Module rail_layout 

The community rail’s arrangement: an ordered list of communities and the folders that group them, synced across the account’s own devices.

On the wire it is a crate::synced_prefs::Pref::Rail document — a self-encrypted kind 30078 with the d tag vector/rail — deliberately separate from the Community List, which carries join material. A drag is the most frequent write the UI makes, and the list that holds keys is the last document that should absorb that traffic: it is fragmented against a byte ceiling, and it has already been wedged once by growing past one. Here a failed write costs a session of default ordering and nothing else.

  kind:    30078 (APPLICATION_SPECIFIC)
  tags:    ["d", "vector/rail"]
  content: nip44(self, {"v":1,"nodes":[
             {"type":"item","key":"<community-id>"},
             {"type":"folder","id":"…","name":"Work","hue":210,"keys":["…","…"]}
           ]})

Keys are opaque and never dropped. A community this device has not synced yet keeps its place through every read and republish; rendering simply skips what it cannot resolve. Dropping unknown keys would let the device that knows least flatten everyone else’s folders. The single exception is RailLayout::remove_key, called when the user LEAVES a community: without it a later rejoin would silently reappear inside its old folder at its old index.

Every operation here is pure, so the arrangement can be tested without a relay and the UI stays a view over it.

Structs

RailLayout

The stored arrangement.

Enums

RailAnchor

A top-level row, named so a drop can say “before this one” without caring whether it is a community or a folder.

RailDrag

What a drag picked up.

RailDrop

Where a drag let go.

RailNode

One row of the rail: a community on its own, or a folder holding several.

Constants

RAIL_VERSION

The version this build writes. A document from the future is read, rendered and republished untouched, but never EDITED: an older build cannot know what

Functions

new_folder_id

A fresh folder id. Short and random rather than sequential: two devices can each make a folder before either has seen the other’s, and an index would have them collide into one.