1 files changed, 137 insertions, 0 deletions
diff --git a/protobuf-nano/src/main/java/io/grpc/protobuf/nano/DeferredNanoProtoInputStream.java b/protobuf-nano/src/main/java/io/grpc/protobuf/nano/DeferredNanoProtoInputStream.java
new file mode 100644
index 000000000..f0aa1af2e
--- /dev/null
+++ b/protobuf-nano/src/main/java/io/grpc/protobuf/nano/DeferredNanoProtoInputStream.java
@@ -0,0 +1,137 @@
+/*
+ * Copyright 2014, Google Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *    * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *    * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *
+ *    * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package io.grpc.protobuf.nano;
+
+import com.google.common.io.ByteStreams;
+import com.google.protobuf.nano.CodedOutputByteBufferNano;
+import com.google.protobuf.nano.MessageNano;
+
+import io.grpc.DeferredInputStream;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+
+import javax.annotation.Nullable;
+
+/**
+ * Implementation of {@link DeferredInputStream} backed by a nano proto.
+ */
+public class DeferredNanoProtoInputStream extends DeferredInputStream<MessageNano> {
+
+  // DeferredNanoProtoInputStream is first initialized with a *message*. *partial* is initially
+  // null.
+  // Once there has been a read operation on this stream, *message* is serialized to *partial* and
+  // set to null.
+  @Nullable private MessageNano message;
+  @Nullable private ByteArrayInputStream partial;
+
+  public DeferredNanoProtoInputStream(MessageNano message) {
+    this.message = message;
+  }
+
+  private void toPartial() {
+    if (message != null) {
+      partial = new ByteArrayInputStream(MessageNano.toByteArray(message));
+      message = null;
+    }
+  }
+
+  @Override
+  public int flushTo(OutputStream target) throws IOException {
+    // TODO(simonma): flushTo is an optimization of DeferredInputStream, for the implementations
+    // that can write data directly to OutputStream, if we don't support flushTo (by not extending
+    // DeferredInputStream), the caller will use ByteStreams.copy anyway. So consider extends
+    // InputStream directly or make a real optimization here (like save the byte[] and use it for a
+    // single target.write()).
+    int written = 0;
+    toPartial();
+    if (partial != null) {
+      written = (int) ByteStreams.copy(partial, target);
+      partial = null;
+    }
+    return written;
+  }
+
+  @Override
+  public int read() throws IOException {
+    toPartial();
+    if (partial != null) {
+      return partial.read();
+    }
+    return -1;
+  }
+
+  @Override
+  public int read(byte[] b, int off, int len) throws IOException {
+    if (message != null) {
+      int size = message.getSerializedSize();
+      if (size == 0) {
+        message = null;
+        partial = null;
+        return -1;
+      }
+      if (len >= size) {
+        // This is the only case that is zero-copy.
+        CodedOutputByteBufferNano output = CodedOutputByteBufferNano.newInstance(b, off, size);
+        message.writeTo(output);
+        output.checkNoSpaceLeft();
+
+        message = null;
+        partial = null;
+        return size;
+      }
+
+      toPartial();
+    }
+    if (partial != null) {
+      return partial.read(b, off, len);
+    }
+    return -1;
+  }
+
+  @Override
+  public int available() throws IOException {
+    if (message != null) {
+      return message.getSerializedSize();
+    } else if (partial != null) {
+      return partial.available();
+    }
+    return 0;
+  }
+
+  @Override
+  @Nullable
+  public MessageNano getDeferred() {
+    return message;
+  }
+}