components/mus/server_view_drawn_tracker.cc

   1 // Copyright 2015 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 "components/mus/server_view_drawn_tracker.h"
   6
   7 #include "components/mus/server_view.h"
   8 #include "components/mus/server_view_drawn_tracker_observer.h"
   9
  10 namespace mus {
  11
  12 ServerViewDrawnTracker::ServerViewDrawnTracker(
  13     ServerView* view,
  14     ServerViewDrawnTrackerObserver* observer)
  15     : view_(view), observer_(observer), drawn_(view->IsDrawn()) {
  16   AddObservers();
  17 }
  18
  19 ServerViewDrawnTracker::~ServerViewDrawnTracker() {
  20   RemoveObservers();
  21 }
  22
  23 void ServerViewDrawnTracker::SetDrawn(ServerView* ancestor, bool drawn) {
  24   if (drawn == drawn_)
  25     return;
  26
  27   drawn_ = drawn;
  28   observer_->OnDrawnStateChanged(ancestor, view_, drawn);
  29 }
  30
  31 void ServerViewDrawnTracker::AddObservers() {
  32   if (!view_)
  33     return;
  34
  35   for (ServerView* v = view_; v; v = v->parent()) {
  36     v->AddObserver(this);
  37     views_.insert(v);
  38   }
  39 }
  40
  41 void ServerViewDrawnTracker::RemoveObservers() {
  42   for (ServerView* view : views_)
  43     view->RemoveObserver(this);
  44
  45   views_.clear();
  46 }
  47
  48 void ServerViewDrawnTracker::OnViewDestroyed(ServerView* view) {
  49   // As views are removed before being destroyed, resulting in
  50   // OnViewHierarchyChanged() and us removing ourself as an observer, the only
  51   // view we should ever get notified of destruction on is |view_|.
  52   DCHECK_EQ(view, view_);
  53   RemoveObservers();
  54   view_ = nullptr;
  55   SetDrawn(nullptr, false);
  56 }
  57
  58 void ServerViewDrawnTracker::OnViewHierarchyChanged(ServerView* view,
  59                                                     ServerView* new_parent,
  60                                                     ServerView* old_parent) {
  61   RemoveObservers();
  62   AddObservers();
  63   const bool is_drawn = view_->IsDrawn();
  64   SetDrawn(is_drawn ? nullptr : old_parent, is_drawn);
  65 }
  66
  67 void ServerViewDrawnTracker::OnViewVisibilityChanged(ServerView* view) {
  68   const bool is_drawn = view_->IsDrawn();
  69   SetDrawn(is_drawn ? nullptr : view->parent(), is_drawn);
  70 }
  71
  72 }  // namespace mus