C# ArrayBuilder.Clear方法代码示例

        internal static void FillUsedEnumFields(ArrayBuilder<EnumField> usedFields, ArrayBuilder<EnumField> fields, ulong underlyingValue)
        {
            var remaining = underlyingValue;
            foreach (var field in fields)
            {
                var fieldValue = field.Value;
                if (fieldValue == 0) continue; // Otherwise, we'd tack the zero flag onto everything.

                if ((remaining & fieldValue) == fieldValue)
                {
                    remaining -= fieldValue;

                    usedFields.Add(field);

                    if (remaining == 0) break;
                }
            }

            // The value contained extra bit flags that didn't correspond to any enum field.  We will
            // report "no fields used" here so the Formatter will just display the underlying value.
            if (remaining != 0)
            {
                usedFields.Clear();
            }
        }

        internal override ReadOnlyCollection<byte> CompileGetLocals(
            ReadOnlyCollection<Alias> aliases,
            ArrayBuilder<LocalAndMethod> locals,
            bool argumentsOnly,
            DiagnosticBag diagnostics,
            out string typeName,
            Microsoft.CodeAnalysis.CodeGen.CompilationTestData testData)
        {
            var context = this.CreateCompilationContext(null);
            var moduleBuilder = context.CompileGetLocals(aliases, TypeName, locals, argumentsOnly, testData, diagnostics);
            ReadOnlyCollection<byte> assembly = null;

            if ((moduleBuilder != null) && (locals.Count > 0))
            {
                using (var stream = new MemoryStream())
                {
                    Cci.PeWriter.WritePeToStream(
                        new EmitContext((Cci.IModule)moduleBuilder, null, diagnostics),
                        context.MessageProvider,
                        () => stream,
                        nativePdbWriterOpt: null,
                        pdbPathOpt: null,
                        allowMissingMethodBodies: false,
                        deterministic: false,
                        cancellationToken: default(CancellationToken));

                    if (!diagnostics.HasAnyErrors())
                    {
                        assembly = new ReadOnlyCollection<byte>(stream.ToArray());
                    }
                }
            }

            if (assembly == null)
            {
                locals.Clear();
                assembly = s_emptyBytes;
            }

            typeName = TypeName;
            return assembly;
        }

        private bool GetUserDefinedOperators(
            BinaryOperatorKind kind,
            TypeSymbol type0,
            BoundExpression left,
            BoundExpression right,
            ArrayBuilder<BinaryOperatorAnalysisResult> results,
            ref HashSet<DiagnosticInfo> useSiteDiagnostics)
        {
            // Spec 7.3.5 Candidate user-defined operators
            // SPEC: Given a type T and an operation operator op(A), where op is an overloadable 
            // SPEC: operator and A is an argument list, the set of candidate user-defined operators 
            // SPEC: provided by T for operator op(A) is determined as follows:

            // SPEC: Determine the type T0. If T is a nullable type, T0 is its underlying type, 
            // SPEC: otherwise T0 is equal to T.

            // (The caller has already passed in the stripped type.)

            // SPEC: For all operator op declarations in T0 and all lifted forms of such operators, 
            // SPEC: if at least one operator is applicable (7.5.3.1) with respect to the argument 
            // SPEC: list A, then the set of candidate operators consists of all such applicable 
            // SPEC: operators in T0. Otherwise, if T0 is object, the set of candidate operators is empty.
            // SPEC: Otherwise, the set of candidate operators provided by T0 is the set of candidate 
            // SPEC: operators provided by the direct base class of T0, or the effective base class of
            // SPEC: T0 if T0 is a type parameter.

            string name = OperatorFacts.BinaryOperatorNameFromOperatorKind(kind);
            var operators = ArrayBuilder<BinaryOperatorSignature>.GetInstance();
            bool hadApplicableCandidates = false;

            NamedTypeSymbol current = type0 as NamedTypeSymbol;
            if ((object)current == null)
            {
                current = type0.BaseTypeWithDefinitionUseSiteDiagnostics(ref useSiteDiagnostics);
            }

            if ((object)current == null && type0.IsTypeParameter())
            {
                current = ((TypeParameterSymbol)type0).EffectiveBaseClass(ref useSiteDiagnostics);
            }

            for (; (object)current != null; current = current.BaseTypeWithDefinitionUseSiteDiagnostics(ref useSiteDiagnostics))
            {
                operators.Clear();
                GetUserDefinedBinaryOperatorsFromType(current, kind, name, operators);
                results.Clear();
                if (CandidateOperators(operators, left, right, results, ref useSiteDiagnostics))
                {
                    hadApplicableCandidates = true;
                    break;
                }
            }

            operators.Free();

            return hadApplicableCandidates;
        }

        // Returns true if there were any applicable candidates.
        private bool GetUserDefinedOperators(UnaryOperatorKind kind, BoundExpression operand, ArrayBuilder<UnaryOperatorAnalysisResult> results, ref HashSet<DiagnosticInfo> useSiteDiagnostics)
        {
            Debug.Assert(operand != null);

            if ((object)operand.Type == null)
            {
                // If the operand has no type -- because it is a null reference or a lambda or a method group --
                // there is no way we can determine what type to search for user-defined operators.
                return false;
            }

            // Spec 7.3.5 Candidate user-defined operators
            // SPEC: Given a type T and an operation op(A) ... the set of candidate user-defined 
            // SPEC: operators provided by T for op(A) is determined as follows:

            // SPEC: If T is a nullable type then T0 is its underlying type; otherwise T0 is T.
            // SPEC: For all operator declarations in T0 and all lifted forms of such operators, if
            // SPEC: at least one operator is applicable with respect to A then the set of candidate
            // SPEC: operators consists of all such applicable operators. Otherwise, if T0 is object
            // SPEC: then the set of candidate operators is empty. Otherwise, the set of candidate
            // SPEC: operators is the set provided by the direct base class of T0, or the effective
            // SPEC: base class of T0 if T0 is a type parameter.

            TypeSymbol type0 = operand.Type.StrippedType();

            // Searching for user-defined operators is expensive; let's take an early out if we can.
            if (OperatorFacts.DefinitelyHasNoUserDefinedOperators(type0))
            {
                return false;
            }

            string name = OperatorFacts.UnaryOperatorNameFromOperatorKind(kind);
            var operators = ArrayBuilder<UnaryOperatorSignature>.GetInstance();
            bool hadApplicableCandidates = false;

            NamedTypeSymbol current = type0 as NamedTypeSymbol;
            if ((object)current == null)
            {
                current = type0.BaseTypeWithDefinitionUseSiteDiagnostics(ref useSiteDiagnostics);
            }

            if ((object)current == null && type0.IsTypeParameter())
            {
                current = ((TypeParameterSymbol)type0).EffectiveBaseClass(ref useSiteDiagnostics);
            }

            for (; (object)current != null; current = current.BaseTypeWithDefinitionUseSiteDiagnostics(ref useSiteDiagnostics))
            {
                operators.Clear();
                GetUserDefinedUnaryOperatorsFromType(current, kind, name, operators);
                results.Clear();
                if (CandidateOperators(operators, operand, results, ref useSiteDiagnostics))
                {
                    hadApplicableCandidates = true;
                    break;
                }
            }

            operators.Free();

            return hadApplicableCandidates;
        }

        internal void LookupExtensionMethodsInUsings(
            ArrayBuilder<MethodSymbol> methods,
            string name,
            int arity,
            LookupOptions options,
            bool callerIsSemanticModel)
        {
            Debug.Assert(methods.Count == 0);

            // We need to avoid collecting multiple candidates for an extension method imported both through a namespace and a static class
            // We will look for duplicates only if both of the following flags are set to true
            bool seenNamespaceWithExtensionMethods = false;
            bool seenStaticClassWithExtensionMethods = false;

            foreach (var nsOrType in this.Usings)
            {
                switch (nsOrType.NamespaceOrType.Kind)
                {
                    case SymbolKind.Namespace:
                        {
                            var count = methods.Count;
                            ((NamespaceSymbol)nsOrType.NamespaceOrType).GetExtensionMethods(methods, name, arity, options);

                            // If we found any extension methods, then consider this using as used.
                            if (methods.Count != count)
                            {
                                MarkImportDirective(nsOrType.UsingDirective, callerIsSemanticModel);
                                seenNamespaceWithExtensionMethods = true;
                            }

                            break;
                        }

                    case SymbolKind.NamedType:
                        {
                            var count = methods.Count;
                            ((NamedTypeSymbol)nsOrType.NamespaceOrType).GetExtensionMethods(methods, name, arity, options);

                            // If we found any extension methods, then consider this using as used.
                            if (methods.Count != count)
                            {
                                MarkImportDirective(nsOrType.UsingDirective, callerIsSemanticModel);
                                seenStaticClassWithExtensionMethods = true;
                            }

                            break;
                        }
                }
            }

            if (seenNamespaceWithExtensionMethods && seenStaticClassWithExtensionMethods)
            {
                var methodsNoDuplicates = ArrayBuilder<MethodSymbol>.GetInstance();
                methodsNoDuplicates.AddRange(methods.Distinct());
                if (methodsNoDuplicates.Count < methods.Count)
                {
                    methods.Clear();
                    methods.AddRange(methodsNoDuplicates);
                }

                methodsNoDuplicates.Free();
            }
        }

        /// <summary>
        /// Trim excessive inaccessible text.
        /// </summary>
        private static void TrimInaccessibleText(ArrayBuilder<SourceText> segments)
        {
            int length, size;
            ComputeLengthAndStorageSize(segments, out length, out size);

            // if more than half of the storage is unused, compress into a single new segment
            if (length < size / 2)
            {
                var encoding = segments[0].Encoding;
                var algorithm = segments[0].ChecksumAlgorithm;

                var writer = SourceTextWriter.Create(encoding, algorithm, length);
                foreach (var segment in segments)
                {
                    segment.Write(writer);
                }

                segments.Clear();
                segments.Add(writer.ToSourceText());
            }
        }