Major plugin refactor and cleanup.

Switched to POCO library for unified platform/library interface.
Deprecated the external module API. It was creating more problems than solving.
Removed most built-in libraries in favor of system libraries for easier maintenance.
Cleaned and secured code with help from static analyzers.

vendor/POCO/Foundation/include/Poco/LRUStrategy.h

@@ -0,0 +1,140 @@
+//
+// LRUStrategy.h
+//
+// Library: Foundation
+// Package: Cache
+// Module:  LRUStrategy
+//
+// Definition of the LRUStrategy class.
+//
+// Copyright (c) 2006, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// SPDX-License-Identifier:	BSL-1.0
+//
+
+
+#ifndef Foundation_LRUStrategy_INCLUDED
+#define Foundation_LRUStrategy_INCLUDED
+
+
+#include "Poco/KeyValueArgs.h"
+#include "Poco/ValidArgs.h"
+#include "Poco/AbstractStrategy.h"
+#include "Poco/EventArgs.h"
+#include "Poco/Exception.h"
+#include <list>
+#include <map>
+#include <cstddef>
+
+
+namespace Poco {
+
+
+template <class TKey, class TValue>
+class LRUStrategy: public AbstractStrategy<TKey, TValue>
+	/// An LRUStrategy implements least recently used cache replacement.
+{
+public:
+	typedef std::list<TKey>                   Keys;
+	typedef typename Keys::iterator           Iterator;
+	typedef typename Keys::const_iterator     ConstIterator;
+	typedef std::map<TKey, Iterator>          KeyIndex;
+	typedef typename KeyIndex::iterator       IndexIterator;
+	typedef typename KeyIndex::const_iterator ConstIndexIterator;
+
+public:
+	LRUStrategy(std::size_t size): 
+		_size(size)
+	{
+		if (_size < 1) throw InvalidArgumentException("size must be > 0");
+	}
+
+	~LRUStrategy()
+	{
+	}
+
+	void onAdd(const void*, const KeyValueArgs <TKey, TValue>& args)
+	{
+		_keys.push_front(args.key());
+		std::pair<IndexIterator, bool> stat = _keyIndex.insert(std::make_pair(args.key(), _keys.begin()));
+		if (!stat.second)
+		{
+			stat.first->second = _keys.begin();
+		}
+	}
+
+	void onRemove(const void*, const TKey& key)
+	{
+		IndexIterator it = _keyIndex.find(key);
+
+		if (it != _keyIndex.end())
+		{
+			_keys.erase(it->second);
+			_keyIndex.erase(it);
+		}
+	}
+
+	void onGet(const void*, const TKey& key)
+	{
+		// LRU: in case of an hit, move to begin
+		IndexIterator it = _keyIndex.find(key);
+
+		if (it != _keyIndex.end())
+		{
+			_keys.splice(_keys.begin(), _keys, it->second); //_keys.erase(it->second)+_keys.push_front(key);
+			it->second = _keys.begin();
+		}
+	}
+
+	void onClear(const void*, const EventArgs& args)
+	{
+		_keys.clear();
+		_keyIndex.clear();
+	}
+
+	void onIsValid(const void*, ValidArgs<TKey>& args)
+	{
+		if (_keyIndex.find(args.key()) == _keyIndex.end())
+		{
+			args.invalidate();
+		}
+	}
+
+	void onReplace(const void*, std::set<TKey>& elemsToRemove)
+	{
+		// Note: replace only informs the cache which elements
+		// it would like to remove!
+		// it does not remove them on its own!
+		std::size_t curSize = _keyIndex.size();
+
+		if (curSize < _size)
+		{
+			return;
+		}
+
+		std::size_t diff = curSize - _size;
+		Iterator it = --_keys.end(); //--keys can never be invoked on an empty list due to the minSize==1 requirement of LRU
+		std::size_t i = 0;
+
+		while (i++ < diff) 
+		{
+			elemsToRemove.insert(*it);
+			if (it != _keys.begin())
+			{
+				--it;
+			}
+		}
+	}
+
+protected:
+	std::size_t _size;     /// Number of keys the cache can store.
+	Keys        _keys;
+	KeyIndex    _keyIndex; /// For faster access to _keys
+};
+
+
+} // namespace Poco
+
+
+#endif // Foundation_LRUStrategy_INCLUDED