Refactor hot loading implementation on iOS

Reviewed By: milend

Differential Revision: D2795580

fb-gh-sync-id: ad33ba152e40b622b10bfa0122afd6edc28a11bf

React/Base/RCTBatchedBridge.m

@@ -440,6 +440,16 @@ RCT_EXTERN NSArray<Class> *RCTGetModuleClasses(void);
        object:_parentBridge userInfo:@{@"bridge": self}];
     });
   }];
+
+#if RCT_DEV
+
+  if (RCTGetURLQueryParam(self.bundleURL, @"hot")) {
+    NSString *path = [self.bundleURL.path substringFromIndex:1]; // strip initial slash
+    [self enqueueJSCall:@"HMRClient.enable" args:@[@"ios", path]];
+  }
+
+#endif
+
 }
 
 - (void)didFinishLoading

React/Base/RCTBridge+Private.h

@@ -41,6 +41,11 @@
  */
 @property (nonatomic, copy, readonly) RCTBridgeModuleProviderBlock moduleProvider;
 
+/**
+ * Used by RCTDevMenu to override the `hot` param of the current bundleURL.
+ */
+@property (nonatomic, strong, readwrite) NSURL *bundleURL;
+
 @end
 
 @interface RCTBridge (RCTBatchedBridge)

React/Base/RCTBridge.h

@@ -123,11 +123,11 @@ RCT_EXTERN BOOL RCTBridgeModuleClassIsRegistered(Class);
 /**
  * URL of the script that was loaded into the bridge.
  */
-@property (nonatomic, strong) NSURL *bundleURL;
+@property (nonatomic, strong, readonly) NSURL *bundleURL;
 
 /**
- * The class of the executor currently being used *or* to be used after the next
- * reload.
+ * The class of the executor currently being used. Changes to this value will
+ * take effect after the bridge is reloaded.
  */
 @property (nonatomic, strong) Class executorClass;
 

React/Base/RCTBridge.m

@@ -17,7 +17,6 @@
 #import "RCTLog.h"
 #import "RCTPerformanceLogger.h"
 #import "RCTUtils.h"
-#import "RCTBundleURLProcessor.h"
 
 NSString *const RCTReloadNotification = @"RCTReloadNotification";
 NSString *const RCTJavaScriptWillStartLoadingNotification = @"RCTJavaScriptWillStartLoadingNotification";
@@ -88,6 +87,9 @@ BOOL RCTBridgeModuleClassIsRegistered(Class cls)
 }
 
 @implementation RCTBridge
+{
+  NSURL *_delegateBundleURL;
+}
 
 dispatch_queue_t RCTJSThread;
 
@@ -257,8 +259,12 @@ RCT_NOT_IMPLEMENTED(- (instancetype)init)
 {
   RCTAssertMainThread();
 
-  _bundleURL = [self.delegate sourceURLForBridge:self] ?: _bundleURL;
-  _bundleURL = [[RCTBundleURLProcessor sharedProcessor] process: _bundleURL];
+  // Only update bundleURL from delegate if delegate bundleURL has changed
+  NSURL *previousDelegateURL = _delegateBundleURL;
+  _delegateBundleURL = [self.delegate sourceURLForBridge:self];
+  if (_delegateBundleURL && ![_delegateBundleURL isEqual:previousDelegateURL]) {
+    _bundleURL = _delegateBundleURL;
+  }
 
   // Sanitize the bundle URL
   _bundleURL = [RCTConvert NSURL:_bundleURL.absoluteString];

React/Base/RCTBridgeDelegate.h

@@ -48,9 +48,9 @@ typedef void (^RCTSourceLoadBlock)(NSError *error, NSData *source);
                   withBlock:(RCTSourceLoadBlock)loadCallback;
 
 /**
- * Indicates wheather Hot Loading is supported or not.
- * Note this method will get removed soon, once we support Hot Loading on OSS.
+ * Indicates whether Hot Loading is supported or not.
+ * Note: this method will be removed soon, once Hot Loading is supported on OSS.
  */
-- (BOOL)isHotLoadingEnabled;
+- (BOOL)bridgeSupportsHotLoading:(RCTBridge *)bridge;
 
 @end

React/Base/RCTBundleURLProcessor.h

@@ -1,18 +0,0 @@
-/**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
- *
- * This source code is licensed under the BSD-style license found in the
- * LICENSE file in the root directory of this source tree. An additional grant
- * of patent rights can be found in the PATENTS file in the same directory.
- */
-
-@interface RCTBundleURLProcessor : NSObject
-
-+ (id)sharedProcessor;
-
-- (NSString *)getQueryStringValue:(NSString *)attribute;
-- (void)setQueryStringValue:(NSString *)value forAttribute:(NSString *)attribute;
-- (NSURL *)process:(NSURL *)url;
-
-@end

React/Base/RCTBundleURLProcessor.m

@@ -1,73 +0,0 @@
-/**
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
- *
- * This source code is licensed under the BSD-style license found in the
- * LICENSE file in the root directory of this source tree. An additional grant
- * of patent rights can be found in the PATENTS file in the same directory.
- */
-
-#import <Foundation/Foundation.h>
-
-#import "RCTBundleURLProcessor.h"
-
-@implementation RCTBundleURLProcessor
-
-NSDictionary *_qsAttributes;
-
-+ (id)sharedProcessor
-{
-  static RCTBundleURLProcessor *sharedProcessor = nil;
-  static dispatch_once_t onceToken;
-  dispatch_once(&onceToken, ^{
-    sharedProcessor = [self new];
-  });
-  return sharedProcessor;
-}
-
-- (instancetype)init
-{
-  // dictionary with additional query string attributes that will get appended
-  // to the bundle URL
-  _qsAttributes = [NSMutableDictionary new];
-  return self;
-}
-
-- (NSString *)getQueryStringValue:(NSString *)attribute
-{
-  return [_qsAttributes valueForKey:attribute];
-}
-
-- (void)setQueryStringValue:(NSString *)value forAttribute:(NSString *)attribute
-{
-  [_qsAttributes setValue:value forKey:attribute];
-}
-
-- (NSURL *)process:(NSURL *)url
-{
-  if (url.isFileURL || [_qsAttributes count] == 0) {
-    return url;
-  }
-
-  // append either `?` or `&` depending on whether there are query string
-  // attibutes or not.
-  NSString *urlString = url.absoluteString;
-  if ([urlString rangeOfString:@"?"].location == NSNotFound) {
-    urlString = [urlString stringByAppendingString:@"?"];
-  } else {
-    urlString = [urlString stringByAppendingString:@"&"];
-  }
-
-  // array with new query string attributes
-  NSMutableArray *parts = [NSMutableArray new];
-  for (id attribute in _qsAttributes) {
-    if ([urlString rangeOfString:[NSString stringWithFormat:@"%@=", attribute]].location != NSNotFound) {
-      [NSException raise:@"Cannot override attribute" format:@"Attribute %@ is already present in url: %@", attribute, url.absoluteString];
-    }
-    [parts addObject:[NSString stringWithFormat:@"%@=%@", attribute, _qsAttributes[attribute]]];
-  }
-
-  return [NSURL URLWithString:[NSString stringWithFormat:@"%@%@", urlString, [parts componentsJoinedByString:@"&"]]];
-}
-
-@end

React/Base/RCTUtils.h

@@ -105,3 +105,7 @@ RCT_EXTERN NSString *RCTColorToHexString(CGColorRef color);
 
 // Get standard localized string (if it exists)
 RCT_EXTERN NSString *RCTUIKitLocalizedString(NSString *string);
+
+// URL manipulation
+RCT_EXTERN NSString *RCTGetURLQueryParam(NSURL *URL, NSString *param);
+RCT_EXTERN NSURL *RCTURLByReplacingQueryParam(NSURL *URL, NSString *param, NSString *value);

React/Base/RCTUtils.m

@@ -576,10 +576,53 @@ NSString *RCTColorToHexString(CGColorRef color)
   }
 }
 
-
 // (https://github.com/0xced/XCDFormInputAccessoryView/blob/master/XCDFormInputAccessoryView/XCDFormInputAccessoryView.m#L10-L14)
-RCT_EXTERN NSString *RCTUIKitLocalizedString(NSString *string)
+NSString *RCTUIKitLocalizedString(NSString *string)
 {
   NSBundle *UIKitBundle = [NSBundle bundleForClass:[UIApplication class]];
   return UIKitBundle ? [UIKitBundle localizedStringForKey:string value:string table:nil] : string;
 }
+
+NSString *RCTGetURLQueryParam(NSURL *URL, NSString *param)
+{
+  RCTAssertParam(param);
+  if (!URL) {
+    return nil;
+  }
+  NSURLComponents *components = [NSURLComponents componentsWithURL:URL
+                                           resolvingAgainstBaseURL:YES];
+  for (NSURLQueryItem *item in components.queryItems.reverseObjectEnumerator) {
+    if ([item.name isEqualToString:param]) {
+      return item.value;
+    }
+  }
+  return nil;
+}
+
+NSURL *RCTURLByReplacingQueryParam(NSURL *URL, NSString *param, NSString *value)
+{
+  RCTAssertParam(param);
+  if (!URL) {
+    return nil;
+  }
+  NSURLComponents *components = [NSURLComponents componentsWithURL:URL
+                                           resolvingAgainstBaseURL:YES];
+  __block NSInteger paramIndex = NSNotFound;
+  NSMutableArray *queryItems = [components.queryItems mutableCopy];
+  [queryItems enumerateObjectsWithOptions:NSEnumerationReverse usingBlock:
+   ^(NSURLQueryItem *item, NSUInteger i, BOOL *stop) {
+     if ([item.name isEqualToString:param]) {
+       paramIndex = i;
+       *stop = YES;
+     }
+   }];
+
+  NSURLQueryItem *newItem = [NSURLQueryItem queryItemWithName:param value:value];
+  if (paramIndex == NSNotFound) {
+    [queryItems addObject:newItem];
+  } else {
+    [queryItems replaceObjectAtIndex:paramIndex withObject:newItem];
+  }
+  components.queryItems = queryItems;
+  return components.URL;
+}