components/view_manager/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/view_manager/server_view_drawn_tracker.h"
   6
   7 #include "components/view_manager/server_view.h"
   8 #include "components/view_manager/server_view_drawn_tracker_observer.h"
   9
  10 namespace view_manager {
  11
  12 ServerViewDrawnTracker::ServerViewDrawnTracker(
  13     ServerView* root,
  14     ServerView* view,
  15     ServerViewDrawnTrackerObserver* observer)
  16     : root_(root),
  17       view_(view),
  18       observer_(observer),
  19       drawn_(view->IsDrawn(root)) {
  20   AddObservers();
  21 }
  22
  23 ServerViewDrawnTracker::~ServerViewDrawnTracker() {
  24   RemoveObservers();
  25 }
  26
  27 void ServerViewDrawnTracker::SetDrawn(ServerView* ancestor, bool drawn) {
  28   if (drawn == drawn_)
  29     return;
  30
  31   drawn_ = drawn;
  32   observer_->OnDrawnStateChanged(ancestor, view_, drawn);
  33 }
  34
  35 void ServerViewDrawnTracker::AddObservers() {
  36   if (!view_)
  37     return;
  38
  39   for (ServerView* v = view_; v; v = v->parent()) {
  40     v->AddObserver(this);
  41     views_.insert(v);
  42   }
  43 }
  44
  45 void ServerViewDrawnTracker::RemoveObservers() {
  46   for (ServerView* view : views_)
  47     view->RemoveObserver(this);
  48
  49   views_.clear();
  50 }
  51
  52 void ServerViewDrawnTracker::OnViewDestroyed(ServerView* view) {
  53   // As views are removed before being destroyed, resulting in
  54   // OnViewHierarchyChanged() and us removing ourself as an observer, the only
  55   // view we should ever get notified of destruction on is |view_|.
  56   DCHECK_EQ(view, view_);
  57   RemoveObservers();
  58   view_ = nullptr;
  59   SetDrawn(nullptr, false);
  60 }
  61
  62 void ServerViewDrawnTracker::OnViewHierarchyChanged(ServerView* view,
  63                                                     ServerView* new_parent,
  64                                                     ServerView* old_parent) {
  65   RemoveObservers();
  66   AddObservers();
  67   const bool is_drawn = view_->IsDrawn(root_);
  68   SetDrawn(is_drawn ? nullptr : old_parent, is_drawn);
  69 }
  70
  71 void ServerViewDrawnTracker::OnViewVisibilityChanged(ServerView* view) {
  72   const bool is_drawn = view_->IsDrawn(root_);
  73   SetDrawn(is_drawn ? nullptr : view->parent(), is_drawn);
  74 }
  75
  76 }  // namespace view_manager