Remote Assistance on Chrome OS Part III - NativeMessageHost

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

+// Copyright 2014 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 "extensions/browser/api/messaging/native_message_host.h"
+
+#include <string>
+
+#include "base/command_line.h"
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "extensions/common/constants.h"
+#include "extensions/common/switches.h"
+#include "extensions/common/url_pattern.h"
+#include "ui/gfx/native_widget_types.h"
+#include "url/gurl.h"
+
+namespace extensions {
+
+namespace {
+
+typedef NativeMessageHost::Client Client;

[Sergey Ulanov, 2014/09/27 00:24:10]

Don't need this typedef. EchoHost inherits NativeMessageHost and you use Client
only inside EchoHost.

[kelvinp, 2014/09/29 22:59:40]

Done.

+
+// A simple NativeMesageHost that echoes the received message. It is currently
+// used for testing.
+// TODO(kelvinp): Replace this class once Remote Assistance in process host
+// is implemented.
+class EchoHost : public NativeMessageHost {
+ public:
+  static scoped_ptr<NativeMessageHost> CreateEchoHost() {
+    return scoped_ptr<NativeMessageHost>(new EchoHost());
+  }
+
+  EchoHost() {}
+
+  virtual void set_client(base::WeakPtr<Client> client) OVERRIDE {
+    client_ = client;
+  }
+
+  virtual void Send(const std::string& json) OVERRIDE {
+    client_->PostMessageFromNativeHost(json);
+  };
+
+ private:
+  base::WeakPtr<Client> client_;
+
+  DISALLOW_COPY_AND_ASSIGN(EchoHost);
+};
+
+struct BuiltInHost {
+  const char* const name;
+  const char* const* const allowed_origins;
+  int allowed_origins_count;
+  scoped_ptr<NativeMessageHost>(*create_function)();
+};
+
+// If you modify the list of allowed_origins, don't forget to update
+// remoting/host/it2me/com.google.chrome.remote_assistance.json.jinja2
+// to keep the two lists in sync.
+// TODO(kelvinp): Load the native messaging manifest as a resource file into
+// chrome and fetch the list of allowed_origins from the manifest.
+const char* const kRemotingIt2MeOrigins[] = {
+    "chrome-extension://ljacajndfccfgnfohlgkdphmbnpkjflk/",
+    "chrome-extension://gbchcmhmhahfdphkhkmpfmihenigjmpp/",
+    "chrome-extension://kgngmbheleoaphbjbaiobfdepmghbfah/",
+    "chrome-extension://odkaodonbgfohohmklejpjiejmcipmib/",
+    "chrome-extension://dokpleeekgeeiehdhmdkeimnkmoifgdd/",
+    "chrome-extension://ajoainacpilcemgiakehflpbkbfipojk/",
+    "chrome-extension://hmboipgjngjoiaeicfdifdoeacilalgc/"};
+
+static const BuiltInHost kBuiltInHost[] = {
+    {"com.google.chrome.remote_assistance",
+     kRemotingIt2MeOrigins,
+     arraysize(kRemotingIt2MeOrigins),
+     &EchoHost::CreateEchoHost},
+};
+
+bool MatchesSecurityOrigin(const BuiltInHost& host,
+                           const std::string& extension_id) {
+  GURL origin(std::string(kExtensionScheme) + "://" + extension_id);
+  for (int i = 0; i < host.allowed_origins_count; i++) {
+    URLPattern allowed_origin(URLPattern::SCHEME_ALL);
+    DCHECK_EQ(URLPattern::PARSE_SUCCESS,
+              allowed_origin.Parse(host.allowed_origins[i]));
+    if (allowed_origin.MatchesSecurityOrigin(origin)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+}  // namespace
+
+scoped_ptr<NativeMessageHost> NativeMessageHost::Create(
+    gfx::NativeView native_view,
+    const std::string& source_extension_id,
+    const std::string& native_host_name,
+    bool allow_user_level) {
+  scoped_ptr<NativeMessageHost> not_found;
+
+  if (!CommandLine::ForCurrentProcess()
+           ->HasSwitch(switches::kEnableRemoteAssistance)) {

[Sergey Ulanov, 2014/09/27 00:24:10]

I think it makes more sense to put this in the function that actually creates
the It2Me host. Otherwise it looks confusing here since the flag per se is not
related to native messaging.

Also without this check you can remove |not_found|.

[kelvinp, 2014/09/29 22:59:40]

Done.

+    return not_found.Pass();
+  }
+
+  for (unsigned int i = 0; i < arraysize(kBuiltInHost); i++) {
+    const BuiltInHost& host = kBuiltInHost[i];
+    std::string name(host.name);
+    if (name == native_host_name &&
+        MatchesSecurityOrigin(host, source_extension_id)) {
+      return (*host.create_function)();
+    }
+  }
+
+  return not_found.Pass();
+}
+
+}  // namespace extensions