com.google.devtools.build.lib.actions.CommandLine.java Source code

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Here is the source code for com.google.devtools.build.lib.actions.CommandLine.java

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// Copyright 2014 The Bazel Authors. All rights reserved.
//
// 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.google.devtools.build.lib.actions;

import com.google.common.base.Joiner;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import com.google.devtools.build.lib.actions.Artifact.ArtifactExpander;
import com.google.devtools.build.lib.collect.CollectionUtils;
import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec;
import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec.VisibleForSerialization;
import com.google.devtools.build.lib.util.Fingerprint;

/** A representation of a list of arguments. */
public abstract class CommandLine {
    @AutoCodec
    @VisibleForSerialization
    static class EmptyCommandLine extends CommandLine {
        @Override
        public Iterable<String> arguments() throws CommandLineExpansionException {
            return ImmutableList.of();
        }
    }

    public static final CommandLine EMPTY = new EmptyCommandLine();

    /** Returns the command line. */
    public abstract Iterable<String> arguments() throws CommandLineExpansionException;

    /**
     * Returns the evaluated command line with enclosed artifacts expanded by {@code artifactExpander}
     * at execution time.
     *
     * <p>By default, this method just delegates to {@link #arguments()}, without performing any
     * artifact expansion. Subclasses should override this method if they contain TreeArtifacts and
     * need to expand them for proper argument evaluation.
     */
    public Iterable<String> arguments(ArtifactExpander artifactExpander) throws CommandLineExpansionException {
        return arguments();
    }

    public void addToFingerprint(ActionKeyContext actionKeyContext, Fingerprint fingerprint)
            throws CommandLineExpansionException {
        for (String s : arguments()) {
            fingerprint.addString(s);
        }
    }

    @AutoCodec
    @VisibleForSerialization
    static class SimpleCommandLine extends CommandLine {
        private Iterable<String> args;

        SimpleCommandLine(Iterable<String> args) {
            this.args = args;
        }

        @Override
        public Iterable<String> arguments() throws CommandLineExpansionException {
            return args;
        }
    }

    /** Returns a {@link CommandLine} backed by a copy of the given list of arguments. */
    public static CommandLine of(Iterable<String> arguments) {
        final Iterable<String> immutableArguments = CollectionUtils.makeImmutable(arguments);
        return new SimpleCommandLine(immutableArguments);
    }

    @AutoCodec
    @VisibleForSerialization
    static class PrefixedCommandLine extends CommandLine {
        private ImmutableList<String> executableArgs;
        private CommandLine commandLine;

        @VisibleForSerialization
        PrefixedCommandLine(ImmutableList<String> executableArgs, CommandLine commandLine) {
            this.executableArgs = executableArgs;
            this.commandLine = commandLine;
        }

        @Override
        public Iterable<String> arguments() throws CommandLineExpansionException {
            return Iterables.concat(executableArgs, commandLine.arguments());
        }

        @Override
        public Iterable<String> arguments(ArtifactExpander artifactExpander) throws CommandLineExpansionException {
            return Iterables.concat(executableArgs, commandLine.arguments(artifactExpander));
        }
    }

    /**
     * Returns a {@link CommandLine} that is constructed by prepending the {@code executableArgs} to
     * {@code commandLine}.
     */
    public static CommandLine concat(final ImmutableList<String> executableArgs, final CommandLine commandLine) {
        if (executableArgs.isEmpty()) {
            return commandLine;
        }
        return new PrefixedCommandLine(executableArgs, commandLine);
    }

    @AutoCodec
    @VisibleForSerialization
    static class SuffixedCommandLine extends CommandLine {
        private ImmutableList<String> executableArgs;
        private CommandLine commandLine;

        @VisibleForSerialization
        SuffixedCommandLine(ImmutableList<String> executableArgs, CommandLine commandLine) {
            this.executableArgs = executableArgs;
            this.commandLine = commandLine;
        }

        @Override
        public Iterable<String> arguments() throws CommandLineExpansionException {
            return Iterables.concat(commandLine.arguments(), executableArgs);
        }

        @Override
        public Iterable<String> arguments(ArtifactExpander artifactExpander) throws CommandLineExpansionException {
            return Iterables.concat(commandLine.arguments(artifactExpander), executableArgs);
        }
    }

    /**
     * Returns a {@link CommandLine} that is constructed by appending the {@code args} to {@code
     * commandLine}.
     */
    public static CommandLine concat(final CommandLine commandLine, final ImmutableList<String> args) {
        if (args.isEmpty()) {
            return commandLine;
        }
        return new SuffixedCommandLine(args, commandLine);
    }

    /**
     * This helps when debugging Blaze code that uses {@link CommandLine}s, as you can see their
     * content directly in the variable inspector.
     */
    @Override
    public String toString() {
        try {
            return Joiner.on(' ').join(arguments());
        } catch (CommandLineExpansionException e) {
            return "Error in expanding command line";
        }
    }
}