Implement utils.is_special_key.

The check `key.startswith('<') and key.endswith('>') is repeated many
times in code to check for a special key. Replace all these with a call
to the same function.

qutebrowser/completion/models/miscmodels.py

@@ -24,7 +24,7 @@ from PyQt5.QtCore import Qt, QTimer, pyqtSlot
 
 from qutebrowser.browser import webview
 from qutebrowser.config import config, configdata
-from qutebrowser.utils import objreg, log, qtutils
+from qutebrowser.utils import objreg, log, qtutils, utils
 from qutebrowser.commands import cmdutils
 from qutebrowser.completion.models import base
 
@@ -57,7 +57,7 @@ class CommandCompletionModel(base.BaseCompletionModel):
         cmd_to_keys = defaultdict(list)
         for key, cmd in keyconf.get_bindings_for('normal').items():
             # put special bindings last
-            if key.startswith('<') and key.endswith('>'):
+            if utils.is_special_key(key):
                 cmd_to_keys[cmd].append(key)
             else:
                 cmd_to_keys[cmd].insert(0, key)

qutebrowser/keyinput/basekeyparser.py

@@ -335,7 +335,7 @@ class BaseKeyParser(QObject):
 
     def _parse_key_command(self, modename, key, cmd):
         """Parse the keys and their command and store them in the object."""
-        if key.startswith('<') and key.endswith('>'):
+        if utils.is_special_key(key):
             keystr = utils.normalize_keystr(key[1:-1])
             self.special_bindings[keystr] = cmd
         elif self._supports_chains:

qutebrowser/misc/keyhintwidget.py

@@ -95,10 +95,9 @@ class KeyHintView(QLabel):
             return
 
         keyconf = objreg.get('key-config')
-        is_special = lambda k: k.startswith('<') and k.endswith('>')
-        bindings = [(key, cmd) for (key, cmd)
+        bindings = [(k, v) for (k, v)
                     in keyconf.get_bindings_for(modename).items()
-                    if key.startswith(prefix) and not is_special(key)]
+                    if k.startswith(prefix) and not utils.is_special_key(k)]
 
         if not bindings:
             return

qutebrowser/utils/utils.py

@@ -440,9 +440,14 @@ class KeyParseError(Exception):
         super().__init__("Could not parse {!r}: {}".format(keystr, error))
 
 
+def is_special_key(keystr):
+    """True if keystr is a 'special' keystring (e.g. <ctrl-x> or <space>)."""
+    return keystr.startswith('<') and keystr.endswith('>')
+
+
 def _parse_single_key(keystr):
     """Convert a single key string to a (Qt.Key, Qt.Modifiers, text) tuple."""
-    if keystr.startswith('<') and keystr.endswith('>'):
+    if is_special_key(keystr):
         # Special key
         keystr = keystr[1:-1]
     elif len(keystr) == 1:
@@ -489,7 +494,7 @@ def _parse_single_key(keystr):
 
 def parse_keystring(keystr):
     """Parse a keystring like <Ctrl-x> or xyz and return a KeyInfo list."""
-    if keystr.startswith('<') and keystr.endswith('>'):
+    if is_special_key(keystr):
         return [_parse_single_key(keystr)]
     else:
         return [_parse_single_key(char) for char in keystr]

tests/unit/utils/test_utils.py

@@ -984,3 +984,19 @@ class TestGetSetClipboard:
     def test_supports_selection(self, clipboard_mock, selection):
         clipboard_mock.supportsSelection.return_value = selection
         assert utils.supports_selection() == selection
+
+
+@pytest.mark.parametrize('keystr, expected', [
+    ('<Control-x>', True),
+    ('<Meta-x>', True),
+    ('<Ctrl-Alt-y>', True),
+    ('x', False),
+    ('X', False),
+    ('<Escape>', True),
+    ('foobar', False),
+    ('foo>', False),
+    ('<foo', False),
+    ('<<', False),
+])
+def test_is_special_key(keystr, expected):
+    assert utils.is_special_key(keystr) == expected