implement a forking implementation for javah

WHATSNEW

@@ -64,6 +64,9 @@ Other changes:
    magic.
    Bugzilla Report 59860
 
+ * a new implementation "forking" has been added to <javah> and is
+   used as default when running on JDK9.
+
 Changes from Ant 1.9.6 TO Ant 1.9.7
 ===================================
 

manual/Tasks/javah.html

@@ -37,12 +37,16 @@ systems are used.</p>
 with the <code>implementation</code> attribute or a nested element.  <a
 name="implementationvalues">Here are the choices of the attribute</a>:</p>
 <ul>
-  <li>default - the default compiler (kaffeh or sun) for the platform.</li>
-  <li>sun (the standard compiler of the JDK)</li>
+  <li>default - the default compiler for the platform.</li>
+  <li>sun (the standard compiler of the JDK) - default when not
+    running on Kaffee or gcj/gij or Java9.</li>
   <li>kaffeh (the native standard compiler of <a href="http://www.kaffe.org" target="_top">Kaffe</a>)</li>
   <li>gcjh (the native standard compiler
   of <a href="http://gcc.gnu.org/java/"
-  target="_top">gcj and gij</a>) <em>since Apache Ant 1.8.2</em></li>
+        target="_top">gcj and gij</a>) <em>since Apache Ant 1.8.2</em></li>
+  <li>forking - runs the javah executable via its command line
+    interface in a separate process. Default wehn running on
+    Java9. <em>since Ant 1.9.8</em></li>
 </ul>
 
 <p><b>Note:</b> if you are using this task to work on multiple files

src/main/org/apache/tools/ant/taskdefs/optional/javah/ForkingJavah.java

@@ -0,0 +1,72 @@
+/*
+ *  Licensed to the Apache Software Foundation (ASF) under one or more
+ *  contributor license agreements.  See the NOTICE file distributed with
+ *  this work for additional information regarding copyright ownership.
+ *  The ASF licenses this file to You under the Apache License, Version 2.0
+ *  (the "License"); you may not use this file except in compliance with
+ *  the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ */
+package org.apache.tools.ant.taskdefs.optional.javah;
+
+import java.io.IOException;
+
+import org.apache.tools.ant.BuildException;
+import org.apache.tools.ant.Project;
+import org.apache.tools.ant.taskdefs.Execute;
+import org.apache.tools.ant.taskdefs.LogStreamHandler;
+import org.apache.tools.ant.taskdefs.optional.Javah;
+import org.apache.tools.ant.types.Commandline;
+import org.apache.tools.ant.util.JavaEnvUtils;
+
+/**
+ * This implementation runs the javah executable in a separate process.
+ *
+ * @since Ant 1.9.8
+ */
+public class ForkingJavah implements JavahAdapter {
+
+    /**
+     * the name of this adapter for users to select
+     */
+    public static final String IMPLEMENTATION_NAME = "forking";
+
+    /**
+     * Performs the actual compilation.
+     * @param javah the calling javah task.
+     * @return true if the compilation was successful.
+     * @throws BuildException if there is an error.
+     */
+    public boolean compile(Javah javah) throws BuildException {
+        Commandline cmd = SunJavah.setupJavahCommand(javah);
+        Project project = javah.getProject();
+        String executable = JavaEnvUtils.getJdkExecutable("javah");
+        javah.log("Running " + executable, Project.MSG_VERBOSE);
+        cmd.setExecutable(executable);
+
+        //set up the args
+        String[] args = cmd.getCommandline();
+
+        try {
+            Execute exe = new Execute(new LogStreamHandler(javah,
+                    Project.MSG_INFO,
+                    Project.MSG_WARN));
+            exe.setAntRun(project);
+            exe.setWorkingDirectory(project.getBaseDir());
+            exe.setCommandline(args);
+            exe.execute();
+            return !exe.isFailure();
+        } catch (IOException exception) {
+            throw new BuildException("Error running " + executable
+                    + " -maybe it is not on the path", exception);
+        }
+    }
+}

src/main/org/apache/tools/ant/taskdefs/optional/javah/JavahAdapterFactory.java

@@ -44,6 +44,8 @@ public class JavahAdapterFactory {
             return Kaffeh.IMPLEMENTATION_NAME;
         } else if (JavaEnvUtils.isGij()) {
             return Gcjh.IMPLEMENTATION_NAME;
+        } else if (JavaEnvUtils.isAtLeastJavaVersion(JavaEnvUtils.JAVA_9)) {
+            return ForkingJavah.IMPLEMENTATION_NAME;
         }
         return SunJavah.IMPLEMENTATION_NAME;
     }
@@ -87,6 +89,10 @@ public class JavahAdapterFactory {
         } else if ((JavaEnvUtils.isGij() && choice == null)
             || Gcjh.IMPLEMENTATION_NAME.equals(choice)) {
             return new Gcjh();
+        } else if ((JavaEnvUtils.isAtLeastJavaVersion(JavaEnvUtils.JAVA_9)
+                    && choice == null)
+                   || ForkingJavah.IMPLEMENTATION_NAME.equals(choice)) {
+            return new ForkingJavah();
         } else if (SunJavah.IMPLEMENTATION_NAME.equals(choice)) {
             return new SunJavah();
         } else if (choice != null) {

src/main/org/apache/tools/ant/taskdefs/optional/javah/SunJavah.java

@@ -69,7 +69,7 @@ public class SunJavah implements JavahAdapter {
         return ej.fork(javah) == 0;
     }
 
-    private Commandline setupJavahCommand(Javah javah) {
+    static Commandline setupJavahCommand(Javah javah) {
         Commandline cmd = new Commandline();
 
         if (javah.getDestdir() != null) {

src/tests/antunit/taskdefs/optional/javah-test.xml

@@ -110,4 +110,26 @@ public class Foo {
     <javah-fileset/>
     <au:assertFileExists file="${output}/org_example_Foo.h"/>
   </target>
+
+  <target name="testSimpleCompileSun" depends="-setupForRealJavahTests"
+          if="sunjavah.present">
+    <javah-single implementation="sun"/>
+    <au:assertFileExists file="${output}/org_example_Foo.h"/>
+  </target>
+
+  <target name="testCompileUsingFilesetSun" depends="-setupForRealJavahTests"
+          if="sunjavah.present">
+    <javah-fileset implementation="sun"/>
+    <au:assertFileExists file="${output}/org_example_Foo.h"/>
+  </target>
+
+  <target name="testSimpleCompileForking" depends="-setupForRealJavahTests">
+    <javah-single implementation="forking"/>
+    <au:assertFileExists file="${output}/org_example_Foo.h"/>
+  </target>
+
+  <target name="testCompileUsingFilesetForking" depends="-setupForRealJavahTests">
+    <javah-fileset implementation="forking"/>
+    <au:assertFileExists file="${output}/org_example_Foo.h"/>
+  </target>
 </project>