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/*
 * Copyright Camunda Services GmbH and/or licensed to Camunda Services GmbH
 * under one or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information regarding copyright
 * ownership. Camunda licenses this file to you under the Apache License,
 * Version 2.0; 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.camunda.bpm.engine.impl.util;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.Closeable;
import java.io.File;
import java.io.FileOutputStream;
import java.io.Flushable;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.nio.charset.Charset;

import org.camunda.bpm.engine.ProcessEngineException;
import org.camunda.bpm.engine.impl.ProcessEngineLogger;


/**
 * @author Tom Baeyens
 * @author Frederik Heremans
 * @author Joram Barrez
 */
public class IoUtil {

  private static final EngineUtilLogger LOG = ProcessEngineLogger.UTIL_LOGGER;

  public static byte[] readInputStream(InputStream inputStream, String inputStreamName) {
    ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
    byte[] buffer = new byte[16*1024];
    try {
      int bytesRead = inputStream.read(buffer);
      while (bytesRead!=-1) {
        outputStream.write(buffer, 0, bytesRead);
        bytesRead = inputStream.read(buffer);
      }
    }
    catch (Exception e) {
      throw LOG.exceptionWhileReadingStream(inputStreamName, e);
    }
    return outputStream.toByteArray();
  }

  public static String readClasspathResourceAsString(String resourceName) {
    InputStream resourceAsStream = IoUtil.class.getClassLoader().getResourceAsStream(resourceName);

    if (resourceAsStream == null)
    {
      throw new ProcessEngineException("resource " + resourceName + " not found");
    }

    ByteArrayOutputStream outStream = new ByteArrayOutputStream();

    int next;
    byte[] result;
    byte[] buffer = new byte[1024];

    BufferedInputStream inputStream = null;
    try {
      inputStream = new BufferedInputStream(resourceAsStream);
      while ((next = inputStream.read(buffer)) >= 0)
      {
        outStream.write(buffer, 0, next);
      }

      result = outStream.toByteArray();
    }
    catch(Exception e) {
      throw LOG.exceptionWhileReadingFile(resourceName, e);
    }
    finally {
      IoUtil.closeSilently(inputStream);
      IoUtil.closeSilently(outStream);
    }
    return new String(result, Charset.forName("UTF-8"));
  }

  public static File getFile(String filePath) {
    URL url = IoUtil.class.getClassLoader().getResource(filePath);
    try {
      return new File(url.toURI());
    }
    catch (Exception e) {
      throw LOG.exceptionWhileGettingFile(filePath, e);
    }
  }

  public static void writeStringToFile(String content, String filePath) {
    BufferedOutputStream outputStream = null;
    try {
      outputStream = new BufferedOutputStream(new FileOutputStream(getFile(filePath)));
      outputStream.write(content.getBytes());
      outputStream.flush();
    }
    catch(Exception e) {
      throw LOG.exceptionWhileWritingToFile(filePath, e);
    }
    finally {
      IoUtil.closeSilently(outputStream);
    }
  }

  /**
   * Closes the given stream. The same as calling {@link Closeable#close()}, but
   * errors while closing are silently ignored.
   */
  public static void closeSilently(Closeable closeable) {
    try {
      if(closeable != null) {
        closeable.close();
      }
    }
    catch(IOException ignore) {
      LOG.debugCloseException(ignore);
    }
  }

  /**
   * Flushes the given object. The same as calling {@link Flushable#flush()}, but
   * errors while flushing are silently ignored.
   */
  public static void flushSilently(Flushable flushable) {
    try {
      if(flushable != null) {
        flushable.flush();
      }
    }
    catch(IOException ignore) {
      LOG.debugCloseException(ignore);
    }
  }
}