Prompt
Help with file processing security tasks according to the goals and materials below. [input] Goals and usage situations: I want to clear a blockage in my file handling security and decide my next course of action. Resources to review: Upload/download implementation Conditions and Constraints: Please proceed based on the provided data, and mark any missing facts as requiring confirmation. Previous attempts and records: This is my first attempt. Please proceed from the parts that can be confirmed in the current data. [Key points to check in this topic] Distinguish between path, file type, size, access rights, and executable. [Results to be created this time] Find branches, abstractions, and state that are not needed to meet the current need. Check the rationale for removal and impact on callers, and suggest simplification in small units. Convert it to an explainable structure while preserving existing behavior and tests. [Working Principle] Give priority to facts confirmed in the current environment and provided code. Don't create APIs/files/tests that don't exist. Treat sensitive values as hidden examples and leave unexecuted tasks as unexecuted. If there is no input that will change the results, ask only the necessary questions first and proceed with the parts that can be confirmed with data. [Completion criteria] Ensure complexity is reduced without changing externally observable behavior. Distinguish between the basis for the outcome, remaining uncertainties, and next actions, and mark only what has actually been confirmed as complete.