SL-793: Add LLEventPumps::clear() method to disconnect all listeners.

This is like the existing reset() method, except that reset() is specifically
intended for shutdown: it disables every existing LLEventPump in such a way
that it cannot be subsequently reused. (The original idea was to disconnect
listeners in DLLs unloaded at shutdown.)

clear() forcibly disconnects all existing listeners, but leaves LLEventPumps
ready for reuse. This is useful (e.g.) for test programs to reset the state of
LLEventPumps between individual test functions.

indra/llcommon/llevents.cpp

@@ -45,6 +45,7 @@
 #include <cctype>
 // external library headers
 #include <boost/range/iterator_range.hpp>
+#include <boost/make_shared.hpp>
 #if LL_WINDOWS
 #pragma warning (push)
 #pragma warning (disable : 4701) // compiler thinks might use uninitialized var, but no
@@ -154,13 +155,23 @@ void LLEventPumps::flush()
     }
 }
 
+void LLEventPumps::clear()
+{
+    // Clear every known LLEventPump instance. Leave it up to each instance to
+    // decide what to do with the clear() call.
+    for (PumpMap::value_type& pair : mPumpMap)
+    {
+        pair.second->clear();
+    }
+}
+
 void LLEventPumps::reset()
 {
     // Reset every known LLEventPump instance. Leave it up to each instance to
     // decide what to do with the reset() call.
-    for (PumpMap::iterator pmi = mPumpMap.begin(), pmend = mPumpMap.end(); pmi != pmend; ++pmi)
+    for (PumpMap::value_type& pair : mPumpMap)
     {
-        pmi->second->reset();
+        pair.second->reset();
     }
 }
 
@@ -283,7 +294,7 @@ LLEventPump::LLEventPump(const std::string& name, bool tweak):
     // Register every new instance with LLEventPumps
     mRegistry(LLEventPumps::instance().getHandle()),
     mName(mRegistry.get()->registerNew(*this, name, tweak)),
-    mSignal(new LLStandardSignal()),
+    mSignal(boost::make_shared<LLStandardSignal>()),
     mEnabled(true)
 {}
 
@@ -311,6 +322,14 @@ std::string LLEventPump::inventName(const std::string& pfx)
     return STRINGIZE(pfx << suffix++);
 }
 
+void LLEventPump::clear()
+{
+    // Destroy the original LLStandardSignal instance, replacing it with a
+    // whole new one.
+    mSignal = boost::make_shared<LLStandardSignal>();
+    mConnections.clear();
+}
+
 void LLEventPump::reset()
 {
     mSignal.reset();
@@ -546,16 +565,16 @@ bool LLEventStream::post(const LLSD& event)
 bool LLEventMailDrop::post(const LLSD& event)
 {
     bool posted = false;
-    
+
     if (!mSignal->empty())
         posted = LLEventStream::post(event);
-    
+
     if (!posted)
     {   // if the event was not handled we will save it for later so that it can 
         // be posted to any future listeners when they attach.
         mEventHistory.push_back(event);
     }
-    
+
     return posted;
 }
 

indra/llcommon/llevents.h

@@ -263,6 +263,11 @@ public:
      */
     void flush();
 
+    /**
+     * Disconnect listeners from all known LLEventPump instances
+     */
+    void clear();
+
     /**
      * Reset all known LLEventPump instances
      * workaround for DEV-35406 crash on shutdown
@@ -586,7 +591,7 @@ private:
     friend class LLEventPumps;
     /// flush queued events
     virtual void flush() {}
-
+    virtual void clear();
     virtual void reset();