music: hide musicstore impl

Hide the MusicStore implementation behind an interface, transforming it
into a new MusicRepository class.

This is in preparation for dependency injection.

app/src/main/java/org/oxycblt/auxio/detail/DetailViewModel.kt

@@ -32,7 +32,6 @@ import org.oxycblt.auxio.detail.recycler.SortHeader
 import org.oxycblt.auxio.list.BasicHeader
 import org.oxycblt.auxio.list.Item
 import org.oxycblt.auxio.music.*
-import org.oxycblt.auxio.music.MusicStore
 import org.oxycblt.auxio.music.format.AudioInfo
 import org.oxycblt.auxio.music.format.Disc
 import org.oxycblt.auxio.music.format.ReleaseType
@@ -49,8 +48,8 @@ import org.oxycblt.auxio.util.*
  * @author Alexander Capehart (OxygenCobalt)
  */
 class DetailViewModel(application: Application) :
-    AndroidViewModel(application), MusicStore.Listener {
+    AndroidViewModel(application), MusicRepository.Listener {
-    private val musicStore = MusicStore.getInstance()
+    private val musicRepository = MusicRepository.get()
     private val musicSettings = MusicSettings.from(application)
     private val playbackSettings = PlaybackSettings.from(application)
     private val audioInfoProvider = AudioInfo.Provider.from(application)
@@ -137,11 +136,11 @@ class DetailViewModel(application: Application) :
         get() = playbackSettings.inParentPlaybackMode
 
     init {
-        musicStore.addListener(this)
+        musicRepository.addListener(this)
     }
 
     override fun onCleared() {
-        musicStore.removeListener(this)
+        musicRepository.removeListener(this)
     }
 
     override fun onLibraryChanged(library: Library?) {
@@ -235,7 +234,7 @@ class DetailViewModel(application: Application) :
         _currentGenre.value = requireMusic<Genre>(uid)?.also(::refreshGenreList)
     }
 
-    private fun <T : Music> requireMusic(uid: Music.UID) = musicStore.library?.find<T>(uid)
+    private fun <T : Music> requireMusic(uid: Music.UID) = musicRepository.library?.find<T>(uid)
 
     /**
      * Start a new job to load a given [Song]'s [AudioInfo]. Result is pushed to [songAudioInfo].

app/src/main/java/org/oxycblt/auxio/home/HomeViewModel.kt

@@ -23,7 +23,6 @@ import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import org.oxycblt.auxio.home.tabs.Tab
 import org.oxycblt.auxio.music.*
-import org.oxycblt.auxio.music.MusicStore
 import org.oxycblt.auxio.music.library.Library
 import org.oxycblt.auxio.music.library.Sort
 import org.oxycblt.auxio.playback.PlaybackSettings
@@ -34,8 +33,8 @@ import org.oxycblt.auxio.util.logD
  * @author Alexander Capehart (OxygenCobalt)
  */
 class HomeViewModel(application: Application) :
-    AndroidViewModel(application), MusicStore.Listener, HomeSettings.Listener {
+    AndroidViewModel(application), MusicRepository.Listener, HomeSettings.Listener {
-    private val musicStore = MusicStore.getInstance()
+    private val musicRepository = MusicRepository.get()
     private val homeSettings = HomeSettings.from(application)
     private val musicSettings = MusicSettings.from(application)
     private val playbackSettings = PlaybackSettings.from(application)
@@ -92,13 +91,13 @@ class HomeViewModel(application: Application) :
     val isFastScrolling: StateFlow<Boolean> = _isFastScrolling
 
     init {
-        musicStore.addListener(this)
+        musicRepository.addListener(this)
         homeSettings.registerListener(this)
     }
 
     override fun onCleared() {
         super.onCleared()
-        musicStore.removeListener(this)
+        musicRepository.removeListener(this)
         homeSettings.unregisterListener(this)
     }
 
@@ -130,7 +129,7 @@ class HomeViewModel(application: Application) :
     override fun onHideCollaboratorsChanged() {
         // Changes in the hide collaborator setting will change the artist contents
         // of the library, consider it a library update.
-        onLibraryChanged(musicStore.library)
+        onLibraryChanged(musicRepository.library)
     }
 
     /**

app/src/main/java/org/oxycblt/auxio/list/selection/SelectionViewModel.kt

@@ -21,15 +21,14 @@ import androidx.lifecycle.ViewModel
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import org.oxycblt.auxio.music.*
-import org.oxycblt.auxio.music.MusicStore
 import org.oxycblt.auxio.music.library.Library
 
 /**
  * A [ViewModel] that manages the current selection.
  * @author Alexander Capehart (OxygenCobalt)
  */
-class SelectionViewModel : ViewModel(), MusicStore.Listener {
+class SelectionViewModel : ViewModel(), MusicRepository.Listener {
-    private val musicStore = MusicStore.getInstance()
+    private val musicRepository = MusicRepository.get()
 
     private val _selected = MutableStateFlow(listOf<Music>())
     /** the currently selected items. These are ordered in earliest selected and latest selected. */
@@ -37,7 +36,7 @@ class SelectionViewModel : ViewModel(), MusicStore.Listener {
         get() = _selected
 
     init {
-        musicStore.addListener(this)
+        musicRepository.addListener(this)
     }
 
     override fun onLibraryChanged(library: Library?) {
@@ -60,7 +59,7 @@ class SelectionViewModel : ViewModel(), MusicStore.Listener {
 
     override fun onCleared() {
         super.onCleared()
-        musicStore.removeListener(this)
+        musicRepository.removeListener(this)
     }
 
     /**

app/src/main/java/org/oxycblt/auxio/music/MusicRepository.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021 Auxio Project
+ * Copyright (c) 2023 Auxio Project
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -28,22 +28,13 @@ import org.oxycblt.auxio.music.library.Library
  *
  * @author Alexander Capehart (OxygenCobalt)
  */
-class MusicStore private constructor() {
+interface MusicRepository {
-    private val listeners = mutableListOf<Listener>()
-
     /**
      * The current [Library]. May be null if a [Library] has not been successfully loaded yet. This
      * can change, so it's highly recommended to not access this directly and instead rely on
      * [Listener].
      */
-    @Volatile
+    var library: Library?
-    var library: Library? = null
-        set(value) {
-            field = value
-            for (callback in listeners) {
-                callback.onLibraryChanged(library)
-            }
-        }
 
     /**
      * Add a [Listener] to this instance. This can be used to receive changes in the music library.
@@ -51,11 +42,7 @@ class MusicStore private constructor() {
      * @param listener The [Listener] to add.
      * @see Listener
      */
-    @Synchronized
+    fun addListener(listener: Listener)
-    fun addListener(listener: Listener) {
-        listener.onLibraryChanged(library)
-        listeners.add(listener)
-    }
 
     /**
      * Remove a [Listener] from this instance, preventing it from receiving any further updates.
@@ -63,12 +50,9 @@ class MusicStore private constructor() {
      * the first place.
      * @see Listener
      */
-    @Synchronized
+    fun removeListener(listener: Listener)
-    fun removeListener(listener: Listener) {
-        listeners.remove(listener)
-    }
 
-    /** A listener for changes in the music library. */
+    /** A listener for changes in [MusicRepository] */
     interface Listener {
         /**
          * Called when the current [Library] has changed.
@@ -78,23 +62,47 @@ class MusicStore private constructor() {
     }
 
     companion object {
-        @Volatile private var INSTANCE: MusicStore? = null
+        @Volatile private var INSTANCE: MusicRepository? = null
 
         /**
          * Get a singleton instance.
          * @return The (possibly newly-created) singleton instance.
          */
-        fun getInstance(): MusicStore {
+        fun get(): MusicRepository {
             val currentInstance = INSTANCE
             if (currentInstance != null) {
                 return currentInstance
             }
 
             synchronized(this) {
-                val newInstance = MusicStore()
+                val newInstance = RealMusicRepository()
                 INSTANCE = newInstance
                 return newInstance
             }
         }
     }
 }
+
+private class RealMusicRepository : MusicRepository {
+    private val listeners = mutableListOf<MusicRepository.Listener>()
+
+    @Volatile
+    override var library: Library? = null
+        set(value) {
+            field = value
+            for (callback in listeners) {
+                callback.onLibraryChanged(library)
+            }
+        }
+
+    @Synchronized
+    override fun addListener(listener: MusicRepository.Listener) {
+        listener.onLibraryChanged(library)
+        listeners.add(listener)
+    }
+
+    @Synchronized
+    override fun removeListener(listener: MusicRepository.Listener) {
+        listeners.remove(listener)
+    }
+}

app/src/main/java/org/oxycblt/auxio/music/library/Library.kt

@@ -29,7 +29,8 @@ import org.oxycblt.auxio.util.logD
  * Organized music library information.
  *
  * This class allows for the creation of a well-formed music library graph from raw song
- * information. It's generally not expected to create this yourself and instead use [MusicStore].
+ * information. It's generally not expected to create this yourself and instead use
+ * [MusicRepository].
  *
  * @author Alexander Capehart
  */

app/src/main/java/org/oxycblt/auxio/music/picker/PickerViewModel.kt

@@ -21,7 +21,6 @@ import androidx.lifecycle.ViewModel
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import org.oxycblt.auxio.music.*
-import org.oxycblt.auxio.music.MusicStore
 import org.oxycblt.auxio.music.library.Library
 import org.oxycblt.auxio.util.unlikelyToBeNull
 
@@ -30,8 +29,8 @@ import org.oxycblt.auxio.util.unlikelyToBeNull
  * contain the music themselves and then exit if the library changes.
  * @author Alexander Capehart (OxygenCobalt)
  */
-class PickerViewModel : ViewModel(), MusicStore.Listener {
+class PickerViewModel : ViewModel(), MusicRepository.Listener {
-    private val musicStore = MusicStore.getInstance()
+    private val musicRepository = MusicRepository.get()
 
     private val _currentItem = MutableStateFlow<Music?>(null)
     /** The current item whose artists should be shown in the picker. Null if there is no item. */
@@ -49,7 +48,7 @@ class PickerViewModel : ViewModel(), MusicStore.Listener {
         get() = _genreChoices
 
     override fun onCleared() {
-        musicStore.removeListener(this)
+        musicRepository.removeListener(this)
     }
 
     override fun onLibraryChanged(library: Library?) {
@@ -63,7 +62,7 @@ class PickerViewModel : ViewModel(), MusicStore.Listener {
      * @param uid The [Music.UID] of the [Song] to update to.
      */
     fun setItemUid(uid: Music.UID) {
-        val library = unlikelyToBeNull(musicStore.library)
+        val library = unlikelyToBeNull(musicRepository.library)
         _currentItem.value = library.find(uid)
         refreshChoices()
     }

app/src/main/java/org/oxycblt/auxio/music/system/Indexer.kt

@@ -39,8 +39,8 @@ import org.oxycblt.auxio.util.logW
  *
  * This class provides low-level access into the exact state of the music loading process. **This
  * class should not be used in most cases.** It is highly volatile and provides far more information
- * than is usually needed. Use [MusicStore] instead if you do not need to work with the exact music
+ * than is usually needed. Use [MusicRepository] instead if you do not need to work with the exact
- * loading state.
+ * music loading state.
  *
  * @author Alexander Capehart (OxygenCobalt)
  */
@@ -345,8 +345,8 @@ class Indexer private constructor() {
      * A listener for rapid-fire changes in the music loading state.
      *
      * This is only useful for code that absolutely must show the current loading process.
-     * Otherwise, [MusicStore.Listener] is highly recommended due to it's updates only consisting of
+     * Otherwise, [MusicRepository.Listener] is highly recommended due to it's updates only
-     * the [Library].
+     * consisting of the [Library].
      */
     interface Listener {
         /**

app/src/main/java/org/oxycblt/auxio/music/system/IndexerService.kt

@@ -31,8 +31,8 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.launch
 import org.oxycblt.auxio.BuildConfig
+import org.oxycblt.auxio.music.MusicRepository
 import org.oxycblt.auxio.music.MusicSettings
-import org.oxycblt.auxio.music.MusicStore
 import org.oxycblt.auxio.music.storage.contentResolverSafe
 import org.oxycblt.auxio.playback.state.PlaybackStateManager
 import org.oxycblt.auxio.service.ForegroundManager
@@ -55,7 +55,7 @@ import org.oxycblt.auxio.util.logD
  */
 class IndexerService : Service(), Indexer.Controller, MusicSettings.Listener {
     private val indexer = Indexer.getInstance()
-    private val musicStore = MusicStore.getInstance()
+    private val musicRepository = MusicRepository.get()
     private val playbackManager = PlaybackStateManager.get()
     private val serviceJob = Job()
     private val indexScope = CoroutineScope(serviceJob + Dispatchers.IO)
@@ -85,7 +85,7 @@ class IndexerService : Service(), Indexer.Controller, MusicSettings.Listener {
         indexer.registerController(this)
         // An indeterminate indexer and a missing library implies we are extremely early
         // in app initialization so start loading music.
-        if (musicStore.library == null && indexer.isIndeterminate) {
+        if (musicRepository.library == null && indexer.isIndeterminate) {
             logD("No library present and no previous response, indexing music now")
             onStartIndexing(true)
         }
@@ -129,11 +129,11 @@ class IndexerService : Service(), Indexer.Controller, MusicSettings.Listener {
             is Indexer.State.Indexing -> updateActiveSession(state.indexing)
             is Indexer.State.Complete -> {
                 val newLibrary = state.result.getOrNull()
-                if (newLibrary != null && newLibrary != musicStore.library) {
+                if (newLibrary != null && newLibrary != musicRepository.library) {
                     logD("Applying new library")
                     // We only care if the newly-loaded library is going to replace a previously
                     // loaded library.
-                    if (musicStore.library != null) {
+                    if (musicRepository.library != null) {
                         // Wipe possibly-invalidated outdated covers
                         imageLoader.memoryCache?.clear()
                         // Clear invalid models from PlaybackStateManager. This is not connected
@@ -153,7 +153,7 @@ class IndexerService : Service(), Indexer.Controller, MusicSettings.Listener {
                         }
                     }
                     // Forward the new library to MusicStore to continue the update process.
-                    musicStore.library = newLibrary
+                    musicRepository.library = newLibrary
                 }
                 // On errors, while we would want to show a notification that displays the
                 // error, that requires the Android 13 notification permission, which is not

app/src/main/java/org/oxycblt/auxio/playback/PlaybackViewModel.kt

@@ -40,7 +40,7 @@ class PlaybackViewModel(application: Application) :
     private val playbackSettings = PlaybackSettings.from(application)
     private val playbackManager = PlaybackStateManager.get()
     private val persistenceRepository = PersistenceRepository.from(application)
-    private val musicStore = MusicStore.getInstance()
+    private val musicRepository = MusicRepository.get()
     private var lastPositionJob: Job? = null
 
     private val _song = MutableStateFlow<Song?>(null)
@@ -279,7 +279,7 @@ class PlaybackViewModel(application: Application) :
         check(song == null || parent == null || parent.songs.contains(song)) {
             "Song to play not in parent"
         }
-        val library = musicStore.library ?: return
+        val library = musicRepository.library ?: return
         val sort =
             when (parent) {
                 is Genre -> musicSettings.genreSongSort
@@ -449,7 +449,7 @@ class PlaybackViewModel(application: Application) :
      */
     fun tryRestorePlaybackState(onDone: (Boolean) -> Unit) {
         viewModelScope.launch {
-            val library = musicStore.library
+            val library = musicRepository.library
             if (library != null) {
                 val savedState = persistenceRepository.readState(library)
                 if (savedState != null) {

app/src/main/java/org/oxycblt/auxio/playback/system/PlaybackService.kt

@@ -43,8 +43,8 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.launch
 import org.oxycblt.auxio.BuildConfig
+import org.oxycblt.auxio.music.MusicRepository
 import org.oxycblt.auxio.music.MusicSettings
-import org.oxycblt.auxio.music.MusicStore
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.music.library.Library
 import org.oxycblt.auxio.playback.PlaybackSettings
@@ -80,7 +80,7 @@ class PlaybackService :
     Player.Listener,
     InternalPlayer,
     MediaSessionComponent.Listener,
-    MusicStore.Listener {
+    MusicRepository.Listener {
     // Player components
     private lateinit var player: ExoPlayer
     private lateinit var replayGainProcessor: ReplayGainAudioProcessor
@@ -90,12 +90,12 @@ class PlaybackService :
     private lateinit var widgetComponent: WidgetComponent
     private val systemReceiver = PlaybackReceiver()
 
-    // Managers
+    // Shared components
     private val playbackManager = PlaybackStateManager.get()
-    private val musicStore = MusicStore.getInstance()
-    private lateinit var musicSettings: MusicSettings
     private lateinit var playbackSettings: PlaybackSettings
     private lateinit var persistenceRepository: PersistenceRepository
+    private val musicRepository = MusicRepository.get()
+    private lateinit var musicSettings: MusicSettings
 
     // State
     private lateinit var foregroundManager: ForegroundManager
@@ -153,7 +153,7 @@ class PlaybackService :
         // Initialize any listener-dependent components last as we wouldn't want a listener race
         // condition to cause us to load music before we were fully initialize.
         playbackManager.registerInternalPlayer(this)
-        musicStore.addListener(this)
+        musicRepository.addListener(this)
         widgetComponent = WidgetComponent(this)
         mediaSessionComponent = MediaSessionComponent(this, this)
         registerReceiver(
@@ -193,7 +193,7 @@ class PlaybackService :
         // Pause just in case this destruction was unexpected.
         playbackManager.setPlaying(false)
         playbackManager.unregisterInternalPlayer(this)
-        musicStore.removeListener(this)
+        musicRepository.removeListener(this)
 
         unregisterReceiver(systemReceiver)
         serviceJob.cancel()
@@ -339,7 +339,7 @@ class PlaybackService :
 
     override fun performAction(action: InternalPlayer.Action): Boolean {
         val library =
-            musicStore.library
+            musicRepository.library
             // No library, cannot do anything.
             ?: return false
 

app/src/main/java/org/oxycblt/auxio/search/SearchViewModel.kt

@@ -30,7 +30,6 @@ import org.oxycblt.auxio.R
 import org.oxycblt.auxio.list.BasicHeader
 import org.oxycblt.auxio.list.Item
 import org.oxycblt.auxio.music.*
-import org.oxycblt.auxio.music.MusicStore
 import org.oxycblt.auxio.music.library.Library
 import org.oxycblt.auxio.music.library.Sort
 import org.oxycblt.auxio.playback.PlaybackSettings
@@ -41,8 +40,8 @@ import org.oxycblt.auxio.util.logD
  * @author Alexander Capehart (OxygenCobalt)
  */
 class SearchViewModel(application: Application) :
-    AndroidViewModel(application), MusicStore.Listener {
+    AndroidViewModel(application), MusicRepository.Listener {
-    private val musicStore = MusicStore.getInstance()
+    private val musicRepository = MusicRepository.get()
     private val searchSettings = SearchSettings.from(application)
     private val playbackSettings = PlaybackSettings.from(application)
     private var searchEngine = SearchEngine.from(application)
@@ -59,12 +58,12 @@ class SearchViewModel(application: Application) :
         get() = playbackSettings.inListPlaybackMode
 
     init {
-        musicStore.addListener(this)
+        musicRepository.addListener(this)
     }
 
     override fun onCleared() {
         super.onCleared()
-        musicStore.removeListener(this)
+        musicRepository.removeListener(this)
     }
 
     override fun onLibraryChanged(library: Library?) {
@@ -84,7 +83,7 @@ class SearchViewModel(application: Application) :
         currentSearchJob?.cancel()
         lastQuery = query
 
-        val library = musicStore.library
+        val library = musicRepository.library
         if (query.isNullOrEmpty() || library == null) {
             logD("Search query is not applicable.")
             _searchResults.value = listOf()