source-engine/tier0/vcrmode.cpp

//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose: 
//
// $NoKeywords: $
//
//===========================================================================//

#include "pch_tier0.h"

#ifdef _WIN32
#define WIN_32_LEAN_AND_MEAN
#include <windows.h>
#include <winsock.h>
#endif

#include <time.h>
#include <assert.h>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include "tier0/vcrmode.h"
#include "tier0/dbg.h"

// FIXME: We totally have a bad tier dependency here
#include "inputsystem/inputenums.h"
												
#ifndef NO_VCR

#define PvRealloc realloc
#define PvAlloc malloc

											
												
#define VCR_RuntimeAssert(x)	VCR_RuntimeAssertFn(x, #x)

double g_flLastVCRFloatTimeValue;												

bool		g_bExpectingWindowProcCalls = false;

IVCRHelpers	*g_pHelpers = 0;

FILE		*g_pVCRFile = NULL;
VCRMode_t	g_VCRMode = VCR_Disabled;
VCRMode_t	g_OldVCRMode = VCR_Invalid;		// Stored temporarily between SetEnabled(0)/SetEnabled(1) blocks.
int			g_iCurEvent = 0;

int			g_CurFilePos = 0;				// So it knows when we're done playing back.
int			g_FileLen = 0;					

VCREvent	g_LastReadEvent = (VCREvent)-1;	// Last VCR_ReadEvent() call.
int			g_LastEventThread;				// The thread index of the thread that g_LastReadEvent is intended for.

int			g_bVCREnabled = 0;



// ------------------------------------------------------------------------------------------ //
// These wrappers exist because for some reason thread-blocking functions nuke the
// last function on the call stack, so it's very hard to debug without these wrappers.
// ------------------------------------------------------------------------------------------ //
inline unsigned long Wrap_WaitForSingleObject( HANDLE hObj, DWORD duration )
{
	return WaitForSingleObject( hObj, duration );
}

inline unsigned long Wrap_WaitForMultipleObjects( uint32 nHandles, const void **pHandles, int bWaitAll, uint32 timeout )
{
	return WaitForMultipleObjects( nHandles, (const HANDLE *)pHandles, bWaitAll, timeout );
}

inline void Wrap_EnterCriticalSection( CRITICAL_SECTION *pSection )
{
	EnterCriticalSection( pSection );
}



// ------------------------------------------------------------------------------------------ //
// Threadsafe debugging file output.
// ------------------------------------------------------------------------------------------ //
FILE *g_pDebugFile = 0;
CRITICAL_SECTION g_DebugFileCS;

class CCSInit
{
public:
	CCSInit()
	{
		InitializeCriticalSection( &g_DebugFileCS );
	}
	~CCSInit()
	{
		DeleteCriticalSection( &g_DebugFileCS );
	}
} g_DebugFileCS222;

void VCR_Debug( const char *pMsg, ... )
{
	va_list marker;
	va_start( marker, pMsg );

	EnterCriticalSection( &g_DebugFileCS );

	if ( !g_pDebugFile )
		g_pDebugFile = fopen( "c:\\vcrdebug.txt", "wt" );

	if ( g_pDebugFile )
	{
		vfprintf( g_pDebugFile, pMsg, marker );
		fflush( g_pDebugFile );
	}

	LeaveCriticalSection( &g_DebugFileCS );
	
	va_end( marker );
}



// ------------------------------------------------------------------------------------------ //
// VCR threading support.
// It uses 2 methods to implement threading, depending on whether you're recording or not.
//
// If you're recording, it uses critical sections to control access to the events written
// into the file.
//
// During playback, every thread waits on a windows event handle. When a VCR event is done
// being read out, it peeks ahead and sees which thread should get the next VCR event 
// and it wakes up that thread.
// ------------------------------------------------------------------------------------------ //

#define MAX_VCR_THREADS	512
class CVCRThreadInfo
{
public:
	DWORD m_ThreadID;		// The Windows thread ID.
	HANDLE m_hWaitEvent;	// Used to get the signal that there is an event for this thread.
	bool m_bEnabled;		// By default, this is true, but it can be set to false to temporarily disable a thread's VCR usage.
};
CVCRThreadInfo *g_pVCRThreads = NULL;	// This gets allocated to MAX_VCR_THREADS size if we're doing any VCR recording or playback.
int g_nVCRThreads = 0;

// Used to avoid writing the thread ID into events that are for the main thread.
DWORD g_VCRMainThreadID = 0;

// Set to true if VCR_Start is ever called.
bool g_bVCRStartCalled = false;


unsigned short GetCurrentVCRThreadIndex()
{
	DWORD hCurThread = GetCurrentThreadId();
	for ( int i=0; i < g_nVCRThreads; i++ )
	{
		if ( g_pVCRThreads[i].m_ThreadID == hCurThread )
			return (unsigned short)i;
	}
	Error( "GetCurrentVCRThreadInfo: no matching thread." );
	return 0;
}


CVCRThreadInfo* GetCurrentVCRThreadInfo()
{
	return &g_pVCRThreads[ GetCurrentVCRThreadIndex() ];
}


static void VCR_SignalNextEvent();


// ------------------------------------------------------------------------------------------ //
// This manages which thread gets the next event.
// ------------------------------------------------------------------------------------------ //

CRITICAL_SECTION g_VCRCriticalSection;

class CVCRThreadSafe
{
public:
	CVCRThreadSafe()
	{
		m_bSignalledNextEvent = false;

		if ( g_VCRMode == VCR_Record )
		{
			Wrap_EnterCriticalSection( &g_VCRCriticalSection );
		}
		else if ( g_VCRMode == VCR_Playback )
		{
			// Wait until our event is signalled, telling us that we are the next guy in line for an event.
			WaitForSingleObject( GetCurrentVCRThreadInfo()->m_hWaitEvent, INFINITE );
		}
	}
	~CVCRThreadSafe()
	{
		if ( g_VCRMode == VCR_Record )
		{
			LeaveCriticalSection( &g_VCRCriticalSection );
		}
		else if ( g_VCRMode == VCR_Playback && !m_bSignalledNextEvent )
		{
			// Set the event for the next thread's VCR event.
			VCR_SignalNextEvent();
		}
	}
	void SignalNextEvent()
	{
		VCR_SignalNextEvent();
		m_bSignalledNextEvent = true;
	}

private:
	bool m_bSignalledNextEvent;
};

class CVCRThreadSafeInitter
{
public:
	CVCRThreadSafeInitter()
	{
		InitializeCriticalSection( &g_VCRCriticalSection );
	}
	~CVCRThreadSafeInitter()
	{
		DeleteCriticalSection( &g_VCRCriticalSection );
	}
} g_VCRThreadSafeInitter;

#define VCR_THREADSAFE CVCRThreadSafe vcrThreadSafe;




// ---------------------------------------------------------------------- //
// Internal functions.
// ---------------------------------------------------------------------- //

static void VCR_Error( const char *pFormat, ... )
{
	#ifdef _DEBUG
		// Figure out which thread we're in, for the debugger.
		DWORD curThreadId = GetCurrentThreadId();
		int iCurThread = -1;
		for ( int i=0; i < g_nVCRThreads; i++ )
		{
			if ( g_pVCRThreads[i].m_ThreadID == curThreadId )
				iCurThread = i;
		}

		DebuggerBreak();
	#endif

	char str[256];
	va_list marker;
	va_start( marker, pFormat );
	_vsnprintf( str, sizeof( str ), pFormat, marker );
	va_end( marker );

	g_pHelpers->ErrorMessage( str );
	VCREnd();
}

static void VCR_RuntimeAssertFn(int bAssert, char const *pStr)
{
	if(!bAssert)
	{
		VCR_Error( "*** VCR ASSERT FAILED: %s ***\n", pStr );
	}
}

static void VCR_Read(void *pDest, int size)
{
	if(!g_pVCRFile)
	{
		memset(pDest, 0, size);
		return;
	}

	fread(pDest, 1, size, g_pVCRFile);
	
	g_CurFilePos += size;
	
	VCR_RuntimeAssert(g_CurFilePos <= g_FileLen);
	
	if(g_CurFilePos >= g_FileLen)
	{
		VCREnd();
	}
}

template<class T>
static void VCR_ReadVal(T &val)
{
	VCR_Read(&val, sizeof(val));
}

static void VCR_Write(void const *pSrc, int size)
{
	fwrite(pSrc, 1, size, g_pVCRFile);
	fflush(g_pVCRFile);
}

template<class T>
static void VCR_WriteVal(T &val)
{
	VCR_Write(&val, sizeof(val));
}



void VCR_SignalNextEvent()
{
	// When this function is called, we know that we are the only thread that is accessing the VCR file.
	unsigned char event;
	VCR_Read( &event, 1 );

	// Verify that we're in the correct thread for this event.
	unsigned short threadID;
	if ( event & 0x80 )
	{
		VCR_ReadVal( threadID );
		event &= ~0x80;
	}
	else
	{
		threadID = 0;
	}

	// Must be a valid thread ID.
	if ( threadID >= g_nVCRThreads )
	{
		Error( "VCR_ReadEvent: invalid threadID (%d).", threadID );
	}

	// Now signal the next thread.
	g_LastReadEvent = (VCREvent)event;
	g_LastEventThread = threadID;
	SetEvent( g_pVCRThreads[threadID].m_hWaitEvent );
}


static VCREvent VCR_ReadEvent()
{
	return g_LastReadEvent;
}


static void VCR_WriteEvent( VCREvent event )
{
	unsigned char cEvent = (unsigned char)event;
	
	unsigned short threadID = GetCurrentVCRThreadIndex();
	if ( threadID == 0 )
	{
		VCR_Write( &cEvent, 1 );
	}
	else
	{
		cEvent |= 0x80;
		VCR_Write( &cEvent, 1 );
		
		VCR_WriteVal( threadID );
	}
}

static void VCR_IncrementEvent()
{
	++g_iCurEvent;
}

static void VCR_Event(VCREvent type)
{
	if ( g_VCRMode == VCR_Disabled )
		return;

	VCR_IncrementEvent();
	if(g_VCRMode == VCR_Record)
	{
		VCR_WriteEvent(type);
	}
	else
	{
		VCREvent currentEvent = VCR_ReadEvent();
		VCR_RuntimeAssert( currentEvent == type );
	}
}


// ---------------------------------------------------------------------- //
// VCR trace interface.
// ---------------------------------------------------------------------- //

class CVCRTrace : public IVCRTrace
{
public:
	virtual VCREvent	ReadEvent()
	{
		return VCR_ReadEvent();
	}

	virtual void		Read( void *pDest, int size )
	{
		VCR_Read( pDest, size );
	}
};

static CVCRTrace g_VCRTrace;


// ---------------------------------------------------------------------- //
// VCR interface.
// ---------------------------------------------------------------------- //

static int VCR_Start( char const *pFilename, bool bRecord, IVCRHelpers *pHelpers )
{
	unsigned long version;
	
	g_VCRMainThreadID = GetCurrentThreadId();
	g_bVCRStartCalled = true;

	
	// Setup the initial VCR thread list.
	g_pVCRThreads = new CVCRThreadInfo[MAX_VCR_THREADS];
	g_pVCRThreads[0].m_ThreadID = GetCurrentThreadId();
	g_pVCRThreads[0].m_hWaitEvent = CreateEvent( NULL, false, false, NULL );
	g_pVCRThreads[0].m_bEnabled = true;
	g_nVCRThreads = 1;


	g_pHelpers = pHelpers;
	
	VCREnd();

	g_OldVCRMode = VCR_Invalid;
	if ( bRecord )
	{
		char *pCommandLine = GetCommandLine();
		if ( !strstr( pCommandLine, "-nosound" ) )
			Error( "VCR record: must use -nosound." );

		g_pVCRFile = fopen( pFilename, "wb" );
		if( g_pVCRFile )
		{
			// Write the version.
			version = VCRFILE_VERSION;
			VCR_Write(&version, sizeof(version));

			g_VCRMode = VCR_Record;
			return TRUE;
		}
		else
		{
			return FALSE;
		}
	}
	else
	{
		g_pVCRFile = fopen( pFilename, "rb" );
		if( g_pVCRFile )
		{
			// Get the file length.
			fseek(g_pVCRFile, 0, SEEK_END);
			g_FileLen = ftell(g_pVCRFile);
			fseek(g_pVCRFile, 0, SEEK_SET);
			g_CurFilePos = 0;

			// Verify the file version.
			VCR_Read(&version, sizeof(version));
			if(version != VCRFILE_VERSION)
			{
				assert(!"VCR_Start: invalid file version");
				VCREnd();
				return FALSE;
			}
			
			g_VCRMode = VCR_Playback;
			VCR_SignalNextEvent(); // Signal the first thread for its event.
			return TRUE;
		}
		else
		{
			return FALSE;
		}
	}
}


static void VCR_End()
{
	if ( g_pVCRFile )
	{
		fclose(g_pVCRFile);
		g_pVCRFile = NULL;
	}

	if ( g_VCRMode == VCR_Playback )
	{
		// It's going to get screwy now, especially if we have threads, so just exit.
		#ifdef _DEBUG
			if ( IsDebuggerPresent() )
				DebuggerBreak();
		#endif

		TerminateProcess( GetCurrentProcess(), 1 );
	}

	g_VCRMode = VCR_Disabled;
}


static IVCRTrace* VCR_GetVCRTraceInterface()
{
	return &g_VCRTrace;
}


static VCRMode_t VCR_GetMode()
{
	return g_VCRMode;
}


static void VCR_SetEnabled( int bEnabled )
{
	if ( g_VCRMode != VCR_Disabled )
	{
		g_pVCRThreads[ GetCurrentVCRThreadIndex() ].m_bEnabled = (bEnabled != 0);
	}
}


inline bool IsVCRModeEnabledForThisThread()
{
	if ( g_VCRMode == VCR_Disabled || !g_bVCRStartCalled )
		return false;

	return g_pVCRThreads[ GetCurrentVCRThreadIndex() ].m_bEnabled;
}


static void VCR_SyncToken(char const *pToken)
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return;

	unsigned char len;

	VCR_THREADSAFE;
	VCR_Event(VCREvent_SyncToken);

	if(g_VCRMode == VCR_Record)
	{
		int intLen = strlen( pToken );
		assert( intLen <= 255 );

		len = (unsigned char)intLen;
		
		VCR_Write(&len, 1);
		VCR_Write(pToken, len);
	}
	else if(g_VCRMode == VCR_Playback)
	{
		char test[256];

		VCR_Read(&len, 1);
		VCR_Read(test, len);
		
		VCR_RuntimeAssert( len == (unsigned char)strlen(pToken) );
		VCR_RuntimeAssert( memcmp(pToken, test, len) == 0 );
	}
}


static double VCR_Hook_Sys_FloatTime(double time)
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return time;

	VCR_THREADSAFE;
	VCR_Event(VCREvent_Sys_FloatTime);

	if(g_VCRMode == VCR_Record)
	{
		VCR_Write(&time, sizeof(time));
	}
	else if(g_VCRMode == VCR_Playback)
	{
		VCR_Read(&time, sizeof(time));
		g_flLastVCRFloatTimeValue = time;
	}

	return time;
}



static int VCR_Hook_PeekMessage(
	struct tagMSG *msg, 
	void *hWnd, 
	unsigned int wMsgFilterMin, 
	unsigned int wMsgFilterMax, 
	unsigned int wRemoveMsg
	)
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return PeekMessage((MSG*)msg, (HWND)hWnd, wMsgFilterMin, wMsgFilterMax, wRemoveMsg);

	VCR_THREADSAFE;

	if( g_VCRMode == VCR_Record )
	{
		// The trapped windowproc calls should be flushed by the time we get here.
		int ret;
		ret = PeekMessage( (MSG*)msg, (HWND)hWnd, wMsgFilterMin, wMsgFilterMax, wRemoveMsg );

		// NOTE: this must stay AFTER the trapped window proc calls or things get 
		// read back in the wrong order.
		VCR_Event( VCREvent_PeekMessage );

		VCR_WriteVal(ret);
		if(ret)
			VCR_Write(msg, sizeof(MSG));

		return ret;
	}
	else
	{
		Assert( g_VCRMode == VCR_Playback );

		// Playback any windows messages that got trapped.
		VCR_Event( VCREvent_PeekMessage );

		int ret;
		VCR_ReadVal(ret);
		if(ret)
			VCR_Read(msg, sizeof(MSG));

		return ret;
	}
}


void VCR_Hook_RecordGameMsg( const InputEvent_t& event )
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return;

	VCR_THREADSAFE;

	if ( g_VCRMode == VCR_Record )
	{
		VCR_Event( VCREvent_GameMsg );
		
		char val = 1;
		VCR_WriteVal( val );
		VCR_WriteVal( event.m_nType );
		VCR_WriteVal( event.m_nData );
		VCR_WriteVal( event.m_nData2 );
		VCR_WriteVal( event.m_nData3 );
	}
}


void VCR_Hook_RecordEndGameMsg()
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return;

	VCR_THREADSAFE;

	if ( g_VCRMode == VCR_Record )
	{
		VCR_Event( VCREvent_GameMsg );
		char val = 0;
		VCR_WriteVal( val );	// record that there are no more messages.
	}
}


bool VCR_Hook_PlaybackGameMsg( InputEvent_t* pEvent )
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return false;

	VCR_THREADSAFE;

	if ( g_VCRMode == VCR_Playback )
	{
		VCR_Event( VCREvent_GameMsg );
		
		char bMsg;
		VCR_ReadVal( bMsg );
		if ( bMsg )
		{
			VCR_ReadVal( pEvent->m_nType );
			VCR_ReadVal( pEvent->m_nData );
			VCR_ReadVal( pEvent->m_nData2 );
			VCR_ReadVal( pEvent->m_nData3 );
			return true;
		}
	}
	
	return false;
}


static void VCR_Hook_GetCursorPos(struct tagPOINT *pt)
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
	{
		GetCursorPos(pt);
		return;
	}

	VCR_THREADSAFE;

	VCR_Event(VCREvent_GetCursorPos);

	if(g_VCRMode == VCR_Playback)
	{
		VCR_ReadVal(*pt);
	}
	else
	{
		GetCursorPos(pt);

		if(g_VCRMode == VCR_Record)
		{
			VCR_WriteVal(*pt);
		}
	}
}


static void VCR_Hook_ScreenToClient(void *hWnd, struct tagPOINT *pt)
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
	{
		ScreenToClient((HWND)hWnd, pt);
		return;
	}

	VCR_THREADSAFE;
	VCR_Event(VCREvent_ScreenToClient);

	if(g_VCRMode == VCR_Playback)
	{
		VCR_ReadVal(*pt);
	}
	else
	{
		ScreenToClient((HWND)hWnd, pt);

		if(g_VCRMode == VCR_Record)
		{
			VCR_WriteVal(*pt);
		}
	}
}


static int VCR_Hook_recvfrom(int s, char *buf, int len, int flags, struct sockaddr *from, int *fromlen)
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
	{
		return recvfrom((SOCKET)s, buf, len, flags, from, fromlen);
	}

	VCR_THREADSAFE;
	VCR_Event(VCREvent_recvfrom);

	int ret;
	if ( g_VCRMode == VCR_Playback )
	{
		// Get the result from our file.
		VCR_Read(&ret, sizeof(ret));
		if(ret == SOCKET_ERROR)
		{
			int err;
			VCR_ReadVal(err);
			WSASetLastError(err);
		}
		else
		{
			VCR_Read( buf, ret );

			char bFrom;
			VCR_ReadVal( bFrom );
			if ( bFrom )
			{
				VCR_Read( from, *fromlen );
			}
		}
	}
	else
	{
		ret = recvfrom((SOCKET)s, buf, len, flags, from, fromlen);

		if ( g_VCRMode == VCR_Record )
		{
			// Record the result.
			VCR_Write(&ret, sizeof(ret));
			if(ret == SOCKET_ERROR)
			{
				int err = WSAGetLastError();
				VCR_WriteVal(err);
			}
			else
			{
				VCR_Write( buf, ret );
				
				char bFrom = !!from;
				VCR_WriteVal( bFrom );
				if ( bFrom )
					VCR_Write( from, *fromlen );
			}
		}
	}

	return ret;
}


static int VCR_Hook_recv(int s, char *buf, int len, int flags)
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
	{
		return recv( (SOCKET)s, buf, len, flags );
	}

	VCR_THREADSAFE;
	VCR_Event(VCREvent_recv);

	int ret;
	if ( g_VCRMode == VCR_Playback )
	{
		// Get the result from our file.
		VCR_Read(&ret, sizeof(ret));
		if(ret == SOCKET_ERROR)
		{
			int err;
			VCR_ReadVal(err);
			WSASetLastError(err);
		}
		else
		{
			VCR_Read( buf, ret );
		}
	}
	else
	{
		ret = recv( (SOCKET)s, buf, len, flags );

		if ( g_VCRMode == VCR_Record )
		{
			// Record the result.
			VCR_Write(&ret, sizeof(ret));
			if(ret == SOCKET_ERROR)
			{
				int err = WSAGetLastError();
				VCR_WriteVal(err);
			}
			else
			{
				VCR_Write( buf, ret );
			}
		}
	}

	return ret;
}


static int VCR_Hook_send(int s, const char *buf, int len, int flags)
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
	{
		return send( (SOCKET)s, buf, len, flags );
	}

	VCR_THREADSAFE;
	VCR_Event(VCREvent_send);

	int ret;
	if ( g_VCRMode == VCR_Playback )
	{
		// Get the result from our file.
		VCR_Read(&ret, sizeof(ret));
		if(ret == SOCKET_ERROR)
		{
			int err;
			VCR_ReadVal(err);
			WSASetLastError(err);
		}
	}
	else
	{
		ret = send( (SOCKET)s, buf, len, flags );

		if ( g_VCRMode == VCR_Record )
		{
			// Record the result.
			VCR_Write(&ret, sizeof(ret));
			if(ret == SOCKET_ERROR)
			{
				int err = WSAGetLastError();
				VCR_WriteVal(err);
			}
		}
	}

	return ret;
}


static void VCR_Hook_Cmd_Exec(char **f)
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return;

	VCR_THREADSAFE;
	VCR_Event(VCREvent_Cmd_Exec);

	if(g_VCRMode == VCR_Playback)
	{
		int len;

		VCR_Read(&len, sizeof(len));
		if(len == -1)
		{
			*f = NULL;
		}
		else
		{
			*f = (char*)PvAlloc(len);
			VCR_Read(*f, len);
		}
	}
	else if(g_VCRMode == VCR_Record)
	{
		int len;
		char *str = *f;

		if(str)
		{
			len = strlen(str)+1;
			VCR_Write(&len, sizeof(len));
			VCR_Write(str, len);
		}
		else
		{
			len = -1;
			VCR_Write(&len, sizeof(len));
		}
	}
}


static char* VCR_Hook_GetCommandLine()
{
	// This function is special in that it can be called before VCR mode is initialized.
	// In this special case, just return the command line.
	if ( !g_pVCRThreads )
		return GetCommandLine();

	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return GetCommandLine();

	VCR_THREADSAFE;
	VCR_Event(VCREvent_CmdLine);

	int len;
	char *ret;

	if(g_VCRMode == VCR_Playback)
	{
		VCR_Read(&len, sizeof(len));
		ret = new char[len];
		VCR_Read(ret, len);
	}
	else
	{
		ret = GetCommandLine();

		if(g_VCRMode == VCR_Record)
		{
			len = strlen(ret) + 1;
			VCR_WriteVal(len);
			VCR_Write(ret, len);
		}
	}
	
	return ret;
}


static long VCR_Hook_RegOpenKeyEx( void *hKey, const char *lpSubKey, unsigned long ulOptions, unsigned long samDesired, void *pHKey )
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return RegOpenKeyEx( (HKEY)hKey, lpSubKey, ulOptions, samDesired, (PHKEY)pHKey );

	VCR_THREADSAFE;
	VCR_Event(VCREvent_RegOpenKeyEx);

	long ret;
	if(g_VCRMode == VCR_Playback)
	{
		VCR_ReadVal(ret); // (don't actually write anything to the person's registry when playing back).
	}
	else
	{
		ret = RegOpenKeyEx( (HKEY)hKey, lpSubKey, ulOptions, samDesired, (PHKEY)pHKey );

		if(g_VCRMode == VCR_Record)
			VCR_WriteVal(ret);
	}

	return ret;
}


static long VCR_Hook_RegSetValueEx(void *hKey, tchar const *lpValueName, unsigned long Reserved, unsigned long dwType, unsigned char const *lpData, unsigned long cbData)
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return RegSetValueEx((HKEY)hKey, lpValueName, Reserved, dwType, lpData, cbData);

	VCR_THREADSAFE;
	VCR_Event(VCREvent_RegSetValueEx);

	long ret;
	if(g_VCRMode == VCR_Playback)
	{
		VCR_ReadVal(ret); // (don't actually write anything to the person's registry when playing back).
	}
	else
	{
		ret = RegSetValueEx((HKEY)hKey, lpValueName, Reserved, dwType, lpData, cbData);

		if(g_VCRMode == VCR_Record)
			VCR_WriteVal(ret);
	}

	return ret;
}


static long VCR_Hook_RegQueryValueEx(void *hKey, tchar const *lpValueName, unsigned long *lpReserved, unsigned long *lpType, unsigned char *lpData, unsigned long *lpcbData)
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return RegQueryValueEx((HKEY)hKey, lpValueName, lpReserved, lpType, lpData, lpcbData);

	VCR_THREADSAFE;
	VCR_Event(VCREvent_RegQueryValueEx);

	// Doesn't support this being null right now (although it would be trivial to add support).
	assert(lpData);
	
	long ret;
	unsigned long dummy = 0;
	if(g_VCRMode == VCR_Playback)
	{
		VCR_ReadVal(ret);
		VCR_ReadVal(lpType ? *lpType : dummy);
		VCR_ReadVal(*lpcbData);
		VCR_Read(lpData, *lpcbData);
	}
	else
	{
		ret = RegQueryValueEx((HKEY)hKey, lpValueName, lpReserved, lpType, lpData, lpcbData);

		if(g_VCRMode == VCR_Record)
		{
			VCR_WriteVal(ret);
			VCR_WriteVal(lpType ? *lpType : dummy);
			VCR_WriteVal(*lpcbData);
			VCR_Write(lpData, *lpcbData);
		}
	}

	return ret;
}


static long VCR_Hook_RegCreateKeyEx(void *hKey, char const *lpSubKey, unsigned long Reserved, char *lpClass, unsigned long dwOptions, 
	unsigned long samDesired, void *lpSecurityAttributes, void *phkResult, unsigned long *lpdwDisposition)
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return RegCreateKeyEx((HKEY)hKey, lpSubKey, Reserved, lpClass, dwOptions, samDesired, (LPSECURITY_ATTRIBUTES)lpSecurityAttributes, (HKEY*)phkResult, lpdwDisposition);

	VCR_THREADSAFE;
	VCR_Event(VCREvent_RegCreateKeyEx);

	long ret;
	if(g_VCRMode == VCR_Playback)
	{
		VCR_ReadVal(ret); // (don't actually write anything to the person's registry when playing back).
	}
	else
	{
		ret = RegCreateKeyEx((HKEY)hKey, lpSubKey, Reserved, lpClass, dwOptions, samDesired, (LPSECURITY_ATTRIBUTES)lpSecurityAttributes, (HKEY*)phkResult, lpdwDisposition);

		if(g_VCRMode == VCR_Record)
			VCR_WriteVal(ret);
	}

	return ret;
}


static void VCR_Hook_RegCloseKey(void *hKey)
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
	{
		RegCloseKey( (HKEY)hKey );
		return;
	}

	VCR_THREADSAFE;
	VCR_Event(VCREvent_RegCloseKey);

	if(g_VCRMode == VCR_Playback)
	{
	}
	else
	{
		RegCloseKey((HKEY)hKey);
	}
}


int VCR_Hook_GetNumberOfConsoleInputEvents( void *hInput, unsigned long *pNumEvents )
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return GetNumberOfConsoleInputEvents( (HANDLE)hInput, pNumEvents );

	VCR_THREADSAFE;
	VCR_Event( VCREvent_GetNumberOfConsoleInputEvents );

	char ret;
	if ( g_VCRMode == VCR_Playback )
	{
		VCR_ReadVal( ret );
		VCR_ReadVal( *pNumEvents );
	}
	else
	{
		ret = (char)GetNumberOfConsoleInputEvents( (HANDLE)hInput, pNumEvents );

		if ( g_VCRMode == VCR_Record )
		{
			VCR_WriteVal( ret );
			VCR_WriteVal( *pNumEvents );
		}
	}

	return ret;
}


int	VCR_Hook_ReadConsoleInput( void *hInput, void *pRecs, int nMaxRecs, unsigned long *pNumRead )
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return ReadConsoleInput( (HANDLE)hInput, (INPUT_RECORD*)pRecs, nMaxRecs, pNumRead );

	VCR_THREADSAFE;
	VCR_Event( VCREvent_ReadConsoleInput );

	char ret;
	if ( g_VCRMode == VCR_Playback )
	{
		VCR_ReadVal( ret );
		if ( ret )
		{
			VCR_ReadVal( *pNumRead );
			VCR_Read( pRecs, *pNumRead * sizeof( INPUT_RECORD ) );
		}
	}
	else
	{
		ret = (char)ReadConsoleInput( (HANDLE)hInput, (INPUT_RECORD*)pRecs, nMaxRecs, pNumRead );

		if ( g_VCRMode == VCR_Record )
		{
			VCR_WriteVal( ret );
			if ( ret )
			{
				VCR_WriteVal( *pNumRead );
				VCR_Write( pRecs, *pNumRead * sizeof( INPUT_RECORD ) );
			}
		}
	}

	return ret;
}


void VCR_Hook_LocalTime( struct tm *today )
{
	// We just provide a wrapper on this function so we can protect access to time() everywhere.
	time_t ltime;
	time( &ltime );
	tm *pTime = localtime( &ltime );
	memcpy( today, pTime, sizeof( *today ) );

	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return;

	VCR_THREADSAFE;
	
	VCR_Event( VCREvent_LocalTime );
	if ( g_VCRMode == VCR_Playback )
	{
		VCR_Read( today, sizeof( *today ) );
	}
	else if ( g_VCRMode == VCR_Record )
	{
		VCR_Write( today, sizeof( *today ) );
	}
}


void VCR_Hook_Time( long *today )
{
	// We just provide a wrapper on this function so we can protect access to time() everywhere.
	// NOTE: For 64-bit systems we should eventually get a function that takes a time_t, but we should have
	//       until about 2038 to do that before we overflow a long.
	time_t curTime;
	time( &curTime );

	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
	{
		*today = (long)curTime;
		return;
	}

	VCR_THREADSAFE;
	
	VCR_Event( VCREvent_Time );
	if ( g_VCRMode == VCR_Playback )
	{
		VCR_Read( &curTime, sizeof( curTime ) );
	}
	else if ( g_VCRMode == VCR_Record )
	{
		VCR_Write( &curTime, sizeof( curTime ) );
	}
	
	*today = (long)curTime;
}


short VCR_Hook_GetKeyState( int nVirtKey )
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return ::GetKeyState( nVirtKey );

	VCR_THREADSAFE;
	VCR_Event( VCREvent_GetKeyState );

	short ret;
	if ( g_VCRMode == VCR_Playback )
	{
		VCR_ReadVal( ret );
	}
	else
	{
		ret = ::GetKeyState( nVirtKey );
		if ( g_VCRMode == VCR_Record )
			VCR_WriteVal( ret );
	}

	return ret;
}


void VCR_GenericRecord( const char *pEventName, const void *pData, int len )
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return;

	VCR_THREADSAFE;
	VCR_Event( VCREvent_Generic );

	if ( g_VCRMode != VCR_Record )
		Error( "VCR_GenericRecord( %s ): not recording a VCR file", pEventName );

	// Write the event name (or 255 if none).
	int nameLen = 255;
	if ( pEventName )
	{
		nameLen = strlen( pEventName ) + 1;
		if ( nameLen >= 255 )
		{
			VCR_Error( "VCR_GenericRecord( %s ): nameLen too long (%d)", pEventName, nameLen );
			return;
		}
	}
	unsigned char ucNameLen = (unsigned char)nameLen;
	VCR_WriteVal( ucNameLen );
	VCR_Write( pEventName, ucNameLen );

	// Write the data.
	VCR_WriteVal( len );
	VCR_Write( pData, len );
}	


int VCR_GenericPlaybackInternal( const char *pEventName, void *pOutData, int maxLen, bool bForceSameLen, bool bForceSameContents )
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() || g_VCRMode != VCR_Playback )
		Error( "VCR_Playback( %s ): not playing back a VCR file", pEventName );

	VCR_THREADSAFE;
	VCR_Event( VCREvent_Generic );

	unsigned char nameLen;
	VCR_ReadVal( nameLen );
	if ( nameLen != 255 )
	{
		char testName[512];
		VCR_Read( testName, nameLen );
		if ( strcmp( pEventName, testName ) != 0 )
		{
			VCR_Error( "VCR_GenericPlayback( %s ) - event name does not match '%s'", pEventName, testName );
			return 0;
		}
	}

	int dataLen;
	VCR_ReadVal( dataLen );
	if ( dataLen > maxLen )
	{
		VCR_Error( "VCR_GenericPlayback( %s ) - generic data too long (greater than maxLen: %d)", pEventName, maxLen );
		return 0;
	}
	else if ( bForceSameLen && dataLen != maxLen )
	{
		VCR_Error( "VCR_GenericPlayback( %s ) - data size in file (%d) different than desired (%d)", pEventName, dataLen, maxLen );
		return 0;
	}

	if ( bForceSameContents )
	{
		if ( !bForceSameLen )
			Error( "bForceSameContents and !bForceSameLen not allowed." );

		static char *pTempData = new char[dataLen];
		static int tempDataLen = dataLen;
		if ( tempDataLen < dataLen )
		{
			delete [] pTempData;
			pTempData = new char[dataLen];
			tempDataLen = dataLen;
		}
		
		VCR_Read( pTempData, dataLen );
		if ( memcmp( pTempData, pOutData, dataLen ) != 0 )
		{
			VCR_Error( "VCR_GenericPlayback: data doesn't match on playback." );
		}
	}
	else
	{
		VCR_Read( pOutData, dataLen );
	}

	return dataLen;
}


int VCR_GenericPlayback( const char *pEventName, void *pOutData, int maxLen, bool bForceSameLen )
{
	return VCR_GenericPlaybackInternal( pEventName, pOutData, maxLen, bForceSameLen, false );
}


void VCR_GenericValue( const char *pEventName, void *pData, int maxLen )
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return;

	if ( !pEventName )
		pEventName = "";
	
	if ( g_VCRMode == VCR_Record )
		VCR_GenericRecord( pEventName, pData, maxLen );
	else if ( g_VCRMode == VCR_Playback )
		VCR_GenericPlaybackInternal( pEventName, pData, maxLen, true, false );
}


void VCR_GenericValueVerify( const tchar *pEventName, const void *pData, int maxLen )
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return;

	if ( !pEventName )
		pEventName = "";
	
	if ( g_VCRMode == VCR_Record )
		VCR_GenericRecord( pEventName, pData, maxLen );
	else if ( g_VCRMode == VCR_Playback )
		VCR_GenericPlaybackInternal( pEventName, (void*)pData, maxLen, true, true );
}


void WriteShortString( const char *pStr )
{
	int len = strlen( pStr ) + 1;
	if ( len >= 0xFFFF )
	{
		Error( "VCR_WriteShortString, string too long (%d characters).", len );
	}

	unsigned short twobytes = (unsigned short)len;
	VCR_WriteVal( twobytes );
	VCR_Write( pStr, len );
}


void ReadAndVerifyShortString( const char *pStr )
{
	int len = strlen( pStr ) + 1;

	unsigned short incomingSize;
	VCR_ReadVal( incomingSize );

	if ( incomingSize != len )
		VCR_Error( "ReadAndVerifyShortString (%s), lengths different.", pStr );

	static char *pTempData = 0;
	static int tempDataLen = 0;
	if ( tempDataLen < len )
	{
		delete [] pTempData;
		pTempData = new char[len];
		tempDataLen = len;
	}

	VCR_Read( pTempData, len );
	if ( memcmp( pTempData, pStr, len ) != 0 )
	{
		VCR_Error( "ReadAndVerifyShortString: strings different ('%s' vs '%s').", pStr, pTempData );
	}
}


void VCR_GenericRecordString( const char *pEventName, const char *pString )
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return;

	VCR_THREADSAFE;
	VCR_Event( VCREvent_GenericString );

	if ( g_VCRMode != VCR_Record )
		Error( "VCR_GenericRecordString( %s ): not recording a VCR file", pEventName );

	// Write the event name (or 255 if none).
	WriteShortString( pEventName );
	WriteShortString( pString );
}	


void VCR_GenericPlaybackString( const char *pEventName, const char *pString )
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() || g_VCRMode != VCR_Playback )
		Error( "VCR_GenericPlaybackString( %s ): not playing back a VCR file", pEventName );

	VCR_THREADSAFE;
	VCR_Event( VCREvent_GenericString );

	ReadAndVerifyShortString( pEventName );
	ReadAndVerifyShortString( pString );
}


void VCR_GenericString( const char *pEventName, const char *pString )
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return;

	if ( !pEventName )
		pEventName = "";

	if ( !pString )
		pString = "";

	if ( g_VCRMode == VCR_Record )
		VCR_GenericRecordString( pEventName, pString );
	else if ( g_VCRMode == VCR_Playback )
		VCR_GenericPlaybackString( pEventName, pString );
}


double VCR_GetPercentCompleted()
{
	if ( g_VCRMode == VCR_Playback )
	{
		return (double)g_CurFilePos / g_FileLen;
	}
	else
	{
		return 0;
	}
}

void* VCR_CreateThread( 
	void *lpThreadAttributes,
	unsigned long dwStackSize,
	void *lpStartAddress,
	void *lpParameter,
	unsigned long dwCreationFlags,
	unsigned long *lpThreadID )
{
	unsigned dwThreadID = 0;

	// Use _beginthreadex because it sets up C runtime
	// correctly, and is safer than _beginthread. See MSDN.

	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
	{
		if ( g_VCRMode == VCR_Disabled )
		{
			HANDLE hThread = (void *)_beginthreadex( 
				(LPSECURITY_ATTRIBUTES)lpThreadAttributes,
				dwStackSize,
				(unsigned (__stdcall *) (void *))lpStartAddress,
				lpParameter,
				dwCreationFlags,
				&dwThreadID );

			if ( lpThreadID )
				*lpThreadID = dwThreadID;

			return hThread;
		}
		else
		{
			Error( "VCR_CreateThread: VCR mode disabled in calling thread." );
		}
	}
	
	// We could make this work without too much pain.
	if ( GetCurrentThreadId() != g_VCRMainThreadID )
	{
		Error( "VCR_CreateThread called outside main thread." );
	}

	if ( g_nVCRThreads >= MAX_VCR_THREADS )
	{
		// This is easy to fix if we ever hit it.. just allow more threads.
		Error( "VCR_CreateThread: g_nVCRThreads >= MAX_VCR_THREADS." );
	}

	// Write out the VCR event saying this thread is being created.
	VCR_THREADSAFE;
	VCR_Event( VCREvent_CreateThread );

	// Create the thread.
	HANDLE hThread = (void*)_beginthreadex( 
		(LPSECURITY_ATTRIBUTES)lpThreadAttributes,
		dwStackSize,
		(unsigned (__stdcall *) (void *))lpStartAddress,
		lpParameter,
		dwCreationFlags | CREATE_SUSPENDED,
		&dwThreadID );

	if ( lpThreadID )
		*lpThreadID = dwThreadID;

	if ( !hThread )
	{
		// We don't handle this case in VCR mode (but we could pretty easily).
		if ( g_VCRMode == VCR_Playback || g_VCRMode == VCR_Record )
			Error( "VCR_CreateThread: CreateThread() failed." );

		return NULL;
	}

	// Register this thread so we can write its ID into future VCR events.
	int iNewThread = g_nVCRThreads++;
	g_pVCRThreads[iNewThread].m_ThreadID = dwThreadID;
	g_pVCRThreads[iNewThread].m_hWaitEvent = CreateEvent( NULL, false, false, NULL );
	g_pVCRThreads[iNewThread].m_bEnabled = true;

	// Now resume the thread.
	if ( !( dwCreationFlags & CREATE_SUSPENDED ) )
	{
		ResumeThread( hThread );
	}

	return hThread;
}


unsigned long VCR_WaitForSingleObject(
	void *handle,
	unsigned long dwMilliseconds )
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return Wrap_WaitForSingleObject( handle, dwMilliseconds );
		//Error( "VCR_WaitForSingleObject: VCR mode disabled in calling thread." );

	// We have to do the wait here BEFORE we acquire the VCR mutex, otherwise, we could freeze
	// the thread that's supposed to signal "handle".
	unsigned long ret = 0;
	if ( g_VCRMode == VCR_Record )
	{
		 ret = Wrap_WaitForSingleObject( handle, dwMilliseconds );
	}

	VCR_THREADSAFE;
	VCR_Event( VCREvent_WaitForSingleObject );

	char val = 1;
	if ( g_VCRMode == VCR_Record )
	{
		if ( ret == WAIT_ABANDONED )
			val = 2;
		else if ( ret == WAIT_TIMEOUT )
			val = 3;

		VCR_WriteVal( val );		
		return ret;
	}
	else
	{
		Assert( g_VCRMode == VCR_Playback );
		
		VCR_ReadVal( val );
		if ( val == 1 )
		{
			// Hack job.. let other threads start reading events now.. we're basically saying here that we're 
			// finished reading our VCR event. If we didn't pass the buck onto the next one, if the event hadn't
			// already been signalled, it might never get signalled.
			vcrThreadSafe.SignalNextEvent();

			// If it wrote 1, then we know that this call has to signal the object, so just wait until it gets signalled.
			ret = Wrap_WaitForSingleObject( handle, INFINITE );
			if ( ret == WAIT_ABANDONED || ret == WAIT_TIMEOUT )
			{
				Error( "VCR_WaitForSingleObject: got inconsistent value on playback." );
			}

			return ret;
		}
		else
		{
			// Return whatever the function returned while it was recording.
			return (val == 2) ? WAIT_ABANDONED : WAIT_TIMEOUT;
		}
	}
}

unsigned long VCR_WaitForMultipleObjects( uint32 nHandles, const void **pHandles, int bWaitAll, uint32 timeout )
{
	// Preamble.
	if ( !IsVCRModeEnabledForThisThread() )
		return Wrap_WaitForMultipleObjects( nHandles, pHandles, bWaitAll, timeout );

	// TODO:
	AssertMsg( 0, "Need to implement VCR_WaitForMultipleObjects" );
	return 0;
}

void VCR_EnterCriticalSection( void *pInputCS )
{
	CRITICAL_SECTION *pCS = (CRITICAL_SECTION*)pInputCS;

	if ( !IsVCRModeEnabledForThisThread() )
	{
		Wrap_EnterCriticalSection( pCS );
		return;
	}

	// While recording, let's get the critical section first.
	if ( g_VCRMode == VCR_Record )
	{
		 Wrap_EnterCriticalSection( pCS );
	}

	VCR_THREADSAFE;
	VCR_Event( VCREvent_EnterCriticalSection );

	if ( g_VCRMode == VCR_Playback )
	{
		// When playing back, we want to grab the CS -after- the event has been read out, because it means that
		// we're the only thread that is at this spot now. If we tried to grab the CS before calling VCR_Event,
		// then it might let the wrong thread have the CS on playback.
		Wrap_EnterCriticalSection( pCS );
	}
}


// ---------------------------------------------------------------------- //
// The global VCR interface.
// ---------------------------------------------------------------------- //

VCR_t g_VCR =
{
	VCR_Start,
	VCR_End,
	VCR_GetVCRTraceInterface,
	VCR_GetMode,
	VCR_SetEnabled,
	VCR_SyncToken,
	VCR_Hook_Sys_FloatTime,
	VCR_Hook_PeekMessage,
	VCR_Hook_RecordGameMsg,
	VCR_Hook_RecordEndGameMsg,
	VCR_Hook_PlaybackGameMsg,
	VCR_Hook_recvfrom,
	VCR_Hook_GetCursorPos,
	VCR_Hook_ScreenToClient,
	VCR_Hook_Cmd_Exec,
	VCR_Hook_GetCommandLine,
	VCR_Hook_RegOpenKeyEx,
	VCR_Hook_RegSetValueEx,
	VCR_Hook_RegQueryValueEx,
	VCR_Hook_RegCreateKeyEx,
	VCR_Hook_RegCloseKey,
	VCR_Hook_GetNumberOfConsoleInputEvents,
	VCR_Hook_ReadConsoleInput,
	VCR_Hook_LocalTime,
	VCR_Hook_GetKeyState,
	VCR_Hook_recv,
	VCR_Hook_send,
	VCR_GenericRecord,
	VCR_GenericPlayback,
	VCR_GenericValue,
	VCR_GetPercentCompleted,
	VCR_CreateThread,
	VCR_WaitForSingleObject,
	VCR_EnterCriticalSection,
	VCR_Hook_Time,
	VCR_GenericString,
	VCR_GenericValueVerify,
	VCR_WaitForMultipleObjects,
};

VCR_t *g_pVCR = &g_VCR;

#endif // NO_VCR