com.facebook.buck.cxx.CxxPrepareForLinkStep.java Source code

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Here is the source code for com.facebook.buck.cxx.CxxPrepareForLinkStep.java

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/*
 * Copyright 2014-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.cxx;

import com.facebook.buck.jvm.java.Javac;
import com.facebook.buck.log.Logger;
import com.facebook.buck.rules.SourcePathResolver;
import com.facebook.buck.rules.args.Arg;
import com.facebook.buck.rules.args.FileListableLinkerInputArg;
import com.facebook.buck.rules.args.StringArg;
import com.facebook.buck.step.CompositeStep;
import com.facebook.buck.step.ExecutionContext;
import com.facebook.buck.step.Step;
import com.facebook.buck.util.MoreCollectors;
import com.google.common.collect.ImmutableList;

import java.nio.file.Path;
import java.util.List;
import java.util.Optional;

/**
 * Prepares argfile for the CxxLinkStep, so all arguments to the linker will be stored in a
 * single file. CxxLinkStep then would pass it to the linker via @path/to/the.argsfile command.
 * This allows us to break the constraints that command line sets for the maximum length of
 * the commands.
 */
public class CxxPrepareForLinkStep extends CompositeStep {

    private static final Logger LOG = Logger.get(CxxPrepareForLinkStep.class);

    public static CxxPrepareForLinkStep create(Path argFilePath, Path fileListPath,
            Iterable<Arg> linkerArgsToSupportFileList, Path output, ImmutableList<Arg> args, Linker linker,
            Path currentCellPath, SourcePathResolver resolver) {

        ImmutableList<Arg> allArgs = new ImmutableList.Builder<Arg>()
                .addAll(StringArg.from(linker.outputArgs(output.toString()))).addAll(args)
                .addAll(linkerArgsToSupportFileList).build();

        boolean hasLinkArgsToSupportFileList = linkerArgsToSupportFileList.iterator().hasNext();

        LOG.debug("Link command (pwd=%s): %s %s", currentCellPath.toString(),
                String.join("", linker.getCommandPrefix(resolver)),
                String.join(" ", CxxWriteArgsToFileStep.stringify(allArgs, currentCellPath)));

        CxxWriteArgsToFileStep createArgFileStep = new CxxWriteArgsToFileStep(argFilePath,
                hasLinkArgsToSupportFileList
                        ? allArgs.stream().filter(input -> !(input instanceof FileListableLinkerInputArg)).collect(
                                MoreCollectors.toImmutableList())
                        : allArgs,
                Optional.of(Javac.ARGFILES_ESCAPER), currentCellPath);

        if (!hasLinkArgsToSupportFileList) {
            LOG.verbose("linkerArgsToSupportFileList is empty, filelist feature is not supported");
            return new CxxPrepareForLinkStep(ImmutableList.of(createArgFileStep));
        }

        CxxWriteArgsToFileStep createFileListStep = new CxxWriteArgsToFileStep(fileListPath,
                allArgs.stream().filter(input -> input instanceof FileListableLinkerInputArg)
                        .collect(MoreCollectors.toImmutableList()),
                Optional.empty(), currentCellPath);

        return new CxxPrepareForLinkStep(ImmutableList.of(createArgFileStep, createFileListStep));
    }

    private CxxPrepareForLinkStep(List<? extends Step> commands) {
        super(commands);
    }

    @Override
    public String getShortName() {
        return "cxx prepare for link step";
    }

    @Override
    public String getDescription(ExecutionContext context) {
        return "prepares arg file that will be passed to the linker";
    }
}