Use BufferedOutputStream when writing the Zip file to improve performance
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When not using STORED entries use a BufferedOutputStream to avoid lots of small writes to the file system. Testing this with a 300mb jar build I see the total build time going from 40s to 30s. Note that it is not possible to do this with STORED entries as the implementation requires a RandomAccessFile to update the CRC after write.
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BufferedOutputStream when writing the Zip file to improve performance
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Pull Request Overview
This PR improves ZIP file creation performance by using BufferedOutputStream for non-STORED compression methods. The change conditionally wraps the file output stream with a buffer to reduce system call overhead during ZIP file writing.
Key changes:
- Modified
DefaultZipCompressorto conditionally useBufferedOutputStreambased on compression method - Added changelog entry documenting the performance improvement
Reviewed Changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
| DefaultZipCompressor.groovy | Adds conditional buffering logic to improve ZIP writing performance for non-STORED entries |
| README.md | Documents the performance improvement in the changelog |
src/main/groovy/com/github/jengelman/gradle/plugins/shadow/internal/DefaultZipCompressor.groovy
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src/main/groovy/com/github/jengelman/gradle/plugins/shadow/internal/DefaultZipCompressor.groovy
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When not using STORED entries use a BufferedOutputStream to avoid lots of small writes to the file system.
Testing this with a 300mb jar build I see the total build time going from 40s to 30s.
Note that it is not possible to do this with STORED entries as the implementation requires a RandomAccessFile to update the CRC after write.