Convert plain C-style casts to use CFCastStrict and GetValueFromDictionary template

net/proxy/proxy_resolver_mac.cc

Index: net/proxy/proxy_resolver_mac.cc
diff --git a/net/proxy/proxy_resolver_mac.cc b/net/proxy/proxy_resolver_mac.cc
index 6c5946c9987255f00e9d19295f844ffc4f0cf8a1..7917a3e734d3623142c640c10c935365b90c0292 100644
--- a/net/proxy/proxy_resolver_mac.cc
+++ b/net/proxy/proxy_resolver_mac.cc
@@ -130,8 +130,8 @@ int ProxyResolverMac::GetProxyForURL(const GURL& query_url,
     CFRelease(result);
     return ERR_FAILED;
   }
-  DCHECK(CFGetTypeID(result) == CFArrayGetTypeID());
-  base::mac::ScopedCFTypeRef<CFArrayRef> proxy_array_ref((CFArrayRef)result);
+  base::mac::ScopedCFTypeRef<CFArrayRef> proxy_array_ref(
+      base::mac::CFCastStrict<CFArrayRef>(result));

[Mark Mentovai, 2011/11/11 17:31:50]

The old code has this as a DCHECK, but you’ve used a strict cast which is
equivalent to CHECK, with the difference that it will permit NULL. You need to
carefully consider how to transform the old code, and recognize that if you’re
changing what’s CHECKed or DCHECKed, or changing between D and non-D, you may
need to revise some of the surrounding code.

 
   // This string will be an ordered list of <proxy-uri> entries, separated by
   // semi-colons. It is the format that ProxyInfo::UseNamedProxy() expects.
@@ -141,9 +141,8 @@ int ProxyResolverMac::GetProxyForURL(const GURL& query_url,
 
   CFIndex proxy_array_count = CFArrayGetCount(proxy_array_ref.get());
   for (CFIndex i = 0; i < proxy_array_count; ++i) {
-    CFDictionaryRef proxy_dictionary =
-        (CFDictionaryRef)CFArrayGetValueAtIndex(proxy_array_ref.get(), i);
-    DCHECK(CFGetTypeID(proxy_dictionary) == CFDictionaryGetTypeID());
+    CFDictionaryRef proxy_dictionary = base::mac::CFCastStrict<CFDictionaryRef>(
+        CFArrayGetValueAtIndex(proxy_array_ref.get(), i));

[Mark Mentovai, 2011/11/11 17:31:50]

Same.

 
     // The dictionary may have the following keys:
     // - kCFProxyTypeKey : The type of the proxy
@@ -159,10 +158,10 @@ int ProxyResolverMac::GetProxyForURL(const GURL& query_url,
     // - kCFProxyAutoConfigurationURLKey : If the PAC file specifies another
     //                                     PAC file, I'm going home.
 
-    CFStringRef proxy_type =
-        (CFStringRef)base::mac::GetValueFromDictionary(proxy_dictionary,
-                                                      kCFProxyTypeKey,
-                                                      CFStringGetTypeID());
+    CFStringRef proxy_type = base::mac::CFCastStrict<CFStringRef>(

[Mark Mentovai, 2011/11/11 17:31:50]

And in this case, the old code didn’t even have a DCHECK, but you’re moving to a
strict cast.

For all of these, what you’ve written as-is may be OK, but you should explain
(in the review, not a comment) why you’ve made a behavior change. “The old code
would have crashed anyway in all of the cases where the strict cast now CHECKs”
would be a perfectly fine answer, if it’s true.

+        base::mac::GetValueFromDictionary(proxy_dictionary,
+                                          kCFProxyTypeKey,
+                                          CFStringGetTypeID()));
     ProxyServer proxy_server = ProxyServer::FromDictionary(
         GetProxyServerScheme(proxy_type),
         proxy_dictionary,