adaptivegrain/vapoursynth/src/function.rs
2019-05-30 11:06:53 +00:00

124 lines
3.5 KiB
Rust

//! VapourSynth callable functions.
use std::marker::PhantomData;
use std::ops::{Deref, DerefMut};
use std::os::raw::c_void;
use std::ptr::NonNull;
use std::{mem, panic, process};
use vapoursynth_sys as ffi;
use api::API;
use core::CoreRef;
use map::{Map, MapRef, MapRefMut};
/// Holds a reference to a function that may be called.
#[derive(Debug)]
pub struct Function<'core> {
handle: NonNull<ffi::VSFuncRef>,
_owner: PhantomData<&'core ()>,
}
unsafe impl<'core> Send for Function<'core> {}
unsafe impl<'core> Sync for Function<'core> {}
impl<'core> Drop for Function<'core> {
#[inline]
fn drop(&mut self) {
unsafe {
API::get_cached().free_func(self.handle.as_ptr());
}
}
}
impl<'core> Clone for Function<'core> {
#[inline]
fn clone(&self) -> Self {
let handle = unsafe { API::get_cached().clone_func(self.handle.as_ptr()) };
Self {
handle: unsafe { NonNull::new_unchecked(handle) },
_owner: PhantomData,
}
}
}
impl<'core> Function<'core> {
/// Wraps `handle` in a `Function`.
///
/// # Safety
/// The caller must ensure `handle` and the lifetime are valid and API is cached.
#[inline]
pub(crate) unsafe fn from_ptr(handle: *mut ffi::VSFuncRef) -> Self {
Self {
handle: NonNull::new_unchecked(handle),
_owner: PhantomData,
}
}
/// Returns the underlying pointer.
#[inline]
pub(crate) fn ptr(&self) -> *mut ffi::VSFuncRef {
self.handle.as_ptr()
}
/// Creates a new function.
///
/// To indicate an error from the callback, set an error on the output map.
#[inline]
pub fn new<F>(api: API, core: CoreRef<'core>, callback: F) -> Self
where
F: Fn(API, CoreRef<'core>, &Map<'core>, &mut Map<'core>) + Send + Sync + 'core,
{
unsafe extern "system" fn c_callback<'core, F>(
in_: *const ffi::VSMap,
out: *mut ffi::VSMap,
user_data: *mut c_void,
core: *mut ffi::VSCore,
_vsapi: *const ffi::VSAPI,
) where
F: Fn(API, CoreRef<'core>, &Map<'core>, &mut Map<'core>) + Send + Sync + 'core,
{
let closure = move || {
let api = API::get_cached();
let core = CoreRef::from_ptr(core);
let in_ = MapRef::from_ptr(in_);
let mut out = MapRefMut::from_ptr(out);
let callback = Box::from_raw(user_data as *mut F);
callback(api, core, &in_, &mut out);
mem::forget(callback);
};
if panic::catch_unwind(closure).is_err() {
process::abort();
}
}
unsafe extern "system" fn c_free<F>(user_data: *mut c_void) {
drop(Box::from_raw(user_data as *mut F))
}
let data = Box::new(callback);
let handle = unsafe {
API::get_cached().create_func(
c_callback::<'core, F>,
Box::into_raw(data) as _,
Some(c_free::<F>),
core.ptr(),
)
};
Self {
handle: unsafe { NonNull::new_unchecked(handle) },
_owner: PhantomData,
}
}
/// Calls the function. If the call fails `out` will have an error set.
#[inline]
pub fn call(&self, in_: &Map<'core>, out: &mut Map<'core>) {
unsafe { API::get_cached().call_func(self.handle.as_ptr(), in_.deref(), out.deref_mut()) };
}
}