com.facebook.buck.android.ClassNodeListSupplier.java Source code

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Here is the source code for com.facebook.buck.android.ClassNodeListSupplier.java

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/*
 * Copyright 2012-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.android;

import com.google.common.base.Supplier;
import com.google.common.base.Suppliers;
import com.google.common.base.Throwables;
import com.google.common.collect.ImmutableList;

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

import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Path;
import java.util.Collections;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

/**
 * This Supplier returns a list of all the ClassNode objects in a set of jar files.
 */
class ClassNodeListSupplier implements Supplier<ImmutableList<ClassNode>> {

    private final Iterable<Path> jarPaths;

    private ClassNodeListSupplier(Iterable<Path> jarPaths) {
        this.jarPaths = jarPaths;
    }

    public static Supplier<ImmutableList<ClassNode>> createMemoized(Iterable<Path> jarPaths) {
        return Suppliers.memoize(new ClassNodeListSupplier(jarPaths));
    }

    @Override
    public ImmutableList<ClassNode> get() {
        return loadAllClassNodes();
    }

    private ImmutableList<ClassNode> loadAllClassNodes() {
        ImmutableList.Builder<ClassNode> builder = ImmutableList.builder();

        for (Path jarPath : jarPaths) {
            try (JarFile jarFile = new JarFile(jarPath.toFile())) {
                loadClassNodes(jarFile, builder);
            } catch (IOException e) {
                throw Throwables.propagate(e);
            }
        }

        return builder.build();
    }

    private void loadClassNodes(JarFile jarFile, ImmutableList.Builder<ClassNode> builder) throws IOException {
        for (JarEntry entry : Collections.list(jarFile.entries())) {
            String name = entry.getName();
            if (entry.isDirectory() || (name == null) || !name.endsWith(".class")) {
                continue;
            }

            ClassNode node = new ClassNode();
            try (InputStream stream = jarFile.getInputStream(entry)) {
                ClassReader reader = new ClassReader(stream);
                reader.accept(node, ClassReader.SKIP_FRAMES | ClassReader.SKIP_DEBUG);
            }
            builder.add(node);
        }
    }
}