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 std::sync::Arc;

use log::error;
use thiserror::Error;

use crate::bindings;
use crate::display::Display;
use crate::generic_value::GenericValue;
use crate::va_check;
use crate::GenericValueError;
use crate::VaError;

/// A configuration for a given [`Display`].
pub struct Config {
	display: Arc<Display>,
	id: bindings::VAConfigID,
}

#[derive(Debug, Error)]
pub enum QuerySurfaceAttributesError {
	#[error("error while calling vaQuerySurfaceAttributes: {0}")]
	VaError(#[from] VaError),
	#[error("error while converting attribute: {0}")]
	GenericValueError(#[from] GenericValueError),
}

impl Config {
	/// Creates a Config by wrapping around the `vaCreateConfig` call. This is just a helper for
	/// [`Display::create_config`].
	pub(crate) fn new(
		display: Arc<Display>,
		mut attrs: Vec<bindings::VAConfigAttrib>,
		profile: bindings::VAProfile::Type,
		entrypoint: bindings::VAEntrypoint::Type,
	) -> Result<Self, VaError> {
		let mut config_id = 0u32;

		// Safe because `self` represents a valid `VADisplay`.
		//
		// The `attrs` vector is also properly initialized and its actual size is passed to
		// `vaCreateConfig`, so it is impossible to write past the end of its storage by mistake.
		va_check(unsafe {
			bindings::vaCreateConfig(
				display.handle(),
				profile,
				entrypoint,
				attrs.as_mut_ptr(),
				attrs.len() as i32,
				&mut config_id,
			)
		})?;

		Ok(Self { display, id: config_id })
	}

	/// Returns the ID of this config.
	pub(crate) fn id(&self) -> bindings::VAConfigID {
		self.id
	}

	// Queries surface attributes for this config.
	//
	// This function queries for all supported attributes for this configuration. In particular, if
	// the underlying hardware supports the creation of VA surfaces in various formats, then this
	// function will enumerate all pixel formats that are supported.
	fn query_surface_attributes(&mut self) -> Result<Vec<bindings::VASurfaceAttrib>, VaError> {
		// Safe because `self` represents a valid VAConfig. We first query how
		// much space is needed by the C API by passing in NULL in the first
		// call to `vaQuerySurfaceAttributes`.
		let attrs_len: std::os::raw::c_uint = 0;
		va_check(unsafe {
			bindings::vaQuerySurfaceAttributes(
				self.display.handle(),
				self.id,
				std::ptr::null_mut(),
				&attrs_len as *const _ as *mut std::os::raw::c_uint,
			)
		})?;

		let mut attrs = Vec::with_capacity(attrs_len as usize);
		// Safe because we allocate a vector with the required capacity as
		// returned by the initial call to vaQuerySurfaceAttributes. We then
		// pass a valid pointer to it.
		va_check(unsafe {
			bindings::vaQuerySurfaceAttributes(
				self.display.handle(),
				self.id,
				attrs.as_mut_ptr(),
				&attrs_len as *const _ as *mut std::os::raw::c_uint,
			)
		})?;

		// Safe because vaQuerySurfaceAttributes will have written to
		// exactly attrs_len entries in the vector.
		unsafe {
			attrs.set_len(attrs_len as usize);
		}

		Ok(attrs)
	}

	/// Query the surface attributes of type `attr_type`. The attribute may or may not be defined by
	/// the driver.
	pub fn query_surface_attributes_by_type(
		&mut self,
		attr_type: bindings::VASurfaceAttribType::Type,
	) -> Result<Vec<GenericValue>, QuerySurfaceAttributesError> {
		let surface_attributes = self.query_surface_attributes()?;

		surface_attributes
			.into_iter()
			.filter(|attr| attr.type_ == attr_type)
			.map(|attr| GenericValue::try_from(attr.value).map_err(QuerySurfaceAttributesError::GenericValueError))
			.collect()
	}
}

impl Drop for Config {
	fn drop(&mut self) {
		// Safe because `self` represents a valid Config.
		let status = va_check(unsafe { bindings::vaDestroyConfig(self.display.handle(), self.id) });

		if status.is_err() {
			error!("vaDestroyConfig failed: {}", status.unwrap_err());
		}
	}
}