Refactor MIDI and Flac extractor loaders for deduplication

Add MIDI filetype information for use in the ExtractorsFactory

PiperOrigin-RevId: 447976272

libraries/common/src/main/java/androidx/media3/common/FileTypes.java

@@ -37,13 +37,14 @@ public final class FileTypes {
   /**
    * File types. One of {@link #UNKNOWN}, {@link #AC3}, {@link #AC4}, {@link #ADTS}, {@link #AMR},
    * {@link #FLAC}, {@link #FLV}, {@link #MATROSKA}, {@link #MP3}, {@link #MP4}, {@link #OGG},
-   * {@link #PS}, {@link #TS}, {@link #WAV}, {@link #WEBVTT} and {@link #JPEG}.
+   * {@link #PS}, {@link #TS}, {@link #WAV}, {@link #WEBVTT}, {@link #JPEG} and {@link #MIDI}.
    */
   @Documented
   @Retention(RetentionPolicy.SOURCE)
   @Target(TYPE_USE)
   @IntDef({
-    UNKNOWN, AC3, AC4, ADTS, AMR, FLAC, FLV, MATROSKA, MP3, MP4, OGG, PS, TS, WAV, WEBVTT, JPEG
+    UNKNOWN, AC3, AC4, ADTS, AMR, FLAC, FLV, MATROSKA, MP3, MP4, OGG, PS, TS, WAV, WEBVTT, JPEG,
+    MIDI
   })
   public @interface Type {}
   /** Unknown file type. */
@@ -78,6 +79,8 @@ public final class FileTypes {
   public static final int WEBVTT = 13;
   /** File type for the JPEG format. */
   public static final int JPEG = 14;
+  /** File type for the MIDI format. */
+  public static final int MIDI = 15;
 
   @VisibleForTesting /* package */ static final String HEADER_CONTENT_TYPE = "Content-Type";
 
@@ -89,6 +92,9 @@ public final class FileTypes {
   private static final String EXTENSION_AMR = ".amr";
   private static final String EXTENSION_FLAC = ".flac";
   private static final String EXTENSION_FLV = ".flv";
+  private static final String EXTENSION_MID = ".mid";
+  private static final String EXTENSION_MIDI = ".midi";
+  private static final String EXTENSION_SMF = ".smf";
   private static final String EXTENSION_PREFIX_MK = ".mk";
   private static final String EXTENSION_WEBM = ".webm";
   private static final String EXTENSION_PREFIX_OG = ".og";
@@ -147,6 +153,8 @@ public final class FileTypes {
         return FileTypes.FLAC;
       case MimeTypes.VIDEO_FLV:
         return FileTypes.FLV;
+      case MimeTypes.AUDIO_MIDI:
+        return FileTypes.MIDI;
       case MimeTypes.VIDEO_MATROSKA:
       case MimeTypes.AUDIO_MATROSKA:
       case MimeTypes.VIDEO_WEBM:
@@ -193,6 +201,10 @@ public final class FileTypes {
       return FileTypes.FLAC;
     } else if (filename.endsWith(EXTENSION_FLV)) {
       return FileTypes.FLV;
+    } else if (filename.endsWith(EXTENSION_MID)
+        || filename.endsWith(EXTENSION_MIDI)
+        || filename.endsWith(EXTENSION_SMF)) {
+      return FileTypes.MIDI;
     } else if (filename.startsWith(
             EXTENSION_PREFIX_MK,
             /* toffset= */ filename.length() - (EXTENSION_PREFIX_MK.length() + 1))

libraries/extractor/src/main/java/androidx/media3/extractor/DefaultExtractorsFactory.java

@@ -44,6 +44,7 @@ import androidx.media3.extractor.ts.TsExtractor;
 import androidx.media3.extractor.ts.TsPayloadReader;
 import androidx.media3.extractor.wav.WavExtractor;
 import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
@@ -76,6 +77,8 @@ import java.util.concurrent.atomic.AtomicBoolean;
  *             the FLAC extension or the FFmpeg extension.
  *       </ul>
  *   <li>JPEG ({@link JpegExtractor})
+ *   <li>MIDI, if available, the MIDI extension's {@code androidx.media3.decoder.midi.MidiExtractor}
+ *       is used.
  * </ul>
  */
 @UnstableApi
@@ -101,9 +104,13 @@ public final class DefaultExtractorsFactory implements ExtractorsFactory {
         FileTypes.AC4,
         FileTypes.MP3,
         FileTypes.JPEG,
+        FileTypes.MIDI,
       };
 
-  private static final FlacExtensionLoader FLAC_EXTENSION_LOADER = new FlacExtensionLoader();
+  private static final ExtensionLoader FLAC_EXTENSION_LOADER =
+      new ExtensionLoader(DefaultExtractorsFactory::getFlacExtractorConstructor);
+  private static final ExtensionLoader MIDI_EXTENSION_LOADER =
+      new ExtensionLoader(DefaultExtractorsFactory::getMidiExtractorConstructor);
 
   private boolean constantBitrateSeekingEnabled;
   private boolean constantBitrateSeekingAlwaysEnabled;
@@ -399,6 +406,12 @@ public final class DefaultExtractorsFactory implements ExtractorsFactory {
       case FileTypes.JPEG:
         extractors.add(new JpegExtractor());
         break;
+      case FileTypes.MIDI:
+        @Nullable Extractor midiExtractor = MIDI_EXTENSION_LOADER.getExtractor();
+        if (midiExtractor != null) {
+          extractors.add(midiExtractor);
+        }
+        break;
       case FileTypes.WEBVTT:
       case FileTypes.UNKNOWN:
       default:
@@ -406,28 +419,63 @@ public final class DefaultExtractorsFactory implements ExtractorsFactory {
     }
   }
 
-  private static final class FlacExtensionLoader {
+  private static Constructor<? extends Extractor> getMidiExtractorConstructor()
+      throws ClassNotFoundException, NoSuchMethodException {
+    return Class.forName("androidx.media3.decoder.midi.MidiExtractor")
+        .asSubclass(Extractor.class)
+        .getConstructor();
+  }
+
+  @Nullable
+  private static Constructor<? extends Extractor> getFlacExtractorConstructor()
+      throws ClassNotFoundException, NoSuchMethodException, InvocationTargetException,
+          IllegalAccessException {
+    @SuppressWarnings("nullness:argument")
+    boolean isFlacNativeLibraryAvailable =
+        Boolean.TRUE.equals(
+            Class.forName("androidx.media3.decoder.flac.FlacLibrary")
+                .getMethod("isAvailable")
+                .invoke(/* obj= */ null));
+    if (isFlacNativeLibraryAvailable) {
+      return Class.forName("androidx.media3.decoder.flac.FlacExtractor")
+          .asSubclass(Extractor.class)
+          .getConstructor(int.class);
+    }
+    return null;
+  }
+
+  private static final class ExtensionLoader {
+
+    public interface ConstructorSupplier {
+      @Nullable
+      Constructor<? extends Extractor> getConstructor()
+          throws InvocationTargetException, IllegalAccessException, NoSuchMethodException,
+              ClassNotFoundException;
+    }
+
+    private final ConstructorSupplier constructorSupplier;
     private final AtomicBoolean extensionLoaded;
 
     @GuardedBy("extensionLoaded")
     @Nullable
     private Constructor<? extends Extractor> extractorConstructor;
 
-    public FlacExtensionLoader() {
+    public ExtensionLoader(ConstructorSupplier constructorSupplier) {
+      this.constructorSupplier = constructorSupplier;
       extensionLoaded = new AtomicBoolean(false);
     }
 
     @Nullable
-    public Extractor getExtractor(int flags) {
+    public Extractor getExtractor(Object... constructorParams) {
       @Nullable
       Constructor<? extends Extractor> extractorConstructor = maybeLoadExtractorConstructor();
       if (extractorConstructor == null) {
         return null;
       }
       try {
-        return extractorConstructor.newInstance(flags);
+        return extractorConstructor.newInstance(constructorParams);
       } catch (Exception e) {
-        throw new IllegalStateException("Unexpected error creating FLAC extractor", e);
+        throw new IllegalStateException("Unexpected error creating extractor", e);
       }
     }
 
@@ -438,23 +486,12 @@ public final class DefaultExtractorsFactory implements ExtractorsFactory {
           return extractorConstructor;
         }
         try {
-          @SuppressWarnings("nullness:argument")
+          return constructorSupplier.getConstructor();
-          boolean isFlacNativeLibraryAvailable =
-              Boolean.TRUE.equals(
-                  Class.forName("androidx.media3.decoder.flac.FlacLibrary")
-                      .getMethod("isAvailable")
-                      .invoke(/* obj= */ null));
-          if (isFlacNativeLibraryAvailable) {
-            extractorConstructor =
-                Class.forName("androidx.media3.decoder.flac.FlacExtractor")
-                    .asSubclass(Extractor.class)
-                    .getConstructor(int.class);
-          }
         } catch (ClassNotFoundException e) {
-          // Expected if the app was built without the FLAC extension.
+          // Expected if the app was built without the extension.
         } catch (Exception e) {
-          // The FLAC extension is present, but instantiation failed.
+          // The extension is present, but instantiation failed.
-          throw new RuntimeException("Error instantiating FLAC extension", e);
+          throw new RuntimeException("Error instantiating extension", e);
         }
         extensionLoaded.set(true);
         return extractorConstructor;