401 lines
13 KiB
C++
401 lines
13 KiB
C++
/**
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* @file llcoros.cpp
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* @author Nat Goodspeed
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* @date 2009-06-03
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* @brief Implementation for llcoros.
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*
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* $LicenseInfo:firstyear=2009&license=viewerlgpl$
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* Second Life Viewer Source Code
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* Copyright (C) 2010, Linden Research, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation;
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* version 2.1 of the License only.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
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* $/LicenseInfo$
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*/
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// Precompiled header
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#include "linden_common.h"
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// associated header
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#include "llcoros.h"
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// STL headers
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// std headers
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// external library headers
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#include <boost/bind.hpp>
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// other Linden headers
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#include "llevents.h"
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#include "llerror.h"
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#include "stringize.h"
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#include "llexception.h"
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#if LL_WINDOWS
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#include <excpt.h>
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#endif
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namespace {
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void no_op() {}
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} // anonymous namespace
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// Do nothing, when we need nothing done. This is a static member of LLCoros
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// because CoroData is a private nested class.
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void LLCoros::no_cleanup(CoroData*) {}
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// CoroData for the currently-running coroutine. Use a thread_specific_ptr
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// because each thread potentially has its own distinct pool of coroutines.
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LLCoros::Current::Current()
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{
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// Use a function-static instance so this thread_specific_ptr is
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// instantiated on demand. Since we happen to know it's consumed by
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// LLSingleton, this is likely to happen before the runtime has finished
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// initializing module-static data. For the same reason, we can't package
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// this pointer in an LLSingleton.
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// This thread_specific_ptr does NOT own the CoroData object! That's owned
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// by LLCoros::mCoros. It merely identifies it. For this reason we
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// instantiate it with a no-op cleanup function.
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static boost::thread_specific_ptr<LLCoros::CoroData> sCurrent(LLCoros::no_cleanup);
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// If this is the first time we're accessing sCurrent for the running
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// thread, its get() will be NULL. This could be a problem, in that
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// llcoro::get_id() would return the same (NULL) token value for the "main
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// coroutine" in every thread, whereas what we really want is a distinct
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// value for every distinct stack in the process. So if get() is NULL,
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// give it a heap CoroData: this ensures that llcoro::get_id() will return
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// distinct values.
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// This tactic is "leaky": sCurrent explicitly does not destroy any
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// CoroData to which it points, and we do NOT enter these "main coroutine"
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// CoroData instances in the LLCoros::mCoros map. They are dummy entries,
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// and they will leak at process shutdown: one CoroData per thread.
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if (! sCurrent.get())
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{
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// It's tempting to provide a distinct name for each thread's "main
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// coroutine." But as getName() has always returned the empty string
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// to mean "not in a coroutine," empty string should suffice here --
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// and truthfully the additional (thread-safe!) machinery to ensure
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// uniqueness just doesn't feel worth the trouble.
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// We use a no-op callable and a minimal stack size because, although
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// CoroData's constructor in fact initializes its mCoro with a
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// coroutine with that stack size, no one ever actually enters it by
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// calling mCoro().
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sCurrent.reset(new CoroData(0, // no prev
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"", // not a named coroutine
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no_op, // no-op callable
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1024)); // stacksize moot
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}
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mCurrent = &sCurrent;
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}
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//static
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LLCoros::CoroData& LLCoros::get_CoroData(const std::string& caller)
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{
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CoroData* current = Current();
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// With the dummy CoroData set in LLCoros::Current::Current(), this
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// pointer should never be NULL.
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llassert_always(current);
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return *current;
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}
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//static
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LLCoros::coro::self& LLCoros::get_self()
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{
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CoroData& current = get_CoroData("get_self()");
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if (! current.mSelf)
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{
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LL_ERRS("LLCoros") << "Calling get_self() from non-coroutine context!" << LL_ENDL;
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}
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return *current.mSelf;
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}
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//static
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void LLCoros::set_consuming(bool consuming)
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{
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get_CoroData("set_consuming()").mConsuming = consuming;
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}
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//static
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bool LLCoros::get_consuming()
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{
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return get_CoroData("get_consuming()").mConsuming;
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}
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llcoro::Suspending::Suspending()
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{
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LLCoros::Current current;
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// Remember currently-running coroutine: we're about to suspend it.
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mSuspended = current;
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// Revert Current to the value it had at the moment we last switched
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// into this coroutine.
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current.reset(mSuspended->mPrev);
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}
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llcoro::Suspending::~Suspending()
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{
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LLCoros::Current current;
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// Okay, we're back, update our mPrev
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mSuspended->mPrev = current;
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// and reinstate our Current.
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current.reset(mSuspended);
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}
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LLCoros::LLCoros():
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// MAINT-2724: default coroutine stack size too small on Windows.
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// Previously we used
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// boost::context::guarded_stack_allocator::default_stacksize();
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// empirically this is 64KB on Windows and Linux. Try quadrupling.
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#if ADDRESS_SIZE == 64
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mStackSize(512*1024)
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#else
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mStackSize(256*1024)
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#endif
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{
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// Register our cleanup() method for "mainloop" ticks
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LLEventPumps::instance().obtain("mainloop").listen(
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"LLCoros", boost::bind(&LLCoros::cleanup, this, _1));
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}
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bool LLCoros::cleanup(const LLSD&)
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{
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static std::string previousName;
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static int previousCount = 0;
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// Walk the mCoros map, checking and removing completed coroutines.
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for (CoroMap::iterator mi(mCoros.begin()), mend(mCoros.end()); mi != mend; )
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{
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// Has this coroutine exited (normal return, exception, exit() call)
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// since last tick?
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if (mi->second->mCoro.exited())
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{
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if (previousName != mi->first)
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{
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previousName = mi->first;
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previousCount = 1;
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}
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else
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{
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++previousCount;
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}
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if ((previousCount < 5) || !(previousCount % 50))
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{
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if (previousCount < 5)
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LL_DEBUGS("LLCoros") << "LLCoros: cleaning up coroutine " << mi->first << LL_ENDL;
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else
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LL_DEBUGS("LLCoros") << "LLCoros: cleaning up coroutine " << mi->first << "("<< previousCount << ")" << LL_ENDL;
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}
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// The erase() call will invalidate its passed iterator value --
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// so increment mi FIRST -- but pass its original value to
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// erase(). This is what postincrement is all about.
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mCoros.erase(mi++);
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}
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else
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{
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// Still live, just skip this entry as if incrementing at the top
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// of the loop as usual.
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++mi;
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}
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}
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return false;
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}
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std::string LLCoros::generateDistinctName(const std::string& prefix) const
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{
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static std::string previousName;
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static int previousCount = 0;
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// Allowing empty name would make getName()'s not-found return ambiguous.
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if (prefix.empty())
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{
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LL_ERRS("LLCoros") << "LLCoros::launch(): pass non-empty name string" << LL_ENDL;
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}
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// If the specified name isn't already in the map, just use that.
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std::string name(prefix);
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// Find the lowest numeric suffix that doesn't collide with an existing
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// entry. Start with 2 just to make it more intuitive for any interested
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// parties: e.g. "joe", "joe2", "joe3"...
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for (int i = 2; ; name = STRINGIZE(prefix << i++))
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{
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if (mCoros.find(name) == mCoros.end())
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{
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if (previousName != name)
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{
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previousName = name;
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previousCount = 1;
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}
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else
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{
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++previousCount;
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}
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if ((previousCount < 5) || !(previousCount % 50))
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{
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if (previousCount < 5)
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LL_DEBUGS("LLCoros") << "LLCoros: launching coroutine " << name << LL_ENDL;
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else
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LL_DEBUGS("LLCoros") << "LLCoros: launching coroutine " << name << "(" << previousCount << ")" << LL_ENDL;
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}
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return name;
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}
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}
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}
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bool LLCoros::kill(const std::string& name)
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{
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CoroMap::iterator found = mCoros.find(name);
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if (found == mCoros.end())
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{
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return false;
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}
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// Because this is a boost::ptr_map, erasing the map entry also destroys
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// the referenced heap object, in this case the boost::coroutine object,
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// which will terminate the coroutine.
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mCoros.erase(found);
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return true;
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}
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std::string LLCoros::getName() const
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{
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return Current()->mName;
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}
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void LLCoros::setStackSize(S32 stacksize)
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{
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LL_DEBUGS("LLCoros") << "Setting coroutine stack size to " << stacksize << LL_ENDL;
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mStackSize = stacksize;
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}
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#if LL_WINDOWS
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static const U32 STATUS_MSC_EXCEPTION = 0xE06D7363; // compiler specific
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U32 exception_filter(U32 code, struct _EXCEPTION_POINTERS *exception_infop)
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{
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if (code == STATUS_MSC_EXCEPTION)
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{
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// C++ exception, go on
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return EXCEPTION_CONTINUE_SEARCH;
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}
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else
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{
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// handle it
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return EXCEPTION_EXECUTE_HANDLER;
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}
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}
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void LLCoros::winlevel(const callable_t& callable)
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{
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__try
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{
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callable();
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}
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__except (exception_filter(GetExceptionCode(), GetExceptionInformation()))
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{
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// convert to C++ styled exception
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// Note: it might be better to use _se_set_translator
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// if you want exception to inherit full callstack
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char integer_string[32];
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sprintf(integer_string, "SEH, code: %lu\n", GetExceptionCode());
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throw std::exception(integer_string);
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}
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}
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#endif
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// Top-level wrapper around caller's coroutine callable. This function accepts
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// the coroutine library's implicit coro::self& parameter and saves it, but
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// does not pass it down to the caller's callable.
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void LLCoros::toplevel(coro::self& self, CoroData* data, const callable_t& callable)
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{
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// capture the 'self' param in CoroData
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data->mSelf = &self;
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// run the code the caller actually wants in the coroutine
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try
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{
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#if LL_WINDOWS
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winlevel(callable);
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#else
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callable();
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#endif
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}
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catch (const LLContinueError&)
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{
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// Any uncaught exception derived from LLContinueError will be caught
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// here and logged. This coroutine will terminate but the rest of the
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// viewer will carry on.
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LOG_UNHANDLED_EXCEPTION(STRINGIZE("coroutine " << data->mName));
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}
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catch (...)
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{
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// Any OTHER kind of uncaught exception will cause the viewer to
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// crash, hopefully informatively.
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CRASH_ON_UNHANDLED_EXCEPTION(STRINGIZE("coroutine " << data->mName));
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}
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// This cleanup isn't perfectly symmetrical with the way we initially set
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// data->mPrev, but this is our last chance to reset Current.
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Current().reset(data->mPrev);
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}
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/*****************************************************************************
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* MUST BE LAST
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*****************************************************************************/
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// Turn off MSVC optimizations for just LLCoros::launch() -- see
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// DEV-32777. But MSVC doesn't support push/pop for optimization flags as it
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// does for warning suppression, and we really don't want to force
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// optimization ON for other code even in Debug or RelWithDebInfo builds.
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#if LL_MSVC
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// work around broken optimizations
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#pragma warning(disable: 4748)
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#pragma warning(disable: 4355) // 'this' used in initializer list: yes, intentionally
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#pragma optimize("", off)
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#endif // LL_MSVC
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LLCoros::CoroData::CoroData(CoroData* prev, const std::string& name,
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const callable_t& callable, S32 stacksize):
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mPrev(prev),
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mName(name),
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// Wrap the caller's callable in our toplevel() function so we can manage
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// Current appropriately at startup and shutdown of each coroutine.
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mCoro(boost::bind(toplevel, _1, this, callable), stacksize),
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// don't consume events unless specifically directed
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mConsuming(false),
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mSelf(0)
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{
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}
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std::string LLCoros::launch(const std::string& prefix, const callable_t& callable)
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{
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std::string name(generateDistinctName(prefix));
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Current current;
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// pass the current value of Current as previous context
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CoroData* newCoro = new CoroData(current, name, callable, mStackSize);
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// Store it in our pointer map
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mCoros.insert(name, newCoro);
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// also set it as current
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current.reset(newCoro);
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/* Run the coroutine until its first wait, then return here */
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(newCoro->mCoro)(std::nothrow);
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return name;
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}
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#if LL_MSVC
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// reenable optimizations
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#pragma optimize("", on)
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#endif // LL_MSVC
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