1 files changed, 128 insertions, 0 deletions
diff --git a/cmdline/detail/cmdline_parser_detail.h b/cmdline/detail/cmdline_parser_detail.h
new file mode 100644
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+++ b/cmdline/detail/cmdline_parser_detail.h
@@ -0,0 +1,128 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_CMDLINE_DETAIL_CMDLINE_PARSER_DETAIL_H_
+#define ART_CMDLINE_DETAIL_CMDLINE_PARSER_DETAIL_H_
+
+#include <string>
+#include <sstream>
+#include <vector>
+
+namespace art {
+  // Implementation details for some template querying. Don't look inside if you hate templates.
+  namespace detail {
+    template <typename T>
+    typename std::remove_reference<T>::type& FakeReference();
+
+    // SupportsInsertionOperator<T, TStream>::value will evaluate to a boolean,
+    // whose value is true if the TStream class supports the << operator against T,
+    // and false otherwise.
+    template <typename T2, typename TStream2 = std::ostream>
+    struct SupportsInsertionOperator {
+     private:
+      template <typename TStream, typename T>
+      static std::true_type InsertionOperatorTest(TStream& os, const T& value,
+                                                  std::remove_reference<decltype(os << value)>* = 0); // NOLINT [whitespace/operators] [3]
+
+      template <typename TStream, typename ... T>
+      static std::false_type InsertionOperatorTest(TStream& os, const T& ... args);
+
+     public:
+      static constexpr bool value =
+          decltype(InsertionOperatorTest(FakeReference<TStream2>(), std::declval<T2>()))::value;
+    };
+
+    template <typename TLeft, typename TRight = TLeft, bool IsFloatingPoint = false>
+    struct SupportsEqualityOperatorImpl;
+
+    template <typename TLeft, typename TRight>
+    struct SupportsEqualityOperatorImpl<TLeft, TRight, false> {
+     private:
+      template <typename TL, typename TR>
+      static std::true_type EqualityOperatorTest(const TL& left, const TR& right,
+                                                 std::remove_reference<decltype(left == right)>* = 0); // NOLINT [whitespace/operators] [3]
+
+      template <typename TL, typename ... T>
+      static std::false_type EqualityOperatorTest(const TL& left, const T& ... args);
+
+     public:
+      static constexpr bool value =
+          decltype(EqualityOperatorTest(std::declval<TLeft>(), std::declval<TRight>()))::value;
+    };
+
+    // Partial specialization when TLeft/TRight are both floating points.
+    // This is a work-around because decltype(floatvar1 == floatvar2)
+    // will not compile with clang:
+    // error: comparing floating point with == or != is unsafe [-Werror,-Wfloat-equal]
+    template <typename TLeft, typename TRight>
+    struct SupportsEqualityOperatorImpl<TLeft, TRight, true> {
+      static constexpr bool value = true;
+    };
+
+    // SupportsEqualityOperatorImpl<T1, T2>::value will evaluate to a boolean,
+    // whose value is true if T1 can be compared against T2 with ==,
+    // and false otherwise.
+    template <typename TLeft, typename TRight = TLeft>
+    struct SupportsEqualityOperator :
+        SupportsEqualityOperatorImpl<TLeft, TRight,
+                                     std::is_floating_point<TLeft>::value
+                                     && std::is_floating_point<TRight>::value> {
+    };
+
+    // Convert any kind of type to an std::string, even if there's no
+    // serialization support for it. Unknown types get converted to an
+    // an arbitrary value.
+    //
+    // Meant for printing user-visible errors or unit test failures only.
+    template <typename T>
+    std::string ToStringAny(const T& value,
+                            typename std::enable_if<
+                                SupportsInsertionOperator<T>::value>::type* = 0) {
+      std::stringstream stream;
+      stream << value;
+      return stream.str();
+    }
+
+    template <typename T>
+    std::string ToStringAny(const std::vector<T> value,
+                            typename std::enable_if<
+                                SupportsInsertionOperator<T>::value>::type* = 0) {
+      std::stringstream stream;
+      stream << "vector{";
+
+      for (size_t i = 0; i < value.size(); ++i) {
+        stream << ToStringAny(value[i]);
+
+        if (i != value.size() - 1) {
+          stream << ',';
+        }
+      }
+
+      stream << "}";
+      return stream.str();
+    }
+
+    template <typename T>
+    std::string ToStringAny(const T&,
+                            typename std::enable_if<
+                                !SupportsInsertionOperator<T>::value>::type* = 0
+    ) {
+      return std::string("(unknown type [no operator<< implemented] for )");
+    }
+  }  // namespace detail  // NOLINT [readability/namespace] [5]
+}  // namespace art
+
+#endif  // ART_CMDLINE_DETAIL_CMDLINE_PARSER_DETAIL_H_