video: add udmabuf allocator

src/allocator.rs

@@ -0,0 +1,57 @@
+use {
+    crate::{
+        format::Format,
+        video::{
+            dmabuf::{DmaBuf, DmaBufIds},
+            drm::Drm,
+            Modifier,
+        },
+    },
+    std::{error::Error, rc::Rc},
+    thiserror::Error,
+};
+
+#[derive(Debug, Error)]
+#[error(transparent)]
+pub struct AllocatorError(#[from] pub Box<dyn Error>);
+
+bitflags! {
+    BufferUsage: u32;
+        BO_USE_SCANOUT = 1 << 0,
+        BO_USE_CURSOR = 1 << 1,
+        BO_USE_RENDERING = 1 << 2,
+        BO_USE_WRITE = 1 << 3,
+        BO_USE_LINEAR = 1 << 4,
+        BO_USE_PROTECTED = 1 << 5,
+}
+
+pub trait Allocator {
+    fn drm(&self) -> Option<&Drm>;
+    fn create_bo(
+        &self,
+        dma_buf_ids: &DmaBufIds,
+        width: i32,
+        height: i32,
+        format: &'static Format,
+        modifiers: &[Modifier],
+        usage: BufferUsage,
+    ) -> Result<Rc<dyn BufferObject>, AllocatorError>;
+    fn import_dmabuf(
+        &self,
+        dmabuf: &DmaBuf,
+        usage: BufferUsage,
+    ) -> Result<Rc<dyn BufferObject>, AllocatorError>;
+}
+
+pub trait BufferObject {
+    fn dmabuf(&self) -> &DmaBuf;
+    fn map_read(self: Rc<Self>) -> Result<Box<dyn MappedBuffer>, AllocatorError>;
+    fn map_write(self: Rc<Self>) -> Result<Box<dyn MappedBuffer>, AllocatorError>;
+}
+
+pub trait MappedBuffer {
+    unsafe fn data(&self) -> &[u8];
+    #[cfg_attr(not(test), allow(dead_code))]
+    fn data_ptr(&self) -> *mut u8;
+    fn stride(&self) -> i32;
+}