Only invoke WebKit methods in browsing data helpers on the WEBKIT thread.

chrome/browser/browsing_data_database_helper.h

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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_BROWSING_DATA_DATABASE_HELPER_H_
 #define CHROME_BROWSER_BROWSING_DATA_DATABASE_HELPER_H_
 #pragma once
 
 #include <string>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/scoped_ptr.h"
+#include "base/synchronization/lock.h"
 #include "chrome/common/url_constants.h"
 #include "googleurl/src/gurl.h"
 #include "webkit/database/database_tracker.h"
 
 class Profile;
 
-// This class fetches database information in the FILE thread, and notifies the
-// UI thread upon completion.
+// This class fetches database information in the WEBKIT thread, and notifies
+// the UI thread upon completion.
 // A client of this class need to call StartFetching from the UI thread to
 // initiate the flow, and it'll be notified by the callback in its UI
 // thread at some later point.
 // The client must call CancelNotification() if it's destroyed before the
 // callback is notified.
 class BrowsingDataDatabaseHelper
     : public base::RefCountedThreadSafe<BrowsingDataDatabaseHelper> {
  public:
   // Contains detailed information about a web database.
   struct DatabaseInfo {
@@ skipping 24 matching lines @@
   // callback.
   // This must be called only in the UI thread.
   virtual void StartFetching(
       Callback1<const std::vector<DatabaseInfo>& >::Type* callback);
 
   // Cancels the notification callback (i.e., the window that created it no
   // longer exists).
   // This must be called only in the UI thread.
   virtual void CancelNotification();
 
-  // Requests a single database to be deleted in the FILE thread. This must be
+  // Requests a single database to be deleted in the WEBKIT thread. This must be
   // called in the UI thread.
   virtual void DeleteDatabase(const std::string& origin,
                               const std::string& name);
 
  protected:
   friend class base::RefCountedThreadSafe<BrowsingDataDatabaseHelper>;
   virtual ~BrowsingDataDatabaseHelper();
 
-  // This only mutates in the FILE thread.
-  std::vector<DatabaseInfo> database_info_;
-
- private:
-  // Enumerates all databases. This must be called in the FILE thread.
-  void FetchDatabaseInfoInFileThread();
-
   // Notifies the completion callback. This must be called in the UI thread.
   void NotifyInUIThread();
 
-  // Delete a single database file. This must be called in the FILE thread.
-  void DeleteDatabaseInFileThread(const std::string& origin,
-                                  const std::string& name);
-
-  scoped_refptr<webkit_database::DatabaseTracker> tracker_;
+  // This only mutates in the WEBKIT thread.
+  std::vector<DatabaseInfo> database_info_;
 
   // This only mutates on the UI thread.
   scoped_ptr<Callback1<const std::vector<DatabaseInfo>& >::Type >
       completion_callback_;
 
   // Indicates whether or not we're currently fetching information:
   // it's true when StartFetching() is called in the UI thread, and it's reset
   // after we notify the callback in the UI thread.
   // This only mutates on the UI thread.
   bool is_fetching_;
 
+ private:
+  // Enumerates all databases. This must be called in the WEBKIT thread.
+  void FetchDatabaseInfoInWebKitThread();
+
+  // Delete a single database file. This must be called in the WEBKIT thread.
+  void DeleteDatabaseInWebKitThread(const std::string& origin,
+                                  const std::string& name);
+
+  scoped_refptr<webkit_database::DatabaseTracker> tracker_;
+
   DISALLOW_COPY_AND_ASSIGN(BrowsingDataDatabaseHelper);
 };
 
 // This class is a thin wrapper around BrowsingDataDatabaseHelper that does not
 // fetch its information from the database tracker, but gets them passed as
 // a parameter during construction.
 class CannedBrowsingDataDatabaseHelper : public BrowsingDataDatabaseHelper {
  public:
   explicit CannedBrowsingDataDatabaseHelper(Profile* profile);
 
   // Add a database to the set of canned databases that is returned by this
   // helper.
   void AddDatabase(const GURL& origin,
                    const std::string& name,
                    const std::string& description);
 
   // Clear the list of canned databases.
   void Reset();
 
   // True if no databases are currently stored.
   bool empty() const;
 
   // BrowsingDataDatabaseHelper methods.
   virtual void StartFetching(
       Callback1<const std::vector<DatabaseInfo>& >::Type* callback);
   virtual void CancelNotification() {}
 
  private:
+  struct PendingDatabaseInfo {
+    PendingDatabaseInfo();
+    PendingDatabaseInfo(const GURL& origin,
+                        const std::string& name,
+                        const std::string& description);
+    ~PendingDatabaseInfo();
+
+    GURL origin;
+    std::string name;
+    std::string description;
+  };
+
   virtual ~CannedBrowsingDataDatabaseHelper() {}
 
+  // Converts the pending database info structs to database info structs.
+  void ConvertInfoInWebKitThread();
+
+  // Used to protect access to pending_database_info_.
+  mutable base::Lock lock_;
+
+  // This may mutate on WEBKIT and UI threads.
+  std::vector<PendingDatabaseInfo> pending_database_info_;
+
   DISALLOW_COPY_AND_ASSIGN(CannedBrowsingDataDatabaseHelper);
 };
 
 #endif  // CHROME_BROWSER_BROWSING_DATA_DATABASE_HELPER_H_