新的提交

electron/services/imagePreloadService.ts

@@ -0,0 +1,66 @@
+import { imageDecryptService } from './imageDecryptService'
+
+type PreloadImagePayload = {
+  sessionId?: string
+  imageMd5?: string
+  imageDatName?: string
+}
+
+type PreloadTask = PreloadImagePayload & {
+  key: string
+}
+
+export class ImagePreloadService {
+  private queue: PreloadTask[] = []
+  private pending = new Set<string>()
+  private active = 0
+  private readonly maxConcurrent = 2
+
+  enqueue(payloads: PreloadImagePayload[]): void {
+    if (!Array.isArray(payloads) || payloads.length === 0) return
+    for (const payload of payloads) {
+      const cacheKey = payload.imageMd5 || payload.imageDatName
+      if (!cacheKey) continue
+      const key = `${payload.sessionId || 'unknown'}|${cacheKey}`
+      if (this.pending.has(key)) continue
+      this.pending.add(key)
+      this.queue.push({ ...payload, key })
+    }
+    this.processQueue()
+  }
+
+  private processQueue(): void {
+    while (this.active < this.maxConcurrent && this.queue.length > 0) {
+      const task = this.queue.shift()
+      if (!task) return
+      this.active += 1
+      void this.handleTask(task).finally(() => {
+        this.active -= 1
+        this.pending.delete(task.key)
+        this.processQueue()
+      })
+    }
+  }
+
+  private async handleTask(task: PreloadTask): Promise<void> {
+    const cacheKey = task.imageMd5 || task.imageDatName
+    if (!cacheKey) return
+    try {
+      const cached = await imageDecryptService.resolveCachedImage({
+        sessionId: task.sessionId,
+        imageMd5: task.imageMd5,
+        imageDatName: task.imageDatName
+      })
+      if (cached.success) return
+      await imageDecryptService.decryptImage({
+        sessionId: task.sessionId,
+        imageMd5: task.imageMd5,
+        imageDatName: task.imageDatName
+      })
+    } catch {
+      // ignore preload failures
+    }
+  }
+}
+
+export const imagePreloadService = new ImagePreloadService()