Fix for #662: when encountering invalid content, try to continue parsing

if option "useLenientParsing" is in effect.

src/UglyToad.PdfPig.Tests/Integration/InvalidOperator.cs

@@ -0,0 +1,33 @@
+namespace UglyToad.PdfPig.Tests.Integration
+{
+    using System;
+    using Xunit;
+
+    public class InvalidOperatorTests
+    {
+        [Fact]
+        public void InvalidOperatorThrowsExceptionIfNotUsingLenientParsing()
+        {
+            var path = IntegrationHelpers.GetSpecificTestDocumentPath("invalid-operator.pdf");
+
+            using (var document = PdfDocument.Open(path, new ParsingOptions { UseLenientParsing = false }))
+            {
+                Assert.Throws<ArgumentException>(() => document.GetPage(1));
+            }
+        }
+
+        [Fact]
+        public void InvalidOperatorDoesNotThrowExceptionIfUsingLenientParsing()
+        {
+            var path = IntegrationHelpers.GetSpecificTestDocumentPath("invalid-operator.pdf");
+
+            using (var document = PdfDocument.Open(path, new ParsingOptions { UseLenientParsing = true }))
+            {
+                var page = document.GetPage(1);
+                var text = page.Text;
+                Assert.True(text.Contains("Text line 1"));
+                Assert.True(text.Contains("Text line 2"));
+            }
+        }
+    }
+}

src/UglyToad.PdfPig/Parser/PageContentParser.cs

@@ -15,10 +15,12 @@
     internal class PageContentParser : IPageContentParser
     {
         private readonly IGraphicsStateOperationFactory operationFactory;
+        private readonly bool useLenientParsing;
 
-        public PageContentParser(IGraphicsStateOperationFactory operationFactory)
+        public PageContentParser(IGraphicsStateOperationFactory operationFactory, bool useLenientParsing = false)
         {
             this.operationFactory = operationFactory;
+            this.useLenientParsing = useLenientParsing;
         }
 
         public IReadOnlyList<IGraphicsStateOperation> Parse(
@@ -116,9 +118,10 @@
                         catch (Exception ex)
                         {
                             // End images can cause weird state if the "EI" appears inside the inline data stream.
-                            if (TryGetLastEndImage(graphicsStateOperations, out _, out _))
+                            log.Error($"Failed reading operation at offset {inputBytes.CurrentOffset} for page {pageNumber}, data: '{op.Data}'", ex);
+                            if (TryGetLastEndImage(graphicsStateOperations, out _, out _)
+                                || useLenientParsing)
                             {
-                                log.Error($"Failed reading an operation at offset {inputBytes.CurrentOffset} for page {pageNumber}.", ex);
                                 operation = null;
                             }
                             else

src/UglyToad.PdfPig/Parser/PdfDocumentFactory.cs

@@ -195,7 +195,7 @@
                 parsingOptions.UseLenientParsing);
 
             var pageFactory = new PageFactory(pdfScanner, resourceContainer, filterProvider,
-                new PageContentParser(new ReflectionGraphicsStateOperationFactory()), parsingOptions.Logger);
+                new PageContentParser(new ReflectionGraphicsStateOperationFactory(), parsingOptions.UseLenientParsing), parsingOptions.Logger);
 
             var catalog = CatalogFactory.Create(
                 rootReference,