Clang plugin: Allow >1 WeakPtrFactory member in a class

tools/clang/plugins/FindBadConstructsConsumer.cpp

 // Copyright (c) 2012 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 "FindBadConstructsConsumer.h"
 
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/AST/Attr.h"
 #include "clang/Lex/Lexer.h"
 #include "llvm/Support/raw_ostream.h"
@@ skipping 706 matching lines @@
     CXXRecordDecl* record) {
   // Skip anonymous structs.
   if (record->getIdentifier() == NULL)
     return;
 
   // Iterate through members of the class.
   RecordDecl::field_iterator iter(record->field_begin()),
       the_end(record->field_end());
   SourceLocation weak_ptr_factory_location;  // Invalid initially.
   for (; iter != the_end; ++iter) {
-    // If we enter the loop but have already seen a matching WeakPtrFactory,
-    // it means there is at least one member after the factory.
-    if (weak_ptr_factory_location.isValid()) {
-      diagnostic().Report(weak_ptr_factory_location,
-                          diag_weak_ptr_factory_order_);
-    }
     const TemplateSpecializationType* template_spec_type =
         iter->getType().getTypePtr()->getAs<TemplateSpecializationType>();
+    bool param_is_weak_ptr_factory_to_self = false;
     if (template_spec_type) {
       const TemplateDecl* template_decl =
           template_spec_type->getTemplateName().getAsTemplateDecl();
-      if (template_decl && template_spec_type->getNumArgs() >= 1) {
+      if (template_decl && template_spec_type->getNumArgs() == 1) {
         if (template_decl->getNameAsString().compare("WeakPtrFactory") == 0 &&
             GetNamespace(template_decl) == "base") {
+          // Only consider WeakPtrFactory members which are specialized for the
+          // owning class.
           const TemplateArgument& arg = template_spec_type->getArg(0);
           if (arg.getAsType().getTypePtr()->getAsCXXRecordDecl() ==
               record->getTypeForDecl()->getAsCXXRecordDecl()) {
-            weak_ptr_factory_location = iter->getLocation();
+            if (!weak_ptr_factory_location.isValid()) {
+              // Save the first matching WeakPtrFactory member for the
+              // diagnostic.
+              weak_ptr_factory_location = iter->getLocation();
+            }
+            param_is_weak_ptr_factory_to_self = true;
           }
         }
       }
     }
+    // If we've already seen a WeakPtrFactory<OwningType> and this param is not
+    // one of those, it means there is at least one member after a factory.
+    if (weak_ptr_factory_location.isValid() &&
+        !param_is_weak_ptr_factory_to_self) {
+      diagnostic().Report(weak_ptr_factory_location,
+                          diag_weak_ptr_factory_order_);
+    }
   }
 }
 
 }  // namespace chrome_checker