// 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.
#ifndef CHROME_BROWSER_UI_TABS_TAB_STRIP_MODEL_OBSERVER_H_
#define CHROME_BROWSER_UI_TABS_TAB_STRIP_MODEL_OBSERVER_H_
class TabStripModel;
namespace content {
class WebContents;
}
namespace ui {
class ListSelectionModel;
}
////////////////////////////////////////////////////////////////////////////////
//
// TabStripModelObserver
//
// Objects implement this interface when they wish to be notified of changes
// to the TabStripModel.
//
// Two major implementers are the TabStrip, which uses notifications sent
// via this interface to update the presentation of the strip, and the Browser
// object, which updates bookkeeping and shows/hides individual WebContentses.
//
// Register your TabStripModelObserver with the TabStripModel using its
// Add/RemoveObserver methods.
//
////////////////////////////////////////////////////////////////////////////////
class TabStripModelObserver {
public:
// Enumeration of the possible values supplied to TabChangedAt.
enum TabChangeType {
// Only the loading state changed.
LOADING_ONLY,
// Only the title changed and page isn't loading.
TITLE_NOT_LOADING,
// Change not characterized by LOADING_ONLY or TITLE_NOT_LOADING.
ALL
};
enum ChangeReason {
// Used to indicate that none of the reasons below are responsible for the
// active tab change.
CHANGE_REASON_NONE = 0,
// The active tab changed because the tab's web contents was replaced.
CHANGE_REASON_REPLACED = 1 << 0,
// The active tab changed due to a user input event.
CHANGE_REASON_USER_GESTURE = 1 << 1,
};
// A new WebContents was inserted into the TabStripModel at the
// specified index. |foreground| is whether or not it was opened in the
// foreground (selected).
virtual void TabInsertedAt(content::WebContents* contents,
int index,
bool foreground);
// The specified WebContents at |index| is being closed (and eventually
// destroyed). |tab_strip_model| is the TabStripModel that contained the tab.
virtual void TabClosingAt(TabStripModel* tab_strip_model,
content::WebContents* contents,
int index);
// The specified WebContents at |index| is being detached, perhaps to
// be inserted in another TabStripModel. The implementer should take whatever
// action is necessary to deal with the WebContents no longer being
// present.
virtual void TabDetachedAt(content::WebContents* contents, int index);
// The active WebContents is about to change from |old_contents|.
// This gives observers a chance to prepare for an impending switch before it
// happens.
virtual void TabDeactivated(content::WebContents* contents);
// Sent when the active tab changes. The previously active tab is identified
// by |old_contents| and the newly active tab by |new_contents|. |index| is
// the index of |new_contents|. If |reason| has CHANGE_REASON_REPLACED set
// then the web contents was replaced (see TabChangedAt). If |reason| has
// CHANGE_REASON_USER_GESTURE set then the web contents was changed due to a
// user input event (e.g. clicking on a tab, keystroke).
// Note: It is possible for the selection to change while the active tab
// remains unchanged. For example, control-click may not change the active tab
// but does change the selection. In this case |ActiveTabChanged| is not sent.
// If you care about any changes to the selection, override
// TabSelectionChanged.
// Note: |old_contents| will be NULL if there was no contents previously
// active.
virtual void ActiveTabChanged(content::WebContents* old_contents,
content::WebContents* new_contents,
int index,
int reason);
// Sent when the selection changes in |tab_strip_model|. More precisely when
// selected tabs, anchor tab or active tab change. |old_model| is a snapshot
// of the selection model before the change. See also ActiveTabChanged for
// details.
virtual void TabSelectionChanged(TabStripModel* tab_strip_model,
const ui::ListSelectionModel& old_model);
// The specified WebContents at |from_index| was moved to |to_index|.
virtual void TabMoved(content::WebContents* contents,
int from_index,
int to_index);
// The specified WebContents at |index| changed in some way. |contents|
// may be an entirely different object and the old value is no longer
// available by the time this message is delivered.
//
// See TabChangeType for a description of |change_type|.
virtual void TabChangedAt(content::WebContents* contents,
int index,
TabChangeType change_type);
// The WebContents was replaced at the specified index. This is invoked
// when instant is enabled and the user navigates by way of instant or when
// prerendering swaps in a prerendered WebContents.
virtual void TabReplacedAt(TabStripModel* tab_strip_model,
content::WebContents* old_contents,
content::WebContents* new_contents,
int index);
// Invoked when the pinned state of a tab changes. See note in
// TabMiniStateChanged as to how this relates to TabMiniStateChanged.
virtual void TabPinnedStateChanged(content::WebContents* contents, int index);
// Invoked if the mini state of a tab changes.
// NOTE: This is sent when the pinned state of a non-app tab changes and is
// sent in addition to TabPinnedStateChanged. UI code typically need not care
// about TabPinnedStateChanged, but instead this.
virtual void TabMiniStateChanged(content::WebContents* contents, int index);
// Invoked when the blocked state of a tab changes.
// NOTE: This is invoked when a tab becomes blocked/unblocked by a tab modal
// window.
virtual void TabBlockedStateChanged(content::WebContents* contents,
int index);
// The TabStripModel now no longer has any tabs. The implementer may
// use this as a trigger to try and close the window containing the
// TabStripModel, for example...
virtual void TabStripEmpty();
// Sent when the tabstrip model is about to be deleted and any reference held
// must be dropped.
virtual void TabStripModelDeleted();
protected:
virtual ~TabStripModelObserver() {}
};
#endif // CHROME_BROWSER_UI_TABS_TAB_STRIP_MODEL_OBSERVER_H_