Disable various updates using --offline=CACHE_UPDATES

[simon04]

On slow internet connections, one would like to not fetch any updates. This includes plugins, imagery backgrounds, custom styles (especially their icon sets), presets, etc.

Specifying --offline=updates should not ask for or perform any updates. CachedFile should give the cached version w/o determining whether it's still up-to-date. The goal is to avoid unnecessary network traffic when JOSM is started with this option.

This is similar to --offline=josm_website, but user initiated network access (such as help) should not be disabled.

[Don-vip]

I'm not sure if --offlines=updates is the right way to do it or if we should create a new parameter (--no-updates?). The offline value is more a functional download source rather than a technical mode.

[simon04]

NetworkManager and OnlineResource are working together so nicely. Thus, I'll be (a bit mis)using --offline for this purpose.

$ java -jar josm-latest.jar --offline=CACHE_UPDATES 
2020-05-16 21:54:42.905 WARNING: JOSM is running in offline mode. This resource will not be available: Cache updates
2020-05-16 21:54:44.754 WARNING: Cache update for https://josm.openstreetmap.de/maps not available (offline mode)

[simon04]

In 16430/josm:

fix #18162, see #18712 - Add --offline=CACHE_UPDATES to disable updates of CachedFiles

This includes imagery index, custom styles, presets.

[skyper]

The man page needs to be adjusted, too.

[simon04]

In 16446/josm:

see #18162 - Update man page for --offline

[simon04]

Replying to skyper:

The man page needs to be adjusted, too.

Thank you for the reminder!

[simon04]

In 16964/josm:

fix #13586, see #18162 - Preferences: do not update source entries automatically when --offline=CACHE_UPDATES