NpCheck.h

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// Copyright (c) 2004-2008 AGEIA Technologies, Inc. All rights reserved.
// Copyright (c) 2001-2004 NovodeX AG. All rights reserved.  
 
#ifndef NP_CHECK_H
#define NP_CHECK_H
 
#include "foundation/PxSimpleTypes.h"
 
namespace physx
{
 
class NpScene;
 
// RAII wrapper around the PxScene::startRead() method, note that this
// object does not acquire any scene locks, it is an error checking only mechanism
class NpReadCheck
{
public: 
    NpReadCheck(const NpScene* scene, const char* functionName);
    ~NpReadCheck();
private:
    const NpScene* mScene;
    const char* mName;
    PxU32 mErrorCount;
};
 
// RAII wrapper around the PxScene::startWrite() method, note that this
// object does not acquire any scene locks, it is an error checking only mechanism
class NpWriteCheck
{
public: 
    NpWriteCheck(NpScene* scene, const char* functionName, bool allowReentry=true);
    ~NpWriteCheck();
 
private:
 
    NpScene* mScene;
    const char* mName;
    bool mAllowReentry;
    PxU32 mErrorCount;
};
 
#if (PX_DEBUG || PX_CHECKED)
    // Creates a scoped read check object that detects whether appropriate scene locks
    // have been acquired and checks if reads/writes overlap, this macro should typically
    // be placed at the beginning of any const API methods that are not multi-thread safe, 
    // the error conditions checked can be summarized as:
    
    // 1. PxSceneFlag::eREQUIRE_RW_LOCK was specified but PxScene::lockRead() was not yet called
    // 2. Other threads were already writing, or began writing during the object lifetime
    #define NP_READ_CHECK(npScenePtr) NpReadCheck npReadCheck(static_cast<const NpScene*>(npScenePtr), __FUNCTION__);
 
    // Creates a scoped write check object that detects whether appropriate scene locks
    // have been acquired and checks if reads/writes overlap, this macro should typically
    // be placed at the beginning of any non-const API methods that are not multi-thread safe. 
    // By default re-entrant  write calls by the same thread are allowed, the error conditions 
    // checked can be summarized as:
    
    // 1. PxSceneFlag::eREQUIRE_RW_LOCK was specified but PxScene::lockWrite() was not yet called
    // 2. Other threads were already reading, or began reading during the object lifetime
    // 3. Other threads were already writing, or began writing during the object lifetime
    #define NP_WRITE_CHECK(npScenePtr) NpWriteCheck npWriteCheck(npScenePtr, __FUNCTION__);
 
    // Creates a scoped write check object that disallows re-entrant writes, this is used by
    // the NpScene::simulate method to detect when callbacks make write calls to the API
    #define NP_WRITE_CHECK_NOREENTRY(npScenePtr) NpWriteCheck npWriteCheck(npScenePtr, __FUNCTION__, false);
#else
    #define NP_READ_CHECK(npScenePtr)
    #define NP_WRITE_CHECK(npScenePtr)
    #define NP_WRITE_CHECK_NOREENTRY(npScenePtr)
#endif
 
/*
    PT: suggested ordering for Np-level checks & macros:
 
    PX_PROFILE_ZONE(...);
    NP_WRITE_CHECK(...);
    PX_CHECK_AND_RETURN_XXX(...);
    PX_CHECK_SCENE_API_WRITE_FORBIDDEN_AND_RETURN_VAL(...);
    PX_SIMD_GUARD;
 
    Current rationale:
 
    - profile zone first to include the cost of the checks in the profiling results.
 
    - NP_WRITE_CHECK before PX_CHECK macros. I tried both and the DLL size is smaller with NP_WRITE_CHECK macros first.
 
    - PX_CHECK_SCENE_API_WRITE_FORBIDDEN_AND_RETURN_VAL after PX_CHECK_AND_RETURN macros, because contrary to the others
    these macros don't vanish in Release builds. So we want to group together NP_WRITE_CHECK and PX_CHECK_AND_RETURN macros
    (the ones that do vanish). That way we can eventually skip them with a runtime flag.
 
    - PX_SIMD_GUARD last. No need to take the guard before the PX_CHECK_SCENE_API are done, it would only generate more
    guard dtor code when the macro eary exits.
*/
}
 
#endif