content: // Copyright 2014 The Bazel Authors. All rights reserved.
  //
  // 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 com.google.android.apps.common.testing.broker.shell;
  
  import static com.google.common.base.Preconditions.checkNotNull;
  
  import java.io.ByteArrayOutputStream;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  
  /**
   * Encapsulates the results of a command execution, including exit status
   * and output to stdout and stderr.
   */
  public final class CommandResult {
  
    private static final Logger log =
      Logger.getLogger("com.google.devtools.build.lib.shell.Command");
  
    private static final byte[] NO_BYTES = new byte[0];
  
    static final ByteArrayOutputStream EMPTY_OUTPUT =
      new ByteArrayOutputStream() {
  
        @Override
        public byte[] toByteArray() {
          return NO_BYTES;
        }
    };
  
    static final ByteArrayOutputStream NO_OUTPUT_COLLECTED =
      new ByteArrayOutputStream(){
  
        @Override
        public byte[] toByteArray() {
          throw new IllegalStateException("Output was not collected");
        }
    };
  
    private final ByteArrayOutputStream stdout;
    private final ByteArrayOutputStream stderr;
    private final TerminationStatus terminationStatus;
  
    CommandResult(final ByteArrayOutputStream stdout,
                  final ByteArrayOutputStream stderr,
                  final TerminationStatus terminationStatus) {
      checkNotNull(stdout);
      checkNotNull(stderr);
      checkNotNull(terminationStatus);
      this.stdout = stdout;
      this.stderr = stderr;
      this.terminationStatus = terminationStatus;
    }
  
    /**
     * @return raw bytes that were written to stdout by the command, or
     *  null if caller did chose to ignore output
     * @throws IllegalStateException if output was not collected
     */
    public byte[] getStdout() {
      return stdout.toByteArray();
    }
  
    /**
     * @return raw bytes that were written to stderr by the command, or
     *  null if caller did chose to ignore output
     * @throws IllegalStateException if output was not collected
     */
    public byte[] getStderr() {
      return stderr.toByteArray();
    }
  
    /**
     * @return the termination status of the subprocess.
     */
    public TerminationStatus getTerminationStatus() {
      return terminationStatus;
    }
  
    void logThis() {
      if (!log.isLoggable(Level.FINER)) {
        return;
      }
      log.finer(terminationStatus.toString());
  
      if (stdout == NO_OUTPUT_COLLECTED) {
        return;
      }
      log.finer("Stdout: " + LogUtil.toTruncatedString(stdout.toByteArray()));
      log.finer("Stderr: " + LogUtil.toTruncatedString(stderr.toByteArray()));
    }
  
  }
  