build-system/gradle-core/src/main/java/com/android/build/gradle/internal/transforms/JarMergingTransform.java

/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * 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.android.build.gradle.internal.transforms;

import static com.android.utils.FileUtils.deleteIfExists;
import static com.google.common.base.Preconditions.checkNotNull;

import com.android.annotations.NonNull;
import com.android.build.api.transform.DirectoryInput;
import com.android.build.api.transform.Format;
import com.android.build.api.transform.JarInput;
import com.android.build.api.transform.QualifiedContent.ContentType;
import com.android.build.api.transform.QualifiedContent.Scope;
import com.android.build.api.transform.Transform;
import com.android.build.api.transform.TransformException;
import com.android.build.api.transform.TransformInput;
import com.android.build.api.transform.TransformInvocation;
import com.android.build.api.transform.TransformOutputProvider;
import com.android.build.gradle.internal.pipeline.TransformManager;
import com.android.builder.packaging.JarMerger;
import com.android.builder.packaging.ZipEntryFilter;
import com.android.utils.FileUtils;
import com.google.common.collect.ImmutableSet;
import java.io.File;
import java.io.IOException;
import java.util.Set;

/**
 * A transform that merges all the incoming inputs (folders and jars) into a single jar in a
 * single combined output.
 *
 * This only packages the class files. It ignores other files.
 */
public class JarMergingTransform extends Transform {

    @NonNull
    private final ImmutableSet<Scope> scopes;

    public JarMergingTransform(@NonNull Set<Scope> scopes) {
        this.scopes = ImmutableSet.copyOf(scopes);
    }

    @NonNull
    @Override
    public String getName() {
        return "jarMerging";
    }

    @NonNull
    @Override
    public Set<ContentType> getInputTypes() {
        return TransformManager.CONTENT_CLASS;
    }

    @NonNull
    @Override
    public Set<Scope> getScopes() {
        return scopes;
    }

    @Override
    public boolean isIncremental() {
        return false;
    }

    @Override
    public void transform(@NonNull TransformInvocation invocation) throws TransformException,
            IOException {
        TransformOutputProvider outputProvider = invocation.getOutputProvider();
        checkNotNull(outputProvider, "Missing output object for transform " + getName());

        // all the output will be the same since the transform type is COMBINED.
        // and format is SINGLE_JAR so output is a jar
        File jarFile =
                outputProvider.getContentLocation(
                        "combined_classes", getOutputTypes(), getScopes(), Format.JAR);
        FileUtils.mkdirs(jarFile.getParentFile());
        deleteIfExists(jarFile);

        try (JarMerger jarMerger = new JarMerger(jarFile.toPath(), ZipEntryFilter.CLASSES_ONLY)) {
            for (TransformInput input : invocation.getInputs()) {
                for (JarInput jarInput : input.getJarInputs()) {
                    jarMerger.addJar(jarInput.getFile().toPath());
                }

                for (DirectoryInput directoryInput : input.getDirectoryInputs()) {
                    jarMerger.addDirectory(directoryInput.getFile().toPath());
                }
            }
        } catch (IOException e) {
            throw new TransformException(e);
        }
    }
}