Simplify empty collections

AndriySvyryd · Jun 16, 2022 · f9d834b · f9d834b
1 parent 9d052bf
commit f9d834b
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Showing 8 changed files with 104 additions and 51 deletions.
diff --git a/src/CSharpScriptSerializer/ArrayCSScriptSerializer.cs b/src/CSharpScriptSerializer/ArrayCSScriptSerializer.cs
@@ -1,8 +1,10 @@
 using System;
+using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Linq;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
+using static Microsoft.CodeAnalysis.CSharp.SyntaxFactory;
 
 namespace CSharpScriptSerialization
 {
@@ -14,15 +16,31 @@ public ArrayCSScriptSerializer(Type type)
         }
 
         public override ExpressionSyntax GetCreation(object obj)
-            => SyntaxFactory.ArrayCreationExpression((ArrayTypeSyntax)GetTypeSyntax(Type))
-                .WithInitializer(AddNewLine(
-                    GetArrayInitializerExpression((Array)obj, startingDimension: 0, indices: ImmutableArray<int>.Empty)));
+        {
+            var array = (Array)obj;
+            return array.Length == 0
+                ? ArrayCreationExpression(ArrayType(GetTypeSyntax(GetArrayElementType(Type)),
+                    List(GetEmptyArrayRanks(Type))))
+                : ArrayCreationExpression((ArrayTypeSyntax)GetTypeSyntax(Type)).WithInitializer(AddNewLine(
+                    GetArrayInitializerExpression(array, startingDimension: 0, indices: ImmutableArray<int>.Empty)));
+        }
+
+        private static IEnumerable<ArrayRankSpecifierSyntax> GetEmptyArrayRanks(Type type)
+            => new[]
+                {
+                    ArrayRankSpecifier(
+                        SeparatedList<ExpressionSyntax>(
+                            ToCommaSeparatedList(                            
+                                Enumerable.Repeat(LiteralExpression(SyntaxKind.NumericLiteralExpression, Literal(0)),
+                                    type.GetArrayRank()))))
+                }
+                .Concat(GetArrayRanks(type.GetElementType()));
 
         private InitializerExpressionSyntax GetArrayInitializerExpression
             (Array array, int startingDimension, ImmutableArray<int> indices)
-            => SyntaxFactory.InitializerExpression(
+            => InitializerExpression(
                 SyntaxKind.ArrayInitializerExpression,
-                SyntaxFactory.SeparatedList<ExpressionSyntax>(
+                SeparatedList<ExpressionSyntax>(
                     ToCommaSeparatedList(Enumerable.Range(
                         array.GetLowerBound(startingDimension),
                         array.GetUpperBound(startingDimension) - array.GetLowerBound(startingDimension) + 1)

diff --git a/src/CSharpScriptSerializer/CSScriptSerializer.cs b/src/CSharpScriptSerializer/CSScriptSerializer.cs
@@ -527,17 +527,19 @@ private static NameSyntax GetNameSyntax(Type type, List<Type> genericArguments)
             return QualifiedName(GetNameSyntax(declaringType, declaringTypeGenericArguments), simpleName);
         }
 
-        private static Type GetArrayElementType(Type type)
+        protected static Type GetArrayElementType(Type type)
             => type.IsArray ? GetArrayElementType(type.GetElementType()) : type;
 
-        private static IEnumerable<ArrayRankSpecifierSyntax> GetArrayRanks(Type type)
+        protected static IEnumerable<ArrayRankSpecifierSyntax> GetArrayRanks(Type type)
             => type == null || !type.IsArray
                 ? Enumerable.Empty<ArrayRankSpecifierSyntax>()
-                : Enumerable.Repeat(ArrayRankSpecifier(
-                    SeparatedList<ExpressionSyntax>(
-                        ToCommaSeparatedList(
-                            Enumerable.Repeat(OmittedArraySizeExpression(), type.GetArrayRank())))),
-                    count: 1)
+                : new[]
+                    {
+                        ArrayRankSpecifier(
+                            SeparatedList<ExpressionSyntax>(
+                                ToCommaSeparatedList(
+                                    Enumerable.Repeat(OmittedArraySizeExpression(), type.GetArrayRank()))))
+                    }
                     .Concat(GetArrayRanks(type.GetElementType()));
 
         protected static TSyntax AddNewLine<TSyntax>(TSyntax expression)

diff --git a/src/CSharpScriptSerializer/CSharpScriptSerializer.csproj b/src/CSharpScriptSerializer/CSharpScriptSerializer.csproj
@@ -5,7 +5,7 @@
     <PackageId>CSharpScriptSerializer</PackageId>
     <AssemblyTitle>CSharpScriptSerializer</AssemblyTitle>
     <Title>CSharpScriptSerializer</Title>
-    <VersionPrefix>3.0.2</VersionPrefix>
+    <VersionPrefix>3.0.3</VersionPrefix>
     <TargetFrameworks>netstandard2.1</TargetFrameworks>
     <NetStandardImplicitPackageVersion>2.0.3</NetStandardImplicitPackageVersion>
     <TreatWarningsAsErrors>True</TreatWarningsAsErrors>
@@ -15,6 +15,8 @@
     <PackageTags>Roslyn;CSharp;C#;CSX;Script;Serialization</PackageTags>
     <PackageReleaseNotes>
       <![CDATA[
+Version 3.0.3
+* Simplify empty collections
 Version 3.0.2
 * Remove trailing new line
 Version 3.0.0
@@ -29,10 +31,6 @@ Version 1.5.0
 * Update to Roslyn V2.8.0
 Version 1.4.0
 * Add support for ValueTuple, Type and plain Object
-Version 1.3.0
-* Update to Roslyn V2.3.1
-Version 1.2.0
-* Update to Roslyn V2
 ]]>
     </PackageReleaseNotes>
     <PackageProjectUrl>https://github.com/AndriySvyryd/CSharpScriptSerializer</PackageProjectUrl>

diff --git a/src/CSharpScriptSerializer/CollectionCSScriptSerializer.cs b/src/CSharpScriptSerializer/CollectionCSScriptSerializer.cs
@@ -87,13 +87,19 @@ public CollectionCSScriptSerializer(
         public override ExpressionSyntax GetCreation(object obj) => GetObjectCreationExpression((T)obj);
 
         protected override ObjectCreationExpressionSyntax GetObjectCreationExpression(T obj)
-            => base.GetObjectCreationExpression(obj)
-                .WithInitializer(AddNewLine(
-                    SyntaxFactory.InitializerExpression(
-                        SyntaxKind.CollectionInitializerExpression,
-                        SyntaxFactory.SeparatedList<ExpressionSyntax>(
-                            ToCommaSeparatedList(_getEnumerable(obj)
-                                .Select(GetElementExpression))))));
+        {
+            var list = _getEnumerable(obj).ToList();
+            return list.Count == 0
+                ? base.GetObjectCreationExpression(obj)
+                    .WithArgumentList(SyntaxFactory.ArgumentList())
+                : base.GetObjectCreationExpression(obj)
+                    .WithInitializer(AddNewLine(
+                        SyntaxFactory.InitializerExpression(
+                            SyntaxKind.CollectionInitializerExpression,
+                            SyntaxFactory.SeparatedList<ExpressionSyntax>(
+                                ToCommaSeparatedList(list
+                                    .Select(GetElementExpression))))));
+        }
 
         protected virtual ExpressionSyntax GetElementExpression(object element)
             => _elementDecomposers == null

diff --git a/src/CSharpScriptSerializer/ConstructorCSScriptSerializer.cs b/src/CSharpScriptSerializer/ConstructorCSScriptSerializer.cs
@@ -30,9 +30,12 @@ public ConstructorCSScriptSerializer(IReadOnlyCollection<Func<T, object>> constr
         public override ExpressionSyntax GetCreation(object obj) => GetObjectCreationExpression((T)obj);
 
         protected virtual ObjectCreationExpressionSyntax GetObjectCreationExpression(T obj)
+            => GetObjectCreationExpression(obj, GenerateEmptyArgumentList);
+
+        protected virtual ObjectCreationExpressionSyntax GetObjectCreationExpression(T obj, bool generateEmptyArgumentList)
             => _constructorParameterGetters == null
                || _constructorParameterGetters.Count == 0
-                ? GenerateEmptyArgumentList
+                ? generateEmptyArgumentList
                     ? GetObjectCreationExpression().WithArgumentList(SyntaxFactory.ArgumentList())
                     : GetObjectCreationExpression()
                 : GetObjectCreationExpression()
@@ -43,7 +46,6 @@ protected virtual ObjectCreationExpressionSyntax GetObjectCreationExpression(T o
                                     SyntaxFactory.Argument(GetCreationExpression(a(obj)))))))));
 
         protected virtual ObjectCreationExpressionSyntax GetObjectCreationExpression()
-            => _objectCreationExpression ??
-               (_objectCreationExpression = SyntaxFactory.ObjectCreationExpression(GetTypeSyntax(Type)));
+            =>_objectCreationExpression ??= SyntaxFactory.ObjectCreationExpression(GetTypeSyntax(Type));
     }
 }
diff --git a/src/CSharpScriptSerializer/PropertyCSScriptSerializer.cs b/src/CSharpScriptSerializer/PropertyCSScriptSerializer.cs
@@ -181,17 +181,23 @@ public override ExpressionSyntax GetCreation(object obj)
         }
 
         protected override ObjectCreationExpressionSyntax GetObjectCreationExpression(T obj)
-            => base.GetObjectCreationExpression(obj)
-                .WithInitializer(AddNewLine(
-                    InitializerExpression(
-                        SyntaxKind.ObjectInitializerExpression,
-                        SeparatedList<ExpressionSyntax>(
-                            ToCommaSeparatedList(_propertyData
-                                .Where(p => p.PropertyCondition(obj, p.PropertyValueGetter(obj)))
-                                .Select(p => AssignmentExpression(
-                                    SyntaxKind.SimpleAssignmentExpression,
-                                    IdentifierName(p.PropertyName),
-                                    GetCreationExpression(p.PropertyValueGetter(obj)))))))));
+        {
+            var properties = _propertyData
+                .Where(p => p.PropertyCondition(obj, p.PropertyValueGetter(obj)))
+                .Select(p => AssignmentExpression(
+                    SyntaxKind.SimpleAssignmentExpression,
+                    IdentifierName(p.PropertyName),
+                    GetCreationExpression(p.PropertyValueGetter(obj)))).ToList();
+
+            var expression = base.GetObjectCreationExpression(obj, generateEmptyArgumentList: properties.Count == 0)
+                    .WithInitializer(AddNewLine(
+                        InitializerExpression(
+                            SyntaxKind.ObjectInitializerExpression,
+                            SeparatedList<ExpressionSyntax>(
+                                ToCommaSeparatedList(properties)))));
+
+            return expression;
+        }
 
         protected static Func<T, object> CreatePropertyValueGetter(PropertyInfo property)
         {

diff --git a/test/CSharpScriptSerializer.Tests/NegativeScenarioTest.cs b/test/CSharpScriptSerializer.Tests/NegativeScenarioTest.cs
@@ -7,7 +7,7 @@ namespace CSharpScriptSerialization.Tests
     public class NegativeScenarioTest
     {
         [Fact]
-        public void NousableProperties()
+        public void NoUsableProperties()
         {
             var input = new Private();
 

diff --git a/test/CSharpScriptSerializer.Tests/RoundTrippingTest.cs b/test/CSharpScriptSerializer.Tests/RoundTrippingTest.cs
@@ -169,17 +169,13 @@ public void CombinedFlagsEnum()
                 + typeof(RoundtrippingTest).Name + "." + typeof(FlagsEnum).Name + "." + FlagsEnum.SecondAndThird, script);
         }
 
-        [Fact]
-        public void VerbatimStrings()
-        {
-            ValidateStringLiteral("\r", verbatim: true);
-            ValidateStringLiteral("\n", verbatim: true);
-            ValidateStringLiteral("\"", verbatim: false);
-            ValidateStringLiteral("@", verbatim: false);
-            ValidateStringLiteral("A", verbatim: false);
-        }
-
-        private void ValidateStringLiteral(string input, bool verbatim)
+        [Theory]
+        [InlineData("\r", true)]
+        [InlineData("\n", true)]
+        [InlineData("\"", false)]
+        [InlineData("@", false)]
+        [InlineData("A", false)]
+        public void VerbatimStrings(string input, bool verbatim)
         {
             var script = CSScriptSerializer.Serialize(input);
             Assert.Equal(verbatim ? '@' : '"', script[0]);
@@ -188,6 +184,16 @@ private void ValidateStringLiteral(string input, bool verbatim)
             Assert.Equal(input, output);
         }
 
+        [Fact]
+        public void EmptyCollections()
+        {
+            Validate(new int?[,] { });
+            Validate(new List<string[]>[] { });
+            Validate(new object[][] { });
+            Validate(new List<string>());
+            Validate(new Dictionary<bool, bool?>());
+        }
+
         [Fact]
         public void LongString()
         {
@@ -211,8 +217,15 @@ public void LongString()
                                                                               17
                                                                               18
                                                                               19";
+
+            Validate(input);
+        }
+
+        private static void Validate<T>(T input)
+        {
             var script = CSScriptSerializer.Serialize(input);
-            var output = CSScriptSerializer.Deserialize<string>(script);
+            var output = CSScriptSerializer.Deserialize<T>(script);
+
             Assert.Equal(input, output);
         }
 
@@ -349,6 +362,14 @@ public void OverridenProperties()
 
             Assert.Equal(input.Property, output.Property);
             Assert.Equal(input.GetSetCount(), output.GetSetCount());
+
+            input = new OverrideDerived();
+
+            script = CSScriptSerializer.Serialize(input);
+            output = CSScriptSerializer.Deserialize<OverrideDerived>(script);
+
+            Assert.Equal(input.Property, output.Property);
+            Assert.Equal(input.GetSetCount(), output.GetSetCount());
         }
 
         public class OverrideDerived : HiddenBase