From 206c1f4ca1e7455aec6e4c5fd0b50053c8d79962 Mon Sep 17 00:00:00 2001
From: Delyan Angelov <delian66@gmail.com>
Date: Sun, 5 Apr 2020 16:56:54 +0300
Subject: [PATCH] os: implement os.is_writable_folder/1

---
 vlib/os/os.v      | 17 +++++++++++++++++
 vlib/os/os_test.v |  9 +++++++++
 2 files changed, 26 insertions(+)

diff --git a/vlib/os/os.v b/vlib/os/os.v
index 42733d9e99..ce678f68b8 100644
--- a/vlib/os/os.v
+++ b/vlib/os/os.v
@@ -543,6 +543,23 @@ pub fn is_executable(path string) bool {
   return C.access(path.str, X_OK) != -1
 }
 
+// `is_writable_folder` - `folder` exists and is writable to the process
+pub fn is_writable_folder(folder string) ?bool {
+	if !os.exists(folder) {
+		return error('`$folder` does not exist')
+	}
+	if !os.is_dir(folder) {
+		return error('`folder` is not a folder')
+	}
+	tmp_perm_check := os.join_path(folder, 'tmp_perm_check')
+	f := os.open_file(tmp_perm_check, 'w+', 0o700) or {
+		return error('cannot write to folder `$folder`: $err')
+	}
+	f.close()
+	os.rm(tmp_perm_check)
+	return true
+}
+
 // `is_writable` returns `true` if `path` is writable.
 pub fn is_writable(path string) bool {
   $if windows {
diff --git a/vlib/os/os_test.v b/vlib/os/os_test.v
index 14442fbc79..ec32546bc0 100644
--- a/vlib/os/os_test.v
+++ b/vlib/os/os_test.v
@@ -208,6 +208,15 @@ fn test_tmpdir() {
 	os.rm(tfile)
 }
 
+fn test_is_writable_folder() {
+	tmp := os.temp_dir()
+	f := os.is_writable_folder(tmp) or {
+		eprintln('err: $err')
+		assert false
+	}
+	assert f
+}
+
 fn test_make_symlink_check_is_link_and_remove_symlink() {
 	$if windows {
 		// TODO