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denoland-deno/cli/ops/dispatch_json.rs
2020-01-24 15:10:49 -05:00

117 lines
3.2 KiB
Rust

// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
use deno_core::*;
use futures::future::FutureExt;
pub use serde_derive::Deserialize;
use serde_json::json;
pub use serde_json::Value;
use std::future::Future;
use std::pin::Pin;
use tokio::task;
pub type AsyncJsonOp =
Pin<Box<dyn Future<Output = Result<Value, ErrBox>> + Send>>;
pub enum JsonOp {
Sync(Value),
Async(AsyncJsonOp),
/// AsyncUnref is the variation of Async, which doesn't block the program
/// exiting.
AsyncUnref(AsyncJsonOp),
}
fn json_err(err: ErrBox) -> Value {
use crate::deno_error::GetErrorKind;
json!({
"message": err.to_string(),
"kind": err.kind() as u32,
})
}
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 json_op<D>(d: D) -> impl Fn(&[u8], Option<ZeroCopyBuf>) -> CoreOp
where
D: Fn(Value, Option<ZeroCopyBuf>) -> Result<JsonOp, ErrBox>,
{
move |control: &[u8], zero_copy: Option<ZeroCopyBuf>| {
let async_args: AsyncArgs = match serde_json::from_slice(control) {
Ok(args) => args,
Err(e) => {
let buf = serialize_result(None, Err(ErrBox::from(e)));
return CoreOp::Sync(buf);
}
};
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(|args| d(args, zero_copy));
// Convert to CoreOp
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 = fut.then(move |result| {
futures::future::ok(serialize_result(promise_id, result))
});
CoreOp::Async(fut2.boxed())
}
Ok(JsonOp::AsyncUnref(fut)) => {
assert!(promise_id.is_some());
let fut2 = fut.then(move |result| {
futures::future::ok(serialize_result(promise_id, result))
});
CoreOp::AsyncUnref(fut2.boxed())
}
Err(sync_err) => {
let buf = serialize_result(promise_id, Err(sync_err));
if is_sync {
CoreOp::Sync(buf)
} else {
CoreOp::Async(futures::future::ok(buf).boxed())
}
}
}
}
}
pub fn blocking_json<F>(is_sync: bool, f: F) -> Result<JsonOp, ErrBox>
where
F: 'static + Send + FnOnce() -> Result<Value, ErrBox> + Unpin,
{
if is_sync {
Ok(JsonOp::Sync(f()?))
} else {
let fut = async move {
task::spawn_blocking(move || f())
.await
.map_err(ErrBox::from)?
}
.boxed();
Ok(JsonOp::Async(fut.boxed()))
}
}