1 files changed, 90 insertions, 0 deletions
diff --git a/third_party/rust/alsa/src/device_name.rs b/third_party/rust/alsa/src/device_name.rs
new file mode 100644
index 0000000000..965231e1a0
--- /dev/null
+++ b/third_party/rust/alsa/src/device_name.rs
@@ -0,0 +1,90 @@
+//! Enumerate devices in the alsa library configuration
+//!
+//! # Example
+//! Print all devices found in various categories.
+//!
+//! ```
+//! use std::ffi::CString;
+//! use alsa::device_name::HintIter;
+//!
+//! for t in &["pcm", "ctl", "rawmidi", "timer", "seq", "hwdep"] {
+//!     println!("{} devices:", t);
+//!     let i = HintIter::new(None, &*CString::new(*t).unwrap()).unwrap();
+//!     for a in i { println!("  {:?}", a) }
+//! }
+//! ```
+
+use std::ptr;
+use libc::{c_void, c_int};
+use crate::alsa;
+use super::{Card, Direction};
+use super::error::*;
+use std::ffi::{CStr, CString};
+
+/// [snd_device_name_hint](http://www.alsa-project.org/alsa-doc/alsa-lib/group___control.html) wrapper
+pub struct HintIter(*mut *mut c_void, isize);
+
+impl Drop for HintIter {
+    fn drop(&mut self) { unsafe { alsa::snd_device_name_free_hint(self.0); }}
+}
+
+impl HintIter {
+    /// typical interfaces are: "pcm", "ctl", "rawmidi", "timer", "seq" and "hwdep".
+    pub fn new(card: Option<&Card>, iface: &CStr) -> Result<HintIter> {
+        let mut p = ptr::null_mut();
+        let cnr = card.map(|c| c.get_index()).unwrap_or(-1) as c_int;
+        acheck!(snd_device_name_hint(cnr, iface.as_ptr(), &mut p))
+            .map(|_| HintIter(p, 0))
+    }
+
+    /// A constructor variant that takes the interface as a Rust string slice.
+    pub fn new_str(card: Option<&Card>, iface: &str) -> Result<HintIter> {
+        HintIter::new(card, &CString::new(iface).unwrap())
+    }
+}
+
+impl Iterator for HintIter {
+    type Item = Hint;
+    fn next(&mut self) -> Option<Hint> {
+        if self.0.is_null() { return None; }
+        let p = unsafe { *self.0.offset(self.1) };
+        if p.is_null() { return None; }
+        self.1 += 1;
+        Some(Hint::new(p))
+    }
+}
+
+
+/// [snd_device_name_get_hint](http://www.alsa-project.org/alsa-doc/alsa-lib/group___control.html) wrapper
+#[derive(Debug, Clone)]
+pub struct Hint {
+    pub name: Option<String>,
+    pub desc: Option<String>,
+    pub direction: Option<Direction>,
+}
+
+impl Hint {
+    fn get_str(p: *const c_void, name: &str) -> Option<String> {
+        let name = CString::new(name).unwrap();
+        let c = unsafe { alsa::snd_device_name_get_hint(p, name.as_ptr()) };
+        from_alloc("snd_device_name_get_hint", c).ok()
+    }
+
+    fn new(p: *const c_void) -> Hint {
+       let d = Hint::get_str(p, "IOID").and_then(|x| match &*x {
+            "Input" => Some(Direction::Capture),
+            "Output" => Some(Direction::Playback),
+            _ => None,
+       });
+       Hint { name: Hint::get_str(p, "NAME"), desc: Hint::get_str(p, "DESC"), direction: d }
+    }
+}
+
+#[test]
+fn print_hints() {
+    for t in &["pcm", "ctl", "rawmidi", "timer", "seq", "hwdep"] {
+        println!("{} devices:", t);
+        let i = HintIter::new(None, &*CString::new(*t).unwrap()).unwrap();
+        for a in i { println!("  {:?}", a) }
+    }
+}