From 023f1d784720731fbcd3ac537ac1836b1c0c7797 Mon Sep 17 00:00:00 2001
From: Jung gyun Ahn <Junggyun.ahn@navercorp.com>
Date: Fri, 28 Jun 2024 20:52:59 +0900
Subject: [PATCH] Add lock (#185)

* Add a semaphore for serialize document update

* Open isApplyingChangePack variable

* Revert add isApplyingChagePack variable

* Add defer closure to signal semaphore.
---
 .../xcshareddata/swiftpm/Package.resolved     | 18 ++++++++++++++++
 Sources/Document/Document.swift               | 21 ++++++++++++++++---
 2 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/Examples/Example.xcworkspace/xcshareddata/swiftpm/Package.resolved b/Examples/Example.xcworkspace/xcshareddata/swiftpm/Package.resolved
index 705bc521..ec3d128d 100644
--- a/Examples/Example.xcworkspace/xcshareddata/swiftpm/Package.resolved
+++ b/Examples/Example.xcworkspace/xcshareddata/swiftpm/Package.resolved
@@ -36,6 +36,24 @@
         "version" : "1.1.0"
       }
     },
+    {
+      "identity" : "swift-docc-plugin",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-docc-plugin",
+      "state" : {
+        "revision" : "26ac5758409154cc448d7ab82389c520fa8a8247",
+        "version" : "1.3.0"
+      }
+    },
+    {
+      "identity" : "swift-docc-symbolkit",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-docc-symbolkit",
+      "state" : {
+        "revision" : "b45d1f2ed151d057b54504d653e0da5552844e34",
+        "version" : "1.0.0"
+      }
+    },
     {
       "identity" : "swift-log",
       "kind" : "remoteSourceControl",
diff --git a/Sources/Document/Document.swift b/Sources/Document/Document.swift
index c3a697d6..ac062c7f 100644
--- a/Sources/Document/Document.swift
+++ b/Sources/Document/Document.swift
@@ -16,6 +16,7 @@
 
 import Combine
 import Foundation
+import Semaphore
 
 /**
  * `DocumentOptions` are the options to create a new document.
@@ -99,6 +100,8 @@ public actor Document {
      */
     private var presences: [ActorID: StringValueTypeDictionary]
 
+    private let workSemaphore = AsyncSemaphore(value: 1)
+
     public init(key: String) {
         self.init(key: key, opts: DocumentOptions(disableGC: false))
     }
@@ -120,7 +123,13 @@ public actor Document {
     /**
      * `update` executes the given updater to update this document.
      */
-    public func update(_ updater: (_ root: JSONObject, _ presence: inout Presence) throws -> Void, _ message: String? = nil) throws {
+    public func update(_ updater: (_ root: JSONObject, _ presence: inout Presence) async throws -> Void, _ message: String? = nil) async throws {
+        await self.workSemaphore.wait()
+
+        defer {
+            self.workSemaphore.signal()
+        }
+
         guard self.status != .removed else {
             throw YorkieError.documentRemoved(message: "\(self) is removed.")
         }
@@ -141,7 +150,7 @@ public actor Document {
 
         var presence = Presence(changeContext: context, presence: self.clone?.presences[actorID] ?? [:])
 
-        try updater(proxy, &presence)
+        try await updater(proxy, &presence)
 
         self.clone?.presences[actorID] = presence.presence
 
@@ -250,7 +259,13 @@ public actor Document {
      *
      * - Parameter pack: change pack
      */
-    func applyChangePack(_ pack: ChangePack) throws {
+    func applyChangePack(_ pack: ChangePack) async throws {
+        await self.workSemaphore.wait()
+
+        defer {
+            self.workSemaphore.signal()
+        }
+
         if let snapshot = pack.getSnapshot() {
             try self.applySnapshot(pack.getCheckpoint().getServerSeq(), snapshot)
         } else if pack.hasChanges() {