Move string_view switch to cmake

This ensures that cmake between the compiled objects and the headers
match. Previously, if they didn't match you could get linker issues.

Author: SwintonStreet

CMakeLists.txt

@@ -46,6 +46,36 @@ set(CMAKE_CXX_STANDARD 11)
 set(CMAKE_CXX_EXTENSIONS OFF)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
+set(JSONCPP_HAS_STRING_VIEW_DEFAULT OFF)
+if (${CMAKE_CXX_STANDARD} GREATER_EQUAL 17)
+    set(JSONCPP_HAS_STRING_VIEW_DEFAULT ON)
+endif()
+
+option(JSONCPP_HAS_STRING_VIEW "Enable support for string view" ${JSONCPP_HAS_STRING_VIEW_DEFAULT})
+
+configure_file(configure/configure.h.in include/json/configure.h)
+
+set(JSONCPP_INCLUDE_DIR ${CMAKE_CURRENT_BINARY_DIR}/include)
+
+file(
+    COPY include/json
+    DESTINATION ${JSONCPP_INCLUDE_DIR}
+    FILES_MATCHING
+        PATTERN "*.h"
+)
+
+set(PUBLIC_HEADERS
+    ${JSONCPP_INCLUDE_DIR}/json/config.h
+    ${JSONCPP_INCLUDE_DIR}/json/configure.h
+    ${JSONCPP_INCLUDE_DIR}/json/forwards.h
+    ${JSONCPP_INCLUDE_DIR}/json/json_features.h
+    ${JSONCPP_INCLUDE_DIR}/json/value.h
+    ${JSONCPP_INCLUDE_DIR}/json/reader.h
+    ${JSONCPP_INCLUDE_DIR}/json/version.h
+    ${JSONCPP_INCLUDE_DIR}/json/writer.h
+    ${JSONCPP_INCLUDE_DIR}/json/assertions.h
+)
+
 # Ensure that CMAKE_BUILD_TYPE has a value specified for single configuration generators.
 if(NOT DEFINED CMAKE_BUILD_TYPE AND NOT DEFINED CMAKE_CONFIGURATION_TYPES)
     set(CMAKE_BUILD_TYPE Release CACHE STRING

configure/configure.h.in

@@ -0,0 +1 @@
+#cmakedefine JSONCPP_HAS_STRING_VIEW

include/CMakeLists.txt

@@ -1,5 +1,3 @@
-file(GLOB INCLUDE_FILES "json/*.h")
 install(FILES
-    ${INCLUDE_FILES}
+    ${PUBLIC_HEADERS}
     DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/json)
-

include/json/value.h

@@ -39,17 +39,15 @@
 #endif
 #endif
 
-#if __cplusplus >= 201703L
-#define JSONCPP_HAS_STRING_VIEW 1
-#endif
-
 #include <array>
 #include <exception>
 #include <map>
 #include <memory>
 #include <string>
 #include <vector>
 
+#include "json/configure.h"
+
 #ifdef JSONCPP_HAS_STRING_VIEW
 #include <string_view>
 #endif
@@ -581,7 +579,7 @@ class JSON_API Value {
   /// Do nothing if it did not exist.
   /// \pre type() is objectValue or nullValue
   /// \post type() is unchanged
-#if JSONCPP_HAS_STRING_VIEW
+#ifdef JSONCPP_HAS_STRING_VIEW
   void removeMember(std::string_view key);
 #else
   void removeMember(const char* key);
@@ -595,7 +593,7 @@ class JSON_API Value {
    *  \param key may contain embedded nulls.
    *  \return true iff removed (no exceptions)
    */
-#if JSONCPP_HAS_STRING_VIEW
+#ifdef JSONCPP_HAS_STRING_VIEW
   bool removeMember(std::string_view key, Value* removed);
 #else
   bool removeMember(String const& key, Value* removed);

src/lib_json/CMakeLists.txt

@@ -25,19 +25,6 @@ if(NOT (HAVE_CLOCALE AND HAVE_LCONV_SIZE AND HAVE_DECIMAL_POINT AND HAVE_LOCALEC
     endif()
 endif()
 
-set(JSONCPP_INCLUDE_DIR ../../include)
-
-set(PUBLIC_HEADERS
-    ${JSONCPP_INCLUDE_DIR}/json/config.h
-    ${JSONCPP_INCLUDE_DIR}/json/forwards.h
-    ${JSONCPP_INCLUDE_DIR}/json/json_features.h
-    ${JSONCPP_INCLUDE_DIR}/json/value.h
-    ${JSONCPP_INCLUDE_DIR}/json/reader.h
-    ${JSONCPP_INCLUDE_DIR}/json/version.h
-    ${JSONCPP_INCLUDE_DIR}/json/writer.h
-    ${JSONCPP_INCLUDE_DIR}/json/assertions.h
-)
-
 source_group("Public API" FILES ${PUBLIC_HEADERS})
 
 set(JSONCPP_SOURCES
@@ -131,7 +118,7 @@ if(BUILD_SHARED_LIBS)
 
     target_include_directories(${SHARED_LIB} PUBLIC
         $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
-        $<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/${JSONCPP_INCLUDE_DIR}>
+        $<BUILD_INTERFACE:${JSONCPP_INCLUDE_DIR}>
     )
 
     list(APPEND CMAKE_TARGETS ${SHARED_LIB})
@@ -164,7 +151,7 @@ if(BUILD_STATIC_LIBS)
 
     target_include_directories(${STATIC_LIB} PUBLIC
         $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
-        $<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/${JSONCPP_INCLUDE_DIR}>
+        $<BUILD_INTERFACE:${JSONCPP_INCLUDE_DIR}>
     )
 
     list(APPEND CMAKE_TARGETS ${STATIC_LIB})
@@ -190,7 +177,7 @@ if(BUILD_OBJECT_LIBS)
 
     target_include_directories(${OBJECT_LIB} PUBLIC
         $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
-        $<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/${JSONCPP_INCLUDE_DIR}>
+        $<BUILD_INTERFACE:${JSONCPP_INCLUDE_DIR}>
     )
 
     list(APPEND CMAKE_TARGETS ${OBJECT_LIB})
@@ -202,4 +189,3 @@ install(TARGETS ${CMAKE_TARGETS} ${INSTALL_EXPORT}
     ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
     OBJECTS DESTINATION ${CMAKE_INSTALL_LIBDIR}
 )
-

src/lib_json/json_value.cpp

@@ -5,6 +5,7 @@
 
 #if !defined(JSON_IS_AMALGAMATION)
 #include <json/assertions.h>
+#include <json/configure.h>
 #include <json/value.h>
 #include <json/writer.h>
 #endif // if !defined(JSON_IS_AMALGAMATION)