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/* -------------------------------------------------------------------------- */
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/* Copyright 2002-2012, OpenNebula Project Leads (OpenNebula.org) */
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/* */
/* Licensed under the Apache License, Version 2.0 (the "License"); you may */
/* not use this file except in compliance with the License. You may obtain */
/* a copy of the License at */
/* */
/* http://www.apache.org/licenses/LICENSE-2.0 */
/* */
/* Unless required by applicable law or agreed to in writing, software */
/* distributed under the License is distributed on an "AS IS" BASIS, */
/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. */
/* See the License for the specific language governing permissions and */
/* limitations under the License. */
/* -------------------------------------------------------------------------- */
# ifndef CALLBACKABLE_H_
# define CALLBACKABLE_H_
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# include <pthread.h>
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using namespace std ;
/**
* ObjectSQL class . Provides a SQL backend interface , it should be implemented
* by persistent objects .
*/
class Callbackable
{
public :
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Callbackable ( ) : cb ( 0 ) , arg ( 0 )
{
pthread_mutex_init ( & mutex , 0 ) ;
} ;
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virtual ~ Callbackable ( )
{
pthread_mutex_destroy ( & mutex ) ;
} ;
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/**
* Datatype for call back pointers
*/
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typedef int ( Callbackable : : * Callback ) ( void * , int , char * * , char * * ) ;
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/**
* Set the callback function and custom arguments to be executed by the
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* next SQL command , and locks the mutex until unset_callback is called .
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* @ param ptr to the callback function
* @ param arg custom arguments for the callback function
*/
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void set_callback ( Callback _cb , void * _arg = 0 )
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{
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pthread_mutex_lock ( & mutex ) ;
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cb = _cb ;
arg = _arg ;
} ;
/**
* Test if the CallBack is set for the object .
* @ return true if the callback is set
*/
bool isCallBackSet ( )
{
return ( cb ! = 0 ) ;
} ;
/**
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* Call the callback funcion set . This method must be called only if
* isCallBackSet returns true .
* @ return the callback function return value .
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*/
int do_callback ( int num , char * * values , char * * names )
{
return ( this - > * cb ) ( arg , num , values , names ) ;
} ;
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/**
* Unset the callback function .
*/
void unset_callback ( )
{
cb = 0 ;
arg = 0 ;
pthread_mutex_unlock ( & mutex ) ;
}
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private :
/**
* SQL callback to be executed for each row result of an SQL statement
*/
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Callback cb ;
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/**
* Custom arguments for the callback
*/
void * arg ;
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/**
* Mutex for locking the callback function .
*/
pthread_mutex_t mutex ;
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} ;
# endif /*CALLBACKABLE_H_*/