refactor: make use system cJSON library possible

* When USE_SYSTEM_DEPS is set, follow it.
* When USE_SYSTEM_DEPS is unset, try use system cJSON first, and 
  fallback to vendor one if not found.

Signed-off-by: Coelacanthus <[email protected]>

Author: CoelacanthusHex

CMakeLists.txt

@@ -65,7 +65,18 @@ if(CPACK_GENERATOR)
     include(CPack)
 endif()
 
-add_subdirectory(cjson)
+if (NOT DEFINED USE_SYSTEM_DEPS)
+    find_package(cJSON)
+    if (NOT CJSON_FOUND)
+        add_subdirectory(cjson)
+    endif()
+else()
+    if (USE_SYSTEM_DEPS)
+        find_package(cJSON REQUIRED)
+    else()
+        add_subdirectory(cjson)
+    endif()
+endif()
 add_subdirectory(cjson-ext)
 add_subdirectory(euicc)
 add_subdirectory(utils)

cjson-ext/CMakeLists.txt

@@ -1,4 +1,4 @@
 add_library(cjson-ext OBJECT cjson-ext/cJSON_ex.c)
 target_include_directories(cjson-ext PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
-target_link_libraries(cjson-ext PRIVATE cjson-static)
+target_link_libraries(cjson-ext PRIVATE ${CJSON_LIBRARY})
 target_compile_options(cjson-ext PRIVATE -Wall -Wextra)

driver/CMakeLists.txt

@@ -18,7 +18,7 @@ if(LPAC_DYNAMIC_DRIVERS)
 else()
     add_library(euicc-drivers STATIC ${DIR_INTERFACE_SRCS})
 endif()
-target_link_libraries(euicc-drivers euicc cjson-static lpac-utils)
+target_link_libraries(euicc-drivers euicc ${CJSON_LIBRARY} lpac-utils)
 target_include_directories(euicc-drivers PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
 
 target_sources(euicc-drivers PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/apdu/stdio.c)

euicc/CMakeLists.txt

@@ -5,7 +5,7 @@ if(LPAC_DYNAMIC_LIBEUICC)
 else()
     add_library(euicc STATIC ${LIB_EUICC_SRCS})
 endif()
-target_link_libraries(euicc cjson-static cjson-ext)
+target_link_libraries(euicc ${CJSON_LIBRARY} cjson-ext)
 target_include_directories(euicc PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/..>)
 target_compile_options(euicc PRIVATE -Wall -Wextra)
 if(LPAC_DYNAMIC_LIBEUICC)

utils/CMakeLists.txt

@@ -1,4 +1,4 @@
 add_library(lpac-utils OBJECT lpac/utils.c)
 target_include_directories(lpac-utils PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
-target_link_libraries(lpac-utils PRIVATE cjson-static euicc)
+target_link_libraries(lpac-utils PRIVATE ${CJSON_LIBRARY} euicc)
 target_compile_options(lpac-utils PRIVATE -Wall -Wextra)