Method nextImpl

src/Server/HTTP/HTMLForm.cpp:320–353

}

bool HTMLForm::MultipartReadBuffer::nextImpl()
{
    if (boundary_hit)
        return false;

    chassert(position() >= in.position());

    in.position() = position();

    /// We expect to start from the first symbol after EOL, so we can put checkpoint
    /// and safely try to read til the next EOL and check for boundary.
    in.setCheckpoint();

    /// FIXME: there is an extra copy because we cannot traverse PeekableBuffer from checkpoint to position()
    ///        since it may store different data parts in different sub-buffers,
    ///        anyway calling makeContinuousMemoryFromCheckpointToPos() will also make an extra copy.
    /// According to RFC2046 the preceding CRLF is a part of boundary line.
    std::string line = readLine(false);
    boundary_hit = startsWith(line, "\r\n" + boundary);
    bool has_next = !boundary_hit && !line.empty();

    if (has_next)
        /// If we don't make sure that memory is contiguous then situation may happen, when part of the line is inside internal memory
        /// and other part is inside sub-buffer, thus we'll be unable to setup our working buffer properly.
        in.makeContinuousMemoryFromCheckpointToPos();

    in.rollbackToCheckpoint(true);

    /// Rolling back to checkpoint may change underlying buffers.
    /// Limit readable data to a single line.
    BufferBase::set(in.position(), line.size(), 0);

    return has_next;
}

}