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ops.rs
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ops.rs
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// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
use crate::error::type_error;
use crate::error::AnyError;
use crate::gotham_state::GothamState;
use crate::ops_metrics::OpsTracker;
use crate::resources::ResourceTable;
use crate::runtime::GetErrorClassFn;
use futures::future::maybe_done;
use futures::future::FusedFuture;
use futures::future::MaybeDone;
use futures::ready;
use futures::task::noop_waker;
use futures::Future;
use indexmap::IndexMap;
use serde::de::DeserializeOwned;
use serde::Serialize;
use std::cell::RefCell;
use std::iter::once;
use std::ops::Deref;
use std::ops::DerefMut;
use std::pin::Pin;
use std::rc::Rc;
use std::task::Context;
use std::task::Poll;
/// Wrapper around a Future, which causes that Future to be polled immediately.
/// (Background: ops are stored in a `FuturesUnordered` structure which polls
/// them, but without the `OpCall` wrapper this doesn't happen until the next
/// turn of the event loop, which is too late for certain ops.)
pub struct OpCall<T>(MaybeDone<Pin<Box<dyn Future<Output = T>>>>);
impl<T> OpCall<T> {
/// Wraps a future, and polls the inner future immediately.
/// This should be the default choice for ops.
pub fn eager(fut: impl Future<Output = T> + 'static) -> Self {
let boxed = Box::pin(fut) as Pin<Box<dyn Future<Output = T>>>;
let mut inner = maybe_done(boxed);
let waker = noop_waker();
let mut cx = Context::from_waker(&waker);
let mut pinned = Pin::new(&mut inner);
let _ = pinned.as_mut().poll(&mut cx);
Self(inner)
}
/// Wraps a future; the inner future is polled the usual way (lazily).
pub fn lazy(fut: impl Future<Output = T> + 'static) -> Self {
let boxed = Box::pin(fut) as Pin<Box<dyn Future<Output = T>>>;
let inner = maybe_done(boxed);
Self(inner)
}
/// Create a future by specifying its output. This is basically the same as
/// `async { value }` or `futures::future::ready(value)`.
pub fn ready(value: T) -> Self {
Self(MaybeDone::Done(value))
}
}
impl<T> Future for OpCall<T> {
type Output = T;
fn poll(
self: std::pin::Pin<&mut Self>,
cx: &mut std::task::Context<'_>,
) -> std::task::Poll<Self::Output> {
let inner = unsafe { &mut self.get_unchecked_mut().0 };
let mut pinned = Pin::new(inner);
ready!(pinned.as_mut().poll(cx));
Poll::Ready(pinned.as_mut().take_output().unwrap())
}
}
impl<F> FusedFuture for OpCall<F>
where
F: Future,
{
fn is_terminated(&self) -> bool {
self.0.is_terminated()
}
}
pub type PromiseId = u64;
pub type OpAsyncFuture = OpCall<(PromiseId, OpId, OpResult)>;
pub type OpFn = dyn Fn(Rc<RefCell<OpState>>, OpPayload) -> Op + 'static;
pub type OpId = usize;
pub struct OpPayload<'a, 'b, 'c> {
pub(crate) scope: &'a mut v8::HandleScope<'b>,
pub(crate) a: v8::Local<'c, v8::Value>,
pub(crate) b: v8::Local<'c, v8::Value>,
pub(crate) op_id: OpId,
pub(crate) promise_id: PromiseId,
}
impl<'a, 'b, 'c> OpPayload<'a, 'b, 'c> {
pub fn deserialize<T: DeserializeOwned, U: DeserializeOwned>(
self,
) -> Result<(T, U), AnyError> {
let a: T = serde_v8::from_v8(self.scope, self.a)
.map_err(AnyError::from)
.map_err(|e| type_error(format!("Error parsing args: {}", e)))?;
let b: U = serde_v8::from_v8(self.scope, self.b)
.map_err(AnyError::from)
.map_err(|e| type_error(format!("Error parsing args: {}", e)))?;
Ok((a, b))
}
}
pub enum Op {
Sync(OpResult),
Async(OpAsyncFuture),
/// AsyncUnref is the variation of Async, which doesn't block the program
/// exiting.
AsyncUnref(OpAsyncFuture),
NotFound,
}
pub enum OpResult {
Ok(serde_v8::SerializablePkg),
Err(OpError),
}
impl OpResult {
pub fn to_v8<'a>(
&self,
scope: &mut v8::HandleScope<'a>,
) -> Result<v8::Local<'a, v8::Value>, serde_v8::Error> {
match self {
Self::Ok(x) => x.to_v8(scope),
Self::Err(err) => serde_v8::to_v8(scope, err),
}
}
}
#[derive(Serialize)]
#[serde(rename_all = "camelCase")]
pub struct OpError {
#[serde(rename = "$err_class_name")]
class_name: &'static str,
message: String,
code: Option<&'static str>,
}
pub fn serialize_op_result<R: Serialize + 'static>(
result: Result<R, AnyError>,
state: Rc<RefCell<OpState>>,
) -> OpResult {
match result {
Ok(v) => OpResult::Ok(v.into()),
Err(err) => OpResult::Err(OpError {
class_name: (state.borrow().get_error_class_fn)(&err),
message: err.to_string(),
code: crate::error_codes::get_error_code(&err),
}),
}
}
/// Maintains the resources and ops inside a JS runtime.
pub struct OpState {
pub resource_table: ResourceTable,
pub op_table: OpTable,
pub get_error_class_fn: GetErrorClassFn,
pub(crate) tracker: OpsTracker,
gotham_state: GothamState,
}
impl OpState {
pub(crate) fn new() -> OpState {
OpState {
resource_table: Default::default(),
op_table: OpTable::default(),
get_error_class_fn: &|_| "Error",
tracker: OpsTracker {
ops: RefCell::new(Vec::with_capacity(256)),
},
gotham_state: Default::default(),
}
}
}
impl Deref for OpState {
type Target = GothamState;
fn deref(&self) -> &Self::Target {
&self.gotham_state
}
}
impl DerefMut for OpState {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.gotham_state
}
}
/// Collection for storing registered ops. The special 'get_op_catalog'
/// op with OpId `0` is automatically added when the OpTable is created.
pub struct OpTable(IndexMap<String, Rc<OpFn>>);
impl OpTable {
pub fn register_op<F>(&mut self, name: &str, op_fn: F) -> OpId
where
F: Fn(Rc<RefCell<OpState>>, OpPayload) -> Op + 'static,
{
let (op_id, prev) = self.0.insert_full(name.to_owned(), Rc::new(op_fn));
assert!(prev.is_none());
op_id
}
pub fn op_entries(state: Rc<RefCell<OpState>>) -> Vec<(String, OpId)> {
state.borrow().op_table.0.keys().cloned().zip(0..).collect()
}
pub fn route_op(
op_id: OpId,
state: Rc<RefCell<OpState>>,
payload: OpPayload,
) -> Op {
let op_fn = state
.borrow()
.op_table
.0
.get_index(op_id)
.map(|(_, op_fn)| op_fn.clone());
match op_fn {
Some(f) => (f)(state, payload),
None => Op::NotFound,
}
}
}
impl Default for OpTable {
fn default() -> Self {
fn dummy(_state: Rc<RefCell<OpState>>, _p: OpPayload) -> Op {
unreachable!()
}
Self(once(("ops".to_owned(), Rc::new(dummy) as _)).collect())
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn op_table() {
let state = Rc::new(RefCell::new(OpState::new()));
let foo_id;
let bar_id;
{
let op_table = &mut state.borrow_mut().op_table;
foo_id =
op_table.register_op("foo", |_, _| Op::Sync(OpResult::Ok(321.into())));
assert_eq!(foo_id, 1);
bar_id =
op_table.register_op("bar", |_, _| Op::Sync(OpResult::Ok(123.into())));
assert_eq!(bar_id, 2);
}
let mut catalog_entries = OpTable::op_entries(state);
catalog_entries.sort_by(|(_, id1), (_, id2)| id1.partial_cmp(id2).unwrap());
assert_eq!(
catalog_entries,
vec![
("ops".to_owned(), 0),
("foo".to_owned(), 1),
("bar".to_owned(), 2)
]
);
}
}