From cbfa57a9559840d44190925dd376c444fcefd1ce Mon Sep 17 00:00:00 2001
From: Sergey Lyubka <cpq@users.noreply.github.com>
Date: Thu, 1 Feb 2024 17:45:20 +0000
Subject: [PATCH] Add helper mg_fs_ls()

---
 mongoose.c | 20 ++++++++++++++++++++
 mongoose.h |  1 +
 src/fs.c   | 20 ++++++++++++++++++++
 src/fs.h   |  1 +
 4 files changed, 42 insertions(+)

diff --git a/mongoose.c b/mongoose.c
index 18aa613841..15ade247d1 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -1666,6 +1666,26 @@ bool mg_file_printf(struct mg_fs *fs, const char *path, const char *fmt, ...) {
   return result;
 }
 
+// This helper function allows to scan a filesystem in a sequential way,
+// without using callback function:
+//      char buf[100] = "";
+//      while (mg_fs_ls(&mg_fs_posix, "./", buf, sizeof(buf))) {
+//        ...
+static void mg_fs_ls_fn(const char *filename, void *param) {
+  struct mg_str *s = (struct mg_str *) param;
+  if (s->ptr[0] == '\0') {
+    mg_snprintf((char *) s->ptr, s->len, "%s", filename);
+  } else if (strcmp(s->ptr, filename) == 0) {
+    ((char *) s->ptr)[0] = '\0';  // Fetch next file
+  }
+}
+
+bool mg_fs_ls(struct mg_fs *fs, const char *path, char *buf, size_t len) {
+  struct mg_str s = {buf, len};
+  fs->ls(path, mg_fs_ls_fn, &s);
+  return buf[0] != '\0';
+}
+
 #ifdef MG_ENABLE_LINES
 #line 1 "src/fs_fat.c"
 #endif
diff --git a/mongoose.h b/mongoose.h
index f40c0023b2..7e708e371f 100644
--- a/mongoose.h
+++ b/mongoose.h
@@ -1025,6 +1025,7 @@ struct mg_fd {
 
 struct mg_fd *mg_fs_open(struct mg_fs *fs, const char *path, int flags);
 void mg_fs_close(struct mg_fd *fd);
+bool mg_fs_ls(struct mg_fs *fs, const char *path, char *buf, size_t len);
 char *mg_file_read(struct mg_fs *fs, const char *path, size_t *size);
 bool mg_file_write(struct mg_fs *fs, const char *path, const void *, size_t);
 bool mg_file_printf(struct mg_fs *fs, const char *path, const char *fmt, ...);
diff --git a/src/fs.c b/src/fs.c
index 00eeb0edac..19681079a9 100644
--- a/src/fs.c
+++ b/src/fs.c
@@ -72,3 +72,23 @@ bool mg_file_printf(struct mg_fs *fs, const char *path, const char *fmt, ...) {
   free(data);
   return result;
 }
+
+// This helper function allows to scan a filesystem in a sequential way,
+// without using callback function:
+//      char buf[100] = "";
+//      while (mg_fs_ls(&mg_fs_posix, "./", buf, sizeof(buf))) {
+//        ...
+static void mg_fs_ls_fn(const char *filename, void *param) {
+  struct mg_str *s = (struct mg_str *) param;
+  if (s->ptr[0] == '\0') {
+    mg_snprintf((char *) s->ptr, s->len, "%s", filename);
+  } else if (strcmp(s->ptr, filename) == 0) {
+    ((char *) s->ptr)[0] = '\0';  // Fetch next file
+  }
+}
+
+bool mg_fs_ls(struct mg_fs *fs, const char *path, char *buf, size_t len) {
+  struct mg_str s = {buf, len};
+  fs->ls(path, mg_fs_ls_fn, &s);
+  return buf[0] != '\0';
+}
diff --git a/src/fs.h b/src/fs.h
index a5fa31d906..b09e9bdaae 100644
--- a/src/fs.h
+++ b/src/fs.h
@@ -39,6 +39,7 @@ struct mg_fd {
 
 struct mg_fd *mg_fs_open(struct mg_fs *fs, const char *path, int flags);
 void mg_fs_close(struct mg_fd *fd);
+bool mg_fs_ls(struct mg_fs *fs, const char *path, char *buf, size_t len);
 char *mg_file_read(struct mg_fs *fs, const char *path, size_t *size);
 bool mg_file_write(struct mg_fs *fs, const char *path, const void *, size_t);
 bool mg_file_printf(struct mg_fs *fs, const char *path, const char *fmt, ...);