swift: Avoid a memcpy delivering message envelopes

And consistently use our Data.init(consuming:) for this pattern.

Author: jrose-signal

swift/Sources/LibSignalClient/ChatListener.swift

@@ -97,15 +97,14 @@ internal class ChatListenerBridge {
     /// or the ChatListenerBridge object used to construct it (`self`) will be leaked.
     func makeListenerStruct() -> SignalFfiChatListenerStruct {
         let receivedIncomingMessage: SignalReceivedIncomingMessage = { rawCtx, envelope, timestamp, ackHandle in
-            defer { signal_free_buffer(envelope.base, envelope.length) }
             let bridge = Unmanaged<ChatListenerBridge>.fromOpaque(rawCtx!).takeUnretainedValue()
 
+            let envelopeData = Data(consuming: envelope)
             let ackHandleOwner = AckHandleOwner(owned: NonNull(ackHandle)!)
             guard let chatConnection = bridge.chatConnection else {
                 return
             }
 
-            let envelopeData = Data(bytes: envelope.base, count: envelope.length)
             bridge.chatListener.chatConnection(
                 chatConnection,
                 didReceiveIncomingMessage: envelopeData,

swift/Sources/LibSignalClient/ChatServiceTypes.swift

@@ -191,13 +191,7 @@ public struct ChatResponse: Equatable, Sendable {
         )
 
         // Avoid copying the body when possible!
-        self.body = Data(
-            bytesNoCopy: rawResponse.body.base,
-            count: rawResponse.body.length,
-            deallocator: .custom { base, length in
-                signal_free_buffer(base, length)
-            }
-        )
+        self.body = Data(consuming: rawResponse.body)
         // Clear it out so it doesn't get freed eagerly.
         rawResponse.body = .init()
 

swift/Sources/LibSignalClient/Utils.swift

@@ -79,13 +79,7 @@ internal func invokeFnReturningOptionalArray(
     return if output.base == nil {
         nil
     } else {
-        Data(
-            bytesNoCopy: output.base,
-            count: output.length,
-            deallocator: .custom { base, length in
-                signal_free_buffer(base, length)
-            }
-        )
+        Data(consuming: output)
     }
 }