sorry about monster commit

wlx-overlay-s/src/gui/panel/helper.rs

@@ -0,0 +1,53 @@
+use regex::Regex;
+use std::{
+    io::{BufRead, BufReader, Read},
+    sync::LazyLock,
+};
+
+static ENV_VAR_REGEX: LazyLock<Regex> = LazyLock::new(|| {
+    Regex::new(r"\$\{([A-Z_][A-Z0-9_]*)}|\$([A-Z_][A-Z0-9_]*)").unwrap() // want panic
+});
+
+pub(super) fn expand_env_vars(template: &str) -> String {
+    ENV_VAR_REGEX
+        .replace_all(template, |caps: &regex::Captures| {
+            let var_name = caps.get(1).or(caps.get(2)).unwrap().as_str();
+            std::env::var(var_name)
+                .inspect_err(|e| log::warn!("Unable to substitute env var {var_name}: {e:?}"))
+                .unwrap_or_default()
+        })
+        .into_owned()
+}
+
+pub(super) fn read_label_from_pipe<R>(
+    path: &str,
+    reader: &mut BufReader<R>,
+    carry_over: &mut Option<String>,
+) -> Option<String>
+where
+    R: Read + Sized,
+{
+    let mut prev = String::new();
+    let mut cur = String::new();
+
+    for r in reader.lines() {
+        match r {
+            Ok(line) => {
+                prev = cur;
+                cur = carry_over.take().map(|s| s + &line).unwrap_or(line);
+            }
+            Err(e) => {
+                log::warn!("pipe read error on {path}: {e:?}");
+                return None;
+            }
+        }
+    }
+
+    carry_over.replace(cur);
+
+    if prev.len() > 0 {
+        Some(prev)
+    } else {
+        None
+    }
+}