Revert "Revert 253606 "Revert 251238 "cc: Clean up iterator template to ...""

cc/layers/layer_iterator.cc

Index: cc/layers/layer_iterator.cc
diff --git a/cc/layers/layer_iterator.cc b/cc/layers/layer_iterator.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a52c3f1f39a1b89b71f838ca5d8deab7e20a92c4
--- /dev/null
+++ b/cc/layers/layer_iterator.cc
@@ -0,0 +1,130 @@
+// Copyright 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "cc/layers/layer_iterator.h"
+
+#include <vector>
+
+#include "cc/layers/layer.h"
+#include "cc/layers/layer_impl.h"
+#include "cc/layers/render_surface.h"
+#include "cc/layers/render_surface_impl.h"
+
+namespace cc {
+
+template <typename LayerType,
+          typename LayerList,
+          typename RenderSurfaceType,
+          typename ActionType>
+void LayerIteratorActions::FrontToBack::Begin(
+    LayerIterator<LayerType, LayerList, RenderSurfaceType, ActionType>* it) {
+  it->target_render_surface_layer_index_ = 0;
+  it->current_layer_index_ = it->target_render_surface_children().size() - 1;
+  GoToHighestInSubtree(it);
+}
+
+template <typename LayerType,
+          typename LayerList,
+          typename RenderSurfaceType,
+          typename ActionType>
+void LayerIteratorActions::FrontToBack::End(
+    LayerIterator<LayerType, LayerList, RenderSurfaceType, ActionType>* it) {
+  it->target_render_surface_layer_index_ =
+      LayerIteratorValue::kInvalidTargetRenderSurfaceLayerIndex;
+  it->current_layer_index_ = 0;
+}
+
+template <typename LayerType,
+          typename LayerList,
+          typename RenderSurfaceType,
+          typename ActionType>
+void LayerIteratorActions::FrontToBack::Next(
+    LayerIterator<LayerType, LayerList, RenderSurfaceType, ActionType>* it) {
+  // Moves to the previous layer in the current RS layer list.
+  // Then we check if the new current layer has its own RS,
+  // in which case there are things in that RS layer list that are higher,
+  // so we find the highest layer in that subtree.
+  // If we move back past the front of the list,
+  // we jump up to the previous RS layer list, picking up again where we
+  // had previously recursed into the current RS layer list.
+
+  if (!it->current_layer_represents_target_render_surface()) {
+    // Subtracting one here will eventually cause the current layer
+    // to become that layer representing the target render surface.
+    --it->current_layer_index_;
+    GoToHighestInSubtree(it);
+  } else {
+    while (it->current_layer_represents_target_render_surface()) {
+      if (!it->target_render_surface_layer_index_) {
+        // End of the list
+        it->target_render_surface_layer_index_ =
+            LayerIteratorValue::kInvalidTargetRenderSurfaceLayerIndex;
+        it->current_layer_index_ = 0;
+        return;
+      }
+      it->target_render_surface_layer_index_ = it->target_render_surface()
+          ->target_render_surface_layer_index_history_;
+      it->current_layer_index_ =
+          it->target_render_surface()->current_layer_index_history_;
+    }
+  }
+}
+
+template <typename LayerType,
+          typename LayerList,
+          typename RenderSurfaceType,
+          typename ActionType>
+void LayerIteratorActions::FrontToBack::GoToHighestInSubtree(
+    LayerIterator<LayerType, LayerList, RenderSurfaceType, ActionType>* it) {
+  if (it->current_layer_represents_target_render_surface())
+    return;
+  while (it->current_layer_represents_contributing_render_surface()) {
+    // Save where we were in the current target surface, move to the next one,
+    // and save the target surface that we came from there
+    // so we can go back to it.
+    it->target_render_surface()->current_layer_index_history_ =
+        it->current_layer_index_;
+    int previous_target_render_surface_layer =
+        it->target_render_surface_layer_index_;
+
+    for (LayerType* layer = it->current_layer();
+         it->target_render_surface_layer() != layer;
+         ++it->target_render_surface_layer_index_) {
+    }
+    it->current_layer_index_ = it->target_render_surface_children().size() - 1;
+
+    it->target_render_surface()->target_render_surface_layer_index_history_ =
+        previous_target_render_surface_layer;
+  }
+}
+
+// Declare each of the above functions for Layer and LayerImpl classes
+// so that they are linked.
+template CC_EXPORT void LayerIteratorActions::FrontToBack::Next(
+    LayerIterator<Layer, RenderSurfaceLayerList, RenderSurface, FrontToBack>*
+        it);
+template CC_EXPORT void LayerIteratorActions::FrontToBack::End(
+    LayerIterator<Layer, RenderSurfaceLayerList, RenderSurface, FrontToBack>*
+        it);
+template CC_EXPORT void LayerIteratorActions::FrontToBack::Begin(
+    LayerIterator<Layer, RenderSurfaceLayerList, RenderSurface, FrontToBack>*
+        it);
+template CC_EXPORT void LayerIteratorActions::FrontToBack::GoToHighestInSubtree(
+    LayerIterator<Layer, RenderSurfaceLayerList, RenderSurface, FrontToBack>*
+        it);
+
+template CC_EXPORT void LayerIteratorActions::FrontToBack::Next(
+    LayerIterator<LayerImpl, LayerImplList, RenderSurfaceImpl, FrontToBack>*
+        it);
+template CC_EXPORT void LayerIteratorActions::FrontToBack::End(
+    LayerIterator<LayerImpl, LayerImplList, RenderSurfaceImpl, FrontToBack>*
+        it);
+template CC_EXPORT void LayerIteratorActions::FrontToBack::Begin(
+    LayerIterator<LayerImpl, LayerImplList, RenderSurfaceImpl, FrontToBack>*
+        it);
+template CC_EXPORT void LayerIteratorActions::FrontToBack::GoToHighestInSubtree(
+    LayerIterator<LayerImpl, LayerImplList, RenderSurfaceImpl, FrontToBack>*
+        it);
+
+}  // namespace cc