Provide line number in error handler

src/FlatFile.Core/Base/FlatFileEngine.cs

@@ -18,7 +18,7 @@ public abstract class FlatFileEngine<TFieldSettings, TLayoutDescriptor> : IFlatF
         /// <summary>
         /// The handle entry read error func
         /// </summary>
-        private readonly Func<string, Exception, bool> _handleEntryReadError;
+        private readonly Func<FlatFileErrorContext, bool> _handleEntryReadError;
 
         /// <summary>
         /// Gets the line builder.
@@ -42,7 +42,7 @@ public abstract class FlatFileEngine<TFieldSettings, TLayoutDescriptor> : IFlatF
         /// Initializes a new instance of the <see cref="FlatFileEngine{TFieldSettings, TLayoutDescriptor}"/> class.
         /// </summary>
         /// <param name="handleEntryReadError">The handle entry read error.</param>
-        protected FlatFileEngine(Func<string, Exception, bool> handleEntryReadError = null)
+        protected FlatFileEngine(Func<FlatFileErrorContext, bool> handleEntryReadError = null)
         {
             _handleEntryReadError = handleEntryReadError;
         }
@@ -85,7 +85,7 @@ protected FlatFileEngine(Func<string, Exception, bool> handleEntryReadError = nu
                         throw;
                     }
 
-                    if (!_handleEntryReadError(line, ex))
+                    if (!_handleEntryReadError(new FlatFileErrorContext(line, lineNumber, ex)))
                     {
                         throw;
                     }

src/FlatFile.Core/Base/FlatFileErrorContext.cs

@@ -0,0 +1,51 @@
+namespace FlatFile.Core.Base
+{
+    using System;
+
+    /// <summary>
+    /// Provides information about a file parsing error.
+    /// </summary>
+    public struct FlatFileErrorContext
+    {
+        private readonly string line;
+        private readonly int lineNumber;
+        private readonly Exception exception;
+
+        /// <summary>
+        /// Initializes a new instance of <see cref="FlatFileErrorContext"/>.
+        /// </summary>
+        /// <param name="line">The content of the line on which the error occurred.</param>
+        /// <param name="lineNumber">The line numer at which the error occurred.</param>
+        /// <param name="exception">The error that occurred.</param>
+        public FlatFileErrorContext(string line, int lineNumber, Exception exception)
+        {
+            this.line = line;
+            this.lineNumber = lineNumber;
+            this.exception = exception;
+        }
+
+        /// <summary>
+        /// The content of the line on which the error occurred.
+        /// </summary>
+        public string Line
+        {
+            get { return line; }
+        }
+
+        /// <summary>
+        /// The line numer at which the error occurred.
+        /// </summary>
+        public int LineNumber
+        {
+            get { return lineNumber; }
+        }
+
+        /// <summary>
+        /// The error that occurred.
+        /// </summary>
+        public Exception Exception
+        {
+            get { return exception; }
+        }
+    }
+}

src/FlatFile.Core/FlatFile.Core.csproj

@@ -98,6 +98,7 @@
     <Compile Include="Base\FieldsContainer.cs" />
     <Compile Include="Base\FieldSettingsBase.cs" />
     <Compile Include="Base\FlatFileEngine.cs" />
+    <Compile Include="Base\FlatFileErrorContext.cs" />
     <Compile Include="Base\LayoutBase.cs" />
     <Compile Include="Base\LayoutDescriptorBase.cs" />
     <Compile Include="Base\LineBulderBase.cs" />

src/FlatFile.Delimited/Implementation/DelimetedFileMultiEngine.cs

@@ -18,7 +18,7 @@ public class DelimitedFileMultiEngine : FlatFileEngine<IDelimitedFieldSettingsCo
         /// <summary>
         /// The handle entry read error func
         /// </summary>
-        readonly Func<string, Exception, bool> handleEntryReadError;
+        readonly Func<FlatFileErrorContext, bool> handleEntryReadError;
         /// <summary>
         /// The layout descriptors for this engine
         /// </summary>
@@ -58,7 +58,7 @@ internal DelimitedFileMultiEngine(
             Func<string, Type> typeSelectorFunc,
             IDelimitedLineBuilderFactory lineBuilderFactory,
             IDelimitedLineParserFactory lineParserFactory,
-            Func<string, Exception, bool> handleEntryReadError = null)
+            Func<FlatFileErrorContext, bool> handleEntryReadError = null)
         {
             if (typeSelectorFunc == null) throw new ArgumentNullException("typeSelectorFunc");
             this.layoutDescriptors = layoutDescriptors.ToList();
@@ -170,7 +170,7 @@ public void Read(Stream stream)
                         throw;
                     }
 
-                    if (!handleEntryReadError(line, ex))
+                    if (!handleEntryReadError(new FlatFileErrorContext(line, lineNumber, ex)))
                     {
                         throw;
                     }

src/FlatFile.Delimited/Implementation/DelimitedFileEngine.cs

@@ -38,7 +38,7 @@ internal DelimitedFileEngine(
             IDelimitedLayoutDescriptor layoutDescriptor,
             IDelimitedLineBuilderFactory builderFactory,
             IDelimitedLineParserFactory parserFactory, 
-            Func<string, Exception, bool> handleEntryReadError = null)
+            Func<FlatFileErrorContext, bool> handleEntryReadError = null)
             : base(handleEntryReadError)
         {
             _builderFactory = builderFactory;

src/FlatFile.Delimited/Implementation/DelimitedFileEngineFactory.cs

@@ -51,10 +51,25 @@ public IFlatFileEngine GetEngine(
                 descriptor,
                 new DelimitedLineBuilderFactory(),
                 new DelimitedLineParserFactory(),
-                handleEntryReadError);
+                ctx => handleEntryReadError(ctx.Line, ctx.Exception));
         }
 
-
+        /// <summary>
+        /// Gets the <see cref="IFlatFileEngine" />.
+        /// </summary>
+        /// <param name="descriptor">The descriptor.</param>
+        /// <param name="handleEntryReadError">The handle entry read error func.</param>
+        /// <returns>IFlatFileEngine.</returns>
+        public IFlatFileEngine GetEngine(
+            IDelimitedLayoutDescriptor descriptor,
+            Func<FlatFileErrorContext, bool> handleEntryReadError)
+        {
+            return new DelimitedFileEngine(
+                descriptor,
+                new DelimitedLineBuilderFactory(),
+                new DelimitedLineParserFactory(),
+                handleEntryReadError);
+        }
 
         /// <summary>
         /// Gets the <see cref="IFlatFileMultiEngine"/>.
@@ -67,6 +82,26 @@ public IFlatFileMultiEngine GetEngine(
             IEnumerable<IDelimitedLayoutDescriptor> layoutDescriptors,
             Func<string, Type> typeSelectorFunc,
             Func<string, Exception, bool> handleEntryReadError = null)
+        {
+            return new DelimitedFileMultiEngine(
+                layoutDescriptors,
+                typeSelectorFunc,
+                new DelimitedLineBuilderFactory(),
+                lineParserFactory,
+                ctx => handleEntryReadError(ctx.Line, ctx.Exception));
+        }
+
+        /// <summary>
+        /// Gets the <see cref="IFlatFileMultiEngine"/>.
+        /// </summary>
+        /// <param name="layoutDescriptors">The layout descriptors.</param>
+        /// <param name="typeSelectorFunc">The type selector function.</param>
+        /// <param name="handleEntryReadError">The handle entry read error func.</param>
+        /// <returns>IFlatFileMultiEngine.</returns>
+        public IFlatFileMultiEngine GetEngine(
+            IEnumerable<IDelimitedLayoutDescriptor> layoutDescriptors,
+            Func<string, Type> typeSelectorFunc,
+            Func<FlatFileErrorContext, bool> handleEntryReadError)
         {
             return new DelimitedFileMultiEngine(
                 layoutDescriptors,

src/FlatFile.FixedLength/Implementation/FixedLengthFileEngine.cs

@@ -33,7 +33,7 @@ internal FixedLengthFileEngine(
             ILayoutDescriptor<IFixedFieldSettingsContainer> layoutDescriptor,
             IFixedLengthLineBuilderFactory lineBuilderFactory,
             IFixedLengthLineParserFactory lineParserFactory,
-            Func<string, Exception, bool> handleEntryReadError = null) : base(handleEntryReadError)
+            Func<FlatFileErrorContext, bool> handleEntryReadError = null) : base(handleEntryReadError)
         {
             this.lineBuilderFactory = lineBuilderFactory;
             this.lineParserFactory = lineParserFactory;

src/FlatFile.FixedLength/Implementation/FixedLengthFileEngineFactory.cs

@@ -48,7 +48,24 @@ public IFlatFileEngine GetEngine(
             return new FixedLengthFileEngine(
                 descriptor, 
                 new FixedLengthLineBuilderFactory(),
-                lineParserFactory, 
+                lineParserFactory,
+                ctx => handleEntryReadError(ctx.Line, ctx.Exception));
+        }
+
+        /// <summary>
+        /// Gets the <see cref="IFlatFileEngine" />.
+        /// </summary>
+        /// <param name="descriptor">The descriptor.</param>
+        /// <param name="handleEntryReadError">The handle entry read error func.</param>
+        /// <returns>IFlatFileEngine.</returns>
+        public IFlatFileEngine GetEngine(
+            ILayoutDescriptor<IFixedFieldSettingsContainer> descriptor,
+            Func<FlatFileErrorContext, bool> handleEntryReadError)
+        {
+            return new FixedLengthFileEngine(
+                descriptor,
+                new FixedLengthLineBuilderFactory(),
+                lineParserFactory,
                 handleEntryReadError);
         }
 
@@ -63,6 +80,26 @@ public IFlatFileMultiEngine GetEngine(
             IEnumerable<ILayoutDescriptor<IFixedFieldSettingsContainer>> layoutDescriptors,
             Func<string, int, Type> typeSelectorFunc,
             Func<string, Exception, bool> handleEntryReadError = null)
+        {
+            return new FixedLengthFileMultiEngine(
+                layoutDescriptors,
+                typeSelectorFunc,
+                new FixedLengthLineBuilderFactory(),
+                lineParserFactory,
+                ctx => handleEntryReadError(ctx.Line, ctx.Exception));
+        }
+
+        /// <summary>
+        /// Gets the <see cref="IFlatFileMultiEngine"/>.
+        /// </summary>
+        /// <param name="layoutDescriptors">The layout descriptors.</param>
+        /// <param name="typeSelectorFunc">The type selector function.</param>
+        /// <param name="handleEntryReadError">The handle entry read error func.</param>
+        /// <returns>IFlatFileMultiEngine.</returns>
+        public IFlatFileMultiEngine GetEngine(
+            IEnumerable<ILayoutDescriptor<IFixedFieldSettingsContainer>> layoutDescriptors,
+            Func<string, int, Type> typeSelectorFunc,
+            Func<FlatFileErrorContext, bool> handleEntryReadError)
         {
             return new FixedLengthFileMultiEngine(
                 layoutDescriptors,

src/FlatFile.FixedLength/Implementation/FixedLengthFileMultiEngine.cs

@@ -18,7 +18,7 @@ public class FixedLengthFileMultiEngine : FlatFileEngine<IFixedFieldSettingsCont
         /// <summary>
         /// The handle entry read error func
         /// </summary>
-        readonly Func<string, Exception, bool> handleEntryReadError;
+        readonly Func<FlatFileErrorContext, bool> handleEntryReadError;
         /// <summary>
         /// The layout descriptors for this engine
         /// </summary>
@@ -58,7 +58,7 @@ internal FixedLengthFileMultiEngine(
             Func<string, int, Type> typeSelectorFunc,
             IFixedLengthLineBuilderFactory lineBuilderFactory,
             IFixedLengthLineParserFactory lineParserFactory,
-            Func<string, Exception, bool> handleEntryReadError = null)
+            Func<FlatFileErrorContext, bool> handleEntryReadError = null)
         {
             if (typeSelectorFunc == null) throw new ArgumentNullException("typeSelectorFunc");
             this.layoutDescriptors = layoutDescriptors.ToList();
@@ -191,7 +191,7 @@ private void ReadInternal(StreamReader reader)
                         throw;
                     }
 
-                    if (!handleEntryReadError(line, ex))
+                    if (!handleEntryReadError(new FlatFileErrorContext(line, lineNumber, ex)))
                     {
                         throw;
                     }

src/FlatFile.Tests/Delimited/DelimitedErrorHandlingTests.cs

@@ -0,0 +1,93 @@
+using FakeItEasy;
+using FlatFile.Core.Base;
+using FlatFile.Delimited;
+using FlatFile.Delimited.Implementation;
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using Xunit;
+
+namespace FlatFile.Tests.Delimited
+{
+    public class DelimitedErrorHandlingTests
+    {
+        private IDelimitedLayoutDescriptor layout;
+        readonly IDelimitedLineParserFactory lineParserFactory;
+        readonly IList<FlatFileErrorContext> errorContexts = new List<FlatFileErrorContext>();
+
+        const string TestData = 
+@"S,Test Description,00042
+S,Test Description,00043
+S,Test Description,00044";
+
+        public DelimitedErrorHandlingTests()
+        {
+            layout = A.Fake<IDelimitedLayoutDescriptor>();
+            A.CallTo(() => layout.TargetType).Returns(typeof(Record));
+
+            lineParserFactory = A.Fake<IDelimitedLineParserFactory>();
+            A.CallTo(() => lineParserFactory.GetParser(A<IDelimitedLayoutDescriptor>.Ignored))
+                .Returns(new FakeLineParser());
+
+            new DelimitedLineParserFactory(new Dictionary<Type, Type>
+            {
+                { typeof(Record), typeof(FakeLineParser) }
+            });
+        }
+
+        [Fact]
+        public void ErrorContextShouldProvideAccurateInformation()
+        {
+            var engine = new DelimitedFileEngine(
+                layout,
+                A.Fake<IDelimitedLineBuilderFactory>(),
+                lineParserFactory,
+                HandleError);
+
+            using (var stream = new MemoryStream(Encoding.Default.GetBytes(TestData)))
+                engine.Read<Record>(stream).ToList();
+
+            Assert.Equal(3, errorContexts.Count);
+            Assert.Equal(new[] { 1, 2, 3 }, errorContexts.Select(ctx => ctx.LineNumber));
+            Assert.Equal(TestData.Split(new[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries), errorContexts.Select(ctx => ctx.Line));
+            Assert.All(errorContexts, ctx => Assert.Equal("Parsing failed!", ctx.Exception.Message));
+        }
+
+        [Fact]
+        public void MultiEngineErrorContextShouldProvideAccurateInformation()
+        {
+            var engine = new DelimitedFileMultiEngine(
+                new[] { layout },
+                l => typeof(Record),
+                A.Fake<IDelimitedLineBuilderFactory>(),
+                lineParserFactory,
+                HandleError);
+
+            using (var stream = new MemoryStream(Encoding.Default.GetBytes(TestData)))
+                engine.Read(stream);
+
+            Assert.Equal(3, errorContexts.Count);
+            Assert.Equal(new[] { 1, 2, 3 }, errorContexts.Select(ctx => ctx.LineNumber));
+            Assert.Equal(TestData.Split(new[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries), errorContexts.Select(ctx => ctx.Line));
+            Assert.All(errorContexts, ctx => Assert.Equal("Parsing failed!", ctx.Exception.Message));
+        }
+
+        private bool HandleError(FlatFileErrorContext context)
+        {
+            errorContexts.Add(context);
+            return true;
+        }
+
+        private class FakeLineParser : IDelimitedLineParser
+        {
+            public TEntity ParseLine<TEntity>(string line, TEntity entity) where TEntity : new()
+            {
+                throw new Exception("Parsing failed!");
+            }
+        }
+
+        private class Record { }
+    }
+}