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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
//! FfiDefault trait
//!
//! When we make a FFI call into Rust we always need to return a value, even if that value will be
//! ignored because we're flagging an exception. This trait defines what that value is for our
//! supported FFI types.
use paste::paste;
pub trait FfiDefault {
fn ffi_default() -> Self;
}
// Most types can be handled by delegating to Default
macro_rules! impl_ffi_default_with_default {
($($T:ty,)+) => { impl_ffi_default_with_default!($($T),+); };
($($T:ty),*) => {
$(
paste! {
impl FfiDefault for $T {
fn ffi_default() -> Self {
$T::default()
}
}
}
)*
};
}
impl_ffi_default_with_default! {
i8, u8, i16, u16, i32, u32, i64, u64, f32, f64
}
// Implement FfiDefault for the remaining types
impl FfiDefault for () {
fn ffi_default() {}
}
impl FfiDefault for *const std::ffi::c_void {
fn ffi_default() -> Self {
std::ptr::null()
}
}
impl FfiDefault for crate::RustBuffer {
fn ffi_default() -> Self {
unsafe { Self::from_raw_parts(std::ptr::null_mut(), 0, 0) }
}
}
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