代码的坏味道:控制结构嵌套太深

重构前的代码

    def newPrj(self,db,userId,prjName,password,privacy,intro='',status='active'):
        s = ''
        flag = False
        prjId=0
        
        try:
            t = db.transaction()
            if privacy == 'public' and len(password) < 1:
                return '{"result":"error","message":"公开访问并且不设置密码，任何人都可以加入您的项目"}'
            
            folderId,deep = tn.newFolder(db,prjName,userId,0,0)
            if folderId != 0:
                prjId = db.insert('Project',folderId=folderId,userId=userId,projectName=prjName,
                    password=password,privacy=privacy,intro=intro,status=status,
                    createTime=str(datetime.datetime.today()),revision=util.new_revision(db,userId))
                db.update("Category",where="catId=$folderId",projectId=prjId,deep=-1,vars=locals())
                
                import json
                from role import RoleMgr
                roleMgr = RoleMgr()
                s = roleMgr.newRole(db,"项目用户",prjId)
                dict = json.JSONDecoder().decode(s)
                if dict['result'] == 'ok':
                    roleId = int(dict['roleId'])
                    if roleMgr.bindPermission(db,roleId,folderId,read=1,write=0) == True:
                        flag = True
                        s = '{"result":"ok","prjId": "%d"}' %(int(prjId))
                    else:
                        s = '{"result":"error","message":"预置项目角色权限失败"}'
                else:
                    s = '{"result":"error","message":"预置项目角色失败"}'
            else:
                s = '{"result":"error","message":"存在同名文件夹"}'
            
            if flag == True:
                t.commit()
            else:
                t.rollback()
                
            return s
        
        except:
            t.rollback()

重构后的代码

def newPrj(db,userId,projectName,password,privacy,intro,status='active'):
    try:
        t = db.transaction()
        projectName = projectName.lstrip().rstrip()
        if not _checkName(projectName):
            t.rollback()
            return (False,"项目名不合法")
        folderId,deep = tn.newFolder(db,projectName,userId,0,0)
        if folderId == 0:
            t.rollback()
            return (False,"创建项目根目录失败")
        projectId = _insert(db,projectName,folderId,userId,password,privacy,intro,status)
        if projectId == 0:
            t.rollback()
            return (False,"创建项目失败")
        if folder.setRootFolder(db,folderId,projectId) == False:
            t.rollback()
            return (False,"设置目录失败")
        if _preSetRole(db,userId,folderId,projectId) == False:
            t.rollback()
            return (False,"创建默认角色失败")
        if _preSetFolder(db,userId,folderId) == False:
            t.rollback()
            return (False,"创建项目目录失败")

        t.commit()
        return (True,projectId)
    except:
        t.rollback()
        raise