flock.h

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 //------------------------------------------------------------------------
// Project     : SDK Base
// Version     : 1.0
//
// Category    : Helpers
// Filename    : base/thread/include/flock.h
// Created by  : Steinberg, 1995
// Description : locks
//
//-----------------------------------------------------------------------------
// LICENSE
// (c) 2023, Steinberg Media Technologies GmbH, All Rights Reserved
//-----------------------------------------------------------------------------
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
// 
//   * Redistributions of source code must retain the above copyright notice, 
//     this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright notice,
//     this list of conditions and the following disclaimer in the documentation 
//     and/or other materials provided with the distribution.
//   * Neither the name of the Steinberg Media Technologies nor the names of its
//     contributors may be used to endorse or promote products derived from this 
//     software without specific prior written permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
// IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
// INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 
// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 
// OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE  OF THIS SOFTWARE, EVEN IF ADVISED
// OF THE POSSIBILITY OF SUCH DAMAGE.
//-----------------------------------------------------------------------------
 
//----------------------------------------------------------------------------------
//----------------------------------------------------------------------------------
#pragma once
 
#include "base/source/fobject.h"
#include "pluginterfaces/base/ftypes.h"
 
#if SMTG_PTHREADS
#include <pthread.h>
 
#elif SMTG_OS_WINDOWS
struct CRITSECT                         // CRITICAL_SECTION
{
    void* DebugInfo;                    // PRTL_CRITICAL_SECTION_DEBUG DebugInfo;
    Steinberg::int32 LockCount;         // LONG LockCount;
    Steinberg::int32 RecursionCount;    // LONG RecursionCount;
    void* OwningThread;                 // HANDLE OwningThread
    void* LockSemaphore;                // HANDLE LockSemaphore
    Steinberg::int32 SpinCount;         // ULONG_PTR SpinCount
};
#endif
 
namespace Steinberg {
namespace Base {
namespace Thread {
 
//------------------------------------------------------------------------
//------------------------------------------------------------------------
struct ILock
{
//------------------------------------------------------------------------
    virtual ~ILock () {}
 
    virtual void lock () = 0;
 
    virtual void unlock () = 0;
 
    virtual bool trylock () = 0;
//------------------------------------------------------------------------
};
 
//------------------------------------------------------------------------
//------------------------------------------------------------------------
class FLock : public ILock
{
public:
//------------------------------------------------------------------------
 
    FLock (const char8* name = "FLock");
 
    ~FLock () SMTG_OVERRIDE;
 
    //-- ILock -----------------------------------------------------------
    void lock () SMTG_OVERRIDE;
    void unlock () SMTG_OVERRIDE;
    bool trylock () SMTG_OVERRIDE;
 
//------------------------------------------------------------------------
protected:
#if SMTG_PTHREADS
    pthread_mutex_t mutex; 
 
#elif SMTG_OS_WINDOWS
    CRITSECT section; 
#endif
};
 
//------------------------------------------------------------------------
//------------------------------------------------------------------------
class FLockObject : public FObject, public FLock
{
public:
    OBJ_METHODS (FLockObject, FObject)
};
 
//------------------------------------------------------------------------
//------------------------------------------------------------------------
class FGuard
{
public:
//------------------------------------------------------------------------
 
    FGuard (ILock& _lock) : lock (_lock) { lock.lock (); }
 
    ~FGuard () { lock.unlock (); }
 
//------------------------------------------------------------------------
private:
    ILock& lock; 
};
 
//------------------------------------------------------------------------
//------------------------------------------------------------------------
class FConditionalGuard
{
public:
//------------------------------------------------------------------------
 
    FConditionalGuard (FLock* _lock) : lock (_lock)
    {
        if (lock)
            lock->lock ();
    }
 
    ~FConditionalGuard ()
    {
        if (lock)
            lock->unlock ();
    }
 
//------------------------------------------------------------------------
private:
    FLock* lock; 
};
 
} // Thread
} // Base
} // Steinberg