Disable text kit lock (#1910)

* Add experiment to disable global textkit lock * Forgot the bang
TextureGroup · Sep 17, 2020 · d7f58a5 · d7f58a5
1 parent 45c0f19
commit d7f58a5
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Showing 3 changed files with 14 additions and 8 deletions.
diff --git a/Source/ASExperimentalFeatures.h b/Source/ASExperimentalFeatures.h
@@ -28,6 +28,7 @@ typedef NS_OPTIONS(NSUInteger, ASExperimentalFeatures) {
   ASExperimentalDispatchApply = 1 << 7,                                     // exp_dispatch_apply
   ASExperimentalDrawingGlobal = 1 << 8,                                     // exp_drawing_global
   ASExperimentalOptimizeDataControllerPipeline = 1 << 9,                    // exp_optimize_data_controller_pipeline
+  ASExperimentalDisableGlobalTextkitLock = 1 << 10,                         // exp_disable_global_textkit_lock
   ASExperimentalFeatureAll = 0xFFFFFFFF
 };
 

diff --git a/Source/ASExperimentalFeatures.mm b/Source/ASExperimentalFeatures.mm
@@ -21,7 +21,8 @@
                                       @"exp_did_enter_preload_skip_asm_layout",
                                       @"exp_dispatch_apply",
                                       @"exp_drawing_global",
-                                      @"exp_optimize_data_controller_pipeline"]));
+                                      @"exp_optimize_data_controller_pipeline",
+                                    @"exp_disable_global_textkit_lock"]));
   if (flags == ASExperimentalFeatureAll) {
     return allNames;
   }

diff --git a/Source/TextKit/ASTextKitContext.mm b/Source/TextKit/ASTextKitContext.mm
@@ -35,12 +35,16 @@ - (instancetype)initWithAttributedString:(NSAttributedString *)attributedString
   if (self = [super init]) {
     static AS::Mutex *mutex = NULL;
     static dispatch_once_t onceToken;
-    // Concurrently initialising TextKit components crashes (rdar://18448377) so we use a global lock.
-    dispatch_once(&onceToken, ^{
-        mutex = new AS::Mutex();
-    });
-    if (mutex != NULL) {
-      mutex->lock();
+
+    BOOL useGlobalTextKitLock = !ASActivateExperimentalFeature(ASExperimentalDisableGlobalTextkitLock);
+    if (useGlobalTextKitLock) {
+        // Concurrently initialising TextKit components crashes (rdar://18448377) so we use a global lock.
+        dispatch_once(&onceToken, ^{
+            mutex = new AS::Mutex();
+        });
+        if (mutex != NULL) {
+          mutex->lock();
+        }
     }
 
     __instanceLock__ = std::make_shared<AS::Mutex>();
@@ -76,7 +80,7 @@ - (instancetype)initWithAttributedString:(NSAttributedString *)attributedString
     _textContainer.exclusionPaths = exclusionPaths;
     [_layoutManager addTextContainer:_textContainer];
 
-    if (mutex != NULL) {
+    if (useGlobalTextKitLock && mutex != NULL) {
       mutex->unlock();
     }
   }