/**
* Cache entry for file content
*/
interface CacheEntry {
content: string;
timestamp: number;
size: number;
}
/**
* LRU (Least Recently Used) cache for file contents
* Used to temporarily store file contents before modifications
*/
export class ContentCache {
private cache: Map<string, CacheEntry> = new Map();
private maxSize: number;
private currentSize = 0;
private ttl: number;
/**
* Create a new content cache
* @param maxSize Maximum cache size in bytes (default: 10MB)
* @param ttl Time to live in milliseconds (default: 5 minutes)
*/
constructor(maxSize: number = 10 * 1024 * 1024, ttl: number = 5 * 60 * 1000) {
this.maxSize = maxSize;
this.ttl = ttl;
// Periodically clean up expired entries
setInterval(() => this.cleanupExpired(), 60 * 1000); // Every minute
}
/**
* Get content from cache
* @param filePath File path
* @returns Content if found and not expired, undefined otherwise
*/
get(filePath: string): string | undefined {
const entry = this.cache.get(filePath);
if (!entry) return undefined;
// Check if expired
if (Date.now() - entry.timestamp > this.ttl) {
this.delete(filePath);
return undefined;
}
// Move to end (most recently used)
this.cache.delete(filePath);
this.cache.set(filePath, entry);
return entry.content;
}
/**
* Store content in cache
* @param filePath File path
* @param content File content
*/
set(filePath: string, content: string): void {
// Remove existing entry if present
if (this.cache.has(filePath)) {
this.delete(filePath);
}
const size = content.length * 2; // Approximate size in bytes (UTF-16)
// Make room if needed
while (this.currentSize + size > this.maxSize && this.cache.size > 0) {
// Remove least recently used (first item)
const firstKey = this.cache.keys().next().value;
if (firstKey) {
this.delete(firstKey);
}
}
// Add new entry
this.cache.set(filePath, {
content,
timestamp: Date.now(),
size
});
this.currentSize += size;
}
/**
* Delete an entry from cache
* @param filePath File path
*/
delete(filePath: string): boolean {
const entry = this.cache.get(filePath);
if (!entry) return false;
this.cache.delete(filePath);
this.currentSize -= entry.size;
return true;
}
/**
* Clear all entries from cache
*/
clear(): void {
this.cache.clear();
this.currentSize = 0;
}
/**
* Clean up expired entries
*/
private cleanupExpired(): void {
const now = Date.now();
const expiredKeys: string[] = [];
for (const [key, entry] of this.cache.entries()) {
if (now - entry.timestamp > this.ttl) {
expiredKeys.push(key);
}
}
for (const key of expiredKeys) {
this.delete(key);
}
}
/**
* Get cache statistics
*/
getStats(): {
size: number;
maxSize: number;
entries: number;
utilization: number;
} {
return {
size: this.currentSize,
maxSize: this.maxSize,
entries: this.cache.size,
utilization: this.currentSize / this.maxSize
};
}
}
