Revert "third_party/protobuf: Update to HEAD (83d681ee2c)"

third_party/protobuf/java/core/src/main/java/com/google/protobuf/UnsafeByteOperations.java

Index: third_party/protobuf/java/core/src/main/java/com/google/protobuf/UnsafeByteOperations.java
diff --git a/third_party/protobuf/java/core/src/main/java/com/google/protobuf/UnsafeByteOperations.java b/third_party/protobuf/java/core/src/main/java/com/google/protobuf/UnsafeByteOperations.java
index 878c77581663e7d4c2ea40811f43e38d0dd5c0a2..0fbf4d401c404ebd8c4c759cb8c4fd88030a70aa 100644
--- a/third_party/protobuf/java/core/src/main/java/com/google/protobuf/UnsafeByteOperations.java
+++ b/third_party/protobuf/java/core/src/main/java/com/google/protobuf/UnsafeByteOperations.java
@@ -42,23 +42,6 @@ import java.nio.ByteBuffer;
  * guaranteed that the buffer backing the {@link ByteString} will never change! Mutation of a
  * {@link ByteString} can lead to unexpected and undesirable consequences in your application,
  * and will likely be difficult to debug. Proceed with caution!
- *
- * <p>This can have a number of significant side affects that have
- * spooky-action-at-a-distance-like behavior. In particular, if the bytes value changes out from
- * under a Protocol Buffer:
- * <ul>
- * <li>serialization may throw
- * <li>serialization may succeed but the wrong bytes may be written out
- * <li>messages are no longer threadsafe
- * <li>hashCode may be incorrect
- *   <ul>
- *   <li>can result in a permanent memory leak when used as a key in a long-lived HashMap
- *   <li> the semantics of many programs may be violated if this is the case
- *   </ul>
- * </ul>
- * Each of these issues will occur in parts of the code base that are entirely distinct from the
- * parts of the code base modifying the buffer. In fact, both parts of the code base may be correct
- * - it is the bridging with the unsafe operations that was in error!
  */
 @ExperimentalApi
 public final class UnsafeByteOperations {
@@ -67,34 +50,16 @@ public final class UnsafeByteOperations {
   /**
    * An unsafe operation that returns a {@link ByteString} that is backed by the provided buffer.
    *
-   * @param buffer the buffer to be wrapped
-   * @return a {@link ByteString} backed by the provided buffer
-   */
-  public static ByteString unsafeWrap(byte[] buffer) {
-    return ByteString.wrap(buffer);
-  }
-
-  /**
-   * An unsafe operation that returns a {@link ByteString} that is backed by a subregion of the
-   * provided buffer.
-   *
-   * @param buffer the buffer to be wrapped
-   * @param offset the offset of the wrapped region
-   * @param length the number of bytes of the wrapped region
-   * @return a {@link ByteString} backed by the provided buffer
-   */
-  public static ByteString unsafeWrap(byte[] buffer, int offset, int length) {
-    return ByteString.wrap(buffer, offset, length);
-  }
-
-  /**
-   * An unsafe operation that returns a {@link ByteString} that is backed by the provided buffer.
-   *
    * @param buffer the Java NIO buffer to be wrapped
    * @return a {@link ByteString} backed by the provided buffer
    */
   public static ByteString unsafeWrap(ByteBuffer buffer) {
-    return ByteString.wrap(buffer);
+    if (buffer.hasArray()) {
+      final int offset = buffer.arrayOffset();
+      return ByteString.wrap(buffer.array(), offset + buffer.position(), buffer.remaining());
+    } else {
+      return new NioByteString(buffer);
+    }
   }
 
   /**
@@ -116,5 +81,4 @@ public final class UnsafeByteOperations {
   public static void unsafeWriteTo(ByteString bytes, ByteOutput output) throws IOException {
     bytes.writeTo(output);
   }
-
 }