From 0c40e6d5d821633f673968f52caea392d0138367 Mon Sep 17 00:00:00 2001
From: Philippe Miossec <pmiossec@gmail.com>
Date: Thu, 7 Sep 2023 12:11:29 +0200
Subject: [PATCH] Rebase: improve perfs when displaying list of commits

by retrieving all the commits data with only one `git log` call
instead of one by commit.
It is possible as when rebasing, all the commits belong to the same branch.

Kept a fall back to previous way to retrieve commit data for 1 commit
if commit is not in the one loaded.

Results with 7448 commits rebased: 2s instead of 4m50 previously

Fixes #10698 and #11196
---
 GitCommands/Git/GitModule.cs  | 65 +++++++++++++++++++----------------
 GitCommands/RevisionReader.cs | 24 +++++++++++++
 2 files changed, 59 insertions(+), 30 deletions(-)

diff --git a/GitCommands/Git/GitModule.cs b/GitCommands/Git/GitModule.cs
index 51edba204b6..4e3b6af12f8 100644
--- a/GitCommands/Git/GitModule.cs
+++ b/GitCommands/Git/GitModule.cs
@@ -2143,42 +2143,47 @@ public IReadOnlyList<PatchFile> GetInteractiveRebasePatchFiles()
 
             List<PatchFile> patchFiles = new();
 
-            if (todoCommits is not null)
+            if (todoCommits is null)
             {
-                string commentChar = EffectiveConfigFile.GetString("core.commentChar", "#");
+                return patchFiles;
+            }
 
-                string? currentCommitShortHash = File.Exists(CurrentFilePath) ? File.ReadAllText(CurrentFilePath).Trim() : null;
-                var isCurrentFound = false;
-                foreach (string todoCommit in todoCommits)
-                {
-                    if (todoCommit.StartsWith(commentChar))
-                    {
-                        continue;
-                    }
+            string commentChar = EffectiveConfigFile.GetString("core.commentChar", "#");
 
-                    string[] parts = todoCommit.Split(Delimiters.Space);
+            string[][] todoCommitsInfos = todoCommits.Where(l => !l.StartsWith(commentChar))
+                .Select(l => l.Split(Delimiters.Space))
+                .Where(p => p.Length >= 3)
+                .ToArray();
 
-                    if (parts.Length < 3)
-                    {
-                        continue;
-                    }
+            string? currentCommitShortHash = File.Exists(CurrentFilePath) ? File.ReadAllText(CurrentFilePath).Trim() : null;
+            var isCurrentFound = false;
 
-                    string commitHash = parts[1];
-                    CommitData? data = _commitDataManager.GetCommitData(commitHash, out var error);
-                    var isApplying = currentCommitShortHash is not null && commitHash.StartsWith(currentCommitShortHash);
-                    isCurrentFound |= isApplying;
+            RevisionReader reader = new(this, hasReflogSelector: false);
+            CancellationTokenSource cts = new(2 * 60_000);
+            Dictionary<string, GitRevision> rebasedCommitsRevisions =
+                reader.GetRevisionsFromRange(todoCommitsInfos[0][1], todoCommitsInfos[^1][1], cts.Token)
+                .ToDictionary(r => r.Guid, r => r);
 
-                    patchFiles.Add(new PatchFile
-                    {
-                        Author = error ?? data?.Author,
-                        ObjectId = data?.ObjectId,
-                        Subject = error ?? data?.Body,
-                        Action = parts[0],
-                        Date = error ?? data?.CommitDate.LocalDateTime.ToString(),
-                        IsNext = isApplying,
-                        IsApplied = !isCurrentFound,
-                    });
-                }
+            foreach (string[] parts in todoCommitsInfos)
+            {
+                string commitHash = parts[1];
+                CommitData? data = rebasedCommitsRevisions.TryGetValue(commitHash, out GitRevision commitRevision)
+                    ? _commitDataManager.CreateFromRevision(commitRevision, null)
+                    : _commitDataManager.GetCommitData(commitHash, out var _);
+
+                var isApplying = currentCommitShortHash is not null && commitHash.StartsWith(currentCommitShortHash);
+                isCurrentFound |= isApplying;
+
+                patchFiles.Add(new PatchFile
+                {
+                    Author = data?.Author,
+                    ObjectId = data?.ObjectId,
+                    Subject = data?.Body,
+                    Action = parts[0],
+                    Date = data?.CommitDate.LocalDateTime.ToString(),
+                    IsNext = isApplying,
+                    IsApplied = !isCurrentFound,
+                });
             }
 
             return patchFiles;
diff --git a/GitCommands/RevisionReader.cs b/GitCommands/RevisionReader.cs
index 57216925bb4..1cb6866334f 100644
--- a/GitCommands/RevisionReader.cs
+++ b/GitCommands/RevisionReader.cs
@@ -97,6 +97,30 @@ public IReadOnlyCollection<GitRevision> GetRevisionsFromList(IList<ObjectId> unt
             return GetRevisionsFromArguments(arguments, cancellationToken);
         }
 
+        /// <summary>
+        /// Get the GitRevisions for all commits between 2 commits (boundaries included).
+        /// </summary>
+        /// <param name="olderCommitId">older commit Id.</param>
+        /// <param name="newerCommitId">newer commit Id.</param>
+        /// <param name="cancellationToken">Cancellation cancellationToken.</param>
+        /// <returns>List with GitRevisions.</returns>
+        public IReadOnlyCollection<GitRevision> GetRevisionsFromRange(string olderCommitId, string newerCommitId, CancellationToken cancellationToken)
+        {
+            if (string.IsNullOrWhiteSpace(olderCommitId) || string.IsNullOrWhiteSpace(newerCommitId))
+            {
+                return Array.Empty<GitRevision>();
+            }
+
+            GitArgumentBuilder arguments = new("log")
+                {
+                    "-z",
+                    $"--pretty=format:\"{FullFormat}\"",
+                    $"{olderCommitId}~..{newerCommitId}"
+                };
+
+            return GetRevisionsFromArguments(arguments, cancellationToken);
+        }
+
         /// <summary>
         /// Get the GitRevisions for Git argument.
         /// </summary>