music: cleanup old cover revisions

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

@@ -25,6 +25,7 @@ import javax.inject.Inject
 import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
+import kotlinx.coroutines.selects.select
 import kotlinx.coroutines.withContext
 import kotlinx.coroutines.yield
 import org.oxycblt.auxio.music.MusicRepository.IndexingWorker
@@ -361,25 +362,18 @@ constructor(
             }
         val locations = musicSettings.musicLocations
 
-        val revision: UUID
-        val storage: Storage
-        if (withCache) {
-            revision = musicSettings.revision
-            storage =
-                Storage(cache, MutableRevisionedStoredCovers(context, revision), storedPlaylists)
-        } else {
-            revision = UUID.randomUUID()
-            storage =
-                Storage(
-                    WriteOnlyCache(cache),
-                    MutableRevisionedStoredCovers(context, revision),
-                    storedPlaylists)
-        }
-
+        val currentRevision = musicSettings.revision
+        val newRevision = currentRevision?.takeIf { withCache } ?: UUID.randomUUID()
+        val cache = if (withCache) cache else WriteOnlyCache(cache)
+        val covers = MutableRevisionedStoredCovers(context, newRevision)
+        val storage = Storage(cache, covers, storedPlaylists)
         val interpretation = Interpretation(nameFactory, separators)
 
         val newLibrary =
             Musikr.new(context, storage, interpretation).run(locations, ::emitIndexingProgress)
+        // Music loading completed, update the revision right now so we re-use this work
+        // later.
+        musicSettings.revision = newRevision
 
         emitIndexingCompletion(null)
 
@@ -415,8 +409,9 @@ constructor(
             dispatchLibraryChange(deviceLibraryChanged, userLibraryChanged)
         }
 
-        // Quietly update the revision if needed (this way we don't disrupt any new loads)
-        musicSettings.revision = revision
+        // Old cover revisions may be lying around, even during a normal refresh due
+        // to realyl lucky cancellations. Clean those up.
+        RevisionedStoredCovers.cleanup(context, newRevision)
     }
 
     private suspend fun emitIndexingProgress(progress: IndexingProgress) {

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

@@ -35,7 +35,7 @@ import timber.log.Timber as L
  */
 interface MusicSettings : Settings<MusicSettings.Listener> {
     /** The current library revision. */
-    var revision: UUID
+    var revision: UUID?
     /** The locations of music to load. */
     var musicLocations: List<MusicLocation>
     /** Whether to exclude non-music audio files from the music library. */
@@ -58,11 +58,9 @@ interface MusicSettings : Settings<MusicSettings.Listener> {
 class MusicSettingsImpl @Inject constructor(@ApplicationContext private val context: Context) :
     Settings.Impl<MusicSettings.Listener>(context), MusicSettings {
 
-    override var revision: UUID
+    override var revision: UUID?
         get() =
-            UUID.fromString(
-                sharedPreferences.getString(getString(R.string.set_key_library_revision), null)
-                    ?: UUID.randomUUID().toString())
+            sharedPreferences.getString(getString(R.string.set_key_library_revision), null)?.let(UUID::fromString)
         set(value) {
             sharedPreferences.edit {
                 putString(getString(R.string.set_key_library_revision), value.toString())

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

@@ -15,16 +15,19 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
- 
+
 package org.oxycblt.auxio.music
 
 import android.content.Context
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
 import java.util.UUID
 import org.oxycblt.auxio.util.unlikelyToBeNull
 import org.oxycblt.musikr.cover.Cover
 import org.oxycblt.musikr.cover.CoverFormat
 import org.oxycblt.musikr.cover.MutableStoredCovers
 import org.oxycblt.musikr.cover.StoredCovers
+import java.io.File
 
 open class RevisionedStoredCovers(private val context: Context, private val revision: UUID?) :
     StoredCovers {
@@ -48,6 +51,13 @@ open class RevisionedStoredCovers(private val context: Context, private val revi
             return storedCovers.obtain(coverId)?.let { RevisionedCover(coverRevision, it) }
         }
     }
+
+    companion object {
+        suspend fun cleanup(context: Context, exclude: UUID) = withContext(Dispatchers.IO) {
+            context.filesDir.listFiles { file -> file.name.startsWith("covers_") && file.name != "covers_$exclude" }
+                ?.forEach { it.deleteRecursively() }
+        }
+    }
 }
 
 class MutableRevisionedStoredCovers(context: Context, private val revision: UUID) :