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

net/proxy/proxy_resolver_mac.cc

 // Copyright (c) 2011 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 "net/proxy/proxy_resolver_mac.h"
 
 #include <CoreFoundation/CoreFoundation.h>
 #include <CoreServices/CoreServices.h>
 
 #include "base/logging.h"
@@ skipping 112 matching lines @@
   CFRunLoopRunInMode(private_runloop_mode, DBL_MAX, false);
   CFRunLoopRemoveSource(CFRunLoopGetCurrent(), runloop_source.get(),
                         private_runloop_mode);
   DCHECK(result != NULL);
 
   if (CFGetTypeID(result) == CFErrorGetTypeID()) {
     // TODO(avi): do something better than this
     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.
   //    proxy-uri = [<proxy-scheme>"://"]<proxy-host>":"<proxy-port>
   // (This also includes entries for direct connection, as "direct://").
   std::string proxy_uri_list;
 
   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
     // - kCFProxyHostNameKey
     // - kCFProxyPortNumberKey : The meat we're after.
     // - kCFProxyUsernameKey
     // - kCFProxyPasswordKey : Despite the existence of these keys in the
     //                         documentation, they're never populated. Even if a
     //                         username/password were to be set in the network
     //                         proxy system preferences, we'd need to fetch it
     //                         from the Keychain ourselves. CFProxy is such a
     //                         tease.
     // - 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,
         kCFProxyHostNameKey,
         kCFProxyPortNumberKey);
     if (!proxy_server.is_valid())
       continue;
 
     if (!proxy_uri_list.empty())
       proxy_uri_list += ";";
@@ skipping 26 matching lines @@
 }
 
 int ProxyResolverMac::SetPacScript(
     const scoped_refptr<ProxyResolverScriptData>& script_data,
     OldCompletionCallback* /*callback*/) {
   script_data_ = script_data;
   return OK;
 }
 
 }  // namespace net