Merge pull request #219 from synonymdev/backup-event-debounce

Debounce backup state events to react native

lib/android/src/main/java/com/reactnativeldk/Helpers.kt

@@ -1,4 +1,6 @@
 package com.reactnativeldk
+import android.os.Handler
+import android.os.Looper
 import com.facebook.react.bridge.*
 import org.json.JSONObject
 import org.ldk.enums.Currency
@@ -8,6 +10,7 @@ import java.io.File
 import java.io.FileOutputStream
 import java.net.URL
 import java.nio.channels.Channels
+import java.util.Date
 
 fun handleResolve(promise: Promise, res: LdkCallbackResponses) {
     if (res != LdkCallbackResponses.log_write_success) {
@@ -204,6 +207,22 @@ fun WritableMap.putHexString(key: String, bytes: ByteArray?) {
     }
 }
 
+/**
+ * Adds a Date object into the map.
+ * If the date is not null, it is converted to a double representing the unix timestamp.
+ * If it's null, a null value is added to the map.
+ *
+ * @param key The key under which the date will be stored in the map.
+ * @param date The date to be stored in the map. Can be null.
+ */
+fun WritableMap.putDateOrNull(key: String, date: Date?) {
+    if (date != null) {
+        putDouble(key, date.time.toDouble())
+    } else {
+        putNull(key)
+    }
+}
+
 fun WritableArray.pushHexString(bytes: ByteArray) {
     pushString(bytes.hexEncodedString())
 }
@@ -502,4 +521,24 @@ fun mergeObj(obj1: JSONObject, obj2: HashMap<String, Any>): HashMap<String, Any>
     }
 
     return newObj
-}
+}
+
+object UiThreadDebouncer {
+    private val pending = hashMapOf<String, Runnable>()
+    private val handler = Handler(Looper.getMainLooper())
+
+    /**
+     * Used to debounce an [action] function call to be executed after a delay on the main thread
+     *
+     * @param interval The delay in milliseconds after which the action will be executed. Default value is 250ms.
+     * @param key The unique identifier for the action to be debounced. If an action with the same key is already pending, it will be cancelled.
+     * @param action The function to be executed after the interval.
+     */
+    fun debounce(interval: Long = 250, key: String, action: () -> Unit) {
+        pending[key]?.let { handler.removeCallbacks(it) }
+        val runnable = Runnable(action)
+        pending[key] = runnable
+
+        handler.postDelayed(runnable, interval)
+    }
+}

lib/android/src/main/java/com/reactnativeldk/classes/BackupClient.kt

@@ -1,10 +1,13 @@
 package com.reactnativeldk.classes
+
 import com.facebook.react.bridge.Arguments
 import com.facebook.react.bridge.WritableMap
+import com.reactnativeldk.UiThreadDebouncer
 import com.reactnativeldk.EventTypes
 import com.reactnativeldk.LdkEventEmitter
 import com.reactnativeldk.hexEncodedString
 import com.reactnativeldk.hexa
+import com.reactnativeldk.putDateOrNull
 import org.json.JSONObject
 import org.ldk.structs.Result_StrSecp256k1ErrorZ.Result_StrSecp256k1ErrorZ_OK
 import org.ldk.structs.UtilMethods
@@ -61,17 +64,9 @@ data class BackupFileState(
     val encoded: WritableMap
         get() {
             val body = Arguments.createMap()
-            body.putInt("lastQueued", lastQueued.time.toInt())
-            if (lastPersisted != null) {
-                body.putInt("lastPersisted", lastPersisted!!.time.toInt())
-            } else {
-                body.putNull("lastPersisted")
-            }
-            if (lastFailed != null) {
-                body.putInt("lastFailed", lastFailed!!.time.toInt())
-            } else {
-                body.putNull("lastFailed")
-            }
+            body.putDouble("lastQueued", lastQueued.time.toDouble())
+            body.putDateOrNull("lastPersisted", lastPersisted)
+            body.putDateOrNull("lastFailed", lastFailed)
             if (lastErrorMessage != null) {
                 body.putString("lastErrorMessage", lastErrorMessage)
             } else {
@@ -592,10 +587,9 @@ class BackupClient {
                 body.putMap(key, state.encoded)
             }
 
-            LdkEventEmitter.send(
-                EventTypes.backup_state_update,
-                body
-            )
+            UiThreadDebouncer.debounce(interval = 250, key = "backupStateUpdate") {
+                LdkEventEmitter.send(EventTypes.backup_state_update, body)
+            }
 
             backupStateLock.unlock()
         }

lib/ios/Classes/BackupClient.swift

@@ -152,7 +152,7 @@ class BackupClient {
     }
 
     static var backupState: [String: BackupFileState] = [:]
-         
+
     static func setup(secretKey: [UInt8], pubKey: [UInt8], network: String, server: String, serverPubKey: String) throws {
         guard getNetwork(network) != nil else {
             throw BackupError.invalidNetwork
@@ -195,9 +195,9 @@ class BackupClient {
         guard let key = Self.encryptionKey else {
             throw BackupError.requiresSetup
         }
-                
+
         let sealedBox = try AES.GCM.seal(blob, using: key)
-
+        
         return sealedBox.combined!
     }
 
@@ -209,7 +209,7 @@ class BackupClient {
         guard let key = Self.encryptionKey else {
             throw BackupError.requiresSetup
         }
-                
+
         //Remove appended 12 bytes nonce and 16 byte trailing tag
         let encryptedData: Data = {
             var bytes = blob.subdata(in: 12..<blob.count)
@@ -223,7 +223,7 @@ class BackupClient {
         do {
             let sealedBox = try AES.GCM.SealedBox(nonce: .init(data: nonce), ciphertext: encryptedData, tag: tag)
             let decryptedData = try AES.GCM.open(sealedBox, using: key)
-                        
+
             return decryptedData
         } catch {
             if let ce = error as? CryptoKitError {
@@ -256,7 +256,7 @@ class BackupClient {
             throw persistError
         }
     }
-
+    
     fileprivate static func persist(_ label: Label, _ bytes: [UInt8]) throws {
         struct PersistResponse: Codable {
             let success: Bool
@@ -267,25 +267,25 @@ class BackupClient {
             LdkEventEmitter.shared.send(withEvent: .native_log, body: "Skipping remote backup for \(label.string)")
             return
         }
-
+        
         guard let pubKey, let serverPubKey else {
             throw BackupError.requiresSetup
         }
-
+        
         let pubKeyHex = Data(pubKey).hexEncodedString()
         let encryptedBackup = try encrypt(Data(bytes))
         let signedHash = try sign(hash(encryptedBackup))
 
         //Hash of pubkey+timestamp
         let clientChallenge = hash("\(pubKeyHex)\(Date().timeIntervalSince1970)".data(using: .utf8)!)
-                
+
         var request = URLRequest(url: try backupUrl(.persist, label))
         request.httpMethod = "POST"
         request.setValue("application/octet-stream", forHTTPHeaderField: "Content-Type")
         request.setValue(signedHash, forHTTPHeaderField: "Signed-Hash")
         request.setValue(pubKeyHex, forHTTPHeaderField: "Public-Key")
         request.setValue(clientChallenge, forHTTPHeaderField: "Challenge")
-
+        
         request.httpBody = encryptedBackup
 
         var requestError: Error?
@@ -333,7 +333,7 @@ class BackupClient {
         guard verifySignature(message: clientChallenge, signature: persistResponse.signature, pubKey: serverPubKey) else {
             throw BackupError.serverChallengeResponseFailed
         }
-
+        
         LdkEventEmitter.shared.send(withEvent: .native_log, body: "Remote persist success for \(label.string)")
     }
 
@@ -436,10 +436,10 @@ class BackupClient {
 
     static func retrieveCompleteBackup() throws -> CompleteBackup {
         let backedUpFilenames = try listFiles()
-                
+
         var allFiles: [String: Data] = [:]
         var channelFiles: [String: Data] = [:]
-
+        
         //Fetch each file's data
         for fileName in backedUpFilenames.list {
             guard fileName != "\(Label.ping.string).bin" else {
@@ -482,7 +482,7 @@ class BackupClient {
         guard let secretKey else {
             throw BackupError.requiresSetup
         }
-
+        
         let fullMessage = "\(signedMessagePrefix)\(message)"
         let signed = Bindings.swiftSign(msg: Array(fullMessage.utf8), sk: secretKey)
         if let _ = signed.getError() {
@@ -511,7 +511,7 @@ class BackupClient {
         guard let pubKey else {
             throw BackupError.requiresSetup
         }
-
+        
         //Fetch challenge with signed timestamp as nonce
         let pubKeyHex = Data(pubKey).hexEncodedString()
         let timestamp = String(Date().timeIntervalSince1970)
@@ -520,7 +520,7 @@ class BackupClient {
             "timestamp": timestamp,
             "signature": try sign(timestamp)
         ]
-
+        
         struct FetchChallengeResponse: Codable {
             let challenge: String
         }
@@ -530,9 +530,9 @@ class BackupClient {
         request.httpMethod = "POST"
         request.setValue("application/json", forHTTPHeaderField: "Content-Type")
         request.setValue(pubKeyHex, forHTTPHeaderField: "Public-Key")
-                
+
         request.httpBody = try JSONSerialization.data(withJSONObject: payload)
-
+        
         var requestError: Error?
         let semaphore = DispatchSemaphore(value: 0)
         let task = URLSession.shared.dataTask(with: request) { (data, response, error) in
@@ -561,12 +561,12 @@ class BackupClient {
 
         task.resume()
         semaphore.wait()
-                
+
         if let error = requestError {
             LdkEventEmitter.shared.send(withEvent: .native_log, body: "Fetch server challenge failed. \(error.localizedDescription)")
             throw error
         }
-            
+
         guard let fetchChallengeResponse else {
             throw BackupError.missingResponse
         }
@@ -579,9 +579,9 @@ class BackupClient {
         fetchRequest.httpMethod = "POST"
         fetchRequest.setValue("application/json", forHTTPHeaderField: "Content-Type")
         fetchRequest.setValue(pubKeyHex, forHTTPHeaderField: "Public-Key")
-                
+
         fetchRequest.httpBody = try JSONSerialization.data(withJSONObject: fetchPayload)
-
+        
         var fetchRequestError: Error?
         var fetchBearerResponse: BackupRetrieveBearer?
         let fetchSemaphore = DispatchSemaphore(value: 0)
@@ -611,7 +611,7 @@ class BackupClient {
 
         fetchTask.resume()
         fetchSemaphore.wait()
-                
+
         if let error = fetchRequestError {
             LdkEventEmitter.shared.send(withEvent: .native_log, body: "Fetch bearer token failed. \(error.localizedDescription)")
             throw error
@@ -634,7 +634,6 @@ extension BackupClient {
             return
         }
 
-        //All updates on main queue
         DispatchQueue.main.async {
             backupState[key] = backupState[key] ?? .init(lastQueued: Date())
 
@@ -657,7 +656,9 @@ extension BackupClient {
                 body[key] = backupState[key]!.encoded
             }
 
-            LdkEventEmitter.shared.send(withEvent: .backup_state_update, body: body)
+            debounce(interval: 0.25, key: "backup-state-event") {
+                LdkEventEmitter.shared.send(withEvent: .backup_state_update, body: body)
+            }()
         }
     }
 

lib/ios/Helpers.swift

@@ -556,3 +556,23 @@ extension String {
             .reduce("") { $0 + String($1) }
     }
 }
+
+var lastPendingWorkItems: [String: DispatchWorkItem] = [:]
+
+func debounce(interval: TimeInterval, key: String, queue: DispatchQueue = .main, action: @escaping (() -> Void)) -> () -> Void {
+    var lastFireTime = DispatchTime.now()
+
+    return {
+        lastPendingWorkItems.first { $0.key == key }?.value.cancel()
+
+        lastPendingWorkItems[key] = DispatchWorkItem {
+            let elapsed = DispatchTime.now().uptimeNanoseconds - lastFireTime.uptimeNanoseconds
+            if elapsed >= UInt64(interval * 1_000_000) {
+                action()
+                lastFireTime = DispatchTime.now()
+            }
+        }
+
+        queue.asyncAfter(deadline: .now() + interval, execute: lastPendingWorkItems[key]!)
+    }
+}