Merge "MediaDataSource: address API council comments" into mnc-dev

api/current.txt

@@ -15673,9 +15673,10 @@ package android.media {
     ctor public MediaCryptoException(java.lang.String);
   }
 
-  public abstract interface MediaDataSource implements java.io.Closeable {
-    method public abstract long getSize();
-    method public abstract int readAt(long, byte[], int);
+  public abstract class MediaDataSource implements java.io.Closeable {
+    ctor public MediaDataSource();
+    method public abstract long getSize() throws java.io.IOException;
+    method public abstract int readAt(long, byte[], int, int) throws java.io.IOException;
   }
 
   public class MediaDescription implements android.os.Parcelable {

api/system-current.txt

@@ -16910,9 +16910,10 @@ package android.media {
     ctor public MediaCryptoException(java.lang.String);
   }
 
-  public abstract interface MediaDataSource implements java.io.Closeable {
-    method public abstract long getSize();
-    method public abstract int readAt(long, byte[], int);
+  public abstract class MediaDataSource implements java.io.Closeable {
+    ctor public MediaDataSource();
+    method public abstract long getSize() throws java.io.IOException;
+    method public abstract int readAt(long, byte[], int, int) throws java.io.IOException;
   }
 
   public class MediaDescription implements android.os.Parcelable {

media/java/android/media/MediaDataSource.java

@@ -18,6 +18,7 @@
 package android.media;
 
 import java.io.Closeable;
+import java.io.IOException;
 
 /**
  * For supplying media data to the framework. Implement this if your app has
@@ -29,34 +30,32 @@ import java.io.Closeable;
  * you don't need to do your own synchronization unless you're modifying the
  * MediaDataSource from another thread while it's being used by the framework.</p>
  */
-public interface MediaDataSource extends Closeable {
+public abstract class MediaDataSource implements Closeable {
     /**
      * Called to request data from the given position.
      *
      * Implementations should should write up to {@code size} bytes into
      * {@code buffer}, and return the number of bytes written.
      *
-     * Return {@code 0} to indicate that {@code position} is at, or beyond, the
-     * end of the source.
+     * Return {@code 0} if size is zero (thus no bytes are read).
      *
-     * Return {@code -1} to indicate that a fatal error occurred. The failed
-     * read will not be retried, so transient errors should be handled
-     * internally.
-     *
-     * Throwing an exception from this method will have the same effect as
-     * returning {@code -1}.
+     * Return {@code -1} to indicate that end of stream is reached.
      *
      * @param position the position in the data source to read from.
      * @param buffer the buffer to read the data into.
+     * @param offset the offset within buffer to read the data into.
      * @param size the number of bytes to read.
+     * @throws IOException on fatal errors.
      * @return the number of bytes read, or -1 if there was an error.
      */
-    public int readAt(long position, byte[] buffer, int size);
+    public abstract int readAt(long position, byte[] buffer, int offset, int size)
+            throws IOException;
 
     /**
      * Called to get the size of the data source.
      *
+     * @throws IOException on fatal errors
      * @return the size of data source in bytes, or -1 if the size is unknown.
      */
-    public long getSize();
+    public abstract long getSize() throws IOException;
 }

media/jni/android_media_MediaDataSource.cpp

@@ -39,7 +39,7 @@ JMediaDataSource::JMediaDataSource(JNIEnv* env, jobject source)
     ScopedLocalRef<jclass> mediaDataSourceClass(env, env->GetObjectClass(mMediaDataSourceObj));
     CHECK(mediaDataSourceClass.get() != NULL);
 
-    mReadMethod = env->GetMethodID(mediaDataSourceClass.get(), "readAt", "(J[BI)I");
+    mReadMethod = env->GetMethodID(mediaDataSourceClass.get(), "readAt", "(J[BII)I");
     CHECK(mReadMethod != NULL);
     mGetSizeMethod = env->GetMethodID(mediaDataSourceClass.get(), "getSize", "()J");
     CHECK(mGetSizeMethod != NULL);
@@ -80,7 +80,7 @@ ssize_t JMediaDataSource::readAt(off64_t offset, size_t size) {
 
     JNIEnv* env = AndroidRuntime::getJNIEnv();
     jint numread = env->CallIntMethod(mMediaDataSourceObj, mReadMethod,
-                                      (jlong)offset, mByteArrayObj, (jint)size);
+            (jlong)offset, mByteArrayObj, (jint)0, (jint)size);
     if (env->ExceptionCheck()) {
         ALOGW("An exception occurred in readAt()");
         LOGW_EX(env);
@@ -89,9 +89,14 @@ ssize_t JMediaDataSource::readAt(off64_t offset, size_t size) {
         return -1;
     }
     if (numread < 0) {
-        ALOGW("An error occurred in readAt()");
-        mJavaObjStatus = UNKNOWN_ERROR;
-        return -1;
+        if (numread != -1) {
+            ALOGW("An error occurred in readAt()");
+            mJavaObjStatus = UNKNOWN_ERROR;
+            return -1;
+        } else {
+            // numread == -1 indicates EOF
+            return 0;
+        }
     }
     if ((size_t)numread > size) {
         ALOGE("readAt read too many bytes.");

media/jni/android_media_MediaExtractor.cpp

@@ -715,6 +715,11 @@ static void android_media_MediaExtractor_setDataSourceCallback(
     status_t err = extractor->setDataSource(bridge);
 
     if (err != OK) {
+        // Clear bridge so that JMediaDataSource::close() is called _before_
+        // we throw the IOException.
+        // Otherwise close() gets called when we go out of scope, it calls
+        // Java with a pending exception and crashes the process.
+        bridge.clear();
         jniThrowException(
                 env,
                 "java/io/IOException",