def insertWebsite(self, url, domain):
		'''增加一个网页,标记为未访问,并对相应的domain增加其入度'''
		cur = self.conn.cursor()
		cur.execute("SELECT 1 FROM Domains WHERE domain=?", (domain,))
		result = cur.fetchone()
		if not result:
			# 未有对应domain记录, 先创建domain, 把入度设为1
			if VERBOSE:
				print 'Spot Domain:',domain
			self.insertDomain(domain, indegree=1)
			cur.execute("SELECT did FROM Domains WHERE domain=?", (domain,))
			did = cur.fetchone()[0]
		else:
			did = result[0]
			# 对应的domain记录已经存在, 对其入度+1
			cur.execute("UPDATE Domains SET outdegree=outdegree+1 WHERE domain=?", (domain,))

		cur.execute("INSERT INTO Websites VALUES (NULL,?,?,NULL,0)", (did, url,))
		# 写入到文件
		self.conn.commit()
def get_current_branch(cls, location):
        """
        Return the current branch, or None if HEAD isn't at a branch
        (e.g. detached HEAD).
        """
        # git-symbolic-ref exits with empty stdout if "HEAD" is a detached
        # HEAD rather than a symbolic ref.  In addition, the -q causes the
        # command to exit with status code 1 instead of 128 in this case
        # and to suppress the message to stderr.
        args = ['symbolic-ref', '-q', 'HEAD']
        output = cls.run_command(
            args,
            extra_ok_returncodes=(1, ),
            show_stdout=False,
            stdout_only=True,
            cwd=location,
        )
        ref = output.strip()

        if ref.startswith('refs/heads/'):
            return ref[len('refs/heads/'):]

        return None