private bool TryCreateImportDefinition()

in src/Microsoft.VisualStudio.Composition/Configuration/AttributedPartDiscoveryV1.cs [281:348]
58 lines of code
13 McCabe index (conditional complexity)

        private bool TryCreateImportDefinition(Type importingType, ICustomAttributeProvider member, [NotNullWhen(true)] out ImportDefinition? importDefinition)
        {
            Requires.NotNull(importingType, nameof(importingType));
            Requires.NotNull(member, nameof(member));

            ImportAttribute importAttribute = member.GetFirstAttribute<ImportAttribute>();
            ImportManyAttribute importManyAttribute = member.GetFirstAttribute<ImportManyAttribute>();

            // Importing constructors get implied attributes on their parameters.
            if (importAttribute == null && importManyAttribute == null && member is ParameterInfo)
            {
                importAttribute = new ImportAttribute();
            }

            if (importAttribute != null)
            {
                this.ThrowOnInvalidImportingMemberOrParameter(member, isImportMany: false);

                if (importAttribute.Source != ImportSource.Any)
                {
                    throw new NotSupportedException(Strings.CustomImportSourceNotSupported);
                }

                var requiredCreationPolicy = importingType.IsExportFactoryTypeV1()
                    ? CreationPolicy.NonShared
                    : (CreationPolicy)importAttribute.RequiredCreationPolicy;

                Type contractType = importAttribute.ContractType ?? GetTypeIdentityFromImportingType(importingType, importMany: false);
                var constraints = PartCreationPolicyConstraint.GetRequiredCreationPolicyConstraints(requiredCreationPolicy)
                    .Union(this.GetMetadataViewConstraints(importingType, importMany: false))
                    .Union(GetExportTypeIdentityConstraints(contractType));
                importDefinition = new ImportDefinition(
                    string.IsNullOrEmpty(importAttribute.ContractName) ? GetContractName(contractType) : importAttribute.ContractName!,
                    importAttribute.AllowDefault ? ImportCardinality.OneOrZero : ImportCardinality.ExactlyOne,
                    GetImportMetadataForGenericTypeImport(contractType),
                    constraints);
                return true;
            }
            else if (importManyAttribute != null)
            {
                this.ThrowOnInvalidImportingMemberOrParameter(member, isImportMany: true);

                if (importManyAttribute.Source != ImportSource.Any)
                {
                    throw new NotSupportedException(Strings.CustomImportSourceNotSupported);
                }

                var requiredCreationPolicy = GetElementTypeFromMany(importingType).IsExportFactoryTypeV1()
                    ? CreationPolicy.NonShared
                    : (CreationPolicy)importManyAttribute.RequiredCreationPolicy;

                Type contractType = importManyAttribute.ContractType ?? GetTypeIdentityFromImportingType(importingType, importMany: true);
                var constraints = PartCreationPolicyConstraint.GetRequiredCreationPolicyConstraints(requiredCreationPolicy)
                    .Union(this.GetMetadataViewConstraints(importingType, importMany: true))
                    .Union(GetExportTypeIdentityConstraints(contractType));
                importDefinition = new ImportDefinition(
                    string.IsNullOrEmpty(importManyAttribute.ContractName) ? GetContractName(contractType) : importManyAttribute.ContractName!,
                    ImportCardinality.ZeroOrMore,
                    GetImportMetadataForGenericTypeImport(contractType),
                    constraints);
                return true;
            }
            else
            {
                importDefinition = null;
                return false;
            }
        }