예제 #1
0
        /// <summary>
        /// Tries to find the node with the smallest width in the <paramref name="sourceFile"/>
        /// that contains the input <paramref name="position"/>, and is deemed acceptable by
        /// <paramref name="isNodeAcceptable"/>.
        /// If the position points to a comment, the resulting node is null.
        /// </summary>
        public static bool TryGetNodeAtPosition(ISourceFile sourceFile, int position, Func <INode, bool> isNodeAcceptable, System.Threading.CancellationToken token, out INode currentNode)
        {
            Contract.Requires(sourceFile != null);
            Contract.Requires(position >= 0);

            INode result = null;

            NodeWalker.TraverseDepthFirstAndSelfInOrder(
                sourceFile,
                node =>
            {
                var startPosition = node.GetNodeStartPositionWithoutTrivia(sourceFile);
                if (result != null && startPosition > position)
                {
                    // We can stop the traversal already because the next node starts after the expected position.
                    // And we know that the traversal is depth first from left to right.
                    return(false);
                }

                if (startPosition <= position && position <= node.End)
                {
                    if (result == null || node.GetNodeWidth(sourceFile) <= result.GetNodeWidth(sourceFile))
                    {
                        if (isNodeAcceptable(node))
                        {
                            result = node;
                        }
                    }
                }

                return(true);
            },
                token);

            currentNode = result;
            return(result != null);
        }