checker.py

import ast
from collections import namedtuple
import os.path
import sys
import tempfile

try:
    # as plugin
    from .pep8 import pep8
    from .pyflakes import checker
except (SystemError, ValueError):
    # external process
    from pep8 import pep8
    from pyflakes import checker

Problem = namedtuple('Problem', 'level lineno offset message')


class Pep8Report(pep8.BaseReport):

    def __init__(self, *args, **kwargs):
        self.problems = []
        if sys.version_info[0] >= 3:
            super().__init__(*args, **kwargs)
        else:
            super(Pep8Report, self).__init__(*args, **kwargs)

    def error(self, line_number, offset, text, check):
        code = text[:4]
        if self._ignore_code(code):
            return
        level = 'error' if text.startswith('E') else 'warn'
        self.problems.append(Problem(level, line_number, offset, text))


def get_problems(source, filename):
    flakes = get_flakes(source, filename)
    style_problems = get_style_problems(source, filename)
    return list(flakes) + list(style_problems)


def get_flakes(source, filename):
    try:
        tree = ast.parse(source, filename, "exec")
    except SyntaxError:
        value = sys.exc_info()[1]
        msg = value.args[0]
        yield Problem('error', value.lineno, value.offset, msg)
    else:
        results = checker.Checker(tree, filename)
        for m in results.messages:
            yield Problem('warn', m.lineno, m.col,
                          m.message % m.message_args)


def get_style_problems(source, filename):
    config, _args = pep8.process_options([filename], config_file=True)
    config = dict(config.__dict__, reporter=Pep8Report)
    guide = pep8.StyleGuide(**config)
    lines = source.splitlines(True)
    checker = pep8.Checker(filename, lines, guide.options)
    checker.check_all()
    return checker.report.problems


def get_external(source, filename, executable):
    import json
    import subprocess
    tf = tempfile.NamedTemporaryFile(delete=False)
    tf.write(source.encode('utf-8'))
    tf.close()
    try:
        output = subprocess.check_output([executable,
                                          os.path.dirname(__file__),
                                          tf.name, filename])
    finally:
        os.unlink(tf.name)
    problems = json.loads(output.decode('utf-8'))
    problems = [Problem(*p) for p in problems]
    return problems