moq-vaapi 0.0.2

// Copyright 2022 The ChromiumOS Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

use thiserror::Error;

use crate::bindings;

/// A wrapper over `VAGenericValue` giving us safe access to the underlying union members.
#[derive(Debug)]
pub enum GenericValue {
	/// A wrapper over VAGenericValueTypeInteger
	Integer(i32),
	/// A wrapper over VAGenericValueTypeFloat
	Float(f32),
	/// A wrapper over VAGenericValueTypePointer
	Pointer(*mut std::os::raw::c_void),
	/// A wrapper over VAGenericValueTypeFunc
	Func(bindings::VAGenericFunc),
}

#[derive(Debug, Error)]
pub enum GenericValueError {
	#[error("unexpected VAGenericValueType {0}")]
	UnexpectedType(u32),
}

impl TryFrom<bindings::VAGenericValue> for GenericValue {
	type Error = GenericValueError;

	fn try_from(value: bindings::VAGenericValue) -> Result<Self, Self::Error> {
		// Safe because we check the type before accessing the union.
		match value.type_ {
			// Safe because we check the type before accessing the union.
			bindings::VAGenericValueType::VAGenericValueTypeInteger => Ok(Self::Integer(unsafe { value.value.i })),
			bindings::VAGenericValueType::VAGenericValueTypeFloat => Ok(Self::Float(unsafe { value.value.f })),
			bindings::VAGenericValueType::VAGenericValueTypePointer => Ok(Self::Pointer(unsafe { value.value.p })),
			bindings::VAGenericValueType::VAGenericValueTypeFunc => Ok(Self::Func(unsafe { value.value.fn_ })),
			_ => Err(GenericValueError::UnexpectedType(value.type_)),
		}
	}
}