added resource_api and rs-nogui-webui (requires libmicrohttpd, Html files are not included)

git-svn-id: http://svn.code.sf.net/p/retroshare/code/trunk@8047 b45a01b8-16f6-495d-af2f-9b41ad6348cc

libresapi/src/api/StateTokenServer.h

@@ -0,0 +1,69 @@
+#pragma once
+
+#include <util/rsthreads.h>
+#include "ResourceRouter.h"
+
+namespace resource_api
+{
+
+//class StreamBase;
+//class StateToken;
+
+// serialiser/deserialiser (depends on stream type)
+// for single value
+StreamBase& operator <<(StreamBase& left, KeyValueReference<StateToken> kv);
+// for lists
+StreamBase& operator <<(StreamBase& left, StateToken& token);
+bool operator ==(const StateToken& left, const StateToken& right);
+
+class Tickable{
+public:
+    virtual void tick() = 0;
+};
+
+
+class StateTokenServer: public ResourceRouter
+{
+public:
+    StateTokenServer();
+
+    // thread safe
+    // this allows tokens to be created and destroyed from arbitrary threads
+    StateToken getNewToken();
+    void discardToken(StateToken token);
+    // discard the token and fill in a new one
+    void replaceToken(StateToken& token);
+
+    void registerTickClient(Tickable* c);
+    void unregisterTickClient(Tickable* c);
+
+private:
+    void handleWildcard(Request& req, Response& resp);
+
+    StateToken locked_getNewToken();
+    void locked_discardToken(StateToken token);
+
+    RsMutex mMtx;
+
+    uint32_t mNextToken;
+    // not sure what the most efficient data structure for simple token storage is
+    // have to:
+    // - add elements
+    // - remove elements by value
+    // - store many values
+    // vector: expensive token erase, could make this better with a invalidate flag
+    // and periodic cleanup
+    // list: lots of overhead for pointers
+    // a set would offer cheap lookup
+    // we have to lookup often, so maybe this would be an option
+    // have to see where the bottleneck is in practice
+    // idea: invalidate all tokens after x minutes/hours, to limit the range of the token values
+    // then store the token states in a circular bitbuffer
+    std::vector<StateToken> mValidTokens;
+
+    // classes which want to be ticked
+    RsMutex mClientsMtx; // needs extra mutex, because clients may call back to modify get/delete tokens
+    std::vector<Tickable*> mTickClients;
+};
+
+} // namespace resource_api