From d882b22f2e870fa152f72b85cfd520bc16fcd34a Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Sun, 9 Aug 2020 22:04:54 +0800
Subject: Merge sync status into subscription hub.

---
 Timeline/ClientApp/src/app/data/SubscriptionHub.ts | 27 ++++++++++++++++++++++
 1 file changed, 27 insertions(+)

(limited to 'Timeline/ClientApp/src/app/data/SubscriptionHub.ts')

diff --git a/Timeline/ClientApp/src/app/data/SubscriptionHub.ts b/Timeline/ClientApp/src/app/data/SubscriptionHub.ts
index 7c24983b..e19c547c 100644
--- a/Timeline/ClientApp/src/app/data/SubscriptionHub.ts
+++ b/Timeline/ClientApp/src/app/data/SubscriptionHub.ts
@@ -6,11 +6,17 @@ export type Subscriber<TData> = (data: TData) => void;
 export interface ISubscriptionLine<TData> {
   readonly value: undefined | TData;
   next(value: TData): void;
+  readonly isSyncing: boolean;
+  beginSync(): void;
+  endSync(): void;
+  endSyncAndNext(value: TData): void;
 }
 
 export class SubscriptionLine<TData> implements ISubscriptionLine<TData> {
   private _current: TData | undefined = undefined;
 
+  private _syncing = false;
+
   private _observers: Subscriber<TData>[] = [];
 
   constructor(
@@ -38,6 +44,22 @@ export class SubscriptionLine<TData> implements ISubscriptionLine<TData> {
     this._observers.forEach((observer) => observer(value));
   }
 
+  get isSyncing(): boolean {
+    return this._syncing;
+  }
+
+  beginSync(): void {
+    if (!this._syncing) {
+      this._syncing = true;
+    }
+  }
+
+  endSync(): void {
+    if (this._syncing) {
+      this._syncing = false;
+    }
+  }
+
   get destroyable(): boolean {
     const customDestroyable = this.config?.destroyable;
 
@@ -46,6 +68,11 @@ export class SubscriptionLine<TData> implements ISubscriptionLine<TData> {
       (customDestroyable != null ? customDestroyable(this._current) : true)
     );
   }
+
+  endSyncAndNext(value: TData): void {
+    this.endSync();
+    this.next(value);
+  }
 }
 
 export class SubscriptionHub<TKey, TData> {
-- 
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