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@kammce
Created November 2, 2025 20:21
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I made a script to enable module support not realizing that CMake already had the support and that I've been using Conan's CMake libraries incorrectly. I don't need this but thought I'd keep it around.
#!/usr/bin/python
#
# Copyright 2024 - 2025 Khalil Estell and the libhal contributors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from conan import ConanFile
import json
import os
from pathlib import Path
from typing import Optional
def install_cxx_modules_json(conan: ConanFile,
target_name: str,
bmi_destination: str = "bmi",
cmake_files_destination: Optional[str] = None):
"""
Reads CXXModules.json from build directory and creates a package version
with paths updated to match CMake's install destinations.
Args:
conan: The ConanFile instance
target_name: The CMake target name (e.g., "hal")
bmi_destination: Where CMake installed BMI files
(CXX_MODULES_BMI DESTINATION)
cmake_files_destination: Destination relative to the conan package
directory to place the updated
`CXXModules.json`.
Defaults to "." (conan/package_folder)
"""
# Default cmake_files_destination if not provided
if cmake_files_destination is None:
cmake_files_destination = "."
# Find the CXXModules.json file in build directory
build_modules_dir = Path(conan.build_folder) / \
"CMakeFiles" / f"{target_name}.dir"
cxx_modules_json_path = build_modules_dir / "CXXModules.json"
if not cxx_modules_json_path.exists():
conan.output.warn(
f"CXXModules.json not found at {cxx_modules_json_path}")
return
conan.output.info(
f"Processing CXXModules.json from {cxx_modules_json_path}")
# Read the original JSON
modules_data = json.loads(cxx_modules_json_path.read_text())
# Create package directory for the updated JSON
package_cmake_dir = Path(conan.package_folder) / cmake_files_destination
package_cmake_dir.mkdir(parents=True, exist_ok=True)
# Update BMI paths in modules section
if "modules" in modules_data:
for module_name, module_info in modules_data["modules"].items():
if "bmi" in module_info:
bmi_build_path = Path(module_info["bmi"])
# Update to package install location (absolute path)
bmi_filename = bmi_build_path.name
package_bmi_path = Path(
conan.package_folder) / bmi_destination / bmi_filename
module_info["bmi"] = str(package_bmi_path.absolute())
conan.output.debug(
f"Updated '{module_name}' BMI path: {bmi_filename}")
# Update references section with package-relative paths
if "references" in modules_data:
for module_name, ref_info in modules_data["references"].items():
if "path" in ref_info:
# Extract just the filename from the original path
original_path = Path(ref_info["path"])
bmi_filename = original_path.name
package_bmi_path = Path(
conan.package_folder) / bmi_destination / bmi_filename
# Update to package-relative path
ref_info["path"] = str(package_bmi_path.absolute())
conan.output.debug(
f"Updated '{module_name}' reference path: {ref_info['path']}")
# Write the updated JSON to package
package_json_path = package_cmake_dir / "CXXModules.json"
package_json_path.write_text(json.dumps(modules_data, indent=2))
conan.output.info(
f"Created package CXXModules.json at {package_json_path}")
class ConanModuleSupportConan(ConanFile):
name = "conan_module_support"
description = "Conan utilities for packaging and consuming C++20 modules with CMake"
license = "Apache-2.0"
topics = ("conan", "modules", "cmake", "cpp20")
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