# Copyright (c) Microsoft Corporation. All rights reserved. # Licensed under the MIT License. See LICENSE in the project root # for license information. import functools from debugpy.common import json, log, messaging, util ACCEPT_CONNECTIONS_TIMEOUT = 10 class ComponentNotAvailable(Exception): def __init__(self, type): super().__init__(f"{type.__name__} is not available") class Component(util.Observable): """A component managed by a debug adapter: client, launcher, or debug server. Every component belongs to a Session, which is used for synchronization and shared data. Every component has its own message channel, and provides message handlers for that channel. All handlers should be decorated with @Component.message_handler, which ensures that Session is locked for the duration of the handler. Thus, only one handler is running at any given time across all components, unless the lock is released explicitly or via Session.wait_for(). Components report changes to their attributes to Session, allowing one component to wait_for() a change caused by another component. """ def __init__(self, session, stream=None, channel=None): assert (stream is None) ^ (channel is None) try: lock_held = session.lock.acquire(blocking=False) assert lock_held, "__init__ of a Component subclass must lock its Session" finally: session.lock.release() super().__init__() self.session = session if channel is None: stream.name = str(self) channel = messaging.JsonMessageChannel(stream, self) channel.start() else: channel.name = channel.stream.name = str(self) channel.handlers = self self.channel = channel self.is_connected = True # Do this last to avoid triggering useless notifications for assignments above. self.observers += [lambda *_: self.session.notify_changed()] def __str__(self): return f"{type(self).__name__}[{self.session.id}]" @property def client(self): return self.session.client @property def launcher(self): return self.session.launcher @property def server(self): return self.session.server def wait_for(self, *args, **kwargs): return self.session.wait_for(*args, **kwargs) @staticmethod def message_handler(f): """Applied to a message handler to automatically lock and unlock the session for its duration, and to validate the session state. If the handler raises ComponentNotAvailable or JsonIOError, converts it to Message.cant_handle(). """ @functools.wraps(f) def lock_and_handle(self, message): try: with self.session: return f(self, message) except ComponentNotAvailable as exc: raise message.cant_handle("{0}", exc, silent=True) except messaging.MessageHandlingError as exc: if exc.cause is message: raise else: exc.propagate(message) except messaging.JsonIOError as exc: raise message.cant_handle( "{0} disconnected unexpectedly", exc.stream.name, silent=True ) return lock_and_handle def disconnect(self): with self.session: self.is_connected = False self.session.finalize("{0} has disconnected".format(self)) def missing(session, type): class Missing(object): """A dummy component that raises ComponentNotAvailable whenever some attribute is accessed on it. """ __getattr__ = __setattr__ = lambda self, *_: report() __bool__ = __nonzero__ = lambda self: False def report(): try: raise ComponentNotAvailable(type) except Exception as exc: log.reraise_exception("{0} in {1}", exc, session) return Missing() class Capabilities(dict): """A collection of feature flags for a component. Corresponds to JSON properties in the DAP "initialize" request or response, other than those that identify the party. """ PROPERTIES = {} """JSON property names and default values for the the capabilities represented by instances of this class. Keys are names, and values are either default values or validators. If the value is callable, it must be a JSON validator; see debugpy.common.json for details. If the value is not callable, it is as if json.default(value) validator was used instead. """ def __init__(self, component, message): """Parses an "initialize" request or response and extracts the feature flags. For every "X" in self.PROPERTIES, sets self["X"] to the corresponding value from message.payload if it's present there, or to the default value otherwise. """ assert message.is_request("initialize") or message.is_response("initialize") self.component = component payload = message.payload for name, validate in self.PROPERTIES.items(): value = payload.get(name, ()) if not callable(validate): validate = json.default(validate) try: value = validate(value) except Exception as exc: raise message.isnt_valid("{0} {1}", json.repr(name), exc) assert ( value != () ), f"{validate} must provide a default value for missing properties." self[name] = value log.debug("{0}", self) def __repr__(self): return f"{type(self).__name__}: {json.repr(dict(self))}" def require(self, *keys): for key in keys: if not self[key]: raise messaging.MessageHandlingError( f"{self.component} does not have capability {json.repr(key)}", )