[ReactNative] Refactor RCTDataManager to support pluggable data source modules (RCTURLRequestHandlers)

Summary:
@public

This is a refactor of @philikon's original diff that decouples the dependencies between the Network and Image modules, and replaces RCTDataQueryExecutor with a more useful abstraction.

I've introduced the RCTURLRequestHandler protocol, which is a new type of bridge module used for loading data using an NSURLRequest. RCTURLRequestHandlers can be registered using RCT_EXPORT_MODULE() and are then available at runtime for use by the RCTDataManager, which will automatically select the appropriate handler for a given request based on the handler's self-reported capabilities.

The currently implemented handlers are:

- RCTHTTPRequestHandler - the standard open source HTTP request handler that uses NSURLSession
- RKHTTPRequestHandler - the internal FB HTTP request handler that uses FBNetworking
- RCTImageRequestHandler - a handler for loading local images from the iOS asset-library

Depends on D2108193

Test Plan:
- Internal apps still work
- OSS port still compiles, Movies app and a sample Parse app still work
- uploading image to Parse using the above code snippet works
- tested `FormData` with string and image parameters using http://www.posttestserver.com/

Author: nicklockwood

Libraries/Image/RCTImage.xcodeproj/project.pbxproj

@@ -10,6 +10,7 @@
 		1304D5AB1AA8C4A30002E2BE /* RCTStaticImage.m in Sources */ = {isa = PBXBuildFile; fileRef = 1304D5A81AA8C4A30002E2BE /* RCTStaticImage.m */; };
 		1304D5AC1AA8C4A30002E2BE /* RCTStaticImageManager.m in Sources */ = {isa = PBXBuildFile; fileRef = 1304D5AA1AA8C4A30002E2BE /* RCTStaticImageManager.m */; };
 		1304D5B21AA8C50D0002E2BE /* RCTGIFImage.m in Sources */ = {isa = PBXBuildFile; fileRef = 1304D5B11AA8C50D0002E2BE /* RCTGIFImage.m */; };
+		1345A8391B26592900583190 /* RCTImageRequestHandler.m in Sources */ = {isa = PBXBuildFile; fileRef = 1345A8381B26592900583190 /* RCTImageRequestHandler.m */; };
 		143879351AAD238D00F088A5 /* RCTCameraRollManager.m in Sources */ = {isa = PBXBuildFile; fileRef = 143879341AAD238D00F088A5 /* RCTCameraRollManager.m */; };
 		143879381AAD32A300F088A5 /* RCTImageLoader.m in Sources */ = {isa = PBXBuildFile; fileRef = 143879371AAD32A300F088A5 /* RCTImageLoader.m */; };
 		58B5118F1A9E6BD600147676 /* RCTImageDownloader.m in Sources */ = {isa = PBXBuildFile; fileRef = 58B5118A1A9E6BD600147676 /* RCTImageDownloader.m */; };
@@ -36,6 +37,8 @@
 		1304D5AA1AA8C4A30002E2BE /* RCTStaticImageManager.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = RCTStaticImageManager.m; sourceTree = "<group>"; };
 		1304D5B01AA8C50D0002E2BE /* RCTGIFImage.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = RCTGIFImage.h; sourceTree = "<group>"; };
 		1304D5B11AA8C50D0002E2BE /* RCTGIFImage.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = RCTGIFImage.m; sourceTree = "<group>"; };
+		1345A8371B26592900583190 /* RCTImageRequestHandler.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = RCTImageRequestHandler.h; sourceTree = "<group>"; };
+		1345A8381B26592900583190 /* RCTImageRequestHandler.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = RCTImageRequestHandler.m; sourceTree = "<group>"; };
 		143879331AAD238D00F088A5 /* RCTCameraRollManager.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = RCTCameraRollManager.h; sourceTree = "<group>"; };
 		143879341AAD238D00F088A5 /* RCTCameraRollManager.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = RCTCameraRollManager.m; sourceTree = "<group>"; };
 		143879361AAD32A300F088A5 /* RCTImageLoader.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = RCTImageLoader.h; sourceTree = "<group>"; };
@@ -71,6 +74,8 @@
 				1304D5B11AA8C50D0002E2BE /* RCTGIFImage.m */,
 				58B511891A9E6BD600147676 /* RCTImageDownloader.h */,
 				58B5118A1A9E6BD600147676 /* RCTImageDownloader.m */,
+				1345A8371B26592900583190 /* RCTImageRequestHandler.h */,
+				1345A8381B26592900583190 /* RCTImageRequestHandler.m */,
 				58B5118B1A9E6BD600147676 /* RCTNetworkImageView.h */,
 				58B5118C1A9E6BD600147676 /* RCTNetworkImageView.m */,
 				58B5118D1A9E6BD600147676 /* RCTNetworkImageViewManager.h */,
@@ -152,6 +157,7 @@
 				58B5118F1A9E6BD600147676 /* RCTImageDownloader.m in Sources */,
 				58B511911A9E6BD600147676 /* RCTNetworkImageViewManager.m in Sources */,
 				1304D5AC1AA8C4A30002E2BE /* RCTStaticImageManager.m in Sources */,
+				1345A8391B26592900583190 /* RCTImageRequestHandler.m in Sources */,
 				58B511901A9E6BD600147676 /* RCTNetworkImageView.m in Sources */,
 				1304D5B21AA8C50D0002E2BE /* RCTGIFImage.m in Sources */,
 				143879351AAD238D00F088A5 /* RCTCameraRollManager.m in Sources */,

Libraries/Image/RCTImageLoader.h

@@ -23,6 +23,4 @@
 + (void)loadImageWithTag:(NSString *)tag
                 callback:(void (^)(NSError *error, id /* UIImage or CAAnimation */ image))callback;
 
-+ (BOOL)isSystemImageURI:(NSString *)uri;
-
 @end

Libraries/Image/RCTImageLoader.m

@@ -16,11 +16,23 @@
 #import <UIKit/UIKit.h>
 
 #import "RCTConvert.h"
+#import "RCTDefines.h"
 #import "RCTGIFImage.h"
 #import "RCTImageDownloader.h"
 #import "RCTLog.h"
 #import "RCTUtils.h"
 
+static void RCTDispatchCallbackOnMainQueue(void (^ __nonnull callback)(NSError *, id), NSError *error, UIImage *image)
+{
+  if ([NSThread isMainThread]) {
+    callback(error, image);
+  } else {
+    dispatch_async(dispatch_get_main_queue(), ^{
+      callback(error, image);
+    });
+  }
+}
+
 static dispatch_queue_t RCTImageLoaderQueue(void)
 {
   static dispatch_queue_t queue = NULL;
@@ -137,11 +149,4 @@ + (void)loadImageWithTag:(NSString *)imageTag callback:(void (^)(NSError *error,
   }
 }
 
-+ (BOOL)isSystemImageURI:(NSString *)uri
-{
-  return uri != nil && (
-   [uri hasPrefix:@"assets-library"] ||
-   [uri hasPrefix:@"ph://"]);
-}
-
 @end

Libraries/Network/RCTDataQuery.h Libraries/Image/RCTImageRequestHandler.hLibraries/Network/RCTDataQuery.h renamed to Libraries/Image/RCTImageRequestHandler.h

@@ -7,15 +7,8 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
-#import "RCTBridgeModule.h"
+#import "RCTURLRequestHandler.h"
 
-@protocol RCTDataQueryExecutor <NSObject>
-
-- (void)addQuery:(NSDictionary *)query responseSender:(RCTResponseSenderBlock)responseSender;
-
-@optional
-
-@property (nonatomic, weak) RCTBridge *bridge;
-@property (nonatomic, assign) BOOL sendIncrementalUpdates;
+@interface RCTImageRequestHandler : NSObject <RCTURLRequestHandler>
 
 @end

Libraries/Image/RCTImageRequestHandler.m

@@ -0,0 +1,62 @@
+//
+//  RCTImageRequestHandler.m
+//  RCTImage
+//
+//  Created by Nick Lockwood on 09/06/2015.
+//  Copyright (c) 2015 Facebook. All rights reserved.
+//
+
+#import "RCTImageRequestHandler.h"
+
+#import <UIKit/UIKit.h>
+
+#import "RCTImageLoader.h"
+#import "RCTUtils.h"
+
+@implementation RCTImageRequestHandler
+{
+  NSInteger _currentToken;
+}
+
+RCT_EXPORT_MODULE()
+
+- (BOOL)canHandleRequest:(NSURLRequest *)request
+{
+  return [@[@"assets-library", @"ph"] containsObject:[request.URL.scheme lowercaseString]];
+}
+
+- (id)sendRequest:(NSURLRequest *)request
+     withDelegate:(id<RCTURLRequestDelegate>)delegate
+{
+  NSNumber *requestToken = @(++_currentToken);
+  NSString *URLString = [request.URL absoluteString];
+  [RCTImageLoader loadImageWithTag:URLString callback:^(NSError *error, UIImage *image) {
+    if (error) {
+      [delegate URLRequest:requestToken didCompleteWithError:error];
+      return;
+    }
+
+    NSString *mimeType = nil;
+    NSData *imageData = nil;
+    if (RCTImageHasAlpha(image.CGImage)) {
+      mimeType = @"image/png";
+      imageData = UIImagePNGRepresentation(image);
+    } else {
+      mimeType = @"image/jpeg";
+      imageData = UIImageJPEGRepresentation(image, 1.0);
+    }
+
+    NSURLResponse *response = [[NSURLResponse alloc] initWithURL:request.URL
+                                                        MIMEType:mimeType
+                                           expectedContentLength:imageData.length
+                                                textEncodingName:nil];
+
+    [delegate URLRequest:requestToken didReceiveResponse:response];
+    [delegate URLRequest:requestToken didReceiveData:imageData];
+    [delegate URLRequest:requestToken didCompleteWithError:nil];
+  }];
+
+  return requestToken;
+}
+
+@end