merge changes for 5.0.1-release

1 files changed, 439 insertions, 1 deletions

diff --git a/indra/llcommon/llsingleton.cpp b/indra/llcommon/llsingleton.cpp
index 9b49e52377..9025e53bb2 100644
--- a/indra/llcommon/llsingleton.cpp
+++ b/indra/llcommon/llsingleton.cpp
@@ -25,7 +25,445 @@
  */
 
 #include "linden_common.h"
-
 #include "llsingleton.h"
 
+#include "llerror.h"
+#include "llerrorcontrol.h"         // LLError::is_available()
+#include "lldependencies.h"
+#include "llcoro_get_id.h"
+#include <boost/foreach.hpp>
+#include <boost/unordered_map.hpp>
+#include <algorithm>
+#include <iostream>                 // std::cerr in dire emergency
+#include <sstream>
+#include <stdexcept>
+
+namespace {
+void log(LLError::ELevel level,
+         const char* p1, const char* p2, const char* p3, const char* p4);
+
+void logdebugs(const char* p1="", const char* p2="", const char* p3="", const char* p4="");
+
+bool oktolog();
+} // anonymous namespace
+
+// Our master list of all LLSingletons is itself an LLSingleton. We used to
+// store it in a function-local static, but that could get destroyed before
+// the last of the LLSingletons -- and ~LLSingletonBase() definitely wants to
+// remove itself from the master list. Since the whole point of this master
+// list is to help track inter-LLSingleton dependencies, and since we have
+// this implicit dependency from every LLSingleton to the master list, make it
+// an LLSingleton.
+class LLSingletonBase::MasterList:
+    public LLSingleton<LLSingletonBase::MasterList>
+{
+    LLSINGLETON_EMPTY_CTOR(MasterList);
+
+public:
+    // No need to make this private with accessors; nobody outside this source
+    // file can see it.
+
+    // This is the master list of all instantiated LLSingletons (save the
+    // MasterList itself) in arbitrary order. You MUST call dep_sort() before
+    // traversing this list.
+    LLSingletonBase::list_t mMaster;
+
+    // We need to maintain a stack of LLSingletons currently being
+    // initialized, either in the constructor or in initSingleton(). However,
+    // managing that as a stack depends on having a DISTINCT 'initializing'
+    // stack for every C++ stack in the process! And we have a distinct C++
+    // stack for every running coroutine. It would be interesting and cool to
+    // implement a generic coroutine-local-storage mechanism and use that
+    // here. The trouble is that LLCoros is itself an LLSingleton, so
+    // depending on LLCoros functionality could dig us into infinite
+    // recursion. (Moreover, when we reimplement LLCoros on top of
+    // Boost.Fiber, that library already provides fiber_specific_ptr -- so
+    // it's not worth a great deal of time and energy implementing a generic
+    // equivalent on top of boost::dcoroutine, which is on its way out.)
+    // Instead, use a map of llcoro::id to select the appropriate
+    // coro-specific 'initializing' stack. llcoro::get_id() is carefully
+    // implemented to avoid requiring LLCoros.
+    typedef boost::unordered_map<llcoro::id, LLSingletonBase::list_t> InitializingMap;
+    InitializingMap mInitializing;
+
+    // non-static method, cf. LLSingletonBase::get_initializing()
+    list_t& get_initializing_()
+    {
+        // map::operator[] has find-or-create semantics, exactly what we need
+        // here. It returns a reference to the selected mapped_type instance.
+        return mInitializing[llcoro::get_id()];
+    }
+
+    void cleanup_initializing_()
+    {
+        InitializingMap::iterator found = mInitializing.find(llcoro::get_id());
+        if (found != mInitializing.end())
+        {
+            mInitializing.erase(found);
+        }
+    }
+};
+
+//static
+LLSingletonBase::list_t& LLSingletonBase::get_master()
+{
+    return LLSingletonBase::MasterList::instance().mMaster;
+}
+
+void LLSingletonBase::add_master()
+{
+    // As each new LLSingleton is constructed, add to the master list.
+    get_master().push_back(this);
+}
+
+void LLSingletonBase::remove_master()
+{
+    // When an LLSingleton is destroyed, remove from master list.
+    // add_master() used to capture the iterator to the newly-added list item
+    // so we could directly erase() it from the master list. Unfortunately
+    // that runs afoul of destruction-dependency order problems. So search the
+    // master list, and remove this item IF FOUND. We have few enough
+    // LLSingletons, and they are so rarely destroyed (once per run), that the
+    // cost of a linear search should not be an issue.
+    get_master().remove(this);
+}
+
+//static
+LLSingletonBase::list_t& LLSingletonBase::get_initializing()
+{
+    return LLSingletonBase::MasterList::instance().get_initializing_();
+}
+
+//static
+LLSingletonBase::list_t& LLSingletonBase::get_initializing_from(MasterList* master)
+{
+    return master->get_initializing_();
+}
+
+LLSingletonBase::~LLSingletonBase() {}
+
+void LLSingletonBase::push_initializing(const char* name)
+{
+    // log BEFORE pushing so logging singletons don't cry circularity
+    log_initializing("Pushing", name);
+    get_initializing().push_back(this);
+}
+
+void LLSingletonBase::pop_initializing()
+{
+    list_t& list(get_initializing());
+
+    if (list.empty())
+    {
+        logerrs("Underflow in stack of currently-initializing LLSingletons at ",
+                demangle(typeid(*this).name()).c_str(), "::getInstance()");
+    }
+
+    // Now we know list.back() exists: capture it
+    LLSingletonBase* back(list.back());
+    // and pop it
+    list.pop_back();
+
+    // The viewer launches an open-ended number of coroutines. While we don't
+    // expect most of them to initialize LLSingleton instances, our present
+    // get_initializing() logic could lead to an open-ended number of map
+    // entries. So every time we pop the stack back to empty, delete the entry
+    // entirely.
+    if (list.empty())
+    {
+        MasterList::instance().cleanup_initializing_();
+    }
+
+    // Now validate the newly-popped LLSingleton.
+    if (back != this)
+    {
+        logerrs("Push/pop mismatch in stack of currently-initializing LLSingletons: ",
+                demangle(typeid(*this).name()).c_str(), "::getInstance() trying to pop ",
+                demangle(typeid(*back).name()).c_str());
+    }
+
+    // log AFTER popping so logging singletons don't cry circularity
+    log_initializing("Popping", typeid(*back).name());
+}
+
+//static
+void LLSingletonBase::log_initializing(const char* verb, const char* name)
+{
+    if (oktolog())
+    {
+        LL_DEBUGS("LLSingleton") << verb << ' ' << demangle(name) << ';';
+        list_t& list(get_initializing());
+        for (list_t::const_reverse_iterator ri(list.rbegin()), rend(list.rend());
+             ri != rend; ++ri)
+        {
+            LLSingletonBase* sb(*ri);
+            LL_CONT << ' ' << demangle(typeid(*sb).name());
+        }
+        LL_ENDL;
+    }
+}
+
+void LLSingletonBase::capture_dependency(list_t& initializing, EInitState initState)
+{
+    // Did this getInstance() call come from another LLSingleton, or from
+    // vanilla application code? Note that although this is a nontrivial
+    // method, the vast majority of its calls arrive here with initializing
+    // empty().
+    if (! initializing.empty())
+    {
+        // getInstance() is being called by some other LLSingleton. But -- is
+        // this a circularity? That is, does 'this' already appear in the
+        // initializing stack?
+        // For what it's worth, normally 'initializing' should contain very
+        // few elements.
+        list_t::const_iterator found =
+            std::find(initializing.begin(), initializing.end(), this);
+        if (found != initializing.end())
+        {
+            // Report the circularity. Requiring the coder to dig through the
+            // logic to diagnose exactly how we got here is less than helpful.
+            std::ostringstream out;
+            for ( ; found != initializing.end(); ++found)
+            {
+                // 'found' is an iterator; *found is an LLSingletonBase*; **found
+                // is the actual LLSingletonBase instance.
+                LLSingletonBase* foundp(*found);
+                out << demangle(typeid(*foundp).name()) << " -> ";
+            }
+            // We promise to capture dependencies from both the constructor
+            // and the initSingleton() method, so an LLSingleton's instance
+            // pointer is on the initializing list during both. Now that we've
+            // detected circularity, though, we must distinguish the two. If
+            // the recursive call is from the constructor, we CAN'T honor it:
+            // otherwise we'd be returning a pointer to a partially-
+            // constructed object! But from initSingleton() is okay: that
+            // method exists specifically to support circularity.
+            // Decide which log helper to call based on initState. They have
+            // identical signatures.
+            ((initState == CONSTRUCTING)? logerrs : logwarns)
+                ("LLSingleton circularity: ", out.str().c_str(),
+                 demangle(typeid(*this).name()).c_str(), "");
+        }
+        else
+        {
+            // Here 'this' is NOT already in the 'initializing' stack. Great!
+            // Record the dependency.
+            // initializing.back() is the LLSingletonBase* currently being
+            // initialized. Store 'this' in its mDepends set.
+            LLSingletonBase* current(initializing.back());
+            if (current->mDepends.insert(this).second)
+            {
+                // only log the FIRST time we hit this dependency!
+                logdebugs(demangle(typeid(*current).name()).c_str(),
+                          " depends on ", demangle(typeid(*this).name()).c_str());
+            }
+        }
+    }
+}
+
+//static
+LLSingletonBase::vec_t LLSingletonBase::dep_sort()
+{
+    // While it would theoretically be possible to maintain a static
+    // SingletonDeps through the life of the program, dynamically adding and
+    // removing LLSingletons as they are created and destroyed, in practice
+    // it's less messy to construct it on demand. The overhead of doing so
+    // should happen basically twice: once for cleanupAll(), once for
+    // deleteAll().
+    typedef LLDependencies<LLSingletonBase*> SingletonDeps;
+    SingletonDeps sdeps;
+    list_t& master(get_master());
+    BOOST_FOREACH(LLSingletonBase* sp, master)
+    {
+        // Build the SingletonDeps structure by adding, for each
+        // LLSingletonBase* sp in the master list, sp itself. It has no
+        // associated value type in our SingletonDeps, hence the 0. We don't
+        // record the LLSingletons it must follow; rather, we record the ones
+        // it must precede. Copy its mDepends to a KeyList to express that.
+        sdeps.add(sp, 0,
+                  SingletonDeps::KeyList(),
+                  SingletonDeps::KeyList(sp->mDepends.begin(), sp->mDepends.end()));
+    }
+    vec_t ret;
+    ret.reserve(master.size());
+    // We should be able to effect this with a transform_iterator that
+    // extracts just the first (key) element from each sorted_iterator, then
+    // uses vec_t's range constructor... but frankly this is more
+    // straightforward, as long as we remember the above reserve() call!
+    BOOST_FOREACH(SingletonDeps::sorted_iterator::value_type pair, sdeps.sort())
+    {
+        ret.push_back(pair.first);
+    }
+    // The master list is not itself pushed onto the master list. Add it as
+    // the very last entry -- it is the LLSingleton on which ALL others
+    // depend! -- so our caller will process it.
+    ret.push_back(MasterList::getInstance());
+    return ret;
+}
+
+//static
+void LLSingletonBase::cleanupAll()
+{
+    // It's essential to traverse these in dependency order.
+    BOOST_FOREACH(LLSingletonBase* sp, dep_sort())
+    {
+        // Call cleanupSingleton() only if we haven't already done so for this
+        // instance.
+        if (! sp->mCleaned)
+        {
+            sp->mCleaned = true;
+
+            logdebugs("calling ",
+                      demangle(typeid(*sp).name()).c_str(), "::cleanupSingleton()");
+            try
+            {
+                sp->cleanupSingleton();
+            }
+            catch (const std::exception& e)
+            {
+                logwarns("Exception in ", demangle(typeid(*sp).name()).c_str(),
+                         "::cleanupSingleton(): ", e.what());
+            }
+            catch (...)
+            {
+                logwarns("Unknown exception in ", demangle(typeid(*sp).name()).c_str(),
+                         "::cleanupSingleton()");
+            }
+        }
+    }
+}
+
+//static
+void LLSingletonBase::deleteAll()
+{
+    // It's essential to traverse these in dependency order.
+    BOOST_FOREACH(LLSingletonBase* sp, dep_sort())
+    {
+        // Capture the class name first: in case of exception, don't count on
+        // being able to extract it later.
+        const std::string name = demangle(typeid(*sp).name());
+        try
+        {
+            // Call static method through instance function pointer.
+            if (! sp->mDeleteSingleton)
+            {
+                // This Should Not Happen... but carry on.
+                logwarns(name.c_str(), "::mDeleteSingleton not initialized!");
+            }
+            else
+            {
+                // properly initialized: call it.
+                logdebugs("calling ", name.c_str(), "::deleteSingleton()");
+                // From this point on, DO NOT DEREFERENCE sp!
+                sp->mDeleteSingleton();
+            }
+        }
+        catch (const std::exception& e)
+        {
+            logwarns("Exception in ", name.c_str(), "::deleteSingleton(): ", e.what());
+        }
+        catch (...)
+        {
+            logwarns("Unknown exception in ", name.c_str(), "::deleteSingleton()");
+        }
+    }
+}
+
+/*------------------------ Final cleanup management ------------------------*/
+class LLSingletonBase::MasterRefcount
+{
+public:
+    // store a POD int so it will be statically initialized to 0
+    int refcount;
+};
+static LLSingletonBase::MasterRefcount sMasterRefcount;
+
+LLSingletonBase::ref_ptr_t LLSingletonBase::get_master_refcount()
+{
+    // Calling this method constructs a new ref_ptr_t, which implicitly calls
+    // intrusive_ptr_add_ref(MasterRefcount*).
+    return &sMasterRefcount;
+}
+
+void intrusive_ptr_add_ref(LLSingletonBase::MasterRefcount* mrc)
+{
+    // Count outstanding SingletonLifetimeManager instances.
+    ++mrc->refcount;
+}
+
+void intrusive_ptr_release(LLSingletonBase::MasterRefcount* mrc)
+{
+    // Notice when each SingletonLifetimeManager instance is destroyed.
+    if (! --mrc->refcount)
+    {
+        // The last instance was destroyed. Time to kill any remaining
+        // LLSingletons -- but in dependency order.
+        LLSingletonBase::deleteAll();
+    }
+}
+
+/*---------------------------- Logging helpers -----------------------------*/
+namespace {
+bool oktolog()
+{
+    // See comments in log() below.
+    return sMasterRefcount.refcount && LLError::is_available();
+}
+
+void log(LLError::ELevel level,
+         const char* p1, const char* p2, const char* p3, const char* p4)
+{
+    // Check whether we're in the implicit final LLSingletonBase::deleteAll()
+    // call. We've carefully arranged for deleteAll() to be called when the
+    // last SingletonLifetimeManager instance is destroyed -- in other words,
+    // when the last translation unit containing an LLSingleton instance
+    // cleans up static data. That could happen after std::cerr is destroyed!
+    // The is_available() test below ensures that we'll stop logging once
+    // LLError has been cleaned up. If we had a similar portable test for
+    // std::cerr, this would be a good place to use it. As we do not, just
+    // don't log anything during implicit final deleteAll(). Detect that by
+    // the master refcount having gone to zero.
+    if (sMasterRefcount.refcount == 0)
+        return;
+
+    // Check LLError::is_available() because some of LLError's infrastructure
+    // is itself an LLSingleton. If that LLSingleton has not yet been
+    // initialized, trying to log will engage LLSingleton machinery... and
+    // around and around we go.
+    if (LLError::is_available())
+    {
+        LL_VLOGS(level, "LLSingleton") << p1 << p2 << p3 << p4 << LL_ENDL;
+    }
+    else
+    {
+        // Caller may be a test program, or something else whose stderr is
+        // visible to the user.
+        std::cerr << p1 << p2 << p3 << p4 << std::endl;
+    }
+}
+
+void logdebugs(const char* p1, const char* p2, const char* p3, const char* p4)
+{
+    log(LLError::LEVEL_DEBUG, p1, p2, p3, p4);
+}
+} // anonymous namespace        
+
+//static
+void LLSingletonBase::logwarns(const char* p1, const char* p2, const char* p3, const char* p4)
+{
+    log(LLError::LEVEL_WARN, p1, p2, p3, p4);
+}
+
+//static
+void LLSingletonBase::logerrs(const char* p1, const char* p2, const char* p3, const char* p4)
+{
+    log(LLError::LEVEL_ERROR, p1, p2, p3, p4);
+    // The other important side effect of LL_ERRS() is
+    // https://www.youtube.com/watch?v=OMG7paGJqhQ (emphasis on OMG)
+    LLError::crashAndLoop(std::string());
+}
 
+std::string LLSingletonBase::demangle(const char* mangled)
+{
+    return LLError::Log::demangle(mangled);
+}