Taskmaster

/** * Cache Manager * Handles all caching logic with LRU eviction and analytics */ import type { ExtensionLogger } from '../../logger'; import type { CacheAnalytics, CacheConfig, CacheEntry } from '../types'; export class CacheManager { private cache = new Map<string, CacheEntry>(); private analytics: CacheAnalytics = { hits: 0, misses: 0, evictions: 0, refreshes: 0, totalSize: 0, averageAccessTime: 0, hitRate: 0 }; private backgroundRefreshTimer?: NodeJS.Timeout; constructor( private config: CacheConfig & { cacheDuration: number }, private logger: ExtensionLogger ) { if (config.enableBackgroundRefresh) { this.initializeBackgroundRefresh(); } } /** * Get data from cache if not expired */ get(key: string): any { const startTime = Date.now(); const cached = this.cache.get(key); if (cached) { const isExpired = Date.now() - cached.timestamp >= (cached.ttl || this.config.cacheDuration); if (!isExpired) { // Update access statistics cached.accessCount++; cached.lastAccessed = Date.now(); if (this.config.enableAnalytics) { this.analytics.hits++; } const accessTime = Date.now() - startTime; this.logger.debug( `Cache hit for ${key} (${accessTime}ms, ${cached.accessCount} accesses)` ); return cached.data; } else { // Remove expired entry this.cache.delete(key); this.logger.debug(`Cache entry expired and removed: ${key}`); } } if (this.config.enableAnalytics) { this.analytics.misses++; } this.logger.debug(`Cache miss for ${key}`); return null; } /** * Set data in cache with LRU eviction */ set( key: string, data: any, options?: { ttl?: number; tags?: string[] } ): void { const now = Date.now(); const dataSize = this.estimateDataSize(data); // Create cache entry const entry: CacheEntry = { data, timestamp: now, accessCount: 1, lastAccessed: now, size: dataSize, ttl: options?.ttl, tags: options?.tags || [key.split('_')[0]] }; // Check if we need to evict entries (LRU strategy) if (this.cache.size >= this.config.maxSize) { this.evictLRUEntries(Math.max(1, Math.floor(this.config.maxSize * 0.1))); } this.cache.set(key, entry); this.logger.debug( `Cached data for ${key} (size: ${dataSize} bytes, TTL: ${entry.ttl || this.config.cacheDuration}ms)` ); // Trigger prefetch if enabled if (this.config.enablePrefetch) { this.scheduleRelatedDataPrefetch(key, data); } } /** * Clear cache entries matching a pattern */ clearPattern(pattern: string): void { let evictedCount = 0; for (const key of this.cache.keys()) { if (key.includes(pattern)) { this.cache.delete(key); evictedCount++; } } if (evictedCount > 0) { this.analytics.evictions += evictedCount; this.logger.debug( `Evicted ${evictedCount} cache entries matching pattern: ${pattern}` ); } } /** * Clear all cached data */ clear(): void { this.cache.clear(); this.resetAnalytics(); } /** * Get cache analytics */ getAnalytics(): CacheAnalytics { this.updateAnalytics(); return { ...this.analytics }; } /** * Get frequently accessed entries for background refresh */ getRefreshCandidates(): Array<[string, CacheEntry]> { return Array.from(this.cache.entries()) .filter(([key, entry]) => { const age = Date.now() - entry.timestamp; const isNearExpiration = age > this.config.cacheDuration * 0.7; const isFrequentlyAccessed = entry.accessCount >= 3; return ( isNearExpiration && isFrequentlyAccessed && key.includes('get_tasks') ); }) .sort((a, b) => b[1].accessCount - a[1].accessCount) .slice(0, 5); } /** * Update refresh count for analytics */ incrementRefreshes(): void { this.analytics.refreshes++; } /** * Cleanup resources */ destroy(): void { if (this.backgroundRefreshTimer) { clearInterval(this.backgroundRefreshTimer); this.backgroundRefreshTimer = undefined; } this.clear(); } private initializeBackgroundRefresh(): void { if (this.backgroundRefreshTimer) { clearInterval(this.backgroundRefreshTimer); } const interval = this.config.refreshInterval; this.backgroundRefreshTimer = setInterval(() => { // Background refresh is handled by the main API class // This just maintains the timer }, interval); this.logger.debug( `Cache background refresh initialized with ${interval}ms interval` ); } private evictLRUEntries(count: number): void { const entries = Array.from(this.cache.entries()) .sort((a, b) => a[1].lastAccessed - b[1].lastAccessed) .slice(0, count); for (const [key] of entries) { this.cache.delete(key); this.analytics.evictions++; } if (entries.length > 0) { this.logger.debug(`Evicted ${entries.length} LRU cache entries`); } } private estimateDataSize(data: any): number { try { return JSON.stringify(data).length * 2; // Rough estimate } catch { return 1000; // Default fallback } } private scheduleRelatedDataPrefetch(key: string, data: any): void { if (key.includes('get_tasks') && Array.isArray(data)) { this.logger.debug( `Scheduled prefetch for ${data.length} tasks related to ${key}` ); } } private resetAnalytics(): void { this.analytics = { hits: 0, misses: 0, evictions: 0, refreshes: 0, totalSize: 0, averageAccessTime: 0, hitRate: 0 }; } private updateAnalytics(): void { const total = this.analytics.hits + this.analytics.misses; this.analytics.hitRate = total > 0 ? this.analytics.hits / total : 0; this.analytics.totalSize = this.cache.size; if (this.cache.size > 0) { const totalAccessTime = Array.from(this.cache.values()).reduce( (sum, entry) => sum + (entry.lastAccessed - entry.timestamp), 0 ); this.analytics.averageAccessTime = totalAccessTime / this.cache.size; } } }