Let apps provide a custom data source for extractors

Adds android.media.DataSource, which is modeled after its native namesake,
and a new method on MediaExtractor that lets apps specify their implementation
of a DataSource as the source of data for the extractor.

Change-Id: If1b169bd18d2691ebc4f8996494dfc8ee0894b6c

2 files changed, 50 insertions, 0 deletions

diff --git a/media/java/android/media/DataSource.java b/media/java/android/media/DataSource.java
new file mode 100644
index 0000000..347bd5f
--- /dev/null
+++ b/media/java/android/media/DataSource.java
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package android.media;
+
+import java.io.Closeable;
+
+/**
+ * An abstraction for a media data source, e.g. a file or an http stream
+ * {@hide}
+ */
+public interface DataSource extends Closeable {
+    /**
+     * Reads data from the data source at the requested position
+     *
+     * @param offset where in the source to read
+     * @param buffer the buffer to read the data into
+     * @param size how many bytes to read
+     * @return the number of bytes read, or -1 if there was an error
+     */
+    public int readAt(long offset, byte[] buffer, int size);
+
+    /**
+     * Gets the size of the data source.
+     *
+     * @return size of data source, or -1 if the length is unknown
+     */
+    public long getSize();
+}
diff --git a/media/java/android/media/MediaExtractor.java b/media/java/android/media/MediaExtractor.java
index 687d3a5..4b8d3cb 100644
--- a/media/java/android/media/MediaExtractor.java
+++ b/media/java/android/media/MediaExtractor.java
@@ -22,6 +22,7 @@ import android.content.res.AssetFileDescriptor;
 import android.media.MediaCodec;
 import android.media.MediaFormat;
 import android.net.Uri;
+
 import java.io.FileDescriptor;
 import java.io.IOException;
 import java.nio.ByteBuffer;
@@ -60,6 +61,12 @@ final public class MediaExtractor {
     }
 
     /**
+     * Sets the DataSource object to be used as the data source for this extractor
+     * {@hide}
+     */
+    public native final void setDataSource(DataSource source);
+
+    /**
      * Sets the data source as a content Uri.
      *
      * @param context the Context to use when resolving the Uri