diff options
Diffstat (limited to 'indra/llcommon/llevents.h')
| -rw-r--r-- | indra/llcommon/llevents.h | 97 |
1 files changed, 85 insertions, 12 deletions
diff --git a/indra/llcommon/llevents.h b/indra/llcommon/llevents.h index f52cf33fd8..a73ada2931 100644 --- a/indra/llcommon/llevents.h +++ b/indra/llcommon/llevents.h @@ -44,6 +44,7 @@ #include "llsd.h" #include "llsingleton.h" #include "lldependencies.h" +#include "ll_template_cast.h" /*==========================================================================*| // override this to allow binding free functions with more parameters @@ -256,6 +257,11 @@ namespace LLEventDetail /// signature. typedef boost::function<LLBoundListener(const LLEventListener&)> ConnectFunc; + /// overload of visit_and_connect() when we have a string identifier available + template <typename LISTENER> + LLBoundListener visit_and_connect(const std::string& name, + const LISTENER& listener, + const ConnectFunc& connect_func); /** * Utility template function to use Visitor appropriately * @@ -266,7 +272,10 @@ namespace LLEventDetail */ template <typename LISTENER> LLBoundListener visit_and_connect(const LISTENER& listener, - const ConnectFunc& connect_func); + const ConnectFunc& connect_func) + { + return visit_and_connect("", listener, connect_func); + } } // namespace LLEventDetail /***************************************************************************** @@ -468,7 +477,8 @@ public: // This is why listen() is a template. Conversion from boost::bind() // to LLEventListener performs type erasure, so it's important to look // at the boost::bind object itself before that happens. - return LLEventDetail::visit_and_connect(listener, + return LLEventDetail::visit_and_connect(name, + listener, boost::bind(&LLEventPump::listen_impl, this, name, @@ -522,7 +532,7 @@ private: protected: /// implement the dispatching - boost::scoped_ptr<LLStandardSignal> mSignal; + boost::shared_ptr<LLStandardSignal> mSignal; /// valve open? bool mEnabled; @@ -664,6 +674,62 @@ private: LLSD mReqid; }; +/** + * Base class for LLListenerWrapper. See visit_and_connect() and llwrap(). We + * provide virtual @c accept_xxx() methods, customization points allowing a + * subclass access to certain data visible at LLEventPump::listen() time. + * Example subclass usage: + * + * @code + * myEventPump.listen("somename", + * llwrap<MyListenerWrapper>(boost::bind(&MyClass::method, instance, _1))); + * @endcode + * + * Because of the anticipated usage (note the anonymous temporary + * MyListenerWrapper instance in the example above), the @c accept_xxx() + * methods must be @c const. + */ +class LL_COMMON_API LLListenerWrapperBase +{ +public: + /// New instance. The accept_xxx() machinery makes it important to use + /// shared_ptrs for our data. Many copies of this object are made before + /// the instance that actually ends up in the signal, yet accept_xxx() + /// will later be called on the @em original instance. All copies of the + /// same original instance must share the same data. + LLListenerWrapperBase(): + mName(new std::string), + mConnection(new LLBoundListener) + { + } + + /// Copy constructor. Copy shared_ptrs to original instance data. + LLListenerWrapperBase(const LLListenerWrapperBase& that): + mName(that.mName), + mConnection(that.mConnection) + { + } + virtual ~LLListenerWrapperBase() {} + + /// Ask LLEventPump::listen() for the listener name + virtual void accept_name(const std::string& name) const + { + *mName = name; + } + + /// Ask LLEventPump::listen() for the new connection + virtual void accept_connection(const LLBoundListener& connection) const + { + *mConnection = connection; + } + +protected: + /// Listener name. + boost::shared_ptr<std::string> mName; + /// Connection. + boost::shared_ptr<LLBoundListener> mConnection; +}; + /***************************************************************************** * Underpinnings *****************************************************************************/ @@ -898,7 +964,8 @@ namespace LLEventDetail * LLStandardSignal, returning LLBoundListener. */ template <typename LISTENER> - LLBoundListener visit_and_connect(const LISTENER& raw_listener, + LLBoundListener visit_and_connect(const std::string& name, + const LISTENER& raw_listener, const ConnectFunc& connect_func) { // Capture the listener @@ -913,14 +980,20 @@ namespace LLEventDetail // which type details have been erased. unwrap() comes from // Boost.Signals, in case we were passed a boost::ref(). visit_each(visitor, LLEventDetail::unwrap(raw_listener)); - // Make the connection using passed function. At present, wrapping - // this functionality into this function is a bit silly: we don't - // really need a visit_and_connect() function any more, just a visit() - // function. The definition of this function dates from when, after - // visit_each(), after establishing the connection, we had to - // postprocess the new connection with the visitor object. That's no - // longer necessary. - return connect_func(listener); + // Make the connection using passed function. + LLBoundListener connection(connect_func(listener)); + // If the LISTENER is an LLListenerWrapperBase subclass, pass it the + // desired information. It's important that we pass the raw_listener + // so the compiler can make decisions based on its original type. + const LLListenerWrapperBase* lwb = + ll_template_cast<const LLListenerWrapperBase*>(&raw_listener); + if (lwb) + { + lwb->accept_name(name); + lwb->accept_connection(connection); + } + // In any case, show new connection to caller. + return connection; } } // namespace LLEventDetail |