feat: runtime comment provider

Tomlet.Tests/CommentProvider/TestInlineCommentProvider.cs

@@ -0,0 +1,20 @@
+using System.Collections.Generic;
+
+namespace Tomlet.Tests.CommentProvider;
+
+public class TestInlineCommentProvider : ICommentProvider
+{
+    public static Dictionary<string, string> Comments = new Dictionary<string, string>();
+
+    private readonly string _name;
+
+    public TestInlineCommentProvider(string name)
+    {
+        _name = name;
+    }
+
+    public string GetComment()
+    {
+        return Comments[_name];
+    }
+}

Tomlet.Tests/CommentProvider/TestPrecedingCommentProvider.cs

@@ -0,0 +1,20 @@
+using System.Collections.Generic;
+
+namespace Tomlet.Tests.CommentProvider;
+
+public class TestPrecedingCommentProvider : ICommentProvider
+{
+    public static Dictionary<string, string> Comments = new Dictionary<string, string>();
+
+    private readonly string _name;
+
+    public TestPrecedingCommentProvider(string name)
+    {
+        _name = name;
+    }
+
+    public string GetComment()
+    {
+        return Comments[_name];
+    }
+}

Tomlet.Tests/CommentSerializationTests.cs

@@ -1,4 +1,6 @@
+using System;
 using Tomlet.Models;
+using Tomlet.Tests.CommentProvider;
 using Tomlet.Tests.TestModelClasses;
 using Xunit;
 
@@ -72,7 +74,7 @@ public void CommentsOnTableArraysWork()
         tomlString.Comments.InlineComment = "Inline comment on value";
         table.PutValue("key", tomlString);
 
-        var tableArray = new TomlArray {table};
+        var tableArray = new TomlArray { table };
         tableArray.Comments.PrecedingComment = "This is a preceding comment on the table-array itself";
 
         doc.PutValue("table-array", tableArray);
@@ -91,7 +93,7 @@ public void CommentsOnTableArraysWork()
     public void CommentsOnPrimitiveArraysWork()
     {
         var doc = TomlDocument.CreateEmpty();
-        var tomlNumbers = new TomlArray {1, 2, 3};
+        var tomlNumbers = new TomlArray { 1, 2, 3 };
         doc.PutValue("numbers", tomlNumbers);
 
         tomlNumbers[0].Comments.PrecedingComment = "This is a preceding comment on the first value of the array";
@@ -103,7 +105,7 @@ public void CommentsOnPrimitiveArraysWork()
     2, # This is an inline comment on the second value of the array
     3,
 ]".ReplaceLineEndings();
-        
+
         //Replace tabs with spaces because this source file uses spaces
         var actual = doc.SerializedValue.Trim().Replace("\t", "    ").ReplaceLineEndings();
         Assert.Equal(expected, actual);
@@ -115,10 +117,33 @@ public void CommentAttributesWork()
         var config = TomletMain.To<ExampleMailboxConfigClass>(TestResources.ExampleMailboxConfigurationTestInput);
 
         var doc = TomletMain.DocumentFrom(config);
-        
+
         Assert.Equal("The name of the mailbox", doc.GetValue("mailbox").Comments.InlineComment);
         Assert.Equal("Your username for the mailbox", doc.GetValue("username").Comments.InlineComment);
         Assert.Equal("The password you use to access the mailbox", doc.GetValue("password").Comments.InlineComment);
         Assert.Equal("The rules for the mailbox follow", doc.GetArray("rules").Comments.PrecedingComment);
     }
+
+    [Fact]
+    public void CommentProviderTest()
+    {
+        TestPrecedingCommentProvider.Comments["PrecedingComment"] = Guid.NewGuid().ToString();
+        TestInlineCommentProvider.Comments["InlineComment"] = Guid.NewGuid().ToString();
+
+        var data = new CommentProviderTestModel()
+        {
+            PrecedingComment = "Dynamic Preceding Comment",
+            InlineComment = "Inline Comment",
+        };
+
+        var doc = TomletMain.DocumentFrom(data);
+
+        Assert.Equal(TestPrecedingCommentProvider.Comments["PrecedingComment"],
+            doc.GetValue("PrecedingComment").Comments.PrecedingComment);
+        Assert.Equal("PlainInlineComment", doc.GetValue("PrecedingComment").Comments.InlineComment);
+
+        Assert.Equal(TestInlineCommentProvider.Comments["InlineComment"],
+            doc.GetValue("InlineComment").Comments.InlineComment);
+        Assert.Equal("PlainPrecedingComment", doc.GetValue("InlineComment").Comments.PrecedingComment);
+    }
 }

Tomlet.Tests/TestModelClasses/CommentProviderTestModel.cs

@@ -0,0 +1,15 @@
+using Tomlet.Attributes;
+using Tomlet.Tests.CommentProvider;
+
+namespace Tomlet.Tests.TestModelClasses;
+
+public class CommentProviderTestModel
+{
+    [TomlPrecedingCommentProvider(typeof(TestPrecedingCommentProvider), new object[] { "PrecedingComment" })]
+    [TomlInlineComment("PlainInlineComment")]
+    public string PrecedingComment { get; set; }
+
+    [TomlInlineCommentProvider(typeof(TestInlineCommentProvider), new object[] { "InlineComment" })]
+    [TomlPrecedingComment("PlainPrecedingComment")]
+    public string InlineComment { get; set; }
+}

Tomlet/Attributes/TomlCommentProviderAttribute.cs

@@ -0,0 +1,33 @@
+using System;
+using System.Linq;
+
+namespace Tomlet.Attributes;
+
+[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property)]
+public class TomlCommentProviderAttribute : Attribute
+{
+    private readonly Type _provider;
+    private readonly object[] _args;
+    private readonly Type[] _constructorParamsType;
+
+    public string GetComment()
+    {
+        var constructor = _provider.GetConstructor(_constructorParamsType) ??
+                          throw new ArgumentException("Fail to get a constructor matching the parameters");
+        var instance = constructor.Invoke(_args) as ICommentProvider ??
+                       throw new Exception("Fail to create an instance of the provider");
+        return instance.GetComment();
+    }
+
+    public TomlCommentProviderAttribute(Type provider, object[] args)
+    {
+        if (!typeof(ICommentProvider).IsAssignableFrom(provider))
+        {
+            throw new ArgumentException("Provider must implement ICommentProvider");
+        }
+
+        _provider = provider;
+        _args = args ?? new object[] { };
+        _constructorParamsType = args?.Select(a => a.GetType()).ToArray() ?? new Type[] { };
+    }
+}

Tomlet/Attributes/TomlInlineCommentAttribute.cs

@@ -3,12 +3,10 @@
 namespace Tomlet.Attributes;
 
 [AttributeUsage(AttributeTargets.Field | AttributeTargets.Property)]
-public class TomlInlineCommentAttribute : Attribute
+public class TomlInlineCommentAttribute : TomlInlineCommentProviderAttribute
 {
-    internal string Comment { get; }
-
-    public TomlInlineCommentAttribute(string comment)
+    public TomlInlineCommentAttribute(string comment) : base(typeof(TomlSimpleCommentProvider),
+        new object[] { comment })
     {
-        Comment = comment;
     }
 }

Tomlet/Attributes/TomlInlineCommentProviderAttribute.cs

@@ -0,0 +1,15 @@
+using System;
+
+namespace Tomlet.Attributes;
+
+[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property)]
+public class TomlInlineCommentProviderAttribute : TomlCommentProviderAttribute
+{
+    public TomlInlineCommentProviderAttribute(Type provider) : base(provider, new object[] { })
+    {
+    }
+
+    public TomlInlineCommentProviderAttribute(Type provider, object[] args) : base(provider, args)
+    {
+    }
+}

Tomlet/Attributes/TomlPrecedingCommentAttribute.cs

@@ -3,12 +3,10 @@
 namespace Tomlet.Attributes;
 
 [AttributeUsage(AttributeTargets.Field | AttributeTargets.Property)]
-public class TomlPrecedingCommentAttribute : Attribute
+public class TomlPrecedingCommentAttribute : TomlPrecedingCommentProviderAttribute
 {
-    internal string Comment { get; }
-
-    public TomlPrecedingCommentAttribute(string comment)
+    public TomlPrecedingCommentAttribute(string comment) : base(typeof(TomlSimpleCommentProvider),
+        new object[] { comment })
     {
-        Comment = comment;
     }
 }

Tomlet/Attributes/TomlPrecedingCommentProviderAttribute.cs

@@ -0,0 +1,15 @@
+using System;
+
+namespace Tomlet.Attributes;
+
+[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property)]
+public class TomlPrecedingCommentProviderAttribute : TomlCommentProviderAttribute
+{
+    public TomlPrecedingCommentProviderAttribute(Type provider) : base(provider, new object[] { })
+    {
+    }
+
+    public TomlPrecedingCommentProviderAttribute(Type provider, object[] args) : base(provider, args)
+    {
+    }
+}

Tomlet/CommentProviderUtil.cs

@@ -0,0 +1,18 @@
+using System;
+
+namespace Tomlet;
+
+internal static class CommentProviderUtil
+{
+    public static string GetComment(Type provider)
+    {
+        var constructor = provider.GetConstructor(Type.EmptyTypes);
+        if (constructor == null)
+        {
+            throw new ArgumentException("Provider must have a parameterless constructor");
+        }
+
+        var instance = (ICommentProvider)constructor.Invoke(null);
+        return instance.GetComment();
+    }
+}

Tomlet/Extensions/GenericExtensions.cs

@@ -148,7 +148,8 @@ public static void Deconstruct<TKey, TValue>(this KeyValuePair<TKey, TValue> pai
 
         public static bool IsNullOrWhiteSpace(this string s) => string.IsNullOrEmpty(s) || string.IsNullOrEmpty(s.Trim());
 
-        internal static T? GetCustomAttribute<T>(this MemberInfo info) where T : Attribute => info.GetCustomAttributes(false).Where(a => a is T).Cast<T>().FirstOrDefault();
+        internal static T? GetCustomAttribute<T>(this MemberInfo info) where T : Attribute 
+            => info.GetCustomAttributes(false).Where(a => typeof(T).IsAssignableFrom(a.GetType())).Cast<T>().FirstOrDefault();
 
         internal static void EnsureLegalChar(this int c, int currentLineNum)
         {

Tomlet/ICommentProvider.cs

@@ -0,0 +1,6 @@
+namespace Tomlet;
+
+public interface ICommentProvider
+{
+    public string GetComment();
+}

Tomlet/TomlCompositeSerializer.cs

@@ -29,11 +29,22 @@ public static TomlSerializationMethods.Serialize<object> For(Type type, TomlSeri
 
             var fields = type.GetFields(memberFlags);
             var fieldAttribs = fields
-                .ToDictionary(f => f, f => new {inline = GenericExtensions.GetCustomAttribute<TomlInlineCommentAttribute>(f), preceding = GenericExtensions.GetCustomAttribute<TomlPrecedingCommentAttribute>(f), noInline = GenericExtensions.GetCustomAttribute<TomlDoNotInlineObjectAttribute>(f)});
+                .ToDictionary(f => f, f => new
+                {
+                    inline = GenericExtensions.GetCustomAttribute<TomlInlineCommentProviderAttribute>(f), 
+                    preceding = GenericExtensions.GetCustomAttribute<TomlPrecedingCommentProviderAttribute>(f), 
+                    noInline = GenericExtensions.GetCustomAttribute<TomlDoNotInlineObjectAttribute>(f)
+                });
             var props = type.GetProperties(memberFlags)
                 .ToArray();
             var propAttribs = props
-                .ToDictionary(p => p, p => new {inline = GenericExtensions.GetCustomAttribute<TomlInlineCommentAttribute>(p), preceding = GenericExtensions.GetCustomAttribute<TomlPrecedingCommentAttribute>(p), prop = GenericExtensions.GetCustomAttribute<TomlPropertyAttribute>(p), noInline = GenericExtensions.GetCustomAttribute<TomlDoNotInlineObjectAttribute>(p)});
+                .ToDictionary(p => p, p => new
+                {
+                    inline = GenericExtensions.GetCustomAttribute<TomlInlineCommentProviderAttribute>(p), 
+                    preceding = GenericExtensions.GetCustomAttribute<TomlPrecedingCommentProviderAttribute>(p), 
+                    prop = GenericExtensions.GetCustomAttribute<TomlPropertyAttribute>(p), 
+                    noInline = GenericExtensions.GetCustomAttribute<TomlDoNotInlineObjectAttribute>(p)
+                });
 
             var isForcedNoInline = GenericExtensions.GetCustomAttribute<TomlDoNotInlineObjectAttribute>(type) != null;
 
@@ -75,8 +86,8 @@ public static TomlSerializationMethods.Serialize<object> For(Type type, TomlSeri
                         //in its supertype. 
                         continue;
 
-                    tomlValue.Comments.InlineComment = commentAttribs.inline?.Comment;
-                    tomlValue.Comments.PrecedingComment = commentAttribs.preceding?.Comment;
+                    tomlValue.Comments.InlineComment = commentAttribs.inline?.GetComment();
+                    tomlValue.Comments.PrecedingComment = commentAttribs.preceding?.GetComment();
 
                     if(commentAttribs.noInline != null && tomlValue is TomlTable table)
                         table.ForceNoInline = true;
@@ -104,8 +115,8 @@ public static TomlSerializationMethods.Serialize<object> For(Type type, TomlSeri
 
                     var thisPropAttribs = propAttribs[prop];
 
-                    tomlValue.Comments.InlineComment = thisPropAttribs.inline?.Comment;
-                    tomlValue.Comments.PrecedingComment = thisPropAttribs.preceding?.Comment;
+                    tomlValue.Comments.InlineComment = thisPropAttribs.inline?.GetComment();
+                    tomlValue.Comments.PrecedingComment = thisPropAttribs.preceding?.GetComment();
 
                     if (thisPropAttribs.noInline != null && tomlValue is TomlTable table)
                         table.ForceNoInline = true;

Tomlet/TomlSimpleCommentProvider.cs

@@ -0,0 +1,16 @@
+namespace Tomlet;
+
+internal class TomlSimpleCommentProvider : ICommentProvider
+{
+    private readonly string _comment;
+
+    public TomlSimpleCommentProvider(string comment)
+    {
+        _comment = comment;
+    }
+
+    public string GetComment()
+    {
+        return _comment;
+    }
+}