Fix slowness issue with Clipboard. Cache the Clipboard status when the data is changed.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@20617 a592a061-630c-0410-9148-cb99ea01b6c8

src/frontends/qt4/GuiClipboard.cpp

@@ -36,6 +36,15 @@ static char const * const mime_type = "application/x-lyx";
 namespace lyx {
 namespace frontend {
 
+GuiClipboard::GuiClipboard()
+{
+	connect(qApp->clipboard(), SIGNAL(dataChanged()),
+		this, SLOT(on_dataChanged()));
+	// initialize clipboard status.
+	on_dataChanged()
+}
+
+
 string const GuiClipboard::getAsLyX() const
 {
 	LYXERR(Debug::ACTION) << "GuiClipboard::getAsLyX(): `";
@@ -110,16 +119,27 @@ bool GuiClipboard::isInternal() const
 }
 
 
+void GuiClipboard::on_dataChanged()
+{
+	text_clipboard_empty_ = qApp->clipboard()->
+		text(QClipboard::Clipboard).isEmpty();
+
+	has_lyx_contents_ = hasLyXContents();
+}
+
+
 bool GuiClipboard::empty() const
 {
 	// We need to check both the plaintext and the LyX version of the
 	// clipboard. The plaintext version is empty if the LyX version
-	// contains only one inset, and the LyX version is empry if the
+	// contains only one inset, and the LyX version is empty if the
 	// clipboard does not come from LyX.
-	if (!qApp->clipboard()->text(QClipboard::Clipboard).isEmpty())
+	if (!text_clipboard_empty_)
 		return false;
-	return !hasLyXContents();
+	return !has_lyx_contents_;
 }
 
 } // namespace frontend
 } // namespace lyx
+
+#include "GuiClipboard_moc.cpp"

src/frontends/qt4/GuiClipboard.h

@@ -16,15 +16,19 @@
 
 #include "frontends/Clipboard.h"
 
+#include <QObject>
+
 namespace lyx {
 namespace frontend {
 
 /**
  * The Qt4 version of the Clipboard.
  */
-class GuiClipboard : public Clipboard
+class GuiClipboard: public QObject, public Clipboard
 {
+	Q_OBJECT
 public:
+	GuiClipboard();
 	virtual ~GuiClipboard() {}
 
 	/** Clipboard overloaded methods
@@ -37,6 +41,13 @@ public:
 	bool isInternal() const;
 	bool empty() const;
 	//@}
+
+private Q_SLOTS:
+	void on_dataChanged();
+
+private:
+	bool text_clipboard_empty_;
+	bool has_lyx_contents_;
 };
 
 } // namespace frontend

src/frontends/qt4/Makefile.am

@@ -117,7 +117,6 @@ SOURCEFILES = \
 
 NOMOCHEADER = \
 	ButtonController.h \
-	GuiClipboard.h \
 	GuiFontLoader.h \
 	GuiFontMetrics.h \
 	GuiSelection.h \
@@ -143,6 +142,7 @@ MOCHEADER = \
 	GuiChanges.h \
 	GuiCharacter.h \
 	GuiCitation.h \
+	GuiClipboard.h \
 	GuiCommandBuffer.h \
 	GuiCommandEdit.h \
 	GuiDelimiter.h \