SharePoint CAML Query Builder Dialog for your Web Parts

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Diagnostics;

namespace Mullivan.Logging
{
    public static class ProductLog
    {
        private const string CLOSEDOCUMENT = "</entries>";
        private const string CLOSEENTRY = "\t</entry>\r\n";
        private static DateTime currentDate;
        private const string DECLARATION = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\" ?>\r\n";
        private static string directoryPath;
        private const string FILENAMEEXTENSION = ".log";
        private const string FILENAMEFORMAT = "MMddyyyy";
        private const string FILENAMEPREFIX = "ML";
        private const int MAXATTEMPTS = 5;
        private const string MESSAGE = "\t\t<message>\r\n\t\t\t{0}\r\n\t\t</message>\r\n";
        private const string OPENDOCUMENT = "<entries>\r\n";
        private const string OPENENTRY = "\t<entry entryData=\"{0}\" componentName=\"{1}\" machineName=\"{2}\" category=\"{3}\">\r\n";
        private const string STACKTRACE = "\t\t<stackTrace>\r\n\t\t\t{0}\r\n\t\t</stackTrace>\r\n";
        private const string TRACETEMPLATE = "Logging Error:\r\n\r\n\tMessage: {0}\r\n\tStack Trace: {1}\r\n\r\n\r\nCould not write the following to log file:\r\n\r\n\tEntry Date: {2}\r\n\tComponent Name: {3}\r\n\tMachine Name: {4}\r\n\tCategory: {5}\r\n\tMessage: {6}\r\n\tStack Trace: {7}";

        static ProductLog()
        {
            directoryPath = Path.GetFullPath("Logs");
            currentDate = DateTime.MinValue;
        }

        public static string DirectoryPath
        {
            get
            {
                return directoryPath;
            }
            set
            {
                directoryPath = Path.GetFullPath(value);
            }
        }

        public static string GetLogFilePath(DateTime logDate)
        {
            return Path.Combine(directoryPath, FILENAMEPREFIX + logDate.ToString("MMddyyyy") + ".log");
        }

        public static void WriteEntry(string componentName, ProductLogCategory category, Exception ex)
        {
            WriteEntry(componentName, category, ex.Message, ex.StackTrace);
        }

        public static void WriteEntry(string componentName, ProductLogCategory category, string message)
        {
            WriteEntry(componentName, category, message, string.Empty);
        }

        public static void WriteEntry(string componentName, ProductLogCategory category, string message, string stackTrace)
        {
            AttemptEntry(1, componentName, category, message, stackTrace);
        }

        private static void AttemptEntry(int attempt, string componentName, ProductLogCategory category, string message, string stackTrace)
        {
            try
            {
                try
                {
                    string logFilePath = GetLogFilePath(DateTime.Today);
                    string directoryName = Path.GetDirectoryName(logFilePath);
                    if (!Directory.Exists(directoryName))
                    {
                        Directory.CreateDirectory(directoryName);
                    }
                    using (FileStream stream = new FileStream(logFilePath, FileMode.OpenOrCreate, FileAccess.ReadWrite))
                    {
                        if (stream.Length == 0L)
                        {
                            WriteToStream(stream, "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\" ?>\r\n");
                            WriteToStream(stream, "<entries>\r\n");
                        }
                        else
                        {
                            int length = "</entries>".Length;
                            if (stream.Length >= length)
                            {
                                stream.Seek((long)-length, SeekOrigin.End);
                            }
                        }
                        WriteToStream(stream, string.Format("\t<entry entryData=\"{0}\" componentName=\"{1}\" machineName=\"{2}\" category=\"{3}\">\r\n", new object[] { DateTime.Now.ToString(), componentName, Environment.MachineName, category.ToString() }));
                        if (message.Length > 0)
                        {
                            WriteToStream(stream, string.Format("\t\t<message>\r\n\t\t\t{0}\r\n\t\t</message>\r\n", Escape(message)));
                        }
                        if (stackTrace.Length > 0)
                        {
                            WriteToStream(stream, string.Format("\t\t<stackTrace>\r\n\t\t\t{0}\r\n\t\t</stackTrace>\r\n", Escape(stackTrace)));
                        }
                        WriteToStream(stream, string.Format("\t</entry>\r\n", new object[0]));
                        WriteToStream(stream, "</entries>");
                    }
                }
                catch (IOException)
                {
                    if (attempt > 5)
                    {
                        throw;
                    }
                    AttemptEntry(++attempt, componentName, category, message, stackTrace);
                }
            }
            catch (Exception exception)
            {
                Trace.WriteLine(string.Format("Logging Error:\r\n\r\n\tMessage: {0}\r\n\tStack Trace: {1}\r\n\r\n\r\nCould not write the following to log file:\r\n\r\n\tEntry Date: {2}\r\n\tComponent Name: {3}\r\n\tMachine Name: {4}\r\n\tCategory: {5}\r\n\tMessage: {6}\r\n\tStack Trace: {7}", new object[] { exception.Message, exception.StackTrace, DateTime.Now.ToString(), componentName, Environment.MachineName, category.ToString(), message, stackTrace }));
            }
        }

        private static string Escape(string str)
        {
            StringBuilder builder = new StringBuilder();
            if (str != null)
            {
                int startIndex = 0;
                for (int i = 0; i < str.Length; i++)
                {
                    switch (str[i])
                    {
                        case '&':
                            builder.Append(str.Substring(startIndex, i - startIndex));
                            builder.Append("&amp;");
                            startIndex = i + 1;
                            break;

                        case '\'':
                            builder.Append(str.Substring(startIndex, i - startIndex));
                            builder.Append("&apos;");
                            startIndex = i + 1;
                            break;

                        case '"':
                            builder.Append(str.Substring(startIndex, i - startIndex));
                            builder.Append("&quot;");
                            startIndex = i + 1;
                            break;

                        case '<':
                            builder.Append(str.Substring(startIndex, i - startIndex));
                            builder.Append("&lt;");
                            startIndex = i + 1;
                            break;

                        case '>':
                            builder.Append(str.Substring(startIndex, i - startIndex));
                            builder.Append("&gt;");
                            startIndex = i + 1;
                            break;
                    }
                }
                builder.Append(str.Substring(startIndex, str.Length - startIndex));
            }
            return builder.ToString();
        }

        private static void WriteToStream(FileStream fs, string text)
        {
            fs.Write(Encoding.UTF8.GetBytes(text), 0, Encoding.UTF8.GetByteCount(text));
        }

    }
}