~drizzle-trunk/drizzle/development

/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-

 *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:

 *

 *  Definitions required for EventObserver plugin

 *

 *  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

 */

/*

 * How to add a new event:

 *

 * In event_observer.h

 * 1: Add your event to EventType.

 * 2: Add it to EventObserver::eventName().

 * 3: Cerate a EventData class for it based on SessionEventData, SchemaEventData, 

 *  or TableEventData depending on the event type class.

 * 4: Add a static method to the EventObserver class, similar to beforeInsertRecord() for example,

 *  that will be called by drizzle.

 *

 * In event_observer.cc

 * 5: Impliment your static event method, similar to beforeInsertRecord() for example.

 * 6: Depending on the event type class add an event vector for it to the SessionEventObservers,

 *  SchemaEventObservers, or TableEventObservers class.

 *

 */

#pragma once

#include <drizzled/plugin/plugin.h>

#include <string>

#include <drizzled/visibility.h>

namespace drizzled {

namespace plugin {

typedef std::vector<EventObserver *> EventObserverVector;

typedef EventObserver* EventObserverPtr;

class DRIZZLED_API EventObserver : public Plugin

{

public:

  explicit EventObserver(std::string name_arg)

    : Plugin(name_arg, "EventObserver")

  {}

  enum EventType{

    /* Session events: */

    BEFORE_CREATE_DATABASE, AFTER_CREATE_DATABASE, 

    BEFORE_DROP_DATABASE,   AFTER_DROP_DATABASE,

    CONNECT_SESSION,

    DISCONNECT_SESSION,

    AFTER_STATEMENT,

    BEFORE_STATEMENT,

    /* Schema events: */

    BEFORE_DROP_TABLE,   AFTER_DROP_TABLE, 

    BEFORE_RENAME_TABLE, AFTER_RENAME_TABLE, 

    /* Table events: */

    BEFORE_INSERT_RECORD,   AFTER_INSERT_RECORD, 

    BEFORE_UPDATE_RECORD,   AFTER_UPDATE_RECORD, 

    BEFORE_DELETE_RECORD,   AFTER_DELETE_RECORD,

    /* The max event ID marker. */

    MAX_EVENT_COUNT

  };

  static const char *eventName(EventType event) 

  {

    switch(event) 

    {

    case BEFORE_DROP_TABLE:

      return "BEFORE_DROP_TABLE";

    case AFTER_DROP_TABLE:

      return "AFTER_DROP_TABLE";

    case BEFORE_RENAME_TABLE:

      return "BEFORE_RENAME_TABLE";

    case AFTER_RENAME_TABLE:

      return "AFTER_RENAME_TABLE";

    case BEFORE_INSERT_RECORD:

      return "BEFORE_INSERT_RECORD";

    case AFTER_INSERT_RECORD:

      return "AFTER_INSERT_RECORD";

    case BEFORE_UPDATE_RECORD:

      return "BEFORE_UPDATE_RECORD";

    case AFTER_UPDATE_RECORD:

      return "AFTER_UPDATE_RECORD";

    case BEFORE_DELETE_RECORD:

      return "BEFORE_DELETE_RECORD";

    case AFTER_DELETE_RECORD:

      return "AFTER_DELETE_RECORD";

    case BEFORE_CREATE_DATABASE:

      return "BEFORE_CREATE_DATABASE";

    case AFTER_CREATE_DATABASE:

      return "AFTER_CREATE_DATABASE";

    case BEFORE_DROP_DATABASE:

      return "BEFORE_DROP_DATABASE";

    case AFTER_DROP_DATABASE:

      return "AFTER_DROP_DATABASE";

    case CONNECT_SESSION:

      return "CONNECT_SESSION";

    case DISCONNECT_SESSION:

      return "DISCONNECT_SESSION";

    case AFTER_STATEMENT:

      return "AFTER_STATEMENT";

    case BEFORE_STATEMENT:

      return "BEFORE_STATEMENT";

    case MAX_EVENT_COUNT:

      break;

    }

    return "Unknown";

  }

  /*==========================================================*/

  /* registerEvents() must be implemented to allow the plugin to

   * register which events it is interested in.

 */

  virtual void registerTableEventsDo(TableShare &, EventObserverList &){}

  virtual void registerSchemaEventsDo(const std::string &/*db*/, EventObserverList &) {}

  virtual void registerSessionEventsDo(Session &, EventObserverList &) {}

  virtual bool observeEventDo(EventData &)= 0;

  /*==========================================================*/

  /* Static access methods called by drizzle: */

  static bool addPlugin(EventObserver *handler);

  static void removePlugin(EventObserver *handler);

  /*==========================================================*/

  /* Register an event of interest for this plugin. 

   * This is called from with in the plugin when registering itself.

   *

   * The position field is used to indicate the order the event observer is to be 

   * called. If the event observer must be called before any other observer then 

   * the position must be set to 1. If it must be called last then the position must be 

   * set to -1. A position of 0 indicated the position doesn't matter.

   *

   * If 2 plugins require the same position then which is called first in not guarenteed.

   * In this case a warrning will be logged but execution will continue.

   * 

   * It is good practice that if the event position matters not to hard code the position

   * but supply a systen variable so that it can be set at runtime so that the user can

   * decide which event should be called first.

 */

  void registerEvent(EventObserverList &observers, EventType event, int32_t position= 0); 

  /*==========================================================*/

  /* Called from drizzle to register all events for all event plugins 

   * interested in this table. 

 */

  static void registerTableEvents(TableShare &table_share); 

  static void deregisterTableEvents(TableShare &table_share); 

  /*==========================================================*/

  /* Called from drizzle to register all events for all event plugins 

   * interested in this database. 

 */

  static void registerSchemaEvents(Session &session, const std::string &db); 

  static void deregisterSchemaEvents(EventObserverList *observers); 

  /*==========================================================*/

  /* Called from drizzle to register all events for all event plugins 

   * interested in this session. 

 */

  static void registerSessionEvents(Session &session); 

  static void deregisterSessionEvents(EventObserverList *observers); 

  /*==========================================================*/

  /* Static meathods called by drizzle to notify interested plugins 

   * of a schema an event,

 */

  static bool beforeDropTable(Session &session, const drizzled::identifier::Table &table);

  static bool afterDropTable(Session &session, const drizzled::identifier::Table &table, int err);

  static bool beforeRenameTable(Session &session, const drizzled::identifier::Table &from, const drizzled::identifier::Table &to);

  static bool afterRenameTable(Session &session, const drizzled::identifier::Table &from, const drizzled::identifier::Table &to, int err);

  static bool connectSession(Session &session);

  static bool disconnectSession(Session &session);

  static bool beforeStatement(Session &session);

  static bool afterStatement(Session &session);

  /*==========================================================*/

  /* Static meathods called by drizzle to notify interested plugins 

   * of a table an event,

 */

  static bool beforeInsertRecord(Table &table, unsigned char *buf);

  static bool afterInsertRecord(Table &table, const unsigned char *buf, int err);

  static bool beforeDeleteRecord(Table &table, const unsigned char *buf);

  static bool afterDeleteRecord(Table &table, const unsigned char *buf, int err);

  static bool beforeUpdateRecord(Table &table, const unsigned char *old_data, unsigned char *new_data);

  static bool afterUpdateRecord(Table &table, const unsigned char *old_data, unsigned char *new_data, int err);

  /*==========================================================*/

  /* Static meathods called by drizzle to notify interested plugins 

   * of a table an event,

 */

  static bool beforeCreateDatabase(Session &session, const std::string &db);

  static bool afterCreateDatabase(Session &session, const std::string &db, int err);

  static bool beforeDropDatabase(Session &session, const std::string &db);

  static bool afterDropDatabase(Session &session, const std::string &db, int err);

  static const EventObserverVector &getEventObservers(void);

};

/* EventObserver data classes: */

//======================================

class EventData

{

public:

  EventObserver::EventType event;

  EventData(EventObserver::EventType event_arg): 

    event(event_arg),

    observerList(NULL)

  {}

  virtual ~EventData(){}

  // Call all the event observers that are registered for this event.

  virtual bool callEventObservers();

protected:

  EventObserverList *observerList;

};

//-----

class SessionEventData: public EventData

{

public:

  Session &session;

  SessionEventData(EventObserver::EventType event_arg, Session &session_arg): 

    EventData(event_arg),

    session(session_arg)

  {}

  // Call all the event observers that are registered for this event.

  virtual bool callEventObservers();

  static bool hasEvents(Session &in_session);

};

//-----

class SchemaEventData: public EventData

{

public:

  Session &session;

  const std::string &db;

  SchemaEventData(EventObserver::EventType event_arg, Session &session_arg, const std::string &db_arg): 

    EventData(event_arg),

    session(session_arg),

    db(db_arg)

  {}

  // Call all the event observers that are registered for this event.

  virtual bool callEventObservers();

};

//-----

class TableEventData: public EventData

{

public:

  Session &session;

  Table &table;  

  TableEventData(EventObserver::EventType event_arg, Session &session_arg, Table &table_arg): 

    EventData(event_arg),

    session(session_arg),

    table(table_arg)

  {}

  // Call all the event observers that are registered for this event.

  virtual bool callEventObservers();

  static bool hasEvents(Table &in_table);

};

//-----

class BeforeCreateDatabaseEventData: public SessionEventData

{

public:

  const std::string &db;

  BeforeCreateDatabaseEventData(Session &session_arg, const std::string &db_arg): 

    SessionEventData(EventObserver::BEFORE_CREATE_DATABASE, session_arg), 

    db(db_arg)

  {}  

};

//-----

class AfterCreateDatabaseEventData: public SessionEventData

{

public:

  const std::string &db;

  int err;

  AfterCreateDatabaseEventData(Session &session_arg, const std::string &db_arg, int err_arg): 

    SessionEventData(EventObserver::AFTER_CREATE_DATABASE, session_arg), 

    db(db_arg), 

    err(err_arg)

  {}  

};

//-----

class BeforeDropDatabaseEventData: public SessionEventData

{

public:

  const std::string &db;

  BeforeDropDatabaseEventData(Session &session_arg, const std::string &db_arg): 

    SessionEventData(EventObserver::BEFORE_DROP_DATABASE, session_arg), 

    db(db_arg)

  {}  

};

//-----

class AfterDropDatabaseEventData: public SessionEventData

{

public:

  const std::string &db;

  int err;

  AfterDropDatabaseEventData(Session &session_arg, const std::string &db_arg, int err_arg): 

    SessionEventData(EventObserver::AFTER_DROP_DATABASE, session_arg), 

    db(db_arg), 

    err(err_arg) 

  {}  

};

//-----

class ConnectSessionEventData: public SessionEventData

{

public:

  ConnectSessionEventData(Session &session_arg):

    SessionEventData(EventObserver::CONNECT_SESSION, session_arg)

  {}  

};

//-----

class DisconnectSessionEventData: public SessionEventData

{

public:

  DisconnectSessionEventData(Session &session_arg):

    SessionEventData(EventObserver::DISCONNECT_SESSION, session_arg)

  {}  

};

//-----

class BeforeStatementEventData: public SessionEventData

{

public:

  BeforeStatementEventData(Session &session_arg):

    SessionEventData(EventObserver::BEFORE_STATEMENT, session_arg)

  {}  

};

//-----

class AfterStatementEventData: public SessionEventData

{

public:

  AfterStatementEventData(Session &session_arg):

    SessionEventData(EventObserver::AFTER_STATEMENT, session_arg)

  {}  

};

//-----

class BeforeDropTableEventData: public SchemaEventData

{

public:

  const drizzled::identifier::Table &table;

  BeforeDropTableEventData(Session &session_arg, const drizzled::identifier::Table &table_arg): 

    SchemaEventData(EventObserver::BEFORE_DROP_TABLE, session_arg, table_arg.getSchemaName()), 

    table(table_arg)

  {}  

};

//-----

class AfterDropTableEventData: public SchemaEventData

{

public:

  const drizzled::identifier::Table &table;

  int err;

  AfterDropTableEventData(Session &session_arg, const drizzled::identifier::Table &table_arg, int err_arg): 

    SchemaEventData(EventObserver::AFTER_DROP_TABLE, session_arg, table_arg.getSchemaName()), 

    table(table_arg), 

    err(err_arg)

  {}  

};

//-----

class BeforeRenameTableEventData: public SchemaEventData

{

public:

  const drizzled::identifier::Table &from;

  const drizzled::identifier::Table &to;

  BeforeRenameTableEventData(Session &session_arg, const drizzled::identifier::Table &from_arg, const drizzled::identifier::Table &to_arg): 

    SchemaEventData(EventObserver::BEFORE_RENAME_TABLE, session_arg, from_arg.getSchemaName()), 

    from(from_arg), 

    to(to_arg)

  {}  

};

//-----

class AfterRenameTableEventData: public SchemaEventData

{

public:

  const drizzled::identifier::Table &from;

  const drizzled::identifier::Table &to;

  int err;

  AfterRenameTableEventData(Session &session_arg, const drizzled::identifier::Table &from_arg, const drizzled::identifier::Table &to_arg, int err_arg): 

    SchemaEventData(EventObserver::AFTER_RENAME_TABLE, session_arg, from_arg.getSchemaName()), 

    from(from_arg), 

    to(to_arg), 

    err(err_arg)

  {}  

};

//-----

class BeforeInsertRecordEventData: public TableEventData

{

public:

  unsigned char *row;

  BeforeInsertRecordEventData(Session &session_arg, Table &table_arg, unsigned char *row_arg): 

    TableEventData(EventObserver::BEFORE_INSERT_RECORD, session_arg, table_arg), 

    row(row_arg)

  {}  

};

//-----

class AfterInsertRecordEventData: public TableEventData

{

public:

  const unsigned char *row;

  int err;

  AfterInsertRecordEventData(Session &session_arg, Table &table_arg, const unsigned char *row_arg, int err_arg): 

    TableEventData(EventObserver::AFTER_INSERT_RECORD, session_arg, table_arg), 

    row(row_arg),

    err(err_arg)

  {}  

};

//-----

class BeforeDeleteRecordEventData: public TableEventData

{

public:

  const unsigned char *row;

  BeforeDeleteRecordEventData(Session &session_arg, Table &table_arg, const unsigned char *row_arg): 

    TableEventData(EventObserver::BEFORE_DELETE_RECORD, session_arg, table_arg), 

    row(row_arg)

  {}  

};

//-----

class AfterDeleteRecordEventData: public TableEventData

{

public:

  const unsigned char *row;

  int err;

  AfterDeleteRecordEventData(Session &session_arg, Table &table_arg, const unsigned char *row_arg, int err_arg): 

    TableEventData(EventObserver::AFTER_DELETE_RECORD, session_arg, table_arg), 

    row(row_arg),

    err(err_arg)

  {}  

};

//-----

class BeforeUpdateRecordEventData: public TableEventData

{

public:

  const unsigned char *old_row;

  unsigned char *new_row;

  BeforeUpdateRecordEventData(Session &session_arg, Table &table_arg,  

                              const unsigned char *old_row_arg, 

                              unsigned char *new_row_arg): 

    TableEventData(EventObserver::BEFORE_UPDATE_RECORD, session_arg, table_arg), 

    old_row(old_row_arg),

    new_row(new_row_arg)      

  {}  

};

//-----

class AfterUpdateRecordEventData: public TableEventData

{

public:

  const unsigned char *old_row;

  const unsigned char *new_row;

  int err;

  AfterUpdateRecordEventData(Session &session_arg, Table &table_arg, 

                             const unsigned char *old_row_arg, 

                             const unsigned char *new_row_arg, 

                             int err_arg): 

    TableEventData(EventObserver::AFTER_UPDATE_RECORD, session_arg, table_arg), 

    old_row(old_row_arg),

    new_row(new_row_arg),

    err(err_arg)

  {}  

};

//=======================================================

} /* namespace plugin */

} /* namespace drizzled */