Add base::get to support rvalue-reference tuple

base/tuple_unittest.cc

 // Copyright (c) 2006-2008 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 "base/tuple.h"
 
 #include "base/compiler_specific.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace base {
@@ skipping 96 matching lines @@
   EXPECT_EQ(1, CopyLogger::TimesCopied);
 
   // Now they should be different, since the function call will make a copy.
   res = false;
   DispatchToFunction(&SomeLoggerMethCopy, tuple);
   EXPECT_FALSE(res);
   EXPECT_EQ(3, CopyLogger::TimesConstructed);
   EXPECT_EQ(2, CopyLogger::TimesCopied);
 }
 
+TEST(TupleTest, Get) {
+  int i = 1;
+  int j = 2;
+  std::tuple<int, int&, int&&> t(3, i, std::move(j));
+  EXPECT_TRUE((std::is_same<int&, decltype(base::get<0>(t))>::value));
+  EXPECT_TRUE((std::is_same<int&, decltype(base::get<1>(t))>::value));
+  EXPECT_TRUE((std::is_same<int&, decltype(base::get<2>(t))>::value));
+
+  EXPECT_TRUE((std::is_same<int&&,
+               decltype(base::get<0>(std::move(t)))>::value));
+  EXPECT_TRUE((std::is_same<int&,
+               decltype(base::get<1>(std::move(t)))>::value));
+  EXPECT_TRUE((std::is_same<int&&,
+               decltype(base::get<2>(std::move(t)))>::value));
+}
+
 }  // namespace base