Merge pull request #823 from Jasonzhu1207/main

fix(perf): prevent memory growth in chat and export flows

electron/services/chatService.ts

@@ -349,6 +349,7 @@ class ChatService {
   private messageCursors: Map<string, { cursor: number; fetched: number; batchSize: number; startTime?: number; endTime?: number; ascending?: boolean; bufferedMessages?: any[] }> = new Map()
   private messageCursorMutex: boolean = false
   private readonly messageBatchDefault = 50
+  private readonly messageCursorSessionLimit = 8
   private avatarCache: Map<string, ContactCacheEntry>
   private readonly avatarCacheTtlMs = 10 * 60 * 1000
   private readonly defaultV1AesKey = 'cfcd208495d565ef'
@@ -673,6 +674,27 @@ class ChatService {
   /**
    * 关闭数据库连接
    */
+  private async closeMessageCursorBySession(sessionId: string): Promise<void> {
+    const state = this.messageCursors.get(sessionId)
+    if (!state) return
+    try {
+      await wcdbService.closeMessageCursor(state.cursor)
+    } catch (error) {
+      console.warn(`[ChatService] 关闭消息游标失败: ${sessionId}`, error)
+    } finally {
+      this.messageCursors.delete(sessionId)
+    }
+  }
+
+  private async trimMessageCursorStates(activeSessionId: string): Promise<void> {
+    if (this.messageCursors.size <= this.messageCursorSessionLimit) return
+    for (const [sessionId] of this.messageCursors) {
+      if (this.messageCursors.size <= this.messageCursorSessionLimit) break
+      if (sessionId === activeSessionId) continue
+      await this.closeMessageCursorBySession(sessionId)
+    }
+  }
+
   close(): void {
     try {
       for (const state of this.messageCursors.values()) {
@@ -1958,6 +1980,11 @@ class ChatService {
       }
 
       let state = this.messageCursors.get(sessionId)
+      if (state) {
+        // refresh insertion order so Map iteration approximates LRU
+        this.messageCursors.delete(sessionId)
+        this.messageCursors.set(sessionId, state)
+      }
 
       // 只在以下情况重新创建游标:
       // 1. 没有游标状态
@@ -1976,7 +2003,7 @@ class ChatService {
         // 关闭旧游标
         if (state) {
           try {
-            await wcdbService.closeMessageCursor(state.cursor)
+            await this.closeMessageCursorBySession(sessionId)
           } catch (e) {
             console.warn('[ChatService] 关闭旧游标失败:', e)
           }
@@ -1994,6 +2021,7 @@ class ChatService {
 
         state = { cursor: cursorResult.cursor, fetched: 0, batchSize, startTime, endTime, ascending }
         this.messageCursors.set(sessionId, state)
+        await this.trimMessageCursorStates(sessionId)
 
         // 如果需要跳过消息(offset > 0),逐批获取但不返回
         // 注意：仅在 offset === 0 时重建游标最安全；
@@ -2064,6 +2092,8 @@ class ChatService {
       const filtered = collected.messages || []
       const hasMore = collected.hasMore === true
       state.fetched += rawRowsConsumed
+      this.messageCursors.delete(sessionId)
+      this.messageCursors.set(sessionId, state)
       releaseMessageCursorMutex?.()
 
       this.messageCacheService.set(sessionId, filtered)

electron/services/httpService.ts

@@ -496,11 +496,20 @@ class HttpService {
     const contentType = mimeTypes[ext] || 'application/octet-stream'
 
     try {
-      const fileBuffer = fs.readFileSync(fullPath)
+      const stat = fs.statSync(fullPath)
       res.setHeader('Content-Type', contentType)
-      res.setHeader('Content-Length', fileBuffer.length)
+      res.setHeader('Content-Length', stat.size)
       res.writeHead(200)
-      res.end(fileBuffer)
+
+      const stream = fs.createReadStream(fullPath)
+      stream.on('error', () => {
+        if (!res.headersSent) {
+          this.sendError(res, 500, 'Failed to read media file')
+        } else {
+          try { res.destroy() } catch {}
+        }
+      })
+      stream.pipe(res)
     } catch (e) {
       this.sendError(res, 500, 'Failed to read media file')
     }

electron/services/messageCacheService.ts

@@ -12,6 +12,7 @@ export class MessageCacheService {
   private readonly cacheFilePath: string
   private cache: Record<string, SessionMessageCacheEntry> = {}
   private readonly sessionLimit = 150
+  private readonly maxSessionEntries = 48
 
   constructor(cacheBasePath?: string) {
     const basePath = cacheBasePath && cacheBasePath.trim().length > 0
@@ -36,6 +37,7 @@ export class MessageCacheService {
       const parsed = JSON.parse(raw)
       if (parsed && typeof parsed === 'object') {
         this.cache = parsed
+        this.pruneSessionEntries()
       }
     } catch (error) {
       console.error('MessageCacheService: 载入缓存失败', error)
@@ -43,6 +45,19 @@ export class MessageCacheService {
     }
   }
 
+  private pruneSessionEntries(): void {
+    const entries = Object.entries(this.cache || {})
+    if (entries.length <= this.maxSessionEntries) return
+
+    entries.sort((left, right) => {
+      const leftAt = Number(left[1]?.updatedAt || 0)
+      const rightAt = Number(right[1]?.updatedAt || 0)
+      return rightAt - leftAt
+    })
+
+    this.cache = Object.fromEntries(entries.slice(0, this.maxSessionEntries))
+  }
+
   get(sessionId: string): SessionMessageCacheEntry | undefined {
     return this.cache[sessionId]
   }
@@ -56,6 +71,7 @@ export class MessageCacheService {
       updatedAt: Date.now(),
       messages: trimmed
     }
+    this.pruneSessionEntries()
     this.persist()
   }
 

electron/services/snsService.ts

@@ -324,6 +324,9 @@ class SnsService {
     private configService: ConfigService
     private contactCache: ContactCacheService
     private imageCache = new Map<string, string>()
+    private imageCacheMeta = new Map<string, number>()
+    private readonly imageCacheTtlMs = 15 * 60 * 1000
+    private readonly imageCacheMaxEntries = 120
     private exportStatsCache: { totalPosts: number; totalFriends: number; myPosts: number | null; updatedAt: number } | null = null
     private userPostCountsCache: { counts: Record<string, number>; updatedAt: number } | null = null
     private readonly exportStatsCacheTtlMs = 5 * 60 * 1000
@@ -336,6 +339,38 @@ class SnsService {
         this.contactCache = new ContactCacheService(this.configService.get('cachePath') as string)
     }
 
+    clearMemoryCache(): void {
+        this.imageCache.clear()
+        this.imageCacheMeta.clear()
+    }
+
+    private pruneImageCache(now: number = Date.now()): void {
+        for (const [key, updatedAt] of this.imageCacheMeta.entries()) {
+            if (now - updatedAt > this.imageCacheTtlMs) {
+                this.imageCacheMeta.delete(key)
+                this.imageCache.delete(key)
+            }
+        }
+
+        while (this.imageCache.size > this.imageCacheMaxEntries) {
+            const oldestKey = this.imageCache.keys().next().value as string | undefined
+            if (!oldestKey) break
+            this.imageCache.delete(oldestKey)
+            this.imageCacheMeta.delete(oldestKey)
+        }
+    }
+
+    private rememberImageCache(cacheKey: string, dataUrl: string): void {
+        if (!cacheKey || !dataUrl) return
+        const now = Date.now()
+        if (this.imageCache.has(cacheKey)) {
+            this.imageCache.delete(cacheKey)
+        }
+        this.imageCache.set(cacheKey, dataUrl)
+        this.imageCacheMeta.set(cacheKey, now)
+        this.pruneImageCache(now)
+    }
+
     private toOptionalString(value: unknown): string | undefined {
         if (typeof value !== 'string') return undefined
         const trimmed = value.trim()
@@ -1239,20 +1274,27 @@ class SnsService {
         if (!url) return { success: false, error: 'url 不能为空' }
         const cacheKey = `${url}|${key ?? ''}`
 
-        if (this.imageCache.has(cacheKey)) {
-            const cachedDataUrl = this.imageCache.get(cacheKey) || ''
-            const base64Part = cachedDataUrl.split(',')[1] || ''
-            if (base64Part) {
-                try {
-                    const cachedBuf = Buffer.from(base64Part, 'base64')
-                    if (detectImageMime(cachedBuf, '').startsWith('image/')) {
-                        return { success: true, dataUrl: cachedDataUrl }
+        const cachedDataUrl = this.imageCache.get(cacheKey) || ''
+        if (cachedDataUrl) {
+            const cachedAt = this.imageCacheMeta.get(cacheKey) || 0
+            if (cachedAt > 0 && Date.now() - cachedAt <= this.imageCacheTtlMs) {
+                const base64Part = cachedDataUrl.split(',')[1] || ''
+                if (base64Part) {
+                    try {
+                        const cachedBuf = Buffer.from(base64Part, 'base64')
+                        if (detectImageMime(cachedBuf, '').startsWith('image/')) {
+                            this.imageCache.delete(cacheKey)
+                            this.imageCache.set(cacheKey, cachedDataUrl)
+                            this.imageCacheMeta.set(cacheKey, Date.now())
+                            return { success: true, dataUrl: cachedDataUrl }
+                        }
+                    } catch {
+                        // ignore and fall through to refetch
                     }
-                } catch {
-                    // ignore and fall through to refetch
                 }
             }
             this.imageCache.delete(cacheKey)
+            this.imageCacheMeta.delete(cacheKey)
         }
 
         const result = await this.fetchAndDecryptImage(url, key)
@@ -1269,7 +1311,7 @@ class SnsService {
                     return { success: false, error: '无效图片数据（可能密钥不匹配或缓存损坏）' }
                 }
                 const dataUrl = `data:${result.contentType};base64,${result.data.toString('base64')}`
-                this.imageCache.set(cacheKey, dataUrl)
+                this.rememberImageCache(cacheKey, dataUrl)
                 return { success: true, dataUrl }
             }
         }