Save form data in XFA datasets when pdf is a mix of acroforms and xfa (#12344)

* Move display/xml_parser.js in shared to use it in worker

* Save form data in XFA datasets when pdf is a mix of acroforms and xfa

Co-authored-by: Brendan Dahl <brendan.dahl@gmail.com>

src/core/writer.js

@@ -14,8 +14,14 @@
  */
 /* eslint no-var: error */
 
-import { bytesToString, escapeString } from "../shared/util.js";
+import {
+  bytesToString,
+  escapeString,
+  parseXFAPath,
+  warn,
+} from "../shared/util.js";
 import { Dict, isDict, isName, isRef, isStream, Name } from "./primitives.js";
+import { SimpleDOMNode, SimpleXMLParser } from "../shared/xml_parser.js";
 import { calculateMD5 } from "./crypto.js";
 
 function writeDict(dict, buffer, transform) {
@@ -123,7 +129,55 @@ function computeMD5(filesize, xrefInfo) {
   return bytesToString(calculateMD5(array));
 }
 
-function incrementalUpdate(originalData, xrefInfo, newRefs) {
+function updateXFA(datasetsRef, newRefs, xref) {
+  if (datasetsRef === null || xref === null) {
+    return;
+  }
+  const datasets = xref.fetchIfRef(datasetsRef);
+  const str = bytesToString(datasets.getBytes());
+  const xml = new SimpleXMLParser(/* hasAttributes */ true).parseFromString(
+    str
+  );
+
+  for (const { xfa } of newRefs) {
+    if (!xfa) {
+      continue;
+    }
+    const { path, value } = xfa;
+    if (!path) {
+      continue;
+    }
+    const node = xml.documentElement.searchNode(parseXFAPath(path), 0);
+    if (node) {
+      node.childNodes = [new SimpleDOMNode("#text", value)];
+    } else {
+      warn(`Node not found for path: ${path}`);
+    }
+  }
+  const buffer = [];
+  xml.documentElement.dump(buffer);
+  let updatedXml = buffer.join("");
+
+  const encrypt = xref.encrypt;
+  if (encrypt) {
+    const transform = encrypt.createCipherTransform(
+      datasetsRef.num,
+      datasetsRef.gen
+    );
+    updatedXml = transform.encryptString(updatedXml);
+  }
+  const data =
+    `${datasetsRef.num} ${datasetsRef.gen} obj\n` +
+    `<< /Type /EmbeddedFile /Length ${updatedXml.length}>>\nstream\n` +
+    updatedXml +
+    "\nendstream\nendobj\n";
+
+  newRefs.push({ ref: datasetsRef, data });
+}
+
+function incrementalUpdate(originalData, xrefInfo, newRefs, xref, datasetsRef) {
+  updateXFA(datasetsRef, newRefs, xref);
+
   const newXref = new Dict(null);
   const refForXrefTable = xrefInfo.newRef;