musikr: refactor devicefiles into tree

app/src/main/java/org/oxycblt/auxio/image/covers/CompatCovers.kt

@@ -30,7 +30,7 @@ import org.oxycblt.musikr.cover.CoverResult
 import org.oxycblt.musikr.cover.Covers
 import org.oxycblt.musikr.cover.FileCover
 import org.oxycblt.musikr.cover.MutableCovers
-import org.oxycblt.musikr.fs.DeviceFile
+import org.oxycblt.musikr.fs.device.DeviceFile
 import org.oxycblt.musikr.metadata.Metadata
 
 open class CompatCovers(private val context: Context, private val inner: Covers<FileCover>) :

app/src/main/java/org/oxycblt/auxio/image/covers/NullCovers.kt

@@ -22,7 +22,7 @@ import android.content.Context
 import org.oxycblt.musikr.cover.Cover
 import org.oxycblt.musikr.cover.CoverResult
 import org.oxycblt.musikr.cover.MutableCovers
-import org.oxycblt.musikr.fs.DeviceFile
+import org.oxycblt.musikr.fs.device.DeviceFile
 import org.oxycblt.musikr.metadata.Metadata
 
 class NullCovers(private val context: Context) : MutableCovers<NullCover> {

app/src/main/java/org/oxycblt/auxio/image/covers/SiloedCovers.kt

@@ -31,7 +31,7 @@ import org.oxycblt.musikr.cover.FileCover
 import org.oxycblt.musikr.cover.FileCovers
 import org.oxycblt.musikr.cover.MutableCovers
 import org.oxycblt.musikr.cover.MutableFileCovers
-import org.oxycblt.musikr.fs.DeviceFile
+import org.oxycblt.musikr.fs.device.DeviceFile
 import org.oxycblt.musikr.fs.app.AppFiles
 import org.oxycblt.musikr.metadata.Metadata
 

musikr/src/main/java/org/oxycblt/musikr/cache/Cache.kt

@@ -20,7 +20,7 @@ package org.oxycblt.musikr.cache
 
 import org.oxycblt.musikr.cover.Cover
 import org.oxycblt.musikr.cover.Covers
-import org.oxycblt.musikr.fs.DeviceFile
+import org.oxycblt.musikr.fs.device.DeviceFile
 import org.oxycblt.musikr.pipeline.RawSong
 
 abstract class Cache {

musikr/src/main/java/org/oxycblt/musikr/cache/CacheDatabase.kt

@@ -34,7 +34,7 @@ import androidx.room.TypeConverters
 import org.oxycblt.musikr.cover.Cover
 import org.oxycblt.musikr.cover.CoverResult
 import org.oxycblt.musikr.cover.Covers
-import org.oxycblt.musikr.fs.DeviceFile
+import org.oxycblt.musikr.fs.device.DeviceFile
 import org.oxycblt.musikr.metadata.Properties
 import org.oxycblt.musikr.pipeline.RawSong
 import org.oxycblt.musikr.tag.Date

musikr/src/main/java/org/oxycblt/musikr/cache/StoredCache.kt

@@ -21,7 +21,7 @@ package org.oxycblt.musikr.cache
 import android.content.Context
 import org.oxycblt.musikr.cover.Cover
 import org.oxycblt.musikr.cover.Covers
-import org.oxycblt.musikr.fs.DeviceFile
+import org.oxycblt.musikr.fs.device.DeviceFile
 import org.oxycblt.musikr.pipeline.RawSong
 
 interface StoredCache {

musikr/src/main/java/org/oxycblt/musikr/cover/Covers.kt

@@ -19,7 +19,7 @@
 package org.oxycblt.musikr.cover
 
 import java.io.InputStream
-import org.oxycblt.musikr.fs.DeviceFile
+import org.oxycblt.musikr.fs.device.DeviceFile
 import org.oxycblt.musikr.metadata.Metadata
 
 interface Covers<T : Cover> {

musikr/src/main/java/org/oxycblt/musikr/cover/FileCovers.kt

@@ -19,7 +19,7 @@
 package org.oxycblt.musikr.cover
 
 import android.os.ParcelFileDescriptor
-import org.oxycblt.musikr.fs.DeviceFile
+import org.oxycblt.musikr.fs.device.DeviceFile
 import org.oxycblt.musikr.fs.app.AppFile
 import org.oxycblt.musikr.fs.app.AppFiles
 import org.oxycblt.musikr.metadata.Metadata

musikr/src/main/java/org/oxycblt/musikr/fs/device/DeviceFile.kt

@@ -16,14 +16,29 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
  
-package org.oxycblt.musikr.fs
+package org.oxycblt.musikr.fs.device
 
 import android.net.Uri
+import kotlinx.coroutines.flow.Flow
+import org.oxycblt.musikr.fs.Path
+
+sealed interface DeviceNode {
+    val uri: Uri
+    val path: Path
+}
+
+data class DeviceDirectory(
+    override val uri: Uri,
+    override val path: Path,
+    val parent: DeviceDirectory?,
+    var children: Flow<DeviceNode>
+) : DeviceNode
 
 data class DeviceFile(
-    val uri: Uri,
+    override val uri: Uri,
+    override val path: Path,
+    val modifiedMs: Long,
     val mimeType: String,
-    val path: Path,
     val size: Long,
-    val modifiedMs: Long
+    val parent: DeviceDirectory
-)
+) : DeviceNode

musikr/src/main/java/org/oxycblt/musikr/fs/device/DeviceFiles.kt

@@ -24,17 +24,14 @@ import android.net.Uri
 import android.provider.DocumentsContract
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.Flow
-import kotlinx.coroutines.flow.asFlow
+import kotlinx.coroutines.flow.emptyFlow
-import kotlinx.coroutines.flow.emitAll
-import kotlinx.coroutines.flow.flatMapMerge
-import kotlinx.coroutines.flow.flattenMerge
 import kotlinx.coroutines.flow.flow
-import org.oxycblt.musikr.fs.DeviceFile
+import kotlinx.coroutines.flow.flatMapMerge
 import org.oxycblt.musikr.fs.MusicLocation
 import org.oxycblt.musikr.fs.Path
 
 internal interface DeviceFiles {
-    fun explore(locations: Flow<MusicLocation>, ignoreHidden: Boolean = true): Flow<DeviceFile>
+    fun explore(locations: Flow<MusicLocation>, ignoreHidden: Boolean = true): Flow<DeviceNode>
 
     companion object {
         fun from(context: Context): DeviceFiles = DeviceFilesImpl(context.contentResolverSafe)
@@ -43,23 +40,38 @@ internal interface DeviceFiles {
 
 @OptIn(ExperimentalCoroutinesApi::class)
 private class DeviceFilesImpl(private val contentResolver: ContentResolver) : DeviceFiles {
-    override fun explore(locations: Flow<MusicLocation>, ignoreHidden: Boolean): Flow<DeviceFile> =
+    override fun explore(locations: Flow<MusicLocation>, ignoreHidden: Boolean): Flow<DeviceNode> =
         locations.flatMapMerge { location ->
-            exploreImpl(
+            // Create a root directory for each location
+            val rootDirectory = DeviceDirectory(
+                uri = location.uri,
+                path = location.path,
+                parent = null,
+                children = emptyFlow()
+            )
+            
+            // Set up the children flow for the root directory
+            rootDirectory.children = exploreDirectoryImpl(
                 contentResolver,
                 location.uri,
                 DocumentsContract.getTreeDocumentId(location.uri),
                 location.path,
-                ignoreHidden)
+                rootDirectory,
+                ignoreHidden
+            )
+            
+            // Return a flow that emits the root directory
+            flow { emit(rootDirectory) }
         }
 
-    private fun exploreImpl(
+    private fun exploreDirectoryImpl(
         contentResolver: ContentResolver,
         rootUri: Uri,
         treeDocumentId: String,
         relativePath: Path,
+        parent: DeviceDirectory,
         ignoreHidden: Boolean
-    ): Flow<DeviceFile> = flow {
+    ): Flow<DeviceNode> = flow {
         contentResolver.useQuery(
             DocumentsContract.buildChildDocumentsUriUsingTree(rootUri, treeDocumentId),
             PROJECTION) { cursor ->
@@ -72,7 +84,7 @@ private class DeviceFilesImpl(private val contentResolver: ContentResolver) : De
                 val sizeIndex = cursor.getColumnIndexOrThrow(DocumentsContract.Document.COLUMN_SIZE)
                 val lastModifiedIndex =
                     cursor.getColumnIndexOrThrow(DocumentsContract.Document.COLUMN_LAST_MODIFIED)
-                val recursive = mutableListOf<Flow<DeviceFile>>()
+                
                 while (cursor.moveToNext()) {
                     val childId = cursor.getString(childUriIndex)
                     val displayName = cursor.getString(displayNameIndex)
@@ -84,27 +96,44 @@ private class DeviceFilesImpl(private val contentResolver: ContentResolver) : De
 
                     val newPath = relativePath.file(displayName)
                     val mimeType = cursor.getString(mimeTypeIndex)
+                    val lastModified = cursor.getLong(lastModifiedIndex)
+                    val childUri = DocumentsContract.buildDocumentUriUsingTree(rootUri, childId)
+                    
                     if (mimeType == DocumentsContract.Document.MIME_TYPE_DIR) {
-                        // This does NOT block the current coroutine. Instead, we will
+                        // Create a directory node with empty children flow initially
-                        // evaluate this flow in parallel later to maximize throughput.
+                        val directory = DeviceDirectory(
-                        recursive.add(
+                            uri = childUri,
-                            exploreImpl(contentResolver, rootUri, childId, newPath, ignoreHidden))
+                            path = newPath,
-                    } else if (mimeType.startsWith("audio/") && mimeType != "audio/x-mpegurl") {
+                            parent = parent,
-                        // Immediately emit all files given that it's just an O(1) op.
+                            children = emptyFlow()
-                        // This also just makes sure the outer flow has a reason to exist
+                        )
-                        // rather than just being a glorified async.
+                        
-                        val lastModified = cursor.getLong(lastModifiedIndex)
+                        // Set up the children flow for this directory
+                        directory.children = exploreDirectoryImpl(
+                            contentResolver,
+                            rootUri,
+                            childId,
+                            newPath,
+                            directory,
+                            ignoreHidden
+                        )
+                        
+                        // Emit the directory node
+                        emit(directory)
+                    } else {
                         val size = cursor.getLong(sizeIndex)
                         emit(
                             DeviceFile(
-                                DocumentsContract.buildDocumentUriUsingTree(rootUri, childId),
+                                uri = childUri,
-                                mimeType,
+                                mimeType = mimeType,
-                                newPath,
+                                path = newPath,
-                                size,
+                                size = size,
-                                lastModified))
+                                modifiedMs = lastModified,
+                                parent = parent
+                            )
+                        )
                     }
                 }
-                emitAll(recursive.asFlow().flattenMerge())
             }
     }
 

musikr/src/main/java/org/oxycblt/musikr/metadata/MetadataExtractor.kt

@@ -22,7 +22,7 @@ import android.os.ParcelFileDescriptor
 import java.io.FileInputStream
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
-import org.oxycblt.musikr.fs.DeviceFile
+import org.oxycblt.musikr.fs.device.DeviceFile
 
 internal interface MetadataExtractor {
     suspend fun extract(deviceFile: DeviceFile, fd: ParcelFileDescriptor): Metadata?

musikr/src/main/java/org/oxycblt/musikr/metadata/NativeInputStream.kt

@@ -21,7 +21,7 @@ package org.oxycblt.musikr.metadata
 import android.util.Log
 import java.io.FileInputStream
 import java.nio.ByteBuffer
-import org.oxycblt.musikr.fs.DeviceFile
+import org.oxycblt.musikr.fs.device.DeviceFile
 
 internal class NativeInputStream(private val deviceFile: DeviceFile, fis: FileInputStream) {
     private val channel = fis.channel

musikr/src/main/java/org/oxycblt/musikr/metadata/TagLibJNI.kt

@@ -19,7 +19,7 @@
 package org.oxycblt.musikr.metadata
 
 import java.io.FileInputStream
-import org.oxycblt.musikr.fs.DeviceFile
+import org.oxycblt.musikr.fs.device.DeviceFile
 
 internal object TagLibJNI {
     init {

musikr/src/main/java/org/oxycblt/musikr/pipeline/ExploreStep.kt

@@ -20,17 +20,20 @@ package org.oxycblt.musikr.pipeline
 
 import android.content.Context
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.asFlow
 import kotlinx.coroutines.flow.buffer
 import kotlinx.coroutines.flow.emitAll
+import kotlinx.coroutines.flow.flattenMerge
 import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.flow.flowOn
 import kotlinx.coroutines.flow.map
-import kotlinx.coroutines.flow.mapNotNull
 import kotlinx.coroutines.flow.merge
 import org.oxycblt.musikr.Storage
-import org.oxycblt.musikr.fs.DeviceFile
+import org.oxycblt.musikr.fs.device.DeviceDirectory
+import org.oxycblt.musikr.fs.device.DeviceFile
+import org.oxycblt.musikr.fs.device.DeviceNode
 import org.oxycblt.musikr.fs.MusicLocation
 import org.oxycblt.musikr.fs.device.DeviceFiles
 import org.oxycblt.musikr.playlist.PlaylistFile
@@ -54,12 +57,8 @@ private class ExploreStepImpl(
         val audios =
             deviceFiles
                 .explore(locations.asFlow())
-                .mapNotNull {
+                .flattenFilter {
-                    when {
+                    it.mimeType.startsWith("audio/") || it.mimeType == M3U.MIME_TYPE
-                        it.mimeType == M3U.MIME_TYPE -> null
-                        it.mimeType.startsWith("audio/") -> ExploreNode.Audio(it)
-                        else -> null
-                    }
                 }
                 .flowOn(Dispatchers.IO)
                 .buffer()
@@ -70,6 +69,19 @@ private class ExploreStepImpl(
                 .buffer()
         return merge(audios, playlists)
     }
+
+    @OptIn(ExperimentalCoroutinesApi::class)
+    private fun Flow<DeviceNode>.flattenFilter(block: (DeviceFile) -> Boolean): Flow<ExploreNode> = flow {
+        collect {
+            val recurse = mutableListOf<Flow<ExploreNode>>()
+            when {
+                it is DeviceFile && block(it) -> emit(ExploreNode.Audio(it))
+                it is DeviceDirectory -> recurse.add(it.children.flattenFilter(block))
+                else -> {}
+            }
+            emitAll(recurse.asFlow().flattenMerge())
+        }
+    }
 }
 
 internal sealed interface ExploreNode {

musikr/src/main/java/org/oxycblt/musikr/pipeline/ExtractStep.kt

@@ -37,7 +37,7 @@ import org.oxycblt.musikr.cache.CacheResult
 import org.oxycblt.musikr.cover.Cover
 import org.oxycblt.musikr.cover.CoverResult
 import org.oxycblt.musikr.cover.MutableCovers
-import org.oxycblt.musikr.fs.DeviceFile
+import org.oxycblt.musikr.fs.device.DeviceFile
 import org.oxycblt.musikr.metadata.MetadataExtractor
 import org.oxycblt.musikr.metadata.Properties
 import org.oxycblt.musikr.playlist.PlaylistFile

musikr/src/main/java/org/oxycblt/musikr/pipeline/PipelineException.kt

@@ -18,7 +18,7 @@
  
 package org.oxycblt.musikr.pipeline
 
-import org.oxycblt.musikr.fs.DeviceFile
+import org.oxycblt.musikr.fs.device.DeviceFile
 import org.oxycblt.musikr.playlist.PlaylistFile
 import org.oxycblt.musikr.playlist.interpret.PrePlaylist
 import org.oxycblt.musikr.tag.interpret.PreSong

musikr/src/main/java/org/oxycblt/musikr/tag/interpret/TagInterpreter.kt

@@ -20,7 +20,7 @@ package org.oxycblt.musikr.tag.interpret
 
 import org.oxycblt.musikr.Interpretation
 import org.oxycblt.musikr.Music
-import org.oxycblt.musikr.fs.DeviceFile
+import org.oxycblt.musikr.fs.device.DeviceFile
 import org.oxycblt.musikr.fs.Format
 import org.oxycblt.musikr.pipeline.RawSong
 import org.oxycblt.musikr.tag.Disc