Made return types of various Value::DeepCopy() implementations more specific

base/values_unittest.cc

 // 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 <limits>
 
 #include "base/scoped_ptr.h"
 #include "base/string16.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
@@ skipping 305 matching lines @@
   EXPECT_FALSE(dict.Get("this.isnt.expanded", &value3));
   Value* value4;
   ASSERT_TRUE(dict.GetWithoutPathExpansion("this.isnt.expanded", &value4));
   EXPECT_EQ(Value::TYPE_NULL, value4->GetType());
 }
 
 TEST_F(ValuesTest, DeepCopy) {
   DictionaryValue original_dict;
   Value* original_null = Value::CreateNullValue();
   original_dict.Set("null", original_null);
-  Value* original_bool = Value::CreateBooleanValue(true);
+  FundamentalValue* original_bool = Value::CreateBooleanValue(true);
   original_dict.Set("bool", original_bool);
-  Value* original_int = Value::CreateIntegerValue(42);
+  FundamentalValue* original_int = Value::CreateIntegerValue(42);
   original_dict.Set("int", original_int);
-  Value* original_real = Value::CreateRealValue(3.14);
+  FundamentalValue* original_real = Value::CreateRealValue(3.14);
   original_dict.Set("real", original_real);
-  Value* original_string = Value::CreateStringValue("hello");
+  StringValue* original_string = Value::CreateStringValue("hello");
   original_dict.Set("string", original_string);
-  Value* original_string16 = Value::CreateStringValue(ASCIIToUTF16("hello16"));
+  StringValue* original_string16 =
+      Value::CreateStringValue(ASCIIToUTF16("hello16"));
   original_dict.Set("string16", original_string16);
 
   char* original_buffer = new char[42];
   memset(original_buffer, '!', 42);
   BinaryValue* original_binary = Value::CreateBinaryValue(original_buffer, 42);
   original_dict.Set("binary", original_binary);
 
   ListValue* original_list = new ListValue();
-  Value* original_list_element_0 = Value::CreateIntegerValue(0);
+  FundamentalValue* original_list_element_0 = Value::CreateIntegerValue(0);
   original_list->Append(original_list_element_0);
-  Value* original_list_element_1 = Value::CreateIntegerValue(1);
+  FundamentalValue* original_list_element_1 = Value::CreateIntegerValue(1);
   original_list->Append(original_list_element_1);
   original_dict.Set("list", original_list);
 
-  scoped_ptr<DictionaryValue> copy_dict(
-      static_cast<DictionaryValue*>(original_dict.DeepCopy()));
+  scoped_ptr<DictionaryValue> copy_dict(original_dict.DeepCopy());
   ASSERT_TRUE(copy_dict.get());
   ASSERT_NE(copy_dict.get(), &original_dict);
 
   Value* copy_null = NULL;
   ASSERT_TRUE(copy_dict->Get("null", &copy_null));
   ASSERT_TRUE(copy_null);
   ASSERT_NE(copy_null, original_null);
   ASSERT_TRUE(copy_null->IsType(Value::TYPE_NULL));
 
   Value* copy_bool = NULL;
@@ skipping 97 matching lines @@
 
   DictionaryValue dv;
   dv.SetBoolean("a", false);
   dv.SetInteger("b", 2);
   dv.SetReal("c", 2.5);
   dv.SetString("d1", "string");
   dv.SetString("d2", ASCIIToUTF16("http://google.com"));
   dv.Set("e", Value::CreateNullValue());
 
   scoped_ptr<DictionaryValue> copy;
-  copy.reset(static_cast<DictionaryValue*>(dv.DeepCopy()));
+  copy.reset(dv.DeepCopy());
   EXPECT_TRUE(dv.Equals(copy.get()));
 
   ListValue* list = new ListValue;
   list->Append(Value::CreateNullValue());
   list->Append(new DictionaryValue);
   dv.Set("f", list);
 
   EXPECT_FALSE(dv.Equals(copy.get()));
   copy->Set("f", list->DeepCopy());
   EXPECT_TRUE(dv.Equals(copy.get()));
 
   list->Append(Value::CreateBooleanValue(true));
   EXPECT_FALSE(dv.Equals(copy.get()));
 
   // Check if Equals detects differences in only the keys.
-  copy.reset(static_cast<DictionaryValue*>(dv.DeepCopy()));
+  copy.reset(dv.DeepCopy());
   EXPECT_TRUE(dv.Equals(copy.get()));
   copy->Remove("a", NULL);
   copy->SetBoolean("aa", false);
   EXPECT_FALSE(dv.Equals(copy.get()));
 }
 
 TEST_F(ValuesTest, StaticEquals) {
   scoped_ptr<Value> null1(Value::CreateNullValue());
   scoped_ptr<Value> null2(Value::CreateNullValue());
   EXPECT_TRUE(Value::Equals(null1.get(), null2.get()));
   EXPECT_TRUE(Value::Equals(NULL, NULL));
 
   scoped_ptr<Value> i42(Value::CreateIntegerValue(42));
   scoped_ptr<Value> j42(Value::CreateIntegerValue(42));
   scoped_ptr<Value> i17(Value::CreateIntegerValue(17));
   EXPECT_TRUE(Value::Equals(i42.get(), i42.get()));
   EXPECT_TRUE(Value::Equals(j42.get(), i42.get()));
   EXPECT_TRUE(Value::Equals(i42.get(), j42.get()));
   EXPECT_FALSE(Value::Equals(i42.get(), i17.get()));
   EXPECT_FALSE(Value::Equals(i42.get(), NULL));
   EXPECT_FALSE(Value::Equals(NULL, i42.get()));
 
   // NULL and Value::CreateNullValue() are intentionally different: We need
   // support for NULL as a return value for "undefined" without caring for
   // ownership of the pointer.
   EXPECT_FALSE(Value::Equals(null1.get(), NULL));
   EXPECT_FALSE(Value::Equals(NULL, null1.get()));
 }
 
+TEST_F(ValuesTest, DeepCopyCovariantReturnTypes) {
+  DictionaryValue original_dict;
+  Value* original_null = Value::CreateNullValue();
+  original_dict.Set("null", original_null);
+  FundamentalValue* original_bool = Value::CreateBooleanValue(true);
+  original_dict.Set("bool", original_bool);
+  FundamentalValue* original_int = Value::CreateIntegerValue(42);
+  original_dict.Set("int", original_int);
+  FundamentalValue* original_real = Value::CreateRealValue(3.14);
+  original_dict.Set("real", original_real);
+  StringValue* original_string = Value::CreateStringValue("hello");
+  original_dict.Set("string", original_string);
+  StringValue* original_string16 =
+      Value::CreateStringValue(ASCIIToUTF16("hello16"));
+  original_dict.Set("string16", original_string16);
+
+  char* original_buffer = new char[42];
+  memset(original_buffer, '!', 42);
+  BinaryValue* original_binary = Value::CreateBinaryValue(original_buffer, 42);
+  original_dict.Set("binary", original_binary);
+
+  ListValue* original_list = new ListValue();
+  FundamentalValue* original_list_element_0 = Value::CreateIntegerValue(0);
+  original_list->Append(original_list_element_0);
+  FundamentalValue* original_list_element_1 = Value::CreateIntegerValue(1);
+  original_list->Append(original_list_element_1);
+  original_dict.Set("list", original_list);
+
+  Value* original_dict_value = &original_dict;
+  Value* original_bool_value = original_bool;
+  Value* original_int_value = original_int;
+  Value* original_real_value = original_real;
+  Value* original_string_value = original_string;
+  Value* original_string16_value = original_string16;
+  Value* original_binary_value = original_binary;
+  Value* original_list_value = original_list;
+
+  scoped_ptr<Value> copy_dict_value(original_dict_value->DeepCopy());
+  scoped_ptr<Value> copy_bool_value(original_bool_value->DeepCopy());
+  scoped_ptr<Value> copy_int_value(original_int_value->DeepCopy());
+  scoped_ptr<Value> copy_real_value(original_real_value->DeepCopy());
+  scoped_ptr<Value> copy_string_value(original_string_value->DeepCopy());
+  scoped_ptr<Value> copy_string16_value(original_string16_value->DeepCopy());
+  scoped_ptr<Value> copy_binary_value(original_binary_value->DeepCopy());
+  scoped_ptr<Value> copy_list_value(original_list_value->DeepCopy());
+
+  EXPECT_TRUE(original_dict_value->Equals(copy_dict_value.get()));
+  EXPECT_TRUE(original_bool_value->Equals(copy_bool_value.get()));
+  EXPECT_TRUE(original_int_value->Equals(copy_int_value.get()));
+  EXPECT_TRUE(original_real_value->Equals(copy_real_value.get()));
+  EXPECT_TRUE(original_string_value->Equals(copy_string_value.get()));
+  EXPECT_TRUE(original_string16_value->Equals(copy_string16_value.get()));
+  EXPECT_TRUE(original_binary_value->Equals(copy_binary_value.get()));
+  EXPECT_TRUE(original_list_value->Equals(copy_list_value.get()));
+}
+
 TEST_F(ValuesTest, RemoveEmptyChildren) {
   scoped_ptr<DictionaryValue> root(new DictionaryValue);
   // Remove empty lists and dictionaries.
   root->Set("empty_dict", new DictionaryValue);
   root->Set("empty_list", new ListValue);
   root->SetWithoutPathExpansion("a.b.c.d.e", new DictionaryValue);
   root.reset(root->DeepCopyWithoutEmptyChildren());
   EXPECT_TRUE(root->empty());
 
   // Make sure we don't prune too much.
@@ skipping 99 matching lines @@
   EXPECT_TRUE(res_sub_dict->GetString("sub_base_key", &sub_base_key_value));
   EXPECT_EQ("sub_base_key_value_base", sub_base_key_value); // Preserved.
   std::string sub_collide_key_value;
   EXPECT_TRUE(res_sub_dict->GetString("sub_collide_key",
                                       &sub_collide_key_value));
   EXPECT_EQ("sub_collide_key_value_merge", sub_collide_key_value); // Replaced.
   std::string sub_merge_key_value;
   EXPECT_TRUE(res_sub_dict->GetString("sub_merge_key", &sub_merge_key_value));
   EXPECT_EQ("sub_merge_key_value_merge", sub_merge_key_value); // Merged in.
 }