WebKit由来のソースコード行数を調べる

Main.java

package yuji.software;

import java.io.*;
import java.nio.file.Files;
import java.nio.file.Path;
import java.time.OffsetDateTime;
import java.time.ZoneOffset;
import java.util.Optional;
import java.util.function.Predicate;
import java.util.stream.Stream;

public class Main {
    private static final OffsetDateTime EPOCH =
            OffsetDateTime.of(2013, 4, 3, 0, 0, 0, 0, ZoneOffset.UTC);

    private static final long EPOCH_TIME =
            EPOCH.toInstant().toEpochMilli() / 1000;

    static final class Result {
        private long files;
        private long lines;
        private long webkit;

        public Result add(Result r) {
            this.files += r.files;
            this.lines += r.lines;
            this.webkit += r.webkit;
            return this;
        }

        @Override
        public String toString() {
            return "files=" + files + ", lines=" + lines + ", webkit=" + webkit;
        }
    }

    private final File root;

    public Main(Path root) {
        this.root = root.toFile();
    }

    public void run() throws IOException {
        try (Stream<Path> stream = Files.walk(root.toPath())) {
            Optional<Result> result = stream
                    .filter(Files::isRegularFile)
                    .filter(p -> !p.toString().toUpperCase().contains("TEST"))
                    .filter(p -> !p.toString().contains("/.git/"))
                    .filter(Predicate.not(this::isBinary))
                    //.limit(2)
                    .map(this::parse)
                    .parallel()
                    .reduce(Result::add);

            System.out.println(result);
        }
    }

    private boolean isBinary(Path path) {
        try (InputStream stream = Files.newInputStream(path)) {
            int b;
            do {
                b = stream.read();
                if (b == 0x0) {
                    return true;
                }
            } while (b != -1);
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
        return false;
    }

    private Result parse(Path path) {
        try {
            Process process =
                    new ProcessBuilder("git", "blame", "--follow", "-w", "--line-porcelain", path.toString())
                            .directory(root)
                            .start();

            Result r = new Result();
            r.files = 1;
            try (BufferedReader reader = new BufferedReader(process.inputReader())) {
                reader.lines()
                        .filter(line -> line.startsWith("author-time "))
                        .mapToLong(line -> Long.parseLong(line.split(" ")[1]))
                        .forEach(time -> {
                            if (time <= EPOCH_TIME) {
                                r.webkit++;
                            }
                            r.lines++;
                        });
            }
            process.waitFor();

            System.err.println(path + " (" + r + ")");

            return r;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public static void main(String[] args) throws IOException {
        Path root = Path.of(args[0]);
        new Main(root).run();
    }
}