net.xeoh.plugins.base.impl.classpath.loader.FileLoader Maven / Gradle / Ivy

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/*
 * InternalClasspathLoader.java
 * 
 * Copyright (c) 2009, Ralf Biedert All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, are
 * permitted provided that the following conditions are met:
 * 
 * Redistributions of source code must retain the above copyright notice, this list of
 * conditions and the following disclaimer. Redistributions in binary form must reproduce the
 * above copyright notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * 
 * Neither the name of the author nor the names of its contributors may be used to endorse or
 * promote products derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
 * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 */
package net.xeoh.plugins.base.impl.classpath.loader;

import java.io.File;
import java.net.URI;
import java.net.URL;
import java.util.Collection;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import net.xeoh.plugins.base.Plugin;
import net.xeoh.plugins.base.impl.PluginManagerImpl;
import net.xeoh.plugins.base.impl.classpath.ClassPathManager;
import net.xeoh.plugins.base.impl.classpath.locator.AbstractClassPathLocation;
import net.xeoh.plugins.base.impl.classpath.locator.ClassPathLocator;
import net.xeoh.plugins.base.impl.classpath.locator.locations.JARClasspathLocation;
import net.xeoh.plugins.base.options.AddPluginsFromOption;

/**
 * @author rb
 *
 */
public class FileLoader extends AbstractLoader {
  private final static Logger LOGGER = LoggerFactory.getLogger(FileLoader.class);

  /**
   * @param pluginManager
   */
  public FileLoader(PluginManagerImpl pluginManager) {
    super(pluginManager);
  }

  @Override
  public boolean handlesURI(URI uri) {
    return uri != null && "file".equals(uri.getScheme());
  }

  @Override
  public void loadFrom(URI url, AddPluginsFromOption[] options) {
    // If not caught by the previous handler, handle files normally.
    if (url.getScheme().equals("file")) {
      // Now load from the given file ...
      LOGGER.debug("More specifically, trying to add from {}", url);
      try {
        File root = toFile(url.toURL());

        // ... if it exists ...
        if (root == null || !root.exists()) {
          this.logger.warning("Supplied path does not exist. Unable to add plugins from there.");
          return;
        }

        // Here we go
        locateAllPluginsAt(root);
      }
      catch (Exception e) {
        LOGGER.error("could not load plugins: {}", e.getMessage());
      }
    }
  }

  /**
   * + * Ensures the given path string starts with exactly four leading slashes. +
   */
  private static String ensureUNCPath(String path) {
    int len = path.length();
    StringBuilder result = new StringBuilder(len);
    for (int i = 0; i < 4; i++) {
      // if we have hit the first non-slash character, add another leading slash
      if (i >= len || result.length() > 0 || path.charAt(i) != '/') {
        result.append('/');
      }
    }
    result.append(path);
    return result.toString();
  }

  /**
   * + * Returns the URL as a local file, or null if the given URL does not represent a + * local file. + * + * @param url The url to
   * return the file for + * @return The local file corresponding to the given url, or null +
   */
  private static File toFile(URL url) {

    if (!"file".equalsIgnoreCase(url.getProtocol())) {
      return null;
      // assume all illegal characters have been properly encoded, so use URI class to unencode
    }

    String externalForm = url.toExternalForm();
    String pathString = externalForm.substring(5);

    try {
      if (pathString.indexOf('/') == 0) {
        if (pathString.indexOf("//") == 0) {
          externalForm = "file:" + ensureUNCPath(pathString); //$NON-NLS-1$
        }
        return new File(new URI(externalForm));
      }
      if (pathString.indexOf(':') == 1) {
        return new File(new URI("file:/" + pathString)); //$NON-NLS-1$
      }

      return new File(new URI(pathString).getSchemeSpecificPart());
    }
    catch (Exception e) {
      // URL contains unencoded characters
      return new File(pathString);
    }
  }

  /**
   * Given a top level directory, we locate all classpath locations and load all plugins we find.
   *
   * @param root
   *          The top level to start from.
   */
  void locateAllPluginsAt(File root) {
    final ClassPathManager manager = this.pluginManager.getClassPathManager();
    final ClassPathLocator locator = manager.getLocator();

    final Collection locations = locator.findBelow(root.toURI());
    for (AbstractClassPathLocation location : locations) {
      manager.registerLocation(location);

      Collection subclasses = null;

      // Check if it has a list of plugins
      if (location instanceof JARClasspathLocation) {
        final JARClasspathLocation jarLocation = (JARClasspathLocation) location;
        subclasses = jarLocation.getPredefinedPluginList();
      }

      // Add all found files ... if we have no predefined list
      if (subclasses == null)
        subclasses = manager.findSubclassesFor(location, Plugin.class);

      // Try to load them
      for (String string : subclasses) {
        tryToLoadClassAsPlugin(location, string);
      }
    }
  }
}