Change ThumbnailStore to use sqlite instead of individual files.

chrome/browser/thumbnail_store.h

 // Copyright (c) 2009 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_THUMBNAIL_STORE_H_
 #define CHROME_BROWSER_THUMBNAIL_STORE_H_
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/file_path.h"
 #include "base/message_loop.h"
 #include "base/ref_counted.h"
 #include "base/timer.h"
 #include "chrome/browser/cancelable_request.h"
 #include "chrome/browser/history/history.h"
+#include "chrome/browser/history/url_database.h"  // For DBCloseScoper
 #include "chrome/common/pref_names.h"
 #include "chrome/common/ref_counted_util.h"
+#include "chrome/common/sqlite_compiled_statement.h"
+#include "chrome/common/thumbnail_score.h"
 #include "testing/gtest/include/gtest/gtest_prod.h"
 
 class DictionaryValue;
 class GURL;
 class HistoryService;
-class Pickle;
 class Profile;
 class SkBitmap;
-struct ThumbnailScore;
+struct sqlite3;
 namespace base {
 class Time;
 }
 
 // This storage interface provides storage for the thumbnails used
 // by the new_tab_ui.
 class ThumbnailStore : public base::RefCountedThreadSafe<ThumbnailStore> {
  public:
   ThumbnailStore();
   ~ThumbnailStore();
 
   // Must be called after creation but before other methods are called.
-  // file_path is a directory where a new database should be created
-  // or the location of an existing databse.
-  void Init(const FilePath& file_path, Profile* profile);
+  void Init(const FilePath& db_name,      // The location of the database.
+            Profile* profile);            // To get to the HistoryService.
 
   // Stores the given thumbnail and score with the associated url in the cache.
-  // If write_to_disk is true, the thumbnail data is written to disk on the
-  // file_thread.
   bool SetPageThumbnail(const GURL& url,
                         const SkBitmap& thumbnail,
-                        const ThumbnailScore& score,
-                        bool write_to_disk);
+                        const ThumbnailScore& score);
 
   // Sets *data to point to the thumbnail for the given url.
   // Returns false if no thumbnail available.
   bool GetPageThumbnail(const GURL& url, RefCountedBytes** data);
 
  private:
   FRIEND_TEST(ThumbnailStoreTest, RetrieveFromCache);
   FRIEND_TEST(ThumbnailStoreTest, RetrieveFromDisk);
   FRIEND_TEST(ThumbnailStoreTest, UpdateThumbnail);
   FRIEND_TEST(ThumbnailStoreTest, FollowRedirects);
   friend class ThumbnailStoreTest;
 
+  struct CacheEntry {
+    scoped_refptr<RefCountedBytes> data_;
+    ThumbnailScore score_;
+    bool dirty_;
+
+    CacheEntry() : data_(NULL), score_(ThumbnailScore()), dirty_(false) {}
+    CacheEntry(RefCountedBytes* data,
+               const ThumbnailScore& score,
+               bool dirty)
+        : data_(data),
+          score_(score),
+          dirty_(dirty) {}
+  };
+
   // Data structure used to store thumbnail data in memory.
-  typedef std::map<GURL, std::pair<scoped_refptr<RefCountedBytes>,
-      ThumbnailScore> > Cache;
+  typedef std::map<GURL, CacheEntry> Cache;
 
   // Most visited URLs and their redirect lists -------------------------------
 
   // Query the HistoryService for the most visited URLs and the most recent
   // redirect lists for those URLs.  This happens in the background and the
   // callback is OnURLDataAvailable.
   void UpdateURLData();
 
-  // The callback for UpdateURLData. The ThumbnailStore takes ownership of
-  // the most visited urls list and redirect lists passed in.
+  // The callback for UpdateURLData.
   void OnURLDataAvailable(std::vector<GURL>* urls,
                           history::RedirectMap* redirects);
 
   // Remove stale data --------------------------------------------------------
 
   // Remove entries from the in memory thumbnail cache and redirect lists
   // cache that have been blacklisted or are not in the top kMaxCacheSize
   // visited sites.
   void CleanCacheData();
 
-  // Deletes thumbnail data from disk for the given list of urls.
-  void DeleteThumbnails(
-      scoped_refptr<RefCountedVector<GURL> > thumbnail_urls) const;
+  // Disk operations ----------------------------------------------------------
 
-  // Disk operations ----------------------------------------------------------
+  // Initialize |db_| to the database specified in |db_name|.  If |cb_loop|
+  // is non-null, calls GetAllThumbnailsFromDisk.  Done on the file_thread.
+  void InitializeFromDB(const FilePath& db_name, MessageLoop* cb_loop);
 
   // Read all thumbnail data from the specified FilePath into a Cache object.
   // Done on the file_thread and returns to OnDiskDataAvailable on the thread
   // owning the specified MessageLoop.
-  void GetAllThumbnailsFromDisk(FilePath filepath, MessageLoop* cb_loop);
-
-  // Read the thumbnail data from the given file and stores it in the
-  // out parameters GURL, SkBitmap, and ThumbnailScore.
-  bool GetPageThumbnailFromDisk(const FilePath& file,
-                                GURL* url,
-                                RefCountedBytes* data,
-                                ThumbnailScore* score) const;
+  void GetAllThumbnailsFromDisk(MessageLoop* cb_loop);
 
   // Once thumbnail data from the disk is available from the file_thread,
   // this function is invoked on the main thread.  It takes ownership of the
   // Cache* passed in and retains this Cache* for the lifetime of the object.
   void OnDiskDataAvailable(Cache* cache);
 
-  // Write thumbnail data to disk for a given url.
-  bool WriteThumbnailToDisk(const GURL& url,
-                            scoped_refptr<RefCountedBytes> data,
-                            const ThumbnailScore& score) const;
-
-
-  // Pack the given ThumbnailScore into the given Pickle.
-  void PackScore(const ThumbnailScore& score, Pickle* packed) const;
-
-  // Unpack a ThumbnailScore from a given Pickle and associated iterator.
-  // Returns false is a ThumbnailScore could not be unpacked.
-  bool UnpackScore(ThumbnailScore* score,
-                   const Pickle& packed,
-                   void*& iter) const;
+  // Delete each URL in the given vector from the DB and write all dirty
+  // cache entries to the DB.
+  void CommitCacheToDB(
+      scoped_refptr<RefCountedVector<GURL> > stale_urls) const;
 
   // Decide whether to store data ---------------------------------------------
 
   bool ShouldStoreThumbnailForURL(const GURL& url) const;
 
   bool IsURLBlacklisted(const GURL& url) const;
 
   std::wstring GetDictionaryKeyForURL(const std::string& url) const;
 
   // Returns true if url is in most_visited_urls_.
   bool IsPopular(const GURL& url) const;
 
 
 
   // Member variables ---------------------------------------------------------
 
   // The Cache maintained by the object.
   scoped_ptr<Cache> cache_;
-  bool cache_initialized_;
 
-  // The location of the thumbnail store.
-  FilePath file_path_;
+  // The database holding the thumbnails on disk.
+  sqlite3* db_;
+  SqliteStatementCache* statement_cache_;
+  history::DBCloseScoper close_scoper_;
 
   // We hold a reference to the history service to query for most visited URLs
   // and redirect information.
   scoped_refptr<HistoryService> hs_;
 
   // A list of the most_visited_urls_ refreshed every 30mins from the
   // HistoryService.
   scoped_ptr<std::vector<GURL> > most_visited_urls_;
 
   // A pointer to the persistent URL blacklist for this profile.
   const DictionaryValue* url_blacklist_;
 
   // A map pairing the URL that a user typed to a list of URLs it was
   // redirected to. Ex:
   // google.com => { http://www.google.com/ }
   scoped_ptr<history::RedirectMap> redirect_urls_;
 
   // Timer on which UpdateURLData runs.
   base::RepeatingTimer<ThumbnailStore> timer_;
 
   // Consumer for queries to the HistoryService.
   CancelableRequestConsumer consumer_;
 
   static const unsigned int kMaxCacheSize = 45;
 
   DISALLOW_COPY_AND_ASSIGN(ThumbnailStore);
 };
 
 #endif  // CHROME_BROWSER_THUMBNAIL_STORE_H_