developer/Samples/NET 4.6/Samples for Parallel/ParallelGrep/ParallelGrep_CSharp/ParallelGrep.cs

   1 //--------------------------------------------------------------------------
   2 //
   3 //  Copyright (c) Microsoft Corporation.  All rights reserved.
   4 //
   5 //  File: ParallelGrep.cs
   6 //
   7 //--------------------------------------------------------------------------
   8
   9 using System;
  10 using System.IO;
  11 using System.Linq;
  12 using System.Text.RegularExpressions;
  13 using System.Threading;
  14
  15 class ParallelGrep
  16 {
  17     static void Main(string[] args)
  18     {
  19         // Parse command-line switches
  20         bool recursive = args.Contains("/s");
  21         bool ignoreCase = args.Contains("/i");
  22
  23         // Get the regex and file wildcards from the command-line
  24         var nonSwitches = from arg in args where arg.FirstOrDefault() != '/' select arg;
  25         var regexString = nonSwitches.FirstOrDefault();
  26         var wildcards = nonSwitches.Skip(1);
  27
  28         // Create thread-local Regex instances, to prevent contention on Regex's internal lock
  29         var regex = new ThreadLocal<Regex>(() =>
  30             new Regex(regexString, RegexOptions.Compiled | (ignoreCase ? RegexOptions.IgnoreCase : RegexOptions.None)));
  31
  32         // Get the list of files to be examined
  33         var files = from wc in wildcards
  34                     let dirName = Path.GetDirectoryName(wc)
  35                     let fileName = Path.GetFileName(wc)
  36                     from file in Directory.EnumerateFiles(
  37                         String.IsNullOrWhiteSpace(dirName) ? "." : dirName,
  38                         String.IsNullOrWhiteSpace(fileName) ? "*.*" : fileName,
  39                         recursive ? SearchOption.AllDirectories : SearchOption.TopDirectoryOnly)
  40                     select file;
  41
  42         try
  43         {
  44             // Traverse the specified files in parallel, and run each line through the Regex, collecting line number info
  45             // for each match (the Zip call counts the lines in each file)
  46             var matches = from file in files.AsParallel().AsOrdered().WithMergeOptions(ParallelMergeOptions.NotBuffered)
  47                           from line in File.ReadLines(file).Zip(Enumerable.Range(1, int.MaxValue), (s, i) => new { Num = i, Text = s, File = file })
  48                           where regex.Value.IsMatch(line.Text)
  49                           select line;
  50             foreach (var line in matches)
  51             {
  52                 Console.WriteLine("{0}:{1} {2}", line.File, line.Num, line.Text);
  53             }
  54         }
  55         catch (AggregateException ae)
  56         {
  57             ae.Handle(e => { Console.WriteLine(e.Message); return true; });
  58         }
  59     }
  60 }