From 480521bcdccd496cbf24d8614abc880984843b46 Mon Sep 17 00:00:00 2001
From: Anirudh Oppiliappan <x@icyphox.sh>
Date: Sun, 9 Mar 2025 12:24:25 +0200
Subject: [PATCH] knotserver/git: cache just the commit hash and time

This should help alleviate the memory leakyness that was exhibited when
we stored the entire object.Commit in memory.
---
 appview/pages/templates/repo/index.html |  4 +--
 appview/pages/templates/repo/tree.html  |  4 +--
 knotserver/git/git.go                   | 37 +++++++++++++++++--------
 types/tree.go                           | 12 ++++++--
 4 files changed, 40 insertions(+), 17 deletions(-)

diff --git a/appview/pages/templates/repo/index.html b/appview/pages/templates/repo/index.html
index a7755a2..7dad806 100644
--- a/appview/pages/templates/repo/index.html
+++ b/appview/pages/templates/repo/index.html
@@ -79,7 +79,7 @@
                     </a>
 
                     <time class="text-xs text-gray-500"
-                        >{{ timeFmt .LastCommit.Author.When }}</time
+                        >{{ timeFmt .LastCommit.When }}</time
                     >
                 </div>
             </div>
@@ -104,7 +104,7 @@
                     </a>
 
                     <time class="text-xs text-gray-500"
-                        >{{ timeFmt .LastCommit.Author.When }}</time
+                        >{{ timeFmt .LastCommit.When }}</time
                     >
                 </div>
             </div>
diff --git a/appview/pages/templates/repo/tree.html b/appview/pages/templates/repo/tree.html
index 0434a80..b1c48cc 100644
--- a/appview/pages/templates/repo/tree.html
+++ b/appview/pages/templates/repo/tree.html
@@ -44,7 +44,7 @@
                     <i class="w-3 h-3 fill-current" data-lucide="folder"></i>{{ .Name }}
                 </div>
             </a>
-            <time class="text-xs text-gray-500">{{ timeFmt .LastCommit.Author.When }}</time>
+            <time class="text-xs text-gray-500">{{ timeFmt .LastCommit.When }}</time>
         </div>
     </div>
     {{ end }}
@@ -59,7 +59,7 @@
                     <i class="w-3 h-3" data-lucide="file"></i>{{ .Name }}
                 </div>
             </a>
-            <time class="text-xs text-gray-500">{{ timeFmt .LastCommit.Author.When }}</time>
+            <time class="text-xs text-gray-500">{{ timeFmt .LastCommit.When }}</time>
         </div>
     </div>
     {{ end }}
diff --git a/knotserver/git/git.go b/knotserver/git/git.go
index f165a0b..30e59d8 100644
--- a/knotserver/git/git.go
+++ b/knotserver/git/git.go
@@ -9,6 +9,7 @@ import (
 	"os/exec"
 	"path"
 	"sort"
+	"strconv"
 	"strings"
 	"sync"
 	"time"
@@ -17,6 +18,7 @@ import (
 	"github.com/go-git/go-git/v5"
 	"github.com/go-git/go-git/v5/plumbing"
 	"github.com/go-git/go-git/v5/plumbing/object"
+	"github.com/sotangled/tangled/types"
 )
 
 var (
@@ -297,16 +299,16 @@ func (g *GitRepo) WriteTar(w io.Writer, prefix string) error {
 	return nil
 }
 
-func (g *GitRepo) LastCommitForPath(path string) (*object.Commit, error) {
+func (g *GitRepo) LastCommitForPath(path string) (*types.LastCommitInfo, error) {
 	cacheKey := fmt.Sprintf("%s:%s", g.h.String(), path)
 	cacheMu.RLock()
-	if commit, found := commitCache.Get(cacheKey); found {
+	if commitInfo, found := commitCache.Get(cacheKey); found {
 		cacheMu.RUnlock()
-		return commit.(*object.Commit), nil
+		return commitInfo.(*types.LastCommitInfo), nil
 	}
 	cacheMu.RUnlock()
 
-	cmd := exec.Command("git", "-C", g.path, "log", "-1", "--format=%H", "--", path)
+	cmd := exec.Command("git", "-C", g.path, "log", "-1", "--format=%H %ct", "--", path)
 
 	var out bytes.Buffer
 	cmd.Stdout = &out
@@ -316,23 +318,36 @@ func (g *GitRepo) LastCommitForPath(path string) (*object.Commit, error) {
 		return nil, fmt.Errorf("failed to get commit hash: %w", err)
 	}
 
-	commitHash := strings.TrimSpace(out.String())
-	if commitHash == "" {
+	output := strings.TrimSpace(out.String())
+	if output == "" {
 		return nil, fmt.Errorf("no commits found for path: %s", path)
 	}
 
-	hash := plumbing.NewHash(commitHash)
+	parts := strings.SplitN(output, " ", 2)
+	if len(parts) < 2 {
+		return nil, fmt.Errorf("unexpected commit log format")
+	}
 
-	commit, err := g.r.CommitObject(hash)
+	commitHash := parts[0]
+	commitTimeUnix, err := strconv.ParseInt(parts[1], 10, 64)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("parsing commit time: %w", err)
+	}
+	commitTime := time.Unix(commitTimeUnix, 0)
+
+	hash := plumbing.NewHash(commitHash)
+
+	commitInfo := &types.LastCommitInfo{
+		Hash:    hash,
+		Message: "",
+		When:    commitTime,
 	}
 
 	cacheMu.Lock()
-	commitCache.Set(cacheKey, commit, 1)
+	commitCache.Set(cacheKey, commitInfo, 1)
 	cacheMu.Unlock()
 
-	return commit, nil
+	return commitInfo, nil
 }
 
 func newInfoWrapper(
diff --git a/types/tree.go b/types/tree.go
index 9248a0e..aedcb68 100644
--- a/types/tree.go
+++ b/types/tree.go
@@ -1,7 +1,9 @@
 package types
 
 import (
-	"github.com/go-git/go-git/v5/plumbing/object"
+	"time"
+
+	"github.com/go-git/go-git/v5/plumbing"
 )
 
 // A nicer git tree representation.
@@ -12,5 +14,11 @@ type NiceTree struct {
 	IsFile    bool   `json:"is_file"`
 	IsSubtree bool   `json:"is_subtree"`
 
-	LastCommit *object.Commit `json:"last_commit,omitempty"`
+	LastCommit *LastCommitInfo `json:"last_commit,omitempty"`
+}
+
+type LastCommitInfo struct {
+	Hash    plumbing.Hash
+	Message string
+	When    time.Time
 }
-- 
2.54.0