ui/base/view_prop.cc

   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 #include "ui/base/view_prop.h"
   6
   7 #include <set>
   8
   9 namespace ui {
  10
  11 // Maints the actual view, key and data.
  12 class ViewProp::Data : public base::RefCounted<ViewProp::Data> {
  13  public:
  14   // Returns the Data* for the view/key pair. If |create| is false and |Get|
  15   // has not been invoked for the view/key pair, NULL is returned.
  16   static void Get(gfx::AcceleratedWidget view,
  17                   const char* key,
  18                   bool create,
  19                   scoped_refptr<Data>* data) {
  20     if (!data_set_)
  21       data_set_ = new DataSet;
  22     scoped_refptr<Data> new_data(new Data(view, key));
  23     DataSet::const_iterator i = data_set_->find(new_data.get());
  24     if (i != data_set_->end()) {
  25       *data = *i;
  26       return;
  27     }
  28     if (!create)
  29       return;
  30     data_set_->insert(new_data.get());
  31     *data = new_data.get();
  32   }
  33
  34   // The data.
  35   void set_data(void* data) { data_ = data; }
  36   void* data() const { return data_; }
  37
  38   const char* key() const { return key_; }
  39
  40  private:
  41   friend class base::RefCounted<Data>;
  42
  43   // Used to order the Data in the map.
  44   class DataComparator {
  45    public:
  46     bool operator()(const Data* d1, const Data* d2) const {
  47       return (d1->view_ == d2->view_) ? (d1->key_ < d2->key_) :
  48                                         (d1->view_ < d2->view_);
  49     }
  50   };
  51
  52   typedef std::set<Data*, DataComparator> DataSet;
  53
  54   Data(gfx::AcceleratedWidget view, const char* key)
  55       : view_(view),
  56         key_(key),
  57         data_(NULL) {}
  58
  59   ~Data() {
  60     DataSet::iterator i = data_set_->find(this);
  61     // Also check for equality using == as |Get| creates dummy values in order
  62     // to look up a value.
  63     if (i != data_set_->end() && *i == this)
  64       data_set_->erase(i);
  65   }
  66
  67   // The existing set of Data is stored here. ~Data removes from the set.
  68   static DataSet* data_set_;
  69
  70   const gfx::AcceleratedWidget view_;
  71   const char* key_;
  72   void* data_;
  73
  74   DISALLOW_COPY_AND_ASSIGN(Data);
  75 };
  76
  77 // static
  78 ViewProp::Data::DataSet* ViewProp::Data::data_set_ = NULL;
  79
  80 ViewProp::ViewProp(gfx::AcceleratedWidget view, const char* key, void* data) {
  81   Data::Get(view, key, true, &data_);
  82   data_->set_data(data);
  83 }
  84
  85 ViewProp::~ViewProp() {
  86   // This is done to provide similar semantics to SetProp. In particular it's
  87   // assumed that ~ViewProp should behave as though RemoveProp was invoked.
  88   data_->set_data(NULL);
  89 }
  90
  91 // static
  92 void* ViewProp::GetValue(gfx::AcceleratedWidget view, const char* key) {
  93   scoped_refptr<Data> data;
  94   Data::Get(view, key, false, &data);
  95   return data.get() ? data->data() : NULL;
  96 }
  97
  98 // static
  99 const char* ViewProp::Key() const {
 100   return data_->key();
 101 }
 102
 103 }  // namespace ui