chrome/browser/ui/webui/mojo_web_ui_controller.h

// 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.

#ifndef CHROME_BROWSER_UI_WEBUI_MOJO_WEB_UI_CONTROLLER_H_
#define CHROME_BROWSER_UI_WEBUI_MOJO_WEB_UI_CONTROLLER_H_

#include <memory>
#include <string>

#include "base/macros.h"
#include "base/memory/weak_ptr.h"
#include "chrome/browser/ui/webui/mojo_web_ui_handler.h"
#include "content/public/browser/render_frame_host.h"
#include "content/public/browser/render_view_host.h"
#include "content/public/browser/web_contents.h"
#include "content/public/browser/web_contents_observer.h"
#include "content/public/browser/web_ui_controller.h"
#include "mojo/public/cpp/system/core.h"
#include "services/service_manager/public/cpp/binder_registry.h"

class MojoWebUIControllerBase : public content::WebUIController {
 public:
  explicit MojoWebUIControllerBase(content::WebUI* contents);
  ~MojoWebUIControllerBase() override;

  // WebUIController overrides:
  void RenderFrameCreated(content::RenderFrameHost* render_frame_host) override;

 private:
  DISALLOW_COPY_AND_ASSIGN(MojoWebUIControllerBase);
};

// MojoWebUIController is intended for web ui pages that use mojo. It is
// expected that subclasses will do two things:
// . In the constructor invoke AddMojoResourcePath() to register the bindings
//   files, eg:
//     AddMojoResourcePath("chrome/browser/ui/webui/omnibox/omnibox.mojom",
//                         IDR_OMNIBOX_MOJO_JS);
// . Override BindUIHandler() to create and bind the implementation of the
//   bindings.
template <typename Interface>
class MojoWebUIController : public MojoWebUIControllerBase,
                            public content::WebContentsObserver {
 public:
  explicit MojoWebUIController(content::WebUI* contents)
      : MojoWebUIControllerBase(contents),
        content::WebContentsObserver(contents->GetWebContents()),
        weak_factory_(this) {
    registry_.AddInterface<Interface>(base::Bind(
        &MojoWebUIController::BindUIHandler, base::Unretained(this)));
  }
  ~MojoWebUIController() override {}

  // content::WebContentsObserver implementation.
  void OnInterfaceRequestFromFrame(
      content::RenderFrameHost* render_frame_host,
      const std::string& interface_name,
      mojo::ScopedMessagePipeHandle* interface_pipe) override {
    // Right now, this is expected to be called only for main frames.
    DCHECK(!render_frame_host->GetParent());
    registry_.TryBindInterface(interface_name, interface_pipe);
  }

 protected:
  // Invoked to create the specific bindings implementation.
  virtual void BindUIHandler(mojo::InterfaceRequest<Interface> request) = 0;

 private:
  service_manager::BinderRegistry registry_;

  base::WeakPtrFactory<MojoWebUIController> weak_factory_;

  DISALLOW_COPY_AND_ASSIGN(MojoWebUIController);
};

#endif  // CHROME_BROWSER_UI_WEBUI_MOJO_WEB_UI_CONTROLLER_H_