Remote Assistance on Chrome OS Part III - NativeMessageHost

chrome/browser/extensions/api/messaging/native_message_port.cc

 // Copyright (c) 2012 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 "chrome/browser/extensions/api/messaging/native_message_port.h"
 
 #include "base/bind.h"
+#include "base/single_thread_task_runner.h"
 #include "chrome/browser/extensions/api/messaging/native_message_process_host.h"
 #include "content/public/browser/browser_thread.h"
 
 namespace extensions {
 
-NativeMessagePort::NativeMessagePort(NativeMessageProcessHost* native_process)
-    : native_process_(native_process) {
+typedef NativeMessageHost::Client Client;

[Sergey Ulanov, 2014/10/01 23:23:59]

Don't need this typedef: Client is used in only one place in this file. It also
makes code less readable.

[kelvinp, 2014/10/02 03:12:16]

Done.

+
+// Handles jumping between the |host_task_runner| and the
+// |message_service_task_runner|.
+// All methods on the host interface should be called on |host_task_runner|.
+// All methods on |weak_port| (that calls into MessageServices) should be called
+// on |message_service_task_runner|.
+class NativeMessagePort::Core : public Client {
+ public:
+  Core(
+      scoped_ptr<NativeMessageHost> host,
+      base::WeakPtr<NativeMessagePort> weak_port,

[Sergey Ulanov, 2014/10/01 23:23:59]

don't need 'weak_' prefix.

[kelvinp, 2014/10/02 03:12:17]

Done.

+      scoped_refptr<base::SingleThreadTaskRunner> message_service_task_runner_);
+  virtual ~Core();
+
+  void OnMessageFromChrome(const std::string& message);
+
+  // NativeMessageHost::Client implementation.
+  virtual void PostMessageFromNativeHost(const std::string& message) OVERRIDE;
+  virtual void CloseChannel(const std::string& error_message) OVERRIDE;
+
+ private:
+  scoped_ptr<NativeMessageHost> host_;
+  base::WeakPtr<NativeMessagePort> weak_port_;

[Sergey Ulanov, 2014/10/01 23:23:58]

port_

[kelvinp, 2014/10/02 03:12:17]

Done.

+
+  scoped_refptr<base::SingleThreadTaskRunner> message_service_task_runner_;
+  scoped_refptr<base::SingleThreadTaskRunner> host_task_runner_;
+};
+
+NativeMessagePort::Core::Core(
+    scoped_ptr<NativeMessageHost> host,
+    base::WeakPtr<NativeMessagePort> weak_port,
+    scoped_refptr<base::SingleThreadTaskRunner> message_service_task_runner)
+    : host_(host.Pass()),
+      weak_port_(weak_port),
+      message_service_task_runner_(message_service_task_runner),
+      host_task_runner_(host_->task_runner()) {
+  DCHECK(message_service_task_runner_->BelongsToCurrentThread());
+  host_task_runner_->PostTask(FROM_HERE,
+                              base::Bind(&NativeMessageHost::set_client,
+                                         base::Unretained(host_.get()),
+                                         base::Unretained(this)));
+}
+
+NativeMessagePort::Core::~Core() {

[Sergey Ulanov, 2014/10/01 23:23:59]

This object must always be destroyed on |host_task_runner_|. Otherwise the host
may call PostMessageFromNativeHost() after it's destroyed. Call DeleteSoon() in
~NativeMessagePort() to delete the core_ and add DCHECK() here. Don't need
DeleteSoon() for host_.

[kelvinp, 2014/10/02 03:12:16]

Done.

+  if (!host_task_runner_->BelongsToCurrentThread()) {
+    host_task_runner_->DeleteSoon(FROM_HERE, host_.release());
+  }
+}
+
+void NativeMessagePort::Core::OnMessageFromChrome(const std::string& message) {
+  DCHECK(message_service_task_runner_->BelongsToCurrentThread());
+  host_task_runner_->PostTask(FROM_HERE,
+                              base::Bind(&NativeMessageHost::OnMessage,
+                                         base::Unretained(host_.get()),
+                                         message));
+}
+
+void NativeMessagePort::Core::PostMessageFromNativeHost(
+    const std::string& message) {
+  DCHECK(host_task_runner_->BelongsToCurrentThread());
+  message_service_task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(
+          &NativeMessagePort::PostMessageFromNativeHost, weak_port_, message));
+}
+
+void NativeMessagePort::Core::CloseChannel(const std::string& error_message) {
+  DCHECK(host_task_runner_->BelongsToCurrentThread());
+  message_service_task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(&NativeMessagePort::CloseChannel, weak_port_, error_message));
+}
+
+NativeMessagePort::NativeMessagePort(
+    base::WeakPtr<MessageService> message_service,
+    int port_id,
+    scoped_ptr<NativeMessageHost> native_message_host)
+    : weak_message_service_(message_service),
+      port_id_(port_id),
+      weak_factory_(this) {
+  core_.reset(new Core(native_message_host.Pass(),
+                       weak_factory_.GetWeakPtr(),
+                       base::MessageLoopProxy::current()));
 }
 
 NativeMessagePort::~NativeMessagePort() {
-  content::BrowserThread::DeleteSoon(
-      content::BrowserThread::IO, FROM_HERE, native_process_);
 }
 
 void NativeMessagePort::DispatchOnMessage(
     const Message& message,
     int target_port_id) {
-  content::BrowserThread::PostTask(
-      content::BrowserThread::IO, FROM_HERE,
-      base::Bind(&NativeMessageProcessHost::Send,
-                 base::Unretained(native_process_), message.data));
+  DCHECK(thread_checker_.CalledOnValidThread());
+  core_->OnMessageFromChrome(message.data);
+}
+
+void NativeMessagePort::PostMessageFromNativeHost(const std::string& message) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  if (weak_message_service_) {
+    weak_message_service_->PostMessage(
+        port_id_, Message(message, false /* user_gesture */));
+  }
+}
+
+void NativeMessagePort::CloseChannel(const std::string& error_message) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  if (weak_message_service_) {
+    weak_message_service_->CloseChannel(port_id_, error_message);
+  }
 }
 
 }  // namespace extensions