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use std::ops::Deref;
use std::ops::DerefMut;
use std::ops::Range;
use std::rc::Rc;
use super::rawbytes;
use super::transl8::FromV8;
#[derive(Clone)]
pub struct V8Slice {
pub(crate) store: v8::SharedRef<v8::BackingStore>,
pub(crate) range: Range<usize>,
}
unsafe impl Send for V8Slice {}
impl V8Slice {
pub fn from_buffer(
buffer: v8::Local<v8::ArrayBuffer>,
range: Range<usize>,
) -> Result<Self, v8::DataError> {
let store = buffer.get_backing_store();
if store.is_shared() {
return Err(v8::DataError::BadType {
actual: "shared ArrayBufferView",
expected: "non-shared ArrayBufferView",
});
}
Ok(Self { store, range })
}
fn as_slice(&self) -> &[u8] {
unsafe { &*(&self.store[self.range.clone()] as *const _ as *const [u8]) }
}
fn as_slice_mut(&mut self) -> &mut [u8] {
#[allow(clippy::cast_ref_to_mut)]
unsafe {
&mut *(&self.store[self.range.clone()] as *const _ as *mut [u8])
}
}
}
pub(crate) fn to_ranged_buffer<'s>(
scope: &mut v8::HandleScope<'s>,
value: v8::Local<v8::Value>,
) -> Result<(v8::Local<'s, v8::ArrayBuffer>, Range<usize>), v8::DataError> {
if let Ok(view) = v8::Local::<v8::ArrayBufferView>::try_from(value) {
let (offset, len) = (view.byte_offset(), view.byte_length());
let buffer = view.buffer(scope).ok_or(v8::DataError::NoData {
expected: "view to have a buffer",
})?;
let buffer = v8::Local::new(scope, buffer); return Ok((buffer, offset..offset + len));
}
let b: v8::Local<v8::ArrayBuffer> = value.try_into()?;
let b = v8::Local::new(scope, b); Ok((b, 0..b.byte_length()))
}
impl FromV8 for V8Slice {
fn from_v8(
scope: &mut v8::HandleScope,
value: v8::Local<v8::Value>,
) -> Result<Self, crate::Error> {
to_ranged_buffer(scope, value)
.and_then(|(b, r)| Self::from_buffer(b, r))
.map_err(|_| crate::Error::ExpectedBuffer)
}
}
impl Deref for V8Slice {
type Target = [u8];
fn deref(&self) -> &[u8] {
self.as_slice()
}
}
impl DerefMut for V8Slice {
fn deref_mut(&mut self) -> &mut [u8] {
self.as_slice_mut()
}
}
impl AsRef<[u8]> for V8Slice {
fn as_ref(&self) -> &[u8] {
self.as_slice()
}
}
impl AsMut<[u8]> for V8Slice {
fn as_mut(&mut self) -> &mut [u8] {
self.as_slice_mut()
}
}
impl V8Slice {
fn rc_into_byte_parts(self: Rc<Self>) -> (*const u8, usize, *mut V8Slice) {
let (ptr, len) = {
let slice = self.as_ref();
(slice.as_ptr(), slice.len())
};
let rc_raw = Rc::into_raw(self);
let data = rc_raw as *mut V8Slice;
(ptr, len, data)
}
}
impl From<V8Slice> for bytes::Bytes {
fn from(v8slice: V8Slice) -> Self {
let (ptr, len, data) = Rc::new(v8slice).rc_into_byte_parts();
rawbytes::RawBytes::new_raw(ptr, len, data.cast(), &V8SLICE_VTABLE)
}
}
const V8SLICE_VTABLE: rawbytes::Vtable = rawbytes::Vtable {
clone: v8slice_clone,
drop: v8slice_drop,
to_vec: v8slice_to_vec,
};
unsafe fn v8slice_clone(
data: &rawbytes::AtomicPtr<()>,
ptr: *const u8,
len: usize,
) -> bytes::Bytes {
let rc = Rc::from_raw(*data as *const V8Slice);
let (_, _, data) = rc.clone().rc_into_byte_parts();
std::mem::forget(rc);
rawbytes::RawBytes::new_raw(ptr, len, data.cast(), &V8SLICE_VTABLE)
}
unsafe fn v8slice_to_vec(
data: &rawbytes::AtomicPtr<()>,
ptr: *const u8,
len: usize,
) -> Vec<u8> {
let rc = Rc::from_raw(*data as *const V8Slice);
std::mem::forget(rc);
Vec::from_raw_parts(ptr as _, len, len)
}
unsafe fn v8slice_drop(
data: &mut rawbytes::AtomicPtr<()>,
_: *const u8,
_: usize,
) {
drop(Rc::from_raw(*data as *const V8Slice))
}