First steps in reducing dependency on proto from runtime.

- Remove transport.proto and move status codes into Status.java with a little refactoring to make
status easier & more precise to use
- Move DeferredProtoInputStream into a proto subpackage
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=76392172

core/src/main/java/com/google/net/stubby/AbstractOperation.java

@@ -2,7 +2,6 @@ package com.google.net.stubby;
 
 import com.google.common.base.Preconditions;
 import com.google.common.collect.MapMaker;
-import com.google.net.stubby.transport.Transport;
 
 import java.io.InputStream;
 import java.util.concurrent.ConcurrentMap;
@@ -45,7 +44,7 @@ public abstract class AbstractOperation implements Operation {
    */
   protected Operation progressTo(Phase desiredPhase) {
     if (desiredPhase.ordinal() < phase.ordinal()) {
-      close(new Status(Transport.Code.INTERNAL,
+      close(Status.INTERNAL.withDescription(
           "Canot move to " + desiredPhase.name() + " from " + phase.name()));
     } else {
       phase = desiredPhase;

core/src/main/java/com/google/net/stubby/DeferredInputStream.java

@@ -4,12 +4,14 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 
+import javax.annotation.Nullable;
+
 /**
  * Extension to {@link InputStream} to allow for deferred production of data. Allows for
  * zero-copy conversions when the goal is to copy the contents of a resource to a
  * stream or buffer.
  */
-public abstract class DeferredInputStream extends InputStream {
+public abstract class DeferredInputStream<T> extends InputStream {
 
   /**
    * Produce the entire contents of this stream to the specified target
@@ -17,4 +19,11 @@ public abstract class DeferredInputStream extends InputStream {
    * @return number of bytes written
    */
   public abstract int flushTo(OutputStream target) throws IOException;
+
+  /**
+   *  Returns the object that backs the stream. If any bytes have been read from the stream
+   *  then {@code null} is returned.
+   */
+  @Nullable
+  public abstract T getDeferred();
 }

core/src/main/java/com/google/net/stubby/SessionClientStream.java

@@ -3,7 +3,6 @@ package com.google.net.stubby;
 import com.google.net.stubby.newtransport.ClientStream;
 import com.google.net.stubby.newtransport.ClientStreamListener;
 import com.google.net.stubby.newtransport.StreamState;
-import com.google.net.stubby.transport.Transport;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -82,7 +81,7 @@ public class SessionClientStream implements ClientStream {
    */
   @Override
   public void cancel() {
-    request.close(new Status(Transport.Code.CANCELLED));
+    request.close(Status.CANCELLED);
   }
 
   /**

core/src/main/java/com/google/net/stubby/Status.java

@@ -2,9 +2,11 @@ package com.google.net.stubby;
 
 import com.google.common.base.Preconditions;
 import com.google.common.base.Throwables;
-import com.google.net.stubby.transport.Transport;
+import com.google.common.collect.Lists;
 
-import java.util.logging.Logger;
+import java.util.List;
+import java.util.Objects;
+import java.util.TreeMap;
 
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
@@ -13,16 +15,198 @@ import javax.annotation.concurrent.Immutable;
  * Defines the status of an operation using the canonical error space.
  */
 @Immutable
-public class Status {
+public final class Status {
-  public static final Status OK = new Status(Transport.Code.OK);
+
-  public static final Status CANCELLED = new Status(Transport.Code.CANCELLED);
+  /**
-  public static final Metadata.Key<Transport.Code> CODE_KEY
+   * The set of canonical error codes. If new codes are added over time they must choose
-      = Metadata.Key.of("grpc-status", new CodeMarshaller());
+   * a numerical value that does not collide with any previously defined code.
+   */
+  public enum Code {
+    OK(0),
+
+    // The operation was cancelled (typically by the caller).
+    CANCELLED(1),
+
+    // Unknown error.  An example of where this error may be returned is
+    // if a Status value received from another address space belongs to
+    // an error-space that is not known in this address space.  Also
+    // errors raised by APIs that do not return enough error information
+    // may be converted to this error.
+    UNKNOWN(2),
+
+    // Client specified an invalid argument.  Note that this differs
+    // from FAILED_PRECONDITION.  INVALID_ARGUMENT indicates arguments
+    // that are problematic regardless of the state of the system
+    // (e.g., a malformed file name).
+    INVALID_ARGUMENT(3),
+
+    // Deadline expired before operation could complete.  For operations
+    // that change the state of the system, this error may be returned
+    // even if the operation has completed successfully.  For example, a
+    // successful response from a server could have been delayed long
+    // enough for the deadline to expire.
+    DEADLINE_EXCEEDED(4),
+
+    // Some requested entity (e.g., file or directory) was not found.
+    NOT_FOUND(5),
+
+    // Some entity that we attempted to create (e.g., file or directory)
+    // already exists.
+    ALREADY_EXISTS(6),
+
+    // The caller does not have permission to execute the specified
+    // operation.  PERMISSION_DENIED must not be used for rejections
+    // caused by exhausting some resource (use RESOURCE_EXHAUSTED
+    // instead for those errors).  PERMISSION_DENIED must not be
+    // used if the caller cannot be identified (use UNAUTHENTICATED
+    // instead for those errors).
+    PERMISSION_DENIED(7),
+
+    // Some resource has been exhausted, perhaps a per-user quota, or
+    // perhaps the entire file system is out of space.
+    RESOURCE_EXHAUSTED(8),
+
+    // Operation was rejected because the system is not in a state
+    // required for the operation's execution.  For example, directory
+    // to be deleted may be non-empty, an rmdir operation is applied to
+    // a non-directory, etc.
+    //
+    // A litmus test that may help a service implementor in deciding
+    // between FAILED_PRECONDITION, ABORTED, and UNAVAILABLE:
+    //  (a) Use UNAVAILABLE if the client can retry just the failing call.
+    //  (b) Use ABORTED if the client should retry at a higher-level
+    //      (e.g., restarting a read-modify-write sequence).
+    //  (c) Use FAILED_PRECONDITION if the client should not retry until
+    //      the system state has been explicitly fixed.  E.g., if an "rmdir"
+    //      fails because the directory is non-empty, FAILED_PRECONDITION
+    //      should be returned since the client should not retry unless
+    //      they have first fixed up the directory by deleting files from it.
+    FAILED_PRECONDITION(9),
+
+    // The operation was aborted, typically due to a concurrency issue
+    // like sequencer check failures, transaction aborts, etc.
+    //
+    // See litmus test above for deciding between FAILED_PRECONDITION,
+    // ABORTED, and UNAVAILABLE.
+    ABORTED(10),
+
+    // Operation was attempted past the valid range.  E.g., seeking or
+    // reading past end of file.
+    //
+    // Unlike INVALID_ARGUMENT, this error indicates a problem that may
+    // be fixed if the system state changes. For example, a 32-bit file
+    // system will generate INVALID_ARGUMENT if asked to read at an
+    // offset that is not in the range [0,2^32-1], but it will generate
+    // OUT_OF_RANGE if asked to read from an offset past the current
+    // file size.
+    //
+    // There is a fair bit of overlap between FAILED_PRECONDITION and
+    // OUT_OF_RANGE.  We recommend using OUT_OF_RANGE (the more specific
+    // error) when it applies so that callers who are iterating through
+    // a space can easily look for an OUT_OF_RANGE error to detect when
+    // they are done.
+    OUT_OF_RANGE(11),
+
+    // Operation is not implemented or not supported/enabled in this service.
+    UNIMPLEMENTED(12),
+
+    // Internal errors.  Means some invariants expected by underlying
+    // system has been broken.  If you see one of these errors,
+    // something is very broken.
+    INTERNAL(13),
+
+    // The service is currently unavailable.  This is a most likely a
+    // transient condition and may be corrected by retrying with
+    // a backoff.
+    //
+    // See litmus test above for deciding between FAILED_PRECONDITION,
+    // ABORTED, and UNAVAILABLE.
+    UNAVAILABLE(14),
+
+    // Unrecoverable data loss or corruption.
+    DATA_LOSS(15),
+
+    // The request does not have valid authentication credentials for the
+    // operation.
+    UNAUTHENTICATED(16);
+
+    private final int value;
+
+    private Code(int value) {
+      this.value = value;
+    }
+
+    public int value() {
+      return value;
+    }
+    
+    private Status status() {
+      return STATUS_LIST.get(value);
+    }
+  }
+
+  // Create the canonical list of Status instances indexed by their code values.
+  private static List<Status> STATUS_LIST;
+  static {
+    TreeMap<Integer, Status> canonicalizer = new TreeMap<>();
+    for (Code code : Code.values()) {
+      Status replaced = canonicalizer.put(code.value(), new Status(code));
+      if (replaced != null) {
+        throw new IllegalStateException("Code value duplication between " +
+            replaced.getCode().name() + " & " + code.name());
+      }
+    }
+    STATUS_LIST = Lists.newArrayList(canonicalizer.values());
+  }
+
+  // A pseudo-enum of Status instances mapped 1:1 with values in Code. This simplifies construction
+  // patterns for derived implementations of Status.
+  public static final Status OK = Code.OK.status();
+  public static final Status CANCELLED = Code.CANCELLED.status();
+  public static final Status UNKNOWN = Code.UNKNOWN.status();
+  public static final Status INVALID_ARGUMENT = Code.INVALID_ARGUMENT.status();
+  public static final Status DEADLINE_EXCEEDED = Code.DEADLINE_EXCEEDED.status();
+  public static final Status NOT_FOUND = Code.NOT_FOUND.status();
+  public static final Status ALREADY_EXISTS = Code.ALREADY_EXISTS.status();
+  public static final Status PERMISSION_DENIED = Code.PERMISSION_DENIED.status();
+  public static final Status UNAUTHENTICATED = Code.PERMISSION_DENIED.status();
+  public static final Status RESOURCE_EXHAUSTED = Code.RESOURCE_EXHAUSTED.status();
+  public static final Status FAILED_PRECONDITION = 
+      Code.FAILED_PRECONDITION.status();
+  public static final Status ABORTED = Code.ABORTED.status();
+  public static final Status OUT_OF_RANGE = Code.OUT_OF_RANGE.status();
+  public static final Status UNIMPLEMENTED = Code.UNIMPLEMENTED.status();
+  public static final Status INTERNAL = Code.INTERNAL.status();
+  public static final Status UNAVAILABLE = Code.UNAVAILABLE.status();
+  public static final Status DATA_LOSS = Code.DATA_LOSS.status();
+
+  /**
+   * Return a {@link Status} given a canonical error {@link Code} value.
+   */
+  public static Status fromCodeValue(int codeValue) {
+    Status status;
+    if (codeValue < 0 || codeValue > STATUS_LIST.size()) {
+      return UNKNOWN.withDescription("Unknown code " + codeValue);
+    } else {
+      return status = STATUS_LIST.get(codeValue);
+    }
+  }
+
+  /**
+   * Key to bind status code to trailers.
+   */
+  public static final Metadata.Key<Status> CODE_KEY
+      = Metadata.Key.of("grpc-status", new StatusCodeMarshaller());
+
+  /**
+   * Key to bind status message to trailers.
+   */
   public static final Metadata.Key<String> MESSAGE_KEY
       = Metadata.Key.of("grpc-message", Metadata.STRING_MARSHALLER);
 
-  private static final Logger log = Logger.getLogger(Status.class.getName());
+  /**
-
+   * Extract an error {@link Status} from the causal chain of a {@link Throwable}.
+   */
   public static Status fromThrowable(Throwable t) {
     for (Throwable cause : Throwables.getCausalChain(t)) {
       if (cause instanceof OperationException) {
@@ -32,32 +216,44 @@ public class Status {
       }
     }
     // Couldn't find a cause with a Status
-    return new Status(Transport.Code.INTERNAL, t);
+    return INTERNAL.withCause(t);
   }
 
-  private final Transport.Code code;
+  private final Code code;
   private final String description;
   private final Throwable cause;
 
-  public Status(Transport.Code code) {
+  private Status(Code code) {
     this(code, null, null);
   }
 
-  public Status(Transport.Code code, @Nullable String description) {
+  private Status(Code code, @Nullable String description, @Nullable Throwable cause) {
-    this(code, description, null);
-  }
-
-  public Status(Transport.Code code, @Nullable Throwable cause) {
-    this(code, null, cause);
-  }
-
-  public Status(Transport.Code code, @Nullable String description, @Nullable Throwable cause) {
     this.code = Preconditions.checkNotNull(code);
     this.description = description;
     this.cause = cause;
   }
 
-  public Transport.Code getCode() {
+  /**
+   * Create a derived instance of {@link Status} with the given cause.
+   */
+  public Status withCause(Throwable cause) {
+    if (Objects.equals(this.cause, cause)) {
+      return this;
+    }
+    return new Status(this.code, this.description, cause);
+  }
+
+  /**
+   * Create a derived instance of {@link Status} with the given description.
+   */
+  public Status withDescription(String description) {
+    if (Objects.equals(this.description, description)) {
+      return this;
+    }
+    return new Status(this.code, description, this.cause);
+  }
+
+  public Code getCode() {
     return code;
   }
 
@@ -71,25 +267,25 @@ public class Status {
     return cause;
   }
 
+  /**
+   * Is this status OK, i.e. not an error.
+   */
   public boolean isOk() {
-    return OK.getCode() == getCode();
+    return Code.OK == code;
   }
 
   /**
-   * Override this status with another if allowed.
+   * Convert this {@link Status} to a {@link RuntimeException}. Use {@code #fromThrowable}
+   * to recover this {@link Status} instance when the returned exception is in the causal chain.
    */
-  public Status overrideWith(Status newStatus) {
-    if (this.getCode() == Transport.Code.OK || newStatus.code == Transport.Code.OK) {
-      return this;
-    } else {
-      return newStatus;
-    }
-  }
-
   public RuntimeException asRuntimeException() {
     return new OperationRuntimeException(this);
   }
 
+  /**
+   * Convert this {@link Status} to an {@link Exception}. Use {@code #fromThrowable}
+   * to recover this {@link Status} instance when the returned exception is in the causal chain.
+   */
   public Exception asException() {
     return new OperationException(this);
   }
@@ -142,34 +338,25 @@ public class Status {
     return builder.toString();
   }
 
-  private static class CodeMarshaller implements Metadata.Marshaller<Transport.Code> {
+  private static class StatusCodeMarshaller implements Metadata.Marshaller<Status> {
     @Override
-    public byte[] toBytes(Transport.Code value) {
+    public byte[] toBytes(Status status) {
-      return Metadata.INTEGER_MARSHALLER.toBytes(value.getNumber());
+      return Metadata.INTEGER_MARSHALLER.toBytes(status.getCode().value());
     }
 
     @Override
-    public String toAscii(Transport.Code value) {
+    public String toAscii(Status status) {
-      return Metadata.INTEGER_MARSHALLER.toAscii(value.getNumber());
+      return Metadata.INTEGER_MARSHALLER.toAscii(status.getCode().value());
     }
 
     @Override
-    public Transport.Code parseBytes(byte[] serialized) {
+    public Status parseBytes(byte[] serialized) {
-      return intToCode(Metadata.INTEGER_MARSHALLER.parseBytes(serialized));
+      return fromCodeValue(Metadata.INTEGER_MARSHALLER.parseBytes(serialized));
     }
 
     @Override
-    public Transport.Code parseAscii(String ascii) {
+    public Status parseAscii(String ascii) {
-      return intToCode(Metadata.INTEGER_MARSHALLER.parseAscii(ascii));
+      return fromCodeValue(Metadata.INTEGER_MARSHALLER.parseAscii(ascii));
-    }
-
-    private Transport.Code intToCode(Integer i) {
-      Transport.Code code = Transport.Code.valueOf(i);
-      if (code == null) {
-        log.warning("Unknown Code: " + i);
-        code = Transport.Code.UNKNOWN;
-      }
-      return code;
     }
   }
 }

core/src/main/java/com/google/net/stubby/http/ServletSession.java

@@ -12,7 +12,6 @@ import com.google.net.stubby.Session;
 import com.google.net.stubby.Status;
 import com.google.net.stubby.transport.Framer;
 import com.google.net.stubby.transport.MessageFramer;
-import com.google.net.stubby.transport.Transport;
 import com.google.net.stubby.transport.TransportFrameUtil;
 
 import java.io.ByteArrayOutputStream;
@@ -156,7 +155,7 @@ public class ServletSession extends HttpServlet {
       try {
         responseStream.write(TransportFrameUtil.NO_COMPRESS_FLAG);
       } catch (IOException ioe) {
-        close(new Status(Transport.Code.INTERNAL, ioe));
+        close(Status.INTERNAL.withCause(ioe));
       }
     }
 
@@ -188,7 +187,7 @@ public class ServletSession extends HttpServlet {
         frame.position(1);
         ByteBuffers.asByteSource(frame).copyTo(responseStream);
       } catch (Throwable t) {
-        close(new Status(Transport.Code.INTERNAL, t));
+        close(Status.INTERNAL.withCause(t));
       } finally {
         if (closed && endOfMessage) {
           framer.close();

core/src/main/java/com/google/net/stubby/http/UrlConnectionClientSession.java

@@ -9,7 +9,6 @@ import com.google.net.stubby.Session;
 import com.google.net.stubby.Status;
 import com.google.net.stubby.transport.Framer;
 import com.google.net.stubby.transport.MessageFramer;
-import com.google.net.stubby.transport.Transport;
 
 import java.io.DataOutputStream;
 import java.io.IOException;
@@ -101,7 +100,7 @@ public class UrlConnectionClientSession implements Session {
           connection.disconnect();
         }
       } catch (IOException ioe) {
-        close(new Status(Transport.Code.INTERNAL, ioe));
+        close(Status.INTERNAL.withCause(ioe));
       }
     }
   }

core/src/main/java/com/google/net/stubby/http2/netty/Http2Codec.java

@@ -10,7 +10,6 @@ import com.google.net.stubby.Response;
 import com.google.net.stubby.Session;
 import com.google.net.stubby.Status;
 import com.google.net.stubby.transport.MessageFramer;
-import com.google.net.stubby.transport.Transport.Code;
 
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelFuture;
@@ -111,7 +110,7 @@ public class Http2Codec extends AbstractHttp2ConnectionHandler {
         operation = serverStart(ctx, streamId, headers);
         if (operation == null) {
           closeWithError(new NoOpRequest(createResponse(new Http2Writer(ctx), streamId).build()),
-              new Status(Code.NOT_FOUND));
+              Status.NOT_FOUND);
         }
       }
     }
@@ -131,7 +130,7 @@ public class Http2Codec extends AbstractHttp2ConnectionHandler {
       throws Http2Exception {
     Request request = requestRegistry.lookup(streamId);
     if (request != null) {
-      closeWithError(request, new Status(Code.CANCELLED, "Stream reset"));
+      closeWithError(request, Status.CANCELLED.withDescription("Stream reset"));
       requestRegistry.remove(streamId);
     }
   }

core/src/main/java/com/google/net/stubby/http2/netty/Http2Operation.java

@@ -4,14 +4,13 @@ import com.google.net.stubby.AbstractOperation;
 import com.google.net.stubby.Operation;
 import com.google.net.stubby.Status;
 import com.google.net.stubby.transport.Framer;
-import com.google.net.stubby.transport.Transport;
-
-import java.io.InputStream;
-import java.nio.ByteBuffer;
 
 import io.netty.buffer.Unpooled;
 import io.netty.channel.ChannelFuture;
 
+import java.io.InputStream;
+import java.nio.ByteBuffer;
+
 /**
  * Base implementation of {@link Operation} that writes HTTP2 frames
  */
@@ -55,7 +54,7 @@ abstract class Http2Operation extends AbstractOperation implements Framer.Sink {
         channelFuture.get();
       }
     } catch (Exception e) {
-      close(new Status(Transport.Code.INTERNAL, e));
+      close(Status.INTERNAL.withCause(e));
     } finally {
       if (closed) {
         framer.close();

core/src/main/java/com/google/net/stubby/http2/okhttp/Http2Operation.java

@@ -5,7 +5,6 @@ import com.google.net.stubby.AbstractOperation;
 import com.google.net.stubby.Operation;
 import com.google.net.stubby.Status;
 import com.google.net.stubby.transport.Framer;
-import com.google.net.stubby.transport.Transport;
 
 import com.squareup.okhttp.internal.spdy.FrameWriter;
 
@@ -58,7 +57,7 @@ abstract class Http2Operation extends AbstractOperation implements Framer.Sink {
       frameWriter.data(closed && endOfMessage, getId(), buffer);
       frameWriter.flush();
     } catch (IOException ioe) {
-      close(new Status(Transport.Code.INTERNAL, ioe));
+      close(Status.INTERNAL.withCause(ioe));
     } finally {
       if (closed && endOfMessage) {
         framer.close();

core/src/main/java/com/google/net/stubby/http2/okhttp/Http2Request.java

@@ -7,7 +7,6 @@ import com.google.net.stubby.Response;
 import com.google.net.stubby.Status;
 import com.google.net.stubby.newtransport.okhttp.Headers;
 import com.google.net.stubby.transport.Framer;
-import com.google.net.stubby.transport.Transport;
 
 import com.squareup.okhttp.internal.spdy.FrameWriter;
 import com.squareup.okhttp.internal.spdy.Header;
@@ -37,7 +36,7 @@ public class Http2Request extends Http2Operation implements Request {
           Headers.createRequestHeaders(headers, defaultPath, defaultAuthority);
       frameWriter.synStream(false, false, getId(), 0, requestHeaders);
     } catch (IOException ioe) {
-      close(new Status(Transport.Code.UNKNOWN, ioe));
+      close(Status.UNKNOWN.withCause(ioe));
     }
   }
 

core/src/main/java/com/google/net/stubby/http2/okhttp/Http2Response.java

@@ -4,7 +4,6 @@ import com.google.net.stubby.Response;
 import com.google.net.stubby.Status;
 import com.google.net.stubby.newtransport.okhttp.Headers;
 import com.google.net.stubby.transport.Framer;
-import com.google.net.stubby.transport.Transport;
 
 import com.squareup.okhttp.internal.spdy.FrameWriter;
 
@@ -35,7 +34,7 @@ public class Http2Response extends Http2Operation implements Response {
     try {
       frameWriter.synStream(false, false, getId(), 0, Headers.createResponseHeaders());
     } catch (IOException ioe) {
-      close(new Status(Transport.Code.INTERNAL, ioe));
+      close(Status.INTERNAL.withCause(ioe));
     }
   }
 }

core/src/main/java/com/google/net/stubby/http2/okhttp/OkHttpSession.java

@@ -14,8 +14,6 @@ import com.google.net.stubby.Session;
 import com.google.net.stubby.Status;
 import com.google.net.stubby.transport.InputStreamDeframer;
 import com.google.net.stubby.transport.MessageFramer;
-import com.google.net.stubby.transport.Transport;
-import com.google.net.stubby.transport.Transport.Code;
 
 import com.squareup.okhttp.internal.spdy.ErrorCode;
 import com.squareup.okhttp.internal.spdy.FrameReader;
@@ -46,22 +44,22 @@ public class OkHttpSession implements Session {
   private static final ImmutableMap<ErrorCode, Status> ERROR_CODE_TO_STATUS = ImmutableMap
       .<ErrorCode, Status>builder()
       .put(ErrorCode.NO_ERROR, Status.OK)
-      .put(ErrorCode.PROTOCOL_ERROR, new Status(Transport.Code.INTERNAL, "Protocol error"))
+      .put(ErrorCode.PROTOCOL_ERROR, Status.INTERNAL.withDescription("Protocol error"))
-      .put(ErrorCode.INVALID_STREAM, new Status(Transport.Code.INTERNAL, "Invalid stream"))
+      .put(ErrorCode.INVALID_STREAM, Status.INTERNAL.withDescription("Invalid stream"))
       .put(ErrorCode.UNSUPPORTED_VERSION,
-          new Status(Transport.Code.INTERNAL, "Unsupported version"))
+          Status.INTERNAL.withDescription("Unsupported version"))
-      .put(ErrorCode.STREAM_IN_USE, new Status(Transport.Code.INTERNAL, "Stream in use"))
+      .put(ErrorCode.STREAM_IN_USE, Status.INTERNAL.withDescription("Stream in use"))
       .put(ErrorCode.STREAM_ALREADY_CLOSED,
-          new Status(Transport.Code.INTERNAL, "Stream already closed"))
+          Status.INTERNAL.withDescription("Stream already closed"))
-      .put(ErrorCode.INTERNAL_ERROR, new Status(Transport.Code.INTERNAL, "Internal error"))
+      .put(ErrorCode.INTERNAL_ERROR, Status.INTERNAL.withDescription("Internal error"))
-      .put(ErrorCode.FLOW_CONTROL_ERROR, new Status(Transport.Code.INTERNAL, "Flow control error"))
+      .put(ErrorCode.FLOW_CONTROL_ERROR, Status.INTERNAL.withDescription("Flow control error"))
-      .put(ErrorCode.STREAM_CLOSED, new Status(Transport.Code.INTERNAL, "Stream closed"))
+      .put(ErrorCode.STREAM_CLOSED, Status.INTERNAL.withDescription("Stream closed"))
-      .put(ErrorCode.FRAME_TOO_LARGE, new Status(Transport.Code.INTERNAL, "Frame too large"))
+      .put(ErrorCode.FRAME_TOO_LARGE, Status.INTERNAL.withDescription("Frame too large"))
-      .put(ErrorCode.REFUSED_STREAM, new Status(Transport.Code.INTERNAL, "Refused stream"))
+      .put(ErrorCode.REFUSED_STREAM, Status.INTERNAL.withDescription("Refused stream"))
-      .put(ErrorCode.CANCEL, new Status(Transport.Code.CANCELLED, "Cancelled"))
+      .put(ErrorCode.CANCEL, Status.CANCELLED.withDescription("Cancelled"))
-      .put(ErrorCode.COMPRESSION_ERROR, new Status(Transport.Code.INTERNAL, "Compression error"))
+      .put(ErrorCode.COMPRESSION_ERROR, Status.INTERNAL.withDescription("Compression error"))
       .put(ErrorCode.INVALID_CREDENTIALS,
-          new Status(Transport.Code.PERMISSION_DENIED, "Invalid credentials"))
+          Status.PERMISSION_DENIED.withDescription("Invalid credentials"))
       .build();
 
   public static Session startClient(Socket socket, RequestRegistry requestRegistry,
@@ -200,7 +198,7 @@ public class OkHttpSession implements Session {
         }
       } catch (Throwable ioe) {
         ioe.printStackTrace();
-        closeAllRequests(new Status(Code.INTERNAL, ioe.getMessage()));
+        closeAllRequests(Status.INTERNAL.withCause(ioe));
       } finally {
         // Restore the original thread name.
         Thread.currentThread().setName(threadName);

core/src/main/java/com/google/net/stubby/newtransport/AbstractClientStream.java

@@ -53,7 +53,8 @@ public abstract class AbstractClientStream extends AbstractStream implements Cli
    */
   public void stashTrailers(Metadata.Trailers trailers) {
     Preconditions.checkNotNull(status, "trailers");
-    stashedStatus = new Status(trailers.get(Status.CODE_KEY), trailers.get(Status.MESSAGE_KEY));
+    stashedStatus = trailers.get(Status.CODE_KEY)
+        .withDescription(trailers.get(Status.MESSAGE_KEY));
     trailers.removeAll(Status.CODE_KEY);
     trailers.removeAll(Status.MESSAGE_KEY);
     stashedTrailers = trailers;

core/src/main/java/com/google/net/stubby/newtransport/AbstractServerStream.java

@@ -8,7 +8,6 @@ import com.google.common.base.Preconditions;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.net.stubby.Metadata;
 import com.google.net.stubby.Status;
-import com.google.net.stubby.transport.Transport;
 
 import java.io.InputStream;
 import java.nio.ByteBuffer;
@@ -61,7 +60,7 @@ public abstract class AbstractServerStream extends AbstractStream implements Ser
     gracefulClose = true;
     trailers.removeAll(Status.CODE_KEY);
     trailers.removeAll(Status.MESSAGE_KEY);
-    trailers.put(Status.CODE_KEY, status.getCode());
+    trailers.put(Status.CODE_KEY, status);
     if (status.getDescription() != null) {
       trailers.put(Status.MESSAGE_KEY, status.getDescription());
     }
@@ -114,7 +113,7 @@ public abstract class AbstractServerStream extends AbstractStream implements Ser
       listenerClosed = true;
     }
     if (!gracefulClose) {
-      listener.closed(new Status(Transport.Code.INTERNAL, "successful complete() without close()"));
+      listener.closed(Status.INTERNAL.withDescription("successful complete() without close()"));
       throw new IllegalStateException("successful complete() without close()");
     }
     listener.closed(Status.OK);

core/src/main/java/com/google/net/stubby/newtransport/Deframer.java

@@ -4,7 +4,6 @@ import com.google.common.io.ByteStreams;
 import com.google.net.stubby.GrpcFramingUtil;
 import com.google.net.stubby.Operation;
 import com.google.net.stubby.Status;
-import com.google.net.stubby.transport.Transport;
 
 import java.io.ByteArrayInputStream;
 import java.io.DataInputStream;
@@ -37,7 +36,7 @@ public abstract class Deframer<F> implements Framer.Sink<F> {
     int remaining = internalDeliverFrame(frame);
     if (endOfStream) {
       if (remaining > 0) {
-        writeStatus(new Status(Transport.Code.UNKNOWN, "EOF on incomplete frame"));
+        writeStatus(Status.UNKNOWN.withDescription("EOF on incomplete frame"));
       } else if (!statusDelivered) {
         writeStatus(Status.OK);
       }
@@ -90,16 +89,9 @@ public abstract class Deframer<F> implements Framer.Sink<F> {
             inFrame = false;
           }
         } else if (GrpcFramingUtil.isStatusFrame(currentFlags)) {
-          int status = framedChunk.read() << 8 | framedChunk.read();
+          int code = framedChunk.read() << 8 | framedChunk.read();
-          Transport.Code code = Transport.Code.valueOf(status);
-          // TODO(user): Resolve what to do with remainder of framedChunk
           try {
-            if (code == null) {
+            writeStatus(Status.fromCodeValue(code));
-              // Log for unknown code
-              writeStatus(new Status(Transport.Code.UNKNOWN, "Unknown status code " + status));
-            } else {
-              writeStatus(new Status(code));
-            }
           } finally {
             currentLength = LENGTH_NOT_SET;
             inFrame = false;
@@ -111,7 +103,7 @@ public abstract class Deframer<F> implements Framer.Sink<F> {
         }
       }
     } catch (IOException ioe) {
-      Status status = new Status(Transport.Code.UNKNOWN, ioe);
+      Status status = Status.UNKNOWN.withCause(ioe);
       writeStatus(status);
       throw status.asRuntimeException();
     }

core/src/main/java/com/google/net/stubby/newtransport/GrpcDeframer.java

@@ -8,9 +8,7 @@ import static com.google.net.stubby.GrpcFramingUtil.STATUS_FRAME;
 
 import com.google.common.base.Preconditions;
 import com.google.common.util.concurrent.ListenableFuture;
-import com.google.net.stubby.Metadata;
 import com.google.net.stubby.Status;
-import com.google.net.stubby.transport.Transport;
 
 import java.io.Closeable;
 import java.util.concurrent.Executor;
@@ -215,10 +213,7 @@ public class GrpcDeframer implements Closeable {
    */
   private void processStatus() {
     try {
-      int statusCode = nextFrame.readUnsignedShort();
+      notifyStatus(Status.fromCodeValue(nextFrame.readUnsignedShort()));
-      Transport.Code code = Transport.Code.valueOf(statusCode);
-      notifyStatus(code != null ? new Status(code)
-          : new Status(Transport.Code.UNKNOWN, "Unknown status code " + statusCode));
     } finally {
       nextFrame.close();
       nextFrame = null;

core/src/main/java/com/google/net/stubby/newtransport/HttpUtil.java

@@ -1,6 +1,6 @@
 package com.google.net.stubby.newtransport;
 
-import com.google.net.stubby.transport.Transport;
+import com.google.net.stubby.Status;
 
 import java.net.HttpURLConnection;
 
@@ -38,29 +38,29 @@ public final class HttpUtil {
   /**
    * Maps HTTP error response status codes to transport codes.
    */
-  public static Transport.Code httpStatusToTransportCode(int httpStatusCode) {
+  public static Status httpStatusToGrpcStatus(int httpStatusCode) {
     // Specific HTTP code handling.
     switch (httpStatusCode) {
       case HttpURLConnection.HTTP_UNAUTHORIZED: // 401
-        return Transport.Code.UNAUTHENTICATED;
+        return Status.UNAUTHENTICATED;
       case HttpURLConnection.HTTP_FORBIDDEN: // 403
-        return Transport.Code.PERMISSION_DENIED;
+        return Status.PERMISSION_DENIED;
       default:
     }
     // Generic HTTP code handling.
     if (httpStatusCode < 300) {
-      return Transport.Code.OK;
+      return Status.OK;
     }
     if (httpStatusCode < 400) {
-      return Transport.Code.UNAVAILABLE;
+      return Status.UNAVAILABLE;
     }
     if (httpStatusCode < 500) {
-      return Transport.Code.INVALID_ARGUMENT;
+      return Status.INVALID_ARGUMENT;
     }
     if (httpStatusCode < 600) {
-      return Transport.Code.FAILED_PRECONDITION;
+      return Status.FAILED_PRECONDITION;
     }
-    return Transport.Code.INTERNAL;
+    return Status.INTERNAL;
   }
 
   private HttpUtil() {}

core/src/main/java/com/google/net/stubby/newtransport/MessageDeframer2.java

@@ -6,8 +6,8 @@ import com.google.common.util.concurrent.ListenableFuture;
 
 import java.io.ByteArrayInputStream;
 import java.io.Closeable;
-import java.io.InputStream;
 import java.io.IOException;
+import java.io.InputStream;
 import java.util.concurrent.Executor;
 import java.util.zip.GZIPInputStream;
 

core/src/main/java/com/google/net/stubby/newtransport/MessageFramer.java

@@ -49,7 +49,7 @@ public class MessageFramer implements Framer {
   @Override
   public void writeStatus(Status status) {
     verifyNotClosed();
-    short code = (short) status.getCode().getNumber();
+    short code = (short) status.getCode().value();
     scratch.clear();
     scratch.put(GrpcFramingUtil.STATUS_FRAME);
     int length = 2;

core/src/main/java/com/google/net/stubby/newtransport/http/HttpClientTransport.java

@@ -16,7 +16,6 @@ import com.google.net.stubby.newtransport.ClientStream;
 import com.google.net.stubby.newtransport.ClientStreamListener;
 import com.google.net.stubby.newtransport.InputStreamDeframer;
 import com.google.net.stubby.newtransport.StreamState;
-import com.google.net.stubby.transport.Transport;
 
 import java.io.DataOutputStream;
 import java.io.IOException;
@@ -142,7 +141,7 @@ public class HttpClientTransport extends AbstractClientTransport {
           }
         }
       } catch (IOException ioe) {
-        setStatus(new Status(Transport.Code.INTERNAL, ioe), new Metadata.Trailers());
+        setStatus(Status.INTERNAL.withCause(ioe), new Metadata.Trailers());
       }
     }
 

core/src/main/java/com/google/net/stubby/newtransport/netty/NettyClientHandler.java

@@ -5,7 +5,6 @@ import static com.google.net.stubby.newtransport.netty.NettyClientStream.PENDING
 import com.google.common.base.Preconditions;
 import com.google.net.stubby.Metadata;
 import com.google.net.stubby.Status;
-import com.google.net.stubby.transport.Transport;
 
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelFuture;
@@ -34,7 +33,7 @@ import java.util.Iterator;
  * the context of the Netty Channel thread.
  */
 class NettyClientHandler extends AbstractHttp2ConnectionHandler {
-  private static final Status GOAWAY_STATUS = new Status(Transport.Code.UNAVAILABLE);
+  private static final Status GOAWAY_STATUS = Status.UNAVAILABLE;
 
   /**
    * A pending stream creation.
@@ -144,7 +143,7 @@ class NettyClientHandler extends AbstractHttp2ConnectionHandler {
     // TODO(user): do something with errorCode?
     Http2Stream http2Stream = connection().requireStream(streamId);
     NettyClientStream stream = clientStream(http2Stream);
-    stream.setStatus(new Status(Transport.Code.UNKNOWN), new Metadata.Trailers());
+    stream.setStatus(Status.UNKNOWN, new Metadata.Trailers());
   }
 
   /**
@@ -389,7 +388,7 @@ class NettyClientHandler extends AbstractHttp2ConnectionHandler {
       case RESERVED_REMOTE:
         // Disallowed state, terminate the stream.
         clientStream(stream).setStatus(
-            new Status(Transport.Code.INTERNAL, "Stream in invalid state: " + stream.state()),
+            Status.INTERNAL.withDescription("Stream in invalid state: " + stream.state()),
             new Metadata.Trailers());
         writeRstStream(ctx(), stream.id(), Http2Error.INTERNAL_ERROR.code(), ctx().newPromise());
         ctx().flush();

core/src/main/java/com/google/net/stubby/newtransport/netty/NettyClientStream.java

@@ -15,7 +15,6 @@ import com.google.net.stubby.newtransport.ClientStreamListener;
 import com.google.net.stubby.newtransport.GrpcDeframer;
 import com.google.net.stubby.newtransport.HttpUtil;
 import com.google.net.stubby.newtransport.MessageDeframer2;
-import com.google.net.stubby.transport.Transport;
 
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.Channel;
@@ -39,7 +38,7 @@ class NettyClientStream extends AbstractClientStream implements NettyStream {
   private final GrpcDeframer deframer;
   private final MessageDeframer2 deframer2;
   private final WindowUpdateManager windowUpdateManager;
-  private Transport.Code responseCode = Transport.Code.UNKNOWN;
+  private Status responseStatus = Status.UNKNOWN;
   private boolean isGrpcResponse;
   private StringBuilder nonGrpcErrorMessage = new StringBuilder();
 
@@ -83,15 +82,15 @@ class NettyClientStream extends AbstractClientStream implements NettyStream {
    * Called in the channel thread to process headers received from the server.
    */
   public void inboundHeadersRecieved(Http2Headers headers, boolean endOfStream) {
-    responseCode = responseCode(headers, responseCode);
+    responseStatus = responseStatus(headers, responseStatus);
-    isGrpcResponse = isGrpcResponse(headers, responseCode);
+    isGrpcResponse = isGrpcResponse(headers, responseStatus);
     if (endOfStream) {
       if (isGrpcResponse) {
         // TODO(user): call stashTrailers() as appropriate, then provide endOfStream to
         // deframer.
-        setStatus(new Status(responseCode), new Metadata.Trailers());
+        setStatus(responseStatus, new Metadata.Trailers());
       } else {
-        setStatus(new Status(responseCode), new Metadata.Trailers());
+        setStatus(responseStatus, new Metadata.Trailers());
       }
     }
   }
@@ -125,7 +124,7 @@ class NettyClientStream extends AbstractClientStream implements NettyStream {
 
       if (endOfStream) {
         String msg = nonGrpcErrorMessage.toString();
-        setStatus(new Status(responseCode, msg), new Metadata.Trailers());
+        setStatus(responseStatus.withDescription(msg), new Metadata.Trailers());
       }
     }
   }
@@ -145,7 +144,7 @@ class NettyClientStream extends AbstractClientStream implements NettyStream {
   /**
    * Determines whether or not the response from the server is a GRPC response.
    */
-  private boolean isGrpcResponse(Http2Headers headers, Transport.Code code) {
+  private boolean isGrpcResponse(Http2Headers headers, Status status) {
     if (isGrpcResponse) {
       // Already verified that it's a gRPC response.
       return true;
@@ -157,7 +156,7 @@ class NettyClientStream extends AbstractClientStream implements NettyStream {
     }
 
     // GRPC responses should always return OK. Updated this code once b/16290036 is fixed.
-    if (code == Transport.Code.OK) {
+    if (status.isOk()) {
       // ESF currently returns the wrong content-type for grpc.
       return true;
     }
@@ -169,7 +168,7 @@ class NettyClientStream extends AbstractClientStream implements NettyStream {
   /**
    * Parses the response status and converts it to a transport code.
    */
-  private Transport.Code responseCode(Http2Headers headers, Transport.Code defaultValue) {
+  private static Status responseStatus(Http2Headers headers, Status defaultValue) {
     if (headers == null) {
       return defaultValue;
     }
@@ -177,9 +176,7 @@ class NettyClientStream extends AbstractClientStream implements NettyStream {
     // First, check to see if we found a v2 protocol grpc-status header.
     AsciiString grpcStatus = headers.get(GRPC_STATUS_HEADER);
     if (grpcStatus != null) {
-      int code = grpcStatus.parseInt();
+      return Status.fromCodeValue(grpcStatus.parseInt());
-      Transport.Code value = Transport.Code.valueOf(code);
-      return value != null ? value : Transport.Code.UNKNOWN;
     }
 
     // Next, check the HTTP/2 status.
@@ -188,6 +185,6 @@ class NettyClientStream extends AbstractClientStream implements NettyStream {
       return defaultValue;
     }
     HttpResponseStatus status = HttpResponseStatus.parseLine(statusLine);
-    return HttpUtil.httpStatusToTransportCode(status.code());
+    return HttpUtil.httpStatusToGrpcStatus(status.code());
   }
 }

core/src/main/java/com/google/net/stubby/newtransport/netty/NettyServerHandler.java

@@ -10,7 +10,6 @@ import com.google.net.stubby.Status;
 import com.google.net.stubby.newtransport.ServerStreamListener;
 import com.google.net.stubby.newtransport.ServerTransportListener;
 import com.google.net.stubby.newtransport.TransportFrameUtil;
-import com.google.net.stubby.transport.Transport;
 
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelFuture;
@@ -43,7 +42,7 @@ class NettyServerHandler extends AbstractHttp2ConnectionHandler {
 
   private static Logger logger = Logger.getLogger(NettyServerHandler.class.getName());
 
-  private static final Status GOAWAY_STATUS = new Status(Transport.Code.UNAVAILABLE);
+  private static final Status GOAWAY_STATUS = Status.UNAVAILABLE;
 
   private final ServerTransportListener transportListener;
   private final DefaultHttp2InboundFlowController inboundFlow;

core/src/main/java/com/google/net/stubby/newtransport/okhttp/OkHttpClientTransport.java

@@ -14,8 +14,6 @@ import com.google.net.stubby.newtransport.ClientStreamListener;
 import com.google.net.stubby.newtransport.ClientTransport;
 import com.google.net.stubby.newtransport.InputStreamDeframer;
 import com.google.net.stubby.newtransport.StreamState;
-import com.google.net.stubby.transport.Transport;
-import com.google.net.stubby.transport.Transport.Code;
 
 import com.squareup.okhttp.internal.spdy.ErrorCode;
 import com.squareup.okhttp.internal.spdy.FrameReader;
@@ -58,30 +56,30 @@ public class OkHttpClientTransport extends AbstractClientTransport {
     Map<ErrorCode, Status> errorToStatus = new HashMap<ErrorCode, Status>();
     errorToStatus.put(ErrorCode.NO_ERROR, Status.OK);
     errorToStatus.put(ErrorCode.PROTOCOL_ERROR,
-        new Status(Transport.Code.INTERNAL, "Protocol error"));
+        Status.INTERNAL.withDescription("Protocol error"));
     errorToStatus.put(ErrorCode.INVALID_STREAM,
-        new Status(Transport.Code.INTERNAL, "Invalid stream"));
+        Status.INTERNAL.withDescription("Invalid stream"));
     errorToStatus.put(ErrorCode.UNSUPPORTED_VERSION,
-        new Status(Transport.Code.INTERNAL, "Unsupported version"));
+        Status.INTERNAL.withDescription("Unsupported version"));
     errorToStatus.put(ErrorCode.STREAM_IN_USE,
-        new Status(Transport.Code.INTERNAL, "Stream in use"));
+        Status.INTERNAL.withDescription("Stream in use"));
     errorToStatus.put(ErrorCode.STREAM_ALREADY_CLOSED,
-        new Status(Transport.Code.INTERNAL, "Stream already closed"));
+        Status.INTERNAL.withDescription("Stream already closed"));
     errorToStatus.put(ErrorCode.INTERNAL_ERROR,
-        new Status(Transport.Code.INTERNAL, "Internal error"));
+        Status.INTERNAL.withDescription("Internal error"));
     errorToStatus.put(ErrorCode.FLOW_CONTROL_ERROR,
-        new Status(Transport.Code.INTERNAL, "Flow control error"));
+        Status.INTERNAL.withDescription("Flow control error"));
     errorToStatus.put(ErrorCode.STREAM_CLOSED,
-        new Status(Transport.Code.INTERNAL, "Stream closed"));
+        Status.INTERNAL.withDescription("Stream closed"));
     errorToStatus.put(ErrorCode.FRAME_TOO_LARGE,
-        new Status(Transport.Code.INTERNAL, "Frame too large"));
+        Status.INTERNAL.withDescription("Frame too large"));
     errorToStatus.put(ErrorCode.REFUSED_STREAM,
-        new Status(Transport.Code.INTERNAL, "Refused stream"));
+        Status.INTERNAL.withDescription("Refused stream"));
-    errorToStatus.put(ErrorCode.CANCEL, new Status(Transport.Code.CANCELLED, "Cancelled"));
+    errorToStatus.put(ErrorCode.CANCEL, Status.CANCELLED.withDescription("Cancelled"));
     errorToStatus.put(ErrorCode.COMPRESSION_ERROR,
-        new Status(Transport.Code.INTERNAL, "Compression error"));
+        Status.INTERNAL.withDescription("Compression error"));
     errorToStatus.put(ErrorCode.INVALID_CREDENTIALS,
-        new Status(Transport.Code.PERMISSION_DENIED, "Invalid credentials"));
+        Status.PERMISSION_DENIED.withDescription("Invalid credentials"));
     ERROR_CODE_TO_STATUS = Collections.unmodifiableMap(errorToStatus);
   }
 
@@ -163,7 +161,7 @@ public class OkHttpClientTransport extends AbstractClientTransport {
       normalClose = !goAway;
     }
     if (normalClose) {
-      abort(new Status(Code.INTERNAL, "Transport stopped"));
+      abort(Status.INTERNAL.withDescription("Transport stopped"));
       // Send GOAWAY with lastGoodStreamId of 0, since we don't expect any server-initiated streams.
       // The GOAWAY is part of graceful shutdown.
       frameWriter.goAway(0, ErrorCode.NO_ERROR, new byte[0]);
@@ -353,7 +351,7 @@ public class OkHttpClientTransport extends AbstractClientTransport {
 
     @Override
     public void goAway(int lastGoodStreamId, ErrorCode errorCode, ByteString debugData) {
-      onGoAway(lastGoodStreamId, new Status(Code.UNAVAILABLE, "Go away"));
+      onGoAway(lastGoodStreamId, Status.UNAVAILABLE.withDescription("Go away"));
     }
 
     @Override
@@ -387,7 +385,7 @@ public class OkHttpClientTransport extends AbstractClientTransport {
     stream.streamId = nextStreamId;
     streams.put(stream.streamId, stream);
     if (nextStreamId >= Integer.MAX_VALUE - 2) {
-      onGoAway(Integer.MAX_VALUE, new Status(Code.INTERNAL, "Stream id exhaust"));
+      onGoAway(Integer.MAX_VALUE, Status.INTERNAL.withDescription("Stream id exhaust"));
     } else {
       nextStreamId += 2;
     }

core/src/main/java/com/google/net/stubby/proto/DeferredProtoInputStream.java

@@ -1,6 +1,7 @@
-package com.google.net.stubby;
+package com.google.net.stubby.proto;
 
 import com.google.common.io.ByteStreams;
+import com.google.net.stubby.DeferredInputStream;
 import com.google.protobuf.CodedOutputStream;
 import com.google.protobuf.MessageLite;
 
@@ -11,9 +12,9 @@ import java.io.OutputStream;
 import javax.annotation.Nullable;
 
 /**
- * Implementation of {@link DeferredInputStream} backed by a protobuf.
+ * Implementation of {@link com.google.net.stubby.DeferredInputStream} backed by a protobuf.
  */
-public class DeferredProtoInputStream extends DeferredInputStream {
+public class DeferredProtoInputStream extends DeferredInputStream<MessageLite> {
 
   // DeferredProtoInputStream 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
@@ -29,7 +30,7 @@ public class DeferredProtoInputStream extends DeferredInputStream {
    * Returns the original protobuf message. Returns null after this stream has been read.
    */
   @Nullable
-  public MessageLite getMessage() {
+  public MessageLite getDeferred() {
     return message;
   }
 

core/src/main/java/com/google/net/stubby/transport/Deframer.java

@@ -74,16 +74,10 @@ public abstract class Deframer<F> {
             inFrame = false;
           }
         } else if (GrpcFramingUtil.isStatusFrame(currentFlags)) {
-          int status = framedChunk.read() << 8 | framedChunk.read();
+          int code = framedChunk.read() << 8 | framedChunk.read();
-          Transport.Code code = Transport.Code.valueOf(status);
           // TODO(user): Resolve what to do with remainder of framedChunk
           try {
-            if (code == null) {
+            target.close(Status.fromCodeValue(code));
-              // Log for unknown code
-              target.close(new Status(Transport.Code.UNKNOWN, "Unknown status code " + status));
-            } else {
-              target.close(new Status(code));
-            }
           } finally {
             currentLength = LENGTH_NOT_SET;
             inFrame = false;
@@ -95,7 +89,7 @@ public abstract class Deframer<F> {
         }
       }
     } catch (IOException ioe) {
-      Status status = new Status(Transport.Code.UNKNOWN, ioe);
+      Status status = Status.UNKNOWN.withCause(ioe);
       target.close(status);
       throw status.asRuntimeException();
     }

core/src/main/java/com/google/net/stubby/transport/MessageFramer.java

@@ -49,7 +49,7 @@ public class MessageFramer implements Framer  {
 
   @Override
   public void writeStatus(Status status, boolean flush, Sink sink) {
-    short code = (short) status.getCode().getNumber();
+    short code = (short) status.getCode().value();
     scratch.clear();
     scratch.put(GrpcFramingUtil.STATUS_FRAME);
     int length = 2;

core/src/test/java/com/google/net/stubby/newtransport/GrpcDeframerTest.java

@@ -15,7 +15,6 @@ import com.google.common.io.ByteStreams;
 import com.google.common.util.concurrent.MoreExecutors;
 import com.google.common.util.concurrent.SettableFuture;
 import com.google.net.stubby.Status;
-import com.google.net.stubby.transport.Transport;
 import com.google.protobuf.ByteString;
 
 import org.junit.Before;
@@ -42,7 +41,7 @@ import javax.annotation.Nullable;
 public class GrpcDeframerTest {
   private static final String MESSAGE = "hello world";
   private static final ByteString MESSAGE_BSTR = ByteString.copyFromUtf8(MESSAGE);
-  private static final Transport.Code STATUS_CODE = Transport.Code.CANCELLED;
+  private static final Status STATUS_CODE = Status.CANCELLED;
 
   private GrpcDeframer reader;
 
@@ -79,7 +78,7 @@ public class GrpcDeframerTest {
     verifyNoStatus();
 
     messageFuture.set(null);
-    verifyStatus(Transport.Code.OK);
+    verifyStatus(Status.Code.OK);
   }
 
   @Test
@@ -107,7 +106,7 @@ public class GrpcDeframerTest {
     writeFrame(PAYLOAD_FRAME, MESSAGE_BSTR.toByteArray(), dos);
 
     // Write a status frame.
-    byte[] statusBytes = new byte[] {0, (byte) STATUS_CODE.getNumber()};
+    byte[] statusBytes = new byte[] {0, (byte) STATUS_CODE.getCode().value()};
     writeFrame(STATUS_FRAME, statusBytes, dos);
 
     // Now write the complete frame: compression header followed by the 3 message frames.
@@ -169,10 +168,10 @@ public class GrpcDeframerTest {
   }
 
   private void verifyStatus() {
-    verifyStatus(Transport.Code.CANCELLED);
+    verifyStatus(Status.Code.CANCELLED);
   }
 
-  private void verifyStatus(Transport.Code code) {
+  private void verifyStatus(Status.Code code) {
     ArgumentCaptor<Status> captor = ArgumentCaptor.forClass(Status.class);
     verify(sink).statusRead(captor.capture());
     verify(sink).endOfStream();
@@ -193,7 +192,7 @@ public class GrpcDeframerTest {
   }
 
   private static byte[] statusFrame() throws IOException {
-    byte[] bytes = new byte[] {0, (byte) STATUS_CODE.getNumber()};
+    byte[] bytes = new byte[] {0, (byte) STATUS_CODE.getCode().value()};
     return frame(STATUS_FRAME, bytes);
   }
 

core/src/test/java/com/google/net/stubby/newtransport/MessageFramerTest.java

@@ -7,7 +7,6 @@ import static org.junit.Assert.assertTrue;
 import com.google.common.primitives.Bytes;
 import com.google.net.stubby.GrpcFramingUtil;
 import com.google.net.stubby.Status;
-import com.google.net.stubby.transport.Transport;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -60,7 +59,7 @@ public class MessageFramerTest {
             new byte[]{0, 0, 0, 2},  // Len is 2 bytes
             new byte[]{0, 13});  // Internal==13
     for (int i = 0; i < 1000; i++) {
-      framer.writeStatus(new Status(Transport.Code.INTERNAL));
+      framer.writeStatus(Status.INTERNAL);
       if ((i + 1) % 13 == 0) {
         framer.flush();
       }

core/src/test/java/com/google/net/stubby/newtransport/netty/NettyClientHandlerTest.java

@@ -19,7 +19,6 @@ import static org.mockito.Mockito.when;
 import com.google.net.stubby.Metadata;
 import com.google.net.stubby.Status;
 import com.google.net.stubby.newtransport.StreamState;
-import com.google.net.stubby.transport.Transport;
 
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
@@ -228,7 +227,7 @@ public class NettyClientHandlerTest extends NettyHandlerTestBase {
     ArgumentCaptor<Status> captor = ArgumentCaptor.forClass(Status.class);
     InOrder inOrder = inOrder(stream);
     inOrder.verify(stream, calls(1)).setStatus(captor.capture(), notNull(Metadata.Trailers.class));
-    assertEquals(Transport.Code.UNAVAILABLE, captor.getValue().getCode());
+    assertEquals(Status.UNAVAILABLE.getCode(), captor.getValue().getCode());
   }
 
   private void setMaxConcurrentStreams(int max) throws Exception {

core/src/test/java/com/google/net/stubby/newtransport/netty/NettyClientStreamTest.java

@@ -14,7 +14,6 @@ import com.google.net.stubby.Metadata;
 import com.google.net.stubby.Status;
 import com.google.net.stubby.newtransport.ClientStreamListener;
 import com.google.net.stubby.newtransport.StreamState;
-import com.google.net.stubby.transport.Transport;
 
 import io.netty.buffer.Unpooled;
 import io.netty.handler.codec.http2.DefaultHttp2Headers;
@@ -73,7 +72,7 @@ public class NettyClientStreamTest extends NettyStreamTestBase {
 
   @Test
   public void setStatusWithErrorShouldCloseStream() {
-    Status errorStatus = new Status(Transport.Code.INTERNAL);
+    Status errorStatus = Status.INTERNAL;
     stream().setStatus(errorStatus, new Metadata.Trailers());
     verify(listener).closed(eq(errorStatus), any(Metadata.Trailers.class));
     assertEquals(StreamState.CLOSED, stream.state());
@@ -81,7 +80,7 @@ public class NettyClientStreamTest extends NettyStreamTestBase {
 
   @Test
   public void setStatusWithOkShouldNotOverrideError() {
-    Status errorStatus = new Status(Transport.Code.INTERNAL);
+    Status errorStatus = Status.INTERNAL;
     stream().setStatus(errorStatus, new Metadata.Trailers());
     stream().setStatus(Status.OK, new Metadata.Trailers());
     verify(listener).closed(any(Status.class), any(Metadata.Trailers.class));
@@ -90,7 +89,7 @@ public class NettyClientStreamTest extends NettyStreamTestBase {
 
   @Test
   public void setStatusWithErrorShouldNotOverridePreviousError() {
-    Status errorStatus = new Status(Transport.Code.INTERNAL);
+    Status errorStatus = Status.INTERNAL;
     stream().setStatus(errorStatus, new Metadata.Trailers());
     stream().setStatus(Status.fromThrowable(new RuntimeException("fake")),
         new Metadata.Trailers());
@@ -115,10 +114,10 @@ public class NettyClientStreamTest extends NettyStreamTestBase {
     // Receive headers first so that it's a valid GRPC response.
     stream().inboundHeadersRecieved(grpcResponseHeaders(), false);
 
-    stream.inboundDataReceived(statusFrame(new Status(Transport.Code.INTERNAL)), false);
+    stream.inboundDataReceived(statusFrame(Status.INTERNAL), false);
     ArgumentCaptor<Status> captor = ArgumentCaptor.forClass(Status.class);
     verify(listener).closed(captor.capture(), any(Metadata.Trailers.class));
-    assertEquals(Transport.Code.INTERNAL, captor.getValue().getCode());
+    assertEquals(Status.INTERNAL.getCode(), captor.getValue().getCode());
     assertEquals(StreamState.CLOSED, stream.state());
   }
 

core/src/test/java/com/google/net/stubby/newtransport/netty/NettyServerStreamTest.java

@@ -12,7 +12,6 @@ import com.google.net.stubby.Metadata;
 import com.google.net.stubby.Status;
 import com.google.net.stubby.newtransport.ServerStreamListener;
 import com.google.net.stubby.newtransport.StreamState;
-import com.google.net.stubby.transport.Transport;
 
 import io.netty.buffer.EmptyByteBuf;
 import io.netty.buffer.UnpooledByteBufAllocator;
@@ -83,7 +82,7 @@ public class NettyServerStreamTest extends NettyStreamTestBase {
 
   @Test
   public void abortStreamAndSendStatus() throws Exception {
-    Status status = new Status(Transport.Code.INTERNAL, new Throwable());
+    Status status = Status.INTERNAL.withCause(new Throwable());
     stream().abortStream(status, true);
     assertEquals(StreamState.CLOSED, stream.state());
     verify(serverListener).closed(same(status));
@@ -93,7 +92,7 @@ public class NettyServerStreamTest extends NettyStreamTestBase {
 
   @Test
   public void abortStreamAndNotSendStatus() throws Exception {
-    Status status = new Status(Transport.Code.INTERNAL, new Throwable());
+    Status status = Status.INTERNAL.withCause(new Throwable());
     stream().abortStream(status, false);
     assertEquals(StreamState.CLOSED, stream.state());
     verify(serverListener).closed(same(status));
@@ -104,7 +103,7 @@ public class NettyServerStreamTest extends NettyStreamTestBase {
 
   @Test
   public void abortStreamAfterClientHalfCloseShouldCallClose() {
-    Status status = new Status(Transport.Code.INTERNAL, new Throwable());
+    Status status = Status.INTERNAL.withCause(new Throwable());
     // Client half-closes. Listener gets halfClosed()
     stream().inboundDataReceived(new EmptyByteBuf(UnpooledByteBufAllocator.DEFAULT), true);
     assertEquals(StreamState.WRITE_ONLY, stream.state());

core/src/test/java/com/google/net/stubby/newtransport/netty/NettyStreamTestBase.java

@@ -26,8 +26,11 @@ import io.netty.buffer.UnpooledByteBufAllocator;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelFutureListener;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelPipeline;
 import io.netty.channel.ChannelPromise;
 import io.netty.channel.EventLoop;
+import io.netty.handler.codec.http2.DefaultHttp2InboundFlowController;
 
 import org.junit.Before;
 import org.junit.Test;
@@ -37,10 +40,6 @@ import org.mockito.MockitoAnnotations;
 import org.mockito.invocation.InvocationOnMock;
 import org.mockito.stubbing.Answer;
 
-import io.netty.handler.codec.http2.DefaultHttp2InboundFlowController;
-import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.ChannelPipeline;
-
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.DataOutputStream;
@@ -157,7 +156,7 @@ public abstract class NettyStreamTestBase {
   protected final ByteBuf statusFrame(Status status) throws Exception {
     ByteArrayOutputStream os = new ByteArrayOutputStream();
     DataOutputStream dos = new DataOutputStream(os);
-    short code = (short) status.getCode().getNumber();
+    short code = (short) status.getCode().value();
     dos.write(STATUS_FRAME);
     int length = 2;
     dos.writeInt(length);

core/src/test/java/com/google/net/stubby/newtransport/okhttp/OkHttpClientTransportTest.java

@@ -9,7 +9,6 @@ import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.reset;
 import static org.mockito.Mockito.verify;
-import static org.mockito.Mockito.verifyZeroInteractions;
 import static org.mockito.Mockito.when;
 
 import com.google.common.util.concurrent.ListenableFuture;
@@ -20,8 +19,6 @@ import com.google.net.stubby.Status;
 import com.google.net.stubby.newtransport.ClientStreamListener;
 import com.google.net.stubby.newtransport.okhttp.OkHttpClientTransport.ClientFrameHandler;
 import com.google.net.stubby.newtransport.okhttp.OkHttpClientTransport.OkHttpClientStream;
-import com.google.net.stubby.transport.Transport;
-import com.google.net.stubby.transport.Transport.Code;
 
 import com.squareup.okhttp.internal.spdy.ErrorCode;
 import com.squareup.okhttp.internal.spdy.FrameReader;
@@ -113,9 +110,9 @@ public class OkHttpClientTransportTest {
     listener1.waitUntilStreamClosed();
     listener2.waitUntilStreamClosed();
     assertEquals(0, streams.size());
-    assertEquals(Code.INTERNAL, listener1.status.getCode());
+    assertEquals(Status.INTERNAL.getCode(), listener1.status.getCode());
     assertEquals(NETWORK_ISSUE_MESSAGE, listener2.status.getCause().getMessage());
-    assertEquals(Code.INTERNAL, listener1.status.getCode());
+    assertEquals(Status.INTERNAL.getCode(), listener1.status.getCode());
     assertEquals(NETWORK_ISSUE_MESSAGE, listener2.status.getCause().getMessage());
     assertTrue("Service state: " + clientTransport.state(),
         Service.State.TERMINATED == clientTransport.state());
@@ -148,11 +145,11 @@ public class OkHttpClientTransportTest {
     clientTransport.newStream(method,new Metadata.Headers(), listener);
     assertTrue(streams.containsKey(3));
     BufferedSource source = mock(BufferedSource.class);
-    InputStream inputStream = createStatusFrame((short) Transport.Code.UNAVAILABLE.getNumber());
+    InputStream inputStream = createStatusFrame((short) Status.UNAVAILABLE.getCode().value());
     when(source.inputStream()).thenReturn(inputStream);
     frameHandler.data(true, 3, source, inputStream.available());
     listener.waitUntilStreamClosed();
-    assertEquals(Transport.Code.UNAVAILABLE, listener.status.getCode());
+    assertEquals(Status.UNAVAILABLE.getCode(), listener.status.getCode());
   }
 
   @Test
@@ -259,8 +256,8 @@ public class OkHttpClientTransportTest {
     listener2.waitUntilStreamClosed();
     verify(frameWriter).goAway(eq(0), eq(ErrorCode.NO_ERROR), (byte[]) any());
     assertEquals(0, streams.size());
-    assertEquals(Code.INTERNAL, listener1.status.getCode());
+    assertEquals(Status.INTERNAL.getCode(), listener1.status.getCode());
-    assertEquals(Code.INTERNAL, listener2.status.getCode());
+    assertEquals(Status.INTERNAL.getCode(), listener2.status.getCode());
     assertEquals(Service.State.TERMINATED, clientTransport.state());
   }
 
@@ -282,7 +279,7 @@ public class OkHttpClientTransportTest {
     // Stream 2 should be closed.
     listener2.waitUntilStreamClosed();
     assertEquals(1, streams.size());
-    assertEquals(Code.UNAVAILABLE, listener2.status.getCode());
+    assertEquals(Status.UNAVAILABLE.getCode(), listener2.status.getCode());
 
     // New stream should be failed.
     MockStreamListener listener3 = new MockStreamListener();

core/src/test/java/com/google/net/stubby/transport/MessageFramerTest.java

@@ -60,7 +60,7 @@ public class MessageFramerTest {
             new byte[]{0, 13});  // Internal==13
     CapturingSink sink = new CapturingSink();
     for (int i = 0; i < 1000; i++) {
-      framer.writeStatus(new Status(Transport.Code.INTERNAL), (i % 17 == 11), sink);
+      framer.writeStatus(Status.INTERNAL, (i % 17 == 11), sink);
       if ((i + 1) % 13 == 0) {
         framer.flush(sink);
       }

stub/src/main/java/com/google/net/stubby/stub/Calls.java

@@ -9,7 +9,6 @@ import com.google.common.util.concurrent.UncheckedExecutionException;
 import com.google.net.stubby.Call;
 import com.google.net.stubby.Metadata;
 import com.google.net.stubby.Status;
-import com.google.net.stubby.transport.Transport;
 
 import java.util.Iterator;
 import java.util.NoSuchElementException;
@@ -249,7 +248,7 @@ public class Calls {
     @Override
     public ListenableFuture<Void> onPayload(RespT value) {
       if (this.value != null) {
-        throw new Status(Transport.Code.INTERNAL, "More than one value received for unary call")
+        throw Status.INTERNAL.withDescription("More than one value received for unary call")
             .asRuntimeException();
       }
       this.value = value;
@@ -262,7 +261,7 @@ public class Calls {
         if (value == null) {
           // No value received so mark the future as an error
           responseFuture.setException(
-              new Status(Transport.Code.INTERNAL, "No value received for unary call")
+              Status.INTERNAL.withDescription("No value received for unary call")
                   .asRuntimeException().fillInStackTrace());
         }
         responseFuture.set(value);

stub/src/main/java/com/google/net/stubby/stub/Marshallers.java

@@ -1,9 +1,8 @@
 package com.google.net.stubby.stub;
 
-import com.google.net.stubby.DeferredProtoInputStream;
 import com.google.net.stubby.Marshaller;
 import com.google.net.stubby.Status;
-import com.google.net.stubby.transport.Transport;
+import com.google.net.stubby.proto.DeferredProtoInputStream;
 import com.google.protobuf.InvalidProtocolBufferException;
 import com.google.protobuf.MessageLite;
 import com.google.protobuf.Parser;
@@ -29,8 +28,8 @@ public class Marshallers {
         try {
           return parser.parseFrom(stream);
         } catch (InvalidProtocolBufferException ipbe) {
-          throw new Status(Transport.Code.INTERNAL, "Invalid protobuf byte sequence", ipbe)
+          throw Status.INTERNAL.withDescription("Invalid protobuf byte sequence")
-              .asRuntimeException();
+            .withCause(ipbe).asRuntimeException();
         }
       }
     };

stub/src/main/java/com/google/net/stubby/stub/StubDescriptor.java

@@ -1,6 +1,6 @@
 package com.google.net.stubby.stub;
 
-import com.google.net.stubby.DeferredProtoInputStream;
+import com.google.net.stubby.proto.DeferredProtoInputStream;
 import com.google.protobuf.InvalidProtocolBufferException;
 import com.google.protobuf.MessageLite;