68 lines
1.3 KiB
C++
68 lines
1.3 KiB
C++
/*
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* A T O M C A C H E . C P P
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*
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* atom cache
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*
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* Copyright 1986-1997 Microsoft Corporation, All Rights Reserved
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*/
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#include "_xmllib.h"
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// CXAtomCache::GetCachedAtom ------------------------------------------------
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//
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SCODE
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CXAtomCache::ScGetCachedAtom (CRCWszN& key, LPCWSTR* pwszAtom)
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{
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LPCWSTR wszCommitted;
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LPCWSTR* pwsz;
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SCODE sc = S_OK;
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// First look to see if it is already there.
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//
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{
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CSynchronizedReadBlock srb(m_lock);
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pwsz = m_cache.Lookup (key);
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}
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// If it wasn't there, do our best to add it
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//
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if (NULL == pwsz)
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{
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CSynchronizedWriteBlock swb(m_lock);
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// There is a small window where it could
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// have shown up, so do a second quick peek
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//
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pwsz = m_cache.Lookup (key);
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if (NULL == pwsz)
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{
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// Commit the string to perm. storage
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//
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wszCommitted = m_csb.Append(key.m_cch*sizeof(WCHAR), key.m_pwsz);
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if (NULL == wszCommitted)
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{
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sc = E_OUTOFMEMORY;
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goto ret;
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}
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// Add the atom to the cache, but before it
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// gets added, swap out the key's string pointer
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// to the committed version.
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//
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key.m_pwsz = wszCommitted;
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m_cache.FAdd (key, wszCommitted);
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// Setup for the return
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//
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pwsz = &wszCommitted;
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}
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}
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Assert (pwsz);
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Assert (pwszAtom);
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*pwszAtom = *pwsz;
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ret:
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return sc;
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}
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