/*
 * $Id: ESICustomParser.cc,v 1.10 2007/05/29 13:31:37 amosjeffries Exp $
 *
 * DEBUG: section 86    ESI processing
 * AUTHOR: Robert Collins
 *
 * SQUID Web Proxy Cache          http://www.squid-cache.org/
 * ----------------------------------------------------------
 *
 *  Squid is the result of efforts by numerous individuals from
 *  the Internet community; see the CONTRIBUTORS file for full
 *  details.   Many organizations have provided support for Squid's
 *  development; see the SPONSORS file for full details.  Squid is
 *  Copyrighted (C) 2001 by the Regents of the University of
 *  California; see the COPYRIGHT file for full details.  Squid
 *  incorporates software developed and/or copyrighted by other
 *  sources; see the CREDITS file for full details.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *  
 *  This program is distributed in the hope that it will be useful,
 ;  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *  
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 */

#include "squid.h"
#include "ESICustomParser.h"
#include "Trie.h"
#include "TrieCharTransform.h"
#include "Array.h"

Trie *ESICustomParser::SearchTrie=NULL;

RegisterESIParser("custom", ESICustomParser);

Trie *
ESICustomParser::GetTrie()
{
    if (SearchTrie)
        return SearchTrie;

    SearchTrie = new Trie(new TrieCaseless);

    static const ESITAG_t ESITAG_value = ESITAG;

    assert (SearchTrie->add
            ("<esi:",5,(void *)&ESITAG_value));

    static const ESITAG_t ESIENDTAG_value = ESIENDTAG;

    assert (SearchTrie->add
            ("</esi:",6,(void *)&ESIENDTAG_value));

    static const ESITAG_t ESICOMMENT_value = ESICOMMENT;

    assert (SearchTrie->add
            ("<!--",4,(void *)&ESICOMMENT_value));

    return SearchTrie;
}

ESICustomParser::ESICustomParser(ESIParserClient *aClient) : theClient (aClient)
{}

ESICustomParser::~ESICustomParser()
{
    theClient = NULL;
}

char const *
ESICustomParser::findTag(char const *buffer, size_t bufferLength)
{
    size_t myOffset (0);
    ESITAG_t *resulttype = NULL;

    while (myOffset < bufferLength &&
            (resulttype = static_cast<ESITAG_t *>(GetTrie()->findPrefix (buffer + myOffset, bufferLength - myOffset)))
            == NULL)
        ++myOffset;

    if (myOffset == bufferLength)
        return NULL;

    debugs(86, 9, "ESICustomParser::findTag: found " << *resulttype);

    lastTag = *resulttype;

    return buffer + myOffset;
}

bool
ESICustomParser::parse(char const *dataToParse, size_t const lengthOfData, bool const endOfStream)
{
    debugs(86, 9, "ESICustomParser::parse: Appending data to internal buffer");
    content.append (dataToParse, lengthOfData);

    if (!endOfStream) {
        return true;
    }

    size_t openESITags (0);
    char const *currentPos = content.buf();
    size_t remainingCount = content.size();
    char const *tag = NULL;

    while ((tag = findTag(currentPos, remainingCount))) {
        if (tag - currentPos)
            theClient->parserDefault (currentPos,tag - currentPos);

        switch (lastTag) {

        case ESITAG: {
                ++openESITags;
                char *tagEnd = strchr(const_cast<char *>(tag), '>');

                if (!tagEnd) {
                    error = "Could not find end ('>') of tag";
                    return false;
                }

                if (tagEnd - tag > (ssize_t)remainingCount) {
                    error = "Tag ends beyond the parse buffer.";
                    return false;
                }

                if (*(tagEnd - 1) == '/')
                    --openESITags;

                char * endofName = strpbrk(const_cast<char *>(tag), w_space);

                if (endofName > tagEnd)
                    endofName = const_cast<char *>(tagEnd);

                *endofName = '\0';

                *tagEnd = '\0';

                Vector<char *>attributes;

                char *attribute = const_cast<char *>(endofName + 1);

                while (attribute > tag && attribute < tagEnd) {
                    /* leading spaces */

                    while (attribute < tagEnd && (xisspace(*attribute) || (*attribute == '/')))
                        ++attribute;

                    if (! (attribute < tagEnd))
                        break;

                    /* attribute name */
                    attributes.push_back(attribute);

                    char *nextSpace = strpbrk(attribute, w_space);

                    char *equals = strchr(attribute, '=');

                    if (!equals) {
                        error = "Missing attribute value.";
                        return false;
                    }

                    if (nextSpace && nextSpace < equals)
                        *nextSpace = '\0';
                    else
                        *equals = '\0';

                    ++equals;

                    while (equals < tagEnd && xisspace(*equals))
                        ++equals;

                    char sep = *equals;

                    if (sep != '\'' && sep != '"') {
                        error = "Unknown identifier (";
                        error.append (sep);
                        error.append (")");
                        return false;
                    }

                    char *value = equals + 1;
                    char *end = strchr (value, sep);
                    attributes.push_back(value);
                    *end = '\0';
                    attribute = end + 1;
                }

                theClient->start (tag + 1, (const char **)attributes.items, attributes.size() >> 1);
                /* TODO: attributes */

                if (*(tagEnd - 1) == '/')
                    theClient->end (tag + 1);

                remainingCount -= tagEnd - currentPos + 1;

                currentPos = tagEnd + 1;
            }

            break;

        case ESIENDTAG: {
                if (!openESITags)
                    return false;

                char const *tagEnd = strchr(tag, '>');

                if (!tagEnd)
                    return false;

                if (tagEnd - tag > (ssize_t)remainingCount)
                    return false;

                char * endofName = strpbrk(const_cast<char *>(tag), w_space);

                if (endofName > tagEnd)
                    endofName = const_cast<char *>(tagEnd);

                *endofName = '\0';

                theClient->end (tag + 2);

                --openESITags;

                remainingCount -= tagEnd - currentPos + 1;

                currentPos = tagEnd + 1;
            }

            break;

        case ESICOMMENT: {
                /* Further optimisation potential:
                 * 1) recognize end comments for esi and don't callback on 
                 * comments.
                 * 2) provide the comment length to the caller.
                 */
                /* Comments must not be nested, without CDATA
                 * and we don't support CDATA
                 */
                char *commentEnd = strstr (const_cast<char *>(tag), "-->");

                if (!commentEnd) {
                    error = "missing end of comment";
                    return false;
                }

                if (commentEnd - tag > (ssize_t)remainingCount) {
                    error = "comment ends beyond parse buffer";
                    return false;
                }

                *commentEnd = '\0';
                theClient->parserComment (tag + 4);
                remainingCount -= commentEnd - currentPos + 3;
                currentPos = commentEnd + 3;
            }

            break;
            break;

        default:
            fatal ("unknown ESI tag type found");
        };

        /*
         * Find next esi tag (open or closing) or comment
         * send tag, or full comment text
         * rinse
         */
    }

    if (remainingCount)
        theClient->parserDefault (currentPos,remainingCount);

    debugs(86, 5, "ESICustomParser::parse: Finished parsing, will return " << !openESITags);

    if (openESITags)
        error = "ESI Tags still open";

    return !openESITags;
}

long int
ESICustomParser::lineNumber() const
{
    /* We don't track lines in the body */
    return 0;
}

char const *
ESICustomParser::errorString() const
{
    if (error.size())
        return error.buf();
    else
        return "Parsing error strings not implemented";
}