""" Key bindings registry. A `KeyBindings` object is a container that holds a list of key bindings. It has a very efficient internal data structure for checking which key bindings apply for a pressed key. Typical usage:: kb = KeyBindings() @kb.add(Keys.ControlX, Keys.ControlC, filter=INSERT) def handler(event): # Handle ControlX-ControlC key sequence. pass It is also possible to combine multiple KeyBindings objects. We do this in the default key bindings. There are some KeyBindings objects that contain the Emacs bindings, while others contain the Vi bindings. They are merged together using `merge_key_bindings`. We also have a `ConditionalKeyBindings` object that can enable/disable a group of key bindings at once. It is also possible to add a filter to a function, before a key binding has been assigned, through the `key_binding` decorator.:: # First define a key handler with the `filter`. @key_binding(filter=condition) def my_key_binding(event): ... # Later, add it to the key bindings. kb.add(Keys.A, my_key_binding) """ from abc import ABCMeta, abstractmethod, abstractproperty from inspect import isawaitable from typing import ( TYPE_CHECKING, Awaitable, Callable, Hashable, List, Optional, Sequence, Tuple, TypeVar, Union, cast, ) from prompt_toolkit.cache import SimpleCache from prompt_toolkit.filters import FilterOrBool, Never, to_filter from prompt_toolkit.keys import KEY_ALIASES, Keys if TYPE_CHECKING: # Avoid circular imports. from .key_processor import KeyPressEvent # The only two return values for a mouse hander (and key bindings) are # `None` and `NotImplemented`. For the type checker it's best to annotate # this as `object`. (The consumer never expects a more specific instance: # checking for NotImplemented can be done using `is NotImplemented`.) NotImplementedOrNone = object # Other non-working options are: # * Optional[Literal[NotImplemented]] # --> Doesn't work, Literal can't take an Any. # * None # --> Doesn't work. We can't assign the result of a function that # returns `None` to a variable. # * Any # --> Works, but too broad. __all__ = [ "NotImplementedOrNone", "Binding", "KeyBindingsBase", "KeyBindings", "ConditionalKeyBindings", "merge_key_bindings", "DynamicKeyBindings", "GlobalOnlyKeyBindings", ] # Key bindings can be regular functions or coroutines. # In both cases, if they return `NotImplemented`, the UI won't be invalidated. # This is mainly used in case of mouse move events, to prevent excessive # repainting during mouse move events. KeyHandlerCallable = Callable[ ["KeyPressEvent"], Union["NotImplementedOrNone", Awaitable["NotImplementedOrNone"]] ] class Binding: """ Key binding: (key sequence + handler + filter). (Immutable binding class.) :param record_in_macro: When True, don't record this key binding when a macro is recorded. """ def __init__( self, keys: Tuple[Union[Keys, str], ...], handler: KeyHandlerCallable, filter: FilterOrBool = True, eager: FilterOrBool = False, is_global: FilterOrBool = False, save_before: Callable[["KeyPressEvent"], bool] = (lambda e: True), record_in_macro: FilterOrBool = True, ) -> None: self.keys = keys self.handler = handler self.filter = to_filter(filter) self.eager = to_filter(eager) self.is_global = to_filter(is_global) self.save_before = save_before self.record_in_macro = to_filter(record_in_macro) def call(self, event: "KeyPressEvent") -> None: result = self.handler(event) # If the handler is a coroutine, create an asyncio task. if isawaitable(result): awaitable = cast(Awaitable["NotImplementedOrNone"], result) async def bg_task() -> None: result = await awaitable if result != NotImplemented: event.app.invalidate() event.app.create_background_task(bg_task()) elif result != NotImplemented: event.app.invalidate() def __repr__(self) -> str: return "{}(keys={!r}, handler={!r})".format( self.__class__.__name__, self.keys, self.handler, ) # Sequence of keys presses. KeysTuple = Tuple[Union[Keys, str], ...] class KeyBindingsBase(metaclass=ABCMeta): """ Interface for a KeyBindings. """ @abstractproperty def _version(self) -> Hashable: """ For cache invalidation. - This should increase every time that something changes. """ return 0 @abstractmethod def get_bindings_for_keys(self, keys: KeysTuple) -> List[Binding]: """ Return a list of key bindings that can handle these keys. (This return also inactive bindings, so the `filter` still has to be called, for checking it.) :param keys: tuple of keys. """ return [] @abstractmethod def get_bindings_starting_with_keys(self, keys: KeysTuple) -> List[Binding]: """ Return a list of key bindings that handle a key sequence starting with `keys`. (It does only return bindings for which the sequences are longer than `keys`. And like `get_bindings_for_keys`, it also includes inactive bindings.) :param keys: tuple of keys. """ return [] @abstractproperty def bindings(self) -> List[Binding]: """ List of `Binding` objects. (These need to be exposed, so that `KeyBindings` objects can be merged together.) """ return [] # `add` and `remove` don't have to be part of this interface. T = TypeVar("T", bound=Union[KeyHandlerCallable, Binding]) class KeyBindings(KeyBindingsBase): """ A container for a set of key bindings. Example usage:: kb = KeyBindings() @kb.add('c-t') def _(event): print('Control-T pressed') @kb.add('c-a', 'c-b') def _(event): print('Control-A pressed, followed by Control-B') @kb.add('c-x', filter=is_searching) def _(event): print('Control-X pressed') # Works only if we are searching. """ def __init__(self) -> None: self._bindings: List[Binding] = [] self._get_bindings_for_keys_cache: SimpleCache[ KeysTuple, List[Binding] ] = SimpleCache(maxsize=10000) self._get_bindings_starting_with_keys_cache: SimpleCache[ KeysTuple, List[Binding] ] = SimpleCache(maxsize=1000) self.__version = 0 # For cache invalidation. def _clear_cache(self) -> None: self.__version += 1 self._get_bindings_for_keys_cache.clear() self._get_bindings_starting_with_keys_cache.clear() @property def bindings(self) -> List[Binding]: return self._bindings @property def _version(self) -> Hashable: return self.__version def add( self, *keys: Union[Keys, str], filter: FilterOrBool = True, eager: FilterOrBool = False, is_global: FilterOrBool = False, save_before: Callable[["KeyPressEvent"], bool] = (lambda e: True), record_in_macro: FilterOrBool = True, ) -> Callable[[T], T]: """ Decorator for adding a key bindings. :param filter: :class:`~prompt_toolkit.filters.Filter` to determine when this key binding is active. :param eager: :class:`~prompt_toolkit.filters.Filter` or `bool`. When True, ignore potential longer matches when this key binding is hit. E.g. when there is an active eager key binding for Ctrl-X, execute the handler immediately and ignore the key binding for Ctrl-X Ctrl-E of which it is a prefix. :param is_global: When this key bindings is added to a `Container` or `Control`, make it a global (always active) binding. :param save_before: Callable that takes an `Event` and returns True if we should save the current buffer, before handling the event. (That's the default.) :param record_in_macro: Record these key bindings when a macro is being recorded. (True by default.) """ assert keys keys = tuple(_parse_key(k) for k in keys) if isinstance(filter, Never): # When a filter is Never, it will always stay disabled, so in that # case don't bother putting it in the key bindings. It will slow # down every key press otherwise. def decorator(func: T) -> T: return func else: def decorator(func: T) -> T: if isinstance(func, Binding): # We're adding an existing Binding object. self.bindings.append( Binding( keys, func.handler, filter=func.filter & to_filter(filter), eager=to_filter(eager) | func.eager, is_global=to_filter(is_global) | func.is_global, save_before=func.save_before, record_in_macro=func.record_in_macro, ) ) else: self.bindings.append( Binding( keys, cast(KeyHandlerCallable, func), filter=filter, eager=eager, is_global=is_global, save_before=save_before, record_in_macro=record_in_macro, ) ) self._clear_cache() return func return decorator def remove(self, *args: Union[Keys, str, KeyHandlerCallable]) -> None: """ Remove a key binding. This expects either a function that was given to `add` method as parameter or a sequence of key bindings. Raises `ValueError` when no bindings was found. Usage:: remove(handler) # Pass handler. remove('c-x', 'c-a') # Or pass the key bindings. """ found = False if callable(args[0]): assert len(args) == 1 function = args[0] # Remove the given function. for b in self.bindings: if b.handler == function: self.bindings.remove(b) found = True else: assert len(args) > 0 args = cast(Tuple[Union[Keys, str]], args) # Remove this sequence of key bindings. keys = tuple(_parse_key(k) for k in args) for b in self.bindings: if b.keys == keys: self.bindings.remove(b) found = True if found: self._clear_cache() else: # No key binding found for this function. Raise ValueError. raise ValueError(f"Binding not found: {function!r}") # For backwards-compatibility. add_binding = add remove_binding = remove def get_bindings_for_keys(self, keys: KeysTuple) -> List[Binding]: """ Return a list of key bindings that can handle this key. (This return also inactive bindings, so the `filter` still has to be called, for checking it.) :param keys: tuple of keys. """ def get() -> List[Binding]: result: List[Tuple[int, Binding]] = [] for b in self.bindings: if len(keys) == len(b.keys): match = True any_count = 0 for i, j in zip(b.keys, keys): if i != j and i != Keys.Any: match = False break if i == Keys.Any: any_count += 1 if match: result.append((any_count, b)) # Place bindings that have more 'Any' occurrences in them at the end. result = sorted(result, key=lambda item: -item[0]) return [item[1] for item in result] return self._get_bindings_for_keys_cache.get(keys, get) def get_bindings_starting_with_keys(self, keys: KeysTuple) -> List[Binding]: """ Return a list of key bindings that handle a key sequence starting with `keys`. (It does only return bindings for which the sequences are longer than `keys`. And like `get_bindings_for_keys`, it also includes inactive bindings.) :param keys: tuple of keys. """ def get() -> List[Binding]: result = [] for b in self.bindings: if len(keys) < len(b.keys): match = True for i, j in zip(b.keys, keys): if i != j and i != Keys.Any: match = False break if match: result.append(b) return result return self._get_bindings_starting_with_keys_cache.get(keys, get) def _parse_key(key: Union[Keys, str]) -> Union[str, Keys]: """ Replace key by alias and verify whether it's a valid one. """ # Already a parse key? -> Return it. if isinstance(key, Keys): return key # Lookup aliases. key = KEY_ALIASES.get(key, key) # Replace 'space' by ' ' if key == "space": key = " " # Return as `Key` object when it's a special key. try: return Keys(key) except ValueError: pass # Final validation. if len(key) != 1: raise ValueError(f"Invalid key: {key}") return key def key_binding( filter: FilterOrBool = True, eager: FilterOrBool = False, is_global: FilterOrBool = False, save_before: Callable[["KeyPressEvent"], bool] = (lambda event: True), record_in_macro: FilterOrBool = True, ) -> Callable[[KeyHandlerCallable], Binding]: """ Decorator that turn a function into a `Binding` object. This can be added to a `KeyBindings` object when a key binding is assigned. """ assert save_before is None or callable(save_before) filter = to_filter(filter) eager = to_filter(eager) is_global = to_filter(is_global) save_before = save_before record_in_macro = to_filter(record_in_macro) keys = () def decorator(function: KeyHandlerCallable) -> Binding: return Binding( keys, function, filter=filter, eager=eager, is_global=is_global, save_before=save_before, record_in_macro=record_in_macro, ) return decorator class _Proxy(KeyBindingsBase): """ Common part for ConditionalKeyBindings and _MergedKeyBindings. """ def __init__(self) -> None: # `KeyBindings` to be synchronized with all the others. self._bindings2: KeyBindingsBase = KeyBindings() self._last_version: Hashable = () def _update_cache(self) -> None: """ If `self._last_version` is outdated, then this should update the version and `self._bindings2`. """ raise NotImplementedError # Proxy methods to self._bindings2. @property def bindings(self) -> List[Binding]: self._update_cache() return self._bindings2.bindings @property def _version(self) -> Hashable: self._update_cache() return self._last_version def get_bindings_for_keys(self, keys: KeysTuple) -> List[Binding]: self._update_cache() return self._bindings2.get_bindings_for_keys(keys) def get_bindings_starting_with_keys(self, keys: KeysTuple) -> List[Binding]: self._update_cache() return self._bindings2.get_bindings_starting_with_keys(keys) class ConditionalKeyBindings(_Proxy): """ Wraps around a `KeyBindings`. Disable/enable all the key bindings according to the given (additional) filter.:: @Condition def setting_is_true(): return True # or False registry = ConditionalKeyBindings(key_bindings, setting_is_true) When new key bindings are added to this object. They are also enable/disabled according to the given `filter`. :param registries: List of :class:`.KeyBindings` objects. :param filter: :class:`~prompt_toolkit.filters.Filter` object. """ def __init__( self, key_bindings: KeyBindingsBase, filter: FilterOrBool = True ) -> None: _Proxy.__init__(self) self.key_bindings = key_bindings self.filter = to_filter(filter) def _update_cache(self) -> None: "If the original key bindings was changed. Update our copy version." expected_version = self.key_bindings._version if self._last_version != expected_version: bindings2 = KeyBindings() # Copy all bindings from `self.key_bindings`, adding our condition. for b in self.key_bindings.bindings: bindings2.bindings.append( Binding( keys=b.keys, handler=b.handler, filter=self.filter & b.filter, eager=b.eager, is_global=b.is_global, save_before=b.save_before, record_in_macro=b.record_in_macro, ) ) self._bindings2 = bindings2 self._last_version = expected_version class _MergedKeyBindings(_Proxy): """ Merge multiple registries of key bindings into one. This class acts as a proxy to multiple :class:`.KeyBindings` objects, but behaves as if this is just one bigger :class:`.KeyBindings`. :param registries: List of :class:`.KeyBindings` objects. """ def __init__(self, registries: Sequence[KeyBindingsBase]) -> None: _Proxy.__init__(self) self.registries = registries def _update_cache(self) -> None: """ If one of the original registries was changed. Update our merged version. """ expected_version = tuple(r._version for r in self.registries) if self._last_version != expected_version: bindings2 = KeyBindings() for reg in self.registries: bindings2.bindings.extend(reg.bindings) self._bindings2 = bindings2 self._last_version = expected_version def merge_key_bindings(bindings: Sequence[KeyBindingsBase]) -> _MergedKeyBindings: """ Merge multiple :class:`.Keybinding` objects together. Usage:: bindings = merge_key_bindings([bindings1, bindings2, ...]) """ return _MergedKeyBindings(bindings) class DynamicKeyBindings(_Proxy): """ KeyBindings class that can dynamically returns any KeyBindings. :param get_key_bindings: Callable that returns a :class:`.KeyBindings` instance. """ def __init__( self, get_key_bindings: Callable[[], Optional[KeyBindingsBase]] ) -> None: self.get_key_bindings = get_key_bindings self.__version = 0 self._last_child_version = None self._dummy = KeyBindings() # Empty key bindings. def _update_cache(self) -> None: key_bindings = self.get_key_bindings() or self._dummy assert isinstance(key_bindings, KeyBindingsBase) version = id(key_bindings), key_bindings._version self._bindings2 = key_bindings self._last_version = version class GlobalOnlyKeyBindings(_Proxy): """ Wrapper around a :class:`.KeyBindings` object that only exposes the global key bindings. """ def __init__(self, key_bindings: KeyBindingsBase) -> None: _Proxy.__init__(self) self.key_bindings = key_bindings def _update_cache(self) -> None: """ If one of the original registries was changed. Update our merged version. """ expected_version = self.key_bindings._version if self._last_version != expected_version: bindings2 = KeyBindings() for b in self.key_bindings.bindings: if b.is_global(): bindings2.bindings.append(b) self._bindings2 = bindings2 self._last_version = expected_version