Create a nicer interface for base::mac::GetValueFromDictionary

base/mac/foundation_util.h

Index: base/mac/foundation_util.h
diff --git a/base/mac/foundation_util.h b/base/mac/foundation_util.h
index f7821de08cdb09bca58aaca59da82bd689407e29..c02b9d7d1b2bac2b484e730adfbd4d84420d2dd3 100644
--- a/base/mac/foundation_util.h
+++ b/base/mac/foundation_util.h
@@ -102,6 +102,11 @@ BASE_EXPORT CFTypeRef GetValueFromDictionary(CFDictionaryRef dict,
                                              CFStringRef key,
                                              CFTypeID expected_type);
 
+// Utility function to pull out a value from a dictionary, check its type, and
+// return it.  Returns NULL if the key is not present or of the wrong type.
+BASE_EXPORT template<class T>
+T GetValueFromDictionary(CFDictionaryRef dict, CFStringRef key);

[Nico, 2011/11/11 23:08:36]

I don't understand why this is a template function instead of

GetCFStringFromDictionary();
GetCFNumberFromDictionary();

etc.

[KushalP, 2011/11/11 23:13:35]

I would've thought the template function is a cleaner way of using the method.

You can do something similar to your example with:

base::mac::GetValueFromDictionary<CFStringRef>();
base::mac::GetValueFromDictionary<CFNumberRef>();

+
 // Retain/release calls for memory management in C++.
 BASE_EXPORT void NSObjectRetain(void* obj);
 BASE_EXPORT void NSObjectRelease(void* obj);
@@ -265,6 +270,12 @@ T* ObjCCastStrict(id objc_val) {
 
 #endif  // defined(__OBJC__)
 
+// Utility function to pull out a value from a dictionary, check its type, and
+// return it.  Returns NULL if the key is not present or of the wrong type.
+// Is a cleaner implementation of base::mac::GetValueFromDictionary() above.
+BASE_EXPORT template<class T>
+T GetValueFromDictionary(CFDictionaryRef dict, CFStringRef key);
+
 }  // namespace mac
 }  // namespace base