
         m_output;
            private string m_errorMessage;

            public GitHistory()
            {
                // Initialize member variables.
                m_output = new List();
            }

            public string GitClient
            {
                get { return m_gitClient; }
                set { m_gitClient = value; }
            }

            public string LocalPath
            {
                get { return m_localPath; }
                set { m_localPath = value; }
            }
          
            public string VersionTag
            {
                get { return m_versionTag; }
                set { m_versionTag = value; }
            }

            [Output()]
            public int TotalChanges
            {
                get { return m_totalChanges; }
            }

            public override bool Execute()
            {
                try
                {                   
                    // Launch Git Client and wait for it to complete.
                    using (Process p = new Process())
                    {
                        p.StartInfo.FileName = m_gitClient;
                        p.StartInfo.Arguments = string.Format(@"log --pretty=oneline ""{0}..""", m_versionTag);
                        p.StartInfo.WorkingDirectory = m_localPath;
                        p.StartInfo.UseShellExecute = false;
                        p.StartInfo.RedirectStandardOutput = true;
                        p.StartInfo.RedirectStandardError = true;
                        p.OutputDataReceived += OnOutputDataReceived;
                        p.ErrorDataReceived += OnErrorDataReceived;
                        p.Start();
                        p.BeginOutputReadLine();
                        p.BeginErrorReadLine();
                        p.WaitForExit();
                    }
                  
                    // Check if the command encountered an error.
                    if (!string.IsNullOrEmpty(m_errorMessage))
                        throw new Exception(m_errorMessage);

                    // Count the number of changes returned by the query.
                    m_totalChanges = m_output.Count;
              
                    return true;
                }
                catch (Exception ex)
                {
                    // Notify about the exception.
                    m_totalChanges = -1;
                    Log.LogError(ex.Message);
                    
                    return false;
                }
            }

            private void OnOutputDataReceived(object sender, DataReceivedEventArgs e)
            {
                // Accumulate the output for processing.
                if (!string.IsNullOrEmpty(e.Data))
                    m_output.Add(e.Data);
            }
            
            private void OnErrorDataReceived(object sender, DataReceivedEventArgs e)
            {
                // Capture the encountered error.
                if (!string.IsNullOrEmpty(e.Data))
                    m_errorMessage = e.Data;
            }
        }
        ]]>