From d0edb425f50b9c3c11a417ce15a0d1ca75e225b5 Mon Sep 17 00:00:00 2001
From: Jeff Walden <jwalden@mit.edu>
Date: Thu, 10 Nov 2011 14:19:28 -0800
Subject: [PATCH] Bug 701183 - Make MOZ_DELETE use deleted function syntax in
 gcc when it's possible to do so without causing a warning.  r=cjones

--HG--
extra : rebase_source : 6f452c9cc9dcdc772991ee1056975bf7b0b4bb5b
---
 mfbt/RangedPtr.h |  6 +++---
 mfbt/RefPtr.h    |  4 ++--
 mfbt/Types.h     | 33 +++++++++++++++++++++------------
 3 files changed, 26 insertions(+), 17 deletions(-)

diff --git a/mfbt/RangedPtr.h b/mfbt/RangedPtr.h
index ce12479800a..82726755dd1 100644
--- a/mfbt/RangedPtr.h
+++ b/mfbt/RangedPtr.h
@@ -268,9 +268,9 @@ class RangedPtr
     }
 
   private:
-    RangedPtr();
-    T* operator&();
-    operator T*() const;
+    RangedPtr() MOZ_DELETE;
+    T* operator&() MOZ_DELETE;
+    operator T*() const MOZ_DELETE;
 };
 
 } /* namespace mozilla */
diff --git a/mfbt/RefPtr.h b/mfbt/RefPtr.h
index 3c9be7ff8af..1f480c3cccf 100644
--- a/mfbt/RefPtr.h
+++ b/mfbt/RefPtr.h
@@ -269,8 +269,8 @@ private:
     RefPtr<T>& refPtr;
     T* tmp;
 
-    OutParamRef();
-    OutParamRef& operator=(const OutParamRef&);
+    OutParamRef() MOZ_DELETE;
+    OutParamRef& operator=(const OutParamRef&) MOZ_DELETE;
 };
 
 /**
diff --git a/mfbt/Types.h b/mfbt/Types.h
index d78c87f943f..7b0a00b239e 100644
--- a/mfbt/Types.h
+++ b/mfbt/Types.h
@@ -93,19 +93,21 @@
 /*
  * MOZ_DELETE, specified immediately prior to the ';' terminating an undefined-
  * method declaration, attempts to delete that method from the corresponding
- * class.  An attempt to use the method will produce an error *at link time*,
- * not at compile time, in compilers for which this macro can be implemented.
- * For example, you can use this macro to produce classes with no implicit copy
- * constructor or assignment operator:
+ * class.  An attempt to use the method will always produce an error *at compile
+ * time* (instead of sometimes as late as link time) when this macro can be
+ * implemented.  For example, you can use MOZ_DELETE to produce classes with no
+ * implicit copy constructor or assignment operator:
  *
- *   struct NonCopyable {
+ *   struct NonCopyable
+ *   {
  *     private:
  *       NonCopyable(const NonCopyable& other) MOZ_DELETE;
  *       void operator=(const NonCopyable& other) MOZ_DELETE;
  *   };
  *
- * If MOZ_DELETE can't be implemented for the current compiler, it will still
- * cause an error, but at link time rather than compile time.
+ * If MOZ_DELETE can't be implemented for the current compiler, use of the
+ * annotated method will still cause an error, but the error might occur at link
+ * time in some cases rather than at compile time.
  *
  * MOZ_DELETE relies on C++11 functionality not universally implemented.  As a
  * backstop, method declarations using MOZ_DELETE should be private.
@@ -113,11 +115,18 @@
 #if defined(__clang__) && (__clang_major__ >= 3 || (__clang_major__ == 2 && __clang_minor__ >= 9))
 # define MOZ_DELETE            = delete
 #elif defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4))
-/*
- * g++ >= 4.4 supports deleted functions, but it requires -std=c++0x or
- * -std=gnu++0x, and for various reasons we can't use these yet.
- */
-# define MOZ_DELETE            /* = delete */
+ /*
+  * g++ >= 4.4 requires -std=c++0x or -std=gnu++0x to support deleted functions
+  * without warnings.  These modes are detectable by the experimental macro used
+  * below or, more standardly, by checking whether __cplusplus has a C++11 or
+  * greater value.  Current versions of g++ do not correctly set __cplusplus, so
+  * we check both for forward compatibility.
+  */
+# if defined(__GXX_EXPERIMENTAL_CXX0X__) || __cplusplus >= 201103L
+#  define MOZ_DELETE           = delete
+# else
+#  define MOZ_DELETE           /* = delete */
+# endif
 #else
 # define MOZ_DELETE            /* unknown C++11 deleted function support */
 #endif