The Tor Browser: ipc/chromium/src/base/event_recorder.cc@6474c204b198 (annotated)

ipc/chromium/src/base/event_recorder.cc@6474c204b198 (annotated)

ipc/chromium/src/base/event_recorder.cc

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 // Copyright (c) 2006-2008 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 "build/build_config.h"
 #include <windows.h>
 #include <mmsystem.h>
 #include "base/event_recorder.h"
 #include "base/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) {
   CHECK(EventRecorder::current());
   return EventRecorder::current()->RecordWndProc(nCode, wParam, lParam);
 }
 LRESULT CALLBACK StaticPlaybackWndProc(int nCode, WPARAM wParam,
                                        LPARAM lParam) {
   CHECK(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_ == NULL);
   file_ = file_util::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";
     file_util::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);
     file_util::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_ == NULL);
   file_ = file_util::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!";
     file_util::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);
     file_util::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

The Tor Browser / annotate

ipc/chromium/src/base/event_recorder.cc@6474c204b198 (annotated)

ipc/chromium/src/base/event_recorder.cc