structs.py

structs.py

import re

class MakefileError(Exception):
    pass

class MakefileHeaderError(MakefileError):
    pass

class MakefileLinksError(MakefileError):
    pass

class MakefileNamingError(MakefileError):
    pass

class Goal:
    def __init__(self, name, parents):
        self.parents = parents
        self.commands = []
        self.name = name

    def add_command(self, command):
        self.commands.append(command.strip())

    @classmethod
    def parse_header(cls, string):
        if ':' not in string:
            raise HeaderError('Wrong goal header format, missing colon')
        name_str, parents_str = string.split(':')
        name = name_str.strip()
        if not re.match('^[a-zA-Z0-9+-]+$', name):
            raise MakefileNamingError('Wrong name: {}'.format(name))
        parents = parents_str.split()
        return cls(name, parents)

class Makefile:
    def __init__(self):
        self.goals = dict()

    def add_goal(self, goal):
        if goal.name in self.goals:
            raise MakefileNamingError('Found name duplication: {}'.format(goal.name))
        self.goals[goal.name] = goal

    def check_loops(self, node):
        def dfs(curr_node, visited):
            if curr_node.name in visited:
                raise MakefileLinksError('Found loop dependency')
            for parent in curr_node.parents:
                dfs(self.goals[parent], visited.union({curr_node.name}))
        dfs(node, set())

    def check(self):
        for goal in self.goals.values():
            for parent in goal.parents:
                if parent not in self.goals:
                    raise MakefileLinksError('Found broken dependency: {}'.format(parent))
        for goal in self.goals.values():
            self.check_loops(goal)