[ios] Potential fix for over retain/release issues with adding layers to styles. Integration tests run on device.

2 files changed, 17 insertions, 3 deletions

diff --git a/platform/darwin/src/MGLOpenGLStyleLayer.mm b/platform/darwin/src/MGLOpenGLStyleLayer.mm
index 8933a77382..9f957b7082 100644
--- a/platform/darwin/src/MGLOpenGLStyleLayer.mm
+++ b/platform/darwin/src/MGLOpenGLStyleLayer.mm
@@ -15,7 +15,11 @@
     when creating an OpenGL style layer.
  */
 void MGLPrepareCustomStyleLayer(void *context) {
-    MGLOpenGLStyleLayer *layer = (__bridge MGLOpenGLStyleLayer *)context;
+
+    // Pair retain/release during rendering (see MGLFinishCustomStyleLayer)
+    id retaineee = (__bridge id)context;
+    MGLOpenGLStyleLayer *layer = (__bridge MGLOpenGLStyleLayer*)CFBridgingRetain(retaineee);
+
     [layer didMoveToMapView:layer.style.mapView];
 }
 
@@ -47,7 +51,8 @@ void MGLDrawCustomStyleLayer(void *context, const mbgl::style::CustomLayerRender
     when creating an OpenGL style layer.
  */
 void MGLFinishCustomStyleLayer(void *context) {
-    MGLOpenGLStyleLayer *layer = (__bridge_transfer MGLOpenGLStyleLayer *)context;
+    // Release the layer (since we retained it in the initialization)
+    MGLOpenGLStyleLayer *layer = CFBridgingRelease(context);
     [layer willMoveFromMapView:layer.style.mapView];
 }
 
@@ -97,11 +102,12 @@ void MGLFinishCustomStyleLayer(void *context) {
  @return An initialized OpenGL style layer.
  */
 - (instancetype)initWithIdentifier:(NSString *)identifier {
+    // Note, do not retain self here, otherwise MGLOpenGLStyleLayer will never be dealloc'd
     auto layer = std::make_unique<mbgl::style::CustomLayer>(identifier.UTF8String,
                                                             MGLPrepareCustomStyleLayer,
                                                             MGLDrawCustomStyleLayer,
                                                             MGLFinishCustomStyleLayer,
-                                                            (__bridge_retained void *)self);
+                                                            (__bridge void*)self);
     return self = [super initWithPendingLayer:std::move(layer)];
 }
 
diff --git a/platform/darwin/src/MGLStyleLayer.mm b/platform/darwin/src/MGLStyleLayer.mm
index 6400b8fcbf..2a70cab563 100644
--- a/platform/darwin/src/MGLStyleLayer.mm
+++ b/platform/darwin/src/MGLStyleLayer.mm
@@ -38,6 +38,10 @@
                     "to the style more than once is invalid.", self, style];
     }
 
+    // Since we're adding self to a C++ collection, we need to retain ourselves, so that we don't
+    // end up with a dangling pointer
+    CFBridgingRetain(self);
+
     if (otherLayer) {
         const mbgl::optional<std::string> belowLayerId{otherLayer.identifier.UTF8String};
         style.rawStyle->addLayer(std::move(_pendingLayer), belowLayerId);
@@ -51,6 +55,10 @@
     if (self.rawLayer == style.rawStyle->getLayer(self.identifier.UTF8String)) {
         _pendingLayer = style.rawStyle->removeLayer(self.identifier.UTF8String);
     }
+
+    // Pair the retain above, and release self, since we're now removed from the collection
+    CFTypeRef toRelease = (__bridge CFTypeRef)self;
+    CFBridgingRelease(toRelease);
 }
 
 - (void)setVisible:(BOOL)visible