com.facebook.buck.jvm.java.abi.FilesystemStubJarWriter.java Source code

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Here is the source code for com.facebook.buck.jvm.java.abi.FilesystemStubJarWriter.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.abi;

import com.facebook.buck.io.HashingDeterministicJarWriter;
import com.facebook.buck.io.MorePaths;
import com.facebook.buck.io.ProjectFilesystem;
import com.google.common.base.Preconditions;
import com.google.common.io.ByteSource;

import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.tree.ClassNode;

import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Path;
import java.util.jar.JarOutputStream;

/**
 * A {@link StubJarWriter} that writes to a file through {@link ProjectFilesystem}.
 */
class FilesystemStubJarWriter implements StubJarWriter {
    private final HashingDeterministicJarWriter jar;
    private boolean closed = false;

    public FilesystemStubJarWriter(ProjectFilesystem filesystem, Path outputPath) throws IOException {
        Preconditions.checkState(!filesystem.exists(outputPath), "Output file already exists: %s)", outputPath);

        if (outputPath.getParent() != null && !filesystem.exists(outputPath.getParent())) {
            filesystem.createParentDirs(outputPath);
        }

        jar = new HashingDeterministicJarWriter(new JarOutputStream(filesystem.newFileOutputStream(outputPath)));
    }

    @Override
    public void writeResource(Path relativePath, InputStream resourceContents) throws IOException {
        jar.writeEntry(MorePaths.pathWithUnixSeparators(relativePath), resourceContents);
    }

    @Override
    public void writeClass(Path relativePath, ClassNode stub) throws IOException {
        try (InputStream contents = getStubClassBytes(stub).openStream()) {
            jar.writeEntry(MorePaths.pathWithUnixSeparators(relativePath), contents);
        }
    }

    private static ByteSource getStubClassBytes(ClassNode node) {
        ClassWriter writer = new ClassWriter(0);
        node.accept(new AbiFilteringClassVisitor(writer));
        return ByteSource.wrap(writer.toByteArray());
    }

    @Override
    public void close() throws IOException {
        if (!closed) {
            jar.close();
        }
        closed = true;
    }
}