Implement off-the-wire validation scheme for enum types.

ipc/param_traits_macros.h

 // 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.
 
 #ifndef IPC_PARAM_TRAITS_MACROS_H_
 #define IPC_PARAM_TRAITS_MACROS_H_
 
 #include <string>
 
 // Traits generation for structs.
 #define IPC_STRUCT_TRAITS_BEGIN(struct_name) \
   namespace IPC { \
     template <> \
     struct IPC_MESSAGE_EXPORT ParamTraits<struct_name> { \
       typedef struct_name param_type; \
       static void Write(Message* m, const param_type& p); \
       static bool Read(const Message* m, PickleIterator* iter, param_type* p); \
       static void Log(const param_type& p, std::string* l); \
     }; \
   }
 
 #define IPC_STRUCT_TRAITS_MEMBER(name)
 #define IPC_STRUCT_TRAITS_PARENT(type)
 #define IPC_STRUCT_TRAITS_END()
 
-// Traits generation for enums.
-#define IPC_ENUM_TRAITS(enum_name) \
+// Convenience macro for defining enumerated type traits for types which are
+// not range-checked by the IPC system. The author of the message handlers
+// is responsible for all validation. This macro should not need to be
+// subsequently redefined.
+#define IPC_ENUM_TRAITS(type) \
+  IPC_ENUM_TRAITS_VALIDATE(type, true)
+
+// Convenience macro for defining enumerated type traits for types which are
+// range-checked by the IPC system to be in the range of 0..maxvalue inclusive.
+// This macro should not need to be subsequently redefined.
+#define IPC_ENUM_TRAITS_MAX_VALUE(type, maxvalue) \
+  IPC_ENUM_TRAITS_MIN_MAX_VALUE(type, 0, maxvalue)
+
+// Convenience macro for defining enumerated type traits for types which are
+// range-checked by the IPC system to be in the range of minvalue..maxvalue
+// inclusive. This macro should not need to be subsequently redefined.
+#define IPC_ENUM_TRAITS_MIN_MAX_VALUE(type, minvalue, maxvalue)  \
+  IPC_ENUM_TRAITS_VALIDATE(type, (value >= (minvalue) && value <= (maxvalue)))
+
+// Traits generation for enums. This macro may be redefined later.
+#define IPC_ENUM_TRAITS_VALIDATE(enum_name, validation_expression) \
   namespace IPC { \
     template <> \
     struct IPC_MESSAGE_EXPORT ParamTraits<enum_name> { \
       typedef enum_name param_type; \
       static void Write(Message* m, const param_type& p); \
       static bool Read(const Message* m, PickleIterator* iter, param_type* p); \
       static void Log(const param_type& p, std::string* l); \
     }; \
   }
 
 #endif  // IPC_PARAM_TRAITS_MACROS_H_