diff options
Diffstat (limited to 'src/tools/rust-analyzer/crates/proc-macro-srv/src/abis/abi_1_58/proc_macro/bridge/buffer.rs')
-rw-r--r-- | src/tools/rust-analyzer/crates/proc-macro-srv/src/abis/abi_1_58/proc_macro/bridge/buffer.rs | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/src/tools/rust-analyzer/crates/proc-macro-srv/src/abis/abi_1_58/proc_macro/bridge/buffer.rs b/src/tools/rust-analyzer/crates/proc-macro-srv/src/abis/abi_1_58/proc_macro/bridge/buffer.rs new file mode 100644 index 000000000..d82669d3e --- /dev/null +++ b/src/tools/rust-analyzer/crates/proc-macro-srv/src/abis/abi_1_58/proc_macro/bridge/buffer.rs @@ -0,0 +1,143 @@ +//! Buffer management for same-process client<->server communication. + +use std::io::{self, Write}; +use std::mem; +use std::ops::{Deref, DerefMut}; +use std::slice; + +#[repr(C)] +pub struct Buffer<T: Copy> { + data: *mut T, + len: usize, + capacity: usize, + reserve: extern "C" fn(Buffer<T>, usize) -> Buffer<T>, + drop: extern "C" fn(Buffer<T>), +} + +unsafe impl<T: Copy + Sync> Sync for Buffer<T> {} +unsafe impl<T: Copy + Send> Send for Buffer<T> {} + +impl<T: Copy> Default for Buffer<T> { + fn default() -> Self { + Self::from(vec![]) + } +} + +impl<T: Copy> Deref for Buffer<T> { + type Target = [T]; + fn deref(&self) -> &[T] { + unsafe { slice::from_raw_parts(self.data as *const T, self.len) } + } +} + +impl<T: Copy> DerefMut for Buffer<T> { + fn deref_mut(&mut self) -> &mut [T] { + unsafe { slice::from_raw_parts_mut(self.data, self.len) } + } +} + +impl<T: Copy> Buffer<T> { + pub(super) fn new() -> Self { + Self::default() + } + + pub(super) fn clear(&mut self) { + self.len = 0; + } + + pub(super) fn take(&mut self) -> Self { + mem::take(self) + } + + // We have the array method separate from extending from a slice. This is + // because in the case of small arrays, codegen can be more efficient + // (avoiding a memmove call). With extend_from_slice, LLVM at least + // currently is not able to make that optimization. + pub(super) fn extend_from_array<const N: usize>(&mut self, xs: &[T; N]) { + if xs.len() > (self.capacity - self.len) { + let b = self.take(); + *self = (b.reserve)(b, xs.len()); + } + unsafe { + xs.as_ptr().copy_to_nonoverlapping(self.data.add(self.len), xs.len()); + self.len += xs.len(); + } + } + + pub(super) fn extend_from_slice(&mut self, xs: &[T]) { + if xs.len() > (self.capacity - self.len) { + let b = self.take(); + *self = (b.reserve)(b, xs.len()); + } + unsafe { + xs.as_ptr().copy_to_nonoverlapping(self.data.add(self.len), xs.len()); + self.len += xs.len(); + } + } + + pub(super) fn push(&mut self, v: T) { + // The code here is taken from Vec::push, and we know that reserve() + // will panic if we're exceeding isize::MAX bytes and so there's no need + // to check for overflow. + if self.len == self.capacity { + let b = self.take(); + *self = (b.reserve)(b, 1); + } + unsafe { + *self.data.add(self.len) = v; + self.len += 1; + } + } +} + +impl Write for Buffer<u8> { + fn write(&mut self, xs: &[u8]) -> io::Result<usize> { + self.extend_from_slice(xs); + Ok(xs.len()) + } + + fn write_all(&mut self, xs: &[u8]) -> io::Result<()> { + self.extend_from_slice(xs); + Ok(()) + } + + fn flush(&mut self) -> io::Result<()> { + Ok(()) + } +} + +impl<T: Copy> Drop for Buffer<T> { + fn drop(&mut self) { + let b = self.take(); + (b.drop)(b); + } +} + +impl<T: Copy> From<Vec<T>> for Buffer<T> { + fn from(mut v: Vec<T>) -> Self { + let (data, len, capacity) = (v.as_mut_ptr(), v.len(), v.capacity()); + mem::forget(v); + + // This utility function is nested in here because it can *only* + // be safely called on `Buffer`s created by *this* `proc_macro`. + fn to_vec<T: Copy>(b: Buffer<T>) -> Vec<T> { + unsafe { + let Buffer { data, len, capacity, .. } = b; + mem::forget(b); + Vec::from_raw_parts(data, len, capacity) + } + } + + extern "C" fn reserve<T: Copy>(b: Buffer<T>, additional: usize) -> Buffer<T> { + let mut v = to_vec(b); + v.reserve(additional); + Buffer::from(v) + } + + extern "C" fn drop<T: Copy>(b: Buffer<T>) { + mem::drop(to_vec(b)); + } + + Buffer { data, len, capacity, reserve, drop } + } +} |