GRPC Stream implementation of HeliumStream

blimp/net/grpc_connection.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "blimp/net/grpc_connection.h"
+
+#include "blimp/common/proto/blimp_message.pb.h"
+
+#include "base/callback.h"
+#include "base/callback_helpers.h"
+#include "base/macros.h"
+#include "base/memory/ptr_util.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "blimp/common/logging.h"
+#include "blimp/net/grpc_stream.h"
+#include "content/public/browser/browser_thread.h"
+#include "net/base/net_errors.h"
+#include "blimp/net/connection_error_observer.h"
+
+namespace blimp {
+
+// NOTE: This entire class/file is going away soon.
+// This set of classes is a thin wrapper around the new HeliumStream-like
+// GrpcStream.
+
+// Forwards a |BlimpMessage| from the client to the Engine via gRPC after
+// converting it to a |HeliumWrapper| first.
+class GrpcOutgoingForwarder : public BlimpMessageProcessor {
+ public:
+  GrpcOutgoingForwarder(GrpcStream* stream,
+                        ConnectionErrorObserver* error_observer)
+      : stream_(stream) {}
+  void ProcessMessage(std::unique_ptr<BlimpMessage> message,
+                      const net::CompletionCallback& callback) override;
+
+ private:
+  GrpcStream* stream_;
+};
+
+void GrpcOutgoingForwarder::ProcessMessage(
+    std::unique_ptr<BlimpMessage> message,
+    const net::CompletionCallback& callback) {
+  DVLOG(3) << "Sending message: " << *message
+           << "; type = " << message->message_id();
+  // DCHECK(message->has_message_id());
+  if (stream_ != nullptr) {
+    auto helium_message = base::MakeUnique<HeliumWrapper>();
+
+    if (message->SerializeToString(
+            helium_message->mutable_serialized_helium_message())) {
+      stream_->SendMessage(std::move(helium_message), callback);
+    } else {
+      LOG(FATAL) << "Unable to serialize message " << *message;
+    }
+  }
+};
+
+// Callback for the gRPC layer that has a new |HeliumWrapper| message to forward
+// to the client's 'incoming message processor' that accepts |BlimpMessage|.
+class GrpcIncomingForwarder {
+ public:
+  GrpcIncomingForwarder(GrpcStream* stream,
+                        ConnectionErrorObserver* error_observer)
+      : stream_(stream),
+        error_observer_(error_observer),
+        incoming_msg_processor_(nullptr),
+        incoming_forwarder_(this) {}
+
+  void set_incoming_message_processor(BlimpMessageProcessor* processor) {
+    auto is_receive_message_setup = (incoming_msg_processor_ != nullptr);
+    incoming_msg_processor_ = processor;
+
+    if (!is_receive_message_setup) {
+      TriggerReceiveMessage();
+    }
+  }
+
+ private:
+  void TriggerReceiveMessage();
+
+  void ReceiveMessage();
+
+  void OnMessageReceived(std::unique_ptr<HeliumWrapper> helium_message,
+                         int result);
+
+  void ProcessResult(int result);
+
+  GrpcStream* stream_;
+  ConnectionErrorObserver* error_observer_;
+  BlimpMessageProcessor* incoming_msg_processor_;
+  base::WeakPtrFactory<GrpcIncomingForwarder> incoming_forwarder_;
+};
+
+void GrpcIncomingForwarder::ProcessResult(int result) {
+  // No-op.
+}
+
+void GrpcIncomingForwarder::TriggerReceiveMessage() {
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE, base::Bind(&GrpcIncomingForwarder::ReceiveMessage,
+                            incoming_forwarder_.GetWeakPtr()));
+}
+
+void GrpcIncomingForwarder::ReceiveMessage() {
+  if (stream_ != nullptr) {
+    stream_->ReceiveMessage(
+        base::Bind(&GrpcIncomingForwarder::OnMessageReceived,
+                   incoming_forwarder_.GetWeakPtr()));
+  }
+}
+
+void GrpcIncomingForwarder::OnMessageReceived(
+    std::unique_ptr<HeliumWrapper> helium_message,
+    int result) {
+  if (result != grpc::OK) {
+    DVLOG(3) << "Received message with error " << result;
+    error_observer_->OnConnectionError(result);
+    return;
+  }
+
+  DVLOG(3) << "Processing message : " << helium_message->GetTypeName();
+  auto blimp_message = base::MakeUnique<BlimpMessage>();
+
+  if (blimp_message->ParseFromString(
+          helium_message->serialized_helium_message())) {
+    if (incoming_msg_processor_ != nullptr) {
+      DVLOG(3) << "Parsed BlimpMessage: " << *blimp_message;
+      incoming_msg_processor_->ProcessMessage(
+          std::move(blimp_message),
+          base::Bind(&GrpcIncomingForwarder::ProcessResult,
+                     incoming_forwarder_.GetWeakPtr()));
+      TriggerReceiveMessage();
+    }
+  } else {
+    LOG(FATAL) << "Unable to deserialize message.";
+  }
+}
+
+// We rely on the gRPC and our //net code to agree on the 'success' code alone.
+// Again, this is interim while we use the current //net as well as gRPC but
+// will go away once we fully move to gRPC alone with strongly-typed results.
+static_assert(static_cast<int>(grpc::OK) == static_cast<int>(net::OK),
+              "Mismatch in error code definitions.");
+
+GrpcConnection::GrpcConnection(std::unique_ptr<GrpcStream> stream)
+    : stream_(std::move(stream)),
+      outgoing_forwarder_(
+          base::MakeUnique<GrpcOutgoingForwarder>(stream_.get(), this)),
+      incoming_forwarder_(
+          base::MakeUnique<GrpcIncomingForwarder>(stream_.get(), this)) {}
+
+BlimpMessageProcessor* GrpcConnection::GetOutgoingMessageProcessor() {
+  return outgoing_forwarder_.get();
+}
+
+void GrpcConnection::SetIncomingMessageProcessor(
+    BlimpMessageProcessor* processor) {
+  DVLOG(3) << "Setting incoming message processor " << processor;
+  incoming_forwarder_->set_incoming_message_processor(processor);
+}
+
+GrpcConnection::~GrpcConnection() {
+  DVLOG(1) << "Ending connection.";
+}
+
+}  // namespace blimp