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// Copyright (c) 2006-2008 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 "chrome/browser/renderer_host/backing_store.h"
class RenderWidgetHost;
namespace {
typedef OwningMRUCache<RenderWidgetHost*, BackingStore*> BackingStoreCache;
static BackingStoreCache* cache = NULL;
// Returns the size of the backing store cache.
// TODO(iyengar) Make this dynamic, i.e. based on the available resources
// on the machine.
static int GetBackingStoreCacheSize() {
const int kMaxSize = 5;
return kMaxSize;
}
// Creates the backing store for the host based on the dimensions passed in.
// Removes the existing backing store if there is one.
BackingStore* CreateBackingStore(RenderWidgetHost* host,
const gfx::Rect& backing_store_rect) {
BackingStoreManager::RemoveBackingStore(host);
BackingStore* backing_store = new BackingStore(backing_store_rect.size());
int backing_store_cache_size = GetBackingStoreCacheSize();
if (backing_store_cache_size > 0) {
if (!cache)
cache = new BackingStoreCache(backing_store_cache_size);
cache->Put(host, backing_store);
}
return backing_store;
}
} // namespace
// BackingStoreManager ---------------------------------------------------------
// static
BackingStore* BackingStoreManager::GetBackingStore(
RenderWidgetHost* host,
const gfx::Size& desired_size) {
BackingStore* backing_store = Lookup(host);
if (backing_store) {
// If we already have a backing store, then make sure it is the correct
// size.
if (backing_store->size() == desired_size)
return backing_store;
backing_store = NULL;
}
return backing_store;
}
// static
BackingStore* BackingStoreManager::PrepareBackingStore(
RenderWidgetHost* host,
const gfx::Rect& backing_store_rect,
base::ProcessHandle process_handle,
HANDLE bitmap_section,
const gfx::Rect& bitmap_rect,
bool* needs_full_paint) {
BackingStore* backing_store = GetBackingStore(host,
backing_store_rect.size());
if (!backing_store) {
// We need to get Webkit to generate a new paint here, as we
// don't have a previous snapshot.
if (bitmap_rect != backing_store_rect) {
DCHECK(needs_full_paint != NULL);
*needs_full_paint = true;
}
backing_store = CreateBackingStore(host, backing_store_rect);
}
DCHECK(backing_store != NULL);
backing_store->PaintRect(process_handle, bitmap_section, bitmap_rect);
return backing_store;
}
// static
BackingStore* BackingStoreManager::Lookup(RenderWidgetHost* host) {
if (cache) {
BackingStoreCache::iterator it = cache->Peek(host);
if (it != cache->end())
return it->second;
}
return NULL;
}
// static
void BackingStoreManager::RemoveBackingStore(RenderWidgetHost* host) {
if (!cache)
return;
BackingStoreCache::iterator it = cache->Peek(host);
if (it == cache->end())
return;
cache->Erase(it);
if (cache->empty()) {
delete cache;
cache = NULL;
}
}
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