chore: vendor trimmed v4l2r capture crate

libs/v4l2r/src/memory/mmap.rs

@@ -0,0 +1,58 @@
+//! Operations specific to MMAP-type buffers.
+use super::*;
+use crate::{bindings, ioctl};
+use std::fmt::Debug;
+use std::os::fd::AsFd;
+
+#[derive(Default)]
+pub struct Mmap;
+
+impl Memory for Mmap {
+    const MEMORY_TYPE: MemoryType = MemoryType::Mmap;
+    type RawBacking = u32;
+
+    unsafe fn get_plane_buffer_backing(
+        m: &bindings::v4l2_plane__bindgen_ty_1,
+    ) -> &Self::RawBacking {
+        &m.mem_offset
+    }
+
+    unsafe fn get_single_planar_buffer_backing(
+        m: &bindings::v4l2_buffer__bindgen_ty_1,
+    ) -> &Self::RawBacking {
+        &m.offset
+    }
+
+    unsafe fn get_plane_buffer_backing_mut(
+        m: &mut bindings::v4l2_plane__bindgen_ty_1,
+    ) -> &mut Self::RawBacking {
+        &mut m.mem_offset
+    }
+
+    unsafe fn get_single_planar_buffer_backing_mut(
+        m: &mut bindings::v4l2_buffer__bindgen_ty_1,
+    ) -> &mut Self::RawBacking {
+        &mut m.offset
+    }
+}
+
+impl SelfBacked for Mmap {}
+
+/// Dummy handle for a MMAP plane, to use with APIs that require handles. MMAP
+/// buffers are backed by the device, and thus we don't need to attach any extra
+/// information to them.
+#[derive(Default, Debug, Clone)]
+pub struct MmapHandle;
+
+// There is no information to fill with MMAP buffers ; the index is enough.
+impl PlaneHandle for MmapHandle {
+    type Memory = Mmap;
+
+    fn fill_v4l2_plane(&self, _plane: &mut bindings::v4l2_plane) {}
+}
+
+impl Mappable for MmapHandle {
+    fn map<D: AsFd>(device: &D, plane_info: &QueryBufPlane) -> Option<PlaneMapping> {
+        ioctl::mmap(device, plane_info.mem_offset, plane_info.length).ok()
+    }
+}