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denoland-deno/src/resources.rs

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// Copyright 2018 the Deno authors. All rights reserved. MIT license.
// Think of Resources as File Descriptors. They are integers that are allocated
// by the privlaged side of Deno to refer to various resources. The simplest
// example are standard file system files and stdio - but there will be other
// resources added in the future that might not correspond to operating system
// level File Descriptors. To avoid confusion we call them "resources" not "file
// descriptors". This module implements a global resource table. Ops (AKA
// handlers) look up resources by their integer id here.
use errors::DenoError;
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use tokio_util;
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use tokio_write;
use futures;
use futures::future::Either;
use futures::future::FutureResult;
use futures::Poll;
use std;
use std::collections::HashMap;
use std::io::Error;
use std::io::{Read, Write};
use std::net::{Shutdown, SocketAddr};
use std::sync::atomic::AtomicIsize;
use std::sync::atomic::Ordering;
use std::sync::Mutex;
use tokio;
use tokio::io::{AsyncRead, AsyncWrite};
use tokio::net::TcpStream;
use tokio_io;
pub type ResourceId = i32; // Sometimes referred to RID.
// These store Deno's file descriptors. These are not necessarily the operating
// system ones.
type ResourceTable = HashMap<ResourceId, Repr>;
lazy_static! {
// Starts at 3 because stdio is [0-2].
static ref NEXT_RID: AtomicIsize = AtomicIsize::new(3);
static ref RESOURCE_TABLE: Mutex<ResourceTable> = Mutex::new({
let mut m = HashMap::new();
// TODO Load these lazily during lookup?
m.insert(0, Repr::Stdin(tokio::io::stdin()));
m.insert(1, Repr::Stdout(tokio::io::stdout()));
m.insert(2, Repr::Stderr(tokio::io::stderr()));
m
});
}
// Internal representation of Resource.
enum Repr {
Stdin(tokio::io::Stdin),
Stdout(tokio::io::Stdout),
Stderr(tokio::io::Stderr),
FsFile(tokio::fs::File),
TcpListener(tokio::net::TcpListener),
TcpStream(tokio::net::TcpStream),
}
// Abstract async file interface.
// Ideally in unix, if Resource represents an OS rid, it will be the same.
#[derive(Debug)]
pub struct Resource {
pub rid: ResourceId,
}
impl Resource {
// TODO Should it return a Resource instead of net::TcpStream?
pub fn poll_accept(&mut self) -> Poll<(TcpStream, SocketAddr), Error> {
let mut table = RESOURCE_TABLE.lock().unwrap();
let maybe_repr = table.get_mut(&self.rid);
match maybe_repr {
None => panic!("bad rid"),
Some(repr) => match repr {
Repr::TcpListener(ref mut s) => s.poll_accept(),
_ => panic!("Cannot accept"),
},
}
}
// close(2) is done by dropping the value. Therefore we just need to remove
// the resource from the RESOURCE_TABLE.
pub fn close(&mut self) {
let mut table = RESOURCE_TABLE.lock().unwrap();
let r = table.remove(&self.rid);
assert!(r.is_some());
}
pub fn shutdown(&mut self, how: Shutdown) -> Result<(), DenoError> {
let mut table = RESOURCE_TABLE.lock().unwrap();
let maybe_repr = table.get_mut(&self.rid);
match maybe_repr {
None => panic!("bad rid"),
Some(repr) => match repr {
Repr::TcpStream(ref mut f) => {
TcpStream::shutdown(f, how).map_err(|err| DenoError::from(err))
}
_ => panic!("Cannot shutdown"),
},
}
}
}
impl Read for Resource {
fn read(&mut self, _buf: &mut [u8]) -> std::io::Result<usize> {
unimplemented!();
}
}
impl AsyncRead for Resource {
fn poll_read(&mut self, buf: &mut [u8]) -> Poll<usize, Error> {
let mut table = RESOURCE_TABLE.lock().unwrap();
let maybe_repr = table.get_mut(&self.rid);
match maybe_repr {
None => panic!("bad rid"),
Some(repr) => match repr {
Repr::FsFile(ref mut f) => f.poll_read(buf),
Repr::Stdin(ref mut f) => f.poll_read(buf),
Repr::TcpStream(ref mut f) => f.poll_read(buf),
Repr::Stdout(_) | Repr::Stderr(_) => {
panic!("Cannot read from stdout/stderr")
}
Repr::TcpListener(_) => panic!("Cannot read"),
},
}
}
}
impl Write for Resource {
fn write(&mut self, _buf: &[u8]) -> std::io::Result<usize> {
unimplemented!()
}
fn flush(&mut self) -> std::io::Result<()> {
unimplemented!()
}
}
impl AsyncWrite for Resource {
fn poll_write(&mut self, buf: &[u8]) -> Poll<usize, Error> {
let mut table = RESOURCE_TABLE.lock().unwrap();
let maybe_repr = table.get_mut(&self.rid);
match maybe_repr {
None => panic!("bad rid"),
Some(repr) => match repr {
Repr::FsFile(ref mut f) => f.poll_write(buf),
Repr::Stdout(ref mut f) => f.poll_write(buf),
Repr::Stderr(ref mut f) => f.poll_write(buf),
Repr::TcpStream(ref mut f) => f.poll_write(buf),
Repr::Stdin(_) => panic!("Cannot write to stdin"),
Repr::TcpListener(_) => panic!("Cannot write"),
},
}
}
fn shutdown(&mut self) -> futures::Poll<(), std::io::Error> {
unimplemented!()
}
}
fn new_rid() -> ResourceId {
let next_rid = NEXT_RID.fetch_add(1, Ordering::SeqCst);
next_rid as ResourceId
}
pub fn add_fs_file(fs_file: tokio::fs::File) -> Resource {
let rid = new_rid();
let mut tg = RESOURCE_TABLE.lock().unwrap();
match tg.insert(rid, Repr::FsFile(fs_file)) {
Some(_) => panic!("There is already a file with that rid"),
None => Resource { rid },
}
}
pub fn add_tcp_listener(listener: tokio::net::TcpListener) -> Resource {
let rid = new_rid();
let mut tg = RESOURCE_TABLE.lock().unwrap();
let r = tg.insert(rid, Repr::TcpListener(listener));
assert!(r.is_none());
Resource { rid }
}
pub fn add_tcp_stream(stream: tokio::net::TcpStream) -> Resource {
let rid = new_rid();
let mut tg = RESOURCE_TABLE.lock().unwrap();
let r = tg.insert(rid, Repr::TcpStream(stream));
assert!(r.is_none());
Resource { rid }
}
pub fn lookup(rid: ResourceId) -> Option<Resource> {
let table = RESOURCE_TABLE.lock().unwrap();
table.get(&rid).map(|_| Resource { rid })
}
type EagerRead<R, T> =
Either<tokio_io::io::Read<R, T>, FutureResult<(R, T, usize), std::io::Error>>;
#[cfg(windows)]
#[allow(unused_mut)]
pub fn eager_read<T>(resource: Resource, mut buf: T) -> EagerRead<Resource, T>
where
T: AsMut<[u8]>,
{
Either::A(tokio_io::io::read(resource, buf)).into()
}
// This is an optimization that Tokio should do.
// Attempt to call read() on the main thread.
#[cfg(not(windows))]
pub fn eager_read<T>(resource: Resource, mut buf: T) -> EagerRead<Resource, T>
where
T: AsMut<[u8]>,
{
let mut table = RESOURCE_TABLE.lock().unwrap();
let maybe_repr = table.get_mut(&resource.rid);
match maybe_repr {
None => panic!("bad rid"),
Some(repr) => match repr {
Repr::TcpStream(ref mut tcp_stream) => {
// Unforunately we can't just call read() on tokio::net::TcpStream
use std::os::unix::io::AsRawFd;
use std::os::unix::io::FromRawFd;
use std::os::unix::io::IntoRawFd;
let mut std_tcp_stream =
unsafe { std::net::TcpStream::from_raw_fd(tcp_stream.as_raw_fd()) };
let read_result = std_tcp_stream.read(buf.as_mut());
// std_tcp_stream will close when it gets dropped. Thus...
let _ = std_tcp_stream.into_raw_fd();
match read_result {
Ok(nread) => Either::B(futures::future::ok((resource, buf, nread))),
Err(err) => {
if err.kind() == std::io::ErrorKind::WouldBlock {
Either::A(tokio_io::io::read(resource, buf))
} else {
Either::B(futures::future::err(err))
}
}
}
}
_ => Either::A(tokio_io::io::read(resource, buf)),
},
}
}
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type EagerWrite<R, T> =
Either<tokio_write::Write<R, T>, FutureResult<(R, T, usize), std::io::Error>>;
#[cfg(windows)]
pub fn eager_write<T>(resource: Resource, buf: T) -> EagerWrite<Resource, T>
where
T: AsRef<[u8]>,
{
Either::A(tokio_write::write(resource, buf)).into()
}
// This is an optimization that Tokio should do.
// Attempt to call write() on the main thread.
#[cfg(not(windows))]
pub fn eager_write<T>(resource: Resource, buf: T) -> EagerWrite<Resource, T>
where
T: AsRef<[u8]>,
{
let mut table = RESOURCE_TABLE.lock().unwrap();
let maybe_repr = table.get_mut(&resource.rid);
match maybe_repr {
None => panic!("bad rid"),
Some(repr) => match repr {
Repr::TcpStream(ref mut tcp_stream) => {
// Unforunately we can't just call write() on tokio::net::TcpStream
use std::os::unix::io::AsRawFd;
use std::os::unix::io::FromRawFd;
use std::os::unix::io::IntoRawFd;
let mut std_tcp_stream =
unsafe { std::net::TcpStream::from_raw_fd(tcp_stream.as_raw_fd()) };
let write_result = std_tcp_stream.write(buf.as_ref());
// std_tcp_stream will close when it gets dropped. Thus...
let _ = std_tcp_stream.into_raw_fd();
match write_result {
Ok(nwrite) => Either::B(futures::future::ok((resource, buf, nwrite))),
Err(err) => {
if err.kind() == std::io::ErrorKind::WouldBlock {
Either::A(tokio_write::write(resource, buf))
} else {
Either::B(futures::future::err(err))
}
}
}
}
_ => Either::A(tokio_write::write(resource, buf)),
},
}
}
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type EagerAccept = Either<
tokio_util::Accept,
FutureResult<(TcpStream, SocketAddr), std::io::Error>,
>;
#[cfg(windows)]
pub fn eager_accept(resource: Resource) -> EagerAccept {
Either::A(tokio_util::accept(resource)).into()
}
// This is an optimization that Tokio should do.
// Attempt to call write() on the main thread.
#[cfg(not(windows))]
pub fn eager_accept(resource: Resource) -> EagerAccept {
let mut table = RESOURCE_TABLE.lock().unwrap();
let maybe_repr = table.get_mut(&resource.rid);
match maybe_repr {
None => panic!("bad rid"),
Some(repr) => match repr {
Repr::TcpListener(ref mut listener) => {
// Unforunately we can't just call write() on tokio::net::TcpStream
use std::os::unix::io::AsRawFd;
use std::os::unix::io::FromRawFd;
use std::os::unix::io::IntoRawFd;
let mut std_listener =
unsafe { std::net::TcpListener::from_raw_fd(listener.as_raw_fd()) };
let result = std_listener.accept();
// std_listener will close when it gets dropped. Thus...
let _ = std_listener.into_raw_fd();
match result {
Ok((std_stream, addr)) => {
let result = tokio::net::TcpStream::from_std(
std_stream,
&tokio::reactor::Handle::default(),
);
let tokio_stream = result.unwrap();
Either::B(futures::future::ok((tokio_stream, addr)))
}
Err(err) => {
if err.kind() == std::io::ErrorKind::WouldBlock {
Either::A(tokio_util::accept(resource))
} else {
Either::B(futures::future::err(err))
}
}
}
}
_ => Either::A(tokio_util::accept(resource)),
},
}
}