Fix history behaviour

When starting in A/B, then manually going up to A,
and back down to A/B, going back in history to A was impossible,
because it would actually end up being a /forward/ entry.

fiv.c

@@ -700,49 +700,28 @@ update_files_index(void)
 }
 
 static void
-load_directory_without_reload(const char *uri)
+change_directory_without_reload(const char *uri)
 {
-	gchar *uri_duplicated = g_strdup(uri);
-	if (g.directory_back && !strcmp(uri, g.directory_back->data)) {
-		// We're going back in history.
 	if (g.directory) {
-			g.directory_forward =
-				g_list_prepend(g.directory_forward, g.directory);
-			g.directory = NULL;
-		}
+		// Note that this function can be passed g.directory directly.
+		if (!strcmp(uri, g.directory))
+			return;
 
-		GList *link = g.directory_back;
-		g.directory_back = g_list_remove_link(g.directory_back, link);
-		g_list_free_full(link, g_free);
-	} else if (g.directory_forward && !strcmp(uri, g.directory_forward->data)) {
-		// We're going forward in history.
-		if (g.directory) {
-			g.directory_back =
-				g_list_prepend(g.directory_back, g.directory);
-			g.directory = NULL;
-		}
-
-		GList *link = g.directory_forward;
-		g.directory_forward = g_list_remove_link(g.directory_forward, link);
-		g_list_free_full(link, g_free);
-	} else if (g.directory && strcmp(uri, g.directory)) {
 		// We're on a new subpath.
 		g_list_free_full(g.directory_forward, g_free);
 		g.directory_forward = NULL;
 
 		g.directory_back = g_list_prepend(g.directory_back, g.directory);
-		g.directory = NULL;
 	}
 
-	g_free(g.directory);
-	g.directory = uri_duplicated;
+	g.directory = g_strdup(uri);
 }
 
 static void
 load_directory_without_switching(const char *uri)
 {
 	if (uri) {
-		load_directory_without_reload(uri);
+		change_directory_without_reload(uri);
 
 		GtkAdjustment *vadjustment = gtk_scrolled_window_get_vadjustment(
 			GTK_SCROLLED_WINDOW(g.browser_scroller));
@@ -768,9 +747,6 @@ load_directory(const char *uri)
 {
 	load_directory_without_switching(uri);
 
-	// XXX: When something outside the filtered entries is open, the index is
-	// kept at -1, and browsing doesn't work. How to behave here?
-	// Should we add it to the pointer array as an exception?
 	if (uri) {
 		switch_to_browser_noselect();
 
@@ -779,6 +755,46 @@ load_directory(const char *uri)
 	}
 }
 
+static void
+go_back(void)
+{
+	if (gtk_stack_get_visible_child(GTK_STACK(g.stack)) == g.view_box) {
+		switch_to_browser_noselect();
+	} else if (g.directory_back) {
+		if (g.directory)
+			g.directory_forward =
+				g_list_prepend(g.directory_forward, g.directory);
+
+		const gchar *uri = g.directory = g.directory_back->data;
+
+		GList *link = g.directory_back;
+		g.directory_back = g_list_remove_link(g.directory_back, link);
+		g_list_free(link);
+
+		load_directory(uri);
+	}
+}
+
+static void
+go_forward(void)
+{
+	if (g.directory_forward) {
+		if (g.directory)
+			g.directory_back =
+				g_list_prepend(g.directory_back, g.directory);
+
+		const gchar *uri = g.directory = g.directory_forward->data;
+
+		GList *link = g.directory_forward;
+		g.directory_forward = g_list_remove_link(g.directory_forward, link);
+		g_list_free(link);
+
+		load_directory(uri);
+	} else if (g.uri) {
+		switch_to_view();
+	}
+}
+
 static void
 on_model_files_changed(FivIoModel *model, G_GNUC_UNUSED gpointer user_data)
 {
@@ -877,6 +893,10 @@ open_image(const char *uri)
 		update_files_index();
 	g_free(parent);
 
+	// XXX: When something outside currently filtered entries is open,
+	// g.files_index is kept at -1, and browsing doesn't work.
+	// How to behave here?
+
 	switch_to_view();
 }
 
@@ -1399,16 +1419,10 @@ on_key_press(G_GNUC_UNUSED GtkWidget *widget, GdkEventKey *event,
 	case GDK_MOD1_MASK:
 		switch (event->keyval) {
 		case GDK_KEY_Left:
-			if (gtk_stack_get_visible_child(GTK_STACK(g.stack)) == g.view_box)
-				switch_to_browser_noselect();
-			else if (g.directory_back)
-				load_directory(g.directory_back->data);
+			go_back();
 			return TRUE;
 		case GDK_KEY_Right:
-			if (g.directory_forward)
-				load_directory(g.directory_forward->data);
-			else if (g.uri)
-				switch_to_view();
+			go_forward();
 			return TRUE;
 		}
 		break;
@@ -1570,7 +1584,7 @@ on_button_press_view(G_GNUC_UNUSED GtkWidget *widget, GdkEventButton *event)
 	switch (event->button) {
 	case 4:  // back (GdkWin32, GdkQuartz)
 	case 8:  // back
-		switch_to_browser_noselect();
+		go_back();
 		return TRUE;
 	case GDK_BUTTON_PRIMARY:
 		if (event->type == GDK_2BUTTON_PRESS) {
@@ -1592,15 +1606,11 @@ on_button_press_browser_paned(
 	switch (event->button) {
 	case 4:  // back (GdkWin32, GdkQuartz)
 	case 8:  // back
-		if (g.directory_back)
-			load_directory(g.directory_back->data);
+		go_back();
 		return TRUE;
 	case 5:  // forward (GdkWin32, GdkQuartz)
 	case 9:  // forward
-		if (g.directory_forward)
-			load_directory(g.directory_forward->data);
-		else if (g.uri)
-			switch_to_view();
+		go_forward();
 		return TRUE;
 	default:
 		return FALSE;