Unify the two copies of template_util.h

This patch basically deletes webrtc/base/template_util.h (which is the
more outdated copy, although there are only cosmetical differences)
and moves webrtc/system_wrappers/source/template_util.h to take its
place.

The reunified header uses the rtc namespace like the old
webrtc/base/template_util.h, rather than the webrtc namespace like
webrtc/system_wrappers/source/template_util.h.

R=aluebs@webrtc.org, andrew@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/38579004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@8050 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/base/BUILD.gn

@@ -120,6 +120,7 @@ static_library("rtc_base_approved") {
     "stringencode.h",
     "stringutils.cc",
     "stringutils.h",
+    "template_util.h",
     "thread_annotations.h",
     "timeutils.cc",
     "timeutils.h",

webrtc/base/base.gyp

@@ -55,6 +55,7 @@
         'stringencode.h',
         'stringutils.cc',
         'stringutils.h',
+        'template_util.h',
         'thread_annotations.h',
         'timeutils.cc',
         'timeutils.h',

webrtc/base/template_util.h

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2011 The WebRTC Project Authors. All rights reserved.
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
@@ -8,6 +8,8 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
+// Borrowed from Chromium's src/base/template_util.h.
+
 #ifndef WEBRTC_BASE_TEMPLATE_UTIL_H_
 #define WEBRTC_BASE_TEMPLATE_UTIL_H_
 
@@ -15,7 +17,7 @@
 
 namespace rtc {
 
-// template definitions from tr1
+// Template definitions from tr1.
 
 template<class T, T v>
 struct integral_constant {

webrtc/system_wrappers/interface/scoped_ptr.h

@@ -107,7 +107,7 @@
 #include "webrtc/base/compile_assert.h"
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/base/move.h"
-#include "webrtc/system_wrappers/interface/template_util.h"
+#include "webrtc/base/template_util.h"
 #include "webrtc/typedefs.h"
 
 namespace webrtc {
@@ -133,7 +133,7 @@ struct DefaultDeleter {
     // cannot convert to T*.
     enum { T_must_be_complete = sizeof(T) };
     enum { U_must_be_complete = sizeof(U) };
-    COMPILE_ASSERT((webrtc::is_convertible<U*, T*>::value),
+    COMPILE_ASSERT((rtc::is_convertible<U*, T*>::value),
                    U_ptr_must_implicitly_convert_to_T_ptr);
   }
   inline void operator()(T* ptr) const {
@@ -183,12 +183,13 @@ namespace internal {
 template <typename T>
 struct ShouldAbortOnSelfReset {
   template <typename U>
-  static NoType Test(const typename U::AllowSelfReset*);
+  static rtc::internal::NoType Test(const typename U::AllowSelfReset*);
 
   template <typename U>
-  static YesType Test(...);
+  static rtc::internal::YesType Test(...);
 
-  static const bool value = sizeof(Test<T>(0)) == sizeof(YesType);
+  static const bool value =
+      sizeof(Test<T>(0)) == sizeof(rtc::internal::YesType);
 };
 
 // Minimal implementation of the core logic of scoped_ptr, suitable for
@@ -350,7 +351,7 @@ class scoped_ptr {
   template <typename U, typename V>
   scoped_ptr(scoped_ptr<U, V>&& other)
       : impl_(&other.impl_) {
-    COMPILE_ASSERT(!webrtc::is_array<U>::value, U_cannot_be_an_array);
+    COMPILE_ASSERT(!rtc::is_array<U>::value, U_cannot_be_an_array);
   }
 
   // operator=.  Allows assignment from a scoped_ptr rvalue for a convertible
@@ -365,7 +366,7 @@ class scoped_ptr {
   // scoped_ptr.
   template <typename U, typename V>
   scoped_ptr& operator=(scoped_ptr<U, V>&& rhs) {
-    COMPILE_ASSERT(!webrtc::is_array<U>::value, U_cannot_be_an_array);
+    COMPILE_ASSERT(!rtc::is_array<U>::value, U_cannot_be_an_array);
     impl_.TakeState(&rhs.impl_);
     return *this;
   }

webrtc/system_wrappers/interface/template_util.h

@@ -1,114 +0,0 @@
-/*
- *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-// Borrowed from Chromium's src/base/template_util.h.
-
-#ifndef WEBRTC_SYSTEM_WRAPPERS_INTERFACE_TEMPLATE_UTIL_H_
-#define WEBRTC_SYSTEM_WRAPPERS_INTERFACE_TEMPLATE_UTIL_H_
-
-#include <stddef.h>  // For size_t.
-
-namespace webrtc {
-
-// Template definitions from tr1.
-
-template<class T, T v>
-struct integral_constant {
-  static const T value = v;
-  typedef T value_type;
-  typedef integral_constant<T, v> type;
-};
-
-template <class T, T v> const T integral_constant<T, v>::value;
-
-typedef integral_constant<bool, true> true_type;
-typedef integral_constant<bool, false> false_type;
-
-template <class T> struct is_pointer : false_type {};
-template <class T> struct is_pointer<T*> : true_type {};
-
-template <class T, class U> struct is_same : public false_type {};
-template <class T> struct is_same<T, T> : true_type {};
-
-template<class> struct is_array : public false_type {};
-template<class T, size_t n> struct is_array<T[n]> : public true_type {};
-template<class T> struct is_array<T[]> : public true_type {};
-
-template <class T> struct is_non_const_reference : false_type {};
-template <class T> struct is_non_const_reference<T&> : true_type {};
-template <class T> struct is_non_const_reference<const T&> : false_type {};
-
-template <class T> struct is_void : false_type {};
-template <> struct is_void<void> : true_type {};
-
-namespace internal {
-
-// Types YesType and NoType are guaranteed such that sizeof(YesType) <
-// sizeof(NoType).
-typedef char YesType;
-
-struct NoType {
-  YesType dummy[2];
-};
-
-// This class is an implementation detail for is_convertible, and you
-// don't need to know how it works to use is_convertible. For those
-// who care: we declare two different functions, one whose argument is
-// of type To and one with a variadic argument list. We give them
-// return types of different size, so we can use sizeof to trick the
-// compiler into telling us which function it would have chosen if we
-// had called it with an argument of type From.  See Alexandrescu's
-// _Modern C++ Design_ for more details on this sort of trick.
-
-struct ConvertHelper {
-  template <typename To>
-  static YesType Test(To);
-
-  template <typename To>
-  static NoType Test(...);
-
-  template <typename From>
-  static From& Create();
-};
-
-// Used to determine if a type is a struct/union/class. Inspired by Boost's
-// is_class type_trait implementation.
-struct IsClassHelper {
-  template <typename C>
-  static YesType Test(void(C::*)(void));
-
-  template <typename C>
-  static NoType Test(...);
-};
-
-}  // namespace internal
-
-// Inherits from true_type if From is convertible to To, false_type otherwise.
-//
-// Note that if the type is convertible, this will be a true_type REGARDLESS
-// of whether or not the conversion would emit a warning.
-template <typename From, typename To>
-struct is_convertible
-    : integral_constant<bool,
-                        sizeof(internal::ConvertHelper::Test<To>(
-                                   internal::ConvertHelper::Create<From>())) ==
-                        sizeof(internal::YesType)> {
-};
-
-template <typename T>
-struct is_class
-    : integral_constant<bool,
-                        sizeof(internal::IsClassHelper::Test<T>(0)) ==
-                            sizeof(internal::YesType)> {
-};
-
-}  // namespace webrtc
-
-#endif  // WEBRTC_SYSTEM_WRAPPERS_INTERFACE_TEMPLATE_UTIL_H_