From 5a147f6335314defeed26c570ebcfe217e2af5d9 Mon Sep 17 00:00:00 2001
From: Jason Wray <jason@mapbox.com>
Date: Tue, 24 Apr 2018 20:32:43 -0400
Subject: [ios, macos] Fix possible retain cycles in blocks

Prompted by enabling CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF.
---
 platform/darwin/src/MGLMapSnapshotter.mm | 11 +++++++----
 platform/ios/src/MGLMapView.mm           | 14 +++++++++++---
 platform/macos/app/MapDocument.m         | 24 +++++++++++++++---------
 3 files changed, 33 insertions(+), 16 deletions(-)

diff --git a/platform/darwin/src/MGLMapSnapshotter.mm b/platform/darwin/src/MGLMapSnapshotter.mm
index 11a5442761..6449a7fd4f 100644
--- a/platform/darwin/src/MGLMapSnapshotter.mm
+++ b/platform/darwin/src/MGLMapSnapshotter.mm
@@ -122,8 +122,7 @@ const CGFloat MGLSnapshotterMinimumPixelSize = 64;
     _snapshotCallback = std::make_unique<mbgl::Actor<mbgl::MapSnapshotter::Callback>>(*mbgl::Scheduler::GetCurrent(), [=](std::exception_ptr mbglError, mbgl::PremultipliedImage image, mbgl::MapSnapshotter::Attributions attributions, mbgl::MapSnapshotter::PointForFn pointForFn) {
         __typeof__(self) strongSelf = weakSelf;
         strongSelf.loading = false;
-        
-        
+
         if (mbglError) {
             NSString *description = @(mbgl::util::toString(mbglError).c_str());
             NSDictionary *userInfo = @{NSLocalizedDescriptionKey: description};
@@ -145,9 +144,13 @@ const CGFloat MGLSnapshotterMinimumPixelSize = 64;
         }
         _snapshotCallback = NULL;
     });
-    dispatch_async(queue, ^{
-        _mbglMapSnapshotter->snapshot(_snapshotCallback->self());
 
+    dispatch_async(queue, ^{
+        __typeof__(self) strongSelf = weakSelf;
+        if (!strongSelf) {
+            return;
+        }
+        strongSelf->_mbglMapSnapshotter->snapshot(strongSelf->_snapshotCallback->self());
     });
 }
 
diff --git a/platform/ios/src/MGLMapView.mm b/platform/ios/src/MGLMapView.mm
index c679979d37..34269ce442 100644
--- a/platform/ios/src/MGLMapView.mm
+++ b/platform/ios/src/MGLMapView.mm
@@ -4570,6 +4570,8 @@ public:
         return;
     }
 
+    __weak __typeof__(self) weakSelf = self;
+
     // The user location callout view initially points to the user location
     // annotation’s implicit (visual) frame, which is offset from the
     // annotation’s explicit frame. Now the callout view needs to rendezvous
@@ -4583,10 +4585,16 @@ public:
                                  UIViewAnimationOptionBeginFromCurrentState)
                      animations:^
      {
+         __typeof__(self) strongSelf = weakSelf;
+         if ( ! strongSelf)
+         {
+             return;
+         }
+
          calloutView.frame = CGRectOffset(calloutView.frame,
-                                          _initialImplicitCalloutViewOffset.x,
-                                          _initialImplicitCalloutViewOffset.y);
-         _initialImplicitCalloutViewOffset = CGPointZero;
+                                          strongSelf->_initialImplicitCalloutViewOffset.x,
+                                          strongSelf->_initialImplicitCalloutViewOffset.y);
+         strongSelf->_initialImplicitCalloutViewOffset = CGPointZero;
      }
                      completion:NULL];
 }
diff --git a/platform/macos/app/MapDocument.m b/platform/macos/app/MapDocument.m
index 9b18dbd761..aee14c5c2f 100644
--- a/platform/macos/app/MapDocument.m
+++ b/platform/macos/app/MapDocument.m
@@ -93,9 +93,8 @@ NS_ARRAY_OF(id <MGLAnnotation>) *MBXFlattenedShapes(NS_ARRAY_OF(id <MGLAnnotatio
     BOOL _isTouringWorld;
     BOOL _isShowingPolygonAndPolylineAnnotations;
     BOOL _isShowingAnimatedAnnotation;
-    
-    // Snapshotter
-    MGLMapSnapshotter* snapshotter;
+
+    MGLMapSnapshotter *_snapshotter;
 }
 
 #pragma mark Lifecycle
@@ -185,17 +184,23 @@ NS_ARRAY_OF(id <MGLAnnotation>) *MBXFlattenedShapes(NS_ARRAY_OF(id <MGLAnnotatio
     options.zoomLevel = self.mapView.zoomLevel;
     
     // Create and start the snapshotter
-    snapshotter = [[MGLMapSnapshotter alloc] initWithOptions:options];
-    [snapshotter startWithCompletionHandler:^(MGLMapSnapshot *snapshot, NSError *error) {
+    __weak __typeof__(self) weakSelf = self;
+    _snapshotter = [[MGLMapSnapshotter alloc] initWithOptions:options];
+    [_snapshotter startWithCompletionHandler:^(MGLMapSnapshot *snapshot, NSError *error) {
+        __typeof__(self) strongSelf = weakSelf;
+        if (!strongSelf) {
+            return;
+        }
+
         if (error) {
             NSLog(@"Could not load snapshot: %@", error.localizedDescription);
         } else {
             // Set the default name for the file and show the panel.
             NSSavePanel *panel = [NSSavePanel savePanel];
-            panel.nameFieldStringValue = [self.mapView.styleURL.lastPathComponent.stringByDeletingPathExtension stringByAppendingPathExtension:@"png"];
+            panel.nameFieldStringValue = [strongSelf.mapView.styleURL.lastPathComponent.stringByDeletingPathExtension stringByAppendingPathExtension:@"png"];
             panel.allowedFileTypes = [@[(NSString *)kUTTypePNG] arrayByAddingObjectsFromArray:[NSBitmapImageRep imageUnfilteredTypes]];
             
-            [panel beginSheetModalForWindow:self.window completionHandler:^(NSInteger result) {
+            [panel beginSheetModalForWindow:strongSelf.window completionHandler:^(NSInteger result) {
                 if (result == NSFileHandlingPanelOKButton) {
                     // Write the contents in the new format.
                     NSURL *fileURL = panel.URL;
@@ -232,7 +237,8 @@ NS_ARRAY_OF(id <MGLAnnotation>) *MBXFlattenedShapes(NS_ARRAY_OF(id <MGLAnnotatio
             }];
 
         }
-        snapshotter = nil;
+
+        strongSelf->_snapshotter = nil;
     }];
 }
 
@@ -1179,7 +1185,7 @@ NS_ARRAY_OF(id <MGLAnnotation>) *MBXFlattenedShapes(NS_ARRAY_OF(id <MGLAnnotatio
         return YES;
     }
     if (menuItem.action == @selector(takeSnapshot:)) {
-        return !(snapshotter && [snapshotter isLoading]);
+        return !(_snapshotter && [_snapshotter isLoading]);
     }
     return NO;
 }
-- 
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