Use std::optional if available.

Currently, SDK requires C++11 minimum.
So, boost::optional type is used for optional values.
For C++17 and above more convenient is to use std::optional instead.
The task NLAM-23 is about making this type configurable.
This PR is a first part of the task: olp-cpp-sdk-core.

Relates-To: NLAM-23
Signed-off-by: sopov <[email protected]>

Author: asopov-here

external/CMakeLists.txt

@@ -97,7 +97,7 @@ if(OLP_SDK_ENABLE_DEFAULT_CACHE_LMDB)
     endif()
 endif()
 
-find_package(Boost QUIET)
+find_package(Boost 1.82.0 QUIET)
 if(NOT TARGET Boost AND NOT Boost_FOUND)
     add_subdirectory(boost)
     set(BOOST_ROOT ${EXTERNAL_BOOST_ROOT} PARENT_SCOPE)

olp-cpp-sdk-core/CMakeLists.txt

@@ -131,6 +131,7 @@ set(OLP_SDK_PORTING_HEADERS
     ./include/olp/core/porting/deprecated.h
     ./include/olp/core/porting/export.h
     ./include/olp/core/porting/make_unique.h
+    ./include/olp/core/porting/optional.hpp
     ./include/olp/core/porting/platform.h
     ./include/olp/core/porting/shared_mutex.h
     ./include/olp/core/porting/try_emplace.h

olp-cpp-sdk-core/include/olp/core/cache/CacheSettings.h

@@ -25,8 +25,7 @@
 #include <olp/core/Config.h>
 #include <olp/core/CoreApi.h>
 
-#include <olp/core/porting/deprecated.h>
-#include <boost/optional.hpp>
+#include <olp/core/porting/optional.hpp>
 
 namespace olp {
 namespace cache {
@@ -72,7 +71,7 @@ struct CORE_API CacheSettings {
    * If this parameter is not set, the downloaded data is stored
    * only in the memory cache that is limited by `#max_memory_cache_size`.
    */
-  boost::optional<std::string> disk_path_mutable = boost::none;
+  porting::optional<std::string> disk_path_mutable = porting::none;
 
   /**
    * @brief Sets the upper limit (in bytes) of the disk space that is used for
@@ -161,7 +160,7 @@ struct CORE_API CacheSettings {
    * have a stable fallback state or offline data that you can always access
    * regardless of the network state.
    */
-  boost::optional<std::string> disk_path_protected = boost::none;
+  porting::optional<std::string> disk_path_protected = porting::none;
 
   /**
    * @brief The extend permissions flag (applicable for Unix systems).

olp-cpp-sdk-core/include/olp/core/cache/KeyGenerator.h

@@ -22,9 +22,8 @@
 #include <string>
 
 #include <olp/core/CoreApi.h>
-#include <olp/core/client/HRN.h>
 #include <olp/core/geo/tiling/TileKey.h>
-#include <boost/optional.hpp>
+#include <olp/core/porting/optional.hpp>
 
 namespace olp {
 namespace cache {
@@ -77,7 +76,7 @@ class CORE_API KeyGenerator {
    */
   static std::string CreatePartitionKey(
       const std::string& hrn, const std::string& layer_id,
-      const std::string& partition_id, const boost::optional<int64_t>& version);
+      const std::string& partition_id, const porting::optional<int64_t>& version);
 
   /**
    * @brief Generates cache key for storing list of partitions.
@@ -90,7 +89,7 @@ class CORE_API KeyGenerator {
    */
   static std::string CreatePartitionsKey(
       const std::string& hrn, const std::string& layer_id,
-      const boost::optional<int64_t>& version);
+      const porting::optional<int64_t>& version);
 
   /**
    * @brief Generates cache key for storing list of available layer versions.
@@ -117,7 +116,7 @@ class CORE_API KeyGenerator {
   static std::string CreateQuadTreeKey(const std::string& hrn,
                                        const std::string& layer_id,
                                        olp::geo::TileKey root,
-                                       const boost::optional<int64_t>& version,
+                                       const porting::optional<int64_t>& version,
                                        int32_t depth);
 
   /**

olp-cpp-sdk-core/include/olp/core/client/OlpClientSettings.h

@@ -24,10 +24,9 @@
 #include <memory>
 #include <string>
 
-#include <boost/optional.hpp>
+#include <olp/core/porting/optional.hpp>
 
 #include <olp/core/client/CancellationContext.h>
-#include <olp/core/client/CancellationToken.h>
 #include <olp/core/client/DefaultLookupEndpointProvider.h>
 #include <olp/core/client/HRN.h>
 #include <olp/core/client/HttpResponse.h>
@@ -191,16 +190,16 @@ struct CORE_API OlpClientSettings {
   /**
    * @brief The network proxy settings.
    *
-   * To remove any existing proxy settings, set to `boost::none`.
+   * To remove any existing proxy settings, set to `olp::porting::none`.
    */
-  boost::optional<http::NetworkProxySettings> proxy_settings = boost::none;
+  porting::optional<http::NetworkProxySettings> proxy_settings = porting::none;
 
   /**
    * @brief The authentication settings.
    *
-   * To remove any existing authentication settings, set to `boost::none`.
+   * To remove any existing authentication settings, set to `olp::porting::none`.
    */
-  boost::optional<AuthenticationSettings> authentication_settings = boost::none;
+  porting::optional<AuthenticationSettings> authentication_settings = porting::none;
 
   /**
    * @brief The `TaskScheduler` instance.

olp-cpp-sdk-core/include/olp/core/client/OlpClientSettingsFactory.h

@@ -22,8 +22,6 @@
 #include <memory>
 #include <string>
 
-#include <boost/optional.hpp>
-
 #include "olp/core/CoreApi.h"
 #include "olp/core/http/Network.h"
 #include "olp/core/http/NetworkInitializationSettings.h"

olp-cpp-sdk-core/include/olp/core/generated/parser/ParserWrapper.h

@@ -25,7 +25,7 @@
 #include <vector>
 
 #include <rapidjson/rapidjson.h>
-#include <boost/optional.hpp>
+#include <olp/core/porting/optional.hpp>
 
 namespace olp {
 namespace parser {
@@ -57,7 +57,8 @@ inline void from_json(const rapidjson::Value& value,
 }
 
 template <typename T>
-inline void from_json(const rapidjson::Value& value, boost::optional<T>& x) {
+inline void from_json(const rapidjson::Value& value,
+                      porting::optional<T>& x) {
   T result = T();
   from_json(value, result);
   x = result;

olp-cpp-sdk-core/include/olp/core/generated/serializer/SerializerWrapper.h

@@ -25,7 +25,7 @@
 #include <vector>
 #include <utility>
 
-#include <boost/optional.hpp>
+#include <olp/core/porting/optional.hpp>
 #include <rapidjson/document.h>
 
 namespace olp {
@@ -63,10 +63,10 @@ inline void to_json(const std::shared_ptr<std::vector<unsigned char>>& x,
 }
 
 template <typename T>
-inline void to_json(const boost::optional<T>& x, rapidjson::Value& value,
+inline void to_json(const porting::optional<T>& x, rapidjson::Value& value,
                     rapidjson::Document::AllocatorType& allocator) {
   if (x) {
-    to_json(x.get(), value, allocator);
+    to_json(*x, value, allocator);
   } else {
     value.SetNull();
   }

olp-cpp-sdk-core/include/olp/core/geo/tiling/PathTiling.h

@@ -26,7 +26,7 @@
 #include <olp/core/geo/coordinates/GeoCoordinates.h>
 #include <olp/core/geo/tiling/TileKey.h>
 #include <olp/core/geo/tiling/TileKeyUtils.h>
-#include <boost/optional/optional.hpp>
+#include <olp/core/porting/optional.hpp>
 
 namespace olp {
 namespace geo {
@@ -378,7 +378,7 @@ class LineSliceIterator {
 
   LineSliceIterator& operator++() {
     if (!line_state_ || !detail::LineEvaluator::Iterate(*line_state_)) {
-      line_state_ = boost::none;
+      line_state_ = porting::none;
       ++segment_it_;
     }
     return *this;
@@ -397,7 +397,7 @@ class LineSliceIterator {
  private:
   InputIterator segment_it_;
   int32_t half_line_width_;
-  boost::optional<detail::LineEvaluator::State> line_state_;
+  porting::optional<detail::LineEvaluator::State> line_state_;
 };
 
 /**

olp-cpp-sdk-core/include/olp/core/geo/tiling/TileKey.h

@@ -23,7 +23,7 @@
 #include <cstdint>
 #include <string>
 
-#include <boost/optional.hpp>
+#include <olp/core/porting/optional.hpp>
 
 #include <olp/core/CoreApi.h>
 
@@ -504,7 +504,7 @@ using TileKeyLevels = std::bitset<TileKey::LevelCount>;
  *
  * @return The minimum level or `core::None` if the set is empty.
  */
-CORE_API boost::optional<std::uint32_t> GetMinTileKeyLevel(
+CORE_API porting::optional<std::uint32_t> GetMinTileKeyLevel(
     const TileKeyLevels& levels);
 
 /**
@@ -514,7 +514,7 @@ CORE_API boost::optional<std::uint32_t> GetMinTileKeyLevel(
  *
  * @return The maximum level or `core::None` if the set is empty.
  */
-CORE_API boost::optional<std::uint32_t> GetMaxTileKeyLevel(
+CORE_API porting::optional<std::uint32_t> GetMaxTileKeyLevel(
     const TileKeyLevels& levels);
 
 /**
@@ -526,7 +526,7 @@ CORE_API boost::optional<std::uint32_t> GetMaxTileKeyLevel(
  *
  * @return The nearest level or `core::None` if the set is empty.
  */
-CORE_API boost::optional<std::uint32_t> GetNearestAvailableTileKeyLevel(
+CORE_API porting::optional<std::uint32_t> GetNearestAvailableTileKeyLevel(
     const TileKeyLevels& levels, const std::uint32_t reference_level);
 
 /**