unix: move get_target_support_file() to utils

So we can use it as part of writing out Makefiles in a future commit.

Author: indygreg

cpython-unix/build.py

@@ -31,6 +31,7 @@
     download_entry,
     get_targets,
     get_target_settings,
+    get_target_support_file,
     target_needs,
     validate_python_json,
     write_package_versions,
@@ -682,7 +683,7 @@ def process_setup_line(line, variant=None):
         )
 
     with get_target_support_file(
-        "required-extensions", version, platform, target_triple
+        SUPPORT, "required-extensions", version, platform, target_triple
     ).open("r") as fh:
         required_extensions = {l.strip() for l in fh if l.strip()}
 
@@ -699,25 +700,6 @@ def process_setup_line(line, variant=None):
     return bi
 
 
-def get_target_support_file(prefix, python_version, host_platform, target_triple):
-    candidates = [
-        SUPPORT / ("%s.%s.%s" % (prefix, python_version, target_triple)),
-        SUPPORT / ("%s.%s.%s" % (prefix, python_version, host_platform)),
-    ]
-
-    for path in candidates:
-        if path.exists():
-            return path
-
-    raise Exception(
-        "Could not find support file %s for (%s, %s, %s)",
-        prefix,
-        python_version,
-        host_platform,
-        target_triple,
-    )
-
-
 def build_cpython(
     settings,
     client,
@@ -738,12 +720,12 @@ def build_cpython(
     pip_archive = download_entry("pip", DOWNLOADS_PATH)
 
     with get_target_support_file(
-        "static-modules", version, host_platform, target_triple
+        SUPPORT, "static-modules", version, host_platform, target_triple
     ).open("rb") as fh:
         static_modules_lines = [l.rstrip() for l in fh if not l.startswith(b"#")]
 
     with get_target_support_file(
-        "disabled-static-modules", version, host_platform, target_triple
+        SUPPORT, "disabled-static-modules", version, host_platform, target_triple
     ).open("rb") as fh:
         disabled_static_modules = {
             l.strip() for l in fh if l.strip() and not l.strip().startswith(b"#")

pythonbuild/utils.py

@@ -90,6 +90,27 @@ def hash_path(p: pathlib.Path):
     return h.hexdigest()
 
 
+def get_target_support_file(
+    search_dir, prefix, python_version, host_platform, target_triple
+):
+    candidates = [
+        search_dir / ("%s.%s.%s" % (prefix, python_version, target_triple)),
+        search_dir / ("%s.%s.%s" % (prefix, python_version, host_platform)),
+    ]
+
+    for path in candidates:
+        if path.exists():
+            return path
+
+    raise Exception(
+        "Could not find support file %s for (%s, %s, %s)",
+        prefix,
+        python_version,
+        host_platform,
+        target_triple,
+    )
+
+
 def write_if_different(p: pathlib.Path, data: bytes):
     """Write a file if it is missing or its content is different."""
     if p.exists():