Vehicle-Anti-Theft-Face-Rec.../venv/Lib/site-packages/prompt_toolkit/layout/layout.py

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2020-11-12 16:05:57 +00:00
"""
Wrapper for the layout.
"""
from typing import Dict, Generator, Iterable, List, Optional, Union
from prompt_toolkit.buffer import Buffer
from .containers import (
AnyContainer,
ConditionalContainer,
Container,
Window,
to_container,
)
from .controls import BufferControl, SearchBufferControl, UIControl
__all__ = [
"Layout",
"InvalidLayoutError",
"walk",
]
FocusableElement = Union[str, Buffer, UIControl, AnyContainer]
class Layout:
"""
The layout for a prompt_toolkit
:class:`~prompt_toolkit.application.Application`.
This also keeps track of which user control is focused.
:param container: The "root" container for the layout.
:param focused_element: element to be focused initially. (Can be anything
the `focus` function accepts.)
"""
def __init__(
self,
container: AnyContainer,
focused_element: Optional[FocusableElement] = None,
) -> None:
self.container = to_container(container)
self._stack: List[Window] = []
# Map search BufferControl back to the original BufferControl.
# This is used to keep track of when exactly we are searching, and for
# applying the search.
# When a link exists in this dictionary, that means the search is
# currently active.
# Map: search_buffer_control -> original buffer control.
self.search_links: Dict[SearchBufferControl, BufferControl] = {}
# Mapping that maps the children in the layout to their parent.
# This relationship is calculated dynamically, each time when the UI
# is rendered. (UI elements have only references to their children.)
self._child_to_parent: Dict[Container, Container] = {}
if focused_element is None:
try:
self._stack.append(next(self.find_all_windows()))
except StopIteration as e:
raise InvalidLayoutError(
"Invalid layout. The layout does not contain any Window object."
) from e
else:
self.focus(focused_element)
# List of visible windows.
self.visible_windows: List[Window] = [] # List of `Window` objects.
def __repr__(self) -> str:
return "Layout(%r, current_window=%r)" % (self.container, self.current_window)
def find_all_windows(self) -> Generator[Window, None, None]:
"""
Find all the :class:`.UIControl` objects in this layout.
"""
for item in self.walk():
if isinstance(item, Window):
yield item
def find_all_controls(self) -> Iterable[UIControl]:
for container in self.find_all_windows():
yield container.content
def focus(self, value: FocusableElement) -> None:
"""
Focus the given UI element.
`value` can be either:
- a :class:`.UIControl`
- a :class:`.Buffer` instance or the name of a :class:`.Buffer`
- a :class:`.Window`
- Any container object. In this case we will focus the :class:`.Window`
from this container that was focused most recent, or the very first
focusable :class:`.Window` of the container.
"""
# BufferControl by buffer name.
if isinstance(value, str):
for control in self.find_all_controls():
if isinstance(control, BufferControl) and control.buffer.name == value:
self.focus(control)
return
raise ValueError(
"Couldn't find Buffer in the current layout: %r." % (value,)
)
# BufferControl by buffer object.
elif isinstance(value, Buffer):
for control in self.find_all_controls():
if isinstance(control, BufferControl) and control.buffer == value:
self.focus(control)
return
raise ValueError(
"Couldn't find Buffer in the current layout: %r." % (value,)
)
# Focus UIControl.
elif isinstance(value, UIControl):
if value not in self.find_all_controls():
raise ValueError(
"Invalid value. Container does not appear in the layout."
)
if not value.is_focusable():
raise ValueError("Invalid value. UIControl is not focusable.")
self.current_control = value
# Otherwise, expecting any Container object.
else:
value = to_container(value)
if isinstance(value, Window):
# This is a `Window`: focus that.
if value not in self.find_all_windows():
raise ValueError(
"Invalid value. Window does not appear in the layout: %r"
% (value,)
)
self.current_window = value
else:
# Focus a window in this container.
# If we have many windows as part of this container, and some
# of them have been focused before, take the last focused
# item. (This is very useful when the UI is composed of more
# complex sub components.)
windows = []
for c in walk(value, skip_hidden=True):
if isinstance(c, Window) and c.content.is_focusable():
windows.append(c)
# Take the first one that was focused before.
for w in reversed(self._stack):
if w in windows:
self.current_window = w
return
# None was focused before: take the very first focusable window.
if windows:
self.current_window = windows[0]
return
raise ValueError(
"Invalid value. Container cannot be focused: %r" % (value,)
)
def has_focus(self, value: FocusableElement) -> bool:
"""
Check whether the given control has the focus.
:param value: :class:`.UIControl` or :class:`.Window` instance.
"""
if isinstance(value, str):
if self.current_buffer is None:
return False
return self.current_buffer.name == value
if isinstance(value, Buffer):
return self.current_buffer == value
if isinstance(value, UIControl):
return self.current_control == value
else:
value = to_container(value)
if isinstance(value, Window):
return self.current_window == value
else:
# Check whether this "container" is focused. This is true if
# one of the elements inside is focused.
for element in walk(value):
if element == self.current_window:
return True
return False
@property
def current_control(self) -> UIControl:
"""
Get the :class:`.UIControl` to currently has the focus.
"""
return self._stack[-1].content
@current_control.setter
def current_control(self, control: UIControl) -> None:
"""
Set the :class:`.UIControl` to receive the focus.
"""
for window in self.find_all_windows():
if window.content == control:
self.current_window = window
return
raise ValueError("Control not found in the user interface.")
@property
def current_window(self) -> Window:
" Return the :class:`.Window` object that is currently focused. "
return self._stack[-1]
@current_window.setter
def current_window(self, value: Window):
" Set the :class:`.Window` object to be currently focused. "
self._stack.append(value)
@property
def is_searching(self) -> bool:
" True if we are searching right now. "
return self.current_control in self.search_links
@property
def search_target_buffer_control(self) -> Optional[BufferControl]:
"""
Return the :class:`.BufferControl` in which we are searching or `None`.
"""
# Not every `UIControl` is a `BufferControl`. This only applies to
# `BufferControl`.
control = self.current_control
if isinstance(control, SearchBufferControl):
return self.search_links.get(control)
else:
return None
def get_focusable_windows(self) -> Iterable[Window]:
"""
Return all the :class:`.Window` objects which are focusable (in the
'modal' area).
"""
for w in self.walk_through_modal_area():
if isinstance(w, Window) and w.content.is_focusable():
yield w
def get_visible_focusable_windows(self) -> List[Window]:
"""
Return a list of :class:`.Window` objects that are focusable.
"""
# focusable windows are windows that are visible, but also part of the
# modal container. Make sure to keep the ordering.
visible_windows = self.visible_windows
return [w for w in self.get_focusable_windows() if w in visible_windows]
@property
def current_buffer(self) -> Optional[Buffer]:
"""
The currently focused :class:`~.Buffer` or `None`.
"""
ui_control = self.current_control
if isinstance(ui_control, BufferControl):
return ui_control.buffer
return None
def get_buffer_by_name(self, buffer_name: str) -> Optional[Buffer]:
"""
Look in the layout for a buffer with the given name.
Return `None` when nothing was found.
"""
for w in self.walk():
if isinstance(w, Window) and isinstance(w.content, BufferControl):
if w.content.buffer.name == buffer_name:
return w.content.buffer
return None
@property
def buffer_has_focus(self) -> bool:
"""
Return `True` if the currently focused control is a
:class:`.BufferControl`. (For instance, used to determine whether the
default key bindings should be active or not.)
"""
ui_control = self.current_control
return isinstance(ui_control, BufferControl)
@property
def previous_control(self) -> UIControl:
"""
Get the :class:`.UIControl` to previously had the focus.
"""
try:
return self._stack[-2].content
except IndexError:
return self._stack[-1].content
def focus_last(self) -> None:
"""
Give the focus to the last focused control.
"""
if len(self._stack) > 1:
self._stack = self._stack[:-1]
def focus_next(self) -> None:
"""
Focus the next visible/focusable Window.
"""
windows = self.get_visible_focusable_windows()
if len(windows) > 0:
try:
index = windows.index(self.current_window)
except ValueError:
index = 0
else:
index = (index + 1) % len(windows)
self.focus(windows[index])
def focus_previous(self) -> None:
"""
Focus the previous visible/focusable Window.
"""
windows = self.get_visible_focusable_windows()
if len(windows) > 0:
try:
index = windows.index(self.current_window)
except ValueError:
index = 0
else:
index = (index - 1) % len(windows)
self.focus(windows[index])
def walk(self) -> Iterable[Container]:
"""
Walk through all the layout nodes (and their children) and yield them.
"""
for i in walk(self.container):
yield i
def walk_through_modal_area(self) -> Iterable[Container]:
"""
Walk through all the containers which are in the current 'modal' part
of the layout.
"""
# Go up in the tree, and find the root. (it will be a part of the
# layout, if the focus is in a modal part.)
root: Container = self.current_window
while not root.is_modal() and root in self._child_to_parent:
root = self._child_to_parent[root]
for container in walk(root):
yield container
def update_parents_relations(self) -> None:
"""
Update child->parent relationships mapping.
"""
parents = {}
def walk(e: Container) -> None:
for c in e.get_children():
parents[c] = e
walk(c)
walk(self.container)
self._child_to_parent = parents
def reset(self) -> None:
# Remove all search links when the UI starts.
# (Important, for instance when control-c is been pressed while
# searching. The prompt cancels, but next `run()` call the search
# links are still there.)
self.search_links.clear()
self.container.reset()
def get_parent(self, container: Container) -> Optional[Container]:
"""
Return the parent container for the given container, or ``None``, if it
wasn't found.
"""
try:
return self._child_to_parent[container]
except KeyError:
return None
class InvalidLayoutError(Exception):
pass
def walk(container: Container, skip_hidden: bool = False) -> Iterable[Container]:
"""
Walk through layout, starting at this container.
"""
# When `skip_hidden` is set, don't go into disabled ConditionalContainer containers.
if (
skip_hidden
and isinstance(container, ConditionalContainer)
and not container.filter()
):
return
yield container
for c in container.get_children():
# yield from walk(c)
yield from walk(c, skip_hidden=skip_hidden)