1// Copyright (c) 2011 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef CHROME_BROWSER_SESSIONS_SESSION_TAB_HELPER_H_
6#define CHROME_BROWSER_SESSIONS_SESSION_TAB_HELPER_H_
7
8#include "base/basictypes.h"
9#include "components/sessions/session_id.h"
10#include "content/public/browser/web_contents_observer.h"
11#include "content/public/browser/web_contents_user_data.h"
12
13// This class keeps the extension API's windowID up-to-date with the current
14// window of the tab.
15class SessionTabHelper : public content::WebContentsObserver,
16                         public content::WebContentsUserData<SessionTabHelper> {
17 public:
18  virtual ~SessionTabHelper();
19
20  // Returns the identifier used by session restore for this tab.
21  const SessionID& session_id() const { return session_id_; }
22
23  // Identifier of the window the tab is in.
24  void SetWindowID(const SessionID& id);
25  const SessionID& window_id() const { return window_id_; }
26
27  // If the specified WebContents has a SessionTabHelper (probably because it
28  // was used as the contents of a tab), returns a tab id. This value is
29  // immutable for a given tab. It will be unique across Chrome within the
30  // current session, but may be re-used across sessions. Returns -1
31  // for a NULL WebContents or if the WebContents has no SessionTabHelper.
32  static SessionID::id_type IdForTab(const content::WebContents* tab);
33
34  // If the specified WebContents has a SessionTabHelper (probably because it
35  // was used as the contents of a tab), and has ever been attached to a Browser
36  // window, returns Browser::session_id().id() for that Browser. If the tab is
37  // being dragged between Browser windows, returns the old window's id value.
38  // If the WebContents has a SessionTabHelper but has never been attached to a
39  // Browser window, returns an id value that is different from that of any
40  // Browser. Returns -1 for a NULL WebContents or if the WebContents has no
41  // SessionTabHelper.
42  static SessionID::id_type IdForWindowContainingTab(
43      const content::WebContents* tab);
44
45  // content::WebContentsObserver:
46#if defined(ENABLE_EXTENSIONS)
47  virtual void RenderViewCreated(
48      content::RenderViewHost* render_view_host) OVERRIDE;
49#endif
50  virtual void UserAgentOverrideSet(const std::string& user_agent) OVERRIDE;
51
52 private:
53  explicit SessionTabHelper(content::WebContents* contents);
54  friend class content::WebContentsUserData<SessionTabHelper>;
55
56  // Unique identifier of the tab for session restore. This id is only unique
57  // within the current session, and is not guaranteed to be unique across
58  // sessions.
59  const SessionID session_id_;
60
61  // Unique identifier of the window the tab is in.
62  SessionID window_id_;
63
64  DISALLOW_COPY_AND_ASSIGN(SessionTabHelper);
65};
66
67#endif  // CHROME_BROWSER_SESSIONS_SESSION_TAB_HELPER_H_
68