Merge pull request #179 from Unity-Technologies/zgh/build_scripts

fix: app crash because of animating gif

com.unity.uiwidgets/Runtime/painting/image_stream.cs

                 _emitFrame(new ImageInfo(image: _nextFrame.image, scale: _scale));
                 _shownTimestamp = timestamp;
                 _frameDuration = _nextFrame.duration;
+                _nextFrame.DisposeCPtr();
                 _nextFrame = null;
                 int completedCycles = _codec.frameCount == 0 ? 0 : _framesEmitted / _codec.frameCount;
 

com.unity.uiwidgets/Runtime/rendering/image.cs

                 if (value == _image) {
                     return;
                 }
-
+                if(_image != null){
+                    _image.DisposeCPtr();
+                }
                 _image = value;
                 markNeedsPaint();
                 if (_width == null || _height == null) {

com.unity.uiwidgets/Runtime/rendering/layer.cs

             get { return (ContainerLayer) base.parent; }
         }
 
+        public virtual void DisposeCPtr()
+        {
+            if(_engineLayer != null) {
+                _engineLayer.DisposeCPtr();
+            }
+        }
+
         public bool _needsAddToScene = true;
 
         protected void markNeedsAddToScene() {
         protected EngineLayer engineLayer {
             get { return _engineLayer; }
             set {
+                if(_engineLayer != null){
+                    _engineLayer.DisposeCPtr();
+                }
                 _engineLayer = value;
                 if (!alwaysNeedsAddToScene) {
                     if (parent != null && !parent.alwaysNeedsAddToScene) {
             this.canvasBounds = canvasBounds;
         }
 
+        public override void DisposeCPtr()
+        {
+            base.DisposeCPtr();
+            if(_picture != null){
+                 _picture.DisposeCPtr();
+            }
+        }
+
         public readonly Rect canvasBounds;
 
         Picture _picture;
             return addedLayers;
         }
 
+        public override void DisposeCPtr() {
+            base.DisposeCPtr();
+            Layer child = firstChild;
+            while (child != null) {
+                Layer next = child.nextSibling;
+                child.DisposeCPtr();
+                child = next;
+            }
+        }
+
         internal override void updateSubtreeNeedsAddToScene() {
             base.updateSubtreeNeedsAddToScene();
             Layer child = firstChild;
                 child._nextSibling = null;
                 D.assert(child.attached == attached);
                 dropChild(child);
+                child.DisposeCPtr();
                 child = next;
             }
 

com.unity.uiwidgets/Runtime/rendering/view.cs

             using (var scene = layer.buildScene(builder)) {
                 Window.instance.render(scene);
             }
-
+            builder.DisposeCPtr();
             D.assert(() => {
                 if (D.debugRepaintRainbowEnabled || D.debugRepaintTextRainbowEnabled) {
                     D.debugCurrentRepaintColor =

com.unity.uiwidgets/Runtime/ui/compositing.cs

         }
     }
 
-    public class SceneBuilder : NativeWrapper {
+    public class SceneBuilder : NativeWrapperCPtrDisposable {
-        public override void DisposePtr(IntPtr ptr) {
+        public override void DisposeCPtrImpl(IntPtr ptr) {
             SceneBuilder_dispose(ptr);
         }
 

com.unity.uiwidgets/Runtime/ui/native_bindings.cs

             _dispose();
         }
     }
+
+    /// <summary>
+    /// This class is used to release c++ resources in advance without waiting for c# garbage collection. 
+    /// Please make sure that the resource will not be used again after it is released.
+    /// Releasing resources prematurely may cause null pointer exceptions in references elsewhere.
+    ///
+    /// Usage: 
+    ///    Use DisposeCPtr() to manually release c++ resources, and then add an interface to release unmanaged memory 
+    ///    in DisposeCPtrImpl(IntPtr ptr).
+    /// </summary>
+    public abstract class NativeWrapperCPtrDisposable : NativeWrapperDisposable {
+        public bool isDisposed = false;
+
+        protected NativeWrapperCPtrDisposable() {
+        }
+
+        protected NativeWrapperCPtrDisposable(IntPtr ptr) : base(ptr) {
+        }
+
+        public void DisposeCPtr() {
+            DisposePtr(_ptr);
+        }
+        public override void DisposePtr(IntPtr ptr) {
+            if(isDisposed){
+                return;
+            }
+            isDisposed = true;
+            DisposeCPtrImpl(ptr); 
+        }
+
+        public abstract void DisposeCPtrImpl(IntPtr ptr);
+    }
 }

com.unity.uiwidgets/Runtime/ui/painting.cs

         public int rowBytes;
     }
 
-    public class Image : NativeWrapperDisposable, IEquatable<Image> {
+    public class Image : NativeWrapperCPtrDisposable, IEquatable<Image> {
+
-        public override void DisposePtr(IntPtr ptr) {
-            Image_dispose(ptr);
+        public override void DisposeCPtrImpl(IntPtr ptr) {
+            Image_dispose(ptr); 
         }
 
         public int width => Image_width(_ptr);
 
     public delegate void ImageDecoderCallback(Image result);
 
-    public class FrameInfo : NativeWrapper {
+    public class FrameInfo : NativeWrapperCPtrDisposable {
+        
-        public override void DisposePtr(IntPtr ptr) {
+        public override void DisposeCPtrImpl(IntPtr ptr) {
+
-        public Image image => new Image(FrameInfo_image(_ptr));
+        
+        private Image _image;
+
+        public Image image {
+            get {
+                if(_image == null){
+                    _image = new Image(FrameInfo_image(_ptr));
+                }
+                
+                return _image;
+            }
+        }
 
         [DllImport(NativeBindings.dllName)]
         static extern void FrameInfo_dispose(IntPtr ptr);
         reverseDifference,
     }
 
-    public abstract class EngineLayer : NativeWrapper {
+    public abstract class EngineLayer : NativeWrapperCPtrDisposable {
-        public override void DisposePtr(IntPtr ptr) {
+        public override void DisposeCPtrImpl(IntPtr ptr) {
             EngineLayer_dispose(ptr);
         }
 
             bool transparentOccluder);
     }
 
-    public class Picture : NativeWrapperDisposable {
+    public class Picture : NativeWrapperCPtrDisposable {
+
-        public override void DisposePtr(IntPtr ptr) {
+        public override void DisposeCPtrImpl(IntPtr ptr) {
             Picture_dispose(ptr);
         }
 

com.unity.uiwidgets/Runtime/widgets/widget_inspector.cs

         }
 
 
+        public override void DisposeCPtr() {
+            if(_picture != null){
+                _picture.DisposeCPtr();
+            }
+        }
+
         public override bool findAnnotations<S>(
             AnnotationResult<S> result,
             Offset localPosition,