fix IfGuard; fix dir(),base(),file_name() support Win/non-Win

vlib/os/os.v

@@ -281,15 +281,14 @@ pub fn file_ext(opath string) string {
 // If the path is empty, dir returns ".". If the path consists entirely of separators,
 // dir returns a single separator.
 // The returned path does not end in a separator unless it is the root directory.
-pub fn dir(opath string) string {
-	if opath == '' {
+pub fn dir(path string) string {
+	if path == '' {
 		return '.'
 	}
-	other_separator := if path_separator == '/' { '\\' } else { '/' }
-	path := opath.replace(other_separator, path_separator)
-	pos := path.last_index(path_separator) or { return '.' }
+	detected_path_separator := if path.contains('/') { '/' } else { '\\' }
+	pos := path.last_index(detected_path_separator) or { return '.' }
 	if pos == 0 {
-		return path_separator
+		return detected_path_separator
 	}
 	return path[..pos]
 }
@@ -298,30 +297,28 @@ pub fn dir(opath string) string {
 // Trailing path separators are removed before extracting the last element.
 // If the path is empty, base returns ".". If the path consists entirely of separators, base returns a
 // single separator.
-pub fn base(opath string) string {
-	if opath == '' {
+pub fn base(path string) string {
+	if path == '' {
 		return '.'
 	}
-	other_separator := if path_separator == '/' { '\\' } else { '/' }
-	path := opath.replace(other_separator, path_separator)
-	if path == path_separator {
-		return path_separator
+	detected_path_separator := if path.contains('/') { '/' } else { '\\' }
+	if path == detected_path_separator {
+		return detected_path_separator
 	}
-	if path.ends_with(path_separator) {
+	if path.ends_with(detected_path_separator) {
 		path2 := path[..path.len - 1]
-		pos := path2.last_index(path_separator) or { return path2.clone() }
+		pos := path2.last_index(detected_path_separator) or { return path2.clone() }
 		return path2[pos + 1..]
 	}
-	pos := path.last_index(path_separator) or { return path.clone() }
+	pos := path.last_index(detected_path_separator) or { return path.clone() }
 	return path[pos + 1..]
 }
 
 // file_name will return all characters found after the last occurrence of `path_separator`.
 // file extension is included.
-pub fn file_name(opath string) string {
-	other_separator := if path_separator == '/' { '\\' } else { '/' }
-	path := opath.replace(other_separator, path_separator)
-	return path.all_after_last(path_separator)
+pub fn file_name(path string) string {
+	detected_path_separator := if path.contains('/') { '/' } else { '\\' }
+	return path.all_after_last(detected_path_separator)
 }
 
 // split_path will split `path` into (`dir`,`filename`,`ext`).
@@ -332,30 +329,34 @@ pub fn file_name(opath string) string {
 // ```
 pub fn split_path(path string) (string, string, string) {
 	if path == '' {
-		return '', '', ''
+		return '.', '', ''
 	} else if path == '.' {
 		return '.', '', ''
 	} else if path == '..' {
 		return '..', '', ''
 	}
 
-	my_path_separator := if path.contains('/') { '/' } else { '\\' }
+	detected_path_separator := if path.contains('/') { '/' } else { '\\' }
 
-	if path == my_path_separator {
-		return my_path_separator, '', ''
+	if path == detected_path_separator {
+		return detected_path_separator, '', ''
 	}
-	if path.ends_with(my_path_separator) {
+	if path.ends_with(detected_path_separator) {
 		return path[..path.len - 1], '', ''
 	}
 	mut dir := '.'
-	if pos := path.last_index(my_path_separator) {
-		if pos == 0 {
-			dir = my_path_separator
-		} else {
-			dir = path[..pos]
-		}
+	/*
+		TODO: JS backend does not support IfGuard yet.
+	*/
+	pos := path.last_index(detected_path_separator) or { -1 }
+	if pos == -1 {
+		dir = '.'
+	} else if pos == 0 {
+		dir = detected_path_separator
+	} else {
+		dir = path[..pos]
 	}
-	file_name := path.all_after_last(my_path_separator)
+	file_name := path.all_after_last(detected_path_separator)
 	pos_ext := file_name.last_index_u8(`.`)
 	if pos_ext == -1 || pos_ext == 0 || pos_ext + 1 >= file_name.len {
 		return dir, file_name, ''

vlib/os/os_test.c.v

@@ -596,6 +596,7 @@ fn test_is_executable_writable_readable() {
 }
 
 fn test_file_ext() {
+	assert os.file_ext('') == ''
 	assert os.file_ext('file.v') == '.v'
 	assert os.file_ext('file.js.v') == '.v'
 	assert os.file_ext('file.ext1.ext2.ext3') == '.ext3'
@@ -640,48 +641,40 @@ fn test_rmdir_not_exist() ! {
 }
 
 fn test_dir() {
-	$if windows {
-		assert os.dir('\\') == '\\'
-		assert os.dir('C:\\a\\b\\c') == 'C:\\a\\b'
-		assert os.dir('C:\\a\\b\\') == 'C:\\a\\b'
-		assert os.dir('C:/a/b/c') == 'C:\\a\\b'
-		assert os.dir('C:/a/b/') == 'C:\\a\\b'
-	} $else {
-		assert os.dir('/') == '/'
-		assert os.dir('/abc') == '/'
-		assert os.dir('/var/tmp/foo') == '/var/tmp'
-		assert os.dir('/var/tmp/') == '/var/tmp'
-		assert os.dir('C:\\a\\b\\c') == 'C:/a/b'
-		assert os.dir('C:\\a\\b\\') == 'C:/a/b'
-	}
+	assert os.dir('') == '.'
+	assert os.dir('\\') == '\\'
+	assert os.dir('C:\\a\\b\\c') == 'C:\\a\\b'
+	assert os.dir('C:\\a\\b\\') == 'C:\\a\\b'
+	assert os.dir('C:/a/b/c') == 'C:/a/b'
+	assert os.dir('C:/a/b/') == 'C:/a/b'
+	assert os.dir('/') == '/'
+	assert os.dir('/abc') == '/'
+	assert os.dir('/var/tmp/foo') == '/var/tmp'
+	assert os.dir('/var/tmp/') == '/var/tmp'
 	assert os.dir('os') == '.'
 }
 
 fn test_base() {
-	$if windows {
-		assert os.base('v\\vlib\\os') == 'os'
-		assert os.base('v\\vlib\\os\\') == 'os'
-		assert os.base('v/vlib/os') == 'os'
-		assert os.base('v/vlib/os/') == 'os'
-	} $else {
-		assert os.base('v/vlib/os') == 'os'
-		assert os.base('v/vlib/os/') == 'os'
-		assert os.base('v\\vlib\\os') == 'os'
-		assert os.base('v\\vlib\\os\\') == 'os'
-	}
+	assert os.base('') == '.'
+	assert os.base('v\\vlib\\os') == 'os'
+	assert os.base('v\\vlib\\os\\') == 'os'
+	assert os.base('v/vlib/os') == 'os'
+	assert os.base('v/vlib/os/') == 'os'
+	assert os.base('v/vlib/os') == 'os'
+	assert os.base('v/vlib/os/') == 'os'
+	assert os.base('v\\vlib\\os') == 'os'
+	assert os.base('v\\vlib\\os\\') == 'os'
 	assert os.base('filename') == 'filename'
 }
 
 fn test_file_name() {
-	$if windows {
-		assert os.file_name('v\\vlib\\os\\os.v') == 'os.v'
-		assert os.file_name('v\\vlib\\os\\') == ''
-		assert os.file_name('v\\vlib\\os') == 'os'
-	} $else {
-		assert os.file_name('v/vlib/os/os.v') == 'os.v'
-		assert os.file_name('v/vlib/os/') == ''
-		assert os.file_name('v/vlib/os') == 'os'
-	}
+	assert os.file_name('') == ''
+	assert os.file_name('v\\vlib\\os\\os.v') == 'os.v'
+	assert os.file_name('v\\vlib\\os\\') == ''
+	assert os.file_name('v\\vlib\\os') == 'os'
+	assert os.file_name('v/vlib/os/os.v') == 'os.v'
+	assert os.file_name('v/vlib/os/') == ''
+	assert os.file_name('v/vlib/os') == 'os'
 	assert os.file_name('filename') == 'filename'
 }
 
@@ -691,7 +684,7 @@ fn test_split_path() {
 	mut ext := ''
 
 	dir, filename, ext = os.split_path('')
-	assert [dir, filename, ext] == ['', '', '']
+	assert [dir, filename, ext] == ['.', '', '']
 
 	dir, filename, ext = os.split_path('a')
 	assert [dir, filename, ext] == ['.', 'a', '']