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/Net/src/FilePartSource.cpp

@@ -0,0 +1,87 @@
+//
+// FilePartSource.cpp
+//
+// Library: Net
+// Package: Messages
+// Module:  FilePartSource
+//
+// Copyright (c) 2005-2006, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// SPDX-License-Identifier:	BSL-1.0
+//
+
+
+#include "Poco/Net/FilePartSource.h"
+#include "Poco/Path.h"
+#include "Poco/File.h"
+#include "Poco/Exception.h"
+
+
+using Poco::Path;
+using Poco::OpenFileException;
+
+
+namespace Poco {
+namespace Net {
+
+
+FilePartSource::FilePartSource(const std::string& path):
+	_path(path), _istr(path)
+{
+	Path p(path);
+	_filename = p.getFileName();
+	if (!_istr.good())
+		throw OpenFileException(path);
+}
+
+
+FilePartSource::FilePartSource(const std::string& path, const std::string& mediaType):
+	PartSource(mediaType),
+	_path(path),
+	_istr(path)
+{
+	Path p(path);
+	_filename = p.getFileName();
+	if (!_istr.good())
+		throw OpenFileException(path);
+}
+
+
+FilePartSource::FilePartSource(const std::string& path, const std::string& filename, const std::string& mediaType):
+	PartSource(mediaType),
+	_path(path),
+	_filename(filename),
+	_istr(path)
+{
+	Path p(path);
+	if (!_istr.good())
+		throw OpenFileException(path);
+}
+
+
+FilePartSource::~FilePartSource()
+{
+}
+
+
+std::istream& FilePartSource::stream()
+{
+	return _istr;
+}
+
+
+const std::string& FilePartSource::filename() const
+{
+	return _filename;
+}
+
+
+std::streamsize FilePartSource::getContentLength() const
+{
+	Poco::File p(_path);
+	return static_cast<std::streamsize>(p.getSize());
+}
+
+
+} } // namespace Poco::Net