File indexing completed on 2024-04-14 03:52:50

 /*
     Implementation of the data protocol (rfc 2397)
 
     SPDX-FileCopyrightText: 2002, 2003 Leo Savernik <l.savernik@aon.at>
 
     SPDX-License-Identifier: LGPL-2.0-only
 */
 
 #include "dataprotocol_p.h"
 
 #include "global.h"
 #include "metadata.h"
 
 #include <QByteArray>
 #include <QStringDecoder>
 
 using namespace KIO;
 
 /** structure containing header information */
 struct DataHeader {
     QString mime_type; // MIME type of content (lowercase)
     MetaData attributes; // attribute/value pairs (attribute lowercase,
     //  value unchanged)
     bool is_base64; // true if data is base64 encoded
     QByteArray url; // reference to decoded url
     int data_offset; // zero-indexed position within url
     // where the real data begins. May point beyond
     // the end to indicate that there is no data
 };
 
 /** returns the position of the first occurrence of any of the given
  * characters @p c1 or comma (',') or semicolon (';') or buf.length()
  * if none is contained.
  *
  * @param buf buffer where to look for c
  * @param begin zero-indexed starting position
  * @param c1 character to find or '\0' to ignore
  */
 static int find(const QByteArray &buf, int begin, const char c1)
 {
     static const char comma = ',';
     static const char semicolon = ';';
     int pos = begin;
     int size = buf.length();
     while (pos < size) {
         const char ch = buf[pos];
         if (ch == comma || ch == semicolon || (c1 != '\0' && ch == c1)) {
             break;
         }
         pos++;
     } /*wend*/
     return pos;
 }
 
 /** extracts the string between the current position @p pos and the first
  * occurrence of either @p c1 or comma (',') or semicolon (';') exclusively
  * and updates @p pos to point at the found delimiter or at the end of the
  * buffer if neither character occurred.
  * @param buf buffer where to look for
  * @param pos zero-indexed position within buffer
  * @param c1 character to find or '\0' to ignore
  */
 static inline QString extract(const QByteArray &buf, int &pos, const char c1 = '\0')
 {
     int oldpos = pos;
     pos = find(buf, oldpos, c1);
     return QString::fromLatin1(buf.mid(oldpos, pos - oldpos));
 }
 
 /** ignores all whitespaces
  * @param buf buffer to operate on
  * @param pos position to shift to first non-whitespace character
  *  Upon return @p pos will either point to the first non-whitespace
  *  character or to the end of the buffer.
  */
 static inline void ignoreWS(const QByteArray &buf, int &pos)
 {
     int size = buf.length();
     while (pos < size && (buf[pos] == ' ' || buf[pos] == '\t')) {
         ++pos;
     }
 }
 
 /** parses a quoted string as per rfc 822.
  *
  * If trailing quote is missing, the whole rest of the buffer is returned.
  * @param buf buffer to operate on
  * @param pos position pointing to the leading quote
  * @return the extracted string. @p pos will be updated to point to the
  *  character following the trailing quote.
  */
 static QString parseQuotedString(const QByteArray &buf, int &pos)
 {
     int size = buf.length();
     QString res;
     res.reserve(size); // can't be larger than buf
     pos++; // jump over leading quote
     bool escaped = false; // if true means next character is literal
     bool parsing = true; // true as long as end quote not found
     while (parsing && pos < size) {
         const QChar ch = QLatin1Char(buf[pos++]);
         if (escaped) {
             res += ch;
             escaped = false;
         } else {
             switch (ch.unicode()) {
             case '"':
                 parsing = false;
                 break;
             case '\\':
                 escaped = true;
                 break;
             default:
                 res += ch;
                 break;
             } /*end switch*/
         } /*end if*/
     } /*wend*/
     res.squeeze();
     return res;
 }
 
 /** parses the header of a data url
  * @param url the data url
  * @param mimeOnly if the only interesting information is the MIME type
  * @return DataHeader structure with the header information
  */
 static DataHeader parseDataHeader(const QUrl &url, const bool mimeOnly)
 {
     DataHeader header_info;
 
     // initialize header info members
     header_info.mime_type = QStringLiteral("text/plain");
     header_info.attributes.insert(QStringLiteral("charset"), QStringLiteral("us-ascii"));
     header_info.is_base64 = false;
 
     // decode url and save it
     const QByteArray &raw_url = header_info.url = QByteArray::fromPercentEncoding(url.path(QUrl::FullyEncoded).toLatin1());
     const int raw_url_len = raw_url.length();
 
     header_info.data_offset = 0;
 
     // read MIME type
     if (raw_url_len == 0) {
         return header_info;
     }
     const QString mime_type = extract(raw_url, header_info.data_offset).trimmed();
     if (!mime_type.isEmpty()) {
         header_info.mime_type = mime_type;
     }
     if (mimeOnly) {
         return header_info;
     }
 
     if (header_info.data_offset >= raw_url_len) {
         return header_info;
     }
     // jump over delimiter token and return if data reached
     if (raw_url[header_info.data_offset++] == ',') {
         return header_info;
     }
 
     // read all attributes and store them
     bool data_begin_reached = false;
     while (!data_begin_reached && header_info.data_offset < raw_url_len) {
         // read attribute
         const QString attribute = extract(raw_url, header_info.data_offset, '=').trimmed();
         if (header_info.data_offset >= raw_url_len || raw_url[header_info.data_offset] != '=') {
             // no assignment, must be base64 option
             if (attribute == QLatin1String("base64")) {
                 header_info.is_base64 = true;
             }
         } else {
             header_info.data_offset++; // jump over '=' token
 
             // read value
             ignoreWS(raw_url, header_info.data_offset);
             if (header_info.data_offset >= raw_url_len) {
                 return header_info;
             }
 
             QString value;
             if (raw_url[header_info.data_offset] == '"') {
                 value = parseQuotedString(raw_url, header_info.data_offset);
                 ignoreWS(raw_url, header_info.data_offset);
             } else {
                 value = extract(raw_url, header_info.data_offset).trimmed();
             }
 
             // add attribute to map
             header_info.attributes[attribute.toLower()] = value;
 
         } /*end if*/
         if (header_info.data_offset < raw_url_len && raw_url[header_info.data_offset] == ',') {
             data_begin_reached = true;
         }
         header_info.data_offset++; // jump over separator token
     } /*wend*/
 
     return header_info;
 }
 
 DataProtocol::DataProtocol()
 {
 }
 
 DataProtocol::~DataProtocol() = default;
 
 void DataProtocol::get(const QUrl &url)
 {
     ref();
     // qDebug() << this;
 
     const DataHeader hdr = parseDataHeader(url, false);
 
     const int size = hdr.url.length();
     const int data_ofs = qMin(hdr.data_offset, size);
     // FIXME: string is copied, would be nice if we could have a reference only
     const QByteArray url_data = hdr.url.mid(data_ofs);
     QByteArray outData;
 
     if (hdr.is_base64) {
         // base64 stuff is expected to contain the correct charset, so we just
         // decode it and pass it to the receiver
         outData = QByteArray::fromBase64(url_data);
     } else {
         QStringDecoder codec(hdr.attributes[QStringLiteral("charset")].toLatin1().constData());
         if (codec.isValid()) {
             outData = QString(codec.decode(url_data)).toUtf8();
         } else {
             outData = url_data;
         } /*end if*/
     } /*end if*/
 
     // qDebug() << "emit mimeType@"<<this;
     Q_EMIT mimeType(hdr.mime_type);
     // qDebug() << "emit totalSize@"<<this;
     Q_EMIT totalSize(outData.size());
 
     // qDebug() << "emit setMetaData@"<<this;
     setAllMetaData(hdr.attributes);
 
     // qDebug() << "emit sendMetaData@"<<this;
     sendMetaData();
     // qDebug() << "(1) queue size " << dispatchQueue.size();
     // empiric studies have shown that this shouldn't be queued & dispatched
     Q_EMIT data(outData);
     // qDebug() << "(2) queue size " << dispatchQueue.size();
     dispatch_data(QByteArray{});
     // qDebug() << "(3) queue size " << dispatchQueue.size();
     dispatch_finished();
     // qDebug() << "(4) queue size " << dispatchQueue.size();
     deref();
 }
 
 /* --------------------------------------------------------------------- */
 
 void DataProtocol::mimetype(const QUrl &url)
 {
     ref();
     Q_EMIT mimeType(parseDataHeader(url, true).mime_type);
     Q_EMIT finished();
     deref();
 }
 
 /* --------------------------------------------------------------------- */
 
 #if !defined(TESTKIO)
 #include "moc_dataprotocol_p.cpp"
 #endif