Merge pull request #246: Update Git to include prefetch logic

See microsoft/git#223 for details.

Resolves #141.

* [x] Call `git gvfs-helper prefetch` in `scalar maintenance fetch-commits-and-trees`
* [x] Delete existing prefetch logic in the C# layer.

Directory.Build.props

@@ -36,7 +36,7 @@
 
     <!-- Version information -->
     <ScalarVersion>0.2.173.2</ScalarVersion>
-    <GitPackageVersion>2.20191211.2</GitPackageVersion>
+    <GitPackageVersion>2.20191217.2</GitPackageVersion>
     <WatchmanPackageUrl>https://github.com/facebook/watchman/suites/307436006/artifacts/304557</WatchmanPackageUrl>
     <GcmCoreOSXPackageUrl>https://github.com/microsoft/Git-Credential-Manager-Core/releases/download/v2.0.79-beta/gcmcore-osx-2.0.79.64449.pkg</GcmCoreOSXPackageUrl>
 

Scalar.Common/Git/GitProcess.cs

@@ -449,6 +449,11 @@ public Result GvfsHelperDownloadCommit(string commitId)
                 });
         }
 
+        public Result GvfsHelperPrefetch()
+        {
+            return this.InvokeGitInWorkingDirectoryRoot("gvfs-helper prefetch", fetchMissingObjects: false);
+        }
+
         public Result Status(bool allowObjectDownloads, bool useStatusCache, bool showUntracked = false)
         {
             string command = "status";

Scalar.Common/Http/GitObjectsHttpRequestor.cs

@@ -4,7 +4,6 @@
 using System.Collections.Generic;
 using System.Net;
 using System.Net.Http;
-using System.Net.Http.Headers;
 using System.Threading;
 
 namespace Scalar.Common.Http
@@ -58,92 +57,6 @@ public virtual GitRefs QueryInfoRefs(string branch)
             return output.Result;
         }
 
-        public virtual RetryWrapper<GitObjectTaskResult>.InvocationResult TrySendProtocolRequest(
-            long requestId,
-            Func<int, GitEndPointResponseData, RetryWrapper<GitObjectTaskResult>.CallbackResult> onSuccess,
-            Action<RetryWrapper<GitObjectTaskResult>.ErrorEventArgs> onFailure,
-            HttpMethod method,
-            Uri endPoint,
-            CancellationToken cancellationToken,
-            string requestBody = null,
-            MediaTypeWithQualityHeaderValue acceptType = null,
-            bool retryOnFailure = true)
-        {
-            return this.TrySendProtocolRequest(
-                requestId,
-                onSuccess,
-                onFailure,
-                method,
-                endPoint,
-                cancellationToken,
-                () => requestBody,
-                acceptType,
-                retryOnFailure);
-        }
-
-        public virtual RetryWrapper<GitObjectTaskResult>.InvocationResult TrySendProtocolRequest(
-            long requestId,
-            Func<int, GitEndPointResponseData, RetryWrapper<GitObjectTaskResult>.CallbackResult> onSuccess,
-            Action<RetryWrapper<GitObjectTaskResult>.ErrorEventArgs> onFailure,
-            HttpMethod method,
-            Uri endPoint,
-            CancellationToken cancellationToken,
-            Func<string> requestBodyGenerator,
-            MediaTypeWithQualityHeaderValue acceptType = null,
-            bool retryOnFailure = true)
-        {
-            return this.TrySendProtocolRequest(
-                requestId,
-                onSuccess,
-                onFailure,
-                method,
-                () => endPoint,
-                requestBodyGenerator,
-                cancellationToken,
-                acceptType,
-                retryOnFailure);
-        }
-
-        public virtual RetryWrapper<GitObjectTaskResult>.InvocationResult TrySendProtocolRequest(
-            long requestId,
-            Func<int, GitEndPointResponseData, RetryWrapper<GitObjectTaskResult>.CallbackResult> onSuccess,
-            Action<RetryWrapper<GitObjectTaskResult>.ErrorEventArgs> onFailure,
-            HttpMethod method,
-            Func<Uri> endPointGenerator,
-            Func<string> requestBodyGenerator,
-            CancellationToken cancellationToken,
-            MediaTypeWithQualityHeaderValue acceptType = null,
-            bool retryOnFailure = true)
-        {
-            RetryWrapper<GitObjectTaskResult> retrier = new RetryWrapper<GitObjectTaskResult>(
-                retryOnFailure ? this.RetryConfig.MaxAttempts : 1,
-                cancellationToken);
-            if (onFailure != null)
-            {
-                retrier.OnFailure += onFailure;
-            }
-
-            return retrier.Invoke(
-                tryCount =>
-                {
-                    using (GitEndPointResponseData response = this.SendRequest(
-                        requestId,
-                        endPointGenerator(),
-                        method,
-                        requestBodyGenerator(),
-                        cancellationToken,
-                        acceptType))
-                    {
-                        if (response.HasErrors)
-                        {
-                            return new RetryWrapper<GitObjectTaskResult>.CallbackResult(response.Error, response.ShouldRetry, new GitObjectTaskResult(response.StatusCode));
-                        }
-
-                        return onSuccess(tryCount, response);
-                    }
-                });
-        }
-
         public class GitObjectTaskResult
         {
             public GitObjectTaskResult(bool success)

Scalar.Common/Maintenance/FetchCommitsAndTreesStep.cs

@@ -35,8 +35,6 @@ public bool TryFetchCommitsAndTrees(out string error, GitProcess gitProcess = nu
                 gitProcess = new GitProcess(this.Context.Enlistment);
             }
 
-            List<string> packIndexes;
-
             // We take our own lock here to keep background and foreground fetches
             // (i.e. a user running 'scalar maintenance --fetch-commits-and-trees')
             // from running at the same time.
@@ -46,25 +44,22 @@ public bool TryFetchCommitsAndTrees(out string error, GitProcess gitProcess = nu
                 Path.Combine(this.Context.Enlistment.GitPackRoot, FetchCommitsAndTreesLock)))
             {
                 WaitUntilLockIsAcquired(this.Context.Tracer, fetchLock);
-                long maxGoodTimeStamp;
 
                 this.GitObjects.DeleteStaleTempPrefetchPackAndIdxs();
                 this.GitObjects.DeleteTemporaryFiles();
 
-                if (!this.TryGetMaxGoodPrefetchPackTimestamp(out maxGoodTimeStamp, out error))
-                {
-                    return false;
-                }
+                GitProcess.Result result = gitProcess.GvfsHelperPrefetch();
 
-                if (!this.GitObjects.TryDownloadPrefetchPacks(gitProcess, maxGoodTimeStamp, out packIndexes))
+                if (result.ExitCodeIsFailure)
                 {
-                    error = "Failed to download prefetch packs";
+                    error = result.Errors;
                     return false;
                 }
 
                 this.UpdateKeepPacks();
             }
 
+            error = null;
             return true;
         }
 

Scalar.Common/Paths.Shared.cs

@@ -1,51 +1,9 @@
-using System;
 using System.IO;
-using System.Linq;
 
 namespace Scalar.Common
 {
     public static class Paths
     {
-        public static string GetRoot(string startingDirectory, string rootName)
-        {
-            startingDirectory = startingDirectory.TrimEnd(Path.DirectorySeparatorChar);
-            DirectoryInfo dirInfo;
-
-            try
-            {
-                dirInfo = new DirectoryInfo(startingDirectory);
-            }
-            catch (Exception)
-            {
-                return null;
-            }
-
-            while (dirInfo != null)
-            {
-                if (dirInfo.Exists)
-                {
-                    DirectoryInfo[] dotScalarDirs = new DirectoryInfo[0];
-
-                    try
-                    {
-                        dotScalarDirs = dirInfo.GetDirectories(rootName);
-                    }
-                    catch (IOException)
-                    {
-                    }
-
-                    if (dotScalarDirs.Count() == 1)
-                    {
-                        return dirInfo.FullName;
-                    }
-                }
-
-                dirInfo = dirInfo.Parent;
-            }
-
-            return null;
-        }
-
         public static string ConvertPathToGitFormat(string path)
         {
             return path.Replace(Path.DirectorySeparatorChar, ScalarConstants.GitPathSeparator);