Initial commit

ReactKit/Base/RCTJavaScriptAppEngine.m

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+// Copyright 2004-present Facebook. All Rights Reserved.
+
+#import "RCTJavaScriptAppEngine.h"
+
+#import "RCTBridge.h"
+#import "RCTInvalidating.h"
+#import "RCTLog.h"
+#import "RCTRedBox.h"
+#import "RCTUtils.h"
+
+#define JS_SERVER_NOT_AVAILABLE @"Could not connect to development server. Ensure node server is running - run 'npm start' from ReactKit root"
+
+#define CACHE_DIR @"RCTJSBundleCache"
+
+#pragma mark - Application Engine
+
+/**
+ * TODO:
+ * - Add window resize rotation events matching the DOM API.
+ * - Device pixel ration hooks.
+ * - Source maps.
+ */
+@implementation RCTJavaScriptAppEngine
+{
+  BOOL _isPaused; // Pauses drawing/updating of the JSView
+  BOOL _pauseOnEnterBackground;
+  CADisplayLink *_displayLink;
+  NSTimer *_runTimer;
+  NSDictionary *_loadedResource;
+}
+
+- (instancetype)init
+{
+  RCT_NOT_DESIGNATED_INITIALIZER();
+}
+
+/**
+ * `CADisplayLink` code copied from Ejecta but we've placed the JavaScriptCore
+ * engine in its own dedicated thread.
+ *
+ * TODO: Try adding to the `RCTJavaScriptExecutor`'s thread runloop. Removes one
+ * additional GCD dispatch per frame and likely makes it so that other UIThread
+ * operations don't delay the dispatch (so we can begin working in JS much
+ * faster.) Event handling must still be sent via a GCD dispatch, of course.
+ *
+ * We must add the display link to two runloops in order to get setTimeouts to
+ * fire during scrolling. (`NSDefaultRunLoopMode` and `UITrackingRunLoopMode`)
+ * TODO: We can invent a `requestAnimationFrame` and
+ * `requestAvailableAnimationFrame` to control if callbacks can be fired during
+ * an animation.
+ * http://stackoverflow.com/questions/12622800/why-does-uiscrollview-pause-my-cadisplaylink
+ *
+ */
+- (instancetype)initWithBridge:(RCTBridge *)bridge
+{
+  RCTAssertMainThread();
+  if ((self = [super init])) {
+    _bridge = bridge;
+    _isPaused = NO;
+    self.pauseOnEnterBackground = YES;
+    _displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(run:)];
+    if (_displayLink) {
+      [_displayLink setFrameInterval:1];
+      [_displayLink addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
+    } else {
+      RCTLogWarn(@"Failed to create a display link (probably on buildbot) - using an NSTimer for AppEngine instead.");
+      _runTimer = [NSTimer scheduledTimerWithTimeInterval:(1.0 / 60.0) target:self selector:@selector(run:) userInfo:nil repeats:YES];
+    }
+  }
+  return self;
+}
+
+/**
+ * TODO: Wait until operations on `javaScriptQueue` are complete.
+ */
+- (void)dealloc
+{
+  RCTAssert(!self.valid, @"-invalidate must be called before -dealloc");
+}
+
+#pragma mark - RCTInvalidating
+
+- (BOOL)isValid
+{
+  return _displayLink != nil;
+}
+
+- (void)invalidate
+{
+  [_bridge invalidate];
+  _bridge = nil;
+
+  [_displayLink invalidate];
+  _displayLink = nil;
+
+  // Remove from notification center
+  self.pauseOnEnterBackground = NO;
+}
+
+#pragma mark - Run loop
+
+- (void)run:(CADisplayLink *)sender
+{
+  if (!_isPaused) {
+    RCTAssertMainThread();
+    [_bridge enqueueUpdateTimers];
+  }
+}
+
+- (void)pauseRunLoop
+{
+  if (!_isPaused) {
+    [_displayLink removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
+    _isPaused = YES;
+  }
+}
+
+- (void)resumeRunLoop
+{
+  if (_isPaused) {
+    [_displayLink addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
+    _isPaused = NO;
+  }
+}
+
+/**
+ * See warnings from lint: UIApplicationDidBecomeActive fires in a critical
+ * foreground path, and prevents the app from prioritizing the foreground
+ * processing. Consider using
+ * FBApplicationDidFinishEnteringForegroundAndIsNowIdleNotification.
+ */
+- (void)setPauseOnEnterBackground:(BOOL)pauses
+{
+  NSArray *pauseN = @[
+    UIApplicationWillResignActiveNotification,
+    UIApplicationDidEnterBackgroundNotification,
+    UIApplicationWillTerminateNotification
+  ];
+  NSArray *resumeN =
+    @[UIApplicationWillEnterForegroundNotification, UIApplicationDidBecomeActiveNotification];
+
+  if (pauses) {
+    [self observeKeyPaths:pauseN selector:@selector(pauseRunLoop)];
+    [self observeKeyPaths:resumeN selector:@selector(resumeRunLoop)];
+  }
+  else {
+    [self removeObserverForKeyPaths:pauseN];
+    [self removeObserverForKeyPaths:resumeN];
+  }
+  _pauseOnEnterBackground = pauses;
+}
+
+- (void)removeObserverForKeyPaths:(NSArray*)keyPaths
+{
+  NSNotificationCenter *nc = [NSNotificationCenter defaultCenter];
+  for (NSString *name in keyPaths) {
+    [nc removeObserver:self name:name object:nil];
+  }
+}
+
+- (void)observeKeyPaths:(NSArray*)keyPaths selector:(SEL)selector
+{
+  NSNotificationCenter *nc = [NSNotificationCenter defaultCenter];
+  for (NSString *name in keyPaths) {
+    [nc addObserver:self selector:selector name:name object:nil];
+  }
+}
+
+#pragma mark - Module and script loading
+
++ (void)resetCacheForBundleAtURL:(NSURL *)moduleURL
+{
+  NSString *rootPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];
+  NSString *fileDir = [rootPath stringByAppendingPathComponent:CACHE_DIR];
+  NSString *filePath = [fileDir stringByAppendingPathComponent:RCTMD5Hash(moduleURL.absoluteString)];
+  [[NSFileManager defaultManager] removeItemAtPath:filePath error:NULL];
+}
+
+/**
+ * TODO: All loading of script via network or disk should be done in a separate
+ * thread, not the JS thread, and not the main UI thread (launch blocker).
+ */
+- (void)loadBundleAtURL:(NSURL *)moduleURL useCache:(BOOL)useCache onComplete:(RCTJavaScriptCompleteBlock)onComplete
+{
+  NSString *cachedFilePath;
+  if (useCache) {
+    NSString *rootPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];
+    NSString *fileDir = [rootPath stringByAppendingPathComponent:CACHE_DIR];
+    cachedFilePath = [fileDir stringByAppendingPathComponent:RCTMD5Hash(moduleURL.absoluteString)];
+    if ([[NSFileManager defaultManager] fileExistsAtPath:cachedFilePath]) {
+      NSError *error;
+      NSString *rawText = [NSString stringWithContentsOfFile:cachedFilePath encoding:NSUTF8StringEncoding error:&error];
+      if (rawText.length == 0 || error != nil) {
+        if (onComplete) onComplete(error);
+      } else {
+        [self _enqueueLoadBundleResource:rawText url:moduleURL onComplete:onComplete];
+      }
+      return;
+    }
+  }
+
+  NSURLSessionDataTask *task = [[NSURLSession sharedSession] dataTaskWithURL:moduleURL completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
+    if (error != nil) {
+      if ([[error domain] isEqualToString:NSURLErrorDomain]) {
+        NSDictionary *userInfo = @{
+                                   NSLocalizedDescriptionKey: JS_SERVER_NOT_AVAILABLE,
+                                   NSLocalizedFailureReasonErrorKey: [error localizedDescription],
+                                   NSUnderlyingErrorKey: error,
+                                   };
+        error = [NSError errorWithDomain:@"JSServer"
+                                    code:error.code
+                                userInfo:userInfo];
+      }
+      if (onComplete) onComplete(error);
+      return;
+    }
+
+
+    NSStringEncoding encoding = NSUTF8StringEncoding;
+    if (response.textEncodingName != nil) {
+      CFStringEncoding cfEncoding = CFStringConvertIANACharSetNameToEncoding((CFStringRef)response.textEncodingName);
+      if (cfEncoding != kCFStringEncodingInvalidId) {
+        encoding = CFStringConvertEncodingToNSStringEncoding(cfEncoding);
+      }
+    }
+
+    NSString *rawText = [[NSString alloc] initWithData:data encoding:encoding];
+
+    if ([response isKindOfClass:[NSHTTPURLResponse class]] && [(NSHTTPURLResponse *)response statusCode] != 200) {
+      NSDictionary *userInfo;
+      NSDictionary *errorDetails = RCTJSONParse(rawText, nil);
+      if ([errorDetails isKindOfClass:[NSDictionary class]]) {
+        userInfo = @{
+                     NSLocalizedDescriptionKey: errorDetails[@"message"] ?: @"No message provided",
+                     @"stack": @[@{
+                                   @"methodName": errorDetails[@"description"] ?: @"",
+                                   @"file": errorDetails[@"filename"] ?: @"",
+                                   @"lineNumber": errorDetails[@"lineNumber"] ?: @0
+                                   }]
+                     };
+      } else {
+        userInfo = @{NSLocalizedDescriptionKey: rawText};
+      }
+      NSError *serverError = [NSError errorWithDomain:@"JSServer"
+                                                 code:[(NSHTTPURLResponse *)response statusCode]
+                                             userInfo:userInfo];
+      if (onComplete) onComplete(serverError);
+      return;
+    }
+
+    if (useCache) {
+      [[NSFileManager defaultManager] createDirectoryAtPath:cachedFilePath.stringByDeletingLastPathComponent withIntermediateDirectories:YES attributes:nil error:NULL];
+      [rawText writeToFile:cachedFilePath atomically:YES encoding:encoding error:NULL];
+    }
+
+    [self _enqueueLoadBundleResource:rawText url:moduleURL onComplete:onComplete];
+  }];
+  [task resume];
+}
+
+- (void)_enqueueLoadBundleResource:(NSString *)rawText url:(NSURL *)url onComplete:(RCTJavaScriptCompleteBlock)onComplete
+{
+  [_bridge enqueueApplicationScript:rawText url:url onComplete:onComplete];
+}
+
+@end