XFA - Add a storage to save fields values - this is required to be able to print (or save) a document. Some pages can be unloaded (because pdf.js is lazy) and this storage will help to save their data in order to resuse them when printing or just when displaying a page again.

src/core/xfa/template.js

@@ -941,11 +941,14 @@ class CheckButton extends XFAObject {
       style.height = size;
     }
 
+    const fieldId = this[$getParent]()[$getParent]()[$uid];
     const input = {
       name: "input",
       attributes: {
         class: "xfaCheckbox",
+        fieldId,
         type: "radio",
+        id: `${fieldId}-radio`,
       },
     };
 
@@ -1023,6 +1026,7 @@ class ChoiceList extends XFAObject {
 
     const selectAttributes = {
       class: "xfaSelect",
+      fieldId: this[$getParent]()[$getParent]()[$uid],
       style,
     };
 
@@ -1249,6 +1253,7 @@ class DateTimeEdit extends XFAObject {
       name: "input",
       attributes: {
         type: "text",
+        fieldId: this[$getParent]()[$getParent]()[$uid],
         class: "xfaTextfield",
         style,
       },
@@ -3012,6 +3017,7 @@ class NumericEdit extends XFAObject {
       name: "input",
       attributes: {
         type: "text",
+        fieldId: this[$getParent]()[$getParent]()[$uid],
         class: "xfaTextfield",
         style,
       },
@@ -4550,6 +4556,7 @@ class TextEdit extends XFAObject {
       html = {
         name: "textarea",
         attributes: {
+          fieldId: this[$getParent]()[$getParent]()[$uid],
           class: "xfaTextfield",
           style,
         },
@@ -4559,6 +4566,7 @@ class TextEdit extends XFAObject {
         name: "input",
         attributes: {
           type: "text",
+          fieldId: this[$getParent]()[$getParent]()[$uid],
           class: "xfaTextfield",
           style,
         },

src/display/xfa_layer.js

@@ -14,9 +14,60 @@
  */
 
 class XfaLayer {
-  static setAttributes(html, attrs) {
-    for (const [key, value] of Object.entries(attrs)) {
-      if (value === null || value === undefined) {
+  static setupStorage(html, fieldId, element, storage) {
+    const storedData = storage.getValue(fieldId, { value: null });
+    switch (element.name) {
+      case "textarea":
+        html.textContent = storedData.value !== null ? storedData.value : "";
+        html.addEventListener("input", event => {
+          storage.setValue(fieldId, { value: event.target.value });
+        });
+        break;
+      case "input":
+        if (storedData.value !== null) {
+          html.setAttribute("value", storedData.value);
+        }
+        if (element.attributes.type === "radio") {
+          html.addEventListener("change", event => {
+            const { target } = event;
+            for (const radio of document.getElementsByName(target.name)) {
+              if (radio !== target) {
+                const id = radio.id;
+                storage.setValue(id.split("-")[0], { value: false });
+              }
+            }
+            storage.setValue(fieldId, { value: target.checked });
+          });
+        } else {
+          html.addEventListener("input", event => {
+            storage.setValue(fieldId, { value: event.target.value });
+          });
+        }
+        break;
+      case "select":
+        if (storedData.value !== null) {
+          for (const option of element.children) {
+            if (option.attributes.value === storedData.value) {
+              option.attributes.selected = true;
+            }
+          }
+        }
+        html.addEventListener("input", event => {
+          const options = event.target.options;
+          const value =
+            options.selectedIndex === -1
+              ? null
+              : options[options.selectedIndex].value;
+          storage.setValue(fieldId, { value });
+        });
+        break;
+    }
+  }
+
+  static setAttributes(html, element, storage) {
+    const { attributes } = element;
+    for (const [key, value] of Object.entries(attributes)) {
+      if (value === null || value === undefined || key === "fieldId") {
         continue;
       }
 
@@ -30,13 +81,20 @@ class XfaLayer {
         Object.assign(html.style, value);
       }
     }
+
+    // Set the value after the others to be sure overwrite
+    // any other values.
+    if (storage && attributes.fieldId !== undefined) {
+      this.setupStorage(html, attributes.fieldId, element, storage);
+    }
   }
 
   static render(parameters) {
+    const storage = parameters.annotationStorage;
     const root = parameters.xfa;
     const rootHtml = document.createElement(root.name);
     if (root.attributes) {
-      XfaLayer.setAttributes(rootHtml, root.attributes);
+      this.setAttributes(rootHtml, root);
     }
     const stack = [[root, -1, rootHtml]];
 
@@ -69,7 +127,7 @@ class XfaLayer {
       const childHtml = document.createElement(name);
       html.appendChild(childHtml);
       if (child.attributes) {
-        XfaLayer.setAttributes(childHtml, child.attributes);
+        this.setAttributes(childHtml, child, storage);
       }
 
       if (child.children && child.children.length > 0) {

web/base_viewer.js

@@ -1317,12 +1317,16 @@ class BaseViewer {
   /**
    * @param {HTMLDivElement} pageDiv
    * @param {PDFPage} pdfPage
+   * @param {AnnotationStorage} [annotationStorage] - Storage for annotation
+   *   data in forms.
    * @returns {XfaLayerBuilder}
    */
-  createXfaLayerBuilder(pageDiv, pdfPage) {
+  createXfaLayerBuilder(pageDiv, pdfPage, annotationStorage = null) {
     return new XfaLayerBuilder({
       pageDiv,
       pdfPage,
+      annotationStorage:
+        annotationStorage || this.pdfDocument?.annotationStorage,
     });
   }
 

web/pdf_page_view.js

@@ -603,7 +603,8 @@ class PDFPageView {
       if (!this.xfaLayer) {
         this.xfaLayer = this.xfaLayerFactory.createXfaLayerBuilder(
           div,
-          pdfPage
+          pdfPage,
+          /* annotationStorage = */ null
         );
       }
       this._renderXfaLayer();

web/xfa_layer_builder.js

@@ -19,15 +19,17 @@ import { XfaLayer } from "pdfjs-lib";
  * @typedef {Object} XfaLayerBuilderOptions
  * @property {HTMLDivElement} pageDiv
  * @property {PDFPage} pdfPage
+ * @property {AnnotationStorage} [annotationStorage]
  */
 
 class XfaLayerBuilder {
   /**
    * @param {XfaLayerBuilderOptions} options
    */
-  constructor({ pageDiv, pdfPage }) {
+  constructor({ pageDiv, pdfPage, annotationStorage }) {
     this.pageDiv = pageDiv;
     this.pdfPage = pdfPage;
+    this.annotationStorage = annotationStorage;
 
     this.div = null;
     this._cancelled = false;
@@ -40,29 +42,34 @@ class XfaLayerBuilder {
    *   annotations is complete.
    */
   render(viewport, intent = "display") {
-    return this.pdfPage.getXfa().then(xfa => {
-      if (this._cancelled) {
-        return;
-      }
+    return this.pdfPage
+      .getXfa()
+      .then(xfa => {
+        if (this._cancelled) {
+          return;
+        }
+        const parameters = {
+          viewport: viewport.clone({ dontFlip: true }),
+          div: this.div,
+          xfa,
+          page: this.pdfPage,
+          annotationStorage: this.annotationStorage,
+        };
 
-      const parameters = {
-        viewport: viewport.clone({ dontFlip: true }),
-        div: this.div,
-        xfa,
-        page: this.pdfPage,
-      };
+        if (this.div) {
+          XfaLayer.update(parameters);
+        } else {
+          // Create an xfa layer div and render the form
+          this.div = document.createElement("div");
+          this.pageDiv.appendChild(this.div);
+          parameters.div = this.div;
 
-      if (this.div) {
-        XfaLayer.update(parameters);
-      } else {
-        // Create an xfa layer div and render the form
-        this.div = document.createElement("div");
-        this.pageDiv.appendChild(this.div);
-        parameters.div = this.div;
-
-        XfaLayer.render(parameters);
-      }
-    });
+          XfaLayer.render(parameters);
+        }
+      })
+      .catch(error => {
+        console.error(error);
+      });
   }
 
   cancel() {
@@ -84,11 +91,13 @@ class DefaultXfaLayerFactory {
   /**
    * @param {HTMLDivElement} pageDiv
    * @param {PDFPage} pdfPage
+   * @param {AnnotationStorage} [annotationStorage]
    */
-  createXfaLayerBuilder(pageDiv, pdfPage) {
+  createXfaLayerBuilder(pageDiv, pdfPage, annotationStorage = null) {
     return new XfaLayerBuilder({
       pageDiv,
       pdfPage,
+      annotationStorage,
     });
   }
 }