Converted the old MacCommandLauncher to new setup. There is no need to extend ProxyCommandLauncher as it did not offer any benefit (because the 2 arg version of Runtime.exec was always called)

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@270280 13f79535-47bb-0310-9956-ffa450edef68

proposal/myrmidon/src/java/org/apache/myrmidon/framework/exec/launchers/MacCommandLauncher.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) The Apache Software Foundation. All rights reserved.
+ *
+ * This software is published under the terms of the Apache Software License
+ * version 1.1, a copy of which has been included  with this distribution in
+ * the LICENSE.txt file.
+ */
+package org.apache.myrmidon.framework.exec.launchers;
+
+import java.io.File;
+import java.io.IOException;
+import org.apache.myrmidon.api.TaskException;
+import org.apache.myrmidon.framework.exec.CommandLauncher;
+import org.apache.myrmidon.framework.exec.ExecMetaData;
+
+/**
+ * A command launcher for Mac that uses a dodgy mechanism to change working
+ * directory before launching commands. This class changes the value of the
+ * System property "user.dir" before the command is executed and then resets
+ * it after the command is executed. This can have really unhealthy side-effects
+ * if there are multiple threads in JVM and should be used with extreme caution.
+ *
+ * @author <a href="mailto:peter@apache.org">Peter Donald</a>
+ * @author <a href="mailto:thomas.haas@softwired-inc.com">Thomas Haas</a>
+ * @version $Revision$ $Date$
+ */
+public class MacCommandLauncher
+    implements CommandLauncher
+{
+    /**
+     * Execute the specified native command.
+     */
+    public Process exec( final ExecMetaData metaData )
+        throws IOException, TaskException
+    {
+        final File directory = metaData.getWorkingDirectory().getCanonicalFile();
+        if( ExecUtil.isCwd( directory ) )
+        {
+            return Runtime.getRuntime().
+                exec( metaData.getCommand(), metaData.getEnvironment() );
+        }
+
+        //WARNING: This is an ugly hack and not thread safe in the slightest way
+        //It can have really really undersirable side-effects if multiple threads
+        //are running in the JVM
+        try
+        {
+            System.setProperty( "user.dir", directory.toString() );
+            return Runtime.getRuntime().
+                exec( metaData.getCommand(), metaData.getEnvironment() );
+        }
+        finally
+        {
+            System.setProperty( "user.dir", ExecUtil.getCwd().toString() );
+        }
+    }
+}