mirui 0.45.0

A lightweight, no_std ECS-driven UI framework for embedded, desktop, and WebAssembly
Documentation 
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use std::alloc::{GlobalAlloc, Layout, System};
use std::cell::Cell;

struct TrackingAllocator;

std::thread_local! {
    static TRACK_ALLOCATIONS: Cell<bool> = const { Cell::new(false) };
    static ALLOCATION_COUNT: Cell<usize> = const { Cell::new(0) };
}

unsafe impl GlobalAlloc for TrackingAllocator {
    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
        TRACK_ALLOCATIONS.with(|tracking| {
            if tracking.get() {
                ALLOCATION_COUNT.with(|count| count.set(count.get() + 1));
            }
        });
        // SAFETY: `layout` is forwarded unchanged to the system allocator.
        unsafe { System.alloc(layout) }
    }

    unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
        // SAFETY: `ptr` and `layout` came from this allocator's system allocation.
        unsafe { System.dealloc(ptr, layout) }
    }

    unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
        TRACK_ALLOCATIONS.with(|tracking| {
            if tracking.get() {
                ALLOCATION_COUNT.with(|count| count.set(count.get() + 1));
            }
        });
        // SAFETY: the allocation remains owned by the system allocator.
        unsafe { System.realloc(ptr, layout, new_size) }
    }
}

#[global_allocator]
static ALLOCATOR: TrackingAllocator = TrackingAllocator;

pub fn tracked_allocations(run: impl FnOnce()) -> usize {
    ALLOCATION_COUNT.with(|count| count.set(0));
    TRACK_ALLOCATIONS.with(|tracking| tracking.set(true));
    run();
    TRACK_ALLOCATIONS.with(|tracking| tracking.set(false));
    ALLOCATION_COUNT.with(Cell::get)
}