gserver.cpp

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//
// Copyright (C) 2017 Graeme Walker
// 
// 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 3 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, see <http://www.gnu.org/licenses/>.
// ===
//
// gserver.cpp
//

#include "gdef.h"
#include "gnet.h"
#include "glimits.h"
#include "gserver.h"
#include "groot.h"
#include "gmonitor.h"
#include "gdebug.h"
#include "gtest.h"
#include "gassert.h"
#include <algorithm> // std::find()

GNet::ServerPeer::ServerPeer( Server::PeerInfo peer_info ) :
    m_address(peer_info.m_address) ,
    m_socket(peer_info.m_socket) ,
    m_sp(*this,*this,*m_socket.get(),0U) ,
    m_handle(peer_info.m_handle) ,
    m_delete_timer(*this,&ServerPeer::onTimeout,*this)
{
    G_ASSERT( m_socket.get() != nullptr ) ;
    G_DEBUG( "GNet::ServerPeer::ctor: [" << this << "]: " << logId() ) ;

    m_socket->addReadHandler( *this ) ;
    m_socket->addExceptionHandler( *this ) ;
    if( Monitor::instance() ) Monitor::instance()->addServerPeer(*this) ;
}

GNet::ServerPeer::~ServerPeer()
{
    G_DEBUG( "GNet::ServerPeer::dtor: [" << this << "]: fd " << logId() ) ;
    if( Monitor::instance() ) Monitor::instance()->removeServerPeer(*this) ;
    m_handle->reset() ;
    m_socket->dropReadHandler() ;
    m_socket->dropExceptionHandler() ;
}

std::string GNet::ServerPeer::logId() const
{
    return m_address.displayString() + "@" + m_socket->asString() ;
}

void GNet::ServerPeer::sslAccept()
{
    m_sp.sslAccept() ;
}

GNet::StreamSocket & GNet::ServerPeer::socket()
{
    G_ASSERT( m_socket.get() != nullptr ) ;
    return *m_socket.get() ;
}

void GNet::ServerPeer::readEvent()
{
    m_sp.readEvent() ;
}

void GNet::ServerPeer::onException( std::exception & e )
{
    G_DEBUG( "ServerPeer::onException: exception: " << e.what() ) ;
    doDelete( e.what() ) ;
}

void GNet::ServerPeer::doDelete( const std::string & reason )
{
    onDelete( reason ) ;
    m_delete_timer.startTimer( 0U ) ;
}

std::pair<bool,GNet::Address> GNet::ServerPeer::localAddress() const
{
    G_ASSERT( m_socket.get() != nullptr ) ;
    return m_socket->getLocalAddress() ;
}

std::pair<bool,GNet::Address> GNet::ServerPeer::peerAddress() const
{
    return std::pair<bool,Address>( true , m_address ) ;
}

std::string GNet::ServerPeer::peerCertificate() const
{
    return m_sp.peerCertificate() ;
}

void GNet::ServerPeer::onTimeout()
{
    doDeleteThis(1) ;
}

void GNet::ServerPeer::doDeleteThis( int )
{
    delete this ;
}

bool GNet::ServerPeer::send( const std::string & data , std::string::size_type offset )
{
    return m_sp.send( data , offset ) ;
}

bool GNet::ServerPeer::send( const std::vector<std::pair<const char*,size_t> > & segments )
{
    return m_sp.send( segments ) ;
}

void GNet::ServerPeer::writeEvent()
{
    try
    {
        if( m_sp.writeEvent() )
            onSendComplete() ;
    }
    catch( std::exception & e )
    {
        G_DEBUG( "GNet::ServerPeer::writeEvent: exception: " << e.what() ) ;
        doDelete( e.what() ) ;
    }
}

// ===

GNet::Server::Server( const Address & listening_address )
{
    init( listening_address ) ;
}

GNet::Server::Server() :
    m_cleaned_up(false)
{
}

void GNet::Server::init( const Address & listening_address )
{
    m_cleaned_up = false ;
    m_socket.reset( new StreamSocket(listening_address.domain()) ) ;
    G_DEBUG( "GNet::Server::init: listening on socket " << m_socket->asString() << " with address " << listening_address.displayString() ) ;
    {
        G::Root claim_root ;
        m_socket->bind( listening_address ) ;
    }
    m_socket->listen( G::limits::net_listen_queue ) ;
    m_socket->addReadHandler( *this ) ;
}

bool GNet::Server::canBind( const Address & address , bool do_throw )
{
    StreamSocket socket( address.domain() ) ;
    bool ok = false ;
    {
        G::Root claim_root ;
        ok = socket.canBindHint( address ) ;
    }
    if( !ok && do_throw )
        throw CannotBind( address.displayString() ) ;
    return ok ;
}

GNet::Server::~Server()
{
    serverCleanup() ;
}

void GNet::Server::serverCleanup()
{
    try
    {
        if( ! m_cleaned_up )
        {
            m_cleaned_up = true ;
            serverCleanupCore() ;
        }
    }
    catch(...) // dtor
    {
    }
}

void GNet::Server::serverCleanupCore()
{
    for( PeerList::iterator p = m_peer_list.begin() ; p != m_peer_list.end() ; ++p )
    {
        ServerPeerHandle handle = *p ;
        if( handle.peer() != nullptr )
        {
            G_DEBUG( "GNet::Server::serverCleanupCore: deleting peer: [" << handle.peer() << "]" ) ;
            handle.peer()->doDeleteThis(1) ;
        }
    }
}

std::pair<bool,GNet::Address> GNet::Server::address() const
{
    std::pair<bool,Address> result( false , Address::defaultAddress() ) ;
    if( m_socket.get() != nullptr )
        result = m_socket->getLocalAddress() ;
    return result ;
}

void GNet::Server::readEvent()
{
    // read-event-on-listening-port => new connection to accept

    G_DEBUG( "GNet::Server::readEvent: " << this ) ;
    G_ASSERT( m_socket.get() != nullptr ) ;

    // take this opportunity to do garbage collection
    collectGarbage() ;

    // accept the connection
    PeerInfo peer_info ;
    accept( peer_info ) ;
    G_DEBUG( "GNet::Server::readEvent: new connection from " << peer_info.m_address.displayString() 
        << " on " << peer_info.m_socket->asString() ) ;

    // keep track of peer objects
    m_peer_list.push_back( ServerPeerHandle() ) ;
    peer_info.m_handle = &m_peer_list.back() ;

    // create the peer object -- newPeer() implementations will normally 
    // catch their exceptions to avoid terminating the server
    //
    ServerPeer * peer = newPeer( peer_info ) ;

    // commit or roll back
    if( peer == nullptr )
    {
        m_peer_list.pop_back() ;
        G_DEBUG( "GNet::Server::readEvent: connection rejected from " << peer_info.m_address.displayString() ) ;
    }
    else
    {
        m_peer_list.back().set( peer ) ;
        G_DEBUG( "GNet::Server::readEvent: new connection accepted: " << peer->logId() ) ;
    }
}

void GNet::Server::accept( PeerInfo & peer_info )
{
    {
        G::Root claim_root ;
        AcceptPair accept_pair = m_socket->accept() ;
        peer_info.m_socket = accept_pair.first ;
        peer_info.m_address = accept_pair.second ;
    }
    G_ASSERT( peer_info.m_socket.get() != nullptr ) ;
}

void GNet::Server::collectGarbage()
{
    // cleanup empty handles, where peer objects have deleted themselves
    G_DEBUG( "GNet::Server::collectGarbage" ) ;
    for( PeerList::iterator p = m_peer_list.begin() ; p != m_peer_list.end() ; )
    {
        ServerPeerHandle handle = *p ;
        if( handle.peer() == nullptr )
        {
            G_DEBUG( "GNet::Server::collectGarbage: [" << handle.old() << "]" ) ;
            p = m_peer_list.erase( p ) ;
        }
        else
        {
            ++p ;
        }
    }
}

void GNet::Server::writeEvent()
{
    G_DEBUG( "GNet::Server::writeEvent" ) ;
}

// ===

GNet::Server::PeerInfo::PeerInfo() :
    m_address(Address::defaultAddress()) ,
    m_handle(nullptr)
{
}

// ===

GNet::ServerPeerHandle::ServerPeerHandle() :
    m_p(nullptr) ,
    m_old(nullptr)
{
}

void GNet::ServerPeerHandle::reset()
{
    m_p = nullptr ;
}

GNet::ServerPeer * GNet::ServerPeerHandle::peer()
{
    return m_p ;
}

GNet::ServerPeer * GNet::ServerPeerHandle::old()
{
    return m_old ;
}

void GNet::ServerPeerHandle::set( ServerPeer * p )
{
    m_p = p ;
    m_old = p ;
}

/// \file gserver.cpp