Add better support for /Launch actions with /FileSpec dictionaries (issue 17846)

src/core/catalog.js

@@ -1568,9 +1568,13 @@ class Catalog {
         case "GoToR":
           const urlDict = action.get("F");
           if (urlDict instanceof Dict) {
-            // We assume that we found a FileSpec dictionary
-            // and fetch the URL without checking any further.
-            url = urlDict.get("F") || null;
+            const fs = new FileSpec(
+              urlDict,
+              /* xref = */ null,
+              /* skipContent = */ true
+            );
+            const { filename } = fs.serializable;
+            url = filename;
           } else if (typeof urlDict === "string") {
             url = urlDict;
           }

src/core/file_spec.js

@@ -42,7 +42,9 @@ function pickPlatformItem(dict) {
  * collections attributes and related files (/RF)
  */
 class FileSpec {
-  constructor(root, xref) {
+  #contentAvailable = false;
+
+  constructor(root, xref, skipContent = false) {
     if (!(root instanceof Dict)) {
       return;
     }
@@ -57,10 +59,12 @@ class FileSpec {
     if (root.has("RF")) {
       warn("Related file specifications are not supported");
     }
-    this.contentAvailable = true;
-    if (!root.has("EF")) {
-      this.contentAvailable = false;
-      warn("Non-embedded file specifications are not supported");
+    if (!skipContent) {
+      if (root.has("EF")) {
+        this.#contentAvailable = true;
+      } else {
+        warn("Non-embedded file specifications are not supported");
+      }
     }
   }
 
@@ -76,7 +80,7 @@ class FileSpec {
   }
 
   get content() {
-    if (!this.contentAvailable) {
+    if (!this.#contentAvailable) {
       return null;
     }
     if (!this.contentRef && this.root) {