xwords/relay/crefmgr.cpp

/* -*-mode: C; fill-column: 78; c-basic-offset: 4; -*- */

/* 
 * Copyright 2005 by Eric House (fixin@peak.org).  All rights reserved.
 *
 * 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.
 *
 * 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  02111-1307, USA.
 */

#include <assert.h>
#include <pthread.h>

#include "crefmgr.h"
#include "cref.h"
#include "mlock.h"

class SocketStuff {
 public:
    SocketStuff( CookieRef* cref )
        : m_cref(cref)
        {        
            pthread_mutex_init( &m_writeMutex, NULL );
        }
    ~SocketStuff() { pthread_mutex_destroy( &m_writeMutex ); }
    CookieRef* m_cref;
    pthread_mutex_t m_writeMutex; /* so only one thread writes at a time */
};

/* static */ CRefMgr*
CRefMgr::Get() 
{
    static CRefMgr* instance = NULL;
    if ( instance == NULL ) {
        instance = new CRefMgr();
    }
    return instance;
} /* Get */

CRefMgr::CRefMgr()
{
    /* should be using pthread_once() here */
    pthread_mutex_init( &m_guard, NULL );
    pthread_rwlock_init( &m_cookieMapRWLock, NULL );
}

CRefMgr::~CRefMgr()
{
}

CookieRef*
CRefMgr::getMakeCookieRef_locked( const char* cookie, CookieID connID )
{
    pthread_mutex_lock( &m_guard );

    CookieRef* cref = connID == 0 ? NULL: getCookieRef_impl( connID );

    if ( cref == NULL ) {       /* need to keep looking? */

        CookieID newId = CookieIdForName( cookie );
    
        if ( newId == 0 ) {     /* not in the system */
            cref = AddNew( string(cookie), connID );
        } else {
            cref = getCookieRef_impl( newId );
        }
    }

    if ( cref == NULL ) {
        pthread_mutex_unlock( &m_guard );
    }

    return cref;
} /* getMakeCookieRef_locked */

CookieID
CRefMgr::CookieIdForName( const char* name )
{
    CookieRef* cref = NULL;
    string s(name);

    RWReadLock rwl( &m_cookieMapRWLock );

    CookieMap::iterator iter = m_cookieMap.begin();
    while ( iter != m_cookieMap.end() ) {
        cref = iter->second;
        if ( cref->Name() == s && cref->NotFullyConnected() ) {
            return cref->GetCookieID();
        }
        ++iter;
    }
    return 0;
} /* CookieIdForName */

void
CRefMgr::Associate( int socket, CookieRef* cref )
{
    MutexLock ml( &m_SocketStuffMutex );
    SocketMap::iterator iter = m_SocketStuff.find( socket );
    if ( iter == m_SocketStuff.end() ) {
        logf( "replacing existing cref/threadID pair for socket %d", socket );
    }
    
    SocketStuff* stuff = new SocketStuff( cref );
    m_SocketStuff.insert( pair< int, SocketStuff* >( socket, stuff ) );
}

pthread_mutex_t* 
CRefMgr::GetWriteMutexForSocket( int socket )
{
    MutexLock ml( &m_SocketStuffMutex );
    SocketMap::iterator iter = m_SocketStuff.find( socket );
    if ( iter != m_SocketStuff.end() ) {
        SocketStuff* stuff = iter->second;
        return &stuff->m_writeMutex;
    }
    assert( 0 );
} /* GetWriteMutexForSocket */

void 
CRefMgr::RemoveSocketRefs( int socket )
{
    SafeCref scr( socket );
    if ( scr.IsValid() ) {
        scr.Remove( socket );
    }
}

void
CRefMgr::PrintSocketInfo( int socket, string& out )
{
    SafeCref scr( socket );
    if ( scr.IsValid() ) {
        char buf[64];

        snprintf( buf, sizeof(buf), "* socket: %d\n", socket );
        out += buf;

        snprintf( buf, sizeof(buf), "  in cookie: %s\n", scr.Name().c_str() );
        out += buf;
    }
}

/* static */ SocketsIterator 
CRefMgr::MakeSocketsIterator()
{
    pthread_mutex_lock( &m_SocketStuffMutex );
    SocketsIterator iter( m_SocketStuff.begin(), m_SocketStuff.end(), 
                          &m_SocketStuffMutex );
    return iter;
}

CookieRef* 
CRefMgr::getCookieRef_locked( CookieID cookieID )
{
    pthread_mutex_lock( &m_guard );

    CookieRef* cref = getCookieRef_impl( cookieID );

    if ( cref == NULL ) {
        pthread_mutex_unlock( &m_guard );
    }

    return cref;
} /* getCookieRef_locked */

CookieRef* 
CRefMgr::getCookieRef_locked( int socket )
{
    pthread_mutex_lock( &m_guard );
    CookieRef* cref = NULL;

    CookieMap::iterator iter = m_cookieMap.begin();
    while ( iter != m_cookieMap.end() ) {
        CookieRef* tmp = iter->second;
        if ( tmp->HasSocket( socket ) ) {
            cref = tmp;
            break;
        }
        ++iter;
    }

    if ( cref == NULL ) {
        pthread_mutex_unlock( &m_guard );
    }

    return cref;
} /* getCookieRef_locked */

int
CRefMgr::checkCookieRef_locked( CookieRef* cref )
{
    int exists = 1;
    assert( cref != NULL );
    pthread_mutex_lock( &m_guard );

    pthread_mutex_t* cref_mutex = m_crefMutexes[cref];
    logf( "checkCookieRef_locked: cref_mutex=%p", cref_mutex );

    if ( cref_mutex == NULL ) {
        pthread_mutex_unlock( &m_guard );
        exists = 0;
    }

    return exists;
} /* checkCookieRef_locked */

int
CRefMgr::LockCref( CookieRef* cref )
{
    /* assertion: m_guard is locked */

    pthread_mutex_t* cref_mutex = m_crefMutexes[cref];
    if ( cref_mutex == NULL ) {
        cref_mutex = (pthread_mutex_t*)malloc( sizeof( *cref_mutex ) );
        pthread_mutex_init( cref_mutex, NULL );
        m_crefMutexes[cref] = cref_mutex;
    }
    pthread_mutex_lock( cref_mutex );

    pthread_mutex_unlock( &m_guard );
    return 1;
} /* LockCref */

void
CRefMgr::UnlockCref( CookieRef* cref )
{
    pthread_mutex_t* cref_mutex = m_crefMutexes[cref];
    pthread_mutex_unlock( cref_mutex );
}

CookieRef*
CRefMgr::AddNew( string s, CookieID id )
{
    RWWriteLock rwl( &m_cookieMapRWLock );
    logf( "making new cref" );
    CookieRef* ref = new CookieRef( s, id );
    m_cookieMap.insert( pair<CookieID, CookieRef*>(ref->GetCookieID(), ref ) );
    logf( "paired cookie %s with id %d", s.c_str(), ref->GetCookieID() );
    return ref;
} /* AddNew */

void
CRefMgr::Delete( CookieRef* cref )
{
    RWWriteLock rwl( &m_cookieMapRWLock );

    CookieMap::iterator iter = m_cookieMap.begin();
    while ( iter != m_cookieMap.end() ) {
        CookieRef* ref = iter->second;
        if ( ref == cref ) {
            logf( "erasing cref" );
            m_cookieMap.erase( iter );
            break;
        }
        ++iter;
    }

    pthread_mutex_t* cref_mutex = m_crefMutexes[cref];
    pthread_mutex_unlock( cref_mutex );
    pthread_mutex_destroy( cref_mutex );
    free( cref_mutex );

    map<CookieRef*,pthread_mutex_t*>::iterator iter2;
    iter2 = m_crefMutexes.find(cref);
    m_crefMutexes.erase( iter2 );

    logf( "CRefMgr::Delete done" );
}

void
CRefMgr::Delete( CookieID id )
{
    CookieRef* cref = getCookieRef_impl( id );
    if ( cref != NULL ) {
        Delete( cref );
    }
} /* Delete */

void
CRefMgr::Delete( const char* name )
{
    CookieID id = CookieIdForName( name );
    Delete( id );
} /* Delete */

CookieRef* 
CRefMgr::getCookieRef_impl( CookieID cookieID )
{
    CookieRef* ref = NULL;
    RWReadLock rwl( &m_cookieMapRWLock );

    CookieMap::iterator iter = m_cookieMap.find( cookieID );
    while ( iter != m_cookieMap.end() ) {
        CookieRef* sec = iter->second;
        if ( sec->GetCookieID() == cookieID ) {
            ref = sec;
            break;
        }
        ++iter;
    }
    return ref;
}

void
CRefMgr::CheckHeartbeats( time_t now )
{
    RWReadLock rwl( &m_cookieMapRWLock );
    CookieMap::iterator iter = m_cookieMap.begin();
    while ( iter != m_cookieMap.end() ) {
        SafeCref scr( iter->second );
        if ( scr.IsValid() ) {
            scr.CheckHeartbeats( now );
        }
        ++iter;
    }
} /* CheckHeartbeats */

/* static */ CookieMapIterator
CRefMgr::GetCookieIterator()
{
    CookieMapIterator iter;
    return iter;
}


CookieMapIterator::CookieMapIterator()
     : _iter( CRefMgr::Get()->m_cookieMap.begin() )
{
}

CookieID
CookieMapIterator::Next()
{
    CookieID id = 0;
    if ( _iter != CRefMgr::Get()->m_cookieMap.end() ) {
        CookieRef* cref = _iter->second;
        id = cref->GetCookieID();
        ++_iter;
    }
    return id;
}

//////////////////////////////////////////////////////////////////////////////
// SafeCref
//////////////////////////////////////////////////////////////////////////////

SafeCref::SafeCref( const char* cookie, CookieID connID )
     : m_cref( NULL )
     , m_connID(0)
     , m_mgr( CRefMgr::Get() )
{
    CookieRef* cref = m_mgr->getMakeCookieRef_locked( cookie, connID );
    if ( cref != NULL ) {
        if ( m_mgr->LockCref( cref ) ) {
            m_cref = cref;
        }
    }
}

SafeCref::SafeCref( CookieID connID )
     : m_cref( NULL )
     , m_connID(0)
     , m_mgr( CRefMgr::Get() )
{
    CookieRef* cref = m_mgr->getCookieRef_locked( connID );
    if ( cref != NULL ) {
        if ( m_mgr->LockCref( cref ) ) {
            m_cref = cref;
        }
    }
}

SafeCref::SafeCref( int socket )
     : m_cref( NULL )
     , m_connID(0)
     , m_mgr( CRefMgr::Get() )
{
    CookieRef* cref = m_mgr->getCookieRef_locked( socket );
    if ( cref != NULL ) {
        if ( m_mgr->LockCref( cref ) ) {
            m_cref = cref;
        }
    }
}

SafeCref::SafeCref( CookieRef* cref )
     : m_cref( NULL )
     , m_connID(0)
     , m_mgr( CRefMgr::Get() )
{
    if ( m_mgr->checkCookieRef_locked( cref ) ) {
        if ( m_mgr->LockCref( cref ) ) {
            m_cref = cref;
        }
    }
}

SafeCref::~SafeCref()
{
    if ( m_cref != NULL ) {
        if ( m_cref->ShouldDie() ) {
            m_mgr->Delete( m_cref );
        } else {
            m_mgr->UnlockCref( m_cref );
        }
    }
}