159 lines
4.8 KiB
C++
159 lines
4.8 KiB
C++
//+---------------------------------------------------------------------
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//
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// File: stgutils.hxx
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//
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// Contents: IStorage and IStream Helper functions
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//
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//----------------------------------------------------------------------
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#include "headers.hxx"
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#pragma hdrstop
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//+---------------------------------------------------------------
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//
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// Function: GetMonikerDisplayName
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//
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// Synopsis: Retrieves the display name of a moniker
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//
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// Arguments: [pmk] -- the moniker for which the display name is requested
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// [ppstr] -- the place where the display name is returned
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//
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// Returns: Success iff the display name could be retrieved
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//
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// Notes: The display name string is allocated using the task allocator
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// and should be freed by the same.
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//
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//----------------------------------------------------------------
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HRESULT
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GetMonikerDisplayName(LPMONIKER pmk, LPOLESTR FAR* ppstr)
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{
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HRESULT r;
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LPBC pbc;
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if (OK(r = CreateBindCtx(0, &pbc)))
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{
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r = pmk->GetDisplayName(pbc, NULL, ppstr);
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pbc->Release();
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}
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return r;
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}
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//+---------------------------------------------------------------
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//
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// Function: CreateStorageOnHGlobal
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//
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// Synopsis: Creates an IStorage on a global memory handle
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//
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// Arguments: [hgbl] -- memory handle to create storage on
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// [ppStg] -- where the storage is returned
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//
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// Returns: Success iff the storage could be successfully created
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// on the memory handle.
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//
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// Notes: This helper function combines CreateILockBytesOnHGlobal
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// and StgCreateDocfileOnILockBytes. hgbl may be NULL in
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// which case a global memory handle will be automatically
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// allocated.
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//
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//----------------------------------------------------------------
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HRESULT
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CreateStorageOnHGlobal(HGLOBAL hgbl, LPSTORAGE FAR* ppStg)
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{
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HRESULT r;
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LPLOCKBYTES pLockBytes;
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if (OK(r = CreateILockBytesOnHGlobal(hgbl, TRUE, &pLockBytes)))
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{
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//REVIEW: should be use STGM_DELETEONRELEASE when hgbl == NULL?
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r = StgCreateDocfileOnILockBytes(pLockBytes,
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STGM_CREATE|STGM_READWRITE|STGM_SHARE_EXCLUSIVE, 0, ppStg);
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pLockBytes->Release();
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}
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return r;
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}
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//+---------------------------------------------------------------
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//
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// Function: ConvertToMemoryStream
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//
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// Synopsis: Takes a stream and produces an equivalent stream
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// stored in memory for faster individual reads
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//
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// Arguments: [pStrmFrom] -- the stream to convert
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//
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// Returns: An equivalent stream
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//
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// Notes: Any failure in creating the memory stream will result in
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// the original stream, pStrmFrom, being returned.
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// Hence the caller should assume the stream passed in has
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// been released and should release the stream returned
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// after it has finished using it.
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//
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//----------------------------------------------------------------
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LPSTREAM
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ConvertToMemoryStream(LPSTREAM pStrmFrom)
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{
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//REVIEW: perhaps we should use the IStream::CopyTo function
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// instead of doing the read manually!
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HRESULT r;
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LPSTREAM pStrm = NULL;
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STATSTG statstg;
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if (OK(r = pStrmFrom->Stat(&statstg, STATFLAG_NONAME)))
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{
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if (statstg.cbSize.HighPart != 0)
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{
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DOUT(TEXT("o2base/stdils/ConvertToMemoryStream E_FAIL\r\n"));
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r = E_FAIL;
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}
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else
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{
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HGLOBAL hgbl = GlobalAlloc(GMEM_SHARE, statstg.cbSize.LowPart);
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if (hgbl == NULL)
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{
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DOUT(TEXT("o2base/stgutils/ConvertToMemoryStream failed\r\n"));
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r = E_OUTOFMEMORY;
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}
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else
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{
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LPVOID pv = GlobalLock(hgbl);
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if (pv == NULL)
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{
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DOUT(TEXT("o2base/stdils/ConvertToMemoryStream E_FAIL(2)\r\n"));
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r = E_FAIL;
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}
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else
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{
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r = pStrmFrom->Read(pv, statstg.cbSize.LowPart, NULL);
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GlobalUnlock(hgbl);
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if (OK(r))
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{
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if (OK(r = CreateStreamOnHGlobal(hgbl, TRUE, &pStrm)))
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{
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pStrm->SetSize(statstg.cbSize);
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pStrmFrom->Release();
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}
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else
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{
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DOUT(TEXT("o2base/stdils/ConvertToMemoryStream CreateStreamOnHGlobal Failed!\r\n"));
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}
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}
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}
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if (!OK(r))
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{
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GlobalFree(hgbl);
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}
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}
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}
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}
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if (!OK(r))
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{
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pStrm = pStrmFrom;
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}
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return pStrm;
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}
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