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use core::ffi::c_void;
use ash::vk;
/// A caller-provided `pNext` chain, stashed by one of the `set_next_*_chain`
/// setters until the Vulkan call that consumes it.
pub(crate) struct PnextChain(*mut vk::BaseOutStructure<'static>);
// SAFETY: The pointer is only dereferenced at the Vulkan call that consumes the
// chain. Each setter's contract keeps the chain valid and unaliased until then.
unsafe impl Send for PnextChain {}
unsafe impl Sync for PnextChain {}
impl PnextChain {
/// Wraps the raw chain pointer that a `set_next_*_chain` setter received.
pub(crate) fn new(chain: *mut c_void) -> Self {
Self(chain.cast())
}
/// Splices this chain in front of `existing`, the current `p_next` of a
/// Vulkan info struct, and returns the new chain head.
///
/// # Safety
///
/// The chain must still be valid, and the info struct must be passed to the
/// Vulkan call that consumes the chain.
pub(crate) unsafe fn splice_into(self, existing: *const c_void) -> *const c_void {
unsafe {
let mut tail = self.0;
while !(*tail).p_next.is_null() {
tail = (*tail).p_next;
}
(*tail).p_next = existing.cast_mut().cast();
}
self.0.cast()
}
}