Converts usage of SetProp/GetProp to a map. Even after making sure we

app/view_prop.cc

Index: app/view_prop.cc
diff --git a/app/view_prop.cc b/app/view_prop.cc
new file mode 100644
index 0000000000000000000000000000000000000000..778f381f5a400a3f46a1373a3e417ee3a631ddda
--- /dev/null
+++ b/app/view_prop.cc
@@ -0,0 +1,106 @@
+// Copyright (c) 2010 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.
+
+#include "app/view_prop.h"
+
+#include <set>
+
+namespace app {
+namespace win {
+
+// Maints the actual view, key and data.
+class ViewProp::Data : public base::RefCounted<ViewProp::Data> {
+ public:
+  // Returns the Data* for the view/key pair. If |create| is false and |Get|
+  // has not been invoked for the view/key pair, NULL is returned.
+  static void Get(gfx::NativeView view,
+                  const char* key,
+                  bool create,
+                  scoped_refptr<Data>* data) {
+    if (!data_set_)
+      data_set_ = new DataSet;
+    scoped_refptr<Data> new_data(new Data(view, key));
+    DataSet::const_iterator i = data_set_->find(new_data.get());
+    if (i != data_set_->end()) {
+      *data = *i;
+      return;
+    }
+    if (!create)
+      return;
+    data_set_->insert(new_data.get());
+    *data = new_data.get();
+  }
+
+  // The data.
+  void set_data(void* data) { data_ = data; }

[cpu_(ooo_6.6-7.5), 2010/11/18 22:49:15]

shouldn't set to NULL remove the item? if so above Get would need to deal with
that.

[sky, 2010/11/18 23:16:31]

data_ is just the arbitrary value and it's used by these classes (only by the
users of ViewProp). The Data instance is removed from the map when there are no
more references. But maybe I'm misunderstanding your question?

+  void* data() const { return data_; }
+
+  const char* key() const { return key_; }
+
+ private:
+  friend class base::RefCounted<Data>;
+
+  // Used to order the Data in the map.
+  class DataComparator {
+   public:
+    bool operator()(const Data* d1, const Data* d2) const {
+      return (d1->view_ == d2->view_) ? (d1->key_ < d2->key_) :
+                                        (d1->view_ < d2->view_);
+    }
+  };
+
+  typedef std::set<Data*, DataComparator> DataSet;
+
+  Data(gfx::NativeView view, const char* key)
+      : view_(view),
+        key_(key),
+        data_(NULL) {}
+
+  ~Data() {
+    DataSet::iterator i = data_set_->find(this);
+    // Also check for equality using == as |Get| creates dummy values in order
+    // to look up a value.
+    if (i != data_set_->end() && *i == this)
+      data_set_->erase(i);
+  }
+
+  // The existing set of Data is stored here. ~Data removes from the set.
+  static DataSet* data_set_;
+
+  const gfx::NativeView view_;
+  const char* key_;
+  void* data_;
+
+  DISALLOW_COPY_AND_ASSIGN(Data);
+};
+
+// static
+ViewProp::Data::DataSet* ViewProp::Data::data_set_ = NULL;
+
+ViewProp::ViewProp(gfx::NativeView view, const char* key, void* data) {
+  Data::Get(view, key, true, &data_);
+  data_->set_data(data);
+}
+
+ViewProp::~ViewProp() {
+  // This is done to provide similar semantics to SetProp. In particular it's
+  // assumed that ~ViewProp should behave as though RemoveProp was invoked.
+  data_->set_data(NULL);
+}
+
+// static
+void* ViewProp::GetValue(gfx::NativeView view, const char* key) {
+  scoped_refptr<Data> data;
+  Data::Get(view, key, false, &data);
+  return data.get() ? data->data() : NULL;
+}
+
+// static
+const char* ViewProp::Key() const {
+  return data_->key();
+}
+
+}  // namespace win
+
+}  // namespace app