Update to new allocator API

src/lib.rs

-#![feature(allocator)]
+#![feature(alloc)]
+#![feature(allocator_api)]
 #![feature(const_fn)]
 #![feature(try_trait)]
-
-#![allocator]
 #![no_std]
 
+extern crate alloc;
 extern crate uefi;
 
+use alloc::heap::{Alloc, AllocErr, Layout};
 use core::ops::Try;
 use uefi::memory::MemoryType;
 use uefi::system::SystemTable;
@@ -27,60 +28,29 @@ fn get_uefi() -> Option<&'static mut SystemTable> {
     }
 }
 
-#[no_mangle]
-pub extern fn __rust_allocate(size: usize, _align: usize) -> *mut u8 {
-    if let Some(ref mut uefi) = get_uefi() {
-        let mut ptr = 0;
-        if let Err(err) = (uefi.BootServices.AllocatePool)(MemoryType::EfiLoaderData, size, &mut ptr).into_result() {
-            panic!("__rust_allocate: uefi returned {:?}", err);
+pub struct Allocator;
+
+unsafe impl<'a> Alloc for &'a Allocator {
+    unsafe fn alloc(&mut self, layout: Layout) -> Result<*mut u8, AllocErr> {
+        if let Some(ref mut uefi) = get_uefi() {
+            let mut ptr = 0;
+            if let Err(_) = (uefi.BootServices.AllocatePool)(MemoryType::EfiLoaderData, layout.size(), &mut ptr).into_result() {
+                Err(AllocErr::Exhausted {
+                    request: layout
+                })
+            } else {
+                Ok(ptr as *mut u8)
+            }
+        } else {
+            panic!("__rust_allocate: uefi not initialized");
         }
-        ptr as *mut u8
-    } else {
-        panic!("__rust_allocate: uefi not initialized");
     }
-}
 
-#[no_mangle]
-pub extern fn __rust_allocate_zeroed(size: usize, align: usize) -> *mut u8 {
-    use core::ptr;
-    
-    let ptr = __rust_allocate(size, align);
-    unsafe { ptr::write_bytes(ptr, 0, size) };
-    ptr
-}
-
-#[no_mangle]
-pub extern fn __rust_deallocate(ptr: *mut u8, _size: usize, _align: usize) {
-    if let Some(ref mut uefi) = get_uefi() {
-        let _ = (uefi.BootServices.FreePool)(ptr as usize);
-    } else {
-        panic!("__rust_deallocate: uefi not initialized");
+    unsafe fn dealloc(&mut self, ptr: *mut u8, _layout: Layout) {
+        if let Some(ref mut uefi) = get_uefi() {
+            let _ = (uefi.BootServices.FreePool)(ptr as usize);
+        } else {
+            panic!("__rust_deallocate: uefi not initialized");
+        }
     }
 }
-
-#[no_mangle]
-pub extern fn __rust_usable_size(size: usize, _align: usize) -> usize {
-    size
-}
-
-#[no_mangle]
-pub extern fn __rust_reallocate_inplace(_ptr: *mut u8, size: usize,
-    _new_size: usize, _align: usize) -> usize
-{
-    size
-}
-
-#[no_mangle]
-pub extern fn __rust_reallocate(ptr: *mut u8, size: usize, new_size: usize,
-                                align: usize) -> *mut u8 {
-    use core::{ptr, cmp};
-
-    // from: https://github.com/rust-lang/rust/blob/
-    //     c66d2380a810c9a2b3dbb4f93a830b101ee49cc2/
-    //     src/liballoc_system/lib.rs#L98-L101
-
-    let new_ptr = __rust_allocate(new_size, align);
-    unsafe { ptr::copy(ptr, new_ptr, cmp::min(size, new_size)) };
-    __rust_deallocate(ptr, size, align);
-    new_ptr
-}