12a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)// Copyright 2013 The Chromium Authors. All rights reserved. 22a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)// Use of this source code is governed by a BSD-style license that can be 32a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)// found in the LICENSE file. 42a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) 52a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)#ifndef CHROME_BROWSER_HISTORY_HISTORY_DB_TASK_H_ 62a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)#define CHROME_BROWSER_HISTORY_HISTORY_DB_TASK_H_ 72a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) 82a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)namespace history { 92a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) 102a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)class HistoryBackend; 112a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)class HistoryDatabase; 122a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) 132a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)// HistoryDBTask can be used to process arbitrary work on the history backend 142a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)// thread. HistoryDBTask is scheduled using HistoryService::ScheduleDBTask. 152a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)// When HistoryBackend processes the task it invokes RunOnDBThread. Once the 162a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)// task completes and has not been canceled, DoneRunOnMainThread is invoked back 175f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)// on the main thread, after which this object is destroyed, also on the 185f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)// main thread. 195f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles)class HistoryDBTask { 202a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) public: 215f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) virtual ~HistoryDBTask() {} 225f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) 232a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) // Invoked on the database thread. The return value indicates whether the 242a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) // task is done. A return value of true signals the task is done and 252a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) // RunOnDBThread should NOT be invoked again. A return value of false 262a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) // indicates the task is not done, and should be run again after other 272a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) // tasks are given a chance to be processed. 282a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) virtual bool RunOnDBThread(HistoryBackend* backend, HistoryDatabase* db) = 0; 292a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) 302a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) // Invoked on the main thread once RunOnDBThread has returned true. This is 312a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) // only invoked if the request was not canceled and returned true from 322a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) // RunOnDBThread. 332a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) virtual void DoneRunOnMainThread() = 0; 342a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)}; 352a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) 362a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)} // namespace history 372a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) 382a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)#endif // CHROME_BROWSER_HISTORY_HISTORY_DB_TASK_H_ 39