ReadHelper.ct

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//
// Copyright (c) 2020 Fraunhofer Institute for Applied Information Technology (FIT)
//                    Network Research Group (NET)
//                    Schloss Birlinghoven, 53754 Sankt Augustin, GERMANY
//                    Contact: support@wiback.org
//
// This file is part of the SENF code tree.
// It is licensed under the 3-clause BSD License (aka New BSD License).
// See LICENSE.txt in the top level directory for details or visit
// https://opensource.org/licenses/BSD-3-Clause
//


/** \file
    \brief ReadHelper non-inline template implementation */

#include "ReadHelper.ih"

// Custom includes
#include <boost/bind.hpp>
#include <senf/Utils/Exception.hh>

#define prefix_
//-/////////////////////////////////////////////////////////////////////////////////////////////////

template <class Handle>
prefix_ senf::ReadHelper<Handle>::ReadHelper(Handle handle, std::string::size_type maxSize,
                                                    InternalPredicate * predicate, Callback cb)
    : handle_(handle),
      fde_("senf::ReadHelper", boost::bind(&ReadHelper::dispatchProcess,ptr(this), handle, _1),
           handle, scheduler::FdEvent::EV_READ),
      maxSize_(maxSize), predicate_(predicate), callback_(cb), errno_(0), complete_(false)
{
    // Here we add a *static* member taking a *smart* pointer as first
    // argument instead of a simple bound-member as callback to the
    // scheduler. This ensures, that the refcount is at least 1 as
    // long as the helper is registered with the scheduler.
}

template <class Handle>
prefix_ void senf::ReadHelper<Handle>::revoke()
{
    ptr guard (this); // To ensure, 'this' is deleted only after this method terminates ...
    fde_.disable();
    fde_.action(0); // Remove smart pointer reference to this
}

template <class Handle>
prefix_ void
senf::ReadHelper<Handle>::dispatchProcess(ptr helper, Handle handle, int event)
{
    // since we have a 'ptr' argument, the instance cannot be deleted
    // before this method returns
    helper->process(handle,event);
}

template <class Handle>
prefix_ void senf::ReadHelper<Handle>::process(Handle handle,int event)
{
    try {
        if (event != scheduler::FdEvent::EV_READ)
            throw SystemException(EPIPE SENF_EXC_DEBUGINFO);
        std::string rcv;
        handle.read(rcv, maxSize_ - data_.size());
        data_.append(rcv);
        std::string::size_type n = predicate_ ? (*predicate_)(data_) : std::string::npos;
        if (n != std::string::npos || data_.size() >= maxSize_ || rcv.size() == 0) {
            complete_ = true;
            if (n < data_.size()) {
                tail_.assign(data_,n,std::string::npos);
                data_.erase(n);
            }
        }
    }
    catch (senf::SystemException const & ex) {
        errno_ = ex.errorNumber();
        done();
        return;
    }
    if (complete_)
        done();
}

template <class Handle>
prefix_ void senf::ReadHelper<Handle>::done()
{
    revoke();
    callback_(ptr(this));
}

template <class Handle>
template <class Predicate>
prefix_ std::string::size_type
senf::ReadHelper<Handle>::InternalPredicate::Dispatcher<Predicate>::
operator()(std::string const & data)
{
    return predicate(data);
}

//-/////////////////////////////////////////////////////////////////////////////////////////////////
#undef prefix_


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