Occasionally throws FileNotFoundException by reading files after inserting to main disk cache concurrently · facebook/fresco#2382

(3 评论) (0 反应) (0 负责人)Java (17,072 star) (3,750 fork)batch import

bughelp wanted

描述

For more details please refer to this repo including a detailed README and a runnable Android app: https://github.com/JuniperPhoton/FrescoFileNotFoundBug

Description

This is an issue on this situation:

Massively and concurrently fetching images from network and insert them into disk cache immediately, and then read the files on the same thread.

By saying Massively and concurrently I mean doing the work on every 50ms, please refer to MainActivity for more details.

The issue is that sometimes it throws java.io.FileNotFoundException on reading saved files by opening a FileInputStream, even if the files do exist. The files can still be found using Android Studio's Device File Explorer can of course be opened.

Furthermore, if you try to open the file exported by content:// by other apps, or do a thread sleeping before accessing them, it will work.

Reproduction

Please refer to this repo: https://github.com/JuniperPhoton/FrescoFileNotFoundBug

Solution

Please refer to this repo: https://github.com/JuniperPhoton/FrescoFileNotFoundBug

Additional Information

Fresco version: 2.0.0
Platform version: No devices or OS version specified, tested on Android P/Q, Pixel 2 and OnePlus 7 Pro

贡献者指南

技术栈: javaandroid
领域: mobile
议题类型: bug
难度: 4
预计时间: half day
活动状态: stale
清晰度: mostly clear
前置要求: Android developmentJavaConcurrent programmingFresco library
新手友好度: 35
研究方向: Investigate the reproduction repository at https://github.com/JuniperPhoton/FrescoFileNotFoundBug to understand the concurrent disk cache insertion and reading pattern. Check the Fresco source code for disk cache synchronization, particularly in classes like DiskCache or DefaultDiskStorage. Look for potential race conditions where a file is still being written when read. Consider using thread sleeping as mentioned in the issue to verify timing.