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path: root/indra/llcommon/llsingleton.h
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2019-08-20DRTVWR-493: Defend LL[Param]Singleton against ctor/init exceptions.Nat Goodspeed
An exception in the LLSingleton subclass constructor, or in its initSingleton() method, could leave the LLSingleton machinery in a bad state: the failing instance would remain in the MasterList, also on the stack of initializing LLSingletons. Catch exceptions in either and perform relevant cleanup. This problem is highlighted by test programs, in which LL_ERRS throws an exception rather than crashing the whole process. In the relevant catch clauses, clean up the initializing stack BEFORE logging. Otherwise we get tangled up recording bogus dependencies. Move capture_dependency() out of finishInitializing(): it must be called by every valid getInstance() call, both from LLSingleton and LLParamSingleton. Introduce new CONSTRUCTED EInitState value to distinguish "have called the constructor but not yet the initSingleton() method" from "currently within initSingleton() method." This is transient, but we execute the 'switch' on state within that moment. One could argue that the previous enum used INITIALIZING for current CONSTRUCTED, and INITIALIZED meant INITIALIZING too, but this is clearer. Introduce template LLSingletonBase::classname() helper methods to clarify verbose demangle(typeid(stuff).name()) calls. Similarly, introduce LLSingleton::pop_initializing() shorthand method.
2019-08-19DRTVWR-493: Improve exception safety of LLSingleton initialization.Nat Goodspeed
Add try/catch clauses to constructSingleton() (to catch exceptions in the subclass constructor) and finishInitializing() (to catch exceptions in the subclass initSingleton() method). Each of these catch clauses rethrows the exception -- they're for cleanup, not for ultimate handling. Introduce LLSingletonBase::reset_initializing(list_t::size_t). The idea is that since we can't know whether the exception happened before or after the push_initializing() call in LLSingletonBase's constructor, we can't just pop the stack. Instead, constructSingleton() captures the stack size before attempting to construct the new LLSingleton subclass. On exception, it calls reset_initializing() to restore the stack to that size. Naturally that requires a corresponding LLSingleton_manage_master method, whose MasterList specialization is a no-op. finishInitializing()'s exception handling is a bit simpler because it has a constructed LLSingleton subclass instance in hand, therefore push_initializing() has definitely been called, therefore it can call pop_initializing(). Break out new static capture_dependency() method from finishInitializing() because, in the previous LLSingleton::getInstance() implementation, the logic now wrapped in capture_dependency() was reached even in the INITIALIZED case. TODO: Add a new EInitState to differentiate "have been constructed, now calling initSingleton()" from "fully initialized, normal case" -- in the latter control path we should not be calling capture_dependency(). The LLSingleton_manage_master<LLSingletonBase::MasterList> specialization's get_initializing() function (which called get_initializing_from()) was potentially dangerous. get_initializing() is called by push_initializing(), which (in the general case) is called by LLSingletonBase's constructor. If somehow the MasterList's LLSingletonBase constructor ended up calling get_initializing(), it would have called get_initializing_from(), passing an LLSingletonBase which had not yet been constructed into the MasterList. In particular, its mInitializing map would not yet have been initialized at all. Since the MasterList must not, by design, depend on any other LLSingletons, LLSingleton_manage_master<LLSingletonBase::MasterList>::get_initializing() need not return a list from the official mInitializing map anyway. It can, and should, and now does, return a static dummy list. That obviates get_initializing_from(), which is removed. That in turn means we no longer need to pass get_initializing() an LLSingletonBase*. Remove that parameter.
2019-08-14DRTVWR-493: Work around static initialization order problem.Nat Goodspeed
LLParamSingleton contained a static member mutex. Unfortunately that wasn't guaranteed to be initialized by the time its getInstance() was entered. Use a function-local static instead.
2019-08-12DRTVWR-493: Rely on recursive_mutex to handle circularityNat Goodspeed
from LLParamSingleton::initSingleton().
2019-08-12Automated merge with ssh://bitbucket.org/andreykproductengine/drtvwr-493Nat Goodspeed
2019-08-12DRTVWR-493: Permit LLParamSingleton::initSingleton() circularity.Nat Goodspeed
This was forbidden, but AndreyK points out cases in which LLParamSingleton:: initSingleton() should in fact be allowed to circle back to its own instance() method. Use a recursive_mutex instead of plain mutex to permit that; remove LL_ERRS preventing it. Add LLParamSingleton::instance() method that calls LLParamSingleton::getInstance(). Inheriting LLSingleton::instance() called LLSingleton::getInstance() -- not at all what we want. Add LLParamSingleton unit tests.
2019-08-12DRTVWR-493 LLWearableType to LLParamSingletonandreykproductengine
2019-08-12DRTVWR-493: Streamline LLParamSingleton, LLLockedSingleton.Nat Goodspeed
Simplify LLSingleton::SingletonLifetimeManager to SingletonInitializer: that struct has not been responsible for deletion ever since LLSingletonBase acquired dependency-ordered deleteAll(). Move SingletonData::mInitState changes from SingletonLifetimeManager to constructSingleton() method. Similarly, constructSingleton() now sets SingletonData::mInstance instead of making its caller store the pointer. Add variadic arguments to LLSingleton::constructSingleton() so we can reuse it for LLParamSingleton. Add finishInitializing() method to encapsulate logic reused for getInstance()'s INITIALIZING and DELETED cases. Make LLParamSingleton a subclass of LLSingleton, just as LLLockedSingleton is a subclass of LLParamSingleton. Make LLParamSingleton a friend of LLSingleton, so it can access private members of LLSingleton without also granting access to any DERIVED_CLASS subclass. This eliminates the need for protected getInitState(). LLParamSingleton::initParamSingleton() reuses LLSingleton::constructSingleton() and finishInitializing(). Its getInstance() method completely replaces LLSingleton::getInstance(): in most EInitStates, LLParamSingleton::getInstance() is an error. Use a std::mutex to serialize calls to LLParamSingleton::initParamSingleton() and getInstance(). While LLSingleton::getInstance() relies on the "initialized exactly once" guarantee for block-scope static declarations, LLParamSingleton cannot rely on the same mechanism. LLLockedSingleton is now a very succinct subclass of LLParamSingleton -- they have very similar functionality. Giving the LLSINGLETON() macro variadic arguments eliminates the need for a separate LLPARAMSINGLETON() macro, while continuing to support existing usage.
2019-07-25DRTVWR-493 LLImage to LLParamSingletonandreykproductengine
2017-04-24DRTVWR-418: Remove final shutdown cleanup as a cause of crashes.Nat Goodspeed
The recent LLSingleton work added a hook that would run during the C++ runtime's final destruction of static objects. When the LAST LLSingleton in any module was destroyed, its destructor would call LLSingletonBase::deleteAll(). That mechanism was intended to permit an application consuming LLSingletons to skip making an explicit deleteAll() call, knowing that all instantiated LLSingleton instances would eventually be cleaned up anyway. However -- experience proves that kicking off deleteAll() processing during the C++ runtime's final cleanup is too late. Too much has already been destroyed. That call tends to cause more shutdown crashes than it resolves. This commit deletes that whole mechanism. Going forward, if you want to clean up LLSingleton instances, you must explicitly call LLSingletonBase::deleteAll() during the application lifetime. If you don't, LLSingleton instances will simply be leaked -- which might be okay, considering the application is terminating anyway.
2017-03-13DRTVWR-418: Ignore logging that requires resurrecting singletons.Nat Goodspeed
The logging subsystem depends on two different LLSingletons for some reason. It turns out to be very difficult to completely avoid executing any logging calls after the LLSingletonBase::deleteAll(), but we really don't want to resurrect those LLSingletons so late in the run for a couple stragglers. Introduce LLSingleton::wasDeleted() query method, and use it in logging subsystem to simply bypass last-millisecond logging requests.
2016-09-15MAINT-5232: Normalize LLSingleton subclasses.Nat Goodspeed
A shocking number of LLSingleton subclasses had public constructors -- and in several instances, were being explicitly instantiated independently of the LLSingleton machinery. This breaks the new LLSingleton dependency-tracking machinery. It seems only fair that if you say you want an LLSingleton, there should only be ONE INSTANCE! Introduce LLSINGLETON() and LLSINGLETON_EMPTY_CTOR() macros. These handle the friend class LLSingleton<whatevah>; and explicitly declare a private nullary constructor. To try to enforce the LLSINGLETON() convention, introduce a new pure virtual LLSingleton method you_must_use_LLSINGLETON_macro() which is, as you might suspect, defined by the macro. If you declare an LLSingleton subclass without using LLSINGLETON() or LLSINGLETON_EMPTY_CTOR() in the class body, you can't instantiate the subclass for lack of a you_must_use_LLSINGLETON_macro() implementation -- which will hopefully remind the coder. Trawl through ALL LLSingleton subclass definitions, sprinkling in LLSINGLETON() or LLSINGLETON_EMPTY_CTOR() as appropriate. Remove all explicit constructor declarations, public or private, along with relevant 'friend class LLSingleton<myself>' declarations. Where destructors are declared, move them into private section as well. Where the constructor was inline but nontrivial, move out of class body. Fix several LLSingleton abuses revealed by making ctors/dtors private: LLGlobalEconomy was both an LLSingleton and the base class for LLRegionEconomy, a non-LLSingleton. (Therefore every LLRegionEconomy instance contained another instance of the LLGlobalEconomy "singleton.") Extract LLBaseEconomy; LLGlobalEconomy is now a trivial subclass of that. LLRegionEconomy, as you might suspect, now derives from LLBaseEconomy. LLToolGrab, an LLSingleton, was also explicitly instantiated by LLToolCompGun's constructor. Extract LLToolGrabBase, explicitly instantiated, with trivial subclass LLToolGrab, the LLSingleton instance. (WARNING: LLToolGrabBase methods have an unnerving tendency to go after LLToolGrab::getInstance(). I DO NOT KNOW what should be the relationship between the instance in LLToolCompGun and the LLToolGrab singleton instance.) LLGridManager declared a variant constructor accepting (const std::string&), with the comment: // initialize with an explicity grid file for testing. As there is no evidence of this being called from anywhere, delete it. LLChicletBar's constructor accepted an optional (const LLSD&). As the LLSD parameter wasn't used, and as there is no evidence of it being passed from anywhere, delete the parameter. LLViewerWindow::shutdownViews() was checking LLNavigationBar:: instanceExists(), then deleting its getInstance() pointer -- leaving a dangling LLSingleton instance pointer, a land mine if any subsequent code should attempt to reference it. Use deleteSingleton() instead. ~LLAppViewer() was calling LLViewerEventRecorder::instance() and then explicitly calling ~LLViewerEventRecorder() on that instance -- leaving the LLSingleton instance pointer pointing to an allocated-but-destroyed instance. Use deleteSingleton() instead.
2016-09-06MAINT-5232: Make LLSingleton's 'initializing' stack coro-specific.Nat Goodspeed
The stack we maintain of which LLSingletons are currently initializing only makes sense when associated with a particular C++ call stack. But each coroutine introduces another C++ call stack! Move the initializing stack from function-static storage to LLSingletonBase::MasterList. Make it a map keyed by llcoro::id. Each coro then has a stack of its own. This introduces more dependencies on the MasterList singleton, requiring additional LLSingleton_manage_master workarounds.
2016-09-03MAINT-5232: Add DEBUG logging to LLSingleton dependency tracking.Nat Goodspeed
Specifically, add DEBUG logging to the code that maintains the stack of LLSingletons currently being initialized. This involves passing LLSingletonBase's constructor the name of LLSingleton's template parameter subclass, since during that constructor typeid(*this).name() will only produce "LLSingletonBase". Also add logdebugs() and oktolog() helper functions.
2016-08-30Automated merge with ssh://bitbucket.org/lindenlab/viewer-releaseNat Goodspeed
2015-11-10remove execute permission from many files that should not have itOz Linden
2015-06-30MAINT-5232: Add tests for new LLSingleton dependency functionality.Nat Goodspeed
2015-06-26MAINT-5232: Use LLError::Log::demangle() to log LLSingleton classes.Nat Goodspeed
2015-06-26MAINT-5232: Loosen LLSingleton circularity constraints slightly.Nat Goodspeed
LLSingleton explicitly supports circular dependencies: initialization performed during an LLSingleton subclass's initSingleton() method may recursively call that same subclass's getInstance() method. On the other hand, circularity from a subclass constructor cannot be permitted, else getInstance() would have to return a partially-constructed object. Our dependency tracking circularity check initially forbade both. Loosen it to permit references from within initSingleton().
2015-06-25MAINT-5232: Correct forward declaration of LLSingleton_manage_master.Nat Goodspeed
The forward declaration said it was a 'friend class', whereas the actual definition is a struct. MSVC dislikes that.
2015-06-25MAINT-5232: Try to avoid circularity between LLError and LLSingleton.Nat Goodspeed
Part of LLError's logging infrastructure is implemented with an LLSingleton. Therefore, attempts to log from within LLSingleton machinery could potentially go south if LLError's LLSingleton is not yet initialized. Introduce LLError::is_available() in llerrorcontrol.h and llerror.cpp. Make LLSingletonBase::logwarns() and logerrs() consult LLError::is_available() before attempting to use LL_WARNS or LL_ERRS, respectively. Moreover, make all LLSingleton internal logging use logwarns() and logerrs() instead of directly engaging LL_ERRS or LL_WARNS.
2015-06-24MAINT-5232: Introduce inter-LLSingleton dependency tracking.Nat Goodspeed
Introduce LLSingleton::cleanupSingleton() canonical method as the place to put any subclass cleanup logic that might take nontrivial realtime or throw an exception. Neither is appropriate in a destructor. Track all extant LLSingleton subclass instances on a master list, which permits adding LLSingletonBase::cleanupAll() and deleteAll() methods. Also notice when any LLSingleton subclass constructor (or initSingleton() method) calls instance() or getInstance() for another LLSingleton, and capture that other LLSingleton instance as a dependency of the first. This permits cleanupAll() and deleteAll() to perform a dependency sort on the master list, thus cleaning up (or deleting) leaf LLSingletons AFTER the LLSingletons that depend on them. Make C++ runtime's final static destructor call LLSingletonBase::deleteAll() instead of deleting individual LLSingleton instances in arbitrary order. Eliminate "llerror.h" from llsingleton.h, a longstanding TODO.
2015-05-28MAINT-5232: Stop documenting deprecated alternative LLSingleton usage.Nat Goodspeed
2015-05-22MAINT-5232: Clean up some dubious LLSingleton methods.Nat Goodspeed
Remove evil getIfExists() method, used by no one. Remove evil destroyed() method, used in exactly three places -- one of which is a test. Replace with equally evil instanceExists() method, which is used EVERYWHERE -- sigh.
2013-08-09second phase summer cleaningRichard Linden
replace llinfos, lldebugs, etc with new LL_INFOS(), LL_DEBUGS(), etc.
2013-06-05merge with viewer-releaseRichard Linden
2013-05-20BUILDFIX: mac gcc fixRichard Linden
2013-05-02SH-4080 WIP interesting: random crash on MacRichard Linden
added comments to llsingleton.h
2013-04-29SH-4080 WIP interesting: random crash on MacRichard Linden
fixed singleton unit test resurrecting a singleton now properly calls initSingleton()
2013-04-27SH-4080 WIP interesting: random crash on MacRichard Linden
more singleton cleanup to eliminate crashes on startup/exit
2013-04-26SH-4080 WIP interesting: random crash on MacRichard Linden
fixed Mac crash related to non-reentrant singleton constructor
2013-04-26SH-4080 WIP interesting: random crash on MacRichard Linden
fixed Mac crash related to non-reentrant singleton constructor
2013-04-24BUILDFIX: singleton unit test could not resurrect singletonRichard Linden
2013-04-24BUILDFIX: method name was wrongRichard Linden
2013-04-24SH-4080 WIP interesting: random crash on MacRichard Linden
potential fix for crasher cleaned up llsingleton
2013-03-29Update Mac and Windows breakpad builds to latestGraham Madarasz
2013-01-03SH-3406 WIP convert fast timers to lltrace systemRichard Linden
made fast timer stack thread local added LLThreadLocalSingleton made LLThreadLocalPointer obey pointer rules for const added LLThreadLocalSingletonPointer for fast thread local pointers
2011-09-06LLProxy code review fixes.Logan Dethrow
* Removed check_curl_code and check_curl_multi_code from the global namespace. * Added comments documenting which thread the public methods of LLProxy should be called from. * Corrected grammar in LLSingleton.h * Fixed a buffer scope problem in llpacketring.cpp.
2011-09-01Clarified the reason for adding the deleteSingleton method to LLSingleton. ↵Logan Dethrow
Added a simple unit test to verify the functionality of the deleteSingleton method.
2011-07-21STORM-1112 Protected LLProxy members during cross-thread calls to ↵Logan Dethrow
LLProxy::applyProxySettings()
2010-08-13Change license from GPL to LGPL (version 2.1)Oz Linden
2009-11-30Linker optimization - use "extern template" for commonly regenerated templatesJames Cook
Also replaced many duplicate calls to LLViewerCamera::getInstance() with local pointer. Reviewed with Ambroff
2009-08-06Add on-demand allocation of LLSingletonRegistry::sSingletonMap so we don't ↵brad kittenbrink
rely on static initialization order. reviewed by nat.
2009-08-05Merged in my DEV-35401 "doubleton" fix.brad kittenbrink
2009-08-05Attemt at fixing "doubleton" problems across shared lib boundaries. ↵brad kittenbrink
Singletons now keep their SingletonInstaceData in a big global map in the llcommon module.
2009-08-04svn merge -r 128442:129343 ↵Richard Nelson
svn+ssh://svn.lindenlab.com/svn/linden/branches/skinning/skinning-18 into svn+ssh://svn.lindenlab.com/svn/linden/branches/viewer/viewer-2.0.0-3
2009-06-21merge -r 122421-124917 viewer-2.0.0-2 -> viewer-2.0.0-3Steven Bennetts
ignore-dead-branch