From 2b2234fd5a789c059c334fda44573a52ee6fbb23 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Tue, 13 Apr 2021 12:30:20 +0200
Subject: [PATCH] [api-minor] Ensure that `PDFDocumentProxy.hasJSActions` won't
 fail if `MissingDataException`s are thrown during the associated
 worker-thread parsing

With the current implementation of `PDFDocument.hasJSActions`, in the worker-thread, we're not actually handling not-yet-loaded data correctly. This can thus fail in *two* different ways:
 - The `PDFDocument.fieldObjects` getter (and its helper method), while it may *return* a Promise, still fetches all of its data synchronously and it can thus throw a `MissingDataException` during parsing.
 - The `Catalog.jsActions` getter, which is completely synchronous, can obviously throw a `MissingDataException` during parsing.

If either of these cases occur currently, the `PDFDocumentProxy.hasJSActions` method in the API can either return a *rejected* Promise (which it never should) or possibly "hang" and never resolve.

*Please note:* While I've not *yet* seen this error in an actual PDF document, it can happen during loading if you're unlucky enough with e.g. the structure of the PDF document and/or the download speed offered by the server.
This patch is thus based on code-inspection *and* on manually throwing a `MissingDataException` on the first access of `Catalog.jsActions` to simulate this situation.

Finally, this patch adds a couple of *API* unit-tests for this (since none existed).
---
 src/core/document.js  | 35 ++++++++++++++++++++++-------------
 test/unit/api_spec.js | 17 +++++++++++++++++
 2 files changed, 39 insertions(+), 13 deletions(-)

diff --git a/src/core/document.js b/src/core/document.js
index b67834c96..1e32007c1 100644
--- a/src/core/document.js
+++ b/src/core/document.js
@@ -1182,19 +1182,28 @@ class PDFDocument {
   }
 
   get hasJSActions() {
-    return shadow(
-      this,
-      "hasJSActions",
-      this.fieldObjects.then(fieldObjects => {
-        return (
-          (fieldObjects !== null &&
-            Object.values(fieldObjects).some(fieldObject =>
-              fieldObject.some(object => object.actions !== null)
-            )) ||
-          !!this.catalog.jsActions
-        );
-      })
-    );
+    const promise = this.pdfManager.ensure(this, "_parseHasJSActions");
+    return shadow(this, "hasJSActions", promise);
+  }
+
+  /**
+   * @private
+   */
+  async _parseHasJSActions() {
+    const [catalogJsActions, fieldObjects] = await Promise.all([
+      this.pdfManager.ensureCatalog("jsActions"),
+      this.pdfManager.ensure(this, "fieldObjects"),
+    ]);
+
+    if (catalogJsActions) {
+      return true;
+    }
+    if (fieldObjects) {
+      return Object.values(fieldObjects).some(fieldObject =>
+        fieldObject.some(object => object.actions !== null)
+      );
+    }
+    return false;
   }
 
   get calculationOrderIds() {
diff --git a/test/unit/api_spec.js b/test/unit/api_spec.js
index af9a494bf..40958ff9e 100644
--- a/test/unit/api_spec.js
+++ b/test/unit/api_spec.js
@@ -1014,6 +1014,23 @@ describe("api", function () {
         .catch(done.fail);
     });
 
+    it("gets hasJSActions, in document without javaScript", async function () {
+      const hasJSActions = await pdfDocument.hasJSActions();
+
+      expect(hasJSActions).toEqual(false);
+    });
+    it("gets hasJSActions, in document with javaScript", async function () {
+      const loadingTask = getDocument(
+        buildGetDocumentParams("doc_actions.pdf")
+      );
+      const pdfDoc = await loadingTask.promise;
+      const hasJSActions = await pdfDoc.hasJSActions();
+
+      expect(hasJSActions).toEqual(true);
+
+      await loadingTask.destroy();
+    });
+
     it("gets JSActions (none)", function (done) {
       const promise = pdfDocument.getJSActions();
       promise