src/cc/trees/tree_synchronizer.cc

   1 // Copyright 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "cc/trees/tree_synchronizer.h"
   6
   7 #include <set>
   8
   9 #include "base/containers/hash_tables.h"
  10 #include "base/containers/scoped_ptr_hash_map.h"
  11 #include "base/debug/trace_event.h"
  12 #include "base/logging.h"
  13 #include "cc/animation/scrollbar_animation_controller.h"
  14 #include "cc/input/scrollbar.h"
  15 #include "cc/layers/layer.h"
  16 #include "cc/layers/layer_impl.h"
  17 #include "cc/layers/scrollbar_layer_impl_base.h"
  18 #include "cc/layers/scrollbar_layer_interface.h"
  19
  20 namespace cc {
  21
  22 typedef base::ScopedPtrHashMap<int, LayerImpl> ScopedPtrLayerImplMap;
  23 typedef base::hash_map<int, LayerImpl*> RawPtrLayerImplMap;
  24
  25 void CollectExistingLayerImplRecursive(ScopedPtrLayerImplMap* old_layers,
  26                                        scoped_ptr<LayerImpl> layer_impl) {
  27   if (!layer_impl)
  28     return;
  29
  30   layer_impl->ClearScrollbars();
  31   if (ScrollbarLayerImplBase* scrollbar_layer =
  32           layer_impl->ToScrollbarLayer()) {
  33     scrollbar_layer->ClearClipLayer();
  34     scrollbar_layer->ClearScrollLayer();
  35   }
  36
  37   OwnedLayerImplList& children = layer_impl->children();
  38   for (OwnedLayerImplList::iterator it = children.begin();
  39        it != children.end();
  40        ++it)
  41     CollectExistingLayerImplRecursive(old_layers, children.take(it));
  42
  43   CollectExistingLayerImplRecursive(old_layers, layer_impl->TakeMaskLayer());
  44   CollectExistingLayerImplRecursive(old_layers, layer_impl->TakeReplicaLayer());
  45
  46   int id = layer_impl->id();
  47   old_layers->set(id, layer_impl.Pass());
  48 }
  49
  50 template <typename LayerType>
  51 scoped_ptr<LayerImpl> SynchronizeTreesInternal(
  52     LayerType* layer_root,
  53     scoped_ptr<LayerImpl> old_layer_impl_root,
  54     LayerTreeImpl* tree_impl) {
  55   DCHECK(tree_impl);
  56
  57   TRACE_EVENT0("cc", "TreeSynchronizer::SynchronizeTrees");
  58   ScopedPtrLayerImplMap old_layers;
  59   RawPtrLayerImplMap new_layers;
  60
  61   CollectExistingLayerImplRecursive(&old_layers, old_layer_impl_root.Pass());
  62
  63   scoped_ptr<LayerImpl> new_tree = SynchronizeTreesRecursive(
  64       &new_layers, &old_layers, layer_root, tree_impl);
  65
  66   UpdateScrollbarLayerPointersRecursive(&new_layers, layer_root);
  67
  68   return new_tree.Pass();
  69 }
  70
  71 scoped_ptr<LayerImpl> TreeSynchronizer::SynchronizeTrees(
  72     Layer* layer_root,
  73     scoped_ptr<LayerImpl> old_layer_impl_root,
  74     LayerTreeImpl* tree_impl) {
  75   return SynchronizeTreesInternal(
  76       layer_root, old_layer_impl_root.Pass(), tree_impl);
  77 }
  78
  79 scoped_ptr<LayerImpl> TreeSynchronizer::SynchronizeTrees(
  80     LayerImpl* layer_root,
  81     scoped_ptr<LayerImpl> old_layer_impl_root,
  82     LayerTreeImpl* tree_impl) {
  83   return SynchronizeTreesInternal(
  84       layer_root, old_layer_impl_root.Pass(), tree_impl);
  85 }
  86
  87 template <typename LayerType>
  88 scoped_ptr<LayerImpl> ReuseOrCreateLayerImpl(RawPtrLayerImplMap* new_layers,
  89                                              ScopedPtrLayerImplMap* old_layers,
  90                                              LayerType* layer,
  91                                              LayerTreeImpl* tree_impl) {
  92   scoped_ptr<LayerImpl> layer_impl = old_layers->take(layer->id());
  93
  94   if (!layer_impl)
  95     layer_impl = layer->CreateLayerImpl(tree_impl);
  96
  97   (*new_layers)[layer->id()] = layer_impl.get();
  98   return layer_impl.Pass();
  99 }
 100
 101 template <typename LayerType>
 102 scoped_ptr<LayerImpl> SynchronizeTreesRecursiveInternal(
 103     RawPtrLayerImplMap* new_layers,
 104     ScopedPtrLayerImplMap* old_layers,
 105     LayerType* layer,
 106     LayerTreeImpl* tree_impl) {
 107   if (!layer)
 108     return scoped_ptr<LayerImpl>();
 109
 110   scoped_ptr<LayerImpl> layer_impl =
 111       ReuseOrCreateLayerImpl(new_layers, old_layers, layer, tree_impl);
 112
 113   layer_impl->ClearChildList();
 114   for (size_t i = 0; i < layer->children().size(); ++i) {
 115     layer_impl->AddChild(SynchronizeTreesRecursiveInternal(
 116         new_layers, old_layers, layer->child_at(i), tree_impl));
 117   }
 118
 119   layer_impl->SetMaskLayer(SynchronizeTreesRecursiveInternal(
 120       new_layers, old_layers, layer->mask_layer(), tree_impl));
 121   layer_impl->SetReplicaLayer(SynchronizeTreesRecursiveInternal(
 122       new_layers, old_layers, layer->replica_layer(), tree_impl));
 123
 124   return layer_impl.Pass();
 125 }
 126
 127 scoped_ptr<LayerImpl> SynchronizeTreesRecursive(
 128     RawPtrLayerImplMap* new_layers,
 129     ScopedPtrLayerImplMap* old_layers,
 130     Layer* layer,
 131     LayerTreeImpl* tree_impl) {
 132   return SynchronizeTreesRecursiveInternal(
 133       new_layers, old_layers, layer, tree_impl);
 134 }
 135
 136 scoped_ptr<LayerImpl> SynchronizeTreesRecursive(
 137     RawPtrLayerImplMap* new_layers,
 138     ScopedPtrLayerImplMap* old_layers,
 139     LayerImpl* layer,
 140     LayerTreeImpl* tree_impl) {
 141   return SynchronizeTreesRecursiveInternal(
 142       new_layers, old_layers, layer, tree_impl);
 143 }
 144
 145 template <typename LayerType, typename ScrollbarLayerType>
 146 void UpdateScrollbarLayerPointersRecursiveInternal(
 147     const RawPtrLayerImplMap* new_layers,
 148     LayerType* layer) {
 149   if (!layer)
 150     return;
 151
 152   for (size_t i = 0; i < layer->children().size(); ++i) {
 153     UpdateScrollbarLayerPointersRecursiveInternal<
 154         LayerType, ScrollbarLayerType>(new_layers, layer->child_at(i));
 155   }
 156
 157   ScrollbarLayerType* scrollbar_layer = layer->ToScrollbarLayer();
 158   if (!scrollbar_layer)
 159     return;
 160
 161   RawPtrLayerImplMap::const_iterator iter =
 162       new_layers->find(layer->id());
 163   ScrollbarLayerImplBase* scrollbar_layer_impl =
 164       iter != new_layers->end()
 165           ? static_cast<ScrollbarLayerImplBase*>(iter->second)
 166           : NULL;
 167   DCHECK(scrollbar_layer_impl);
 168
 169   scrollbar_layer->PushScrollClipPropertiesTo(scrollbar_layer_impl);
 170 }
 171
 172 void UpdateScrollbarLayerPointersRecursive(const RawPtrLayerImplMap* new_layers,
 173                                            Layer* layer) {
 174   UpdateScrollbarLayerPointersRecursiveInternal<Layer, ScrollbarLayerInterface>(
 175       new_layers, layer);
 176 }
 177
 178 void UpdateScrollbarLayerPointersRecursive(const RawPtrLayerImplMap* new_layers,
 179                                            LayerImpl* layer) {
 180   UpdateScrollbarLayerPointersRecursiveInternal<
 181       LayerImpl,
 182       ScrollbarLayerImplBase>(new_layers, layer);
 183 }
 184
 185 // static
 186 template <typename LayerType>
 187 void TreeSynchronizer::PushPropertiesInternal(
 188     LayerType* layer,
 189     LayerImpl* layer_impl,
 190     size_t* num_dependents_need_push_properties_for_parent) {
 191   if (!layer) {
 192     DCHECK(!layer_impl);
 193     return;
 194   }
 195
 196   DCHECK_EQ(layer->id(), layer_impl->id());
 197
 198   bool push_layer = layer->needs_push_properties();
 199   bool recurse_on_children_and_dependents =
 200       layer->descendant_needs_push_properties();
 201
 202   if (push_layer)
 203     layer->PushPropertiesTo(layer_impl);
 204   else if (layer->ToScrollbarLayer())
 205     layer->ToScrollbarLayer()->PushScrollClipPropertiesTo(layer_impl);
 206
 207   size_t num_dependents_need_push_properties = 0;
 208   if (recurse_on_children_and_dependents) {
 209     PushPropertiesInternal(layer->mask_layer(),
 210                            layer_impl->mask_layer(),
 211                            &num_dependents_need_push_properties);
 212     PushPropertiesInternal(layer->replica_layer(),
 213                            layer_impl->replica_layer(),
 214                            &num_dependents_need_push_properties);
 215
 216     const OwnedLayerImplList& impl_children = layer_impl->children();
 217     DCHECK_EQ(layer->children().size(), impl_children.size());
 218
 219     for (size_t i = 0; i < layer->children().size(); ++i) {
 220       PushPropertiesInternal(layer->child_at(i),
 221                              impl_children[i],
 222                              &num_dependents_need_push_properties);
 223     }
 224
 225     // When PushPropertiesTo completes for a layer, it may still keep
 226     // its needs_push_properties() state if the layer must push itself
 227     // every PushProperties tree walk. Here we keep track of those layers, and
 228     // ensure that their ancestors know about them for the next PushProperties
 229     // tree walk.
 230     layer->num_dependents_need_push_properties_ =
 231         num_dependents_need_push_properties;
 232   }
 233
 234   bool add_self_to_parent = num_dependents_need_push_properties > 0 ||
 235                             layer->needs_push_properties();
 236   *num_dependents_need_push_properties_for_parent += add_self_to_parent ? 1 : 0;
 237 }
 238
 239 static void CheckScrollAndClipPointersRecursive(Layer* layer,
 240                                                 LayerImpl* layer_impl) {
 241   DCHECK_EQ(!!layer, !!layer_impl);
 242   if (!layer)
 243     return;
 244
 245   // Having a scroll parent on the impl thread implies having one the main
 246   // thread, too. The main thread may have a scroll parent that is not in the
 247   // tree because it's been removed but not deleted. In this case, the layer
 248   // impl will have no scroll parent. Same argument applies for clip parents and
 249   // scroll/clip children.
 250   DCHECK(!layer_impl->scroll_parent() || !!layer->scroll_parent());
 251   DCHECK(!layer_impl->clip_parent() || !!layer->clip_parent());
 252   DCHECK(!layer_impl->scroll_children() || !!layer->scroll_children());
 253   DCHECK(!layer_impl->clip_children() || !!layer->clip_children());
 254
 255   if (layer_impl->scroll_parent())
 256     DCHECK_EQ(layer->scroll_parent()->id(), layer_impl->scroll_parent()->id());
 257
 258   if (layer_impl->clip_parent())
 259     DCHECK_EQ(layer->clip_parent()->id(), layer_impl->clip_parent()->id());
 260
 261   if (layer_impl->scroll_children()) {
 262     for (std::set<Layer*>::iterator it = layer->scroll_children()->begin();
 263          it != layer->scroll_children()->end();
 264          ++it) {
 265       DCHECK_EQ((*it)->scroll_parent(), layer);
 266     }
 267     for (std::set<LayerImpl*>::iterator it =
 268              layer_impl->scroll_children()->begin();
 269          it != layer_impl->scroll_children()->end();
 270          ++it) {
 271       DCHECK_EQ((*it)->scroll_parent(), layer_impl);
 272     }
 273   }
 274
 275   if (layer_impl->clip_children()) {
 276     for (std::set<Layer*>::iterator it = layer->clip_children()->begin();
 277          it != layer->clip_children()->end();
 278          ++it) {
 279       DCHECK_EQ((*it)->clip_parent(), layer);
 280     }
 281     for (std::set<LayerImpl*>::iterator it =
 282              layer_impl->clip_children()->begin();
 283          it != layer_impl->clip_children()->end();
 284          ++it) {
 285       DCHECK_EQ((*it)->clip_parent(), layer_impl);
 286     }
 287   }
 288
 289   for (size_t i = 0u; i < layer->children().size(); ++i) {
 290     CheckScrollAndClipPointersRecursive(layer->child_at(i),
 291                                         layer_impl->child_at(i));
 292   }
 293 }
 294
 295 void TreeSynchronizer::PushProperties(Layer* layer,
 296                                       LayerImpl* layer_impl) {
 297   size_t num_dependents_need_push_properties = 0;
 298   PushPropertiesInternal(
 299       layer, layer_impl, &num_dependents_need_push_properties);
 300 #if DCHECK_IS_ON
 301   CheckScrollAndClipPointersRecursive(layer, layer_impl);
 302 #endif
 303 }
 304
 305 void TreeSynchronizer::PushProperties(LayerImpl* layer, LayerImpl* layer_impl) {
 306   size_t num_dependents_need_push_properties = 0;
 307   PushPropertiesInternal(
 308       layer, layer_impl, &num_dependents_need_push_properties);
 309 }
 310
 311 }  // namespace cc