chromium/chrome/browser/extensions/activity_log/activity_database.h

// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CHROME_BROWSER_EXTENSIONS_ACTIVITY_LOG_ACTIVITY_DATABASE_H_
#define CHROME_BROWSER_EXTENSIONS_ACTIVITY_LOG_ACTIVITY_DATABASE_H_

#include "base/files/file_path.h"
#include "base/gtest_prod_util.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/ref_counted_memory.h"
#include "base/sequence_checker.h"
#include "base/strings/cstring_view.h"
#include "base/synchronization/lock.h"
#include "base/time/time.h"
#include "base/timer/timer.h"
#include "chrome/browser/extensions/activity_log/activity_actions.h"
#include "extensions/common/extension.h"
#include "sql/database.h"

namespace base {
class FilePath;
}

namespace extensions {

// Encapsulates the SQL connection for the activity log database.  This class
// holds the database connection and has methods for writing.  All of the
// methods except the constructor need to be called on the DB thread.
//
// Object ownership and lifetime is a bit complicated for ActivityLog,
// ActivityLogPolicy, and ActivityDatabase:
//
//    ActivityLog ----> ActivityLogPolicy ----> ActivityDatabase
//                         ^                               |
//                         |                               |
//                         \--(ActivityDatabase::Delegate)-/
//
// The ActivityLogPolicy object contains a pointer to the ActivityDatabase, and
// the ActivityDatabase contains a pointer back to the ActivityLogPolicy object
// (as an instance of ActivityDatabase::Delegate).
//
// Since some cleanup must happen on the database thread, deletion should occur
// as follows:
//   1. ActivityLog calls ActivityLogPolicy::Close()
//   2. ActivityLogPolicy should call ActivityDatabase::Close() on the database
//      thread.
//   3. ActivityDatabase::Close() shuts down the database, then calls
//      ActivityDatabase::Delegate::OnDatabaseClose().
//   4. ActivityDatabase::Delegate::OnDatabaseClose() should delete the
//      ActivityLogPolicy object.
//   5. ActivityDatabase::Close() finishes running by deleting the
//      ActivityDatabase object.
//
// (This assumes the common case that the ActivityLogPolicy uses an
// ActivityDatabase and implements the ActivityDatabase::Delegate interface.
// It is also possible for an ActivityLogPolicy to not use a database at all,
// in which case ActivityLogPolicy::Close() should directly delete itself.)
class ActivityDatabase { … };

}  // namespace extensions

#endif  // CHROME_BROWSER_EXTENSIONS_ACTIVITY_LOG_ACTIVITY_DATABASE_H_