fix: prevent load multiple pdf worker when use multiple pdf files

Signed-off-by: Vitor Mattos <1079143+vitormattos@users.noreply.github.com>

Author: vitormattos

src/utils/asyncReader.js

@@ -1,11 +1,20 @@
 // SPDX-FileCopyrightText: 2026 LibreCode coop and contributors
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
-import { getDocument, GlobalWorkerOptions } from 'pdfjs-dist'
+import { getDocument, GlobalWorkerOptions, PDFWorker } from 'pdfjs-dist'
 import pdfWorkerCode from 'pdfjs-dist/build/pdf.worker.min.mjs'
 
 GlobalWorkerOptions.workerSrc = pdfWorkerCode
 
+let sharedWorker = null
+
+function getSharedWorker() {
+  if (!sharedWorker) {
+    sharedWorker = new PDFWorker({ name: 'libresign-pdf-worker' })
+  }
+  return sharedWorker
+}
+
 export function setWorkerPath(path) {
   GlobalWorkerOptions.workerSrc = path
 }
@@ -20,5 +29,16 @@ export function readAsArrayBuffer(file) {
 }
 
 export function readAsPDF(file) {
-  return getDocument(file).promise
+  const worker = getSharedWorker()
+  const isArrayBuffer = file instanceof ArrayBuffer
+  const isView = ArrayBuffer.isView(file)
+  const isBlob = typeof Blob !== 'undefined' && file instanceof Blob
+
+  if (file && typeof file === 'object' && !isArrayBuffer && !isView && !isBlob) {
+    return getDocument({ ...file, worker }).promise
+  }
+  if (typeof file === 'string') {
+    return getDocument({ url: file, worker }).promise
+  }
+  return getDocument({ data: file, worker }).promise
 }