From 8b0acb2f4375e9ce9405a6a14008801ce96e0092 Mon Sep 17 00:00:00 2001
From: Benjamin Morgan <benjamin.morgan@bosch.com>
Date: Thu, 26 Oct 2023 16:41:36 +0200
Subject: [PATCH] engine: Replace boost::optional with std::optional

---
 engine/src/main_commands.hpp         |  3 +-
 engine/src/simulation.cpp            |  2 +-
 engine/src/simulation.hpp            |  2 +-
 engine/src/stack.hpp                 | 50 ++++++++++++++--------------
 engine/src/stack_factory.cpp         |  2 +-
 engine/src/utility/command.hpp       |  8 ++---
 engine/src/utility/state_machine.hpp |  7 ++--
 7 files changed, 36 insertions(+), 38 deletions(-)

diff --git a/engine/src/main_commands.hpp b/engine/src/main_commands.hpp
index e701055b4..f984eed6b 100644
--- a/engine/src/main_commands.hpp
+++ b/engine/src/main_commands.hpp
@@ -20,11 +20,10 @@
  * \see  main.cpp
  */
 
+#include <optional>
 #include <string>
 #include <vector>
 
-#include <boost/optional.hpp>  // for optional<>
-
 #include "lua_setup.hpp"
 #include "stack_factory.hpp"
 
diff --git a/engine/src/simulation.cpp b/engine/src/simulation.cpp
index c82e00501..a8511026f 100644
--- a/engine/src/simulation.cpp
+++ b/engine/src/simulation.cpp
@@ -150,7 +150,7 @@ class SimulationMachine
       try {
         // Handle interrupts that have been inserted via push_interrupt.
         // Only one interrupt is stored.
-        boost::optional<StateId> interrupt;
+        std::optional<StateId> interrupt;
         while ((interrupt = pop_interrupt())) {
           id = handle_interrupt(id, *interrupt, ctx);
         }
diff --git a/engine/src/simulation.hpp b/engine/src/simulation.hpp
index 595304ef9..1399bb6f0 100644
--- a/engine/src/simulation.hpp
+++ b/engine/src/simulation.hpp
@@ -49,7 +49,7 @@ struct SimulationResult {
   cloe::Json signals;  // dump of all signals in DataBroker right before the simulation started
   std::vector<std::string>
       signals_autocompletion;  // pseudo lua file used for vscode autocompletion
-  boost::optional<boost::filesystem::path> output_dir;
+  std::optional<boost::filesystem::path> output_dir;
 
  public:
   /**
diff --git a/engine/src/stack.hpp b/engine/src/stack.hpp
index fc73182bb..b8e918aa3 100644
--- a/engine/src/stack.hpp
+++ b/engine/src/stack.hpp
@@ -29,9 +29,9 @@
 #include <string>   // for string
 #include <utility>  // for move
 #include <vector>   // for vector<>
+#include <optional> // for optional<>
 
 #include <boost/filesystem/path.hpp>        // for path
-#include <boost/optional.hpp>               // for optional<>
 #include <fable/schema/boost_optional.hpp>  // for Optional<>
 #include <fable/schema/boost_path.hpp>      // for Path
 #include <fable/schema/custom.hpp>          // for CustomDeserializer
@@ -140,8 +140,8 @@ using IncludesSchema = schema::Vector<IncludeConf, IncludeSchema>;
  */
 struct LoggingConf : public Confable {
   std::string name;
-  boost::optional<std::string> pattern;
-  boost::optional<LogLevel> level;
+  std::optional<std::string> pattern;
+  std::optional<LogLevel> level;
 
  public:  // Special
   void apply() const;
@@ -205,20 +205,20 @@ struct PluginConf : public PersistentConfable {
   boost::filesystem::path plugin_path{};
 
   /** Name to give plugin if path is to a single file. */
-  boost::optional<std::string> plugin_name{};
+  std::optional<std::string> plugin_name{};
 
   /** Prefix for plugin name(s). */
-  boost::optional<std::string> plugin_prefix{};
+  std::optional<std::string> plugin_prefix{};
 
   /** Do not fail if path does not exist. */
-  boost::optional<bool> ignore_missing{};
+  std::optional<bool> ignore_missing{};
 
   /**
    * Do not fail if path exists but plugin cannot be loaded.
    * This is especially useful if trying to load from several directories,
    * such as /usr/lib/cloe/plugins.
    */
-  boost::optional<bool> ignore_failure{};
+  std::optional<bool> ignore_failure{};
 
   /**
    * If a plugin with the same name exists, replace it with this one.
@@ -226,7 +226,7 @@ struct PluginConf : public PersistentConfable {
    * This is dependent on the order of plugin loading, which is determined by
    * the order of configuration files.
    */
-  boost::optional<bool> allow_clobber{};
+  std::optional<bool> allow_clobber{};
 
  public:  // Constructors
   PluginConf() = default;
@@ -309,14 +309,14 @@ struct EngineConf : public Confable {
   bool triggers_ignore_source{false};
 
   // Output:
-  boost::optional<boost::filesystem::path> registry_path{CLOE_DATA_HOME "/registry"};
-  boost::optional<boost::filesystem::path> output_path{"${CLOE_SIMULATION_UUID}"};
-  boost::optional<boost::filesystem::path> output_file_config{"config.json"};
-  boost::optional<boost::filesystem::path> output_file_result{"result.json"};
-  boost::optional<boost::filesystem::path> output_file_triggers{"triggers.json"};
-  boost::optional<boost::filesystem::path> output_file_signals{"signals.json"};
-  boost::optional<boost::filesystem::path> output_file_signals_autocompletion;
-  boost::optional<boost::filesystem::path> output_file_data_stream;
+  std::optional<boost::filesystem::path> registry_path{CLOE_DATA_HOME "/registry"};
+  std::optional<boost::filesystem::path> output_path{"${CLOE_SIMULATION_UUID}"};
+  std::optional<boost::filesystem::path> output_file_config{"config.json"};
+  std::optional<boost::filesystem::path> output_file_result{"result.json"};
+  std::optional<boost::filesystem::path> output_file_triggers{"triggers.json"};
+  std::optional<boost::filesystem::path> output_file_signals{"signals.json"};
+  std::optional<boost::filesystem::path> output_file_signals_autocompletion;
+  std::optional<boost::filesystem::path> output_file_data_stream;
   bool output_clobber_files{true};
 
   /**
@@ -371,7 +371,7 @@ struct EngineConf : public Confable {
    * The states with an asterisk are given defaults that are not affected by
    * the default timeout as these typically take longer due to I/O operations.
    */
-  std::map<std::string, boost::optional<std::chrono::milliseconds>> watchdog_state_timeouts{
+  std::map<std::string, std::optional<std::chrono::milliseconds>> watchdog_state_timeouts{
       {"CONNECT", std::chrono::milliseconds{300'000}},
       {"ABORT", std::chrono::milliseconds{90'000}},
       {"STOP", std::chrono::milliseconds{300'000}},
@@ -453,8 +453,8 @@ using EngineSchema = schema_type<EngineConf>::type;
  * good idea!
  */
 struct DefaultConf : public Confable {
-  boost::optional<std::string> name;
-  boost::optional<std::string> binding;
+  std::optional<std::string> name;
+  std::optional<std::string> binding;
   Conf args;
 
  public:  // Confable Overrides
@@ -495,7 +495,7 @@ class FactoryPlugin : public fable::schema::FactoryPointerless<C> {
  */
 struct SimulatorConf : public Confable {
   const std::string binding;
-  boost::optional<std::string> name;
+  std::optional<std::string> name;
   std::shared_ptr<SimulatorFactory> factory;
   Conf args;
 
@@ -529,7 +529,7 @@ class SimulatorSchema : public FactoryPlugin<SimulatorConf, SimulatorFactory> {
  */
 struct ControllerConf : public Confable {
   const std::string binding;
-  boost::optional<std::string> name;
+  std::optional<std::string> name;
   std::string vehicle;
   std::shared_ptr<ControllerFactory> factory;
   Conf args;
@@ -615,7 +615,7 @@ struct FromSimulator : public Confable {
 
 struct ComponentConf : public Confable {
   const std::string binding;
-  boost::optional<std::string> name;
+  std::optional<std::string> name;
   std::vector<std::string> from;
   std::shared_ptr<ComponentFactory> factory;
   Conf args;
@@ -780,7 +780,7 @@ class VehicleSchema : public fable::schema::Base<VehicleSchema> {
 // --------------------------------------------------------------------------------------------- //
 
 struct TriggerConf : public PersistentConfable {
-  boost::optional<std::string> label{boost::none};
+  std::optional<std::string> label{};
   Source source{Source::FILESYSTEM};
   Conf action{};
   Conf event{};
@@ -823,7 +823,7 @@ struct SimulationConf : public Confable {
   /**
    * Optional namespace for simulation events and actions.
    */
-  boost::optional<std::string> name{boost::none};
+  std::optional<std::string> name{};
 
   /**
    * Nominal model time step.
@@ -887,7 +887,7 @@ using ConfReader = std::function<Conf(const std::string&)>;
 class Stack : public Confable {
  private:  // Constants (1)
   std::vector<std::string> reserved_ids_;
-  boost::optional<std::string> schema_ref_;
+  std::optional<std::string> schema_ref_;
 
  public:  // Configuration (13)
   std::string version;
diff --git a/engine/src/stack_factory.cpp b/engine/src/stack_factory.cpp
index 6d5af1c39..a13ee1c31 100644
--- a/engine/src/stack_factory.cpp
+++ b/engine/src/stack_factory.cpp
@@ -106,7 +106,7 @@ Stack new_stack(const StackOptions& opt) {
 
   // Interpolate known variables, if requested.
   if (opt.interpolate_vars) {
-    auto interpolate_path = [&opt](boost::optional<boost::filesystem::path>& p) {
+    auto interpolate_path = [&opt](std::optional<boost::filesystem::path>& p) {
       p = fable::interpolate_vars(p->native(), opt.environment.get());
     };
     interpolate_path(s.engine.registry_path);
diff --git a/engine/src/utility/command.hpp b/engine/src/utility/command.hpp
index 41789aca4..dde4bddbd 100644
--- a/engine/src/utility/command.hpp
+++ b/engine/src/utility/command.hpp
@@ -24,11 +24,11 @@
 
 #pragma once
 
+#include <optional>      // for optional<>
 #include <string>        // for string
 #include <system_error>  // for system_error
 #include <vector>        // for vector<>
 
-#include <boost/optional.hpp>        // for optional<>
 #include <boost/process/child.hpp>   // for child
 #include <cloe/core.hpp>             // for Logger, Json, Conf, ...
 #include <cloe/trigger.hpp>          // for Action, ActionFactory, ...
@@ -39,9 +39,9 @@ namespace engine {
 struct CommandResult {
   std::string name;
   std::string command;
-  boost::optional<boost::process::child> child;
-  boost::optional<int> exit_code;
-  boost::optional<std::runtime_error> error;
+  std::optional<boost::process::child> child;
+  std::optional<int> exit_code;
+  std::optional<std::runtime_error> error;
   std::vector<std::string> output;
 };
 
diff --git a/engine/src/utility/state_machine.hpp b/engine/src/utility/state_machine.hpp
index c33b45fab..c59c68159 100644
--- a/engine/src/utility/state_machine.hpp
+++ b/engine/src/utility/state_machine.hpp
@@ -26,10 +26,9 @@
 #include <map>               // for map<>
 #include <memory>            // for shared_ptr<>
 #include <mutex>             // for mutex, lock_guard<>
+#include <optional>          // for optional<>
 #include <utility>           // for move
 
-#include <boost/optional.hpp>  // for optional<>
-
 #include <cloe/core.hpp>                // for Json
 #include <cloe/utility/statistics.hpp>  // for Accumulator
 #include <cloe/utility/timer.hpp>       // for DurationTimer<>
@@ -195,10 +194,10 @@ class StateMachine {
     interrupt_ = id;
   }
 
-  boost::optional<StateId> pop_interrupt() {
+  std::optional<StateId> pop_interrupt() {
     std::lock_guard<std::mutex> guard(interrupt_mtx_);
     if (interrupt_ == nullptr) {
-      return boost::none;
+      return std::nullopt;
     } else {
       auto tmp = interrupt_;
       interrupt_ = nullptr;