/
RelayCommandGenerator.Execute.cs
1080 lines (954 loc) · 58.9 KB
/
RelayCommandGenerator.Execute.cs
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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Linq;
using System.Threading;
using CommunityToolkit.Mvvm.SourceGenerators.ComponentModel.Models;
using CommunityToolkit.Mvvm.SourceGenerators.Extensions;
using CommunityToolkit.Mvvm.SourceGenerators.Helpers;
using CommunityToolkit.Mvvm.SourceGenerators.Input.Models;
using CommunityToolkit.Mvvm.SourceGenerators.Models;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using static CommunityToolkit.Mvvm.SourceGenerators.Diagnostics.DiagnosticDescriptors;
using static Microsoft.CodeAnalysis.CSharp.SyntaxFactory;
namespace CommunityToolkit.Mvvm.SourceGenerators;
/// <inheritdoc/>
partial class RelayCommandGenerator
{
/// <summary>
/// A container for all the logic for <see cref="RelayCommandGenerator"/>.
/// </summary>
internal static class Execute
{
/// <summary>
/// Processes a given annotated methods and produces command info, if possible.
/// </summary>
/// <param name="methodSymbol">The input <see cref="IMethodSymbol"/> instance to process.</param>
/// <param name="attributeData">The <see cref="AttributeData"/> instance the method was annotated with.</param>
/// <param name="semanticModel">The <see cref="SemanticModel"/> instance for the current run.</param>
/// <param name="token">The cancellation token for the current operation.</param>
/// <param name="commandInfo">The resulting <see cref="CommandInfo"/> instance, if successfully generated.</param>
/// <param name="diagnostics">The resulting diagnostics from the processing operation.</param>
/// <returns>Whether a <see cref="CommandInfo"/> instance could be generated successfully.</returns>
public static bool TryGetInfo(
IMethodSymbol methodSymbol,
AttributeData attributeData,
SemanticModel semanticModel,
CancellationToken token,
[NotNullWhen(true)] out CommandInfo? commandInfo,
out ImmutableArray<DiagnosticInfo> diagnostics)
{
using ImmutableArrayBuilder<DiagnosticInfo> builder = ImmutableArrayBuilder<DiagnosticInfo>.Rent();
// Validate the method definition is unique
if (!IsCommandDefinitionUnique(methodSymbol, builder))
{
goto Failure;
}
token.ThrowIfCancellationRequested();
// Get the command field and property names
(string fieldName, string propertyName) = GetGeneratedFieldAndPropertyNames(methodSymbol);
token.ThrowIfCancellationRequested();
// Get the command type symbols
if (!TryMapCommandTypesFromMethod(
methodSymbol,
in builder,
out string? commandInterfaceType,
out string? commandClassType,
out string? delegateType,
out bool supportsCancellation,
out ImmutableArray<string> commandTypeArguments,
out ImmutableArray<string> commandTypeArgumentsWithNullabilityAnnotations,
out ImmutableArray<string> delegateTypeArgumentsWithNullabilityAnnotations))
{
goto Failure;
}
token.ThrowIfCancellationRequested();
// Check the switch to allow concurrent executions
if (!TryGetAllowConcurrentExecutionsSwitch(
methodSymbol,
attributeData,
commandClassType,
in builder,
out bool allowConcurrentExecutions))
{
goto Failure;
}
token.ThrowIfCancellationRequested();
// Check the switch to control exception flow
if (!TryGetFlowExceptionsToTaskSchedulerSwitch(
methodSymbol,
attributeData,
commandClassType,
in builder,
out bool flowExceptionsToTaskScheduler))
{
goto Failure;
}
token.ThrowIfCancellationRequested();
// Get the CanExecute expression type, if any
if (!TryGetCanExecuteExpressionType(
methodSymbol,
attributeData,
commandTypeArguments,
token,
in builder,
out string? canExecuteMemberName,
out CanExecuteExpressionType? canExecuteExpressionType))
{
goto Failure;
}
token.ThrowIfCancellationRequested();
// Get the option to include a cancel command, if any
if (!TryGetIncludeCancelCommandSwitch(
methodSymbol,
attributeData,
commandClassType,
supportsCancellation,
in builder,
out bool generateCancelCommand))
{
goto Failure;
}
token.ThrowIfCancellationRequested();
// Get all forwarded attributes (don't stop in case of errors, just ignore faulting attributes)
GatherForwardedAttributes(
methodSymbol,
semanticModel,
token,
in builder,
out ImmutableArray<AttributeInfo> fieldAttributes,
out ImmutableArray<AttributeInfo> propertyAttributes);
token.ThrowIfCancellationRequested();
commandInfo = new CommandInfo(
methodSymbol.Name,
fieldName,
propertyName,
commandInterfaceType,
commandClassType,
delegateType,
commandTypeArgumentsWithNullabilityAnnotations,
delegateTypeArgumentsWithNullabilityAnnotations,
canExecuteMemberName,
canExecuteExpressionType,
allowConcurrentExecutions,
flowExceptionsToTaskScheduler,
generateCancelCommand,
fieldAttributes,
propertyAttributes);
diagnostics = builder.ToImmutable();
return true;
Failure:
commandInfo = null;
diagnostics = builder.ToImmutable();
return false;
}
/// <summary>
/// Creates the <see cref="MemberDeclarationSyntax"/> instances for a specified command.
/// </summary>
/// <param name="commandInfo">The input <see cref="CommandInfo"/> instance with the info to generate the command.</param>
/// <returns>The <see cref="MemberDeclarationSyntax"/> instances for the input command.</returns>
public static ImmutableArray<MemberDeclarationSyntax> GetSyntax(CommandInfo commandInfo)
{
// Prepare all necessary type names with type arguments
string commandInterfaceTypeXmlName = commandInfo.CommandTypeArguments.IsEmpty
? commandInfo.CommandInterfaceType
: commandInfo.CommandInterfaceType + "{T}";
string commandClassTypeName = commandInfo.CommandTypeArguments.IsEmpty
? commandInfo.CommandClassType
: $"{commandInfo.CommandClassType}<{string.Join(", ", commandInfo.CommandTypeArguments)}>";
string commandInterfaceTypeName = commandInfo.CommandTypeArguments.IsEmpty
? commandInfo.CommandInterfaceType
: $"{commandInfo.CommandInterfaceType}<{string.Join(", ", commandInfo.CommandTypeArguments)}>";
string delegateTypeName = commandInfo.DelegateTypeArguments.IsEmpty
? commandInfo.DelegateType
: $"{commandInfo.DelegateType}<{string.Join(", ", commandInfo.DelegateTypeArguments)}>";
// Prepare the forwarded field attributes, if any
ImmutableArray<AttributeListSyntax> forwardedFieldAttributes =
commandInfo.ForwardedFieldAttributes
.Select(static a => AttributeList(SingletonSeparatedList(a.GetSyntax())))
.ToImmutableArray();
// Also prepare any forwarded property attributes
ImmutableArray<AttributeListSyntax> forwardedPropertyAttributes =
commandInfo.ForwardedPropertyAttributes
.Select(static a => AttributeList(SingletonSeparatedList(a.GetSyntax())))
.ToImmutableArray();
// Construct the generated field as follows:
//
// /// <summary>The backing field for <see cref="<COMMAND_PROPERTY_NAME>"/></summary>
// [global::System.CodeDom.Compiler.GeneratedCode("...", "...")]
// <FORWARDED_ATTRIBUTES>
// private <COMMAND_TYPE>? <COMMAND_FIELD_NAME>;
FieldDeclarationSyntax fieldDeclaration =
FieldDeclaration(
VariableDeclaration(NullableType(IdentifierName(commandClassTypeName)))
.AddVariables(VariableDeclarator(Identifier(commandInfo.FieldName))))
.AddModifiers(Token(SyntaxKind.PrivateKeyword))
.AddAttributeLists(
AttributeList(SingletonSeparatedList(
Attribute(IdentifierName("global::System.CodeDom.Compiler.GeneratedCode"))
.AddArgumentListArguments(
AttributeArgument(LiteralExpression(SyntaxKind.StringLiteralExpression, Literal(typeof(RelayCommandGenerator).FullName))),
AttributeArgument(LiteralExpression(SyntaxKind.StringLiteralExpression, Literal(typeof(RelayCommandGenerator).Assembly.GetName().Version.ToString()))))))
.WithOpenBracketToken(Token(TriviaList(Comment($"/// <summary>The backing field for <see cref=\"{commandInfo.PropertyName}\"/>.</summary>")), SyntaxKind.OpenBracketToken, TriviaList())))
.AddAttributeLists(forwardedFieldAttributes.ToArray());
// Prepares the argument to pass the underlying method to invoke
using ImmutableArrayBuilder<ArgumentSyntax> commandCreationArguments = ImmutableArrayBuilder<ArgumentSyntax>.Rent();
// The first argument is the execute method, which is always present
commandCreationArguments.Add(
Argument(
ObjectCreationExpression(IdentifierName(delegateTypeName))
.AddArgumentListArguments(Argument(IdentifierName(commandInfo.MethodName)))));
// Get the can execute expression, if available
ExpressionSyntax? canExecuteExpression = commandInfo.CanExecuteExpressionType switch
{
// Create a lambda expression ignoring the input value:
//
// new <RELAY_COMMAND_TYPE>(<METHOD_EXPRESSION>, _ => <CAN_EXECUTE_METHOD>());
CanExecuteExpressionType.MethodInvocationLambdaWithDiscard =>
SimpleLambdaExpression(
Parameter(Identifier(TriviaList(), SyntaxKind.UnderscoreToken, "_", "_", TriviaList())))
.WithExpressionBody(InvocationExpression(IdentifierName(commandInfo.CanExecuteMemberName!))),
// Create a lambda expression returning the property value:
//
// new <RELAY_COMMAND_TYPE>(<METHOD_EXPRESSION>, () => <CAN_EXECUTE_PROPERTY>);
CanExecuteExpressionType.PropertyAccessLambda =>
ParenthesizedLambdaExpression()
.WithExpressionBody(IdentifierName(commandInfo.CanExecuteMemberName!)),
// Create a lambda expression again, but discarding the input value:
//
// new <RELAY_COMMAND_TYPE>(<METHOD_EXPRESSION>, _ => <CAN_EXECUTE_PROPERTY>);
CanExecuteExpressionType.PropertyAccessLambdaWithDiscard =>
SimpleLambdaExpression(
Parameter(Identifier(TriviaList(), SyntaxKind.UnderscoreToken, "_", "_", TriviaList())))
.WithExpressionBody(IdentifierName(commandInfo.CanExecuteMemberName!)),
// Create a method group expression, which will become:
//
// new <RELAY_COMMAND_TYPE>(<METHOD_EXPRESSION>, <CAN_EXECUTE_METHOD>);
CanExecuteExpressionType.MethodGroup => IdentifierName(commandInfo.CanExecuteMemberName!),
_ => null
};
// Add the can execute expression to the arguments, if available
if (canExecuteExpression is not null)
{
commandCreationArguments.Add(Argument(canExecuteExpression));
}
// Enable concurrent executions, if requested
if (commandInfo.AllowConcurrentExecutions && !commandInfo.FlowExceptionsToTaskScheduler)
{
commandCreationArguments.Add(
Argument(MemberAccessExpression(
SyntaxKind.SimpleMemberAccessExpression,
IdentifierName("global::CommunityToolkit.Mvvm.Input.AsyncRelayCommandOptions"),
IdentifierName("AllowConcurrentExecutions"))));
}
else if (commandInfo.FlowExceptionsToTaskScheduler && !commandInfo.AllowConcurrentExecutions)
{
// Enable exception flow, if requested
commandCreationArguments.Add(
Argument(MemberAccessExpression(
SyntaxKind.SimpleMemberAccessExpression,
IdentifierName("global::CommunityToolkit.Mvvm.Input.AsyncRelayCommandOptions"),
IdentifierName("FlowExceptionsToTaskScheduler"))));
}
else if (commandInfo.AllowConcurrentExecutions && commandInfo.FlowExceptionsToTaskScheduler)
{
// Enable both concurrency control and exception flow
commandCreationArguments.Add(
Argument(BinaryExpression(
SyntaxKind.BitwiseOrExpression,
MemberAccessExpression(
SyntaxKind.SimpleMemberAccessExpression,
IdentifierName("global::CommunityToolkit.Mvvm.Input.AsyncRelayCommandOptions"),
IdentifierName("AllowConcurrentExecutions")),
MemberAccessExpression(
SyntaxKind.SimpleMemberAccessExpression,
IdentifierName("global::CommunityToolkit.Mvvm.Input.AsyncRelayCommandOptions"),
IdentifierName("FlowExceptionsToTaskScheduler")))));
}
// Construct the generated property as follows (the explicit delegate cast is needed to avoid overload resolution conflicts):
//
// /// <summary>Gets an <see cref="<COMMAND_INTERFACE_TYPE>" instance wrapping <see cref="<METHOD_NAME>"/> and <see cref="<OPTIONAL_CAN_EXECUTE>"/>.</summary>
// [global::System.CodeDom.Compiler.GeneratedCode("...", "...")]
// [global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
// <FORWARDED_ATTRIBUTES>
// public <COMMAND_TYPE> <COMMAND_PROPERTY_NAME> => <COMMAND_FIELD_NAME> ??= new <RELAY_COMMAND_TYPE>(<COMMAND_CREATION_ARGUMENTS>);
PropertyDeclarationSyntax propertyDeclaration =
PropertyDeclaration(
IdentifierName(commandInterfaceTypeName),
Identifier(commandInfo.PropertyName))
.AddModifiers(Token(SyntaxKind.PublicKeyword))
.AddAttributeLists(
AttributeList(SingletonSeparatedList(
Attribute(IdentifierName("global::System.CodeDom.Compiler.GeneratedCode"))
.AddArgumentListArguments(
AttributeArgument(LiteralExpression(SyntaxKind.StringLiteralExpression, Literal(typeof(RelayCommandGenerator).FullName))),
AttributeArgument(LiteralExpression(SyntaxKind.StringLiteralExpression, Literal(typeof(RelayCommandGenerator).Assembly.GetName().Version.ToString()))))))
.WithOpenBracketToken(Token(TriviaList(Comment(
$"/// <summary>Gets an <see cref=\"{commandInterfaceTypeXmlName}\"/> instance wrapping <see cref=\"{commandInfo.MethodName}\"/>.</summary>")),
SyntaxKind.OpenBracketToken,
TriviaList())),
AttributeList(SingletonSeparatedList(Attribute(IdentifierName("global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage")))))
.AddAttributeLists(forwardedPropertyAttributes.ToArray())
.WithExpressionBody(
ArrowExpressionClause(
AssignmentExpression(
SyntaxKind.CoalesceAssignmentExpression,
IdentifierName(commandInfo.FieldName),
ObjectCreationExpression(IdentifierName(commandClassTypeName))
.AddArgumentListArguments(commandCreationArguments.ToArray()))))
.WithSemicolonToken(Token(SyntaxKind.SemicolonToken));
// Conditionally declare the additional members for the cancel commands
if (commandInfo.IncludeCancelCommand)
{
// Prepare all necessary member and type names
string cancelCommandFieldName = $"{commandInfo.FieldName.Substring(0, commandInfo.FieldName.Length - "Command".Length)}CancelCommand";
string cancelCommandPropertyName = $"{commandInfo.PropertyName.Substring(0, commandInfo.PropertyName.Length - "Command".Length)}CancelCommand";
// Construct the generated field for the cancel command as follows:
//
// /// <summary>The backing field for <see cref="<COMMAND_PROPERTY_NAME>"/></summary>
// [global::System.CodeDom.Compiler.GeneratedCode("...", "...")]
// private global::System.Windows.Input.ICommand? <CANCEL_COMMAND_FIELD_NAME>;
FieldDeclarationSyntax cancelCommandFieldDeclaration =
FieldDeclaration(
VariableDeclaration(NullableType(IdentifierName("global::System.Windows.Input.ICommand")))
.AddVariables(VariableDeclarator(Identifier(cancelCommandFieldName))))
.AddModifiers(Token(SyntaxKind.PrivateKeyword))
.AddAttributeLists(
AttributeList(SingletonSeparatedList(
Attribute(IdentifierName("global::System.CodeDom.Compiler.GeneratedCode"))
.AddArgumentListArguments(
AttributeArgument(LiteralExpression(SyntaxKind.StringLiteralExpression, Literal(typeof(RelayCommandGenerator).FullName))),
AttributeArgument(LiteralExpression(SyntaxKind.StringLiteralExpression, Literal(typeof(RelayCommandGenerator).Assembly.GetName().Version.ToString()))))))
.WithOpenBracketToken(Token(TriviaList(Comment($"/// <summary>The backing field for <see cref=\"{cancelCommandPropertyName}\"/>.</summary>")), SyntaxKind.OpenBracketToken, TriviaList())));
// Construct the generated property as follows (the explicit delegate cast is needed to avoid overload resolution conflicts):
//
// /// <summary>Gets an <see cref="global::System.Windows.Input.ICommand" instance that can be used to cancel <see cref="<COMMAND_PROPERTY_NAME>"/>.</summary>
// [global::System.CodeDom.Compiler.GeneratedCode("...", "...")]
// [global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
// public global::System.Windows.Input.ICommand <CANCEL_COMMAND_PROPERTY_NAME> => <CANCEL_COMMAND_FIELD_NAME> ??= global::CommunityToolkit.Mvvm.Input.IAsyncRelayCommandExtensions.CreateCancelCommand(<COMMAND_PROPERTY_NAME>);
PropertyDeclarationSyntax cancelCommandPropertyDeclaration =
PropertyDeclaration(
IdentifierName("global::System.Windows.Input.ICommand"),
Identifier(cancelCommandPropertyName))
.AddModifiers(Token(SyntaxKind.PublicKeyword))
.AddAttributeLists(
AttributeList(SingletonSeparatedList(
Attribute(IdentifierName("global::System.CodeDom.Compiler.GeneratedCode"))
.AddArgumentListArguments(
AttributeArgument(LiteralExpression(SyntaxKind.StringLiteralExpression, Literal(typeof(RelayCommandGenerator).FullName))),
AttributeArgument(LiteralExpression(SyntaxKind.StringLiteralExpression, Literal(typeof(RelayCommandGenerator).Assembly.GetName().Version.ToString()))))))
.WithOpenBracketToken(Token(TriviaList(Comment(
$"/// <summary>Gets an <see cref=\"global::System.Windows.Input.ICommand\"/> instance that can be used to cancel <see cref=\"{commandInfo.PropertyName}\"/>.</summary>")),
SyntaxKind.OpenBracketToken,
TriviaList())),
AttributeList(SingletonSeparatedList(Attribute(IdentifierName("global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage")))))
.WithExpressionBody(
ArrowExpressionClause(
AssignmentExpression(
SyntaxKind.CoalesceAssignmentExpression,
IdentifierName(cancelCommandFieldName),
InvocationExpression(
MemberAccessExpression(
SyntaxKind.SimpleMemberAccessExpression,
IdentifierName("global::CommunityToolkit.Mvvm.Input.IAsyncRelayCommandExtensions"),
IdentifierName("CreateCancelCommand")))
.AddArgumentListArguments(Argument(IdentifierName(commandInfo.PropertyName))))))
.WithSemicolonToken(Token(SyntaxKind.SemicolonToken));
return ImmutableArray.Create<MemberDeclarationSyntax>(fieldDeclaration, propertyDeclaration, cancelCommandFieldDeclaration, cancelCommandPropertyDeclaration);
}
return ImmutableArray.Create<MemberDeclarationSyntax>(fieldDeclaration, propertyDeclaration);
}
/// <summary>
/// Validates that a target method used as source for a command is unique within its containing type.
/// </summary>
/// <param name="methodSymbol">The input <see cref="IMethodSymbol"/> instance to process.</param>
/// <param name="diagnostics">The current collection of gathered diagnostics.</param>
/// <returns>Whether or not <paramref name="methodSymbol"/> was unique within its containing type.</returns>
private static bool IsCommandDefinitionUnique(IMethodSymbol methodSymbol, in ImmutableArrayBuilder<DiagnosticInfo> diagnostics)
{
// If a duplicate is present in any of the base types, always emit a diagnostic for the current method.
// That is, there is no need to check the order: we assume the priority is top-down in the type hierarchy.
// This check has to be done first, as otherwise there would always be a false positive for the current type.
foreach (ISymbol symbol in methodSymbol.ContainingType.BaseType?.GetAllMembers(methodSymbol.Name) ?? Enumerable.Empty<ISymbol>())
{
if (symbol is IMethodSymbol otherSymbol &&
otherSymbol.HasAttributeWithFullyQualifiedMetadataName("CommunityToolkit.Mvvm.Input.RelayCommandAttribute"))
{
diagnostics.Add(
MultipleRelayCommandMethodOverloadsError,
methodSymbol,
methodSymbol.ContainingType,
methodSymbol);
return false;
}
}
// Check for duplicates in the containing type for the annotated method
foreach (ISymbol symbol in methodSymbol.ContainingType.GetMembers(methodSymbol.Name))
{
if (symbol is IMethodSymbol otherSymbol &&
otherSymbol.HasAttributeWithFullyQualifiedMetadataName("CommunityToolkit.Mvvm.Input.RelayCommandAttribute"))
{
// If the first [RelayCommand] overload is the current symbol, return immediately. This makes it so
// that if multiple overloads are present, only the ones after the first declared one will have
// diagnostics generated for them, while the first one will remain valid and will keep working.
if (SymbolEqualityComparer.Default.Equals(methodSymbol, otherSymbol))
{
return true;
}
// If the two method symbols are partial and either is the implementation of the other one, this is allowed
if ((methodSymbol is { IsPartialDefinition: true, PartialImplementationPart: { } partialImplementation } &&
SymbolEqualityComparer.Default.Equals(otherSymbol, partialImplementation)) ||
(otherSymbol is { IsPartialDefinition: true, PartialImplementationPart: { } otherPartialImplementation } &&
SymbolEqualityComparer.Default.Equals(methodSymbol, otherPartialImplementation)))
{
continue;
}
diagnostics.Add(
MultipleRelayCommandMethodOverloadsError,
methodSymbol,
methodSymbol.ContainingType,
methodSymbol);
return false;
}
}
return true;
}
/// <summary>
/// Get the generated field and property names for the input method.
/// </summary>
/// <param name="methodSymbol">The input <see cref="IMethodSymbol"/> instance to process.</param>
/// <returns>The generated field and property names for <paramref name="methodSymbol"/>.</returns>
public static (string FieldName, string PropertyName) GetGeneratedFieldAndPropertyNames(IMethodSymbol methodSymbol)
{
string propertyName = methodSymbol.Name;
// Strip the "On" prefix, if present. Only do this if the name is longer than 2 characters,
// and if the 3rd character is not a lowercase letter. This is needed to avoid accidentally
// stripping fales positives for "On" prefixes in names such as "Onboard".
if (propertyName.Length > 2 &&
propertyName.StartsWith("On") &&
!char.IsLower(propertyName[2]))
{
propertyName = propertyName.Substring(2);
}
// Strip the "Async" suffix for methods returning a Task type
if (methodSymbol.Name.EndsWith("Async") &&
methodSymbol.ReturnType.HasOrInheritsFromFullyQualifiedMetadataName("System.Threading.Tasks.Task"))
{
propertyName = propertyName.Substring(0, propertyName.Length - "Async".Length);
}
propertyName += "Command";
char firstCharacter = propertyName[0];
char loweredFirstCharacter = char.ToLower(firstCharacter, CultureInfo.InvariantCulture);
// The field name is generated depending on whether the first character can be lowered:
// - If it can, then the field name is just the property name starting in lowercase.
// - If it can't (eg. starts with '中'), then the '_' prefix is added to the property name.
string fieldName = (firstCharacter == loweredFirstCharacter) switch
{
true => $"_{propertyName}",
false => $"{loweredFirstCharacter}{propertyName.Substring(1)}"
};
return (fieldName, propertyName);
}
/// <summary>
/// Gets the type symbols for the input method, if supported.
/// </summary>
/// <param name="methodSymbol">The input <see cref="IMethodSymbol"/> instance to process.</param>
/// <param name="diagnostics">The current collection of gathered diagnostics.</param>
/// <param name="commandInterfaceType">The command interface type name.</param>
/// <param name="commandClassType">The command class type name.</param>
/// <param name="delegateType">The delegate type name for the wrapped method.</param>
/// <param name="supportsCancellation">Indicates whether or not the resulting command supports cancellation.</param>
/// <param name="commandTypeArguments">The type arguments for <paramref name="commandInterfaceType"/> and <paramref name="commandClassType"/>, if any.</param>
/// <param name="commandTypeArgumentsWithNullabilityAnnotations">Same as <paramref name="commandTypeArguments"/>, but with nullability annotations.</param>
/// <param name="delegateTypeArgumentsWithNullabilityAnnotations">The type arguments for <paramref name="delegateType"/>, if any, with nullability annotations.</param>
/// <returns>Whether or not <paramref name="methodSymbol"/> was valid and the requested types have been set.</returns>
private static bool TryMapCommandTypesFromMethod(
IMethodSymbol methodSymbol,
in ImmutableArrayBuilder<DiagnosticInfo> diagnostics,
[NotNullWhen(true)] out string? commandInterfaceType,
[NotNullWhen(true)] out string? commandClassType,
[NotNullWhen(true)] out string? delegateType,
out bool supportsCancellation,
out ImmutableArray<string> commandTypeArguments,
out ImmutableArray<string> commandTypeArgumentsWithNullabilityAnnotations,
out ImmutableArray<string> delegateTypeArgumentsWithNullabilityAnnotations)
{
// Map <void, void> to IRelayCommand, RelayCommand, Action
if (methodSymbol.ReturnsVoid && methodSymbol.Parameters.Length == 0)
{
commandInterfaceType = "global::CommunityToolkit.Mvvm.Input.IRelayCommand";
commandClassType = "global::CommunityToolkit.Mvvm.Input.RelayCommand";
delegateType = "global::System.Action";
supportsCancellation = false;
commandTypeArguments = ImmutableArray<string>.Empty;
commandTypeArgumentsWithNullabilityAnnotations = ImmutableArray<string>.Empty;
delegateTypeArgumentsWithNullabilityAnnotations = ImmutableArray<string>.Empty;
return true;
}
// Map <T, void> to IRelayCommand<T>, RelayCommand<T>, Action<T>
if (methodSymbol.ReturnsVoid &&
methodSymbol.Parameters.Length == 1 &&
methodSymbol.Parameters[0] is IParameterSymbol { RefKind: RefKind.None, Type: { IsRefLikeType: false, TypeKind: not TypeKind.Pointer and not TypeKind.FunctionPointer } } parameter)
{
commandInterfaceType = "global::CommunityToolkit.Mvvm.Input.IRelayCommand";
commandClassType = "global::CommunityToolkit.Mvvm.Input.RelayCommand";
delegateType = "global::System.Action";
supportsCancellation = false;
commandTypeArguments = ImmutableArray.Create(parameter.Type.GetFullyQualifiedName());
commandTypeArgumentsWithNullabilityAnnotations = ImmutableArray.Create(parameter.Type.GetFullyQualifiedNameWithNullabilityAnnotations());
delegateTypeArgumentsWithNullabilityAnnotations = ImmutableArray.Create(parameter.Type.GetFullyQualifiedNameWithNullabilityAnnotations());
return true;
}
// Map all Task-returning methods
if (methodSymbol.ReturnType.HasOrInheritsFromFullyQualifiedMetadataName("System.Threading.Tasks.Task"))
{
// Map <void, Task> to IAsyncRelayCommand, AsyncRelayCommand, Func<Task>
if (methodSymbol.Parameters.Length == 0)
{
commandInterfaceType = "global::CommunityToolkit.Mvvm.Input.IAsyncRelayCommand";
commandClassType = "global::CommunityToolkit.Mvvm.Input.AsyncRelayCommand";
delegateType = "global::System.Func";
supportsCancellation = false;
commandTypeArguments = ImmutableArray<string>.Empty;
commandTypeArgumentsWithNullabilityAnnotations = ImmutableArray<string>.Empty;
delegateTypeArgumentsWithNullabilityAnnotations = ImmutableArray.Create("global::System.Threading.Tasks.Task");
return true;
}
if (methodSymbol.Parameters.Length == 1 &&
methodSymbol.Parameters[0] is IParameterSymbol { RefKind: RefKind.None, Type: { IsRefLikeType: false, TypeKind: not TypeKind.Pointer and not TypeKind.FunctionPointer } } singleParameter)
{
// Map <CancellationToken, Task> to IAsyncRelayCommand, AsyncRelayCommand, Func<CancellationToken, Task>
if (singleParameter.Type.HasFullyQualifiedMetadataName("System.Threading.CancellationToken"))
{
commandInterfaceType = "global::CommunityToolkit.Mvvm.Input.IAsyncRelayCommand";
commandClassType = "global::CommunityToolkit.Mvvm.Input.AsyncRelayCommand";
delegateType = "global::System.Func";
supportsCancellation = true;
commandTypeArguments = ImmutableArray<string>.Empty;
commandTypeArgumentsWithNullabilityAnnotations = ImmutableArray<string>.Empty;
delegateTypeArgumentsWithNullabilityAnnotations = ImmutableArray.Create("global::System.Threading.CancellationToken", "global::System.Threading.Tasks.Task");
return true;
}
// Map <T, Task> to IAsyncRelayCommand<T>, AsyncRelayCommand<T>, Func<T, Task>
commandInterfaceType = "global::CommunityToolkit.Mvvm.Input.IAsyncRelayCommand";
commandClassType = "global::CommunityToolkit.Mvvm.Input.AsyncRelayCommand";
delegateType = "global::System.Func";
supportsCancellation = false;
commandTypeArguments = ImmutableArray.Create(singleParameter.Type.GetFullyQualifiedName());
commandTypeArgumentsWithNullabilityAnnotations = ImmutableArray.Create(singleParameter.Type.GetFullyQualifiedNameWithNullabilityAnnotations());
delegateTypeArgumentsWithNullabilityAnnotations = ImmutableArray.Create(singleParameter.Type.GetFullyQualifiedNameWithNullabilityAnnotations(), "global::System.Threading.Tasks.Task");
return true;
}
// Map <T, CancellationToken, Task> to IAsyncRelayCommand<T>, AsyncRelayCommand<T>, Func<T, CancellationToken, Task>
if (methodSymbol.Parameters.Length == 2 &&
methodSymbol.Parameters[0] is IParameterSymbol { RefKind: RefKind.None, Type: { IsRefLikeType: false, TypeKind: not TypeKind.Pointer and not TypeKind.FunctionPointer } } firstParameter &&
methodSymbol.Parameters[1] is IParameterSymbol { RefKind: RefKind.None, Type: { IsRefLikeType: false, TypeKind: not TypeKind.Pointer and not TypeKind.FunctionPointer } } secondParameter &&
secondParameter.Type.HasFullyQualifiedMetadataName("System.Threading.CancellationToken"))
{
commandInterfaceType = "global::CommunityToolkit.Mvvm.Input.IAsyncRelayCommand";
commandClassType = "global::CommunityToolkit.Mvvm.Input.AsyncRelayCommand";
delegateType = "global::System.Func";
supportsCancellation = true;
commandTypeArguments = ImmutableArray.Create(firstParameter.Type.GetFullyQualifiedName());
commandTypeArgumentsWithNullabilityAnnotations = ImmutableArray.Create(firstParameter.Type.GetFullyQualifiedNameWithNullabilityAnnotations());
delegateTypeArgumentsWithNullabilityAnnotations = ImmutableArray.Create(firstParameter.Type.GetFullyQualifiedNameWithNullabilityAnnotations(), "global::System.Threading.CancellationToken", "global::System.Threading.Tasks.Task");
return true;
}
}
diagnostics.Add(InvalidRelayCommandMethodSignatureError, methodSymbol, methodSymbol.ContainingType, methodSymbol);
commandInterfaceType = null;
commandClassType = null;
delegateType = null;
supportsCancellation = false;
commandTypeArguments = ImmutableArray<string>.Empty;
commandTypeArgumentsWithNullabilityAnnotations = ImmutableArray<string>.Empty;
delegateTypeArgumentsWithNullabilityAnnotations = ImmutableArray<string>.Empty;
return false;
}
/// <summary>
/// Checks whether or not the user has requested to configure the handling of concurrent executions.
/// </summary>
/// <param name="methodSymbol">The input <see cref="IMethodSymbol"/> instance to process.</param>
/// <param name="attributeData">The <see cref="AttributeData"/> instance the method was annotated with.</param>
/// <param name="commandClassType">The command class type name.</param>
/// <param name="diagnostics">The current collection of gathered diagnostics.</param>
/// <param name="allowConcurrentExecutions">Whether or not concurrent executions have been enabled.</param>
/// <returns>Whether or not a value for <paramref name="allowConcurrentExecutions"/> could be retrieved successfully.</returns>
private static bool TryGetAllowConcurrentExecutionsSwitch(
IMethodSymbol methodSymbol,
AttributeData attributeData,
string commandClassType,
in ImmutableArrayBuilder<DiagnosticInfo> diagnostics,
out bool allowConcurrentExecutions)
{
// Try to get the custom switch for concurrent executions (the default is false)
if (!attributeData.TryGetNamedArgument("AllowConcurrentExecutions", out allowConcurrentExecutions))
{
allowConcurrentExecutions = false;
return true;
}
// If the current type is an async command type and concurrent execution is disabled, pass that value to the constructor.
// If concurrent executions are allowed, there is no need to add any additional argument, as that is the default value.
if (commandClassType is "global::CommunityToolkit.Mvvm.Input.AsyncRelayCommand")
{
return true;
}
else
{
diagnostics.Add(InvalidConcurrentExecutionsParameterError, methodSymbol, methodSymbol.ContainingType, methodSymbol);
return false;
}
}
/// <summary>
/// Checks whether or not the user has requested to configure the task scheduler exception flow option.
/// </summary>
/// <param name="methodSymbol">The input <see cref="IMethodSymbol"/> instance to process.</param>
/// <param name="attributeData">The <see cref="AttributeData"/> instance the method was annotated with.</param>
/// <param name="commandClassType">The command class type name.</param>
/// <param name="diagnostics">The current collection of gathered diagnostics.</param>
/// <param name="flowExceptionsToTaskScheduler">Whether or not task scheduler exception flow have been enabled.</param>
/// <returns>Whether or not a value for <paramref name="flowExceptionsToTaskScheduler"/> could be retrieved successfully.</returns>
private static bool TryGetFlowExceptionsToTaskSchedulerSwitch(
IMethodSymbol methodSymbol,
AttributeData attributeData,
string commandClassType,
in ImmutableArrayBuilder<DiagnosticInfo> diagnostics,
out bool flowExceptionsToTaskScheduler)
{
// Try to get the custom switch for task scheduler exception flow (the default is false)
if (!attributeData.TryGetNamedArgument("FlowExceptionsToTaskScheduler", out flowExceptionsToTaskScheduler))
{
flowExceptionsToTaskScheduler = false;
return true;
}
// Just like with the concurrency control option, check that the target command type is asynchronous
if (commandClassType is "global::CommunityToolkit.Mvvm.Input.AsyncRelayCommand")
{
return true;
}
else
{
diagnostics.Add(InvalidFlowExceptionsToTaskSchedulerParameterError, methodSymbol, methodSymbol.ContainingType, methodSymbol);
return false;
}
}
/// <summary>
/// Checks whether or not the user has requested to also generate a cancel command.
/// </summary>
/// <param name="methodSymbol">The input <see cref="IMethodSymbol"/> instance to process.</param>
/// <param name="attributeData">The <see cref="AttributeData"/> instance the method was annotated with.</param>
/// <param name="commandClassType">The command class type name.</param>
/// <param name="supportsCancellation">Indicates whether or not the command supports cancellation.</param>
/// <param name="diagnostics">The current collection of gathered diagnostics.</param>
/// <param name="generateCancelCommand">Whether or not concurrent executions have been enabled.</param>
/// <returns>Whether or not a value for <paramref name="generateCancelCommand"/> could be retrieved successfully.</returns>
private static bool TryGetIncludeCancelCommandSwitch(
IMethodSymbol methodSymbol,
AttributeData attributeData,
string commandClassType,
bool supportsCancellation,
in ImmutableArrayBuilder<DiagnosticInfo> diagnostics,
out bool generateCancelCommand)
{
// Try to get the custom switch for cancel command generation (the default is false)
if (!attributeData.TryGetNamedArgument("IncludeCancelCommand", out generateCancelCommand))
{
generateCancelCommand = false;
return true;
}
// If the current type is an async command type and cancellation is supported, pass that value to the constructor.
// Otherwise, the current attribute use is not valid, so a diagnostic message should be produced.
if (commandClassType is "global::CommunityToolkit.Mvvm.Input.AsyncRelayCommand" &&
supportsCancellation)
{
return true;
}
else
{
diagnostics.Add(InvalidIncludeCancelCommandParameterError, methodSymbol, methodSymbol.ContainingType, methodSymbol);
return false;
}
}
/// <summary>
/// Tries to get the expression type for the "CanExecute" property, if available.
/// </summary>
/// <param name="methodSymbol">The input <see cref="IMethodSymbol"/> instance to process.</param>
/// <param name="attributeData">The <see cref="AttributeData"/> instance for <paramref name="methodSymbol"/>.</param>
/// <param name="commandTypeArguments">The command type arguments, if any.</param>
/// <param name="token">The cancellation token for the current operation.</param>
/// <param name="diagnostics">The current collection of gathered diagnostics.</param>
/// <param name="canExecuteMemberName">The resulting can execute member name, if available.</param>
/// <param name="canExecuteExpressionType">The resulting expression type, if available.</param>
/// <returns>Whether or not a value for <paramref name="canExecuteMemberName"/> and <paramref name="canExecuteExpressionType"/> could be determined (may include <see langword="null"/>).</returns>
private static bool TryGetCanExecuteExpressionType(
IMethodSymbol methodSymbol,
AttributeData attributeData,
ImmutableArray<string> commandTypeArguments,
CancellationToken token,
in ImmutableArrayBuilder<DiagnosticInfo> diagnostics,
out string? canExecuteMemberName,
out CanExecuteExpressionType? canExecuteExpressionType)
{
// Get the can execute member, if any
if (!attributeData.TryGetNamedArgument("CanExecute", out string? memberName))
{
canExecuteMemberName = null;
canExecuteExpressionType = null;
return true;
}
if (memberName is null)
{
diagnostics.Add(InvalidCanExecuteMemberNameError, methodSymbol, memberName ?? string.Empty, methodSymbol.ContainingType);
goto Failure;
}
ImmutableArray<ISymbol> canExecuteSymbols = methodSymbol.ContainingType!.GetAllMembers(memberName).ToImmutableArray();
if (canExecuteSymbols.IsEmpty)
{
// Special case for when the target member is a generated property from [ObservableProperty]
if (TryGetCanExecuteMemberFromGeneratedProperty(memberName, methodSymbol.ContainingType, commandTypeArguments, token, out canExecuteExpressionType))
{
canExecuteMemberName = memberName;
return true;
}
diagnostics.Add(InvalidCanExecuteMemberNameError, methodSymbol, memberName, methodSymbol.ContainingType);
}
else if (canExecuteSymbols.Length > 1)
{
diagnostics.Add(MultipleCanExecuteMemberNameMatchesError, methodSymbol, memberName, methodSymbol.ContainingType);
}
else if (TryGetCanExecuteExpressionFromSymbol(canExecuteSymbols[0], commandTypeArguments, out canExecuteExpressionType))
{
canExecuteMemberName = memberName;
return true;
}
else
{
diagnostics.Add(InvalidCanExecuteMemberError, methodSymbol, memberName, methodSymbol.ContainingType);
}
Failure:
canExecuteMemberName = null;
canExecuteExpressionType = null;
return false;
}
/// <summary>
/// Gets the expression type for the can execute logic, if possible.
/// </summary>
/// <param name="canExecuteSymbol">The can execute member symbol (either a method or a property).</param>
/// <param name="commandTypeArguments">The type arguments for the command interface, if any.</param>
/// <param name="canExecuteExpressionType">The resulting can execute expression type, if available.</param>
/// <returns>Whether or not <paramref name="canExecuteExpressionType"/> was set and the input symbol was valid.</returns>
private static bool TryGetCanExecuteExpressionFromSymbol(
ISymbol canExecuteSymbol,
ImmutableArray<string> commandTypeArguments,
[NotNullWhen(true)] out CanExecuteExpressionType? canExecuteExpressionType)
{
if (canExecuteSymbol is IMethodSymbol canExecuteMethodSymbol)
{
// The return type must always be a bool
if (canExecuteMethodSymbol.ReturnType is not { SpecialType: SpecialType.System_Boolean })
{
goto Failure;
}
// Parameterless methods are always valid
if (canExecuteMethodSymbol.Parameters.IsEmpty)
{
// If the command is generic, the input value is ignored
if (commandTypeArguments.Length > 0)
{
canExecuteExpressionType = CanExecuteExpressionType.MethodInvocationLambdaWithDiscard;
}
else
{
canExecuteExpressionType = CanExecuteExpressionType.MethodGroup;
}
return true;
}
// If the method has parameters, it has to have a single one matching the command type
if (canExecuteMethodSymbol.Parameters.Length == 1 &&
commandTypeArguments.Length == 1 &&
canExecuteMethodSymbol.Parameters[0].Type.HasFullyQualifiedName(commandTypeArguments[0]))
{
// Create a method group expression again
canExecuteExpressionType = CanExecuteExpressionType.MethodGroup;
return true;
}
}
else if (canExecuteSymbol is IPropertySymbol { GetMethod: not null } canExecutePropertySymbol)
{
// The property type must always be a bool
if (canExecutePropertySymbol.Type is not { SpecialType: SpecialType.System_Boolean })
{
goto Failure;
}
if (commandTypeArguments.Length > 0)
{
canExecuteExpressionType = CanExecuteExpressionType.PropertyAccessLambdaWithDiscard;
}
else
{
canExecuteExpressionType = CanExecuteExpressionType.PropertyAccessLambda;
}
return true;
}
Failure:
canExecuteExpressionType = null;
return false;
}
/// <summary>
/// Gets the expression type for the can execute logic, if possible.
/// </summary>
/// <param name="memberName">The member name passed to <c>[RelayCommand(CanExecute = ...)]</c>.</param>
/// <param name="containingType">The containing type for the method annotated with <c>[RelayCommand]</c>.</param>
/// <param name="commandTypeArguments">The type arguments for the command interface, if any.</param>
/// <param name="token">The cancellation token for the current operation.</param>
/// <param name="canExecuteExpressionType">The resulting can execute expression type, if available.</param>
/// <returns>Whether or not <paramref name="canExecuteExpressionType"/> was set and the input symbol was valid.</returns>
private static bool TryGetCanExecuteMemberFromGeneratedProperty(
string memberName,
INamedTypeSymbol containingType,
ImmutableArray<string> commandTypeArguments,
CancellationToken token,
[NotNullWhen(true)] out CanExecuteExpressionType? canExecuteExpressionType)
{
foreach (ISymbol memberSymbol in containingType.GetAllMembers())
{
// Only look for instance fields of bool type
if (memberSymbol is not IFieldSymbol { IsStatic: false, Type.SpecialType: SpecialType.System_Boolean } fieldSymbol)
{
continue;
}
token.ThrowIfCancellationRequested();
ImmutableArray<AttributeData> attributes = memberSymbol.GetAttributes();
// Only filter fields with the [ObservableProperty] attribute
if (memberSymbol is IFieldSymbol &&
!attributes.Any(static a => a.AttributeClass?.HasFullyQualifiedMetadataName(
"CommunityToolkit.Mvvm.ComponentModel.ObservablePropertyAttribute") == true))
{
continue;
}
// Get the target property name either directly or matching the generated one
string propertyName = ObservablePropertyGenerator.Execute.GetGeneratedPropertyName(fieldSymbol);
// If the generated property name matches, get the right expression type
if (memberName == propertyName)
{
if (commandTypeArguments.Length > 0)
{
canExecuteExpressionType = CanExecuteExpressionType.PropertyAccessLambdaWithDiscard;
}
else
{
canExecuteExpressionType = CanExecuteExpressionType.PropertyAccessLambda;
}
return true;
}
}
canExecuteExpressionType = null;
return false;
}
/// <summary>
/// Gathers all forwarded attributes for the generated field and property.
/// </summary>
/// <param name="methodSymbol">The input <see cref="IMethodSymbol"/> instance to process.</param>
/// <param name="semanticModel">The <see cref="SemanticModel"/> instance for the current run.</param>
/// <param name="token">The cancellation token for the current operation.</param>
/// <param name="diagnostics">The current collection of gathered diagnostics.</param>
/// <param name="fieldAttributes">The resulting field attributes to forward.</param>
/// <param name="propertyAttributes">The resulting property attributes to forward.</param>
private static void GatherForwardedAttributes(
IMethodSymbol methodSymbol,
SemanticModel semanticModel,
CancellationToken token,
in ImmutableArrayBuilder<DiagnosticInfo> diagnostics,
out ImmutableArray<AttributeInfo> fieldAttributes,
out ImmutableArray<AttributeInfo> propertyAttributes)
{
using ImmutableArrayBuilder<AttributeInfo> fieldAttributesInfo = ImmutableArrayBuilder<AttributeInfo>.Rent();
using ImmutableArrayBuilder<AttributeInfo> propertyAttributesInfo = ImmutableArrayBuilder<AttributeInfo>.Rent();
static void GatherForwardedAttributes(
IMethodSymbol methodSymbol,
SemanticModel semanticModel,
CancellationToken token,
in ImmutableArrayBuilder<DiagnosticInfo> diagnostics,
in ImmutableArrayBuilder<AttributeInfo> fieldAttributesInfo,
in ImmutableArrayBuilder<AttributeInfo> propertyAttributesInfo)
{
// Get the single syntax reference for the input method symbol (there should be only one)
if (methodSymbol.DeclaringSyntaxReferences is not [SyntaxReference syntaxReference])
{
return;
}