feat: add document OCR and offline model archives

src/main/document-ocr-broker.ts

@@ -0,0 +1,131 @@
+import type { BrowserWindow } from 'electron'
+import { ipcChannels } from '../shared/ipc-channels'
+import {
+  documentOcrFailureSchema,
+  documentOcrRequestSchema,
+  documentOcrResultSchema,
+  type DocumentOcrRequest,
+  type DocumentOcrResult
+} from '../shared/document-parsing-contracts'
+
+type PendingRequest = {
+  resolve: (result: DocumentOcrResult) => void
+  reject: (error: Error) => void
+  timer: ReturnType<typeof setTimeout>
+  detachAbort: () => void
+}
+
+const maximumPendingRequests = 4
+const maximumTotalTimeoutMs = 10 * 60 * 1_000
+
+export class DocumentOcrBroker {
+  private readonly pending = new Map<string, PendingRequest>()
+  private disposed = false
+
+  constructor(private readonly window: BrowserWindow) {}
+
+  recognize(
+    input: Omit<DocumentOcrRequest, 'requestId'>,
+    signal?: AbortSignal
+  ): Promise<DocumentOcrResult> {
+    if (this.disposed || this.window.isDestroyed()) {
+      throw new Error('OCR 渲染服务不可用')
+    }
+    if (this.pending.size >= maximumPendingRequests) {
+      throw new Error('OCR 任务过多，请稍后重试')
+    }
+    const request = documentOcrRequestSchema.parse({
+      ...input,
+      requestId: crypto.randomUUID()
+    })
+    if (signal?.aborted) {
+      throw new Error('OCR 解析已取消')
+    }
+    const timeoutMs = Math.min(
+      maximumTotalTimeoutMs,
+      Math.max(
+        request.pageTimeoutSeconds * 1_000,
+        request.pageTimeoutSeconds *
+          request.maximumPages *
+          1_000
+      )
+    )
+    return new Promise<DocumentOcrResult>((resolve, reject) => {
+      const cancel = (message: string): void => {
+        const pending = this.pending.get(request.requestId)
+        if (!pending) {
+          return
+        }
+        clearTimeout(pending.timer)
+        pending.detachAbort()
+        this.pending.delete(request.requestId)
+        this.window.webContents.send(
+          ipcChannels.documentParsingOcrCancel,
+          request.requestId
+        )
+        reject(new Error(message))
+      }
+      const timer = setTimeout(() => {
+        cancel('OCR 解析超时')
+      }, timeoutMs)
+      const onAbort = (): void => cancel('OCR 解析已取消')
+      signal?.addEventListener('abort', onAbort, { once: true })
+      this.pending.set(request.requestId, {
+        resolve,
+        reject,
+        timer,
+        detachAbort: () =>
+          signal?.removeEventListener('abort', onAbort)
+      })
+      if (signal?.aborted) {
+        cancel('OCR 解析已取消')
+        return
+      }
+      this.window.webContents.send(
+        ipcChannels.documentParsingOcrRequest,
+        request
+      )
+    })
+  }
+
+  respond(input: unknown): void {
+    const result = documentOcrResultSchema.safeParse(input)
+    const failure = result.success
+      ? undefined
+      : documentOcrFailureSchema.safeParse(input)
+    const requestId = result.success
+      ? result.data.requestId
+      : failure?.success
+        ? failure.data.requestId
+        : undefined
+    if (!requestId) {
+      throw new Error('OCR 响应无效')
+    }
+    const pending = this.pending.get(requestId)
+    if (!pending) {
+      return
+    }
+    clearTimeout(pending.timer)
+    pending.detachAbort()
+    this.pending.delete(requestId)
+    if (result.success) {
+      pending.resolve(result.data)
+    } else {
+      if (!failure?.success) {
+        pending.reject(new Error('OCR 响应无效'))
+        return
+      }
+      pending.reject(new Error(failure.data.error))
+    }
+  }
+
+  dispose(): void {
+    this.disposed = true
+    for (const pending of this.pending.values()) {
+      clearTimeout(pending.timer)
+      pending.detachAbort()
+      pending.reject(new Error('OCR 解析已取消'))
+    }
+    this.pending.clear()
+  }
+}