Build system: add a method to get the version of an installed dependency

Author: howetuft

build-system/luxmake/utils.py

@@ -9,6 +9,9 @@
 import logging
 import shutil
 import subprocess
+import tempfile
+import pathlib
+import re
 from dataclasses import dataclass
 
 # Logger
@@ -65,7 +68,7 @@ def run_cmake(
     """Run cmake statement."""
     cmake_app = ensure_cmake_app()
     args = [cmake_app] + args
-    logger.debug(' '.join(args))
+    logger.debug(" ".join(args))
     res = subprocess.run(
         args,
         shell=False,
@@ -77,6 +80,57 @@ def run_cmake(
     return res
 
 
+_CMAKE_FIND_PACKAGE_SNIPPET = """\
+cmake_minimum_required(VERSION 4.2)
+project(find)
+find_package({0})
+message(STATUS "@@${{{0}_VERSION}}@@")
+"""
+
+_TOOLCHAIN = pathlib.Path(
+    "out", "build", "generators", "conan_toolchain.cmake"
+)
+
+
+def _run_find_package(dep):
+    """Run a find_package in cmake."""
+    with tempfile.TemporaryDirectory(delete=False) as folder:
+        folder = pathlib.Path(folder)
+        with open(folder / "CMakeLists.txt", "w") as cmakelists:
+            cmakelists.write(_CMAKE_FIND_PACKAGE_SNIPPET.format(dep))
+            cmakelists.close()
+            res = run_cmake(
+                [
+                    f"-S {folder}",
+                    f"-B {folder / 'build'}",
+                    f"-DCMAKE_TOOLCHAIN_FILE='{_TOOLCHAIN.absolute()}'",
+                    f"-DCMAKE_BUILD_TYPE='Debug'",
+                ],
+                text=True,
+                stdout=subprocess.PIPE,
+                stderr=subprocess.STDOUT,
+            )
+            res.check_returncode()
+            return res.stdout
+
+
+def get_dep_version(dep):
+    """Get the version of a given dependency, as foundable by cmake.
+
+    Important: this function assumes it is run in the root directory
+    of the projet.
+    """
+
+    # Run cmake and parse output
+    cmake_result = _run_find_package(dep)
+    versions = re.findall(r"@@([A-Za-z0-9.]+)@@", cmake_result)
+    if not versions:
+        raise ValueError(f"No dependency '{dep}' found")
+    version, *_ = versions
+
+    return version
+
+
 def unpack(path, dest):
     """Unpack a wheel."""
     args = [