Add a verbose log for locking operations. Has no effect in production

Source/ASDisplayNode.mm

@@ -310,6 +310,7 @@ - (void)_staticInitialize
 - (void)_initializeInstance
 {
   [self _staticInitialize];
+  __instanceLock__.SetDebugNameWithObject(self);
 
 #if ASEVENTLOG_ENABLE
   _eventLog = [[ASEventLog alloc] initWithObject:self];

Source/Base/ASLog.h

@@ -66,6 +66,9 @@ AS_EXTERN os_log_t ASImageLoadingLog(void);
 #define ASMainThreadDeallocationLogEnabled 0
 AS_EXTERN os_log_t ASMainThreadDeallocationLog(void);
 
+#define ASLockingLogEnabled 0
+AS_EXTERN os_log_t ASLockingLog(void);
+
 /**
  * The activity tracing system changed a lot between iOS 9 and 10.
  * In iOS 10, the system was merged with logging and became much more powerful

Source/Base/ASLog.mm

@@ -46,3 +46,7 @@ os_log_t ASImageLoadingLog() {
 os_log_t ASMainThreadDeallocationLog() {
   return (ASMainThreadDeallocationLogEnabled && ASLoggingIsEnabled()) ? ASCreateOnce(as_log_create("org.TextureGroup.Texture", "MainDealloc")) : OS_LOG_DISABLED;
 }
+
+os_log_t ASLockingLog() {
+  return (ASLockingLogEnabled && ASLoggingIsEnabled()) ? ASCreateOnce(as_log_create("org.TextureGroup.Texture", "Locking")) : OS_LOG_DISABLED;
+}

Source/Details/ASThread.h

@@ -16,6 +16,8 @@
 #import <AsyncDisplayKit/ASAvailability.h>
 #import <AsyncDisplayKit/ASBaseDefines.h>
 #import <AsyncDisplayKit/ASConfigurationInternal.h>
+#import <AsyncDisplayKit/ASLog.h>
+#import <AsyncDisplayKit/ASObjectDescriptionHelpers.h>
 #import <AsyncDisplayKit/ASRecursiveUnfairLock.h>
 
 ASDISPLAYNODE_INLINE AS_WARN_UNUSED_RESULT BOOL ASDisplayNodeThreadIsMain()
@@ -117,6 +119,12 @@ namespace AS {
     /// Constructs a plain mutex (the default).
     Mutex () : Mutex (false) {}
 
+    void SetDebugNameWithObject(id object) {
+#if ASEnableVerboseLogging && ASDISPLAYNODE_ASSERTIONS_ENABLED
+      _debug_name = std::string(ASObjectDescriptionMakeTiny(object).UTF8String);
+#endif
+    }
+
     ~Mutex () {
       // Manually destroy since unions can't do it.
       switch (_type) {
@@ -243,6 +251,11 @@ namespace AS {
 
     void WillUnlock() {
 #if ASDISPLAYNODE_ASSERTIONS_ENABLED
+#if ASEnableVerboseLogging
+      if (!_debug_name.empty()) {
+        as_log_verbose(ASLockingLog(), "unlock %s, count is %d", _debug_name.c_str(), (int)(_count - 1));
+      }
+#endif
       if (--_count == 0) {
         _owner = std::thread::id();
       }
@@ -251,6 +264,11 @@ namespace AS {
 
     void DidLock() {
 #if ASDISPLAYNODE_ASSERTIONS_ENABLED
+#if ASEnableVerboseLogging
+      if (!_debug_name.empty()) {
+        as_log_verbose(ASLockingLog(), "lock %s, count is %d", _debug_name.c_str(), (int)(_count + 1));
+      }
+#endif
       if (++_count == 1) {
         // New owner.
         _owner = std::this_thread::get_id();
@@ -265,6 +283,10 @@ namespace AS {
       std::mutex _plain;
       std::recursive_mutex _recursive;
     };
+#if ASEnableVerboseLogging
+    std::string _debug_name;
+#endif
+
 #if ASDISPLAYNODE_ASSERTIONS_ENABLED
     std::thread::id _owner = std::thread::id();
     int _count = 0;