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/Mutex.h

@@ -0,0 +1,391 @@
+//
+// Mutex.h
+//
+// Library: Foundation
+// Package: Threading
+// Module:  Mutex
+//
+// Definition of the Mutex and FastMutex classes.
+//
+// Copyright (c) 2004-2008, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// SPDX-License-Identifier:	BSL-1.0
+//
+
+
+#ifndef Foundation_Mutex_INCLUDED
+#define Foundation_Mutex_INCLUDED
+
+
+#include "Poco/Foundation.h"
+#include "Poco/Exception.h"
+#include "Poco/ScopedLock.h"
+#include "Poco/Timestamp.h"
+
+#if __cplusplus >= 201103L
+	#ifndef POCO_HAVE_STD_ATOMICS
+		#define POCO_HAVE_STD_ATOMICS
+	#endif
+#endif
+
+#ifdef POCO_HAVE_STD_ATOMICS
+	#include <atomic>
+#endif
+
+
+#if defined(POCO_OS_FAMILY_WINDOWS)
+#if defined(_WIN32_WCE)
+#include "Poco/Mutex_WINCE.h"
+#else
+#include "Poco/Mutex_WIN32.h"
+#endif
+#elif defined(POCO_VXWORKS)
+#include "Poco/Mutex_VX.h"
+#else
+#include "Poco/Mutex_POSIX.h"
+#endif
+
+
+namespace Poco {
+
+
+class Foundation_API Mutex: private MutexImpl
+	/// A Mutex (mutual exclusion) is a synchronization 
+	/// mechanism used to control access to a shared resource
+	/// in a concurrent (multithreaded) scenario.
+	/// Mutexes are recursive, that is, the same mutex can be 
+	/// locked multiple times by the same thread (but, of course,
+	/// not by other threads).
+	/// Using the ScopedLock class is the preferred way to automatically
+	/// lock and unlock a mutex.
+{
+public:
+	using ScopedLock = Poco::ScopedLock<Mutex>;
+	
+	Mutex();
+		/// creates the Mutex.
+		
+	~Mutex();
+		/// destroys the Mutex.
+
+	void lock();
+		/// Locks the mutex. Blocks if the mutex
+		/// is held by another thread.
+		
+	void lock(long milliseconds);
+		/// Locks the mutex. Blocks up to the given number of milliseconds
+		/// if the mutex is held by another thread. Throws a TimeoutException
+		/// if the mutex can not be locked within the given timeout.
+		///
+		/// Performance Note: On most platforms (including Windows), this member function is 
+		/// implemented using a loop calling (the equivalent of) tryLock() and Thread::sleep().
+		/// On POSIX platforms that support pthread_mutex_timedlock(), this is used.
+
+	bool tryLock();
+		/// Tries to lock the mutex. Returns false immediately
+		/// if the mutex is already held by another thread.
+		/// Returns true if the mutex was successfully locked.
+
+	bool tryLock(long milliseconds);
+		/// Locks the mutex. Blocks up to the given number of milliseconds
+		/// if the mutex is held by another thread.
+		/// Returns true if the mutex was successfully locked.
+		///
+		/// Performance Note: On most platforms (including Windows), this member function is 
+		/// implemented using a loop calling (the equivalent of) tryLock() and Thread::sleep().
+		/// On POSIX platforms that support pthread_mutex_timedlock(), this is used.
+
+	void unlock();
+		/// Unlocks the mutex so that it can be acquired by
+		/// other threads.
+	
+private:
+	Mutex(const Mutex&);
+	Mutex& operator = (const Mutex&);
+};
+
+
+class Foundation_API FastMutex: private FastMutexImpl
+	/// A FastMutex (mutual exclusion) is similar to a Mutex.
+	/// Unlike a Mutex, however, a FastMutex is not recursive,
+	/// which means that a deadlock will occur if the same
+	/// thread tries to lock a mutex it has already locked again.
+	/// Locking a FastMutex is faster than locking a recursive Mutex.
+	/// Using the ScopedLock class is the preferred way to automatically
+	/// lock and unlock a mutex.
+{
+public:
+	using ScopedLock = Poco::ScopedLock<FastMutex>;
+
+	FastMutex();
+		/// creates the Mutex.
+		
+	~FastMutex();
+		/// destroys the Mutex.
+
+	void lock();
+		/// Locks the mutex. Blocks if the mutex
+		/// is held by another thread.
+
+	void lock(long milliseconds);
+		/// Locks the mutex. Blocks up to the given number of milliseconds
+		/// if the mutex is held by another thread. Throws a TimeoutException
+		/// if the mutex can not be locked within the given timeout.
+		///
+		/// Performance Note: On most platforms (including Windows), this member function is 
+		/// implemented using a loop calling (the equivalent of) tryLock() and Thread::sleep().
+		/// On POSIX platforms that support pthread_mutex_timedlock(), this is used.
+
+	bool tryLock();
+		/// Tries to lock the mutex. Returns false immediately
+		/// if the mutex is already held by another thread.
+		/// Returns true if the mutex was successfully locked.
+
+	bool tryLock(long milliseconds);
+		/// Locks the mutex. Blocks up to the given number of milliseconds
+		/// if the mutex is held by another thread.
+		/// Returns true if the mutex was successfully locked.
+		///
+		/// Performance Note: On most platforms (including Windows), this member function is 
+		/// implemented using a loop calling (the equivalent of) tryLock() and Thread::sleep().
+		/// On POSIX platforms that support pthread_mutex_timedlock(), this is used.
+
+	void unlock();
+		/// Unlocks the mutex so that it can be acquired by
+		/// other threads.
+	
+private:
+	FastMutex(const FastMutex&);
+	FastMutex& operator = (const FastMutex&);
+};
+
+
+#ifdef POCO_HAVE_STD_ATOMICS
+
+class Foundation_API SpinlockMutex
+	/// A SpinlockMutex, implemented in terms of std::atomic_flag, as
+	/// busy-wait mutual exclusion.
+	///
+	/// While in some cases (eg. locking small blocks of code)
+	/// busy-waiting may be an optimal solution, in many scenarios
+	/// spinlock may not be the right choice - it is up to the user to
+	/// choose the proper mutex type for their particular case.
+	///
+	/// Works with the ScopedLock class.
+{
+public:
+	using ScopedLock = Poco::ScopedLock<SpinlockMutex>;
+
+	SpinlockMutex();
+		/// Creates the SpinlockMutex.
+
+	~SpinlockMutex();
+		/// Destroys the SpinlockMutex.
+
+	void lock();
+		/// Locks the mutex. Blocks if the mutex
+		/// is held by another thread.
+
+	void lock(long milliseconds);
+		/// Locks the mutex. Blocks up to the given number of milliseconds
+		/// if the mutex is held by another thread. Throws a TimeoutException
+		/// if the mutex can not be locked within the given timeout.
+
+	bool tryLock();
+		/// Tries to lock the mutex. Returns immediately, false
+		/// if the mutex is already held by another thread, true
+		/// if the mutex was successfully locked.
+
+	bool tryLock(long milliseconds);
+		/// Locks the mutex. Blocks up to the given number of milliseconds
+		/// if the mutex is held by another thread.
+		/// Returns true if the mutex was successfully locked.
+
+	void unlock();
+		/// Unlocks the mutex so that it can be acquired by
+		/// other threads.
+
+private:
+	std::atomic_flag _flag = ATOMIC_FLAG_INIT;
+};
+
+#endif // POCO_HAVE_STD_ATOMICS
+
+
+class Foundation_API NullMutex
+	/// A NullMutex is an empty mutex implementation
+	/// which performs no locking at all. Useful in policy driven design
+	/// where the type of mutex used can be now a template parameter allowing the user to switch
+	/// between thread-safe and not thread-safe depending on his need
+	/// Works with the ScopedLock class
+{
+public:
+	using ScopedLock = Poco::ScopedLock<NullMutex>;
+	
+	NullMutex()
+		/// Creates the NullMutex.
+	{
+	}
+		
+	~NullMutex()
+		/// Destroys the NullMutex.
+	{
+	}
+
+	void lock()
+		/// Does nothing.
+	{
+	}
+		
+	void lock(long)
+		/// Does nothing.
+	{
+	}
+
+	bool tryLock()
+		/// Does nothing and always returns true.
+	{
+		return true;
+	}
+
+	bool tryLock(long)
+		/// Does nothing and always returns true.
+	{
+		return true;
+	}
+
+	void unlock()
+		/// Does nothing.
+	{
+	}
+};
+
+
+//
+// inlines
+//
+
+//
+// Mutex
+//
+
+inline void Mutex::lock()
+{
+	lockImpl();
+}
+
+
+inline void Mutex::lock(long milliseconds)
+{
+	if (!tryLockImpl(milliseconds))
+		throw TimeoutException();
+}
+
+
+inline bool Mutex::tryLock()
+{
+	return tryLockImpl();
+}
+
+
+inline bool Mutex::tryLock(long milliseconds)
+{
+	return tryLockImpl(milliseconds);
+}
+
+
+inline void Mutex::unlock()
+{
+	unlockImpl();
+}
+
+
+//
+// FastMutex
+//
+
+inline void FastMutex::lock()
+{
+	lockImpl();
+}
+
+
+inline void FastMutex::lock(long milliseconds)
+{
+	if (!tryLockImpl(milliseconds))
+		throw TimeoutException();
+}
+
+
+inline bool FastMutex::tryLock()
+{
+	return tryLockImpl();
+}
+
+
+inline bool FastMutex::tryLock(long milliseconds)
+{
+	return tryLockImpl(milliseconds);
+}
+
+
+inline void FastMutex::unlock()
+{
+	unlockImpl();
+}
+
+
+#ifdef POCO_HAVE_STD_ATOMICS
+
+//
+// SpinlockMutex
+//
+
+inline void SpinlockMutex::lock()
+{
+	while (_flag.test_and_set(std::memory_order_acquire));
+}
+
+
+inline void SpinlockMutex::lock(long milliseconds)
+{
+	Timestamp now;
+	Timestamp::TimeDiff diff(Timestamp::TimeDiff(milliseconds)*1000);
+	while (_flag.test_and_set(std::memory_order_acquire))
+	{
+		if (now.isElapsed(diff)) throw TimeoutException();
+	}
+}
+
+
+inline bool SpinlockMutex::tryLock()
+{
+	return !_flag.test_and_set(std::memory_order_acquire);
+}
+
+
+inline bool SpinlockMutex::tryLock(long milliseconds)
+{
+	Timestamp now;
+	Timestamp::TimeDiff diff(Timestamp::TimeDiff(milliseconds)*1000);
+	while (_flag.test_and_set(std::memory_order_acquire))
+	{
+		if (now.isElapsed(diff)) return false;
+	}
+	return true;
+}
+
+
+inline void SpinlockMutex::unlock()
+{
+	_flag.clear(std::memory_order_release);
+}
+
+#endif // POCO_HAVE_STD_ATOMICS
+
+
+} // namespace Poco
+
+
+#endif // Foundation_Mutex_INCLUDED