parse_version.py

#!/usr/bin/env python3
"""Generate a version header for the Bazel build.

To reduce duplication in version number strings, this script parses
pico_sdk_version.cmake to produce a version header containing the SDK version
information.
"""

import argparse
import re
import sys


def _parse_args():
    parser = argparse.ArgumentParser(
        description=__doc__,
    )
    parser.add_argument(
        "pico_sdk_version_file",
        type=argparse.FileType("r"),
        help="Path to pico_sdk_version.cmake",
    )
    parser.add_argument(
        "--template",
        type=argparse.FileType("r"),
        required=True,
        help="Path to version.h.in",
    )
    parser.add_argument(
        "-o",
        "--output",
        type=argparse.FileType("w"),
        default=sys.stdout.buffer,
        help="Output file path. Defaults to stdout.",
    )
    return parser.parse_args()


_EXPANSION_REGEX = re.compile("(?:\$\{)([a-zA-Z]\w*)(?:\})")
_SET_REGEX = re.compile("(?:set\()([a-zA-Z]\w*)[ ](.*)(?:\))")
_COND_REGEX = re.compile("(?:if\s+\()([a-zA-Z]\w*)(?:\))")
_END_COND_REGEX = re.compile("(?:endif\(\))")


class RudimentaryCmakeParser:
    def __init__(self, in_file):
        self._condition_stack = []
        self._known_vars = {}

        for line in in_file.readlines():
            line = line.split("#")[0]
            self._check_for_condition(line)
            self._check_for_condition_end(line)
            self._check_for_define(line)

    def _expand_str(self, contents):
        return _EXPANSION_REGEX.sub(
            lambda val: str(self._known_vars.get(val.group(1))), contents
        )

    def _eval_value(self, value):
        value = self._expand_str(value.strip('"'))
        typed_value = value
        try:
            typed_value = float(value)
        except ValueError:
            pass
        try:
            typed_value = int(value)
        except ValueError:
            pass

        return typed_value

    def _check_for_condition(self, line):
        maybe_cond = _COND_REGEX.search(line)
        if maybe_cond:
            self._condition_stack.append(
                bool(self._known_vars.get(maybe_cond.group(1)))
            )

    def _check_for_condition_end(self, line):
        maybe_cond = _END_COND_REGEX.search(line)
        if maybe_cond:
            del self._condition_stack[-1]

    def _check_for_define(self, line):
        maybe_var = _SET_REGEX.search(line)
        if maybe_var and (not self._condition_stack or self._condition_stack[-1]):
            key, value = maybe_var.groups()
            self._known_vars[key] = self._eval_value(value)

    def defines(self):
        return self._known_vars


def generate_version_header(pico_sdk_version_file, template, output):
    defines = RudimentaryCmakeParser(pico_sdk_version_file).defines()
    output.write(
        _EXPANSION_REGEX.sub(
            lambda val: str(defines.get(val.group(1))),
            template.read(),
        ).encode()
    )


if __name__ == "__main__":
    sys.exit(generate_version_header(**vars(_parse_args())))