185 lines
4.8 KiB
C++
185 lines
4.8 KiB
C++
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// Copyright (c) 1996-1999 Microsoft Corporation
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//+============================================================================
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//
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// volcache.cxx
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//
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// Implementation for CVolumeLocationCache. This class is used by trkwks
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// to keep a cache of volid->mcid mappings.
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//
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//+============================================================================
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#include "pch.cxx"
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#pragma hdrstop
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#include "trkwks.hxx"
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//+----------------------------------------------------------------------------
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//
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// CVolumeLocationCache::Initialize
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//
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// Init the critsec and set the lifetime value.
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//
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//+----------------------------------------------------------------------------
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void
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CVolumeLocationCache::Initialize( DWORD dwEntryLifetimeSeconds )
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{
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_cs.Initialize();
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_fInitialized = TRUE;
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_cVols = 0;
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_cftEntryLifetime = 0;
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_cftEntryLifetime.IncrementSeconds( dwEntryLifetimeSeconds );
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}
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//+----------------------------------------------------------------------------
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//
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// CVolumeLocationCache::UnInitialize
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//
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// Free the critsec.
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//
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//+----------------------------------------------------------------------------
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void
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CVolumeLocationCache::UnInitialize()
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{
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if (_fInitialized)
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{
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_fInitialized = FALSE;
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_cs.UnInitialize();
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}
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}
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//+----------------------------------------------------------------------------
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//
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// CVolumeLocationCache::_FindVolume
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//
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// Search the cache for a volid. If it's found, return it's index in the
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// cache array.
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//
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//+----------------------------------------------------------------------------
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int
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CVolumeLocationCache::_FindVolume(const CVolumeId & volid)
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{
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for (int i=0; i<_cVols; i++)
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{
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if (_vl[i].volid == volid)
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{
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return(i);
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}
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}
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return(-1);
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}
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//+----------------------------------------------------------------------------
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//
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// CVolumeLocationCache::FindVolume
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//
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// search the cache for a volid. If found, return the machine ID it was
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// last known to be on, and a bool indicating if this entry in the cache
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// is old or new. If it's old and doesn't work, the caller shouldn't
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// trust the cache. If it's new and doesn't work, the caller shouldn't
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// bother the DC trying to find it.
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//
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//+----------------------------------------------------------------------------
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BOOL
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CVolumeLocationCache::FindVolume(const CVolumeId & volid, CMachineId * pmcid, BOOL *pfRecentEntry )
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{
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int i;
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_cs.Enter();
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i=_FindVolume(volid );
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if (i != -1)
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{
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// We found the volume. Load the data.
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CFILETIME cftNow;
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*pmcid=_vl[i].mcid;
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*pfRecentEntry = ( (cftNow - _vl[i].cft) <= _cftEntryLifetime );
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}
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_cs.Leave();
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return(i != -1);
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}
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//+----------------------------------------------------------------------------
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//
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// CVolumeLocationCache::AddVolume
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//
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// Add a volid->mcid mapping to the cache. The entry in the cache is
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// timestamped so we know how trustworthy it is. If the entry is already
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// in the cache, we just update the timestamp. In either case, this entry
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// will be at the front of the array.
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//
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//+----------------------------------------------------------------------------
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void
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CVolumeLocationCache::AddVolume(const CVolumeId & volid, const CMachineId & mcid)
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{
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int i;
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if( CVolumeId() == volid )
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return;
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_cs.Enter();
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i = _FindVolume(volid);
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if (i == -1)
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{
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// This volid isn't already in the cache. Shift back the existing
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// entries so that this entry can be in front.
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BOOL fFull = _cVols >= MAX_CACHED_VOLUME_LOCATIONS;
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memcpy(&_vl[1], &_vl[0], sizeof(VolumeLocation)*(fFull ? _cVols-1 : _cVols));
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if (!fFull)
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{
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_cVols++;
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}
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}
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else
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{
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// Move the prior part of the array back, overwriting
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// the this entry. That way we can put this entry
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// at the front.
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memcpy(&_vl[1], &_vl[0], sizeof(VolumeLocation)*i);
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}
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// Put this entry at the front of the array.
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_vl[0].volid = volid;
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_vl[0].mcid = mcid;
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_vl[0].cft = CFILETIME();
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#if DBG
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for (i=0; i<_cVols; i++)
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{
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TrkLog((TRKDBG_VOLCACHE,
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TEXT("%02d: %s -> %s") MCID_BYTE_FORMAT_STRING,
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i,
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(const TCHAR*)CDebugString(_vl[i].volid),
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(const TCHAR*)CDebugString(_vl[i].mcid),
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((BYTE*)&(_vl[i].mcid))[0], ((BYTE*)&(_vl[i].mcid))[1], ((BYTE*)&(_vl[i].mcid))[2], ((BYTE*)&(_vl[i].mcid))[3],
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((BYTE*)&(_vl[i].mcid))[4], ((BYTE*)&(_vl[i].mcid))[5], ((BYTE*)&(_vl[i].mcid))[6], ((BYTE*)&(_vl[i].mcid))[7],
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((BYTE*)&(_vl[i].mcid))[8], ((BYTE*)&(_vl[i].mcid))[9], ((BYTE*)&(_vl[i].mcid))[10], ((BYTE*)&(_vl[i].mcid))[11],
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((BYTE*)&(_vl[i].mcid))[12], ((BYTE*)&(_vl[i].mcid))[13], ((BYTE*)&(_vl[i].mcid))[14], ((BYTE*)&(_vl[i].mcid))[15] ));
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}
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#endif
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_cs.Leave();
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}
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