Add a function to disable all logging at runtime (#528)

* Implement a runtime disable for all logging

* Update the changelog

* Inline the function

* Flip the scrip

CHANGELOG.md

@@ -11,6 +11,7 @@
 - Remove re-entrant access to self.view when applying initial pending state. [Adlai Holler](https://github.com/Adlai-Holler) [#510](https://github.com/TextureGroup/Texture/pull/510)
 - Small improvements in ASCollectionLayout [Huy Nguyen](https://github.com/nguyenhuy) [#509](https://github.com/TextureGroup/Texture/pull/509) [#513](https://github.com/TextureGroup/Texture/pull/513)
 - Fix retain cycle between ASImageNode and PINAnimatedImage [Phil Larson](https://github.com/plarson) [#520](https://github.com/TextureGroup/Texture/pull/520)
+- Change the API for disabling logging from a compiler flag to a runtime C function ASDisableLogging().  [Adlai Holler](https://github.com/Adlai-Holler) [#528](https://github.com/TextureGroup/Texture/pull/528)
 - Table and collection views to consider content inset when calculating (default) element size range [Huy Nguyen](https://github.com/nguyenhuy) [#525](https://github.com/TextureGroup/Texture/pull/525)
 
 ##2.4

Source/Base/ASLog.h

@@ -21,16 +21,27 @@
 #import <os/log.h>
 #import <os/activity.h>
 
-#ifndef ASEnableLogs
-  #define ASEnableLogs 1
-#endif
-
 #ifndef ASEnableVerboseLogging
   #define ASEnableVerboseLogging 0
 #endif
 
 ASDISPLAYNODE_EXTERN_C_BEGIN
 
+/**
+ * Disable all logging.
+ *
+ * You should only use this function if the default log level is
+ * annoying during development. By default, logging is run at
+ * the appropriate system log level (see the os_log_* functions),
+ * so you do not need to worry generally about the performance
+ * implications of log messages.
+ *
+ * For example, virtually all log messages generated by Texture
+ * are at the `debug` log level, which the system
+ * disables in production.
+ */
+void ASDisableLogging();
+
 /// Log for general node events e.g. interfaceState, didLoad.
 #define ASNodeLogEnabled 1
 os_log_t ASNodeLog();

Source/Base/ASLog.m

@@ -11,27 +11,41 @@
 //
 
 #import <AsyncDisplayKit/ASLog.h>
+#import <stdatomic.h>
+
+static atomic_bool __ASLogEnabled = ATOMIC_VAR_INIT(YES);
+
+void ASDisableLogging() {
+  static dispatch_once_t onceToken;
+  dispatch_once(&onceToken, ^{
+    atomic_store(&__ASLogEnabled, NO);
+  });
+}
+
+ASDISPLAYNODE_INLINE BOOL ASLoggingIsEnabled() {
+  return atomic_load(&__ASLogEnabled);
+}
 
 os_log_t ASNodeLog() {
-  return ASCreateOnce((ASEnableLogs && ASNodeLogEnabled) ? as_log_create("org.TextureGroup.Texture", "Node") : OS_LOG_DISABLED);
+  return (ASNodeLogEnabled && ASLoggingIsEnabled()) ? ASCreateOnce(as_log_create("org.TextureGroup.Texture", "Node")) : OS_LOG_DISABLED;
 }
 
 os_log_t ASLayoutLog() {
-  return ASCreateOnce((ASEnableLogs && ASLayoutLogEnabled) ? as_log_create("org.TextureGroup.Texture", "Layout") : OS_LOG_DISABLED);
+  return (ASLayoutLogEnabled && ASLoggingIsEnabled()) ? ASCreateOnce(as_log_create("org.TextureGroup.Texture", "Layout")) : OS_LOG_DISABLED;
 }
 
 os_log_t ASCollectionLog() {
-  return ASCreateOnce((ASEnableLogs && ASCollectionLogEnabled) ? as_log_create("org.TextureGroup.Texture", "Collection") : OS_LOG_DISABLED);
+  return (ASCollectionLogEnabled && ASLoggingIsEnabled()) ?ASCreateOnce(as_log_create("org.TextureGroup.Texture", "Collection")) : OS_LOG_DISABLED;
 }
 
 os_log_t ASDisplayLog() {
-  return ASCreateOnce((ASEnableLogs && ASDisplayLogEnabled) ? as_log_create("org.TextureGroup.Texture", "Display") : OS_LOG_DISABLED);
+  return (ASDisplayLogEnabled && ASLoggingIsEnabled()) ?ASCreateOnce(as_log_create("org.TextureGroup.Texture", "Display")) : OS_LOG_DISABLED;
 }
 
 os_log_t ASImageLoadingLog() {
-  return ASCreateOnce((ASEnableLogs && ASImageLoadingLogEnabled) ? as_log_create("org.TextureGroup.Texture", "ImageLoading") : OS_LOG_DISABLED);
+  return (ASImageLoadingLogEnabled && ASLoggingIsEnabled()) ? ASCreateOnce(as_log_create("org.TextureGroup.Texture", "ImageLoading")) : OS_LOG_DISABLED;
 }
 
 os_log_t ASMainThreadDeallocationLog() {
-  return ASCreateOnce((ASEnableLogs && ASMainThreadDeallocationLogEnabled) ? as_log_create("org.TextureGroup.Texture", "MainDealloc") : OS_LOG_DISABLED);
+  return (ASMainThreadDeallocationLogEnabled && ASLoggingIsEnabled()) ? ASCreateOnce(as_log_create("org.TextureGroup.Texture", "MainDealloc")) : OS_LOG_DISABLED;
 }