Files
Terminal.Gui/Analyzers/Terminal.Gui.Analyzers.Internal/Generators/EnumExtensions/CodeWriter.cs

236 lines
11 KiB
C#

using System;
using System.CodeDom.Compiler;
using System.Diagnostics.CodeAnalysis;
using System.IO;
using System.Text;
using Microsoft.CodeAnalysis.Text;
using Terminal.Gui.Analyzers.Internal.Constants;
namespace Terminal.Gui.Analyzers.Internal.Generators.EnumExtensions;
/// <summary>
/// The class responsible for turning an <see cref="EnumExtensionMethodsGenerationInfo"/>
/// into actual C# code.
/// </summary>
/// <remarks>Try to use this type as infrequently as possible.</remarks>
/// <param name="metadata">
/// A reference to an <see cref="IGeneratedTypeMetadata{TSelf}"/> which will be used
/// to generate the extension class code. The object will not be validated,
/// so it is critical that it be correct and remain unchanged while in use
/// by an instance of this class. Behavior if those rules are not followed
/// is undefined.
/// </param>
[SuppressMessage ("CodeQuality", "IDE0079", Justification = "Suppressions here are intentional and the warnings they disable are just noise.")]
internal sealed class CodeWriter (in EnumExtensionMethodsGenerationInfo metadata) : IStandardCSharpCodeGenerator<EnumExtensionMethodsGenerationInfo>
{
// Using the null suppression operator here because this will always be
// initialized to non-null before a reference to it is returned.
private SourceText _sourceText = null!;
/// <inheritdoc/>
public EnumExtensionMethodsGenerationInfo Metadata
{
[MethodImpl (MethodImplOptions.AggressiveInlining)]
[return: NotNull]
get;
[param: DisallowNull]
set;
} = metadata;
/// <inheritdoc/>
public ref readonly SourceText GenerateSourceText (Encoding? encoding = null)
{
encoding ??= Encoding.UTF8;
_sourceText = SourceText.From (GetFullSourceText (), encoding);
return ref _sourceText;
}
/// <summary>
/// Gets the using directive for the namespace containing the enum,
/// if different from the extension class namespace, or an empty string, if they are the same.
/// </summary>
private string EnumNamespaceUsingDirective => Metadata.TargetTypeNamespace != Metadata.GeneratedTypeNamespace
// ReSharper disable once HeapView.ObjectAllocation
? $"using {Metadata.TargetTypeNamespace};"
: string.Empty;
private string EnumTypeKeyword => Metadata.EnumBackingTypeCode switch
{
TypeCode.Int32 => "int",
TypeCode.UInt32 => "uint",
_ => string.Empty
};
/// <summary>Gets the class declaration line.</summary>
private string ExtensionClassDeclarationLine => $"public static partial class {Metadata.GeneratedTypeName}";
// ReSharper disable once HeapView.ObjectAllocation
/// <summary>Gets the XmlDoc for the extension class declaration.</summary>
private string ExtensionClassDeclarationXmlDoc =>
$"/// <summary>Extension methods for the <see cref=\"{Metadata.TargetTypeFullName}\"/> <see langword=\"enum\" /> type.</summary>";
// ReSharper disable once HeapView.ObjectAllocation
/// <summary>Gets the extension class file-scoped namespace directive.</summary>
private string ExtensionClassNamespaceDirective => $"namespace {Metadata.GeneratedTypeNamespace};";
/// <summary>
/// An attribute to decorate the extension class with for easy mapping back to the target enum type, for reflection and
/// analysis.
/// </summary>
private string ExtensionsForTypeAttributeLine => $"[ExtensionsForEnumType<{Metadata.TargetTypeFullName}>]";
/// <summary>
/// Creates the code for the FastHasFlags method.
/// </summary>
/// <remarks>
/// Since the generator already only writes code for enums backed by <see langword="int"/> and <see langword="uint"/>,
/// this method is safe, as we'll always be using a DWORD.
/// </remarks>
/// <param name="w">An instance of an <see cref="IndentedTextWriter"/> to write to.</param>
private void GetFastHasFlagsMethods (IndentedTextWriter w)
{
// The version taking the same enum type as the check value.
w.WriteLine (
$"/// <summary>Determines if the specified flags are set in the current value of this <see cref=\"{Metadata.TargetTypeFullName}\" />.</summary>");
w.WriteLine ("/// <remarks>NO VALIDATION IS PERFORMED!</remarks>");
w.WriteLine (
$"/// <returns>True, if all flags present in <paramref name=\"checkFlags\" /> are also present in the current value of the <see cref=\"{Metadata.TargetTypeFullName}\" />.<br />Otherwise false.</returns>");
w.WriteLine (Strings.DotnetNames.Attributes.Applications.AggressiveInlining);
w.Push (
$"{Metadata.Accessibility.ToCSharpString ()} static bool FastHasFlags (this {Metadata.TargetTypeFullName} e, {Metadata.TargetTypeFullName} checkFlags)");
w.WriteLine ($"ref uint enumCurrentValueRef = ref Unsafe.As<{Metadata.TargetTypeFullName},uint> (ref e);");
w.WriteLine ($"ref uint checkFlagsValueRef = ref Unsafe.As<{Metadata.TargetTypeFullName},uint> (ref checkFlags);");
w.WriteLine ("return (enumCurrentValueRef & checkFlagsValueRef) == checkFlagsValueRef;");
w.Pop ();
// The version taking the underlying type of the enum as the check value.
w.WriteLine (
$"/// <summary>Determines if the specified mask bits are set in the current value of this <see cref=\"{Metadata.TargetTypeFullName}\" />.</summary>");
w.WriteLine (
$"/// <param name=\"e\">The <see cref=\"{Metadata.TargetTypeFullName}\" /> value to check against the <paramref name=\"mask\" /> value.</param>");
w.WriteLine ("/// <param name=\"mask\">A mask to apply to the current value.</param>");
w.WriteLine (
$"/// <returns>True, if all bits set to 1 in the mask are also set to 1 in the current value of the <see cref=\"{Metadata.TargetTypeFullName}\" />.<br />Otherwise false.</returns>");
w.WriteLine ("/// <remarks>NO VALIDATION IS PERFORMED!</remarks>");
w.WriteLine (Strings.DotnetNames.Attributes.Applications.AggressiveInlining);
w.Push (
$"{Metadata.Accessibility.ToCSharpString ()} static bool FastHasFlags (this {Metadata.TargetTypeFullName} e, {EnumTypeKeyword} mask)");
w.WriteLine ($"ref {EnumTypeKeyword} enumCurrentValueRef = ref Unsafe.As<{Metadata.TargetTypeFullName},{EnumTypeKeyword}> (ref e);");
w.WriteLine ("return (enumCurrentValueRef & mask) == mask;");
w.Pop ();
}
/// <summary>
/// Creates the code for the FastIsDefined method.
/// </summary>
[SuppressMessage ("ReSharper", "SwitchStatementHandlesSomeKnownEnumValuesWithDefault", Justification = "Only need to handle int and uint.")]
[SuppressMessage ("ReSharper", "SwitchStatementMissingSomeEnumCasesNoDefault", Justification = "Only need to handle int and uint.")]
private void GetFastIsDefinedMethod (IndentedTextWriter w)
{
w.WriteLine (
$"/// <summary>Determines if the specified <see langword=\"{EnumTypeKeyword}\" /> value is explicitly defined as a named value of the <see cref=\"{Metadata.TargetTypeFullName}\" /> <see langword=\"enum\" /> type.</summary>");
w.WriteLine (
"/// <remarks>Only explicitly named values return true, as with IsDefined. Combined valid flag values of flags enums which are not explicitly named will return false.</remarks>");
w.Push (
$"{Metadata.Accessibility.ToCSharpString ()} static bool FastIsDefined (this {Metadata.TargetTypeFullName} e, {EnumTypeKeyword} value)");
w.Push ("return value switch");
switch (Metadata.EnumBackingTypeCode)
{
case TypeCode.Int32:
foreach (int definedValue in Metadata._intMembers)
{
w.WriteLine ($"{definedValue:D} => true,");
}
break;
case TypeCode.UInt32:
foreach (uint definedValue in Metadata._uIntMembers)
{
w.WriteLine ($"{definedValue:D} => true,");
}
break;
}
w.WriteLine ("_ => false");
w.Pop ("};");
w.Pop ();
}
private string GetFullSourceText ()
{
StringBuilder sb = new (
$"""
{Strings.Templates.StandardHeader}
[assembly: {Strings.AssemblyExtendedEnumTypeAttributeFullName} (typeof({Metadata.TargetTypeFullName}), typeof({Metadata.GeneratedTypeFullName}))]
{EnumNamespaceUsingDirective}
{ExtensionClassNamespaceDirective}
{ExtensionClassDeclarationXmlDoc}
{Strings.Templates.AttributesForGeneratedTypes}
{ExtensionsForTypeAttributeLine}
{ExtensionClassDeclarationLine}
""",
4096);
using IndentedTextWriter w = new (new StringWriter (sb));
w.Push ();
GetNamedValuesToInt32Method (w);
GetNamedValuesToUInt32Method (w);
if (Metadata.GenerateFastIsDefined)
{
GetFastIsDefinedMethod (w);
}
if (Metadata.GenerateFastHasFlags)
{
GetFastHasFlagsMethods (w);
}
w.Pop ();
w.Flush ();
return sb.ToString ();
}
[MethodImpl (MethodImplOptions.AggressiveInlining)]
private void GetNamedValuesToInt32Method (IndentedTextWriter w)
{
w.WriteLine (
$"/// <summary>Directly converts this <see cref=\"{Metadata.TargetTypeFullName}\" /> value to an <see langword=\"int\" /> value with the same binary representation.</summary>");
w.WriteLine ("/// <remarks>NO VALIDATION IS PERFORMED!</remarks>");
w.WriteLine (Strings.DotnetNames.Attributes.Applications.AggressiveInlining);
w.Push ($"{Metadata.Accessibility.ToCSharpString ()} static int AsInt32 (this {Metadata.TargetTypeFullName} e)");
w.WriteLine ($"return Unsafe.As<{Metadata.TargetTypeFullName},int> (ref e);");
w.Pop ();
}
[MethodImpl (MethodImplOptions.AggressiveInlining)]
private void GetNamedValuesToUInt32Method (IndentedTextWriter w)
{
w.WriteLine (
$"/// <summary>Directly converts this <see cref=\"{Metadata.TargetTypeFullName}\" /> value to a <see langword=\"uint\" /> value with the same binary representation.</summary>");
w.WriteLine ("/// <remarks>NO VALIDATION IS PERFORMED!</remarks>");
w.WriteLine (Strings.DotnetNames.Attributes.Applications.AggressiveInlining);
w.Push ($"{Metadata.Accessibility.ToCSharpString ()} static uint AsUInt32 (this {Metadata.TargetTypeFullName} e)");
w.WriteLine ($"return Unsafe.As<{Metadata.TargetTypeFullName},uint> (ref e);");
w.Pop ();
}
}