rainmeter-studio/Plugins/PluginPerfMon/PerfSnap.cpp

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//============================================================================
// File: PERFSNAP.CPP
// Author: Matt Pietrek
// From: Microsoft Systems Journal, "Under the Hood", March 1996
//============================================================================
#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN
#endif
#include <windows.h>
#include <winperf.h>
#include <stdlib.h>
#include <tchar.h>
#pragma hdrstop
#include "titledb.h"
#include "perfsnap.h"
#include "makeptr.h"
PBYTE CPerfSnapshot::c_pBuffer = nullptr;
DWORD CPerfSnapshot::c_cbBufferSize = 0;
CPerfSnapshot::CPerfSnapshot(
CPerfTitleDatabase * pCounterTitles )
{
m_pPerfDataHeader = 0;
m_pCounterTitles = pCounterTitles;
}
CPerfSnapshot::~CPerfSnapshot( void )
{
DisposeSnapshot();
}
BOOL
CPerfSnapshot::TakeSnapshot( PCTSTR pszSnapshotItems )
{
DisposeSnapshot(); // Clear out any current snapshot
// Convert the input string (e.g., "Process") into the form required
// by the HKEY_PERFORMANCE_DATA key (e.g., "232")
TCHAR szConvertedItemNames[ 256 ];
if ( !ConvertSnapshotItemName( pszSnapshotItems, szConvertedItemNames,
sizeof(szConvertedItemNames) ) )
return FALSE;
DWORD cbAllocSize = 0;
LONG retValue;
while ( 1 ) // Loop until we get the data, or we fail unexpectedly
{
retValue = RegQueryValueEx( HKEY_PERFORMANCE_DATA,
szConvertedItemNames, 0, 0,
c_pBuffer, &c_cbBufferSize );
if ( retValue == ERROR_SUCCESS ) // We apparently got the snapshot
{
m_pPerfDataHeader = (PPERF_DATA_BLOCK)c_pBuffer;
// Verify that the signature is a unicode "PERF"
if ( memcmp( m_pPerfDataHeader->Signature, L"PERF", 8 ) )
break;
return TRUE;
}
else if ( retValue != ERROR_MORE_DATA ) // Anything other failure
break; // code means something
// bad happened, so bail out.
// If we get here, our buffer wasn't big enough. Delete it and
// try again with a bigger buffer.
delete [] c_pBuffer;
// The new buffer size will be 4096 bytes bigger than the larger
// of: 1) The previous allocation size, or 2) The size that the
// RegQueryValueEx call said was necessary.
if ( c_cbBufferSize > cbAllocSize )
cbAllocSize = c_cbBufferSize + 4096;
else
cbAllocSize += 4096;
// Allocate a new, larger buffer in preparation to try again.
c_pBuffer = new BYTE[ cbAllocSize ];
if ( !c_pBuffer )
break;
c_cbBufferSize = cbAllocSize;
}
// If we get here, the RegQueryValueEx failed unexpectedly.
return FALSE;
}
void
CPerfSnapshot::DisposeSnapshot( void )
{
m_pPerfDataHeader = 0;
}
void
CPerfSnapshot::CleanUp( void )
{
delete [] c_pBuffer;
c_pBuffer = 0;
c_cbBufferSize = 0;
}
DWORD
CPerfSnapshot::GetNumObjectTypes( void )
{
return m_pPerfDataHeader ? m_pPerfDataHeader->NumObjectTypes: 0;
}
BOOL
CPerfSnapshot::GetSystemName( PTSTR pszSystemName, DWORD nSize )
{
if ( !m_pPerfDataHeader ) // If no snapshot data, bail out.
return FALSE;
// Make sure the input buffer size is big enough
if ( nSize < m_pPerfDataHeader->SystemNameLength )
return FALSE;
// Make a unicode string point to the system name string
// that's stored in the PERF_DATA_BLOCK
LPWSTR lpwszName = MakePtr( LPWSTR, m_pPerfDataHeader,
m_pPerfDataHeader->SystemNameOffset );
#ifdef UNICODE // Copy the PERF_DATA_BLOCK string to the input buffer
lstrcpy( pszSystemName, lpwszName );
#else
wcstombs( pszSystemName, lpwszName, nSize );
#endif
return TRUE;
}
PVOID
CPerfSnapshot::GetPostHeaderPointer( void )
{
// Returns a header to the first byte following the PERF_DATA_BLOCK
// (including the variable length system name string at the end)
return m_pPerfDataHeader ?
MakePtr(PVOID, m_pPerfDataHeader,m_pPerfDataHeader->HeaderLength)
: 0;
}
BOOL
CPerfSnapshot::ConvertSnapshotItemName( PCTSTR pszIn,
PTSTR pszOut, DWORD nSize )
{
if ( IsBadStringPtr( pszIn, 0xFFFFFFFF ) )
return FALSE;
DWORD objectID = m_pCounterTitles->GetIndexFromTitleString(pszIn);
if ( objectID )
pszOut += wsprintf( pszOut, TEXT("%u "), objectID );
else
pszOut += wsprintf( pszOut, TEXT("%s "), pszIn );
return TRUE;
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}