/
ArrayForEachMapping.cs
76 lines (64 loc) · 3 KB
/
ArrayForEachMapping.cs
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using static Microsoft.CodeAnalysis.CSharp.SyntaxFactory;
using static Riok.Mapperly.Emit.Syntax.SyntaxFactoryHelper;
namespace Riok.Mapperly.Descriptors.Mappings;
/// <summary>
/// Represents an enumerable to array mapping which works by initialising an array, looping through the source,
/// mapping each element and adding it to the target array.
/// </summary>
public class ArrayForEachMapping : MethodMapping
{
private const string TargetVariableName = "target";
private const string LoopItemVariableName = "item";
private const string LoopCounterName = "i";
private readonly INewInstanceMapping _elementMapping;
private readonly ITypeSymbol _targetArrayElementType;
private readonly string _countPropertyName;
public ArrayForEachMapping(
ITypeSymbol sourceType,
ITypeSymbol targetType,
INewInstanceMapping elementMapping,
ITypeSymbol targetArrayElementType,
string countPropertyName
)
: base(sourceType, targetType)
{
_elementMapping = elementMapping;
_targetArrayElementType = targetArrayElementType;
_countPropertyName = countPropertyName;
}
public override IEnumerable<StatementSyntax> BuildBody(TypeMappingBuildContext ctx)
{
var targetVariableName = ctx.NameBuilder.New(TargetVariableName);
var loopCounterVariableName = ctx.NameBuilder.New(LoopCounterName);
// var target = new T[source.Count];
var sourceLengthArrayRank = ArrayRankSpecifier(
SingletonSeparatedList<ExpressionSyntax>(MemberAccess(ctx.Source, _countPropertyName))
);
var targetInitializationValue = CreateArray(
ArrayType(FullyQualifiedIdentifier(_targetArrayElementType)).WithRankSpecifiers(SingletonList(sourceLengthArrayRank))
);
yield return ctx.SyntaxFactory.DeclareLocalVariable(targetVariableName, targetInitializationValue);
// var i = 0;
yield return ctx.SyntaxFactory.DeclareLocalVariable(loopCounterVariableName, IntLiteral(0));
// target[i] = Map(item);
var (loopItemCtx, loopItemVariableName) = ctx.WithNewSource(LoopItemVariableName);
var convertedSourceItemExpression = _elementMapping.Build(loopItemCtx.AddIndentation());
var assignment = Assignment(
ElementAccess(IdentifierName(targetVariableName), IdentifierName(loopCounterVariableName)),
convertedSourceItemExpression
);
// i++;
var counterIncrement = PostfixUnaryExpression(SyntaxKind.PostIncrementExpression, IdentifierName(loopCounterVariableName));
// foreach(var item in source)
//{
// target[i] = Map(item);
// i++;
//}
yield return ctx.SyntaxFactory.ForEach(loopItemVariableName, ctx.Source, assignment, counterIncrement);
// return target;
yield return ctx.SyntaxFactory.ReturnVariable(targetVariableName);
}
}