private void ApppendSource(GeneratorExecutionContext context, StringBuilder sourceBuilder, GenerationDetails generateThis)
{
string propertyName = generateThis.MethodNameNode.Identifier.ValueText;
string dpMemberName = propertyName + "Property";
string dpkMemberName = propertyName + "PropertyKey";
Accessibility dpAccess = generateThis.FieldSymbol.DeclaredAccessibility;
Accessibility dpkAccess = generateThis.FieldSymbol.DeclaredAccessibility;
// If this is a DependencyPropertyKey, then we may need to create the corresponding DependencyProperty field.
// We do this because it's proper to always have a DependencyProperty field & because the DependencyProperty
// field is required when using TemplateBindings in XAML.
if (generateThis.IsDpk)
{
ISymbol?dpMemberSymbol = generateThis.FieldSymbol.ContainingType.GetMembers(dpMemberName).FirstOrDefault();
if (dpMemberSymbol != null)
{
dpAccess = dpMemberSymbol.DeclaredAccessibility;
}
else
{
dpAccess = Accessibility.Public;
// Something like...
// public static readonly DependencyProperty FooProperty = FooPropertyKey.DependencyProperty;
sourceBuilder.Append($@"
public static readonly DependencyProperty {dpMemberName} = {dpkMemberName}.DependencyProperty;" );
}
}
// Try to get the generic type argument (if it exists, this will be the type of the property).
GeneratorOps.TryGetGenericTypeArgument(context, generateThis.MethodNameNode, out ITypeSymbol? genTypeArg);
// We support 0, 1, or 2 arguments. Check for default value and/or flags arguments.
// (A) Gen.Foo<T>()
// (B) Gen.Foo(defaultValue)
// (C) Gen.Foo<T>(flags)
// (D) Gen.Foo(defaultValue, flags)
// The first argument is either the default value or the flags.
// Note: We do not support properties whose default value is `FrameworkPropertyMetadataOptions` because
// it's a niche case that would add code complexity.
ArgumentSyntax?defaultValueArgNode = null;
ITypeSymbol? typeOfFirstArg = null;
bool hasFlags = false;
if (GeneratorOps.TryGetAncestor(generateThis.MethodNameNode, out InvocationExpressionSyntax? invocationExpressionNode))
{
var args = invocationExpressionNode.ArgumentList.Arguments;
if (args.Count > 0)
{
// If the first argument is the flags, then we generate (C); otherwise, we generate (B) or (D).
typeOfFirstArg = GetArgumentType(context, args[0]) ?? this.objTypeSymbol;
if (typeOfFirstArg.Equals(this.flagsTypeSymbol, SymbolEqualityComparer.Default))
{
hasFlags = true;
}
else
{
defaultValueArgNode = args[0];
hasFlags = args.Count > 1;
}
}
}
bool hasDefaultValue = defaultValueArgNode != null;
// Determine the type of the property.
// If there is a generic type argument, then use that; otherwise, use the type of the default value argument.
// As a safety precaution - ensure that the generated code is always valid by defaulting to use `object`.
// But really, if we were unable to get the type, that means the user's code doesn't compile anyhow.
generateThis.PropertyType =
genTypeArg
?? (hasDefaultValue ? typeOfFirstArg : null)
?? this.objTypeSymbol;
generateThis.PropertyTypeName = generateThis.PropertyType.ToDisplayString();
string genClassDecl;
string?moreDox = null;
if (generateThis.IsAttached)
{
string targetTypeName = "DependencyObject";
if (generateThis.MethodNameNode.Parent is MemberAccessExpressionSyntax memberAccessExpr &&
memberAccessExpr.Expression is GenericNameSyntax genClassNameNode)
{
genClassDecl = "GenAttached<__TTarget> where __TTarget : DependencyObject";
if (GeneratorOps.TryGetGenericTypeArgument(context, genClassNameNode, out ITypeSymbol? attachmentNarrowingType))
{
generateThis.AttachmentNarrowingType = attachmentNarrowingType;
targetTypeName = attachmentNarrowingType.ToDisplayString();
moreDox = $@"<br/>This attached property is only for use with objects of type <typeparamref name=""__TTarget""/>.";
}
}
else
{
genClassDecl = "GenAttached";
}
// Write the static get/set methods source code.
string getterAccess = dpAccess.ToString().ToLower();
string setterAccess = generateThis.IsDpk ? dpkAccess.ToString().ToLower() : getterAccess;
string setterArg0 = generateThis.IsDpk ? dpkMemberName : dpMemberName;
// Something like...
// public static int GetFoo(DependencyObject d) => (int)d.GetValue(FooProperty);
// private static void SetFoo(DependencyObject d, int value) => d.SetValue(FooPropertyKey);
sourceBuilder.Append($@"
{getterAccess} static {generateThis.PropertyTypeName} Get{propertyName}({targetTypeName} d) => ({generateThis.PropertyTypeName})d.GetValue({dpMemberName});
{setterAccess} static void Set{propertyName}({targetTypeName} d, {generateThis.PropertyTypeName} value) => d.SetValue({setterArg0}, value);" );
}
public void Execute(GeneratorExecutionContext context)
{
//DebugMe.Go();
this.useNullableContext = (context.ParseOptions as CSharpParseOptions)?.LanguageVersion >= LanguageVersion.CSharp8;
var syntaxReceiver = (SyntaxReceiver)context.SyntaxReceiver !;
// Cast keys to `ISymbol` in the key selector to make the analyzer shutup about CS8602 ("Dereference of a possibly null reference.").
var namespaces = UpdateAndFilterGenerationRequests(context, syntaxReceiver.GenerationRequests)
.GroupBy(g => (ISymbol)g.FieldSymbol.ContainingType, SymbolEqualityComparer.Default)
.GroupBy(g => (ISymbol)g.Key.ContainingNamespace, SymbolEqualityComparer.Default);
StringBuilder sourceBuilder = new();
foreach (var namespaceGroup in namespaces)
{
// Get these type symbols now so we don't waste time finding them each time we need them later.
this.objTypeSymbol ??= context.Compilation.GetTypeByMetadataName("System.Object") !;
this.doTypeSymbol ??= context.Compilation.GetTypeByMetadataName("System.Windows.DependencyObject") !;
this.argsTypeSymbol ??= context.Compilation.GetTypeByMetadataName("System.Windows.DependencyPropertyChangedEventArgs") !;
this.flagsTypeSymbol ??= context.Compilation.GetTypeByMetadataName("System.Windows.FrameworkPropertyMetadataOptions");
this.reTypeSymbol ??= context.Compilation.GetTypeByMetadataName("System.Windows.RoutedEvent");
string namespaceName = namespaceGroup.Key.ToString();
sourceBuilder.Append($@"
namespace {namespaceName}
{{");
foreach (var classGroup in namespaceGroup)
{
string?maybeStatic = classGroup.Key.IsStatic ? "static " : null;
string className = GeneratorOps.GetTypeName((INamedTypeSymbol)classGroup.Key);
sourceBuilder.Append($@"
{maybeStatic}partial class {className}
{{" );
foreach (var generateThis in classGroup)
{
context.CancellationToken.ThrowIfCancellationRequested();
this.ApppendSource(context, sourceBuilder, generateThis);
}
sourceBuilder.Append(@"
}
");
}
sourceBuilder.Append(@"
}
");
}
if (sourceBuilder.Length != 0)
{
string?maybeNullableContext = this.useNullableContext ? "#nullable enable" : null;
sourceBuilder.Insert(0,
$@"//------------------------------------------------------------------------------
// <auto-generated>
// This code was generated by a boilerplatezero (BPZ) source generator.
// Generator = {this.GetType().FullName}
// {Diagnostics.HelpLinkUri}
// </auto-generated>
//------------------------------------------------------------------------------
{maybeNullableContext}
using System.Windows;
");
context.AddSource($"bpz.DependencyProperties.g.cs", sourceBuilder.ToString());
}
}
private void ApppendSource(GeneratorExecutionContext context, StringBuilder sourceBuilder, GenerationDetails generateThis)
{
string eventName = generateThis.MethodNameNode.Identifier.ValueText;
string routedEventMemberName = generateThis.FieldSymbol.Name;
string eventHandlerTypeDoxString = $@"<see cref=""{this.rehTypeSymbol.ToDisplayString()}""/>";
// Try to get the generic type argument (if it exists, this will be the type of the event handler).
if (GeneratorOps.TryGetGenericTypeArgument(context, generateThis.MethodNameNode, out ITypeSymbol? genTypeArg))
{
// If the type is a multicast delegate, then use it;
// otherwise, use the type in a `RoutedPropertyChangedEventHandler<>`.
if (genTypeArg.BaseType?.Equals(this.mdTypeSymbol, SymbolEqualityComparer.Default) ?? false)
{
// Good to go! Documentation can reference the generic type parameter.
eventHandlerTypeDoxString = @"<typeparamref name=""__T""/>";
}
else
{
// Example: Transform `double` into `RoutedPropertyChangedEventHandler<double>`.
genTypeArg = this.rpcehTypeSymbol.Construct(genTypeArg);
// Documentation will appear as something like...
// RoutedPropertyChangedEventHandler<T> of double
string rpcehT = GeneratorOps.ReplaceBrackets(this.rpcehTypeSymbol.ToDisplayString());
eventHandlerTypeDoxString = $@"<see cref=""{rpcehT}""/> of <typeparamref name=""__T""/>";
}
}
// Determine the type of the handler.
// If there is a generic type argument, then use that; otherwise, use `RoutedEventHandler`.
generateThis.EventHandlerType = genTypeArg ?? this.rehTypeSymbol;
generateThis.EventHandlerTypeName = generateThis.EventHandlerType.ToDisplayString();
string genClassDecl;
string?moreDox = null;
if (generateThis.IsAttached)
{
string targetTypeName = "DependencyObject";
string callerExpression = "(d as UIElement)?";
if (generateThis.MethodNameNode.Parent is MemberAccessExpressionSyntax memberAccessExpr &&
memberAccessExpr.Expression is GenericNameSyntax genClassNameNode)
{
genClassDecl = "GenAttached<__TTarget> where __TTarget : DependencyObject";
if (GeneratorOps.TryGetGenericTypeArgument(context, genClassNameNode, out ITypeSymbol? attachmentNarrowingType))
{
generateThis.AttachmentNarrowingType = attachmentNarrowingType;
targetTypeName = attachmentNarrowingType.ToDisplayString();
callerExpression = "d";
moreDox = $@"<br/>This attached event is only for use with objects of type <typeparamref name=""__TTarget""/>.";
}
}
else
{
genClassDecl = "GenAttached";
}
// Write the static get/set methods source code.
string methodsAccess = generateThis.FieldSymbol.DeclaredAccessibility.ToString().ToLower();
// Something like...
// public static void AddFooChangedHandler(DependencyObject d, RoutedPropertyChangedEventHandler<int> handler) => (d as UIElement)?.AddHandler(FooChangedEvent, handler);
// public static void RemoveFooChangedHandler(DependencyObject d, RoutedPropertyChangedEventHandler<int> handler) => (d as UIElement)?.RemoveHandler(FooChangedEvent, handler);
sourceBuilder.Append($@"
{methodsAccess} static void Add{eventName}Handler({targetTypeName} d, {generateThis.EventHandlerTypeName} handler) => {callerExpression}.AddHandler({routedEventMemberName}, handler);
{methodsAccess} static void Remove{eventName}Handler({targetTypeName} d, {generateThis.EventHandlerTypeName} handler) => {callerExpression}.RemoveHandler({routedEventMemberName}, handler);" );
}