gecko-dev/servo/components/allocator/lib.rs

72 строки
2.1 KiB
Rust

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
//! Selecting the default global allocator for Servo
#![cfg_attr(all(feature = "unstable", windows), feature(alloc_system, allocator_api))]
#![cfg_attr(feature = "unstable", feature(global_allocator))]
#[cfg(feature = "unstable")]
#[global_allocator]
static ALLOC: Allocator = Allocator;
pub use platform::*;
#[cfg(all(feature = "unstable", not(windows)))]
mod platform {
extern crate jemallocator;
pub use self::jemallocator::Jemalloc as Allocator;
use std::os::raw::c_void;
/// Get the size of a heap block.
pub unsafe extern "C" fn usable_size(ptr: *const c_void) -> usize {
jemallocator::usable_size(ptr)
}
/// Memory allocation APIs compatible with libc
pub mod libc_compat {
pub use super::jemallocator::ffi::{malloc, realloc, free};
}
}
#[cfg(all(feature = "unstable", windows))]
mod platform {
extern crate alloc_system;
extern crate kernel32;
pub use self::alloc_system::System as Allocator;
use self::kernel32::{GetProcessHeap, HeapSize, HeapValidate};
use std::os::raw::c_void;
/// Get the size of a heap block.
pub unsafe extern "C" fn usable_size(mut ptr: *const c_void) -> usize {
let heap = GetProcessHeap();
if HeapValidate(heap, 0, ptr) == 0 {
ptr = *(ptr as *const *const c_void).offset(-1);
}
HeapSize(heap, 0, ptr) as usize
}
}
#[cfg(not(feature = "unstable"))]
mod platform {
use std::os::raw::c_void;
/// Without `#[global_allocator]` we cannot be certain of what allocator is used
/// or how it is linked. We therefore disable memory reporting. (Return zero.)
pub unsafe extern "C" fn usable_size(_ptr: *const c_void) -> usize {
0
}
/// Memory allocation APIs compatible with libc
pub mod libc_compat {
extern crate libc;
pub use self::libc::{malloc, realloc, free};
}
}