make the JsonAdapter a proper singleton: private default c'tor. mutexed getInstance() method instead.

server/json-adapter.cc

@@ -13,8 +13,6 @@
 #include <functional>
 #include <tuple>
 
-#include <mutex>
-
 #include "json-adapter.hh"
 #include "daemonize.hh"
 #include "pEp-types.hh"
@@ -283,11 +281,6 @@ JsonAdapter::JsonAdapter()
 , i(new Internal{})
 , guard_1(Guard_1)
 {
-	if(!ja_singleton)
-	{
-		ja_singleton = this;
-	}
-	
 	i->eventBase.reset(event_base_new());
 	if (!i->eventBase)
 		throw std::runtime_error("Failed to create new base_event.");
@@ -586,6 +579,20 @@ void JsonAdapter::check_guard() const
 }
 
 
+std::recursive_mutex get_instance_mutex;
+
+JsonAdapter& JsonAdapter::getInstance()
+{
+	std::lock_guard<std::recursive_mutex> L(get_instance_mutex);
+	
+	if(!ja_singleton)
+	{
+		ja_singleton = new JsonAdapter();
+	}
+	
+	return *ja_singleton;
+}
+
 namespace {
 
 std::string to_string(const SessionRegistry& reg)

server/json-adapter.hh

@@ -12,8 +12,6 @@
 class JsonAdapter : public Context
 {
 public:
-	// creates an instance of the JSON adapter. It tries to bind the first available port in the given range
-	JsonAdapter();
 	
 	// calls shutdown() on the instance if it is still running().
 	virtual ~JsonAdapter();
@@ -98,7 +96,12 @@ public:
 	Internal* i; // pimpl for stable interface.
 	unsigned long long guard_1;
 
+	static JsonAdapter& getInstance();
+
 private:
+
+	// creates the one and only instance of the JSON adapter.
+	JsonAdapter();
 	static
 	void staticThreadFunc(JsonAdapter* that) { that->threadFunc(); }
 	

server/mini-adapter-main.cc

@@ -135,8 +135,7 @@ try
 		}
 	}
 
-	
-	JsonAdapter ja;
+	JsonAdapter& ja = JsonAdapter::getInstance();
 	ja.ignore_session_errors( ignore_missing_session)
 	  .deliver_html( !no_html )
 	  ;