Merge commit '7621e2f8dec938cf48181c8b10afc9b01f444e68' into beta

submodules/Display/Source/SimpleLayer.swift

@@ -0,0 +1,118 @@
+import UIKit
+
+public final class NullActionClass: NSObject, CAAction {
+    @objc public func run(forKey event: String, object anObject: Any, arguments dict: [AnyHashable : Any]?) {
+    }
+}
+
+public let nullAction = NullActionClass()
+
+open class SimpleLayer: CALayer {
+    public var didEnterHierarchy: (() -> Void)?
+    public var didExitHierarchy: (() -> Void)?
+    public private(set) var isInHierarchy: Bool = false
+    
+    override open func action(forKey event: String) -> CAAction? {
+        if event == kCAOnOrderIn {
+            self.isInHierarchy = true
+            self.didEnterHierarchy?()
+        } else if event == kCAOnOrderOut {
+            self.isInHierarchy = false
+            self.didExitHierarchy?()
+        }
+        return nullAction
+    }
+    
+    override public init() {
+        super.init()
+    }
+    
+    override public init(layer: Any) {
+        super.init(layer: layer)
+    }
+    
+    required public init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+}
+
+open class SimpleShapeLayer: CAShapeLayer {
+    public var didEnterHierarchy: (() -> Void)?
+    public var didExitHierarchy: (() -> Void)?
+    
+    override open func action(forKey event: String) -> CAAction? {
+        if event == kCAOnOrderIn {
+            self.didEnterHierarchy?()
+        } else if event == kCAOnOrderOut {
+            self.didExitHierarchy?()
+        }
+        return nullAction
+    }
+    
+    override public init() {
+        super.init()
+    }
+    
+    override public init(layer: Any) {
+        super.init(layer: layer)
+    }
+    
+    required public init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+}
+
+open class SimpleGradientLayer: CAGradientLayer {
+    public var didEnterHierarchy: (() -> Void)?
+    public var didExitHierarchy: (() -> Void)?
+    
+    override open func action(forKey event: String) -> CAAction? {
+        if event == kCAOnOrderIn {
+            self.didEnterHierarchy?()
+        } else if event == kCAOnOrderOut {
+            self.didExitHierarchy?()
+        }
+        return nullAction
+    }
+    
+    override public init() {
+        super.init()
+    }
+    
+    override public init(layer: Any) {
+        super.init(layer: layer)
+    }
+    
+    required public init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+}
+
+open class SimpleTransformLayer: CATransformLayer {
+    public var didEnterHierarchy: (() -> Void)?
+    public var didExitHierarchy: (() -> Void)?
+    public private(set) var isInHierarchy: Bool = false
+    
+    override open func action(forKey event: String) -> CAAction? {
+        if event == kCAOnOrderIn {
+            self.isInHierarchy = true
+            self.didEnterHierarchy?()
+        } else if event == kCAOnOrderOut {
+            self.isInHierarchy = false
+            self.didExitHierarchy?()
+        }
+        return nullAction
+    }
+    
+    override public init() {
+        super.init()
+    }
+    
+    override public init(layer: Any) {
+        super.init(layer: layer)
+    }
+    
+    required public init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+}