Event for pending HTLCs forwardable and swift implementation for processing them

Author: Jasonvdb

ios/Classes/LdkChannelManagerPersister.swift

@@ -139,7 +139,16 @@ class LdkChannelManagerPersister: Persister, ExtendedChannelManagerPersister {
             //Unused on mobile
             return
         case .PendingHTLCsForwardable:
-            //TODO not sure if required.
+            guard let pendingHTLCsForwardable = event.getValueAsPendingHTLCsForwardable() else {
+                return handleEventError(event)
+            }
+                        
+            LdkEventEmitter.shared.send(
+                withEvent: .channel_manager_pending_htlcs_forwardable,
+                body: [
+                    "time_forwardable": pendingHTLCsForwardable.getTime_forwardable(),
+                ]
+            )
             return
         case .SpendableOutputs:
             guard let spendableOutputs = event.getValueAsSpendableOutputs() else {

ios/Ldk.m

@@ -80,6 +80,8 @@ @interface RCT_EXTERN_MODULE(Ldk, NSObject)
                   description:(NSString *)description
                   resolve:(RCTPromiseResolveBlock)resolve
                   reject:(RCTPromiseRejectBlock)reject)
+RCT_EXTERN_METHOD(processPendingHtlcForwards:(RCTPromiseResolveBlock)resolve
+                  reject:(RCTPromiseRejectBlock)reject)
 @end
 
 //MARK: Events

ios/Ldk.swift

@@ -21,6 +21,7 @@ enum EventTypes: String, CaseIterable {
     case channel_manager_payment_path_successful = "channel_manager_payment_path_successful"
     case channel_manager_payment_path_failed = "channel_manager_payment_path_failed"
     case channel_manager_payment_failed = "channel_manager_payment_failed"
+    case channel_manager_pending_htlcs_forwardable = "channel_manager_pending_htlcs_forwardable"
     case channel_manager_spendable_outputs = "channel_manager_spendable_outputs"
     case channel_manager_channel_closed = "channel_manager_channel_closed"
     case channel_manager_discard_funding = "channel_manager_discard_funding"
@@ -66,6 +67,7 @@ enum LdkCallbackResponses: String {
     case invoice_payment_success = "invoice_payment_success"
     case tx_set_confirmed = "tx_set_confirmed"
     case tx_set_unconfirmed = "tx_set_unconfirmed"
+    case process_pending_htlc_forwards_success = "process_pending_htlc_forwards_success"
 }
 
 @objc(Ldk)
@@ -467,6 +469,17 @@ class Ldk: NSObject {
         return handleReject(reject, .invoice_create_failed, nil, "Invoice creation error: \(creationError.rawValue)")
     }
 
+    @objc
+    func processPendingHtlcForwards(_ resolve: @escaping RCTPromiseResolveBlock, reject: @escaping RCTPromiseRejectBlock) {
+        guard let channelManager = channelManager else {
+            return handleReject(reject, .init_channel_manager)
+        }
+        
+        channelManager.process_pending_htlc_forwards()
+        
+        handleResolve(resolve, .process_pending_htlc_forwards_success)
+    }
+    
     //MARK: Fetch methods
     @objc
     func version(_ resolve: @escaping RCTPromiseResolveBlock, reject: @escaping RCTPromiseRejectBlock) {

src/ldk.ts

@@ -310,6 +310,19 @@ class LDK {
 		}
 	}
 
+	/**
+	 * https://docs.rs/lightning/latest/lightning/ln/channelmanager/struct.ChannelManager.html#method.process_pending_htlc_forwards
+	 * @returns {Promise<Err<unknown> | Ok<Ok<string> | Err<string>>>}
+	 */
+	async processPendingHtlcForwards(): Promise<Result<string>> {
+		try {
+			const res = await NativeLDK.processPendingHtlcForwards();
+			return ok(res);
+		} catch (e) {
+			return err(e);
+		}
+	}
+
 	/**
 	 * Pays a bolt11 payment request
 	 * @param paymentRequest

src/lightning-manager.ts

@@ -20,6 +20,7 @@ import {
 	TPersistManagerEvent,
 	TRegisterOutputEvent,
 	TRegisterTxEvent,
+	TChannelManagerPendingHtlcsForwardable,
 } from './utils/types';
 import {
 	dummyRandomSeed,
@@ -105,6 +106,10 @@ class LightningManager {
 			EEventTypes.channel_manager_payment_failed,
 			this.onChannelManagerPaymentFailed.bind(this),
 		);
+		ldk.onEvent(
+			EEventTypes.channel_manager_pending_htlcs_forwardable,
+			this.onChannelManagerPendingHtlcsForwardable.bind(this),
+		);
 		ldk.onEvent(
 			EEventTypes.channel_manager_spendable_outputs,
 			this.onChannelManagerSpendableOutputs.bind(this),
@@ -369,6 +374,12 @@ class LightningManager {
 		console.log(`onChannelManagerPaymentFailed: ${JSON.stringify(res)}`); //TODO
 	}
 
+	private onChannelManagerPendingHtlcsForwardable(
+		res: TChannelManagerPendingHtlcsForwardable,
+	): void {
+		ldk.processPendingHtlcForwards().catch(console.error);
+	}
+
 	private onChannelManagerSpendableOutputs(
 		res: TChannelManagerSpendableOutputs,
 	): void {

src/utils/types.ts

@@ -22,6 +22,7 @@ export enum EEventTypes {
 	channel_manager_payment_path_successful = 'channel_manager_payment_path_successful',
 	channel_manager_payment_path_failed = 'channel_manager_payment_path_failed',
 	channel_manager_payment_failed = 'channel_manager_payment_failed',
+	channel_manager_pending_htlcs_forwardable = 'channel_manager_pending_htlcs_forwardable',
 	channel_manager_spendable_outputs = 'channel_manager_spendable_outputs',
 	channel_manager_channel_closed = 'channel_manager_channel_closed',
 	channel_manager_discard_funding = 'channel_manager_discard_funding',
@@ -89,6 +90,9 @@ export type TChannelManagerPaymentFailed = {
 	payment_id: string;
 	payment_hash: string;
 };
+export type TChannelManagerPendingHtlcsForwardable = {
+	time_forwardable: number;
+};
 export type TChannelManagerSpendableOutputs = {
 	outputs: string[];
 };