[evince] ev-history: Add methods to freeze/thaw history

[Carlos Garcia Campos <carlosgc src gnome org>]

commit e9b279c23ec248e92ee0070890741f86756ca279
Author: Carlos Garcia Campos <carlosgc gnome org>
Date:   Sat Apr 20 17:39:44 2013 +0200

    ev-history: Add methods to freeze/thaw history

 shell/ev-history.c | 40 ++++++++++++++++++++++++++++++++++------
 shell/ev-history.h |  3 +++
 2 files changed, 37 insertions(+), 6 deletions(-)
---
diff --git a/shell/ev-history.c b/shell/ev-history.c
index 0f3ee2d..21788d1 100644
--- a/shell/ev-history.c
+++ b/shell/ev-history.c
@@ -41,6 +41,8 @@ struct _EvHistoryPrivate {
         EvDocumentModel *model;
         gulong           page_changed_handler_id;
         gboolean         activating_current_link;
+
+        guint            frozen;
 };
 
 G_DEFINE_TYPE (EvHistory, ev_history, G_TYPE_OBJECT)
@@ -106,6 +108,12 @@ ev_history_init (EvHistory *history)
        history->priv = G_TYPE_INSTANCE_GET_PRIVATE (history, EV_TYPE_HISTORY, EvHistoryPrivate);
 }
 
+static gboolean
+ev_history_is_frozen (EvHistory *history)
+{
+        return history->priv->frozen > 0;
+}
+
 void
 ev_history_add_link (EvHistory *history,
                      EvLink    *link)
@@ -113,7 +121,7 @@ ev_history_add_link (EvHistory *history,
        g_return_if_fail (EV_IS_HISTORY (history));
        g_return_if_fail (EV_IS_LINK (link));
 
-        if (history->priv->activating_current_link)
+        if (ev_history_is_frozen (history) || history->priv->activating_current_link)
                 return;
 
         if (ev_history_go_to_link (history, link))
@@ -151,7 +159,7 @@ ev_history_can_go_back (EvHistory *history)
 {
         g_return_val_if_fail (EV_IS_HISTORY (history), FALSE);
 
-        return history->priv->back_list != NULL;
+        return history->priv->back_list != NULL && !ev_history_is_frozen (history);
 }
 
 void
@@ -159,7 +167,7 @@ ev_history_go_back (EvHistory *history)
 {
         g_return_if_fail (EV_IS_HISTORY (history));
 
-        if (!history->priv->current || !history->priv->back_list)
+        if (!history->priv->current || !history->priv->back_list || ev_history_is_frozen (history))
                 return;
 
         history->priv->forward_list = g_list_prepend (history->priv->forward_list,
@@ -176,7 +184,7 @@ ev_history_can_go_forward (EvHistory *history)
 {
         g_return_val_if_fail (EV_IS_HISTORY (history), FALSE);
 
-        return history->priv->forward_list != NULL;
+        return history->priv->forward_list != NULL && !ev_history_is_frozen (history);
 }
 
 void
@@ -184,7 +192,7 @@ ev_history_go_forward (EvHistory *history)
 {
         g_return_if_fail (EV_IS_HISTORY (history));
 
-        if (!history->priv->current || !history->priv->forward_list)
+        if (!history->priv->current || !history->priv->forward_list || ev_history_is_frozen (history))
                 return;
 
         history->priv->back_list = g_list_prepend (history->priv->back_list,
@@ -215,7 +223,7 @@ ev_history_go_to_link (EvHistory *history,
         g_return_val_if_fail (EV_IS_HISTORY (history), FALSE);
         g_return_val_if_fail (EV_IS_LINK (link), FALSE);
 
-        if (!history->priv->current || (!history->priv->back_list && !history->priv->forward_list))
+        if (!history->priv->current || (!history->priv->back_list && !history->priv->forward_list) || 
ev_history_is_frozen (history))
                 return FALSE;
 
         l = g_list_find_custom (history->priv->back_list, link, (GCompareFunc)compare_link);
@@ -277,6 +285,23 @@ ev_history_get_forward_list (EvHistory *history)
         return history->priv->forward_list;
 }
 
+void
+ev_history_freeze (EvHistory *history)
+{
+        g_return_if_fail (EV_IS_HISTORY (history));
+
+        history->priv->frozen++;
+}
+
+void
+ev_history_thaw (EvHistory *history)
+{
+        g_return_if_fail (EV_IS_HISTORY (history));
+        g_return_if_fail (history->priv->frozen > 0);
+
+        history->priv->frozen--;
+}
+
 static gint
 ev_history_get_current_page (EvHistory *history)
 {
@@ -331,6 +356,9 @@ ev_history_add_link_for_page (EvHistory *history,
         gchar        *page_label;
         gchar        *title;
 
+        if (ev_history_is_frozen (history))
+                return;
+
         if (ev_history_get_current_page (history) == page)
                 return;
 
diff --git a/shell/ev-history.h b/shell/ev-history.h
index 02604c7..41f55b7 100644
--- a/shell/ev-history.h
+++ b/shell/ev-history.h
@@ -67,6 +67,9 @@ gboolean        ev_history_go_to_link       (EvHistory       *history,
 GList          *ev_history_get_back_list    (EvHistory       *history);
 GList          *ev_history_get_forward_list (EvHistory       *history);
 
+void            ev_history_freeze           (EvHistory       *history);
+void            ev_history_thaw             (EvHistory       *history);
+
 G_END_DECLS
 
 #endif