Support passing an environment variable map to child processes.

runtime/bin/process_impl.dart

 // Copyright (c) 2012, 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.
 
 class _ProcessStartStatus {
   int _errorCode;  // Set to OS error code if process start failed.
   String _errorMessage;  // Set to OS error message if process start failed.
 }
 
 
@@ skipping 50 matching lines @@
     }
 
     if (options !== null && options.workingDirectory !== null) {
       _workingDirectory = options.workingDirectory;
       if (_workingDirectory is !String) {
         throw new IllegalArgumentException(
             "WorkingDirectory is not a String: $_workingDirectory");
       }
     }
 
+    if (options !== null && options.environment !== null) {
+      var env = options.environment;
+      if (env is !Map) {
+        throw new IllegalArgumentException("Environment is not a map: $env");
+      }
+      _environment = [];
+      env.forEach((key, value) {
+        if (key is !String || value is !String) {
+          throw new IllegalArgumentException(
+              "Environment key or value is not a string: ($key, $value)");
+        }
+        if (key.contains('=')) {
+          throw new IllegalArgumentException(
+              "Environment keys may not contain '=': $key");
+        }
+        _environment.add('$key=$value');
+      });
+    }
+
     _in = new _Socket._internalReadOnly();  // stdout coming from process.
     _out = new _Socket._internalWriteOnly();  // stdin going to process.
     _err = new _Socket._internalReadOnly();  // stderr coming from process.
     _exitHandler = new _Socket._internalReadOnly();
     _closed = false;
     _killed = false;
     _started = false;
     _onExit = null;
     // TODO(ager): Make the actual process starting really async instead of
     // simulating it with a timer.
@@ skipping 51 matching lines @@
             (bytes[offset + 1] << 8) +
             (bytes[offset + 2] << 16) +
             (bytes[offset + 3] << 24));
   }
 
   void start() {
     var status = new _ProcessStartStatus();
     bool success = _start(_path,
                           _arguments,
                           _workingDirectory,
+                          _environment,
                           _in,
                           _out,
                           _err,
                           _exitHandler,
                           status);
     if (!success) {
       close();
       if (_onError !== null) {
         _onError(new ProcessException(status._errorMessage, status._errorCode));
         return;
@@ skipping 33 matching lines @@
     };
 
     if (_onStart !== null) {
       _onStart();
     }
   }
 
   bool _start(String path,
               List<String> arguments,
               String workingDirectory,
+              List<String> environment,
               Socket input,
               Socket output,
               Socket error,
               Socket exitHandler,
               _ProcessStartStatus status) native "Process_Start";
 
   InputStream get stdout() {
     if (_closed) {
       throw new ProcessException("Process closed");
     }
@@ skipping 62 matching lines @@
     _onError = callback;
   }
 
   void set onStart(void callback()) {
     _onStart = callback;
   }
 
   String _path;
   ObjectArray<String> _arguments;
   String _workingDirectory;
+  List<String> _environment;
   // Private methods of _Socket are used by _in, _out, and _err.
   _Socket _in;
   _Socket _out;
   _Socket _err;
   Socket _exitHandler;
   int _pid;
   bool _closed;
   bool _killed;
   bool _started;
   Function _onExit;
@@ skipping 109 matching lines @@
   void close() => _process.close();
 
   Process _process;
   Function _callback;
   StringBuffer _stdoutBuffer;
   StringBuffer _stderrBuffer;
   int _exitCode;
   bool _stdoutClosed = false;
   bool _stderrClosed = false;
 }