1 files changed, 89 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/upstream/crypto/AesCipherDataSource.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/upstream/crypto/AesCipherDataSource.java
new file mode 100644
index 0000000000..0b0687b57e
--- /dev/null
+++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/upstream/crypto/AesCipherDataSource.java
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2016 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 org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.crypto;
+
+import static org.mozilla.thirdparty.com.google.android.exoplayer2.util.Util.castNonNull;
+
+import android.net.Uri;
+import androidx.annotation.Nullable;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.C;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.DataSource;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.DataSpec;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.TransferListener;
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+import javax.crypto.Cipher;
+
+/**
+ * A {@link DataSource} that decrypts the data read from an upstream source.
+ */
+public final class AesCipherDataSource implements DataSource {
+
+  private final DataSource upstream;
+  private final byte[] secretKey;
+
+  @Nullable private AesFlushingCipher cipher;
+
+  public AesCipherDataSource(byte[] secretKey, DataSource upstream) {
+    this.upstream = upstream;
+    this.secretKey = secretKey;
+  }
+
+  @Override
+  public void addTransferListener(TransferListener transferListener) {
+    upstream.addTransferListener(transferListener);
+  }
+
+  @Override
+  public long open(DataSpec dataSpec) throws IOException {
+    long dataLength = upstream.open(dataSpec);
+    long nonce = CryptoUtil.getFNV64Hash(dataSpec.key);
+    cipher = new AesFlushingCipher(Cipher.DECRYPT_MODE, secretKey, nonce,
+        dataSpec.absoluteStreamPosition);
+    return dataLength;
+  }
+
+  @Override
+  public int read(byte[] data, int offset, int readLength) throws IOException {
+    if (readLength == 0) {
+      return 0;
+    }
+    int read = upstream.read(data, offset, readLength);
+    if (read == C.RESULT_END_OF_INPUT) {
+      return C.RESULT_END_OF_INPUT;
+    }
+    castNonNull(cipher).updateInPlace(data, offset, read);
+    return read;
+  }
+
+  @Override
+  @Nullable
+  public Uri getUri() {
+    return upstream.getUri();
+  }
+
+  @Override
+  public Map<String, List<String>> getResponseHeaders() {
+    return upstream.getResponseHeaders();
+  }
+
+  @Override
+  public void close() throws IOException {
+    cipher = null;
+    upstream.close();
+  }
+}