def robotsrulesetOfDomain(self, domain):
		'''检查domain是否在数据库中,
			否 --> (False, None)
			是 --> (True, 数据库中存储的robots.txt内容)
		'''
		exist = False
		cur = self.conn.cursor()
		# 是否存在
		cur.execute("SELECT 1 FROM Domains WHERE domain=?", (domain,))
		if cur.fetchone() :
			exist = True
		# 存在的话,结果是什么
		cur.execute("SELECT rules FROM Domains,Rulesets "
			"WHERE domain=? AND Domains.did=Rulesets.did"
			,(domain,) )
		ruleset = cur.fetchone()
		return (exist, ruleset)
def _files(self):
        if self.isexact():
            m1, m2 = self._m1, self._m2
            if not m1.isexact():
                m1, m2 = m2, m1
            return [f for f in m1.files() if m2(f)]
        # It neither m1 nor m2 is an exact matcher, we can't easily intersect
        # the set of files, because their files() are not always files. For
        # example, if intersecting a matcher "-I glob:foo.txt" with matcher of
        # "path:dir2", we don't want to remove "dir2" from the set.
        return self._m1.files() + self._m2.files()