Store the next notification id in the notification database.

content/browser/notifications/notification_database.h

 // Copyright 2015 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 CONTENT_BROWSER_NOTIFICATIONS_NOTIFICATION_DATABASE_H_
 #define CONTENT_BROWSER_NOTIFICATIONS_NOTIFICATION_DATABASE_H_
 
+#include <stdint.h>
+
 #include "base/callback.h"
 #include "base/files/file_path.h"
 #include "base/sequence_checker.h"
 #include "content/common/content_export.h"
 
 namespace leveldb {
 class DB;
 class Env;
+class WriteBatch;
 }
 
 namespace content {
 
 // Implementation of the persistent notification database.
 //
 // This class can be constructed on any thread, but method calls must only be
 // made on a thread or sequenced task runner that allows file I/O. The same
 // thread or task runner must be used for all method calls.
 class CONTENT_EXPORT NotificationDatabase {
@@ skipping 16 matching lines @@
 
   explicit NotificationDatabase(const base::FilePath& path);
   ~NotificationDatabase();
 
   // Opens the database. If |path| is non-empty, it will be created on the given
   // directory on the filesystem. If |path| is empty, the database will be
   // created in memory instead, and its lifetime will be tied to this instance.
   // |create_if_missing| determines whether to create the database if necessary.
   Status Open(bool create_if_missing);
 
+  // Returns whether the next available notification id could be read, and
+  // stores the id in |notification_id| if the read was successful.
+  Status GetNextNotificationId(int64_t* notification_id);
+
   // Completely destroys the contents of this database.
   Status Destroy();
 
  private:
   friend class NotificationDatabaseTest;
 
   // TODO(peter): Convert to an enum class when DCHECK_EQ supports this.
   // See https://crbug.com/463869.
   enum State {
     STATE_UNINITIALIZED,
     STATE_INITIALIZED,
     STATE_DISABLED,
   };
 
+  // Increments the available notification id to |current_notification_id| + 1.
+  // |current_notification_id| must be equal to or higher than the last id
+  // returned by GetNextNotificationId(). The value will be written to |batch|.
+  void IncrementNextNotificationId(leveldb::WriteBatch* batch,
+                                   int64_t current_notification_id);
+
   // Returns whether the database has been opened.
   bool IsOpen() const { return db_ != nullptr; }
 
   // Returns whether the database should only exist in memory.
   bool IsInMemoryDatabase() const { return path_.empty(); }
 
+  // Exposes the LevelDB database used to back this notification database.
+  // Should only be used for testing purposes.
+  leveldb::DB* db() { return db_.get(); }

[Bernhard Bauer, 2015/03/11 22:02:38]

Name this GetDBForTesting(), so the presubmit check can catch usage of this in
production code?

[Peter Beverloo, 2015/03/11 22:33:33]

Done.

+
   base::FilePath path_;
 
   // These members depend on the declaration order for destruction.
   scoped_ptr<leveldb::Env> env_;
   scoped_ptr<leveldb::DB> db_;
 
+  int64_t next_available_notification_id_;
+
   State state_;
 
   base::SequenceChecker sequence_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(NotificationDatabase);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_NOTIFICATIONS_NOTIFICATION_DATABASE_H_