chore: vendor trimmed v4l2r capture crate

libs/v4l2r/src/ioctl/querycap.rs

@@ -0,0 +1,136 @@
+//! Safe wrapper for the `VIDIOC_QUERYCAP` ioctl.
+use super::string_from_cstr;
+use crate::bindings;
+use crate::bindings::v4l2_capability;
+use bitflags::bitflags;
+use nix::errno::Errno;
+use std::fmt;
+use std::os::unix::io::AsRawFd;
+use thiserror::Error;
+
+bitflags! {
+    /// Flags returned by the `VIDIOC_QUERYCAP` ioctl into the `capabilities`
+    /// or `device_capabilities` field of `v4l2_capability`.
+    #[derive(Clone, Copy, Debug)]
+    pub struct Capabilities: u32 {
+        const VIDEO_CAPTURE = bindings::V4L2_CAP_VIDEO_CAPTURE;
+        const VIDEO_OUTPUT = bindings::V4L2_CAP_VIDEO_OUTPUT;
+        const VIDEO_OVERLAY = bindings::V4L2_CAP_VIDEO_OVERLAY;
+        const VBI_CAPTURE = bindings::V4L2_CAP_VBI_CAPTURE;
+        const VBI_OUTPUT = bindings::V4L2_CAP_VBI_OUTPUT;
+        const SLICED_VBI_CAPTURE = bindings::V4L2_CAP_SLICED_VBI_CAPTURE;
+        const SLICED_VBI_OUTPUT = bindings::V4L2_CAP_SLICED_VBI_OUTPUT;
+        const RDS_CAPTURE = bindings::V4L2_CAP_RDS_CAPTURE;
+        const VIDEO_OUTPUT_OVERLAY = bindings::V4L2_CAP_VIDEO_OUTPUT_OVERLAY;
+        const HW_FREQ_SEEK = bindings::V4L2_CAP_HW_FREQ_SEEK;
+        const RDS_OUTPUT = bindings::V4L2_CAP_RDS_OUTPUT;
+
+        const VIDEO_CAPTURE_MPLANE = bindings::V4L2_CAP_VIDEO_CAPTURE_MPLANE;
+        const VIDEO_OUTPUT_MPLANE = bindings::V4L2_CAP_VIDEO_OUTPUT_MPLANE;
+        const VIDEO_M2M_MPLANE = bindings::V4L2_CAP_VIDEO_M2M_MPLANE;
+        const VIDEO_M2M = bindings::V4L2_CAP_VIDEO_M2M;
+
+        const TUNER = bindings::V4L2_CAP_TUNER;
+        const AUDIO = bindings::V4L2_CAP_AUDIO;
+        const RADIO = bindings::V4L2_CAP_RADIO;
+        const MODULATOR = bindings::V4L2_CAP_MODULATOR;
+
+        const SDR_CAPTURE = bindings::V4L2_CAP_SDR_CAPTURE;
+        const EXT_PIX_FORMAT = bindings::V4L2_CAP_EXT_PIX_FORMAT;
+        const SDR_OUTPUT = bindings::V4L2_CAP_SDR_OUTPUT;
+        const META_CAPTURE = bindings::V4L2_CAP_META_CAPTURE;
+
+        const READWRITE = bindings::V4L2_CAP_READWRITE;
+        const ASYNCIO = bindings::V4L2_CAP_ASYNCIO;
+        const STREAMING = bindings::V4L2_CAP_STREAMING;
+        const META_OUTPUT = bindings::V4L2_CAP_META_OUTPUT;
+
+        const TOUCH = bindings::V4L2_CAP_TOUCH;
+
+        const DEVICE_CAPS = bindings::V4L2_CAP_DEVICE_CAPS;
+    }
+}
+
+impl fmt::Display for Capabilities {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Debug::fmt(self, f)
+    }
+}
+
+/// Used to get the capability flags from a `VIDIOC_QUERYCAP` ioctl.
+impl From<v4l2_capability> for Capabilities {
+    fn from(qcap: v4l2_capability) -> Self {
+        Capabilities::from_bits_truncate(qcap.capabilities)
+    }
+}
+
+/// Safe variant of the `v4l2_capability` struct, to be used with `querycap`.
+#[derive(Debug)]
+pub struct Capability {
+    pub driver: String,
+    pub card: String,
+    pub bus_info: String,
+    pub version: u32,
+    pub capabilities: Capabilities,
+    pub device_caps: Option<Capabilities>,
+}
+
+impl Capability {
+    /// Returns the set of capabilities of the hardware as a whole.
+    pub fn capabilities(&self) -> Capabilities {
+        self.capabilities
+    }
+
+    /// Returns the capabilities that apply to the currently opened V4L2 node.
+    pub fn device_caps(&self) -> Capabilities {
+        self.device_caps
+            .unwrap_or_else(|| self.capabilities.difference(Capabilities::DEVICE_CAPS))
+    }
+}
+
+impl From<v4l2_capability> for Capability {
+    fn from(qcap: v4l2_capability) -> Self {
+        Capability {
+            driver: string_from_cstr(&qcap.driver).unwrap_or_else(|_| "".into()),
+            card: string_from_cstr(&qcap.card).unwrap_or_else(|_| "".into()),
+            bus_info: string_from_cstr(&qcap.bus_info).unwrap_or_else(|_| "".into()),
+            version: qcap.version,
+            capabilities: Capabilities::from_bits_truncate(qcap.capabilities),
+            device_caps: if qcap.capabilities & bindings::V4L2_CAP_DEVICE_CAPS != 0 {
+                Some(Capabilities::from_bits_truncate(qcap.device_caps))
+            } else {
+                None
+            },
+        }
+    }
+}
+
+#[doc(hidden)]
+mod ioctl {
+    use crate::bindings::v4l2_capability;
+    nix::ioctl_read!(vidioc_querycap, b'V', 0, v4l2_capability);
+}
+
+#[derive(Debug, Error)]
+pub enum QueryCapError {
+    #[error("ioctl error: {0}")]
+    IoctlError(Errno),
+}
+
+impl From<QueryCapError> for Errno {
+    fn from(err: QueryCapError) -> Self {
+        match err {
+            QueryCapError::IoctlError(e) => e,
+        }
+    }
+}
+
+/// Safe wrapper around the `VIDIOC_QUERYCAP` ioctl.
+pub fn querycap<T: From<v4l2_capability>>(fd: &impl AsRawFd) -> Result<T, QueryCapError> {
+    let mut qcap: v4l2_capability = Default::default();
+
+    match unsafe { ioctl::vidioc_querycap(fd.as_raw_fd(), &mut qcap) } {
+        Ok(_) => Ok(T::from(qcap)),
+        Err(e) => Err(QueryCapError::IoctlError(e)),
+    }
+}