protobuf/rust/lib.rs

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//! Rust Protobuf Runtime

#[cfg(cpp_kernel)]
pub extern crate cpp as __runtime;
#[cfg(upb_kernel)]
pub extern crate upb as __runtime;

pub use __runtime::Arena;

use std::ops::Deref;
use std::ptr::NonNull;
use std::slice;

/// Represents serialized Protobuf wire format data. It's typically produced by
/// `<Message>.serialize()`.
pub struct SerializedData {
    data: NonNull<u8>,
    len: usize,
    arena: *mut Arena,
}

impl SerializedData {
    pub unsafe fn from_raw_parts(arena: *mut Arena, data: NonNull<u8>, len: usize) -> Self {
        SerializedData { arena, data, len }
    }
}

impl Deref for SerializedData {
    type Target = [u8];
    fn deref(&self) -> &Self::Target {
        unsafe { slice::from_raw_parts(self.data.as_ptr() as *const _, self.len) }
    }
}

impl Drop for SerializedData {
    fn drop(&mut self) {
        unsafe { Arena::free(self.arena) };
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_serialized_data_roundtrip() {
        let arena = unsafe { Arena::new() };
        let original_data = b"Hello world";
        let len = original_data.len();

        let serialized_data = unsafe {
            SerializedData::from_raw_parts(
                arena,
                NonNull::new(original_data as *const _ as *mut _).unwrap(),
                len,
            )
        };
        assert_eq!(&*serialized_data, b"Hello world");
    }
}