From e4665f3f5c4503dd75a6c718447cc10489aebf91 Mon Sep 17 00:00:00 2001
From: Bruce Leidl <bruce@subgraph.com>
Date: Tue, 29 Jan 2019 11:42:27 -0500
Subject: [PATCH] function to test for valid names of things

---
 libcitadel/src/util.rs | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/libcitadel/src/util.rs b/libcitadel/src/util.rs
index 9518d1e..0b78efd 100644
--- a/libcitadel/src/util.rs
+++ b/libcitadel/src/util.rs
@@ -12,6 +12,28 @@ use failure::ResultExt;
 
 use crate::Result;
 
+pub fn is_valid_name(name: &str, maxsize: usize) -> bool {
+    name.len() <= maxsize &&
+        // Also false on empty string
+        is_first_char_alphabetic(name) &&
+        name.chars().all(is_alphanum_or_dash)
+}
+
+fn is_alphanum_or_dash(c: char) -> bool {
+    is_ascii(c) && (c.is_alphanumeric() || c == '-')
+}
+
+fn is_ascii(c: char) -> bool {
+    c as u32 <= 0x7F
+}
+
+pub fn is_first_char_alphabetic(s: &str) -> bool {
+    if let Some(c) = s.chars().next() {
+        return is_ascii(c) && c.is_alphabetic()
+    }
+    false
+}
+
 fn search_path(filename: &str) -> Result<PathBuf> {
     let path_var = env::var("PATH")?;
     for mut path in env::split_paths(&path_var) {