Add basic dbus-API for synctex support

Katarakt now exposes a dbus-API that allows TeX-editors to synchronize
the positions in source code and pdf via synctex.

TODO: The API allows to specify positions in the PDF as (page,x,y)
triple, but the x,y coordinates are currently ignored or set to 0,
respectively. We need more katarakt-internal API for this to be
implementable.

katarakt.pro

@@ -3,7 +3,7 @@ TARGET = katarakt
 DEPENDPATH += .
 INCLUDEPATH += .
 CONFIG += qt
-QT += network xml
+QT += network xml dbus
 
 DEFINES += "POPPLER_VERSION_MAJOR=`pkg-config --modversion poppler-qt4 | cut -d . -f 1`"
 DEFINES += "POPPLER_VERSION_MINOR=`pkg-config --modversion poppler-qt4 | cut -d . -f 2`"
@@ -13,11 +13,15 @@ QMAKE_CXXFLAGS_DEBUG += -DDEBUG
 
 # Input
 HEADERS +=  src/layout/layout.h src/layout/presentationlayout.h src/layout/gridlayout.h src/layout/presenterlayout.h \
-            src/viewer.h src/canvas.h src/resourcemanager.h src/grid.h src/search.h src/gotoline.h src/config.h src/download.h src/util.h src/kpage.h src/worker.h src/beamerwindow.h src/toc.h src/splitter.h src/selection.h
+            src/viewer.h src/canvas.h src/resourcemanager.h src/grid.h src/search.h src/gotoline.h src/config.h \
+            src/download.h src/util.h src/kpage.h src/worker.h src/beamerwindow.h src/toc.h src/splitter.h src/selection.h \
+            src/dbus/source_correlate.h src/dbus/dbus.h
 
 SOURCES +=  src/main.cpp \
             src/layout/layout.cpp src/layout/presentationlayout.cpp src/layout/gridlayout.cpp src/layout/presenterlayout.cpp \
-            src/viewer.cpp src/canvas.cpp src/resourcemanager.cpp src/grid.cpp src/search.cpp src/gotoline.cpp src/config.cpp src/download.cpp src/util.cpp src/kpage.cpp src/worker.cpp src/beamerwindow.cpp src/toc.cpp src/splitter.cpp src/selection.cpp
+            src/viewer.cpp src/canvas.cpp src/resourcemanager.cpp src/grid.cpp src/search.cpp src/gotoline.cpp src/config.cpp \
+            src/download.cpp src/util.cpp src/kpage.cpp src/worker.cpp src/beamerwindow.cpp src/toc.cpp src/splitter.cpp \
+            src/selection.cpp src/dbus/source_correlate.cpp src/dbus/dbus.cpp
 unix:LIBS += -lpoppler-qt4
 
 documentation.target = doc/katarakt.1

src/canvas.cpp

@@ -193,7 +193,14 @@ void Canvas::mousePressEvent(QMouseEvent *event) {
 }
 
 void Canvas::mouseReleaseEvent(QMouseEvent *event) {
-	if (click_link_button != Qt::NoButton && event->button() == click_link_button) {
+	if (event->button() == Qt::LeftButton && event->modifiers() == Qt::ControlModifier) {
+		// emit synctex signal
+
+		int page = cur_layout->get_page();
+		// FIXME Really get the page that was clicked on
+		// FIXME Get coordinates
+		emit synchronize_editor(page, 0, 0);
+	} else if (click_link_button != Qt::NoButton && event->button() == click_link_button) {
 		if (mx_down == event->x() && my_down == event->y()) {
 			int page = cur_layout->get_page();
 			pair<int, QPointF> location = cur_layout->get_location_at(mx_down, my_down);

src/canvas.h

@@ -43,6 +43,13 @@ protected:
 	void mouseDoubleClickEvent(QMouseEvent * event);
 	void resizeEvent(QResizeEvent *event);
 
+signals:
+	/**
+	 * Emitted when the user requests to see the source code of a
+	 * particular point on a particular page.
+	 */
+	void synchronize_editor(int page, int x, int y);
+
 private slots:
 	void page_rendered(int page);
 	void goto_page();

src/dbus/dbus.cpp

+#include "dbus.h"
+#include "source_correlate.h"
+#include "../viewer.h"
+
+#include <QDBusConnection>
+#include <QApplication>
+
+#include <iostream>
+
+using namespace std;
+
+void dbus_init(Viewer *viewer)
+{
+	/* Add dbus interfaces to the viewer object.
+	 *
+	 * These are automatically destroyed, if the parent object is.
+	 *
+	 * At present, there is only the SourceCorrelate interface.
+	 */
+	new SourceCorrelate(viewer);
+
+	QString bus_name = QString("katarakt.pid%1")
+	                     .arg(QApplication::applicationPid());
+
+	if (!QDBusConnection::sessionBus().registerService(bus_name)) {
+#ifdef DEBUG
+		cerr << "Failed to register DBus service" << endl;
+#endif	
+	} else {
+		if (!QDBusConnection::sessionBus().registerObject("/", viewer)) {
+#ifdef DEBUG
+			cerr << "Failed to register viewer object on DBus" << endl;
+#endif
+		}
+	}
+}

src/dbus/dbus.h

+#ifndef DBUS_H
+#define DBUS_H
+
+class Viewer;
+
+/**
+ * Connect to the session bus and publish all interfaces.
+ *
+ * Fails silently in case of errors.
+ */
+void dbus_init(Viewer *viewer);
+
+#endif /* DBUS_H */

src/dbus/source_correlate.cpp

+#include "source_correlate.h"
+
+#include "../viewer.h"
+#include "../canvas.h"
+#include "../layout/layout.h"
+#include "../resourcemanager.h"
+
+#include <QUrl>
+#include <QFileInfo>
+
+using namespace std;
+
+SourceCorrelate::SourceCorrelate(Viewer *viewer)
+	: QDBusAbstractAdaptor(viewer), viewer(viewer)
+{
+	connect(viewer->get_canvas(), SIGNAL(synchronize_editor(int, int, int)),
+	        this, SLOT(emit_edit_signal(int, int, int)));
+}	
+
+void SourceCorrelate::view(QString filename, int page, int x, int y)
+{
+	if (page < 0)
+		return;
+	
+	QFileInfo oldFile = QFileInfo(viewer->get_res()->get_file());
+	QFileInfo newFile = QFileInfo(filename);
+	QUrl url(filename);
+	if ((url.isLocalFile() || url.isRelative())
+	    && newFile.canonicalFilePath() != oldFile.canonicalFilePath()) {
+		// only open, if file is different from the already loaded one
+		viewer->open(filename);
+	}
+
+	// needed to add an entry to the jump list
+	int current_page = viewer->get_canvas()->get_layout()->get_page();
+
+	viewer->get_canvas()->get_layout()->scroll_page(page, false);
+	// FIXME scroll to offset
+	viewer->get_res()->store_jump(current_page);
+	viewer->get_canvas()->repaint();
+	viewer->repaint();
+}
+
+void SourceCorrelate::emit_edit_signal(int page, int x, int y)
+{
+	QString file = viewer->get_res()->get_file();
+	qDebug("Emitting the edit signal");
+	emit edit(file, page, x, y);
+}

src/dbus/source_correlate.h

+#ifndef SOURCE_CORRELATE_H
+#define SOURCE_CORRELATE_H
+
+#include <QDBusAbstractAdaptor>
+
+class Viewer;
+
+class SourceCorrelate : public QDBusAbstractAdaptor {
+	Q_OBJECT;
+	Q_CLASSINFO("D-Bus Interface", "katarakt.SourceCorrelate");
+
+public:
+	SourceCorrelate(Viewer *viewer);
+
+public slots: 
+	/** Jump to a (0 indexed) page in file filename and make the position
+	 * (x,y) in points from the top left corner of page visible.
+	 *
+	 * The document will not be reloaded if the filename is the same as
+	 * the currently loaded file.
+	 */
+	void view(QString filename, int page, int x, int y);
+
+signals:
+	/** Emitted, if the user requests to edit the source code for a
+	 *  specific position on a specific page.
+	 * 
+	 * The page is 0-indexed.
+	 */
+	void edit(QString filename, int page, int x, int y);
+
+private slots:
+	void emit_edit_signal(int page, int x, int y);
+
+private:
+        Viewer *viewer;
+};
+
+#endif /* SOURCE_CORRELATE_H */

src/main.cpp

@@ -7,6 +7,7 @@
 #include "resourcemanager.h"
 #include "viewer.h"
 #include "config.h"
+#include "dbus/dbus.h"
 
 using namespace std;
 
@@ -94,6 +95,9 @@ int main(int argc, char *argv[]) {
 	}
 	katarakt.show();
 
+	// initialize dbus interfaces
+	dbus_init(&katarakt);
+
 	return app.exec();
 }