ACE_TSS< TYPE > Class Template Reference

Allows objects that are "physically" in thread specific storage (i.e., private to a thread) to be accessed as though they were "logically" global to a program. More...

#include <TSS_T.h>

Collaboration diagram for ACE_TSS< TYPE >:

Collaboration graph
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List of all members.

Public Member Functions

 ACE_TSS (TYPE *ts_obj=0)
virtual ~ACE_TSS (void)
TYPE * ts_object (TYPE *new_ts_obj)
virtual TYPE * make_TSS_TYPE (void) const
 Hook for construction parameters.
void dump (void) const
 Dump the state of an object.
Accessors
All accessors return a pointer to the calling thread's copy of the TYPE data. The pointer may be 0 on error conditions or if the calling thread's copy of the data has not yet been set. See specific method descriptions for complete details.

TYPE * ts_object (void) const
TYPE * operator-> () const
 operator TYPE * (void) const

Protected Member Functions

TYPE * ts_get (void) const
int ts_init (void)
void operator= (const ACE_TSS< TYPE > &)
 ACE_TSS (const ACE_TSS< TYPE > &)

Protected Attributes

TYPE * type_
 This implementation only works for non-threading systems...

Detailed Description

template<class TYPE>
class ACE_TSS< TYPE >

Allows objects that are "physically" in thread specific storage (i.e., private to a thread) to be accessed as though they were "logically" global to a program.

This class helps to maintain a separate copy of an object for each thread that needs access to it. All threads access a single instance of ACE_TSS to obtain a pointer to a thread-specific copy of a TYPE object. Using a pointer to TYPE in TSS instead of TYPE itself is useful because, in addition to avoiding copies on what may be a complex class, it allows assignment of objects to thread-specific data that have arbitrarily complex constructors.

When the ACE_TSS object is destroyed, all threads's instances of the data are deleted.

Modern compilers have no problem using a built-in type for TYPE. However, if you must use an older compiler that won't work with a built-in type, the ACE_TSS_Type_Adapter class template, below, can be used for adapting built-in types to work with ACE_TSS.

Note:
Beware when creating static instances of this type (as with any other, btw). The unpredictable order of initialization across different platforms may cause a situation where one uses the instance before it is fully initialized. That's why typically instances of this type are dynamicaly allocated. On the stack it is typically allocated inside the ACE_Thread::svc() method which limits its lifetime appropriately.

Definition at line 75 of file TSS_T.h.

Constructor & Destructor Documentation

template<class TYPE>
ACE_BEGIN_VERSIONED_NAMESPACE_DECL ACE_INLINE ACE_TSS< TYPE >::ACE_TSS ( TYPE *  ts_obj = 0  ) 

Default constructor. Can also initialize this ACE_TSS instance, readying it for use by the calling thread as well as all other threads in the process. If the constructor does not initialize this object, the first access to it will perform the initialization, which could possibly (under odd error conditions) fail.

Parameters:
ts_obj If non-zero, this object is initialized for use by all threads and ts_obj is used to set the thread-specific value for the calling thread. Other threads use the ts_object (TYPE *) method to set a specific value.

Definition at line 10 of file TSS_T.inl.

00011   : type_ (type)
00012 {
00013 }

template<class TYPE>
ACE_BEGIN_VERSIONED_NAMESPACE_DECL ACE_TSS< TYPE >::~ACE_TSS ( void   )  [virtual]

Deregister this object from thread-specific storage administration. Will cause all threads' copies of TYPE to be destroyed.

Definition at line 30 of file TSS_T.cpp.

References ACE_OS::thr_key_detach(), and ACE_OS::thr_keyfree().

00031 {
00032 #if defined (ACE_HAS_THREADS) && (defined (ACE_HAS_THREAD_SPECIFIC_STORAGE) || defined (ACE_HAS_TSS_EMULATION))
00033   if (this->once_)
00034   {
00035     ACE_OS::thr_key_detach (this->key_, this);
00036     ACE_OS::thr_keyfree (this->key_);
00037   }
00038 #else // defined (ACE_HAS_THREADS) && (defined (ACE_HAS_THREAD_SPECIFIC_STORAGE) || defined (ACE_HAS_TSS_EMULATION))
00039   // We own it, we need to delete it.
00040   delete type_;
00041 #endif // defined (ACE_HAS_THREADS) && (defined (ACE_HAS_THREAD_SPECIFIC_STORAGE) || defined (ACE_HAS_TSS_EMULATION))
00042 }

template<class TYPE>
ACE_TSS< TYPE >::ACE_TSS ( const ACE_TSS< TYPE > &   )  [protected]

Member Function Documentation

template<class TYPE>
void ACE_TSS< TYPE >::dump ( void   )  const

Dump the state of an object.

Definition at line 67 of file TSS_T.cpp.

References ACE_BEGIN_DUMP, ACE_DEBUG, ACE_END_DUMP, ACE_TEXT, and LM_DEBUG.

00068 {
00069 #if defined (ACE_HAS_DUMP)
00070 // ACE_TRACE ("ACE_TSS<TYPE>::dump");
00071 #if defined (ACE_HAS_THREADS) && (defined (ACE_HAS_THREAD_SPECIFIC_STORAGE) || defined (ACE_HAS_TSS_EMULATION))
00072   ACE_DEBUG ((LM_DEBUG, ACE_BEGIN_DUMP, this));
00073   this->keylock_.dump ();
00074   ACE_DEBUG ((LM_DEBUG, ACE_TEXT ("key_ = %d\n"), this->key_));
00075   ACE_DEBUG ((LM_DEBUG, ACE_TEXT ("\nonce_ = %d"), this->once_));
00076   ACE_DEBUG ((LM_DEBUG, ACE_TEXT ("\n")));
00077   ACE_DEBUG ((LM_DEBUG, ACE_END_DUMP));
00078 #endif /* defined (ACE_HAS_THREADS) && (defined (ACE_HAS_THREAD_SPECIFIC_STORAGE) || defined (ACE_HAS_TSS_EMULATION)) */
00079 #endif /* ACE_HAS_DUMP */
00080 }

template<class TYPE>
TYPE * ACE_TSS< TYPE >::make_TSS_TYPE ( void   )  const [virtual]

Hook for construction parameters.

Definition at line 57 of file TSS_T.cpp.

References ACE_NEW_RETURN.

00058 {
00059   TYPE *temp = 0;
00060   ACE_NEW_RETURN (temp,
00061                   TYPE,
00062                   0);
00063   return temp;
00064 }

template<class TYPE>
ACE_TSS< TYPE >::operator TYPE * ( void   )  const

Obtain a pointer to the calling thread's TYPE object. If this ACE_TSS object hasn't been initialized, this method will initialize it as a side-affect. If the calling thread has not set a value, a default-constructed instance of TYPE is allocated and it becomes the thread's instance.

Returns:
The calling thread's copy of the data. The returned pointer may be 0 under odd error conditions; check errno for further information.

Definition at line 51 of file TSS_T.cpp.

References ACE_TSS< TYPE >::ts_get().

00052 {
00053   return this->ts_get ();
00054 }

template<class TYPE>
TYPE * ACE_TSS< TYPE >::operator-> (  )  const

Use a "smart pointer" to get the thread-specific data associated with this object. If this ACE_TSS object hasn't been initialized, this method will initialize it as a side-affect. If the calling thread has not set a value, a default-constructed instance of TYPE is allocated and it becomes the thread's instance.

Returns:
The calling thread's copy of the data. The returned pointer may be 0 under odd error conditions; check errno for further information.

Definition at line 45 of file TSS_T.cpp.

References ACE_TSS< TYPE >::ts_get().

00046 {
00047   return this->ts_get ();
00048 }

template<class TYPE>
void ACE_TSS< TYPE >::operator= ( const ACE_TSS< TYPE > &   )  [protected]

template<class TYPE>
ACE_INLINE TYPE * ACE_TSS< TYPE >::ts_get ( void   )  const [protected]

Actually implements the code that retrieves the object from thread-specific storage.

Definition at line 35 of file TSS_T.inl.

References ACE_TSS< TYPE >::type_.

Referenced by ACE_TSS< TYPE >::operator TYPE *(), and ACE_TSS< TYPE >::operator->().

00036 {
00037   return this->type_;
00038 }

template<class TYPE>
ACE_INLINE int ACE_TSS< TYPE >::ts_init ( void   )  [protected]

Factors out common code for initializing TSS. This must NOT be called with the lock held...

Definition at line 16 of file TSS_T.inl.

00017 {
00018   return 0;
00019 }

template<class TYPE>
ACE_INLINE TYPE * ACE_TSS< TYPE >::ts_object ( void   )  const

Get the thread-specific object for this object.

Returns:
0 if the object has never been initialized, otherwise returns the calling thread's copy of the data. The returned pointer may be 0 under odd error conditions; check errno for further information.

Definition at line 22 of file TSS_T.inl.

References ACE_TSS< TYPE >::type_.

00023 {
00024   return this->type_;
00025 }

template<class TYPE>
ACE_INLINE TYPE * ACE_TSS< TYPE >::ts_object ( TYPE *  new_ts_obj  ) 

Set the thread-specific object for the calling thread. If this object has not been initialized yet, this method performs the initialization.

Parameters:
new_ts_obj The new value for the calling thread's copy of this object.
Returns:
The previous value of the calling thread's copy of this object; 0 if there was no previous value. This method also returns 0 on errors. To tell the difference between an error and a returned 0 pointer, it's recommended that one set errno to 0 prior to calling ts_object() and check for a new errno value if ts_object() returns 0.

Definition at line 28 of file TSS_T.inl.

References ACE_TSS< TYPE >::type_.

00029 {
00030   this->type_ = type;
00031   return this->type_;
00032 }

Member Data Documentation

template<class TYPE>
TYPE* ACE_TSS< TYPE >::type_ [protected]

This implementation only works for non-threading systems...

Definition at line 183 of file TSS_T.h.

Referenced by ACE_TSS< TYPE >::ts_get(), and ACE_TSS< TYPE >::ts_object().

The documentation for this class was generated from the following files:
Generated on Tue Feb 2 17:35:49 2010 for ACE by  doxygen 1.4.7