deno/core/inspector.rs

748 lines
24 KiB
Rust

// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
//! The documentation for the inspector API is sparse, but these are helpful:
//! <https://chromedevtools.github.io/devtools-protocol/>
//! <https://hyperandroid.com/2020/02/12/v8-inspector-from-an-embedder-standpoint/>
use crate::error::generic_error;
use crate::futures::channel::mpsc;
use crate::futures::channel::mpsc::UnboundedReceiver;
use crate::futures::channel::mpsc::UnboundedSender;
use crate::futures::channel::oneshot;
use crate::futures::future::select;
use crate::futures::future::Either;
use crate::futures::future::Future;
use crate::futures::prelude::*;
use crate::futures::stream::SelectAll;
use crate::futures::stream::StreamExt;
use crate::futures::task;
use crate::futures::task::Context;
use crate::futures::task::Poll;
use crate::serde_json;
use crate::serde_json::json;
use crate::serde_json::Value;
use anyhow::Error;
use parking_lot::Mutex;
use std::cell::BorrowMutError;
use std::cell::RefCell;
use std::collections::HashMap;
use std::ffi::c_void;
use std::mem::take;
use std::mem::MaybeUninit;
use std::pin::Pin;
use std::ptr;
use std::ptr::NonNull;
use std::rc::Rc;
use std::sync::Arc;
use std::thread;
pub enum InspectorMsgKind {
Notification,
Message(i32),
}
pub struct InspectorMsg {
pub kind: InspectorMsgKind,
pub content: String,
}
pub type SessionProxySender = UnboundedSender<InspectorMsg>;
pub type SessionProxyReceiver = UnboundedReceiver<String>;
/// Encapsulates an UnboundedSender/UnboundedReceiver pair that together form
/// a duplex channel for sending/receiving messages in V8 session.
pub struct InspectorSessionProxy {
pub tx: SessionProxySender,
pub rx: SessionProxyReceiver,
}
#[derive(Clone, Copy)]
enum PollState {
Idle,
Woken,
Polling,
Parked,
Dropped,
}
/// This structure is used responsible for providing inspector interface
/// to the `JsRuntime`.
///
/// It stores an instance of `v8::inspector::V8Inspector` and additionally
/// implements `v8::inspector::V8InspectorClientImpl`.
///
/// After creating this structure it's possible to connect multiple sessions
/// to the inspector, in case of Deno it's either: a "websocket session" that
/// provides integration with Chrome Devtools, or an "in-memory session" that
/// is used for REPL or converage collection.
pub struct JsRuntimeInspector {
v8_inspector_client: v8::inspector::V8InspectorClientBase,
v8_inspector: Rc<RefCell<v8::UniquePtr<v8::inspector::V8Inspector>>>,
new_session_tx: UnboundedSender<InspectorSessionProxy>,
sessions: RefCell<SessionContainer>,
flags: RefCell<InspectorFlags>,
waker: Arc<InspectorWaker>,
deregister_tx: Option<oneshot::Sender<()>>,
}
impl Drop for JsRuntimeInspector {
fn drop(&mut self) {
// Since the waker is cloneable, it might outlive the inspector itself.
// Set the poll state to 'dropped' so it doesn't attempt to request an
// interrupt from the isolate.
self.waker.update(|w| w.poll_state = PollState::Dropped);
// V8 automatically deletes all sessions when an `V8Inspector` instance is
// deleted, however InspectorSession also has a drop handler that cleans
// up after itself. To avoid a double free, make sure the inspector is
// dropped last.
self.sessions.borrow_mut().drop_sessions();
// Notify counterparty that this instance is being destroyed. Ignoring
// result because counterparty waiting for the signal might have already
// dropped the other end of channel.
if let Some(deregister_tx) = self.deregister_tx.take() {
let _ = deregister_tx.send(());
}
}
}
impl v8::inspector::V8InspectorClientImpl for JsRuntimeInspector {
fn base(&self) -> &v8::inspector::V8InspectorClientBase {
&self.v8_inspector_client
}
fn base_mut(&mut self) -> &mut v8::inspector::V8InspectorClientBase {
&mut self.v8_inspector_client
}
fn run_message_loop_on_pause(&mut self, context_group_id: i32) {
assert_eq!(context_group_id, JsRuntimeInspector::CONTEXT_GROUP_ID);
self.flags.borrow_mut().on_pause = true;
let _ = self.poll_sessions(None);
}
fn quit_message_loop_on_pause(&mut self) {
self.flags.borrow_mut().on_pause = false;
}
fn run_if_waiting_for_debugger(&mut self, context_group_id: i32) {
assert_eq!(context_group_id, JsRuntimeInspector::CONTEXT_GROUP_ID);
self.flags.borrow_mut().waiting_for_session = false;
}
}
/// Polling `JsRuntimeInspector` allows inspector to accept new incoming
/// connections and "pump" messages in different sessions.
///
/// It should be polled on tick of event loop, ie. in `JsRuntime::poll_event_loop`
/// function.
impl Future for JsRuntimeInspector {
type Output = ();
fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<()> {
self.poll_sessions(Some(cx)).unwrap()
}
}
impl JsRuntimeInspector {
/// Currently Deno supports only a single context in `JsRuntime`
/// and thus it's id is provided as an associated contant.
const CONTEXT_GROUP_ID: i32 = 1;
pub fn new(
isolate: &mut v8::OwnedIsolate,
context: v8::Global<v8::Context>,
) -> Rc<RefCell<Self>> {
let scope = &mut v8::HandleScope::new(isolate);
let (new_session_tx, new_session_rx) =
mpsc::unbounded::<InspectorSessionProxy>();
let v8_inspector_client =
v8::inspector::V8InspectorClientBase::new::<Self>();
let waker = InspectorWaker::new(scope.thread_safe_handle());
// Create JsRuntimeInspector instance.
let self__ = Rc::new(RefCell::new(Self {
v8_inspector_client,
v8_inspector: Default::default(),
sessions: RefCell::new(SessionContainer::temporary_placeholder()),
new_session_tx,
flags: Default::default(),
waker,
deregister_tx: None,
}));
let mut self_ = self__.borrow_mut();
self_.v8_inspector = Rc::new(RefCell::new(
v8::inspector::V8Inspector::create(scope, &mut *self_).into(),
));
self_.sessions = RefCell::new(SessionContainer::new(
self_.v8_inspector.clone(),
new_session_rx,
));
// Tell the inspector about the global context.
let context = v8::Local::new(scope, context);
let context_name = v8::inspector::StringView::from(&b"global context"[..]);
self_
.v8_inspector
.borrow_mut()
.as_mut()
.unwrap()
.context_created(context, Self::CONTEXT_GROUP_ID, context_name);
// Poll the session handler so we will get notified whenever there is
// new incoming debugger activity.
let _ = self_.poll_sessions(None).unwrap();
drop(self_);
self__
}
pub fn has_active_sessions(&self) -> bool {
self.sessions.borrow().has_active_sessions()
}
fn poll_sessions(
&self,
mut invoker_cx: Option<&mut Context>,
) -> Result<Poll<()>, BorrowMutError> {
// The futures this function uses do not have re-entrant poll() functions.
// However it is can happpen that poll_sessions() gets re-entered, e.g.
// when an interrupt request is honored while the inspector future is polled
// by the task executor. We let the caller know by returning some error.
let mut sessions = self.sessions.try_borrow_mut()?;
self.waker.update(|w| {
match w.poll_state {
PollState::Idle | PollState::Woken => w.poll_state = PollState::Polling,
_ => unreachable!(),
};
});
// Create a new Context object that will make downstream futures
// use the InspectorWaker when they are ready to be polled again.
let waker_ref = task::waker_ref(&self.waker);
let cx = &mut Context::from_waker(&waker_ref);
loop {
loop {
// Do one "handshake" with a newly connected session at a time.
if let Some(mut session) = sessions.handshake.take() {
let poll_result = session.poll_next_unpin(cx);
match poll_result {
Poll::Pending => {
sessions.established.push(session);
continue;
}
Poll::Ready(Some(session_stream_item)) => {
let (v8_session_ptr, msg) = session_stream_item;
InspectorSession::dispatch_message(v8_session_ptr, msg);
sessions.established.push(session);
continue;
}
Poll::Ready(None) => {}
}
}
// Accept new connections.
let poll_result = sessions.session_rx.poll_next_unpin(cx);
if let Poll::Ready(Some(session_proxy)) = poll_result {
let session =
InspectorSession::new(sessions.v8_inspector.clone(), session_proxy);
let prev = sessions.handshake.replace(session);
assert!(prev.is_none());
}
// Poll established sessions.
match sessions.established.poll_next_unpin(cx) {
Poll::Ready(Some(session_stream_item)) => {
let (v8_session_ptr, msg) = session_stream_item;
InspectorSession::dispatch_message(v8_session_ptr, msg);
continue;
}
Poll::Ready(None) => break,
Poll::Pending => break,
};
}
let should_block =
self.flags.borrow().on_pause || self.flags.borrow().waiting_for_session;
let new_state = self.waker.update(|w| {
match w.poll_state {
PollState::Woken => {
// The inspector was woken while the session handler was being
// polled, so we poll it another time.
w.poll_state = PollState::Polling;
}
PollState::Polling if !should_block => {
// The session handler doesn't need to be polled any longer, and
// there's no reason to block (execution is not paused), so this
// function is about to return.
w.poll_state = PollState::Idle;
// Register the task waker that can be used to wake the parent
// task that will poll the inspector future.
if let Some(cx) = invoker_cx.take() {
w.task_waker.replace(cx.waker().clone());
}
// Register the address of the inspector, which allows the waker
// to request an interrupt from the isolate.
w.inspector_ptr = NonNull::new(self as *const _ as *mut Self);
}
PollState::Polling if should_block => {
// Isolate execution has been paused but there are no more
// events to process, so this thread will be parked. Therefore,
// store the current thread handle in the waker so it knows
// which thread to unpark when new events arrive.
w.poll_state = PollState::Parked;
w.parked_thread.replace(thread::current());
}
_ => unreachable!(),
};
w.poll_state
});
match new_state {
PollState::Idle => break Ok(Poll::Pending), // Yield to task.
PollState::Polling => {} // Poll the session handler again.
PollState::Parked => thread::park(), // Park the thread.
_ => unreachable!(),
};
}
}
/// This function blocks the thread until at least one inspector client has
/// established a websocket connection.
///
/// After that, it instructs V8 to pause at the next statement.
/// Frontend must send "Runtime.runIfWaitingForDebugger" message to resume
/// execution.
pub fn wait_for_session_and_break_on_next_statement(&mut self) {
loop {
match self.sessions.get_mut().established.iter_mut().next() {
Some(session) => break session.break_on_next_statement(),
None => {
self.flags.get_mut().waiting_for_session = true;
let _ = self.poll_sessions(None).unwrap();
}
};
}
}
/// Obtain a sender for proxy channels.
pub fn get_session_sender(&self) -> UnboundedSender<InspectorSessionProxy> {
self.new_session_tx.clone()
}
/// Create a channel that notifies the frontend when inspector is dropped.
///
/// NOTE: Only a single handler is currently available.
pub fn add_deregister_handler(&mut self) -> oneshot::Receiver<()> {
let (tx, rx) = oneshot::channel::<()>();
let prev = self.deregister_tx.replace(tx);
assert!(
prev.is_none(),
"Only a single deregister handler is allowed"
);
rx
}
/// Create a local inspector session that can be used on
/// the same thread as the isolate.
pub fn create_local_session(&self) -> LocalInspectorSession {
// The 'outbound' channel carries messages sent to the session.
let (outbound_tx, outbound_rx) = mpsc::unbounded();
// The 'inbound' channel carries messages received from the session.
let (inbound_tx, inbound_rx) = mpsc::unbounded();
let proxy = InspectorSessionProxy {
tx: outbound_tx,
rx: inbound_rx,
};
// InspectorSessions for a local session is added directly to the "established"
// sessions, so it doesn't need to go through the session sender.
let inspector_session =
InspectorSession::new(self.v8_inspector.clone(), proxy);
self
.sessions
.borrow_mut()
.established
.push(inspector_session);
take(&mut self.flags.borrow_mut().waiting_for_session);
LocalInspectorSession::new(inbound_tx, outbound_rx)
}
}
#[derive(Default)]
struct InspectorFlags {
waiting_for_session: bool,
on_pause: bool,
}
/// A helper structure that helps coordinate sessions during different
/// parts of their lifecycle.
struct SessionContainer {
v8_inspector: Rc<RefCell<v8::UniquePtr<v8::inspector::V8Inspector>>>,
session_rx: UnboundedReceiver<InspectorSessionProxy>,
handshake: Option<Box<InspectorSession>>,
established: SelectAll<Box<InspectorSession>>,
}
impl SessionContainer {
fn new(
v8_inspector: Rc<RefCell<v8::UniquePtr<v8::inspector::V8Inspector>>>,
new_session_rx: UnboundedReceiver<InspectorSessionProxy>,
) -> Self {
Self {
v8_inspector,
session_rx: new_session_rx,
handshake: None,
established: SelectAll::new(),
}
}
/// V8 automatically deletes all sessions when an `V8Inspector` instance is
/// deleted, however InspectorSession also has a drop handler that cleans
/// up after itself. To avoid a double free, we need to manually drop
/// all sessions before dropping the inspector instance.
fn drop_sessions(&mut self) {
self.v8_inspector = Default::default();
self.handshake.take();
self.established.clear();
}
fn has_active_sessions(&self) -> bool {
!self.established.is_empty() || self.handshake.is_some()
}
/// A temporary placeholder that should be used before actual
/// instance of V8Inspector is created. It's used in favor
/// of `Default` implementation to signal that it's not meant
/// for actual use.
fn temporary_placeholder() -> Self {
let (_tx, rx) = mpsc::unbounded::<InspectorSessionProxy>();
Self {
v8_inspector: Default::default(),
session_rx: rx,
handshake: None,
established: SelectAll::new(),
}
}
}
struct InspectorWakerInner {
poll_state: PollState,
task_waker: Option<task::Waker>,
parked_thread: Option<thread::Thread>,
inspector_ptr: Option<NonNull<JsRuntimeInspector>>,
isolate_handle: v8::IsolateHandle,
}
// SAFETY: unsafe trait must have unsafe implementation
unsafe impl Send for InspectorWakerInner {}
struct InspectorWaker(Mutex<InspectorWakerInner>);
impl InspectorWaker {
fn new(isolate_handle: v8::IsolateHandle) -> Arc<Self> {
let inner = InspectorWakerInner {
poll_state: PollState::Idle,
task_waker: None,
parked_thread: None,
inspector_ptr: None,
isolate_handle,
};
Arc::new(Self(Mutex::new(inner)))
}
fn update<F, R>(&self, update_fn: F) -> R
where
F: FnOnce(&mut InspectorWakerInner) -> R,
{
let mut g = self.0.lock();
update_fn(&mut g)
}
}
impl task::ArcWake for InspectorWaker {
fn wake_by_ref(arc_self: &Arc<Self>) {
arc_self.update(|w| {
match w.poll_state {
PollState::Idle => {
// Wake the task, if any, that has polled the Inspector future last.
if let Some(waker) = w.task_waker.take() {
waker.wake()
}
// Request an interrupt from the isolate if it's running and there's
// not unhandled interrupt request in flight.
if let Some(arg) = w
.inspector_ptr
.take()
.map(|ptr| ptr.as_ptr() as *mut c_void)
{
w.isolate_handle.request_interrupt(handle_interrupt, arg);
}
extern "C" fn handle_interrupt(
_isolate: &mut v8::Isolate,
arg: *mut c_void,
) {
// SAFETY: `InspectorWaker` is owned by `JsRuntimeInspector`, so the
// pointer to the latter is valid as long as waker is alive.
let inspector = unsafe { &*(arg as *mut JsRuntimeInspector) };
let _ = inspector.poll_sessions(None);
}
}
PollState::Parked => {
// Unpark the isolate thread.
let parked_thread = w.parked_thread.take().unwrap();
assert_ne!(parked_thread.id(), thread::current().id());
parked_thread.unpark();
}
_ => {}
};
w.poll_state = PollState::Woken;
});
}
}
/// An inspector session that proxies messages to concrete "transport layer",
/// eg. Websocket or another set of channels.
struct InspectorSession {
v8_channel: v8::inspector::ChannelBase,
v8_session: v8::UniqueRef<v8::inspector::V8InspectorSession>,
proxy: InspectorSessionProxy,
}
impl InspectorSession {
const CONTEXT_GROUP_ID: i32 = 1;
pub fn new(
v8_inspector_rc: Rc<RefCell<v8::UniquePtr<v8::inspector::V8Inspector>>>,
session_proxy: InspectorSessionProxy,
) -> Box<Self> {
new_box_with(move |self_ptr| {
let v8_channel = v8::inspector::ChannelBase::new::<Self>();
let mut v8_inspector = v8_inspector_rc.borrow_mut();
let v8_inspector_ptr = v8_inspector.as_mut().unwrap();
// TODO(piscisaureus): safety comment
#[allow(clippy::undocumented_unsafe_blocks)]
let v8_session = v8_inspector_ptr.connect(
Self::CONTEXT_GROUP_ID,
// Todo(piscisaureus): V8Inspector::connect() should require that
// the 'v8_channel' argument cannot move.
unsafe { &mut *self_ptr },
v8::inspector::StringView::empty(),
v8::inspector::V8InspectorClientTrustLevel::FullyTrusted,
);
Self {
v8_channel,
v8_session,
proxy: session_proxy,
}
})
}
// Dispatch message to V8 session
fn dispatch_message(
v8_session_ptr: *mut v8::inspector::V8InspectorSession,
msg: String,
) {
let msg = v8::inspector::StringView::from(msg.as_bytes());
// SAFETY: `InspectorSession` is the only owner of `v8_session_ptr`, so
// the pointer is valid for as long the struct.
unsafe {
(*v8_session_ptr).dispatch_protocol_message(msg);
};
}
fn send_message(
&self,
msg_kind: InspectorMsgKind,
msg: v8::UniquePtr<v8::inspector::StringBuffer>,
) {
let msg = msg.unwrap().string().to_string();
let _ = self.proxy.tx.unbounded_send(InspectorMsg {
kind: msg_kind,
content: msg,
});
}
pub fn break_on_next_statement(&mut self) {
let reason = v8::inspector::StringView::from(&b"debugCommand"[..]);
let detail = v8::inspector::StringView::empty();
// TODO(bartlomieju): use raw `*mut V8InspectorSession` pointer, as this
// reference may become aliased.
(*self.v8_session).schedule_pause_on_next_statement(reason, detail);
}
}
impl v8::inspector::ChannelImpl for InspectorSession {
fn base(&self) -> &v8::inspector::ChannelBase {
&self.v8_channel
}
fn base_mut(&mut self) -> &mut v8::inspector::ChannelBase {
&mut self.v8_channel
}
fn send_response(
&mut self,
call_id: i32,
message: v8::UniquePtr<v8::inspector::StringBuffer>,
) {
self.send_message(InspectorMsgKind::Message(call_id), message);
}
fn send_notification(
&mut self,
message: v8::UniquePtr<v8::inspector::StringBuffer>,
) {
self.send_message(InspectorMsgKind::Notification, message);
}
fn flush_protocol_notifications(&mut self) {}
}
impl Stream for InspectorSession {
type Item = (*mut v8::inspector::V8InspectorSession, String);
fn poll_next(
self: Pin<&mut Self>,
cx: &mut Context,
) -> Poll<Option<Self::Item>> {
let inner = self.get_mut();
if let Poll::Ready(maybe_msg) = inner.proxy.rx.poll_next_unpin(cx) {
if let Some(msg) = maybe_msg {
return Poll::Ready(Some((&mut *inner.v8_session, msg)));
} else {
return Poll::Ready(None);
}
}
Poll::Pending
}
}
/// A local inspector session that can be used to send and receive protocol messages directly on
/// the same thread as an isolate.
pub struct LocalInspectorSession {
v8_session_tx: UnboundedSender<String>,
v8_session_rx: UnboundedReceiver<InspectorMsg>,
response_tx_map: HashMap<i32, oneshot::Sender<serde_json::Value>>,
next_message_id: i32,
notification_queue: Vec<Value>,
}
impl LocalInspectorSession {
pub fn new(
v8_session_tx: UnboundedSender<String>,
v8_session_rx: UnboundedReceiver<InspectorMsg>,
) -> Self {
let response_tx_map = HashMap::new();
let next_message_id = 0;
let notification_queue = Vec::new();
Self {
v8_session_tx,
v8_session_rx,
response_tx_map,
next_message_id,
notification_queue,
}
}
pub fn notifications(&mut self) -> Vec<Value> {
self.notification_queue.split_off(0)
}
pub async fn post_message<T: serde::Serialize>(
&mut self,
method: &str,
params: Option<T>,
) -> Result<serde_json::Value, Error> {
let id = self.next_message_id;
self.next_message_id += 1;
let (response_tx, mut response_rx) =
oneshot::channel::<serde_json::Value>();
self.response_tx_map.insert(id, response_tx);
let message = json!({
"id": id,
"method": method,
"params": params,
});
let stringified_msg = serde_json::to_string(&message).unwrap();
self.v8_session_tx.unbounded_send(stringified_msg).unwrap();
loop {
let receive_fut = self.receive_from_v8_session().boxed_local();
match select(receive_fut, &mut response_rx).await {
Either::Left(_) => continue,
Either::Right((result, _)) => {
let response = result?;
if let Some(error) = response.get("error") {
return Err(generic_error(error.to_string()));
}
let result = response.get("result").unwrap().clone();
return Ok(result);
}
}
}
}
async fn receive_from_v8_session(&mut self) {
let inspector_msg = self.v8_session_rx.next().await.unwrap();
if let InspectorMsgKind::Message(msg_id) = inspector_msg.kind {
let message: serde_json::Value =
match serde_json::from_str(&inspector_msg.content) {
Ok(v) => v,
Err(error) => match error.classify() {
serde_json::error::Category::Syntax => json!({
"id": msg_id,
"result": {
"result": {
"type": "error",
"description": "Unterminated string literal",
"value": "Unterminated string literal",
},
"exceptionDetails": {
"exceptionId": 0,
"text": "Unterminated string literal",
"lineNumber": 0,
"columnNumber": 0
},
},
}),
_ => panic!("Could not parse inspector message"),
},
};
self
.response_tx_map
.remove(&msg_id)
.unwrap()
.send(message)
.unwrap();
} else {
let message = serde_json::from_str(&inspector_msg.content).unwrap();
self.notification_queue.push(message);
}
}
}
fn new_box_with<T>(new_fn: impl FnOnce(*mut T) -> T) -> Box<T> {
let b = Box::new(MaybeUninit::<T>::uninit());
let p = Box::into_raw(b) as *mut T;
// SAFETY: memory layout for `T` is ensured on first line of this function
unsafe {
ptr::write(p, new_fn(p));
Box::from_raw(p)
}
}