Annotate API reference types for nullable awareness

.vscode/settings.json

@@ -13,4 +13,12 @@
         "editor.formatOnType": true
     },
     "prettier.proseWrap": "always",
+    "cSpell.words": [
+        "Conv",
+        "cref",
+        "Dependee",
+        "finalizer",
+        "msgctxt",
+        "Msgid"
+    ],
 }

src/Yarhl.Media/Text/Binary2Po.cs

@@ -45,7 +45,7 @@ public Po Convert(IBinary source)
             Po po = new Po();
 
             // Read the header if any
-            PoEntry entry = ReadEntry(reader);
+            PoEntry? entry = ReadEntry(reader);
             if (entry == null)
                 return po;
 
@@ -62,15 +62,15 @@ public Po Convert(IBinary source)
             return po;
         }
 
-        static PoEntry ReadEntry(TextDataReader reader)
+        static PoEntry? ReadEntry(TextDataReader reader)
         {
             // Skip all the blank lines before the block of text
             string line = string.Empty;
-            while (reader.PeekLine()?.Trim().Length == 0)
+            while (!reader.Stream.EndOfStream && reader.PeekLine().Trim().Length == 0)
                 reader.ReadLine();
 
             // If nothing to read, EOF
-            if (reader.Stream.Position >= reader.Stream.Length)
+            if (reader.Stream.EndOfStream)
                 return null;
 
             PoEntry entry = new PoEntry();

src/Yarhl.Media/Text/Encodings/EscapeOutRangeEncoding.cs

@@ -107,7 +107,7 @@ public override int GetCharCount(byte[] bytes, int index, int count)
         /// <param name="charIndex">Index in the char array.</param>
         /// <param name="charCount">Number of chars to convert.</param>
         /// <param name="bytes">Output byte array.</param>
-        /// <param name="byteIndex">Indes in the byte array.</param>
+        /// <param name="byteIndex">Index in the byte array.</param>
         public override int GetBytes(char[] chars, int charIndex, int charCount, byte[] bytes, int byteIndex)
         {
             if (chars == null)
@@ -206,7 +206,7 @@ static bool MatchSequence(IList<byte> buffer, int index, params byte[] sequence)
             return true;
         }
 
-        static string UnescapeText(string text, ICollection<byte> symbols = null)
+        static string UnescapeText(string text, ICollection<byte>? symbols = null)
         {
             StringBuilder transformed = new StringBuilder(text);
             StringComparison culture = StringComparison.Ordinal;
@@ -265,7 +265,7 @@ public override DecoderFallbackBuffer CreateFallbackBuffer()
         /// </summary>
         internal sealed class EscapeOutRangeDecoderFallbackBuffer : DecoderFallbackBuffer
         {
-            string replacement;
+            string replacement = string.Empty;
             int currentPos;
 
             /// <summary>

src/Yarhl.Media/Text/Encodings/EucJpEncoding.cs

@@ -103,7 +103,7 @@ public override int GetByteCount(char[] chars, int index, int count)
         /// <param name="charIndex">Index in the char array.</param>
         /// <param name="charCount">Number of chars to convert.</param>
         /// <param name="bytes">Output byte array.</param>
-        /// <param name="byteIndex">Indes in the byte array.</param>
+        /// <param name="byteIndex">Index in the byte array.</param>
         public override int GetBytes(char[] chars, int charIndex, int charCount, byte[] bytes, int byteIndex)
         {
             if (chars == null)
@@ -358,15 +358,13 @@ public static Table FromResource(string path)
             {
                 Table table = new Table();
 
-                Stream stream = null;
+                Stream? stream = null;
                 try {
                     stream = Assembly.GetExecutingAssembly()
                         .GetManifestResourceStream(path);
 
                     using (var reader = new StreamReader(stream)) {
-#pragma warning disable IDISP003
                         stream = null;  // Avoid disposing twice
-#pragma warning restore IDISP003
 
                         while (!reader.EndOfStream) {
                             string line = reader.ReadLine();

src/Yarhl.Media/Text/Po.cs

@@ -32,13 +32,13 @@ public class Po : ICloneableFormat
         readonly IList<PoEntry> entries;
         readonly ReadOnlyCollection<PoEntry> readonlyEntries;
         readonly IDictionary<string, PoEntry> searchEntries;
-        PoHeader header;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="Po"/> class.
         /// </summary>
         public Po()
         {
+            Header = new PoHeader();
             entries = new List<PoEntry>();
             readonlyEntries = new ReadOnlyCollection<PoEntry>(entries);
             searchEntries = new Dictionary<string, PoEntry>();
@@ -59,24 +59,8 @@ public Po(PoHeader headerArg)
         /// </summary>
         /// <value>The header.</value>
         public PoHeader Header {
-            get {
-                return header;
-            }
-
-            set {
-                if (value == null) {
-                    header = null;
-                } else {
-                    if (string.IsNullOrEmpty(value.ProjectIdVersion))
-                        throw new FormatException(nameof(value.ProjectIdVersion) + " is empty");
-                    if (string.IsNullOrEmpty(value.ReportMsgidBugsTo))
-                        throw new FormatException(nameof(value.ReportMsgidBugsTo) + " is empty");
-                    if (string.IsNullOrEmpty(value.Language))
-                        throw new FormatException(nameof(value.Language) + " is empty");
-
-                    header = value;
-                }
-            }
+            get;
+            set;
         }
 
         /// <summary>
@@ -125,7 +109,7 @@ public void Add(IEnumerable<PoEntry> items)
         /// <param name="original">Original text from the entry.</param>
         /// <param name="context">Context text from the entry.</param>
         /// <returns>The found entry or null if not found.</returns>
-        public PoEntry FindEntry(string original, string context = null)
+        public PoEntry? FindEntry(string original, string? context = null)
         {
             if (string.IsNullOrEmpty(original))
                 throw new ArgumentNullException(nameof(original));
@@ -137,10 +121,8 @@ public PoEntry FindEntry(string original, string context = null)
         /// <inheritdoc />
         public virtual object DeepClone()
         {
-            Po clone = new Po();
-            if (header != null) {
-                clone.header = new PoHeader(header);
-            }
+            var clonedHeader = new PoHeader(Header);
+            Po clone = new Po(clonedHeader);
 
             foreach (PoEntry entry in entries)
             {
@@ -155,7 +137,7 @@ static string GetKey(PoEntry entry)
             return GetKey(entry.Original, entry.Context);
         }
 
-        static string GetKey(string original, string context)
+        static string GetKey(string original, string? context)
         {
             return original + "||" + (context ?? string.Empty);
         }
@@ -168,7 +150,7 @@ static void MergeEntry(PoEntry current, PoEntry newEntry)
                         "different translations.");
             }
 
-            if (newEntry.Reference != null)
+            if (!string.IsNullOrEmpty(newEntry.Reference))
                 current.Reference += "," + newEntry.Reference;
         }
     }

src/Yarhl.Media/Text/Po2Binary.cs

@@ -31,8 +31,12 @@ public class Po2Binary : IConverter<Po, BinaryFormat>
         /// <summary>
         /// Convert the specified PO into a Binary stream.
         /// </summary>
-        /// <returns>The converted stream.</returns>
         /// <param name="source">Source PO.</param>
+        /// <returns>The converted stream.</returns>
+        /// <remarks>
+        /// It writes the header only if <see cref="PoHeader.ProjectIdVersion"/>
+        /// is not empty.
+        /// </remarks>
         public BinaryFormat Convert(Po source)
         {
             if (source == null)
@@ -41,7 +45,7 @@ public BinaryFormat Convert(Po source)
             BinaryFormat binary = new BinaryFormat();
             TextDataWriter writer = new TextDataWriter(binary.Stream);
 
-            if (source.Header != null)
+            if (!string.IsNullOrEmpty(source.Header.ProjectIdVersion))
                 WriteHeader(source.Header, writer);
 
             foreach (var entry in source.Entries) {

src/Yarhl.Media/Text/PoEntry.cs

@@ -33,13 +33,21 @@ public PoEntry()
         {
             Original = string.Empty;
             Translated = string.Empty;
+            Context = string.Empty;
+            TranslatorComment = string.Empty;
+            ExtractedComments = string.Empty;
+            Reference = string.Empty;
+            Flags = string.Empty;
+            PreviousContext = string.Empty;
+            PreviousOriginal = string.Empty;
         }
 
         /// <summary>
         /// Initializes a new instance of the <see cref="PoEntry"/> class.
         /// </summary>
         /// <param name="original">Original text to translate.</param>
         public PoEntry(string original)
+            : this()
         {
             Original = original;
             Translated = string.Empty;
@@ -69,7 +77,7 @@ public PoEntry(PoEntry entry)
         /// Gets or sets the original content to translate.
         /// </summary>
         /// <remarks>
-        /// <para>Entris with the same original content will be merged.</para>
+        /// <para>Entries with the same original content will be merged.</para>
         /// </remarks>
         /// <value>The original content.</value>
         public string Original { get; set; }

src/Yarhl.Media/Text/PoHeader.cs

@@ -32,6 +32,14 @@ public class PoHeader
         /// </summary>
         public PoHeader()
         {
+            ProjectIdVersion = string.Empty;
+            ReportMsgidBugsTo = string.Empty;
+            Language = string.Empty;
+            CreationDate = DateTime.Now.ToShortDateString();
+            RevisionDate = string.Empty;
+            LastTranslator = string.Empty;
+            LanguageTeam = string.Empty;
+            PluralForms = string.Empty;
             Extensions = new Dictionary<string, string>();
         }
 
@@ -47,7 +55,6 @@ public PoHeader(string id, string reporter, string lang)
             ProjectIdVersion = id;
             ReportMsgidBugsTo = reporter;
             Language = lang;
-            CreationDate = DateTime.Now.ToShortDateString();
         }
 
         /// <summary>

src/Yarhl.Media/Yarhl.Media.csproj

@@ -4,6 +4,8 @@
   <PropertyGroup>
     <Description>Yarhl plugin with support of text converters.</Description>
     <TargetFramework>netstandard2.0</TargetFramework>
+    <LangVersion>10.0</LangVersion>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

src/Yarhl.UnitTests/IO/DataWriterTests.cs

@@ -1091,6 +1091,7 @@ public void WriteObjectsInvalidArguments()
             string nullValue = null;
             Assert.Throws<ArgumentNullException>(() => writer.WriteOfType(nullType, 1));
             Assert.Throws<ArgumentNullException>(() => writer.WriteOfType(typeof(string), nullValue));
+            Assert.Throws<ArgumentNullException>(() => writer.WriteOfType<string>(nullValue));
         }
 
         [Test]

src/Yarhl.UnitTests/IO/StreamFormat/StreamWrapperTests.cs

@@ -36,16 +36,6 @@ public void ConstructorSetProperties()
             Assert.That(wrapper.BaseStream, Is.SameAs(stream));
         }
 
-        [Test]
-        public void FeaturePropertiesDefaults()
-        {
-            using var wrapper = new StreamWrapperImpl();
-            Assert.That(wrapper.CanRead, Is.True);
-            Assert.That(wrapper.CanWrite, Is.True);
-            Assert.That(wrapper.CanSeek, Is.True);
-            Assert.That(wrapper.CanTimeout, Is.False);
-        }
-
         [Test]
         public void FeaturePropertiesFromBaseStream()
         {
@@ -278,10 +268,6 @@ public void TestFlushThrowsIfDisposed()
 
         private sealed class StreamWrapperImpl : StreamWrapper
         {
-            public StreamWrapperImpl()
-            {
-            }
-
             public StreamWrapperImpl(Stream stream)
                 : base(stream)
             {

src/Yarhl.UnitTests/IO/TextDataReaderTests.cs

@@ -366,10 +366,12 @@ public void ReadToTokenWithPreamble()
         }
 
         [Test]
-        public void ReadToTokenWhenEOFReturnsNull()
+        public void ReadToTokenWhenEOFThrows()
         {
             var reader = new TextDataReader(stream);
-            Assert.IsNull(reader.ReadToToken("3"));
+            Assert.That(
+                () => reader.ReadToToken("3"),
+                Throws.InstanceOf<EndOfStreamException>());
         }
 
         [Test]
@@ -608,13 +610,17 @@ public void ReadLineWithoutNewLineDoesNotThrow()
         }
 
         [Test]
-        public void ReadLineWhenEOFReturnsNull()
+        public void ReadLineWhenEOFThrowsException()
         {
             var reader = new TextDataReader(stream);
-            Assert.IsNull(reader.ReadLine());
+            Assert.That(
+                () => reader.ReadLine(),
+                Throws.InstanceOf<EndOfStreamException>());
 
             reader.AutoNewLine = false;
-            Assert.IsNull(reader.ReadLine());
+            Assert.That(
+                () => reader.ReadLine(),
+                Throws.InstanceOf<EndOfStreamException>());
         }
 
         [Test]

src/Yarhl.UnitTests/Media/Text/Po2BinaryTests.cs

@@ -254,7 +254,8 @@ public void ConvertNoHeaderEntries()
             var newPo = ConvertStringToPo(text);
 
             CompareText(ConvertFormat.To<BinaryFormat>(testPo), text);
-            Assert.IsNull(newPo.Header);
+            Assert.That(newPo.Header, Is.Not.Null);
+            Assert.That(newPo.Header.ProjectIdVersion, Is.Empty);
             Assert.AreEqual(2, newPo.Entries.Count);
         }
 

src/Yarhl.UnitTests/Media/Text/PoEntryTests.cs

@@ -30,18 +30,18 @@ public class PoEntryTests
         public void DefaultValues()
         {
             PoEntry entry = new PoEntry();
-            Assert.AreEqual(string.Empty, entry.Original);
-            Assert.AreEqual(string.Empty, entry.Translated);
-            Assert.IsNull(entry.Context);
-            Assert.IsNull(entry.TranslatorComment);
-            Assert.IsNull(entry.ExtractedComments);
-            Assert.IsNull(entry.Reference);
-            Assert.IsNull(entry.Flags);
-            Assert.IsNull(entry.PreviousContext);
-            Assert.IsNull(entry.PreviousOriginal);
+            Assert.That(entry.Original, Is.Empty);
+            Assert.That(entry.Translated, Is.Empty);
+            Assert.That(entry.Context, Is.Empty);
+            Assert.That(entry.TranslatorComment, Is.Empty);
+            Assert.That(entry.ExtractedComments, Is.Empty);
+            Assert.That(entry.Reference, Is.Empty);
+            Assert.That(entry.Flags, Is.Empty);
+            Assert.That(entry.PreviousContext, Is.Empty);
+            Assert.That(entry.PreviousOriginal, Is.Empty);
 
             entry = new PoEntry("original");
-            Assert.AreEqual("original", entry.Original);
+            Assert.That(entry.Original, Is.EqualTo("original"));
         }
 
         [Test]