/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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 org.apache.maven.plugins.pmd.exec;
  
  import java.io.BufferedInputStream;
  import java.io.BufferedOutputStream;
  import java.io.File;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.io.UnsupportedEncodingException;
  import java.net.URL;
  import java.net.URLClassLoader;
  import java.net.URLDecoder;
  import java.nio.charset.StandardCharsets;
  
  import org.codehaus.plexus.logging.console.ConsoleLogger;
  
  abstract class Executor {
  
      protected static String buildClasspath() {
          StringBuilder classpath = new StringBuilder();
  
          // plugin classpath needs to come first
          ClassLoader pluginClassloader = Executor.class.getClassLoader();
          buildClasspath(classpath, pluginClassloader);
  
          ClassLoader coreClassloader = ConsoleLogger.class.getClassLoader();
          buildClasspath(classpath, coreClassloader);
  
          return classpath.toString();
      }
  
      static void buildClasspath(StringBuilder classpath, ClassLoader cl) {
          if (cl instanceof URLClassLoader) {
              for (URL url : ((URLClassLoader) cl).getURLs()) {
                  if ("file".equalsIgnoreCase(url.getProtocol())) {
                      try {
                          String filename = URLDecoder.decode(url.getPath(), StandardCharsets.UTF_8.name());
                          classpath.append(new File(filename).getPath()).append(File.pathSeparatorChar);
                      } catch (UnsupportedEncodingException e) {
                          // skip as we provide the correct standard encoding
                      }
                  }
              }
          }
      }
  
      protected static class ProcessStreamHandler implements Runnable {
          private static final int BUFFER_SIZE = 8192;
  
          private final BufferedInputStream in;
          private final BufferedOutputStream out;
  
          public static void start(InputStream in, OutputStream out) {
              Thread t = new Thread(new ProcessStreamHandler(in, out));
              t.start();
          }
  
          private ProcessStreamHandler(InputStream in, OutputStream out) {
              this.in = new BufferedInputStream(in);
              this.out = new BufferedOutputStream(out);
          }
  
          @Override
          public void run() {
              byte[] buffer = new byte[BUFFER_SIZE];
              try {
                  int count = in.read(buffer);
                  while (count != -1) {
                      out.write(buffer, 0, count);
                      out.flush();
                      count = in.read(buffer);
                  }
                  out.flush();
              } catch (IOException e) {
                  e.printStackTrace();
              }
          }
      }
  }