[Presentation API] (4th)(1-UA blink side) Add WebPresentationConnection and WebPresentationConnecti…

content/renderer/presentation/presentation_connection_proxy.cc

+// Copyright 2017 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 "content/renderer/presentation/presentation_connection_proxy.h"
+
+#include "base/logging.h"
+#include "content/renderer/presentation/presentation_dispatcher.h"
+#include "third_party/WebKit/public/platform/WebString.h"
+#include "third_party/WebKit/public/platform/modules/presentation/WebPresentationConnection.h"
+#include "third_party/WebKit/public/platform/modules/presentation/WebPresentationController.h"
+#include "third_party/WebKit/public/platform/modules/presentation/WebPresentationSessionInfo.h"
+
+namespace content {
+
+PresentationConnectionProxy::PresentationConnectionProxy(
+    blink::WebPresentationConnection* connection)
+    : binding_(this),
+      target_connection_(nullptr),
+      source_connection_(connection) {
+  DCHECK(source_connection_);
+}
+
+PresentationConnectionProxy::~PresentationConnectionProxy() = default;
+
+void PresentationConnectionProxy::SendConnectionMessage(
+    blink::mojom::ConnectionMessagePtr session_message,
+    const OnMessageCallback& callback) const {
+  DCHECK(target_connection_);

[mark a. foltz, 2017/01/23 20:18:41]

It seems like the following three things have to be true for this to succeed:
(1) Source connection is in connected state.
(2) Target connection is in connected state.
(3) Target connection is set (BindTargetConnection has been called).

How do you check (1) and (2)?

[zhaobin, 2017/01/24 01:23:23]

For (1), we will call into PresentationConnectionProxy::SendConnectionMessage()
only if Blink connection (source_connection_) is in 'connected' state because
PresentationConnection::send() checks Blink connection state.

For (2), in 5th patch, we are going to remove 'connected' state transition in
PSImpl so the only place changing 'connecting' to 'connected' is
ReceiverConnectionProxy::BindTargetConnection.

If ReceiverConnectionProxy::BindTargetConnection() has been called before
sending message:

target_connection_ = std::move(connection); // set receiver proxy's
target_connection_ (3)
target_connection_->DidChangeState(blink::mojom::PresentationConnectionState::CONNECTED);
// controller connection changes to 'connected'
DidChangeState(blink::mojom::PresentationConnectionState::CONNECTED); //
receiver connection changes to 'connected'

sending message from receiver -> controller: mojo call
target_connection_->OnMessage() will be queued after
target_connection_->DidChangeState(CONNECTED)
sending message from controller -> receiver: mojo call 
target_connection_->OnMessage() will be sent after local call
DidChangeState(CONNECTED)

For (3), make sure ReceiverConnectionProxy::Bind() and
ReceiverConnectionProxy::BindTargetConnection() are called before sending
messages.
       

+  target_connection_->OnMessage(std::move(session_message), callback);
+}
+
+void PresentationConnectionProxy::OnMessage(
+    blink::mojom::ConnectionMessagePtr message,
+    const OnMessageCallback& callback) {
+  DCHECK(!callback.is_null());
+
+  switch (message->type) {
+    case blink::mojom::PresentationMessageType::TEXT: {
+      DCHECK(message->message);
+      source_connection_->didReceiveTextMessage(
+          blink::WebString::fromUTF8(message->message.value()));
+      break;
+    }
+    case blink::mojom::PresentationMessageType::BINARY: {
+      DCHECK(message->data);
+      source_connection_->didReceiveBinaryMessage(&(message->data->front()),
+                                                  message->data->size());
+      break;
+    }
+    default: {
+      callback.Run(false);
+      NOTREACHED();
+      break;
+    }
+  }
+
+  callback.Run(true);
+}
+
+void PresentationConnectionProxy::DidChangeState(
+    blink::mojom::PresentationConnectionState state) {
+  if (state == blink::mojom::PresentationConnectionState::CONNECTED) {
+    source_connection_->didChangeState(
+        blink::WebPresentationConnectionState::Connected);
+  } else {
+    // |DidChangeState| should only handle state transition from connecting ->

[mark a. foltz, 2017/01/23 20:18:41]

Long term, I'd rather have one code path to handle state transitions - this is
part of a larger conversation about where state changes should be managed w.r.t.
connection lifetime.  

[zhaobin, 2017/01/24 01:23:23]

crbug.com/588874 tracks this. Added a TODO. Currently, close/terminate state
transition is sent by MR extension (cast_provider and cloud_provider). Connected
state transition is sent by PSImpl (by PresentationConnectionProxy in 5th
patch). We can remove this state change if we find a place in MR extension (cast
provider and cloud provider) where we can signal connected state properly.

+    // connected. PresentationService and MRP handles other state transitions.
+    NOTREACHED();
+  }
+}
+
+ControllerConnectionProxy::ControllerConnectionProxy(
+    blink::WebPresentationConnection* connection)
+    : PresentationConnectionProxy(connection) {}
+
+ControllerConnectionProxy::~ControllerConnectionProxy() {}
+
+blink::mojom::PresentationConnectionPtr ControllerConnectionProxy::Bind() {
+  return binding_.CreateInterfacePtrAndBind();
+}
+
+blink::mojom::PresentationConnectionRequest
+ControllerConnectionProxy::MakeRemoteRequest() {
+  DCHECK(!target_connection_)
+      << "target_connection_ should only be bound once.";
+  return mojo::MakeRequest(&target_connection_);
+}
+
+ReceiverConnectionProxy::ReceiverConnectionProxy(
+    blink::WebPresentationConnection* connection)
+    : PresentationConnectionProxy(connection) {}
+
+ReceiverConnectionProxy::~ReceiverConnectionProxy() {}
+
+void ReceiverConnectionProxy::Bind(
+    blink::mojom::PresentationConnectionRequest target_connection_request) {
+  binding_.Bind(std::move(target_connection_request));
+}
+
+void ReceiverConnectionProxy::BindTargetConnection(
+    blink::mojom::PresentationConnectionPtr connection) {
+  DCHECK(!target_connection_);
+  target_connection_ = std::move(connection);
+  target_connection_->DidChangeState(
+      blink::mojom::PresentationConnectionState::CONNECTED);
+
+  DidChangeState(blink::mojom::PresentationConnectionState::CONNECTED);
+}
+
+}  // namespace content