Ignore exceptions trying to read IPTC-IIM data

Author: StephenMcConnel

src/TaglibSharp.Tests/Images/BadIptcSectionTest.cs

@@ -0,0 +1,93 @@
+using NUnit.Framework;
+using TagLib;
+using TagLib.IFD;
+using TagLib.IFD.Tags;
+using TagLib.IFD.Entries;
+using TagLib.Xmp;
+using TaglibSharp.Tests.Images.Validators;
+
+namespace TaglibSharp.Tests.Images
+{
+	public class BadIptcSectionTest
+	{
+		[Test]
+		public void Test ()
+		{
+			ImageTest.Run ("sample_IPTC_crash.jpg",
+				false,
+				new BadIptcSectionTestInvariantValidator (),
+				NoModificationValidator.Instance,
+				new PropertyModificationValidator<string> ("Copyright", null, "Copyright 2024 by Somebody Im Sure")
+			);
+		}
+	}
+	public class BadIptcSectionTestInvariantValidator : IMetadataInvariantValidator
+	{
+		int calls = 0;
+		public void ValidateMetadataInvariants (TagLib.Image.File file)
+		{
+			// If we get here, the fix works.
+			++calls;
+
+			Assert.IsNotNull (file);
+
+			Assert.IsFalse (file.PossiblyCorrupt);	// The only problem is in the IPTC section, which we ignore.
+
+			var tag = file.GetTag (TagTypes.TiffIFD) as IFDTag;
+			Assert.IsNotNull (tag, "IFD tag not found");
+
+			var structure = tag.Structure;
+
+			var exif = structure.GetEntry (0, (ushort)IFDEntryTag.ExifIFD) as SubIFDEntry;
+			Assert.IsNotNull (exif, "Exif tag not found");
+
+			var exif_structure = exif.Structure;
+			{
+				var entry = exif_structure.GetEntry (0, (ushort)ExifEntryTag.ExifVersion);
+				Assert.IsNotNull (entry, "Entry 0x9000 missing in IFD 0");
+				Assert.IsNotNull (entry as UndefinedIFDEntry, "Entry is not an undefined IFD entry!");
+				var parsed_bytes = (entry as UndefinedIFDEntry).Data.Data;
+				var bytes = new byte[] { 48, 50, 51, 49 };
+				Assert.AreEqual (bytes, parsed_bytes);
+			}
+			{
+				var entry = exif_structure.GetEntry (0, (ushort)ExifEntryTag.ColorSpace);
+				Assert.IsNotNull (entry, "Entry 0xa001 missing in IFD 0");
+				Assert.IsNotNull (entry as ShortIFDEntry, "Entry is not a short IFD entry!");
+				var parsed_value = (entry as ShortIFDEntry).Value;
+				Assert.AreEqual (65535, parsed_value);
+			}
+			{
+				var entry = exif_structure.GetEntry (0, (ushort)ExifEntryTag.PixelXDimension);
+				Assert.IsNotNull (entry, "Entry 0xa001 missing in IFD 0");
+				Assert.IsNotNull (entry as LongIFDEntry, "Entry is not a long IFD entry!");
+				var parsed_value = (entry as LongIFDEntry).Value;
+				Assert.AreEqual (4845, parsed_value);
+			}
+			{
+				var entry = exif_structure.GetEntry (0, (ushort)ExifEntryTag.PixelYDimension);
+				Assert.IsNotNull (entry, "Entry 0xa001 missing in IFD 0");
+				Assert.IsNotNull (entry as LongIFDEntry, "Entry is not a long IFD entry!");
+				var parsed_value = (entry as LongIFDEntry).Value;
+				Assert.AreEqual (2834, parsed_value);
+			}
+
+
+			var xmp = file.GetTag (TagTypes.XMP) as XmpTag;
+			Assert.IsNotNull (xmp, "XMP tag not found");
+
+			Assert.AreEqual ("Adobe Photoshop 22.1 (Windows)", xmp.Software);
+			// ValidateMetadataInvariants is called 3 times for each Validator: once in the
+			// ParseUnmodifiedFile method, once in the ModifyFile method before changing
+			// anything, and once in the ParseModifiedFile method.
+			// The PropertyModificationValidator class verifies the property setting, but
+			// I'm not sure I totally trust it, so I'm going to check the property value
+			// here as well.
+			if (calls == 1)
+				Assert.IsNull (xmp.Copyright);
+			if (xmp.Copyright != null)
+				Assert.AreEqual ("Copyright 2024 by Somebody Im Sure", xmp.Copyright);
+			Assert.IsNull (xmp.Creator);
+		}
+	}
+}

src/TaglibSharp.Tests/samples/sample_IPTC_crash.jpg

@@ -561,10 +561,14 @@ void ReadAPP13Segment (ushort length)
 			}
 			data.RemoveRange (0, iptc_iim_length + lenToSkip);
 
-			var reader = new IIM.IIMReader (data);
-			var tag = reader.Process ();
-			if (tag != null)
-				ImageTag.AddTag (tag);
+			try {
+				var reader = new IIM.IIMReader (data);
+				var tag = reader.Process ();
+				if (tag != null)
+					ImageTag.AddTag (tag);
+			} catch (Exception) {
+				// There isn't much we handle in the IPTC section, so we just ignore any errors.
+			}
 		}
 
 		/// <summary>