private static Parser?GetParser(
Compilation compilation,
AttributedMembers attrMembers,
DeserializerTypes types,
ITypeSymbol toParseType,
Location?location,
ImmutableArray <AttributeSyntax> attrs,
ref ImmutableArray <Diagnostic> diags
)
{
var parser =
Utils.GetMethodFromAttribute(
attrMembers,
"ParserType",
Diagnostics.ParserTypeSpecifiedMultipleTimes,
"ParserMethodName",
Diagnostics.ParserMethodNameSpecifiedMultipleTimes,
Diagnostics.ParserBothMustBeSet,
location,
attrs,
ref diags
);
if (parser == null)
{
return(null);
}
var(type, name) = parser.Value;
var parserMtd = Utils.GetMethod(type, name, location, ref diags);
if (parserMtd == null)
{
return(null);
}
var methodReturnType = parserMtd.ReturnType;
if (methodReturnType.SpecialType != SpecialType.System_Boolean)
{
var diag = Diagnostics.MethodMustReturnBool(location, parserMtd);
diags = diags.Add(diag);
return(null);
}
if (!parserMtd.IsStatic)
{
var diag = Diagnostics.MethodNotStatic(location, parserMtd);
diags = diags.Add(diag);
return(null);
}
var accessible = parserMtd.IsAccessible(attrMembers);
if (!accessible)
{
var diag = Diagnostics.MethodNotPublicOrInternal(location, parserMtd);
diags = diags.Add(diag);
return(null);
}
var ps = parserMtd.Parameters;
if (ps.Length != 3)
{
var diag = Diagnostics.BadParserParameters(location, parserMtd);
diags = diags.Add(diag);
return(null);
}
// Parameters
// * ReadOnlySpan(char)
// * in ReadContext,
// * out assignable to outputType
var p0 = ps[0];
if (!p0.IsNormalParameterOfType(compilation, types.Framework.ReadOnlySpanOfChar))
{
var diag = Diagnostics.BadParserParameters(location, parserMtd);
diags = diags.Add(diag);
return(null);
}
var p1 = ps[1];
if (!p1.IsInReadContext(types.OurTypes))
{
var diag = Diagnostics.BadParserParameters(location, parserMtd);
diags = diags.Add(diag);
return(null);
}
var p2 = ps[2];
if (p2.RefKind != RefKind.Out)
{
var diag = Diagnostics.BadParserParameters(location, parserMtd);
diags = diags.Add(diag);
return(null);
}
var conversion = compilation.ClassifyConversion(p2.Type, toParseType);
var canConvert = conversion.IsImplicit || conversion.IsIdentity;
if (!canConvert)
{
var diag = Diagnostics.BadParserParameters(location, parserMtd);
diags = diags.Add(diag);
return(null);
}
return(new Parser(parserMtd, p2.Type));
}
