new functions to help with implementation of sensitivity code Fix

2005-01-14  Dave Malcolm  <dmalcolm@redhat.com>

	* shell/ev-view.h:
	* shell/ev-view.c (ev_view_can_go_back), (ev_view_can_go_forward):
	new functions to help with implementation of sensitivity code
	* shell/ev-window.c (update_action_sensitivity): Fix sensitivity
	of all actions that might require it.  Fixes a crash when you
	click on the Zoom actions in a window lacking a document.

3 files changed, 90 insertions, 12 deletions

diff --git a/shell/ev-view.c b/shell/ev-view.c
index 41bf94b..8e18ec4 100644
--- a/shell/ev-view.c
+++ b/shell/ev-view.c
@@ -1123,6 +1123,23 @@ go_to_index (EvView *view, int index)
 	go_to_link (view, link);
 }
 
+gboolean
+ev_view_can_go_back (EvView *view)
+{
+	int index, n;
+
+	g_return_val_if_fail (EV_IS_HISTORY (view->history), FALSE);
+
+	index = ev_history_get_current_index (view->history);
+	n = ev_history_get_n_links (view->history);
+
+	if (n > 0) {
+		return index != MAX (0, index - 1);
+	} else {
+		return FALSE;
+	}
+}
+
 void
 ev_view_go_back	(EvView	*view)
 {
@@ -1139,6 +1156,23 @@ ev_view_go_back	(EvView	*view)
 	}
 }
 
+gboolean
+ev_view_can_go_forward (EvView *view)
+{
+	int index, n;
+
+	g_return_val_if_fail (EV_IS_HISTORY (view->history), FALSE);
+
+	index = ev_history_get_current_index (view->history);
+	n = ev_history_get_n_links (view->history);
+
+	if (n > 0) {
+		return 	index != MIN (n - 1, index + 1);
+	} else {
+		return FALSE;
+	}
+}
+
 void
 ev_view_go_forward (EvView *view)
 {
diff --git a/shell/ev-view.h b/shell/ev-view.h
index 0e7237d..e57371a 100644
--- a/shell/ev-view.h
+++ b/shell/ev-view.h
@@ -47,7 +47,9 @@ void		ev_view_copy		(EvView     *view);
 void		ev_view_select_all	(EvView     *view);
 
 /* Navigation */
+gboolean	ev_view_can_go_back	(EvView	    *view);
 void		ev_view_go_back		(EvView	    *view);
+gboolean	ev_view_can_go_forward	(EvView     *view);
 void		ev_view_go_forward	(EvView     *view);
 void		ev_view_go_to_link	(EvView     *view,
 					 EvLink     *link);
diff --git a/shell/ev-window.c b/shell/ev-window.c
index a1bb4db..0b8679c 100644
--- a/shell/ev-window.c
+++ b/shell/ev-window.c
@@ -178,29 +178,71 @@ static void
 update_action_sensitivity (EvWindow *ev_window)
 {
 	EvDocument *document;
-	int n_pages;
-	int page;
+	EvView *view;
+
+	gboolean can_go_back = FALSE;
+	gboolean can_go_forward = FALSE;
 
 	document = ev_window->priv->document;
 
-	if (document)
-		n_pages = ev_document_get_n_pages (document);
-	else
-		n_pages = 1;
+	view = EV_VIEW (ev_window->priv->view);
 
-	page = ev_view_get_page (EV_VIEW (ev_window->priv->view));
+	if (document) {
+		can_go_back = ev_view_can_go_back (view);
+		can_go_forward = ev_view_can_go_forward (view);
+	}
+
+	/* File menu */
+	/* "FileOpen": always sensitive */
+	set_action_sensitive (ev_window, "FileSaveAs", document!=NULL);
+	set_action_sensitive (ev_window, "FilePrint", document!=NULL);
+	/* "FileCloseWindow": always sensitive */
 
-	set_action_sensitive (ev_window, "GoFirstPage", page > 1);
-	set_action_sensitive (ev_window, "GoPageDown", page > 1);
-	set_action_sensitive (ev_window, "GoPageUp", page < n_pages);
-	set_action_sensitive (ev_window, "GoLastPage", page < n_pages);
+        /* Edit menu */
+	set_action_sensitive (ev_window, "EditCopy", document!=NULL);
+	set_action_sensitive (ev_window, "EditSelectAll", document!=NULL);
 
 	if (document)
 		set_action_sensitive (ev_window, "EditFind", EV_IS_DOCUMENT_FIND (document));
 	else
 		set_action_sensitive (ev_window, "EditFind", FALSE);
 
-	
+        /* View menu */
+	set_action_sensitive (ev_window, "ViewZoomIn", document!=NULL);
+	set_action_sensitive (ev_window, "ViewZoomOut", document!=NULL);
+	set_action_sensitive (ev_window, "ViewNormalSize", document!=NULL);
+	set_action_sensitive (ev_window, "ViewBestFit", document!=NULL);
+	set_action_sensitive (ev_window, "ViewPageWidth", document!=NULL);
+
+        /* Go menu */
+	set_action_sensitive (ev_window, "GoBack", can_go_back);
+	set_action_sensitive (ev_window, "GoForward", can_go_forward);
+	if (document) {
+		int n_pages;
+		int page;
+
+		page = ev_view_get_page (EV_VIEW (ev_window->priv->view));
+		n_pages = ev_document_get_n_pages (document);
+
+		set_action_sensitive (ev_window, "GoPageDown", page > 1);
+		set_action_sensitive (ev_window, "GoPageUp", page < n_pages);
+		set_action_sensitive (ev_window, "GoFirstPage", page > 1);
+		set_action_sensitive (ev_window, "GoLastPage", page < n_pages);
+	} else {
+		set_action_sensitive (ev_window, "GoFirstPage", FALSE);
+		set_action_sensitive (ev_window, "GoPageDown", FALSE);
+		set_action_sensitive (ev_window, "GoPageUp", FALSE);
+		set_action_sensitive (ev_window, "GoLastPage", FALSE);
+	}
+        
+	/* Help menu */
+	/* "HelpContents": always sensitive */
+	/* "HelpAbout": always sensitive */
+
+	/* Toolbar-specific actions: */
+	set_action_sensitive (ev_window, NAVIGATION_BACK_ACTION, can_go_back);
+	set_action_sensitive (ev_window, NAVIGATION_FORWARD_ACTION, can_go_forward);
+	set_action_sensitive (ev_window, PAGE_SELECTOR_ACTION, document!=NULL);
 }
 
 void