Mini Shell

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import ConfigParser
import os

SECHEAD = 'asection'


class FakeSecHead(object):
    def __init__(self, fp):
        self.fp = fp
        self.sechead = '['+SECHEAD+']\n'

    def readline(self):
        if self.sechead:
            try: return self.sechead
            finally: self.sechead = None
        else: return self.fp.readline()



def load(path, case_sensitive=False):
    config = ConfigParser.ConfigParser()
    if case_sensitive:
        config.optionxform = str
    config.readfp(fp=FakeSecHead(open(path)), filename=path)
    return dict(config.items(section=SECHEAD))


cache = {}

def load_once(path, ignore_errors = False):
    """
    Read ini file once (cached) and return its content as dict
    """
    try:
        res = cache[path]
    except KeyError:
        try:
            res =  cache[path] = load(path)
        except (IOError, ConfigParser.Error):
            if not ignore_errors:
                raise
            res = cache[path] = {}
    return res


def change_settings(dict, path, tmp_path=None):
    if not tmp_path:
        tmp_path = path+".tmp"
    fin = open(path, 'r')
    fout = open(tmp_path, 'w')
    used_keys = []
    for line in fin:
        l = line.strip()
        if l and not l.startswith('#'):
            key, value = l.split('=', 1)
            key = key.strip()
            if key in dict:
                fout.write(key+'='+str(dict[key])+'\n')
                used_keys.append(key)
                continue
        fout.write(line)
    fin.close()
    for key in dict.keys():
        if key not in used_keys:
            fout.write(key+'='+str(dict[key])+'\n')
    fout.close()
    os.rename(tmp_path, path)