[ios, macos] Layer ownership refactor (#6904)

`MGLStyleLayer` was updated to support a raw pointer to the mbgl object, which is always initialized, either to the  value returned by `mbgl::Map getLayer`, or for independently created objects,  to the pointer value held in `pendingLayer`. In the latter case, this raw  pointer value stays even after ownership of the object is transferred via  `mbgl::Map addLayer`.

1 files changed, 59 insertions, 34 deletions

diff --git a/platform/darwin/src/MGLLineStyleLayer.mm b/platform/darwin/src/MGLLineStyleLayer.mm
index 57724a0600..aa699ea37d 100644
--- a/platform/darwin/src/MGLLineStyleLayer.mm
+++ b/platform/darwin/src/MGLLineStyleLayer.mm
@@ -2,6 +2,7 @@
 // Edit platform/darwin/scripts/generate-style-code.js, then run `make style-code-darwin`.
 
 #import "MGLSource.h"
+#import "MGLMapView_Private.h"
 #import "NSPredicate+MGLAdditions.h"
 #import "MGLStyleLayer_Private.h"
 #import "MGLStyleValue_Private.h"
@@ -11,80 +12,86 @@
 
 @interface MGLLineStyleLayer ()
 
-@property (nonatomic) mbgl::style::LineLayer *layer;
+@property (nonatomic) mbgl::style::LineLayer *rawLayer;
 
 @end
 
 @implementation MGLLineStyleLayer
+{
+    std::unique_ptr<mbgl::style::LineLayer> _pendingLayer;
+}
 
 - (instancetype)initWithIdentifier:(NSString *)identifier source:(MGLSource *)source
 {
     if (self = [super initWithIdentifier:identifier source:source]) {
-        _layer = new mbgl::style::LineLayer(identifier.UTF8String, source.identifier.UTF8String);
+        auto layer = std::make_unique<mbgl::style::LineLayer>(identifier.UTF8String, source.identifier.UTF8String);
+        _pendingLayer = std::move(layer);
+        self.rawLayer = _pendingLayer.get();
     }
     return self;
 }
 
+
 - (NSString *)sourceLayerIdentifier
 {
-    auto layerID = self.layer->getSourceLayer();
+    auto layerID = self.rawLayer->getSourceLayer();
     return layerID.empty() ? nil : @(layerID.c_str());
 }
 
 - (void)setSourceLayerIdentifier:(NSString *)sourceLayerIdentifier
 {
-    self.layer->setSourceLayer(sourceLayerIdentifier.UTF8String ?: "");
+    self.rawLayer->setSourceLayer(sourceLayerIdentifier.UTF8String ?: "");
 }
 
 - (void)setPredicate:(NSPredicate *)predicate
 {
-    self.layer->setFilter(predicate.mgl_filter);
+    self.rawLayer->setFilter(predicate.mgl_filter);
 }
 
 - (NSPredicate *)predicate
 {
-    return [NSPredicate mgl_predicateWithFilter:self.layer->getFilter()];
+    return [NSPredicate mgl_predicateWithFilter:self.rawLayer->getFilter()];
 }
 
 #pragma mark - Accessing the Layout Attributes
 
 - (void)setLineCap:(MGLStyleValue<NSValue *> *)lineCap {
     auto mbglValue = MGLStyleValueTransformer<mbgl::style::LineCapType, NSValue *>().toPropertyValue(lineCap);
-    self.layer->setLineCap(mbglValue);
+    self.rawLayer->setLineCap(mbglValue);
 }
 
 - (MGLStyleValue<NSValue *> *)lineCap {
-    auto propertyValue = self.layer->getLineCap() ?: self.layer->getDefaultLineCap();
+    auto propertyValue = self.rawLayer->getLineCap() ?: self.rawLayer->getDefaultLineCap();
     return MGLStyleValueTransformer<mbgl::style::LineCapType, NSValue *>().toStyleValue(propertyValue);
 }
 
 - (void)setLineJoin:(MGLStyleValue<NSValue *> *)lineJoin {
     auto mbglValue = MGLStyleValueTransformer<mbgl::style::LineJoinType, NSValue *>().toPropertyValue(lineJoin);
-    self.layer->setLineJoin(mbglValue);
+    self.rawLayer->setLineJoin(mbglValue);
 }
 
 - (MGLStyleValue<NSValue *> *)lineJoin {
-    auto propertyValue = self.layer->getLineJoin() ?: self.layer->getDefaultLineJoin();
+    auto propertyValue = self.rawLayer->getLineJoin() ?: self.rawLayer->getDefaultLineJoin();
     return MGLStyleValueTransformer<mbgl::style::LineJoinType, NSValue *>().toStyleValue(propertyValue);
 }
 
 - (void)setLineMiterLimit:(MGLStyleValue<NSNumber *> *)lineMiterLimit {
     auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(lineMiterLimit);
-    self.layer->setLineMiterLimit(mbglValue);
+    self.rawLayer->setLineMiterLimit(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)lineMiterLimit {
-    auto propertyValue = self.layer->getLineMiterLimit() ?: self.layer->getDefaultLineMiterLimit();
+    auto propertyValue = self.rawLayer->getLineMiterLimit() ?: self.rawLayer->getDefaultLineMiterLimit();
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
 - (void)setLineRoundLimit:(MGLStyleValue<NSNumber *> *)lineRoundLimit {
     auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(lineRoundLimit);
-    self.layer->setLineRoundLimit(mbglValue);
+    self.rawLayer->setLineRoundLimit(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)lineRoundLimit {
-    auto propertyValue = self.layer->getLineRoundLimit() ?: self.layer->getDefaultLineRoundLimit();
+    auto propertyValue = self.rawLayer->getLineRoundLimit() ?: self.rawLayer->getDefaultLineRoundLimit();
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
@@ -92,102 +99,120 @@
 
 - (void)setLineOpacity:(MGLStyleValue<NSNumber *> *)lineOpacity {
     auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(lineOpacity);
-    self.layer->setLineOpacity(mbglValue);
+    self.rawLayer->setLineOpacity(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)lineOpacity {
-    auto propertyValue = self.layer->getLineOpacity() ?: self.layer->getDefaultLineOpacity();
+    auto propertyValue = self.rawLayer->getLineOpacity() ?: self.rawLayer->getDefaultLineOpacity();
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
 - (void)setLineColor:(MGLStyleValue<MGLColor *> *)lineColor {
     auto mbglValue = MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toPropertyValue(lineColor);
-    self.layer->setLineColor(mbglValue);
+    self.rawLayer->setLineColor(mbglValue);
 }
 
 - (MGLStyleValue<MGLColor *> *)lineColor {
-    auto propertyValue = self.layer->getLineColor() ?: self.layer->getDefaultLineColor();
+    auto propertyValue = self.rawLayer->getLineColor() ?: self.rawLayer->getDefaultLineColor();
     return MGLStyleValueTransformer<mbgl::Color, MGLColor *>().toStyleValue(propertyValue);
 }
 
 - (void)setLineTranslate:(MGLStyleValue<NSValue *> *)lineTranslate {
     auto mbglValue = MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toPropertyValue(lineTranslate);
-    self.layer->setLineTranslate(mbglValue);
+    self.rawLayer->setLineTranslate(mbglValue);
 }
 
 - (MGLStyleValue<NSValue *> *)lineTranslate {
-    auto propertyValue = self.layer->getLineTranslate() ?: self.layer->getDefaultLineTranslate();
+    auto propertyValue = self.rawLayer->getLineTranslate() ?: self.rawLayer->getDefaultLineTranslate();
     return MGLStyleValueTransformer<std::array<float, 2>, NSValue *>().toStyleValue(propertyValue);
 }
 
 - (void)setLineTranslateAnchor:(MGLStyleValue<NSValue *> *)lineTranslateAnchor {
     auto mbglValue = MGLStyleValueTransformer<mbgl::style::TranslateAnchorType, NSValue *>().toPropertyValue(lineTranslateAnchor);
-    self.layer->setLineTranslateAnchor(mbglValue);
+    self.rawLayer->setLineTranslateAnchor(mbglValue);
 }
 
 - (MGLStyleValue<NSValue *> *)lineTranslateAnchor {
-    auto propertyValue = self.layer->getLineTranslateAnchor() ?: self.layer->getDefaultLineTranslateAnchor();
+    auto propertyValue = self.rawLayer->getLineTranslateAnchor() ?: self.rawLayer->getDefaultLineTranslateAnchor();
     return MGLStyleValueTransformer<mbgl::style::TranslateAnchorType, NSValue *>().toStyleValue(propertyValue);
 }
 
 - (void)setLineWidth:(MGLStyleValue<NSNumber *> *)lineWidth {
     auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(lineWidth);
-    self.layer->setLineWidth(mbglValue);
+    self.rawLayer->setLineWidth(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)lineWidth {
-    auto propertyValue = self.layer->getLineWidth() ?: self.layer->getDefaultLineWidth();
+    auto propertyValue = self.rawLayer->getLineWidth() ?: self.rawLayer->getDefaultLineWidth();
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
 - (void)setLineGapWidth:(MGLStyleValue<NSNumber *> *)lineGapWidth {
     auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(lineGapWidth);
-    self.layer->setLineGapWidth(mbglValue);
+    self.rawLayer->setLineGapWidth(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)lineGapWidth {
-    auto propertyValue = self.layer->getLineGapWidth() ?: self.layer->getDefaultLineGapWidth();
+    auto propertyValue = self.rawLayer->getLineGapWidth() ?: self.rawLayer->getDefaultLineGapWidth();
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
 - (void)setLineOffset:(MGLStyleValue<NSNumber *> *)lineOffset {
     auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(lineOffset);
-    self.layer->setLineOffset(mbglValue);
+    self.rawLayer->setLineOffset(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)lineOffset {
-    auto propertyValue = self.layer->getLineOffset() ?: self.layer->getDefaultLineOffset();
+    auto propertyValue = self.rawLayer->getLineOffset() ?: self.rawLayer->getDefaultLineOffset();
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
 - (void)setLineBlur:(MGLStyleValue<NSNumber *> *)lineBlur {
     auto mbglValue = MGLStyleValueTransformer<float, NSNumber *>().toPropertyValue(lineBlur);
-    self.layer->setLineBlur(mbglValue);
+    self.rawLayer->setLineBlur(mbglValue);
 }
 
 - (MGLStyleValue<NSNumber *> *)lineBlur {
-    auto propertyValue = self.layer->getLineBlur() ?: self.layer->getDefaultLineBlur();
+    auto propertyValue = self.rawLayer->getLineBlur() ?: self.rawLayer->getDefaultLineBlur();
     return MGLStyleValueTransformer<float, NSNumber *>().toStyleValue(propertyValue);
 }
 
 - (void)setLineDasharray:(MGLStyleValue<NSArray<NSNumber *> *> *)lineDasharray {
     auto mbglValue = MGLStyleValueTransformer<std::vector<float>, NSArray<NSNumber *> *, float>().toPropertyValue(lineDasharray);
-    self.layer->setLineDasharray(mbglValue);
+    self.rawLayer->setLineDasharray(mbglValue);
 }
 
 - (MGLStyleValue<NSArray<NSNumber *> *> *)lineDasharray {
-    auto propertyValue = self.layer->getLineDasharray() ?: self.layer->getDefaultLineDasharray();
+    auto propertyValue = self.rawLayer->getLineDasharray() ?: self.rawLayer->getDefaultLineDasharray();
     return MGLStyleValueTransformer<std::vector<float>, NSArray<NSNumber *> *, float>().toStyleValue(propertyValue);
 }
 
 - (void)setLinePattern:(MGLStyleValue<NSString *> *)linePattern {
     auto mbglValue = MGLStyleValueTransformer<std::string, NSString *>().toPropertyValue(linePattern);
-    self.layer->setLinePattern(mbglValue);
+    self.rawLayer->setLinePattern(mbglValue);
 }
 
 - (MGLStyleValue<NSString *> *)linePattern {
-    auto propertyValue = self.layer->getLinePattern() ?: self.layer->getDefaultLinePattern();
+    auto propertyValue = self.rawLayer->getLinePattern() ?: self.rawLayer->getDefaultLinePattern();
     return MGLStyleValueTransformer<std::string, NSString *>().toStyleValue(propertyValue);
 }
 
+
+#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