mirror of
https://github.com/denoland/deno.git
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107 lines
2.6 KiB
Rust
107 lines
2.6 KiB
Rust
// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
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use super::transl8::{FromV8, ToV8};
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use crate::magic::transl8::impl_magic;
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use crate::Error;
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use smallvec::SmallVec;
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use std::mem::size_of;
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const USIZE2X: usize = size_of::<usize>() * 2;
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#[derive(
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PartialEq,
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Eq,
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Clone,
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Debug,
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Default,
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derive_more::Deref,
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derive_more::DerefMut,
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derive_more::AsRef,
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derive_more::AsMut,
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)]
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#[as_mut(forward)]
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#[as_ref(forward)]
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pub struct ByteString(SmallVec<[u8; USIZE2X]>);
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impl_magic!(ByteString);
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// const-assert that Vec<u8> and SmallVec<[u8; size_of::<usize>() * 2]> have a same size.
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// Note from https://docs.rs/smallvec/latest/smallvec/#union -
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// smallvec can still be larger than Vec if the inline buffer is
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// larger than two machine words.
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const _: () =
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assert!(size_of::<Vec<u8>>() == size_of::<SmallVec<[u8; USIZE2X]>>());
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impl ToV8 for ByteString {
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fn to_v8<'a>(
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&mut self,
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scope: &mut v8::HandleScope<'a>,
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) -> Result<v8::Local<'a, v8::Value>, crate::Error> {
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let v =
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v8::String::new_from_one_byte(scope, self, v8::NewStringType::Normal)
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.unwrap();
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Ok(v.into())
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}
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}
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impl FromV8 for ByteString {
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fn from_v8(
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scope: &mut v8::HandleScope,
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value: v8::Local<v8::Value>,
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) -> Result<Self, crate::Error> {
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let v8str = v8::Local::<v8::String>::try_from(value)
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.map_err(|_| Error::ExpectedString)?;
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if !v8str.contains_only_onebyte() {
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return Err(Error::ExpectedLatin1);
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}
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let len = v8str.length();
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let mut buffer = SmallVec::with_capacity(len);
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#[allow(clippy::uninit_vec)]
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// SAFETY: we set length == capacity (see previous line),
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// before immediately writing into that buffer and sanity check with an assert
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unsafe {
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buffer.set_len(len);
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let written = v8str.write_one_byte(
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scope,
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&mut buffer,
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0,
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v8::WriteOptions::NO_NULL_TERMINATION,
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);
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assert!(written == len);
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}
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Ok(Self(buffer))
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}
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}
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// smallvec does not impl From/Into traits
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// like Vec<u8> does. So here we are.
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impl From<Vec<u8>> for ByteString {
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fn from(vec: Vec<u8>) -> Self {
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ByteString(SmallVec::from_vec(vec))
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}
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}
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#[allow(clippy::from_over_into)]
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impl Into<Vec<u8>> for ByteString {
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fn into(self) -> Vec<u8> {
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self.0.into_vec()
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}
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}
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impl From<&[u8]> for ByteString {
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fn from(s: &[u8]) -> Self {
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ByteString(SmallVec::from_slice(s))
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}
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}
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impl From<&str> for ByteString {
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fn from(s: &str) -> Self {
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let v: Vec<u8> = s.into();
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ByteString::from(v)
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}
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}
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impl From<String> for ByteString {
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fn from(s: String) -> Self {
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ByteString::from(s.into_bytes())
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}
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}
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