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/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
*
* Copyright (C) 2010 PrimeBase Technologies GmbH, Germany
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* Barry Leslie
*
* 2010-05-12
*/
#include "config.h"
#include <string>
#include <vector>
#include "drizzled/session.h"
#include "drizzled/table_list.h"
#include "drizzled/table_share.h"
#include "drizzled/module/registry.h"
#include "drizzled/plugin/event_observer.h"
#include <drizzled/util/functors.h>
#include <algorithm>
using namespace std;
namespace drizzled
{
namespace plugin
{
/*============================*/
// Basic plugin registration stuff.
static vector<EventObserver *> all_event_plugins;
//---------
bool EventObserver::addPlugin(EventObserver *handler)
{
if (handler != NULL)
all_event_plugins.push_back(handler);
return false;
}
//---------
void EventObserver::removePlugin(EventObserver *handler)
{
if (handler != NULL)
all_event_plugins.erase(find(all_event_plugins.begin(), all_event_plugins.end(), handler));
}
/*
* The Event Observer list class in which plugins register which events they
* are interested in.
*
* Each table share for example, will have one of these hung on it to store
* a list off all event observers interested in it and which events they are
* interested in.
*/
class EventObserverList
{
public:
typedef multimap<uint32_t, EventObserver *> ObserverMap;
private:
/* A list of lists indexed by event type. */
vector<ObserverMap *> event_observer_lists;
public:
EventObserverList()
{
uint32_t i;
event_observer_lists.reserve(EventObserver::MAX_EVENT_COUNT);
for (i=0; i < EventObserver::MAX_EVENT_COUNT; i++)
{
event_observer_lists[i]= NULL;
}
}
~EventObserverList()
{
clearAllObservers();
}
/* Add the observer to the observer list for the even, positioning it if required.
*
* Note: Event observers are storted in a multimap object so that the order in which
* they are called can be sorted based on the requested position. Lookups are never done
* on the multimap, once filled it is used as a vector.
*/
void addObserver(EventObserver *eventObserver, enum EventObserver::EventType event, int32_t position)
{
uint32_t event_pos;
ObserverMap *observers;
observers= event_observer_lists[event];
if (observers == NULL)
{
observers= new ObserverMap();
event_observer_lists[event]= observers;
}
if (position == 0)
event_pos= INT32_MAX; // Set the event position to be in the middle.
else
event_pos= (uint32_t) position;
/* If positioned then check if the position is already taken. */
if (position)
{
if (observers->find(event_pos) != observers->end())
{
errmsg_printf(ERRMSG_LVL_WARN,
_("EventObserverList::addEventObserver() Duplicate event position %d for event '%s' from EventObserver plugin '%s'"),
position,
EventObserver::eventName(event),
eventObserver->getName().c_str());
}
}
observers->insert(pair<uint32_t, EventObserver *>(event_pos, eventObserver) );
}
/* Remove all observer from all lists. */
void clearAllObservers()
{
for_each(event_observer_lists.begin(),
event_observer_lists.end(),
DeletePtr());
event_observer_lists.clear();
}
/* Get the observer list for an event type. Will return NULL if no observer exists.*/
ObserverMap *getObservers(enum EventObserver::EventType event)
{
return event_observer_lists[event];
}
};
//---------
/* registerEvent() is called from the event observer plugins to add themselves to
* the event observer list to be notified when the specified event takes place.
*/
void EventObserver::registerEvent(EventObserverList &observers, EventType event, int32_t position)
{
observers.addObserver(this, event, position);
}
/*========================================================*/
/* Table Event Observer handling: */
/*========================================================*/
//----------
/* For each EventObserver plugin call its registerTableEventsDo() meathod so that it can
* register what events, if any, it is interested in on this table.
*/
class RegisterTableEventsIterate : public unary_function<EventObserver *, void>
{
TableShare &table_share;
EventObserverList &observers;
public:
RegisterTableEventsIterate(TableShare &table_share_arg, EventObserverList &observers_arg):
table_share(table_share_arg), observers(observers_arg) {}
inline result_type operator() (argument_type eventObserver)
{
eventObserver->registerTableEventsDo(table_share, observers);
}
};
//----------
/*
* registerTableEvents() is called by drizzle to register all plugins that
* may be interested in table events on the newly created TableShare object.
*/
void EventObserver::registerTableEvents(TableShare &table_share)
{
if (all_event_plugins.empty())
return;
EventObserverList *observers;
observers= table_share.getTableObservers();
if (observers == NULL)
{
observers= new EventObserverList();
table_share.setTableObservers(observers);
}
else
{
/* Calling registerTableEvents() for a table that already has
* events registered on it is probably a programming error.
*/
observers->clearAllObservers();
}
for_each(all_event_plugins.begin(), all_event_plugins.end(),
RegisterTableEventsIterate(table_share, *observers));
}
//----------
/* Cleanup before freeing the TableShare object. */
void EventObserver::deregisterTableEvents(TableShare &table_share)
{
if (all_event_plugins.empty())
return;
EventObserverList *observers;
observers= table_share.getTableObservers();
if (observers)
{
table_share.setTableObservers(NULL);
observers->clearAllObservers();
delete observers;
}
}
/*========================================================*/
/* Schema Event Observer handling: */
/*========================================================*/
//----------
/* For each EventObserver plugin call its registerSchemaEventsDo() meathod so that it can
* register what events, if any, it is interested in on the schema.
*/
class RegisterSchemaEventsIterate : public unary_function<EventObserver *, void>
{
const std::string &db;
EventObserverList &observers;
public:
RegisterSchemaEventsIterate(const std::string &db_arg, EventObserverList &observers_arg) :
db(db_arg),
observers(observers_arg){}
inline result_type operator() (argument_type eventObserver)
{
eventObserver->registerSchemaEventsDo(db, observers);
}
};
//----------
/*
* registerSchemaEvents() is called by drizzle to register all plugins that
* may be interested in schema events on the database.
*/
void EventObserver::registerSchemaEvents(Session &session, const std::string &db)
{
if (all_event_plugins.empty())
return;
EventObserverList *observers;
observers= session.getSchemaObservers(db);
if (observers == NULL)
{
observers= new EventObserverList();
session.setSchemaObservers(db, observers);
}
for_each(all_event_plugins.begin(), all_event_plugins.end(),
RegisterSchemaEventsIterate(db, *observers));
}
//----------
/* Cleanup before freeing the Session object. */
void EventObserver::deregisterSchemaEvents(Session &session, const std::string &db)
{
if (all_event_plugins.empty())
return;
EventObserverList *observers;
observers= session.getSchemaObservers(db);
if (observers)
{
session.setSchemaObservers(db, NULL);
observers->clearAllObservers();
delete observers;
}
}
/*========================================================*/
/* Session Event Observer handling: */
/*========================================================*/
//----------
/* For each EventObserver plugin call its registerSessionEventsDo() meathod so that it can
* register what events, if any, it is interested in on this session.
*/
class RegisterSessionEventsIterate : public unary_function<EventObserver *, void>
{
Session &session;
EventObserverList &observers;
public:
RegisterSessionEventsIterate(Session &session_arg, EventObserverList &observers_arg) :
session(session_arg), observers(observers_arg) {}
inline result_type operator() (argument_type eventObserver)
{
eventObserver->registerSessionEventsDo(session, observers);
}
};
//----------
/*
* registerSessionEvents() is called by drizzle to register all plugins that
* may be interested in session events on the newly created session.
*/
void EventObserver::registerSessionEvents(Session &session)
{
if (all_event_plugins.empty())
return;
EventObserverList *observers;
observers= session.getSessionObservers();
if (observers == NULL)
{
observers= new EventObserverList();
session.setSessionObservers(observers);
}
observers->clearAllObservers();
for_each(all_event_plugins.begin(), all_event_plugins.end(),
RegisterSessionEventsIterate(session, *observers));
}
//----------
/* Cleanup before freeing the session object. */
void EventObserver::deregisterSessionEvents(Session &session)
{
if (all_event_plugins.empty())
return;
EventObserverList *observers;
observers= session.getSessionObservers();
if (observers)
{
session.setSessionObservers(NULL);
observers->clearAllObservers();
delete observers;
}
}
/* Event observer list iterator: */
//----------
class EventIterate : public unary_function<pair<uint32_t, EventObserver *>, bool>
{
EventData &data;
public:
EventIterate(EventData &data_arg) :
unary_function<pair<uint32_t, EventObserver *>, bool>(),
data(data_arg)
{}
inline result_type operator()(argument_type handler)
{
bool result= handler.second->observeEventDo(data);
if (result)
{
/* TRANSLATORS: The leading word "EventObserver" is the name
of the plugin api, and so should not be translated. */
errmsg_printf(ERRMSG_LVL_ERROR,
_("EventIterate event handler '%s' failed for event '%s'"),
handler.second->getName().c_str(), handler.second->eventName(data.event));
}
return result;
}
};
/*==========================================================*/
/* Generic meathods called by drizzle to notify all interested
* plugins of an event,
*/
// Call all event observers interested in the event.
bool EventData::callEventObservers()
{
EventObserverList::ObserverMap *eventObservers;
eventObservers = observerList->getObservers(event);
if (eventObservers == NULL)
return false; // Nobody was interested in the event. :(
/* Use find_if instead of foreach so that we can collect return codes */
EventObserverList::ObserverMap::iterator iter=
find_if(eventObservers->begin(), eventObservers->end(),
EventIterate(*this));
/* If iter is == end() here, that means that all of the plugins returned
* false, which in this case means they all succeeded. Since we want to
* return false on success, we return the value of the two being !=.
*/
return iter != eventObservers->end();
}
//--------
bool SessionEventData::callEventObservers()
{
observerList= session.getSessionObservers();
return EventData::callEventObservers();
}
//--------
bool SchemaEventData::callEventObservers()
{
observerList= session.getSchemaObservers(db);
if (!observerList)
{
EventObserver::registerSchemaEvents(session, db);
observerList= session.getSchemaObservers(db);
}
return EventData::callEventObservers();
}
//--------
bool TableEventData::callEventObservers()
{
observerList= table.s->getTableObservers();
return EventData::callEventObservers();
}
/*==========================================================*/
/* Static meathods called by drizzle to notify interested plugins
* of a schema event,
*/
bool EventObserver::beforeDropTable(Session &session, TableIdentifier &table)
{
if (all_event_plugins.empty())
return false;
BeforeDropTableEventData eventData(session, table);
return eventData.callEventObservers();
}
bool EventObserver::afterDropTable(Session &session, TableIdentifier &table, int err)
{
if (all_event_plugins.empty())
return false;
AfterDropTableEventData eventData(session, table, err);
return eventData.callEventObservers();
}
bool EventObserver::beforeRenameTable(Session &session, TableIdentifier &from, TableIdentifier &to)
{
if (all_event_plugins.empty())
return false;
BeforeRenameTableEventData eventData(session, from, to);
return eventData.callEventObservers();
}
bool EventObserver::afterRenameTable(Session &session, TableIdentifier &from, TableIdentifier &to, int err)
{
if (all_event_plugins.empty())
return false;
AfterRenameTableEventData eventData(session, from, to, err);
return eventData.callEventObservers();
}
/*==========================================================*/
/* Static meathods called by drizzle to notify interested plugins
* of a table event,
*/
bool EventObserver::beforeInsertRecord(Table &table, unsigned char *buf)
{
if (all_event_plugins.empty())
return false;
BeforeInsertRecordEventData eventData(*(table.in_use), table, buf);
return eventData.callEventObservers();
}
bool EventObserver::afterInsertRecord(Table &table, const unsigned char *buf, int err)
{
if (all_event_plugins.empty())
return false;
AfterInsertRecordEventData eventData(*(table.in_use), table, buf, err);
return eventData.callEventObservers();
}
bool EventObserver::beforeDeleteRecord(Table &table, const unsigned char *buf)
{
if (all_event_plugins.empty())
return false;
BeforeDeleteRecordEventData eventData(*(table.in_use), table, buf);
return eventData.callEventObservers();
}
bool EventObserver::afterDeleteRecord(Table &table, const unsigned char *buf, int err)
{
if (all_event_plugins.empty())
return false;
AfterDeleteRecordEventData eventData(*(table.in_use), table, buf, err);
return eventData.callEventObservers();
}
bool EventObserver::beforeUpdateRecord(Table &table, const unsigned char *old_data, unsigned char *new_data)
{
if (all_event_plugins.empty())
return false;
BeforeUpdateRecordEventData eventData(*(table.in_use), table, old_data, new_data);
return eventData.callEventObservers();
}
bool EventObserver::afterUpdateRecord(Table &table, const unsigned char *old_data, unsigned char *new_data, int err)
{
if (all_event_plugins.empty())
return false;
AfterUpdateRecordEventData eventData(*(table.in_use), table, old_data, new_data, err);
return eventData.callEventObservers();
}
/*==========================================================*/
/* Static meathods called by drizzle to notify interested plugins
* of a session event,
*/
bool EventObserver::beforeCreateDatabase(Session &session, const std::string &db)
{
if (all_event_plugins.empty())
return false;
BeforeCreateDatabaseEventData eventData(session, db);
return eventData.callEventObservers();
}
bool EventObserver::afterCreateDatabase(Session &session, const std::string &db, int err)
{
if (all_event_plugins.empty())
return false;
AfterCreateDatabaseEventData eventData(session, db, err);
return eventData.callEventObservers();
}
bool EventObserver::beforeDropDatabase(Session &session, const std::string &db)
{
if (all_event_plugins.empty())
return false;
BeforeDropDatabaseEventData eventData(session, db);
return eventData.callEventObservers();
}
bool EventObserver::afterDropDatabase(Session &session, const std::string &db, int err)
{
if (all_event_plugins.empty())
return false;
AfterDropDatabaseEventData eventData(session, db, err);
return eventData.callEventObservers();
}
} /* namespace plugin */
} /* namespace drizzled */
|