Add support for the /Catalog Base-URI when resolving URLs (issue 14802)

As far as I can tell, this is actually the very first time that we've seen a PDF document with a Base-URI specified in the /Catalog; please refer to the specification:
https://web.archive.org/web/20220309040754if_/https://www.adobe.com/content/dam/acom/en/devnet/pdf/pdfs/PDF32000_2008.pdf#G11.2097122

To simplify the overall implementation, this new parameter is accessed via the existing `BasePdfManager.docBaseUrl`-getter and will thus override any user-specified `docBaseUrl` API-parameter.

src/core/annotation.js

@@ -72,9 +72,12 @@ class AnnotationFactory {
   static create(xref, ref, pdfManager, idFactory, collectFields) {
     return Promise.all([
       pdfManager.ensureCatalog("acroForm"),
+      // Only necessary to prevent the `pdfManager.docBaseUrl`-getter, used
+      // with certain Annotations, from throwing and thus breaking parsing:
+      pdfManager.ensureCatalog("baseUrl"),
       pdfManager.ensureDoc("xfaDatasets"),
       collectFields ? this._getPageIndex(xref, ref, pdfManager) : -1,
-    ]).then(([acroForm, xfaDatasets, pageIndex]) =>
+    ]).then(([acroForm, baseUrl, xfaDatasets, pageIndex]) =>
       pdfManager.ensure(this, "_create", [
         xref,
         ref,

src/core/catalog.js

@@ -1387,6 +1387,22 @@ class Catalog {
     return next(pageRef);
   }
 
+  get baseUrl() {
+    const uri = this._catDict.get("URI");
+    if (uri instanceof Dict) {
+      const base = uri.get("Base");
+      if (typeof base === "string") {
+        const absoluteUrl = createValidAbsoluteUrl(base, null, {
+          tryConvertEncoding: true,
+        });
+        if (absoluteUrl) {
+          return shadow(this, "baseUrl", absoluteUrl.href);
+        }
+      }
+    }
+    return shadow(this, "baseUrl", null);
+  }
+
   /**
    * @typedef {Object} ParseDestDictionaryParameters
    * @property {Dict} destDict - The dictionary containing the destination.
@@ -1464,8 +1480,6 @@ class Catalog {
             // Some bad PDFs do not put parentheses around relative URLs.
             url = "/" + url.name;
           }
-          // TODO: pdf spec mentions urls can be relative to a Base
-          // entry in the dictionary.
           break;
 
         case "GoTo":

src/core/pdf_manager.js

@@ -13,7 +13,12 @@
  * limitations under the License.
  */
 
-import { createValidAbsoluteUrl, unreachable, warn } from "../shared/util.js";
+import {
+  createValidAbsoluteUrl,
+  shadow,
+  unreachable,
+  warn,
+} from "../shared/util.js";
 import { ChunkedStreamManager } from "./chunked_stream.js";
 import { MissingDataException } from "./core_utils.js";
 import { PDFDocument } from "./document.js";
@@ -46,7 +51,8 @@ class BasePdfManager {
   }
 
   get docBaseUrl() {
-    return this._docBaseUrl;
+    const catalog = this.pdfDocument.catalog;
+    return shadow(this, "docBaseUrl", catalog.baseUrl || this._docBaseUrl);
   }
 
   onLoadedStream() {

test/pdfs/.gitignore

@@ -238,6 +238,7 @@
 !pdfjsbad1586.pdf
 !standard_fonts.pdf
 !freeculture.pdf
+!issue14802.pdf
 !issue6006.pdf
 !pdfkit_compressed.pdf
 !TAMReview.pdf

test/pdfs/issue14802.pdf

@@ -0,0 +1,89 @@
+%PDF-1.7
+%âãÏÓ
+1 0 obj 
+<<
+/Pages 2 0 R
+/URI 
+<<
+/Base (http://example.com/)
+>>
+/Type /Catalog
+>>
+endobj 
+2 0 obj 
+<<
+/Kids [3 0 R]
+/Type /Pages
+/Count 1
+>>
+endobj 
+3 0 obj 
+<<
+/Parent 2 0 R
+/Annots [4 0 R]
+/Resources 
+<<
+/Font 
+<<
+/F1 5 0 R
+>>
+>>
+/MediaBox [0 0 260 50]
+/Type /Page
+/Contents 6 0 R
+>>
+endobj 
+4 0 obj 
+<<
+/Border [0 0 1]
+/Subtype /Link
+/C [0 0 1]
+/A 
+<<
+/URI (./relative_link.txt)
+/Type /Action
+/S /URI
+>>
+/Type /Annot
+/Rect [5 10 250 40]
+>>
+endobj 
+5 0 obj 
+<<
+/BaseFont /Times-Roman
+/Subtype /Type1
+/Type /Font
+/Encoding /WinAnsiEncoding
+>>
+endobj 
+6 0 obj 
+<<
+/Length 81
+>>
+stream
+1 0 0 rg
+BT
+10 20 TD
+/F1 14 Tf
+(A relative link, with a /Catalog Base-URI) Tj
+ET
+
+endstream 
+endobj xref
+0 7
+0000000000 65535 f 
+0000000015 00000 n 
+0000000106 00000 n 
+0000000165 00000 n 
+0000000310 00000 n 
+0000000467 00000 n 
+0000000568 00000 n 
+trailer
+
+<<
+/Root 1 0 R
+/Size 7
+>>
+startxref
+701
+%%EOF

test/test_manifest.json

@@ -2950,6 +2950,14 @@
       "link": true,
       "type": "eq"
     },
+    {  "id": "issue14802",
+       "file": "pdfs/issue14802.pdf",
+       "md5": "c1e774945fee539c7fcfec00b36dd4e6",
+       "rounds": 1,
+       "type": "eq",
+       "annotations": true,
+       "about": "LinkAnnotation with a relative link, and a /Catalog Base-URI."
+    },
     {  "id": "issue1127-text",
        "file": "pdfs/issue1127.pdf",
        "md5": "4fb2be5ffefeafda4ba977de2a1bb4d8",