com.facebook.buck.java.abi.AbiClass.java Source code

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Here is the source code for com.facebook.buck.java.abi.AbiClass.java

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/*
 * Copyright 2014-present Facebook, Inc.
 *
 * Licensed 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 com.facebook.buck.java.abi;

import static org.junit.Assert.fail;

import org.objectweb.asm.ClassReader;
import org.objectweb.asm.tree.ClassNode;
import org.objectweb.asm.tree.FieldNode;
import org.objectweb.asm.tree.MethodNode;

import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Path;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

public class AbiClass {

    private final ClassNode classNode;

    private AbiClass(ClassNode classNode) {
        this.classNode = classNode;
    }

    public ClassNode getClassNode() {
        return classNode;
    }

    public MethodNode findMethod(String methodName) {
        for (MethodNode method : classNode.methods) {
            if (method.name.equals(methodName)) {
                return method;
            }
        }
        fail("Unable to find method with name: " + methodName);
        return null;
    }

    public FieldNode findField(String fieldName) {
        for (FieldNode field : classNode.fields) {
            if (field.name.equals(fieldName)) {
                return field;
            }
        }

        fail("Unable to find field with name: " + fieldName);
        return null;
    }

    public static AbiClass extract(Path pathToJar, String className) throws IOException {
        try (ZipFile zip = new ZipFile(pathToJar.toString())) {
            ZipEntry entry = zip.getEntry(className);
            try (InputStream entryStream = zip.getInputStream(entry)) {
                ClassReader reader = new ClassReader(entryStream);
                ClassNode classNode = new ClassNode();
                reader.accept(classNode, 0);

                return new AbiClass(classNode);
            }
        }
    }
}