1 files changed, 159 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/shell/SubprocessBuilder.java b/src/main/java/com/google/devtools/build/lib/shell/SubprocessBuilder.java
new file mode 100644
index 0000000000..0b6ecfb2f5
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/shell/SubprocessBuilder.java
@@ -0,0 +1,159 @@
+// Copyright 2016 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.devtools.build.lib.shell;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.Map;
+
+/**
+ * A builder class that starts a subprocess.
+ */
+public class SubprocessBuilder {
+  /**
+   * What to do with an output stream of the process.
+   */
+  public enum StreamAction {
+    /** Redirect to a file */
+    REDIRECT,
+
+    /** Discard. */
+    DISCARD,
+
+    /** Stream back to the parent process using an output stream. */
+    STREAM };
+
+  private ImmutableList<String> argv;
+  private ImmutableMap<String, String> env;
+  private StreamAction stdoutAction;
+  private File stdoutFile;
+  private StreamAction stderrAction;
+  private File stderrFile;
+  private File workingDirectory;
+
+  public SubprocessBuilder() {
+    stdoutAction = StreamAction.STREAM;
+    stderrAction = StreamAction.STREAM;
+  }
+
+  public ImmutableList<String> getArgv() {
+    return argv;
+  }
+
+  /**
+   * Sets the argv, including argv[0], that is, the binary to execute.
+   */
+  public SubprocessBuilder setArgv(Iterable<String> argv) {
+    this.argv = ImmutableList.copyOf(argv);
+    return this;
+  }
+
+  public ImmutableMap<String, String> getEnv() {
+    return env;
+  }
+
+  /**
+   * Sets the environment passed to the child process. If null, inherit the environment of the
+   * server.
+   */
+  public SubprocessBuilder setEnv(Map<String, String> env) {
+    this.env = env == null
+        ? null : ImmutableMap.copyOf(env);
+    return this;
+  }
+
+  public StreamAction getStdout() {
+    return stdoutAction;
+  }
+
+  public File getStdoutFile() {
+    return stdoutFile;
+  }
+
+  /**
+   * Tells the object what to do with stdout: either stream as a {@code InputStream} or discard.
+   * 
+   * <p>It can also be redirected to a file using {@link #setStdout(File)}.
+   */
+  public SubprocessBuilder setStdout(StreamAction action) {
+    if (action == StreamAction.REDIRECT) {
+      throw new IllegalStateException();
+    }
+    this.stdoutAction = action;
+    this.stdoutFile = null;
+    return this;
+  }
+  
+  /**
+   * Sets the file stdout is appended to. If null, the stdout will be available as an input stream
+   * on the resulting object representing the process.
+   */
+  public SubprocessBuilder setStdout(File file) {
+    this.stdoutAction = StreamAction.REDIRECT;
+    this.stdoutFile = file;
+    return this;
+  }
+
+  public StreamAction getStderr() {
+    return stderrAction;
+  }
+
+  public File getStderrFile() {
+    return stderrFile;
+  }
+
+  /**
+   * Tells the object what to do with stderr: either stream as a {@code InputStream} or discard.
+   * 
+   * <p>It can also be redirected to a file using {@link #setStderr(File)}.
+   */
+  public SubprocessBuilder setStderr(StreamAction action) {
+    if (action == StreamAction.REDIRECT) {
+      throw new IllegalStateException();
+    }
+    this.stderrAction = action;
+    this.stderrFile = null;
+    return this;
+  }
+  
+  /**
+   * Sets the file stderr is appended to. If null, the stderr will be available as an input stream
+   * on the resulting object representing the process.
+   */
+  public SubprocessBuilder setStderr(File file) {
+    this.stderrAction = StreamAction.REDIRECT;
+    this.stderrFile = file;
+    return this;
+  }
+
+  public File getWorkingDirectory() {
+    return workingDirectory;
+  }
+
+  /**
+   * Sets the current working directory. If null, it will be that of this process.
+   */
+  public SubprocessBuilder setWorkingDirectory(File workingDirectory) {
+    this.workingDirectory = workingDirectory;
+    return this;
+  }
+
+  public Subprocess start() throws IOException {
+    return JavaSubprocessFactory.INSTANCE.create(this);
+  }
+}