android: add ThumbnailCache

chrome/browser/android/thumbnail_cache.h

+// Copyright 2014 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.
+
+#ifndef CHROME_BROWSER_ANDROID_THUMBNAIL_CACHE_H_
+#define CHROME_BROWSER_ANDROID_THUMBNAIL_CACHE_H_
+
+#include <list>
+#include <set>
+#include <string>
+
+#include "base/bind.h"
+#include "base/containers/hash_tables.h"
+#include "base/files/file_path.h"
+#include "base/memory/ref_counted.h"
+#include "base/threading/thread.h"
+#include "base/time/time.h"
+#include "content/public/browser/android/ui_resource_listener.h"
+#include "content/public/browser/android/ui_resource_provider.h"
+#include "net/base/linked_hash_map.h"
+#include "skia/ext/refptr.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+#include "ui/gfx/geometry/point.h"
+#include "ui/gfx/geometry/size.h"
+#include "ui/gfx/geometry/size_f.h"
+#include "url/gurl.h"
+
+class SkBitmap;
+class TabThumbnailProvider;
+
+namespace base {
+class File;
+class Time;
+}
+
+namespace content {
+class ContentViewCore;
+class UIResourceProvider;
+}
+
+typedef int TabId;
+typedef std::list<TabId> TabIdList;
+
+class ThumbnailChangeListener {
+ public:
+  virtual void OnThumbnailChanged(TabId tab_id, bool upgrade) = 0;
+  virtual void OnUIResourceUpdated(TabId tab_id,
+                                   cc::UIResourceId ui_resource_id,
+                                   gfx::Size content_size,
+                                   gfx::SizeF scaled_thumbnail_size) = 0;
+};
+
+class ThumbnailCache : public content::UIResourceListener {
+ private:
+  class Thumbnail : public base::RefCountedThreadSafe<Thumbnail> {
+   public:
+    enum ThumbnailFormat { DECOMPRESSED, COMPRESSED };
+
+    // This constructs a placeholder for the thumbnail. The content is filled
+    // by calling ReadThumbnailFromFile.
+    Thumbnail(TabId tab_id, content::UIResourceProvider* ui_resource_provider);
+
+    Thumbnail(TabId tab_id,
+              SkBitmap bitmap,
+              float scale,
+              content::UIResourceProvider* ui_resource_provider);
+    Thumbnail(const Thumbnail& thumbnail);
+    void CleanupThumbnail();
+    bool AttemptToScheduleRebuildFromData();
+    void CleanupCPUData(bool force);
+    bool RebuildThumbnail();
+    bool CompressionRequired() const;
+    bool DataWriteRequired() const;
+    bool HasCompressedRawData() const;
+    bool IsValid() const;
+
+    // Returns the size of the content represented by this thumbnail.
+    gfx::Size GetContentSize() const;
+
+    TabId tab_id() const { return tab_id_; }
+    cc::UIResourceId ui_resource_id() const { return ui_resource_id_; }
+
+    // The ratio of the size of the thumbnail to the content size.
+    float scale() const { return scale_; }
+
+    // Returns the size of the data (pixels) held by this thumbnail. Can be the
+    // size of the uncompressed or compressed data.
+    gfx::Size data_size() const { return data_size_; }
+
+    virtual bool is_approximation() const { return false; }
+
+    // Called on the compression thread.
+    void Compress();
+    // Called on the disk thread. Returns true if writing was successful.
+    bool WriteThumbnailToFile(base::File& file);
+    // Called on the disk thread. Returns true if reading was successful.
+    bool ReadThumbnailFromFile(base::File& file);
+
+    // We invalidate the thumbnail content if a read/write/compress has failed.
+    void Invalidate();
+
+    SkBitmap raw_data() { return raw_data_; }
+
+   protected:
+    friend class base::RefCountedThreadSafe<Thumbnail>;
+    ~Thumbnail();
+
+   private:
+    void SetRawThumbnailData(SkBitmap bitmap);
+    void SetCompressedThumbnailData(skia::RefPtr<SkPixelRef> compressed_data,
+                                    gfx::Size scaled_content_size);
+    bool CleanupRequired();
+
+    TabId tab_id_;
+    SkBitmap raw_data_;
+    float scale_;
+    content::UIResourceProvider* ui_resource_provider_;
+    cc::UIResourceId ui_resource_id_;
+    skia::RefPtr<SkPixelRef> compressed_data_;
+    gfx::Size data_size_;
+    gfx::Size scaled_content_size_;
+    ThumbnailFormat format_;
+    bool rebuild_pending_;
+    bool data_write_pending_;
+    bool from_stream_;
+  };
+
+  class ApproxThumbnail : public Thumbnail {
+   public:
+    ApproxThumbnail(TabId tab_id,
+                    SkBitmap bitmap,
+                    float scale,
+                    content::UIResourceProvider* ui_resource_provider);
+
+    virtual bool is_approximation() const OVERRIDE { return true; }
+  };
+
+  class ThumbnailBitmap {
+   public:
+    ThumbnailBitmap();
+    ThumbnailBitmap(SkBitmap bitmap, float scale);
+    bool IsValid() const;
+    SkBitmap bitmap() const { return bitmap_; }
+    float scale() const { return scale_; }
+    ThumbnailBitmap CreateApproximation() const;
+
+   private:
+    SkBitmap bitmap_;
+    float scale_;
+  };
+
+  class ThumbnailMetaData {
+   public:
+    ThumbnailMetaData();
+    ThumbnailMetaData(const base::Time& current_time, const GURL& url);
+    const GURL& url() const { return url_; }
+    base::Time capture_time() const { return capture_time_; }
+
+   private:
+    base::Time capture_time_;
+    GURL url_;
+  };
+
+  class TabReadbackRequest : public base::RefCounted<TabReadbackRequest> {
+   public:
+    TabReadbackRequest(
+        TabId tab_id,
+        content::ContentViewCore* content_view_core,
+        float thumbnail_scale,
+        base::Callback<void(int, const ThumbnailBitmap&)> end_callback);
+
+    bool drop_after_readback() const { return drop_after_readback_; }
+
+    void Run();
+    void OnFinishGetTabThumbnailBitmap(bool success, const SkBitmap& bitmap);
+    void SetDropAfterReadback(bool flag) { drop_after_readback_ = flag; }
+
+   private:
+    TabId tab_id_;
+    content::ContentViewCore* content_view_core_;
+    const float thumbnail_scale_;
+    base::Callback<void(int, const ThumbnailBitmap&)> end_callback_;
+    bool drop_after_readback_;
+
+    base::WeakPtrFactory<TabReadbackRequest> weak_factory_;
+  };
+
+  template <class Key, class Value>
+  class LRUExpiringCache {
+   private:
+    typedef linked_hash_map<Key, Value> LinkedHashMap;
+
+   public:
+    typedef typename LinkedHashMap::iterator iterator;
+    typedef typename LinkedHashMap::const_iterator const_iterator;
+
+    explicit LRUExpiringCache(size_t max_cache_size)
+        : max_cache_size_(max_cache_size) {}
+
+    void Put(const Key& key, const Value& value) {
+      map_[key] = value;
+      EvictIfFull();
+    }
+
+    Value Get(const Key& key) {
+      iterator iter = map_.find(key);
+      if (iter != map_.end())
+        return iter->second;
+      return Value();
+    }
+
+    bool Contains(const Key& key) const {
+      const_iterator iter = map_.find(key);
+      return iter != map_.end();
+    }
+
+    Value Remove(const Key& key) {
+      Value val = Get(key);
+      map_.erase(key);
+      return val;
+    }
+
+    iterator begin() { return map_.begin(); }
+    iterator end() { return map_.end(); }
+    size_t MaximumCacheSize() const { return max_cache_size_; }
+    size_t size() const { return map_.size(); }
+
+   private:
+    void EvictIfFull() {
+      while (map_.size() > max_cache_size_) {
+        iterator it = map_.begin();
+        map_.erase(it);
+      }
+    }
+
+    size_t max_cache_size_;
+    LinkedHashMap map_;
+  };
+
+  typedef LRUExpiringCache<TabId, scoped_refptr<Thumbnail> >
+      ExpiringThumbnailCache;
+  typedef std::set<ThumbnailChangeListener*> ThumbnailChangeListenerSet;
+  typedef base::hash_map<TabId, scoped_refptr<TabReadbackRequest> >
+      TabReadbackRequestMap;
+  typedef base::hash_map<TabId, ThumbnailMetaData> ThumbnailMetaDataMap;
+  typedef std::list<scoped_refptr<Thumbnail> > ThumbnailQueue;
+
+ public:
+  ThumbnailCache(const std::string& disk_cache_path_str,
+                 size_t default_cache_size,
+                 size_t approximation_cache_size,
+                 size_t compression_queue_max_size,
+                 size_t write_queue_max_size,
+                 bool use_approximation_thumbnails,
+                 float thumbnail_scale);
+
+  ~ThumbnailCache();
+
+  void AddThumbnailChangeListener(ThumbnailChangeListener* listener);
+  void RemoveThumbnailChangeListener(ThumbnailChangeListener* listener);
+  void CacheTabThumbnail(const TabThumbnailProvider* tab);
+  void CacheTabThumbnailWithBitmap(const TabThumbnailProvider* tab,
+                                   const SkBitmap& bitmap,
+                                   float thumbnail_scale);
+  void HandleLowMemory(bool consider_gpu_memory);
+  void InvalidateIfChanged(const TabThumbnailProvider* tab);
+  void RemoveThumbnailsAndScheduleReload();
+  void CacheInTab(TabId tab_id);
+  void Remove(TabId tab_id);
+  void RemoveFromDiskAtAndAboveId(TabId min_id);
+  void RemoveFromDisk(TabId tab_id);
+  void UpdateVisibleIds(const TabIdList& last_visible_ids);
+  void ThumbnailRequested(TabId tab_id);
+  void SetUIResourceProvider(content::UIResourceProvider* ui_resource_provider);
+
+  // Implements content::UIResourceListener.
+  virtual void OnUIResourcesAreInvalid() OVERRIDE;
+  virtual void OnRecreateUIResources() OVERRIDE;
+
+ private:
+  // The task to run
+  static void CompressionTask(scoped_refptr<Thumbnail> thumbnail);
+
+  void PostCompressionTask(scoped_refptr<Thumbnail> thumbnail);
+
+  static void WriteTask(const base::FilePath& file_path,
+                        scoped_refptr<Thumbnail> thumbnail);
+
+  void PostWriteTask(scoped_refptr<Thumbnail> thumbnail);
+
+  static void ReadTask(const base::FilePath& file_path,
+                       scoped_refptr<Thumbnail> thumbnail);
+
+  void PostReadTask(scoped_refptr<Thumbnail> thumbnail);
+
+  static void RemoveFromDiskTask(const base::FilePath& file_path);
+  static void RemoveFromDiskAtAndAboveIdTask(const base::FilePath& dir_path,
+                                             TabId min_id);
+  scoped_refptr<Thumbnail> GetThumbnail(TabId tab_id);
+  scoped_refptr<Thumbnail> GetThumbnail(TabId tab_id, bool cache_in_if_missing);
+  void EndCacheTabThumbnail(TabId tab_id, const ThumbnailBitmap& bitmap);
+  bool CanReadTabContent(const TabThumbnailProvider* tab);
+  void PutThumbnail(TabId tab_id, const ThumbnailBitmap& thumbnail_bitmap);
+  void PutThumbnail(TabId tab_id,
+                    const ThumbnailBitmap& thumbnail_bitmap,
+                    scoped_refptr<Thumbnail> thumbnail);
+  bool CheckAndUpdateThumbnailMetaData(const TabThumbnailProvider* tab,
+                                       bool is_native_page);
+  void RemoveFromCache(ExpiringThumbnailCache& cache,
+                       const std::list<TabId>& tab_ids);
+  size_t HandleLowMemoryOnQueue(ThumbnailQueue& queue,
+                                bool consider_gpu_memory);
+  void RemoveFromQueues(TabId tab_id);
+  bool WriteThumbnailIfNecessary(scoped_refptr<Thumbnail> thumbnail);
+  bool CompressThumbnailIfNecessary(scoped_refptr<Thumbnail> thumbnail);
+  void WriteNextThumbnail();
+  bool RemoveDuplicateIdsFromQueueHelper(ThumbnailQueue& queue,
+                                         scoped_refptr<Thumbnail> thumbnail);
+  void ReadNextThumbnail(TabId id);
+  void ReadNextThumbnail();
+  void CompressNextThumbnail();
+  void RebuildThumbnail(scoped_refptr<Thumbnail> thumbnail,
+                        bool force_cleanup_cpu_data);
+  bool ShouldCleanupThumbnail(scoped_refptr<Thumbnail> thumbnail,
+                              const ExpiringThumbnailCache* forced_source);
+  void CleanupThumbnail(scoped_refptr<Thumbnail> thumbnail);
+  void CleanupThumbnail(scoped_refptr<Thumbnail> thumbnail,
+                        const ExpiringThumbnailCache* forced_source);
+  void NotifyListenersOfThumbnailChange(TabId tab_id, bool upgrade);
+  void NotifyListenersOfUIResourceUpdate(TabId tab_id);
+  base::FilePath GetFilePath(TabId tab_id) const;
+  bool ThumbnailInputFileExists(TabId tab_id) const;
+  void RemoveCorruptThumbnailSource(TabId tab_id);
+  void MakeSpaceForNewItemIfNecessary(TabId tab_id);
+  void RemoveThumbnailFromCache();
+  void AddIdToVisibleIds(TabId tab_id);
+  void CleanupPersistentData();
+
+  base::Time CurrentTime();
+
+  content::UIResourceProvider* ui_resource_provider_;
+  const base::FilePath disk_cache_path_;
+  const size_t compression_queue_max_size_;
+  const size_t write_queue_max_size_;
+
+  ExpiringThumbnailCache cache_;
+  ExpiringThumbnailCache approximation_cache_;
+  const bool use_approximation_thumbnails_;
+
+  // All thumbnails are scaled by this value.  This accounts for device's DPI
+  // (dots per inch).
+  const float thumbnail_scale_;
+
+  ThumbnailChangeListenerSet thumbnail_change_listeners_;
+
+  TabReadbackRequestMap pending_thumbnail_readbacks_;
+  ThumbnailMetaDataMap thumbnail_meta_data_;
+
+  ThumbnailQueue compression_queue_;
+  ThumbnailQueue write_queue_;
+  TabIdList read_queue_;
+
+  TabIdList last_visible_ids_;
+  TabIdList visible_ids_;
+
+  base::Thread compression_thread_;
+
+  base::WeakPtrFactory<ThumbnailCache> weak_factory_;
+};
+
+#endif  // CHROME_BROWSER_ANDROID_THUMBNAIL_CACHE_H_