llevent.h
上传用户:king477883
上传日期:2021-03-01
资源大小:9553k
文件大小:6k
- /**
- * @file llevent.h
- * @author Tom Yedwab
- * @brief LLEvent and LLEventListener base classes.
- *
- * $LicenseInfo:firstyear=2001&license=viewergpl$
- *
- * Copyright (c) 2001-2010, Linden Research, Inc.
- *
- * Second Life Viewer Source Code
- * The source code in this file ("Source Code") is provided by Linden Lab
- * to you under the terms of the GNU General Public License, version 2.0
- * ("GPL"), unless you have obtained a separate licensing agreement
- * ("Other License"), formally executed by you and Linden Lab. Terms of
- * the GPL can be found in doc/GPL-license.txt in this distribution, or
- * online at http://secondlifegrid.net/programs/open_source/licensing/gplv2
- *
- * There are special exceptions to the terms and conditions of the GPL as
- * it is applied to this Source Code. View the full text of the exception
- * in the file doc/FLOSS-exception.txt in this software distribution, or
- * online at
- * http://secondlifegrid.net/programs/open_source/licensing/flossexception
- *
- * By copying, modifying or distributing this software, you acknowledge
- * that you have read and understood your obligations described above,
- * and agree to abide by those obligations.
- *
- * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
- * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
- * COMPLETENESS OR PERFORMANCE.
- * $/LicenseInfo$
- */
- #ifndef LL_EVENT_H
- #define LL_EVENT_H
- #include "llsd.h"
- #include "llpointer.h"
- #include "llthread.h"
- namespace LLOldEvents
- {
- class LLEventListener;
- class LLEvent;
- class LLEventDispatcher;
- class LLObservable;
- // Abstract event. All events derive from LLEvent
- class LL_COMMON_API LLEvent : public LLThreadSafeRefCount
- {
- protected:
- virtual ~LLEvent();
-
- public:
- LLEvent(LLObservable* source, const std::string& desc = "") : mSource(source), mDesc(desc) { }
- LLObservable* getSource() { return mSource; }
- virtual LLSD getValue() { return LLSD(); }
- // Determines whether this particular listener
- // should be notified of this event.
- // If this function returns true, handleEvent is
- // called on the listener with this event as the
- // argument.
- // Defaults to handling all events. Override this
- // if associated with an Observable with many different listeners
- virtual bool accept(LLEventListener* listener);
- // return a string describing the event
- virtual const std::string& desc();
- private:
- LLObservable* mSource;
- std::string mDesc;
- };
- // Abstract listener. All listeners derive from LLEventListener
- class LL_COMMON_API LLEventListener : public LLThreadSafeRefCount
- {
- protected:
- virtual ~LLEventListener();
-
- public:
- // Processes the event.
- // TODO: Make the return value less ambiguous?
- virtual bool handleEvent(LLPointer<LLEvent> event, const LLSD& userdata) = 0;
- // Called when an dispatcher starts/stops listening
- virtual bool handleAttach(LLEventDispatcher *dispatcher) = 0;
- virtual bool handleDetach(LLEventDispatcher *dispatcher) = 0;
- };
- // A listener which tracks references to it and cleans up when it's deallocated
- class LL_COMMON_API LLSimpleListener : public LLEventListener
- {
- public:
- void clearDispatchers();
- virtual bool handleAttach(LLEventDispatcher *dispatcher);
- virtual bool handleDetach(LLEventDispatcher *dispatcher);
- protected:
- ~LLSimpleListener();
- std::vector<LLEventDispatcher *> mDispatchers;
- };
- class LLObservable; // defined below
- // A structure which stores a Listener and its metadata
- struct LLListenerEntry
- {
- LLEventListener* listener;
- LLSD filter;
- LLSD userdata;
- };
- // Base class for a dispatcher - an object which listens
- // to events being fired and relays them to their
- // appropriate destinations.
- class LL_COMMON_API LLEventDispatcher : public LLThreadSafeRefCount
- {
- protected:
- virtual ~LLEventDispatcher();
-
- public:
- // The default constructor creates a default simple dispatcher implementation.
- // The simple implementation has an array of listeners and fires every event to
- // all of them.
- LLEventDispatcher();
-
- // This dispatcher is being attached to an observable object.
- // If we return false, the attach fails.
- bool engage(LLObservable* observable);
- // This dispatcher is being detached from an observable object.
- void disengage(LLObservable* observable);
- // Adds a listener to this dispatcher, with a given user data
- // that will be passed to the listener when an event is fired.
- // Duplicate pointers are removed on addtion.
- void addListener(LLEventListener *listener, LLSD filter, const LLSD& userdata);
- // Removes a listener from this dispatcher
- void removeListener(LLEventListener *listener);
- // Gets a list of interested listeners
- std::vector<LLListenerEntry> getListeners() const;
- // Handle an event that has just been fired by communicating it
- // to listeners, passing it across a network, etc.
- bool fireEvent(LLPointer<LLEvent> event, LLSD filter);
- public:
- class Impl;
- private:
- Impl* impl;
- };
- // Interface for observable data (data that fires events)
- // In order for this class to work properly, it needs
- // an instance of an LLEventDispatcher to route events to their
- // listeners.
- class LL_COMMON_API LLObservable
- {
- public:
- // Initialize with the default Dispatcher
- LLObservable();
- virtual ~LLObservable();
- // Replaces the existing dispatcher pointer to the new one,
- // informing the dispatcher of the change.
- virtual bool setDispatcher(LLPointer<LLEventDispatcher> dispatcher);
- // Returns the current dispatcher pointer.
- virtual LLEventDispatcher* getDispatcher();
- void addListener(LLEventListener *listener, LLSD filter = "", const LLSD& userdata = "")
- {
- if (mDispatcher.notNull()) mDispatcher->addListener(listener, filter, userdata);
- }
- void removeListener(LLEventListener *listener)
- {
- if (mDispatcher.notNull()) mDispatcher->removeListener(listener);
- }
- // Notifies the dispatcher of an event being fired.
- void fireEvent(LLPointer<LLEvent> event, LLSD filter = LLSD());
- protected:
- LLPointer<LLEventDispatcher> mDispatcher;
- };
- class LLValueChangedEvent : public LLEvent
- {
- public:
- LLValueChangedEvent(LLObservable* source, LLSD value) : LLEvent(source, "value_changed"), mValue(value) { }
- LLSD getValue() { return mValue; }
- LLSD mValue;
- };
- } // LLOldEvents
- #endif // LL_EVENT_H