jdk/make/langtools/tools/previewfeature/SetupPreviewFeature.java
2026-03-11 07:15:25 +00:00

93 lines
4.4 KiB
Java

/*
* Copyright (c) 2026, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package previewfeature;
import com.sun.source.util.JavacTask;
import com.sun.source.util.Trees;
import java.io.StringWriter;
import java.lang.reflect.Field;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.HashSet;
import java.util.Set;
import java.util.stream.Collectors;
import javax.lang.model.element.ElementKind;
import javax.tools.ToolProvider;
/* Construct a hybrid PreviewFeature.Feature enum that includes constants both
* from the current JDK sources (so that they can be used in the javac API sources),
* and from the bootstrap JDK (so that they can be used in the bootstrap classfiles).
*
* This hybrid enum is only used for the interim javac.
*/
public class SetupPreviewFeature {
public static void main(String... args) throws Exception {
Class<?> runtimeFeature = Class.forName("jdk.internal.javac.PreviewFeature$Feature");
Set<String> constantsToAdd = new HashSet<>();
for (Field runtimeField : runtimeFeature.getDeclaredFields()) {
if (runtimeField.isEnumConstant()) {
constantsToAdd.add(runtimeField.getName());
}
}
var dummy = new StringWriter();
var compiler = ToolProvider.getSystemJavaCompiler();
var source = Path.of(args[0]);
try (var fm = compiler.getStandardFileManager(null, null, null)) {
JavacTask task =
(JavacTask) compiler.getTask(dummy, null, null, null, null, fm.getJavaFileObjects(source));
task.analyze();
var sourceFeature = task.getElements()
.getTypeElement("jdk.internal.javac.PreviewFeature.Feature");
int insertPosition = -1;
for (var el : sourceFeature.getEnclosedElements()) {
if (el.getKind() == ElementKind.ENUM_CONSTANT) {
constantsToAdd.remove(el.getSimpleName().toString());
if (insertPosition == (-1)) {
var trees = Trees.instance(task);
var elPath = trees.getPath(el);
insertPosition = (int) trees.getSourcePositions()
.getStartPosition(elPath.getCompilationUnit(),
elPath.getLeaf());
}
}
}
var target = Path.of(args[1]);
Files.createDirectories(target.getParent());
if (constantsToAdd.isEmpty()) {
Files.copy(source, target);
} else {
String sourceCode = Files.readString(source);
try (var out = Files.newBufferedWriter(target)) {
out.write(sourceCode, 0, insertPosition);
out.write(constantsToAdd.stream()
.collect(Collectors.joining(", ",
"/*compatibility constants:*/ ",
",\n")));
out.write(sourceCode, insertPosition, sourceCode.length() - insertPosition);
}
}
}
}
}