NativeFileSupport.java

package gw.util.filewatcher;

import gw.config.CommonServices;
import gw.util.Shell;

import java.io.File;
import java.net.URL;

public class NativeFileSupport {

  private static final String WATCHER_LIB = "watcher.dll";
  private static final String WATCHER_LIB_64 = "watcher64.dll";

  private static boolean _enabled = false;

  static {
    try {
      // native scanning only enabled on Windows.
      if(Shell.isWindows()) {
        if(!Boolean.getBoolean("disable.native.scanning")) {
          // hack borrowed from ClassRedefiner.loadJvmtiAccessLibrary() -- locates watcher.dll in gosu-lib/lib
          URL loc = Class.forName( "gw.NativeLibraryLocationMarker" ).getProtectionDomain().getCodeSource().getLocation();
          System.load( new File( loc.toURI() ).getParent() + File.separator + getLibraryName());
          _enabled = true;
        } else {
          CommonServices.getEntityAccess().getLogger().info("Native file support disabled by user.");
        }
      }
    } catch(Throwable t) {
      _enabled = false;
      CommonServices.getEntityAccess().getLogger().info("Failed to load native file support", t);
    }
  }

  private static String getLibraryName() {
    return is64BitJvm() ? WATCHER_LIB_64 : WATCHER_LIB;
  }

  private static boolean is64BitJvm() {
    String arch = System.getProperty( "sun.arch.data.model" );
    if("64".equals(arch)) {
      return true;
    } else if("32".equals(arch)) {
      return false;
    } else {
      return System.getProperty("java.vm.name").contains("64");
    }
  }

  public static final NativeFileSupport _instance = new NativeFileSupport();

  private NativeFileSupport() {
  }

  public static boolean isEnabled() {
    return _enabled;
  }

  public static void disable() {
    _enabled = false;
  }

  public static native boolean nativeFindFiles(final String path, final IFileHandler handler);
  
}