Use Boost.Optional instead of custom optional monad implementation.

This switches out the `<variant/optional.hpp>` implementation of the
optional monad to the one from Boost.

The following trick makes sure we keep compile times down:

- use `<boost/optional/optional_fwd.hpp>` to forward declare the
  optional type in header, then include the full blown optional header
  only in the implementation file.

- do the same for the files we touch, e.g. forward declare osmium types,
  allowing us to remove the osmium header dependency from our headers:

      `namespace osmium { class Relation; }

  and then include the appropriate osmium headers in the implementation
  file only. We should do this globally...

References:

- http://www.boost.org/doc/libs/1_59_0/libs/optional/doc/html/index.html
- https://github.com/osmcode/libosmium/issues/123

extractor/extractor.cpp

@@ -45,6 +45,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <boost/filesystem.hpp>
 #include <boost/filesystem/fstream.hpp>
+#include <boost/optional/optional.hpp>
 
 #include <luabind/luabind.hpp>
 
@@ -53,8 +54,6 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <tbb/parallel_for.h>
 #include <tbb/task_scheduler_init.h>
 
-#include <variant/optional.hpp>
-
 #include <cstdlib>
 
 #include <algorithm>
@@ -151,8 +150,7 @@ int extractor::run()
         // initialize vectors holding parsed objects
         tbb::concurrent_vector<std::pair<std::size_t, ExtractionNode>> resulting_nodes;
         tbb::concurrent_vector<std::pair<std::size_t, ExtractionWay>> resulting_ways;
-        tbb::concurrent_vector<mapbox::util::optional<InputRestrictionContainer>>
-            resulting_restrictions;
+        tbb::concurrent_vector<boost::optional<InputRestrictionContainer>> resulting_restrictions;
 
         // setup restriction parser
         const RestrictionParser restriction_parser(scripting_environment.get_lua_state());

extractor/extractor_callbacks.cpp

@@ -35,6 +35,10 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include "../util/container.hpp"
 #include "../util/simple_logger.hpp"
 
+#include <boost/optional/optional.hpp>
+
+#include <osmium/osm.hpp>
+
 #include <osrm/coordinate.hpp>
 
 #include <limits>
@@ -65,7 +69,7 @@ void ExtractorCallbacks::ProcessNode(const osmium::Node &input_node,
 }
 
 void ExtractorCallbacks::ProcessRestriction(
-    const mapbox::util::optional<InputRestrictionContainer> &restriction)
+    const boost::optional<InputRestrictionContainer> &restriction)
 {
     if (restriction)
     {
@@ -140,8 +144,8 @@ void ExtractorCallbacks::ProcessWay(const osmium::Way &input_way, const Extracti
         }
     }
 
-    if (forward_weight_data.type == InternalExtractorEdge::WeightType::INVALID
-     && backward_weight_data.type == InternalExtractorEdge::WeightType::INVALID)
+    if (forward_weight_data.type == InternalExtractorEdge::WeightType::INVALID &&
+        backward_weight_data.type == InternalExtractorEdge::WeightType::INVALID)
     {
         SimpleLogger().Write(logDEBUG) << "found way with bogus speed, id: " << input_way.id();
         return;
@@ -169,7 +173,10 @@ void ExtractorCallbacks::ProcessWay(const osmium::Way &input_way, const Extracti
 
     std::transform(input_way.nodes().begin(), input_way.nodes().end(),
                    std::back_inserter(external_memory.used_node_id_list),
-                   [](const osmium::NodeRef& ref) { return ref.ref(); });
+                   [](const osmium::NodeRef &ref)
+                   {
+                       return ref.ref();
+                   });
 
     const bool is_opposite_way = TRAVEL_MODE_INACCESSIBLE == parsed_way.forward_travel_mode;
 
@@ -182,53 +189,51 @@ void ExtractorCallbacks::ProcessWay(const osmium::Way &input_way, const Extracti
                             [&](const osmium::NodeRef &first_node, const osmium::NodeRef &last_node)
                             {
                                 external_memory.all_edges_list.push_back(InternalExtractorEdge(
-                                    first_node.ref(), last_node.ref(), name_id, backward_weight_data,
-                                    true, false, parsed_way.roundabout, parsed_way.is_access_restricted,
+                                    first_node.ref(), last_node.ref(), name_id,
+                                    backward_weight_data, true, false, parsed_way.roundabout,
+                                    parsed_way.is_access_restricted,
                                     parsed_way.backward_travel_mode, false));
                             });
 
         external_memory.way_start_end_id_list.push_back(
-            {
-                static_cast<EdgeID>(input_way.id()),
-                static_cast<NodeID>(input_way.nodes().back().ref()),
-                static_cast<NodeID>(input_way.nodes()[input_way.nodes().size() - 2].ref()),
-                static_cast<NodeID>(input_way.nodes()[1].ref()),
-                static_cast<NodeID>(input_way.nodes()[0].ref())
-             }
-        );
+            {static_cast<EdgeID>(input_way.id()),
+             static_cast<NodeID>(input_way.nodes().back().ref()),
+             static_cast<NodeID>(input_way.nodes()[input_way.nodes().size() - 2].ref()),
+             static_cast<NodeID>(input_way.nodes()[1].ref()),
+             static_cast<NodeID>(input_way.nodes()[0].ref())});
     }
     else
     {
-        const bool forward_only = split_edge || TRAVEL_MODE_INACCESSIBLE == parsed_way.backward_travel_mode;
+        const bool forward_only =
+            split_edge || TRAVEL_MODE_INACCESSIBLE == parsed_way.backward_travel_mode;
         osrm::for_each_pair(input_way.nodes().cbegin(), input_way.nodes().cend(),
                             [&](const osmium::NodeRef &first_node, const osmium::NodeRef &last_node)
                             {
                                 external_memory.all_edges_list.push_back(InternalExtractorEdge(
                                     first_node.ref(), last_node.ref(), name_id, forward_weight_data,
-                                    true, !forward_only, parsed_way.roundabout, parsed_way.is_access_restricted,
-                                    parsed_way.forward_travel_mode, split_edge));
+                                    true, !forward_only, parsed_way.roundabout,
+                                    parsed_way.is_access_restricted, parsed_way.forward_travel_mode,
+                                    split_edge));
                             });
         if (split_edge)
         {
             BOOST_ASSERT(parsed_way.backward_travel_mode != TRAVEL_MODE_INACCESSIBLE);
-            osrm::for_each_pair(input_way.nodes().cbegin(), input_way.nodes().cend(),
-                                [&](const osmium::NodeRef &first_node, const osmium::NodeRef &last_node)
-                                {
-                                    external_memory.all_edges_list.push_back(InternalExtractorEdge(
-                                        first_node.ref(), last_node.ref(), name_id, backward_weight_data,
-                                        false, true, parsed_way.roundabout, parsed_way.is_access_restricted,
-                                        parsed_way.backward_travel_mode, true));
-                                });
+            osrm::for_each_pair(
+                input_way.nodes().cbegin(), input_way.nodes().cend(),
+                [&](const osmium::NodeRef &first_node, const osmium::NodeRef &last_node)
+                {
+                    external_memory.all_edges_list.push_back(InternalExtractorEdge(
+                        first_node.ref(), last_node.ref(), name_id, backward_weight_data, false,
+                        true, parsed_way.roundabout, parsed_way.is_access_restricted,
+                        parsed_way.backward_travel_mode, true));
+                });
         }
 
         external_memory.way_start_end_id_list.push_back(
-            {
-                static_cast<EdgeID>(input_way.id()),
-                static_cast<NodeID>(input_way.nodes().back().ref()),
-                static_cast<NodeID>(input_way.nodes()[input_way.nodes().size() - 2].ref()),
-                static_cast<NodeID>(input_way.nodes()[1].ref()),
-                static_cast<NodeID>(input_way.nodes()[0].ref())
-             }
-        );
+            {static_cast<EdgeID>(input_way.id()),
+             static_cast<NodeID>(input_way.nodes().back().ref()),
+             static_cast<NodeID>(input_way.nodes()[input_way.nodes().size() - 2].ref()),
+             static_cast<NodeID>(input_way.nodes()[1].ref()),
+             static_cast<NodeID>(input_way.nodes()[0].ref())});
     }
 }

extractor/extractor_callbacks.hpp

@@ -28,12 +28,8 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef EXTRACTOR_CALLBACKS_HPP
 #define EXTRACTOR_CALLBACKS_HPP
 
-#include "extraction_way.hpp"
 #include "../typedefs.h"
-
-#include <osmium/osm.hpp>
-
-#include <variant/optional.hpp>
+#include <boost/optional/optional_fwd.hpp>
 
 #include <string>
 #include <unordered_map>
@@ -42,6 +38,12 @@ struct ExternalMemoryNode;
 class ExtractionContainers;
 struct InputRestrictionContainer;
 struct ExtractionNode;
+struct ExtractionWay;
+namespace osmium
+{
+class Node;
+class Way;
+}
 
 /**
  * This class is uses by the extractor with the results of the
@@ -66,7 +68,7 @@ class ExtractorCallbacks
     void ProcessNode(const osmium::Node &current_node, const ExtractionNode &result_node);
 
     // warning: caller needs to take care of synchronization!
-    void ProcessRestriction(const mapbox::util::optional<InputRestrictionContainer> &restriction);
+    void ProcessRestriction(const boost::optional<InputRestrictionContainer> &restriction);
 
     // warning: caller needs to take care of synchronization!
     void ProcessWay(const osmium::Way &current_way, const ExtractionWay &result_way);

extractor/restriction_parser.cpp

@@ -38,17 +38,20 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <boost/algorithm/string/predicate.hpp>
 #include <boost/ref.hpp>
 #include <boost/regex.hpp>
+#include <boost/optional/optional.hpp>
+
+#include <osmium/osm.hpp>
+#include <osmium/tags/regex_filter.hpp>
 
 #include <algorithm>
+#include <iterator>
 
 namespace
 {
 int lua_error_callback(lua_State *lua_state)
 {
     std::string error_msg = lua_tostring(lua_state, -1);
-    std::ostringstream error_stream;
-    error_stream << error_msg;
-    throw osrm::exception("ERROR occured in profile script:\n" + error_stream.str());
+    throw osrm::exception("ERROR occured in profile script:\n" + error_msg);
 }
 }
 
@@ -104,18 +107,18 @@ void RestrictionParser::ReadRestrictionExceptions(lua_State *lua_state)
 
 /**
  * Tries to parse an relation as turn restriction. This can fail for a number of
- * reasons, this the return type is a mapbox::util::optional<>.
+ * reasons, this the return type is a boost::optional<T>.
  *
  * Some restrictions can also be ignored: See the ```get_exceptions``` function
  * in the corresponding profile.
  */
-mapbox::util::optional<InputRestrictionContainer>
+boost::optional<InputRestrictionContainer>
 RestrictionParser::TryParse(const osmium::Relation &relation) const
 {
     // return if turn restrictions should be ignored
     if (!use_turn_restrictions)
     {
-        return mapbox::util::optional<InputRestrictionContainer>();
+        return {};
     }
 
     osmium::tags::KeyPrefixFilter filter(false);
@@ -129,14 +132,14 @@ RestrictionParser::TryParse(const osmium::Relation &relation) const
     // if it's a restriction, continue;
     if (std::distance(fi_begin, fi_end) == 0)
     {
-        return mapbox::util::optional<InputRestrictionContainer>();
+        return {};
     }
 
     // check if the restriction should be ignored
     const char *except = relation.get_value_by_key("except");
     if (except != nullptr && ShouldIgnoreRestriction(except))
     {
-        return mapbox::util::optional<InputRestrictionContainer>();
+        return {};
     }
 
     bool is_only_restriction = false;
@@ -164,7 +167,7 @@ RestrictionParser::TryParse(const osmium::Relation &relation) const
 
             if (!is_actually_restricted)
             {
-                return mapbox::util::optional<InputRestrictionContainer>();
+                return {};
             }
         }
     }
@@ -218,7 +221,7 @@ RestrictionParser::TryParse(const osmium::Relation &relation) const
             break;
         }
     }
-    return mapbox::util::optional<InputRestrictionContainer>(restriction_container);
+    return boost::make_optional(std::move(restriction_container));
 }
 
 bool RestrictionParser::ShouldIgnoreRestriction(const std::string &except_tag_string) const

extractor/restriction_parser.hpp

@@ -30,16 +30,16 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include "../data_structures/restriction.hpp"
 
-#include <osmium/osm.hpp>
-#include <osmium/tags/regex_filter.hpp>
-
-#include <variant/optional.hpp>
+#include <boost/optional/optional_fwd.hpp>
 
 #include <string>
 #include <vector>
 
 struct lua_State;
-class ScriptingEnvironment;
+namespace osmium
+{
+class Relation;
+}
 
 /**
  * Parses the relations that represents turn restrictions.
@@ -63,8 +63,7 @@ class RestrictionParser
 {
   public:
     RestrictionParser(lua_State *lua_state);
-    mapbox::util::optional<InputRestrictionContainer>
-    TryParse(const osmium::Relation &relation) const;
+    boost::optional<InputRestrictionContainer> TryParse(const osmium::Relation &relation) const;
 
   private:
     void ReadUseRestrictionsSetting(lua_State *lua_state);

routing_algorithms/map_matching.hpp

@@ -35,11 +35,14 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include "../util/json_logger.hpp"
 #include "../util/matching_debug_info.hpp"
 
-#include <variant/variant.hpp>
+#include <cstddef>
 
 #include <algorithm>
+#include <deque>
 #include <iomanip>
 #include <numeric>
+#include <utility>
+#include <vector>
 
 namespace osrm
 {