Extract GenerateWinMD.cmake to avoid recursive CMake invocation

CMakeLists.txt

@@ -20,7 +20,7 @@ message(STATUS "Building Generator subproject...")
 execute_process(
     COMMAND ${CMAKE_COMMAND} --build "${CMAKE_CURRENT_BINARY_DIR}/Generator"
     COMMAND_ERROR_IS_FATAL ANY)
-set(SWIFT_WINRT_EXE "${CMAKE_CURRENT_BINARY_DIR}/Generator/Sources/SwiftWinRT/SwiftWinRT.exe")
+set(SWIFTWINRT_EXE "${CMAKE_CURRENT_BINARY_DIR}/Generator/Sources/SwiftWinRT/SwiftWinRT.exe")
 
-# Now build InteropTests, which depends on SWIFT_WINRT_EXE
+# Now build InteropTests, which depends on SWIFTWINRT_EXE
 add_subdirectory(InteropTests)

InteropTests/CMakeLists.txt

@@ -4,44 +4,43 @@ if(NOT DEFINED CMAKE_PROJECT_NAME)
     project(InteropTests LANGUAGES C Swift)
 endif()
 
-if (NOT DEFINED SWIFT_WINRT_EXE)
-    message(FATAL_ERROR "SWIFT_WINRT_EXE must be defined")
+if (NOT DEFINED SWIFTWINRT_EXE)
+    message(FATAL_ERROR "SWIFTWINRT_EXE must be defined")
 endif()
-cmake_path(ABSOLUTE_PATH SWIFT_WINRT_EXE NORMALIZE OUTPUT_VARIABLE SWIFT_WINRT_EXE)
+cmake_path(ABSOLUTE_PATH SWIFTWINRT_EXE NORMALIZE OUTPUT_VARIABLE SWIFTWINRT_EXE)
 
 # Generating projection sources will depend on WinRTComponent.winmd, so build it now
-message(STATUS "Configuring WinRTComponent subproject...")
-execute_process(
-    COMMAND ${CMAKE_COMMAND}
-        -S "${CMAKE_CURRENT_SOURCE_DIR}/WinRTComponent"
-        -B "${CMAKE_CURRENT_BINARY_DIR}/WinRTComponent"
-        -G "${CMAKE_GENERATOR}"
-        -D "CMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}"
-        -D CMAKE_CXX_COMPILER=cl.exe
-        -D "CMAKE_CXX_FLAGS=/std:c++latest /W4 /EHsc"
-    COMMAND_ERROR_IS_FATAL ANY)
-
-message(STATUS "Building WinRTComponent subproject...")
-execute_process(
-    COMMAND ${CMAKE_COMMAND}
-        --build "${CMAKE_CURRENT_BINARY_DIR}/WinRTComponent"
-    COMMAND_ERROR_IS_FATAL ANY)
-set(WINRTCOMPONENT_BINARY_DIR "${CMAKE_CURRENT_BINARY_DIR}/WinRTComponent")
+set(WINRTCOMPONENT_IDL "${CMAKE_CURRENT_SOURCE_DIR}/WinRTComponent/WinRTComponent.idl")
+set(WINRTCOMPONENT_WINMD "${CMAKE_CURRENT_BINARY_DIR}/WinRTComponent.winmd")
+include(WinRTComponent/GenerateWinMD.cmake)
 
 # Generate Swift projection
 message(STATUS "Generating Swift projection for WinRTComponent...")
 cmake_path(CONVERT "${CMAKE_CURRENT_SOURCE_DIR}/GenerateProjection.ps1" TO_NATIVE_PATH_LIST SCRIPT_PATH_NATIVE)
-cmake_path(CONVERT "${SWIFT_WINRT_EXE}" TO_NATIVE_PATH_LIST SWIFT_WINRT_EXE_NATIVE)
-cmake_path(CONVERT "${WINRTCOMPONENT_BINARY_DIR}/WinRTComponent.winmd" TO_NATIVE_PATH_LIST WINMD_NATIVE)
+cmake_path(CONVERT "${SWIFTWINRT_EXE}" TO_NATIVE_PATH_LIST SWIFTWINRT_EXE_NATIVE)
+cmake_path(CONVERT "${WINRTCOMPONENT_WINMD}" TO_NATIVE_PATH_LIST WINRTCOMPONENT_WINMD_NATIVE)
 cmake_path(CONVERT "${CMAKE_CURRENT_BINARY_DIR}/Generated/Sources" TO_NATIVE_PATH_LIST OUTPUT_DIR_NATIVE)
 set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS "${SCRIPT_PATH_ARG}")
 execute_process(
     COMMAND powershell.exe -File "${SCRIPT_PATH_NATIVE}"
-        -SwiftWinRT "${SWIFT_WINRT_EXE_NATIVE}"
-        -WinMD "${WINMD_NATIVE}"
+        -SwiftWinRT "${SWIFTWINRT_EXE_NATIVE}"
+        -WinMD "${WINRTCOMPONENT_WINMD_NATIVE}"
         -OutputDir "${OUTPUT_DIR_NATIVE}"
     COMMAND_ERROR_IS_FATAL ANY)
 
+# Define WinRTComponent build (requires the cl.exe compiler)
+include(ExternalProject)
+message(STATUS "Building WinRTComponent...")
+ExternalProject_Add(WinRTComponent
+    SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/WinRTComponent"
+    BINARY_DIR "${CMAKE_CURRENT_BINARY_DIR}/WinRTComponent"
+    CMAKE_ARGS
+        -D "WINRTCOMPONENT_WINMD=${WINRTCOMPONENT_WINMD}"
+        -D "CMAKE_CXX_COMPILER=cl.exe"
+        -D "CMAKE_CXX_FLAGS=/std:c++latest /W4 /EHsc"
+    INSTALL_COMMAND ""
+    TEST_COMMAND "")
+
 # Build the support module if not already the case (by root CMakeLists.txt)
 if(NOT TARGET WindowsRuntime)
     add_subdirectory(../Support "${CMAKE_CURRENT_BINARY_DIR}/Support")

InteropTests/WinRTComponent/CMakeLists.txt

@@ -2,37 +2,23 @@ cmake_minimum_required(VERSION 3.21.0)
 
 project(WinRTComponent LANGUAGES CXX)
 
-# Generate the WinMDs from the idl files
-message(STATUS "Generating WinRTComponent.winmd...")
-set(MIDLRT.EXE_PATH_NATIVE "$ENV{WindowsSdkVerBinPath}$ENV{VSCMD_ARG_HOST_ARCH}\\midlrt.exe")
-cmake_path(CONVERT "$ENV{WindowsSdkDir}References\\$ENV{WindowsSDKVersion}" TO_CMAKE_PATH_LIST WINSDK_REFERENCES_DIR NORMALIZE)
-set(FOUNDATIONCONTRACT_DIR "${WINSDK_REFERENCES_DIR}/Windows.Foundation.FoundationContract/4.0.0.0")
-cmake_path(CONVERT "${FOUNDATIONCONTRACT_DIR}" TO_NATIVE_PATH_LIST METADATA_DIR_NATIVE)
-cmake_path(CONVERT "${FOUNDATIONCONTRACT_DIR}/Windows.Foundation.FoundationContract.winmd" TO_NATIVE_PATH_LIST FOUNDATIONCONTRACT_WINMD_NATIVE)
-cmake_path(CONVERT "${WINSDK_REFERENCES_DIR}/Windows.Foundation.UniversalApiContract/15.0.0.0/Windows.Foundation.UniversalApiContract.winmd" TO_NATIVE_PATH_LIST UNIVERSALAPICONTRACT_WINMD_NATIVE)
-cmake_path(CONVERT "${CMAKE_CURRENT_BINARY_DIR}/WinRTComponent.winmd" TO_NATIVE_PATH_LIST WINRTCOMPONENT_WINMD_PATH_NATIVE)
-cmake_path(CONVERT "${CMAKE_CURRENT_BINARY_DIR}/WinRTComponent.h" TO_NATIVE_PATH_LIST WINRTCOMPONENT_H_PATH_NATIVE)
-cmake_path(CONVERT "${CMAKE_CURRENT_SOURCE_DIR}/WinRTComponent.idl" TO_NATIVE_PATH_LIST IDL_PATH_NATIVE)
-execute_process(
-    COMMAND "${MIDLRT.EXE_PATH_NATIVE}"
-        /W1 /nologo /nomidl
-        /metadata_dir "${METADATA_DIR_NATIVE}"
-        /reference "${FOUNDATIONCONTRACT_WINMD_NATIVE}"
-        /reference "${UNIVERSALAPICONTRACT_WINMD_NATIVE}"
-        /winmd "${WINRTCOMPONENT_WINMD_PATH_NATIVE}"
-        /header "${WINRTCOMPONENT_H_PATH_NATIVE}"
-        "${IDL_PATH_NATIVE}"
-    COMMAND_ERROR_IS_FATAL ANY)
+# Generate the WinRTComponent.winmd file if not previously done
+if(NOT DEFINED WINRTCOMPONENT_WINMD)
+    set(WINRTCOMPONENT_IDL "${CMAKE_CURRENT_SOURCE_DIR}/WinRTComponent.idl")
+    set(WINRTCOMPONENT_WINMD "${CMAKE_CURRENT_BINARY_DIR}/WinRTComponent.winmd")
+    include(GenerateWinMD.cmake)
+endif()
 
 # Generate the C++/WinRT boilerplate
 message(STATUS "Generating C++/WinRT boilerplate for WinRTComponent...")
-set(CPPWINRT.EXE_PATH_NATIVE "$ENV{WindowsSdkVerBinPath}$ENV{VSCMD_ARG_HOST_ARCH}\\cppwinrt.exe")
+set(CPPWINRT_EXE_NATIVE "$ENV{WindowsSdkVerBinPath}$ENV{VSCMD_ARG_HOST_ARCH}\\cppwinrt.exe")
+cmake_path(CONVERT "${WINRTCOMPONENT_WINMD}" TO_NATIVE_PATH_LIST WINRTCOMPONENT_WINMD_NATIVE)
 string(REPLACE "\\" "" WINSDK_VERSION "$ENV{WindowsSDKVersion}")
 set(CPPWINRT_GENERATED_DIR "${CMAKE_CURRENT_BINARY_DIR}/CppWinRT")
 cmake_path(CONVERT "${CPPWINRT_GENERATED_DIR}" TO_NATIVE_PATH_LIST CPPWINRT_GENERATED_DIR_NATIVE)
 execute_process(
-    COMMAND "${CPPWINRT.EXE_PATH_NATIVE}"
-        -input "${WINRTCOMPONENT_WINMD_PATH_NATIVE}"
+    COMMAND "${CPPWINRT_EXE_NATIVE}"
+        -input "${WINRTCOMPONENT_WINMD_NATIVE}"
         -reference "${WINSDK_VERSION}"
         -component "${CPPWINRT_GENERATED_DIR_NATIVE}" -overwrite -optimize
         -output "${CPPWINRT_GENERATED_DIR_NATIVE}"
@@ -47,4 +33,6 @@ add_library(WinRTComponent SHARED
 target_include_directories(WinRTComponent PRIVATE
     "${CMAKE_CURRENT_SOURCES_DIR}"
     "${CPPWINRT_GENERATED_DIR}")
-target_precompile_headers(WinRTComponent PRIVATE pch.h)
+target_precompile_headers(WinRTComponent PRIVATE pch.h)
+
+set(WINRTCOMPONENT_WINMD "${CMAKE_CURRENT_BINARY_DIR}/WinRTComponent.winmd" PARENT_SCOPE)

InteropTests/WinRTComponent/GenerateWinMD.cmake

@@ -0,0 +1,29 @@
+# Generates the WinRTComponent.winmd file from the WinRTComponent.idl file.
+if(NOT DEFINED WINRTCOMPONENT_IDL)
+    message(FATAL_ERROR "WINRTCOMPONENT_IDL is not defined")
+endif()
+
+if(NOT DEFINED WINRTCOMPONENT_WINMD)
+    message(FATAL_ERROR "WINRTCOMPONENT_WINMD_PATH is not defined")
+endif()
+
+message(STATUS "Generating WinRTComponent.winmd...")
+set(MIDLRT_EXE_NATIVE "$ENV{WindowsSdkVerBinPath}$ENV{VSCMD_ARG_HOST_ARCH}\\midlrt.exe")
+cmake_path(CONVERT "$ENV{WindowsSdkDir}References\\$ENV{WindowsSDKVersion}" TO_CMAKE_PATH_LIST WINSDK_REFERENCES_DIR NORMALIZE)
+set(FOUNDATIONCONTRACT_DIR "${WINSDK_REFERENCES_DIR}/Windows.Foundation.FoundationContract/4.0.0.0")
+cmake_path(CONVERT "${FOUNDATIONCONTRACT_DIR}" TO_NATIVE_PATH_LIST METADATA_DIR_NATIVE)
+cmake_path(CONVERT "${FOUNDATIONCONTRACT_DIR}/Windows.Foundation.FoundationContract.winmd" TO_NATIVE_PATH_LIST FOUNDATIONCONTRACT_WINMD_NATIVE)
+cmake_path(CONVERT "${WINSDK_REFERENCES_DIR}/Windows.Foundation.UniversalApiContract/15.0.0.0/Windows.Foundation.UniversalApiContract.winmd" TO_NATIVE_PATH_LIST UNIVERSALAPICONTRACT_WINMD_NATIVE)
+cmake_path(CONVERT "${WINRTCOMPONENT_WINMD}" TO_NATIVE_PATH_LIST WINRTCOMPONENT_WINMD_NATIVE)
+string(REPLACE ".winmd" ".h" WINRTCOMPONENT_H_NATIVE "${WINRTCOMPONENT_WINMD_NATIVE}")
+cmake_path(CONVERT "${WINRTCOMPONENT_IDL}" TO_NATIVE_PATH_LIST WINRTCOMPONENT_IDL_NATIVE)
+execute_process(
+    COMMAND "${MIDLRT_EXE_NATIVE}"
+        /W1 /nologo /nomidl
+        /metadata_dir "${METADATA_DIR_NATIVE}"
+        /reference "${FOUNDATIONCONTRACT_WINMD_NATIVE}"
+        /reference "${UNIVERSALAPICONTRACT_WINMD_NATIVE}"
+        /winmd "${WINRTCOMPONENT_WINMD_NATIVE}"
+        /header "${WINRTCOMPONENT_H_NATIVE}"
+        "${WINRTCOMPONENT_IDL_NATIVE}"
+    COMMAND_ERROR_IS_FATAL ANY)