thread safe getFieldCreate() and getPVDataCreate()

Fully thread safe and ctor order safe on all targets
(not just c++11).  Never destroyed to avoid global
dtor order issues.

src/factory/FieldCreateFactory.cpp

@@ -19,6 +19,7 @@
 #include <sstream>
 
 #include <epicsMutex.h>
+#include <epicsThread.h>
 
 #define epicsExportSharedSymbols
 #include <pv/reftrack.h>
@@ -1452,18 +1453,33 @@ FieldConstPtr FieldCreate::deserialize(ByteBuffer* buffer, DeserializableControl
     }
 }
 
-// TODO replace with non-locking singleton pattern
-const FieldCreatePtr& FieldCreate::getFieldCreate()
-{
-	static FieldCreatePtr fieldCreate;
-	static Mutex mutex;
-
-	Lock xx(mutex);
-    if(fieldCreate.get()==0) {
-        fieldCreate = FieldCreatePtr(new FieldCreate());
+namespace detail {
+struct field_factory {
+    FieldCreatePtr fieldCreate;
+    field_factory() :fieldCreate(new FieldCreate()) {
         registerRefCounter("Field", &Field::num_instances);
     }
-    return fieldCreate;
+};
+}
+
+static detail::field_factory* field_factory_s;
+static epicsThreadOnceId field_factory_once = EPICS_THREAD_ONCE_INIT;
+
+static void field_factory_init(void*)
+{
+    try {
+        field_factory_s = new detail::field_factory;
+    }catch(std::exception& e){
+        std::cerr<<"Error initializing getFieldCreate() : "<<e.what()<<"\n";
+    }
+}
+
+const FieldCreatePtr& FieldCreate::getFieldCreate()
+{
+    epicsThreadOnce(&field_factory_once, &field_factory_init, 0);
+    if(!field_factory_s->fieldCreate)
+        throw std::logic_error("getFieldCreate() not initialized");
+    return field_factory_s->fieldCreate;
 }
 
 FieldCreate::FieldCreate()

src/factory/PVDataCreateFactory.cpp

@@ -17,6 +17,7 @@
 #include <cstdio>
 
 #include <epicsMutex.h>
+#include <epicsThread.h>
 
 #define epicsExportSharedSymbols
 #include <pv/lock.h>
@@ -604,19 +605,33 @@ PVUnionPtr PVDataCreate::createPVUnion(PVUnionPtr const & unionToClone)
     return punion;
 }
 
-// TODO not thread-safe (local static initializers)
-// TODO replace with non-locking singleton pattern
+namespace detail {
+struct pvfield_factory {
+    PVDataCreatePtr pvDataCreate;
+    pvfield_factory() :pvDataCreate(new PVDataCreate()) {
+        registerRefCounter("PVField", &PVField::num_instances);
+    }
+};
+}
+
+static detail::pvfield_factory* pvfield_factory_s;
+static epicsThreadOnceId pvfield_factory_once = EPICS_THREAD_ONCE_INIT;
+
+static void pvfield_factory_init(void*)
+{
+    try {
+        pvfield_factory_s = new detail::pvfield_factory;
+    }catch(std::exception& e){
+        std::cerr<<"Error initializing getFieldCreate() : "<<e.what()<<"\n";
+    }
+}
+
 const PVDataCreatePtr& PVDataCreate::getPVDataCreate()
 {
-    static PVDataCreatePtr pvDataCreate;
-    static Mutex mutex;
-    Lock xx(mutex);
-
-    if(pvDataCreate.get()==0) {
-        registerRefCounter("PVField", &PVField::num_instances);
-        pvDataCreate = PVDataCreatePtr(new PVDataCreate());
-    }
-    return pvDataCreate;
+    epicsThreadOnce(&pvfield_factory_once, &pvfield_factory_init, 0);
+    if(!pvfield_factory_s->pvDataCreate)
+        throw std::logic_error("getPVDataCreate() not initialized");
+    return pvfield_factory_s->pvDataCreate;
 }
 
 // explicitly instanciate to ensure that windows

src/pv/pvData.h

@@ -1475,11 +1475,16 @@ typedef std::tr1::shared_ptr<PVDoubleArray> PVDoubleArrayPtr;
 typedef PVValueArray<std::string> PVStringArray;
 typedef std::tr1::shared_ptr<PVStringArray> PVStringArrayPtr;
 
+namespace detail {
+struct pvfield_factory;
+}
+
 /**
  * @brief This is a singleton class for creating data instances.
  *
  */
 class epicsShareClass PVDataCreate {
+    friend struct detail::pvfield_factory;
 public:
     /**
      * get the singleton

src/pv/pvIntrospect.h

@@ -1065,11 +1065,16 @@ private:
     const bool createNested; // true - endNested() creates in parent, false - endNested() appends to parent
 };
 
+namespace detail {
+struct field_factory;
+}
+
 /**
  * @brief This is a singleton class for creating introspection interfaces.
  *
  */
 class epicsShareClass FieldCreate {
+    friend struct detail::field_factory;
 public:
     static const FieldCreatePtr &getFieldCreate();
 	/**