File size: 1,981 Bytes
064bfd6 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 | /**
* State machine for gating message writes during an initial flush.
*
* When a bridge session starts, historical messages are flushed to the
* server via a single HTTP POST. During that flush, new messages must
* be queued to prevent them from arriving at the server interleaved
* with the historical messages.
*
* Lifecycle:
* start() → enqueue() returns true, items are queued
* end() → returns queued items for draining, enqueue() returns false
* drop() → discards queued items (permanent transport close)
* deactivate() → clears active flag without dropping items
* (transport replacement — new transport will drain)
*/
export class FlushGate<T> {
private _active = false
private _pending: T[] = []
get active(): boolean {
return this._active
}
get pendingCount(): number {
return this._pending.length
}
/** Mark flush as in-progress. enqueue() will start queuing items. */
start(): void {
this._active = true
}
/**
* End the flush and return any queued items for draining.
* Caller is responsible for sending the returned items.
*/
end(): T[] {
this._active = false
return this._pending.splice(0)
}
/**
* If flush is active, queue the items and return true.
* If flush is not active, return false (caller should send directly).
*/
enqueue(...items: T[]): boolean {
if (!this._active) return false
this._pending.push(...items)
return true
}
/**
* Discard all queued items (permanent transport close).
* Returns the number of items dropped.
*/
drop(): number {
this._active = false
const count = this._pending.length
this._pending.length = 0
return count
}
/**
* Clear the active flag without dropping queued items.
* Used when the transport is replaced (onWorkReceived) — the new
* transport's flush will drain the pending items.
*/
deactivate(): void {
this._active = false
}
}
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