Feature/better find package

CMakeLists.txt

@@ -8,22 +8,6 @@ if(NOT CMAKE_BUILD_TYPE)
     FORCE)
 endif(NOT CMAKE_BUILD_TYPE)
 
-# Use find_package everywhere, no-op if it's a subproject
-macro(find_package)
-  if(NOT TARGET ${ARGV0} AND NOT TARGET ${ARGV0}::${ARGV0})
-    _find_package(${ARGV})
-  else()
-    if(TARGET ${ARGV0})
-      get_target_property(TGT_VER ${ARGV0} VERSION)
-      set(TGT ${ARGV0})
-    else()
-      get_target_property(TGT_VER ${ARGV0}::${ARGV0} VERSION)
-      set(TGT ${ARGV0}::${ARGV0})
-    endif()
-    message(STATUS "Found ${ARGV0}: CMake Target ${TGT} (found version \"${TGT_VER}\")")
-    set(${ARGV0}_FOUND TRUE)
-  endif()
-endmacro()
 # Apple: Don't modify install_name when touching RPATH.
 if(POLICY CMP0068)
   cmake_policy(SET CMP0068 NEW)
@@ -51,6 +35,19 @@ endif()
 
 include(CMakeDependentOption)
 option(BUILD_DEPS "Force re-build of all dependencies" ON)
+CMAKE_DEPENDENT_OPTION(BUILD_gflags "Install the gflags dependency Library" ON
+  "BUILD_DEPS;" OFF)
+CMAKE_DEPENDENT_OPTION(BUILD_glog "Install the glog dependency Library" ON
+  "BUILD_DEPS;" OFF)
+CMAKE_DEPENDENT_OPTION(BUILD_ZLIB "Install the ZLIB dependency Library" ON
+  "BUILD_DEPS;" OFF)
+CMAKE_DEPENDENT_OPTION(BUILD_Protobuf "Install the Protobuf dependency Library" ON
+  "BUILD_DEPS;" OFF)
+CMAKE_DEPENDENT_OPTION(BUILD_abseil-cpp "Install the abseil-cpp dependency Library" ON
+  "BUILD_DEPS;" OFF)
+CMAKE_DEPENDENT_OPTION(BUILD_Cbc "Install the Cbc dependency Library" ON
+  "BUILD_DEPS;" OFF)
+
 option(BUILD_CXX "Build C++ library" ON)
 CMAKE_DEPENDENT_OPTION(BUILD_PYTHON "Build Python Library" OFF
   "BUILD_CXX; NOT ORTOOLS_IS_SUBPROJECT" OFF)
@@ -66,8 +63,26 @@ message(STATUS "Build Java Binding: ${BUILD_JAVA}")
 message(STATUS "Build .Net Binding: ${BUILD_DOTNET}")
 
 # Add OR Tools Dependencies as CMake subproject if missing
-if(BUILD_DEPS)
-  add_subdirectory(cmake/external external)
+if(NOT DEFINED Swig_MODULE_PATH AND BUILD_DEPS)
+  set(Swig_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake/external/Swig)
+endif()
+if(BUILD_gflags)
+  include(${CMAKE_CURRENT_SOURCE_DIR}/cmake/external/gflags/ExternalProject_gflags.cmake)
+endif()
+if(BUILD_glog)
+  include(${CMAKE_CURRENT_SOURCE_DIR}/cmake/external/glog/ExternalProject_glog.cmake)
+endif()
+if(BUILD_ZLIB)
+  include(${CMAKE_CURRENT_SOURCE_DIR}/cmake/external/ZLIB/ExternalProject_ZLIB.cmake)
+endif()
+if(BUILD_Protobuf)
+  include(${CMAKE_CURRENT_SOURCE_DIR}/cmake/external/Protobuf/ExternalProject_Protobuf.cmake)
+endif()
+if(BUILD_abseil-cpp)
+  include(${CMAKE_CURRENT_SOURCE_DIR}/cmake/external/abseil-cpp/ExternalProject_abseil-cpp.cmake)
+endif()
+if(BUILD_Cbc)
+  include(${CMAKE_CURRENT_SOURCE_DIR}/cmake/external/Cbc/ExternalProject_Cbc.cmake)
 endif()
 
 if(BUILD_CXX)

cmake/cpp.cmake

@@ -42,12 +42,130 @@ if(MSVC)
 else()
   add_definitions(-fwrapv)
 endif()
-add_definitions(-DUSE_GLOP -DUSE_BOP -DUSE_CBC -DUSE_CLP)
+
+set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+
+# Force dependencies to be built as static
+set(BUILD_SHARED_BCKP ${BUILD_SHARED_LIBS})
+set(BUILD_SHARED_LIBS OFF)
+
+# Disable test rules for dependencies
+set(BUILD_TESTING OFF)
+
+# Since it is not possible to ALIAS an already aliased target, this macro get
+# the real target name of an aliased target and create a new alias
+macro(alias_target target_to_aliased alias_name)
+	get_target_property(alias_TARGET ${target_to_aliased} ALIASED_TARGET)
+	if (NOT ${alias_TARGET})
+    # The target was not an alias so we can use it !
+		set(alias_TARGET ${target_to_aliased})
+	endif()
+	add_library(${alias_name} ALIAS ${alias_TARGET})
+endmacro()
+
+########
+# Swig #
+########
+
+if(WIN32 AND (BUILD_PYTHON OR BUILD_JAVA OR BUILD_CSHARP))
+    find_package(Swig REQUIRED)
+endif()
+
+##########
+# gflags #
+##########
+
+find_package(gflags REQUIRED)
+
+if(NOT TARGET gflags::gflags)
+  if(TARGET gflags)
+    set_target_properties(gflags PROPERTIES IMPORTED_GLOBAL TRUE)
+    alias_target(gflags gflags::gflags)
+  else()
+    message(FATAL_ERROR "Cannot find target gflags::gflags")
+  endif()
+endif()
+
+########
+# glog #
+########
+
+find_package(glog REQUIRED)
+
+if(NOT TARGET glog::glog)
+  if(TARGET glog)
+    set_target_properties(glog PROPERTIES IMPORTED_GLOBAL TRUE)
+    alias_target(glog glog::glog)
+  else()
+    message(FATAL_ERROR "Cannot find target glog::glog")
+  endif()
+endif()
+
+########
+# ZLIB #
+########
+
+find_package(ZLIB REQUIRED)
+
+if(NOT TARGET ZLIB::ZLIB)
+  if(BUILD_SHARED_LIBS AND TARGET ZLIB::zlib)
+    set_target_properties(ZLIB::zlib PROPERTIES IMPORTED_GLOBAL TRUE)
+    alias_target(ZLIB::zlib ZLIB::ZLIB)
+  elseif(NOT BUILD_SHARED_LIBS AND TARGET ZLIB::zlibstatic)
+    set_target_properties(ZLIB::zlibstatic PROPERTIES IMPORTED_GLOBAL TRUE)
+    alias_target(ZLIB::zlibstatic ZLIB::ZLIB)
+  else()
+    message(FATAL_ERROR "Cannot find target ZLIB::ZLIB")
+  endif()
+endif()
+
+############
+# Protobuf #
+############
+
+find_package(Protobuf REQUIRED)
+
+# By default, not present until CMake v3.9
+if(NOT TARGET protobuf::libprotobuf)
+  if(TARGET libprotobuf)
+    set_target_properties(libprotobuf PROPERTIES IMPORTED_GLOBAL TRUE)
+    add_library(protobuf::libprotobuf ALIAS libprotobuf)
+  else()
+    message(FATAL_ERROR "Cannot find target protobuf::libprotobuf")
+  endif()
+endif()
+
+# By default, not present until CMake v3.10
+if(NOT TARGET protobuf::protoc)
+  if(TARGET protoc)
+    set_target_properties(libprotoc PROPERTIES IMPORTED_GLOBAL TRUE)
+    add_library(protobuf::protoc ALIAS protoc)
+  else()
+    message(FATAL_ERROR "Cannot find target protobuf::protoc")
+  endif()
+endif()
+
+##########
+# abseil #
+##########
+
+find_package(abseil-cpp REQUIRED)
+
+#######
+# Cbc #
+#######
+
+find_package(Cbc REQUIRED)
+
+# Reapply previous state
+set(BUILD_SHARED_LIBS ${BUILD_SHARED_BCKP})
 
 # Verify Dependencies
 set(CMAKE_THREAD_PREFER_PTHREAD TRUE)
 find_package(Threads REQUIRED)
 
+add_definitions(-DUSE_GLOP -DUSE_BOP -DUSE_CBC -DUSE_CLP)
+
 # Main Target
 add_library(${PROJECT_NAME} "")
 target_compile_features(${PROJECT_NAME} PRIVATE cxx_std_11)
@@ -77,15 +195,15 @@ target_include_directories(${PROJECT_NAME} INTERFACE
   )
 target_link_libraries(${PROJECT_NAME} PUBLIC
   ZLIB::ZLIB
-  absl::base
-  absl::container
-  absl::hash
-  absl::memory
-  absl::meta
-  absl::str_format
-  absl::strings
-  absl::synchronization
-  absl::types
+  absl::absl_base
+  absl::absl_container
+  absl::absl_hash
+  absl::absl_memory
+  absl::absl_meta
+  absl::absl_str_format
+  absl::absl_strings
+  absl::absl_synchronization
+  absl::absl_types
   gflags::gflags glog::glog
   protobuf::libprotobuf
   Cbc::CbcSolver Cbc::OsiCbc Cbc::ClpSolver Cbc::OsiClp
@@ -124,7 +242,7 @@ foreach (PROTO_FILE ${proto_files})
     OUTPUT ${PROTO_SRC} ${PROTO_HDR}
     COMMAND protobuf::protoc
     "--proto_path=${PROJECT_SOURCE_DIR}"
-    "${PROTO_DIRS}"
+    ${PROTO_DIRS}
     "--cpp_out=${PROJECT_BINARY_DIR}"
     ${PROTO_FILE}
     DEPENDS ${PROTO_FILE} protobuf::protoc