CallbackFilter (company license with source code)

CallbackFilter lets you monitor and control disk activity, track file and directory operations (create, read, write, rename etc.), alter file data, encrypt files and much more. CallbackFilter is an SDK (Software Development Kit) which lets your application intercept file operations in Windows operating systems. Your application is notified when some file operation (file open, file read, write, directory enumeration etc.) is performed. Besides plain notification, CallbackFilter lets your application decide, what to do with the request - the application can process the request, modify input or output data before or after the request is performed or even tell the operating system to decline / cancel the request. CallbackFilter provides rule-based interception and processing of the requests, thus offering powerful functionality with almost no coding. Rules both increase speed of request handling (as you can specify, what request types are filtered and what actions are performed for each filtered request).