org.prebake.os.RealOsProcess.java Source code

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Here is the source code for org.prebake.os.RealOsProcess.java

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// Copyright 2010, Mike Samuel
//
// 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 org.prebake.os;

import java.io.File;
import java.io.IOException;
import java.nio.file.FileSystems;
import java.nio.file.Path;
import java.util.Map;

import javax.annotation.Nullable;

import com.google.common.collect.ImmutableMap;

/**
 * A process backed by a real {@code ProcessBuilder}
 *
 * @author Mike Samuel <mikesamuel@gmail.com>
 */
final class RealOsProcess extends OsProcess {
    private ProcessBuilder pb;

    RealOsProcess(OperatingSystem os, Path cwd, String cmd, String... argv) {
        super(os, cwd, cmd, argv);
    }

    @Override
    protected void setWorkdirAndCommand(Path cwd, String cmd, String... argv) {
        pb = new ProcessBuilder();
        int argc = argv.length;
        String[] combined = new String[argc + 1];
        combined[0] = cmd;
        System.arraycopy(argv, 0, combined, 1, argc);
        pb.command(combined);
        pb.directory(new File(cwd.toUri()));
    }

    @Override
    protected void combineStdoutAndStderr() {
        pb.redirectErrorStream(true);
    }

    @Override
    protected void preemptivelyKill() {
        pb = null;
    }

    @Override
    protected boolean hasStartedRunning() {
        return pb == null;
    }

    @Override
    protected Process startRunning(boolean inheritOutput, boolean closeInput, @Nullable Path outFile,
            boolean truncateOutput, @Nullable Path inFile, ImmutableMap<String, String> env, boolean inheritEnv)
            throws IOException {
        ProcessBuilder pb = this.pb;
        this.pb = null;
        if (inheritOutput) {
            pb.redirectOutput(ProcessBuilder.Redirect.INHERIT);
        }
        if (outFile != null) {
            assert outFile.getFileSystem() == FileSystems.getDefault();
            pb.redirectOutput(new File(outFile.toUri()));
        }
        if (!pb.redirectErrorStream()) {
            pb.redirectError(ProcessBuilder.Redirect.INHERIT);
        }
        if (inFile != null) {
            assert inFile.getFileSystem() == FileSystems.getDefault();
            pb.redirectInput(new File(inFile.toUri()));
        }
        if (!(inheritEnv && env.isEmpty())) {
            Map<String, String> procEnv = pb.environment();
            if (!inheritEnv) {
                procEnv.clear();
            }
            procEnv.putAll(env);
        }
        Process p = pb.start();
        if (closeInput) {
            p.getInputStream().close();
        }
        return p;
    }
}