laywerrobot/lib/python3.6/site-packages/pandas/io/clipboard/windows.py
2020-08-27 21:55:39 +02:00

153 lines
5.3 KiB
Python

"""
This module implements clipboard handling on Windows using ctypes.
"""
import time
import contextlib
import ctypes
from ctypes import c_size_t, sizeof, c_wchar_p, get_errno, c_wchar
from .exceptions import PyperclipWindowsException
class CheckedCall(object):
def __init__(self, f):
super(CheckedCall, self).__setattr__("f", f)
def __call__(self, *args):
ret = self.f(*args)
if not ret and get_errno():
raise PyperclipWindowsException("Error calling " + self.f.__name__)
return ret
def __setattr__(self, key, value):
setattr(self.f, key, value)
def init_windows_clipboard():
from ctypes.wintypes import (HGLOBAL, LPVOID, DWORD, LPCSTR, INT, HWND,
HINSTANCE, HMENU, BOOL, UINT, HANDLE)
windll = ctypes.windll
safeCreateWindowExA = CheckedCall(windll.user32.CreateWindowExA)
safeCreateWindowExA.argtypes = [DWORD, LPCSTR, LPCSTR, DWORD, INT, INT,
INT, INT, HWND, HMENU, HINSTANCE, LPVOID]
safeCreateWindowExA.restype = HWND
safeDestroyWindow = CheckedCall(windll.user32.DestroyWindow)
safeDestroyWindow.argtypes = [HWND]
safeDestroyWindow.restype = BOOL
OpenClipboard = windll.user32.OpenClipboard
OpenClipboard.argtypes = [HWND]
OpenClipboard.restype = BOOL
safeCloseClipboard = CheckedCall(windll.user32.CloseClipboard)
safeCloseClipboard.argtypes = []
safeCloseClipboard.restype = BOOL
safeEmptyClipboard = CheckedCall(windll.user32.EmptyClipboard)
safeEmptyClipboard.argtypes = []
safeEmptyClipboard.restype = BOOL
safeGetClipboardData = CheckedCall(windll.user32.GetClipboardData)
safeGetClipboardData.argtypes = [UINT]
safeGetClipboardData.restype = HANDLE
safeSetClipboardData = CheckedCall(windll.user32.SetClipboardData)
safeSetClipboardData.argtypes = [UINT, HANDLE]
safeSetClipboardData.restype = HANDLE
safeGlobalAlloc = CheckedCall(windll.kernel32.GlobalAlloc)
safeGlobalAlloc.argtypes = [UINT, c_size_t]
safeGlobalAlloc.restype = HGLOBAL
safeGlobalLock = CheckedCall(windll.kernel32.GlobalLock)
safeGlobalLock.argtypes = [HGLOBAL]
safeGlobalLock.restype = LPVOID
safeGlobalUnlock = CheckedCall(windll.kernel32.GlobalUnlock)
safeGlobalUnlock.argtypes = [HGLOBAL]
safeGlobalUnlock.restype = BOOL
GMEM_MOVEABLE = 0x0002
CF_UNICODETEXT = 13
@contextlib.contextmanager
def window():
"""
Context that provides a valid Windows hwnd.
"""
# we really just need the hwnd, so setting "STATIC"
# as predefined lpClass is just fine.
hwnd = safeCreateWindowExA(0, b"STATIC", None, 0, 0, 0, 0, 0,
None, None, None, None)
try:
yield hwnd
finally:
safeDestroyWindow(hwnd)
@contextlib.contextmanager
def clipboard(hwnd):
"""
Context manager that opens the clipboard and prevents
other applications from modifying the clipboard content.
"""
# We may not get the clipboard handle immediately because
# some other application is accessing it (?)
# We try for at least 500ms to get the clipboard.
t = time.time() + 0.5
success = False
while time.time() < t:
success = OpenClipboard(hwnd)
if success:
break
time.sleep(0.01)
if not success:
raise PyperclipWindowsException("Error calling OpenClipboard")
try:
yield
finally:
safeCloseClipboard()
def copy_windows(text):
# This function is heavily based on
# http://msdn.com/ms649016#_win32_Copying_Information_to_the_Clipboard
with window() as hwnd:
# http://msdn.com/ms649048
# If an application calls OpenClipboard with hwnd set to NULL,
# EmptyClipboard sets the clipboard owner to NULL;
# this causes SetClipboardData to fail.
# => We need a valid hwnd to copy something.
with clipboard(hwnd):
safeEmptyClipboard()
if text:
# http://msdn.com/ms649051
# If the hMem parameter identifies a memory object,
# the object must have been allocated using the
# function with the GMEM_MOVEABLE flag.
count = len(text) + 1
handle = safeGlobalAlloc(GMEM_MOVEABLE,
count * sizeof(c_wchar))
locked_handle = safeGlobalLock(handle)
ctypes.memmove(c_wchar_p(locked_handle),
c_wchar_p(text), count * sizeof(c_wchar))
safeGlobalUnlock(handle)
safeSetClipboardData(CF_UNICODETEXT, handle)
def paste_windows():
with clipboard(None):
handle = safeGetClipboardData(CF_UNICODETEXT)
if not handle:
# GetClipboardData may return NULL with errno == NO_ERROR
# if the clipboard is empty.
# (Also, it may return a handle to an empty buffer,
# but technically that's not empty)
return ""
return c_wchar_p(handle).value
return copy_windows, paste_windows