ios: close database connections when app is terminating (#3188)

* ios: close database connections when app is terminating

* update

* remove ()

* close when suspended too

* additional check

* fix

* refactore

* reset "terminating" flag

apps/ios/Shared/Model/SuspendChat.swift

@@ -19,7 +19,11 @@ let bgSuspendTimeout: Int = 5 // seconds
 let terminationTimeout: Int = 3 // seconds
 
 private func _suspendChat(timeout: Int) {
-    if ChatModel.ok {
+    // this is a redundant check to prevent logical errors, like the one fixed in this PR
+    let state = appStateGroupDefault.get()
+    if !state.canSuspend {
+        logger.error("_suspendChat called, current state: \(state.rawValue, privacy: .public)")
+    } else if ChatModel.ok {
         appStateGroupDefault.set(.suspending)
         apiSuspendChat(timeoutMicroseconds: timeout * 1000000)
         let endTask = beginBGTask(chatSuspended)
@@ -31,9 +35,7 @@ private func _suspendChat(timeout: Int) {
 
 func suspendChat() {
     suspendLockQueue.sync {
-        if appStateGroupDefault.get() != .stopped {
-            _suspendChat(timeout: appSuspendTimeout)
-        }
+        _suspendChat(timeout: appSuspendTimeout)
     }
 }
 
@@ -45,15 +47,25 @@ func suspendBgRefresh() {
     }
 }
 
+private var terminating = false
+
 func terminateChat() {
+    logger.debug("terminateChat")
     suspendLockQueue.sync {
         switch appStateGroupDefault.get() {
         case .suspending:
             // suspend instantly if already suspending
             _chatSuspended()
+            // when apiSuspendChat is called with timeout 0, it won't send any events on suspension
             if ChatModel.ok { apiSuspendChat(timeoutMicroseconds: 0) }
-        case .stopped: ()
+            chatCloseStore()
+        case .suspended:
+            chatCloseStore()
+        case .stopped:
+            chatCloseStore()
         default:
+            terminating = true
+            // the store will be closed in _chatSuspended when event is received
             _suspendChat(timeout: terminationTimeout)
         }
     }
@@ -73,10 +85,14 @@ private func _chatSuspended() {
     if ChatModel.shared.chatRunning == true {
         ChatReceiver.shared.stop()
     }
+    if terminating {
+         chatCloseStore()
+    }
 }
 
 func activateChat(appState: AppState = .active) {
     logger.debug("DEBUGGING: activateChat")
+    terminating = false
     suspendLockQueue.sync {
         appStateGroupDefault.set(appState)
         if ChatModel.ok { apiActivateChat() }
@@ -85,6 +101,7 @@ func activateChat(appState: AppState = .active) {
 }
 
 func initChatAndMigrate(refreshInvitations: Bool = true) {
+    terminating = false
     let m = ChatModel.shared
     if (!m.chatInitialized) {
         do {
@@ -97,6 +114,7 @@ func initChatAndMigrate(refreshInvitations: Bool = true) {
 }
 
 func startChatAndActivate() {
+    terminating = false
     logger.debug("DEBUGGING: startChatAndActivate")
     if ChatModel.shared.chatRunning == true {
         ChatReceiver.shared.start()

apps/ios/SimpleXChat/API.swift

@@ -50,6 +50,13 @@ public func chatMigrateInit(_ useKey: String? = nil, confirmMigrations: Migratio
     return result
 }
 
+public func chatCloseStore() {
+    let err = fromCString(chat_close_store(getChatCtrl()))
+    if err != "" {
+        logger.error("chatCloseStore error: \(err)")
+    }
+}
+
 public func resetChatCtrl() {
     chatController = nil
     migrationResult = nil

apps/ios/SimpleXChat/AppGroup.swift

@@ -80,6 +80,14 @@ public enum AppState: String {
         default: return false
         }
     }
+
+    public var canSuspend: Bool {
+        switch self {
+        case .active: true
+        case .bgRefresh: true
+        default: false
+        }
+    }
 }
 
 public enum DBContainer: String {

apps/ios/SimpleXChat/SimpleX.h

@@ -17,6 +17,7 @@ typedef void* chat_ctrl;
 
 // the last parameter is used to return the pointer to chat controller
 extern char *chat_migrate_init(char *path, char *key, char *confirm, chat_ctrl *ctrl);
+extern char *chat_close_store(chat_ctrl ctl);
 extern char *chat_send_cmd(chat_ctrl ctl, char *cmd);
 extern char *chat_recv_msg(chat_ctrl ctl);
 extern char *chat_recv_msg_wait(chat_ctrl ctl, int wait);