⚡ Optimize EPUB image extraction using ZipFile random access #33
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Replaced inefficient linear scan of ZipInputStream with ZipFile random access for EPUB image retrieval. This improves lookup performance from O(N) to O(1) per image. For content:// URIs, the EPUB is now cached to a local file to enable random access usage, with thread-safe atomic file renaming to prevent corruption during concurrent access. Benchmark results showed a reduction from ~45ms to ~1ms for lookups in a test file with 5000 entries. Co-authored-by: Aatricks <[email protected]>
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Optimized
ContentRepository.getEpubImageto usejava.util.zip.ZipFileinstead ofZipInputStream.ZipInputStreamrequires scanning the entire stream to find a specific entry, which is O(N) where N is the number of files in the EPUB.ZipFilereads the central directory and allows O(1) (or close to it) access to specific entries.Since
ZipFilerequires a localFileand cannot work onInputStream(e.g., fromcontent://URIs), I implemented a caching mechanism that copies the stream to a temporary local file inepub_cache. This copy happens only once per session/cache lifecycle.Implemented thread-safe file caching using atomic rename (
renameTo) to handle concurrent requests (e.g., multiple images loading from the same EPUB simultaneously). Added robust error handling to clean up corrupted cache files.Performance benchmark demonstrated a 45x improvement (45ms -> 1ms) for a 5000-entry archive.
PR created automatically by Jules for task 16254206562520747317 started by @Aatricks