From af4fbc1f8a99a3c5370cb6db45435e67f9ce92d2 Mon Sep 17 00:00:00 2001 From: Nat Goodspeed Date: Sat, 18 Jun 2022 11:57:10 -0400 Subject: DRTVWR-564: WIP: Add LazyEventAPI and tests. Tests don't yet pass. LazyEventAPI is a registrar that implicitly instantiates some particular LLEventAPI subclass on demand: that is, when LLEventPumps::obtain() tries to find an LLEventPump by the registered name. This leverages the new LLEventPumps::registerPumpFactory() machinery. Fix registerPumpFactory() to adapt the passed PumpFactory to accept TypeFactory parameters (two of which it ignores). Supplement it with unregisterPumpFactory() to support LazyEventAPI instances with lifespans shorter than the process -- which may be mostly test programs, but still a hole worth closing. Similarly, add unregisterTypeFactory(). A LazyEventAPI subclass takes over responsibility for specifying the LLEventAPI's name, desc, field, plus whatever add() calls will be needed to register the LLEventAPI's operations. This is so we can (later) enhance LLLeapListener to consult LazyEventAPI instances for not-yet-instantiated LLEventAPI metadata, as well as enumerating existing LLEventAPI instances. The trickiest part of this is capturing calls to the various LLEventDispatcher::add() overloads in such a way that, when the LLEventAPI subclass is eventually instantiated, we can replay them in the new instance. LLEventAPI acquires a new protected constructor specifically for use by a subclass registered by a companion LazyEventAPI. It accepts a const reference to LazyEventAPIParams, intended to be opaque to the LLEventAPI subclass; the subclass must declare a constructor that accepts and forwards the parameter block to the new LLEventAPI constructor. The implementation delegates to the existing LLEventAPI constructor, plus it runs deferred add() calls. LLDispatchListener now derives from LLEventStream instead of containing it as a data member. The reason is that if LLEventPumps::obtain() implicitly instantiates it, LLEventPumps's destructor will try to destroy it by deleting the LLEventPump*. If the LLEventPump returned by the factory function is a data member of an outer class, that won't work so well. But if LLDispatchListener (and by implication, LLEventAPI and any subclass) is derived from LLEventPump, then the virtual destructor will Do The Right Thing. Change LLDispatchListener to *not* allow tweaking the LLEventPump name. Since the overwhelming use case for LLDispatchListener is LLEventAPI, accepting but silently renaming an LLEventAPI subclass would ensure nobody could reach it. Change LLEventDispatcher's use of std::enable_if to control the set of add() overloads available for the intended use cases. Apparently this formulation is just as functional at the method declaration point, while avoiding the need to restate the whole enable_if expression at the method definition point. Add lazyeventapi_test.cpp to exercise. --- indra/llcommon/lazyeventapi.cpp | 53 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 indra/llcommon/lazyeventapi.cpp (limited to 'indra/llcommon/lazyeventapi.cpp') diff --git a/indra/llcommon/lazyeventapi.cpp b/indra/llcommon/lazyeventapi.cpp new file mode 100644 index 0000000000..aefc2db6da --- /dev/null +++ b/indra/llcommon/lazyeventapi.cpp @@ -0,0 +1,53 @@ +/** + * @file lazyeventapi.cpp + * @author Nat Goodspeed + * @date 2022-06-17 + * @brief Implementation for lazyeventapi. + * + * $LicenseInfo:firstyear=2022&license=viewerlgpl$ + * Copyright (c) 2022, Linden Research, Inc. + * $/LicenseInfo$ + */ + +// Precompiled header +#include "linden_common.h" +// associated header +#include "lazyeventapi.h" +// STL headers +// std headers +// external library headers +// other Linden headers +#include "llevents.h" + +LL::LazyEventAPIBase::LazyEventAPIBase( + const std::string& name, const std::string& desc, const std::string& field) +{ + // populate embedded LazyEventAPIParams instance + mParams.name = name; + mParams.desc = desc; + mParams.field = field; + // mParams.init and mOperations are populated by subsequent add() calls. + + // Our raison d'etre: register as an LLEventPumps::PumpFactory + // so obtain() will notice any request for this name and call us. + // Of course, our subclass constructor must finish running (making add() + // calls) before mParams will be fully populated, but we expect that to + // happen well before the first LLEventPumps::obtain(name) call. + mRegistered = LLEventPumps::instance().registerPumpFactory( + name, + [this](const std::string& name){ return construct(name); }); +} + +LL::LazyEventAPIBase::~LazyEventAPIBase() +{ + // If our constructor's registerPumpFactory() call was unsuccessful, that + // probably means somebody else claimed the name first. If that's the + // case, do NOT unregister their name out from under them! + // If this is a static instance being destroyed at process shutdown, + // LLEventPumps will probably have been cleaned up already. + if (mRegistered && ! LLEventPumps::wasDeleted()) + { + // unregister the callback to this doomed instance + LLEventPumps::instance().unregisterPumpFactory(mParams.name); + } +} -- cgit v1.2.3 From 6b53036f7499a4e42813378009050eaf02c0b69d Mon Sep 17 00:00:00 2001 From: Nat Goodspeed Date: Wed, 22 Jun 2022 10:51:11 -0400 Subject: DRTVWR-564: Allow LLLeapListener to report LazyEventAPIs too. One important factor in the design of LazyEventAPI was the desire to allow LLLeapListener to query metadata for an LLEventAPI even if it hasn't yet been instantiated by LazyEventAPI. That's why LazyEventAPI requires the same metadata required by a classic LLEventAPI. Instead of just publicly exposing its data members, give LazyEventAPI a query API mimicking LLEventAPI / LLEventDispatcher. Protect data members and private methods. Adapt lazyeventapi_test.cpp accordingly. Extend LLLeapListener::getAPIs() and getAPI() to look through LazyEventAPIBase instances after first checking existing LLEventAPI instances. Because the query API for LazyEventAPIBase mimics LLEventAPI's, extract getAPI()'s actual metadata reporting to a new internal template function reportAPI(). While we're touching LLLeapListener, we no longer need BOOST_FOREACH(). --- indra/llcommon/lazyeventapi.cpp | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'indra/llcommon/lazyeventapi.cpp') diff --git a/indra/llcommon/lazyeventapi.cpp b/indra/llcommon/lazyeventapi.cpp index aefc2db6da..028af9f33f 100644 --- a/indra/llcommon/lazyeventapi.cpp +++ b/indra/llcommon/lazyeventapi.cpp @@ -15,9 +15,11 @@ #include "lazyeventapi.h" // STL headers // std headers +#include // std::find_if // external library headers // other Linden headers #include "llevents.h" +#include "llsdutil.h" LL::LazyEventAPIBase::LazyEventAPIBase( const std::string& name, const std::string& desc, const std::string& field) @@ -51,3 +53,20 @@ LL::LazyEventAPIBase::~LazyEventAPIBase() LLEventPumps::instance().unregisterPumpFactory(mParams.name); } } + +LLSD LL::LazyEventAPIBase::getMetadata(const std::string& name) const +{ + // Since mOperations is a vector rather than a map, just search. + auto found = std::find_if(mOperations.begin(), mOperations.end(), + [&name](const auto& namedesc) + { return (namedesc.first == name); }); + if (found == mOperations.end()) + return {}; + + // LLEventDispatcher() supplements the returned metadata in different + // ways, depending on metadata provided to the specific add() method. + // Don't try to emulate all that. At some point we might consider more + // closely unifying LLEventDispatcher machinery with LazyEventAPI, but for + // now this will have to do. + return llsd::map("name", found->first, "desc", found->second); +} -- cgit v1.2.3