Signal-Android/src/org/thoughtcrime/securesms/video/ClassicEncryptedMediaDataSo...

55 lines
1.5 KiB
Java

package org.thoughtcrime.securesms.video;
import android.media.MediaDataSource;
import androidx.annotation.NonNull;
import androidx.annotation.RequiresApi;
import org.thoughtcrime.securesms.crypto.AttachmentSecret;
import org.thoughtcrime.securesms.crypto.ClassicDecryptingPartInputStream;
import org.thoughtcrime.securesms.util.Util;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
@RequiresApi(23)
final class ClassicEncryptedMediaDataSource extends MediaDataSource {
private final AttachmentSecret attachmentSecret;
private final File mediaFile;
private final long length;
ClassicEncryptedMediaDataSource(@NonNull AttachmentSecret attachmentSecret, @NonNull File mediaFile, long length) {
this.attachmentSecret = attachmentSecret;
this.mediaFile = mediaFile;
this.length = length;
}
@Override
public int readAt(long position, byte[] bytes, int offset, int length) throws IOException {
try (InputStream inputStream = ClassicDecryptingPartInputStream.createFor(attachmentSecret, mediaFile)) {
byte[] buffer = new byte[4096];
long headerRemaining = position;
while (headerRemaining > 0) {
int read = inputStream.read(buffer, 0, Util.toIntExact(Math.min((long)buffer.length, headerRemaining)));
if (read == -1) return -1;
headerRemaining -= read;
}
return inputStream.read(bytes, offset, length);
}
}
@Override
public long getSize() {
return length;
}
@Override
public void close() {}
}