cc: Mirror LiveTilesRect and tiles between active and recycled trees.

cc/resources/picture_layer_tiling.cc

 // 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/resources/picture_layer_tiling.h"
 
 #include <algorithm>
 #include <cmath>
 #include <limits>
 #include <set>
@@ skipping 101 matching lines @@
   tiling_data_.SetMaxTextureSize(tile_size);
 }
 
 PictureLayerTiling::~PictureLayerTiling() {
   for (TileMap::const_iterator it = tiles_.begin(); it != tiles_.end(); ++it)
     it->second->set_shared(false);
 }
 
 Tile* PictureLayerTiling::CreateTile(int i,
                                      int j,
-                                     const PictureLayerTiling* twin_tiling) {
+                                     const PictureLayerTiling* twin_tiling,
+                                     PictureLayerTiling* recycled_twin) {
+  // Can't have both a (pending or active) twin and a recycled twin tiling.
+  DCHECK_IMPLIES(twin_tiling, !recycled_twin);
+  DCHECK_IMPLIES(recycled_twin, !twin_tiling);
   TileMapKey key(i, j);
   DCHECK(tiles_.find(key) == tiles_.end());
 
   gfx::Rect paint_rect = tiling_data_.TileBoundsWithBorder(i, j);
   gfx::Rect tile_rect = paint_rect;
   tile_rect.set_size(tiling_data_.max_texture_size());
 
   // Check our twin for a valid tile.
   if (twin_tiling &&
       tiling_data_.max_texture_size() ==
@@ skipping 12 matching lines @@
       }
     }
   }
 
   // Create a new tile because our twin didn't have a valid one.
   scoped_refptr<Tile> tile = client_->CreateTile(this, tile_rect);
   if (tile.get()) {
     DCHECK(!tile->is_shared());
     tile->set_tiling_index(i, j);
     tiles_[key] = tile;
+
+    if (recycled_twin) {
+      DCHECK(recycled_twin->tiles_.find(key) == recycled_twin->tiles_.end());
+      // Do what recycled_twin->CreateTile() would do.
+      tile->set_shared(true);
+      recycled_twin->tiles_[key] = tile;
+    }
   }
   eviction_tiles_cache_valid_ = false;
   return tile.get();
 }
 
 void PictureLayerTiling::CreateMissingTilesInLiveTilesRect() {
   const PictureLayerTiling* twin_tiling =
       client_->GetPendingOrActiveTwinTiling(this);
+  // There is no recycled twin during commit from the main thread which is when
+  // this occurs.
+  PictureLayerTiling* null_recycled_twin = nullptr;
+  DCHECK_EQ(null_recycled_twin, client_->GetRecycledTwinTiling(this));
   bool include_borders = false;
   for (TilingData::Iterator iter(
            &tiling_data_, live_tiles_rect_, include_borders);
        iter;
        ++iter) {
     TileMapKey key = iter.index();
     TileMap::iterator find = tiles_.find(key);
     if (find != tiles_.end())
       continue;
-    CreateTile(key.first, key.second, twin_tiling);
+    CreateTile(key.first, key.second, twin_tiling, null_recycled_twin);
   }
 
-  VerifyLiveTilesRect();
+  VerifyLiveTilesRect(false);
 }
 
 void PictureLayerTiling::CloneTilesAndPropertiesFrom(
     const PictureLayerTiling& twin_tiling) {
   DCHECK_EQ(&twin_tiling, client_->GetPendingOrActiveTwinTiling(this));
 
   Resize(twin_tiling.layer_bounds_);
   DCHECK_EQ(twin_tiling.contents_scale_, contents_scale_);
   DCHECK_EQ(twin_tiling.layer_bounds().ToString(), layer_bounds().ToString());
   DCHECK_EQ(twin_tiling.tile_size().ToString(), tile_size().ToString());
 
   resolution_ = twin_tiling.resolution_;
 
   SetLiveTilesRect(twin_tiling.live_tiles_rect());
 
   // Recreate unshared tiles.
   std::vector<TileMapKey> to_remove;
   for (const auto& tile_map_pair : tiles_) {
     TileMapKey key = tile_map_pair.first;
     Tile* tile = tile_map_pair.second.get();
     if (!tile->is_shared())
       to_remove.push_back(key);
   }
   // The recycled twin does not exist since there is a pending twin (which is
   // |twin_tiling|).
   PictureLayerTiling* null_recycled_twin = nullptr;
   DCHECK_EQ(null_recycled_twin, client_->GetRecycledTwinTiling(this));
   for (const auto& key : to_remove) {
     RemoveTileAt(key.first, key.second, null_recycled_twin);
-    CreateTile(key.first, key.second, &twin_tiling);
+    CreateTile(key.first, key.second, &twin_tiling, null_recycled_twin);
+  }
+
+  // Create any missing tiles from the |twin_tiling|.
+  for (const auto& tile_map_pair : twin_tiling.tiles_) {

[danakj, 2014/12/30 16:44:58]

1 here: We walk all pending tiles, and if they are not shared, create an active
tile that is shared.

[danakj, 2014/12/30 16:46:28]

Or maybe since we know the tile will be shared we should do this more cheaply,
like how we create a tile for the recycled twin, without needing to compare
invalidation, scale rects, and such.

[vmpstr, 2014/12/30 17:16:55]

You mean when we're creating the pending tile, if it's not shared but should be,
we set it immediately on the active tree? That seems a bit messy, since it's
like a pre-activation activation since the raster source on that tile has to be
the pending source... Alternatively we could somehow maintain a set of tile
indexes that should be created but are not due to client not creating the tile.

Something like 
... tile = client_->CreateTile(...)
if (tile) {
 ...
} else {
 want_but_dont_have_tile.insert(index);
}

Although I can already see that can be a major pain to maintain...

[danakj, 2014/12/30 17:20:47]

I mean like instead of

CreateTile(key, foo bar, twin, etc);

tile->set_shared(true);
tiles_[key] = tile;

Avoids the math/virtuals in CreateTile. 

[vmpstr, 2014/12/30 18:03:58]

Oh I see, but still keep the loop here? That could work, although I'm not sure
it will save enough.

+    TileMapKey key = tile_map_pair.first;
+    Tile* tile = tile_map_pair.second.get();
+    if (!tile->is_shared())
+      CreateTile(key.first, key.second, &twin_tiling, null_recycled_twin);
   }
 
   DCHECK_EQ(twin_tiling.tiles_.size(), tiles_.size());
 #if DCHECK_IS_ON
   for (const auto& tile_map_pair : tiles_)
     DCHECK(tile_map_pair.second->is_shared());
+  VerifyLiveTilesRect(false);
 #endif
 
   UpdateTilePriorityRects(twin_tiling.current_content_to_screen_scale_,
                           twin_tiling.current_visible_rect_,
                           twin_tiling.current_skewport_rect_,
                           twin_tiling.current_soon_border_rect_,
                           twin_tiling.current_eventually_rect_,
                           twin_tiling.current_occlusion_in_layer_space_);
 }
 
@@ skipping 48 matching lines @@
   int after_bottom = -1;
   if (!live_tiles_rect_.IsEmpty()) {
     after_right =
         tiling_data_.TileXIndexFromSrcCoord(live_tiles_rect_.right() - 1);
     after_bottom =
         tiling_data_.TileYIndexFromSrcCoord(live_tiles_rect_.bottom() - 1);
   }
 
   // There is no recycled twin since this is run on the pending tiling
   // during commit, and on the active tree during activate.
-  PictureLayerTiling* recycled_twin = NULL;
-  DCHECK_EQ(recycled_twin, client_->GetRecycledTwinTiling(this));
+  PictureLayerTiling* null_recycled_twin = nullptr;
+  DCHECK_EQ(null_recycled_twin, client_->GetRecycledTwinTiling(this));
 
   // Drop tiles outside the new layer bounds if the layer shrank.
   for (int i = after_right + 1; i <= before_right; ++i) {
     for (int j = before_top; j <= before_bottom; ++j)
-      RemoveTileAt(i, j, recycled_twin);
+      RemoveTileAt(i, j, null_recycled_twin);
   }
   for (int i = before_left; i <= after_right; ++i) {
     for (int j = after_bottom + 1; j <= before_bottom; ++j)
-      RemoveTileAt(i, j, recycled_twin);
+      RemoveTileAt(i, j, null_recycled_twin);
   }
 
   // If the layer grew, the live_tiles_rect_ is not changed, but a new row
   // and/or column of tiles may now exist inside the same live_tiles_rect_.
   const PictureLayerTiling* twin_tiling =
       client_->GetPendingOrActiveTwinTiling(this);
   if (after_right > before_right) {
     DCHECK_EQ(after_right, before_right + 1);
     for (int j = before_top; j <= after_bottom; ++j)
-      CreateTile(after_right, j, twin_tiling);
+      CreateTile(after_right, j, twin_tiling, null_recycled_twin);
   }
   if (after_bottom > before_bottom) {
     DCHECK_EQ(after_bottom, before_bottom + 1);
     for (int i = before_left; i <= before_right; ++i)
-      CreateTile(i, after_bottom, twin_tiling);
+      CreateTile(i, after_bottom, twin_tiling, null_recycled_twin);
   }
 }
 
 void PictureLayerTiling::Invalidate(const Region& layer_invalidation) {
   if (live_tiles_rect_.IsEmpty())
     return;
   std::vector<TileMapKey> new_tile_keys;
   gfx::Rect expanded_live_tiles_rect =
       tiling_data_.ExpandRectIgnoringBordersToTileBounds(live_tiles_rect_);
   for (Region::Iterator iter(layer_invalidation); iter.has_rect();
@@ skipping 13 matching lines @@
       continue;
     // Since the content_rect includes border pixels already, don't include
     // borders when iterating to avoid double counting them.
     bool include_borders = false;
     for (TilingData::Iterator iter(
              &tiling_data_, content_rect, include_borders);
          iter;
          ++iter) {
       // There is no recycled twin for the pending tree during commit, or for
       // the active tree during activation.
-      PictureLayerTiling* null_recycled_twin = NULL;
+      PictureLayerTiling* null_recycled_twin = nullptr;
       DCHECK_EQ(null_recycled_twin, client_->GetRecycledTwinTiling(this));
       if (RemoveTileAt(iter.index_x(), iter.index_y(), null_recycled_twin))
         new_tile_keys.push_back(iter.index());
     }
   }
 
   if (!new_tile_keys.empty()) {
     // During commit from the main thread, invalidations can never be shared
     // with the active tree since the active tree has different content there.
-    const PictureLayerTiling* twin_tiling = nullptr;
+    // And when invalidating an active-tree tiling, it means there was no
+    // pending tiling to clone from.
+    const PictureLayerTiling* null_twin_tiling = nullptr;
+    PictureLayerTiling* null_recycled_twin = nullptr;
+    DCHECK_EQ(null_recycled_twin, client_->GetRecycledTwinTiling(this));
     for (size_t i = 0; i < new_tile_keys.size(); ++i) {
-      CreateTile(new_tile_keys[i].first, new_tile_keys[i].second, twin_tiling);
+      CreateTile(new_tile_keys[i].first, new_tile_keys[i].second,
+                 null_twin_tiling, null_recycled_twin);
     }
   }
 }
 
 void PictureLayerTiling::SetRasterSource(
     scoped_refptr<RasterSource> raster_source) {
   // Shared (ie. non-invalidated) tiles on the pending tree are updated to use
   // the new raster source. When this raster source is activated, the raster
   // source will remain valid for shared tiles in the active tree.
   for (TileMap::const_iterator it = tiles_.begin(); it != tiles_.end(); ++it)
     it->second->set_raster_source(raster_source);
-  VerifyLiveTilesRect();
+  VerifyLiveTilesRect(false);
 }
 
 PictureLayerTiling::CoverageIterator::CoverageIterator()
     : tiling_(NULL),
       current_tile_(NULL),
       tile_i_(0),
       tile_j_(0),
       left_(0),
       top_(0),
       right_(-1),
@@ skipping 142 matching lines @@
 bool PictureLayerTiling::RemoveTileAt(int i,
                                       int j,
                                       PictureLayerTiling* recycled_twin) {
   TileMap::iterator found = tiles_.find(TileMapKey(i, j));
   if (found == tiles_.end())
     return false;
   found->second->set_shared(false);
   tiles_.erase(found);
   eviction_tiles_cache_valid_ = false;
   if (recycled_twin) {
-    // Recycled twin does not also have a recycled twin, so pass NULL.
-    recycled_twin->RemoveTileAt(i, j, NULL);
+    // Recycled twin does not also have a recycled twin, so pass null.
+    recycled_twin->RemoveTileAt(i, j, nullptr);
   }
   return true;
 }
 
 void PictureLayerTiling::Reset() {
   live_tiles_rect_ = gfx::Rect();
   PictureLayerTiling* recycled_twin = client_->GetRecycledTwinTiling(this);
   for (TileMap::const_iterator it = tiles_.begin(); it != tiles_.end(); ++it) {
     it->second->set_shared(false);
     if (recycled_twin)
-      recycled_twin->RemoveTileAt(it->first.first, it->first.second, NULL);
+      recycled_twin->RemoveTileAt(it->first.first, it->first.second, nullptr);
   }
   tiles_.clear();
   eviction_tiles_cache_valid_ = false;
 }
 
 gfx::Rect PictureLayerTiling::ComputeSkewport(
     double current_frame_time_in_seconds,
     const gfx::Rect& visible_rect_in_content_space) const {
   gfx::Rect skewport = visible_rect_in_content_space;
   if (last_impl_frame_time_in_seconds_ == 0.0)
@@ skipping 122 matching lines @@
 
 void PictureLayerTiling::SetLiveTilesRect(
     const gfx::Rect& new_live_tiles_rect) {
   DCHECK(new_live_tiles_rect.IsEmpty() ||
          gfx::Rect(tiling_size()).Contains(new_live_tiles_rect))
       << "tiling_size: " << tiling_size().ToString()
       << " new_live_tiles_rect: " << new_live_tiles_rect.ToString();
   if (live_tiles_rect_ == new_live_tiles_rect)
     return;
 
+  PictureLayerTiling* recycled_twin = client_->GetRecycledTwinTiling(this);
+
   // Iterate to delete all tiles outside of our new live_tiles rect.
-  PictureLayerTiling* recycled_twin = client_->GetRecycledTwinTiling(this);
   for (TilingData::DifferenceIterator iter(&tiling_data_,
                                            live_tiles_rect_,
                                            new_live_tiles_rect);
        iter;
        ++iter) {
     RemoveTileAt(iter.index_x(), iter.index_y(), recycled_twin);
   }
 
   const PictureLayerTiling* twin_tiling =
       client_->GetPendingOrActiveTwinTiling(this);
 
   // Iterate to allocate new tiles for all regions with newly exposed area.
   for (TilingData::DifferenceIterator iter(&tiling_data_,
                                            new_live_tiles_rect,
                                            live_tiles_rect_);
        iter;
        ++iter) {
     TileMapKey key(iter.index());
-    CreateTile(key.first, key.second, twin_tiling);
+    CreateTile(key.first, key.second, twin_tiling, recycled_twin);

[danakj, 2014/12/30 16:44:58]

2 here: We create and add a tile to the recycled tiling's hash map.

   }
 
   live_tiles_rect_ = new_live_tiles_rect;
-  VerifyLiveTilesRect();
+  VerifyLiveTilesRect(false);
+  if (recycled_twin) {
+    recycled_twin->live_tiles_rect_ = live_tiles_rect_;
+    recycled_twin->VerifyLiveTilesRect(true);
+  }
 }
 
-void PictureLayerTiling::VerifyLiveTilesRect() {
+void PictureLayerTiling::VerifyLiveTilesRect(bool is_on_recycle_tree) const {

[vmpstr, 2014/12/12 20:10:32]

hah, nice.

 #if DCHECK_IS_ON
-  for (TileMap::iterator it = tiles_.begin(); it != tiles_.end(); ++it) {
+  for (auto it = tiles_.begin(); it != tiles_.end(); ++it) {
     if (!it->second.get())
       continue;
     DCHECK(it->first.first < tiling_data_.num_tiles_x())
         << this << " " << it->first.first << "," << it->first.second
         << " num_tiles_x " << tiling_data_.num_tiles_x() << " live_tiles_rect "
         << live_tiles_rect_.ToString();
     DCHECK(it->first.second < tiling_data_.num_tiles_y())
         << this << " " << it->first.first << "," << it->first.second
         << " num_tiles_y " << tiling_data_.num_tiles_y() << " live_tiles_rect "
         << live_tiles_rect_.ToString();
     DCHECK(tiling_data_.TileBounds(it->first.first, it->first.second)
                .Intersects(live_tiles_rect_))
         << this << " " << it->first.first << "," << it->first.second
         << " tile bounds "
         << tiling_data_.TileBounds(it->first.first, it->first.second).ToString()
         << " live_tiles_rect " << live_tiles_rect_.ToString();
+    DCHECK_IMPLIES(is_on_recycle_tree, it->second->is_shared());
   }
 #endif
 }
 
 bool PictureLayerTiling::IsTileOccluded(const Tile* tile) const {
   DCHECK(tile);
 
   if (!current_occlusion_in_layer_space_.HasOcclusion())
     return false;
 
@@ skipping 530 matching lines @@
     }
     current_tile_ = tiling_->TileAt(next_index.first, next_index.second);
   }
 
   if (current_tile_)
     tiling_->UpdateTileAndTwinPriority(current_tile_);
   return *this;
 }
 
 }  // namespace cc