Refactor DataBase class and archive/remote modules

[Zeitsperre]

Proposal

There is a very old and unmaintained DataBase-related class (miranda.data) used for interacting with remote servers. This functionality is only useful when combined with miranda.archive and miranda.remote to perform actions such as ensuring that adequate space is available before transferring data. Unfortunately, a significant effort is needed to bring up the quality and usability of these classes/functions.

Approach

These modules and classes need to be completely refactored and documented. The idea behind this section of Miranda is to facilitate an easier approach to archiving obsolete data for long-term storage. An ideal approach to archiving (as Miranda are presently organized) would be as follows:

• Folders slated for archiving are identified
• miranda.archive utilities are used for creating file groupings. Groupings follow a nestec dictionary-based schema: top-level keys are archives, all subsequent keys are folder-structure of archive, drilled-down values are files.
• If transfer is remote, miranda.remote.Connection is used to establish a connection with an external server.
  • If remote folders are needed: miranda.remote.ops.create_remote_directory
• miranda.data.DataBase is used with a Connection instance to peform checks prior to transfer of files.
  • Transfer function: miranda.remote.ops.transfer_file

The current approach clearly does not make this obvious. There should be a regrouping of function and utilities. There may even potential for moving some functions to the miranda.io module.