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denoland-deno/core/isolate.rs
2019-03-15 21:57:22 +01:00

559 lines
15 KiB
Rust

// Copyright 2018 the Deno authors. All rights reserved. MIT license.
use crate::js_errors::JSError;
use crate::libdeno;
use crate::libdeno::deno_buf;
use crate::libdeno::deno_mod;
use crate::shared_queue::SharedQueue;
use crate::shared_queue::RECOMMENDED_SIZE;
use futures::Async;
use futures::Future;
use futures::Poll;
use libc::c_void;
use std::ffi::CStr;
use std::ffi::CString;
use std::sync::{Once, ONCE_INIT};
pub type Buf = Box<[u8]>;
pub type Op = dyn Future<Item = Buf, Error = ()> + Send;
struct PendingOp {
op: Box<Op>,
polled_recently: bool,
zero_copy_id: usize, // non-zero if associated zero-copy buffer.
}
impl Future for PendingOp {
type Item = Buf;
type Error = ();
fn poll(&mut self) -> Poll<Buf, ()> {
// Do not call poll on ops we've already polled this turn.
if self.polled_recently {
Ok(Async::NotReady)
} else {
self.polled_recently = true;
let op = &mut self.op;
op.poll().map_err(|()| {
// Ops should not error. If an op experiences an error it needs to
// encode that error into a buf, so it can be returned to JS.
panic!("ops should not error")
})
}
}
}
/// Defines the behavior of an Isolate.
pub trait Behavior {
/// Called exactly once when an Isolate is created to retrieve the startup
/// snapshot.
fn startup_snapshot(&mut self) -> Option<deno_buf>;
/// Called during mod_instantiate() to resolve imports.
fn resolve(&mut self, specifier: &str, referrer: deno_mod) -> deno_mod;
/// Called whenever libdeno.send() is called in JavaScript. zero_copy_buf
/// corresponds to the second argument of libdeno.send().
fn dispatch(
&mut self,
control: &[u8],
zero_copy_buf: deno_buf,
) -> (bool, Box<Op>);
}
/// A single execution context of JavaScript. Corresponds roughly to the "Web
/// Worker" concept in the DOM. An Isolate is a Future that can be used with
/// Tokio. The Isolate future complete when there is an error or when all
/// pending ops have completed.
///
/// Ops are created in JavaScript by calling libdeno.send(), and in Rust by
/// implementing Behavior::dispatch. An Op corresponds exactly to a Promise in
/// JavaScript.
pub struct Isolate<B: Behavior> {
libdeno_isolate: *const libdeno::isolate,
behavior: B,
shared: SharedQueue,
pending_ops: Vec<PendingOp>,
polled_recently: bool,
}
unsafe impl<B: Behavior> Send for Isolate<B> {}
impl<B: Behavior> Drop for Isolate<B> {
fn drop(&mut self) {
unsafe { libdeno::deno_delete(self.libdeno_isolate) }
}
}
static DENO_INIT: Once = ONCE_INIT;
impl<B: Behavior> Isolate<B> {
pub fn new(mut behavior: B) -> Self {
DENO_INIT.call_once(|| {
unsafe { libdeno::deno_init() };
});
let shared = SharedQueue::new(RECOMMENDED_SIZE);
let config = libdeno::deno_config {
will_snapshot: 0,
load_snapshot: match behavior.startup_snapshot() {
Some(s) => s,
None => libdeno::deno_buf::empty(),
},
shared: shared.as_deno_buf(),
recv_cb: Self::pre_dispatch,
};
let libdeno_isolate = unsafe { libdeno::deno_new(config) };
Self {
libdeno_isolate,
behavior,
shared,
pending_ops: Vec::new(),
polled_recently: false,
}
}
/// Executes a bit of built-in JavaScript to provide Deno._sharedQueue.
pub fn shared_init(&self) {
js_check(self.execute("shared_queue.js", include_str!("shared_queue.js")));
}
extern "C" fn pre_dispatch(
user_data: *mut c_void,
control_argv0: deno_buf,
zero_copy_buf: deno_buf,
) {
let isolate = unsafe { Isolate::<B>::from_raw_ptr(user_data) };
let zero_copy_id = zero_copy_buf.zero_copy_id;
let control_shared = isolate.shared.shift();
let (is_sync, op) = if control_argv0.len() > 0 {
// The user called libdeno.send(control)
isolate
.behavior
.dispatch(control_argv0.as_ref(), zero_copy_buf)
} else if let Some(c) = control_shared {
// The user called Deno._sharedQueue.push(control)
isolate.behavior.dispatch(&c, zero_copy_buf)
} else {
// The sharedQueue is empty. The shouldn't happen usually, but it's also
// not technically a failure.
#[cfg(test)]
unreachable!();
#[cfg(not(test))]
return;
};
// At this point the SharedQueue should be empty.
assert_eq!(isolate.shared.size(), 0);
if is_sync {
let res_record = op.wait().unwrap();
let push_success = isolate.shared.push(res_record);
assert!(push_success);
// TODO check that if JSError thrown during respond(), that it will be
// picked up.
let _ = isolate.respond();
} else {
isolate.pending_ops.push(PendingOp {
op,
polled_recently: false,
zero_copy_id,
});
isolate.polled_recently = false;
}
}
fn zero_copy_release(&self, zero_copy_id: usize) {
unsafe {
libdeno::deno_zero_copy_release(self.libdeno_isolate, zero_copy_id)
}
}
#[inline]
unsafe fn from_raw_ptr<'a>(ptr: *const c_void) -> &'a mut Self {
let ptr = ptr as *mut _;
&mut *ptr
}
#[inline]
fn as_raw_ptr(&self) -> *const c_void {
self as *const _ as *const c_void
}
pub fn execute(
&self,
js_filename: &str,
js_source: &str,
) -> Result<(), JSError> {
let filename = CString::new(js_filename).unwrap();
let source = CString::new(js_source).unwrap();
unsafe {
libdeno::deno_execute(
self.libdeno_isolate,
self.as_raw_ptr(),
filename.as_ptr(),
source.as_ptr(),
)
};
if let Some(err) = self.last_exception() {
return Err(err);
}
Ok(())
}
fn last_exception(&self) -> Option<JSError> {
let ptr = unsafe { libdeno::deno_last_exception(self.libdeno_isolate) };
if ptr.is_null() {
None
} else {
let cstr = unsafe { CStr::from_ptr(ptr) };
let v8_exception = cstr.to_str().unwrap();
debug!("v8_exception\n{}\n", v8_exception);
let js_error = JSError::from_v8_exception(v8_exception).unwrap();
Some(js_error)
}
}
fn check_promise_errors(&self) {
unsafe {
libdeno::deno_check_promise_errors(self.libdeno_isolate);
}
}
fn respond(&mut self) -> Result<(), JSError> {
let buf = deno_buf::empty();
unsafe {
libdeno::deno_respond(self.libdeno_isolate, self.as_raw_ptr(), buf)
}
if let Some(err) = self.last_exception() {
Err(err)
} else {
Ok(())
}
}
/// Low-level module creation.
/// You probably want to use IsolateState::mod_execute instead.
pub fn mod_new(
&self,
main: bool,
name: &str,
source: &str,
) -> Result<deno_mod, JSError> {
let name_ = CString::new(name.to_string()).unwrap();
let name_ptr = name_.as_ptr() as *const libc::c_char;
let source_ = CString::new(source.to_string()).unwrap();
let source_ptr = source_.as_ptr() as *const libc::c_char;
let id = unsafe {
libdeno::deno_mod_new(self.libdeno_isolate, main, name_ptr, source_ptr)
};
if let Some(js_error) = self.last_exception() {
assert_eq!(id, 0);
return Err(js_error);
}
Ok(id)
}
pub fn mod_get_imports(&self, id: deno_mod) -> Vec<String> {
let len =
unsafe { libdeno::deno_mod_imports_len(self.libdeno_isolate, id) };
let mut out = Vec::new();
for i in 0..len {
let specifier_ptr =
unsafe { libdeno::deno_mod_imports_get(self.libdeno_isolate, id, i) };
let specifier_c: &CStr = unsafe { CStr::from_ptr(specifier_ptr) };
let specifier: &str = specifier_c.to_str().unwrap();
out.push(specifier.to_string());
}
out
}
pub fn mod_instantiate(&self, id: deno_mod) -> Result<(), JSError> {
unsafe {
libdeno::deno_mod_instantiate(
self.libdeno_isolate,
self.as_raw_ptr(),
id,
Self::resolve_cb,
)
};
if let Some(js_error) = self.last_exception() {
return Err(js_error);
}
Ok(())
}
pub fn mod_evaluate(&self, id: deno_mod) -> Result<(), JSError> {
unsafe {
libdeno::deno_mod_evaluate(self.libdeno_isolate, self.as_raw_ptr(), id)
};
if let Some(js_error) = self.last_exception() {
return Err(js_error);
}
Ok(())
}
/// Called during mod_instantiate() only.
extern "C" fn resolve_cb(
user_data: *mut libc::c_void,
specifier_ptr: *const libc::c_char,
referrer: deno_mod,
) -> deno_mod {
let isolate = unsafe { Isolate::<B>::from_raw_ptr(user_data) };
let specifier_c: &CStr = unsafe { CStr::from_ptr(specifier_ptr) };
let specifier: &str = specifier_c.to_str().unwrap();
isolate.behavior.resolve(specifier, referrer)
}
}
struct LockerScope {
libdeno_isolate: *const libdeno::isolate,
}
impl LockerScope {
fn new(libdeno_isolate: *const libdeno::isolate) -> LockerScope {
unsafe { libdeno::deno_lock(libdeno_isolate) }
LockerScope { libdeno_isolate }
}
}
impl Drop for LockerScope {
fn drop(&mut self) {
unsafe { libdeno::deno_unlock(self.libdeno_isolate) }
}
}
impl<B: Behavior> Future for Isolate<B> {
type Item = ();
type Error = JSError;
fn poll(&mut self) -> Poll<(), JSError> {
// Lock the current thread for V8.
let _locker = LockerScope::new(self.libdeno_isolate);
// Clear poll_recently state both on the Isolate itself and
// on the pending ops.
self.polled_recently = false;
for pending in self.pending_ops.iter_mut() {
pending.polled_recently = false;
}
while !self.polled_recently {
let mut completed_count = 0;
self.polled_recently = true;
assert_eq!(self.shared.size(), 0);
let mut i = 0;
while i < self.pending_ops.len() {
let pending = &mut self.pending_ops[i];
match pending.poll() {
Err(()) => panic!("unexpected error"),
Ok(Async::NotReady) => {
i += 1;
}
Ok(Async::Ready(buf)) => {
let completed = self.pending_ops.remove(i);
completed_count += 1;
if completed.zero_copy_id > 0 {
self.zero_copy_release(completed.zero_copy_id);
}
self.shared.push(buf);
}
}
}
if completed_count > 0 {
self.respond()?;
// The other side should have shifted off all the messages.
assert_eq!(self.shared.size(), 0);
}
}
self.check_promise_errors();
if let Some(err) = self.last_exception() {
return Err(err);
}
// We're idle if pending_ops is empty.
if self.pending_ops.is_empty() {
Ok(futures::Async::Ready(()))
} else {
Ok(futures::Async::NotReady)
}
}
}
pub fn js_check(r: Result<(), JSError>) {
if let Err(e) = r {
panic!(e.to_string());
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::test_util::*;
#[test]
fn test_dispatch() {
let behavior = TestBehavior::new();
let isolate = Isolate::new(behavior);
js_check(isolate.execute(
"filename.js",
r#"
let control = new Uint8Array([42]);
libdeno.send(control);
async function main() {
libdeno.send(control);
}
main();
"#,
));
assert_eq!(isolate.behavior.dispatch_count, 2);
}
#[test]
fn test_mods() {
let behavior = TestBehavior::new();
let mut isolate = Isolate::new(behavior);
let mod_a = isolate
.mod_new(
true,
"a.js",
r#"
import { b } from 'b.js'
if (b() != 'b') throw Error();
let control = new Uint8Array([42]);
libdeno.send(control);
"#,
).unwrap();
assert_eq!(isolate.behavior.dispatch_count, 0);
assert_eq!(isolate.behavior.resolve_count, 0);
let imports = isolate.mod_get_imports(mod_a);
assert_eq!(imports, vec!["b.js".to_string()]);
let mod_b = isolate
.mod_new(false, "b.js", "export function b() { return 'b' }")
.unwrap();
let imports = isolate.mod_get_imports(mod_b);
assert_eq!(imports.len(), 0);
js_check(isolate.mod_instantiate(mod_b));
assert_eq!(isolate.behavior.dispatch_count, 0);
assert_eq!(isolate.behavior.resolve_count, 0);
isolate.behavior.register("b.js", mod_b);
js_check(isolate.mod_instantiate(mod_a));
assert_eq!(isolate.behavior.dispatch_count, 0);
assert_eq!(isolate.behavior.resolve_count, 1);
js_check(isolate.mod_evaluate(mod_a));
assert_eq!(isolate.behavior.dispatch_count, 1);
assert_eq!(isolate.behavior.resolve_count, 1);
}
#[test]
fn test_poll_async_immediate_ops() {
let behavior = TestBehavior::new();
let mut isolate = Isolate::new(behavior);
isolate.shared_init();
js_check(isolate.execute(
"setup.js",
r#"
let nrecv = 0;
Deno._setAsyncHandler((buf) => {
nrecv++;
});
function assertEq(actual, expected) {
if (expected != actual) {
throw Error(`actual ${actual} expected ${expected} `);
}
}
"#,
));
assert_eq!(isolate.behavior.dispatch_count, 0);
js_check(isolate.execute(
"check1.js",
r#"
assertEq(nrecv, 0);
let control = new Uint8Array([42]);
libdeno.send(control);
assertEq(nrecv, 0);
"#,
));
assert_eq!(isolate.behavior.dispatch_count, 1);
assert_eq!(Ok(Async::Ready(())), isolate.poll());
assert_eq!(isolate.behavior.dispatch_count, 1);
js_check(isolate.execute(
"check2.js",
r#"
assertEq(nrecv, 1);
libdeno.send(control);
assertEq(nrecv, 1);
"#,
));
assert_eq!(isolate.behavior.dispatch_count, 2);
assert_eq!(Ok(Async::Ready(())), isolate.poll());
js_check(isolate.execute("check3.js", "assertEq(nrecv, 2)"));
assert_eq!(isolate.behavior.dispatch_count, 2);
// We are idle, so the next poll should be the last.
assert_eq!(Ok(Async::Ready(())), isolate.poll());
}
#[test]
fn test_shared() {
let behavior = TestBehavior::new();
let mut isolate = Isolate::new(behavior);
isolate.shared_init();
js_check(isolate.execute(
"setup.js",
r#"
let nrecv = 0;
Deno._setAsyncHandler((buf) => {
assert(buf.byteLength === 1);
assert(buf[0] === 43);
nrecv++;
});
function assert(cond) {
if (!cond) {
throw Error("assert");
}
}
"#,
));
assert_eq!(isolate.behavior.dispatch_count, 0);
js_check(isolate.execute(
"send1.js",
r#"
let control = new Uint8Array([42]);
Deno._sharedQueue.push(control);
libdeno.send();
assert(nrecv === 0);
Deno._sharedQueue.push(control);
libdeno.send();
assert(nrecv === 0);
"#,
));
assert_eq!(isolate.behavior.dispatch_count, 2);
assert_eq!(Ok(Async::Ready(())), isolate.poll());
js_check(isolate.execute("send1.js", "assert(nrecv === 2);"));
}
}