Refactor Config structs according to features

Cargo.toml

@@ -34,6 +34,7 @@ xdg = "2.2"
 librespot = { version = "0.1.1", default-features = false, features = ["with-tremor"] }
 toml = "0.5.8"
 color-eyre = "0.5"
+cfg-if = "1"
 
 [target."cfg(target_os = \"macos\")".dependencies]
 whoami = "0.9.0"

docs/src/config/File.md

@@ -42,13 +42,19 @@ backend = "alsa"
 
 # The alsa audio device to stream audio to. To get a
 # list of valid devices, run `aplay -L`,
+#
+# Comment out or remove if you are not using the `alsa_backend`.
 device = "alsa_audio_device"  # omit for macOS
 
 # The alsa control device. By default this is the same
 # name as the `device` field.
+#
+# Comment out or remove if you are not using the `alsa_backend`.
 control = "alsa_audio_device"  # omit for macOS
 
 # The alsa mixer used by `spotifyd`.
+#
+# Comment out or remove if you are not using the `alsa_backend`.
 mixer = "PCM"
 
 # The volume controller. Each one behaves different to
@@ -114,7 +120,7 @@ device_type = "speaker"
 
 - **`use_keyring`** config entry / **`--use-keyring`** CLI flag <!-- omit in toc -->
 
-  This features leverages [Linux's DBus Secret Service API][secret-storage-specification] or native macOS keychain in order to forgo the need to store your password directly in the config file. To use it, complile with the `dbus_keyring` feature and set the `use-keyring` config entry to `true` or pass the `--use-keyring` CLI flag  during start to the daemon. Remove the `password` and/or `password_cmd` config entries.
+  This features leverages [Linux's DBus Secret Service API][secret-storage-specification] or native macOS keychain in order to forgo the need to store your password directly in the config file. To use it, complile with the `dbus_keyring` feature and set the `use-keyring` config entry to `true` or pass the `--use-keyring` CLI flag during start to the daemon. Remove the `password` and/or `password_cmd` config entries.
 
   Your keyring entry needs to have the following attributes set:
 

src/config.rs

@@ -317,14 +317,17 @@ pub struct SharedConfigValues {
     volume_controller: Option<VolumeController>,
 
     /// The audio device
+    #[cfg(feature = "alsa_backend")]
     #[structopt(long, value_name = "string")]
     device: Option<String>,
 
     /// The control device
+    #[cfg(feature = "alsa_backend")]
     #[structopt(long, value_name = "string")]
     control: Option<String>,
 
     /// The mixer to use
+    #[cfg(feature = "alsa_backend")]
     #[structopt(long, value_name = "string")]
     mixer: Option<String>,
 
@@ -429,7 +432,8 @@ impl fmt::Debug for SharedConfigValues {
             None
         };
 
-        f.debug_struct("SharedConfigValues")
+        let mut deb_struct = f.debug_struct("SharedConfigValues");
+        deb_struct
             .field("username", &username_value)
             .field("username_cmd", &username_cmd_value)
             .field("password", &password_value)
@@ -441,18 +445,25 @@ impl fmt::Debug for SharedConfigValues {
             .field("no-audio-cache", &self.no_audio_cache)
             .field("backend", &self.backend)
             .field("volume_controller", &self.volume_controller)
-            .field("device", &self.device)
-            .field("control", &self.control)
-            .field("mixer", &self.mixer)
             .field("device_name", &self.device_name)
             .field("bitrate", &self.bitrate)
             .field("initial_volume", &self.initial_volume)
             .field("volume_normalisation", &self.volume_normalisation)
             .field("normalisation_pregain", &self.normalisation_pregain)
             .field("zeroconf_port", &self.zeroconf_port)
             .field("proxy", &self.proxy)
-            .field("device_type", &self.device_type)
-            .finish()
+            .field("device_type", &self.device_type);
+        cfg_if::cfg_if! {
+            if #[cfg(feature = "alsa_backend")] {
+                deb_struct
+                .field("device", &self.device)
+                .field("control", &self.control)
+                .field("mixer", &self.mixer)
+                .finish()
+            } else {
+                deb_struct.finish()
+            }
+        }
     }
 }
 
@@ -494,7 +505,6 @@ impl SharedConfigValues {
             }
         }
 
-        // Handles Option<T> merging.
         merge!(
             backend,
             username,
@@ -505,9 +515,6 @@ impl SharedConfigValues {
             bitrate,
             initial_volume,
             device_name,
-            mixer,
-            control,
-            device,
             volume_controller,
             cache_path,
             on_song_change_hook,
@@ -517,6 +524,9 @@ impl SharedConfigValues {
             use_mpris
         );
 
+        #[cfg(feature = "alsa_backend")]
+        merge!(mixer, control, device);
+
         // Handles boolean merging.
         self.use_keyring |= other.use_keyring;
         self.volume_normalisation |= other.volume_normalisation;
@@ -550,12 +560,13 @@ pub(crate) struct SpotifydConfig {
     pub(crate) use_mpris: bool,
     pub(crate) cache: Option<Cache>,
     pub(crate) backend: Option<String>,
+    #[cfg(feature = "alsa_backend")]
     pub(crate) audio_device: Option<String>,
-    #[allow(unused)]
+    #[cfg(feature = "alsa_backend")]
     pub(crate) control_device: Option<String>,
-    #[allow(unused)]
+    #[cfg(feature = "alsa_backend")]
     pub(crate) mixer: Option<String>,
-    #[allow(unused)]
+    #[cfg_attr(not(feature = "alsa_backend"), allow(dead_code))]
     pub(crate) volume_controller: VolumeController,
     pub(crate) initial_volume: Option<u16>,
     pub(crate) device_name: String,
@@ -683,8 +694,11 @@ pub(crate) fn get_internal_config(config: CliConfig) -> SpotifydConfig {
         use_mpris: config.shared_config.use_mpris.unwrap_or(true),
         cache,
         backend: Some(backend),
+        #[cfg(feature = "alsa_backend")]
         audio_device: config.shared_config.device,
+        #[cfg(feature = "alsa_backend")]
         control_device: config.shared_config.control,
+        #[cfg(feature = "alsa_backend")]
         mixer: config.shared_config.mixer,
         volume_controller,
         initial_volume,
@@ -738,4 +752,27 @@ mod tests {
         spotifyd_section.username = Some("testUserName".to_string());
         assert_eq!(merged_config, spotifyd_section);
     }
+
+    #[cfg(features = "alsa_backend")]
+    #[test]
+    fn test_section_merging() {
+        let mut spotifyd_section = SharedConfigValues::default();
+        global_section.mixer = "PCM".to_string();
+
+        let global_section = SharedConfigValues::default();
+        global_section.mixer = "PCM1".to_string();
+
+        // The test only makes sense if both sections differ.
+        assert!(spotifyd_section != global_section, true);
+
+        let file_config = FileConfig {
+            global: Some(global_section),
+            spotifyd: Some(spotifyd_section.clone()),
+        };
+        let merged_config = file_config.get_merged_sections().unwrap();
+
+        // Add the new field to spotifyd section.
+        spotifyd_section.mixer = "PMC".to_string();
+        assert_eq!(merged_config, spotifyd_section);
+    }
 }

src/setup.rs

@@ -23,12 +23,18 @@ use std::{io, process::exit};
 use tokio_core::reactor::Handle;
 use tokio_signal::ctrl_c;
 
+// We need to allow these lints since the conditional compilation is
+// what makes them appear.
+#[allow(unused_must_use, unreachable_code, unused_variables)]
 pub(crate) fn initial_state(
     handle: Handle,
     config: config::SpotifydConfig,
 ) -> main_loop::MainLoopState {
-    #[cfg(feature = "alsa_backend")]
-    let mut mixer = {
+    // We just need to initialize the mixer. The contents will be mutated for sure
+    // and therefore we don't need to worry since all of the branches are covered.
+    let mut mixer: Box<dyn FnMut() -> Box<dyn Mixer>> = unimplemented!();
+    cfg_if::cfg_if! {
+        if #[cfg(feature = "alsa_backend")] {
         let local_audio_device = config.audio_device.clone();
         let local_control_device = config.control_device.clone();
         let local_mixer = config.mixer.clone();
@@ -54,15 +60,12 @@ pub(crate) fn initial_state(
                         linear_scaling: linear,
                     }) as Box<dyn mixer::Mixer>
                 }) as Box<dyn FnMut() -> Box<dyn Mixer>>
-            }
         }
-    };
-
-    #[cfg(not(feature = "alsa_backend"))]
-    let mut mixer = {
-        info!("Using software volume controller.");
-        Box::new(|| Box::new(mixer::softmixer::SoftMixer::open(None)) as Box<dyn Mixer>)
+        }} else {
+            info!("Using software volume controller.");
+        mixer = Box::new(|| Box::new(mixer::softmixer::SoftMixer::open(None)) as Box<dyn Mixer>)
             as Box<dyn FnMut() -> Box<dyn Mixer>>
+        }
     };
 
     let cache = config.cache;
@@ -138,10 +141,17 @@ pub(crate) fn initial_state(
     let backend = find_backend(backend.as_ref().map(String::as_ref));
     main_loop::MainLoopState {
         librespot_connection: main_loop::LibreSpotConnection::new(connection, discovery_stream),
+        #[cfg(feature = "alsa_backend")]
+        audio_setup: main_loop::AudioSetup {
+            mixer,
+            backend,
+            audio_device: config.audio_device,
+        },
+        #[cfg(not(feature = "alsa_backend"))]
         audio_setup: main_loop::AudioSetup {
             mixer,
             backend,
-            audio_device: config.audio_device.clone(),
+            audio_device: None,
         },
         spotifyd_state: main_loop::SpotifydState {
             ctrl_c_stream: Box::new(ctrl_c(&handle).flatten_stream()),