C# HashSet.IsNullOrEmpty方法代码示例

 /// <summary>
 /// Adds diagnostics from useSiteDiagnostics into diagnostics and returns True if there were any errors.
 /// </summary>
 internal static bool Add(
     this DiagnosticBag diagnostics,
     CSharpSyntaxNode node,
     HashSet<DiagnosticInfo> useSiteDiagnostics)
 {
     return !useSiteDiagnostics.IsNullOrEmpty() && diagnostics.Add(node.Location, useSiteDiagnostics);
 }

        /// <summary>
        /// Appends diagnostics from useSiteDiagnostics into diagnostics and returns True if there were any errors.
        /// </summary>
        internal static bool AppendUseSiteDiagnostics(
            SyntaxNode node,
            HashSet<DiagnosticInfo> useSiteDiagnostics,
            DiagnosticBag diagnostics)
        {
            if (useSiteDiagnostics.IsNullOrEmpty())
            {
                return false;
            }

            bool haveErrors = false;

            foreach (var info in useSiteDiagnostics)
            {
                if (info.Severity == DiagnosticSeverity.Error)
                {
                    haveErrors = true;
                }

                Error(diagnostics, info, node);
            }

            return haveErrors;
        }

        private static bool AppendUseSiteDiagnostics(
            HashSet<DiagnosticInfo> useSiteDiagnostics,
            TypeParameterSymbol typeParameter,
            ref ArrayBuilder<TypeParameterDiagnosticInfo> useSiteDiagnosticsBuilder)
        {
            if (useSiteDiagnostics.IsNullOrEmpty())
            {
                return false;
            }

            if (useSiteDiagnosticsBuilder == null)
            {
                useSiteDiagnosticsBuilder = new ArrayBuilder<TypeParameterDiagnosticInfo>();
            }

            bool hasErrors = false;

            foreach (var info in useSiteDiagnostics)
            {
                if (info.Severity == DiagnosticSeverity.Error)
                {
                    hasErrors = true;
                }

                useSiteDiagnosticsBuilder.Add(new TypeParameterDiagnosticInfo(typeParameter, info));
            }

            return hasErrors;
        }

        /// <summary>
        /// Select from DOM using index. First non-class/tag/id selector will result in this being passed off to GetMatches
        /// </summary>
        /// <param name="document"></param>
        /// <returns></returns>
        public IEnumerable<IDomObject> Select(IDomDocument document, IEnumerable<IDomObject> context)
        {
            if (Selectors == null )
            {
                throw new ArgumentException("No selectors provided.");
            }
            if (Selectors.Count == 0)
            {
                yield break;
            }
            Document = document;
            IEnumerable<IDomObject> lastResult = null;
            HashSet<IDomObject> output = new HashSet<IDomObject>();
            IEnumerable<IDomObject> selectionSource = context;

            // Disable the index if there is no context (e.g. disconnected elements)
            bool useIndex = context.IsNullOrEmpty() || !context.First().IsDisconnected;

            // Copy the list because it may change during the process
            ActiveSelectors = new List<Selector>(Selectors);

            for (activeSelectorId = 0; activeSelectorId < ActiveSelectors.Count; activeSelectorId++)
            {
                var selector = ActiveSelectors[activeSelectorId];
                CombinatorType combinatorType = selector.CombinatorType;
                SelectorType selectorType = selector.SelectorType;
                TraversalType traversalType = selector.TraversalType;

                // Determine what kind of combining method we will use with previous selection results

                if (activeSelectorId != 0)
                {
                    switch (combinatorType)
                    {
                        case CombinatorType.Cumulative:
                            // do nothing
                            break;
                        case CombinatorType.Root:
                            selectionSource = context;
                            if (lastResult != null)
                            {
                                output.AddRange(lastResult);
                                lastResult = null;
                            }
                            break;
                        case CombinatorType.Chained:
                            selectionSource = lastResult;
                            lastResult = null;
                            break;
                        // default (chained): leave lastresult alone
                    }
                }

                HashSet<IDomObject> tempResult = null;
                IEnumerable<IDomObject> interimResult = null;

                string key = "";
                if (useIndex && !selector.NoIndex)
                {

            #if DEBUG_PATH

                    if (type.HasFlag(SelectorType.Attribute))
                    {
                        key = "!" + selector.AttributeName;
                        type &= ~SelectorType.Attribute;
                        if (selector.AttributeValue != null)
                        {
                            InsertAttributeValueSelector(selector);
                        }
                    }
                    else if (type.HasFlag(SelectorType.Tag))
                    {
                        key = "+"+selector.Tag;
                        type &= ~SelectorType.Tag;
                    }
                    else if (type.HasFlag(SelectorType.ID))
                    {
                        key = "#" + selector.ID;
                        type &= ~SelectorType.ID;
                    }
                    else if (type.HasFlag(SelectorType.Class))
                    {
                        key = "." + selector.Class;
                        type &= ~SelectorType.Class;
                    }

            #else
                    if (selectorType.HasFlag(SelectorType.Attribute))
                    {
                        key = "!" + (char)DomData.TokenID(selector.AttributeName);
                        selectorType &= ~SelectorType.Attribute;
                        if (selector.AttributeValue != null)
                        {
                            InsertAttributeValueSelector(selector);
//.........这里部分代码省略.........