99 lines
2.2 KiB
Swift
99 lines
2.2 KiB
Swift
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import Foundation
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import Observation
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@MainActor
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final class Listeners<T> {
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private var fns: [(id: UUID, fn: (T) -> Void)] = []
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func add(_ fn: @escaping (T) -> Void) -> () -> Void {
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let id = UUID()
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fns.append((id, fn))
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return { [weak self] in
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self?.fns.removeAll { $0.id == id }
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}
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}
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func send(_ value: T) {
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for entry in fns {
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entry.fn(value)
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}
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}
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}
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@MainActor
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@Observable
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final class Feed {
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private(set) var events: [ByreEvent] = []
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private(set) var ready = false
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let appended = Listeners<[ByreEvent]>()
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let streamed = Listeners<ByreEvent>()
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@ObservationIgnored private var last: Int64 = 0
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@ObservationIgnored private var buffer: [ByreEvent] = []
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@ObservationIgnored private var scheduled = false
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@ObservationIgnored private let shown: () -> Bool
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init(shown: @escaping () -> Bool) {
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self.shown = shown
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}
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func push(_ ev: ByreEvent) {
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if ev.seq == 0 && (!ready || !shown()) {
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return
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}
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buffer.append(ev)
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if ready && !scheduled {
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scheduled = true
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Task { @MainActor in
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self.flush()
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}
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}
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}
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func load(_ history: [ByreEvent]) {
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if ready {
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return
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}
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ready = true
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buffer = history + buffer
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flush()
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}
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func prepend(_ older: [ByreEvent]) {
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events.insert(contentsOf: older, at: 0)
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}
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private func flush() {
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scheduled = false
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let pending = buffer
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buffer = []
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var stored: [ByreEvent] = []
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for ev in pending {
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if ev.seq != 0 {
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stored.append(ev)
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continue
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}
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append(stored)
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stored = []
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if shown() {
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streamed.send(ev)
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}
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}
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append(stored)
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}
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private func append(_ batch: [ByreEvent]) {
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var fresh: [ByreEvent] = []
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for ev in batch where ev.seq > last {
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fresh.append(ev)
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last = ev.seq
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}
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if fresh.isEmpty {
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return
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}
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events.append(contentsOf: fresh)
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if shown() {
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appended.send(fresh)
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}
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}
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}
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