Temporarily save edits when moving through history in Qt console.

IPython/frontend/qt/console/history_console_widget.py

@@ -1,173 +1,194
 # System library imports
 from IPython.external.qt import QtGui
 
 # Local imports
 from console_widget import ConsoleWidget
 
 
 class HistoryConsoleWidget(ConsoleWidget):
     """ A ConsoleWidget that keeps a history of the commands that have been
         executed and provides a readline-esque interface to this history.
     """
     
     #---------------------------------------------------------------------------
     # 'object' interface
     #---------------------------------------------------------------------------
 
     def __init__(self, *args, **kw):
         super(HistoryConsoleWidget, self).__init__(*args, **kw)
 
         # HistoryConsoleWidget protected variables.
         self._history = []
+        self._history_edits = {}
         self._history_index = 0
         self._history_prefix = ''
 
     #---------------------------------------------------------------------------
     # 'ConsoleWidget' public interface
     #---------------------------------------------------------------------------
 
     def execute(self, source=None, hidden=False, interactive=False):
         """ Reimplemented to the store history.
         """
         if not hidden:
             history = self.input_buffer if source is None else source
 
         executed = super(HistoryConsoleWidget, self).execute(
             source, hidden, interactive)
 
         if executed and not hidden:
             # Save the command unless it was an empty string or was identical 
             # to the previous command.
             history = history.rstrip()
             if history and (not self._history or self._history[-1] != history):
                 self._history.append(history)
 
+            # Emulate readline: reset all history edits.
+            self._history_edits = {}
+
             # Move the history index to the most recent item.
             self._history_index = len(self._history)
 
         return executed
 
     #---------------------------------------------------------------------------
     # 'ConsoleWidget' abstract interface
     #---------------------------------------------------------------------------
 
     def _up_pressed(self):
         """ Called when the up key is pressed. Returns whether to continue
             processing the event.
         """
         prompt_cursor = self._get_prompt_cursor()
         if self._get_cursor().blockNumber() == prompt_cursor.blockNumber():
 
             # Set a search prefix based on the cursor position.
             col = self._get_input_buffer_cursor_column()
             input_buffer = self.input_buffer
             if self._history_index == len(self._history) or \
                     (self._history_prefix and col != len(self._history_prefix)):
                 self._history_index = len(self._history)
                 self._history_prefix = input_buffer[:col]
 
             # Perform the search.
             self.history_previous(self._history_prefix)
 
             # Go to the first line of the prompt for seemless history scrolling.
             # Emulate readline: keep the cursor position fixed for a prefix
             # search.
             cursor = self._get_prompt_cursor()
             if self._history_prefix:
                 cursor.movePosition(QtGui.QTextCursor.Right, 
                                     n=len(self._history_prefix))
             else:
                 cursor.movePosition(QtGui.QTextCursor.EndOfLine)
             self._set_cursor(cursor)
 
             return False
 
         return True
 
     def _down_pressed(self):
         """ Called when the down key is pressed. Returns whether to continue
             processing the event.
         """
         end_cursor = self._get_end_cursor()
         if self._get_cursor().blockNumber() == end_cursor.blockNumber():
 
             # Perform the search.
             self.history_next(self._history_prefix)
 
             # Emulate readline: keep the cursor position fixed for a prefix
             # search. (We don't need to move the cursor to the end of the buffer
             # in the other case because this happens automatically when the
             # input buffer is set.)
             if self._history_prefix:
                 cursor = self._get_prompt_cursor()
                 cursor.movePosition(QtGui.QTextCursor.Right, 
                                     n=len(self._history_prefix))
                 self._set_cursor(cursor)
 
             return False
 
         return True
 
     #---------------------------------------------------------------------------
     # 'HistoryConsoleWidget' public interface
     #---------------------------------------------------------------------------
 
     def history_previous(self, prefix=''):
-        """ If possible, set the input buffer to a previous item in the history.
+        """ If possible, set the input buffer to a previous history item.
 
         Parameters:
         -----------
         prefix : str, optional
             If specified, search for an item with this prefix.
         """
         index = self._history_index
         while index > 0:
             index -= 1
-            history = self._history[index]
+            history = self._get_edited_history(index)
             if history.startswith(prefix):
                 break
         else:
             history = None
         
         if history is not None:
+            self._set_edited_input_buffer(history)
             self._history_index = index
-            self.input_buffer = history
 
     def history_next(self, prefix=''):
-        """ Set the input buffer to a subsequent item in the history, or to the
-        original search prefix if there is no such item.
+        """ If possible, set the input buffer to a subsequent history item.
 
         Parameters:
         -----------
         prefix : str, optional
             If specified, search for an item with this prefix.
         """
-        while self._history_index < len(self._history) - 1:
-            self._history_index += 1
-            history = self._history[self._history_index]
+        index = self._history_index
+        while self._history_index < len(self._history):
+            index += 1
+            history = self._get_edited_history(index)
             if history.startswith(prefix):
                 break
         else:
-            self._history_index = len(self._history)
-            history = prefix
-        self.input_buffer = history
+            history = None
+
+        if history is not None:
+            self._set_edited_input_buffer(history)
+            self._history_index = index
 
     def history_tail(self, n=10):
         """ Get the local history list.
 
-        Parameters
-        ----------
+        Parameters:
+        -----------
         n : int
             The (maximum) number of history items to get.
         """
         return self._history[-n:]
         
     #---------------------------------------------------------------------------
     # 'HistoryConsoleWidget' protected interface
     #---------------------------------------------------------------------------
 
+    def _get_edited_history(self, index):
+        """ Retrieves a history item, possibly with temporary edits.
+        """
+        if index in self._history_edits:
+            return self._history_edits[index]
+        return self._history[index]
+
+    def _set_edited_input_buffer(self, source):
+        """ Sets the input buffer to 'source', saving the current input buffer
+            as a temporary history edit.
+        """
+        self._history_edits[self._history_index] = self.input_buffer
+        self.input_buffer = source
+
     def _set_history(self, history):
         """ Replace the current history with a sequence of history items.
         """
         self._history = list(history)
+        self._history_edits = {}
         self._history_index = len(self._history)