1 files changed, 132 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/util/io/OutErr.java b/src/main/java/com/google/devtools/build/lib/util/io/OutErr.java
new file mode 100644
index 0000000000..c4700eae77
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/util/io/OutErr.java
@@ -0,0 +1,132 @@
+// Copyright 2014 Google Inc. 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.devtools.build.lib.util.io;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.PrintStream;
+import java.io.PrintWriter;
+
+/**
+ * A pair of output streams to be used for redirecting the output and error
+ * streams of a subprocess.
+ */
+public class OutErr {
+
+  private final OutputStream out;
+  private final OutputStream err;
+
+  public static final OutErr SYSTEM_OUT_ERR = create(System.out, System.err);
+
+  /**
+   * Creates a new OutErr instance from the specified output and error streams.
+   */
+  public static OutErr create(OutputStream out, OutputStream err) {
+    return new OutErr(out, err);
+  }
+
+  protected OutErr(OutputStream out, OutputStream err) {
+    this.out = out;
+    this.err = err;
+  }
+
+  /**
+   * This method redirects {@link System#out} / {@link System#err} into
+   * {@code this} object. After calling this method, writing to
+   * {@link System#out} or {@link System#err} will result in
+   * {@code "System.out: " + message} or {@code "System.err: " + message}
+   * being written to the OutputStreams of {@code this} instance.
+   *
+   * Note: This method affects global variables.
+   */
+  public void addSystemOutErrAsSource() {
+    System.setOut(new PrintStream(new LinePrefixingOutputStream("System.out: ", getOutputStream()),
+                                  /*autoflush=*/false));
+    System.setErr(new PrintStream(new LinePrefixingOutputStream("System.err: ", getErrorStream()),
+                                  /*autoflush=*/false));
+  }
+
+  /**
+   * Creates a new OutErr instance from the specified stream.
+   * Writes to either the output or err of the new OutErr are written
+   * to outputStream, synchronized.
+   */
+  public static OutErr createSynchronizedFunnel(final OutputStream outputStream) {
+    OutputStream syncOut = new OutputStream() {
+
+      @Override
+      public synchronized void write(int b) throws IOException {
+        outputStream.write(b);
+      }
+
+      @Override
+      public synchronized void write(byte b[]) throws IOException {
+        outputStream.write(b);
+      }
+
+      @Override
+      public synchronized  void write(byte b[], int off, int len) throws IOException {
+        outputStream.write(b, off, len);
+      }
+
+      @Override
+      public synchronized void flush() throws IOException {
+        outputStream.flush();
+      }
+
+      @Override
+      public synchronized void close() throws IOException {
+        outputStream.close();
+      }
+    };
+
+    return create(syncOut, syncOut);
+  }
+
+  public OutputStream getOutputStream() {
+    return out;
+  }
+
+  public OutputStream getErrorStream() {
+    return err;
+  }
+
+  /**
+   * Writes the specified string to the output stream, and flushes.
+   */
+  public void printOut(String s) {
+    PrintWriter writer = new PrintWriter(out, true);
+    writer.print(s);
+    writer.flush();
+  }
+
+  public void printOutLn(String s) {
+    printOut(s + "\n");
+  }
+
+  /**
+   * Writes the specified string to the error stream, and flushes.
+   */
+  public void printErr(String s) {
+    PrintWriter writer = new PrintWriter(err, true);
+    writer.print(s);
+    writer.flush();
+  }
+
+  public void printErrLn(String s) {
+    printErr(s + "\n");
+  }
+
+}