Module engine 

The read operations every front end shares, over one client and one set of request limits.

Reader is the reading strategy for one device: each request waits for its turn at the device’s gate and the global rate cap (RequestLimits), a property list goes by ReadPropertyMultiple with a ReadProperty fallback, and the Object_List falls back to element-by-element reads. The TUI’s browser, watch list and write previews use it directly, with their own stop flags.

Engine is the facade the MCP server builds on: it owns the client, the limits and the per-device memory of RPM refusals, and offers the read operations as plain async calls on a device instance. A device is looked up in the client’s discovery table, so routed devices work as the *_from_device client calls route them. Cancelling a call means dropping its future: a turn’s wait is cancel-safe, and a request already sent is abandoned to the client’s transaction state machine.

Structs

DeviceSummary

A device’s DEVICE_PROPERTIES as read.

Engine

The read operations over one client, shared by every caller.

ListRead

How an Object_List read went.

PropertyRead

One object’s properties as read.

Reader

Reads one device, one request at a time, each with its turn at the device’s gate and the global rate cap.

Enums

Halt

Why a read stopped.

Naming

How a best-effort naming read ended: it never fails the read it names, but a request it lost to a timeout is still a timeout (#2131).

ReadVia

How a property list was read.

RpmFailure

What an RPM failure says about trying ReadProperty instead.

Wanted

What Reader::properties reads.

WhoIsScope

Where a Who-Is goes.

Constants

DEVICE_PROPERTIES

The Device properties a device summary reads (Clause 12.11): who made it, what it runs, and what it can do. The TUI’s device card shows them.

MAX_OBJECTS

Elements a device’s Object_List may claim before the browser stops reading it; a device holds far fewer.

Functions

network_of

The network device is on, for limits that pace networks: its routed network, or 0 for the local one. None when the limits don’t pace networks, so the lookup is skipped, or the device isn’t known.

rpm_failure

Classify an RPM failure.

timed_out

True when error says the request timed out: the client’s own timeout, or the transaction state machine giving up on its retries. A transport failure is unreachable but not a timeout.

unreachable

True when error says the device, or the way to it, isn’t answering: a timeout or a transport failure. Reading on would only time out again.