PERFORMANCE_FIXES.md

Performance Optimization Implementation Log

Critical Fixes Being Applied

Fix #1: DeviceCardView Side Effects

Problem: calculateConfidenceAndRecordHistory() called on every view render Solution:

• Add @Published deviceConfidenceCache to NetworkDiscoveryManager
• Calculate confidence once when device is added
• Views read from cache only
• Update cache when device data changes

Fix #2: Bounded Device Array

Problem: discoveredDevices array grows unbounded Solution:

• Add maxDevices = 500 constant
• Implement LRU eviction when limit reached
• Evict oldest discovered devices first

Fix #3: Network Connection Optimization

Problem: Opening NWConnection for every device just to get IP Solution:

• Extract host/port from NWBrowser.Result.endpoint directly
• Remove wasteful connection creation
• Keep fallback timeout for edge cases

Fix #4: Retain Cycle in NWConnection

Problem: Connection handler captures connection strongly Solution:

• Change to [weak self, weak connection] in all handlers
• Prevent memory leaks

Fix #5: ScannerView Filter Performance

Problem: filteredDevices recomputed on every render Solution:

• Move to ViewModel with cached result
• Invalidate cache only on actual data changes

Implementation Status

• Added deviceConfidenceCache to NetworkDiscoveryManager
• Added maxDevices constant
• Implement addDevice() helper with caching and bounds
• Fix NWConnection retain cycles
• Implement LRU eviction for bounded arrays
• Update DeviceCardView to use cache
• Fix tuple naming issue in getCachedConfidence
• Add NetworkDiscoveryManagerTests (14 tests)
• Add SecureStorageManagerTests (25 tests)
• Add InputValidatorTests (45 tests)
• Add LoggingManagerTests (30 tests)
• Remove wasteful connection creation (OPTIONAL)
• Create ScannerViewModel (OPTIONAL)
• Add remaining 4 test files
• Run all tests and verify coverage