Reconsider the process of cleaning existing files

Problem/Motivation

Currently, it is possible to start a cleaning operation by filling in a file system location. The process then tries to load a file entity based on the file URI before doing any cleaning.

• Should we consider files that are in the filesystem, but not in the Drupal database? If so, should this be configurable (e.g. checkbox stating "Only clean files known to Drupal")?
• At present, strange things happen when you start a cleaning operation for another (or even the same) file system location. In terms of actually cleaning the files It works fine, but progress reporting is broken, because it only keeps track of the total of a single location (the last one to have been submitted). It then uses the total length of the queue (containing entries for every file for every location the form was submitted for) to compare to that total, which will go wrong.
• It is not currently possible to clean files in other than the public file system, most notably private files.
• Should we not simply clean al files known to Drupal and/or within file system locations controlled by Drupal?

Proposed resolution

This probably should result in multiple issues when we actually decide what approach to take.

Remaining tasks

• Decide on what approach to take
• Create child issues

User interface changes

Not determined yet.

API changes

Not determined yet.

Data model changes

None, most likely.