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#ifndef COMSTRM_H
#define COMSTRM_H
//
// JonN 12/01/99
// 384722: compmgmt: GetDataHere is not returning an error
// if buffer is too small
// The callers routinely assume that if stream_ptr is initialized
// using a STGMEDIUM with TYMED_GLOBAL, that STGMEDIUM.hGlobal will
// be kept up to date with each Write(). This is not strictly true
// of a normal IStream, but we will build in this behavior in order
// to avoid changing too much client code. However, since GetDataHere
// (MSDN) specifies that the HGLOBAL should not be changed, we return
// STG_E_MEDIUMFULL if it changes; but we do still replace the HGLOBAL,
// since the old one is implicitly freed and the new one needs to be freed.
//
#ifndef COMPTRS_H
#include <comptrs.h>
#endif
namespace microsoft {namespace com {
class stream_ptr { // Construction
public: stream_ptr() throw() // Sets the stream to NULL
: m_pStream() , m_pWritebackHGlobal( NULL ) , m_hgOriginalHGlobal( NULL ) { }
public: explicit stream_ptr(const stream_ptr& pStream) throw() : m_pStream() , m_pWritebackHGlobal( NULL ) , m_hgOriginalHGlobal( NULL ) { Initialize(pStream.m_pStream); }
public: explicit stream_ptr(IStream* pStream) throw() // Saves the stream
: m_pStream() , m_pWritebackHGlobal( NULL ) , m_hgOriginalHGlobal( NULL ) { Initialize(pStream); }
//REVIEW: add template constructors
public: explicit stream_ptr(HGLOBAL global) throw() // Creates a stream on top of the global
: m_pStream() , m_pWritebackHGlobal( NULL ) , m_hgOriginalHGlobal( NULL ) { Initialize(global); }
public: explicit stream_ptr(LPCOLESTR filename) throw() // Creates a stream on top of the specified file
: m_pStream() , m_pWritebackHGlobal( NULL ) , m_hgOriginalHGlobal( NULL ) { Initialize(filename); }
public: explicit stream_ptr(STGMEDIUM& stgMedium) throw() // Saves the provided stream.
: m_pStream() , m_pWritebackHGlobal( NULL ) , m_hgOriginalHGlobal( NULL ) { Initialize(stgMedium); }
public: explicit stream_ptr(STGMEDIUM* pStgMedium) throw() // Saves the provided stream.
: m_pStream() , m_pWritebackHGlobal( NULL ) , m_hgOriginalHGlobal( NULL ) { if (pStgMedium) Initialize(*pStgMedium); } //REVIEW: Add Create and Open functions
//REVIEW: Add all of the assignment operators, cast operators, attach, detach, ->, *, etc.
public: operator IStream*() const throw() { //REVIEW: trace on null would be helpful
return m_pStream; }
public: IStream* operator->() const throw() { //REVIEW: trace on null would be helpful
return m_pStream; }
public: IStream& operator*() const throw() { //REVIEW: trace on null would be helpful
return *m_pStream; }
// Write interfaces
public: HRESULT Write( const void* pBuffer, unsigned long writeCount, unsigned long& written) throw() // Write the data contained in the buffer
{ if (m_pStream == NULL) return E_FAIL; //REVIEW: correct failure code?
HRESULT hr = m_pStream->Write(pBuffer, writeCount, &written); if (SUCCEEDED(hr) && NULL != m_pWritebackHGlobal) { HGLOBAL hgNew = NULL; hr = GetHGlobalFromStream(m_pStream, &hgNew); if (SUCCEEDED(hr)) { if (NULL == m_hgOriginalHGlobal) *m_pWritebackHGlobal = hgNew; else if (m_hgOriginalHGlobal != hgNew) { //
// When this occurs, the old HGLOBAL has already been freed
//
*m_pWritebackHGlobal = hgNew; hr = STG_E_MEDIUMFULL; } } } return hr; }
public: HRESULT Write(const void* pBuffer, unsigned long writeCount) throw() { unsigned long written = 0; HRESULT hr = Write(pBuffer, writeCount, written); // 2002/02/15-JonN Security push: do not ignore written!=writeCount
if (SUCCEEDED(hr) && written != writeCount) hr = STG_E_MEDIUMFULL; return hr; }
public: HRESULT Write(const wchar_t* string) throw() { // 2002/02/15-JonN pointer check
if (IsBadStringPtrW(string,(UINT_PTR)-1)) { ASSERT(FALSE); return E_POINTER; } unsigned long len=(unsigned long)(wcslen(string)+1); return Write(string, len*sizeof(wchar_t), len); }
public: HRESULT Write(const char* string) throw() { // 2002/02/15-JonN pointer check
if (IsBadStringPtrA(string,(UINT_PTR)-1)) { ASSERT(FALSE); return E_POINTER; } unsigned long len=(unsigned long)(strlen(string)+1); return Write(string, len, len); } //REVIEW: Read interfaces
//REVIEW: Seek
//REVIEW: Stat - broken out
// Initialization. May be used by derived classes to setup the stream for
// different types of storage mediums. These functions are all re-entrant,
// and may be called at any time. They perform all of the appropriate
// clean up and releasing of any resources in previous use.
protected: void Initialize(HGLOBAL hg) throw() { //REVIEW: make re-entrant and bullet proof
HRESULT const hr = CreateStreamOnHGlobal(hg, FALSE, &m_pStream); ASSERT(SUCCEEDED(hr)); }
protected: void Initialize(IStream* pStream) throw() { //REVIEW: make re-entrant and bullet proof
m_pStream = pStream; }
protected: void Initialize(LPCOLESTR filename) throw() { UNREFERENCED_PARAMETER (filename); //REVIEW: make re-entrant and bullet proof
#if 0 //REVIEW: need to create FileStream before this can be enabled
if (!filename || !*filename) return false;
cip<FileStream> fs = new CComObject<FileStream>; if (!fs) return false;
HRESULT hr = fs->Open(filename); if (FAILED(hr)) return false;
m_pStream = fs; return true; #endif // 0
}
protected: void Initialize(STGMEDIUM& storage) throw() // Initializes the read/write functions based on the type of storage
// medium. If there is a problem, the reader/writer is not set.
{ //REVIEW: make re-entrant and bullet proof
switch (storage.tymed) { case TYMED_HGLOBAL: Initialize(storage.hGlobal); m_hgOriginalHGlobal = storage.hGlobal; m_pWritebackHGlobal = &(storage.hGlobal); return;
case TYMED_FILE: Initialize(storage.lpszFileName); return;
case TYMED_ISTREAM: Initialize(storage.pstm); return; } }
// Implementation
private: IStreamCIP m_pStream; // This stream is created and used when the TYMED type is HGLOBAL.
//
// JonN 12/01/99 384722: see comments at top of file
//
HGLOBAL m_hgOriginalHGlobal; HGLOBAL* m_pWritebackHGlobal;
}; // class streamptr
} // namespace com
} // namespace microsoft
#ifndef MICROSOFT_NAMESPACE_ON
using namespace microsoft;#ifndef COM_NAMESPACE_ON
using namespace com;#endif // COM_NAMESPACE_ON
#endif // MICROSOFT_NAMESPACE_ON
#endif // COMSTRM_H
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