rb_allocator/
lib.rs

1//! Allocator which reports mem usage to the Ruby GC
2//!
3//! This crate exports, one type, `RbAllocator`, which implements the `GlobalAlloc` trait. It is a
4//! simple wrapper over the system allocator which reports memory usage to Ruby using
5//! `rb_gc_adjust_memory_usage`
6
7use rb_sys::{rb_gc_adjust_memory_usage, ssize_t};
8use std::alloc::{GlobalAlloc, Layout, System};
9
10pub struct RbAllocator;
11
12unsafe impl GlobalAlloc for RbAllocator {
13    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
14        let ret = System.alloc(layout);
15        if !ret.is_null() {
16            rb_gc_adjust_memory_usage(layout.size() as ssize_t)
17        }
18        ret
19    }
20
21    unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
22        let ret = System.alloc_zeroed(layout);
23        if !ret.is_null() {
24            rb_gc_adjust_memory_usage(layout.size() as ssize_t)
25        }
26        ret
27    }
28
29    unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
30        System.dealloc(ptr, layout);
31        rb_gc_adjust_memory_usage(0 - (layout.size() as ssize_t));
32    }
33
34    unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
35        let ret = System.realloc(ptr, layout, new_size);
36        if !ret.is_null() {
37            rb_gc_adjust_memory_usage((new_size as isize - layout.size() as isize) as ssize_t);
38        }
39        ret
40    }
41}
42
43#[macro_export]
44macro_rules! ruby_global_allocator {
45    () => {
46        use $crate::RbAllocator;
47        #[global_allocator]
48        static RUBY_GLOBAL_ALLOCATOR: RbAllocator = RbAllocator;
49    };
50}
rb_allocator/lib.rs

rb_allocator/
lib.rs
