chrome/browser/ui/tabs/hover_tab_selector.cc

   1 // Copyright (c) 2012 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 #include "chrome/browser/ui/tabs/hover_tab_selector.h"
   6
   7 #include "base/bind.h"
   8 #include "base/compiler_specific.h"
   9 #include "base/message_loop/message_loop.h"
  10 #include "chrome/browser/ui/tabs/tab_strip_model.h"
  11
  12 HoverTabSelector::HoverTabSelector(
  13     TabStripModel* tab_strip_model)
  14     : tab_strip_model_(tab_strip_model),
  15       tab_transition_tab_index_(-1),
  16       weak_factory_(this) {
  17   DCHECK(tab_strip_model_);
  18 }
  19
  20 HoverTabSelector::~HoverTabSelector() {
  21 }
  22
  23 void HoverTabSelector::StartTabTransition(int index) {
  24   // If there is a transition underway already, only start a new
  25   // transition (canceling the old one) if the target tab differs.
  26   if (weak_factory_.HasWeakPtrs()) {
  27     if (index == tab_transition_tab_index_)
  28       return;
  29     CancelTabTransition();
  30   }
  31   // Start a new transition if the target isn't active already.
  32   if (index != tab_strip_model_->active_index()) {
  33     // The delay between beginning to hover over a tab and the transition
  34     // to that tab taking place.
  35     const base::TimeDelta kHoverTransitionDelay =
  36         base::TimeDelta::FromMilliseconds(500);
  37     tab_transition_tab_index_ = index;
  38     base::MessageLoop::current()->PostDelayedTask(
  39         FROM_HERE,
  40         base::Bind(&HoverTabSelector::PerformTabTransition,
  41                    weak_factory_.GetWeakPtr()),
  42         kHoverTransitionDelay);
  43   }
  44 }
  45
  46 void HoverTabSelector::CancelTabTransition() {
  47   weak_factory_.InvalidateWeakPtrs();
  48 }
  49
  50 void HoverTabSelector::PerformTabTransition() {
  51   DCHECK(tab_transition_tab_index_ >= 0 &&
  52          tab_transition_tab_index_ < tab_strip_model_->count());
  53   tab_strip_model_->ActivateTabAt(tab_transition_tab_index_, true);
  54 }
  55