From 1e280fb7e141f83f6c08e764bec2ba110221f90e Mon Sep 17 00:00:00 2001
From: Stanislav Dmitrenko <7953703+avently@users.noreply.github.com>
Date: Wed, 5 Apr 2023 20:53:35 +0300
Subject: [PATCH] android: prevent possible race in chat items (#2148)

* android: prevent possible race in chat items

* change
---
 .../java/chat/simplex/app/model/ChatModel.kt  | 29 ++++++++++---------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/apps/android/app/src/main/java/chat/simplex/app/model/ChatModel.kt b/apps/android/app/src/main/java/chat/simplex/app/model/ChatModel.kt
index e2e1446dad..7646abe8a2 100644
--- a/apps/android/app/src/main/java/chat/simplex/app/model/ChatModel.kt
+++ b/apps/android/app/src/main/java/chat/simplex/app/model/ChatModel.kt
@@ -192,10 +192,13 @@ class ChatModel(val controller: ChatController) {
     // add to current chat
     if (chatId.value == cInfo.id) {
       withContext(Dispatchers.Main) {
-        if (chatItems.lastOrNull()?.id == ChatItem.TEMP_LIVE_CHAT_ITEM_ID) {
-          chatItems.add(kotlin.math.max(0, chatItems.lastIndex), cItem)
-        } else {
-          chatItems.add(cItem)
+        // Prevent situation when chat item already in the list received from backend
+        if (chatItems.none { it.id == cItem.id }) {
+          if (chatItems.lastOrNull()?.id == ChatItem.TEMP_LIVE_CHAT_ITEM_ID) {
+            chatItems.add(kotlin.math.max(0, chatItems.lastIndex), cItem)
+          } else {
+            chatItems.add(cItem)
+          }
         }
       }
     }
@@ -222,19 +225,19 @@ class ChatModel(val controller: ChatController) {
       res = true
     }
     // update current chat
-    if (chatId.value == cInfo.id) {
-      val itemIndex = chatItems.indexOfFirst { it.id == cItem.id }
-      if (itemIndex >= 0) {
-        chatItems[itemIndex] = cItem
-        return false
-      } else {
-        withContext(Dispatchers.Main) {
+    return if (chatId.value == cInfo.id) {
+      withContext(Dispatchers.Main) {
+        val itemIndex = chatItems.indexOfFirst { it.id == cItem.id }
+        if (itemIndex >= 0) {
+          chatItems[itemIndex] = cItem
+          false
+        } else {
           chatItems.add(cItem)
+          true
         }
-        return true
       }
     } else {
-      return res
+      res
     }
   }