/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project 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 io.netty.handler.codec.http.multipart;

import io.netty.handler.codec.http.DefaultHttpRequest;
import io.netty.handler.codec.http.HttpConstants;
import io.netty.handler.codec.http.HttpRequest;

import java.io.IOException;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.Collections;
import java.util.IdentityHashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

Default factory giving Attribute and FileUpload according to constructor. 
According to the constructor, Attribute and FileUpload can be:

MemoryAttribute, DiskAttribute or MixedAttribute
MemoryFileUpload, DiskFileUpload or MixedFileUpload

/**
 * Default factory giving {@link Attribute} and {@link FileUpload} according to constructor.
 *
 * <p>According to the constructor, {@link Attribute} and {@link FileUpload} can be:</p>
 * <ul>
 * <li>MemoryAttribute, DiskAttribute or MixedAttribute</li>
 * <li>MemoryFileUpload, DiskFileUpload or MixedFileUpload</li>
 * </ul>
 */
public class DefaultHttpDataFactory implements HttpDataFactory {

    
Proposed default MINSIZE as 16 KB.
/**
     * Proposed default MINSIZE as 16 KB.
     */
    public static final long MINSIZE = 0x4000;
    
Proposed default MAXSIZE = -1 as UNLIMITED
/**
     * Proposed default MAXSIZE = -1 as UNLIMITED
     */
    public static final long MAXSIZE = -1;

    private final boolean useDisk;

    private final boolean checkSize;

    private long minSize;

    private long maxSize = MAXSIZE;

    private Charset charset = HttpConstants.DEFAULT_CHARSET;

    
Keep all HttpDatas until cleaning methods are called. We need to use IdentityHashMap because different requests may be equal. See DefaultHttpRequest.hashCode and DefaultHttpRequest.equals. Similarly, when removing data items, we need to check their identities because different data items may be equal. /**
     * Keep all {@link HttpData}s until cleaning methods are called.
     * We need to use {@link IdentityHashMap} because different requests may be equal.
     * See {@link DefaultHttpRequest#hashCode} and {@link DefaultHttpRequest#equals}.
     * Similarly, when removing data items, we need to check their identities because
     * different data items may be equal.
     */
    private final Map<HttpRequest, List<HttpData>> requestFileDeleteMap =
            Collections.synchronizedMap(new IdentityHashMap<HttpRequest, List<HttpData>>());

    
HttpData will be in memory if less than default size (16KB).
The type will be Mixed.
/**
     * HttpData will be in memory if less than default size (16KB).
     * The type will be Mixed.
     */
    public DefaultHttpDataFactory() {
        useDisk = false;
        checkSize = true;
        minSize = MINSIZE;
    }

    public DefaultHttpDataFactory(Charset charset) {
        this();
        this.charset = charset;
    }

    
HttpData will be always on Disk if useDisk is True, else always in Memory if False
/**
     * HttpData will be always on Disk if useDisk is True, else always in Memory if False
     */
    public DefaultHttpDataFactory(boolean useDisk) {
        this.useDisk = useDisk;
        checkSize = false;
    }

    public DefaultHttpDataFactory(boolean useDisk, Charset charset) {
        this(useDisk);
        this.charset = charset;
    }
    
HttpData will be on Disk if the size of the file is greater than minSize, else it
will be in memory. The type will be Mixed.
/**
     * HttpData will be on Disk if the size of the file is greater than minSize, else it
     * will be in memory. The type will be Mixed.
     */
    public DefaultHttpDataFactory(long minSize) {
        useDisk = false;
        checkSize = true;
        this.minSize = minSize;
    }

    public DefaultHttpDataFactory(long minSize, Charset charset) {
        this(minSize);
        this.charset = charset;
    }

    @Override
    public void setMaxLimit(long maxSize) {
        this.maxSize = maxSize;
    }

    
Returns:
the associated list of HttpData for the request/**
     * @return the associated list of {@link HttpData} for the request
     */
    private List<HttpData> getList(HttpRequest request) {
        List<HttpData> list = requestFileDeleteMap.get(request);
        if (list == null) {
            list = new ArrayList<HttpData>();
            requestFileDeleteMap.put(request, list);
        }
        return list;
    }

    @Override
    public Attribute createAttribute(HttpRequest request, String name) {
        if (useDisk) {
            Attribute attribute = new DiskAttribute(name, charset);
            attribute.setMaxSize(maxSize);
            List<HttpData> list = getList(request);
            list.add(attribute);
            return attribute;
        }
        if (checkSize) {
            Attribute attribute = new MixedAttribute(name, minSize, charset);
            attribute.setMaxSize(maxSize);
            List<HttpData> list = getList(request);
            list.add(attribute);
            return attribute;
        }
        MemoryAttribute attribute = new MemoryAttribute(name);
        attribute.setMaxSize(maxSize);
        return attribute;
    }

    @Override
    public Attribute createAttribute(HttpRequest request, String name, long definedSize) {
        if (useDisk) {
            Attribute attribute = new DiskAttribute(name, definedSize, charset);
            attribute.setMaxSize(maxSize);
            List<HttpData> list = getList(request);
            list.add(attribute);
            return attribute;
        }
        if (checkSize) {
            Attribute attribute = new MixedAttribute(name, definedSize, minSize, charset);
            attribute.setMaxSize(maxSize);
            List<HttpData> list = getList(request);
            list.add(attribute);
            return attribute;
        }
        MemoryAttribute attribute = new MemoryAttribute(name, definedSize);
        attribute.setMaxSize(maxSize);
        return attribute;
    }

    
Utility method
/**
     * Utility method
     */
    private static void checkHttpDataSize(HttpData data) {
        try {
            data.checkSize(data.length());
        } catch (IOException ignored) {
            throw new IllegalArgumentException("Attribute bigger than maxSize allowed");
        }
    }

    @Override
    public Attribute createAttribute(HttpRequest request, String name, String value) {
        if (useDisk) {
            Attribute attribute;
            try {
                attribute = new DiskAttribute(name, value, charset);
                attribute.setMaxSize(maxSize);
            } catch (IOException e) {
                // revert to Mixed mode
                attribute = new MixedAttribute(name, value, minSize, charset);
                attribute.setMaxSize(maxSize);
            }
            checkHttpDataSize(attribute);
            List<HttpData> list = getList(request);
            list.add(attribute);
            return attribute;
        }
        if (checkSize) {
            Attribute attribute = new MixedAttribute(name, value, minSize, charset);
            attribute.setMaxSize(maxSize);
            checkHttpDataSize(attribute);
            List<HttpData> list = getList(request);
            list.add(attribute);
            return attribute;
        }
        try {
            MemoryAttribute attribute = new MemoryAttribute(name, value, charset);
            attribute.setMaxSize(maxSize);
            checkHttpDataSize(attribute);
            return attribute;
        } catch (IOException e) {
            throw new IllegalArgumentException(e);
        }
    }

    @Override
    public FileUpload createFileUpload(HttpRequest request, String name, String filename,
            String contentType, String contentTransferEncoding, Charset charset,
            long size) {
        if (useDisk) {
            FileUpload fileUpload = new DiskFileUpload(name, filename, contentType,
                    contentTransferEncoding, charset, size);
            fileUpload.setMaxSize(maxSize);
            checkHttpDataSize(fileUpload);
            List<HttpData> list = getList(request);
            list.add(fileUpload);
            return fileUpload;
        }
        if (checkSize) {
            FileUpload fileUpload = new MixedFileUpload(name, filename, contentType,
                    contentTransferEncoding, charset, size, minSize);
            fileUpload.setMaxSize(maxSize);
            checkHttpDataSize(fileUpload);
            List<HttpData> list = getList(request);
            list.add(fileUpload);
            return fileUpload;
        }
        MemoryFileUpload fileUpload = new MemoryFileUpload(name, filename, contentType,
                contentTransferEncoding, charset, size);
        fileUpload.setMaxSize(maxSize);
        checkHttpDataSize(fileUpload);
        return fileUpload;
    }

    @Override
    public void removeHttpDataFromClean(HttpRequest request, InterfaceHttpData data) {
        if (!(data instanceof HttpData)) {
            return;
        }

        // Do not use getList because it adds empty list to requestFileDeleteMap
        // if request is not found
        List<HttpData> list = requestFileDeleteMap.get(request);
        if (list == null) {
            return;
        }

        // Can't simply call list.remove(data), because different data items may be equal.
        // Need to check identity.
        Iterator<HttpData> i = list.iterator();
        while (i.hasNext()) {
            HttpData n = i.next();
            if (n == data) {
                i.remove();

                // Remove empty list to avoid memory leak
                if (list.isEmpty()) {
                    requestFileDeleteMap.remove(request);
                }

                return;
            }
        }
    }

    @Override
    public void cleanRequestHttpData(HttpRequest request) {
        List<HttpData> list = requestFileDeleteMap.remove(request);
        if (list != null) {
            for (HttpData data : list) {
                data.release();
            }
        }
    }

    @Override
    public void cleanAllHttpData() {
        Iterator<Entry<HttpRequest, List<HttpData>>> i = requestFileDeleteMap.entrySet().iterator();
        while (i.hasNext()) {
            Entry<HttpRequest, List<HttpData>> e = i.next();

            // Calling i.remove() here will cause "java.lang.IllegalStateException: Entry was removed"
            // at e.getValue() below

            List<HttpData> list = e.getValue();
            for (HttpData data : list) {
                data.release();
            }

            i.remove();
        }
    }

    @Override
    public void cleanRequestHttpDatas(HttpRequest request) {
        cleanRequestHttpData(request);
    }

    @Override
    public void cleanAllHttpDatas() {
        cleanAllHttpData();
    }
}