Ease of Maintenance of LINQ Code (2)

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In two previous posts, I developed a somewhat involved query to search through a word processing document for style names and/or paragraph content. This is a query that I’m developing for the PowerTools for Open XML project. In those posts, as I evolved the query, I showed each iteration of it, highlighting the changes I made. This post continues modifying that query:

First, I added a few tests that cause complete code coverage given the attached source document.
Second, I changed the way that I handled XNames in the example, using pre-atomized XName objects in a static class. I highlighted these changes in green. I detailed this approach in this post. I should have developed this query using the pre-atomization approach from the start. My conscience started bothering me, so had to correct the code.
Third, I took Keith’s suggestion from the previous post, and re-wrote ContainsAnyStyles and ContainsAnyContent. The new versions are much smaller and cleaner. In this process, did a minor refactoring to pre-convert search strings to lower case when the search is case insensitive and not using regular expressions.

Hey, if anyone else has any additional suggestions for this query, I’m interested! J

Here is the evolved query:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.IO;
using System.Xml;
using System.Xml.Linq;
using DocumentFormat.OpenXml.Packaging;

public static class LocalExtensions
{
    public static string StringConcatenate<T>(this IEnumerable<T> source,
        Func<T, string> func)
    {
        StringBuilder sb = new StringBuilder();
        foreach (T item in source)
            sb.Append(func(item));
        return sb.ToString();
    }

    public static string StringConcatenate<T>(this IEnumerable<T> source,
        Func<T, string> func, string separator)
    {
        StringBuilder sb = new StringBuilder();
        foreach (T item in source)
            sb.Append(func(item)).Append(separator);
        if (sb.Length > separator.Length)
            sb.Length -= separator.Length;
        return sb.ToString();
    }

    public static XDocument GetXDocument(this OpenXmlPart part)
    {
        XDocument xdoc = part.Annotation<XDocument>();
        if (xdoc != null)
            return xdoc;
        using (StreamReader sr = new StreamReader(part.GetStream()))
        using (XmlReader xr = XmlReader.Create(sr))
            xdoc = XDocument.Load(xr);
        part.AddAnnotation(xdoc);
        return xdoc;
    }
}

public static class W
{
    public static XNamespace w =
      "http://schemas.openxmlformats.org/wordprocessingml/2006/main";

    public static XName style = w + "style";
    public static XName type = w + "type";
    public static XName styleId = w + "styleId";
    public static XName name = w + "name";
    public static XName val = w + "val";
    public static XName basedOn = w + "basedOn";
    public static XName r = w + "r";
    public static XName ins = w + "ins";
    // "default" is not a valid identifier, so must use _default
    public static XName _default = w + "default";
    public static XName body = w + "body";
    public static XName pPr = w + "pPr";
    public static XName pStyle = w + "pStyle";
    public static XName p = w + "p";
    public static XName t = w + "t";
}

class Program
{
    static bool ContainsAnyStyles(IEnumerable<string> stylesToSearch,
        IEnumerable<string> searchStrings)
    {
        return stylesToSearch.Intersect(searchStrings).Any();
    }

    static bool ContainsAnyContent(string stringToSearch, IEnumerable<string> searchStrings,
        IEnumerable<Regex> regularExpressions, bool isRegularExpression, bool caseInsensitive)
    {
        if (isRegularExpression)
            return regularExpressions.Any(r => r.IsMatch(stringToSearch));
        else
            if (caseInsensitive)
                return searchStrings.Any(s => stringToSearch.ToLower().Contains(s));
            else
                return searchStrings.Any(s => stringToSearch.Contains(s));
    }

    static IEnumerable<string> GetAllStyleIdsAndNames(WordprocessingDocument doc, string styleId)
    {
        string localStyleId = styleId;
        yield return styleId;

        string styleNameForFirstStyle = (string)doc
            .MainDocumentPart
            .StyleDefinitionsPart
            .GetXDocument()
            .Root
            .Elements(W.style)
            .Where(e => (string)e.Attribute(W.type) == "paragraph" &&
                (string)e.Attribute(W.styleId) == styleId)
            .Elements(W.name)
            .Attributes(W.val)
            .FirstOrDefault();

        if (styleNameForFirstStyle != null)
            yield return styleNameForFirstStyle;

        while (true)
        {
            XElement style = doc
                .MainDocumentPart
                .StyleDefinitionsPart
                .GetXDocument()
                .Root
                .Elements(W.style)
                .Where(e => (string)e.Attribute(W.type) == "paragraph" &&
                    (string)e.Attribute(W.styleId) == localStyleId)
                .FirstOrDefault();

            if (style == null)
                yield break;

            var basedOn = (string)style
                .Elements(W.basedOn)
                .Attributes(W.val)
                .FirstOrDefault();

            if (basedOn == null)
                yield break;

            yield return basedOn;

            XElement basedOnStyle = doc
                .MainDocumentPart
                .StyleDefinitionsPart
                .GetXDocument()
                .Root
                .Elements(W.style)
                .Where(e => (string)e.Attribute(W.type) == "paragraph" &&
                    (string)e.Attribute(W.styleId) == basedOn)
                .FirstOrDefault();

            string basedOnStyleName = (string)basedOnStyle
                .Elements(W.name)
                .Attributes(W.val)
                .FirstOrDefault();

            if (basedOnStyleName != null)
                yield return basedOnStyleName;

            localStyleId = basedOn;
        }
    }

    static int[] SearchInDocument(WordprocessingDocument doc,
        IEnumerable<string> styleSearchString, IEnumerable<string> contentSearchString,
        bool isRegularExpression, bool caseInsensitive)
    {
        RegexOptions options;
        Regex[] regularExpressions = null;
        if (isRegularExpression && contentSearchString != null)
        {
            if (caseInsensitive)
                options = RegexOptions.IgnoreCase | RegexOptions.Compiled;
            else
                options = RegexOptions.Compiled;
            regularExpressions = contentSearchString
                .Select(s => new Regex(s, options)).ToArray();
        }

        string[] contentSearchStringToUse = null;
        if (contentSearchString != null)
        {
            if (!isRegularExpression && caseInsensitive)
                contentSearchStringToUse = contentSearchString.Select(s => s.ToLower()).ToArray();
            else
                contentSearchStringToUse = contentSearchString.ToArray();
        }

        var defaultStyleName = (string)doc
            .MainDocumentPart
            .StyleDefinitionsPart
            .GetXDocument()
            .Root
            .Elements(W.style)
            .Where(style =>
                (string)style.Attribute(W.type) == "paragraph" &&
                (string)style.Attribute(W._default) == "1")
            .First()
            .Attribute(W.styleId);

        var q1 = doc
            .MainDocumentPart
            .GetXDocument()
            .Root
            .Element(W.body)
            .Elements()
            .Select((p, i) =>
            {
                var styleNode = p
                    .Elements(W.pPr)
                    .Elements(W.pStyle)
                    .FirstOrDefault();
                var styleName = styleNode != null ?
                    (string)styleNode.Attribute(W.val) :
                    defaultStyleName;
                return new
                {
                    Element = p,
                    Index = i,
                    StyleName = styleName
                };
            }
            );

        var q2 = q1
            .Select(i =>
            {
                string text = null;
                if (i.Element.Name == W.p)
                    text = i.Element.Elements()
                        .Where(z => z.Name == W.r || z.Name == W.ins)
                        .Descendants(W.t)
                        .StringConcatenate(element => (string)element);
                else
                    text = i.Element
                        .Descendants(W.p)
                        .StringConcatenate(p => p
                            .Elements()
                            .Where(z => z.Name == W.r || z.Name == W.ins)
                            .Descendants(W.t)
                            .StringConcatenate(element => (string)element),
                            Environment.NewLine
                        );

                return new
                {
                    Element = i.Element,
                    StyleName = i.StyleName,
                    Index = i.Index,
                    Text = text
                };
            }
            );

        var q3 = q2
            .Select(i =>
                new
                {
                    Element = i.Element,
                    StyleName = i.StyleName,
                    Index = i.Index,
                    Text = i.Text,
                    InheritedStyles = GetAllStyleIdsAndNames(doc, i.StyleName).Distinct()
                }
            );

        int[] q4 = null;
        if (styleSearchString != null)
            q4 = q3
                .Where(i => ContainsAnyStyles(i.InheritedStyles, styleSearchString))
                .Select(i => i.Index)
                .ToArray();

        int[] q5 = null;
        if (contentSearchStringToUse != null)
            q5 = q3
             .Where(i => ContainsAnyContent(i.Text, contentSearchStringToUse, regularExpressions,
                 isRegularExpression, caseInsensitive))
             .Select(i => i.Index)
             .ToArray();

        int[] q6 = null;
        if (q4 != null && q5 != null)
            q6 = q4.Intersect(q5).ToArray();
        else
            q6 = q5 != null ? q5 : q4;

        return q6;
    }

    static int[] SearchInDocument(string filename,
        IEnumerable<string> styleSearchString, IEnumerable<string> contentSearchString,
        bool isRegularExpression, bool caseInsensitive)
    {
        using (WordprocessingDocument doc =
               WordprocessingDocument.Open(filename, false))
            return SearchInDocument(doc, styleSearchString, contentSearchString,
                isRegularExpression, caseInsensitive);
    }

    static int[] SearchInDocument(string filename, string styleSearchString,
        string contentSearchString, bool isRegularExpression, bool caseInsensitive)
    {
        return SearchInDocument(filename,
            styleSearchString != null ? new List<string>() { styleSearchString } : null,
            contentSearchString != null ? new List<string>() { contentSearchString } : null,
        isRegularExpression, caseInsensitive);
    }

    static void Main(string[] args)
    {
        Console.WriteLine("Test 1");
        int[] results1 = SearchInDocument(
            "Test.docx", new[] { "Normal" }, new[] { "h.*o", "aaa" }, true, false);
        foreach (var i in results1) Console.WriteLine(i);
        Console.WriteLine(results1.SequenceEqual(new[] { 7, 10 }) ? "Passed" : "Failed");
        Console.WriteLine();

        Console.WriteLine("Test 2");
        int[] results2 = SearchInDocument(
            "Test.docx", new[] { "NotAStyle" }, new[] { "h.*o", "aaa" }, true, false);
        foreach (var i in results2) Console.WriteLine(i);
        Console.WriteLine(results2.SequenceEqual(new int[] { }) ? "Passed" : "Failed");
        Console.WriteLine();

        Console.WriteLine("Test 3");
        int[] results3 = SearchInDocument(
            "Test.docx", new[] { "Heading1" }, null, true, false);
        foreach (var i in results3) Console.WriteLine(i);
        Console.WriteLine(results3.SequenceEqual(new int[] { 0 }) ? "Passed" : "Failed");
        Console.WriteLine();

        Console.WriteLine("Test 4");
        int[] results4 = SearchInDocument(
            "Test.docx", new[] { "Normal" }, new[] { "h.*o", "aaa" }, true, true);
        foreach (var i in results4) Console.WriteLine(i);
        Console.WriteLine(
            results4.SequenceEqual(new int[] { 0, 6, 7, 8, 10 }) ? "Passed" : "Failed");
        Console.WriteLine();

        Console.WriteLine("Test 5");
        int[] results5 = SearchInDocument(
            "Test.docx", null, new[] { "hello", "aaa" }, false, false);
        foreach (var i in results5) Console.WriteLine(i);
        Console.WriteLine(
            results5.SequenceEqual(new int[] { 7, 10 }) ? "Passed" : "Failed");
        Console.WriteLine();

        Console.WriteLine("Test 6");
        int[] results6 = SearchInDocument(
            "Test.docx", null, new[] { "hello", "aaa" }, false, true);
        foreach (var i in results6) Console.WriteLine(i);
        Console.WriteLine(
            results6.SequenceEqual(new int[] { 0, 6, 7, 8, 10 }) ? "Passed" : "Failed");
        Console.WriteLine();

        Console.WriteLine("Test 7");
        int[] results7 = SearchInDocument("Test.docx", "Heading1", "Aaa", false, false);
        foreach (var i in results7) Console.WriteLine(i);
        Console.WriteLine(results7.SequenceEqual(new int[] { 0 }) ? "Passed" : "Failed");
        Console.WriteLine();
    }
}