114 lines
6.3 KiB
TypeScript
114 lines
6.3 KiB
TypeScript
/** A durable preference draft keeps its original CAS base until the user resolves a conflict. */
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export interface LogicalRecord<T> { schema: 1; kind: string; id: string; data: T }
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export interface RecordDocument<T> { record: LogicalRecord<T>; hash: string; file_id: string }
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interface Draft<T> { record: LogicalRecord<T>; expected: string; operation_id: string }
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interface Options<T> {
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vaultId: string; kind: string; id: string; read(): T; apply(data: T): void | Promise<void>
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invoke<R>(command: string, args: Record<string, unknown>): Promise<R>
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storage: Pick<Storage, 'getItem' | 'setItem' | 'removeItem'>; changed?(): void
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}
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export class RecordBinding<T> {
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private draft: Draft<T> | null = null
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private remote: RecordDocument<T> | null = null
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private running = false
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private active: Promise<void> | null = null
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private restored = false
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private invalidDraft = false
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private stopped = false
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private initialized = false
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private appliedHash: string | null = null
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error = ''
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constructor(private options: Options<T>) {
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try {
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const value = JSON.parse(options.storage.getItem(this.key) ?? 'null') as Draft<T> | null
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if (value && (value.record?.schema !== 1 || value.record.kind !== options.kind || value.record.id !== options.id || !value.record.data || typeof value.record.data !== 'object' || typeof value.expected !== 'string' || !/^(?:[0-9a-f]{64})?$/.test(value.expected) || typeof value.operation_id !== 'string' || !/^[0-9a-f-]{36}$/.test(value.operation_id))) throw new Error('invalid draft')
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this.draft = value; this.restored = value !== null
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} catch { this.error = 'PREFERENCE_DRAFT_INVALID'; this.invalidDraft = true }
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}
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private get key() { return `opennexus-record-draft:${this.options.vaultId}:${this.options.kind}:${this.options.id}` }
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private persist(draft = this.draft) {
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try {
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if (draft) this.options.storage.setItem(this.key, JSON.stringify(draft))
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else this.options.storage.removeItem(this.key)
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} catch { this.error = 'PREFERENCE_DRAFT_STORE_FAILED'; this.options.changed?.(); throw new Error(this.error) }
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this.options.changed?.()
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}
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get conflicted() { return this.error === 'REVISION_CONFLICT' }
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get hasDraft() { return this.draft !== null || this.invalidDraft }
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stop() { this.stopped = true }
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capture() {
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if (this.stopped) return
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const data = JSON.parse(JSON.stringify(this.options.read())) as T
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if (!this.draft && this.remote && JSON.stringify(data) === JSON.stringify(this.remote.record.data)) return
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// New edits while a request runs get a new operation, but preserve the unresolved base.
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this.draft = { record: { schema: 1, kind: this.options.kind, id: this.options.id, data }, expected: this.draft?.expected ?? this.remote?.hash ?? '', operation_id: crypto.randomUUID() }
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this.restored = false; this.invalidDraft = false
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try { this.persist(); if (this.error === 'PREFERENCE_DRAFT_STORE_FAILED') this.error = '' } catch { this.error = 'PREFERENCE_DRAFT_STORE_FAILED'; this.options.changed?.() }
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}
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async seed() {
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await this.poll()
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if (!this.stopped && this.initialized && !this.remote && !this.draft) { this.capture(); await this.poll() }
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}
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poll(): Promise<void> {
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if (this.stopped) return Promise.resolve()
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if (this.active) return this.active
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this.active = this.run().finally(() => { this.active = null })
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return this.active
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}
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private async run() {
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if (this.running || this.stopped || this.invalidDraft || this.error === 'PREFERENCE_DRAFT_STORE_FAILED') return
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this.running = true
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try {
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this.remote = await this.options.invoke<RecordDocument<T> | null>('record_get', { request: { vault_id: this.options.vaultId, kind: this.options.kind, id: this.options.id } })
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if (this.stopped) return
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this.initialized = true
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if (this.draft) {
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if (this.restored) { this.restored = false; await this.options.apply(this.draft.record.data) }
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if (this.stopped || this.conflicted) return
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const draft = this.draft
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const committed = await this.options.invoke<RecordDocument<T>>('record_write', { request: { vault_id: this.options.vaultId, ...draft } })
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this.remote = committed
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if (this.draft.operation_id === draft.operation_id) {
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this.persist(null); this.draft = null; this.appliedHash = committed.hash
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} else {
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// The next local edit follows the just-confirmed predecessor, not its older CAS base.
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this.draft.expected = committed.hash; this.persist()
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}
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} else if (this.remote && this.remote.hash !== this.appliedHash) {
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await this.options.apply(this.remote.record.data)
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this.appliedHash = this.remote.hash
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}
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this.error = ''
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} catch (error) { this.error = error instanceof Error ? error.message : 'PREFERENCE_SYNC_FAILED' }
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finally { this.running = false; this.options.changed?.() }
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}
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async keepLocal() {
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await this.active
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if (this.running || this.stopped) return
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this.running = true
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try {
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if (this.invalidDraft) this.capture()
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if (!this.draft) return
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const remote = await this.options.invoke<RecordDocument<T> | null>('record_get', { request: { vault_id: this.options.vaultId, kind: this.options.kind, id: this.options.id } })
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if (this.stopped) return
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this.remote = remote; this.draft.expected = remote?.hash ?? ''; this.draft.operation_id = crypto.randomUUID(); this.error = ''; this.persist()
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} finally { this.running = false }
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await this.poll()
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}
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async useRemote() {
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await this.active
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if (this.running || this.stopped) return
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this.running = true
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try {
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const decision = this.draft?.operation_id
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const remote = await this.options.invoke<RecordDocument<T> | null>('record_get', { request: { vault_id: this.options.vaultId, kind: this.options.kind, id: this.options.id } })
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if (this.stopped) return
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if (this.draft?.operation_id !== decision) { this.error = 'PREFERENCE_CHANGED'; this.options.changed?.(); return }
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if (!remote) { this.error = 'PREFERENCE_REMOTE_MISSING'; this.options.changed?.(); return }
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this.options.storage.removeItem(this.key)
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this.draft = null; this.invalidDraft = false; this.error = ''; this.remote = remote; this.options.changed?.()
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await this.options.apply(remote.record.data); this.appliedHash = remote.hash
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} finally { this.running = false }
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}
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}
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