SurfaceFlinger: Use traversal functions to iterate LayerList.
In preparation for the Layer hierarchy. There we will need
to use such a style to traverse the tree of layers.
Test: Just a refactoring. SurfaceFlinger still works.
Change-Id: I84dcd82e713f1bdbe911658793ce11460267a956
diff --git a/services/surfaceflinger/LayerVector.h b/services/surfaceflinger/LayerVector.h
new file mode 100644
index 0000000..7dfa4a0
--- /dev/null
+++ b/services/surfaceflinger/LayerVector.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_SURFACE_FLINGER_LAYER_VECTOR_H
+#define ANDROID_SURFACE_FLINGER_LAYER_VECTOR_H
+
+#include <utils/SortedVector.h>
+#include <utils/RefBase.h>
+
+#include <functional>
+
+namespace android {
+class Layer;
+
+/*
+ * Used by the top-level SurfaceFlinger state and individual layers
+ * to track layers they own sorted according to Z-order. Provides traversal
+ * functions for traversing all owned layers, and their descendents.
+ */
+class LayerVector : public SortedVector<sp<Layer>> {
+public:
+ LayerVector() = default;
+ LayerVector(const LayerVector& rhs);
+ // Sorts layer by layer-stack, Z order, and finally creation order (sequence).
+ int do_compare(const void* lhs, const void* rhs) const override;
+
+ void traverseInReverseZOrder(const std::function<void(Layer*)>& consume) const;
+ void traverseInZOrder(const std::function<void(Layer*)>& consume) const;
+};
+}
+
+#endif /* ANDROID_SURFACE_FLINGER_LAYER_VECTOR_H_ */