add adjustable delay for completion updates

qutebrowser/completion/completer.py

@@ -196,6 +196,8 @@ class Completer(QObject):
 
         For performance reasons we don't want to block here, instead we do this
         in the background.
+
+        We delay the update only if we've already input some text.
         """
         if (self._cmd.cursorPosition() == self._last_cursor_pos and
                 self._cmd.text() == self._last_text):
@@ -203,7 +205,7 @@ class Completer(QObject):
                                  "changes.")
         else:
             log.completion.debug("Scheduling completion update.")
-            self._timer.start()
+            self._timer.start(config.val.completion.delay if self._last_text else 0)
         self._last_cursor_pos = self._cmd.cursorPosition()
         self._last_text = self._cmd.text()
 

qutebrowser/config/configdata.yml

@@ -656,6 +656,13 @@ completion.web_history_max_items:
 
     0: no history / -1: unlimited
 
+completion.delay:
+  default: 0
+  type:
+    name: Int
+    minval: 0
+  desc: Delay in ms before updating completions after typing a character
+
 ## downloads
 
 downloads.location.directory: