Merge pull request #16718 from calixteman/bug1844572

Don't replace Acroform dictionary if nothing has changed when saving (bug 1844572)

src/core/worker.js

@@ -544,6 +544,7 @@ class WorkerMessageHandler {
           pdfManager.ensureCatalog("acroForm"),
           pdfManager.ensureCatalog("acroFormRef"),
           pdfManager.ensureDoc("startXRef"),
+          pdfManager.ensureDoc("linearization"),
         ];
 
         const newAnnotationsByPage = !isPureXfa
@@ -595,6 +596,7 @@ class WorkerMessageHandler {
           acroForm,
           acroFormRef,
           startXRef,
+          linearization,
           ...refs
         ]) {
           let newRefs = [];
@@ -656,7 +658,9 @@ class WorkerMessageHandler {
               infoRef: xref.trailer.getRaw("Info") || null,
               info: infoObj,
               fileIds: xref.trailer.get("ID") || null,
-              startXRef: xref.lastXRefStreamPos ?? startXRef,
+              startXRef: linearization
+                ? startXRef
+                : xref.lastXRefStreamPos ?? startXRef,
               filename,
             };
           }

src/core/writer.js

@@ -231,7 +231,7 @@ async function updateAcroform({
     warn("XFA - Cannot save it");
   }
 
-  if (!needAppearances && (!hasXfa || !xfaDatasetsRef)) {
+  if (!needAppearances && (!hasXfa || !xfaDatasetsRef || hasXfaDatasetsEntry)) {
     return;
   }
 

src/core/xref.js

@@ -33,6 +33,8 @@ import { BaseStream } from "./base_stream.js";
 import { CipherTransformFactory } from "./crypto.js";
 
 class XRef {
+  #firstXRefStmPos = null;
+
   constructor(stream, pdfManager) {
     this.stream = stream;
     this.pdfManager = pdfManager;
@@ -705,6 +707,7 @@ class XRef {
             // (possible infinite recursion)
             this._xrefStms.add(obj);
             this.startXRefQueue.push(obj);
+            this.#firstXRefStmPos ??= obj;
           }
         } else if (Number.isInteger(obj)) {
           // Parse in-stream XRef
@@ -754,7 +757,10 @@ class XRef {
   }
 
   get lastXRefStreamPos() {
-    return this._xrefStms.size > 0 ? Math.max(...this._xrefStms) : null;
+    return (
+      this.#firstXRefStmPos ??
+      (this._xrefStms.size > 0 ? Math.max(...this._xrefStms) : null)
+    );
   }
 
   getEntry(i) {