Use the new GlobalAlloc trait

pull/61/head
Simon Sapin 7 years ago
parent 6a8f0a27e9
commit 498ac29974

@ -28,7 +28,7 @@ For instance, a custom implementation of `Box` might write `Drop` like this:
```rust ```rust
#![feature(ptr_internals, allocator_api, unique)] #![feature(ptr_internals, allocator_api, unique)]
use std::heap::{Heap, Alloc, Layout}; use std::alloc::{Global, GlobalAlloc, Layout, Void};
use std::mem; use std::mem;
use std::ptr::{drop_in_place, Unique}; use std::ptr::{drop_in_place, Unique};
@ -38,7 +38,7 @@ impl<T> Drop for Box<T> {
fn drop(&mut self) { fn drop(&mut self) {
unsafe { unsafe {
drop_in_place(self.ptr.as_ptr()); drop_in_place(self.ptr.as_ptr());
Heap.dealloc(self.ptr.as_ptr() as *mut u8, Layout::new::<T>()) Global.dealloc(self.ptr.as_ptr() as *mut Void, Layout::new::<T>())
} }
} }
} }
@ -54,7 +54,7 @@ However this wouldn't work:
```rust ```rust
#![feature(allocator_api, ptr_internals, unique)] #![feature(allocator_api, ptr_internals, unique)]
use std::heap::{Heap, Alloc, Layout}; use std::alloc::{Global, GlobalAlloc, Layout, Void};
use std::ptr::{drop_in_place, Unique}; use std::ptr::{drop_in_place, Unique};
use std::mem; use std::mem;
@ -64,7 +64,7 @@ impl<T> Drop for Box<T> {
fn drop(&mut self) { fn drop(&mut self) {
unsafe { unsafe {
drop_in_place(self.ptr.as_ptr()); drop_in_place(self.ptr.as_ptr());
Heap.dealloc(self.ptr.as_ptr() as *mut u8, Layout::new::<T>()); Global.dealloc(self.ptr.as_ptr() as *mut Void, Layout::new::<T>());
} }
} }
} }
@ -76,7 +76,7 @@ impl<T> Drop for SuperBox<T> {
unsafe { unsafe {
// Hyper-optimized: deallocate the box's contents for it // Hyper-optimized: deallocate the box's contents for it
// without `drop`ing the contents // without `drop`ing the contents
Heap.dealloc(self.my_box.ptr.as_ptr() as *mut u8, Layout::new::<T>()); Global.dealloc(self.my_box.ptr.as_ptr() as *mut Void, Layout::new::<T>());
} }
} }
} }
@ -125,7 +125,7 @@ of Self during `drop` is to use an Option:
```rust ```rust
#![feature(allocator_api, ptr_internals, unique)] #![feature(allocator_api, ptr_internals, unique)]
use std::heap::{Alloc, Heap, Layout}; use std::alloc::{GlobalAlloc, Global, Layout, Void};
use std::ptr::{drop_in_place, Unique}; use std::ptr::{drop_in_place, Unique};
use std::mem; use std::mem;
@ -135,7 +135,7 @@ impl<T> Drop for Box<T> {
fn drop(&mut self) { fn drop(&mut self) {
unsafe { unsafe {
drop_in_place(self.ptr.as_ptr()); drop_in_place(self.ptr.as_ptr());
Heap.dealloc(self.ptr.as_ptr() as *mut u8, Layout::new::<T>()); Global.dealloc(self.ptr.as_ptr() as *mut Void, Layout::new::<T>());
} }
} }
} }
@ -149,7 +149,7 @@ impl<T> Drop for SuperBox<T> {
// without `drop`ing the contents. Need to set the `box` // without `drop`ing the contents. Need to set the `box`
// field as `None` to prevent Rust from trying to Drop it. // field as `None` to prevent Rust from trying to Drop it.
let my_box = self.my_box.take().unwrap(); let my_box = self.my_box.take().unwrap();
Heap.dealloc(my_box.ptr.as_ptr() as *mut u8, Layout::new::<T>()); Global.dealloc(my_box.ptr.as_ptr() as *mut Void, Layout::new::<T>());
mem::forget(my_box); mem::forget(my_box);
} }
} }

@ -9,7 +9,7 @@ use std::ptr::{Unique, self};
use std::mem; use std::mem;
use std::ops::{Deref, DerefMut}; use std::ops::{Deref, DerefMut};
use std::marker::PhantomData; use std::marker::PhantomData;
use std::heap::{Alloc, Layout, Heap}; use std::alloc::{GlobalAlloc, Layout, Global};
struct RawVec<T> { struct RawVec<T> {
ptr: Unique<T>, ptr: Unique<T>,
@ -34,21 +34,20 @@ impl<T> RawVec<T> {
assert!(elem_size != 0, "capacity overflow"); assert!(elem_size != 0, "capacity overflow");
let (new_cap, ptr) = if self.cap == 0 { let (new_cap, ptr) = if self.cap == 0 {
let ptr = Heap.alloc(Layout::array::<T>(1).unwrap()); let ptr = Global.alloc(Layout::array::<T>(1).unwrap());
(1, ptr) (1, ptr)
} else { } else {
let new_cap = 2 * self.cap; let new_cap = 2 * self.cap;
let ptr = Heap.realloc(self.ptr.as_ptr() as *mut _, let ptr = Global.realloc(self.ptr.as_ptr() as *mut _,
Layout::array::<T>(self.cap).unwrap(), Layout::array::<T>(self.cap).unwrap(),
Layout::array::<T>(new_cap).unwrap()); Layout::array::<T>(new_cap).unwrap().size());
(new_cap, ptr) (new_cap, ptr)
}; };
// If allocate or reallocate fail, oom // If allocate or reallocate fail, oom
let ptr = match ptr { if ptr.is_null() {
Ok(ptr) => ptr, Global.oom()
Err(err) => Heap.oom(err), }
};
self.ptr = Unique::new_unchecked(ptr as *mut _); self.ptr = Unique::new_unchecked(ptr as *mut _);
self.cap = new_cap; self.cap = new_cap;
@ -61,8 +60,8 @@ impl<T> Drop for RawVec<T> {
let elem_size = mem::size_of::<T>(); let elem_size = mem::size_of::<T>();
if self.cap != 0 && elem_size != 0 { if self.cap != 0 && elem_size != 0 {
unsafe { unsafe {
Heap.dealloc(self.ptr.as_ptr() as *mut _, Global.dealloc(self.ptr.as_ptr() as *mut _,
Layout::array::<T>(self.cap).unwrap()); Layout::array::<T>(self.cap).unwrap());
} }
} }
} }

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