ic-testkit-native 0.76.1

#![expect(
    unsafe_code,
    reason = "exercise unsafe reads using live, correctly sized test-owned buffers"
)]

use super::*;
use std::mem::MaybeUninit;

#[test]
fn clones_share_bytes_counts_and_reset_without_counting_observation() {
    let memory = MeteredMemory::<VectorMemory>::default();
    let alias = memory.clone();
    assert_eq!(memory.grow(1), 0);
    memory.write(0, b"abc");
    let mut bytes = [0; 3];
    alias.read(0, &mut bytes);
    assert_eq!(&bytes, b"abc");
    assert_eq!(alias.backing().size(), 1);
    assert_eq!(
        alias.counts(),
        MemoryIoCounts {
            reads: 1,
            read_bytes: 3,
            writes: 1,
            write_bytes: 3,
            grows: 1,
            grown_pages: 1,
            ..MemoryIoCounts::default()
        }
    );
    alias.reset();
    assert_eq!(memory.counts(), MemoryIoCounts::default());
    memory.read(0, &mut bytes);
    assert_eq!(&bytes, b"abc");
}

struct UnsafeOnly;
impl Memory for UnsafeOnly {
    fn size(&self) -> u64 {
        1
    }
    fn grow(&self, pages: u64) -> i64 {
        if pages == 0 { 1 } else { -1 }
    }
    fn read(&self, _: u64, _: &mut [u8]) {
        panic!("safe fallback must not run")
    }
    unsafe fn read_unsafe(&self, _: u64, dst: *mut u8, count: usize) {
        // SAFETY: Caller supplies count valid writable bytes.
        unsafe { dst.write_bytes(42, count) };
    }
    fn write(&self, _: u64, _: &[u8]) {
        panic!("injected write failure")
    }
}

#[test]
fn specialized_unsafe_reads_and_refused_growth_preserve_backing_contracts() {
    let memory = MeteredMemory::new(UnsafeOnly);
    let mut bytes = MaybeUninit::<[u8; 3]>::uninit();
    // SAFETY: The local destination has three writable bytes disjoint from memory.
    unsafe { memory.read_unsafe(0, bytes.as_mut_ptr().cast(), 3) };
    // SAFETY: The successful specialized read initialized all three bytes.
    assert_eq!(unsafe { bytes.assume_init() }, [42; 3]);
    assert_eq!(memory.grow(0), 1);
    assert_eq!(memory.grow(9), -1);
    let result = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| memory.write(0, b"abc")));
    assert!(result.is_err());
    assert_eq!(
        memory.counts(),
        MemoryIoCounts {
            reads: 1,
            read_bytes: 3,
            unsafe_reads: 1,
            unsafe_read_bytes: 3,
            writes: 1,
            write_bytes: 3,
            grows: 2,
            ..MemoryIoCounts::default()
        }
    );
}

#[test]
fn actual_counter_overflow_is_sticky_until_shared_reset() {
    for (index, counts) in [
        MemoryIoCounts {
            reads: u64::MAX,
            ..MemoryIoCounts::default()
        },
        MemoryIoCounts {
            read_bytes: u64::MAX,
            ..MemoryIoCounts::default()
        },
        MemoryIoCounts {
            unsafe_reads: u64::MAX,
            ..MemoryIoCounts::default()
        },
        MemoryIoCounts {
            unsafe_read_bytes: u64::MAX,
            ..MemoryIoCounts::default()
        },
        MemoryIoCounts {
            writes: u64::MAX,
            ..MemoryIoCounts::default()
        },
        MemoryIoCounts {
            write_bytes: u64::MAX,
            ..MemoryIoCounts::default()
        },
        MemoryIoCounts {
            grows: u64::MAX,
            ..MemoryIoCounts::default()
        },
        MemoryIoCounts {
            grown_pages: u64::MAX,
            ..MemoryIoCounts::default()
        },
    ]
    .into_iter()
    .enumerate()
    {
        let memory = MeteredMemory::<VectorMemory>::default();
        memory.grow(1);
        memory.write(0, b"X");
        memory.state.counts.set(counts);
        let alias = memory.clone();
        let mut byte = [0];
        match index {
            0 | 1 => memory.read(0, &mut byte),
            2 | 3 => {
                // SAFETY: The local byte is writable and disjoint from backing.
                unsafe { memory.read_unsafe(0, byte.as_mut_ptr(), 1) };
            }
            4 | 5 => memory.write(0, b"X"),
            6 => {
                memory.grow(0);
            }
            7 => {
                memory.grow(1);
            }
            _ => unreachable!(),
        }
        let counts = alias.counts();
        assert!(counts.overflowed, "counter {index}");
        assert_eq!(
            [
                counts.reads,
                counts.read_bytes,
                counts.unsafe_reads,
                counts.unsafe_read_bytes,
                counts.writes,
                counts.write_bytes,
                counts.grows,
                counts.grown_pages,
            ][index],
            u64::MAX
        );
        memory.read(0, &mut []);
        assert!(alias.counts().overflowed);
        alias.reset();
        assert_eq!(memory.counts(), MemoryIoCounts::default());
        memory.backing().read(0, &mut byte);
        assert_eq!(byte, *b"X");
        assert_eq!(memory.counts(), MemoryIoCounts::default());
    }
}

#[test]
fn zero_deltas_at_counter_limit_do_not_signal_overflow() {
    let memory = MeteredMemory::<VectorMemory>::default();
    memory.grow(1);
    memory.state.counts.set(MemoryIoCounts {
        read_bytes: u64::MAX,
        unsafe_read_bytes: u64::MAX,
        write_bytes: u64::MAX,
        grown_pages: u64::MAX,
        ..MemoryIoCounts::default()
    });
    memory.read(0, &mut []);
    let mut bytes = [];
    // SAFETY: An empty slice supplies a valid disjoint zero-length destination.
    unsafe { memory.read_unsafe(0, bytes.as_mut_ptr(), 0) };
    memory.write(0, &[]);
    assert_eq!(memory.grow(0), 1);
    assert_eq!(
        memory.counts(),
        MemoryIoCounts {
            reads: 2,
            read_bytes: u64::MAX,
            unsafe_reads: 1,
            unsafe_read_bytes: u64::MAX,
            writes: 1,
            write_bytes: u64::MAX,
            grows: 1,
            grown_pages: u64::MAX,
            overflowed: false,
        }
    );
}