Prepare for external/internal clipboard merging.

* Clipboard.h: new isInternal() pure virtual method
* Selection.h: new isInternal() pure virtual method

* GuiClipboard, GuiSelection: implement new method.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@16476 a592a061-630c-0410-9148-cb99ea01b6c8

src/frontends/Clipboard.h

@@ -39,6 +39,10 @@ public:
 	 * the clipboard.
 	 */
 	virtual void put(docstring const &) = 0;
+
+	/// state of clipboard.
+	/// \retval true if the system clipboard has been set within LyX.
+	virtual bool isInternal() const = 0;
 };
 
 } // namespace frontend

src/frontends/Selection.h

@@ -43,6 +43,10 @@ public:
 	 * This should be called whenever some text is highlighted.
 	 */
 	virtual void put(docstring const &) = 0;
+
+	/// state of clipboard.
+	/// \retval true if the system clipboard has been set within LyX.
+	virtual bool isInternal() const = 0;
 };
 
 } // namespace frontend

src/frontends/qt4/GuiClipboard.C

@@ -50,5 +50,11 @@ void GuiClipboard::put(docstring const & str)
 	                           QClipboard::Clipboard);
 }
 
+
+bool GuiClipboard::isInternal() const
+{
+	return qApp->clipboard()->ownsClipboard();
+}
+
 } // namespace frontend
 } // namespace lyx

src/frontends/qt4/GuiClipboard.h

@@ -32,6 +32,7 @@ public:
 	//@{
 	docstring const get() const;
 	void put(docstring const & str);
+	bool isInternal() const;
 	//@}
 };
 

src/frontends/qt4/GuiSelection.C

@@ -62,5 +62,11 @@ void GuiSelection::put(docstring const & str)
 	                           QClipboard::Selection);
 }
 
+
+bool GuiSelection::isInternal() const
+{
+	return qApp->clipboard()->ownsSelection();
+}
+
 } // namespace frontend
 } // namespace lyx

src/frontends/qt4/GuiSelection.h

@@ -33,6 +33,7 @@ public:
 	void haveSelection(bool own);
 	docstring const get() const;
 	void put(docstring const & str);
+	bool isInternal() const;
 	//@}
 };