From 6500282575bba24596030af15311f15c61874f02 Mon Sep 17 00:00:00 2001
From: Jan De Dobbeleer <jan.de.dobbeleer@gmail.com>
Date: Mon, 4 Mar 2024 07:57:48 +0100
Subject: [PATCH] feat(env): cache filesystem for fast lookup

---
 src/platform/shell.go | 49 ++++++++++++++++++++++++-------------------
 1 file changed, 27 insertions(+), 22 deletions(-)

diff --git a/src/platform/shell.go b/src/platform/shell.go
index f70a801a..81941794 100644
--- a/src/platform/shell.go
+++ b/src/platform/shell.go
@@ -281,6 +281,8 @@ type Shell struct {
 	networks  []*Connection
 
 	sync.RWMutex
+
+	lsDirMap ConcurrentMap
 }
 
 func (env *Shell) Init() {
@@ -430,20 +432,37 @@ func (env *Shell) Pwd() string {
 }
 
 func (env *Shell) HasFiles(pattern string) bool {
+	return env.HasFilesInDir(env.Pwd(), pattern)
+}
+
+func (env *Shell) HasFilesInDir(dir, pattern string) bool {
 	defer env.Trace(time.Now(), pattern)
 
-	cwd := env.Pwd()
-	fileSystem := os.DirFS(cwd)
+	fileSystem := os.DirFS(dir)
+	var dirEntries []fs.DirEntry
 
-	matches, err := fs.ReadDir(fileSystem, ".")
-	if err != nil {
-		env.Error(err)
-		env.Debug("false")
-		return false
+	if files, OK := env.lsDirMap.Get(dir); OK {
+		dirEntries, _ = files.([]fs.DirEntry)
+	}
+
+	if len(dirEntries) == 0 {
+		var err error
+		dirEntries, err = fs.ReadDir(fileSystem, ".")
+		if err != nil {
+			env.Error(err)
+			env.Debug("false")
+			return false
+		}
+
+		env.lsDirMap.Set(dir, dirEntries)
 	}
 
 	pattern = strings.ToLower(pattern)
-	for _, match := range matches {
+
+	env.RWMutex.RLock()
+	defer env.RWMutex.RUnlock()
+
+	for _, match := range dirEntries {
 		if match.IsDir() {
 			continue
 		}
@@ -465,20 +484,6 @@ func (env *Shell) HasFiles(pattern string) bool {
 	return false
 }
 
-func (env *Shell) HasFilesInDir(dir, pattern string) bool {
-	defer env.Trace(time.Now(), pattern)
-	fileSystem := os.DirFS(dir)
-	matches, err := fs.Glob(fileSystem, pattern)
-	if err != nil {
-		env.Error(err)
-		env.Debug("false")
-		return false
-	}
-	hasFilesInDir := len(matches) > 0
-	env.DebugF("%t", hasFilesInDir)
-	return hasFilesInDir
-}
-
 func (env *Shell) HasFileInParentDirs(pattern string, depth uint) bool {
 	defer env.Trace(time.Now(), pattern, fmt.Sprint(depth))
 	currentFolder := env.Pwd()