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denoland-deno/cli/ops/dispatch_json.rs
2019-08-26 07:48:40 -04:00

116 lines
3.1 KiB
Rust

// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
use crate::state::ThreadSafeState;
use crate::tokio_util;
use deno::*;
use futures::Future;
use futures::Poll;
pub use serde_derive::Deserialize;
use serde_json::json;
pub use serde_json::Value;
pub type AsyncJsonOp = Box<dyn Future<Item = Value, Error = ErrBox> + Send>;
pub enum JsonOp {
Sync(Value),
Async(AsyncJsonOp),
}
fn json_err(err: ErrBox) -> Value {
use crate::deno_error::GetErrorKind;
json!({
"message": err.to_string(),
"kind": err.kind() as u32,
})
}
pub type Dispatcher = fn(
state: &ThreadSafeState,
args: Value,
zero_copy: Option<PinnedBuf>,
) -> Result<JsonOp, ErrBox>;
fn serialize_result(
promise_id: Option<u64>,
result: Result<Value, ErrBox>,
) -> Buf {
let value = match result {
Ok(v) => json!({ "ok": v, "promiseId": promise_id }),
Err(err) => json!({ "err": json_err(err), "promiseId": promise_id }),
};
let mut vec = serde_json::to_vec(&value).unwrap();
debug!("JSON response pre-align, len={}", vec.len());
// Align to 32bit word, padding with the space character.
vec.resize((vec.len() + 3usize) & !3usize, b' ');
vec.into_boxed_slice()
}
#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
struct AsyncArgs {
promise_id: Option<u64>,
}
pub fn dispatch(
d: Dispatcher,
state: &ThreadSafeState,
control: &[u8],
zero_copy: Option<PinnedBuf>,
) -> CoreOp {
let async_args: AsyncArgs = serde_json::from_slice(control).unwrap();
let promise_id = async_args.promise_id;
let is_sync = promise_id.is_none();
let result = serde_json::from_slice(control)
.map_err(ErrBox::from)
.and_then(move |args| d(state, args, zero_copy));
match result {
Ok(JsonOp::Sync(sync_value)) => {
assert!(promise_id.is_none());
CoreOp::Sync(serialize_result(promise_id, Ok(sync_value)))
}
Ok(JsonOp::Async(fut)) => {
assert!(promise_id.is_some());
let fut2 = Box::new(fut.then(move |result| -> Result<Buf, ()> {
Ok(serialize_result(promise_id, result))
}));
CoreOp::Async(fut2)
}
Err(sync_err) => {
let buf = serialize_result(promise_id, Err(sync_err));
if is_sync {
CoreOp::Sync(buf)
} else {
CoreOp::Async(Box::new(futures::future::ok(buf)))
}
}
}
}
// This is just type conversion. Implement From trait?
// See https://github.com/tokio-rs/tokio/blob/ffd73a64e7ec497622b7f939e38017afe7124dc4/tokio-fs/src/lib.rs#L76-L85
fn convert_blocking_json<F>(f: F) -> Poll<Value, ErrBox>
where
F: FnOnce() -> Result<Value, ErrBox>,
{
use futures::Async::*;
match tokio_threadpool::blocking(f) {
Ok(Ready(Ok(v))) => Ok(Ready(v)),
Ok(Ready(Err(err))) => Err(err),
Ok(NotReady) => Ok(NotReady),
Err(err) => panic!("blocking error {}", err),
}
}
pub fn blocking_json<F>(is_sync: bool, f: F) -> Result<JsonOp, ErrBox>
where
F: 'static + Send + FnOnce() -> Result<Value, ErrBox>,
{
if is_sync {
Ok(JsonOp::Sync(f()?))
} else {
Ok(JsonOp::Async(Box::new(futures::sync::oneshot::spawn(
tokio_util::poll_fn(move || convert_blocking_json(f)),
&tokio_executor::DefaultExecutor::current(),
))))
}
}