Added flags to force rebuild of all dependencies, created hierarchy b/w python and C++ projects when the C++ project is being built

CMakeLists.txt

@@ -28,6 +28,7 @@ ENDIF()
 
 SET(BUILD_CXX OFF CACHE BOOL "Build C++ library")
 SET(BUILD_PY OFF CACHE BOOL "Build Python library")
+SET(BUILD_DEPS OFF CACHE BOOL "Force re-build of all dependencies")
 
 SET(DOWNLOAD_LOCATION "${CMAKE_CURRENT_BINARY_DIR}/downloads" CACHE PATH "Location where external projects will be downloaded.")
 MARK_AS_ADVANCED(DOWNLOAD_LOCATION)
@@ -52,9 +53,14 @@ ENDIF()
 FIND_PACKAGE(Threads REQUIRED)
 
 FIND_PACKAGE(Protobuf ${Protobuf_VERSION})
+IF(BUILD_DEPS)
+    SET(Protobuf_FOUND False)
+ENDIF()
 IF(NOT Protobuf_FOUND)
-    MESSAGE(STATUS "Did not find system protobuf. Building as an external project")
+    MESSAGE(STATUS "Did not find system protobuf or forced build. Building as an external project")
     INCLUDE(cmake/external/protobuf.cmake)
+ELSE()
+    MESSAGE("Protobuf_FOUND: ${Protobuf_FOUND}")
 ENDIF()
 INCLUDE_DIRECTORIES(${Protobuf_INCLUDE_DIRS})
 SET(PROTOBUF_IMPORT_DIRS ${PROJECT_SOURCE_DIR})

cmake/cpp.cmake

@@ -1,12 +1,18 @@
 INCLUDE_DIRECTORIES(${PROJECT_SOURCE_DIR})
 FIND_PACKAGE(gflags ${gflags_VERSION})
+IF(BUILD_DEPS)
+    SET(gflags_FOUND False)
+ENDIF()
 IF(NOT gflags_FOUND)
-    MESSAGE(STATUS "Did not find system gflags. Building as an external project")
-    INCLUDE(external/gflags.cmake)
+    MESSAGE(STATUS "Did not find system gflags or forced build. Building as an external project")
+    INCLUDE(cmake/external/gflags.cmake)
 ENDIF()
 INCLUDE_DIRECTORIES(${gflags_INCLUDE_DIRS})
 
 FIND_PACKAGE(glog ${glog_VERSION})
+IF(BUILD_DEPS)
+    SET(glog_FOUND False)
+ENDIF()
 IF(NOT glog_FOUND)
     MESSAGE(STATUS "Did not find system glog. Building as an external project.")
     INCLUDE(cmake/external/glog.cmake)
@@ -14,6 +20,9 @@ ENDIF()
 INCLUDE_DIRECTORIES(${glog_INCLUDE_DIRS})
 
 FIND_PACKAGE(Cbc ${Cbc_VERSION})
+IF(BUILD_DEPS)
+    SET(Cbc_FOUND False)
+ENDIF()
 IF(NOT Cbc_FOUND)
     IF(NOT MSVC)
         MESSAGE(STATUS "Did not find system coin-cbc. Building as an external project.")
@@ -33,7 +42,6 @@ ENDIF()
 FILE(GLOB_RECURSE proto_files RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} "ortools/*.proto")
 PROTOBUF_GENERATE_CPP(PROTO_SRCS PROTO_HDRS ${proto_files})
 ADD_CUSTOM_TARGET(${PROJECT_NAME}ProtoSources ALL DEPENDS ${PROTO_SRCS})
-
 ADD_LIBRARY(${PROJECT_NAME}Proto OBJECT ${PROTO_SRCS} ${PROTO_HDRS})
 
 IF(NOT Cbc_FOUND)

cmake/python.cmake

@@ -5,6 +5,10 @@ LIST(REMOVE_ITEM py_proto_files "ortools/constraint_solver/demon_profiler.proto"
 PROTOBUF_GENERATE_PYTHON(PROTO_PY_SRCS ${py_proto_files})
 ADD_CUSTOM_TARGET(Py${PROJECT_NAME}proto ALL DEPENDS ${PROTO_PY_SRCS})
 
+IF(BUILD_CXX)
+    ADD_DEPENDENCIES(Py${PROJECT_NAME}proto ${PROJECT_NAME})
+ENDIF()
+
 IF(${PYTHON_VERSION_STRING} VERSION_GREATER 3)
     SET(CMAKE_SWIG_FLAGS "-py3;-DPY3")
 ENDIF()
@@ -66,4 +70,8 @@ ADD_CUSTOM_COMMAND(
     COMMAND ${CMAKE_COMMAND} -E touch ${PY_OUTPUT}
     DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/ortools/__init__.py)
 ADD_CUSTOM_TARGET(py${PROJECT_NAME} ALL DEPENDS ${PY_OUTPUT})
+
+IF(BUILD_CXX)
+    ADD_DEPENDENCIES(py${PROJECT_NAME} ${PROJECT_NAME})
+ENDIF()
 INSTALL(CODE "execute_process(COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_BINARY_DIR}/setup.py install)")