godot/modules/mono/editor/Godot.NET.Sdk/Godot.SourceGenerators/ScriptSerializationGenerator.cs

using System.Linq;
using System.Text;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Text;

namespace Godot.SourceGenerators
{
    [Generator]
    public class ScriptSerializationGenerator : ISourceGenerator
    {
        public void Initialize(GeneratorInitializationContext context)
        {
        }

        public void Execute(GeneratorExecutionContext context)
        {
            if (context.AreGodotSourceGeneratorsDisabled())
                return;

            INamedTypeSymbol[] godotClasses = context
                .Compilation.SyntaxTrees
                .SelectMany(tree =>
                    tree.GetRoot().DescendantNodes()
                        .OfType<ClassDeclarationSyntax>()
                        .SelectGodotScriptClasses(context.Compilation)
                        // Report and skip non-partial classes
                        .Where(x =>
                        {
                            if (x.cds.IsPartial())
                            {
                                if (x.cds.IsNested() && !x.cds.AreAllOuterTypesPartial(out var typeMissingPartial))
                                {
                                    Common.ReportNonPartialGodotScriptOuterClass(context, typeMissingPartial!);
                                    return false;
                                }

                                return true;
                            }

                            Common.ReportNonPartialGodotScriptClass(context, x.cds, x.symbol);
                            return false;
                        })
                        .Select(x => x.symbol)
                )
                .Distinct<INamedTypeSymbol>(SymbolEqualityComparer.Default)
                .ToArray();

            if (godotClasses.Length > 0)
            {
                var typeCache = new MarshalUtils.TypeCache(context);

                foreach (var godotClass in godotClasses)
                {
                    VisitGodotScriptClass(context, typeCache, godotClass);
                }
            }
        }

        private static void VisitGodotScriptClass(
            GeneratorExecutionContext context,
            MarshalUtils.TypeCache typeCache,
            INamedTypeSymbol symbol
        )
        {
            INamespaceSymbol namespaceSymbol = symbol.ContainingNamespace;
            string classNs = namespaceSymbol != null && !namespaceSymbol.IsGlobalNamespace ?
                namespaceSymbol.FullQualifiedName() :
                string.Empty;
            bool hasNamespace = classNs.Length != 0;

            bool isInnerClass = symbol.ContainingType != null;

            string uniqueHint = symbol.FullQualifiedName().SanitizeQualifiedNameForUniqueHint()
                                + "_ScriptSerialization_Generated";

            var source = new StringBuilder();

            source.Append("using Godot;\n");
            source.Append("using Godot.NativeInterop;\n");
            source.Append("\n");

            if (hasNamespace)
            {
                source.Append("namespace ");
                source.Append(classNs);
                source.Append(" {\n\n");
            }

            if (isInnerClass)
            {
                var containingType = symbol.ContainingType;

                while (containingType != null)
                {
                    source.Append("partial ");
                    source.Append(containingType.GetDeclarationKeyword());
                    source.Append(" ");
                    source.Append(containingType.NameWithTypeParameters());
                    source.Append("\n{\n");

                    containingType = containingType.ContainingType;
                }
            }

            source.Append("partial class ");
            source.Append(symbol.NameWithTypeParameters());
            source.Append("\n{\n");

            var members = symbol.GetMembers();

            var propertySymbols = members
                .Where(s => !s.IsStatic && s.Kind == SymbolKind.Property)
                .Cast<IPropertySymbol>();

            var fieldSymbols = members
                .Where(s => !s.IsStatic && s.Kind == SymbolKind.Field && !s.IsImplicitlyDeclared)
                .Cast<IFieldSymbol>();

            var godotClassProperties = propertySymbols.WhereIsGodotCompatibleType(typeCache).ToArray();
            var godotClassFields = fieldSymbols.WhereIsGodotCompatibleType(typeCache).ToArray();

            source.Append(
                "    protected override void SaveGodotObjectData(global::Godot.Bridge.GodotSerializationInfo info)\n    {\n");
            source.Append("        base.SaveGodotObjectData(info);\n");

            foreach (var property in godotClassProperties)
            {
                string propertyName = property.PropertySymbol.Name;

                source.Append("        info.AddProperty(GodotInternal.PropName_")
                    .Append(propertyName)
                    .Append(", this.")
                    .Append(propertyName)
                    .Append(");\n");
            }

            foreach (var field in godotClassFields)
            {
                string fieldName = field.FieldSymbol.Name;

                source.Append("        info.AddProperty(GodotInternal.PropName_")
                    .Append(fieldName)
                    .Append(", this.")
                    .Append(fieldName)
                    .Append(");\n");
            }

            source.Append("    }\n");

            source.Append(
                "    protected override void RestoreGodotObjectData(global::Godot.Bridge.GodotSerializationInfo info)\n    {\n");
            source.Append("        base.RestoreGodotObjectData(info);\n");

            foreach (var property in godotClassProperties)
            {
                string propertyName = property.PropertySymbol.Name;
                string propertyTypeQualifiedName = property.PropertySymbol.Type.FullQualifiedName();

                source.Append("        if (info.TryGetProperty<")
                    .Append(propertyTypeQualifiedName)
                    .Append(">(GodotInternal.PropName_")
                    .Append(propertyName)
                    .Append(", out var _value_")
                    .Append(propertyName)
                    .Append("))\n")
                    .Append("            this.")
                    .Append(propertyName)
                    .Append(" = _value_")
                    .Append(propertyName)
                    .Append(";\n");
            }

            foreach (var field in godotClassFields)
            {
                string fieldName = field.FieldSymbol.Name;
                string fieldTypeQualifiedName = field.FieldSymbol.Type.FullQualifiedName();

                source.Append("        if (info.TryGetProperty<")
                    .Append(fieldTypeQualifiedName)
                    .Append(">(GodotInternal.PropName_")
                    .Append(fieldName)
                    .Append(", out var _value_")
                    .Append(fieldName)
                    .Append("))\n")
                    .Append("            this.")
                    .Append(fieldName)
                    .Append(" = _value_")
                    .Append(fieldName)
                    .Append(";\n");
            }

            source.Append("    }\n");

            source.Append("}\n"); // partial class

            if (isInnerClass)
            {
                var containingType = symbol.ContainingType;

                while (containingType != null)
                {
                    source.Append("}\n"); // outer class

                    containingType = containingType.ContainingType;
                }
            }

            if (hasNamespace)
            {
                source.Append("\n}\n");
            }

            context.AddSource(uniqueHint, SourceText.From(source.ToString(), Encoding.UTF8));
        }
    }
}