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

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Here is the source code for com.facebook.buck.android.ExtractResourcesStep.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.facebook.buck.step.ExecutionContext;
import com.facebook.buck.step.Step;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableSet;
import com.google.common.io.Files;
import com.google.common.io.InputSupplier;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.Enumeration;
import java.util.Set;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;

/**
 * A command that takes a set of JAR files and copies their resources (i.e., "non-.class files")
 * into a directory.
 * <p>
 * This is designed to produce a directory of resources that should be bundled with an APK.
 */
public class ExtractResourcesStep implements Step {

    private final ImmutableSet<String> pathsToThirdPartyJars;
    private final String extractedResourcesDir;

    public ExtractResourcesStep(Set<String> pathsToThirdPartyJars, String extractedResourcesDir) {
        this.pathsToThirdPartyJars = ImmutableSet.copyOf(pathsToThirdPartyJars);
        this.extractedResourcesDir = Preconditions.checkNotNull(extractedResourcesDir);
    }

    @Override
    public int execute(ExecutionContext context) {
        File outputDirectory = new File(extractedResourcesDir);
        for (String path : pathsToThirdPartyJars) {
            try (final JarFile jar = new JarFile(path)) {
                for (Enumeration<JarEntry> entries = jar.entries(); entries.hasMoreElements();) {
                    final JarEntry entry = entries.nextElement();
                    String name = entry.getName();

                    // No directories.
                    if (entry.isDirectory()) {
                        continue;
                    }

                    // No META-INF nonsense.
                    if (name.startsWith("META-INF/")) {
                        continue;
                    }

                    // No .class files.
                    if (name.endsWith(".class")) {
                        continue;
                    }

                    // No .java files, either.
                    if (name.endsWith(".java")) {
                        continue;
                    }

                    File outputFile = new File(outputDirectory, name);
                    Files.createParentDirs(outputFile);
                    Files.copy(new InputSupplier<InputStream>() {
                        @Override
                        public InputStream getInput() throws IOException {
                            return jar.getInputStream(entry);
                        }
                    }, outputFile);
                }
            } catch (IOException e) {
                e.printStackTrace(context.getStdErr());
                return 1;
            }
        }

        return 0;
    }

    @Override
    public String getDescription(ExecutionContext context) {
        return String.format("Extracting resources into %s from the following JARs: %s", extractedResourcesDir,
                pathsToThirdPartyJars);
    }

    @Override
    public String getShortName() {
        return "resource_extraction";
    }

}