Allow Display to be used by multiple threads

lib/src/config.rs

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-use std::rc::Rc;
+use std::sync::Arc;
 
 use log::error;
 use thiserror::Error;
@@ -16,7 +16,7 @@ use crate::VaError;
 
 /// A configuration for a given [`Display`].
 pub struct Config {
-    display: Rc<Display>,
+    display: Arc<Display>,
     id: bindings::VAConfigID,
 }
 
@@ -32,7 +32,7 @@ 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: Rc<Display>,
+        display: Arc<Display>,
         mut attrs: Vec<bindings::VAConfigAttrib>,
         profile: bindings::VAProfile::Type,
         entrypoint: bindings::VAEntrypoint::Type,

lib/src/context.rs

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 use std::rc::Rc;
+use std::sync::Arc;
 
 use log::error;
 
@@ -19,15 +20,15 @@ use crate::VaError;
 
 /// A VA context for a particular [`Display`].
 pub struct Context {
-    display: Rc<Display>,
+    display: Arc<Display>,
     id: bindings::VAContextID,
 }
 
 impl Context {
     /// Creates a Context by wrapping around a `vaCreateContext` call. This is just a helper for
     /// [`Display::create_context`].
     pub(crate) fn new<D: SurfaceMemoryDescriptor>(
-        display: Rc<Display>,
+        display: Arc<Display>,
         config: &Config,
         coded_width: u32,
         coded_height: u32,
@@ -69,7 +70,7 @@ impl Context {
     }
 
     /// Returns a shared reference to the [`Display`] used by this context.
-    pub fn display(&self) -> &Rc<Display> {
+    pub fn display(&self) -> &Arc<Display> {
         &self.display
     }
 

lib/src/display.rs

@@ -9,6 +9,7 @@ use std::os::unix::io::AsRawFd;
 use std::path::Path;
 use std::path::PathBuf;
 use std::rc::Rc;
+use std::sync::Arc;
 
 use thiserror::Error;
 
@@ -92,7 +93,7 @@ impl Display {
     /// Opens and initializes a specific DRM `Display`.
     ///
     /// `path` is the path to a DRM device that supports VAAPI, e.g. `/dev/dri/renderD128`.
-    pub fn open_drm_display<P: AsRef<Path>>(path: P) -> Result<Rc<Self>, OpenDrmDisplayError> {
+    pub fn open_drm_display<P: AsRef<Path>>(path: P) -> Result<Arc<Self>, OpenDrmDisplayError> {
         let file = std::fs::File::options()
             .read(true)
             .write(true)
@@ -112,7 +113,7 @@ impl Display {
         // vaInitialize. The File will close the DRM fd on drop.
         va_check(unsafe { bindings::vaInitialize(display, &mut major, &mut minor) })
             .map(|()| {
-                Rc::new(Self {
+                Arc::new(Self {
                     handle: display,
                     drm_file: file,
                 })
@@ -124,7 +125,7 @@ impl Display {
     ///
     /// If an error occurs on a given device, it is ignored and the next one is tried until one
     /// succeeds or we reach the end of the iterator.
-    pub fn open() -> Option<Rc<Self>> {
+    pub fn open() -> Option<Arc<Self>> {
         let devices = DrmDeviceIterator::default();
 
         // Try all the DRM devices until one succeeds.
@@ -263,7 +264,7 @@ impl Display {
     /// case of error the `descriptors` will be destroyed. Make sure to duplicate the descriptors
     /// if you need something outside of libva to access them.
     pub fn create_surfaces<D: SurfaceMemoryDescriptor>(
-        self: &Rc<Self>,
+        self: &Arc<Self>,
         rt_format: u32,
         va_fourcc: Option<u32>,
         width: u32,
@@ -272,7 +273,7 @@ impl Display {
         descriptors: Vec<D>,
     ) -> Result<Vec<Surface<D>>, VaError> {
         Surface::new(
-            Rc::clone(self),
+            Arc::clone(self),
             rt_format,
             va_fourcc,
             width,
@@ -292,15 +293,15 @@ impl Display {
     /// * `surfaces` - Optional hint for the amount of surfaces tied to the context
     /// * `progressive` - Whether only progressive frame pictures are present in the sequence
     pub fn create_context<D: SurfaceMemoryDescriptor>(
-        self: &Rc<Self>,
+        self: &Arc<Self>,
         config: &Config,
         coded_width: u32,
         coded_height: u32,
         surfaces: Option<&Vec<Surface<D>>>,
         progressive: bool,
     ) -> Result<Rc<Context>, VaError> {
         Context::new(
-            Rc::clone(self),
+            Arc::clone(self),
             config,
             coded_width,
             coded_height,
@@ -316,12 +317,12 @@ impl Display {
     /// [`Display::get_config_attributes`]. Other attributes will take their default values, and
     /// `attrs` can be empty in order to obtain a default configuration.
     pub fn create_config(
-        self: &Rc<Self>,
+        self: &Arc<Self>,
         attrs: Vec<bindings::VAConfigAttrib>,
         profile: bindings::VAProfile::Type,
         entrypoint: bindings::VAEntrypoint::Type,
     ) -> Result<Config, VaError> {
-        Config::new(Rc::clone(self), attrs, profile, entrypoint)
+        Config::new(Arc::clone(self), attrs, profile, entrypoint)
     }
 
     /// Returns available image formats for this display by wrapping around `vaQueryImageFormats`.
@@ -360,3 +361,8 @@ impl Drop for Display {
         }
     }
 }
+
+// Safe because because it only contains a `File` (which is Send+Sync), and a VADisplay handle
+// which is also thread-safe. The Drop handler can also be safely called from any thread.
+unsafe impl Send for Display {}
+unsafe impl Sync for Display {}

lib/src/image.rs

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-use std::rc::Rc;
+use std::sync::Arc;
 
 use crate::bindings;
 use crate::va_check;
@@ -17,7 +17,7 @@ use crate::VaError;
 /// 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: Rc<Display>,
+    display: Arc<Display>,
     /// The `VAImage` returned by libva.
     image: bindings::VAImage,
     /// The mapped surface data.
@@ -68,7 +68,7 @@ impl<'a> Image<'a> {
                 let data =
                     unsafe { std::slice::from_raw_parts_mut(addr as _, image.data_size as usize) };
                 Ok(Image {
-                    display: Rc::clone(surface.display()),
+                    display: Arc::clone(surface.display()),
                     image,
                     data,
                     derived,

lib/src/surface.rs

@@ -6,7 +6,7 @@ use std::any::Any;
 use std::os::fd::FromRawFd;
 use std::os::fd::OwnedFd;
 use std::os::raw::c_void;
-use std::rc::Rc;
+use std::sync::Arc;
 
 use crate::bindings;
 use crate::display::Display;
@@ -122,7 +122,7 @@ pub struct SurfaceDecodeMBError {
 
 /// An owned VA surface that is tied to a particular `Display`.
 pub struct Surface<D: SurfaceMemoryDescriptor> {
-    display: Rc<Display>,
+    display: Arc<Display>,
     id: bindings::VASurfaceID,
     descriptor: D,
     width: u32,
@@ -195,7 +195,7 @@ impl<D: SurfaceMemoryDescriptor> Surface<D> {
     /// Create `Surfaces` by wrapping around a `vaCreateSurfaces` call. This is just a helper for
     /// [`Display::create_surfaces`].
     pub(crate) fn new(
-        display: Rc<Display>,
+        display: Arc<Display>,
         rt_format: u32,
         va_fourcc: Option<u32>,
         width: u32,
@@ -239,7 +239,7 @@ impl<D: SurfaceMemoryDescriptor> Surface<D> {
                 )
             }) {
                 Ok(()) => surfaces.push(Self {
-                    display: Rc::clone(&display),
+                    display: Arc::clone(&display),
                     id: surface_id,
                     descriptor,
                     width,
@@ -252,7 +252,7 @@ impl<D: SurfaceMemoryDescriptor> Surface<D> {
         Ok(surfaces)
     }
 
-    pub(crate) fn display(&self) -> &Rc<Display> {
+    pub(crate) fn display(&self) -> &Arc<Display> {
         &self.display
     }