From ec6487f3a70a5067f6d8fc601437160bb4fa753f Mon Sep 17 00:00:00 2001 From: Nat Goodspeed Date: Thu, 27 Sep 2018 14:57:03 -0400 Subject: DRTVWR-474: Make LLEventMailDrop pass all saved events to listener. Previously, LLEventMailDrop would send only the first queued event to a newly-connected listener. If you wanted to flush all queued events, you'd have to "pump" the queue by repeatedly disconnecting and reconnecting -- with no good way to know when you'd caught up. The new behavior makes LLEventMailDrop resemble a multi-valued future: a rendezvous between producer and consumer that, once connected, pushes values rather than requiring them to be pulled (as with a simple queue) -- regardless of the relative order in which post() and listen() are called. --- indra/llcommon/llevents.cpp | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-) (limited to 'indra/llcommon/llevents.cpp') diff --git a/indra/llcommon/llevents.cpp b/indra/llcommon/llevents.cpp index dce97b5411..eedd8c92b5 100644 --- a/indra/llcommon/llevents.cpp +++ b/indra/llcommon/llevents.cpp @@ -545,10 +545,8 @@ bool LLEventStream::post(const LLSD& event) *****************************************************************************/ bool LLEventMailDrop::post(const LLSD& event) { - bool posted = false; - - if (!mSignal->empty()) - posted = LLEventStream::post(event); + // forward the call to our base class + bool posted = LLEventStream::post(event); if (!posted) { // if the event was not handled we will save it for later so that it can @@ -564,16 +562,25 @@ LLBoundListener LLEventMailDrop::listen_impl(const std::string& name, const NameList& after, const NameList& before) { - if (!mEventHistory.empty()) + // Before actually connecting this listener for subsequent post() calls, + // first feed each of the saved events, in order, to the new listener. + // Remove any that this listener consumes -- Effective STL, Item 9. + for (auto hi(mEventHistory.begin()), hend(mEventHistory.end()); hi != hend; ) { - if (listener(mEventHistory.front())) + if (listener(*hi)) { - mEventHistory.pop_front(); + // new listener consumed this event, erase it + hi = mEventHistory.erase(hi); + } + else + { + // listener did not consume this event, just move along + ++hi; } } + // let base class perform the actual connection return LLEventStream::listen_impl(name, listener, after, before); - } -- cgit v1.2.3