com.facebook.buck.apple.clang.VFSOverlay.java Source code

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Here is the source code for com.facebook.buck.apple.clang.VFSOverlay.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.apple.clang;

import com.facebook.buck.util.json.ObjectMappers;
import com.facebook.buck.util.types.Pair;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSortedMap;
import com.google.common.collect.Multimap;
import com.google.common.collect.MultimapBuilder;
import java.io.IOException;
import java.nio.file.Path;

/**
 * VFSOverlays are used for similar purposes to headermaps, but can be used to overlay more than
 * headers on the filesystem (such as modulemaps)
 *
 * <p>This class provides support for reading and generating clang vfs overlays. No spec is
 * available but we conform to the https://clang.llvm.org/doxygen/VirtualFileSystem_8cpp_source.html
 * writer class defined in the Clang documentation.
 */
@JsonSerialize(as = VFSOverlay.class)
public class VFSOverlay {

    @SuppressWarnings("PMD.UnusedPrivateField")
    @JsonProperty
    private final int version = 0;

    @SuppressWarnings("PMD.UnusedPrivateField")
    @JsonProperty("case-sensitive")
    private final boolean case_sensitive = false;

    @JsonProperty("roots")
    private ImmutableList<VirtualDirectory> computeRoots() {
        Multimap<Path, Pair<Path, Path>> byParent = MultimapBuilder.hashKeys().hashSetValues().build();
        overlays.forEach((virtual, real) -> {
            byParent.put(virtual.getParent(), new Pair<>(virtual.getFileName(), real));
        });
        return byParent.asMap().entrySet().stream()
                .map(e -> new VirtualDirectory(e.getKey(),
                        e.getValue().stream().map(x -> new VirtualFile(x.getFirst(), x.getSecond()))
                                .collect(ImmutableList.toImmutableList())))
                .collect(ImmutableList.toImmutableList());
    }

    private final ImmutableSortedMap<Path, Path> overlays;

    public VFSOverlay(ImmutableSortedMap<Path, Path> overlays) {
        this.overlays = overlays;
    }

    public String render() throws IOException {
        return ObjectMappers.WRITER.withDefaultPrettyPrinter().writeValueAsString(this);
    }

    @JsonSerialize(as = VirtualDirectory.class)
    private class VirtualDirectory {

        @SuppressWarnings("PMD.UnusedPrivateField")
        @JsonProperty
        private final String type = "directory";

        @JsonProperty
        private final Path name;

        @JsonProperty("contents")
        private final ImmutableList<VirtualFile> fileList;

        public VirtualDirectory(Path root, ImmutableList<VirtualFile> fileList) {
            this.name = root;
            this.fileList = fileList;
        }
    }

    @JsonSerialize(as = VirtualFile.class)
    private class VirtualFile {
        @SuppressWarnings("PMD.UnusedPrivateField")
        @JsonProperty
        private final String type = "file";

        @JsonProperty
        private final Path name;

        @JsonProperty("external-contents")
        private final Path realPath;

        public VirtualFile(Path name, Path realPath) {
            Preconditions
                    .checkState(realPath.isAbsolute(),
                            "Attempting to make vfsoverlay with non-absolute path '%s' for "
                                    + "external contents field. Only absolute paths are currently supported.",
                            realPath);
            this.name = name;
            this.realPath = realPath;
        }
    }
}