| # Copyright (c) 2023 The Regents of the University of California |
| # All rights reserved. |
| # |
| # Redistribution and use in source and binary forms, with or without |
| # modification, are permitted provided that the following conditions are |
| # met: redistributions of source code must retain the above copyright |
| # notice, this list of conditions and the following disclaimer; |
| # redistributions in binary form must reproduce the above copyright |
| # notice, this list of conditions and the following disclaimer in the |
| # documentation and/or other materials provided with the distribution; |
| # neither the name of the copyright holders nor the names of its |
| # contributors may be used to endorse or promote products derived from |
| # this software without specific prior written permission. |
| # |
| # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| from abc import ABC, abstractmethod |
| from typing import Dict, List |
| |
| |
| class Client(ABC): |
| def __init__(self): |
| self.__undo_stack = [] |
| self.__redo_stack = [] |
| self.__undo_limit = 10 |
| |
| @abstractmethod |
| def find_resource(self, query: Dict) -> Dict: |
| raise NotImplementedError |
| |
| @abstractmethod |
| def get_versions(self, query: Dict) -> List[Dict]: |
| raise NotImplementedError |
| |
| @abstractmethod |
| def update_resource(self, query: Dict) -> Dict: |
| raise NotImplementedError |
| |
| @abstractmethod |
| def check_resource_exists(self, query: Dict) -> Dict: |
| raise NotImplementedError |
| |
| @abstractmethod |
| def insert_resource(self, query: Dict) -> Dict: |
| raise NotImplementedError |
| |
| @abstractmethod |
| def delete_resource(self, query: Dict) -> Dict: |
| raise NotImplementedError |
| |
| @abstractmethod |
| def save_session(self) -> Dict: |
| raise NotImplementedError |
| |
| def undo_operation(self) -> Dict: |
| """ |
| This function undoes the last operation performed on the database. |
| """ |
| if len(self.__undo_stack) == 0: |
| return {"status": "Nothing to undo"} |
| operation = self.__undo_stack.pop() |
| print(operation) |
| if operation["operation"] == "insert": |
| self.delete_resource(operation["resource"]) |
| elif operation["operation"] == "delete": |
| self.insert_resource(operation["resource"]) |
| elif operation["operation"] == "update": |
| self.update_resource(operation["resource"]) |
| temp = operation["resource"]["resource"] |
| operation["resource"]["resource"] = operation["resource"][ |
| "original_resource" |
| ] |
| operation["resource"]["original_resource"] = temp |
| else: |
| raise Exception("Invalid Operation") |
| self.__redo_stack.append(operation) |
| return {"status": "Undone"} |
| |
| def redo_operation(self) -> Dict: |
| """ |
| This function redoes the last operation performed on the database. |
| """ |
| if len(self.__redo_stack) == 0: |
| return {"status": "No operations to redo"} |
| operation = self.__redo_stack.pop() |
| print(operation) |
| if operation["operation"] == "insert": |
| self.insert_resource(operation["resource"]) |
| elif operation["operation"] == "delete": |
| self.delete_resource(operation["resource"]) |
| elif operation["operation"] == "update": |
| self.update_resource(operation["resource"]) |
| temp = operation["resource"]["resource"] |
| operation["resource"]["resource"] = operation["resource"][ |
| "original_resource" |
| ] |
| operation["resource"]["original_resource"] = temp |
| else: |
| raise Exception("Invalid Operation") |
| self.__undo_stack.append(operation) |
| return {"status": "Redone"} |
| |
| def _add_to_stack(self, operation: Dict) -> Dict: |
| if len(self.__undo_stack) == self.__undo_limit: |
| self.__undo_stack.pop(0) |
| self.__undo_stack.append(operation) |
| self.__redo_stack.clear() |
| return {"status": "Added to stack"} |
| |
| def get_revision_status(self) -> Dict: |
| """ |
| This function saves the status of revision operations to a dictionary. |
| |
| The revision operations whose statuses are saved are undo and redo. |
| |
| If the stack of a given revision operation is empty, the status of |
| that operation is set to 1 else the status is set to 0. |
| |
| :return: A dictionary containing the status of revision operations. |
| """ |
| return { |
| "undo": 1 if len(self.__undo_stack) == 0 else 0, |
| "redo": 1 if len(self.__redo_stack) == 0 else 0, |
| } |