SetClipboardData requires a memory object allocated with `GMEM_MOVE…

…ABLE` (and locks) (#8490)

* SetClipboardData requires a memory object allocated with GMEM_MOVEABLE (and locks)

* Use memmove instead of wcscpy

* We need a str, not bytes

* Remove old comment

kivy/core/clipboard/clipboard_winctypes.py

@@ -18,29 +18,52 @@
 c_char_p = ctypes.c_char_p
 c_wchar_p = ctypes.c_wchar_p
 
+GlobalLock = kernel32.GlobalLock
+GlobalLock.argtypes = [wintypes.HGLOBAL]
+GlobalLock.restype = wintypes.LPVOID
+
+GlobalUnlock = kernel32.GlobalUnlock
+GlobalUnlock.argtypes = [wintypes.HGLOBAL]
+GlobalUnlock.restype = wintypes.BOOL
+
+CF_UNICODETEXT = 13
+GMEM_MOVEABLE = 0x0002
+
 
 class ClipboardWindows(ClipboardBase):
 
+    def _copy(self, data):
+        self._ensure_clipboard()
+        self.put(data, self._clip_mime_type)
+
     def get(self, mimetype='text/plain'):
         GetClipboardData = user32.GetClipboardData
         GetClipboardData.argtypes = [wintypes.UINT]
         GetClipboardData.restype = wintypes.HANDLE
 
         user32.OpenClipboard(user32.GetActiveWindow())
-        # Standard Clipboard Format "1" is "CF_TEXT"
-        pcontents = GetClipboardData(13)
+
+        # GetClipboardData returns a HANDLE to the clipboard data
+        # which is a memory object containing the data
+        # See: https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-getclipboarddata  # noqa: E501
+        pcontents = GetClipboardData(CF_UNICODETEXT)
 
         # if someone pastes a FILE, the content is None for SCF 13
         # and the clipboard is locked if not closed properly
         if not pcontents:
             user32.CloseClipboard()
             return ''
-        data = c_wchar_p(pcontents).value.encode(self._encoding)
+
+        # The handle returned by GetClipboardData is a memory object
+        # and needs to be locked to get the actual pointer to the data
+        pcontents_locked = GlobalLock(pcontents)
+        data = c_wchar_p(pcontents_locked).value
+        GlobalUnlock(pcontents)
+
         user32.CloseClipboard()
         return data
 
-    def put(self, text, mimetype='text/plain'):
-
+    def put(self, text, mimetype="text/plain"):
         SetClipboardData = user32.SetClipboardData
         SetClipboardData.argtypes = [wintypes.UINT, wintypes.HANDLE]
         SetClipboardData.restype = wintypes.HANDLE
@@ -52,20 +75,31 @@ def put(self, text, mimetype='text/plain'):
         user32.OpenClipboard(user32.GetActiveWindow())
         user32.EmptyClipboard()
 
-        # this allocates memory for the string and returns a handle to it
-        # allocates fixed memory, len + 2 is for the null character
-        # no need to  call GlobalFree here as SetClipboardData will do for you
-        # noqa: E501 see: https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-setclipboarddata#parameters
-        GMEM_FIXED = 0x0000
-        hCd = GlobalAlloc(GMEM_FIXED, len(text) + 2)
-
-        # copy the string into the allocated memory
-        msvcrt.wcscpy(c_wchar_p(hCd), text)
-
-        # standard clipboard format for unicode text
-        # noqa: E501 see https://learn.microsoft.com/en-us/windows/win32/dataxchg/standard-clipboard-formats#constants
-        CF_UNICODETEXT = 13
-        # set the clipboard data, later used by GetClipboardData()
+        # The wsclen function returns the number of
+        # wide characters in a string (not including the null character)
+        text_len = msvcrt.wcslen(text) + 1
+
+        # According to the docs regarding SetClipboardDatam, if the hMem
+        # parameter identifies a memory object, the object must have
+        # been allocated using the GMEM_MOVEABLE flag.
+        # See: https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-setclipboarddata  # noqa: E501
+        # The size of the memory object is the number of wide characters in
+        # the string plus one for the terminating null character
+        hCd = GlobalAlloc(
+            GMEM_MOVEABLE, ctypes.sizeof(ctypes.c_wchar) * text_len
+        )
+
+        # Since the memory object is allocated with GMEM_MOVEABLE, should be
+        # locked to get the actual pointer to the data.
+        hCd_locked = GlobalLock(hCd)
+        ctypes.memmove(
+            c_wchar_p(hCd_locked),
+            c_wchar_p(text),
+            ctypes.sizeof(ctypes.c_wchar) * text_len,
+        )
+        GlobalUnlock(hCd)
+
+        # Finally, set the clipboard data (and then close the clipboard)
         SetClipboardData(CF_UNICODETEXT, hCd)
         user32.CloseClipboard()