From 64679073185be2b1983ddd8834a29f353bdb0de4 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Tue, 22 Jun 2021 15:44:52 +0200
Subject: [PATCH] Support corrupt documents with *empty* `Name`-entries (issue
 13610)

Apparently some really bad PDF software can create documents with *empty* `Name`-entries, which we thus need to somehow deal with.
While I don't know if this patch is necessarily the best solution, it should at least ensure that the *empty* `Name`-instance cannot accidentally match a proper `Name`-instance (and it doesn't require changes to a lot of existing code).[1]

---
[1] I briefly considered using a `Symbol` rather than an Object, but quickly decided against that since the former one [is not clonable](https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm#supported_types) and `Name`-instances may be sent to the API.
---
 src/core/parser.js            | 3 +++
 src/core/primitives.js        | 6 ++++++
 test/pdfs/issue13610.pdf.link | 1 +
 test/test_manifest.json       | 7 +++++++
 test/unit/evaluator_spec.js   | 2 +-
 5 files changed, 18 insertions(+), 1 deletion(-)
 create mode 100644 test/pdfs/issue13610.pdf.link

diff --git a/src/core/parser.js b/src/core/parser.js
index b3970f7bf..bc8381070 100644
--- a/src/core/parser.js
+++ b/src/core/parser.js
@@ -1113,6 +1113,9 @@ class Lexer {
     }
     if (strBuf.length > 127) {
       warn(`Name token is longer than allowed by the spec: ${strBuf.length}`);
+    } else if (strBuf.length === 0) {
+      warn("Name token is empty.");
+      return Name.empty;
     }
     return Name.get(strBuf.join(""));
   }
diff --git a/src/core/primitives.js b/src/core/primitives.js
index c35dedef5..4e96b7b85 100644
--- a/src/core/primitives.js
+++ b/src/core/primitives.js
@@ -33,6 +33,12 @@ const Name = (function NameClosure() {
       return nameValue ? nameValue : (nameCache[name] = new Name(name));
     }
 
+    static get empty() {
+      // eslint-disable-next-line no-restricted-syntax
+      const emptyName = new Name({ empty: true });
+      return shadow(this, "empty", emptyName);
+    }
+
     static _clearCache() {
       nameCache = Object.create(null);
     }
diff --git a/test/pdfs/issue13610.pdf.link b/test/pdfs/issue13610.pdf.link
new file mode 100644
index 000000000..1ca4adb7b
--- /dev/null
+++ b/test/pdfs/issue13610.pdf.link
@@ -0,0 +1 @@
+https://github.com/mozilla/pdf.js/files/6694277/Unitfactuur_18707277_KORTELAND_PRINTEN.INSCANNEN.pdf
diff --git a/test/test_manifest.json b/test/test_manifest.json
index f203d4b8a..b8e9c94b0 100644
--- a/test/test_manifest.json
+++ b/test/test_manifest.json
@@ -1612,6 +1612,13 @@
        "rounds": 1,
        "type": "eq"
     },
+    {  "id": "issue13610",
+       "file": "pdfs/issue13610.pdf",
+       "md5": "5b894c0b1b2279a245c23abd76648ca9",
+       "link": true,
+       "rounds": 1,
+       "type": "eq"
+    },
     {  "id": "simpletype3font-text",
        "file": "pdfs/simpletype3font.pdf",
        "md5": "b374c7543920840c61999e9e86939f99",
diff --git a/test/unit/evaluator_spec.js b/test/unit/evaluator_spec.js
index 4379095dd..0b651e3a8 100644
--- a/test/unit/evaluator_spec.js
+++ b/test/unit/evaluator_spec.js
@@ -325,7 +325,7 @@ describe("evaluator", function () {
         expect(false).toEqual(true);
       } catch (reason) {
         expect(reason instanceof FormatError).toEqual(true);
-        expect(reason.message).toEqual("XObject must be referred to by name.");
+        expect(reason.message).toEqual("XObject should be a stream");
       }
     });