Make inclusion of jsoncpp source optional (#50)

CMakeLists.txt

@@ -10,6 +10,7 @@ include(CTest)
 
 set(WERROR true CACHE BOOL "Enable warnings as errors.")
 set(WALL true CACHE BOOL "Enable all warnings.")
+set(INCLUDE_JSONCPP true CACHE BOOL "Include jsoncpp source")
 set(BUILD_SHARED_LIBS ON CACHE BOOL "Build shared libraries")
 
 if(NOT WIN32)
@@ -34,6 +35,14 @@ if(USE_CPPRESTSDK)
   set(CPPREST_LIB "cpprestsdk::cpprest")
 endif()
 
+if(NOT INCLUDE_JSONCPP)
+  find_package(jsoncpp REQUIRED)
+  # jsoncpp has different target names depending on whether it
+  # was built as a shared or static library. We make this override-able
+  # so we can be resilient to the changes between versions.
+  set(JSONCPP_LIB "jsoncpp_lib" CACHE STRING "jsoncpp target name")
+endif()
+
 include_directories (include)
 
 # TODO: We shouldn't use this, it makes the dll/lib export all symbols

README.md

@@ -21,6 +21,7 @@ Below are instructions to build on different OS's. You can also use the followin
 | -DBUILD_SAMPLES | Build the included sample project | false |
 | -DBUILD_TESTING | Builds the test project | true |
 | -DUSE_CPPRESTSDK | Includes the CppRestSDK (default http stack) | false |
+| -DINCLUDE_JSONCPP | Builds jsoncpp source code as part of the output binary | true |
 | -DWERROR | Enables warnings as errors | true |
 | -DWALL | Enables all warnings | true |
 | -DINJECT_HEADER_AFTER_STDAFX=`<header path>` | Adds the provided header to the library compilation in stdafx.cpp, intended to allow "new" and "delete" to be replaced. | `<none>` |

src/signalrclient/CMakeLists.txt

@@ -22,12 +22,11 @@ set (SOURCES
   websocket_transport.cpp
   ../../third_party_code/cpprestsdk/uri.cpp
   ../../third_party_code/cpprestsdk/uri_builder.cpp
-  ../../third_party_code/jsoncpp/jsoncpp.cpp
 )
 
 include_directories(
-    ../../third_party_code/cpprestsdk
-    ../../third_party_code/jsoncpp)
+  ../../third_party_code/cpprestsdk
+)
 
 add_library (signalrclient ${SOURCES})
 
@@ -61,6 +60,13 @@ else()
     target_compile_options(signalrclient PRIVATE -Wextra -Wpedantic -Wno-unknown-pragmas)
 endif()
 
+if(INCLUDE_JSONCPP)
+  target_sources(signalrclient PRIVATE ../../third_party_code/jsoncpp/jsoncpp.cpp)
+  target_include_directories(signalrclient PRIVATE ../../third_party_code/jsoncpp)
+else()
+  target_link_libraries(signalrclient PUBLIC ${JSONCPP_LIB})
+endif()
+
 if(NOT USE_CPPRESTSDK)
   target_link_libraries(signalrclient)
 else()