macssh/GUSI/include/GUSISpecific.h

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7.6 KiB
C++
Executable File

// %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
// % Project : GUSI - Grand Unified Socket Interface
// % File : GUSISpecific.nw - Thread specific variables
// % Author : Matthias Neeracher
// % Language : C++
// %
// % $Log$
// % Revision 1.1.1.1 2001/03/03 21:50:14 chombier
// % Initial import
// %
// % Revision 1.9 2000/10/16 04:11:21 neeri
// % Plug memory leak
// %
// % Revision 1.8 2000/03/15 07:22:07 neeri
// % Enforce alignment choices
// %
// % Revision 1.7 1999/08/26 05:45:10 neeri
// % Fixes for literate edition of source code
// %
// % Revision 1.6 1999/05/30 03:09:31 neeri
// % Added support for MPW compilers
// %
// % Revision 1.5 1999/04/29 04:58:20 neeri
// % Fix key destruction bug
// %
// % Revision 1.4 1999/03/17 09:05:13 neeri
// % Added GUSITimer, expanded docs
// %
// % Revision 1.3 1998/10/11 16:45:25 neeri
// % Ready to release 2.0a2
// %
// % Revision 1.2 1998/08/01 21:32:11 neeri
// % About ready for 2.0a1
// %
// % Revision 1.1 1998/01/25 21:02:52 neeri
// % Engine implemented, except for signals & scheduling
// %
// %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
//
// \chapter{Thread Specific Variables}
//
// It is often useful to have variables which maintain a different value
// for each process. The [[GUSISpecific]] class implements such a mechanism
// in a way that is easily mappable to pthreads.
//
//
// <GUSISpecific.h>=
#ifndef _GUSISpecific_
#define _GUSISpecific_
#ifndef GUSI_SOURCE
typedef struct GUSISpecific GUSISpecific;
#else
#include <Types.h>
#include <ConditionalMacros.h>
#if PRAGMA_STRUCT_ALIGN
#pragma options align=native
#endif
// \section{Definition of Thread Specific Variables}
//
// A [[GUSISpecific]] instance contains a variable ID and a per-process
// destructor.
//
// <Definition of class [[GUSISpecific]]>=
extern "C" {
typedef void (*GUSISpecificDestructor)(void *);
}
class GUSISpecific {
friend class GUSISpecificTable;
public:
GUSISpecific(GUSISpecificDestructor destructor = nil);
~GUSISpecific();
void Destruct(void * data);
private:
GUSISpecificDestructor fDestructor;
unsigned fID;
static unsigned sNextID;
};
// A [[GUSIContext]] contains a [[GUSISpecificTable]] storing the values of all
// thread specific variables defined for this thread.
//
// <Definition of class [[GUSISpecificTable]]>=
class GUSISpecificTable {
friend class GUSISpecific;
public:
GUSISpecificTable();
~GUSISpecificTable();
void * GetSpecific(const GUSISpecific * key) const;
void SetSpecific(const GUSISpecific * key, void * value);
void DeleteSpecific(const GUSISpecific * key);
private:
static void Register(GUSISpecific * key);
static void Destruct(GUSISpecific * key);
// We store a [[GUSISpecificTable]] as a contiguous range of IDs.
//
// <Privatissima of [[GUSISpecificTable]]>=
void *** fValues;
unsigned fAlloc;
bool Valid(const GUSISpecific * key) const;
// All keys are registered in a global table.
//
// <Privatissima of [[GUSISpecificTable]]>=
static GUSISpecific *** sKeys;
static unsigned sKeyAlloc;
};
// To simplify having a particular variable assume a different instance in every
// thread, we define the [[GUSISpecificData]] template.
//
// <Definition of template [[GUSISpecificData]]>=
template <class T, GUSISpecificDestructor D>
class GUSISpecificData {
public:
GUSISpecificData() : fKey(D) { }
T & operator*() { return *get(); }
T * operator->() { return get(); }
const GUSISpecific * Key() const { return &fKey; }
T * get(GUSISpecificTable * table);
T * get() { return get(GUSIContext::Current()); }
protected:
GUSISpecific fKey;
};
template <class T, GUSISpecificDestructor D>
T * GUSISpecificData<T,D>::get(GUSISpecificTable * table)
{
void * data = table->GetSpecific(&fKey);
if (!data)
table->SetSpecific(&fKey, data = new T);
return static_cast<T *>(data);
}
#if PRAGMA_STRUCT_ALIGN
#pragma options align=reset
#endif
// <Inline member functions for class [[GUSISpecific]]>=
inline GUSISpecific::GUSISpecific(GUSISpecificDestructor destructor)
: fDestructor(destructor), fID(sNextID++)
{
GUSISpecificTable::Register(this);
}
inline GUSISpecific::~GUSISpecific()
{
GUSISpecificTable::Destruct(this);
}
inline void GUSISpecific::Destruct(void * data)
{
if (fDestructor)
fDestructor(data);
}
// <Inline member functions for class [[GUSISpecificTable]]>=
inline bool GUSISpecificTable::Valid(const GUSISpecific * key) const
{
return key && key->fID < fAlloc;
}
// <Inline member functions for class [[GUSISpecificTable]]>=
inline GUSISpecificTable::GUSISpecificTable()
: fValues(nil), fAlloc(0)
{
}
// <Inline member functions for class [[GUSISpecificTable]]>=
inline void * GUSISpecificTable::GetSpecific(const GUSISpecific * key) const
{
if (Valid(key))
return fValues[0][key->fID];
else
return nil;
}
#endif /* GUSI_SOURCE */
#endif /* _GUSISpecific_ */