Define the delay for '-[XCUIApplicationProcess setEventLoopHasIdled:]…

…' with a desiredCapability (#140)

WebDriverAgent.xcodeproj/project.pbxproj

@@ -462,6 +462,7 @@
 		1FC3B2E12121EC8C00B61EE0 /* FBApplicationProcessProxyTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = FBApplicationProcessProxyTests.m; sourceTree = "<group>"; };
 		44757A831D42CE8300ECF35E /* XCUIDeviceRotationTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = XCUIDeviceRotationTests.m; sourceTree = "<group>"; };
 		631B523421F6174300625362 /* FBImageIOScalerTests.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = FBImageIOScalerTests.m; sourceTree = "<group>"; };
+		633E904A220DEE7F007CADF9 /* XCUIApplicationProcessDelay.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = XCUIApplicationProcessDelay.h; sourceTree = "<group>"; };
 		6385F4A5220A40760095BBDB /* XCUIApplicationProcessDelay.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = XCUIApplicationProcessDelay.m; sourceTree = "<group>"; };
 		63CCF91021ECE4C700E94ABD /* FBImageIOScaler.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = FBImageIOScaler.h; sourceTree = "<group>"; };
 		63CCF91121ECE4C700E94ABD /* FBImageIOScaler.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = FBImageIOScaler.m; sourceTree = "<group>"; };
@@ -1172,6 +1173,7 @@
 				EE6B64FC1D0F86EF00E85F5D /* XCTestPrivateSymbols.m */,
 				63CCF91021ECE4C700E94ABD /* FBImageIOScaler.h */,
 				63CCF91121ECE4C700E94ABD /* FBImageIOScaler.m */,
+				633E904A220DEE7F007CADF9 /* XCUIApplicationProcessDelay.h */,
 				6385F4A5220A40760095BBDB /* XCUIApplicationProcessDelay.m */,
 			);
 			name = Utilities;

WebDriverAgent.xcodeproj/xcshareddata/xcschemes/WebDriverAgentRunner.xcscheme

@@ -85,11 +85,6 @@
             value = "$(WDA_PRODUCT_BUNDLE_IDENTIFIER)"
             isEnabled = "YES">
          </EnvironmentVariable>
-         <EnvironmentVariable
-            key = "EVENTLOOP_IDLE_DELAY_SEC"
-            value = "0"
-            isEnabled = "YES">
-         </EnvironmentVariable>
       </EnvironmentVariables>
       <AdditionalOptions>
       </AdditionalOptions>

WebDriverAgentLib/Commands/FBSessionCommands.m

@@ -18,6 +18,7 @@
 #import "XCUIDevice.h"
 #import "XCUIDevice+FBHealthCheck.h"
 #import "XCUIDevice+FBHelpers.h"
+#import "XCUIApplicationProcessDelay.h"
 
 static NSString* const USE_COMPACT_RESPONSES = @"shouldUseCompactResponses";
 static NSString* const ELEMENT_RESPONSE_ATTRIBUTES = @"elementResponseAttributes";
@@ -92,6 +93,12 @@ + (NSArray *)routes
   if (requirements[@"shouldUseSingletonTestManager"]) {
     [FBConfiguration setShouldUseSingletonTestManager:[requirements[@"shouldUseSingletonTestManager"] boolValue]];
   }
+  NSNumber *delay = requirements[@"eventloopIdleDelaySec"];
+  if ([delay doubleValue] > 0.0) {
+    [XCUIApplicationProcessDelay setEventLoopHasIdledDelay:[delay doubleValue]];
+  } else {
+    [XCUIApplicationProcessDelay disableEventLoopDelay];
+  }
 
   [FBConfiguration setShouldWaitForQuiescence:[requirements[@"shouldWaitForQuiescence"] boolValue]];
 

WebDriverAgentLib/Utilities/XCUIApplicationProcessDelay.h

@@ -0,0 +1,38 @@
+/**
+ * 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>
+
+NS_ASSUME_NONNULL_BEGIN
+
+/**
+ In certain cases WebDriverAgent fails to create a session because -[XCUIApplication launch] doesn't return
+ since it waits for the target app to be quiescenced.
+ The reason for this seems to be that 'testmanagerd' doesn't send the events WebDriverAgent is waiting for.
+ The expected events would trigger calls to '-[XCUIApplicationProcess setEventLoopHasIdled:]' and
+ '-[XCUIApplicationProcess setAnimationsHaveFinished:]', which are the properties that are checked to
+ determine whether an app has quiescenced or not.
+ Delaying the call to on of the setters can fix this issue.
+ */
+@interface XCUIApplicationProcessDelay : NSObject
+
+/**
+ Delays the invocation of '-[XCUIApplicationProcess setEventLoopHasIdled:]' by the timer interval passed
+ @param delay The duration of the sleep before the original method is called
+ */
++ (void)setEventLoopHasIdledDelay:(NSTimeInterval)delay;
+
+/**
+ Disables the delayed invocation of '-[XCUIApplicationProcess setEventLoopHasIdled:]'.
+ */
++ (void)disableEventLoopDelay;
+
+@end
+
+NS_ASSUME_NONNULL_END

WebDriverAgentLib/Utilities/XCUIApplicationProcessDelay.m

@@ -7,44 +7,49 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  */
 
+#import "XCUIApplicationProcessDelay.h"
 #import <objc/runtime.h>
 #import "XCUIApplicationProcess.h"
 #import "FBLogger.h"
 
-/**
- In certain cases WebDriverAgent fails to create a session because -[XCUIApplication launch] doesn't return
- since it waits for the target app to be quiescenced.
- The reason for this seems to be that 'testmanagerd' doesn't send the events WebDriverAgent is waiting for.
- The expected events would trigger calls to '-[XCUIApplicationProcess setEventLoopHasIdled:]' and
- '-[XCUIApplicationProcess setAnimationsHaveFinished:]', which are the properties that are checked to
- determine whether an app has quiescenced or not.
- Delaying the call to on of the setters can fix this issue. Setting the environment variable
- 'EVENTLOOP_IDLE_DELAY_SEC' will swizzle the method '-[XCUIApplicationProcess setEventLoopHasIdled:]'
- and add a thread sleep of the value specified in the environment variable in seconds.
- */
-@interface XCUIApplicationProcessDelay : NSObject
-
-@end
-
-static NSString *const EVENTLOOP_IDLE_DELAY_SEC = @"EVENTLOOP_IDLE_DELAY_SEC";
 static void (*orig_set_event_loop_has_idled)(id, SEL, BOOL);
-static NSTimeInterval delay = 0;
+static NSTimeInterval eventloopIdleDelay = 0;
+static BOOL isSwizzled = NO;
+// '-[XCUIApplicationProcess setEventLoopHasIdled:]' can be called from different queues.
+// Lets lock the setup and access to the 'eventloopIdleDelay' variable
+static NSLock * lock = nil;
 
 @implementation XCUIApplicationProcessDelay
 
 + (void)load {
-  NSDictionary *env = [[NSProcessInfo processInfo] environment];
-  NSString *setEventLoopIdleDelay = [env objectForKey:EVENTLOOP_IDLE_DELAY_SEC];
-  if (!setEventLoopIdleDelay || [setEventLoopIdleDelay length] == 0) {
-    [FBLogger verboseLog:@"don't delay -[XCUIApplicationProcess setEventLoopHasIdled:]"];
+  lock = [[NSLock alloc] init];
+}
+
++ (void)setEventLoopHasIdledDelay:(NSTimeInterval)delay
+{
+  [lock lock];
+  if (!isSwizzled && delay < DBL_EPSILON) {
+    // don't swizzle methods until we need to
+    [lock unlock];
     return;
   }
-  delay = [setEventLoopIdleDelay doubleValue];
-  if (delay < DBL_EPSILON) {
-    [FBLogger log:[NSString stringWithFormat:@"Value of '%@' has to be greater than zero to delay -[XCUIApplicationProcess setEventLoopHasIdled:]",
-                   EVENTLOOP_IDLE_DELAY_SEC]];
+  eventloopIdleDelay = delay;
+  if (isSwizzled) {
+    [lock unlock];
     return;
   }
+  [self swizzleSetEventLoopHasIdled];
+  [lock unlock];
+}
+
++ (void)disableEventLoopDelay
+{
+  // Once the methods were swizzled they stay like that since the only change in the implementation
+  // is the thread sleep, which is skipped on setting it to zero.
+  [self setEventLoopHasIdledDelay:0];
+}
+
++ (void)swizzleSetEventLoopHasIdled {
   Method original = class_getInstanceMethod([XCUIApplicationProcess class], @selector(setEventLoopHasIdled:));
   if (original == nil) {
     [FBLogger log:@"Could not find method -[XCUIApplicationProcess setEventLoopHasIdled:]"];
@@ -53,11 +58,17 @@ + (void)load {
   orig_set_event_loop_has_idled = (void(*)(id, SEL, BOOL)) method_getImplementation(original);
   Method replace = class_getClassMethod([XCUIApplicationProcessDelay class], @selector(setEventLoopHasIdled:));
   method_setImplementation(original, method_getImplementation(replace));
+  isSwizzled = YES;
 }
 
 + (void)setEventLoopHasIdled:(BOOL)idled {
-  [FBLogger verboseLog:[NSString stringWithFormat:@"Delaying -[XCUIApplicationProcess setEventLoopHasIdled:] by %.2f seconds", delay]];
-  [NSThread sleepForTimeInterval:delay];
+  [lock lock];
+  NSTimeInterval delay = eventloopIdleDelay;
+  [lock unlock];
+  if (delay > 0.0) {
+    [FBLogger verboseLog:[NSString stringWithFormat:@"Delaying -[XCUIApplicationProcess setEventLoopHasIdled:] by %.2f seconds", delay]];
+    [NSThread sleepForTimeInterval:delay];
+  }
   orig_set_event_loop_has_idled(self, _cmd, idled);
 }