error handling

remove some TODOs

canvas.cpp

@@ -13,7 +13,8 @@ int Canvas::sig_fd[2];
 Canvas::Canvas(ResourceManager *_res, QWidget *parent) :
 		QWidget(parent),
 		res(_res),
-		draw_overlay(true) {
+		draw_overlay(true),
+		valid(true) {
 	setFocusPolicy(Qt::StrongFocus);
 	res->set_canvas(this);
 
@@ -22,7 +23,9 @@ Canvas::Canvas(ResourceManager *_res, QWidget *parent) :
 	// setup signal handling
 	if (socketpair(AF_UNIX, SOCK_STREAM, 0, sig_fd) == -1) {
 		cerr << "socketpair: " << strerror(errno) << endl;
-		// TODO exit
+		valid = false;
+		sig_notifier = NULL;
+		return;
 	}
 	sig_notifier = new QSocketNotifier(sig_fd[1], QSocketNotifier::Read, this);
 	connect(sig_notifier, SIGNAL(activated(int)), this, SLOT(handle_signal()));
@@ -34,7 +37,8 @@ Canvas::Canvas(ResourceManager *_res, QWidget *parent) :
 
 	if (sigaction(SIGUSR1, &usr, 0) > 0) {
 		cerr << "sigaction: " << strerror(errno) << endl;
-		// TODO exit
+		valid = false;
+		return;
 	}
 
 	// prints the string representation of a key
@@ -84,6 +88,10 @@ Canvas::~Canvas() {
 	delete layout;
 }
 
+bool Canvas::is_valid() const {
+	return valid;
+}
+
 void Canvas::signal_handler(int /*unused*/) {
 	char tmp = '1';
 	if (write(sig_fd[0], &tmp, sizeof(char)) < 0) {

canvas.h

@@ -33,6 +33,7 @@ public:
 	Canvas(ResourceManager *res, QWidget *parent = 0);
 	~Canvas();
 
+	bool is_valid() const;
 	// signal handling
 	static void signal_handler(int unused);
 public slots:
@@ -88,6 +89,7 @@ private:
 	// signal handling
 	static int sig_fd[2];
 	QSocketNotifier *sig_notifier;
+	bool valid;
 
 };
 

layout.cpp

@@ -34,7 +34,7 @@ void Layout::resize(int w, int h) {
 }
 
 void Layout::set_zoom(int /*new_zoom*/, bool /*relative*/) {
-	// TODO implement in all the child classes
+	// implement in child classes where necessary
 }
 
 void Layout::set_columns(int /*new_columns*/, bool /*relative*/) {
@@ -216,7 +216,6 @@ void GridLayout::set_constants() {
 
 	// apply zoom value
 	size *= (1 + zoom * ZOOM_FACTOR);
-	// TODO adjust offset values
 
 	horizontal_page = (page + horizontal_page) % grid->get_column_count();
 	page = page / grid->get_column_count() * grid->get_column_count();

main.cpp

@@ -18,10 +18,13 @@ int main(int argc, char *argv[]) {
 	}
 
 	ResourceManager res(QString::fromUtf8(argv[1]));
-	if (res.is_null()) {
+	if (!res.is_valid()) {
 		return 1;
 	}
 	Viewer katarakt(&res);
+	if (!katarakt.is_valid()) {
+		return 1;
+	}
 	katarakt.show();
 
 	return app.exec();

resourcemanager.cpp

@@ -175,8 +175,8 @@ void ResourceManager::reload_document() {
 	set_canvas(canvas);
 }
 
-bool ResourceManager::is_null() const {
-	return (doc == NULL);
+bool ResourceManager::is_valid() const {
+	return (doc != NULL);
 }
 
 void ResourceManager::set_canvas(Canvas *c) {

resourcemanager.h

@@ -44,8 +44,8 @@ public:
 
 	void reload_document();
 
-	// document not open?
-	bool is_null() const;
+	// document opened correctly?
+	bool is_valid() const;
 
 	// page (meta)data
 	QImage *get_page(int page, int newWidth);

viewer.cpp

@@ -2,8 +2,15 @@
 
 
 Viewer::Viewer(ResourceManager *res, QWidget *parent) :
-		QWidget(parent) {
+		QWidget(parent),
+		valid(true) {
 	canvas = new Canvas(res, this);
+	if (!canvas->is_valid()) {
+		valid = false;
+		search_bar = NULL;
+		layout = NULL;
+		return;
+	}
 
 	search_bar = new QLineEdit(this);
 	// TODO these sequences conflict between widgets
@@ -29,6 +36,10 @@ Viewer::~Viewer() {
 	delete canvas;
 }
 
+bool Viewer::is_valid() const {
+	return valid;
+}
+
 void Viewer::focus_search() {
 	search_bar->setFocus(Qt::OtherFocusReason);
 	search_bar->selectAll();

viewer.h

@@ -20,6 +20,7 @@ public:
 	Viewer(ResourceManager *res, QWidget *parent = 0);
 	~Viewer();
 
+	bool is_valid() const;
 	void focus_search();
 
 protected:
@@ -36,6 +37,7 @@ private:
 
 	// key sequences
 	std::map<QKeySequence,func_t> sequences;
+	bool valid;
 };
 
 #endif