util: remove ndn::variant, use std::variant directly

Change-Id: I374095f0f391454f3340bbf36785ccbebea2773a

COPYING.md

@@ -18,9 +18,6 @@ ndn-cxx relies on third-party software, licensed under the following licenses:
 - span-lite by Martin Moene is licensed under the
   [Boost Software License 1.0](https://github.com/martinmoene/span-lite/blob/master/LICENSE.txt)
 
-- variant-lite by Martin Moene is licensed under the
-  [Boost Software License 1.0](https://github.com/martinmoene/variant-lite/blob/master/LICENSE.txt)
-
 - SQLite is in the [public domain](https://www.sqlite.org/copyright.html)
 
 - The waf build system is licensed under the terms of the

ndn-cxx/key-locator.cpp

@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2022 Regents of the University of California.
+ * Copyright (c) 2013-2023 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -58,7 +58,7 @@ KeyLocator::wireEncode(EncodingImpl<TAG>& encoder) const
   size_t totalLength = 0;
 
   auto visitor = boost::hana::overload(
-    []  (monostate)           {}, // nothing to encode, TLV-VALUE is empty
+    []  (std::monostate)      {}, // nothing to encode, TLV-VALUE is empty
     [&] (const Name& name)    { totalLength += name.wireEncode(encoder); },
     [&] (const Block& digest) { totalLength += prependBlock(encoder, digest); },
     []  (uint32_t type)       { NDN_THROW(Error("Unsupported KeyLocator type " + to_string(type))); });
@@ -126,7 +126,7 @@ KeyLocator::getType() const
   case 2:
     return tlv::KeyDigest;
   case 3:
-    return get<uint32_t>(m_locator);
+    return std::get<uint32_t>(m_locator);
   default:
     NDN_CXX_UNREACHABLE;
   }
@@ -135,7 +135,7 @@ KeyLocator::getType() const
 KeyLocator&
 KeyLocator::clear()
 {
-  m_locator = monostate{};
+  m_locator = std::monostate{};
   m_wire.reset();
   return *this;
 }
@@ -144,9 +144,9 @@ const Name&
 KeyLocator::getName() const
 {
   try {
-    return get<Name>(m_locator);
+    return std::get<Name>(m_locator);
   }
-  catch (const bad_variant_access&) {
+  catch (const std::bad_variant_access&) {
     NDN_THROW(Error("KeyLocator does not contain a Name"));
   }
 }
@@ -163,9 +163,9 @@ const Block&
 KeyLocator::getKeyDigest() const
 {
   try {
-    return get<Block>(m_locator);
+    return std::get<Block>(m_locator);
   }
-  catch (const bad_variant_access&) {
+  catch (const std::bad_variant_access&) {
     NDN_THROW(Error("KeyLocator does not contain a KeyDigest"));
   }
 }
@@ -194,7 +194,7 @@ std::ostream&
 operator<<(std::ostream& os, const KeyLocator& keyLocator)
 {
   auto visitor = boost::hana::overload(
-    [&] (monostate) {
+    [&] (std::monostate) {
       os << "None";
     },
     [&] (const Name& name) {

ndn-cxx/key-locator.hpp

@@ -23,7 +23,8 @@
 #define NDN_CXX_KEY_LOCATOR_HPP
 
 #include "ndn-cxx/name.hpp"
-#include "ndn-cxx/util/variant.hpp"
+
+#include <variant>
 
 namespace ndn {
 
@@ -74,7 +75,7 @@ public: // attributes
   [[nodiscard]] bool
   empty() const
   {
-    return holds_alternative<monostate>(m_locator);
+    return std::holds_alternative<std::monostate>(m_locator);
   }
 
   uint32_t
@@ -144,7 +145,7 @@ private:
   // - Name is used when the nested TLV contains a name
   // - Block is used when the nested TLV is a KeyDigest
   // - in all other (unsupported) cases the nested TLV type is stored as uint32_t
-  variant<monostate, Name, Block, uint32_t> m_locator;
+  std::variant<std::monostate, Name, Block, uint32_t> m_locator;
 
   mutable Block m_wire;
 

ndn-cxx/util/variant.hpp

@@ -1,51 +0,0 @@
-/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/*
- * Copyright (c) 2013-2021 Regents of the University of California.
- *
- * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
- *
- * ndn-cxx library is free software: you can redistribute it and/or modify it under the
- * terms of the GNU Lesser General Public License as published by the Free Software
- * Foundation, either version 3 of the License, or (at your option) any later version.
- *
- * ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
- * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
- * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
- *
- * You should have received copies of the GNU General Public License and GNU Lesser
- * General Public License along with ndn-cxx, e.g., in COPYING.md file.  If not, see
- * <http://www.gnu.org/licenses/>.
- *
- * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
- */
-
-#ifndef NDN_CXX_UTIL_VARIANT_HPP
-#define NDN_CXX_UTIL_VARIANT_HPP
-
-#define variant_CONFIG_SELECT_VARIANT variant_VARIANT_NONSTD
-#define variant_CONFIG_OMIT_VARIANT_SIZE_V_MACRO 1
-#define variant_CONFIG_OMIT_VARIANT_ALTERNATIVE_T_MACRO 1
-#include "ndn-cxx/detail/nonstd/variant-lite.hpp"
-
-namespace ndn {
-
-using ::nonstd::variant;
-using ::nonstd::monostate;
-using ::nonstd::bad_variant_access;
-using ::nonstd::variant_npos;
-using ::nonstd::variant_size;
-using ::nonstd::variant_size_v;
-using ::nonstd::variant_alternative;
-using ::nonstd::variant_alternative_t;
-
-using ::nonstd::visit;
-using ::nonstd::holds_alternative;
-using ::nonstd::get;
-using ::nonstd::get_if;
-
-using ::nonstd::in_place;
-using ::nonstd::in_place_t;
-
-} // namespace ndn
-
-#endif // NDN_CXX_UTIL_VARIANT_HPP