music: add rescan option

Add an option to "rescan" the music library (i.e load without the cache).

If there are issues with the cache, this can be used instead.

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

@@ -44,8 +44,15 @@ class MusicViewModel : ViewModel(), Indexer.Callback {
         indexer.registerCallback(this)
     }
 
+    /**
+     * Re-index the music library.
+     */
     fun reindex() {
-        indexer.requestReindex()
+        indexer.requestReindex(true)
+    }
+
+    fun rescan() {
+        indexer.requestReindex(false)
     }
 
     override fun onIndexerStateChanged(state: Indexer.State?) {

app/src/main/java/org/oxycblt/auxio/music/extractor/CacheExtractor.kt

@@ -38,11 +38,15 @@ import java.io.File
  * modification times for files, as these are required for the cache to function well.
  * @author OxygenCobalt
  */
-class CacheExtractor(private val context: Context) {
+class CacheExtractor(private val context: Context, private val noop: Boolean) {
     private var cacheMap: Map<Long, Song.Raw>? = null
-    private var shouldWriteCache = false
+    private var shouldWriteCache = noop
 
     fun init() {
+        if (noop) {
+            return
+        }
+
         try {
             cacheMap = CacheDatabase.getInstance(context).read()
         } catch (e: Exception) {

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

@@ -24,7 +24,6 @@ import android.os.Build
 import androidx.core.content.ContextCompat
 import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.delay
 import kotlinx.coroutines.withContext
 import kotlinx.coroutines.yield
 import org.oxycblt.auxio.BuildConfig
@@ -134,8 +133,9 @@ class Indexer {
     /**
      * Start the indexing process. This should be done by [Controller] in a background thread. When
      * complete, a new completion state will be pushed to each callback.
+     * @param fresh Whether to use the cache when loading.
      */
-    suspend fun index(context: Context) {
+    suspend fun index(context: Context, fresh: Boolean) {
         val notGranted =
             ContextCompat.checkSelfPermission(context, PERMISSION_READ_AUDIO) ==
                 PackageManager.PERMISSION_DENIED
@@ -148,7 +148,7 @@ class Indexer {
         val response =
             try {
                 val start = System.currentTimeMillis()
-                val library = indexImpl(context)
+                val library = indexImpl(context, fresh)
                 if (library != null) {
                     logD(
                         "Music indexing completed successfully in " +
@@ -175,11 +175,12 @@ class Indexer {
     /**
      * Request that re-indexing should be done. This should be used by components that do not manage
      * the indexing process to re-index music.
+     * @param withCache Whether to use the cache when loading music.
      */
     @Synchronized
-    fun requestReindex() {
+    fun requestReindex(withCache: Boolean) {
         logD("Requesting reindex")
-        controller?.onStartIndexing()
+        controller?.onStartIndexing(withCache)
     }
 
     /**
@@ -196,13 +197,13 @@ class Indexer {
     /**
      * Run the proper music loading process.
      */
-    private suspend fun indexImpl(context: Context): MusicStore.Library? {
+    private suspend fun indexImpl(context: Context, withCache: Boolean): MusicStore.Library? {
         // Create the chain of extractors. Each extractor builds on the previous and
         // enables version-specific features in order to create the best possible music
         // experience. This is technically dependency injection. Except it doesn't increase
         // your compile times by 3x. Isn't that nice.
 
-        val cacheDatabase = CacheExtractor(context)
+        val cacheDatabase = CacheExtractor(context, !withCache)
 
         val mediaStoreExtractor =
             when {
@@ -434,7 +435,7 @@ class Indexer {
     }
 
     interface Controller : Callback {
-        fun onStartIndexing()
+        fun onStartIndexing(withCache: Boolean)
     }
 
     companion object {

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

@@ -89,7 +89,7 @@ class IndexerService : Service(), Indexer.Controller, Settings.Callback {
         indexer.registerController(this)
         if (musicStore.library == null && indexer.isIndeterminate) {
             logD("No library present and no previous response, indexing music now")
-            onStartIndexing()
+            onStartIndexing(true)
         }
 
         logD("Service created.")
@@ -117,13 +117,13 @@ class IndexerService : Service(), Indexer.Controller, Settings.Callback {
 
     // --- CONTROLLER CALLBACKS ---
 
-    override fun onStartIndexing() {
+    override fun onStartIndexing(withCache: Boolean) {
         if (indexer.isIndexing) {
             currentIndexJob?.cancel()
             indexer.cancelLast()
         }
 
-        currentIndexJob = indexScope.launch { indexer.index(this@IndexerService) }
+        currentIndexJob = indexScope.launch { indexer.index(this@IndexerService, withCache) }
     }
 
     override fun onIndexerStateChanged(state: Indexer.State?) {
@@ -228,7 +228,7 @@ class IndexerService : Service(), Indexer.Controller, Settings.Callback {
             getString(R.string.set_key_exclude_non_music),
             getString(R.string.set_key_music_dirs),
             getString(R.string.set_key_music_dirs_include),
-            getString(R.string.set_key_separators) -> onStartIndexing()
+            getString(R.string.set_key_separators) -> onStartIndexing(true)
             getString(R.string.set_key_observing) -> {
                 if (!indexer.isIndexing) {
                     updateIdleSession()
@@ -263,7 +263,8 @@ class IndexerService : Service(), Indexer.Controller, Settings.Callback {
             // Check here if we should even start a reindex. This is much less bug-prone than
             // registering and de-registering this component as this setting changes.
             if (settings.shouldBeObserving) {
-                onStartIndexing()
+                onSt
+                artIndexing(true)
             }
         }
     }

app/src/main/java/org/oxycblt/auxio/settings/prefs/PreferenceFragment.kt

@@ -145,6 +145,9 @@ class PreferenceFragment : PreferenceFragmentCompat() {
             context.getString(R.string.set_key_reindex) -> {
                 musicModel.reindex()
             }
+            context.getString(R.string.set_key_rescan) -> {
+                musicModel.rescan()
+            }
             else -> return super.onPreferenceTreeClick(preference)
         }
 

app/src/main/res/values/settings.xml

@@ -6,6 +6,7 @@
     <string name="set_key_accent" translatable="false">auxio_accent2</string>
 
     <string name="set_key_reindex" translatable="false">auxio_reindex</string>
+    <string name="set_key_rescan" translatable="false">auxio_rescan</string>
     <string name="set_key_observing" translatable="false">auxio_observing</string>
     <string name="set_key_music_dirs" translatable="false">auxio_music_dirs</string>
     <string name="set_key_cover_mode" translatable="false">auxio_cover_mode</string>

app/src/main/res/values/strings.xml

@@ -218,9 +218,12 @@
 
     <string name="set_content">Content</string>
     <string name="set_reindex">Reload music</string>
-    <string name="set_reindex_desc">May wipe playback state</string>
+    <string name="set_reindex_desc">Reload the music library, using the cache whenever possible</string>
+    <!-- Different from "Reload music" -->
+    <string name="set_rescan">Rescan music</string>
+    <string name="set_rescan_desc">Reload the music library and re-create the cache (Slower, but more complete)</string>
     <string name="set_observing">Automatic reloading</string>
-    <string name="set_observing_desc">Reload your music library whenever it changes (Requires persistent notification)</string>
+    <string name="set_observing_desc">Reload the music library whenever it changes (Requires persistent notification)</string>
     <string name="set_dirs">Music folders</string>
     <string name="set_dirs_desc">Manage where music should be loaded from</string>
     <!-- As in the mode to be used with the music folders setting -->

app/src/main/res/xml/prefs_main.xml

@@ -139,6 +139,10 @@
             app:key="@string/set_key_reindex"
             app:summary="@string/set_reindex_desc"
             app:title="@string/set_reindex" />
+        <Preference
+            app:key="@string/set_key_rescan"
+            app:summary="@string/set_rescan_desc"
+            app:title="@string/set_rescan" />
 
         <SwitchPreferenceCompat
             app:defaultValue="false"