com.facebook.buck.core.files.FileTreeTransformer.java Source code

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Here is the source code for com.facebook.buck.core.files.FileTreeTransformer.java

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/*
 * Copyright 2019-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.core.files;

import com.facebook.buck.core.graph.transformation.ComputeKey;
import com.facebook.buck.core.graph.transformation.ComputeResult;
import com.facebook.buck.core.graph.transformation.GraphTransformer;
import com.facebook.buck.core.graph.transformation.TransformationEnvironment;
import com.facebook.buck.util.MoreMaps;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.ImmutableSortedSet;
import java.nio.file.Path;

/**
 * Produce a file tree of a provided folder, i.e. a list of files and dependent folders recursively
 */
public class FileTreeTransformer implements GraphTransformer<FileTreeKey, FileTree> {

    private FileTreeTransformer() {
    }

    public static FileTreeTransformer of() {
        return new FileTreeTransformer();
    }

    @Override
    public Class<FileTreeKey> getKeyClass() {
        return FileTreeKey.class;
    }

    @Override
    public FileTree transform(FileTreeKey key, TransformationEnvironment env) {

        DirectoryList currentDir = env.getDep(ImmutableDirectoryListKey.of(key.getPath()));
        ImmutableMap<FileTreeKey, FileTree> children = env.getDeps(FileTreeKey.class);

        ImmutableMap<Path, FileTree> deps;
        if (children.isEmpty()) {
            deps = ImmutableMap.of();
        } else {
            // Convert Map<FileTreeKey, FileTree> to Map<Path, FileTree>
            // Not using streams etc. for performance
            // May be instead have FileTree object to have Map<FileTreeKey, FileTree> instead of
            // Map<Path, FileTree>? The interface is less cleaner then, but we can reuse collections

            deps = MoreMaps.transformKeys(children, k -> k.getPath());
        }

        return ImmutableFileTree.of(key.getPath(), currentDir, deps);
    }

    @Override
    public ImmutableSet<FileTreeKey> discoverDeps(FileTreeKey key, TransformationEnvironment env) {
        DirectoryList currentDir = env.getDep(ImmutableDirectoryListKey.of(key.getPath()));
        ImmutableSortedSet<Path> subDirs = currentDir.getDirectories();
        if (subDirs.isEmpty()) {
            return ImmutableSet.of();
        }

        ImmutableSet.Builder<FileTreeKey> depsBuilder = ImmutableSet.builderWithExpectedSize(subDirs.size());

        for (Path path : subDirs) {
            depsBuilder.add(ImmutableFileTreeKey.of(path));
        }

        return depsBuilder.build();
    }

    @Override
    public ImmutableSet<? extends ComputeKey<? extends ComputeResult>> discoverPreliminaryDeps(FileTreeKey key) {
        return ImmutableSet.of(ImmutableDirectoryListKey.of(key.getPath()));
    }
}