STORM-1541: Hoist LLInstanceTracker::getMap_() to base getStatic().

Generalize the notion of getting some chunk of "static" storage: introduce
LLInstanceTrackerBase::getStatic() template method. Define StaticData struct
containing the InstanceMap (or InstanceSet, for that specialization) along
with the S32 that caused the VS2010 linker so much grief. Completely eliminate
that S32 as an actual class-static member, qualifying all references with the
struct returned by getStatic().
In LLInstanceTrackerBase::getInstances(), use one std::map lookup instead of
three.

1 files changed, 10 insertions, 9 deletions

diff --git a/indra/llcommon/llinstancetracker.cpp b/indra/llcommon/llinstancetracker.cpp
index f576204511..5dc3ea5d7b 100644
--- a/indra/llcommon/llinstancetracker.cpp
+++ b/indra/llcommon/llinstancetracker.cpp
@@ -35,14 +35,15 @@
 //static 
 void * & LLInstanceTrackerBase::getInstances(std::type_info const & info)
 {
-	static std::map<std::string, void *> instances;
+	typedef std::map<std::string, void *> InstancesMap;
+	static InstancesMap instances;
 
-	std::string k = info.name();
-	if(instances.find(k) == instances.end())
-	{
-		instances[k] = NULL;
-	}
-
-	return instances[k];
+	// std::map::insert() is just what we want here. You attempt to insert a
+	// (key, value) pair. If the specified key doesn't yet exist, it inserts
+	// the pair and returns a std::pair of (iterator, true). If the specified
+	// key DOES exist, insert() simply returns (iterator, false). One lookup
+	// handles both cases.
+	return instances.insert(InstancesMap::value_type(info.name(),
+													 InstancesMap::mapped_type()))
+		.first->second;
 }
-