/*
    * 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.commons.fileupload;
  
  import static java.lang.String.format;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.UnsupportedEncodingException;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  import java.util.NoSuchElementException;
  
  import javax.servlet.http.HttpServletRequest;
  
  import org.apache.commons.fileupload.MultipartStream.ItemInputStream;
  import org.apache.commons.fileupload.servlet.ServletFileUpload;
  import org.apache.commons.fileupload.servlet.ServletRequestContext;
  import org.apache.commons.fileupload.util.Closeable;
  import org.apache.commons.fileupload.util.FileItemHeadersImpl;
  import org.apache.commons.fileupload.util.LimitedInputStream;
  import org.apache.commons.fileupload.util.Streams;
  import org.apache.commons.io.IOUtils;
  
  /**
   * <p>High level API for processing file uploads.</p>
   *
   * <p>This class handles multiple files per single HTML widget, sent using
   * <code>multipart/mixed</code> encoding type, as specified by
   * <a href="http://www.ietf.org/rfc/rfc1867.txt">RFC 1867</a>.  Use {@link
   * #parseRequest(RequestContext)} to acquire a list of {@link
   * org.apache.commons.fileupload.FileItem}s associated with a given HTML
   * widget.</p>
   *
   * <p>How the data for individual parts is stored is determined by the factory
   * used to create them; a given part may be in memory, on disk, or somewhere
   * else.</p>
   */
  public abstract class FileUploadBase {
  
      // ---------------------------------------------------------- Class methods
  
      /**
       * <p>Utility method that determines whether the request contains multipart
       * content.</p>
       *
       * <p><strong>NOTE:</strong>This method will be moved to the
       * <code>ServletFileUpload</code> class after the FileUpload 1.1 release.
       * Unfortunately, since this method is static, it is not possible to
       * provide its replacement until this method is removed.</p>
       *
       * @param ctx The request context to be evaluated. Must be non-null.
       *
       * @return <code>true</code> if the request is multipart;
       *         <code>false</code> otherwise.
       */
      public static final boolean isMultipartContent(RequestContext ctx) {
          String contentType = ctx.getContentType();
          if (contentType == null) {
              return false;
          }
          if (contentType.toLowerCase(Locale.ENGLISH).startsWith(MULTIPART)) {
              return true;
          }
          return false;
      }
  
      /**
       * Utility method that determines whether the request contains multipart
       * content.
       *
       * @param req The servlet request to be evaluated. Must be non-null.
       *
       * @return <code>true</code> if the request is multipart;
       *         <code>false</code> otherwise.
       *
       * @deprecated 1.1 Use the method on <code>ServletFileUpload</code> instead.
       */
      @Deprecated
      public static boolean isMultipartContent(HttpServletRequest req) {
          return ServletFileUpload.isMultipartContent(req);
     }
 
     // ----------------------------------------------------- Manifest constants
 
     /**
      * HTTP content type header name.
      */
     public static final String CONTENT_TYPE = "Content-type";
 
     /**
      * HTTP content disposition header name.
      */
     public static final String CONTENT_DISPOSITION = "Content-disposition";
 
     /**
      * HTTP content length header name.
      */
     public static final String CONTENT_LENGTH = "Content-length";
 
     /**
      * Content-disposition value for form data.
      */
     public static final String FORM_DATA = "form-data";
 
     /**
      * Content-disposition value for file attachment.
      */
     public static final String ATTACHMENT = "attachment";
 
     /**
      * Part of HTTP content type header.
      */
     public static final String MULTIPART = "multipart/";
 
     /**
      * HTTP content type header for multipart forms.
      */
     public static final String MULTIPART_FORM_DATA = "multipart/form-data";
 
     /**
      * HTTP content type header for multiple uploads.
      */
     public static final String MULTIPART_MIXED = "multipart/mixed";
 
     /**
      * The maximum length of a single header line that will be parsed
      * (1024 bytes).
      * @deprecated This constant is no longer used. As of commons-fileupload
      *   1.2, the only applicable limit is the total size of a parts headers,
      *   {@link MultipartStream#HEADER_PART_SIZE_MAX}.
      */
     @Deprecated
     public static final int MAX_HEADER_SIZE = 1024;
 
     // ----------------------------------------------------------- Data members
 
     /**
      * The maximum size permitted for the complete request, as opposed to
      * {@link #fileSizeMax}. A value of -1 indicates no maximum.
      */
     private long sizeMax = -1;
 
     /**
      * The maximum size permitted for a single uploaded file, as opposed
      * to {@link #sizeMax}. A value of -1 indicates no maximum.
      */
     private long fileSizeMax = -1;
 
     /**
      * The content encoding to use when reading part headers.
      */
     private String headerEncoding;
 
     /**
      * The progress listener.
      */
     private ProgressListener listener;
 
     // ----------------------------------------------------- Property accessors
 
     /**
      * Returns the factory class used when creating file items.
      *
      * @return The factory class for new file items.
      */
     public abstract FileItemFactory getFileItemFactory();
 
     /**
      * Sets the factory class to use when creating file items.
      *
      * @param factory The factory class for new file items.
      */
     public abstract void setFileItemFactory(FileItemFactory factory);
 
     /**
      * Returns the maximum allowed size of a complete request, as opposed
      * to {@link #getFileSizeMax()}.
      *
      * @return The maximum allowed size, in bytes. The default value of
      *   -1 indicates, that there is no limit.
      *
      * @see #setSizeMax(long)
      *
      */
     public long getSizeMax() {
         return sizeMax;
     }
 
     /**
      * Sets the maximum allowed size of a complete request, as opposed
      * to {@link #setFileSizeMax(long)}.
      *
      * @param sizeMax The maximum allowed size, in bytes. The default value of
      *   -1 indicates, that there is no limit.
      *
      * @see #getSizeMax()
      *
      */
     public void setSizeMax(long sizeMax) {
         this.sizeMax = sizeMax;
     }
 
     /**
      * Returns the maximum allowed size of a single uploaded file,
      * as opposed to {@link #getSizeMax()}.
      *
      * @see #setFileSizeMax(long)
      * @return Maximum size of a single uploaded file.
      */
     public long getFileSizeMax() {
         return fileSizeMax;
     }
 
     /**
      * Sets the maximum allowed size of a single uploaded file,
      * as opposed to {@link #getSizeMax()}.
      *
      * @see #getFileSizeMax()
      * @param fileSizeMax Maximum size of a single uploaded file.
      */
     public void setFileSizeMax(long fileSizeMax) {
         this.fileSizeMax = fileSizeMax;
     }
 
     /**
      * Retrieves the character encoding used when reading the headers of an
      * individual part. When not specified, or <code>null</code>, the request
      * encoding is used. If that is also not specified, or <code>null</code>,
      * the platform default encoding is used.
      *
      * @return The encoding used to read part headers.
      */
     public String getHeaderEncoding() {
         return headerEncoding;
     }
 
     /**
      * Specifies the character encoding to be used when reading the headers of
      * individual part. When not specified, or <code>null</code>, the request
      * encoding is used. If that is also not specified, or <code>null</code>,
      * the platform default encoding is used.
      *
      * @param encoding The encoding used to read part headers.
      */
     public void setHeaderEncoding(String encoding) {
         headerEncoding = encoding;
     }
 
     // --------------------------------------------------------- Public methods
 
     /**
      * Processes an <a href="http://www.ietf.org/rfc/rfc1867.txt">RFC 1867</a>
      * compliant <code>multipart/form-data</code> stream.
      *
      * @param req The servlet request to be parsed.
      *
      * @return A list of <code>FileItem</code> instances parsed from the
      *         request, in the order that they were transmitted.
      *
      * @throws FileUploadException if there are problems reading/parsing
      *                             the request or storing files.
      *
      * @deprecated 1.1 Use {@link ServletFileUpload#parseRequest(HttpServletRequest)} instead.
      */
     @Deprecated
     public List<FileItem> parseRequest(HttpServletRequest req)
     throws FileUploadException {
         return parseRequest(new ServletRequestContext(req));
     }
 
     /**
      * Processes an <a href="http://www.ietf.org/rfc/rfc1867.txt">RFC 1867</a>
      * compliant <code>multipart/form-data</code> stream.
      *
      * @param ctx The context for the request to be parsed.
      *
      * @return An iterator to instances of <code>FileItemStream</code>
      *         parsed from the request, in the order that they were
      *         transmitted.
      *
      * @throws FileUploadException if there are problems reading/parsing
      *                             the request or storing files.
      * @throws IOException An I/O error occurred. This may be a network
      *   error while communicating with the client or a problem while
      *   storing the uploaded content.
      */
     public FileItemIterator getItemIterator(RequestContext ctx)
     throws FileUploadException, IOException {
         try {
             return new FileItemIteratorImpl(ctx);
         } catch (FileUploadIOException e) {
             // unwrap encapsulated SizeException
             throw (FileUploadException) e.getCause();
         }
     }
 
     /**
      * Processes an <a href="http://www.ietf.org/rfc/rfc1867.txt">RFC 1867</a>
      * compliant <code>multipart/form-data</code> stream.
      *
      * @param ctx The context for the request to be parsed.
      *
      * @return A list of <code>FileItem</code> instances parsed from the
      *         request, in the order that they were transmitted.
      *
      * @throws FileUploadException if there are problems reading/parsing
      *                             the request or storing files.
      */
     public List<FileItem> parseRequest(RequestContext ctx)
             throws FileUploadException {
         List<FileItem> items = new ArrayList<FileItem>();
         boolean successful = false;
         try {
             FileItemIterator iter = getItemIterator(ctx);
             FileItemFactory fac = getFileItemFactory();
             if (fac == null) {
                 throw new NullPointerException("No FileItemFactory has been set.");
             }
             while (iter.hasNext()) {
                 final FileItemStream item = iter.next();
                 // Don't use getName() here to prevent an InvalidFileNameException.
                 final String fileName = ((FileItemIteratorImpl.FileItemStreamImpl) item).name;
                 FileItem fileItem = fac.createItem(item.getFieldName(), item.getContentType(),
                                                    item.isFormField(), fileName);
                 items.add(fileItem);
                 try {
                     Streams.copy(item.openStream(), fileItem.getOutputStream(), true);
                 } catch (FileUploadIOException e) {
                     throw (FileUploadException) e.getCause();
                 } catch (IOException e) {
                     throw new IOFileUploadException(format("Processing of %s request failed. %s",
                                                            MULTIPART_FORM_DATA, e.getMessage()), e);
                 }
                 final FileItemHeaders fih = item.getHeaders();
                 fileItem.setHeaders(fih);
             }
             successful = true;
             return items;
         } catch (FileUploadIOException e) {
             throw (FileUploadException) e.getCause();
         } catch (IOException e) {
             throw new FileUploadException(e.getMessage(), e);
         } finally {
             if (!successful) {
                 for (FileItem fileItem : items) {
                     try {
                         fileItem.delete();
                     } catch (Exception ignored) {
                         // ignored TODO perhaps add to tracker delete failure list somehow?
                     }
                 }
             }
         }
     }
 
     /**
      * Processes an <a href="http://www.ietf.org/rfc/rfc1867.txt">RFC 1867</a>
      * compliant <code>multipart/form-data</code> stream.
      *
      * @param ctx The context for the request to be parsed.
      *
      * @return A map of <code>FileItem</code> instances parsed from the request.
      *
      * @throws FileUploadException if there are problems reading/parsing
      *                             the request or storing files.
      *
      * @since 1.3
      */
     public Map<String, List<FileItem>> parseParameterMap(RequestContext ctx)
             throws FileUploadException {
         final List<FileItem> items = parseRequest(ctx);
         final Map<String, List<FileItem>> itemsMap = new HashMap<String, List<FileItem>>(items.size());
 
         for (FileItem fileItem : items) {
             String fieldName = fileItem.getFieldName();
             List<FileItem> mappedItems = itemsMap.get(fieldName);
 
             if (mappedItems == null) {
                 mappedItems = new ArrayList<FileItem>();
                 itemsMap.put(fieldName, mappedItems);
             }
 
             mappedItems.add(fileItem);
         }
 
         return itemsMap;
     }
 
     // ------------------------------------------------------ Protected methods
 
     /**
      * Retrieves the boundary from the <code>Content-type</code> header.
      *
      * @param contentType The value of the content type header from which to
      *                    extract the boundary value.
      *
      * @return The boundary, as a byte array.
      */
     protected byte[] getBoundary(String contentType) {
         ParameterParser parser = new ParameterParser();
         parser.setLowerCaseNames(true);
         // Parameter parser can handle null input
         Map<String, String> params = parser.parse(contentType, new char[] {';', ','});
         String boundaryStr = params.get("boundary");
 
         if (boundaryStr == null) {
             return null;
         }
         byte[] boundary;
         try {
             boundary = boundaryStr.getBytes("ISO-8859-1");
         } catch (UnsupportedEncodingException e) {
             boundary = boundaryStr.getBytes(); // Intentionally falls back to default charset
         }
         return boundary;
     }
 
     /**
      * Retrieves the file name from the <code>Content-disposition</code>
      * header.
      *
      * @param headers A <code>Map</code> containing the HTTP request headers.
      *
      * @return The file name for the current <code>encapsulation</code>.
      * @deprecated 1.2.1 Use {@link #getFileName(FileItemHeaders)}.
      */
     @Deprecated
     protected String getFileName(Map<String, String> headers) {
         return getFileName(getHeader(headers, CONTENT_DISPOSITION));
     }
 
     /**
      * Retrieves the file name from the <code>Content-disposition</code>
      * header.
      *
      * @param headers The HTTP headers object.
      *
      * @return The file name for the current <code>encapsulation</code>.
      */
     protected String getFileName(FileItemHeaders headers) {
         return getFileName(headers.getHeader(CONTENT_DISPOSITION));
     }
 
     /**
      * Returns the given content-disposition headers file name.
      * @param pContentDisposition The content-disposition headers value.
      * @return The file name
      */
     private String getFileName(String pContentDisposition) {
         String fileName = null;
         if (pContentDisposition != null) {
             String cdl = pContentDisposition.toLowerCase(Locale.ENGLISH);
             if (cdl.startsWith(FORM_DATA) || cdl.startsWith(ATTACHMENT)) {
                 ParameterParser parser = new ParameterParser();
                 parser.setLowerCaseNames(true);
                 // Parameter parser can handle null input
                 Map<String, String> params = parser.parse(pContentDisposition, ';');
                 if (params.containsKey("filename")) {
                     fileName = params.get("filename");
                     if (fileName != null) {
                         fileName = fileName.trim();
                     } else {
                         // Even if there is no value, the parameter is present,
                         // so we return an empty file name rather than no file
                         // name.
                         fileName = "";
                     }
                 }
             }
         }
         return fileName;
     }
 
     /**
      * Retrieves the field name from the <code>Content-disposition</code>
      * header.
      *
      * @param headers A <code>Map</code> containing the HTTP request headers.
      *
      * @return The field name for the current <code>encapsulation</code>.
      */
     protected String getFieldName(FileItemHeaders headers) {
         return getFieldName(headers.getHeader(CONTENT_DISPOSITION));
     }
 
     /**
      * Returns the field name, which is given by the content-disposition
      * header.
      * @param pContentDisposition The content-dispositions header value.
      * @return The field jake
      */
     private String getFieldName(String pContentDisposition) {
         String fieldName = null;
         if (pContentDisposition != null
                 && pContentDisposition.toLowerCase(Locale.ENGLISH).startsWith(FORM_DATA)) {
             ParameterParser parser = new ParameterParser();
             parser.setLowerCaseNames(true);
             // Parameter parser can handle null input
             Map<String, String> params = parser.parse(pContentDisposition, ';');
             fieldName = params.get("name");
             if (fieldName != null) {
                 fieldName = fieldName.trim();
             }
         }
         return fieldName;
     }
 
     /**
      * Retrieves the field name from the <code>Content-disposition</code>
      * header.
      *
      * @param headers A <code>Map</code> containing the HTTP request headers.
      *
      * @return The field name for the current <code>encapsulation</code>.
      * @deprecated 1.2.1 Use {@link #getFieldName(FileItemHeaders)}.
      */
     @Deprecated
     protected String getFieldName(Map<String, String> headers) {
         return getFieldName(getHeader(headers, CONTENT_DISPOSITION));
     }
 
     /**
      * Creates a new {@link FileItem} instance.
      *
      * @param headers       A <code>Map</code> containing the HTTP request
      *                      headers.
      * @param isFormField   Whether or not this item is a form field, as
      *                      opposed to a file.
      *
      * @return A newly created <code>FileItem</code> instance.
      *
      * @throws FileUploadException if an error occurs.
      * @deprecated 1.2 This method is no longer used in favour of
      *   internally created instances of {@link FileItem}.
      */
     @Deprecated
     protected FileItem createItem(Map<String, String> headers,
                                   boolean isFormField)
         throws FileUploadException {
         return getFileItemFactory().createItem(getFieldName(headers),
                 getHeader(headers, CONTENT_TYPE),
                 isFormField,
                 getFileName(headers));
     }
 
     /**
      * <p> Parses the <code>header-part</code> and returns as key/value
      * pairs.
      *
      * <p> If there are multiple headers of the same names, the name
      * will map to a comma-separated list containing the values.
      *
      * @param headerPart The <code>header-part</code> of the current
      *                   <code>encapsulation</code>.
      *
      * @return A <code>Map</code> containing the parsed HTTP request headers.
      */
     protected FileItemHeaders getParsedHeaders(String headerPart) {
         final int len = headerPart.length();
         FileItemHeadersImpl headers = newFileItemHeaders();
         int start = 0;
         for (;;) {
             int end = parseEndOfLine(headerPart, start);
             if (start == end) {
                 break;
             }
             StringBuilder header = new StringBuilder(headerPart.substring(start, end));
             start = end + 2;
             while (start < len) {
                 int nonWs = start;
                 while (nonWs < len) {
                     char c = headerPart.charAt(nonWs);
                     if (c != ' '  &&  c != '\t') {
                         break;
                     }
                     ++nonWs;
                 }
                 if (nonWs == start) {
                     break;
                 }
                 // Continuation line found
                 end = parseEndOfLine(headerPart, nonWs);
                 header.append(" ").append(headerPart.substring(nonWs, end));
                 start = end + 2;
             }
             parseHeaderLine(headers, header.toString());
         }
         return headers;
     }
 
     /**
      * Creates a new instance of {@link FileItemHeaders}.
      * @return The new instance.
      */
     protected FileItemHeadersImpl newFileItemHeaders() {
         return new FileItemHeadersImpl();
     }
 
     /**
      * <p> Parses the <code>header-part</code> and returns as key/value
      * pairs.
      *
      * <p> If there are multiple headers of the same names, the name
      * will map to a comma-separated list containing the values.
      *
      * @param headerPart The <code>header-part</code> of the current
      *                   <code>encapsulation</code>.
      *
      * @return A <code>Map</code> containing the parsed HTTP request headers.
      * @deprecated 1.2.1 Use {@link #getParsedHeaders(String)}
      */
     @Deprecated
     protected Map<String, String> parseHeaders(String headerPart) {
         FileItemHeaders headers = getParsedHeaders(headerPart);
         Map<String, String> result = new HashMap<String, String>();
         for (Iterator<String> iter = headers.getHeaderNames();  iter.hasNext();) {
             String headerName = iter.next();
             Iterator<String> iter2 = headers.getHeaders(headerName);
             StringBuilder headerValue = new StringBuilder(iter2.next());
             while (iter2.hasNext()) {
                 headerValue.append(",").append(iter2.next());
             }
             result.put(headerName, headerValue.toString());
         }
         return result;
     }
 
     /**
      * Skips bytes until the end of the current line.
      * @param headerPart The headers, which are being parsed.
      * @param end Index of the last byte, which has yet been
      *   processed.
      * @return Index of the \r\n sequence, which indicates
      *   end of line.
      */
     private int parseEndOfLine(String headerPart, int end) {
         int index = end;
         for (;;) {
             int offset = headerPart.indexOf('\r', index);
             if (offset == -1  ||  offset + 1 >= headerPart.length()) {
                 throw new IllegalStateException(
                     "Expected headers to be terminated by an empty line.");
             }
             if (headerPart.charAt(offset + 1) == '\n') {
                 return offset;
             }
             index = offset + 1;
         }
     }
 
     /**
      * Reads the next header line.
      * @param headers String with all headers.
      * @param header Map where to store the current header.
      */
     private void parseHeaderLine(FileItemHeadersImpl headers, String header) {
         final int colonOffset = header.indexOf(':');
         if (colonOffset == -1) {
             // This header line is malformed, skip it.
             return;
         }
         String headerName = header.substring(0, colonOffset).trim();
         String headerValue =
             header.substring(header.indexOf(':') + 1).trim();
         headers.addHeader(headerName, headerValue);
     }
 
     /**
      * Returns the header with the specified name from the supplied map. The
      * header lookup is case-insensitive.
      *
      * @param headers A <code>Map</code> containing the HTTP request headers.
      * @param name    The name of the header to return.
      *
      * @return The value of specified header, or a comma-separated list if
      *         there were multiple headers of that name.
      * @deprecated 1.2.1 Use {@link FileItemHeaders#getHeader(String)}.
      */
     @Deprecated
     protected final String getHeader(Map<String, String> headers,
             String name) {
         return headers.get(name.toLowerCase(Locale.ENGLISH));
     }
 
     /**
      * The iterator, which is returned by
      * {@link FileUploadBase#getItemIterator(RequestContext)}.
      */
     private class FileItemIteratorImpl implements FileItemIterator {
 
         /**
          * Default implementation of {@link FileItemStream}.
          */
         class FileItemStreamImpl implements FileItemStream {
 
             /**
              * The file items content type.
              */
             private final String contentType;
 
             /**
              * The file items field name.
              */
             private final String fieldName;
 
             /**
              * The file items file name.
              */
             private final String name;
 
             /**
              * Whether the file item is a form field.
              */
             private final boolean formField;
 
             /**
              * The file items input stream.
              */
             private final InputStream stream;
 
             /**
              * Whether the file item was already opened.
              */
             private boolean opened;
 
             /**
              * The headers, if any.
              */
             private FileItemHeaders headers;
 
             /**
              * Creates a new instance.
              *
              * @param pName The items file name, or null.
              * @param pFieldName The items field name.
              * @param pContentType The items content type, or null.
              * @param pFormField Whether the item is a form field.
              * @param pContentLength The items content length, if known, or -1
              * @throws IOException Creating the file item failed.
              */
             FileItemStreamImpl(String pName, String pFieldName,
                     String pContentType, boolean pFormField,
                     long pContentLength) throws IOException {
                 name = pName;
                 fieldName = pFieldName;
                 contentType = pContentType;
                 formField = pFormField;
                 final ItemInputStream itemStream = multi.newInputStream();
                 InputStream istream = itemStream;
                 if (fileSizeMax != -1) {
                     if (pContentLength != -1
                             &&  pContentLength > fileSizeMax) {
                         FileSizeLimitExceededException e =
                             new FileSizeLimitExceededException(
                                 format("The field %s exceeds its maximum permitted size of %s bytes.",
                                        fieldName, Long.valueOf(fileSizeMax)),
                                 pContentLength, fileSizeMax);
                         e.setFileName(pName);
                         e.setFieldName(pFieldName);
                         throw new FileUploadIOException(e);
                     }
                     istream = new LimitedInputStream(istream, fileSizeMax) {
                         @Override
                         protected void raiseError(long pSizeMax, long pCount)
                                 throws IOException {
                             itemStream.close(true);
                             FileSizeLimitExceededException e =
                                 new FileSizeLimitExceededException(
                                     format("The field %s exceeds its maximum permitted size of %s bytes.",
                                            fieldName, Long.valueOf(pSizeMax)),
                                     pCount, pSizeMax);
                             e.setFieldName(fieldName);
                             e.setFileName(name);
                             throw new FileUploadIOException(e);
                         }
                     };
                 }
                 stream = istream;
             }
 
             /**
              * Returns the items content type, or null.
              *
              * @return Content type, if known, or null.
              */
             public String getContentType() {
                 return contentType;
             }
 
             /**
              * Returns the items field name.
              *
              * @return Field name.
              */
             public String getFieldName() {
                 return fieldName;
             }
 
             /**
              * Returns the items file name.
              *
              * @return File name, if known, or null.
              * @throws InvalidFileNameException The file name contains a NUL character,
              *   which might be an indicator of a security attack. If you intend to
              *   use the file name anyways, catch the exception and use
              *   InvalidFileNameException#getName().
              */
             public String getName() {
                 return Streams.checkFileName(name);
             }
 
             /**
              * Returns, whether this is a form field.
              *
              * @return True, if the item is a form field,
              *   otherwise false.
              */
             public boolean isFormField() {
                 return formField;
             }
 
             /**
              * Returns an input stream, which may be used to
              * read the items contents.
              *
              * @return Opened input stream.
              * @throws IOException An I/O error occurred.
              */
             public InputStream openStream() throws IOException {
                 if (opened) {
                     throw new IllegalStateException(
                             "The stream was already opened.");
                 }
                 if (((Closeable) stream).isClosed()) {
                     throw new FileItemStream.ItemSkippedException();
                 }
                 return stream;
             }
 
             /**
              * Closes the file item.
              *
              * @throws IOException An I/O error occurred.
              */
             void close() throws IOException {
                 stream.close();
             }
 
             /**
              * Returns the file item headers.
              *
              * @return The items header object
              */
             public FileItemHeaders getHeaders() {
                 return headers;
             }
 
             /**
              * Sets the file item headers.
              *
              * @param pHeaders The items header object
              */
             public void setHeaders(FileItemHeaders pHeaders) {
                 headers = pHeaders;
             }
 
         }
 
         /**
          * The multi part stream to process.
          */
         private final MultipartStream multi;
 
         /**
          * The notifier, which used for triggering the
          * {@link ProgressListener}.
          */
         private final MultipartStream.ProgressNotifier notifier;
 
         /**
          * The boundary, which separates the various parts.
          */
         private final byte[] boundary;
 
         /**
          * The item, which we currently process.
          */
         private FileItemStreamImpl currentItem;
 
         /**
          * The current items field name.
          */
         private String currentFieldName;
 
         /**
          * Whether we are currently skipping the preamble.
          */
         private boolean skipPreamble;
 
         /**
          * Whether the current item may still be read.
          */
         private boolean itemValid;
 
         /**
          * Whether we have seen the end of the file.
          */
         private boolean eof;
 
         /**
          * Creates a new instance.
          *
          * @param ctx The request context.
          * @throws FileUploadException An error occurred while
          *   parsing the request.
          * @throws IOException An I/O error occurred.
          */
         FileItemIteratorImpl(RequestContext ctx)
                 throws FileUploadException, IOException {
             if (ctx == null) {
                 throw new NullPointerException("ctx parameter");
             }
 
             String contentType = ctx.getContentType();
             if ((null == contentType)
                     || (!contentType.toLowerCase(Locale.ENGLISH).startsWith(MULTIPART))) {
                 throw new InvalidContentTypeException(
                         format("the request doesn't contain a %s or %s stream, content type header is %s",
                                MULTIPART_FORM_DATA, MULTIPART_MIXED, contentType));
             }
 
 
             @SuppressWarnings("deprecation") // still has to be backward compatible
             final int contentLengthInt = ctx.getContentLength();
 
             final long requestSize = UploadContext.class.isAssignableFrom(ctx.getClass())
                                      // Inline conditional is OK here CHECKSTYLE:OFF
                                      ? ((UploadContext) ctx).contentLength()
                                      : contentLengthInt;
                                      // CHECKSTYLE:ON
 
             InputStream input; // N.B. this is eventually closed in MultipartStream processing
             if (sizeMax >= 0) {
                 if (requestSize != -1 && requestSize > sizeMax) {
                     throw new SizeLimitExceededException(
                         format("the request was rejected because its size (%s) exceeds the configured maximum (%s)",
                                 Long.valueOf(requestSize), Long.valueOf(sizeMax)),
                                requestSize, sizeMax);
                 }
                 // N.B. this is eventually closed in MultipartStream processing
                 input = new LimitedInputStream(ctx.getInputStream(), sizeMax) {
                     @Override
                     protected void raiseError(long pSizeMax, long pCount)
                             throws IOException {
                         FileUploadException ex = new SizeLimitExceededException(
                         format("the request was rejected because its size (%s) exceeds the configured maximum (%s)",
                                 Long.valueOf(pCount), Long.valueOf(pSizeMax)),
                                pCount, pSizeMax);
                         throw new FileUploadIOException(ex);
                     }
                 };
             } else {
                 input = ctx.getInputStream();
             }
 
             String charEncoding = headerEncoding;
             if (charEncoding == null) {
                 charEncoding = ctx.getCharacterEncoding();
             }
 
             boundary = getBoundary(contentType);
             if (boundary == null) {
                 IOUtils.closeQuietly(input); // avoid possible resource leak
                 throw new FileUploadException("the request was rejected because no multipart boundary was found");
             }
 
             notifier = new MultipartStream.ProgressNotifier(listener, requestSize);
             try {
                 multi = new MultipartStream(input, boundary, notifier);
             } catch (IllegalArgumentException iae) {
                 IOUtils.closeQuietly(input); // avoid possible resource leak
                 throw new InvalidContentTypeException(
                         format("The boundary specified in the %s header is too long", CONTENT_TYPE), iae);
             }
             multi.setHeaderEncoding(charEncoding);
 
             skipPreamble = true;
             findNextItem();
         }
 
         /**
          * Called for finding the next item, if any.
          *
          * @return True, if an next item was found, otherwise false.
          * @throws IOException An I/O error occurred.
          */
         private boolean findNextItem() throws IOException {
             if (eof) {
                 return false;
             }
             if (currentItem != null) {
                 currentItem.close();
                 currentItem = null;
             }
             for (;;) {
                 boolean nextPart;
                 if (skipPreamble) {
                     nextPart = multi.skipPreamble();
                 } else {
                     nextPart = multi.readBoundary();
                 }
                 if (!nextPart) {
                     if (currentFieldName == null) {
                         // Outer multipart terminated -> No more data
                         eof = true;
                         return false;
                     }
                     // Inner multipart terminated -> Return to parsing the outer
                     multi.setBoundary(boundary);
                     currentFieldName = null;
                     continue;
                 }
                 FileItemHeaders headers = getParsedHeaders(multi.readHeaders());
                 if (currentFieldName == null) {
                     // We're parsing the outer multipart
                     String fieldName = getFieldName(headers);
                     if (fieldName != null) {
                         String subContentType = headers.getHeader(CONTENT_TYPE);
                         if (subContentType != null
                                 &&  subContentType.toLowerCase(Locale.ENGLISH)
                                         .startsWith(MULTIPART_MIXED)) {
                             currentFieldName = fieldName;
                             // Multiple files associated with this field name
                             byte[] subBoundary = getBoundary(subContentType);
                             multi.setBoundary(subBoundary);
                             skipPreamble = true;
                             continue;
                         }
                         String fileName = getFileName(headers);
                         currentItem = new FileItemStreamImpl(fileName,
                                 fieldName, headers.getHeader(CONTENT_TYPE),
                                 fileName == null, getContentLength(headers));
                         currentItem.setHeaders(headers);
                         notifier.noteItem();
                         itemValid = true;
                         return true;
                     }
                 } else {
                     String fileName = getFileName(headers);
                     if (fileName != null) {
                         currentItem = new FileItemStreamImpl(fileName,
                                 currentFieldName,
                                 headers.getHeader(CONTENT_TYPE),
                                 false, getContentLength(headers));
                         currentItem.setHeaders(headers);
                         notifier.noteItem();
                         itemValid = true;
                         return true;
                     }
                 }
                 multi.discardBodyData();
             }
         }
 
         private long getContentLength(FileItemHeaders pHeaders) {
             try {
                 return Long.parseLong(pHeaders.getHeader(CONTENT_LENGTH));
             } catch (Exception e) {
                 return -1;
             }
         }
 
         /**
          * Returns, whether another instance of {@link FileItemStream}
          * is available.
          *
          * @throws FileUploadException Parsing or processing the
          *   file item failed.
          * @throws IOException Reading the file item failed.
          * @return True, if one or more additional file items
          *   are available, otherwise false.
          */
         public boolean hasNext() throws FileUploadException, IOException {
             if (eof) {
                 return false;
             }
             if (itemValid) {
                 return true;
             }
             try {
                 return findNextItem();
             } catch (FileUploadIOException e) {
                 // unwrap encapsulated SizeException
                 throw (FileUploadException) e.getCause();
             }
         }
 
         /**
          * Returns the next available {@link FileItemStream}.
          *
          * @throws java.util.NoSuchElementException No more items are
          *   available. Use {@link #hasNext()} to prevent this exception.
          * @throws FileUploadException Parsing or processing the
          *   file item failed.
          * @throws IOException Reading the file item failed.
          * @return FileItemStream instance, which provides
          *   access to the next file item.
          */
         public FileItemStream next() throws FileUploadException, IOException {
             if (eof  ||  (!itemValid && !hasNext())) {
                 throw new NoSuchElementException();
             }
             itemValid = false;
             return currentItem;
         }
 
     }
 
     /**
      * This exception is thrown for hiding an inner
      * {@link FileUploadException} in an {@link IOException}.
      */
     public static class FileUploadIOException extends IOException {
 
         /**
          * The exceptions UID, for serializing an instance.
          */
         private static final long serialVersionUID = -7047616958165584154L;
 
         /**
          * The exceptions cause; we overwrite the parent
          * classes field, which is available since Java
          * 1.4 only.
          */
         private final FileUploadException cause;
 
         /**
          * Creates a <code>FileUploadIOException</code> with the
          * given cause.
          *
          * @param pCause The exceptions cause, if any, or null.
          */
         public FileUploadIOException(FileUploadException pCause) {
             // We're not doing super(pCause) cause of 1.3 compatibility.
             cause = pCause;
         }
 
         /**
          * Returns the exceptions cause.
          *
          * @return The exceptions cause, if any, or null.
          */
         @Override
         public Throwable getCause() {
             return cause;
         }
 
     }
 
     /**
      * Thrown to indicate that the request is not a multipart request.
      */
     public static class InvalidContentTypeException
             extends FileUploadException {
 
         /**
          * The exceptions UID, for serializing an instance.
          */
         private static final long serialVersionUID = -9073026332015646668L;
 
         /**
          * Constructs a <code>InvalidContentTypeException</code> with no
          * detail message.
          */
         public InvalidContentTypeException() {
             super();
         }
 
         /**
          * Constructs an <code>InvalidContentTypeException</code> with
          * the specified detail message.
          *
          * @param message The detail message.
          */
         public InvalidContentTypeException(String message) {
             super(message);
         }
 
         /**
          * Constructs an <code>InvalidContentTypeException</code> with
          * the specified detail message and cause.
          *
          * @param msg The detail message.
          * @param cause the original cause
          *
          * @since 1.3.1
          */
         public InvalidContentTypeException(String msg, Throwable cause) {
             super(msg, cause);
         }
     }
 
     /**
      * Thrown to indicate an IOException.
      */
     public static class IOFileUploadException extends FileUploadException {
 
         /**
          * The exceptions UID, for serializing an instance.
          */
         private static final long serialVersionUID = 1749796615868477269L;
 
         /**
          * The exceptions cause; we overwrite the parent
          * classes field, which is available since Java
          * 1.4 only.
          */
         private final IOException cause;
 
         /**
          * Creates a new instance with the given cause.
          *
          * @param pMsg The detail message.
          * @param pException The exceptions cause.
          */
         public IOFileUploadException(String pMsg, IOException pException) {
             super(pMsg);
             cause = pException;
         }
 
         /**
          * Returns the exceptions cause.
          *
          * @return The exceptions cause, if any, or null.
          */
         @Override
         public Throwable getCause() {
             return cause;
         }
 
     }
 
     /**
      * This exception is thrown, if a requests permitted size
      * is exceeded.
      */
     protected abstract static class SizeException extends FileUploadException {
 
         /**
          * Serial version UID, being used, if serialized.
          */
         private static final long serialVersionUID = -8776225574705254126L;
 
         /**
          * The actual size of the request.
          */
         private final long actual;
 
         /**
          * The maximum permitted size of the request.
          */
         private final long permitted;
 
         /**
          * Creates a new instance.
          *
          * @param message The detail message.
          * @param actual The actual number of bytes in the request.
          * @param permitted The requests size limit, in bytes.
          */
         protected SizeException(String message, long actual, long permitted) {
             super(message);
             this.actual = actual;
             this.permitted = permitted;
         }
 
         /**
          * Retrieves the actual size of the request.
          *
          * @return The actual size of the request.
          * @since 1.3
          */
         public long getActualSize() {
             return actual;
         }
 
         /**
          * Retrieves the permitted size of the request.
          *
          * @return The permitted size of the request.
          * @since 1.3
          */
         public long getPermittedSize() {
             return permitted;
         }
 
     }
 
     /**
      * Thrown to indicate that the request size is not specified. In other
      * words, it is thrown, if the content-length header is missing or
      * contains the value -1.
      *
      * @deprecated 1.2 As of commons-fileupload 1.2, the presence of a
      *   content-length header is no longer required.
      */
     @Deprecated
     public static class UnknownSizeException
         extends FileUploadException {
 
         /**
          * The exceptions UID, for serializing an instance.
          */
         private static final long serialVersionUID = 7062279004812015273L;
 
         /**
          * Constructs a <code>UnknownSizeException</code> with no
          * detail message.
          */
         public UnknownSizeException() {
             super();
         }
 
         /**
          * Constructs an <code>UnknownSizeException</code> with
          * the specified detail message.
          *
          * @param message The detail message.
          */
         public UnknownSizeException(String message) {
             super(message);
         }
 
     }
 
     /**
      * Thrown to indicate that the request size exceeds the configured maximum.
      */
     public static class SizeLimitExceededException
             extends SizeException {
 
         /**
          * The exceptions UID, for serializing an instance.
          */
         private static final long serialVersionUID = -2474893167098052828L;
 
         /**
          * @deprecated 1.2 Replaced by
          * {@link #SizeLimitExceededException(String, long, long)}
          */
         @Deprecated
         public SizeLimitExceededException() {
             this(null, 0, 0);
         }
 
         /**
          * @deprecated 1.2 Replaced by
          * {@link #SizeLimitExceededException(String, long, long)}
          * @param message The exceptions detail message.
          */
         @Deprecated
         public SizeLimitExceededException(String message) {
             this(message, 0, 0);
         }
 
         /**
          * Constructs a <code>SizeExceededException</code> with
          * the specified detail message, and actual and permitted sizes.
          *
          * @param message   The detail message.
          * @param actual    The actual request size.
          * @param permitted The maximum permitted request size.
          */
         public SizeLimitExceededException(String message, long actual,
                 long permitted) {
             super(message, actual, permitted);
         }
 
     }
 
     /**
      * Thrown to indicate that A files size exceeds the configured maximum.
      */
     public static class FileSizeLimitExceededException
             extends SizeException {
 
         /**
          * The exceptions UID, for serializing an instance.
          */
         private static final long serialVersionUID = 8150776562029630058L;
 
         /**
          * File name of the item, which caused the exception.
          */
         private String fileName;
 
         /**
          * Field name of the item, which caused the exception.
          */
         private String fieldName;
 
         /**
          * Constructs a <code>SizeExceededException</code> with
          * the specified detail message, and actual and permitted sizes.
          *
          * @param message   The detail message.
          * @param actual    The actual request size.
          * @param permitted The maximum permitted request size.
          */
         public FileSizeLimitExceededException(String message, long actual,
                 long permitted) {
             super(message, actual, permitted);
         }
 
         /**
          * Returns the file name of the item, which caused the
          * exception.
          *
          * @return File name, if known, or null.
          */
         public String getFileName() {
             return fileName;
         }
 
         /**
          * Sets the file name of the item, which caused the
          * exception.
          *
          * @param pFileName the file name of the item, which caused the exception.
          */
         public void setFileName(String pFileName) {
             fileName = pFileName;
         }
 
         /**
          * Returns the field name of the item, which caused the
          * exception.
          *
          * @return Field name, if known, or null.
          */
         public String getFieldName() {
             return fieldName;
         }
 
         /**
          * Sets the field name of the item, which caused the
          * exception.
          *
          * @param pFieldName the field name of the item,
          *        which caused the exception.
          */
         public void setFieldName(String pFieldName) {
             fieldName = pFieldName;
         }
 
     }
 
     /**
      * Returns the progress listener.
      *
      * @return The progress listener, if any, or null.
      */
     public ProgressListener getProgressListener() {
         return listener;
     }
 
     /**
      * Sets the progress listener.
      *
      * @param pListener The progress listener, if any. Defaults to null.
      */
     public void setProgressListener(ProgressListener pListener) {
         listener = pListener;
     }
 
 }