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A Java source code formatter that follows Google Java Style.
/*
* Copyright 2015 Google 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.google.googlejavaformat.java;
import static java.lang.Math.min;
import static java.nio.charset.StandardCharsets.UTF_8;
import static java.util.Comparator.comparing;
import com.google.common.io.ByteStreams;
import com.google.common.util.concurrent.MoreExecutors;
import com.google.googlejavaformat.FormatterDiagnostic;
import com.google.googlejavaformat.java.JavaFormatterOptions.Style;
import java.io.IOError;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.time.Duration;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorCompletionService;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
/** The main class for the Java formatter CLI. */
public final class Main {
private static final int MAX_THREADS = 20;
private static final String STDIN_FILENAME = "";
static String versionString() {
return "google-java-format: Version " + GoogleJavaFormatVersion.version();
}
private final PrintWriter outWriter;
private final PrintWriter errWriter;
private final InputStream inStream;
public Main(PrintWriter outWriter, PrintWriter errWriter, InputStream inStream) {
this.outWriter = outWriter;
this.errWriter = errWriter;
this.inStream = inStream;
}
/**
* The main method for the formatter, with some number of file names to format. We process them in
* parallel, but we must be careful; if multiple file names refer to the same file (which is hard
* to determine), we must serialize their updates.
*
* @param args the command-line arguments
*/
public static void main(String[] args) {
PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out, UTF_8));
PrintWriter err = new PrintWriter(new OutputStreamWriter(System.err, UTF_8));
int result = main(out, err, args);
System.exit(result);
}
/**
* Package-private main entry point used this CLI program and the java.util.spi.ToolProvider
* implementation in the same package as this Main class.
*/
static int main(PrintWriter out, PrintWriter err, String... args) {
try {
Main formatter = new Main(out, err, System.in);
return formatter.format(args);
} catch (UsageException e) {
err.print(e.getMessage());
// We return exit code 2 to differentiate usage issues from code formatting issues.
return 2;
} finally {
err.flush();
out.flush();
}
}
/**
* The main entry point for the formatter, with some number of file names to format. We process
* them in parallel, but we must be careful; if multiple file names refer to the same file (which
* is hard to determine), we must serialize their update.
*
* @param args the command-line arguments
*/
public int format(String... args) throws UsageException {
CommandLineOptions parameters = processArgs(args);
if (parameters.version()) {
errWriter.println(versionString());
return 0;
}
if (parameters.help()) {
throw new UsageException();
}
JavaFormatterOptions options =
JavaFormatterOptions.builder()
.style(parameters.aosp() ? Style.AOSP : Style.GOOGLE)
.formatJavadoc(parameters.formatJavadoc())
.build();
if (parameters.stdin()) {
return formatStdin(parameters, options);
} else {
return formatFiles(parameters, options);
}
}
private int formatFiles(CommandLineOptions parameters, JavaFormatterOptions options) {
int numThreads = min(MAX_THREADS, parameters.files().size());
ExecutorService executorService = Executors.newFixedThreadPool(numThreads);
ExecutorCompletionService cs =
new ExecutorCompletionService<>(executorService);
boolean allOk = true;
int files = 0;
for (String fileName : parameters.files()) {
if (!fileName.endsWith(".java")) {
errWriter.println("Skipping non-Java file: " + fileName);
continue;
}
Path path = Paths.get(fileName);
try {
String input = new String(Files.readAllBytes(path), UTF_8);
cs.submit(new FormatFileCallable(parameters, path, input, options));
files++;
} catch (IOException e) {
errWriter.println(fileName + ": could not read file: " + e.getMessage());
allOk = false;
}
}
List results = new ArrayList<>();
while (files > 0) {
try {
files--;
results.add(cs.take().get());
} catch (InterruptedException e) {
errWriter.println(e.getMessage());
allOk = false;
continue;
} catch (ExecutionException e) {
errWriter.println("error: " + e.getCause().getMessage());
e.getCause().printStackTrace(errWriter);
allOk = false;
continue;
}
}
Collections.sort(results, comparing(FormatFileCallable.Result::path));
for (FormatFileCallable.Result result : results) {
Path path = result.path();
if (result.exception() != null) {
for (FormatterDiagnostic diagnostic : result.exception().diagnostics()) {
errWriter.println(path + ":" + diagnostic);
}
allOk = false;
continue;
}
String formatted = result.output();
boolean changed = result.changed();
if (changed && parameters.setExitIfChanged()) {
allOk = false;
}
if (parameters.inPlace()) {
if (!changed) {
continue; // preserve original file
}
try {
Files.write(path, formatted.getBytes(UTF_8));
} catch (IOException e) {
errWriter.println(path + ": could not write file: " + e.getMessage());
allOk = false;
continue;
}
} else if (parameters.dryRun()) {
if (changed) {
outWriter.println(path);
}
} else {
outWriter.write(formatted);
}
}
if (!MoreExecutors.shutdownAndAwaitTermination(executorService, Duration.ofSeconds(5))) {
errWriter.println("Failed to shut down ExecutorService");
allOk = false;
}
return allOk ? 0 : 1;
}
private int formatStdin(CommandLineOptions parameters, JavaFormatterOptions options) {
String input;
try {
input = new String(ByteStreams.toByteArray(inStream), UTF_8);
} catch (IOException e) {
throw new IOError(e);
}
String stdinFilename = parameters.assumeFilename().orElse(STDIN_FILENAME);
boolean ok = true;
FormatFileCallable.Result result =
new FormatFileCallable(parameters, null, input, options).call();
if (result.exception() != null) {
for (FormatterDiagnostic diagnostic : result.exception().diagnostics()) {
errWriter.println(stdinFilename + ":" + diagnostic);
}
ok = false;
} else {
String output = result.output();
boolean changed = result.changed();
if (changed && parameters.setExitIfChanged()) {
ok = false;
}
if (parameters.dryRun()) {
if (changed) {
outWriter.println(stdinFilename);
}
} else {
outWriter.write(output);
}
}
return ok ? 0 : 1;
}
/** Parses and validates command-line flags. */
public static CommandLineOptions processArgs(String... args) throws UsageException {
CommandLineOptions parameters;
try {
parameters = CommandLineOptionsParser.parse(Arrays.asList(args));
} catch (IllegalArgumentException e) {
throw new UsageException(e.getMessage());
} catch (Throwable t) {
t.printStackTrace();
throw new UsageException(t.getMessage());
}
int filesToFormat = parameters.files().size();
if (parameters.stdin()) {
filesToFormat++;
}
if (parameters.inPlace() && parameters.files().isEmpty()) {
throw new UsageException("in-place formatting was requested but no files were provided");
}
if (parameters.isSelection() && filesToFormat != 1) {
throw new UsageException("partial formatting is only support for a single file");
}
if (parameters.offsets().size() != parameters.lengths().size()) {
throw new UsageException("-offsets and -lengths flags must be provided in matching pairs");
}
if (filesToFormat <= 0 && !parameters.version() && !parameters.help()) {
throw new UsageException("no files were provided");
}
if (parameters.stdin() && !parameters.files().isEmpty()) {
throw new UsageException("cannot format from standard input and files simultaneously");
}
if (parameters.assumeFilename().isPresent() && !parameters.stdin()) {
throw new UsageException(
"--assume-filename is only supported when formatting standard input");
}
if (parameters.dryRun() && parameters.inPlace()) {
throw new UsageException("cannot use --dry-run and --in-place at the same time");
}
return parameters;
}
}