Prevent errors when parsing Annotations with missing (or invalid) /Subtype entries (issue 7446)

Note that I used a separate warning message for this case, instead of utilizing the same one as in the unsupported subtype case, to more clearly indicate that the PDF file itself is to blame rather than PDF.js.

Fixes 7446.

src/core/annotation.js

@@ -74,13 +74,14 @@ AnnotationFactory.prototype = /** @lends AnnotationFactory.prototype */ {
 
     // Determine the annotation's subtype.
     var subtype = dict.get('Subtype');
-    subtype = isName(subtype) ? subtype.name : '';
+    subtype = isName(subtype) ? subtype.name : null;
 
     // Return the right annotation object based on the subtype and field type.
     var parameters = {
       xref: xref,
       dict: dict,
-      ref: ref
+      ref: ref,
+      subtype: subtype,
     };
 
     switch (subtype) {
@@ -116,8 +117,12 @@ AnnotationFactory.prototype = /** @lends AnnotationFactory.prototype */ {
         return new FileAttachmentAnnotation(parameters);
 
       default:
-        warn('Unimplemented annotation type "' + subtype + '", ' +
+        if (!subtype) {
-             'falling back to base annotation');
+          warn('Annotation is missing the required /Subtype.');
+        } else {
+          warn('Unimplemented annotation type "' + subtype + '", ' +
+               'falling back to base annotation.');
+        }
         return new Annotation(parameters);
     }
   }
@@ -181,7 +186,7 @@ var Annotation = (function AnnotationClosure() {
     // Expose public properties using a data object.
     this.data = {};
     this.data.id = params.ref.toString();
-    this.data.subtype = dict.get('Subtype').name;
+    this.data.subtype = params.subtype;
     this.data.annotationFlags = this.flags;
     this.data.rect = this.rectangle;
     this.data.color = this.color;

test/pdfs/.gitignore

@@ -31,6 +31,7 @@
 !issue7403.pdf
 !issue7426.pdf
 !issue7439.pdf
+!issue7446.pdf
 !issue7492.pdf
 !filled-background.pdf
 !ArabicCIDTrueType.pdf

test/pdfs/issue7446.pdf

@@ -0,0 +1,51 @@
+%PDF-1.7
+%%μῦ
+
+1 0 obj
+<</Type/Catalog/Pages 2 0 R>>
+endobj
+
+2 0 obj
+<</Type/Pages/MediaBox[0 0 200 200]/Count 1/Kids[3 0 R]>>
+endobj
+
+3 0 obj
+<</Type/Page/Parent 2 0 R/Annots[6 0 R]/Resources<</Font<</F1 4 0 R>>>>/Contents 5 0 R>>
+endobj
+
+4 0 obj
+<</Type/Font/Subtype/Type1/BaseFont/Times-Roman>>
+endobj
+
+5 0 obj
+<</Length 68>>
+stream
+BT
+10 10 TD
+/F1 12 Tf
+(Renders even with a broken annotation) Tj
+ET
+
+endstream
+endobj
+
+6 0 obj
+<</Type/Annot/Rect[266 116 430 204]/Contents( This annotation is broken )>>
+endobj
+
+xref
+0 7
+0000000000 65536 f 
+0000000018 00000 n 
+0000000064 00000 n 
+0000000138 00000 n 
+0000000243 00000 n 
+0000000309 00000 n 
+0000000426 00000 n 
+
+trailer
+<</Size 7/Root 1 0 R>>
+
+startxref
+518
+%%EOF

test/test_manifest.json

@@ -1131,6 +1131,14 @@
        "link": false,
        "type": "eq"
     },
+    {  "id": "issue7446",
+       "file": "pdfs/issue7446.pdf",
+       "md5": "1b5bdd8a806e6ab9eda7c1c707b75fc6",
+       "rounds": 1,
+       "link": false,
+       "type": "load",
+       "about": "Annotation without the required /Subtype."
+    },
     {  "id": "issue7492-eq",
        "file": "pdfs/issue7492.pdf",
        "md5": "7b0b28919c1088a2a5a0aeedbaa4c3ca",

test/unit/annotation_layer_spec.js

@@ -26,11 +26,35 @@ describe('Annotation layer', function() {
     annotationFactory = null;
   });
 
+  describe('AnnotationFactory', function () {
+    it('should handle missing /Subtype', function () {
+      var annotationDict = new Dict();
+      annotationDict.set('Type', Name.get('Annot'));
+
+      var xrefMock = new XrefMock([annotationDict]);
+      var annotationRef = new Ref(1, 0);
+
+      var annotation = annotationFactory.create(xrefMock, annotationRef);
+      var data = annotation.data;
+      expect(data.annotationType).toBeUndefined();
+    });
+  });
+
   describe('Annotation', function() {
+    var dict, ref;
+
+    beforeAll(function (done) {
+      dict = new Dict();
+      ref = new Ref(1, 0);
+      done();
+    });
+
+    afterAll(function () {
+      dict = ref = null;
+    });
+
     it('should set and get flags', function() {
-      var dict = new Dict();
+      var annotation = new Annotation({ dict: dict, ref: ref });
-      dict.set('Subtype', '');
-      var annotation = new Annotation({ dict: dict, ref: 0 });
       annotation.setFlags(13);
 
       expect(annotation.hasFlag(AnnotationFlag.INVISIBLE)).toEqual(true);
@@ -40,81 +64,63 @@ describe('Annotation layer', function() {
     });
 
     it('should be viewable and not printable by default', function() {
-      var dict = new Dict();
+      var annotation = new Annotation({ dict: dict, ref: ref });
-      dict.set('Subtype', '');
-      var annotation = new Annotation({ dict: dict, ref: 0 });
 
       expect(annotation.viewable).toEqual(true);
       expect(annotation.printable).toEqual(false);
     });
 
     it('should set and get a valid rectangle', function() {
-      var dict = new Dict();
+      var annotation = new Annotation({ dict: dict, ref: ref });
-      dict.set('Subtype', '');
-      var annotation = new Annotation({ dict: dict, ref: 0 });
       annotation.setRectangle([117, 694, 164.298, 720]);
 
       expect(annotation.rectangle).toEqual([117, 694, 164.298, 720]);
     });
 
     it('should not set and get an invalid rectangle', function() {
-      var dict = new Dict();
+      var annotation = new Annotation({ dict: dict, ref: ref });
-      dict.set('Subtype', '');
-      var annotation = new Annotation({ dict: dict, ref: 0 });
       annotation.setRectangle([117, 694, 164.298]);
 
       expect(annotation.rectangle).toEqual([0, 0, 0, 0]);
     });
 
     it('should reject a color if it is not an array', function() {
-      var dict = new Dict();
+      var annotation = new Annotation({ dict: dict, ref: ref });
-      dict.set('Subtype', '');
-      var annotation = new Annotation({ dict: dict, ref: 0 });
       annotation.setColor('red');
 
       expect(annotation.color).toEqual(new Uint8Array([0, 0, 0]));
     });
 
     it('should set and get a transparent color', function() {
-      var dict = new Dict();
+      var annotation = new Annotation({ dict: dict, ref: ref });
-      dict.set('Subtype', '');
-      var annotation = new Annotation({ dict: dict, ref: 0 });
       annotation.setColor([]);
 
       expect(annotation.color).toEqual(null);
     });
 
     it('should set and get a grayscale color', function() {
-      var dict = new Dict();
+      var annotation = new Annotation({ dict: dict, ref: ref });
-      dict.set('Subtype', '');
-      var annotation = new Annotation({ dict: dict, ref: 0 });
       annotation.setColor([0.4]);
 
       expect(annotation.color).toEqual(new Uint8Array([102, 102, 102]));
     });
 
     it('should set and get an RGB color', function() {
-      var dict = new Dict();
+      var annotation = new Annotation({ dict: dict, ref: ref });
-      dict.set('Subtype', '');
-      var annotation = new Annotation({ dict: dict, ref: 0 });
       annotation.setColor([0, 0, 1]);
 
       expect(annotation.color).toEqual(new Uint8Array([0, 0, 255]));
     });
 
     it('should set and get a CMYK color', function() {
-      var dict = new Dict();
+      var annotation = new Annotation({ dict: dict, ref: ref });
-      dict.set('Subtype', '');
-      var annotation = new Annotation({ dict: dict, ref: 0 });
       annotation.setColor([0.1, 0.92, 0.84, 0.02]);
 
       expect(annotation.color).toEqual(new Uint8Array([233, 59, 47]));
     });
 
     it('should not set and get an invalid color', function() {
-      var dict = new Dict();
+      var annotation = new Annotation({ dict: dict, ref: ref });
-      dict.set('Subtype', '');
-      var annotation = new Annotation({ dict: dict, ref: 0 });
       annotation.setColor([0.4, 0.6]);
 
       expect(annotation.color).toEqual(new Uint8Array([0, 0, 0]));