chore: import upstream snapshot with attribution

apps/sim/lib/mcp/storage/memory-cache.ts

@@ -0,0 +1,103 @@
+import { createLogger } from '@sim/logger'
+import type { McpTool } from '@/lib/mcp/types'
+import { MCP_CONSTANTS } from '@/lib/mcp/utils'
+import type { McpCacheEntry, McpCacheStorageAdapter } from './adapter'
+
+const logger = createLogger('McpMemoryCache')
+
+export class MemoryMcpCache implements McpCacheStorageAdapter {
+  private cache = new Map<string, McpCacheEntry>()
+  private readonly maxCacheSize = MCP_CONSTANTS.MAX_CACHE_SIZE
+  private cleanupInterval: NodeJS.Timeout | null = null
+
+  constructor() {
+    this.startPeriodicCleanup()
+  }
+
+  private startPeriodicCleanup(): void {
+    this.cleanupInterval = setInterval(
+      () => {
+        this.cleanupExpiredEntries()
+      },
+      5 * 60 * 1000 // 5 minutes
+    )
+    // Don't keep Node process alive just for cache cleanup
+    this.cleanupInterval.unref()
+  }
+
+  private cleanupExpiredEntries(): void {
+    const now = Date.now()
+    const expiredKeys: string[] = []
+
+    this.cache.forEach((entry, key) => {
+      if (entry.expiry <= now) {
+        expiredKeys.push(key)
+      }
+    })
+
+    expiredKeys.forEach((key) => this.cache.delete(key))
+
+    if (expiredKeys.length > 0) {
+      logger.debug(`Cleaned up ${expiredKeys.length} expired cache entries`)
+    }
+  }
+
+  private evictIfNeeded(): void {
+    if (this.cache.size <= this.maxCacheSize) {
+      return
+    }
+
+    // Evict oldest entries (by insertion order - Map maintains order)
+    const entriesToRemove = this.cache.size - this.maxCacheSize
+    const keys = Array.from(this.cache.keys()).slice(0, entriesToRemove)
+    keys.forEach((key) => this.cache.delete(key))
+
+    logger.debug(`Evicted ${entriesToRemove} cache entries`)
+  }
+
+  async get(key: string): Promise<McpCacheEntry | null> {
+    const entry = this.cache.get(key)
+    const now = Date.now()
+
+    if (!entry || entry.expiry <= now) {
+      if (entry) {
+        this.cache.delete(key)
+      }
+      return null
+    }
+
+    // Return copy to prevent caller from mutating cache
+    return {
+      tools: entry.tools,
+      expiry: entry.expiry,
+    }
+  }
+
+  async set(key: string, tools: McpTool[], ttlMs: number): Promise<void> {
+    const now = Date.now()
+    const entry: McpCacheEntry = {
+      tools,
+      expiry: now + ttlMs,
+    }
+
+    this.cache.set(key, entry)
+    this.evictIfNeeded()
+  }
+
+  async delete(key: string): Promise<void> {
+    this.cache.delete(key)
+  }
+
+  async clear(): Promise<void> {
+    this.cache.clear()
+  }
+
+  dispose(): void {
+    if (this.cleanupInterval) {
+      clearInterval(this.cleanupInterval)
+      this.cleanupInterval = null
+    }
+    this.cache.clear()
+    logger.info('Memory cache disposed')
+  }
+}