Ensured dismiss is possible when a popover is being presented and the other way around: both wait until the other operation is complete before starting the new transition.

werner77 · werner77 · commit 98a99cf4ee4d · 2017-04-25T10:08:45.000+02:00
diff --git a/Classes/Popover/NSCondition+WEPopover.h b/Classes/Popover/NSCondition+WEPopover.h
@@ -0,0 +1,35 @@
+//
+// Created by Werner Altewischer on 25/04/2017.
+// Copyright (c) 2017 Werner IT Consultancy. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+
+@interface NSCondition (WEPopover)
+
+/**
+ Waits in a background thread until the specified condition is broadcast/signalled and the specified predicate is true using appropriate thread safe locking techniques.
+
+ Using this method is assured that the wait stops when this object (self) is deallocated
+
+ Returns NO iff the predicate returned true without having to wait, YES if the wait actually had to occur.
+
+ @see broadcastCondition:forPredicateModification:
+ */
+- (BOOL)weWaitForPredicate:(BOOL (^)(void))predicate completion:(void (^)(BOOL waited))completion;
+
+/**
+ Waits with a timeout, specify timeout <= 0.0 to wait indefinitely.
+
+ The completion block has a BOOL argument predicateResult which is true if the predicate evaluated to true within the timeout period and false otherwise.
+
+ Returns NO iff the predicate returned true without having to wait, YES if the wait actually had to occur.
+ */
+- (BOOL)weWaitForPredicate:(BOOL (^)(void))predicate timeout:(NSTimeInterval)timeout completion:(void (^)(BOOL predicateResult, BOOL waited))completion;
+
+/**
+ Performs a thread safe predicate modification while broadcasting the condition which is paired to it.
+ */
+- (void)weBroadcastForPredicateModification:(void (^)(void))modification;
+
+@end
diff --git a/Classes/Popover/NSCondition+WEPopover.m b/Classes/Popover/NSCondition+WEPopover.m
@@ -0,0 +1,92 @@
+//
+// Created by Werner Altewischer on 25/04/2017.
+// Copyright (c) 2017 Werner IT Consultancy. All rights reserved.
+//
+
+#import "NSCondition+WEPopover.h"
+
+@implementation NSCondition (WEPopover)
+
+- (BOOL)weWaitForPredicate:(BOOL (^)(void))predicate completion:(void (^)(BOOL waited))completion {
+    return [self weWaitForPredicate:predicate timeout:0.0 completion:^(BOOL predicateResult, BOOL waited) {
+        if (completion) {
+            completion(waited);
+        }
+    }];
+}
+
+- (BOOL)weWaitForPredicate:(BOOL (^)(void))predicate timeout:(NSTimeInterval)timeout completion:(void (^)(BOOL predicateResult, BOOL waited))completion {
+    return [self weWaitForPredicate:predicate timeout:timeout completion:completion timeoutOccured:NO waited:NO];
+}
+
+- (BOOL)weWaitForPredicate:(BOOL (^)(void))predicate timeout:(NSTimeInterval)timeout completion:(void (^)(BOOL predicateEvaluation, BOOL waited))completion timeoutOccured:(BOOL)timeoutOccured waited:(BOOL)waited {
+
+    BOOL predicateResult = NO;
+
+    [self lock];
+    predicateResult = predicate();
+    [self unlock];
+
+    if (predicateResult || timeoutOccured) {
+        if (completion) {
+            completion(predicateResult, waited);
+        }
+        return NO;
+    } else {
+
+        NSDate *expirationDate = nil;
+        if (timeout > 0.0) {
+            expirationDate = [NSDate dateWithTimeIntervalSinceNow:timeout];
+        }
+
+        id __weak weakSelf = self;
+
+        [self wePerformBlockInBackground:^id {
+            BOOL predicateResult1 = NO;
+            [weakSelf lock];
+            while (weakSelf != nil && (predicateResult1 = predicate()) == NO && (expirationDate == nil || [expirationDate timeIntervalSinceNow] > 0.0)) {
+                if (expirationDate == nil) {
+                    //Wait for max 1 second to be able to check again if weakSelf != nil (object could be deallocated).
+                    [weakSelf waitUntilDate:[NSDate dateWithTimeIntervalSinceNow:1.0]];
+                } else {
+                    [weakSelf waitUntilDate:expirationDate];
+                }
+            }
+            [weakSelf unlock];
+            return @(predicateResult1);
+        }                 withCompletion:^(id resultFromBlock) {
+            BOOL timeoutOccured1 = ![resultFromBlock boolValue];
+            [weakSelf weWaitForPredicate:predicate timeout:timeout completion:completion timeoutOccured:timeoutOccured1 waited:YES];
+        }];
+        return YES;
+    }
+}
+
+/**
+ Performs a thread safe predicate modification while broadcasting the condition which is paired to it.
+ */
+- (void)weBroadcastForPredicateModification:(void (^)(void))modification {
+    [self lock];
+    modification();
+    [self broadcast];
+    [self unlock];
+}
+
+- (void)wePerformBlock:(id (^)(void))block onQueue:(dispatch_queue_t)queue withCompletion:(void (^)(id resultFromBlock))completion {
+    if (block) {
+        dispatch_async(queue, ^{
+            id result = block();
+            if (completion) {
+                dispatch_async(dispatch_get_main_queue(), ^{
+                    completion(result);
+                });
+            }
+        });
+    }
+}
+
+- (void)wePerformBlockInBackground:(id (^)(void))block withCompletion:(void (^)(id resultFromBlock))completion  {
+    [self wePerformBlock:block onQueue:dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0) withCompletion:completion];
+}
+
+@end
diff --git a/Classes/Popover/WEPopoverController.h b/Classes/Popover/WEPopoverController.h
@@ -136,6 +136,11 @@ typedef void(^WEPopoverTransitionBlock)(WEPopoverTransitionType transitionType,
  */
 @property (nonatomic, readonly, getter=isDismissing) BOOL dismissing;
 
+/**
+ * Convenience getter, returns true if presenting or dismissing.
+ */
+@property (nonatomic, readonly, getter=isTransitioning) BOOL transitioning;
+
 /**
  The view from which the popover was presented.
  
@@ -335,7 +340,8 @@ typedef void(^WEPopoverTransitionBlock)(WEPopoverTransitionType transitionType,
  
  The view and rect are used as anchor for automatic reposition during rotation.
  
- This method has no effect is the popover is already visible, being presented or dismissed.
+ This method has no effect is the popover is already visible.
+ If the popover is transitioning, this method waits untill the existing animation completes before starting the new presentation.
  */
 - (void)presentPopoverFromRect:(CGRect)rect
                         inView:(UIView *)view
@@ -346,7 +352,8 @@ typedef void(^WEPopoverTransitionBlock)(WEPopoverTransitionType transitionType,
 /**
  Presents the popover from the specified bar button item and allowed arrow directions, optionally animating the presentation.
  
- This method has no effect is the popover is already visible, being presented or dismissed.
+ This method has no effect is the popover is already visible.
+ If the popover is transitioning, this method waits untill the existing animation completes before starting the new presentation.
  */
 - (void)presentPopoverFromBarButtonItem:(UIBarButtonItem *)item
                permittedArrowDirections:(UIPopoverArrowDirection)arrowDirections
@@ -357,7 +364,8 @@ typedef void(^WEPopoverTransitionBlock)(WEPopoverTransitionType transitionType,
  
  Calls the completion block when done.
  
- This method has no effect is the popover is already visible, being presented or dismissed.
+ This method has no effect is the popover is already visible.
+ If the popover is transitioning, this method waits untill the existing animation completes before starting the new presentation.
  */
 - (void)presentPopoverFromBarButtonItem:(UIBarButtonItem *)item
                permittedArrowDirections:(UIPopoverArrowDirection)arrowDirections
@@ -369,7 +377,8 @@ typedef void(^WEPopoverTransitionBlock)(WEPopoverTransitionType transitionType,
  
  For more control, assign the contentViewController and call one of the other reposition methods manually.
  
- This method has no effect if the popover is currently dismissing or hasn't been presented yet.
+ This method has no effect if the popover hasn't been presented yet.
+ If the popover is transitioning, this method waits untill the existing animation completes before starting the new presentation.
  */
 - (void)repositionForContentViewController:(UIViewController *)vc animated:(BOOL)animated;
 
@@ -378,7 +387,8 @@ typedef void(^WEPopoverTransitionBlock)(WEPopoverTransitionType transitionType,
  
  The reposition is optionally animated.
  
- This method has no effect if the popover is currently dismissing or hasn't been presented yet.
+ This method has no effect if the popover hasn't been presented yet.
+ If the popover is transitioning, this method waits untill the existing animation completes before starting the new presentation.
  */
 - (void)repositionPopoverFromRect:(CGRect)rect
 						   inView:(UIView *)view
@@ -391,7 +401,8 @@ typedef void(^WEPopoverTransitionBlock)(WEPopoverTransitionType transitionType,
  The reposition is optionally animated.
  The completion block is called when done.
  
- This method has no effect if the popover is currently dismissing or hasn't been presented yet.
+ This method has no effect if the popover hasn't been presented yet.
+ If the popover is transitioning, this method waits untill the existing animation completes before starting the new presentation.
  */
 - (void)repositionPopoverFromRect:(CGRect)rect
                            inView:(UIView *)view
diff --git a/Classes/Popover/WEPopoverController.m b/Classes/Popover/WEPopoverController.m
@@ -13,6 +13,7 @@
 #import "WEPopoverContainerView.h"
 #import "WEWeakReference.h"
 #import "UIView+WEPopover.h"
+#import "NSCondition+WEPopover.h"
 
 static const NSTimeInterval kDefaultPrimaryAnimationDuration = 0.3;
 static const NSTimeInterval kDefaultSecundaryAnimationDuration = 0.15;
@@ -25,6 +26,7 @@ @interface WEPopoverController()<WETouchableViewDelegate>
 @property (nonatomic, assign, getter=isDismissing) BOOL dismissing;
 @property (nonatomic, assign, getter=isPopoverVisible) BOOL popoverVisible;
 @property (nonatomic, assign) CGSize effectivePopoverContentSize;
+@property (nonatomic, strong) NSCondition *transitioningCondition;
 
 @end
 
@@ -41,6 +43,7 @@ - (CGRect)collapsedFrameFromFrame:(CGRect)frame forArrowDirection:(UIPopoverArro
 - (UIView *)fillBackgroundViewWithDefault:(UIView *)defaultView;
 - (CGRect)calculatedContainerViewFrame;
 - (void)keyViewDidLayoutSubviewsNotification:(NSNotification *)notification;
+- (void)waitUntilNotTransitioningWithCompletion:(void (^)(BOOL waited))completion;
 
 @end
 
@@ -197,6 +200,7 @@ - (id)init {
         self.primaryAnimationDuration = kDefaultPrimaryAnimationDuration;
         self.secundaryAnimationDuration = kDefaultSecundaryAnimationDuration;
         self.gestureBlockingEnabled = YES;
+        self.transitioningCondition = [NSCondition new];
     }
     return self;
 }
@@ -214,6 +218,30 @@ - (void)dealloc {
 
 #pragma mark - Getters/setters
 
+- (void)setPresenting:(BOOL)presenting {
+    if (_presenting != presenting) {
+        [self.transitioningCondition weBroadcastForPredicateModification:^{
+            self->_presenting = presenting;
+        }];
+    }
+}
+
+- (void)setDismissing:(BOOL)dismissing {
+    if (_dismissing != dismissing) {
+        [self.transitioningCondition weBroadcastForPredicateModification:^{
+            self->_dismissing = dismissing;
+        }];
+    }
+}
+
+- (BOOL)transitioning {
+    return _presenting || _dismissing;
+}
+
+- (BOOL)isTransitioning {
+    return [self transitioning];
+}
+
 - (void)setContentViewController:(UIViewController *)vc {
     [self setContentViewController:vc animated:NO];
 }
@@ -330,6 +358,13 @@ - (void)presentPopoverFromRect:(CGRect)rect
                       animated:(BOOL)animated
                     completion:(WEPopoverCompletionBlock)completion {
 
+    if (self.isDismissing) {
+        __typeof(self) __weak weakSelf = self;
+        [self waitUntilNotTransitioningWithCompletion:^(BOOL waited) {
+            [weakSelf presentPopoverFromRect:rect inView:theView permittedArrowDirections:arrowDirections animated:animated completion:completion];
+        }];
+    }
+
     if (!self.isPresenting && !self.isDismissing && ![self isPopoverVisible]) {
         self.presenting = YES;
 
@@ -653,6 +688,14 @@ - (void)determineContentSizeWithConstraintSize:(CGSize)constraintSize {
 }
 
 - (void)dismissPopoverAnimated:(BOOL)animated userInitiated:(BOOL)userInitiated completion:(WEPopoverCompletionBlock)completion {
+
+    if (self.isPresenting) {
+        __typeof(self) __weak weakSelf = self;
+        [self waitUntilNotTransitioningWithCompletion:^(BOOL waited) {
+            [weakSelf dismissPopoverAnimated:animated userInitiated:userInitiated completion:completion];
+        }];
+    }
+
     if (self.containerView && !self.isDismissing && !self.isPresenting) {
         self.dismissing = YES;
         [self.containerView resignFirstResponder];
@@ -865,5 +908,16 @@ - (void)keyViewDidLayoutSubviewsNotification:(NSNotification *)notification {
     [self repositionContainerViewForFrameChange];
 }
 
+- (void)waitUntilNotTransitioningWithCompletion:(void (^)(BOOL waited))completion {
+    __typeof(self) __weak weakSelf = self;
+    [self.transitioningCondition weWaitForPredicate:^BOOL {
+        return !weakSelf.isTransitioning;
+    } completion:^(BOOL waited) {
+        if (completion) {
+            completion(waited);
+        }
+    }];
+}
+
 @end
 
diff --git a/WEPopover.xcodeproj/project.pbxproj b/WEPopover.xcodeproj/project.pbxproj
@@ -48,6 +48,7 @@
 		749FAE881286130000AB97F9 /* WEPopoverController.m in Sources */ = {isa = PBXBuildFile; fileRef = 749FAE841286130000AB97F9 /* WEPopoverController.m */; };
 		74A2A7B1190E5B800054A6CD /* QuartzCore.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 74A2A7B0190E5B800054A6CD /* QuartzCore.framework */; };
 		A83DF01A644BD2B58C4EDD65 /* WECustomPopoverController.m in Sources */ = {isa = PBXBuildFile; fileRef = A83DF4A31AA1332716629BF2 /* WECustomPopoverController.m */; };
+		A83DF0E72F611E8D79702E64 /* NSCondition+WEPopover.m in Sources */ = {isa = PBXBuildFile; fileRef = A83DF01961E14C5F2CE7865F /* NSCondition+WEPopover.m */; };
 		A83DF4665DCA1611146378A7 /* UIView+WEPopover.m in Sources */ = {isa = PBXBuildFile; fileRef = A83DFD2DCC3853D474CD9B5F /* UIView+WEPopover.m */; };
 /* End PBXBuildFile section */
 
@@ -108,6 +109,8 @@
 		749FAE851286130000AB97F9 /* WEPopoverParentView.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = WEPopoverParentView.h; sourceTree = "<group>"; };
 		74A2A7B0190E5B800054A6CD /* QuartzCore.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = QuartzCore.framework; path = System/Library/Frameworks/QuartzCore.framework; sourceTree = SDKROOT; };
 		8D1107310486CEB800E47090 /* WEPopover-Info.plist */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.plist.xml; path = "WEPopover-Info.plist"; plistStructureDefinitionIdentifier = "com.apple.xcode.plist.structure-definition.iphone.info-plist"; sourceTree = "<group>"; };
+		A83DF01961E14C5F2CE7865F /* NSCondition+WEPopover.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = "NSCondition+WEPopover.m"; sourceTree = "<group>"; };
+		A83DF062174D6D5F0B855E89 /* NSCondition+WEPopover.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "NSCondition+WEPopover.h"; sourceTree = "<group>"; };
 		A83DF428564B2075B045155A /* WECustomPopoverController.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = WECustomPopoverController.h; sourceTree = "<group>"; };
 		A83DF4A31AA1332716629BF2 /* WECustomPopoverController.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = WECustomPopoverController.m; sourceTree = "<group>"; };
 		A83DF7D277F13D75FAC228AD /* UIView+WEPopover.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "UIView+WEPopover.h"; sourceTree = "<group>"; };
@@ -261,6 +264,8 @@
 				749AF5581C7F553B00B444E1 /* WEWeakReference.m */,
 				A83DFD2DCC3853D474CD9B5F /* UIView+WEPopover.m */,
 				A83DF7D277F13D75FAC228AD /* UIView+WEPopover.h */,
+				A83DF01961E14C5F2CE7865F /* NSCondition+WEPopover.m */,
+				A83DF062174D6D5F0B855E89 /* NSCondition+WEPopover.h */,
 			);
 			path = Popover;
 			sourceTree = "<group>";
@@ -384,6 +389,7 @@
 				746B0A1D137454A000C5A8B5 /* UIBarButtonItem+WEPopover.m in Sources */,
 				A83DF01A644BD2B58C4EDD65 /* WECustomPopoverController.m in Sources */,
 				A83DF4665DCA1611146378A7 /* UIView+WEPopover.m in Sources */,
+				A83DF0E72F611E8D79702E64 /* NSCondition+WEPopover.m in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
