lazy sessions

qutebrowser/browser/qutescheme.py

@@ -424,6 +424,13 @@ def qute_settings(url):
                         confget=config.instance.get_str)
     return 'text/html', html
 
+@add_handler('back')
+def qute_back(url):
+    """Handler for qute://back. Simple page to free ram / lazy load a site,
+    goes back on focusing the tab."""
+
+    html = jinja.render('back.html', title='Suspended')
+    return 'text/html', html
 
 @add_handler('configdiff')
 def qute_configdiff(url):

qutebrowser/config/configdata.yml

@@ -88,6 +88,14 @@ session_default_name:
 
     If this is set to null, the session which was last loaded is saved.
 
+session_lazy_restore:
+  type:
+    name: Bool
+    none_ok: true
+  default: false
+  desc: >-
+    Load a restored tab as soon as it takes focus.
+
 backend:
   type:
     name: String

qutebrowser/misc/sessions.py

@@ -347,7 +347,9 @@ class SessionManager(QObject):
             if 'pinned' in histentry:
                 new_tab.data.pinned = histentry['pinned']
 
-            active = histentry.get('active', False)
+            active = (histentry.get('active', False) and
+                     (not config.val.session_lazy_restore or
+                      histentry['url'].startswith('qute://')))
             url = QUrl.fromEncoded(histentry['url'].encode('ascii'))
             if 'original-url' in histentry:
                 orig_url = QUrl.fromEncoded(
@@ -360,6 +362,19 @@ class SessionManager(QObject):
             entries.append(entry)
             if active:
                 new_tab.title_changed.emit(histentry['title'])
+
+        if config.val.session_lazy_restore and data['history']:
+            last = data['history'][-1]
+            title = last['title']
+            url = 'qute://back#' + title
+            active = last.get('active', False)
+
+            if not last['url'].startswith('qute://'):
+                entries.append(TabHistoryItem(url=QUrl.fromEncoded(url.encode('ascii')),
+                                              title=title, active=active, user_data={}))
+                if active:
+                    new_tab.title_changed.emit(title)
+
         try:
             new_tab.history.load_items(entries)
         except ValueError as e: