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// 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 {
public:
// Result status codes for interations with the database. Will be used for
// UMA, so the assigned ids must remain stable.
enum Status {
STATUS_OK = 0,
// The database, or the key associated with the operation, could not be
// found.
STATUS_ERROR_NOT_FOUND = 1,
// The database, or data in the database, could not be parsed as valid data.
STATUS_ERROR_CORRUPTED = 2,
// General failure code. More specific failures should be used if available.
STATUS_ERROR_FAILED = 3,
};
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) const;
// 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,
};
// Writes the next available notification id as a put operation to |batch|.
void WriteNextNotificationId(leveldb::WriteBatch* batch,
int64_t next_notification_id) const;
// 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* GetDBForTesting() const { return db_.get(); }
base::FilePath path_;
// The declaration order for these members matters, as |db_| depends on |env_|
// and thus has to be destructed first.
scoped_ptr<leveldb::Env> env_;
scoped_ptr<leveldb::DB> db_;
State state_;
base::SequenceChecker sequence_checker_;
DISALLOW_COPY_AND_ASSIGN(NotificationDatabase);
};
} // namespace content
#endif // CONTENT_BROWSER_NOTIFICATIONS_NOTIFICATION_DATABASE_H_
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