Create a centralized configuration API (#747)

* Update the dangerfile

* Make a trivial change to test new dangerfile

* Try out the new value with another trivial change

* Add a configuration API to make a unified place for pulling config from clients safely

* Specify properties for delegate

* Finish removing text experiment global enable

* Generate the config file

* Clean up configuration to fix tests

* Work on making it serializable

* Finish it up

* Fix example code

* Update sample project

* Clean up a few things

* Align with new project order

* Make it faster and update license header

* Add an option to specify your config at compile time

* Update another license header

* Add a version field, and bring interface state coalescing into configuration

* Update CA queue code

* Update CATransactionQueue tests

* Turn transaction queue on by default (for now, see comment)

* Update the tests

* Update the tests AGAIN

* Remove unused ordered set

CHANGELOG.md

@@ -25,6 +25,7 @@
 - [ASCollectionNode] Added support for interactive item movement. [Adlai Holler](https://github.com/Adlai-Holler)
 - Added an experimental "no-copy" rendering API. See ASGraphicsContext.h for info. [Adlai Holler](https://github.com/Adlai-Holler)
 - Dropped support for iOS 8. [Adlai Holler](https://github.com/Adlai-Holler)
+- Added a configuration API – a unified place to turn on/off experimental Texture features. See `ASConfiguration.h` for info. [Adlai Holler](https://github.com/Adlai-Holler)
 - **Breaking** Changes to ASNetworkImageNode: [Adlai Holler](https://github.com/Adlai-Holler)
   - Modified `ASImageDownloaderCompletion` to add an optional `id userInfo` field. Your custom downloader can pass `nil`.
   - Modified the last argument to `-[ASNetworkImageNodeDelegate imageNode:didLoadImage:info:]` method from a struct to an object of new class `ASNetworkImageLoadInfo` which includes other metadata about the load operation.

Schemas/configuration.json

@@ -0,0 +1,23 @@
+{
+    "id": "configuration.json",
+    "title": "configuration",
+    "description" : "Schema definition of a Texture Configuration",
+    "$schema": "http://json-schema.org/schema#",
+    "type": "object",
+    "properties": {
+      "version" : {
+        "type" : "number"
+      },
+    	"experimental_features": {
+    		"type": "array",
+    		"items": {
+        		"type": "string",
+        		"enum": [
+                    "exp_graphics_contexts",
+                    "exp_text_node",
+                    "exp_interface_state_coalesce"
+                ]
+    		}
+		}
+    }
+}

Source/ASConfiguration.h

@@ -0,0 +1,62 @@
+//
+//  ASConfiguration.h
+//  Texture
+//
+//  Copyright (c) 2018-present, Pinterest, Inc.  All rights reserved.
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+
+#import <Foundation/Foundation.h>
+#import <AsyncDisplayKit/ASBaseDefines.h>
+#import <AsyncDisplayKit/ASExperimentalFeatures.h>
+
+@protocol ASConfigurationDelegate;
+
+NS_ASSUME_NONNULL_BEGIN
+
+static NSInteger const ASConfigurationSchemaCurrentVersion = 1;
+
+AS_SUBCLASSING_RESTRICTED
+@interface ASConfiguration : NSObject <NSCopying>
+
+/**
+ * Initialize this configuration with the provided dictionary,
+ * or nil to create an empty configuration.
+ *
+ * The schema is located in `schemas/configuration.json`.
+ */
+- (instancetype)initWithDictionary:(nullable NSDictionary *)dictionary;
+
+/**
+ * The delegate for configuration-related events.
+ * Delegate methods are called from a serial queue.
+ */
+@property (nonatomic, strong, nullable) id<ASConfigurationDelegate> delegate;
+
+/**
+ * The experimental features to enable in Texture.
+ * See ASExperimentalFeatures for functions to convert to/from a string array.
+ */
+@property (nonatomic) ASExperimentalFeatures experimentalFeatures;
+
+@end
+
+/**
+ * Implement this method in a category to make your
+ * configuration available to Texture. It will be read
+ * only once and copied.
+ *
+ * NOTE: To specify your configuration at compile-time, you can
+ * define AS_FIXED_CONFIG_JSON as a C-string of JSON. This method
+ * will then be implemented to parse that string and generate
+ * a configuration.
+ */
+@interface ASConfiguration (UserProvided)
++ (ASConfiguration *)textureConfiguration NS_RETURNS_RETAINED;
+@end
+
+NS_ASSUME_NONNULL_END

Source/ASConfiguration.m

@@ -0,0 +1,67 @@
+//
+//  ASConfiguration.m
+//  Texture
+//
+//  Copyright (c) 2018-present, Pinterest, Inc.  All rights reserved.
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+
+#import <AsyncDisplayKit/ASConfiguration.h>
+#import <AsyncDisplayKit/ASConfigurationInternal.h>
+
+/// Not too performance-sensitive here.
+
+/// Get this from C++, without the extra exception handling.
+#define autotype __auto_type
+
+@implementation ASConfiguration
+
+- (instancetype)initWithDictionary:(NSDictionary *)dictionary
+{
+  if (self = [super init]) {
+    autotype featureStrings = ASDynamicCast(dictionary[@"experimental_features"], NSArray);
+    autotype version = ASDynamicCast(dictionary[@"version"], NSNumber).integerValue;
+    if (version != ASConfigurationSchemaCurrentVersion) {
+      NSLog(@"Texture warning: configuration schema is old version (%zd vs %zd)", version, ASConfigurationSchemaCurrentVersion);
+    }
+    self.experimentalFeatures = ASExperimentalFeaturesFromArray(featureStrings);
+  }
+  return self;
+}
+
+- (id)copyWithZone:(NSZone *)zone
+{
+  ASConfiguration *config = [[ASConfiguration alloc] initWithDictionary:nil];
+  config.experimentalFeatures = self.experimentalFeatures;
+  config.delegate = self.delegate;
+  return config;
+}
+
+@end
+
+//#define AS_FIXED_CONFIG_JSON "{ \"version\" : 1, \"experimental_features\": [ \"exp_text_node\" ] }"
+
+#ifdef AS_FIXED_CONFIG_JSON
+
+@implementation ASConfiguration (UserProvided)
+
++ (ASConfiguration *)textureConfiguration NS_RETURNS_RETAINED
+{
+  NSData *data = [@AS_FIXED_CONFIG_JSON dataUsingEncoding:NSUTF8StringEncoding];
+  NSError *error;
+  NSDictionary *d = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
+  if (!d) {
+    NSAssert(NO, @"Error parsing fixed config string '%s': %@", AS_FIXED_CONFIG_JSON, error);
+    return nil;
+  } else {
+    return [[ASConfiguration alloc] initWithDictionary:d];
+  }
+}
+
+@end
+
+#endif // AS_FIXED_CONFIG_JSON

Source/ASConfigurationDelegate.h

@@ -0,0 +1,31 @@
+//
+//  ASConfigurationDelegate.h
+//  Texture
+//
+//  Copyright (c) 2018-present, Pinterest, Inc.  All rights reserved.
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+
+#import <Foundation/Foundation.h>
+#import <AsyncDisplayKit/ASConfiguration.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+/**
+ * Used to communicate configuration-related events to the client.
+ */
+@protocol ASConfigurationDelegate <NSObject>
+
+/**
+ * Texture performed its first behavior related to the feature(s).
+ * This can be useful for tracking the impact of the behavior (A/B testing).
+ */
+- (void)textureDidActivateExperimentalFeatures:(ASExperimentalFeatures)features;
+
+@end
+
+NS_ASSUME_NONNULL_END

Source/ASDisplayNode.mm

@@ -2915,7 +2915,7 @@ - (void)didExitHierarchy
       }
     };
 
-    if ([[ASCATransactionQueue sharedQueue] disabled]) {
+    if (!ASCATransactionQueue.sharedQueue.enabled) {
       dispatch_async(dispatch_get_main_queue(), exitVisibleInterfaceState);
     } else {
       exitVisibleInterfaceState();
@@ -2980,7 +2980,7 @@ - (ASInterfaceState)interfaceState
 
 - (void)setInterfaceState:(ASInterfaceState)newState
 {
-  if ([[ASCATransactionQueue sharedQueue] disabled]) {
+  if (!ASCATransactionQueue.sharedQueue.enabled) {
     [self applyPendingInterfaceState:newState];
   } else {
     ASDN::MutexLocker l(__instanceLock__);
@@ -3012,7 +3012,7 @@ - (void)applyPendingInterfaceState:(ASInterfaceState)newPendingState
     ASDN::MutexLocker l(__instanceLock__);
     // newPendingState will not be used when ASCATransactionQueue is enabled
     // and use _pendingInterfaceState instead for interfaceState update.
-    if ([[ASCATransactionQueue sharedQueue] disabled]) {
+    if (!ASCATransactionQueue.sharedQueue.enabled) {
       _pendingInterfaceState = newPendingState;
     }
     oldState = _interfaceState;

Source/ASExperimentalFeatures.h

@@ -0,0 +1,36 @@
+//
+//  ASExperimentalFeatures.h
+//  Texture
+//
+//  Copyright (c) 2018-present, Pinterest, Inc.  All rights reserved.
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+
+#import <Foundation/Foundation.h>
+#import <AsyncDisplayKit/ASBaseDefines.h>
+
+NS_ASSUME_NONNULL_BEGIN
+ASDISPLAYNODE_EXTERN_C_BEGIN
+
+/**
+ * A bit mask of features.
+ */
+typedef NS_OPTIONS(NSUInteger, ASExperimentalFeatures) {
+  ASExperimentalGraphicsContexts = 1 << 0,                  // exp_graphics_contexts
+  ASExperimentalTextNode = 1 << 1,                          // exp_text_node
+  ASExperimentalInterfaceStateCoalescing = 1 << 2,          // exp_interface_state_coalesce
+  ASExperimentalFeatureAll = 0xFFFFFFFF
+};
+
+/// Convert flags -> name array.
+NSArray<NSString *> *ASExperimentalFeaturesGetNames(ASExperimentalFeatures flags);
+
+/// Convert name array -> flags.
+ASExperimentalFeatures ASExperimentalFeaturesFromArray(NSArray<NSString *> *array);
+
+ASDISPLAYNODE_EXTERN_C_END
+NS_ASSUME_NONNULL_END

Source/ASExperimentalFeatures.m

@@ -0,0 +1,45 @@
+//
+//  ASExperimentalFeatures.m
+//  Texture
+//
+//  Copyright (c) 2018-present, Pinterest, Inc.  All rights reserved.
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+
+#import <AsyncDisplayKit/ASExperimentalFeatures.h>
+
+NSArray<NSString *> *ASExperimentalFeaturesGetNames(ASExperimentalFeatures flags)
+{
+  NSArray *allNames = ASCreateOnce((@[@"exp_graphics_contexts",
+                                      @"exp_text_node",
+                                      @"exp_interface_state_coalesce"]));
+
+  if (flags == ASExperimentalFeatureAll) {
+    return allNames;
+  }
+
+  // Go through all names, testing each bit.
+  NSUInteger i = 0;
+  return ASArrayByFlatMapping(allNames, NSString *name, ({
+    (flags & (1 << i++)) ? name : nil;
+  }));
+}
+
+// O(N^2) but with counts this small, it's probably faster
+// than hashing the strings.
+ASExperimentalFeatures ASExperimentalFeaturesFromArray(NSArray<NSString *> *array)
+{
+  NSArray *allNames = ASExperimentalFeaturesGetNames(ASExperimentalFeatureAll);
+  ASExperimentalFeatures result = 0;
+  for (NSString *str in array) {
+    NSUInteger i = [allNames indexOfObject:str];
+    if (i != NSNotFound) {
+      result |= (1 << i);
+    }
+  }
+  return result;
+}

Source/ASNetworkImageLoadInfo.h

@@ -1,9 +1,13 @@
 //
 //  ASNetworkImageLoadInfo.h
-//  AsyncDisplayKit
+//  Texture
 //
-//  Created by Adlai on 1/30/18.
-//  Copyright © 2018 Facebook. All rights reserved.
+//  Copyright (c) 2018-present, Pinterest, Inc.  All rights reserved.
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
 //
 
 #import <Foundation/Foundation.h>

Source/ASNetworkImageLoadInfo.m

@@ -1,9 +1,13 @@
 //
 //  ASNetworkImageLoadInfo.m
-//  AsyncDisplayKit
+//  Texture
 //
-//  Created by Adlai on 1/30/18.
-//  Copyright © 2018 Facebook. All rights reserved.
+//  Copyright (c) 2018-present, Pinterest, Inc.  All rights reserved.
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
 //
 
 #import <AsyncDisplayKit/ASNetworkImageLoadInfo.h>

Source/ASRunLoopQueue.h

@@ -59,7 +59,9 @@ AS_SUBCLASSING_RESTRICTED
 @interface ASCATransactionQueue : ASAbstractRunLoopQueue
 
 @property (atomic, readonly) BOOL isEmpty;
-@property (atomic, readonly) BOOL disabled;
+
+@property (atomic, readonly, getter=isEnabled) BOOL enabled;
+
 /**
  * The queue to run on main run loop before CATransaction commit.
  *
@@ -72,11 +74,6 @@ AS_SUBCLASSING_RESTRICTED
 
 - (void)enqueue:(id<ASCATransactionQueueObserving>)object;
 
-/**
- * @abstract Apply a node's interfaceState immediately rather than adding to the queue.
- */
-- (void)disable;
-
 @end