Add support for easily casting CFTypes to NSTypes

BUG=NONE
TEST=BUILD

Review URL: http://codereview.chromium.org/5857006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@69552 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 48 insertions, 0 deletions

diff --git a/base/mac_util.h b/base/mac_util.h
index d31bf82..9da90d2 100644
--- a/base/mac_util.h
+++ b/base/mac_util.h
@@ -10,6 +10,8 @@
 #include <string>
 #include <vector>
 
+#include "base/logging.h"
+
 class FilePath;
 
 #ifdef __OBJC__
@@ -188,6 +190,52 @@ bool WasLaunchedAsHiddenLoginItem();
 void NSObjectRetain(void* obj);
 void NSObjectRelease(void* obj);
 
+// Convert toll-free bridged CFTypes to NSTypes. This does not autorelease
+// |cf_val|. This is useful for the case where there is a CFType in a call that
+// expects an NSType and the compiler is complaining about const casting
+// problems.
+// The call is used like this:
+// NSString *foo = CFToNSCast(CFSTR("Hello"));
+// The macro magic below is to enforce safe casting. It could possibly have
+// been done using template function specialization, but template function
+// specialization doesn't always work intuitively,
+// (http://www.gotw.ca/publications/mill17.htm) so the trusty combination
+// of macros and function overloading is used instead.
+
+#define CF_TO_NS_CAST(TypeCF, TypeNS) \
+TypeNS* CFToNSCast(TypeCF cf_val) { \
+  TypeNS* ns_val = \
+      const_cast<id>(reinterpret_cast<const struct objc_object*>(cf_val)); \
+  DCHECK(!ns_val || [ns_val isKindOfClass:[TypeNS class]]); \
+  return ns_val; \
+}
+
+// List of toll-free bridged types taken from:
+// http://www.cocoadev.com/index.pl?TollFreeBridged
+
+CF_TO_NS_CAST(CFArrayRef, NSArray);
+CF_TO_NS_CAST(CFMutableArrayRef, NSMutableArray);
+CF_TO_NS_CAST(CFAttributedStringRef, NSAttributedString);
+CF_TO_NS_CAST(CFMutableAttributedStringRef, NSMutableAttributedString);
+CF_TO_NS_CAST(CFCalendarRef, NSCalendar);
+CF_TO_NS_CAST(CFCharacterSetRef, NSCharacterSet);
+CF_TO_NS_CAST(CFMutableCharacterSetRef, NSMutableCharacterSet);
+CF_TO_NS_CAST(CFDataRef, NSData);
+CF_TO_NS_CAST(CFMutableDataRef, NSMutableData);
+CF_TO_NS_CAST(CFDateRef, NSDate);
+CF_TO_NS_CAST(CFDictionaryRef, NSDictionary);
+CF_TO_NS_CAST(CFMutableDictionaryRef, NSMutableDictionary);
+CF_TO_NS_CAST(CFNumberRef, NSNumber);
+CF_TO_NS_CAST(CFRunLoopTimerRef, NSTimer);
+CF_TO_NS_CAST(CFSetRef, NSSet);
+CF_TO_NS_CAST(CFMutableSetRef, NSMutableSet);
+CF_TO_NS_CAST(CFStringRef, NSString);
+CF_TO_NS_CAST(CFMutableStringRef, NSMutableString);
+CF_TO_NS_CAST(CFURLRef, NSURL);
+CF_TO_NS_CAST(CFTimeZoneRef, NSTimeZone);
+CF_TO_NS_CAST(CFReadStreamRef, NSInputStream);
+CF_TO_NS_CAST(CFWriteStreamRef, NSOutputStream);
+
 }  // namespace mac_util
 
 #endif  // BASE_MAC_UTIL_H_