extern crate libc;
mod error;
use libc::{c_int, c_void, size_t};
use std::alloc::{GlobalAlloc, Layout};
const GC_SUCCESS: c_int = 0;
#[repr(C)]
struct GcStackBase {
mem_base: *const c_void,
reg_base: *const c_void,
}
#[link(name = "gc")]
extern "C" {
fn GC_allow_register_threads() -> c_void;
fn GC_free(ptr: *mut c_void);
fn GC_get_stack_base(stack_base: *mut GcStackBase) -> c_int;
fn GC_init() -> c_void;
fn GC_malloc(size: size_t) -> *mut c_void;
fn GC_register_my_thread(stack_base: *const GcStackBase) -> c_int;
fn GC_unregister_my_thread();
}
pub struct Allocator;
impl Allocator {
pub unsafe fn initialize() {
GC_init();
GC_allow_register_threads();
}
pub fn register_current_thread() -> Result<(), error::Error> {
let mut base = GcStackBase {
mem_base: std::ptr::null(),
reg_base: std::ptr::null(),
};
if unsafe { GC_get_stack_base(&mut base) } != GC_SUCCESS {
return Err(error::Error::new("failed to get stack base"));
} else if unsafe { GC_register_my_thread(&base) } != GC_SUCCESS {
return Err(error::Error::new("failed to register a thread for GC"));
}
Ok(())
}
pub fn unregister_current_thread() {
unsafe { GC_unregister_my_thread() }
}
}
unsafe impl GlobalAlloc for Allocator {
unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
GC_malloc(layout.size()) as *mut u8
}
unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) {
GC_free(ptr as *mut c_void)
}
}