Fix cUrlClient leak (#4125)

Fixes #4040
* The TCP connection is now shutdown after OnBodyFinished
* Any open connections are closed when cNetworkSingleton::Terminate() is called.
* Removed ownership cycles in cUrlClientRequest
* Added a check to the test to ensure there are no leaks.

src/OSSupport/NetworkSingleton.cpp

@@ -6,6 +6,7 @@
 
 #include "Globals.h"
 #include "NetworkSingleton.h"
+#include "OSSupport/Network.h"
 #include <event2/thread.h>
 #include <event2/bufferevent.h>
 #include <event2/listener.h>
@@ -102,11 +103,25 @@ void cNetworkSingleton::Terminate(void)
 	event_base_loopbreak(m_EventBase);
 	m_EventLoopThread.join();
 
-	// Remove all objects:
+	// Close all open connections:
 	{
 		cCSLock Lock(m_CS);
-		m_Connections.clear();
-		m_Servers.clear();
+		// Must take copies because Close will modify lists
+		auto Conns = m_Connections;
+		for (auto & Conn : Conns)
+		{
+			Conn->Close();
+		}
+
+		auto Servers = m_Servers;
+		for (auto & Server : Servers)
+		{
+			Server->Close();
+		}
+
+		// Closed handles should have removed themself
+		ASSERT(m_Connections.empty());
+		ASSERT(m_Servers.empty());
 	}
 
 	// Free the underlying LibEvent objects:
@@ -167,7 +182,7 @@ void cNetworkSingleton::SignalizeStartup(evutil_socket_t a_Socket, short a_Event
 
 
 
-void cNetworkSingleton::AddLink(cTCPLinkImplPtr a_Link)
+void cNetworkSingleton::AddLink(cTCPLinkPtr a_Link)
 {
 	ASSERT(!m_HasTerminated);
 	cCSLock Lock(m_CS);
@@ -178,7 +193,7 @@ void cNetworkSingleton::AddLink(cTCPLinkImplPtr a_Link)
 
 
 
-void cNetworkSingleton::RemoveLink(const cTCPLinkImpl * a_Link)
+void cNetworkSingleton::RemoveLink(const cTCPLink * a_Link)
 {
 	ASSERT(!m_HasTerminated);
 	cCSLock Lock(m_CS);
@@ -196,7 +211,7 @@ void cNetworkSingleton::RemoveLink(const cTCPLinkImpl * a_Link)
 
 
 
-void cNetworkSingleton::AddServer(cServerHandleImplPtr a_Server)
+void cNetworkSingleton::AddServer(cServerHandlePtr a_Server)
 {
 	ASSERT(!m_HasTerminated);
 	cCSLock Lock(m_CS);
@@ -207,7 +222,7 @@ void cNetworkSingleton::AddServer(cServerHandleImplPtr a_Server)
 
 
 
-void cNetworkSingleton::RemoveServer(const cServerHandleImpl * a_Server)
+void cNetworkSingleton::RemoveServer(const cServerHandle * a_Server)
 {
 	ASSERT(!m_HasTerminated);
 	cCSLock Lock(m_CS);

src/OSSupport/NetworkSingleton.h

@@ -24,12 +24,12 @@
 
 // fwd:
 struct event_base;
-class cTCPLinkImpl;
-typedef std::shared_ptr<cTCPLinkImpl> cTCPLinkImplPtr;
-typedef std::vector<cTCPLinkImplPtr> cTCPLinkImplPtrs;
-class cServerHandleImpl;
-typedef std::shared_ptr<cServerHandleImpl> cServerHandleImplPtr;
-typedef std::vector<cServerHandleImplPtr> cServerHandleImplPtrs;
+class cTCPLink;
+typedef std::shared_ptr<cTCPLink> cTCPLinkPtr;
+typedef std::vector<cTCPLinkPtr> cTCPLinkPtrs;
+class cServerHandle;
+typedef std::shared_ptr<cServerHandle> cServerHandlePtr;
+typedef std::vector<cServerHandlePtr> cServerHandlePtrs;
 
 
 
@@ -61,20 +61,20 @@ public:
 
 	/** Adds the specified link to m_Connections.
 	Used by the underlying link implementation when a new link is created. */
-	void AddLink(cTCPLinkImplPtr a_Link);
+	void AddLink(cTCPLinkPtr a_Link);
 
 	/** Removes the specified link from m_Connections.
 	Used by the underlying link implementation when the link is closed / errored. */
-	void RemoveLink(const cTCPLinkImpl * a_Link);
+	void RemoveLink(const cTCPLink * a_Link);
 
 	/** Adds the specified link to m_Servers.
 	Used by the underlying server handle implementation when a new listening server is created.
 	Only servers that succeed in listening are added. */
-	void AddServer(cServerHandleImplPtr a_Server);
+	void AddServer(cServerHandlePtr a_Server);
 
 	/** Removes the specified server from m_Servers.
 	Used by the underlying server handle implementation when the server is closed. */
-	void RemoveServer(const cServerHandleImpl * a_Server);
+	void RemoveServer(const cServerHandle * a_Server);
 
 protected:
 
@@ -82,10 +82,10 @@ protected:
 	event_base * m_EventBase;
 
 	/** Container for all client connections, including ones with pending-connect. */
-	cTCPLinkImplPtrs m_Connections;
+	cTCPLinkPtrs m_Connections;
 
 	/** Container for all servers that are currently active. */
-	cServerHandleImplPtrs m_Servers;
+	cServerHandlePtrs m_Servers;
 
 	/** Mutex protecting all containers against multithreaded access. */
 	cCriticalSection m_CS;