Add exitCode getter counterpart to the existing setter in dart:io.

BUG=https://code.google.com/p/dart/issues/detail?id=16217
R=sgjesse@google.com

Review URL: https://codereview.chromium.org//200233002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@33737 260f80e4-7a28-3924-810f-c04153c831b5

runtime/bin/io_natives.cc

@@ -48,6 +48,7 @@ namespace bin {
   V(Process_Wait, 5)                                                           \
   V(Process_Kill, 3)                                                           \
   V(Process_SetExitCode, 1)                                                    \
+  V(Process_GetExitCode, 0)                                                    \
   V(Process_Exit, 1)                                                           \
   V(Process_Sleep, 1)                                                          \
   V(Process_Pid, 1)                                                            \

runtime/bin/process.cc

@@ -221,6 +221,11 @@ void FUNCTION_NAME(Process_SetExitCode)(Dart_NativeArguments args) {
 }
 
 
+void FUNCTION_NAME(Process_GetExitCode)(Dart_NativeArguments args) {
+  Dart_SetReturnValue(args, Dart_NewInteger(Process::GlobalExitCode()));
+}
+
+
 void FUNCTION_NAME(Process_Sleep)(Dart_NativeArguments args) {
   int64_t milliseconds = 0;
   // Ignore result if passing invalid argument and just set exit code to 0.

runtime/bin/process_patch.dart

@@ -125,6 +125,7 @@ patch class _ProcessUtils {
   /* patch */ static void _exit(int status) native "Process_Exit";
   /* patch */ static void _setExitCode(int status)
       native "Process_SetExitCode";
+  /* patch */ static int _getExitCode() native "Process_GetExitCode";
   /* patch */ static void _sleep(int millis) native "Process_Sleep";
   /* patch */ static int _pid(Process process) native "Process_Pid";
   /* patch */ static Stream<ProcessSignal> _watchSignal(ProcessSignal signal) {

sdk/lib/_internal/lib/io_patch.dart

@@ -179,6 +179,9 @@ patch class _ProcessUtils {
   patch static void _setExitCode(int status) {
     throw new UnsupportedError("ProcessUtils._setExitCode");
   }
+  patch static int _getExitCode() {
+    throw new UnsupportedError("ProcessUtils._getExitCode");
+  }
   patch static void _sleep(int millis) {
     throw new UnsupportedError("ProcessUtils._sleep");
   }

sdk/lib/io/process.dart

@@ -9,6 +9,7 @@ part of dart.io;
 class _ProcessUtils {
   external static void _exit(int status);
   external static void _setExitCode(int status);
+  external static int _getExitCode();
   external static void _sleep(int millis);
   external static int _pid(Process process);
   external static Stream<ProcessSignal> _watchSignal(ProcessSignal signal);
@@ -49,7 +50,26 @@ void exit(int code) {
 }
 
 /**
- * Global exit code for the Dart VM.
+ * Set the global exit code for the Dart VM.
+ *
+ * The exit code is global for the Dart VM and the last assignment to
+ * exitCode from any isolate determines the exit code of the Dart VM
+ * on normal termination.
+ *
+ * Default value is `0`.
+ *
+ * See [exit] for more information on how to chose a value for the
+ * exit code.
+ */
+void set exitCode(int code) {
+  if (code is !int) {
+    throw new ArgumentError("Integer value for exit code expected");
+  }
+  _ProcessUtils._setExitCode(code);
+}
+
+/*
+ * Get the global exit code for the Dart VM.
  *
  * The exit code is global for the Dart VM and the last assignment to
  * exitCode from any isolate determines the exit code of the Dart VM
@@ -58,12 +78,7 @@ void exit(int code) {
  * See [exit] for more information on how to chose a value for the
  * exit code.
  */
-set exitCode(int code) {
-  if (code is !int) {
-    throw new ArgumentError("Integer value for exit code expected");
-  }
-  _ProcessUtils._setExitCode(code);
-}
+int get exitCode => _ProcessUtils._getExitCode();
 
 /**
  * Sleep for the duration specified in [duration].

tests/standalone/io/process_set_exit_code_script.dart

@@ -5,7 +5,13 @@
 import "dart:io";
 
 main() {
+  if (exitCode != 0) {
+    throw "Bad initial exit-code";
+  }
   stdout.write("standard out");
   stderr.write("standard error");
   exitCode = 25;
+  if (exitCode != 25) {
+    throw "Exit-code not set correctly";
+  }
 }