use a private function to simplify cascading channel failures

Author: MahdiBM

Sources/PostgresNIO/Connection/PostgresConnection.swift

@@ -222,9 +222,7 @@ public final class PostgresConnection: @unchecked Sendable {
             promise: promise
         )
 
-        let writePromise = self.channel.eventLoop.makePromise(of: Void.self)
-        self.channel.write(HandlerTask.extendedQuery(context), promise: writePromise)
-        writePromise.futureResult.cascadeFailure(to: promise)
+        self.write(HandlerTask.extendedQuery(context), cascadingFailureTo: promise)
 
         return promise.futureResult
     }
@@ -241,9 +239,7 @@ public final class PostgresConnection: @unchecked Sendable {
             promise: promise
         )
 
-        let writePromise = self.channel.eventLoop.makePromise(of: Void.self)
-        self.channel.write(HandlerTask.extendedQuery(context), promise: writePromise)
-        writePromise.futureResult.cascadeFailure(to: promise)
+        self.write(HandlerTask.extendedQuery(context), cascadingFailureTo: promise)
 
         return promise.futureResult.map { rowDescription in
             PSQLPreparedStatement(name: name, query: query, connection: self, rowDescription: rowDescription)
@@ -260,9 +256,7 @@ public final class PostgresConnection: @unchecked Sendable {
             logger: logger,
             promise: promise)
 
-        let writePromise = self.channel.eventLoop.makePromise(of: Void.self)
-        self.channel.write(HandlerTask.extendedQuery(context), promise: writePromise)
-        writePromise.futureResult.cascadeFailure(to: promise)
+        self.write(HandlerTask.extendedQuery(context), cascadingFailureTo: promise)
 
         return promise.futureResult
     }
@@ -271,9 +265,7 @@ public final class PostgresConnection: @unchecked Sendable {
         let promise = self.channel.eventLoop.makePromise(of: Void.self)
         let context = CloseCommandContext(target: target, logger: logger, promise: promise)
 
-        let writePromise = self.channel.eventLoop.makePromise(of: Void.self)
-        self.channel.write(HandlerTask.closeCommand(context), promise: writePromise)
-        writePromise.futureResult.cascadeFailure(to: promise)
+        self.write(HandlerTask.closeCommand(context), cascadingFailureTo: promise)
 
         return promise.futureResult
     }
@@ -437,9 +429,7 @@ extension PostgresConnection {
             promise: promise
         )
 
-        let writePromise = self.channel.eventLoop.makePromise(of: Void.self)
-        self.channel.write(HandlerTask.extendedQuery(context), promise: writePromise)
-        writePromise.futureResult.cascadeFailure(to: promise)
+        self.write(HandlerTask.extendedQuery(context), cascadingFailureTo: promise)
 
         do {
             return try await promise.futureResult.map({ $0.asyncSequence() }).get()
@@ -498,9 +488,7 @@ extension PostgresConnection {
             promise: promise
         ))
 
-        let writePromise = self.channel.eventLoop.makePromise(of: Void.self)
-        self.channel.write(task, promise: writePromise)
-        writePromise.futureResult.cascadeFailure(to: promise)
+        self.write(task, cascadingFailureTo: promise)
 
         do {
             return try await promise.futureResult
@@ -537,9 +525,7 @@ extension PostgresConnection {
             promise: promise
         ))
 
-        let writePromise = self.channel.eventLoop.makePromise(of: Void.self)
-        self.channel.write(task, promise: writePromise)
-        writePromise.futureResult.cascadeFailure(to: promise)
+        self.write(task, cascadingFailureTo: promise)
 
         do {
             return try await promise.futureResult
@@ -555,6 +541,12 @@ extension PostgresConnection {
             throw error // rethrow with more metadata
         }
     }
+
+    private func write<T, Value>(_ any: T, cascadingFailureTo promise: EventLoopPromise<Value>) {
+        let writePromise = self.channel.eventLoop.makePromise(of: Void.self)
+        self.channel.write(any, promise: writePromise)
+        writePromise.futureResult.cascadeFailure(to: promise)
+    }
 }
 
 // MARK: EventLoopFuture interface
@@ -738,10 +730,7 @@ extension PostgresConnection {
             closure: notificationHandler
         )
 
-        let task = HandlerTask.startListening(listener)
-        let writePromise = self.channel.eventLoop.makePromise(of: Void.self)
-        self.channel.write(task, promise: writePromise)
-        writePromise.futureResult.cascadeFailure(to: listenContext.promise)
+        self.write(HandlerTask.startListening(listener), cascadingFailureTo: listenContext.promise)
 
         listenContext.future.whenComplete { _ in
             let task = HandlerTask.cancelListening(channel, id)
@@ -788,3 +777,4 @@ extension PostgresConnection {
 #endif
     }
 }
+