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BUG#: 5314
TITLE: IPC Refactoring

DESCRIPTION: This patch cleans up the IPC related classes. It (1) reorganizes
related classes into their own headers, (2) makes the mutex class recursive to
eliminate recursive lock exclusion logic, (3) reimplements condition variables,
renames dozens of global functions.

//%2006////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2000, 2001, 2002 BMC Software; Hewlett-Packard Development
// Company, L.P.; IBM Corp.; The Open Group; Tivoli Systems.
// Copyright (c) 2003 BMC Software; Hewlett-Packard Development Company, L.P.;
// IBM Corp.; EMC Corporation, The Open Group.
// Copyright (c) 2004 BMC Software; Hewlett-Packard Development Company, L.P.;
// IBM Corp.; EMC Corporation; VERITAS Software Corporation; The Open Group.
// Copyright (c) 2005 Hewlett-Packard Development Company, L.P.; IBM Corp.;
// EMC Corporation; VERITAS Software Corporation; The Open Group.
// Copyright (c) 2006 Hewlett-Packard Development Company, L.P.; IBM Corp.;
// EMC Corporation; Symantec Corporation; The Open Group.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// THE ABOVE COPYRIGHT NOTICE AND THIS PERMISSION NOTICE SHALL BE INCLUDED IN
// ALL COPIES OR SUBSTANTIAL PORTIONS OF THE SOFTWARE. THE SOFTWARE IS PROVIDED
// "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
// LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
// ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
//==============================================================================
//
// Author: Mike Day (mdday@us.ibm.com)
//
// Reworked By: Mike Brasher (m.brasher@inovadevelopment.com)
//
//%/////////////////////////////////////////////////////////////////////////////

#ifndef Pegasus_ReadWriteSem_h
#define Pegasus_ReadWriteSem_h

#include <Pegasus/Common/Config.h>
#include <Pegasus/Common/Linkage.h>
#include <Pegasus/Common/Semaphore.h>
#include <Pegasus/Common/Mutex.h>
#include <Pegasus/Common/AtomicInt.h>

#define PEG_SEM_READ 1
#define PEG_SEM_WRITE 2

PEGASUS_NAMESPACE_BEGIN

//==============================================================================
//
// Select the read-write-lock implementation for your platform:
//
//     PEGASUS_USE_POSIX_RWLOCK
//     PEGASUS_USE_SEMAPHORE_RWLOCK
//
//==============================================================================

#if defined(PEGASUS_PLATFORM_AIX_RS_IBMCXX)
# define PEGASUS_USE_POSIX_RWLOCK
#elif defined(PEGASUS_PLATFORM_HPUX_ACC)
# define PEGASUS_USE_POSIX_RWLOCK
#elif defined(PEGASUS_PLATFORM_OS400_ISERIES_IBM)
# define PEGASUS_USE_POSIX_RWLOCK
#elif defined(PEGASUS_PLATFORM_SOLARIS_SPARC_CC)
# define PEGASUS_USE_POSIX_RWLOCK
#elif defined(PEGASUS_PLATFORM_TRU64_ALPHA_DECCXX)
# define PEGASUS_USE_POSIX_RWLOCK
#elif defined(PEGASUS_PLATFORM_ZOS_ZSERIES_IBM)
# define PEGASUS_USE_POSIX_RWLOCK
#elif defined(PEGASUS_PLATFORM_VMS_IA64_DECCXX)
# define PEGASUS_USE_POSIX_RWLOCK
#elif defined(PEGASUS_PLATFORM_VMS_ALPHA_DECCXX)
# define PEGASUS_USE_POSIX_RWLOCK
#elif defined(PEGASUS_PLATFORM_LINUX_X86_64_GNU)
# define PEGASUS_USE_POSIX_RWLOCK
#else
# define PEGASUS_USE_SEMAPHORE_RWLOCK
#endif

//==============================================================================
//
// ReadWriteSemRep
//
//==============================================================================

#ifdef PEGASUS_USE_POSIX_RWLOCK
struct ReadWriteSemRep
{
    pthread_rwlock_t rwlock;
    ThreadType owner;
};
#endif /* PEGASUS_USE_POSIX_RWLOCK */

#ifdef PEGASUS_USE_SEMAPHORE_RWLOCK
struct ReadWriteSemRep
{
    Semaphore _rlock;
    Mutex _wlock;
    Mutex _internal_lock;
    ThreadType _owner;
    ReadWriteSemRep() : 
        _rlock(10), _wlock(), _internal_lock(), _owner(Threads::self())
    {
    }
};
#endif /* PEGASUS_USE_POSIX_RWLOCK */

//==============================================================================
//
// ReadWriteSem
//
//==============================================================================

class PEGASUS_COMMON_LINKAGE ReadWriteSem
{
public:

    ReadWriteSem();

    ~ReadWriteSem();

    // @exception Deadlock
    // @exception Permission
    // @exception WaitFailed
    inline void wait_read(ThreadType caller)
    {
        wait(PEG_SEM_READ, caller );
    }

    // @exception Deadlock
    // @exception Permission
    // @exception WaitFailed
    inline void wait_write(ThreadType caller)
    {
        wait(PEG_SEM_WRITE, caller);
    }

    // @exception Deadlock
    // @exception Permission
    // @exception AlreadyLocked
    // @exception WaitFailed
    inline void try_wait_read(ThreadType caller)
    {
        try_wait(PEG_SEM_READ, caller);
    }

    // @exception Deadlock
    // @exception Permission
    // @exception AlreadyLocked
    // @exception WaitFailed
    inline void try_wait_write(ThreadType caller)
    {
        try_wait(PEG_SEM_WRITE, caller);
    }

    // @exception Deadlock
    // @exception Permission
    // @exception TimeOut
    // @exception WaitFailed
    inline void timed_wait_read(ThreadType caller, int milliseconds)
    {
        timed_wait(PEG_SEM_READ, caller, milliseconds);
    }

    // @exception Deadlock
    // @exception Permission
    // @exception TimeOut
    // @exception WaitFailed
    inline void timed_wait_write(ThreadType caller, int milliseconds)
    {
        timed_wait(PEG_SEM_WRITE, caller, milliseconds);
    }

    // @exception Permission
    inline void unlock_read(ThreadType caller)
    {
        unlock(PEG_SEM_READ, caller);
    }

    // @exception Permission
    inline void unlock_write(ThreadType caller)
    {
        unlock(PEG_SEM_WRITE, caller);
    }

    int read_count() const;
    int write_count() const;

    // @exception Deadlock
    // @exception Permission
    // @exception WaitFailed
    // @exception TooManyReaders
    void wait(Uint32 mode, ThreadType caller);

    // @exception Deadlock
    // @exception Permission
    // @exception WaitFailed
    // @exception TooManyReaders
    void try_wait(Uint32 mode, ThreadType caller);

    // @exception Timeout
    // @exception Deadlock
    // @exception Permission
    // @exception WaitFailed
    // @exception TooManyReaders
    void timed_wait(Uint32 mode, ThreadType caller, int milliseconds);

    // @exception Permission
    void unlock(Uint32 mode, ThreadType caller);

private:
    AtomicInt _readers;
    AtomicInt _writers;
    ReadWriteSemRep _rwlock;
    friend void extricate_read_write(void *);
};

//==============================================================================
//
// ReadLock
//
//==============================================================================

class ReadLock
{
public:

    ReadLock(ReadWriteSem& rwsem) : _rwsem(rwsem)
    {
        _rwsem.wait_read(Threads::self());
    }

    ~ReadLock()
    {
        _rwsem.unlock_read(Threads::self());
    }

private:
    ReadWriteSem & _rwsem;
};

//==============================================================================
//
// WriteLock
//
//==============================================================================

class WriteLock
{
public:

    WriteLock(ReadWriteSem& rwsem) : _rwsem(rwsem)
    {
        _rwsem.wait_write(Threads::self());
    }

    ~WriteLock()
    {
        _rwsem.unlock_write(Threads::self());
    }

private:
    ReadWriteSem & _rwsem;
};

PEGASUS_NAMESPACE_END

#endif /* Pegasus_ReadWriteSem_h */