/*
* Copyright (c) 2014, 2016, 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 jdk.internal.module;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.module.ModuleDescriptor.Version;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import jdk.internal.org.objectweb.asm.Attribute;
import jdk.internal.org.objectweb.asm.ClassReader;
import jdk.internal.org.objectweb.asm.ClassVisitor;
import jdk.internal.org.objectweb.asm.ClassWriter;
import jdk.internal.org.objectweb.asm.Opcodes;
import static jdk.internal.module.ClassFileAttributes.*;
/**
* Utility class to extend a module-info.class with additional attributes.
*/
public final class ModuleInfoExtender {
// the input stream to read the original module-info.class
private final InputStream in;
// the packages in the Packages attribute
private Set<String> packages;
// the value of the Version attribute
private Version version;
// the value of the MainClass attribute
private String mainClass;
// the values for the TargetPlatform attribute
private String osName;
private String osArch;
private String osVersion;
// the hashes for the Hashes attribute
private ModuleHashes hashes;
private ModuleInfoExtender(InputStream in) {
this.in = in;
}
/**
* Sets the set of packages for the Packages attribute
*/
public ModuleInfoExtender packages(Set<String> packages) {
this.packages = Collections.unmodifiableSet(packages);
return this;
}
/**
* Sets the value of the Version attribute.
*/
public ModuleInfoExtender version(Version version) {
this.version = version;
return this;
}
/**
* Sets the value of the MainClass attribute.
*/
public ModuleInfoExtender mainClass(String mainClass) {
this.mainClass = mainClass;
return this;
}
/**
* Sets the values for the TargetPlatform attribute.
*/
public ModuleInfoExtender targetPlatform(String osName,
String osArch,
String osVersion) {
this.osName = osName;
this.osArch = osArch;
this.osVersion = osVersion;
return this;
}
/**
* The Hashes attribute will be emitted to the module-info with
* the hashes encapsulated in the given {@code ModuleHashes}
* object.
*/
public ModuleInfoExtender hashes(ModuleHashes hashes) {
this.hashes = hashes;
return this;
}
/**
* A ClassVisitor that supports adding class file attributes. If an
* attribute already exists then the first occurence of the attribute
* is replaced.
*/
private static class AttributeAddingClassVisitor extends ClassVisitor {
private Map<String, Attribute> attrs = new HashMap<>();
AttributeAddingClassVisitor(int api, ClassVisitor cv) {
super(api, cv);
}
void addAttribute(Attribute attr) {
attrs.put(attr.type, attr);
}
@Override
public void visitAttribute(Attribute attr) {
String name = attr.type;
Attribute replacement = attrs.get(name);
if (replacement != null) {
attr = replacement;
attrs.remove(name);
}
super.visitAttribute(attr);
}
/**
* Adds any remaining attributes that weren't replaced to the
* class file.
*/
void finish() {
attrs.values().forEach(a -> super.visitAttribute(a));
attrs.clear();
}
}
/**
* Outputs the modified module-info.class to the given output stream.
* Once this method has been called then the Extender object should
* be discarded.
*/
public void write(OutputStream out) throws IOException {
// emit to the output stream
out.write(toByteArray());
}
/**
* Returns the bytes of the modified module-info.class.
* Once this method has been called then the Extender object should
* be discarded.
*/
public byte[] toByteArray() throws IOException {
ClassWriter cw
= new ClassWriter(ClassWriter.COMPUTE_MAXS + ClassWriter.COMPUTE_FRAMES);
AttributeAddingClassVisitor cv
= new AttributeAddingClassVisitor(Opcodes.ASM5, cw);
ClassReader cr = new ClassReader(in);
if (packages != null)
cv.addAttribute(new ModulePackagesAttribute(packages));
if (version != null)
cv.addAttribute(new ModuleVersionAttribute(version));
if (mainClass != null)
cv.addAttribute(new ModuleMainClassAttribute(mainClass));
if (osName != null || osArch != null || osVersion != null)
cv.addAttribute(new ModuleTargetAttribute(osName, osArch, osVersion));
if (hashes != null)
cv.addAttribute(new ModuleHashesAttribute(hashes));
List<Attribute> attrs = new ArrayList<>();
// prototypes of attributes that should be parsed
attrs.add(new ModuleAttribute());
attrs.add(new ModulePackagesAttribute());
attrs.add(new ModuleVersionAttribute());
attrs.add(new ModuleMainClassAttribute());
attrs.add(new ModuleTargetAttribute());
attrs.add(new ModuleHashesAttribute());
cr.accept(cv, attrs.toArray(new Attribute[0]), 0);
// add any attributes that didn't replace previous attributes
cv.finish();
return cw.toByteArray();
}
/**
* Returns an {@code Extender} that may be used to add additional
* attributes to the module-info.class read from the given input
* stream.
*/
public static ModuleInfoExtender newExtender(InputStream in) {
return new ModuleInfoExtender(in);
}
}