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denoland-deno/core/inspector.rs
Bartek Iwańczuk e5beb800c9
refactor: move JsRuntimeInspector to deno_core (#10763)
This commit moves implementation of "JsRuntimeInspector" to "deno_core" crate.

To achieve that following changes were made:

* "Worker" and "WebWorker" no longer own instance of "JsRuntimeInspector",
instead it is now owned by "deno_core::JsRuntime".

* Consequently polling of inspector is no longer done in "Worker"/"WebWorker",
instead it's done in "deno_core::JsRuntime::poll_event_loop".

* "deno_core::JsRuntime::poll_event_loop" and "deno_core::JsRuntime::run_event_loop",
now accept "wait_for_inspector" boolean that tells if event loop should still be 
"pending" if there are active inspector sessions - this change fixes the problem 
that inspector disconnects from the frontend and process exits once the code has
stopped executing.
2021-05-26 21:07:12 +02:00

755 lines
24 KiB
Rust

// Copyright 2018-2021 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::error::AnyError;
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::FuturesUnordered;
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 crate::v8;
use std::cell::BorrowMutError;
use std::cell::RefCell;
use std::collections::HashMap;
use std::ffi::c_void;
use std::mem::replace;
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::sync::Mutex;
use std::thread;
/// If first argument is `None` then it's a notification, otherwise
/// it's a message.
pub type SessionProxySender = UnboundedSender<(Option<i32>, String)>;
// TODO(bartlomieju): does it even need to send a Result?
// It seems `Vec<u8>` would be enough
pub type SessionProxyReceiver = UnboundedReceiver<Result<Vec<u8>, AnyError>>;
/// 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,
}
impl InspectorSessionProxy {
pub fn split(self) -> (SessionProxySender, SessionProxyReceiver) {
(self.tx, self.rx)
}
}
#[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);
// TODO(bartlomieju): this comment is out of date
// 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.
take(&mut *self.sessions.borrow_mut());
// 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().session_handshake_done = true;
}
}
/// `JsRuntimeInspector` implements a Future so that it can poll for new incoming
/// connections and messages from the WebSocket server. The Worker that owns
/// this `JsRuntimeInspector` will call this function from `Worker::poll()`.
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>,
) -> Box<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 flags = InspectorFlags::new();
let waker = InspectorWaker::new(scope.thread_safe_handle());
// Create JsRuntimeInspector instance.
let mut self_ = Box::new(Self {
v8_inspector_client,
v8_inspector: Default::default(),
sessions: Default::default(),
new_session_tx,
flags,
waker,
deregister_tx: None,
});
self_.v8_inspector = Rc::new(RefCell::new(
v8::inspector::V8Inspector::create(scope, &mut *self_).into(),
));
self_.sessions =
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();
self_
}
pub fn has_active_sessions(&self) -> bool {
let sessions = self.sessions.borrow();
!sessions.established.is_empty() || sessions.handshake.is_some()
}
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(session) = &mut sessions.handshake {
let poll_result = session.poll_unpin(cx);
let handshake_done =
replace(&mut self.flags.borrow_mut().session_handshake_done, false);
match poll_result {
Poll::Pending if handshake_done => {
let session = sessions.handshake.take().unwrap();
sessions.established.push(session);
take(&mut self.flags.borrow_mut().waiting_for_session);
}
Poll::Ready(_) => sessions.handshake = None,
Poll::Pending => break,
};
}
// Accept new connections.
match sessions.new_incoming.poll_next_unpin(cx) {
Poll::Ready(Some(session)) => {
let prev = sessions.handshake.replace(session);
assert!(prev.is_none());
continue;
}
Poll::Ready(None) => {}
Poll::Pending => {}
}
// Poll established sessions.
match sessions.established.poll_next_unpin(cx) {
Poll::Ready(Some(_)) => continue,
Poll::Ready(None) => break,
Poll::Pending => break,
};
}
let should_block = sessions.handshake.is_some()
|| 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 and successfully completed the
/// handshake. After that, it instructs V8 to pause at the next statement.
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.
///
/// After a proxy is sent inspector will wait for a "handshake".
/// Frontend must send "Runtime.runIfWaitingForDebugger" message to
/// complete the handshake.
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 and handshake
// phase.
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,
session_handshake_done: bool,
on_pause: bool,
}
impl InspectorFlags {
fn new() -> RefCell<Self> {
let self_ = Self::default();
RefCell::new(self_)
}
}
/// A helper structure that helps coordinate sessions during different
/// parts of their lifecycle.
struct SessionContainer {
new_incoming: Pin<Box<dyn Stream<Item = Box<InspectorSession>> + 'static>>,
handshake: Option<Box<InspectorSession>>,
established: FuturesUnordered<Box<InspectorSession>>,
}
impl SessionContainer {
fn new(
v8_inspector: Rc<RefCell<v8::UniquePtr<v8::inspector::V8Inspector>>>,
new_session_rx: UnboundedReceiver<InspectorSessionProxy>,
) -> RefCell<Self> {
let new_incoming = new_session_rx
.map(move |session_proxy| {
InspectorSession::new(v8_inspector.clone(), session_proxy)
})
.boxed_local();
let self_ = Self {
new_incoming,
..Default::default()
};
RefCell::new(self_)
}
}
impl Default for SessionContainer {
fn default() -> Self {
Self {
new_incoming: stream::empty().boxed_local(),
handshake: None,
established: FuturesUnordered::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,
}
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().unwrap();
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,
) {
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: Rc<RefCell<v8::UniqueRef<v8::inspector::V8InspectorSession>>>,
proxy_tx: SessionProxySender,
proxy_rx_handler: Pin<Box<dyn Future<Output = ()> + 'static>>,
}
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();
let v8_session = Rc::new(RefCell::new(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(),
)));
let (proxy_tx, proxy_rx) = session_proxy.split();
let proxy_rx_handler =
Self::receive_from_proxy(v8_session.clone(), proxy_rx);
Self {
v8_channel,
v8_session,
proxy_tx,
proxy_rx_handler,
}
})
}
// Dispatch message to V8 session
#[allow(unused)]
fn dispatch_message(&mut self, msg: Vec<u8>) {
let msg = v8::inspector::StringView::from(msg.as_slice());
let mut v8_session = self.v8_session.borrow_mut();
let v8_session_ptr = v8_session.as_mut();
v8_session_ptr.dispatch_protocol_message(msg);
}
// TODO(bartlomieju): this function should be reworked into `impl Future`
// or `impl Stream`
/// Returns a future that receives messages from the proxy and dispatches
/// them to the V8 session.
fn receive_from_proxy(
v8_session_rc: Rc<
RefCell<v8::UniqueRef<v8::inspector::V8InspectorSession>>,
>,
proxy_rx: SessionProxyReceiver,
) -> Pin<Box<dyn Future<Output = ()> + 'static>> {
async move {
let result = proxy_rx
.map_ok(move |msg| {
let msg = v8::inspector::StringView::from(msg.as_slice());
let mut v8_session = v8_session_rc.borrow_mut();
let v8_session_ptr = v8_session.as_mut();
v8_session_ptr.dispatch_protocol_message(msg);
})
.try_collect::<()>()
.await;
// TODO(bartlomieju): ideally these prints should be moved
// to `server.rs` as they are unwanted in context of REPL/coverage collection
// but right now they do not pose a huge problem. Investigate how to
// move them to `server.rs`.
match result {
Ok(_) => eprintln!("Debugger session ended."),
Err(err) => eprintln!("Debugger session ended: {}.", err),
};
}
.boxed_local()
}
fn send_message(
&self,
maybe_call_id: Option<i32>,
msg: v8::UniquePtr<v8::inspector::StringBuffer>,
) {
let msg = msg.unwrap().string().to_string();
let _ = self.proxy_tx.unbounded_send((maybe_call_id, msg));
}
pub fn break_on_next_statement(&mut self) {
let reason = v8::inspector::StringView::from(&b"debugCommand"[..]);
let detail = v8::inspector::StringView::empty();
self
.v8_session
.borrow_mut()
.as_mut()
.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(Some(call_id), message);
}
fn send_notification(
&mut self,
message: v8::UniquePtr<v8::inspector::StringBuffer>,
) {
self.send_message(None, message);
}
fn flush_protocol_notifications(&mut self) {}
}
impl Future for InspectorSession {
type Output = ();
fn poll(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
self.proxy_rx_handler.poll_unpin(cx)
}
}
/// 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<Result<Vec<u8>, AnyError>>,
v8_session_rx: UnboundedReceiver<(Option<i32>, String)>,
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<Result<Vec<u8>, AnyError>>,
v8_session_rx: UnboundedReceiver<(Option<i32>, String)>,
) -> 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(
&mut self,
method: &str,
params: Option<serde_json::Value>,
) -> Result<serde_json::Value, AnyError> {
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 raw_message = serde_json::to_string(&message).unwrap();
self
.v8_session_tx
.unbounded_send(Ok(raw_message.as_bytes().to_vec()))
.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 (maybe_call_id, message) = self.v8_session_rx.next().await.unwrap();
// If there's no call_id then it's a notification
if let Some(call_id) = maybe_call_id {
let message: serde_json::Value = match serde_json::from_str(&message) {
Ok(v) => v,
Err(error) => match error.classify() {
serde_json::error::Category::Syntax => json!({
"id": call_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(&call_id)
.unwrap()
.send(message)
.unwrap();
} else {
let message = serde_json::from_str(&message).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;
unsafe { ptr::write(p, new_fn(p)) };
unsafe { Box::from_raw(p) }
}