Samples/multimedia/directshow/baseclasses/perflog.cpp

//------------------------------------------------------------------------------
// File: perflog.cpp
//
// Desc: Macros for DirectShow performance logging.
//
// Copyright (c) 1992-2001 Microsoft Corporation.  All rights reserved.
//------------------------------------------------------------------------------

#pragma warning (disable:4201)

#include <streams.h>
#include <windows.h>
#include <tchar.h>
#include <winperf.h>
#include <wmistr.h>
#include <evntrace.h>
#include <strsafe.h>
#include "perflog.h"

//
// Local function prototypes.
//

ULONG
WINAPI
PerflogCallback (
    WMIDPREQUESTCODE RequestCode,
    __in PVOID Context,
    __out ULONG* BufferSize,
    __in PVOID Buffer
    );

//
// Event tracing function pointers.
// We have to do this to run on down-level platforms.
//

#ifdef UNICODE

ULONG
(__stdcall * _RegisterTraceGuids) (
    __in IN WMIDPREQUEST RequestAddress,
    __in IN PVOID RequestContext,
    IN LPCGUID ControlGuid,
    IN ULONG GuidCount,
    __in IN PTRACE_GUID_REGISTRATION TraceGuidReg,
    IN LPCWSTR MofImagePath,
    IN LPCWSTR MofResourceName,
    OUT PTRACEHANDLE RegistrationHandle
    );

#define REGISTERTRACEGUIDS_NAME "RegisterTraceGuidsW"

#else

ULONG
(__stdcall * _RegisterTraceGuids) (
    __in IN WMIDPREQUEST RequestAddress,
    __in IN PVOID RequestContext,
    IN LPCGUID ControlGuid,
    IN ULONG GuidCount,
    __in IN PTRACE_GUID_REGISTRATION TraceGuidReg,
    IN LPCSTR MofImagePath,
    IN LPCSTR MofResourceName,
    __out OUT PTRACEHANDLE RegistrationHandle
    );

#define REGISTERTRACEGUIDS_NAME "RegisterTraceGuidsA"

#endif

ULONG
(__stdcall * _UnregisterTraceGuids) (
    TRACEHANDLE RegistrationHandle
    );

TRACEHANDLE
(__stdcall * _GetTraceLoggerHandle) (
    __in PVOID Buffer
    );

UCHAR
(__stdcall * _GetTraceEnableLevel) (
    TRACEHANDLE TraceHandle
    );

ULONG
(__stdcall * _GetTraceEnableFlags) (
    TRACEHANDLE TraceHandle
    );

ULONG
(__stdcall * _TraceEvent) (
    TRACEHANDLE TraceHandle,
    __in PEVENT_TRACE_HEADER EventTrace
    );

HINSTANCE _Advapi32;

//
// Global variables.
//

BOOL EventTracingAvailable=FALSE;
ULONG PerflogEnableFlags;
UCHAR PerflogEnableLevel;
ULONG PerflogModuleLevel = 0;
void (*OnStateChanged)(void);
TRACEHANDLE PerflogTraceHandle=NULL;
TRACEHANDLE PerflogRegHandle;

// The Win32 wsprintf() function writes a maximum of 1024 characters to it's output buffer.
// See the documentation for wsprintf()'s lpOut parameter for more information.
const INT iDEBUGINFO = 1024; // Used to format strings

//
// This routine initializes performance logging.
// It should be called from DllMain().
//


VOID
PerflogReadModuleLevel(
    HINSTANCE hInstance
    )
{
    LONG lReturn;                   // Create key return value
    TCHAR szInfo[iDEBUGINFO];       // Constructs key names
    TCHAR szFullName[iDEBUGINFO];   // Load the full path and module name
    HKEY hModuleKey;                // Module key handle
    LPTSTR pName;                   // Searches from the end for a backslash
    DWORD dwKeySize, dwKeyType, dwKeyValue;

    DWORD dwSize = GetModuleFileName(
        (hInstance ? hInstance : GetModuleHandle( NULL )),
        szFullName,
        iDEBUGINFO );

    if (0 == dwSize || iDEBUGINFO == dwSize) {
        return;
    }

    pName = _tcsrchr(szFullName,'\\');
    if (pName == NULL) {
        pName = szFullName;
    } else {
        pName++;
    }

    /* Construct the base key name */
    (void)StringCchPrintf(szInfo,NUMELMS(szInfo),TEXT("SOFTWARE\\Debug\\%s"),pName);

    /* Open the key for this module */
    lReturn =
        RegOpenKeyEx(
            HKEY_LOCAL_MACHINE,   // Handle of an open key
            szInfo,               // Address of subkey name
            (DWORD) 0,            // Reserved value
            KEY_QUERY_VALUE,      // Desired security access
            &hModuleKey );        // Opened handle buffer

    if (lReturn != ERROR_SUCCESS) {
        return;
    }

    dwKeySize = sizeof(DWORD);
    lReturn = RegQueryValueEx(
        hModuleKey,                 // Handle to an open key
        TEXT("PERFLOG"),
        NULL,                       // Reserved field
        &dwKeyType,                 // Returns the field type
        (LPBYTE) &dwKeyValue,       // Returns the field's value
        &dwKeySize );               // Number of bytes transferred

    if ((lReturn == ERROR_SUCCESS) && (dwKeyType == REG_DWORD))
    {
        PerflogModuleLevel = dwKeyValue;
    }

    RegCloseKey(hModuleKey);
}

BOOL PerflogInitIfEnabled(
    IN HINSTANCE hInstance,
    __in IN PPERFLOG_LOGGING_PARAMS LogParams
    )
{
    PerflogReadModuleLevel( hInstance );
    if (PerflogModuleLevel)
    {
        return PerflogInitialize( LogParams );
    }
    else
    {
        return FALSE;
    }
}

BOOL
PerflogInitialize (
    __in IN PPERFLOG_LOGGING_PARAMS LogParams
    )
{
    ULONG status;

    //
    // If we're running on a recent-enough platform, this will get
    // pointers to the event tracing routines.
    //

    _Advapi32 = GetModuleHandle (_T("ADVAPI32.DLL"));
    if (_Advapi32 == NULL) {
        return FALSE;
    }

    *((FARPROC*) &_RegisterTraceGuids) = GetProcAddress (_Advapi32, REGISTERTRACEGUIDS_NAME);
    *((FARPROC*) &_UnregisterTraceGuids) = GetProcAddress (_Advapi32, "UnregisterTraceGuids");
    *((FARPROC*) &_GetTraceLoggerHandle) = GetProcAddress (_Advapi32, "GetTraceLoggerHandle");
    *((FARPROC*) &_GetTraceEnableLevel) = GetProcAddress (_Advapi32, "GetTraceEnableLevel");
    *((FARPROC*) &_GetTraceEnableFlags) = GetProcAddress (_Advapi32, "GetTraceEnableFlags");
    *((FARPROC*) &_TraceEvent) = GetProcAddress (_Advapi32, "TraceEvent");

    if (_RegisterTraceGuids == NULL ||
        _UnregisterTraceGuids == NULL ||
        _GetTraceEnableLevel == NULL ||
        _GetTraceEnableFlags == NULL ||
        _TraceEvent == NULL) {

        return FALSE;
    }

    EventTracingAvailable = TRUE;

    OnStateChanged = LogParams->OnStateChanged;

    //
    // Register our GUIDs.
    //

    status = _RegisterTraceGuids (PerflogCallback,
                                  LogParams,
                                  &LogParams->ControlGuid,
                                  LogParams->NumberOfTraceGuids,
                                  LogParams->TraceGuids,
                                  NULL,
                                  NULL,
                                  &PerflogRegHandle);

    return (status == ERROR_SUCCESS);
}

//
// This routine shuts down performance logging.
//

VOID
PerflogShutdown (
    VOID
    )
{
    if (!EventTracingAvailable) {
        return;
    }

    _UnregisterTraceGuids (PerflogRegHandle);
    PerflogRegHandle = NULL;
    PerflogTraceHandle = NULL;
}

//
// Event tracing callback routine.
// It's called when controllers call event tracing control functions.
//

ULONG
WINAPI
PerflogCallback (
    WMIDPREQUESTCODE RequestCode,
    __in PVOID Context,
    __out ULONG* BufferSize,
    __in PVOID Buffer
    )
{
    ULONG status;

    UNREFERENCED_PARAMETER (Context);

    ASSERT (EventTracingAvailable);

    status = ERROR_SUCCESS;

    switch (RequestCode) {

    case WMI_ENABLE_EVENTS:
        PerflogTraceHandle = _GetTraceLoggerHandle (Buffer);
        PerflogEnableFlags = _GetTraceEnableFlags (PerflogTraceHandle);
        PerflogEnableLevel = _GetTraceEnableLevel (PerflogTraceHandle);
        break;

    case WMI_DISABLE_EVENTS:
        PerflogTraceHandle = NULL;
        PerflogEnableFlags = 0;
        PerflogEnableLevel = 0;
        break;

    default:
        status = ERROR_INVALID_PARAMETER;
    }

    if (OnStateChanged != NULL) {
        OnStateChanged();
    }

    *BufferSize = 0;
    return status;
}

//
// Logging routine.
//

VOID
PerflogTraceEvent (
    __in PEVENT_TRACE_HEADER Event
    )
{
    if (!EventTracingAvailable) {
        return;
    }

    _TraceEvent (PerflogTraceHandle, Event);
}

VOID
PerflogTraceEventLevel(
    ULONG Level,
    __in PEVENT_TRACE_HEADER Event
    )
{
    if ((!EventTracingAvailable) || (Level <= PerflogModuleLevel)) {
        return;
    }

    _TraceEvent (PerflogTraceHandle, Event);
}