perf(code_analysis:config): avoid allocs

Author: Rudxain

crates/emmylua_code_analysis/src/config/pre_process.rs

@@ -1,5 +1,5 @@
 use regex::Regex;
-use std::{collections::HashSet, path::PathBuf, process::Command};
+use std::{borrow::Cow, collections::HashSet, path::PathBuf, process::Command};
 
 use crate::config::configs::{EmmyrcWorkspacePathConfig, EmmyrcWorkspacePathItem};
 
@@ -60,10 +60,9 @@ impl PreProcessContext {
     }
 
     fn pre_process_path(&self, path: &str) -> String {
-        let mut path = path.to_string();
-        path = self.replace_env_var(&path);
+        let path = self.replace_env_var(path);
         // ${workspaceFolder}  == {workspaceFolder}
-        path = path.replace("$", "");
+        let mut path = path.replace("$", ""); // ideally, this should be `Cow`
         let workspace_str = match self.workspace.to_str() {
             Some(path) => path,
             None => {
@@ -129,10 +128,10 @@ impl PreProcessContext {
     }
 
     // compact luals
-    fn replace_env_var(&self, path: &str) -> String {
+    fn replace_env_var<'a>(&self, path: &'a str) -> Cow<'a, str> {
         let re = match &self.env_var_regex {
             Some(re) => re,
-            None => return path.to_string(),
+            None => return Cow::Borrowed(path),
         };
         re.replace_all(path, |caps: &regex::Captures| {
             let key = &caps[1];
@@ -141,7 +140,6 @@ impl PreProcessContext {
                 String::new()
             })
         })
-        .to_string()
     }
 
     fn replace_placeholders(&self, input: &str, workspace_folder: &str) -> String {