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denoland-deno/serde_v8/serializable.rs
Bartek Iwańczuk dda0f1c343
refactor(serde_v8): split ZeroCopyBuf into JsBuffer and ToJsBuffer (#19566)
`ZeroCopyBuf` was convenient to use, but sometimes it did hide details
that some copies were necessary in certain cases. Also it made it way to easy
for the caller to pass around and convert into different values. This commit
splits `ZeroCopyBuf` into `JsBuffer` (an array buffer coming from V8) and
`ToJsBuffer` (a Rust buffer that will be converted into a V8 array buffer).

As a result some magical conversions were removed (they were never used)
limiting the API surface and preparing for changes in #19534.
2023-06-22 23:37:56 +02:00

149 lines
4.7 KiB
Rust

// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
use std::any::TypeId;
use std::mem::transmute_copy;
use crate::BigInt;
use crate::ByteString;
use crate::ToJsBuffer;
use crate::U16String;
/// Serializable exists to allow boxing values as "objects" to be serialized later,
/// this is particularly useful for async op-responses. This trait is a more efficient
/// replacement for erased-serde that makes less allocations, since it's specific to serde_v8
/// (and thus doesn't have to have generic outputs, etc...)
pub trait Serializable {
fn to_v8<'a>(
&mut self,
scope: &mut v8::HandleScope<'a>,
) -> Result<v8::Local<'a, v8::Value>, crate::Error>;
}
/// Allows all implementors of `serde::Serialize` to implement Serializable
impl<T: serde::Serialize> Serializable for T {
fn to_v8<'a>(
&mut self,
scope: &mut v8::HandleScope<'a>,
) -> Result<v8::Local<'a, v8::Value>, crate::Error> {
crate::to_v8(scope, self)
}
}
/// SerializablePkg exists to provide a fast path for op returns,
/// allowing them to avoid boxing primtives (ints/floats/bool/unit/...)
pub enum SerializablePkg {
Primitive(Primitive),
Serializable(Box<dyn Serializable>),
}
impl SerializablePkg {
pub fn to_v8<'a>(
&mut self,
scope: &mut v8::HandleScope<'a>,
) -> Result<v8::Local<'a, v8::Value>, crate::Error> {
match self {
Self::Primitive(x) => crate::to_v8(scope, x),
Self::Serializable(x) => x.to_v8(scope),
}
}
}
/// Primitive serves as a lightweight serializable wrapper around primitives
/// so that we can use them for async values
pub enum Primitive {
Unit,
Bool(bool),
Int8(i8),
Int16(i16),
Int32(i32),
Int64(i64),
UInt8(u8),
UInt16(u16),
UInt32(u32),
UInt64(u64),
Float32(f32),
Float64(f64),
String(String),
RustToV8Buf(ToJsBuffer),
ByteString(ByteString),
U16String(U16String),
BigInt(BigInt),
}
impl serde::Serialize for Primitive {
fn serialize<S>(&self, s: S) -> Result<S::Ok, S::Error>
where
S: serde::Serializer,
{
match self {
Self::Unit => ().serialize(s),
Self::Bool(x) => x.serialize(s),
Self::Int8(x) => x.serialize(s),
Self::Int16(x) => x.serialize(s),
Self::Int32(x) => x.serialize(s),
Self::Int64(x) => x.serialize(s),
Self::UInt8(x) => x.serialize(s),
Self::UInt16(x) => x.serialize(s),
Self::UInt32(x) => x.serialize(s),
Self::UInt64(x) => x.serialize(s),
Self::Float32(x) => x.serialize(s),
Self::Float64(x) => x.serialize(s),
Self::String(x) => x.serialize(s),
Self::RustToV8Buf(x) => x.serialize(s),
Self::ByteString(x) => x.serialize(s),
Self::U16String(x) => x.serialize(s),
Self::BigInt(x) => x.serialize(s),
}
}
}
impl<T: serde::Serialize + 'static> From<T> for SerializablePkg {
fn from(x: T) -> Self {
#[inline(always)]
fn tc<T, U>(src: T) -> U {
// SAFETY: the caller has ensured via the TypeId that the T and U types
// are the same.
let x = unsafe { transmute_copy(&src) };
std::mem::forget(src);
x
}
let tid = TypeId::of::<T>();
if tid == TypeId::of::<()>() {
Self::Primitive(Primitive::Unit)
} else if tid == TypeId::of::<bool>() {
Self::Primitive(Primitive::Bool(tc(x)))
} else if tid == TypeId::of::<i8>() {
Self::Primitive(Primitive::Int8(tc(x)))
} else if tid == TypeId::of::<i16>() {
Self::Primitive(Primitive::Int16(tc(x)))
} else if tid == TypeId::of::<i32>() {
Self::Primitive(Primitive::Int32(tc(x)))
} else if tid == TypeId::of::<i64>() {
Self::Primitive(Primitive::Int64(tc(x)))
} else if tid == TypeId::of::<u8>() {
Self::Primitive(Primitive::UInt8(tc(x)))
} else if tid == TypeId::of::<u16>() {
Self::Primitive(Primitive::UInt16(tc(x)))
} else if tid == TypeId::of::<u32>() {
Self::Primitive(Primitive::UInt32(tc(x)))
} else if tid == TypeId::of::<u64>() {
Self::Primitive(Primitive::UInt64(tc(x)))
} else if tid == TypeId::of::<f32>() {
Self::Primitive(Primitive::Float32(tc(x)))
} else if tid == TypeId::of::<f64>() {
Self::Primitive(Primitive::Float64(tc(x)))
} else if tid == TypeId::of::<String>() {
Self::Primitive(Primitive::String(tc(x)))
} else if tid == TypeId::of::<ToJsBuffer>() {
Self::Primitive(Primitive::RustToV8Buf(tc(x)))
} else if tid == TypeId::of::<ByteString>() {
Self::Primitive(Primitive::ByteString(tc(x)))
} else if tid == TypeId::of::<U16String>() {
Self::Primitive(Primitive::U16String(tc(x)))
} else if tid == TypeId::of::<BigInt>() {
Self::Primitive(Primitive::BigInt(tc(x)))
} else {
Self::Serializable(Box::new(x))
}
}
}