add ydb deps

1 files changed, 1415 insertions, 0 deletions

diff --git a/contrib/python/prompt-toolkit/py2/prompt_toolkit/buffer.py b/contrib/python/prompt-toolkit/py2/prompt_toolkit/buffer.py
new file mode 100644
index 0000000000..f5df289827
--- /dev/null
+++ b/contrib/python/prompt-toolkit/py2/prompt_toolkit/buffer.py
@@ -0,0 +1,1415 @@
+"""
+Data structures for the Buffer.
+It holds the text, cursor position, history, etc...
+"""
+from __future__ import unicode_literals
+
+from .auto_suggest import AutoSuggest
+from .clipboard import ClipboardData
+from .completion import Completer, Completion, CompleteEvent
+from .document import Document
+from .enums import IncrementalSearchDirection
+from .filters import to_simple_filter
+from .history import History, InMemoryHistory
+from .search_state import SearchState
+from .selection import SelectionType, SelectionState, PasteMode
+from .utils import Event
+from .cache import FastDictCache
+from .validation import ValidationError
+
+from six.moves import range
+
+import os
+import re
+import shlex
+import six
+import subprocess
+import tempfile
+
+__all__ = (
+    'EditReadOnlyBuffer',
+    'AcceptAction',
+    'Buffer',
+    'indent',
+    'unindent',
+    'reshape_text',
+)
+
+
+class EditReadOnlyBuffer(Exception):
+    " Attempt editing of read-only :class:`.Buffer`. "
+
+
+class AcceptAction(object):
+    """
+    What to do when the input is accepted by the user.
+    (When Enter was pressed in the command line.)
+
+    :param handler: (optional) A callable which takes a
+        :class:`~prompt_toolkit.interface.CommandLineInterface` and
+        :class:`~prompt_toolkit.document.Document`. It is called when the user
+        accepts input.
+    """
+    def __init__(self, handler=None):
+        assert handler is None or callable(handler)
+        self.handler = handler
+
+    @classmethod
+    def run_in_terminal(cls, handler, render_cli_done=False):
+        """
+        Create an :class:`.AcceptAction` that runs the given handler in the
+        terminal.
+
+        :param render_cli_done: When True, render the interface in the 'Done'
+                state first, then execute the function. If False, erase the
+                interface instead.
+        """
+        def _handler(cli, buffer):
+            cli.run_in_terminal(lambda: handler(cli, buffer), render_cli_done=render_cli_done)
+        return AcceptAction(handler=_handler)
+
+    @property
+    def is_returnable(self):
+        """
+        True when there is something handling accept.
+        """
+        return bool(self.handler)
+
+    def validate_and_handle(self, cli, buffer):
+        """
+        Validate buffer and handle the accept action.
+        """
+        if buffer.validate():
+            if self.handler:
+                self.handler(cli, buffer)
+
+            buffer.append_to_history()
+
+
+def _return_document_handler(cli, buffer):
+    # Set return value.
+    cli.set_return_value(buffer.document)
+
+    # Make sure that if we run this UI again, that we reset this buffer, next
+    # time.
+    def reset_this_buffer():
+        buffer.reset()
+    cli.pre_run_callables.append(reset_this_buffer)
+
+
+AcceptAction.RETURN_DOCUMENT = AcceptAction(_return_document_handler)
+AcceptAction.IGNORE = AcceptAction(handler=None)
+
+
+class ValidationState(object):
+    " The validation state of a buffer. This is set after the validation. "
+    VALID = 'VALID'
+    INVALID = 'INVALID'
+    UNKNOWN = 'UNKNOWN'
+
+
+class CompletionState(object):
+    """
+    Immutable class that contains a completion state.
+    """
+    def __init__(self, original_document, current_completions=None, complete_index=None):
+        #: Document as it was when the completion started.
+        self.original_document = original_document
+
+        #: List of all the current Completion instances which are possible at
+        #: this point.
+        self.current_completions = current_completions or []
+
+        #: Position in the `current_completions` array.
+        #: This can be `None` to indicate "no completion", the original text.
+        self.complete_index = complete_index  # Position in the `_completions` array.
+
+    def __repr__(self):
+        return '%s(%r, <%r> completions, index=%r)' % (
+            self.__class__.__name__,
+            self.original_document, len(self.current_completions), self.complete_index)
+
+    def go_to_index(self, index):
+        """
+        Create a new :class:`.CompletionState` object with the new index.
+        """
+        return CompletionState(self.original_document, self.current_completions, complete_index=index)
+
+    def new_text_and_position(self):
+        """
+        Return (new_text, new_cursor_position) for this completion.
+        """
+        if self.complete_index is None:
+            return self.original_document.text, self.original_document.cursor_position
+        else:
+            original_text_before_cursor = self.original_document.text_before_cursor
+            original_text_after_cursor = self.original_document.text_after_cursor
+
+            c = self.current_completions[self.complete_index]
+            if c.start_position == 0:
+                before = original_text_before_cursor
+            else:
+                before = original_text_before_cursor[:c.start_position]
+
+            new_text = before + c.text + original_text_after_cursor
+            new_cursor_position = len(before) + len(c.text)
+            return new_text, new_cursor_position
+
+    @property
+    def current_completion(self):
+        """
+        Return the current completion, or return `None` when no completion is
+        selected.
+        """
+        if self.complete_index is not None:
+            return self.current_completions[self.complete_index]
+
+
+_QUOTED_WORDS_RE = re.compile(r"""(\s+|".*?"|'.*?')""")
+
+
+class YankNthArgState(object):
+    """
+    For yank-last-arg/yank-nth-arg: Keep track of where we are in the history.
+    """
+    def __init__(self, history_position=0, n=-1, previous_inserted_word=''):
+        self.history_position = history_position
+        self.previous_inserted_word = previous_inserted_word
+        self.n = n
+
+    def __repr__(self):
+        return '%s(history_position=%r, n=%r, previous_inserted_word=%r)' % (
+            self.__class__.__name__, self.history_position, self.n,
+            self.previous_inserted_word)
+
+
+class Buffer(object):
+    """
+    The core data structure that holds the text and cursor position of the
+    current input line and implements all text manupulations on top of it. It
+    also implements the history, undo stack and the completion state.
+
+    :param completer: :class:`~prompt_toolkit.completion.Completer` instance.
+    :param history: :class:`~prompt_toolkit.history.History` instance.
+    :param tempfile_suffix: Suffix to be appended to the tempfile for the 'open
+                           in editor' function.
+
+    Events:
+
+    :param on_text_changed: When the buffer text changes. (Callable on None.)
+    :param on_text_insert: When new text is inserted. (Callable on None.)
+    :param on_cursor_position_changed: When the cursor moves. (Callable on None.)
+
+    Filters:
+
+    :param is_multiline: :class:`~prompt_toolkit.filters.SimpleFilter` to
+        indicate whether we should consider this buffer a multiline input. If
+        so, key bindings can decide to insert newlines when pressing [Enter].
+        (Instead of accepting the input.)
+    :param complete_while_typing: :class:`~prompt_toolkit.filters.SimpleFilter`
+        instance. Decide whether or not to do asynchronous autocompleting while
+        typing.
+    :param enable_history_search: :class:`~prompt_toolkit.filters.SimpleFilter`
+        to indicate when up-arrow partial string matching is enabled. It is
+        adviced to not enable this at the same time as `complete_while_typing`,
+        because when there is an autocompletion found, the up arrows usually
+        browse through the completions, rather than through the history.
+    :param read_only: :class:`~prompt_toolkit.filters.SimpleFilter`. When True,
+        changes will not be allowed.
+    """
+    def __init__(self, completer=None, auto_suggest=None, history=None,
+                 validator=None, tempfile_suffix='',
+                 is_multiline=False, complete_while_typing=False,
+                 enable_history_search=False, initial_document=None,
+                 accept_action=AcceptAction.IGNORE, read_only=False,
+                 on_text_changed=None, on_text_insert=None, on_cursor_position_changed=None):
+
+        # Accept both filters and booleans as input.
+        enable_history_search = to_simple_filter(enable_history_search)
+        is_multiline = to_simple_filter(is_multiline)
+        complete_while_typing = to_simple_filter(complete_while_typing)
+        read_only = to_simple_filter(read_only)
+
+        # Validate input.
+        assert completer is None or isinstance(completer, Completer)
+        assert auto_suggest is None or isinstance(auto_suggest, AutoSuggest)
+        assert history is None or isinstance(history, History)
+        assert on_text_changed is None or callable(on_text_changed)
+        assert on_text_insert is None or callable(on_text_insert)
+        assert on_cursor_position_changed is None or callable(on_cursor_position_changed)
+
+        self.completer = completer
+        self.auto_suggest = auto_suggest
+        self.validator = validator
+        self.tempfile_suffix = tempfile_suffix
+        self.accept_action = accept_action
+
+        # Filters. (Usually, used by the key bindings to drive the buffer.)
+        self.is_multiline = is_multiline
+        self.complete_while_typing = complete_while_typing
+        self.enable_history_search = enable_history_search
+        self.read_only = read_only
+
+        # Text width. (For wrapping, used by the Vi 'gq' operator.)
+        self.text_width = 0
+
+        #: The command buffer history.
+        # Note that we shouldn't use a lazy 'or' here. bool(history) could be
+        # False when empty.
+        self.history = InMemoryHistory() if history is None else history
+
+        self.__cursor_position = 0
+
+        # Events
+        self.on_text_changed = Event(self, on_text_changed)
+        self.on_text_insert = Event(self, on_text_insert)
+        self.on_cursor_position_changed = Event(self, on_cursor_position_changed)
+
+        # Document cache. (Avoid creating new Document instances.)
+        self._document_cache = FastDictCache(Document, size=10)
+
+        self.reset(initial_document=initial_document)
+
+    def reset(self, initial_document=None, append_to_history=False):
+        """
+        :param append_to_history: Append current input to history first.
+        """
+        assert initial_document is None or isinstance(initial_document, Document)
+
+        if append_to_history:
+            self.append_to_history()
+
+        initial_document = initial_document or Document()
+
+        self.__cursor_position = initial_document.cursor_position
+
+        # `ValidationError` instance. (Will be set when the input is wrong.)
+        self.validation_error = None
+        self.validation_state = ValidationState.UNKNOWN
+
+        # State of the selection.
+        self.selection_state = None
+
+        # Multiple cursor mode. (When we press 'I' or 'A' in visual-block mode,
+        # we can insert text on multiple lines at once. This is implemented by
+        # using multiple cursors.)
+        self.multiple_cursor_positions = []
+
+        # When doing consecutive up/down movements, prefer to stay at this column.
+        self.preferred_column = None
+
+        # State of complete browser
+        self.complete_state = None  # For interactive completion through Ctrl-N/Ctrl-P.
+
+        # State of Emacs yank-nth-arg completion.
+        self.yank_nth_arg_state = None  # for yank-nth-arg.
+
+        # Remember the document that we had *right before* the last paste
+        # operation. This is used for rotating through the kill ring.
+        self.document_before_paste = None
+
+        # Current suggestion.
+        self.suggestion = None
+
+        # The history search text. (Used for filtering the history when we
+        # browse through it.)
+        self.history_search_text = None
+
+        # Undo/redo stacks
+        self._undo_stack = []  # Stack of (text, cursor_position)
+        self._redo_stack = []
+
+        #: The working lines. Similar to history, except that this can be
+        #: modified. The user can press arrow_up and edit previous entries.
+        #: Ctrl-C should reset this, and copy the whole history back in here.
+        #: Enter should process the current command and append to the real
+        #: history.
+        self._working_lines = self.history.strings[:]
+        self._working_lines.append(initial_document.text)
+        self.__working_index = len(self._working_lines) - 1
+
+    # <getters/setters>
+
+    def _set_text(self, value):
+        """ set text at current working_index. Return whether it changed. """
+        working_index = self.working_index
+        working_lines = self._working_lines
+
+        original_value = working_lines[working_index]
+        working_lines[working_index] = value
+
+        # Return True when this text has been changed.
+        if len(value) != len(original_value):
+            # For Python 2, it seems that when two strings have a different
+            # length and one is a prefix of the other, Python still scans
+            # character by character to see whether the strings are different.
+            # (Some benchmarking showed significant differences for big
+            # documents. >100,000 of lines.)
+            return True
+        elif value != original_value:
+            return True
+        return False
+
+    def _set_cursor_position(self, value):
+        """ Set cursor position. Return whether it changed. """
+        original_position = self.__cursor_position
+        self.__cursor_position = max(0, value)
+
+        return value != original_position
+
+    @property
+    def text(self):
+        return self._working_lines[self.working_index]
+
+    @text.setter
+    def text(self, value):
+        """
+        Setting text. (When doing this, make sure that the cursor_position is
+        valid for this text. text/cursor_position should be consistent at any time,
+        otherwise set a Document instead.)
+        """
+        assert isinstance(value, six.text_type), 'Got %r' % value
+        assert self.cursor_position <= len(value)
+
+        # Don't allow editing of read-only buffers.
+        if self.read_only():
+            raise EditReadOnlyBuffer()
+
+        changed = self._set_text(value)
+
+        if changed:
+            self._text_changed()
+
+            # Reset history search text.
+            self.history_search_text = None
+
+    @property
+    def cursor_position(self):
+        return self.__cursor_position
+
+    @cursor_position.setter
+    def cursor_position(self, value):
+        """
+        Setting cursor position.
+        """
+        assert isinstance(value, int)
+        assert value <= len(self.text)
+
+        changed = self._set_cursor_position(value)
+
+        if changed:
+            self._cursor_position_changed()
+
+    @property
+    def working_index(self):
+        return self.__working_index
+
+    @working_index.setter
+    def working_index(self, value):
+        if self.__working_index != value:
+            self.__working_index = value
+            self._text_changed()
+
+    def _text_changed(self):
+        # Remove any validation errors and complete state.
+        self.validation_error = None
+        self.validation_state = ValidationState.UNKNOWN
+        self.complete_state = None
+        self.yank_nth_arg_state = None
+        self.document_before_paste = None
+        self.selection_state = None
+        self.suggestion = None
+        self.preferred_column = None
+
+        # fire 'on_text_changed' event.
+        self.on_text_changed.fire()
+
+    def _cursor_position_changed(self):
+        # Remove any validation errors and complete state.
+        self.validation_error = None
+        self.validation_state = ValidationState.UNKNOWN
+        self.complete_state = None
+        self.yank_nth_arg_state = None
+        self.document_before_paste = None
+
+        # Unset preferred_column. (Will be set after the cursor movement, if
+        # required.)
+        self.preferred_column = None
+
+        # Note that the cursor position can change if we have a selection the
+        # new position of the cursor determines the end of the selection.
+
+        # fire 'on_cursor_position_changed' event.
+        self.on_cursor_position_changed.fire()
+
+    @property
+    def document(self):
+        """
+        Return :class:`~prompt_toolkit.document.Document` instance from the
+        current text, cursor position and selection state.
+        """
+        return self._document_cache[
+            self.text, self.cursor_position, self.selection_state]
+
+    @document.setter
+    def document(self, value):
+        """
+        Set :class:`~prompt_toolkit.document.Document` instance.
+
+        This will set both the text and cursor position at the same time, but
+        atomically. (Change events will be triggered only after both have been set.)
+        """
+        self.set_document(value)
+
+    def set_document(self, value, bypass_readonly=False):
+        """
+        Set :class:`~prompt_toolkit.document.Document` instance. Like the
+        ``document`` property, but accept an ``bypass_readonly`` argument.
+
+        :param bypass_readonly: When True, don't raise an
+                                :class:`.EditReadOnlyBuffer` exception, even
+                                when the buffer is read-only.
+        """
+        assert isinstance(value, Document)
+
+        # Don't allow editing of read-only buffers.
+        if not bypass_readonly and self.read_only():
+            raise EditReadOnlyBuffer()
+
+        # Set text and cursor position first.
+        text_changed = self._set_text(value.text)
+        cursor_position_changed = self._set_cursor_position(value.cursor_position)
+
+        # Now handle change events. (We do this when text/cursor position is
+        # both set and consistent.)
+        if text_changed:
+            self._text_changed()
+
+        if cursor_position_changed:
+            self._cursor_position_changed()
+
+    # End of <getters/setters>
+
+    def save_to_undo_stack(self, clear_redo_stack=True):
+        """
+        Safe current state (input text and cursor position), so that we can
+        restore it by calling undo.
+        """
+        # Safe if the text is different from the text at the top of the stack
+        # is different. If the text is the same, just update the cursor position.
+        if self._undo_stack and self._undo_stack[-1][0] == self.text:
+            self._undo_stack[-1] = (self._undo_stack[-1][0], self.cursor_position)
+        else:
+            self._undo_stack.append((self.text, self.cursor_position))
+
+        # Saving anything to the undo stack, clears the redo stack.
+        if clear_redo_stack:
+            self._redo_stack = []
+
+    def transform_lines(self, line_index_iterator, transform_callback):
+        """
+        Transforms the text on a range of lines.
+        When the iterator yield an index not in the range of lines that the
+        document contains, it skips them silently.
+
+        To uppercase some lines::
+
+            new_text = transform_lines(range(5,10), lambda text: text.upper())
+
+        :param line_index_iterator: Iterator of line numbers (int)
+        :param transform_callback: callable that takes the original text of a
+                                   line, and return the new text for this line.
+
+        :returns: The new text.
+        """
+        # Split lines
+        lines = self.text.split('\n')
+
+        # Apply transformation
+        for index in line_index_iterator:
+            try:
+                lines[index] = transform_callback(lines[index])
+            except IndexError:
+                pass
+
+        return '\n'.join(lines)
+
+    def transform_current_line(self, transform_callback):
+        """
+        Apply the given transformation function to the current line.
+
+        :param transform_callback: callable that takes a string and return a new string.
+        """
+        document = self.document
+        a = document.cursor_position + document.get_start_of_line_position()
+        b = document.cursor_position + document.get_end_of_line_position()
+        self.text = (
+            document.text[:a] +
+            transform_callback(document.text[a:b]) +
+            document.text[b:])
+
+    def transform_region(self, from_, to, transform_callback):
+        """
+        Transform a part of the input string.
+
+        :param from_: (int) start position.
+        :param to: (int) end position.
+        :param transform_callback: Callable which accepts a string and returns
+            the transformed string.
+        """
+        assert from_ < to
+
+        self.text = ''.join([
+            self.text[:from_] +
+            transform_callback(self.text[from_:to]) +
+            self.text[to:]
+        ])
+
+    def cursor_left(self, count=1):
+        self.cursor_position += self.document.get_cursor_left_position(count=count)
+
+    def cursor_right(self, count=1):
+        self.cursor_position += self.document.get_cursor_right_position(count=count)
+
+    def cursor_up(self, count=1):
+        """ (for multiline edit). Move cursor to the previous line.  """
+        original_column = self.preferred_column or self.document.cursor_position_col
+        self.cursor_position += self.document.get_cursor_up_position(
+            count=count, preferred_column=original_column)
+
+        # Remember the original column for the next up/down movement.
+        self.preferred_column = original_column
+
+    def cursor_down(self, count=1):
+        """ (for multiline edit). Move cursor to the next line.  """
+        original_column = self.preferred_column or self.document.cursor_position_col
+        self.cursor_position += self.document.get_cursor_down_position(
+            count=count, preferred_column=original_column)
+
+        # Remember the original column for the next up/down movement.
+        self.preferred_column = original_column
+
+    def auto_up(self, count=1, go_to_start_of_line_if_history_changes=False):
+        """
+        If we're not on the first line (of a multiline input) go a line up,
+        otherwise go back in history. (If nothing is selected.)
+        """
+        if self.complete_state:
+            self.complete_previous(count=count)
+        elif self.document.cursor_position_row > 0:
+            self.cursor_up(count=count)
+        elif not self.selection_state:
+            self.history_backward(count=count)
+
+            # Go to the start of the line?
+            if go_to_start_of_line_if_history_changes:
+                self.cursor_position += self.document.get_start_of_line_position()
+
+    def auto_down(self, count=1, go_to_start_of_line_if_history_changes=False):
+        """
+        If we're not on the last line (of a multiline input) go a line down,
+        otherwise go forward in history. (If nothing is selected.)
+        """
+        if self.complete_state:
+            self.complete_next(count=count)
+        elif self.document.cursor_position_row < self.document.line_count - 1:
+            self.cursor_down(count=count)
+        elif not self.selection_state:
+            self.history_forward(count=count)
+
+            # Go to the start of the line?
+            if go_to_start_of_line_if_history_changes:
+                self.cursor_position += self.document.get_start_of_line_position()
+
+    def delete_before_cursor(self, count=1):
+        """
+        Delete specified number of characters before cursor and return the
+        deleted text.
+        """
+        assert count >= 0
+        deleted = ''
+
+        if self.cursor_position > 0:
+            deleted = self.text[self.cursor_position - count:self.cursor_position]
+
+            new_text = self.text[:self.cursor_position - count] + self.text[self.cursor_position:]
+            new_cursor_position = self.cursor_position - len(deleted)
+
+            # Set new Document atomically.
+            self.document = Document(new_text, new_cursor_position)
+
+        return deleted
+
+    def delete(self, count=1):
+        """
+        Delete specified number of characters and Return the deleted text.
+        """
+        if self.cursor_position < len(self.text):
+            deleted = self.document.text_after_cursor[:count]
+            self.text = self.text[:self.cursor_position] + \
+                self.text[self.cursor_position + len(deleted):]
+            return deleted
+        else:
+            return ''
+
+    def join_next_line(self, separator=' '):
+        """
+        Join the next line to the current one by deleting the line ending after
+        the current line.
+        """
+        if not self.document.on_last_line:
+            self.cursor_position += self.document.get_end_of_line_position()
+            self.delete()
+
+            # Remove spaces.
+            self.text = (self.document.text_before_cursor + separator +
+                         self.document.text_after_cursor.lstrip(' '))
+
+    def join_selected_lines(self, separator=' '):
+        """
+        Join the selected lines.
+        """
+        assert self.selection_state
+
+        # Get lines.
+        from_, to = sorted([self.cursor_position, self.selection_state.original_cursor_position])
+
+        before = self.text[:from_]
+        lines = self.text[from_:to].splitlines()
+        after = self.text[to:]
+
+        # Replace leading spaces with just one space.
+        lines = [l.lstrip(' ') + separator for l in lines]
+
+        # Set new document.
+        self.document = Document(text=before + ''.join(lines) + after,
+                                 cursor_position=len(before + ''.join(lines[:-1])) - 1)
+
+    def swap_characters_before_cursor(self):
+        """
+        Swap the last two characters before the cursor.
+        """
+        pos = self.cursor_position
+
+        if pos >= 2:
+            a = self.text[pos - 2]
+            b = self.text[pos - 1]
+
+            self.text = self.text[:pos-2] + b + a + self.text[pos:]
+
+    def go_to_history(self, index):
+        """
+        Go to this item in the history.
+        """
+        if index < len(self._working_lines):
+            self.working_index = index
+            self.cursor_position = len(self.text)
+
+    def complete_next(self, count=1, disable_wrap_around=False):
+        """
+        Browse to the next completions.
+        (Does nothing if there are no completion.)
+        """
+        if self.complete_state:
+            completions_count = len(self.complete_state.current_completions)
+
+            if self.complete_state.complete_index is None:
+                index = 0
+            elif self.complete_state.complete_index == completions_count - 1:
+                index = None
+
+                if disable_wrap_around:
+                    return
+            else:
+                index = min(completions_count-1, self.complete_state.complete_index + count)
+            self.go_to_completion(index)
+
+    def complete_previous(self, count=1, disable_wrap_around=False):
+        """
+        Browse to the previous completions.
+        (Does nothing if there are no completion.)
+        """
+        if self.complete_state:
+            if self.complete_state.complete_index == 0:
+                index = None
+
+                if disable_wrap_around:
+                    return
+            elif self.complete_state.complete_index is None:
+                index = len(self.complete_state.current_completions) - 1
+            else:
+                index = max(0, self.complete_state.complete_index - count)
+
+            self.go_to_completion(index)
+
+    def cancel_completion(self):
+        """
+        Cancel completion, go back to the original text.
+        """
+        if self.complete_state:
+            self.go_to_completion(None)
+            self.complete_state = None
+
+    def set_completions(self, completions, go_to_first=True, go_to_last=False):
+        """
+        Start completions. (Generate list of completions and initialize.)
+        """
+        assert not (go_to_first and go_to_last)
+
+        # Generate list of all completions.
+        if completions is None:
+            if self.completer:
+                completions = list(self.completer.get_completions(
+                    self.document,
+                    CompleteEvent(completion_requested=True)
+                ))
+            else:
+                completions = []
+
+        # Set `complete_state`.
+        if completions:
+            self.complete_state = CompletionState(
+                original_document=self.document,
+                current_completions=completions)
+            if go_to_first:
+                self.go_to_completion(0)
+            elif go_to_last:
+                self.go_to_completion(len(completions) - 1)
+            else:
+                self.go_to_completion(None)
+
+        else:
+            self.complete_state = None
+
+    def start_history_lines_completion(self):
+        """
+        Start a completion based on all the other lines in the document and the
+        history.
+        """
+        found_completions = set()
+        completions = []
+
+        # For every line of the whole history, find matches with the current line.
+        current_line = self.document.current_line_before_cursor.lstrip()
+
+        for i, string in enumerate(self._working_lines):
+            for j, l in enumerate(string.split('\n')):
+                l = l.strip()
+                if l and l.startswith(current_line):
+                    # When a new line has been found.
+                    if l not in found_completions:
+                        found_completions.add(l)
+
+                        # Create completion.
+                        if i == self.working_index:
+                            display_meta = "Current, line %s" % (j+1)
+                        else:
+                            display_meta = "History %s, line %s" % (i+1, j+1)
+
+                        completions.append(Completion(
+                            l,
+                            start_position=-len(current_line),
+                            display_meta=display_meta))
+
+        self.set_completions(completions=completions[::-1])
+
+    def go_to_completion(self, index):
+        """
+        Select a completion from the list of current completions.
+        """
+        assert index is None or isinstance(index, int)
+        assert self.complete_state
+
+        # Set new completion
+        state = self.complete_state.go_to_index(index)
+
+        # Set text/cursor position
+        new_text, new_cursor_position = state.new_text_and_position()
+        self.document = Document(new_text, new_cursor_position)
+
+        # (changing text/cursor position will unset complete_state.)
+        self.complete_state = state
+
+    def apply_completion(self, completion):
+        """
+        Insert a given completion.
+        """
+        assert isinstance(completion, Completion)
+
+        # If there was already a completion active, cancel that one.
+        if self.complete_state:
+            self.go_to_completion(None)
+        self.complete_state = None
+
+        # Insert text from the given completion.
+        self.delete_before_cursor(-completion.start_position)
+        self.insert_text(completion.text)
+
+    def _set_history_search(self):
+        """ Set `history_search_text`. """
+        if self.enable_history_search():
+            if self.history_search_text is None:
+                self.history_search_text = self.document.text_before_cursor
+        else:
+            self.history_search_text = None
+
+    def _history_matches(self, i):
+        """
+        True when the current entry matches the history search.
+        (when we don't have history search, it's also True.)
+        """
+        return (self.history_search_text is None or
+                self._working_lines[i].startswith(self.history_search_text))
+
+    def history_forward(self, count=1):
+        """
+        Move forwards through the history.
+
+        :param count: Amount of items to move forward.
+        """
+        self._set_history_search()
+
+        # Go forward in history.
+        found_something = False
+
+        for i in range(self.working_index + 1, len(self._working_lines)):
+            if self._history_matches(i):
+                self.working_index = i
+                count -= 1
+                found_something = True
+            if count == 0:
+                break
+
+        # If we found an entry, move cursor to the end of the first line.
+        if found_something:
+            self.cursor_position = 0
+            self.cursor_position += self.document.get_end_of_line_position()
+
+    def history_backward(self, count=1):
+        """
+        Move backwards through history.
+        """
+        self._set_history_search()
+
+        # Go back in history.
+        found_something = False
+
+        for i in range(self.working_index - 1, -1, -1):
+            if self._history_matches(i):
+                self.working_index = i
+                count -= 1
+                found_something = True
+            if count == 0:
+                break
+
+        # If we move to another entry, move cursor to the end of the line.
+        if found_something:
+            self.cursor_position = len(self.text)
+
+    def yank_nth_arg(self, n=None, _yank_last_arg=False):
+        """
+        Pick nth word from previous history entry (depending on current
+        `yank_nth_arg_state`) and insert it at current position. Rotate through
+        history if called repeatedly. If no `n` has been given, take the first
+        argument. (The second word.)
+
+        :param n: (None or int), The index of the word from the previous line
+            to take.
+        """
+        assert n is None or isinstance(n, int)
+
+        if not len(self.history):
+            return
+
+        # Make sure we have a `YankNthArgState`.
+        if self.yank_nth_arg_state is None:
+            state = YankNthArgState(n=-1 if _yank_last_arg else 1)
+        else:
+            state = self.yank_nth_arg_state
+
+        if n is not None:
+            state.n = n
+
+        # Get new history position.
+        new_pos = state.history_position - 1
+        if -new_pos > len(self.history):
+            new_pos = -1
+
+        # Take argument from line.
+        line = self.history[new_pos]
+
+        words = [w.strip() for w in _QUOTED_WORDS_RE.split(line)]
+        words = [w for w in words if w]
+        try:
+            word = words[state.n]
+        except IndexError:
+            word = ''
+
+        # Insert new argument.
+        if state.previous_inserted_word:
+            self.delete_before_cursor(len(state.previous_inserted_word))
+        self.insert_text(word)
+
+        # Save state again for next completion. (Note that the 'insert'
+        # operation from above clears `self.yank_nth_arg_state`.)
+        state.previous_inserted_word = word
+        state.history_position = new_pos
+        self.yank_nth_arg_state = state
+
+    def yank_last_arg(self, n=None):
+        """
+        Like `yank_nth_arg`, but if no argument has been given, yank the last
+        word by default.
+        """
+        self.yank_nth_arg(n=n, _yank_last_arg=True)
+
+    def start_selection(self, selection_type=SelectionType.CHARACTERS):
+        """
+        Take the current cursor position as the start of this selection.
+        """
+        self.selection_state = SelectionState(self.cursor_position, selection_type)
+
+    def copy_selection(self, _cut=False):
+        """
+        Copy selected text and return :class:`.ClipboardData` instance.
+        """
+        new_document, clipboard_data = self.document.cut_selection()
+        if _cut:
+            self.document = new_document
+
+        self.selection_state = None
+        return clipboard_data
+
+    def cut_selection(self):
+        """
+        Delete selected text and return :class:`.ClipboardData` instance.
+        """
+        return self.copy_selection(_cut=True)
+
+    def paste_clipboard_data(self, data, paste_mode=PasteMode.EMACS, count=1):
+        """
+        Insert the data from the clipboard.
+        """
+        assert isinstance(data, ClipboardData)
+        assert paste_mode in (PasteMode.VI_BEFORE, PasteMode.VI_AFTER, PasteMode.EMACS)
+
+        original_document = self.document
+        self.document = self.document.paste_clipboard_data(data, paste_mode=paste_mode, count=count)
+
+        # Remember original document. This assignment should come at the end,
+        # because assigning to 'document' will erase it.
+        self.document_before_paste = original_document
+
+    def newline(self, copy_margin=True):
+        """
+        Insert a line ending at the current position.
+        """
+        if copy_margin:
+            self.insert_text('\n' + self.document.leading_whitespace_in_current_line)
+        else:
+            self.insert_text('\n')
+
+    def insert_line_above(self, copy_margin=True):
+        """
+        Insert a new line above the current one.
+        """
+        if copy_margin:
+            insert = self.document.leading_whitespace_in_current_line + '\n'
+        else:
+            insert = '\n'
+
+        self.cursor_position += self.document.get_start_of_line_position()
+        self.insert_text(insert)
+        self.cursor_position -= 1
+
+    def insert_line_below(self, copy_margin=True):
+        """
+        Insert a new line below the current one.
+        """
+        if copy_margin:
+            insert = '\n' + self.document.leading_whitespace_in_current_line
+        else:
+            insert = '\n'
+
+        self.cursor_position += self.document.get_end_of_line_position()
+        self.insert_text(insert)
+
+    def insert_text(self, data, overwrite=False, move_cursor=True, fire_event=True):
+        """
+        Insert characters at cursor position.
+
+        :param fire_event: Fire `on_text_insert` event. This is mainly used to
+            trigger autocompletion while typing.
+        """
+        # Original text & cursor position.
+        otext = self.text
+        ocpos = self.cursor_position
+
+        # In insert/text mode.
+        if overwrite:
+            # Don't overwrite the newline itself. Just before the line ending,
+            # it should act like insert mode.
+            overwritten_text = otext[ocpos:ocpos + len(data)]
+            if '\n' in overwritten_text:
+                overwritten_text = overwritten_text[:overwritten_text.find('\n')]
+
+            self.text = otext[:ocpos] + data + otext[ocpos + len(overwritten_text):]
+        else:
+            self.text = otext[:ocpos] + data + otext[ocpos:]
+
+        if move_cursor:
+            self.cursor_position += len(data)
+
+        # Fire 'on_text_insert' event.
+        if fire_event:
+            self.on_text_insert.fire()
+
+    def undo(self):
+        # Pop from the undo-stack until we find a text that if different from
+        # the current text. (The current logic of `save_to_undo_stack` will
+        # cause that the top of the undo stack is usually the same as the
+        # current text, so in that case we have to pop twice.)
+        while self._undo_stack:
+            text, pos = self._undo_stack.pop()
+
+            if text != self.text:
+                # Push current text to redo stack.
+                self._redo_stack.append((self.text, self.cursor_position))
+
+                # Set new text/cursor_position.
+                self.document = Document(text, cursor_position=pos)
+                break
+
+    def redo(self):
+        if self._redo_stack:
+            # Copy current state on undo stack.
+            self.save_to_undo_stack(clear_redo_stack=False)
+
+            # Pop state from redo stack.
+            text, pos = self._redo_stack.pop()
+            self.document = Document(text, cursor_position=pos)
+
+    def validate(self):
+        """
+        Returns `True` if valid.
+        """
+        # Don't call the validator again, if it was already called for the
+        # current input.
+        if self.validation_state != ValidationState.UNKNOWN:
+            return self.validation_state == ValidationState.VALID
+
+        # Validate first. If not valid, set validation exception.
+        if self.validator:
+            try:
+                self.validator.validate(self.document)
+            except ValidationError as e:
+                # Set cursor position (don't allow invalid values.)
+                cursor_position = e.cursor_position
+                self.cursor_position = min(max(0, cursor_position), len(self.text))
+
+                self.validation_state = ValidationState.INVALID
+                self.validation_error = e
+                return False
+
+        self.validation_state = ValidationState.VALID
+        self.validation_error = None
+        return True
+
+    def append_to_history(self):
+        """
+        Append the current input to the history.
+        (Only if valid input.)
+        """
+        # Validate first. If not valid, set validation exception.
+        if not self.validate():
+            return
+
+        # Save at the tail of the history. (But don't if the last entry the
+        # history is already the same.)
+        if self.text and (not len(self.history) or self.history[-1] != self.text):
+            self.history.append(self.text)
+
+    def _search(self, search_state, include_current_position=False, count=1):
+        """
+        Execute search. Return (working_index, cursor_position) tuple when this
+        search is applied. Returns `None` when this text cannot be found.
+        """
+        assert isinstance(search_state, SearchState)
+        assert isinstance(count, int) and count > 0
+
+        text = search_state.text
+        direction = search_state.direction
+        ignore_case = search_state.ignore_case()
+
+        def search_once(working_index, document):
+            """
+            Do search one time.
+            Return (working_index, document) or `None`
+            """
+            if direction == IncrementalSearchDirection.FORWARD:
+                # Try find at the current input.
+                new_index = document.find(
+                   text, include_current_position=include_current_position,
+                   ignore_case=ignore_case)
+
+                if new_index is not None:
+                    return (working_index,
+                            Document(document.text, document.cursor_position + new_index))
+                else:
+                    # No match, go forward in the history. (Include len+1 to wrap around.)
+                    # (Here we should always include all cursor positions, because
+                    # it's a different line.)
+                    for i in range(working_index + 1, len(self._working_lines) + 1):
+                        i %= len(self._working_lines)
+
+                        document = Document(self._working_lines[i], 0)
+                        new_index = document.find(text, include_current_position=True,
+                                                  ignore_case=ignore_case)
+                        if new_index is not None:
+                            return (i, Document(document.text, new_index))
+            else:
+                # Try find at the current input.
+                new_index = document.find_backwards(
+                    text, ignore_case=ignore_case)
+
+                if new_index is not None:
+                    return (working_index,
+                            Document(document.text, document.cursor_position + new_index))
+                else:
+                    # No match, go back in the history. (Include -1 to wrap around.)
+                    for i in range(working_index - 1, -2, -1):
+                        i %= len(self._working_lines)
+
+                        document = Document(self._working_lines[i], len(self._working_lines[i]))
+                        new_index = document.find_backwards(
+                            text, ignore_case=ignore_case)
+                        if new_index is not None:
+                            return (i, Document(document.text, len(document.text) + new_index))
+
+        # Do 'count' search iterations.
+        working_index = self.working_index
+        document = self.document
+        for _ in range(count):
+            result = search_once(working_index, document)
+            if result is None:
+                return  # Nothing found.
+            else:
+                working_index, document = result
+
+        return (working_index, document.cursor_position)
+
+    def document_for_search(self, search_state):
+        """
+        Return a :class:`~prompt_toolkit.document.Document` instance that has
+        the text/cursor position for this search, if we would apply it. This
+        will be used in the
+        :class:`~prompt_toolkit.layout.controls.BufferControl` to display
+        feedback while searching.
+        """
+        search_result = self._search(search_state, include_current_position=True)
+
+        if search_result is None:
+            return self.document
+        else:
+            working_index, cursor_position = search_result
+
+            # Keep selection, when `working_index` was not changed.
+            if working_index == self.working_index:
+                selection = self.selection_state
+            else:
+                selection = None
+
+            return Document(self._working_lines[working_index],
+                            cursor_position, selection=selection)
+
+    def get_search_position(self, search_state, include_current_position=True, count=1):
+        """
+        Get the cursor position for this search.
+        (This operation won't change the `working_index`. It's won't go through
+        the history. Vi text objects can't span multiple items.)
+        """
+        search_result = self._search(
+            search_state, include_current_position=include_current_position, count=count)
+
+        if search_result is None:
+            return self.cursor_position
+        else:
+            working_index, cursor_position = search_result
+            return cursor_position
+
+    def apply_search(self, search_state, include_current_position=True, count=1):
+        """
+        Apply search. If something is found, set `working_index` and
+        `cursor_position`.
+        """
+        search_result = self._search(
+            search_state, include_current_position=include_current_position, count=count)
+
+        if search_result is not None:
+            working_index, cursor_position = search_result
+            self.working_index = working_index
+            self.cursor_position = cursor_position
+
+    def exit_selection(self):
+        self.selection_state = None
+
+    def open_in_editor(self, cli):
+        """
+        Open code in editor.
+
+        :param cli: :class:`~prompt_toolkit.interface.CommandLineInterface`
+            instance.
+        """
+        if self.read_only():
+            raise EditReadOnlyBuffer()
+
+        # Write to temporary file
+        descriptor, filename = tempfile.mkstemp(self.tempfile_suffix)
+        os.write(descriptor, self.text.encode('utf-8'))
+        os.close(descriptor)
+
+        # Open in editor
+        # (We need to use `cli.run_in_terminal`, because not all editors go to
+        # the alternate screen buffer, and some could influence the cursor
+        # position.)
+        succes = cli.run_in_terminal(lambda: self._open_file_in_editor(filename))
+
+        # Read content again.
+        if succes:
+            with open(filename, 'rb') as f:
+                text = f.read().decode('utf-8')
+
+                # Drop trailing newline. (Editors are supposed to add it at the
+                # end, but we don't need it.)
+                if text.endswith('\n'):
+                    text = text[:-1]
+
+                self.document = Document(
+                    text=text,
+                    cursor_position=len(text))
+
+        # Clean up temp file.
+        os.remove(filename)
+
+    def _open_file_in_editor(self, filename):
+        """
+        Call editor executable.
+
+        Return True when we received a zero return code.
+        """
+        # If the 'VISUAL' or 'EDITOR' environment variable has been set, use that.
+        # Otherwise, fall back to the first available editor that we can find.
+        visual = os.environ.get('VISUAL')
+        editor = os.environ.get('EDITOR')
+
+        editors = [
+            visual,
+            editor,
+
+            # Order of preference.
+            '/usr/bin/editor',
+            '/usr/bin/nano',
+            '/usr/bin/pico',
+            '/usr/bin/vi',
+            '/usr/bin/emacs',
+        ]
+
+        for e in editors:
+            if e:
+                try:
+                    # Use 'shlex.split()', because $VISUAL can contain spaces
+                    # and quotes.
+                    returncode = subprocess.call(shlex.split(e) + [filename])
+                    return returncode == 0
+
+                except OSError:
+                    # Executable does not exist, try the next one.
+                    pass
+
+        return False
+
+
+def indent(buffer, from_row, to_row, count=1):
+    """
+    Indent text of a :class:`.Buffer` object.
+    """
+    current_row = buffer.document.cursor_position_row
+    line_range = range(from_row, to_row)
+
+    # Apply transformation.
+    new_text = buffer.transform_lines(line_range, lambda l: '    ' * count + l)
+    buffer.document = Document(
+        new_text,
+        Document(new_text).translate_row_col_to_index(current_row, 0))
+
+    # Go to the start of the line.
+    buffer.cursor_position += buffer.document.get_start_of_line_position(after_whitespace=True)
+
+
+def unindent(buffer, from_row, to_row, count=1):
+    """
+    Unindent text of a :class:`.Buffer` object.
+    """
+    current_row = buffer.document.cursor_position_row
+    line_range = range(from_row, to_row)
+
+    def transform(text):
+        remove = '    ' * count
+        if text.startswith(remove):
+            return text[len(remove):]
+        else:
+            return text.lstrip()
+
+    # Apply transformation.
+    new_text = buffer.transform_lines(line_range, transform)
+    buffer.document = Document(
+        new_text,
+        Document(new_text).translate_row_col_to_index(current_row, 0))
+
+    # Go to the start of the line.
+    buffer.cursor_position += buffer.document.get_start_of_line_position(after_whitespace=True)
+
+
+def reshape_text(buffer, from_row, to_row):
+    """
+    Reformat text, taking the width into account.
+    `to_row` is included.
+    (Vi 'gq' operator.)
+    """
+    lines = buffer.text.splitlines(True)
+    lines_before = lines[:from_row]
+    lines_after = lines[to_row + 1:]
+    lines_to_reformat = lines[from_row:to_row + 1]
+
+    if lines_to_reformat:
+        # Take indentation from the first line.
+        length = re.search(r'^\s*', lines_to_reformat[0]).end()
+        indent = lines_to_reformat[0][:length].replace('\n', '')
+
+        # Now, take all the 'words' from the lines to be reshaped.
+        words = ''.join(lines_to_reformat).split()
+
+        # And reshape.
+        width = (buffer.text_width or 80) - len(indent)
+        reshaped_text = [indent]
+        current_width = 0
+        for w in words:
+            if current_width:
+                if len(w) + current_width + 1 > width:
+                    reshaped_text.append('\n')
+                    reshaped_text.append(indent)
+                    current_width = 0
+                else:
+                    reshaped_text.append(' ')
+                    current_width += 1
+
+            reshaped_text.append(w)
+            current_width += len(w)
+
+        if reshaped_text[-1] != '\n':
+            reshaped_text.append('\n')
+
+        # Apply result.
+        buffer.document = Document(
+            text=''.join(lines_before + reshaped_text + lines_after),
+            cursor_position=len(''.join(lines_before + reshaped_text)))