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.cpp b/services/surfaceflinger/LayerVector.cpp
new file mode 100644
index 0000000..6ac4b14
--- /dev/null
+++ b/services/surfaceflinger/LayerVector.cpp
@@ -0,0 +1,55 @@
+/*
+ * 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.
+ */
+
+#include "LayerVector.h"
+#include "Layer.h"
+
+namespace android {
+LayerVector::LayerVector(const LayerVector& rhs) : SortedVector<sp<Layer>>(rhs) {
+}
+
+int LayerVector::do_compare(const void* lhs, const void* rhs) const
+{
+ // sort layers per layer-stack, then by z-order and finally by sequence
+ const auto& l = *reinterpret_cast<const sp<Layer>*>(lhs);
+ const auto& r = *reinterpret_cast<const sp<Layer>*>(rhs);
+
+ uint32_t ls = l->getCurrentState().layerStack;
+ uint32_t rs = r->getCurrentState().layerStack;
+ if (ls != rs)
+ return ls - rs;
+
+ uint32_t lz = l->getCurrentState().z;
+ uint32_t rz = r->getCurrentState().z;
+ if (lz != rz)
+ return lz - rz;
+
+ return l->sequence - r->sequence;
+}
+
+void LayerVector::traverseInZOrder(const std::function<void(Layer*)>& consume) const {
+ const size_t n = size();
+ for (size_t i = 0; i < n; i++) {
+ consume((*this)[i].get());
+ }
+}
+
+void LayerVector::traverseInReverseZOrder(const std::function<void(Layer*)>& consume) const {
+ for (auto i = static_cast<int64_t>(size()) - 1; i >= 0; i--) {
+ consume((*this)[i].get());
+ }
+}
+} // namespace android