wrm.WatchMojo Maven / Gradle / Ivy

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Libsass plugin for maven
There is a newer version: 0.3.1
package wrm;

import static java.nio.file.StandardWatchEventKinds.ENTRY_CREATE;
import static java.nio.file.StandardWatchEventKinds.ENTRY_DELETE;
import static java.nio.file.StandardWatchEventKinds.ENTRY_MODIFY;
import static java.nio.file.StandardWatchEventKinds.OVERFLOW;

import java.io.IOException;
import java.nio.file.FileSystems;
import java.nio.file.FileVisitResult;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.WatchEvent;
import java.nio.file.WatchKey;
import java.nio.file.WatchService;
import java.nio.file.attribute.BasicFileAttributes;
import org.apache.commons.lang3.exception.ExceptionUtils;
import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugin.MojoFailureException;

/**
 * Watch for changes in inputPath, then compile scss files to outputPath using includePaths.
 *
 * @goal watch
 */
public class WatchMojo extends AbstractSassMojo {

  /**
   * Watch for changes in inputPath, then compile scss files to outputPath using includePaths.
   */
  public void execute() throws MojoExecutionException, MojoFailureException {
    validateConfig();
    compiler = initCompiler();

    inputPath = inputPath.replaceAll("\\\\", "/");

    getLog().debug("Input Path=" + inputPath);
    getLog().debug("Output Path=" + outputPath);

    try (WatchService watcher = FileSystems.getDefault().newWatchService()) {
      registerWatchDirectories(watcher);

      getLog().info("Watching [" + inputPath + "]...");
      try {
        long lastModified = 0;
        for (; ; ) {
          WatchKey key = watcher.take();
          for (WatchEvent event : key.pollEvents()) {
            if (event.kind() == OVERFLOW) {
              continue;
            }
            Path modifiedFile = ((Path) key.watchable()).resolve((Path) event.context());
            if (modifiedFile.toFile().lastModified() - lastModified > 1000) {
              // Ignore multiple occurrences that are too close
              // Usually caused by editors (where content is changed
              // and then file attributes are changed)
              getLog().debug(String.format(
                  "%s: %s", event.kind().name(), modifiedFile));
              try {
                compile();
              } catch (Exception e) {
                // ignore
              }
            }
            lastModified = modifiedFile.toFile().lastModified();
            break;
          }
          if (!key.reset()) {
            break;
          }
        }
      } catch (InterruptedException e) {
        getLog().warn("Watch service interrupted");
      }
    } catch (IOException e) {
      throw new MojoExecutionException(
          "Exception while watching: " + ExceptionUtils.getRootCauseMessage(e), e);
    }
  }

  /**
   * registers inputPath and includePaths in watcher.
   */
  private void registerWatchDirectories(WatchService watcher) throws IOException {
    Path root = project.getBasedir().toPath().resolve(Paths.get(inputPath));
    registerAll(root, watcher);

    if (this.includePath != null) {
      for (String inclPath : includePath.split(";")) {
        Path incl = project.getBasedir().toPath().resolve(Paths.get(inclPath));
        registerAll(incl, watcher);
      }
    }
  }

  /**
   * Register the given directory, and all its sub-directories, with the WatchService.
   */
  private void registerAll(Path start, WatchService watcher) throws IOException {
    // register directory and sub-directories
    Files.walkFileTree(start, new SimpleFileVisitor() {
      @Override
      public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs)
          throws IOException {
        dir.register(watcher, ENTRY_CREATE, ENTRY_DELETE, ENTRY_MODIFY);
        return FileVisitResult.CONTINUE;
      }
    });
  }

}