strmresid.h

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//----------------------------------------------------------------------------
// ObjectWindows
//
/// \file
/// Private helper for reading resource identifiers from persistent streams.
//----------------------------------------------------------------------------
 
#ifndef OWL_STRMRESID_H
#define OWL_STRMRESID_H
 
#include <owl/private/defs.h>
#if defined(BI_HAS_PRAGMA_ONCE)
# pragma once
#endif
 
#include <owl/defs.h>
#include <owl/wsyscls.h>
#include <memory>
#include <set>
 
#if defined(BI_MULTI_THREAD_RTL)
#include <owl/thread.h>
#endif
 
namespace owl {
 
//
// Takes ownership of a resource identifier just extracted from a persistent stream, and returns
// an equivalent identifier that does not need to be deallocated.
//
// The persistent stream extraction operator for TResId allocates a new string when the identifier
// is a string, leaving the caller responsible for deallocating it. Many members that store
// resource identifiers do not own the string (e.g. TWindow::Attr.AccelTable, TMenuDescr::Id),
// so here the string is moved into a process-lifetime pool instead, in which equal strings are
// shared. Hence, repeated reads of the same identifiers do not use any more memory. See bug #156.
//
inline auto InternStreamedResId_(TResId id) -> TResId
{
  if (!id.IsString()) return id;
  const auto s = std::unique_ptr<tchar[]>{const_cast<tchar*>(id.GetString())};
  static std::set<tstring> pool;
#if defined(BI_MULTI_THREAD_RTL)
  static TCriticalSection section;
  TCriticalSection::TLock lock{section};
#endif
  return TResId{pool.insert(tstring{s.get()}).first->c_str()};
}
 
} // OWL namespace
 
#endif  // OWL_STRMRESID_H