music: more m3u support

- Turns out path extraction via MediaStore doesn't work, have to grok
the URI format.
- Added playlist name extraction
- Proactively handling whitespace

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

@@ -24,8 +24,8 @@ import androidx.core.content.edit
 import dagger.hilt.android.qualifiers.ApplicationContext
 import javax.inject.Inject
 import org.oxycblt.auxio.R
-import org.oxycblt.auxio.music.dirs.DocumentTreePathFactory
 import org.oxycblt.auxio.music.dirs.MusicDirectories
+import org.oxycblt.auxio.music.fs.DocumentPathFactory
 import org.oxycblt.auxio.settings.Settings
 import org.oxycblt.auxio.util.getSystemServiceCompat
 import org.oxycblt.auxio.util.logD
@@ -57,10 +57,8 @@ interface MusicSettings : Settings<MusicSettings.Listener> {
 
 class MusicSettingsImpl
 @Inject
-constructor(
-    @ApplicationContext context: Context,
-    val documentTreePathFactory: DocumentTreePathFactory
-) : Settings.Impl<MusicSettings.Listener>(context), MusicSettings {
+constructor(@ApplicationContext context: Context, val documentPathFactory: DocumentPathFactory) :
+    Settings.Impl<MusicSettings.Listener>(context), MusicSettings {
     private val storageManager = context.getSystemServiceCompat(StorageManager::class)
 
     override var musicDirs: MusicDirectories
@@ -68,7 +66,7 @@ constructor(
             val dirs =
                 (sharedPreferences.getStringSet(getString(R.string.set_key_music_dirs), null)
                         ?: emptySet())
-                    .mapNotNull(documentTreePathFactory::deserializeDocumentTreePath)
+                    .mapNotNull(documentPathFactory::fromDocumentId)
             return MusicDirectories(
                 dirs,
                 sharedPreferences.getBoolean(getString(R.string.set_key_music_dirs_include), false))
@@ -77,7 +75,7 @@ constructor(
             sharedPreferences.edit {
                 putStringSet(
                     getString(R.string.set_key_music_dirs),
-                    value.dirs.map(documentTreePathFactory::serializeDocumentTreePath).toSet())
+                    value.dirs.map(documentPathFactory::toDocumentId).toSet())
                 putBoolean(getString(R.string.set_key_music_dirs_include), value.shouldInclude)
                 apply()
             }

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

@@ -141,6 +141,11 @@ constructor(
             val deviceLibrary = musicRepository.deviceLibrary ?: return@launch
             val songs = importedPlaylist.paths.mapNotNull(deviceLibrary::findSongByPath)
 
+            if (songs.isEmpty()) {
+                _importError.put(Unit)
+                return@launch
+            }
+
             createPlaylist(importedPlaylist.name, songs)
         }
 

app/src/main/java/org/oxycblt/auxio/music/dirs/DirectoryModule.kt

@@ -18,14 +18,8 @@
  
 package org.oxycblt.auxio.music.dirs
 
-import dagger.Binds
 import dagger.Module
 import dagger.hilt.InstallIn
 import dagger.hilt.components.SingletonComponent
 
-@Module
-@InstallIn(SingletonComponent::class)
-interface DirectoryModule {
-    @Binds
-    fun documentTreePathFactory(factory: DocumentTreePathFactoryImpl): DocumentTreePathFactory
-}
+@Module @InstallIn(SingletonComponent::class) interface DirectoryModule {}

app/src/main/java/org/oxycblt/auxio/music/dirs/MusicDirsDialog.kt

@@ -33,6 +33,7 @@ import org.oxycblt.auxio.BuildConfig
 import org.oxycblt.auxio.R
 import org.oxycblt.auxio.databinding.DialogMusicDirsBinding
 import org.oxycblt.auxio.music.MusicSettings
+import org.oxycblt.auxio.music.fs.DocumentPathFactory
 import org.oxycblt.auxio.music.fs.Path
 import org.oxycblt.auxio.ui.ViewBindingMaterialDialogFragment
 import org.oxycblt.auxio.util.logD
@@ -48,7 +49,7 @@ class MusicDirsDialog :
     ViewBindingMaterialDialogFragment<DialogMusicDirsBinding>(), DirectoryAdapter.Listener {
     private val dirAdapter = DirectoryAdapter(this)
     private var openDocumentTreeLauncher: ActivityResultLauncher<Uri?>? = null
-    @Inject lateinit var documentTreePathFactory: DocumentTreePathFactory
+    @Inject lateinit var documentPathFactory: DocumentPathFactory
     @Inject lateinit var musicSettings: MusicSettings
 
     override fun onCreateBinding(inflater: LayoutInflater) =
@@ -101,8 +102,7 @@ class MusicDirsDialog :
             if (pendingDirs != null) {
                 dirs =
                     MusicDirectories(
-                        pendingDirs.mapNotNull(
-                            documentTreePathFactory::deserializeDocumentTreePath),
+                        pendingDirs.mapNotNull(documentPathFactory::fromDocumentId),
                         savedInstanceState.getBoolean(KEY_PENDING_MODE))
             }
         }
@@ -126,8 +126,7 @@ class MusicDirsDialog :
     override fun onSaveInstanceState(outState: Bundle) {
         super.onSaveInstanceState(outState)
         outState.putStringArrayList(
-            KEY_PENDING_DIRS,
-            ArrayList(dirAdapter.dirs.map(documentTreePathFactory::serializeDocumentTreePath)))
+            KEY_PENDING_DIRS, ArrayList(dirAdapter.dirs.map(documentPathFactory::toDocumentId)))
         outState.putBoolean(KEY_PENDING_MODE, isUiModeInclude(requireBinding()))
     }
 
@@ -155,7 +154,7 @@ class MusicDirsDialog :
             return
         }
 
-        val dir = documentTreePathFactory.unpackDocumentTreeUri(uri)
+        val dir = documentPathFactory.unpackDocumentTreeUri(uri)
 
         if (dir != null) {
             dirAdapter.add(dir)

app/src/main/java/org/oxycblt/auxio/music/external/M3U.kt

@@ -24,39 +24,81 @@ import java.io.InputStreamReader
 import javax.inject.Inject
 import org.oxycblt.auxio.music.fs.Components
 import org.oxycblt.auxio.music.fs.Path
+import org.oxycblt.auxio.music.metadata.correctWhitespace
 import org.oxycblt.auxio.util.logW
 
+/**
+ * Minimal M3U file format implementation.
+ *
+ * @author Alexander Capehart (OxygenCobalt)
+ */
 interface M3U {
-    fun read(stream: InputStream, workingDirectory: Path): List<Path>?
+    /**
+     * Reads an M3U file from the given [stream] and returns a [ImportedPlaylist] containing the
+     * paths to the files listed in the M3U file.
+     *
+     * @param stream The stream to read the M3U file from.
+     * @param workingDirectory The directory that the M3U file is contained in. This is used to
+     *   resolve relative paths.
+     * @return An [ImportedPlaylist] containing the paths to the files listed in the M3U file,
+     */
+    fun read(stream: InputStream, workingDirectory: Path): ImportedPlaylist?
 }
 
 class M3UImpl @Inject constructor() : M3U {
-    override fun read(stream: InputStream, workingDirectory: Path): List<Path>? {
+    override fun read(stream: InputStream, workingDirectory: Path): ImportedPlaylist? {
         val reader = BufferedReader(InputStreamReader(stream))
-        val media = mutableListOf<Path>()
+        val paths = mutableListOf<Path>()
+        var name: String? = null
 
         consumeFile@ while (true) {
+            var path: String?
             collectMetadata@ while (true) {
-                val line = reader.readLine() ?: break@consumeFile
-                if (!line.startsWith("#")) {
+                // The M3U format consists of "entries" that begin with a bunch of metadata
+                // prefixed with "#", and then a relative/absolute path or url to the file.
+                // We don't really care about the metadata except for the playlist name, so
+                // we discard everything but that.
+                val currentLine =
+                    (reader.readLine() ?: break@consumeFile).correctWhitespace()
+                        ?: continue@collectMetadata
+                if (currentLine.startsWith("#")) {
+                    // Metadata entries are roughly structured
+                    val split = currentLine.split(":", limit = 2)
+                    when (split[0]) {
+                        // Playlist name
+                        "#PLAYLIST" -> name = split.getOrNull(1)?.correctWhitespace()
+                        // Add more metadata handling here if needed.
+                        else -> {}
+                    }
+                } else {
+                    // Something that isn't a metadata entry, assume it's a path. It could be
+                    // a URL, but it'll just get mangled really badly and not match with anything,
+                    // so it's okay.
+                    path = currentLine
                     break@collectMetadata
                 }
             }
 
-            val path = reader.readLine()
             if (path == null) {
                 logW("Expected a path, instead got an EOF")
                 break@consumeFile
             }
 
+            // The path may be relative to the directory that the M3U file is contained in,
+            // so we may need to resolve it into an absolute path before moving ahead.
             val relativeComponents = Components.parse(path)
             val absoluteComponents =
                 resolveRelativePath(relativeComponents, workingDirectory.components)
 
-            media.add(Path(workingDirectory.volume, absoluteComponents))
+            paths.add(Path(workingDirectory.volume, absoluteComponents))
         }
 
-        return media.ifEmpty { null }
+        return if (paths.isNotEmpty()) {
+            ImportedPlaylist(name, paths)
+        } else {
+            // Couldn't get anything useful out of this file.
+            null
+        }
     }
 
     private fun resolveRelativePath(
@@ -66,8 +108,12 @@ class M3UImpl @Inject constructor() : M3U {
         var components = workingDirectory
         for (component in relative.components) {
             when (component) {
+                // Parent specifier, go "back" one directory (in practice cleave off the last
+                // component)
                 ".." -> components = components.parent()
+                // Current directory, the components are already there.
                 "." -> {}
+                // New directory, add it
                 else -> components = components.child(component)
             }
         }

app/src/main/java/org/oxycblt/auxio/music/external/PlaylistImporter.kt

@@ -22,28 +22,42 @@ import android.content.Context
 import android.net.Uri
 import dagger.hilt.android.qualifiers.ApplicationContext
 import javax.inject.Inject
-import org.oxycblt.auxio.music.fs.ContentPathResolver
+import org.oxycblt.auxio.music.fs.DocumentPathFactory
 import org.oxycblt.auxio.music.fs.Path
 import org.oxycblt.auxio.music.fs.contentResolverSafe
 
+/**
+ * Generic playlist file importing abstraction.
+ *
+ * @see ImportedPlaylist
+ * @see M3U
+ * @author Alexander Capehart (OxygenCobalt)
+ */
 interface PlaylistImporter {
     suspend fun import(uri: Uri): ImportedPlaylist?
 }
 
+/**
+ * A playlist that has been imported.
+ *
+ * @property name The name of the playlist. May be null if not provided.
+ * @property paths The paths of the files in the playlist.
+ * @see PlaylistImporter
+ * @see M3U
+ */
 data class ImportedPlaylist(val name: String?, val paths: List<Path>)
 
 class PlaylistImporterImpl
 @Inject
 constructor(
     @ApplicationContext private val context: Context,
-    private val contentPathResolver: ContentPathResolver,
+    private val documentPathFactory: DocumentPathFactory,
     private val m3u: M3U
 ) : PlaylistImporter {
     override suspend fun import(uri: Uri): ImportedPlaylist? {
-        val workingDirectory = contentPathResolver.resolve(uri) ?: return null
+        val filePath = documentPathFactory.unpackDocumentUri(uri) ?: return null
         return context.contentResolverSafe.openInputStream(uri)?.use {
-            val paths = m3u.read(it, workingDirectory) ?: return null
-            return ImportedPlaylist(null, paths)
+            return m3u.read(it, filePath.directory)
         }
     }
 }

app/src/main/java/org/oxycblt/auxio/music/fs/DocumentPathFactory.kt

@@ -22,18 +22,13 @@ import android.net.Uri
 import android.provider.DocumentsContract
 import java.io.File
 import javax.inject.Inject
-import org.oxycblt.auxio.music.fs.Components
-import org.oxycblt.auxio.music.fs.Path
-import org.oxycblt.auxio.music.fs.Volume
-import org.oxycblt.auxio.music.fs.VolumeManager
 
 /**
- * A factory for parsing the reverse-engineered format of the URIs obtained from the document tree
- * (i.e directory) folder.
+ * A factory for parsing the reverse-engineered format of the URIs obtained from document picker.
  *
  * @author Alexander Capehart (OxygenCobalt)
  */
-interface DocumentTreePathFactory {
+interface DocumentPathFactory {
     /**
      * Unpacks a document URI into a [Path] instance, using [fromDocumentId].
      *
@@ -67,8 +62,8 @@ interface DocumentTreePathFactory {
     fun fromDocumentId(path: String): Path?
 }
 
-class DocumentTreePathFactoryImpl @Inject constructor(private val volumeManager: VolumeManager) :
-    DocumentTreePathFactory {
+class DocumentPathFactoryImpl @Inject constructor(private val volumeManager: VolumeManager) :
+    DocumentPathFactory {
     override fun unpackDocumentUri(uri: Uri) = fromDocumentId(DocumentsContract.getDocumentId(uri))
 
     override fun unpackDocumentTreeUri(uri: Uri): Path? {

app/src/main/java/org/oxycblt/auxio/music/fs/FsModule.kt

@@ -21,6 +21,7 @@ package org.oxycblt.auxio.music.fs
 import android.content.ContentResolver
 import android.content.Context
 import android.os.storage.StorageManager
+import dagger.Binds
 import dagger.Module
 import dagger.Provides
 import dagger.hilt.InstallIn
@@ -39,11 +40,14 @@ class FsModule {
     fun mediaStoreExtractor(@ApplicationContext context: Context, volumeManager: VolumeManager) =
         MediaStoreExtractor.from(context, volumeManager)
 
-    @Provides
-    fun contentPathResolver(@ApplicationContext context: Context, volumeManager: VolumeManager) =
-        ContentPathResolver.from(context, volumeManager)
-
     @Provides
     fun contentResolver(@ApplicationContext context: Context): ContentResolver =
         context.contentResolverSafe
 }
+
+@Module
+@InstallIn(SingletonComponent::class)
+interface FsBindsModule {
+    @Binds
+    fun documentPathFactory(documentTreePathFactory: DocumentPathFactoryImpl): DocumentPathFactory
+}

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

@@ -310,6 +310,7 @@
     <string name="err_no_music">No music found</string>
     <string name="err_index_failed">Music loading failed</string>
     <string name="err_no_perms">Auxio needs permission to read your music library</string>
+    <string name="err_import_failed">Could not import a playlist from this file</string>
     <string name="err_no_app">No app found that can handle this task</string>
     <!-- No folders in the "Music Folders" setting -->
     <string name="err_no_dirs">No folders</string>