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Diffstat (limited to 'modules/mono/glue/Managed/Files/DynamicObject.cs')
| -rw-r--r-- | modules/mono/glue/Managed/Files/DynamicObject.cs | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/modules/mono/glue/Managed/Files/DynamicObject.cs b/modules/mono/glue/Managed/Files/DynamicObject.cs new file mode 100644 index 0000000000..a0f105d55e --- /dev/null +++ b/modules/mono/glue/Managed/Files/DynamicObject.cs @@ -0,0 +1,213 @@ + +using System; +using System.Collections.Generic; +using System.Dynamic; +using System.Linq.Expressions; +using System.Runtime.CompilerServices; + +namespace Godot +{ + /// <summary> + /// Represents an <see cref="Godot.Object"/> whose members can be dynamically accessed at runtime through the Variant API. + /// </summary> + /// <remarks> + /// <para> + /// The <see cref="Godot.DynamicGodotObject"/> class enables access to the Variant + /// members of a <see cref="Godot.Object"/> instance at runtime. + /// </para> + /// <para> + /// This allows accessing the class members using their original names in the engine as well as the members from the + /// script attached to the <see cref="Godot.Object"/>, regardless of the scripting language it was written in. + /// </para> + /// </remarks> + /// <example> + /// This sample shows how to use <see cref="Godot.DynamicGodotObject"/> to dynamically access the engine members of a <see cref="Godot.Object"/>. + /// <code> + /// dynamic sprite = GetNode("Sprite").DynamicGodotObject; + /// sprite.add_child(this); + /// + /// if ((sprite.hframes * sprite.vframes) > 0) + /// sprite.frame = 0; + /// </code> + /// </example> + /// <example> + /// This sample shows how to use <see cref="Godot.DynamicGodotObject"/> to dynamically access the members of the script attached to a <see cref="Godot.Object"/>. + /// <code> + /// dynamic childNode = GetNode("ChildNode").DynamicGodotObject; + /// + /// if (childNode.print_allowed) + /// { + /// childNode.message = "Hello from C#"; + /// childNode.print_message(3); + /// } + /// </code> + /// The <c>ChildNode</c> node has the following GDScript script attached: + /// <code> + /// // # ChildNode.gd + /// // var print_allowed = true + /// // var message = "" + /// // + /// // func print_message(times): + /// // for i in times: + /// // print(message) + /// </code> + /// </example> + public class DynamicGodotObject : DynamicObject + { + /// <summary> + /// Gets the <see cref="Godot.Object"/> associated with this <see cref="Godot.DynamicGodotObject"/>. + /// </summary> + public Object Value { get; } + + /// <summary> + /// Initializes a new instance of the <see cref="Godot.DynamicGodotObject"/> class. + /// </summary> + /// <param name="godotObject"> + /// The <see cref="Godot.Object"/> that will be associated with this <see cref="Godot.DynamicGodotObject"/>. + /// </param> + /// <exception cref="System.ArgumentNullException"> + /// Thrown when the <paramref name="godotObject"/> parameter is null. + /// </exception> + public DynamicGodotObject(Object godotObject) + { + if (godotObject == null) + throw new ArgumentNullException(nameof(godotObject)); + + this.Value = godotObject; + } + + public override IEnumerable<string> GetDynamicMemberNames() + { + return godot_icall_DynamicGodotObject_SetMemberList(Object.GetPtr(Value)); + } + + public override bool TryBinaryOperation(BinaryOperationBinder binder, object arg, out object result) + { + switch (binder.Operation) + { + case ExpressionType.Equal: + case ExpressionType.NotEqual: + if (binder.ReturnType == typeof(bool) || binder.ReturnType.IsAssignableFrom(typeof(bool))) + { + if (arg == null) + { + bool boolResult = Object.IsInstanceValid(Value); + + if (binder.Operation == ExpressionType.Equal) + boolResult = !boolResult; + + result = boolResult; + return true; + } + + if (arg is Object other) + { + bool boolResult = (Value == other); + + if (binder.Operation == ExpressionType.NotEqual) + boolResult = !boolResult; + + result = boolResult; + return true; + } + } + + break; + default: + // We're not implementing operators <, <=, >, and >= (LessThan, LessThanOrEqual, GreaterThan, GreaterThanOrEqual). + // These are used on the actual pointers in variant_op.cpp. It's better to let the user do that explicitly. + break; + } + + return base.TryBinaryOperation(binder, arg, out result); + } + + public override bool TryConvert(ConvertBinder binder, out object result) + { + if (binder.Type == typeof(Object)) + { + result = Value; + return true; + } + + if (typeof(Object).IsAssignableFrom(binder.Type)) + { + // Throws InvalidCastException when the cast fails + result = Convert.ChangeType(Value, binder.Type); + return true; + } + + return base.TryConvert(binder, out result); + } + + public override bool TryGetIndex(GetIndexBinder binder, object[] indexes, out object result) + { + if (indexes.Length == 1) + { + if (indexes[0] is string name) + { + return godot_icall_DynamicGodotObject_GetMember(Object.GetPtr(Value), name, out result); + } + } + + return base.TryGetIndex(binder, indexes, out result); + } + + public override bool TryGetMember(GetMemberBinder binder, out object result) + { + return godot_icall_DynamicGodotObject_GetMember(Object.GetPtr(Value), binder.Name, out result); + } + + public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result) + { + return godot_icall_DynamicGodotObject_InvokeMember(Object.GetPtr(Value), binder.Name, args, out result); + } + + public override bool TrySetIndex(SetIndexBinder binder, object[] indexes, object value) + { + if (indexes.Length == 1) + { + if (indexes[0] is string name) + { + return godot_icall_DynamicGodotObject_SetMember(Object.GetPtr(Value), name, value); + } + } + + return base.TrySetIndex(binder, indexes, value); + } + + public override bool TrySetMember(SetMemberBinder binder, object value) + { + return godot_icall_DynamicGodotObject_SetMember(Object.GetPtr(Value), binder.Name, value); + } + + [MethodImpl(MethodImplOptions.InternalCall)] + internal extern static string[] godot_icall_DynamicGodotObject_SetMemberList(IntPtr godotObject); + + [MethodImpl(MethodImplOptions.InternalCall)] + internal extern static bool godot_icall_DynamicGodotObject_InvokeMember(IntPtr godotObject, string name, object[] args, out object result); + + [MethodImpl(MethodImplOptions.InternalCall)] + internal extern static bool godot_icall_DynamicGodotObject_GetMember(IntPtr godotObject, string name, out object result); + + [MethodImpl(MethodImplOptions.InternalCall)] + internal extern static bool godot_icall_DynamicGodotObject_SetMember(IntPtr godotObject, string name, object value); + + #region We don't override these methods + + // Looks like this is not usable from C# + //public override bool TryCreateInstance(CreateInstanceBinder binder, object[] args, out object result); + + // Object members cannot be deleted + //public override bool TryDeleteIndex(DeleteIndexBinder binder, object[] indexes); + //public override bool TryDeleteMember(DeleteMemberBinder binder); + + // Invocation on the object itself, e.g.: obj(param) + //public override bool TryInvoke(InvokeBinder binder, object[] args, out object result); + + // No unnary operations to handle + //public override bool TryUnaryOperation(UnaryOperationBinder binder, out object result); + + #endregion + } +} |