Create ObjCCast<>() and ObjCCastStrict<>() methods

base/mac/foundation_util_unittest.mm

Index: base/mac/foundation_util_unittest.mm
diff --git a/base/mac/foundation_util_unittest.mm b/base/mac/foundation_util_unittest.mm
index cfd4fc60b3e335c69aab24d25af372108df0fc6f..8f2f899e5e33e9cfec35f7b1f4b4cfa4ccd78591 100644
--- a/base/mac/foundation_util_unittest.mm
+++ b/base/mac/foundation_util_unittest.mm
@@ -159,3 +159,107 @@ TEST(FoundationUtilTest, CFCast) {
   EXPECT_FALSE(base::mac::CFCastStrict<CFSetRef>(NULL));
   EXPECT_FALSE(base::mac::CFCastStrict<CFStringRef>(NULL));
 }
+
+TEST(FoundationUtilTest, ObjCCast) {
+  id test_array = [NSArray arrayWithObjects:

[Mark Mentovai, 2011/10/19 22:59:32]

Let’s get a ScopedNSAutoreleasePool in here to make sure these objects are
deallocated when exiting the function.

+                             @"whoomp", @"there", @"it", @"is", nil];
+  id test_array_mutable = [NSMutableArray arrayWithObjects:
+                                            @"a man", @"a plan",
+                                            @"a canal", @"panama",
+                                            nil];
+  id test_data = [NSData data];
+  id test_date = [NSDate date];
+  id test_dict = [NSDictionary
+                   dictionaryWithObject:[NSNumber numberWithInt:42]

[Mark Mentovai, 2011/10/19 22:59:32]

Formatting nit: I find it clearer to do
  id test_dict =
      [NSDictionary dictionaryWithObject:…

+                                 forKey:@"meaning"];
+  id test_dict_mutable = [NSMutableDictionary dictionaryWithCapacity:10];
+  id test_number = [NSNumber numberWithInt:42];
+  id test_null = [NSNull null];
+  id test_set = [NSSet setWithObject:@"string object"];
+  id test_set_mutable = [NSMutableSet setWithCapacity:10];
+  id test_str = @"bonjour";

[Mark Mentovai, 2011/10/19 22:59:32]

As in the CF test:

This one is test_str_const. You can have test_str created from +[NSString
string] .

+  id test_str_mutable = [NSMutableString stringWithCapacity:10];
+
+  // Make sure the allocations of CF types are good.

[Mark Mentovai, 2011/10/19 22:59:32]

Adjust the comments because this test isn’t about CF.

+  EXPECT_TRUE(test_array);
+  EXPECT_TRUE(test_array_mutable);
+  EXPECT_TRUE(test_data);
+  EXPECT_TRUE(test_date);
+  EXPECT_TRUE(test_dict);
+  EXPECT_TRUE(test_dict_mutable);
+  EXPECT_TRUE(test_number);
+  EXPECT_TRUE(test_null);
+  EXPECT_TRUE(test_set);
+  EXPECT_TRUE(test_set_mutable);
+  EXPECT_TRUE(test_str);
+  EXPECT_TRUE(test_str_mutable);
+
+  // Casting the id correctly provides the same pointer.
+  EXPECT_EQ(test_array, base::mac::ObjCCast<NSArray>(test_array));
+  EXPECT_EQ(test_array_mutable,
+            base::mac::ObjCCast<NSArray>(test_array_mutable));
+  EXPECT_EQ(test_data, base::mac::ObjCCast<NSData>(test_data));
+  EXPECT_EQ(test_date, base::mac::ObjCCast<NSDate>(test_date));
+  EXPECT_EQ(test_dict, base::mac::ObjCCast<NSDictionary>(test_dict));
+  EXPECT_EQ(test_dict_mutable,
+            base::mac::ObjCCast<NSDictionary>(test_dict_mutable));
+  EXPECT_EQ(test_number, base::mac::ObjCCast<NSNumber>(test_number));
+  EXPECT_EQ(test_null, base::mac::ObjCCast<NSNull>(test_null));
+  EXPECT_EQ(test_set, base::mac::ObjCCast<NSSet>(test_set));
+  EXPECT_EQ(test_set_mutable, base::mac::ObjCCast<NSSet>(test_set_mutable));
+  EXPECT_EQ(test_str, base::mac::ObjCCast<NSString>(test_str));
+  EXPECT_EQ(test_str_mutable,
+            base::mac::ObjCCast<NSString>(test_str_mutable));
+
+  // When given an incorrect ObjC cast, provide NULL.

[Mark Mentovai, 2011/10/19 22:59:32]

nil.

+  EXPECT_FALSE(base::mac::ObjCCast<NSString>(test_array));
+  EXPECT_FALSE(base::mac::ObjCCast<NSString>(test_array_mutable));
+  EXPECT_FALSE(base::mac::ObjCCast<NSString>(test_data));
+  EXPECT_FALSE(base::mac::ObjCCast<NSSet>(test_date));
+  EXPECT_FALSE(base::mac::ObjCCast<NSSet>(test_dict));
+  EXPECT_FALSE(base::mac::ObjCCast<NSNumber>(test_dict_mutable));
+  EXPECT_FALSE(base::mac::ObjCCast<NSNull>(test_number));
+  EXPECT_FALSE(base::mac::ObjCCast<NSDictionary>(test_null));
+  EXPECT_FALSE(base::mac::ObjCCast<NSDictionary>(test_set));
+  EXPECT_FALSE(base::mac::ObjCCast<NSDate>(test_set_mutable));
+  EXPECT_FALSE(base::mac::ObjCCast<NSData>(test_str));
+  EXPECT_FALSE(base::mac::ObjCCast<NSArray>(test_str_mutable));
+
+  // Giving a NULL provides a NULL.

[Mark Mentovai, 2011/10/19 22:59:32]

nil, and nil as the argument to each of these casts.

+  EXPECT_FALSE(base::mac::ObjCCast<NSArray>(NULL));
+  EXPECT_FALSE(base::mac::ObjCCast<NSData>(NULL));
+  EXPECT_FALSE(base::mac::ObjCCast<NSDate>(NULL));
+  EXPECT_FALSE(base::mac::ObjCCast<NSDictionary>(NULL));
+  EXPECT_FALSE(base::mac::ObjCCast<NSNull>(NULL));
+  EXPECT_FALSE(base::mac::ObjCCast<NSNumber>(NULL));
+  EXPECT_FALSE(base::mac::ObjCCast<NSSet>(NULL));
+  EXPECT_FALSE(base::mac::ObjCCast<NSString>(NULL));
+
+  // ObjCCastStrict: correct cast results in correct pointer being returned.
+  EXPECT_EQ(test_array, base::mac::ObjCCastStrict<NSArray>(test_array));
+  EXPECT_EQ(test_array_mutable,
+            base::mac::ObjCCastStrict<NSArray>(test_array_mutable));
+  EXPECT_EQ(test_data, base::mac::ObjCCastStrict<NSData>(test_data));
+  EXPECT_EQ(test_date, base::mac::ObjCCastStrict<NSDate>(test_date));
+  EXPECT_EQ(test_dict, base::mac::ObjCCastStrict<NSDictionary>(test_dict));
+  EXPECT_EQ(test_dict_mutable,
+            base::mac::ObjCCastStrict<NSDictionary>(test_dict_mutable));
+  EXPECT_EQ(test_number, base::mac::ObjCCastStrict<NSNumber>(test_number));
+  EXPECT_EQ(test_null, base::mac::ObjCCastStrict<NSNull>(test_null));
+  EXPECT_EQ(test_set, base::mac::ObjCCastStrict<NSSet>(test_set));
+  EXPECT_EQ(test_set_mutable,
+            base::mac::ObjCCastStrict<NSSet>(test_set_mutable));
+  EXPECT_EQ(test_str, base::mac::ObjCCastStrict<NSString>(test_str));
+  EXPECT_EQ(test_str_mutable,
+            base::mac::ObjCCastStrict<NSString>(test_str_mutable));
+
+  // ObjCCastStrict: Giving a NULL provides a NULL.

[Mark Mentovai, 2011/10/19 22:59:32]

And again here.

+  EXPECT_FALSE(base::mac::ObjCCastStrict<NSArray>(NULL));
+  EXPECT_FALSE(base::mac::ObjCCastStrict<NSData>(NULL));
+  EXPECT_FALSE(base::mac::ObjCCastStrict<NSDate>(NULL));
+  EXPECT_FALSE(base::mac::ObjCCastStrict<NSDictionary>(NULL));
+  EXPECT_FALSE(base::mac::ObjCCastStrict<NSNull>(NULL));
+  EXPECT_FALSE(base::mac::ObjCCastStrict<NSNumber>(NULL));
+  EXPECT_FALSE(base::mac::ObjCCastStrict<NSSet>(NULL));
+  EXPECT_FALSE(base::mac::ObjCCastStrict<NSString>(NULL));
+}