1 files changed, 83 insertions, 0 deletions
diff --git a/lib/python/qmk/makefile.py b/lib/python/qmk/makefile.py
new file mode 100644
index 0000000000..8645056d2d
--- /dev/null
+++ b/lib/python/qmk/makefile.py
@@ -0,0 +1,83 @@
+""" Functions for working with Makefiles
+"""
+from pathlib import Path
+
+from qmk.errors import NoSuchKeyboardError
+
+
+def parse_rules_mk_file(file, rules_mk=None):
+    """Turn a rules.mk file into a dictionary.
+
+    Args:
+        file: path to the rules.mk file
+        rules_mk: already parsed rules.mk the new file should be merged with
+
+    Returns:
+        a dictionary with the file's content
+    """
+    if not rules_mk:
+        rules_mk = {}
+
+    file = Path(file)
+    if file.exists():
+        rules_mk_lines = file.read_text().split("\n")
+
+        for line in rules_mk_lines:
+            # Filter out comments
+            if line.strip().startswith("#"):
+                continue
+
+            # Strip in-line comments
+            if '#' in line:
+                line = line[:line.index('#')].strip()
+
+            if '=' in line:
+                # Append
+                if '+=' in line:
+                    key, value = line.split('+=', 1)
+                    if key.strip() not in rules_mk:
+                        rules_mk[key.strip()] = value.strip()
+                    else:
+                        rules_mk[key.strip()] += ' ' + value.strip()
+                # Set if absent
+                elif "?=" in line:
+                    key, value = line.split('?=', 1)
+                    if key.strip() not in rules_mk:
+                        rules_mk[key.strip()] = value.strip()
+                else:
+                    if ":=" in line:
+                        line.replace(":", "")
+                    key, value = line.split('=', 1)
+                    rules_mk[key.strip()] = value.strip()
+
+    return rules_mk
+
+
+def get_rules_mk(keyboard):
+    """ Get a rules.mk for a keyboard
+
+    Args:
+        keyboard: name of the keyboard
+
+    Raises:
+        NoSuchKeyboardError: when the keyboard does not exists
+
+    Returns:
+        a dictionary with the content of the rules.mk file
+    """
+    # Start with qmk_firmware/keyboards
+    kb_path = Path.cwd() / "keyboards"
+    # walk down the directory tree
+    # and collect all rules.mk files
+    kb_dir = kb_path / keyboard
+    if kb_dir.exists():
+        rules_mk = dict()
+        for directory in Path(keyboard).parts:
+            kb_path = kb_path / directory
+            rules_mk_path = kb_path / "rules.mk"
+            if rules_mk_path.exists():
+                rules_mk = parse_rules_mk_file(rules_mk_path, rules_mk)
+    else:
+        raise NoSuchKeyboardError("The requested keyboard and/or revision does not exist.")
+
+    return rules_mk