From fb7643fcc28ca671d41e561de0b5f5bfdabc2754 Mon Sep 17 00:00:00 2001
From: canhlinh <canhlinh.lienson@gmail.com>
Date: Thu, 16 Mar 2023 16:35:44 +0700
Subject: [PATCH] Update mod time whenever reading a file

---
 filecache.go      |  6 +++++-
 filecache_test.go | 41 +++++++++++++++++++++++++++++++++++++++--
 2 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/filecache.go b/filecache.go
index 5c8bdaa..dbdf382 100644
--- a/filecache.go
+++ b/filecache.go
@@ -135,6 +135,10 @@ func (f *FileCache) Read(key string) (io.ReadCloser, error) {
 		return nil, err
 	}
 
+	if err := f.touch(key, time.Now()); err != nil {
+		return nil, err
+	}
+
 	file, err := os.Open(absFilePath)
 	if err != nil {
 		return nil, err
@@ -215,7 +219,7 @@ func (f *FileCache) Empty() error {
 	return nil
 }
 
-func (fc FileCache) Touch(key string, ts time.Time) error {
+func (fc FileCache) touch(key string, ts time.Time) error {
 	if ts.IsZero() {
 		ts = time.Now()
 	}
diff --git a/filecache_test.go b/filecache_test.go
index 95e0b8c..d9ceda1 100644
--- a/filecache_test.go
+++ b/filecache_test.go
@@ -65,6 +65,43 @@ func TestWrite(t *testing.T) {
 	}
 }
 
+func getModTime(path string) (time.Time, error) {
+	fs, err := os.Stat(path)
+	if err != nil {
+		return time.Time{}, err
+	}
+	return fs.ModTime(), nil
+}
+
+func TestRead(t *testing.T) {
+	fc := New(Config{TempDir: "tmp"}, nil)
+	defer fc.Empty()
+
+	if err := fc.Write("key", sampleReader("ABC")); err != nil {
+		t.Fatal(err)
+	}
+
+	if r, err := fc.Read("key"); err != nil {
+		t.Fatal(err)
+	} else {
+		var buf bytes.Buffer
+		io.Copy(&buf, r)
+		if buf.String() != "ABC" {
+			t.Fatal("file not matched")
+		}
+	}
+	mt1, err := getModTime(fc.absFilePath("key"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	time.Sleep(time.Second)
+	fc.Read("key")
+	mt2, _ := getModTime(fc.absFilePath("key"))
+	if mt2.Unix() <= mt1.Unix() {
+		t.Fatal("mod time must be changed")
+	}
+}
+
 func TestFiles(t *testing.T) {
 	fc := New(Config{TempDir: "tmp"}, nil)
 	defer fc.Empty()
@@ -205,8 +242,8 @@ func TestCleanCachedFileByLRU(t *testing.T) {
 	if err := fc.Write("key3", sampleReader(data)); err != nil {
 		t.Fatal(err)
 	}
-	fc.Touch("key1", time.Now().Add(-time.Minute))
-	fc.Touch("key3", time.Now().Add(-time.Minute))
+	fc.touch("key1", time.Now().Add(-time.Minute))
+	fc.touch("key3", time.Now().Add(-time.Minute))
 
 	if err := fc.cleanCachedFileByLRU(); err != nil {
 		t.Fatal(err)