grep: allow moving between query and result using the arrow keys

The query input field already knew to focus the results when pressing
either enter, return, or the down-arrow key.  Teach the results field to
focus the input field when the up-arrow is pressed.

This makes the behavior consistent with the commit message editor.

Signed-off-by: David Aguilar <davvid@gmail.com>

cola/widgets/grep.py

@@ -107,6 +107,8 @@ def __init__(self, parent):
         self.connect(self.input_txt, SIGNAL('textChanged(QString)'),
                      self.input_txt_changed)
 
+        self.connect(self.result_txt, SIGNAL('leave()'),
+                     lambda: self.input_txt.setFocus())
 
         qtutils.add_action(self.input_txt, 'FocusResults',
                            lambda: self.result_txt.setFocus(),
@@ -231,6 +233,18 @@ def paintEvent(self, event):
             painter = QtGui.QPainter(self.viewport())
             painter.fillRect(rect, Qt.SolidPattern)
 
+    def keyPressEvent(self, event):
+        if event.key() == Qt.Key_Up:
+            cursor = self.textCursor()
+            position = cursor.position()
+            if position == 0 and not cursor.hasSelection():
+                # The cursor is at the beginning of the line.
+                # If we have selection then simply reset the cursor.
+                # Otherwise, emit a signal so that the parent can
+                # change focus.
+                self.emit(SIGNAL('leave()'))
+        return HintedTextView.keyPressEvent(self, event)
+
 
 def goto_grep(line):
     """Called when Search -> Grep's right-click 'goto' action."""