[ios, macos] Take back source and layer ownership on removal (#7048)

If a source or layer is removed from the style, recapture the
unique pointer ownership. This makes it safe to add back sources
and layers after they have been removed.

1 files changed, 25 insertions, 17 deletions

diff --git a/platform/darwin/src/MGLStyleLayer.mm.ejs b/platform/darwin/src/MGLStyleLayer.mm.ejs
index 48d013d482..d366a1955b 100644
--- a/platform/darwin/src/MGLStyleLayer.mm.ejs
+++ b/platform/darwin/src/MGLStyleLayer.mm.ejs
@@ -73,6 +73,31 @@
 }
 
 <% } -%>
+
+#pragma mark -  Adding to and removing from a map view
+
+- (void)addToMapView:(MGLMapView *)mapView
+{
+    [self addToMapView:mapView belowLayer:nil];
+}
+
+- (void)addToMapView:(MGLMapView *)mapView belowLayer:(MGLStyleLayer *)otherLayer
+{
+    if (otherLayer) {
+        const mbgl::optional<std::string> belowLayerId{otherLayer.identifier.UTF8String};
+        mapView.mbglMap->addLayer(std::move(_pendingLayer), belowLayerId);
+    } else {
+        mapView.mbglMap->addLayer(std::move(_pendingLayer));
+    }
+}
+
+- (void)removeFromMapView:(MGLMapView *)mapView
+{
+    auto removedLayer = mapView.mbglMap->removeLayer(self.identifier.UTF8String);
+    _pendingLayer = std::move(reinterpret_cast<std::unique_ptr<mbgl::style::<%- camelize(type) %>Layer> &>(removedLayer));
+    self.rawLayer = _pendingLayer.get();
+}
+
 <% if (layoutProperties.length) { -%>
 #pragma mark - Accessing the Layout Attributes
 
@@ -106,21 +131,4 @@
 <% } -%>
 <% } -%>
 
-#pragma mark - Add style layer to map
-
-- (void)addToMapView:(MGLMapView *)mapView
-{
-    [self addToMapView:mapView belowLayer:nil];
-}
-
-- (void)addToMapView:(MGLMapView *)mapView belowLayer:(MGLStyleLayer *)otherLayer
-{
-    if (otherLayer) {
-        const mbgl::optional<std::string> belowLayerId{otherLayer.identifier.UTF8String};
-        mapView.mbglMap->addLayer(std::move(_pendingLayer), belowLayerId);
-    } else {
-        mapView.mbglMap->addLayer(std::move(_pendingLayer));
-    }
-}
-
 @end