Convert the PDFDocumentProperties class to use private methods

Given that none of these methods were ever intended to be accessed directly from the outside, we can use modern ECMAScript features to ensure that they are indeed private.

This patch also makes `fieldData` private, to remove the old hack used to prevent it from being modified from the outside.

web/pdf_document_properties.js

@@ -52,6 +52,8 @@ function getPageName(size, isPortrait, pageNames) {
  */
 
 class PDFDocumentProperties {
+  #fieldData = null;
+
   /**
    * @param {PDFDocumentPropertiesOptions} options
    * @param {OverlayManager} overlayManager - Manager for the viewer overlays.
@@ -70,7 +72,7 @@ class PDFDocumentProperties {
     this.overlayManager = overlayManager;
     this.l10n = l10n;
 
-    this._reset();
+    this.#reset();
     // Bind the event listener for the Close button.
     closeButton.addEventListener("click", this.close.bind(this));
 
@@ -97,15 +99,6 @@ class PDFDocumentProperties {
    * Open the document properties overlay.
    */
   async open() {
-    const freezeFieldData = data => {
-      Object.defineProperty(this, "fieldData", {
-        value: Object.freeze(data),
-        writable: false,
-        enumerable: true,
-        configurable: true,
-      });
-    };
-
     await Promise.all([
       this.overlayManager.open(this.overlayName),
       this._dataAvailableCapability.promise,
@@ -116,11 +109,11 @@ class PDFDocumentProperties {
     // If the document properties were previously fetched (for this PDF file),
     // just update the dialog immediately to avoid redundant lookups.
     if (
-      this.fieldData &&
-      currentPageNumber === this.fieldData._currentPageNumber &&
-      pagesRotation === this.fieldData._pagesRotation
+      this.#fieldData &&
+      currentPageNumber === this.#fieldData._currentPageNumber &&
+      pagesRotation === this.#fieldData._pagesRotation
     ) {
-      this._updateUI();
+      this.#updateUI();
       return;
     }
 
@@ -141,16 +134,16 @@ class PDFDocumentProperties {
       isLinearized,
     ] = await Promise.all([
       contentDispositionFilename || getPdfFilenameFromUrl(this.url),
-      this._parseFileSize(contentLength),
-      this._parseDate(info.CreationDate),
-      this._parseDate(info.ModDate),
+      this.#parseFileSize(contentLength),
+      this.#parseDate(info.CreationDate),
+      this.#parseDate(info.ModDate),
       this.pdfDocument.getPage(currentPageNumber).then(pdfPage => {
-        return this._parsePageSize(getPageSizeInches(pdfPage), pagesRotation);
+        return this.#parsePageSize(getPageSizeInches(pdfPage), pagesRotation);
       }),
-      this._parseLinearization(info.IsLinearized),
+      this.#parseLinearization(info.IsLinearized),
     ]);
 
-    freezeFieldData({
+    this.#fieldData = Object.freeze({
       fileName,
       fileSize,
       title: info.Title,
@@ -168,7 +161,7 @@ class PDFDocumentProperties {
       _currentPageNumber: currentPageNumber,
       _pagesRotation: pagesRotation,
     });
-    this._updateUI();
+    this.#updateUI();
 
     // Get the correct fileSize, since it may not have been available
     // or could potentially be wrong.
@@ -176,11 +169,11 @@ class PDFDocumentProperties {
     if (contentLength === length) {
       return; // The fileSize has already been correctly set.
     }
-    const data = Object.assign(Object.create(null), this.fieldData);
-    data.fileSize = await this._parseFileSize(length);
+    const data = Object.assign(Object.create(null), this.#fieldData);
+    data.fileSize = await this.#parseFileSize(length);
 
-    freezeFieldData(data);
-    this._updateUI();
+    this.#fieldData = Object.freeze(data);
+    this.#updateUI();
   }
 
   /**
@@ -201,8 +194,8 @@ class PDFDocumentProperties {
    */
   setDocument(pdfDocument, url = null) {
     if (this.pdfDocument) {
-      this._reset();
-      this._updateUI(true);
+      this.#reset();
+      this.#updateUI(true);
     }
     if (!pdfDocument) {
       return;
@@ -213,14 +206,11 @@ class PDFDocumentProperties {
     this._dataAvailableCapability.resolve();
   }
 
-  /**
-   * @private
-   */
-  _reset() {
+  #reset() {
     this.pdfDocument = null;
     this.url = null;
 
-    delete this.fieldData;
+    this.#fieldData = null;
     this._dataAvailableCapability = createPromiseCapability();
     this._currentPageNumber = 1;
     this._pagesRotation = 0;
@@ -230,10 +220,9 @@ class PDFDocumentProperties {
    * Always updates all of the dialog fields, to prevent inconsistent UI state.
    * NOTE: If the contents of a particular field is neither a non-empty string,
    *       nor a number, it will fall back to `DEFAULT_FIELD_CONTENT`.
-   * @private
    */
-  _updateUI(reset = false) {
-    if (reset || !this.fieldData) {
+  #updateUI(reset = false) {
+    if (reset || !this.#fieldData) {
       for (const id in this.fields) {
         this.fields[id].textContent = DEFAULT_FIELD_CONTENT;
       }
@@ -245,16 +234,13 @@ class PDFDocumentProperties {
       return;
     }
     for (const id in this.fields) {
-      const content = this.fieldData[id];
+      const content = this.#fieldData[id];
       this.fields[id].textContent =
         content || content === 0 ? content : DEFAULT_FIELD_CONTENT;
     }
   }
 
-  /**
-   * @private
-   */
-  async _parseFileSize(fileSize = 0) {
+  async #parseFileSize(fileSize = 0) {
     const kb = fileSize / 1024,
       mb = kb / 1024;
     if (!kb) {
@@ -267,10 +253,7 @@ class PDFDocumentProperties {
     });
   }
 
-  /**
-   * @private
-   */
-  async _parsePageSize(pageSizeInches, pagesRotation) {
+  async #parsePageSize(pageSizeInches, pagesRotation) {
     if (!pageSizeInches) {
       return undefined;
     }
@@ -364,10 +347,7 @@ class PDFDocumentProperties {
     );
   }
 
-  /**
-   * @private
-   */
-  async _parseDate(inputDate) {
+  async #parseDate(inputDate) {
     const dateObject = PDFDateString.toDateObject(inputDate);
     if (!dateObject) {
       return undefined;
@@ -378,10 +358,7 @@ class PDFDocumentProperties {
     });
   }
 
-  /**
-   * @private
-   */
-  _parseLinearization(isLinearized) {
+  #parseLinearization(isLinearized) {
     return this.l10n.get(
       `document_properties_linearized_${isLinearized ? "yes" : "no"}`
     );