13f50c38dc070f4bb515c1b64450dae14f316474eKristian Monsen// Copyright (c) 2011 The Chromium Authors. All rights reserved. 2c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// Use of this source code is governed by a BSD-style license that can be 3c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// found in the LICENSE file. 4c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 5c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott#ifndef BASE_MESSAGE_PUMP_WIN_H_ 6c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott#define BASE_MESSAGE_PUMP_WIN_H_ 73345a6884c488ff3a535c2c9acdd33d74b37e311Iain Merrick#pragma once 8c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 9c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott#include <windows.h> 10c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 11c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott#include <list> 12c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 13ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen#include "base/base_api.h" 14c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch#include "base/basictypes.h" 15c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott#include "base/message_pump.h" 16c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott#include "base/observer_list.h" 17c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott#include "base/time.h" 183f50c38dc070f4bb515c1b64450dae14f316474eKristian Monsen#include "base/win/scoped_handle.h" 19c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 20c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scottnamespace base { 21c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 22c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// MessagePumpWin serves as the base for specialized versions of the MessagePump 23c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// for Windows. It provides basic functionality like handling of observers and 24c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// controlling the lifetime of the message pump. 25ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsenclass BASE_API MessagePumpWin : public MessagePump { 26c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott public: 27c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // An Observer is an object that receives global notifications from the 28c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch // UI MessageLoop. 29c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // 30c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // NOTE: An Observer implementation should be extremely fast! 31c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // 32c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott class Observer { 33c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott public: 34c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott virtual ~Observer() {} 35c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 36c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // This method is called before processing a message. 37c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // The message may be undefined in which case msg.message is 0 38c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott virtual void WillProcessMessage(const MSG& msg) = 0; 39c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 40c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // This method is called when control returns from processing a UI message. 41c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // The message may be undefined in which case msg.message is 0 42c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott virtual void DidProcessMessage(const MSG& msg) = 0; 43c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott }; 44c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 45c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Dispatcher is used during a nested invocation of Run to dispatch events. 46c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // If Run is invoked with a non-NULL Dispatcher, MessageLoop does not 47c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // dispatch events (or invoke TranslateMessage), rather every message is 48c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // passed to Dispatcher's Dispatch method for dispatch. It is up to the 49c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Dispatcher to dispatch, or not, the event. 50c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // 51c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // The nested loop is exited by either posting a quit, or returning false 52c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // from Dispatch. 53c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott class Dispatcher { 54c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott public: 55c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott virtual ~Dispatcher() {} 56c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Dispatches the event. If true is returned processing continues as 57c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // normal. If false is returned, the nested loop exits immediately. 58c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott virtual bool Dispatch(const MSG& msg) = 0; 59c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott }; 60c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 61c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott MessagePumpWin() : have_work_(0), state_(NULL) {} 62c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott virtual ~MessagePumpWin() {} 63c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 64c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Add an Observer, which will start receiving notifications immediately. 65c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott void AddObserver(Observer* observer); 66c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 67c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Remove an Observer. It is safe to call this method while an Observer is 68c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // receiving a notification callback. 69c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott void RemoveObserver(Observer* observer); 70c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 71c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Give a chance to code processing additional messages to notify the 72c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // message loop observers that another message has been processed. 73c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott void WillProcessMessage(const MSG& msg); 74c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott void DidProcessMessage(const MSG& msg); 75c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 76c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Like MessagePump::Run, but MSG objects are routed through dispatcher. 77c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott void RunWithDispatcher(Delegate* delegate, Dispatcher* dispatcher); 78c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 79c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // MessagePump methods: 80c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott virtual void Run(Delegate* delegate) { RunWithDispatcher(delegate, NULL); } 81c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott virtual void Quit(); 82c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 83c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott protected: 84c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott struct RunState { 85c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott Delegate* delegate; 86c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott Dispatcher* dispatcher; 87c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 88c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Used to flag that the current Run() invocation should return ASAP. 89c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott bool should_quit; 90c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 91c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Used to count how many Run() invocations are on the stack. 92c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott int run_depth; 93c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott }; 94c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 95c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott virtual void DoRunLoop() = 0; 96c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott int GetCurrentDelay() const; 97c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 98c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott ObserverList<Observer> observers_; 99c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 100c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // The time at which delayed work should run. 101513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch TimeTicks delayed_work_time_; 102c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 103c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // A boolean value used to indicate if there is a kMsgDoWork message pending 104c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // in the Windows Message queue. There is at most one such message, and it 105c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // can drive execution of tasks when a native message pump is running. 106c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott LONG have_work_; 107c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 108c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // State for the current invocation of Run. 109c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott RunState* state_; 110c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott}; 111c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 112c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott//----------------------------------------------------------------------------- 113c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// MessagePumpForUI extends MessagePumpWin with methods that are particular to a 114c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// MessageLoop instantiated with TYPE_UI. 115c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// 116c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// MessagePumpForUI implements a "traditional" Windows message pump. It contains 117c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// a nearly infinite loop that peeks out messages, and then dispatches them. 118c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// Intermixed with those peeks are callouts to DoWork for pending tasks, and 119c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// DoDelayedWork for pending timers. When there are no events to be serviced, 120c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// this pump goes into a wait state. In most cases, this message pump handles 121c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// all processing. 122c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// 123c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// However, when a task, or windows event, invokes on the stack a native dialog 124c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// box or such, that window typically provides a bare bones (native?) message 125c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// pump. That bare-bones message pump generally supports little more than a 126c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// peek of the Windows message queue, followed by a dispatch of the peeked 127c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// message. MessageLoop extends that bare-bones message pump to also service 128c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// Tasks, at the cost of some complexity. 129c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// 130c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// The basic structure of the extension (refered to as a sub-pump) is that a 131c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// special message, kMsgHaveWork, is repeatedly injected into the Windows 132c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// Message queue. Each time the kMsgHaveWork message is peeked, checks are 133c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// made for an extended set of events, including the availability of Tasks to 134c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// run. 135c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// 136c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// After running a task, the special message kMsgHaveWork is again posted to 137c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// the Windows Message queue, ensuring a future time slice for processing a 138c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// future event. To prevent flooding the Windows Message queue, care is taken 139c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// to be sure that at most one kMsgHaveWork message is EVER pending in the 140c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// Window's Message queue. 141c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// 142c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// There are a few additional complexities in this system where, when there are 143c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// no Tasks to run, this otherwise infinite stream of messages which drives the 144c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// sub-pump is halted. The pump is automatically re-started when Tasks are 145c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// queued. 146c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// 147c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// A second complexity is that the presence of this stream of posted tasks may 148c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// prevent a bare-bones message pump from ever peeking a WM_PAINT or WM_TIMER. 149c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// Such paint and timer events always give priority to a posted message, such as 150c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// kMsgHaveWork messages. As a result, care is taken to do some peeking in 151c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// between the posting of each kMsgHaveWork message (i.e., after kMsgHaveWork 152c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// is peeked, and before a replacement kMsgHaveWork is posted). 153c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// 154c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// NOTE: Although it may seem odd that messages are used to start and stop this 155c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// flow (as opposed to signaling objects, etc.), it should be understood that 156c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// the native message pump will *only* respond to messages. As a result, it is 157c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// an excellent choice. It is also helpful that the starter messages that are 158c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// placed in the queue when new task arrive also awakens DoRunLoop. 159c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// 160ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsenclass BASE_API MessagePumpForUI : public MessagePumpWin { 161c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott public: 162c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // The application-defined code passed to the hook procedure. 163c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott static const int kMessageFilterCode = 0x5001; 164c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 165c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott MessagePumpForUI(); 166c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott virtual ~MessagePumpForUI(); 167c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 168c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // MessagePump methods: 169c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott virtual void ScheduleWork(); 170513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch virtual void ScheduleDelayedWork(const TimeTicks& delayed_work_time); 171c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 172c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Applications can call this to encourage us to process all pending WM_PAINT 173c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // messages. This method will process all paint messages the Windows Message 174c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // queue can provide, up to some fixed number (to avoid any infinite loops). 175c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott void PumpOutPendingPaintMessages(); 176c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 177c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott private: 178c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott static LRESULT CALLBACK WndProcThunk( 179c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam); 180c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott virtual void DoRunLoop(); 181c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott void InitMessageWnd(); 182c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott void WaitForWork(); 183c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott void HandleWorkMessage(); 184c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott void HandleTimerMessage(); 185c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott bool ProcessNextWindowsMessage(); 186c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott bool ProcessMessageHelper(const MSG& msg); 187c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott bool ProcessPumpReplacementMessage(); 188c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 189c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // A hidden message-only window. 190c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott HWND message_hwnd_; 191c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott}; 192c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 193c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott//----------------------------------------------------------------------------- 194c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// MessagePumpForIO extends MessagePumpWin with methods that are particular to a 195c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// MessageLoop instantiated with TYPE_IO. This version of MessagePump does not 196c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// deal with Windows mesagges, and instead has a Run loop based on Completion 197c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// Ports so it is better suited for IO operations. 198c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott// 199ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsenclass BASE_API MessagePumpForIO : public MessagePumpWin { 200c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott public: 201c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott struct IOContext; 202c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 203c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Clients interested in receiving OS notifications when asynchronous IO 204c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // operations complete should implement this interface and register themselves 205c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // with the message pump. 206c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // 207c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Typical use #1: 208c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // // Use only when there are no user's buffers involved on the actual IO, 209c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // // so that all the cleanup can be done by the message pump. 210c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // class MyFile : public IOHandler { 211c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // MyFile() { 212c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // ... 213c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // context_ = new IOContext; 214c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // context_->handler = this; 215c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // message_pump->RegisterIOHandler(file_, this); 216c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // } 217c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // ~MyFile() { 218c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // if (pending_) { 219c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // // By setting the handler to NULL, we're asking for this context 220c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // // to be deleted when received, without calling back to us. 221c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // context_->handler = NULL; 222c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // } else { 223c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // delete context_; 224c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // } 225c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // } 226c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // virtual void OnIOCompleted(IOContext* context, DWORD bytes_transfered, 227c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // DWORD error) { 228c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // pending_ = false; 229c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // } 230c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // void DoSomeIo() { 231c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // ... 232c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // // The only buffer required for this operation is the overlapped 233c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // // structure. 234c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // ConnectNamedPipe(file_, &context_->overlapped); 235c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // pending_ = true; 236c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // } 237c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // bool pending_; 238c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // IOContext* context_; 239c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // HANDLE file_; 240c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // }; 241c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // 242c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Typical use #2: 243c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // class MyFile : public IOHandler { 244c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // MyFile() { 245c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // ... 246c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // message_pump->RegisterIOHandler(file_, this); 247c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // } 248c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // // Plus some code to make sure that this destructor is not called 249c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // // while there are pending IO operations. 250c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // ~MyFile() { 251c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // } 252c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // virtual void OnIOCompleted(IOContext* context, DWORD bytes_transfered, 253c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // DWORD error) { 254c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // ... 255c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // delete context; 256c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // } 257c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // void DoSomeIo() { 258c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // ... 259c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // IOContext* context = new IOContext; 260c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // // This is not used for anything. It just prevents the context from 261c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // // being considered "abandoned". 262c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // context->handler = this; 263c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // ReadFile(file_, buffer, num_bytes, &read, &context->overlapped); 264c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // } 265c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // HANDLE file_; 266c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // }; 267c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // 268c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Typical use #3: 269c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Same as the previous example, except that in order to deal with the 270c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // requirement stated for the destructor, the class calls WaitForIOCompletion 271c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // from the destructor to block until all IO finishes. 272c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // ~MyFile() { 273c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // while(pending_) 274c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // message_pump->WaitForIOCompletion(INFINITE, this); 275c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // } 276c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // 277c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott class IOHandler { 278c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott public: 279c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott virtual ~IOHandler() {} 280c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // This will be called once the pending IO operation associated with 281c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // |context| completes. |error| is the Win32 error code of the IO operation 282c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // (ERROR_SUCCESS if there was no error). |bytes_transfered| will be zero 283c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // on error. 284c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott virtual void OnIOCompleted(IOContext* context, DWORD bytes_transfered, 285c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott DWORD error) = 0; 286c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott }; 287c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 288c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch // An IOObserver is an object that receives IO notifications from the 289c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch // MessagePump. 290c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch // 291c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch // NOTE: An IOObserver implementation should be extremely fast! 292c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch class IOObserver { 293c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch public: 294c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch IOObserver() {} 295c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch 296c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch virtual void WillProcessIOEvent() = 0; 297c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch virtual void DidProcessIOEvent() = 0; 298c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch 299c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch protected: 300c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch virtual ~IOObserver() {} 301c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch }; 302c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch 303c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // The extended context that should be used as the base structure on every 304c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // overlapped IO operation. |handler| must be set to the registered IOHandler 305c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // for the given file when the operation is started, and it can be set to NULL 306c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // before the operation completes to indicate that the handler should not be 307c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // called anymore, and instead, the IOContext should be deleted when the OS 308c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // notifies the completion of this operation. Please remember that any buffers 309c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // involved with an IO operation should be around until the callback is 310c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // received, so this technique can only be used for IO that do not involve 311c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // additional buffers (other than the overlapped structure itself). 312c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott struct IOContext { 313c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott OVERLAPPED overlapped; 314c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott IOHandler* handler; 315c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott }; 316c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 317c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott MessagePumpForIO(); 318c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott virtual ~MessagePumpForIO() {} 319c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 320c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // MessagePump methods: 321c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott virtual void ScheduleWork(); 322513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch virtual void ScheduleDelayedWork(const TimeTicks& delayed_work_time); 323c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 324c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Register the handler to be used when asynchronous IO for the given file 325c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // completes. The registration persists as long as |file_handle| is valid, so 326c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // |handler| must be valid as long as there is pending IO for the given file. 327c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott void RegisterIOHandler(HANDLE file_handle, IOHandler* handler); 328c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 329c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // Waits for the next IO completion that should be processed by |filter|, for 330c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // up to |timeout| milliseconds. Return true if any IO operation completed, 331c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // regardless of the involved handler, and false if the timeout expired. If 332c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // the completion port received any message and the involved IO handler 333c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // matches |filter|, the callback is called before returning from this code; 334c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // if the handler is not the one that we are looking for, the callback will 335c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // be postponed for another time, so reentrancy problems can be avoided. 336c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // External use of this method should be reserved for the rare case when the 337c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // caller is willing to allow pausing regular task dispatching on this thread. 338c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott bool WaitForIOCompletion(DWORD timeout, IOHandler* filter); 339c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 340c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch void AddIOObserver(IOObserver* obs); 341c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch void RemoveIOObserver(IOObserver* obs); 342c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch 343c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott private: 344c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott struct IOItem { 345c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott IOHandler* handler; 346c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott IOContext* context; 347c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott DWORD bytes_transfered; 348c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott DWORD error; 349c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott }; 350c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 351c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott virtual void DoRunLoop(); 352c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott void WaitForWork(); 353c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott bool MatchCompletedIOItem(IOHandler* filter, IOItem* item); 354c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott bool GetIOItem(DWORD timeout, IOItem* item); 355c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott bool ProcessInternalIOItem(const IOItem& item); 356c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch void WillProcessIOEvent(); 357c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch void DidProcessIOEvent(); 358c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 359c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // The completion port associated with this thread. 3603f50c38dc070f4bb515c1b64450dae14f316474eKristian Monsen win::ScopedHandle port_; 361c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // This list will be empty almost always. It stores IO completions that have 362c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott // not been delivered yet because somebody was doing cleanup. 363c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott std::list<IOItem> completed_io_; 364c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch 365c407dc5cd9bdc5668497f21b26b09d988ab439deBen Murdoch ObserverList<IOObserver> io_observers_; 366c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott}; 367c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 368c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott} // namespace base 369c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott 370c7f5f8508d98d5952d42ed7648c2a8f30a4da156Patrick Scott#endif // BASE_MESSAGE_PUMP_WIN_H_ 371