Make ALSA compile again

src/alsa/enumerate.rs

@@ -0,0 +1,78 @@
+use super::alsa;
+use super::check_errors;
+use super::Endpoint;
+
+use std::ffi::CStr;
+use std::mem;
+
+/// ALSA implementation for `EndpointsIterator`.
+pub struct EndpointsIterator {
+    // we keep the original list so that we can pass it to the free function
+    global_list: *const *const u8,
+
+    // pointer to the next string ; contained within `global_list`
+    next_str: *const *const u8,
+}
+
+unsafe impl Send for EndpointsIterator {}
+unsafe impl Sync for EndpointsIterator {}
+
+impl Drop for EndpointsIterator {
+    fn drop(&mut self) {
+        unsafe {
+            alsa::snd_device_name_free_hint(self.global_list as *mut _);
+        }
+    }
+}
+
+impl Default for EndpointsIterator {
+    fn default() -> EndpointsIterator {
+        unsafe {
+            let mut hints = mem::uninitialized();
+            // TODO: check in which situation this can fail
+            check_errors(alsa::snd_device_name_hint(-1, b"pcm\0".as_ptr() as *const _,
+                                                    &mut hints)).unwrap();
+
+            let hints = hints as *const *const u8;
+
+            EndpointsIterator {
+                global_list: hints,
+                next_str: hints,
+            }
+        }
+    }
+}
+
+impl Iterator for EndpointsIterator {
+    type Item = Endpoint;
+
+    fn next(&mut self) -> Option<Endpoint> {
+        loop {
+            unsafe {
+                if (*self.next_str).is_null() {
+                    return None;
+                }
+
+                let name = alsa::snd_device_name_get_hint(*self.next_str as *const _,
+                                                          b"NAME".as_ptr() as *const _);
+                self.next_str = self.next_str.offset(1);
+
+                if name.is_null() {
+                    continue;
+                }
+
+                let name = CStr::from_ptr(name).to_bytes().to_vec();
+                let name = String::from_utf8(name).unwrap();
+
+                if name != "null" {
+                    return Some(Endpoint(name));
+                }
+            }
+        }
+    }
+}
+
+pub fn get_default_endpoint() -> Option<Endpoint> {
+    // TODO: do in a different way?
+    Some(Endpoint("default".to_owned()))
+}

src/alsa/mod.rs

@@ -1,9 +1,39 @@
 extern crate alsa_sys as alsa;
 extern crate libc;
 
+pub use self::enumerate::{EndpointsIterator, get_default_endpoint};
+
+use CreationError;
+use Format;
+use FormatsEnumerationError;
+use SampleFormat;
+use SamplesRate;
+
 use std::{ffi, iter, mem};
+use std::option::IntoIter as OptionIntoIter;
 use std::sync::Mutex;
 
+pub type SupportedFormatsIterator = OptionIntoIter<Format>;
+
+mod enumerate;
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct Endpoint(String);
+
+impl Endpoint {
+    pub fn get_supported_formats_list(&self)
+            -> Result<SupportedFormatsIterator, FormatsEnumerationError>
+    {
+        let format = Format {
+            channels: 2,
+            samples_rate: SamplesRate(44100),
+            data_type: SampleFormat::I16,
+        };
+
+        Ok(Some(format).into_iter())
+    }
+}
+
 pub struct Voice {
     channel: Mutex<*mut alsa::snd_pcm_t>,
     num_channels: u16,
@@ -15,9 +45,9 @@ pub struct Buffer<'a, T> {
 }
 
 impl Voice {
-    pub fn new() -> Voice {
+    pub fn new(endpoint: &Endpoint, _format: &Format) -> Result<Voice, CreationError> {
         unsafe {
-            let name = ffi::CString::new(b"default".to_vec()).unwrap();
+            let name = ffi::CString::new(endpoint.0.clone()).unwrap();
 
             let mut playback_handle = mem::uninitialized();
             check_errors(alsa::snd_pcm_open(&mut playback_handle, name.as_ptr(), alsa::SND_PCM_STREAM_PLAYBACK, alsa::SND_PCM_NONBLOCK)).unwrap();
@@ -34,10 +64,10 @@ impl Voice {
 
             check_errors(alsa::snd_pcm_prepare(playback_handle)).unwrap();
 
-            Voice {
+            Ok(Voice {
                 channel: Mutex::new(playback_handle),
                 num_channels: 2,
-            }
+            })
         }
     }