CabDiffEngine.cs :  » Installers-Generators » WiX » Microsoft » Deployment » Samples » DDiff » C# / CSharp Open Source

using System;
using System.IO;
using System.Collections;
using System.Collections.Generic;
using Microsoft.Deployment.Compression.Cab;

namespace Microsoft.Deployment.Samples.DDiff{
  public class CabDiffEngine : IDiffEngine
  {
    public CabDiffEngine()
    {
    }

    private bool IsCabinetFile(string file)
    {
      using(FileStream fileStream = File.OpenRead(file))
      {
        return new CabEngine().IsArchive(fileStream);
      }
    }

    public virtual float GetDiffQuality(string diffInput1, string diffInput2, string[] options, IDiffEngineFactory diffFactory)
    {
      if(diffInput1 != null && File.Exists(diffInput1) &&
         diffInput2 != null && File.Exists(diffInput2) &&
         (IsCabinetFile(diffInput1) || IsCabinetFile(diffInput2)))
      {
        return .80f;
      }
      else
      {
        return 0;
      }
    }

    public bool GetDiff(string diffInput1, string diffInput2, string[] options, TextWriter diffOutput, string linePrefix, IDiffEngineFactory diffFactory)
    {
      bool difference = false;
      IComparer caseInsComp = CaseInsensitiveComparer.Default;

      // TODO: Make this faster by extracting the whole cab at once.
      // TODO: Optimize for the match case by first comparing the whole cab files.

            CabInfo cab1 = new CabInfo(diffInput1);
            CabInfo cab2 = new CabInfo(diffInput2);
      IList<CabFileInfo> cabFilesList1 = cab1.GetFiles();
            IList<CabFileInfo> cabFilesList2 = cab2.GetFiles();
            CabFileInfo[] cabFiles1 = new CabFileInfo[cabFilesList1.Count];
            CabFileInfo[] cabFiles2 = new CabFileInfo[cabFilesList2.Count];
            cabFilesList1.CopyTo(cabFiles1, 0);
            cabFilesList2.CopyTo(cabFiles2, 0);
      string[] files1 = new string[cabFiles1.Length];
      string[] files2 = new string[cabFiles2.Length];
      for(int i1 = 0; i1 < cabFiles1.Length; i1++) files1[i1] = cabFiles1[i1].Name;
      for(int i2 = 0; i2 < cabFiles2.Length; i2++) files2[i2] = cabFiles2[i2].Name;
      Array.Sort(files1, cabFiles1, caseInsComp);
      Array.Sort(files2, cabFiles2, caseInsComp);


      for(int i1 = 0, i2 = 0; i1 < files1.Length || i2 < files2.Length; )
      {
        int comp;
        if(i1 == files1.Length)
        {
          comp = 1;
        }
        else if(i2 == files2.Length)
        {
          comp = -1;
        }
        else
        {
          comp = caseInsComp.Compare(files1[i1], files2[i2]);
        }
        if(comp < 0)
        {
          diffOutput.WriteLine("{0}< {1}", linePrefix, files1[i1]);
          i1++;
          difference = true;
        }
        else if(comp > 0)
        {
          diffOutput.WriteLine("{0}> {1}", linePrefix, files2[i2]);
          i2++;
          difference = true;
        }
        else
        {
          string tempFile1 = Path.GetTempFileName();
          string tempFile2 = Path.GetTempFileName();
          cabFiles1[i1].CopyTo(tempFile1, true);
          cabFiles2[i2].CopyTo(tempFile2, true);
          IDiffEngine diffEngine = diffFactory.GetDiffEngine(tempFile1, tempFile2, options);
          StringWriter sw = new StringWriter();
          if(diffEngine.GetDiff(tempFile1, tempFile2, options, sw, linePrefix + "    ", diffFactory))
          {
            diffOutput.WriteLine("{0}{1}", linePrefix, files1[i1]);
            diffOutput.Write(sw.ToString());
            difference = true;
          }

          File.SetAttributes(tempFile1, File.GetAttributes(tempFile1) & ~FileAttributes.ReadOnly);
          File.SetAttributes(tempFile2, File.GetAttributes(tempFile2) & ~FileAttributes.ReadOnly);
          try
          {
            File.Delete(tempFile1);
            File.Delete(tempFile2);
          }
          catch(IOException)
          {
#if DEBUG
            Console.WriteLine("Could not delete temporary files {0} and {1}", tempFile1, tempFile2);
#endif
          }
          i1++;
          i2++;
        }
      }

      return difference;
    }

    public virtual IDiffEngine Clone()
    {
      return new CabDiffEngine();
    }
  }
}