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// 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 crate::Display;
use crate::Surface;
use crate::SurfaceMemoryDescriptor;
use crate::VaError;
use crate::bindings;
use crate::va_check;
/// Wrapper around `VAImage` that is tied to the lifetime of a given `Picture`.
///
/// An image is used to either get the surface data to client memory, or to copy image data in
/// client memory to a surface.
pub struct Image<'a> {
/// The display from which the image was created, so we can unmap it upon destruction.
display: Arc<Display>,
/// The `VAImage` returned by libva.
image: bindings::VAImage,
/// The mapped surface data.
///
/// The lifetime also allows us to ensure that the `Surface` we have been created from
/// does not drop or get changed while we exist.
data: &'a mut [u8],
/// Whether the image was derived using the `vaDeriveImage` API or created using the
/// `vaCreateImage` API.
derived: bool,
/// The display resolution requested by the client. The implementation is
/// free to enlarge this value as needed. In any case, we guarantee that an
/// image at least as large is returned.
display_resolution: (u32, u32),
/// Tracks whether the underlying data has possibly been written to, i.e. an encoder will create
/// an image and map its buffer in order to write to it, so we must writeback later.
dirty: bool,
/// The ID of the `Surface` we have been created from.
surface_id: u32,
}
impl<'a> Image<'a> {
/// Helper method to map a `VAImage` using `vaMapBuffer` and return an `Image`.
///
/// Returns an error if the mapping failed.
fn new<D: SurfaceMemoryDescriptor>(
surface: &'a Surface<D>,
image: bindings::VAImage,
derived: bool,
display_resolution: (u32, u32),
) -> Result<Self, VaError> {
let mut addr = std::ptr::null_mut();
// Safe since `picture.inner.context` represents a valid `VAContext` and `image` has been
// successfully created at this point.
match va_check(unsafe {
crate::va::vaMapBuffer(surface.display().handle(), image.buf, &mut addr)
}) {
Ok(_) => {
// Assert that libva provided us with a coded resolution that is
// at least as large as `display_resolution`.
assert!(u32::from(image.width) >= display_resolution.0);
assert!(u32::from(image.height) >= display_resolution.1);
// Safe since `addr` points to data mapped onto our address space since we called
// `vaMapBuffer` above, which also guarantees that the data is valid for
// `image.data_size`.
let data =
unsafe { std::slice::from_raw_parts_mut(addr as _, image.data_size as usize) };
Ok(Image {
display: Arc::clone(surface.display()),
image,
data,
derived,
display_resolution,
dirty: false,
surface_id: surface.id(),
})
}
Err(e) => {
// Safe because `picture.inner.context` represents a valid `VAContext` and `image`
// represents a valid `VAImage`.
unsafe {
crate::va::vaDestroyImage(surface.display().handle(), image.image_id);
}
Err(e)
}
}
}
/// Create a new derived image from this `surface` using `vaDeriveImage`.
///
/// Derived images are a direct view (i.e. without any copy) on the buffer content of
/// `surface`. On the other hand, not all `Surface`s can be derived.
///
/// `visible_rect` is the visible rectangle inside `surface` that we want to access.
pub fn derive_from<D: SurfaceMemoryDescriptor>(
surface: &'a Surface<D>,
visible_rect: (u32, u32),
) -> Result<Self, VaError> {
// An all-zero byte-pattern is a valid initial value for `VAImage`.
let mut image: bindings::VAImage = Default::default();
// Safe because `self` has a valid display handle and ID.
va_check(unsafe {
crate::va::vaDeriveImage(surface.display().handle(), surface.id(), &mut image)
})?;
Self::new(surface, image, true, visible_rect)
}
/// Create new image from `surface` using `vaCreateImage` and `vaGetImage`.
///
/// `visible_rect` is the visible rectangle inside `surface` that we want to access.
///
/// The image will contain a copy of `surface`'s data' in the desired `format` and
/// `coded_resolution`, meaning the data can be scaled if `coded_resolution` and `visible_rect`
/// differ.
pub fn create_from<D: SurfaceMemoryDescriptor>(
surface: &'a Surface<D>,
mut format: bindings::VAImageFormat,
coded_resolution: (u32, u32),
visible_rect: (u32, u32),
) -> Result<Image<'a>, VaError> {
// An all-zero byte-pattern is a valid initial value for `VAImage`.
let mut image: bindings::VAImage = Default::default();
let dpy = surface.display().handle();
// Safe because `dpy` is a valid display handle.
va_check(unsafe {
crate::va::vaCreateImage(
dpy,
&mut format,
coded_resolution.0 as i32,
coded_resolution.1 as i32,
&mut image,
)
})?;
// Safe because `dpy` is a valid display handle, `picture.surface` is a valid VASurface and
// `image` is a valid `VAImage`.
match va_check(unsafe {
crate::va::vaGetImage(
dpy,
surface.id(),
0,
0,
coded_resolution.0,
coded_resolution.1,
image.image_id,
)
}) {
Ok(()) => Self::new(surface, image, false, visible_rect),
Err(e) => {
// Safe because `image` is a valid `VAImage`.
unsafe {
crate::va::vaDestroyImage(dpy, image.image_id);
}
Err(e)
}
}
}
/// Get a reference to the underlying `VAImage` that describes this image.
pub fn image(&self) -> &bindings::VAImage {
&self.image
}
/// Returns whether this image is directly derived from its underlying `Picture`, as opposed to
/// being a view/copy of said `Picture` in a guaranteed pixel format.
pub fn is_derived(&self) -> bool {
self.derived
}
/// Returns the display resolution as passed in by the client. This is a
/// value that is less than or equal to the coded resolution.
pub fn display_resolution(&self) -> (u32, u32) {
self.display_resolution
}
/// Returns the coded resolution. This value can be larger than the value
/// passed in when the image was created if the driver needs to.
pub fn coded_resolution(&self) -> (u32, u32) {
(self.image.width.into(), self.image.height.into())
}
}
impl<'a> AsRef<[u8]> for Image<'a> {
fn as_ref(&self) -> &[u8] {
self.data
}
}
impl<'a> AsMut<[u8]> for Image<'a> {
fn as_mut(&mut self) -> &mut [u8] {
self.dirty = true;
self.data
}
}
impl<'a> Drop for Image<'a> {
fn drop(&mut self) {
if !self.derived && self.dirty {
// Safe because `picture.inner.context` represents a valid `VAContext`,
// `picture.surface` represents a valid `VASurface` and `image` represents a valid
// `VAImage`.
unsafe {
crate::va::vaPutImage(
self.display.handle(),
self.surface_id,
self.image.image_id,
0,
0,
self.image.width as u32,
self.image.height as u32,
0,
0,
self.image.width as u32,
self.image.height as u32,
);
}
}
unsafe {
// Safe since the buffer is mapped in `Image::new`, so `self.image.buf` points to a
// valid `VABufferID`.
crate::va::vaUnmapBuffer(self.display.handle(), self.image.buf);
// Safe since `self.image` represents a valid `VAImage`.
crate::va::vaDestroyImage(self.display.handle(), self.image.image_id);
}
}
}