1 //! Safe wrapper for the `VIDIOC_QUERYCAP` ioctl.
2 use super::string_from_cstr;
3 use crate::bindings;
4 use crate::bindings::v4l2_capability;
5 use bitflags::bitflags;
6 use nix::errno::Errno;
7 use std::fmt;
8 use std::os::unix::io::AsRawFd;
9 use thiserror::Error;
10
11 bitflags! {
12 /// Flags returned by the `VIDIOC_QUERYCAP` ioctl into the `capabilities`
13 /// or `device_capabilities` field of `v4l2_capability`.
14 #[derive(Clone, Copy, Debug)]
15 pub struct Capabilities: u32 {
16 const VIDEO_CAPTURE = bindings::V4L2_CAP_VIDEO_CAPTURE;
17 const VIDEO_OUTPUT = bindings::V4L2_CAP_VIDEO_OUTPUT;
18 const VIDEO_OVERLAY = bindings::V4L2_CAP_VIDEO_OVERLAY;
19 const VBI_CAPTURE = bindings::V4L2_CAP_VBI_CAPTURE;
20 const VBI_OUTPUT = bindings::V4L2_CAP_VBI_OUTPUT;
21 const SLICED_VBI_CAPTURE = bindings::V4L2_CAP_SLICED_VBI_CAPTURE;
22 const SLICED_VBI_OUTPUT = bindings::V4L2_CAP_SLICED_VBI_OUTPUT;
23 const RDS_CAPTURE = bindings::V4L2_CAP_RDS_CAPTURE;
24 const VIDEO_OUTPUT_OVERLAY = bindings::V4L2_CAP_VIDEO_OUTPUT_OVERLAY;
25 const HW_FREQ_SEEK = bindings::V4L2_CAP_HW_FREQ_SEEK;
26 const RDS_OUTPUT = bindings::V4L2_CAP_RDS_OUTPUT;
27
28 const VIDEO_CAPTURE_MPLANE = bindings::V4L2_CAP_VIDEO_CAPTURE_MPLANE;
29 const VIDEO_OUTPUT_MPLANE = bindings::V4L2_CAP_VIDEO_OUTPUT_MPLANE;
30 const VIDEO_M2M_MPLANE = bindings::V4L2_CAP_VIDEO_M2M_MPLANE;
31 const VIDEO_M2M = bindings::V4L2_CAP_VIDEO_M2M;
32
33 const TUNER = bindings::V4L2_CAP_TUNER;
34 const AUDIO = bindings::V4L2_CAP_AUDIO;
35 const RADIO = bindings::V4L2_CAP_RADIO;
36 const MODULATOR = bindings::V4L2_CAP_MODULATOR;
37
38 const SDR_CAPTURE = bindings::V4L2_CAP_SDR_CAPTURE;
39 const EXT_PIX_FORMAT = bindings::V4L2_CAP_EXT_PIX_FORMAT;
40 const SDR_OUTPUT = bindings::V4L2_CAP_SDR_OUTPUT;
41 const META_CAPTURE = bindings::V4L2_CAP_META_CAPTURE;
42
43 const READWRITE = bindings::V4L2_CAP_READWRITE;
44 const ASYNCIO = bindings::V4L2_CAP_ASYNCIO;
45 const STREAMING = bindings::V4L2_CAP_STREAMING;
46 const META_OUTPUT = bindings::V4L2_CAP_META_OUTPUT;
47
48 const TOUCH = bindings::V4L2_CAP_TOUCH;
49
50 const DEVICE_CAPS = bindings::V4L2_CAP_DEVICE_CAPS;
51 }
52 }
53
54 impl fmt::Display for Capabilities {
fmt(&self, f: &mut fmt::Formatter) -> fmt::Result55 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
56 fmt::Debug::fmt(self, f)
57 }
58 }
59
60 /// Used to get the capability flags from a `VIDIOC_QUERYCAP` ioctl.
61 impl From<v4l2_capability> for Capabilities {
from(qcap: v4l2_capability) -> Self62 fn from(qcap: v4l2_capability) -> Self {
63 Capabilities::from_bits_truncate(qcap.capabilities)
64 }
65 }
66
67 /// Safe variant of the `v4l2_capability` struct, to be used with `querycap`.
68 #[derive(Debug)]
69 pub struct Capability {
70 pub driver: String,
71 pub card: String,
72 pub bus_info: String,
73 pub version: u32,
74 pub capabilities: Capabilities,
75 pub device_caps: Option<Capabilities>,
76 }
77
78 impl Capability {
79 /// Returns the set of capabilities of the hardware as a whole.
capabilities(&self) -> Capabilities80 pub fn capabilities(&self) -> Capabilities {
81 self.capabilities
82 }
83
84 /// Returns the capabilities that apply to the currently opened V4L2 node.
device_caps(&self) -> Capabilities85 pub fn device_caps(&self) -> Capabilities {
86 self.device_caps
87 .unwrap_or_else(|| self.capabilities.difference(Capabilities::DEVICE_CAPS))
88 }
89 }
90
91 impl From<v4l2_capability> for Capability {
from(qcap: v4l2_capability) -> Self92 fn from(qcap: v4l2_capability) -> Self {
93 Capability {
94 driver: string_from_cstr(&qcap.driver).unwrap_or_else(|_| "".into()),
95 card: string_from_cstr(&qcap.card).unwrap_or_else(|_| "".into()),
96 bus_info: string_from_cstr(&qcap.bus_info).unwrap_or_else(|_| "".into()),
97 version: qcap.version,
98 capabilities: Capabilities::from_bits_truncate(qcap.capabilities),
99 device_caps: if qcap.capabilities & bindings::V4L2_CAP_DEVICE_CAPS != 0 {
100 Some(Capabilities::from_bits_truncate(qcap.device_caps))
101 } else {
102 None
103 },
104 }
105 }
106 }
107
108 #[doc(hidden)]
109 mod ioctl {
110 use crate::bindings::v4l2_capability;
111 nix::ioctl_read!(vidioc_querycap, b'V', 0, v4l2_capability);
112 }
113
114 #[derive(Debug, Error)]
115 pub enum QueryCapError {
116 #[error("ioctl error: {0}")]
117 IoctlError(Errno),
118 }
119
120 impl From<QueryCapError> for Errno {
from(err: QueryCapError) -> Self121 fn from(err: QueryCapError) -> Self {
122 match err {
123 QueryCapError::IoctlError(e) => e,
124 }
125 }
126 }
127
128 /// Safe wrapper around the `VIDIOC_QUERYCAP` ioctl.
querycap<T: From<v4l2_capability>>(fd: &impl AsRawFd) -> Result<T, QueryCapError>129 pub fn querycap<T: From<v4l2_capability>>(fd: &impl AsRawFd) -> Result<T, QueryCapError> {
130 let mut qcap: v4l2_capability = Default::default();
131
132 match unsafe { ioctl::vidioc_querycap(fd.as_raw_fd(), &mut qcap) } {
133 Ok(_) => Ok(T::from(qcap)),
134 Err(e) => Err(QueryCapError::IoctlError(e)),
135 }
136 }
137