Only load pages when their tab is switched to upon session restore

Firefox has led the way implementing this behaviour to improve the experience
of restoring a session with lots of tabs. By delaying the loading of pages to
when the user shows interest in them, the time it takes for the browser to
become usable is diminished, and less pages are loaded in parallel, which
improves load time for the first pages the user sees.

It also has the advante of displaying less HTTP Basic Auth dialogs, when the
user has many tabs pointed to the same server.

https://bugzilla.gnome.org/show_bug.cgi?id=675302

4 files changed, 29 insertions, 10 deletions

diff --git a/src/ephy-notebook.c b/src/ephy-notebook.c
index 2349af8f9..f9a9007c6 100644
--- a/src/ephy-notebook.c
+++ b/src/ephy-notebook.c
@@ -467,12 +467,14 @@ static void
 sync_load_status (EphyWebView *view, GParamSpec *pspec, GtkWidget *proxy)
 {
 	GtkWidget *spinner, *icon;
+	EphyEmbed *embed;
 
 	spinner = GTK_WIDGET (g_object_get_data (G_OBJECT (proxy), "spinner"));
 	icon = GTK_WIDGET (g_object_get_data (G_OBJECT (proxy), "icon"));
 	g_return_if_fail (spinner != NULL && icon != NULL);
 
-	if (ephy_web_view_is_loading (view))
+	embed = EPHY_GET_EMBED_FROM_EPHY_WEB_VIEW (view);
+	if (ephy_web_view_is_loading (view) && !ephy_embed_has_load_pending (embed))
 	{
 		gtk_widget_hide (icon);
 		gtk_widget_show (spinner);
diff --git a/src/ephy-session.c b/src/ephy-session.c
index 47dfe08bd..82ecf4149 100644
--- a/src/ephy-session.c
+++ b/src/ephy-session.c
@@ -631,7 +631,7 @@ session_tab_new (EphyEmbed *embed)
 	}
 
 	session_tab->title = g_strdup (ephy_web_view_get_title (web_view));
-	session_tab->loading = ephy_web_view_is_loading (web_view);
+	session_tab->loading = ephy_web_view_is_loading (web_view) && !ephy_embed_has_load_pending (embed);
 
 	return session_tab;
 }
@@ -1102,11 +1102,19 @@ session_parse_embed (SessionParserContext *context,
 	 */
 	if (!was_loading || is_blank_page)
 	{
-		ephy_shell_new_tab (ephy_shell_get_default (),
-				    context->window, NULL, url,
-				    EPHY_NEW_TAB_IN_EXISTING_WINDOW |
-				    EPHY_NEW_TAB_OPEN_PAGE |
-				    EPHY_NEW_TAB_APPEND_LAST);
+		EphyNewTabFlags flags;
+		EphyEmbed *embed;
+		EphyWebView *web_view;
+
+		flags = EPHY_NEW_TAB_IN_EXISTING_WINDOW;
+		flags |= EPHY_NEW_TAB_APPEND_LAST;
+	        flags |= EPHY_NEW_TAB_DELAYED_OPEN_PAGE;
+
+		embed = ephy_shell_new_tab (ephy_shell_get_default (),
+					    context->window, NULL, url, flags);
+
+		web_view = ephy_embed_get_web_view (embed);
+		ephy_web_view_set_placeholder (web_view, url, title);
 	}
 	else if (was_loading && url != NULL)
 	{
@@ -1150,6 +1158,7 @@ session_end_element (GMarkupParseContext  *ctx,
 	if (strcmp (element_name, "window") == 0)
 	{
 		GtkWidget *notebook;
+		EphyEmbedShell *shell = ephy_embed_shell_get_default ();
 
 		notebook = ephy_window_get_notebook (context->window);
 		gtk_notebook_set_current_page (GTK_NOTEBOOK (notebook), context->active_tab);
@@ -1163,6 +1172,8 @@ session_end_element (GMarkupParseContext  *ctx,
 			gtk_widget_show (GTK_WIDGET (context->window));
 		}
 
+		ephy_embed_shell_restored_window (shell);
+
 		context->window = NULL;
 		context->active_tab = 0;
 		context->is_first_window = FALSE;
diff --git a/src/ephy-shell.c b/src/ephy-shell.c
index 7fd01d7de..ebdd48fd0 100644
--- a/src/ephy-shell.c
+++ b/src/ephy-shell.c
@@ -730,6 +730,7 @@ ephy_shell_new_tab_full (EphyShell *shell,
   gboolean fullscreen_lockdown = FALSE;
   gboolean in_new_window = TRUE;
   gboolean open_page = FALSE;
+  gboolean delayed_open_page = FALSE;
   gboolean jump_to = FALSE;
   gboolean active_is_blank = FALSE;
   gboolean copy_history = TRUE;
@@ -748,6 +749,7 @@ ephy_shell_new_tab_full (EphyShell *shell,
   embed_shell = EPHY_EMBED_SHELL (shell);
 
   if (flags & EPHY_NEW_TAB_OPEN_PAGE) open_page = TRUE;
+  if (flags & EPHY_NEW_TAB_DELAYED_OPEN_PAGE) delayed_open_page = TRUE;
   if (flags & EPHY_NEW_TAB_IN_NEW_WINDOW) in_new_window = TRUE;
   if (flags & EPHY_NEW_TAB_IN_EXISTING_WINDOW) in_new_window = FALSE;
   if (flags & EPHY_NEW_TAB_DONT_COPY_HISTORY) copy_history = FALSE;
@@ -756,7 +758,7 @@ ephy_shell_new_tab_full (EphyShell *shell,
   fullscreen_lockdown = g_settings_get_boolean (EPHY_SETTINGS_LOCKDOWN,
                                                 EPHY_PREFS_LOCKDOWN_FULLSCREEN);
   in_new_window = in_new_window && !fullscreen_lockdown;
-  g_return_val_if_fail (open_page == (gboolean)(request != NULL), NULL);
+  g_return_val_if_fail ((open_page || delayed_open_page) == (gboolean)(request != NULL), NULL);
 
   LOG ("Opening new tab parent-window %p parent-embed %p in-new-window:%s jump-to:%s",
        parent_window, previous_embed, in_new_window ? "t" : "f", jump_to ? "t" : "f");
@@ -822,7 +824,7 @@ ephy_shell_new_tab_full (EphyShell *shell,
     ephy_window_activate_location (window);
     ephy_web_view_load_homepage (view);
     is_empty = TRUE;
-  } else if (flags & EPHY_NEW_TAB_OPEN_PAGE) {
+  } else if (open_page) {
     ephy_web_view_load_request (ephy_embed_get_web_view (embed),
                                 request);
 
@@ -831,7 +833,8 @@ ephy_shell_new_tab_full (EphyShell *shell,
 #else
     is_empty = ephy_embed_utils_url_is_empty (webkit_network_request_get_uri (request));
 #endif
-  }
+  } else if (delayed_open_page)
+      ephy_embed_set_delayed_load_request (embed, request);
 
   /* Make sure the initial focus is somewhere sensible and not, for
    * example, on the reload button.
diff --git a/src/ephy-shell.h b/src/ephy-shell.h
index f65083a7e..7b250fe26 100644
--- a/src/ephy-shell.h
+++ b/src/ephy-shell.h
@@ -59,6 +59,8 @@ typedef struct _EphyShellPrivate  EphyShellPrivate;
  * @EPHY_NEW_TAB_HOME_PAGE: loads the home page in the new tab.
  * @EPHY_NEW_TAB_NEW_PAGE: legacy synonym for @EPHY_NEW_TAB_HOME_PAGE.
  * @EPHY_NEW_TAB_OPEN_PAGE: opens the provided network-request.
+ * @EPHY_NEW_TAB_DELAYED_OPEN_PAGE: store the provided network-request
+ *        so that it will be opened when the tab is switched to.
  * @EPHY_NEW_TAB_FULLSCREEN_MODE: calls gtk_window_fullscreen on the
  *        parent window of the new tab.
  * @EPHY_NEW_TAB_DONT_SHOW_WINDOW: do not show the window where the new
@@ -85,6 +87,7 @@ typedef enum {
   EPHY_NEW_TAB_HOME_PAGE    = 1 << 0,
   EPHY_NEW_TAB_NEW_PAGE   = 1 << 1,
   EPHY_NEW_TAB_OPEN_PAGE    = 1 << 2,
+  EPHY_NEW_TAB_DELAYED_OPEN_PAGE    = 1 << 3,
 
   /* Page mode */
   EPHY_NEW_TAB_FULLSCREEN_MODE  = 1 << 4,