Tabs->show option.

Issue #771
Implemted common option for tab bar show strategy.
Options: always, never, multiple, switching.

qutebrowser/config/configdata.py

@@ -479,13 +479,13 @@ def data(readonly=False):
              SettingValue(typ.LastClose(), 'ignore'),
              "Behavior when the last tab is closed."),
 
-            ('hide-auto',
+            ('show',
-             SettingValue(typ.Bool(), 'false'),
+             SettingValue(typ.TabBarShow(), 'always'),
-             "Hide the tab bar if only one tab is open."),
+             "The tab bar showing strategy."),
 
-            ('hide-always',
+            ('show-switching-delay',
-             SettingValue(typ.Bool(), 'false'),
+             SettingValue(typ.Int(), '800'),
-             "Always hide the tab bar."),
+             "Time to show tab bar before hide it when tabs->show is switching."),
 
             ('wrap',
              SettingValue(typ.Bool(), 'true'),

qutebrowser/config/configtypes.py

@@ -1566,3 +1566,14 @@ class UserAgent(BaseType):
              "curl 7.40.0")
         ]
         return out
+
+class TabBarShow(BaseType):
+
+    """How to format the question when downloading."""
+
+    valid_values = ValidValues(('always', "Always show the tab bar."),
+                               ('never', "Always hide the tab bar."),
+                               ('multiple', "Hide the tab bar if only one tab is open."),
+                               ('switching', "Show the tab bar only when current tab changed."))
+
+

qutebrowser/mainwindow/tabwidget.py

@@ -194,6 +194,7 @@ class TabWidget(QTabWidget):
     @pyqtSlot(int)
     def emit_tab_index_changed(self, index):
         """Emit the tab_index_changed signal if the current tab changed."""
+        self.tabBar().on_change()
         self.tab_index_changed.emit(index, self.count())
 
 
@@ -220,32 +221,48 @@ class TabBar(QTabBar):
         config_obj = objreg.get('config')
         config_obj.changed.connect(self.set_font)
         self.vertical = False
+        self.autoHideTimer = None
         self.setAutoFillBackground(True)
         self.set_colors()
         config_obj.changed.connect(self.set_colors)
         QTimer.singleShot(0, self._tabhide)
-        config_obj.changed.connect(self.autohide)
-        config_obj.changed.connect(self.alwayshide)
         config_obj.changed.connect(self.on_tab_colors_changed)
+        config_obj.changed.connect(self.showswitchingdelay)
+        config_obj.changed.connect(self.tabs_show)
 
     def __repr__(self):
         return utils.get_repr(self, count=self.count())
 
-    @config.change_filter('tabs', 'hide-auto')
+    @config.change_filter('tabs', 'show')
-    def autohide(self):
+    def tabs_show(self):
-        """Hide tab bar if needed when tabs->hide-auto got changed."""
+        """Hide or show tab bar if needed when tabs->show got changed."""
         self._tabhide()
 
-    @config.change_filter('tabs', 'hide-always')
+    @config.change_filter('tabs', 'show-switching-delay')
-    def alwayshide(self):
+    def showswitchingdelay(self):
-        """Hide tab bar if needed when tabs->hide-always got changed."""
+        """Reset auto hide timer when tabs->show-switching-delay got changed."""
-        self._tabhide()
+        self.autoHideTimer = None
+
+    def on_change(self):
+        """Show tab bar when current tab got changed."""
+        show = config.get('tabs', 'show')
+        show_switching_delay = config.get('tabs', 'show-switching-delay')
+        if show == 'switching':
+            self.show()
+            if not self.autoHideTimer:
+                self.autoHideTimer = QTimer()
+                self.autoHideTimer.setInterval(show_switching_delay)
+                self.autoHideTimer.setSingleShot(True)
+                self.autoHideTimer.timeout.connect(self._tabhide)
+            self.autoHideTimer.start()
 
     def _tabhide(self):
         """Hide the tab bar if needed."""
-        hide_auto = config.get('tabs', 'hide-auto')
+        show = config.get('tabs', 'show')
-        hide_always = config.get('tabs', 'hide-always')
+        showNever = show == 'never'
-        if hide_always or (hide_auto and self.count() == 1):
+        showSwitching = show == 'switching'
+        showMultiple = show == 'multiple'
+        if showNever or (showMultiple and self.count() == 1) or showSwitching:
             self.hide()
         else:
             self.show()