static bool ReadCustomAttributeValue(CustomAttributeHandle handle, PEModule module, out int value)
{
// PEModule.cs
var valueBlob = module.GetCustomAttributeValueOrThrow(handle);
if (!valueBlob.IsNil)
{
// TODO: error checking offset in range
var reader = module.MetadataReader.GetBlobReader(valueBlob);
if (reader.Length > 4)
{
// check prolog
if (reader.ReadByte() == 1 && reader.ReadByte() == 0)
{
// read Int32
if (reader.RemainingBytes >= 4)
{
value = reader.ReadInt32();
return(true);
}
}
}
}
value = default;
return(false);
}
private static IEnumerable <string> GetSupportedLanguages(PEModule peModule, CustomAttributeHandle customAttrHandle)
{
// The DiagnosticAnalyzerAttribute has one constructor, which has a string parameter for the
// first supported language and an array parameter for addition supported languages.
// Parse the argument blob to extract the languages.
BlobReader argsReader = peModule.GetMemoryReaderOrThrow(peModule.GetCustomAttributeValueOrThrow(customAttrHandle));
if (argsReader.Length > 4)
{
// Arguments are present--check prologue.
if (argsReader.ReadByte() == 1 && argsReader.ReadByte() == 0)
{
if (!PEModule.CrackStringInAttributeValue(out string firstLanguageName, ref argsReader))
{
return(SpecializedCollections.EmptyEnumerable <string>());
}
if (PEModule.CrackStringArrayInAttributeValue(out ImmutableArray <string> additionalLanguageNames, ref argsReader))
{
if (additionalLanguageNames.Length == 0)
{
return(SpecializedCollections.SingletonEnumerable(firstLanguageName));
}
return(additionalLanguageNames.Insert(0, firstLanguageName));
}
}
}
return(SpecializedCollections.EmptyEnumerable <string>());
}
private static string GetSupportedLanguage(PEModule peModule, CustomAttributeHandle customAttrHandle)
{
// The DiagnosticAnalyzerAttribute has two constructors:
// 1. Paramterless - means that the analyzer is applicable to any language.
// 2. Single string parameter specifying the language.
// Parse the argument blob to extract these two cases.
BlobReader argsReader = peModule.GetMemoryReaderOrThrow(peModule.GetCustomAttributeValueOrThrow(customAttrHandle));
// Single string parameter
if (argsReader.Length > 4)
{
// check prologue
if (argsReader.ReadByte() == 1 && argsReader.ReadByte() == 0)
{
string languageName;
if (PEModule.CrackStringInAttributeValue(out languageName, ref argsReader))
{
return(languageName);
}
}
}
// otherwise the attribute is applicable to all languages.
else
{
return(string.Empty);
}
return(null);
}
private static IEnumerable <string> GetDiagnosticsAnalyzerSupportedLanguages(PEModule peModule, CustomAttributeHandle customAttrHandle)
{
// The DiagnosticAnalyzerAttribute has one constructor, which has a string parameter for the
// first supported language and an array parameter for additional supported languages.
// Parse the argument blob to extract the languages.
BlobReader argsReader = peModule.GetMemoryReaderOrThrow(peModule.GetCustomAttributeValueOrThrow(customAttrHandle));
return(ReadLanguagesFromAttribute(ref argsReader));
}
private static IEnumerable <string> GetGeneratorSupportedLanguages(PEModule peModule, CustomAttributeHandle customAttrHandle)
{
// The GeneratorAttribute has two constructors: one default, and one with a string parameter for the
// first supported language and an array parameter for additional supported languages.
BlobReader argsReader = peModule.GetMemoryReaderOrThrow(peModule.GetCustomAttributeValueOrThrow(customAttrHandle));
if (argsReader.Length == 4)
{
// default ctor
return(ImmutableArray.Create(LanguageNames.CSharp));
}
else
{
// Parse the argument blob to extract the languages.
return(ReadLanguagesFromAttribute(ref argsReader));
}
}
