# Copyright 2021 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
import logging
import time
import pythoncom
import pywintypes
import win32api
import win32com
import win32com.client
import win32con
import win32gui
import win32process
import winerror
class _MessageQueueAttacher(object):
"""Wrapper class for message queue attachment."""
def __enter__(self):
"""Attaches the current thread to the foreground window's message queue.
This is an old and well known exploit used to bypass Windows Focus
rules:
http://www.google.com/search?q=attachthreadinput+setforegroundwindow
"""
self._active_thread_id = 0
active_hwnd = win32gui.GetForegroundWindow()
if not active_hwnd:
logging.warning('No active window is found.')
return
current_thread_id = win32api.GetCurrentThreadId()
active_thread_id, _ = win32process.GetWindowThreadProcessId(
active_hwnd)
win32process.AttachThreadInput(current_thread_id, active_thread_id, 1)
logging.info('Attached current thread input %s to active thread: %s',
current_thread_id, active_thread_id)
self._active_thread_id = active_thread_id
def __exit__(self, unused_type, unused_value, unused_traceback):
"""Detaches the current thread from the active thread's message queue.
"""
if not self._active_thread_id:
return
current_thread_id = win32api.GetCurrentThreadId()
win32process.AttachThreadInput(current_thread_id,
self._active_thread_id, 0)
logging.info('Detached current thread input %s from thread: %s',
current_thread_id, self._active_thread_id)
def SetForegroundWindow(hwnd):
"""Brings the given window to foreground.
Args:
hwnd: Handle of the window to bring to the foreground.
"""
with _MessageQueueAttacher():
return bool(win32gui.SetForegroundWindow(hwnd))
def FindWindowsWithText(parent, text_to_search):
"""Finds windows with given text.
Args:
parent: Handle to the parent window whose child windows are to be
searched.
text_to_search: Substring to search within Windows text,
case-insensitive.
Returns:
A list of HWND that match the search condition.
"""
class WindowFoundHandler(object):
"""Callback class for window enumeration."""
def __init__(self, text_to_search):
self.result = []
self._text_to_search = text_to_search
def Process(self, handle):
"""Callback function when enumerating a window.
Args:
handle: HWND to the enumerated window.
"""
text = win32gui.GetWindowText(handle).lower()
text_to_search = self._text_to_search.lower()
if text_to_search in text:
self.result.append(handle)
def WinFoundCallback(hwnd, window_found_handler):
window_found_handler.Process(hwnd)
handler = WindowFoundHandler(text_to_search)
try:
win32gui.EnumChildWindows(parent, WinFoundCallback, handler)
except pywintypes.error as e:
logging.info('Error while searching [%s], error: [%s]', text_to_search,
e)
return handler.result
def FindWindowsWithTitle(title_to_search):
"""Finds windows with given title.
Args:
title_to_search: Window title substring to search, case-insensitive.
Returns:
A list of HWND that match the search condition.
"""
desktop_handle = None
return FindWindowsWithText(desktop_handle, title_to_search)
def FindWindow(title, class_name, parent=0, child_after=0):
"""Finds a window of a given title and class.
Args:
title: Title of the window to search.
class_name: Class name of the window to search.
parent: Handle to the parent window whose child windows are to be
searched.
child_after: HWND to a child window. Search begins with the next child
window in the Z order.
Returns:
Handle of the found window, or 0 if not found.
"""
hwnd = 0
try:
hwnd = win32gui.FindWindowEx(int(parent), int(child_after), class_name,
title)
except win32gui.error as err:
if err[0] == winrror.ERROR_INVALID_WINDOW_HANDLE: # Could be closed.
pass
elif err[0] != winrror.ERROR_FILE_NOT_FOUND:
raise err
if hwnd:
win32gui.FlashWindow(hwnd, True)
return hwnd
def FindWindowWithTitleAndText(title, text):
"""Checks if the any window has given title, and child window has the text.
Args:
title: Expected window title.
text: Expected window text substring(in any child window),
case-insensitive.
Returns:
A list how HWND that meets the search condition.
"""
hwnds_title_matched = FindWindowsWithTitle(title)
if not hwnds_title_matched:
logging.info('No window has title: [%s].', title)
hwnds = []
for hwnd in hwnds_title_matched:
if FindWindowsWithText(hwnd, text):
hwnds.append(hwnd)
return hwnds
def WaitForWindow(title, class_name, timeout=30):
"""Waits for window with given title and class to appear.
Args:
title: Windows title to search.
class_name: Class name of the window to search.
timeout: How long should wait before give up.
Returns:
A tuple of (HWND, title) of the found window, or (None, None) otherwise.
"""
logging.info('ui.WaitForWindow("%s", "%s") for %s seconds', title,
class_name, timeout)
hwnd = None
start = time.perf_counter()
stop = start + int(timeout)
while time.perf_counter() < stop:
hwnd = FindWindow(title, class_name)
if hwnd:
elapsed = time.perf_counter() - start
logging.info('Window ["%s"] found in %f seconds', title, elapsed)
return (hwnd, title)
logging.info('Window with title [%s] has not appeared yet.', title)
time.sleep(0.5)
logging.warning('WARNING: (%s,"%s") not found within %f seconds', title,
class_name, timeout)
return (None, None)
def ClickButton(button_hwnd):
"""Clicks a button window by sending a BM_CLICK message.
Per http://msdn2.microsoft.com/en-us/library/bb775985.aspx
"If the button is in a dialog box and the dialog box is not active, the
BM_CLICK message might fail. To ensure success in this situation, call
the SetActiveWindow function to activate the dialog box before sending
the BM_CLICK message to the button."
Args:
button_hwnd: HWND to the button to be clicked.
"""
previous_active_window = win32gui.SetActiveWindow(button_hwnd)
win32gui.PostMessage(button_hwnd, win32con.BM_CLICK, 0, 0)
if previous_active_window:
win32gui.SetActiveWindow(previous_active_window)
def ClickChildButtonWithText(parent_hwnd, button_text):
"""Clicks a child button window with given text.
Args:
parent_hwnd: HWND of the button parent.
button_text: Button windows title.
Returns:
Whether button is clicked.
"""
button_hwnd = FindWindow(button_text, 'Button', parent_hwnd)
if button_hwnd:
logging.debug('Found child button with: %s', button_text)
ClickButton(button_hwnd)
return True
logging.debug('No button with [%s] found.', button_text)
return False
def SendKeyToWindow(hwnd, key_to_press):
"""Sends a key press to the window.
This is a blocking call until all keys are pressed.
Args:
hwnd: handle of the window to press key.
key_to_press: Actual key to send to window. eg.'{Enter}'.
See `window_shell` documentation for key definitions.
"""
try:
window_shell = win32com.client.Dispatch('WScript.Shell')
SetForegroundWindow(hwnd)
window_shell.AppActivate(str(win32gui.GetForegroundWindow()))
window_shell.SendKeys(key_to_press)
logging.info('Sent %s to window %x.', key_to_press, hwnd)
except pywintypes.error as err:
logging.error('Failed to press key: %s', err)
raise
except pythoncom.com_error as err:
logging.error('COM exception occurred: %s, is CoInitialize() called?',
err)
raise
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