Support passing an environment variable map to child processes.

runtime/bin/process_impl.dart

Index: runtime/bin/process_impl.dart
diff --git a/runtime/bin/process_impl.dart b/runtime/bin/process_impl.dart
index 1ff6de99539345007a73cb90a160aaaf6da46bd0..ec63cac52eb22e8e6842ebee31e9a83822733b2a 100644
--- a/runtime/bin/process_impl.dart
+++ b/runtime/bin/process_impl.dart
@@ -68,6 +68,21 @@ class _InteractiveProcess implements Process {
       }
     }
 
+    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) {

[Søren Gjesse, 2012/04/19 12:45:55]

Maybe we should allow any type on value and just rely on tpString. E.g. numbers
makes sense.

[Søren Gjesse, 2012/04/19 12:45:55]

Check that the key does not contain illegal charcters e.g. =.

[Søren Gjesse, 2012/04/19 12:45:55]

For both key and value.toString() is there any charset restriction?

[Mads Ager (google), 2012/04/20 12:24:51]

I would like to start out requiring this to be a Map<String, String>. toString
is not guaranteed to return a string so these checks are needed anyway. We can
of course perform toString and then check the result but I think it is fair to
force the programmer to make environment-variable values strings.

[Mads Ager (google), 2012/04/20 12:24:51]

An early check for that would make sense, thanks. Added.

[Mads Ager (google), 2012/04/20 12:24:51]

Yes, at this point if you go out of ASCII range the Windows implementation will
not like that. I will add a note on that. The VM does not behave nicely in this
situation. It does not return an error when Dart_NewString() is passed invalid
utf8 data. I have filed issue 2663 on that. When that is fixed it should fail
somewhat gracefully.

+          throw new IllegalArgumentException(
+              "Environment key or value is not a string: ($key, $value)");
+        }
+        _environment.add('$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.
@@ -139,6 +154,7 @@ class _InteractiveProcess implements Process {
     bool success = _start(_path,
                           _arguments,
                           _workingDirectory,
+                          _environment,
                           _in,
                           _out,
                           _err,
@@ -192,6 +208,7 @@ class _InteractiveProcess implements Process {
   bool _start(String path,
               List<String> arguments,
               String workingDirectory,
+              List<String> environment,
               Socket input,
               Socket output,
               Socket error,
@@ -274,6 +291,7 @@ class _InteractiveProcess implements Process {
   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;