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/* -------------------------------------------------------------------------- */
/* Copyright 2002-2012, OpenNebula Project Leads (OpenNebula.org) */
/* */
/* 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_
#include <pthread.h>
using namespace std;
/**
* ObjectSQL class. Provides a SQL backend interface, it should be implemented
* by persistent objects.
*/
class Callbackable
{
public:
Callbackable():cb(0),arg(0)
{
pthread_mutex_init(&mutex,0);
};
virtual ~Callbackable()
{
pthread_mutex_destroy(&mutex);
};
/**
* Datatype for call back pointers
*/
typedef int (Callbackable::*Callback)(void *, int, char ** ,char **);
/**
* Set the callback function and custom arguments to be executed by the
* next SQL command, and locks the mutex until unset_callback is called.
* @param ptr to the callback function
* @param arg custom arguments for the callback function
*/
void set_callback(Callback _cb, void * _arg = 0)
{
pthread_mutex_lock(&mutex);
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);
};
/**
* Call the callback funcion set. This method must be called only if
* isCallBackSet returns true.
* @return the callback function return value.
*/
int do_callback(int num, char **values, char **names)
{
return (this->*cb)(arg, num, values, names);
};
/**
* Unset the callback function.
*/
void unset_callback()
{
cb = 0;
arg = 0;
pthread_mutex_unlock(&mutex);
}
private:
/**
* SQL callback to be executed for each row result of an SQL statement
*/
Callback cb;
/**
* Custom arguments for the callback
*/
void * arg;
/**
* Mutex for locking the callback function.
*/
pthread_mutex_t mutex;
};
#endif /*CALLBACKABLE_H_*/
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