emf-core-base-rs 0.1.3

Idiomatic Rust wrapper of the emf-core-base interface
Documentation 
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//! API of a sync handler.
use crate::ffi::collections::NonNullConst;
use crate::ffi::sys::sync_handler::{SyncHandlerBinding, SyncHandlerInterface};
use crate::ffi::Bool;

/// A borrowed sync handler.
#[derive(Debug, Copy, Clone, Ord, PartialOrd, Eq, PartialEq)]
pub struct SyncHandler<'a> {
    handler: &'a SyncHandlerInterface,
}

/// The API of a sync handler.
pub trait SyncHandlerAPI<'a> {
    /// Type of the sync handler.
    type Handler;

    /// Fetches a pointer that can be used with the interface.
    fn to_interface(&self) -> NonNullConst<SyncHandlerInterface>;

    /// Construct a new instance with the pointer.
    ///
    /// # Safety
    ///
    /// This function should not be used directly.
    unsafe fn from_interface(handler: NonNullConst<SyncHandlerInterface>) -> Self::Handler;

    /// Locks the synchronisation handler.
    ///
    /// The calling thread is stalled until the lock can be acquired.
    /// Only one thread can hold the lock at a time.
    ///
    /// # Safety
    ///
    /// The function crosses the ffi boundary.
    /// Direct usage of a [SyncHandlerAPI] may break some invariants
    /// of the sys api, if not handled with care.
    unsafe fn lock(&self);

    /// Tries to lock the synchronisation handler.
    ///
    /// The function fails if another thread already holds the lock.
    ///
    /// # Return
    ///
    /// [true] on success and [false] otherwise.
    ///
    /// # Safety
    ///
    /// The function crosses the ffi boundary.
    /// Direct usage of a [SyncHandlerAPI] may break some invariants
    /// of the sys api, if not handled with care.
    unsafe fn try_lock(&self) -> bool;

    /// Unlocks the synchronisation handler.
    ///
    /// # Safety
    ///
    /// The function crosses the ffi boundary.
    /// Trying to call this function without prior locking is undefined behaviour.
    /// Direct usage of a [SyncHandlerAPI] may break some invariants
    /// of the sys api, if not handled with care.
    unsafe fn unlock(&self);
}

impl SyncHandlerAPI<'_> for SyncHandler<'_> {
    type Handler = Self;

    #[inline]
    fn to_interface(&self) -> NonNullConst<SyncHandlerInterface> {
        NonNullConst::from(self.handler)
    }

    #[inline]
    unsafe fn from_interface(handler: NonNullConst<SyncHandlerInterface>) -> Self::Handler {
        Self {
            handler: &*handler.as_ptr(),
        }
    }

    #[inline]
    unsafe fn lock(&self) {
        self.handler.lock()
    }

    #[inline]
    unsafe fn try_lock(&self) -> bool {
        self.handler.try_lock() == Bool::True
    }

    #[inline]
    unsafe fn unlock(&self) {
        self.handler.unlock()
    }
}