Add access to process id for both current process and processes started

sdk/lib/io/process.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart.io;
 
 // TODO(ager): The only reason for this class is that we
 // cannot patch a top-level at this point.
 class _ProcessUtils {
   external static _exit(int status);
   external static _setExitCode(int status);
   external static _sleep(int millis);
+  external static int _pid(Process process);
 }
 
 /**
  * Exit the Dart VM process immediately with the given [status] code.
  *
  * This does not wait for any asynchronous operations to terminate. Using
  * [exit] is therefore very likely to lose data.
  */
 void exit(int status) {
   if (status is !int) {
@@ skipping 24 matching lines @@
  */
 void sleep(Duration duration) {
   int milliseconds = duration.inMilliseconds;
   if (milliseconds < 0) {
     throw new ArgumentError("sleep: duration cannot be negative");
   }
   _ProcessUtils._sleep(milliseconds);
 }
 
 /**
+ * Returns the PID if the current process.

[Anders Johnsen, 2013/04/17 09:13:06]

Move to Process.currentPid static getter?

[Søren Gjesse, 2013/04/17 10:15:12]

I think the top level getter fits with the top level exitCode setter.

+ */
+int get pid => _ProcessUtils._pid(null);
+
+/**
  * [Process] is used to start new processes using the static
  * [start] and [run] methods.
  */
 abstract class Process {
   /**
    * Starts a process running the [executable] with the specified
    * [arguments]. Returns a [:Future<Process>:] that completes with a
    * Process instance when the process has been successfully
    * started. That [Process] object can be used to interact with the
    * process. If the process cannot be started the returned [Future]
@@ skipping 44 matching lines @@
 
   /**
    * Returns the standard input stream of the process as an [IOSink].
    *
    * Throws an [UnsupportedError] if the process is
    * non-interactive.
    */
   IOSink get stdin;
 
   /**
+   * Returns the process id of the process.
+   */
+  int get pid;
+
+  /**
    * Returns a [:Future:] which completes with the exit code of the process
    * when the process completes.
    *
    * Throws an [UnsupportedError] if the process is
    * non-interactive.
    */
   Future<int> exitCode;
 
   /**
    * On Windows, [kill] kills the process, ignoring the [signal]
@@ skipping 24 matching lines @@
 
   /**
    * Standard output from the process as a string.
    */
   String get stdout;
 
   /**
    * Standard error from the process as a string.
    */
   String get stderr;
+
+  /**
+   * Process id from the process.
+   */
+  int get pid;
 }
 
 
 /**
  * [ProcessOptions] represents the options that can be supplied when
  * starting a process.
  */
 class ProcessOptions {
   /**
    * The working directory from which the process is started.  Note
@@ skipping 99 matching lines @@
   /**
    * Contains the system message for the process exception if any.
    */
   final String message;
 
   /**
    * Contains the OS error code for the process exception if any.
    */
   final int errorCode;
 }