commit 97fe2b28f75dca3896d7c35d61858c0b21db1f8f
parent a90b2e5154cc7fd317fe32ddc80873c3dd85c116
Author: Marc Stibane <marc@taler.net>
Date: Fri, 14 Aug 2026 08:28:39 +0200
AI: completions semaphore handling
Diffstat:
1 file changed, 93 insertions(+), 32 deletions(-)
diff --git a/TalerWallet1/Backend/WalletCore.swift b/TalerWallet1/Backend/WalletCore.swift
@@ -71,6 +71,12 @@ class WalletCore: QuickjsMessageHandler {
let payload: AnyCodable?
}
+ /// the bare envelope, which still decodes when the full `ResponseOrNotification` doesn't
+ private struct ResponseHeader: Decodable {
+ let type: String
+ let id: UInt?
+ }
+
struct Payload: Decodable {
let type: String
let id: String?
@@ -101,18 +107,43 @@ class WalletCore: QuickjsMessageHandler {
}
// MARK: - completionHandler functions
extension WalletCore {
+ /// `requestsMade` and `completions` are touched both from the request queue and from
+ /// wallet-core's message handler, thus every access must be guarded by the semaphore.
+ private func reserveRequestId() -> UInt {
+ semaphore.wait()
+ defer { semaphore.signal() }
+ let requestId = requestsMade
+ requestsMade += 1
+ return requestId
+ }
+
+ private func setCompletion(_ requestId: UInt, _ sendTime: Date,
+ _ completion: @escaping (UInt, Date, String?, Data?, TalerErrorDetail?) -> Void) {
+ semaphore.wait()
+ defer { semaphore.signal() }
+ completions[requestId] = (sendTime, completion)
+ }
+
+ /// Take the completion out of the list, so that it can never be called twice.
+ /// Whoever gets it must call it - on every path, including all error paths.
+ private func takeCompletion(_ requestId: UInt)
+ -> (Date, (UInt, Date, String?, Data?, TalerErrorDetail?) -> Void)? {
+ semaphore.wait()
+ defer { semaphore.signal() }
+ return completions.removeValue(forKey: requestId)
+ }
+
private func handleError(_ decoded: ResponseOrNotification, _ message: String?) throws {
guard let requestId = decoded.id else {
logger.error("didn't find requestId in error response")
// TODO: show error alert
throw WalletBackendError.deserializationError
}
- guard let (timeSent, completion) = completions[requestId] else {
+ guard let (timeSent, completion) = takeCompletion(requestId) else {
logger.error("requestId \(requestId, privacy: .public) not in list")
// TODO: show error alert
throw WalletBackendError.deserializationError
}
- completions[requestId] = nil
if let walletError = decoded.error { // wallet-core sent an error message
do {
let jsonData = try JSONEncoder().encode(walletError)
@@ -136,14 +167,14 @@ extension WalletCore {
symLog.log(decoded) // TODO: .error
throw WalletBackendError.deserializationError
}
- guard let (timeSent, completion) = completions[requestId] else {
+ guard let (timeSent, completion) = takeCompletion(requestId) else {
logger.error("requestId \(requestId, privacy: .public) not in list")
throw WalletBackendError.deserializationError
}
- completions[requestId] = nil
- guard let result = decoded.result else {
+ guard let result = decoded.result else { // don't throw - we own the completion now
logger.error("requestId \(requestId, privacy: .public) got no result")
- throw WalletBackendError.deserializationError
+ completion(requestId, timeSent, message, nil, WalletCore.parseResponseError())
+ return
}
do {
let jsonData = try JSONEncoder().encode(result)
@@ -421,7 +452,15 @@ extension WalletCore {
}
}
- @MainActor func handleLog(message: String) {
+ /// wallet-core logs from its own thread, thus hop to the main actor before the console
+ func handleLog(message: String) {
+ guard isLogging else { return } // don't flood the main queue when nobody looks
+ DispatchQueue.main.async { [self] in
+ handleLogM(message: message)
+ }
+ }
+
+ @MainActor private func handleLogM(message: String) {
if #available (iOS 16.0, *) {
if isLogging {
let consoleManager = LCManager.shared
@@ -447,29 +486,53 @@ extension WalletCore {
consoleManager.print("- - -")
}
+ /// A message we could not decode may still be the answer to a pending request.
+ /// Fail that request, otherwise it would wait for an answer which never comes.
+ private func failPendingRequest(_ messageData: Data, _ message: String) {
+ guard let header = try? JSONDecoder().decode(ResponseHeader.self, from: messageData),
+ header.type == "response" || header.type == "error",
+ let requestId = header.id,
+ let (timeSent, completion) = takeCompletion(requestId)
+ else { return }
+ logger.error("undecodable \(header.type, privacy: .public) for request \(requestId, privacy: .public)")
+ completion(requestId, timeSent, message, nil, WalletCore.parseFailureError())
+ }
+
+ /// wallet-core calls this from its own thread, thus hop to the main actor
+ func handleMessage(message: String) {
+ DispatchQueue.main.async { [self] in
+ handleMessageM(message: message)
+ }
+ }
+
/// here not only responses, but also notifications from wallet-core will be received
- @MainActor func handleMessage(message: String) {
+ @MainActor private func handleMessageM(message: String) {
do {
guard let messageData = message.data(using: .utf8) else {
throw WalletBackendError.deserializationError
}
- let decoded = try JSONDecoder().decode(ResponseOrNotification.self, from: messageData)
- switch decoded.type {
- case "error":
- symLog.log("\"id\":\(decoded.id ?? 0) \(message)")
- try handleError(decoded, message)
- case "response":
-// symLog.log(message)
- try handleResponse(decoded, message)
- case "notification":
-// symLog.log(message)
- try handleNotification(decoded.payload, message)
- case "tunnelHttp": // TODO: Handle tunnelHttp
- symLog.log("Can't handle tunnelHttp: \(message)") // TODO: .error
- throw WalletBackendError.deserializationError
- default:
- symLog.log("Unknown response type: \(message)") // TODO: .error
- throw WalletBackendError.deserializationError
+ do {
+ let decoded = try JSONDecoder().decode(ResponseOrNotification.self, from: messageData)
+ switch decoded.type {
+ case "error":
+ symLog.log("\"id\":\(decoded.id ?? 0) \(message)")
+ try handleError(decoded, message)
+ case "response":
+// symLog.log(message)
+ try handleResponse(decoded, message)
+ case "notification":
+// symLog.log(message)
+ try handleNotification(decoded.payload, message)
+ case "tunnelHttp": // TODO: Handle tunnelHttp
+ symLog.log("Can't handle tunnelHttp: \(message)") // TODO: .error
+ throw WalletBackendError.deserializationError
+ default:
+ symLog.log("Unknown response type: \(message)") // TODO: .error
+ throw WalletBackendError.deserializationError
+ }
+ } catch { // e.g. a TalerErrorDetail from a remote server which doesn't decode
+ failPendingRequest(messageData, message) // never leave a request hanging
+ throw error
}
} catch DecodingError.dataCorrupted(let context) {
logger.error("\(context.debugDescription)")
@@ -492,17 +555,13 @@ extension WalletCore {
private func encodeAndSend(_ request: WalletBackendRequest, completionHandler: @escaping (UInt, Date, String?, Data?, TalerErrorDetail?) -> Void) {
// Encode the request and send it to the backend.
queue.async {
- self.semaphore.wait() // guard access to requestsMade
- let requestId = self.requestsMade
+ let requestId = self.reserveRequestId()
let sendTime = Date.now
do {
let full = FullRequest(operation: request.operation, id: requestId, args: request.args)
// symLog.log(full)
let encoded = try JSONEncoder().encode(full)
guard let jsonString = String(data: encoded, encoding: .utf8) else { throw WalletBackendError.serializationError }
- self.completions[requestId] = (sendTime, completionHandler)
- self.requestsMade += 1
- self.semaphore.signal() // free requestsMade
let args = try JSONEncoder().encode(request.args)
if let jsonArgs = String(data: args, encoding: .utf8) {
if request.operation == "getTransactionsV2" {
@@ -515,10 +574,12 @@ extension WalletCore {
} else { // should NEVER happen since the whole request was already successfully encoded and stringified
self.logger.log("🔴\"id\":\(requestId, privacy: .public) \(request.operation, privacy: .public) 🔴 Error: jsonArgs")
}
+ // register only after everything which can throw did succeed, but before
+ // sending - the answer may arrive before sendMessage() even returns
+ self.setCompletion(requestId, sendTime, completionHandler)
self.quickjs.sendMessage(message: jsonString)
// self.symLog.log(jsonString)
- } catch { // call completion
- self.semaphore.signal() // free requestsMade
+ } catch { // call completion - nothing was registered, thus nobody else will
self.logger.error("\(error.localizedDescription)")
// self.symLog.log(error)
completionHandler(requestId, sendTime, nil, nil, WalletCore.serializeRequestError());
