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// Copyright (c) 2011 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.
#include <stddef.h>
#include <windows.h>
#include <mmsystem.h>
#include "base/event_recorder.h"
#include "base/files/file_util.h"
#include "base/logging.h"
// A note about time.
// For perfect playback of events, you'd like a very accurate timer
// so that events are played back at exactly the same time that
// they were recorded. However, windows has a clock which is only
// granular to ~15ms. We see more consistent event playback when
// using a higher resolution timer. To do this, we use the
// timeGetTime API instead of the default GetTickCount() API.
namespace base {
EventRecorder* EventRecorder::current_ = NULL;
LRESULT CALLBACK StaticRecordWndProc(int nCode, WPARAM wParam,
LPARAM lParam) {
DCHECK(EventRecorder::current());
return EventRecorder::current()->RecordWndProc(nCode, wParam, lParam);
}
LRESULT CALLBACK StaticPlaybackWndProc(int nCode, WPARAM wParam,
LPARAM lParam) {
DCHECK(EventRecorder::current());
return EventRecorder::current()->PlaybackWndProc(nCode, wParam, lParam);
}
EventRecorder::~EventRecorder() {
// Try to assert early if the caller deletes the recorder
// while it is still in use.
DCHECK(!journal_hook_);
DCHECK(!is_recording_ && !is_playing_);
}
bool EventRecorder::StartRecording(const FilePath& filename) {
if (journal_hook_ != NULL)
return false;
if (is_recording_ || is_playing_)
return false;
// Open the recording file.
DCHECK(!file_);
file_ = OpenFile(filename, "wb+");
if (!file_) {
DLOG(ERROR) << "EventRecorder could not open log file";
return false;
}
// Set the faster clock, if possible.
::timeBeginPeriod(1);
// Set the recording hook. JOURNALRECORD can only be used as a global hook.
journal_hook_ = ::SetWindowsHookEx(WH_JOURNALRECORD, StaticRecordWndProc,
GetModuleHandle(NULL), 0);
if (!journal_hook_) {
DLOG(ERROR) << "EventRecorder Record Hook failed";
CloseFile(file_);
return false;
}
is_recording_ = true;
return true;
}
void EventRecorder::StopRecording() {
if (is_recording_) {
DCHECK(journal_hook_ != NULL);
if (!::UnhookWindowsHookEx(journal_hook_)) {
DLOG(ERROR) << "EventRecorder Unhook failed";
// Nothing else we can really do here.
return;
}
::timeEndPeriod(1);
DCHECK(file_ != NULL);
CloseFile(file_);
file_ = NULL;
journal_hook_ = NULL;
is_recording_ = false;
}
}
bool EventRecorder::StartPlayback(const FilePath& filename) {
if (journal_hook_ != NULL)
return false;
if (is_recording_ || is_playing_)
return false;
// Open the recording file.
DCHECK(!file_);
file_ = OpenFile(filename, "rb");
if (!file_) {
DLOG(ERROR) << "EventRecorder Playback could not open log file";
return false;
}
// Read the first event from the record.
if (fread(&playback_msg_, sizeof(EVENTMSG), 1, file_) != 1) {
DLOG(ERROR) << "EventRecorder Playback has no records!";
CloseFile(file_);
return false;
}
// Set the faster clock, if possible.
::timeBeginPeriod(1);
// Playback time is tricky. When playing back, we read a series of events,
// each with timeouts. Simply subtracting the delta between two timers will
// lead to fast playback (about 2x speed). The API has two events, one
// which advances to the next event (HC_SKIP), and another that requests the
// event (HC_GETNEXT). The same event will be requested multiple times.
// Each time the event is requested, we must calculate the new delay.
// To do this, we track the start time of the playback, and constantly
// re-compute the delay. I mention this only because I saw two examples
// of how to use this code on the net, and both were broken :-)
playback_start_time_ = timeGetTime();
playback_first_msg_time_ = playback_msg_.time;
// Set the hook. JOURNALPLAYBACK can only be used as a global hook.
journal_hook_ = ::SetWindowsHookEx(WH_JOURNALPLAYBACK, StaticPlaybackWndProc,
GetModuleHandle(NULL), 0);
if (!journal_hook_) {
DLOG(ERROR) << "EventRecorder Playback Hook failed";
return false;
}
is_playing_ = true;
return true;
}
void EventRecorder::StopPlayback() {
if (is_playing_) {
DCHECK(journal_hook_ != NULL);
if (!::UnhookWindowsHookEx(journal_hook_)) {
DLOG(ERROR) << "EventRecorder Unhook failed";
// Nothing else we can really do here.
}
DCHECK(file_ != NULL);
CloseFile(file_);
file_ = NULL;
::timeEndPeriod(1);
journal_hook_ = NULL;
is_playing_ = false;
}
}
// Windows callback hook for the recorder.
LRESULT EventRecorder::RecordWndProc(int nCode, WPARAM wParam, LPARAM lParam) {
static bool recording_enabled = true;
EVENTMSG* msg_ptr = NULL;
// The API says we have to do this.
// See http://msdn2.microsoft.com/en-us/library/ms644983(VS.85).aspx
if (nCode < 0)
return ::CallNextHookEx(journal_hook_, nCode, wParam, lParam);
// Check for the break key being pressed and stop recording.
if (::GetKeyState(VK_CANCEL) & 0x8000) {
StopRecording();
return ::CallNextHookEx(journal_hook_, nCode, wParam, lParam);
}
// The Journal Recorder must stop recording events when system modal
// dialogs are present. (see msdn link above)
switch (nCode) {
case HC_SYSMODALON:
recording_enabled = false;
break;
case HC_SYSMODALOFF:
recording_enabled = true;
break;
}
if (nCode == HC_ACTION && recording_enabled) {
// Aha - we have an event to record.
msg_ptr = reinterpret_cast<EVENTMSG*>(lParam);
msg_ptr->time = timeGetTime();
fwrite(msg_ptr, sizeof(EVENTMSG), 1, file_);
fflush(file_);
}
return CallNextHookEx(journal_hook_, nCode, wParam, lParam);
}
// Windows callback for the playback mode.
LRESULT EventRecorder::PlaybackWndProc(int nCode, WPARAM wParam,
LPARAM lParam) {
static bool playback_enabled = true;
int delay = 0;
switch (nCode) {
// A system modal dialog box is being displayed. Stop playing back
// messages.
case HC_SYSMODALON:
playback_enabled = false;
break;
// A system modal dialog box is destroyed. We can start playing back
// messages again.
case HC_SYSMODALOFF:
playback_enabled = true;
break;
// Prepare to copy the next mouse or keyboard event to playback.
case HC_SKIP:
if (!playback_enabled)
break;
// Read the next event from the record.
if (fread(&playback_msg_, sizeof(EVENTMSG), 1, file_) != 1)
this->StopPlayback();
break;
// Copy the mouse or keyboard event to the EVENTMSG structure in lParam.
case HC_GETNEXT:
if (!playback_enabled)
break;
memcpy(reinterpret_cast<void*>(lParam), &playback_msg_,
sizeof(playback_msg_));
// The return value is the amount of time (in milliseconds) to wait
// before playing back the next message in the playback queue. Each
// time this is called, we recalculate the delay relative to our current
// wall clock.
delay = (playback_msg_.time - playback_first_msg_time_) -
(timeGetTime() - playback_start_time_);
if (delay < 0)
delay = 0;
return delay;
// An application has called PeekMessage with wRemoveMsg set to PM_NOREMOVE
// indicating that the message is not removed from the message queue after
// PeekMessage processing.
case HC_NOREMOVE:
break;
}
return CallNextHookEx(journal_hook_, nCode, wParam, lParam);
}
} // namespace base
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