* proper mechanism to dispatch FuncRequests delayed, i.e. when the event loop is idle again

* fixes http://bugzilla.lyx.org/show_bug.cgi?id=5447

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@27459 a592a061-630c-0410-9148-cb99ea01b6c8

src/frontends/qt4/GuiApplication.cpp

@@ -62,6 +62,8 @@
 #include "support/linkback/LinkBackProxy.h"
 #endif
 
+#include <queue>
+
 #include <QByteArray>
 #include <QClipboard>
 #include <QDateTime>
@@ -178,16 +180,6 @@ vector<string> loadableImageFormats()
 }
 
 
-class FuncRequestEvent : public QEvent
-{
-public:
-       FuncRequestEvent(FuncRequest const & req) 
-       : QEvent(QEvent::User), request(req) {}
-
-       FuncRequest const request;
-};
-
-
 ////////////////////////////////////////////////////////////////////////
 // Icon loading support code.
 ////////////////////////////////////////////////////////////////////////
@@ -631,6 +623,9 @@ struct GuiApplication::Private
 	/// are done.
 	QTimer general_timer_;
 
+	/// delayed FuncRequests
+	std::queue<FuncRequest> func_request_queue_;
+
 	/// Multiple views container.
 	/**
 	* Warning: This must not be a smart pointer as the destruction of the
@@ -907,6 +902,13 @@ bool GuiApplication::dispatch(FuncRequest const & cmd)
 }
 
 
+void GuiApplication::dispatchDelayed(FuncRequest const & func)
+{
+	d->func_request_queue_.push(func);
+	QTimer::singleShot(0, this, SLOT(processFuncRequestQueue()));
+}
+
+
 void GuiApplication::resetGui()
 {
 	// Set the language defined by the user.
@@ -1088,6 +1090,15 @@ void GuiApplication::setGuiLanguage()
 }
 
 
+void GuiApplication::processFuncRequestQueue()
+{
+	while (!d->func_request_queue_.empty()) {
+		lyx::dispatch(d->func_request_queue_.back());
+		d->func_request_queue_.pop();
+	}
+}
+
+
 void GuiApplication::execBatchCommands()
 {
 	setGuiLanguage();
@@ -1192,13 +1203,6 @@ void GuiApplication::handleRegularEvents()
 }
 
 
-void GuiApplication::customEvent(QEvent * event)
-{
-       FuncRequestEvent * reqEv = static_cast<FuncRequestEvent *>(event);
-       lyx::dispatch(reqEv->request);
-}
-
-
 bool GuiApplication::event(QEvent * e)
 {
 	switch(e->type()) {
@@ -1209,8 +1213,7 @@ bool GuiApplication::event(QEvent * e)
 		// commands are not executed here yet and the gui is not ready
 		// therefore.
 		QFileOpenEvent * foe = static_cast<QFileOpenEvent *>(e);
-		postEvent(this, new FuncRequestEvent(FuncRequest(LFUN_FILE_OPEN,
-			qstring_to_ucs4(foe->file()))));
+		dispatchDelayed(FuncRequest(LFUN_FILE_OPEN, qstring_to_ucs4(foe->file())));
 		e->accept();
 		return true;
 	}

src/frontends/qt4/GuiApplication.h

@@ -59,6 +59,7 @@ public:
 	//@{
 	bool getStatus(FuncRequest const & cmd, FuncStatus & flag) const;
 	bool dispatch(FuncRequest const &);
+	void dispatchDelayed(FuncRequest const &);
 	void resetGui();
 	void restoreGuiSession();
 	Clipboard & clipboard();
@@ -66,7 +67,6 @@ public:
 	FontLoader & fontLoader();
 	int exec();
 	void exit(int status);
-	void customEvent(QEvent * event);
 	bool event(QEvent * e);
 	bool getRgbColor(ColorCode col, RGBColor & rgbcol);
 	std::string const hexName(ColorCode col);
@@ -135,6 +135,9 @@ private Q_SLOTS:
 	///
 	void onLastWindowClosed();
 
+	///
+	void processFuncRequestQueue();
+
 private:
 	///
 	bool closeAllViews();

src/frontends/qt4/GuiView.cpp

@@ -142,6 +142,7 @@ private:
 	QPixmap splash_;
 };
 
+
 /// Toolbar store providing access to individual toolbars by name.
 typedef std::map<std::string, GuiToolbar *> ToolbarMap;
 
@@ -597,7 +598,7 @@ void GuiView::dragEnterEvent(QDragEnterEvent * event)
 }
 
 
-void GuiView::dropEvent(QDropEvent* event)
+void GuiView::dropEvent(QDropEvent * event)
 {
 	QList<QUrl> files = event->mimeData()->urls();
 	if (files.isEmpty())
@@ -607,8 +608,13 @@ void GuiView::dropEvent(QDropEvent* event)
 	for (int i = 0; i != files.size(); ++i) {
 		string const file = os::internal_path(fromqstr(
 			files.at(i).toLocalFile()));
-		if (!file.empty())
-			lyx::dispatch(FuncRequest(LFUN_FILE_OPEN, file));
+		if (!file.empty()) {
+			// Asynchronously post the event. DropEvent usually come
+			// from the BufferView. But reloading a file might close
+			// the BufferView from within its own event handler.
+			guiApp->dispatchDelayed(FuncRequest(LFUN_FILE_OPEN, file));
+			event->accept();
+		}
 	}
 }