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 commit is a third part of the task: olp-cpp-sdk-read.
Also, initial name "optional.hpp" is changed to optional.h
to avoid clang-format header sorting issue.

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

Author: asopov-here

olp-cpp-sdk-authentication/include/olp/authentication/AuthenticationClient.h

@@ -36,7 +36,7 @@
 #include <olp/authentication/Types.h>
 #include <olp/core/client/ApiResponse.h>
 #include <olp/core/client/CancellationToken.h>
-#include <olp/core/porting/optional.hpp>
+#include <olp/core/porting/optional.h>
 
 /**
  * @brief Rules all the other namespaces.

olp-cpp-sdk-authentication/include/olp/authentication/AuthenticationCredentials.h

@@ -21,7 +21,7 @@
 
 #include <string>
 
-#include <olp/core/porting/optional.hpp>
+#include <olp/core/porting/optional.h>
 #include "AuthenticationApi.h"
 
 namespace olp {

olp-cpp-sdk-authentication/include/olp/authentication/AuthenticationSettings.h

@@ -25,7 +25,7 @@
 #include <olp/authentication/AuthenticationApi.h>
 #include <olp/core/client/RetrySettings.h>
 #include <olp/core/http/NetworkProxySettings.h>
-#include <olp/core/porting/optional.hpp>
+#include <olp/core/porting/optional.h>
 
 namespace olp {
 namespace http {

olp-cpp-sdk-authentication/include/olp/authentication/AuthorizeRequest.h

@@ -23,7 +23,7 @@
 #include <vector>
 
 #include <olp/authentication/AuthenticationApi.h>
-#include <olp/core/porting/optional.hpp>
+#include <olp/core/porting/optional.h>
 
 namespace olp {
 namespace authentication {

olp-cpp-sdk-authentication/include/olp/authentication/Settings.h

@@ -24,7 +24,7 @@
 
 #include <olp/core/client/RetrySettings.h>
 #include <olp/core/http/NetworkProxySettings.h>
-#include <olp/core/porting/optional.hpp>
+#include <olp/core/porting/optional.h>
 
 #include "AuthenticationApi.h"
 #include "AuthenticationCredentials.h"

olp-cpp-sdk-authentication/include/olp/authentication/TokenResult.h

@@ -23,7 +23,7 @@
 #include <ctime>
 #include <string>
 
-#include <olp/core/porting/optional.hpp>
+#include <olp/core/porting/optional.h>
 #include "AuthenticationApi.h"
 #include "ErrorResponse.h"
 

olp-cpp-sdk-authentication/src/TokenEndpointImpl.h

@@ -29,7 +29,7 @@
 #include <olp/authentication/Types.h>
 #include <olp/core/client/CancellationContext.h>
 #include <olp/core/client/OlpClient.h>
-#include <olp/core/porting/optional.hpp>
+#include <olp/core/porting/optional.h>
 #include "TokenRequest.h"
 
 namespace olp {

olp-cpp-sdk-core/CMakeLists.txt

@@ -131,7 +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/optional.h
     ./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

@@ -24,7 +24,7 @@
 
 #include <olp/core/Config.h>
 #include <olp/core/CoreApi.h>
-#include <olp/core/porting/optional.hpp>
+#include <olp/core/porting/optional.h>
 
 namespace olp {
 namespace cache {

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

@@ -23,7 +23,7 @@
 
 #include <olp/core/CoreApi.h>
 #include <olp/core/geo/tiling/TileKey.h>
-#include <olp/core/porting/optional.hpp>
+#include <olp/core/porting/optional.h>
 
 namespace olp {
 namespace cache {