perf: Implement streaming XML parsing and improve file upload collision handling #16236
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- Add StreamingReadFolderRemoteOperation for memory-efficient folder reading using SAX parser - Add PropFindSaxHandler for streaming XML parsing of PROPFIND responses - Prevent OutOfMemoryError for folders with thousands of files by avoiding full XML loading - Integrate streaming parser into RefreshFolderOperation with fallback to legacy method - Add batch processing for large folders (500 files per batch) in FileDataStorageManager - Improve logging levels and add thread name tracking for better debugging Signed-off-by: dmiales <[email protected]>
Problem: Users with large photo and video libraries (5000+ files per folder) experience severe performance issues and OutOfMemoryError (OOM) crashes when opening folders. The application receives a massive XML file from the server and attempts to parse it entirely in memory, causing: - Application freezes and lagging (observed on Samsung S23+) - OOM errors during XML parsing - OOM errors in background synchronization processes - Data loss due to crashes during sync operations Solution: Rewrote the parsing block from the old ownCloud approach to a new streaming parser implementation. Additionally implemented batch processing for folders. This eliminates OOM errors and significantly improves performance and stability, even with 20,000+ photos and videos in a single folder. Implementation details: - Add StreamingReadFolderRemoteOperation for memory-efficient folder reading using SAX parser - Add PropFindSaxHandler for streaming XML parsing of PROPFIND responses - Prevent OutOfMemoryError for folders with thousands of files by avoiding full XML loading - Integrate streaming parser into RefreshFolderOperation with fallback to legacy method - Add batch processing for large folders (500 files per batch) in FileDataStorageManager - Improve file upload collision handling in UploadFileOperation - Add content comparison for non-encrypted files when SKIP policy is used - Report SYNC_CONFLICT when file with same name has different content - Preserve old behavior for encrypted files and edge cases - Improve logging levels and add thread name tracking for better debugging Signed-off-by: dmiales <[email protected]>
- Replace inefficient trim().isEmpty() with isBlank() method - Extract string literals to constants (LOG_EQUALS_QUOTE, UNKNOWN_PATH) - Add size limits to StringBuilder to prevent memory leaks - Combine nested if statements for better code style Signed-off-by: dmiales <[email protected]>
- Remove empty debug if blocks - Remove DEBUG_XML constant and related debug logging - Remove all Log_OC.d() debug statements - Remove unused UNKNOWN_PATH constant Signed-off-by: dmiales <[email protected]>
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- Combine nested if statements for better code style - Remove hard size limit on StringBuilder, rely on periodic cleanup - Add comments explaining memory safety of StringBuilder usage - Optimize initial StringBuilder capacity to 512 bytes Signed-off-by: dmiales <[email protected]>
- Add @SuppressWarnings for PMD and SonarQube patterns - Add @SuppressFBWarnings for SpotBugs - Add codacy-disable comments - StringBuilder fields are safe: cleared after each XML element and capacity trimmed periodically Signed-off-by: dmiales <[email protected]>
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Problem:
Users with large photo and video libraries (5000+ files per folder) experience severe performance issues and OutOfMemoryError (OOM) crashes when opening folders. The application receives a massive XML file from the server and attempts to parse it entirely in memory, causing:
Solution:
Rewrote the parsing block from the old ownCloud approach to a new streaming parser implementation. Additionally implemented batch processing for folders. This eliminates OOM errors and significantly improves performance and stability, even with 20,000+ photos and videos in a single folder.
Implementation details: