/*
 * 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.disk;

import java.io.File;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileItemFactory;
import org.apache.commons.io.FileCleaningTracker;

The default FileItemFactory implementation. This implementation creates FileItem instances which keep their content either in memory, for smaller items, or in a temporary file on disk, for larger items. The size threshold, above which content will be stored on disk, is configurable, as is the directory in which temporary files will be created.
If not otherwise configured, the default configuration values are as
follows:

  
Size threshold is 10KB.
  
Repository is the system default temp directory, as returned by
      System.getProperty("java.io.tmpdir").


NOTE: Files are created in the system default temp directory with predictable names. This means that a local attacker with write access to that directory can perform a TOUTOC attack to replace any uploaded file with a file of the attackers choice. The implications of this will depend on how the uploaded file is used but could be significant. When using this implementation in an environment with local, untrusted users, setRepository(File) MUST be used to configure a repository location that is not publicly writable. In a Servlet container the location identified by the ServletContext attribute javax.servlet.context.tempdir
may be used.

Temporary files, which are created for file items, should be deleted later on. The best way to do this is using a FileCleaningTracker, which you can set on the DiskFileItemFactory. However, if you do use such a tracker, then you must consider the following: Temporary files are automatically deleted as soon as they are no longer needed. (More precisely, when the corresponding instance of File is garbage collected.) This is done by the so-called reaper thread, which is started and stopped automatically by the FileCleaningTracker when there are files to be tracked. It might make sense to terminate that thread, for example, if your web application ends. See the section on "Resource cleanup" in the users guide of commons-fileupload.
Since:
FileUpload 1.1/**
 * <p>The default {@link org.apache.commons.fileupload.FileItemFactory}
 * implementation. This implementation creates
 * {@link org.apache.commons.fileupload.FileItem} instances which keep their
 * content either in memory, for smaller items, or in a temporary file on disk,
 * for larger items. The size threshold, above which content will be stored on
 * disk, is configurable, as is the directory in which temporary files will be
 * created.</p>
 *
 * <p>If not otherwise configured, the default configuration values are as
 * follows:</p>
 * <ul>
 *   <li>Size threshold is 10KB.</li>
 *   <li>Repository is the system default temp directory, as returned by
 *       <code>System.getProperty("java.io.tmpdir")</code>.</li>
 * </ul>
 * <p>
 * <b>NOTE</b>: Files are created in the system default temp directory with
 * predictable names. This means that a local attacker with write access to that
 * directory can perform a TOUTOC attack to replace any uploaded file with a
 * file of the attackers choice. The implications of this will depend on how the
 * uploaded file is used but could be significant. When using this
 * implementation in an environment with local, untrusted users,
 * {@link #setRepository(File)} MUST be used to configure a repository location
 * that is not publicly writable. In a Servlet container the location identified
 * by the ServletContext attribute <code>javax.servlet.context.tempdir</code>
 * may be used.
 * </p>
 *
 * <p>Temporary files, which are created for file items, should be
 * deleted later on. The best way to do this is using a
 * {@link FileCleaningTracker}, which you can set on the
 * {@link DiskFileItemFactory}. However, if you do use such a tracker,
 * then you must consider the following: Temporary files are automatically
 * deleted as soon as they are no longer needed. (More precisely, when the
 * corresponding instance of {@link java.io.File} is garbage collected.)
 * This is done by the so-called reaper thread, which is started and stopped
 * automatically by the {@link FileCleaningTracker} when there are files to be
 * tracked.
 * It might make sense to terminate that thread, for example, if
 * your web application ends. See the section on "Resource cleanup"
 * in the users guide of commons-fileupload.</p>
 *
 * @since FileUpload 1.1
 */
public class DiskFileItemFactory implements FileItemFactory {

    // ----------------------------------------------------- Manifest constants

    
The default threshold above which uploads will be stored on disk.
/**
     * The default threshold above which uploads will be stored on disk.
     */
    public static final int DEFAULT_SIZE_THRESHOLD = 10240;

    // ----------------------------------------------------- Instance Variables

    
The directory in which uploaded files will be stored, if stored on disk.
/**
     * The directory in which uploaded files will be stored, if stored on disk.
     */
    private File repository;

    
The threshold above which uploads will be stored on disk.
/**
     * The threshold above which uploads will be stored on disk.
     */
    private int sizeThreshold = DEFAULT_SIZE_THRESHOLD;

    
The instance of FileCleaningTracker, which is responsible for deleting temporary files.
May be null, if tracking files is not required.
/**
     * <p>The instance of {@link FileCleaningTracker}, which is responsible
     * for deleting temporary files.</p>
     * <p>May be null, if tracking files is not required.</p>
     */
    private FileCleaningTracker fileCleaningTracker;

    
Default content charset to be used when no explicit charset
parameter is provided by the sender.
/**
     * Default content charset to be used when no explicit charset
     * parameter is provided by the sender.
     */
    private String defaultCharset = DiskFileItem.DEFAULT_CHARSET;

    // ----------------------------------------------------------- Constructors

    
Constructs an unconfigured instance of this class. The resulting factory
may be configured by calling the appropriate setter methods.
/**
     * Constructs an unconfigured instance of this class. The resulting factory
     * may be configured by calling the appropriate setter methods.
     */
    public DiskFileItemFactory() {
        this(DEFAULT_SIZE_THRESHOLD, null);
    }

    
Constructs a preconfigured instance of this class.
Params:
sizeThreshold – The threshold, in bytes, below which items will be
                     retained in memory and above which they will be
                     stored as a file.
repository –    The data repository, which is the directory in
                     which files will be created, should the item size
                     exceed the threshold./**
     * Constructs a preconfigured instance of this class.
     *
     * @param sizeThreshold The threshold, in bytes, below which items will be
     *                      retained in memory and above which they will be
     *                      stored as a file.
     * @param repository    The data repository, which is the directory in
     *                      which files will be created, should the item size
     *                      exceed the threshold.
     */
    public DiskFileItemFactory(int sizeThreshold, File repository) {
        this.sizeThreshold = sizeThreshold;
        this.repository = repository;
    }

    // ------------------------------------------------------------- Properties

    
Returns the directory used to temporarily store files that are larger
than the configured size threshold.
See Also:
setRepository(File)
Returns:
The directory in which temporary files will be located./**
     * Returns the directory used to temporarily store files that are larger
     * than the configured size threshold.
     *
     * @return The directory in which temporary files will be located.
     *
     * @see #setRepository(java.io.File)
     *
     */
    public File getRepository() {
        return repository;
    }

    
Sets the directory used to temporarily store files that are larger
than the configured size threshold.
Params:
repository – The directory in which temporary files will be located.
See Also:
getRepository()/**
     * Sets the directory used to temporarily store files that are larger
     * than the configured size threshold.
     *
     * @param repository The directory in which temporary files will be located.
     *
     * @see #getRepository()
     *
     */
    public void setRepository(File repository) {
        this.repository = repository;
    }

    
Returns the size threshold beyond which files are written directly to
disk. The default value is 10240 bytes.
See Also:
setSizeThreshold(int)
Returns:
The size threshold, in bytes./**
     * Returns the size threshold beyond which files are written directly to
     * disk. The default value is 10240 bytes.
     *
     * @return The size threshold, in bytes.
     *
     * @see #setSizeThreshold(int)
     */
    public int getSizeThreshold() {
        return sizeThreshold;
    }

    
Sets the size threshold beyond which files are written directly to disk.
Params:
sizeThreshold – The size threshold, in bytes.
See Also:
getSizeThreshold()/**
     * Sets the size threshold beyond which files are written directly to disk.
     *
     * @param sizeThreshold The size threshold, in bytes.
     *
     * @see #getSizeThreshold()
     *
     */
    public void setSizeThreshold(int sizeThreshold) {
        this.sizeThreshold = sizeThreshold;
    }

    // --------------------------------------------------------- Public Methods

    
Create a new DiskFileItem instance from the supplied parameters and the local factory configuration. 
Params:
fieldName –   The name of the form field.
contentType – The content type of the form field.
isFormField – true if this is a plain form field;
                   false otherwise.
fileName –    The name of the uploaded file, if any, as supplied
                   by the browser or other client.
Returns:
The newly created file item./**
     * Create a new {@link org.apache.commons.fileupload.disk.DiskFileItem}
     * instance from the supplied parameters and the local factory
     * configuration.
     *
     * @param fieldName   The name of the form field.
     * @param contentType The content type of the form field.
     * @param isFormField <code>true</code> if this is a plain form field;
     *                    <code>false</code> otherwise.
     * @param fileName    The name of the uploaded file, if any, as supplied
     *                    by the browser or other client.
     *
     * @return The newly created file item.
     */
    @Override
    public FileItem createItem(String fieldName, String contentType,
            boolean isFormField, String fileName) {
        DiskFileItem result = new DiskFileItem(fieldName, contentType,
                isFormField, fileName, sizeThreshold, repository);
        result.setDefaultCharset(defaultCharset);
        FileCleaningTracker tracker = getFileCleaningTracker();
        if (tracker != null) {
            tracker.track(result.getTempFile(), result);
        }
        return result;
    }

    
Returns the tracker, which is responsible for deleting temporary
files.
Returns:
An instance of FileCleaningTracker, or null (default), if temporary files aren't tracked./**
     * Returns the tracker, which is responsible for deleting temporary
     * files.
     *
     * @return An instance of {@link FileCleaningTracker}, or null
     *   (default), if temporary files aren't tracked.
     */
    public FileCleaningTracker getFileCleaningTracker() {
        return fileCleaningTracker;
    }

    
Sets the tracker, which is responsible for deleting temporary
files.
Params:
pTracker – An instance of FileCleaningTracker, which will from now on track the created files, or null (default), to disable tracking./**
     * Sets the tracker, which is responsible for deleting temporary
     * files.
     *
     * @param pTracker An instance of {@link FileCleaningTracker},
     *   which will from now on track the created files, or null
     *   (default), to disable tracking.
     */
    public void setFileCleaningTracker(FileCleaningTracker pTracker) {
        fileCleaningTracker = pTracker;
    }

    
Returns the default charset for use when no explicit charset
parameter is provided by the sender.
Returns:
the default charset/**
     * Returns the default charset for use when no explicit charset
     * parameter is provided by the sender.
     * @return the default charset
     */
    public String getDefaultCharset() {
        return defaultCharset;
    }

    
Sets the default charset for use when no explicit charset
parameter is provided by the sender.
Params:
pCharset – the default charset/**
     * Sets the default charset for use when no explicit charset
     * parameter is provided by the sender.
     * @param pCharset the default charset
     */
    public void setDefaultCharset(String pCharset) {
        defaultCharset = pCharset;
    }
}