; };
 		299DA1A71A828D2900162D41 /* ASBatchContext.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASBatchContext.h; sourceTree = "<group>"; };
-		299DA1A81A828D2900162D41 /* ASBatchContext.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASBatchContext.mm; sourceTree = "<group>"; };
+		299DA1A81A828D2900162D41 /* ASBatchContext.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ASBatchContext.m; sourceTree = "<group>"; };
 		29CDC2E11AAE70D000833CA4 /* ASBasicImageDownloaderContextTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; lineEnding = 0; path = ASBasicImageDownloaderContextTests.m; sourceTree = "<group>"; xcLanguageSpecificationIdentifier = xcode.lang.objc; };
 		3917EBD21E9C2FC400D04A01 /* _ASCollectionReusableView.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = _ASCollectionReusableView.h; sourceTree = "<group>"; };
 		3917EBD31E9C2FC400D04A01 /* _ASCollectionReusableView.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = _ASCollectionReusableView.m; sourceTree = "<group>"; };
@@ -1333,7 +1333,7 @@
 				054963471A1EA066000F8E56 /* ASBasicImageDownloader.h */,
 				054963481A1EA066000F8E56 /* ASBasicImageDownloader.mm */,
 				299DA1A71A828D2900162D41 /* ASBatchContext.h */,
-				299DA1A81A828D2900162D41 /* ASBatchContext.mm */,
+				299DA1A81A828D2900162D41 /* ASBatchContext.m */,
 				E5C347B01ECB3D9200EC4BE4 /* ASBatchFetchingDelegate.h */,
 				205F0E1B1B373A2C007741D0 /* ASCollectionViewLayoutController.h */,
 				205F0E1C1B373A2C007741D0 /* ASCollectionViewLayoutController.m */,
@@ -2339,7 +2339,7 @@
 				34EFC7621B701CA400AD841F /* ASBackgroundLayoutSpec.mm in Sources */,
 				DE8BEAC41C2DF3FC00D57C12 /* ASDelegateProxy.m in Sources */,
 				B35062141B010EFD0018CF92 /* ASBasicImageDownloader.mm in Sources */,
-				B35062161B010EFD0018CF92 /* ASBatchContext.mm in Sources */,
+				B35062161B010EFD0018CF92 /* ASBatchContext.m in Sources */,
 				AC47D9421B3B891B00AAEE9D /* ASCellNode.mm in Sources */,
 				E58E9E451E941D74004CFC59 /* ASCollectionLayoutContext.m in Sources */,
 				34EFC7641B701CC600AD841F /* ASCenterLayoutSpec.mm in Sources */,

diff --git a/Source/Details/ASBatchContext.mm → Source/Details/ASBatchContext.m b/Source/Details/ASBatchContext.mm → Source/Details/ASBatchContext.m
@@ -1,5 +1,5 @@
 //
-//  ASBatchContext.mm
+//  ASBatchContext.m
 //  Texture
 //
 //  Copyright (c) 2014-present, Facebook, Inc.  All rights reserved.
@@ -18,62 +18,52 @@
 #import <AsyncDisplayKit/ASBatchContext.h>
 
 #import <AsyncDisplayKit/ASLog.h>
-#import <AsyncDisplayKit/ASThread.h>
+#import <stdatomic.h>
 
 typedef NS_ENUM(NSInteger, ASBatchContextState) {
   ASBatchContextStateFetching,
   ASBatchContextStateCancelled,
   ASBatchContextStateCompleted
 };
 
-@interface ASBatchContext ()
-{
-  ASBatchContextState _state;
-  ASDN::RecursiveMutex __instanceLock__;
+@implementation ASBatchContext {
+  atomic_int _state;
 }
-@end
-
-@implementation ASBatchContext
 
 - (instancetype)init
 {
   if (self = [super init]) {
-    _state = ASBatchContextStateCompleted;
+    _state = ATOMIC_VAR_INIT(ASBatchContextStateCompleted);
   }
   return self;
 }
 
 - (BOOL)isFetching
 {
-  ASDN::MutexLocker l(__instanceLock__);
-  return _state == ASBatchContextStateFetching;
+  return atomic_load(&_state) == ASBatchContextStateFetching;
 }
 
 - (BOOL)batchFetchingWasCancelled
 {
-  ASDN::MutexLocker l(__instanceLock__);
-  return _state == ASBatchContextStateCancelled;
+  return atomic_load(&_state) == ASBatchContextStateCancelled;
 }
 
 - (void)beginBatchFetching
 {
-  ASDN::MutexLocker l(__instanceLock__);
-  _state = ASBatchContextStateFetching;
+  atomic_store(&_state, ASBatchContextStateFetching);
 }
 
 - (void)completeBatchFetching:(BOOL)didComplete
 {
   if (didComplete) {
     as_log_debug(ASCollectionLog(), "Completed batch fetch with context %@", self);
-    ASDN::MutexLocker l(__instanceLock__);
-    _state = ASBatchContextStateCompleted;
+    atomic_store(&_state, ASBatchContextStateCompleted);
   }
 }
 
 - (void)cancelBatchFetching
 {
-  ASDN::MutexLocker l(__instanceLock__);
-  _state = ASBatchContextStateCancelled;
+  atomic_store(&_state, ASBatchContextStateCancelled);
 }
 
 @end