diff options
Diffstat (limited to 'indra/llcommon/llcoros.cpp')
| -rwxr-xr-x | indra/llcommon/llcoros.cpp | 86 |
1 files changed, 79 insertions, 7 deletions
diff --git a/indra/llcommon/llcoros.cpp b/indra/llcommon/llcoros.cpp index baaddcaed1..2d0c419ae0 100755 --- a/indra/llcommon/llcoros.cpp +++ b/indra/llcommon/llcoros.cpp @@ -34,11 +34,65 @@ // std headers // external library headers #include <boost/bind.hpp> +#include <boost/thread/tss.hpp> // other Linden headers #include "llevents.h" #include "llerror.h" #include "stringize.h" +namespace { + +// do nothing, when we need nothing done +void no_cleanup(LLCoros::coro::self*) {} + +// When the dcoroutine library calls a top-level callable, it implicitly +// passes coro::self& as the first parameter. All our consumer code used to +// explicitly pass coro::self& down through all levels of call stack, because +// at the leaf level we need it for context-switching. But since coroutines +// are based on cooperative switching, we can cause the top-level entry point +// to stash a static pointer to the currently-running coroutine, and manage it +// appropriately as we switch out and back in. That eliminates the need to +// pass it as an explicit parameter down through every level, which is +// unfortunately viral in nature. Finding it implicitly rather than explicitly +// allows minor maintenance in which a leaf-level function adds a new async +// I/O call that suspends the calling coroutine, WITHOUT having to propagate +// coro::self& through every function signature down to that point -- and of +// course through every other caller of every such function. +// We use a boost::thread_specific_ptr because each thread potentially has its +// own distinct pool of coroutines. +// This thread_specific_ptr does NOT own the 'self' object! It merely +// identifies it. For this reason we instantiate it with a no-op cleanup +// function. +static boost::thread_specific_ptr<LLCoros::coro::self> +sCurrentSelf(no_cleanup); + +} // anonymous + +//static +LLCoros::coro::self& LLCoros::get_self() +{ + coro::self* current_self = sCurrentSelf.get(); + if (! current_self) + { + LL_ERRS("LLCoros") << "Calling get_self() from non-coroutine context!" << LL_ENDL; + } + return *current_self; +} + +LLCoros::Suspending::Suspending(): + mSuspended(sCurrentSelf.get()) +{ + // For the duration of our time away from this coroutine, sCurrentSelf + // must NOT refer to this coroutine. + sCurrentSelf.reset(); +} + +LLCoros::Suspending::~Suspending() +{ + // Okay, we're back, reinstate previous value of sCurrentSelf. + sCurrentSelf.reset(mSuspended); +} + LLCoros::LLCoros(): // MAINT-2724: default coroutine stack size too small on Windows. // Previously we used @@ -60,7 +114,7 @@ bool LLCoros::cleanup(const LLSD&) // since last tick? if (mi->second->exited()) { - LL_INFOS("LLCoros") << "LLCoros: cleaning up coroutine " << mi->first << LL_ENDL; + LL_INFOS("LLCoros") << "LLCoros: cleaning up coroutine " << mi->first << LL_ENDL; // The erase() call will invalidate its passed iterator value -- // so increment mi FIRST -- but pass its original value to // erase(). This is what postincrement is all about. @@ -94,7 +148,7 @@ std::string LLCoros::generateDistinctName(const std::string& prefix) const { if (mCoros.find(name) == mCoros.end()) { - LL_INFOS("LLCoros") << "LLCoros: launching coroutine " << name << LL_ENDL; + LL_INFOS("LLCoros") << "LLCoros: launching coroutine " << name << LL_ENDL; return name; } } @@ -114,10 +168,10 @@ bool LLCoros::kill(const std::string& name) return true; } -std::string LLCoros::getNameByID(const void* self_id) const +std::string LLCoros::getName() const { - // Walk the existing coroutines, looking for one from which the 'self_id' - // passed to us comes. + // Walk the existing coroutines, looking for the current one. + void* self_id = get_self().get_id(); for (CoroMap::const_iterator mi(mCoros.begin()), mend(mCoros.end()); mi != mend; ++mi) { namespace coro_private = boost::dcoroutines::detail; @@ -136,10 +190,24 @@ void LLCoros::setStackSize(S32 stacksize) mStackSize = stacksize; } +namespace { + +// Top-level wrapper around caller's coroutine callable. This function accepts +// the coroutine library's implicit coro::self& parameter and sets sCurrentSelf +// but does not pass it down to the caller's callable. +void toplevel(LLCoros::coro::self& self, const LLCoros::callable_t& callable) +{ + sCurrentSelf.reset(&self); + callable(); + sCurrentSelf.reset(); +} + +} // anonymous + /***************************************************************************** * MUST BE LAST *****************************************************************************/ -// Turn off MSVC optimizations for just LLCoros::launchImpl() -- see +// Turn off MSVC optimizations for just LLCoros::launch() -- see // DEV-32777. But MSVC doesn't support push/pop for optimization flags as it // does for warning suppression, and we really don't want to force // optimization ON for other code even in Debug or RelWithDebInfo builds. @@ -150,9 +218,13 @@ void LLCoros::setStackSize(S32 stacksize) #pragma optimize("", off) #endif // LL_MSVC -std::string LLCoros::launchImpl(const std::string& prefix, coro* newCoro) +std::string LLCoros::launch(const std::string& prefix, const callable_t& callable) { std::string name(generateDistinctName(prefix)); + // Wrap the caller's callable in our toplevel() function so we can manage + // sCurrentSelf appropriately at startup and shutdown of each coroutine. + coro* newCoro = new coro(boost::bind(toplevel, _1, callable), mStackSize); + // Store it in our pointer map mCoros.insert(name, newCoro); /* Run the coroutine until its first wait, then return here */ (*newCoro)(std::nothrow); |