Ensure clipboard is closed even if exception occurs while clipboard open.

1 files changed, 25 insertions, 5 deletions

diff --git a/win32/ScintillaWin.cxx b/win32/ScintillaWin.cxx
index 31d1d826f..748560a10 100644
--- a/win32/ScintillaWin.cxx
+++ b/win32/ScintillaWin.cxx
@@ -2749,6 +2749,27 @@ bool OpenClipboardRetry(HWND hwnd) noexcept {
 	return false;
 }
 
+// Ensure every successful OpenClipboard is followed by a CloseClipboard.
+class Clipboard {
+	bool opened = false;
+public:
+	Clipboard(HWND hwnd) noexcept : opened(::OpenClipboardRetry(hwnd)) {
+	}
+	// Deleted so Clipboard objects can not be copied.
+	Clipboard(const Clipboard &) = delete;
+	Clipboard(Clipboard &&) = delete;
+	Clipboard &operator=(const Clipboard &) = delete;
+	Clipboard &operator=(Clipboard &&) = delete;
+	~Clipboard() noexcept {
+		if (opened) {
+			::CloseClipboard();
+		}
+	}
+	constexpr operator bool() const noexcept {
+		return opened;
+	}
+};
+
 bool IsValidFormatEtc(const FORMATETC *pFE) noexcept {
 	return pFE->ptd == nullptr &&
 		(pFE->dwAspect & DVASPECT_CONTENT) != 0 &&
@@ -2764,7 +2785,8 @@ bool SupportedFormat(const FORMATETC *pFE) noexcept {
 }
 
 void ScintillaWin::Paste() {
-	if (!::OpenClipboardRetry(MainHWND())) {
+	Clipboard clipboard(MainHWND());
+	if (!clipboard) {
 		return;
 	}
 	UndoGroup ug(pdoc);
@@ -2790,7 +2812,6 @@ void ScintillaWin::Paste() {
 		InsertPasteShape(putf.c_str(), putf.length(), pasteShape);
 		memUSelection.Unlock();
 	}
-	::CloseClipboard();
 	Redraw();
 }
 
@@ -3254,7 +3275,8 @@ void ScintillaWin::CopyToGlobal(GlobalMemory &gmUnicode, const SelectionText &se
 }
 
 void ScintillaWin::CopyToClipboard(const SelectionText &selectedText) {
-	if (!::OpenClipboardRetry(MainHWND())) {
+	Clipboard clipboard(MainHWND());
+	if (!clipboard) {
 		return;
 	}
 	::EmptyClipboard();
@@ -3280,8 +3302,6 @@ void ScintillaWin::CopyToClipboard(const SelectionText &selectedText) {
 		::SetClipboardData(cfLineSelect, 0);
 		::SetClipboardData(cfVSLineTag, 0);
 	}
-
-	::CloseClipboard();
 }
 
 void ScintillaWin::ScrollMessage(WPARAM wParam) {