Don't regenerate completion model needlessly.

If the completion model would stay the same, just keep it and update the
filter pattern rather than instantiating a new model each time the
pattern changes.

qutebrowser/completion/completer.py

@@ -39,6 +39,7 @@ class Completer(QObject):
         _last_cursor_pos: The old cursor position so we avoid double completion
                           updates.
         _last_text: The old command text so we avoid double completion updates.
+        _last_completion_func: The completion function used for the last text.
     """
 
     def __init__(self, cmd, win_id, parent=None):
@@ -52,6 +53,7 @@ class Completer(QObject):
         self._timer.timeout.connect(self._update_completion)
         self._last_cursor_pos = None
         self._last_text = None
+        self._last_completion_func = None
         self._cmd.update_completion.connect(self.schedule_completion_update)
 
     def __repr__(self):
@@ -63,7 +65,7 @@ class Completer(QObject):
         return completion.model()
 
     def _get_new_completion(self, before_cursor, under_cursor):
-        """Get a new completion.
+        """Get the completion function based on the current command text.
 
         Args:
             before_cursor: The command chunks before the cursor.
@@ -81,7 +83,7 @@ class Completer(QObject):
         if not before_cursor:
             # '|' or 'set|'
             log.completion.debug('Starting command completion')
-            return miscmodels.command()
+            return miscmodels.command
         try:
             cmd = cmdutils.cmd_dict[before_cursor[0]]
         except KeyError:
@@ -90,17 +92,11 @@ class Completer(QObject):
             return None
         argpos = len(before_cursor) - 1
         try:
-            completion = cmd.get_pos_arg_info(argpos).completion
+            func = cmd.get_pos_arg_info(argpos).completion
         except IndexError:
             log.completion.debug("No completion in position {}".format(argpos))
             return None
-        if completion is None:
-            return None
-
-        model = completion(*before_cursor[1:])
-        log.completion.debug('Starting {} completion'
-                             .format(completion.__name__))
-        return model
+        return func
 
     def _quote(self, s):
         """Quote s if it needs quoting for the commandline.
@@ -223,9 +219,24 @@ class Completer(QObject):
             before_cursor, pattern, after_cursor))
 
         pattern = pattern.strip("'\"")
-        model = self._get_new_completion(before_cursor, pattern)
-        log.completion.debug("Setting pattern to '{}'".format(pattern))
-        completion.set_model(model, pattern)
+        func = self._get_new_completion(before_cursor, pattern)
+
+        if func is None:
+            log.completion.debug('Clearing completion')
+            completion.set_model(None)
+        elif func != self._last_completion_func:
+            self._last_completion_func = func
+            args = (x for x in before_cursor[1:] if not x.startswith('-'))
+            model = func(*args)
+            log.completion.debug('Starting {} completion'
+                                 .format(func.__name__))
+            completion.set_model(model)
+            completion.set_pattern(pattern)
+        else:
+            log.completion.debug('Setting pattern {}'.format(pattern))
+            completion.set_pattern(pattern)
+
+        self._last_completion_func = None
 
     def _change_completed_part(self, newtext, before, after, immediate=False):
         """Change the part we're currently completing in the commandline.

qutebrowser/completion/completionwidget.py

@@ -261,32 +261,29 @@ class CompletionView(QTreeView):
         elif config.get('completion', 'show') == 'auto':
             self.show()
 
-    def set_model(self, model, pattern=None):
+    def set_model(self, model):
         """Switch completion to a new model.
 
         Called from on_update_completion().
 
         Args:
             model: The model to use.
-            pattern: The filter pattern to set (what the user entered).
         """
         if model is None:
             self._active = False
             self.hide()
             return
 
+        if self.model() is not None:
+            self.model().deleteLater()
+            self.selectionModel().deleteLater()
+
         model.setParent(self)
-        old_model = self.model()
-        if model is not old_model:
-            sel_model = self.selectionModel()
+        self.setModel(model)
+        self._column_widths = model.column_widths
+        self._active = True
 
-            self.setModel(model)
-            self._active = True
-
-            if sel_model is not None:
-                sel_model.deleteLater()
-            if old_model is not None:
-                old_model.deleteLater()
+        self.set_pattern('')
 
         if (config.get('completion', 'show') == 'always' and
                 model.count() > 0):
@@ -297,12 +294,11 @@ class CompletionView(QTreeView):
         for i in range(model.rowCount()):
             self.expand(model.index(i, 0))
 
-        if pattern is not None:
-            model.set_pattern(pattern)
-
-        self._column_widths = model.column_widths
+    def set_pattern(self, pattern):
+        self.model().set_pattern(pattern)
         self._resize_columns()
         self._maybe_update_geometry()
+        self.show()
 
     def _maybe_update_geometry(self):
         """Emit the update_geometry signal if the config says so."""

qutebrowser/completion/models/miscmodels.py

@@ -137,6 +137,7 @@ def bind(_key):
         _key: the key being bound.
     """
     # TODO: offer a 'Current binding' completion based on the key.
+    print(_key)
     model = completionmodel.CompletionModel(column_widths=(20, 60, 20))
     cmdlist = _get_cmd_completions(include_hidden=True, include_aliases=True)
     model.add_category(listcategory.ListCategory("Commands", cmdlist))

tests/unit/completion/test_completer.py

@@ -191,15 +191,14 @@ def test_update_completion(txt, kind, pattern, pos_args, status_command_stub,
     # this test uses | as a placeholder for the current cursor position
     _set_cmd_prompt(status_command_stub, txt)
     completer_obj.schedule_completion_update()
-    assert completion_widget_stub.set_model.call_count == 1
-    args = completion_widget_stub.set_model.call_args[0]
     if kind is None:
-        assert args[0] is None
+        assert completion_widget_stub.set_pattern.call_count == 0
     else:
-        model = args[0]
+        assert completion_widget_stub.set_model.call_count == 1
+        model = completion_widget_stub.set_model.call_args[0][0]
         assert model.kind == kind
         assert model.pos_args == pos_args
-        assert args[1] == pattern
+        completion_widget_stub.set_pattern.assert_called_once_with(pattern)
 
 
 @pytest.mark.parametrize('before, newtxt, after', [

tests/unit/completion/test_completionwidget.py

@@ -84,7 +84,8 @@ def test_set_model(completionview):
 def test_set_pattern(completionview):
     model = completionmodel.CompletionModel()
     model.set_pattern = mock.Mock()
-    completionview.set_model(model, 'foo')
+    completionview.set_model(model)
+    completionview.set_pattern('foo')
     model.set_pattern.assert_called_with('foo')