[WIP] PR: Create widget to manage list history

qtconsole/history_console_widget.py

@@ -1,10 +1,28 @@
 # Copyright (c) Jupyter Development Team.
 # Distributed under the terms of the Modified BSD License.
+import os
+import os.path
 
-from qtpy import QtGui
+from qtpy import QtCore, QtGui, QtWidgets
 
 from traitlets import Bool
 from .console_widget import ConsoleWidget
+from .completion_widget import CompletionWidget
+
+
+class HistoryListWidget(CompletionWidget):
+    """ A widget for GUI list history.
+    """
+    complete_current = QtCore.Signal(str)
+
+    def _complete_current(self):
+        """ Perform the completion with the currently selected item.
+        """
+        text = self.currentItem().data(QtCore.Qt.UserRole)
+        self.parent()._store_edits()
+        self.parent().input_buffer = text
+        self.complete_current.emit(text)
+        self.hide()
 
 
 class HistoryConsoleWidget(ConsoleWidget):
@@ -31,6 +49,15 @@ def __init__(self, *args, **kw):
         self._history_edits = {}
         self._history_index = 0
         self._history_prefix = ''
+        self.droplist_history = QtWidgets.QAction("Show related history execution entries",
+                self,
+                shortcut="Ctrl+Shift+R",
+                shortcutContext=QtCore.Qt.WidgetWithChildrenShortcut,
+                triggered=self._show_history_droplist
+        )
+        self.addAction(self.droplist_history)
+        self._history_list_widget = HistoryListWidget(self, self.gui_completion_height)
+        self._history_list_widget.complete_current.connect(self.change_input_buffer)
 
     #---------------------------------------------------------------------------
     # 'ConsoleWidget' public interface
@@ -142,6 +169,70 @@ def _down_pressed(self, shift_modifier):
 
         return True
 
+    def _show_history_droplist(self):
+        # Perform the search.
+        prompt_cursor = self._get_prompt_cursor()
+        if self._get_cursor().blockNumber() == prompt_cursor.blockNumber():
+
+            # Set a search prefix based on the cursor position.
+            pos = self._get_input_buffer_cursor_pos()
+            input_buffer = self.input_buffer
+            # use the *shortest* of the cursor column and the history prefix
+            # to determine if the prefix has changed
+            n = min(pos, len(self._history_prefix))
+
+            # prefix changed, restart search from the beginning
+            if self._history_prefix[:n] != input_buffer[:n]:
+                self._history_index = len(self._history)
+
+            # the only time we shouldn't set the history prefix
+            # to the line up to the cursor is if we are already
+            # in a simple scroll (no prefix),
+            # and the cursor is at the end of the first line
+
+            # check if we are at the end of the first line
+            c = self._get_cursor()
+            current_pos = c.position()
+            c.movePosition(QtGui.QTextCursor.EndOfBlock)
+            at_eol = c.position() == current_pos
+
+            if (
+                self._history_index == len(self._history)
+                or not (self._history_prefix == "" and at_eol)
+                or not (
+                    self._get_edited_history(self._history_index)[:pos]
+                    == input_buffer[:pos]
+                )
+            ):
+                self._history_prefix = input_buffer[:pos]
+        items = self._history
+        items.reverse()
+        if self._history_prefix:
+            items = [
+                item
+                for item in items
+                if item.startswith(self._history_prefix)
+            ]
+
+        cursor = self._get_cursor()
+        pos = len(self._history_prefix)
+        cursor_pos = self._get_input_buffer_cursor_pos()
+        cursor.movePosition(QtGui.QTextCursor.Left, n=(cursor_pos - pos))
+        # This line actually applies the move to control's cursor
+        self._control.setTextCursor(cursor)
+
+        self._history_list_widget.cancel_completion()
+        if len(items) == 1:
+            self._history_list_widget.show_items(
+                cursor, items
+            )
+        elif len(items) > 1:
+            current_pos = self._control.textCursor().position()
+            prefix = os.path.commonprefix(items)
+            self._history_list_widget.show_items(
+                cursor, items, prefix_length=len(prefix)
+            )
+
     #---------------------------------------------------------------------------
     # 'HistoryConsoleWidget' public interface
     #---------------------------------------------------------------------------
@@ -173,9 +264,7 @@ def history_previous(self, substring='', as_prefix=True):
                 break
 
         if replace:
-            self._store_edits()
-            self._history_index = index
-            self.input_buffer = history
+            self.change_input_buffer(history, index=index)
 
         return replace
 
@@ -206,9 +295,7 @@ def history_next(self, substring='', as_prefix=True):
                 break
 
         if replace:
-            self._store_edits()
-            self._history_index = index
-            self.input_buffer = history
+            self.change_input_buffer(history, index=index)
 
         return replace
 
@@ -222,6 +309,21 @@ def history_tail(self, n=10):
         """
         return self._history[-n:]
 
+    @QtCore.Slot(str)
+    def change_input_buffer(self, buffer, index=0):
+        """Change input_buffer value while storing edits and updating history index.
+
+        Parameters
+        ----------
+        buffer : str
+            New value for the inpur buffer.
+        index : int, optional
+            History index to set. The default is 0.
+        """
+        self._store_edits()
+        self._history_index = index
+        self.input_buffer = buffer
+
     #---------------------------------------------------------------------------
     # 'HistoryConsoleWidget' protected interface
     #---------------------------------------------------------------------------