com.facebook.buck.jvm.java.testutil.ClassesImpl.java Source code

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Here is the source code for com.facebook.buck.jvm.java.testutil.ClassesImpl.java

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/*
 * Copyright 2017-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.jvm.java.testutil;

import com.facebook.buck.io.MorePaths;
import com.google.common.io.ByteStreams;

import org.junit.rules.TemporaryFolder;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassVisitor;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.List;
import java.util.jar.JarOutputStream;
import java.util.stream.Collectors;
import java.util.zip.ZipEntry;

class ClassesImpl implements Classes {
    private final TemporaryFolder root;

    public ClassesImpl(TemporaryFolder root) {
        this.root = root;
    }

    @Override
    public void acceptClassVisitor(String qualifiedName, int flags, ClassVisitor cv) throws IOException {
        Path classFilePath = resolveClassFilePath(qualifiedName);

        try (InputStream stream = Files.newInputStream(classFilePath)) {
            ClassReader reader = new ClassReader(stream);

            reader.accept(cv, flags);
        }
    }

    @Override
    public void createJar(Path jarPath) throws IOException {
        try (JarOutputStream jar = new JarOutputStream(Files.newOutputStream(jarPath))) {
            List<Path> files = Files.walk(root.getRoot().toPath()).filter(path -> path.toFile().isFile())
                    .collect(Collectors.toList());

            for (Path file : files) {
                ZipEntry entry = new ZipEntry(
                        MorePaths.pathWithUnixSeparators(root.getRoot().toPath().relativize(file)));
                jar.putNextEntry(entry);
                ByteStreams.copy(Files.newInputStream(file), jar);
                jar.closeEntry();
            }
        }
    }

    private Path resolveClassFilePath(String qualifiedName) {
        return root.getRoot().toPath().resolve(qualifiedName.replace('.', File.separatorChar) + ".class");
    }
}