[async-await] Code generation for "simple, but safe" wrapper client calls. (#1261)

This PR adds codegen support for the "simple, but safe wrappers" that were part of the proposal for async/await support, added in #1231.

Codegen has also been re-run for the example Echo service.

Author: simonjbeaumont

Sources/Examples/Echo/Model/echo.grpc.swift

@@ -248,6 +248,75 @@ extension Echo_EchoAsyncClientProtocol {
   }
 }
 
+@available(macOS 12, iOS 15, tvOS 15, watchOS 8, *)
+extension Echo_EchoAsyncClientProtocol {
+  public func get(
+    _ request: Echo_EchoRequest,
+    callOptions: CallOptions? = nil
+  ) async throws -> Echo_EchoResponse {
+    return try await self.performAsyncUnaryCall(
+      path: "/echo.Echo/Get",
+      request: request,
+      callOptions: callOptions ?? self.defaultCallOptions
+    )
+  }
+
+  public func expand(
+    _ request: Echo_EchoRequest,
+    callOptions: CallOptions? = nil
+  ) -> GRPCAsyncResponseStream<Echo_EchoResponse> {
+    return self.performAsyncServerStreamingCall(
+      path: "/echo.Echo/Expand",
+      request: request,
+      callOptions: callOptions ?? self.defaultCallOptions
+    )
+  }
+
+  public func collect<RequestStream>(
+    _ requests: RequestStream,
+    callOptions: CallOptions? = nil
+  ) async throws -> Echo_EchoResponse where RequestStream: Sequence, RequestStream.Element == Echo_EchoRequest {
+    return try await self.performAsyncClientStreamingCall(
+      path: "/echo.Echo/Collect",
+      requests: requests,
+      callOptions: callOptions ?? self.defaultCallOptions
+    )
+  }
+
+  public func collect<RequestStream>(
+    _ requests: RequestStream,
+    callOptions: CallOptions? = nil
+  ) async throws -> Echo_EchoResponse where RequestStream: AsyncSequence, RequestStream.Element == Echo_EchoRequest {
+    return try await self.performAsyncClientStreamingCall(
+      path: "/echo.Echo/Collect",
+      requests: requests,
+      callOptions: callOptions ?? self.defaultCallOptions
+    )
+  }
+
+  public func update<RequestStream>(
+    _ requests: RequestStream,
+    callOptions: CallOptions? = nil
+  ) -> GRPCAsyncResponseStream<Echo_EchoResponse> where RequestStream: Sequence, RequestStream.Element == Echo_EchoRequest {
+    return self.performAsyncBidirectionalStreamingCall(
+      path: "/echo.Echo/Update",
+      requests: requests,
+      callOptions: callOptions ?? self.defaultCallOptions
+    )
+  }
+
+  public func update<RequestStream>(
+    _ requests: RequestStream,
+    callOptions: CallOptions? = nil
+  ) -> GRPCAsyncResponseStream<Echo_EchoResponse> where RequestStream: AsyncSequence, RequestStream.Element == Echo_EchoRequest {
+    return self.performAsyncBidirectionalStreamingCall(
+      path: "/echo.Echo/Update",
+      requests: requests,
+      callOptions: callOptions ?? self.defaultCallOptions
+    )
+  }
+}
+
 @available(macOS 12, iOS 15, tvOS 15, watchOS 8, *)
 public struct Echo_EchoAsyncClient: Echo_EchoAsyncClientProtocol {
   public var channel: GRPCChannel

Sources/GRPC/AsyncAwaitSupport/GRPCChannel+AsyncAwaitSupport.swift

@@ -26,7 +26,7 @@ extension GRPCChannel {
   ///   - request: The request to send.
   ///   - callOptions: Options for the RPC.
   ///   - interceptors: A list of interceptors to intercept the request and response stream with.
-  public func makeAsyncUnaryCall<Request: Message, Response: Message>(
+  internal func makeAsyncUnaryCall<Request: Message, Response: Message>(
     path: String,
     request: Request,
     callOptions: CallOptions,
@@ -50,7 +50,7 @@ extension GRPCChannel {
   ///   - request: The request to send.
   ///   - callOptions: Options for the RPC.
   ///   - interceptors: A list of interceptors to intercept the request and response stream with.
-  public func makeAsyncUnaryCall<Request: GRPCPayload, Response: GRPCPayload>(
+  internal func makeAsyncUnaryCall<Request: GRPCPayload, Response: GRPCPayload>(
     path: String,
     request: Request,
     callOptions: CallOptions,
@@ -73,7 +73,7 @@ extension GRPCChannel {
   ///   - path: Path of the RPC, e.g. "/echo.Echo/Get"
   ///   - callOptions: Options for the RPC.
   ///   - interceptors: A list of interceptors to intercept the request and response stream with.
-  public func makeAsyncClientStreamingCall<Request: Message, Response: Message>(
+  internal func makeAsyncClientStreamingCall<Request: Message, Response: Message>(
     path: String,
     callOptions: CallOptions,
     interceptors: [ClientInterceptor<Request, Response>] = []
@@ -94,7 +94,7 @@ extension GRPCChannel {
   ///   - path: Path of the RPC, e.g. "/echo.Echo/Get"
   ///   - callOptions: Options for the RPC.
   ///   - interceptors: A list of interceptors to intercept the request and response stream with.
-  public func makeAsyncClientStreamingCall<Request: GRPCPayload, Response: GRPCPayload>(
+  internal func makeAsyncClientStreamingCall<Request: GRPCPayload, Response: GRPCPayload>(
     path: String,
     callOptions: CallOptions,
     interceptors: [ClientInterceptor<Request, Response>] = []
@@ -116,7 +116,7 @@ extension GRPCChannel {
   ///   - request: The request to send.
   ///   - callOptions: Options for the RPC.
   ///   - interceptors: A list of interceptors to intercept the request and response stream with.
-  public func makeAsyncServerStreamingCall<Request: Message, Response: Message>(
+  internal func makeAsyncServerStreamingCall<Request: Message, Response: Message>(
     path: String,
     request: Request,
     callOptions: CallOptions,
@@ -140,7 +140,7 @@ extension GRPCChannel {
   ///   - request: The request to send.
   ///   - callOptions: Options for the RPC.
   ///   - interceptors: A list of interceptors to intercept the request and response stream with.
-  public func makeAsyncServerStreamingCall<Request: GRPCPayload, Response: GRPCPayload>(
+  internal func makeAsyncServerStreamingCall<Request: GRPCPayload, Response: GRPCPayload>(
     path: String,
     request: Request,
     callOptions: CallOptions,
@@ -163,7 +163,7 @@ extension GRPCChannel {
   ///   - path: Path of the RPC, e.g. "/echo.Echo/Get"
   ///   - callOptions: Options for the RPC.
   ///   - interceptors: A list of interceptors to intercept the request and response stream with.
-  public func makeAsyncBidirectionalStreamingCall<Request: Message, Response: Message>(
+  internal func makeAsyncBidirectionalStreamingCall<Request: Message, Response: Message>(
     path: String,
     callOptions: CallOptions,
     interceptors: [ClientInterceptor<Request, Response>] = []
@@ -184,7 +184,7 @@ extension GRPCChannel {
   ///   - path: Path of the RPC, e.g. "/echo.Echo/Get"
   ///   - callOptions: Options for the RPC.
   ///   - interceptors: A list of interceptors to intercept the request and response stream with.
-  public func makeAsyncBidirectionalStreamingCall<Request: GRPCPayload, Response: GRPCPayload>(
+  internal func makeAsyncBidirectionalStreamingCall<Request: GRPCPayload, Response: GRPCPayload>(
     path: String,
     callOptions: CallOptions,
     interceptors: [ClientInterceptor<Request, Response>] = []