From b5923d0cd3b822c381f22bc9043be76dd5527828 Mon Sep 17 00:00:00 2001
From: Sam Hedin <sam.hedin@gmail.com>
Date: Sun, 14 Jun 2020 14:56:11 +0200
Subject: [PATCH] Performance concerns

---
 .../src/env/directory_specific_environment.rs | 48 +++++++++----------
 1 file changed, 23 insertions(+), 25 deletions(-)

diff --git a/crates/nu-cli/src/env/directory_specific_environment.rs b/crates/nu-cli/src/env/directory_specific_environment.rs
index 32e86f1041..5e7cc6638f 100644
--- a/crates/nu-cli/src/env/directory_specific_environment.rs
+++ b/crates/nu-cli/src/env/directory_specific_environment.rs
@@ -84,7 +84,7 @@ impl DirectorySpecificEnvironment {
         while let Some(wdir) = working_dir {
             if self.allowed_directories.contains(wdir) {
                 let toml_doc = std::fs::read_to_string(wdir.join(".nu-env").as_path())
-                    .unwrap_or_else(|_| r#"[env]"#.to_string())
+                    .unwrap_or_else(|_| "[env]".to_string())
                     .parse::<toml::Value>()?;
 
                 toml_doc
@@ -101,12 +101,13 @@ impl DirectorySpecificEnvironment {
                             if let Some(val) = std::env::var_os(k) {
                                 self.overwritten_env_values
                                     .entry(wdir.to_path_buf())
-                                    .or_insert(IndexMap::new())
+                                    .or_insert_with(|| IndexMap::new())
                                     .insert(k.clone(), val);
-                            } else { //Otherwise, we just track that we added it here
+                            } else {
+                                //Otherwise, we just track that we added it here
                                 self.added_env_vars
                                     .entry(wdir.to_path_buf())
-                                    .or_insert(IndexSet::new())
+                                    .or_insert_with(|| IndexSet::new())
                                     .insert(k.clone());
                             }
                         }
@@ -126,29 +127,26 @@ impl DirectorySpecificEnvironment {
     pub fn env_vars_to_delete(&mut self) -> Result<Vec<String>> {
         let current_dir = std::env::current_dir()?;
 
-        let mut new_added_env_vars: IndexMap<PathBuf, IndexSet<String>> = IndexMap::new();
-        //Gather up all environment variables that should be deleted.
-        //If we are not in a directory or one of its subdirectories, mark the env_vals it maps to for removal.
-        let vars_to_delete = self.added_env_vars.iter().fold(
-            Vec::new(),
-            |mut vars_to_delete, (directory, env_vars)| {
-                let mut working_dir = Some(current_dir.as_path());
+        let mut new_added_env_vars = IndexMap::new();
+        let mut working_dir = Some(current_dir.as_path());
 
-                while let Some(wdir) = working_dir {
-                    if wdir == directory {
-                        if let Some(vars_added_by_this_directory) = self.added_env_vars.get(wdir) { //If we are still in a directory, we should continue to track the vars it added.
-                            new_added_env_vars.insert(wdir.to_path_buf(), vars_added_by_this_directory.clone());
-                        }
-                        return vars_to_delete;
-                    } else {
-                        working_dir = working_dir.expect("Root directory has no parent").parent();
-                    }
+        while let Some(wdir) = working_dir {
+            if let Some(vars_added_by_this_directory) = self.added_env_vars.get(wdir) {
+                //If we are still in a directory, we should continue to track the vars it added.
+                new_added_env_vars.insert(wdir.to_path_buf(), vars_added_by_this_directory.clone());
+            }
+            working_dir = working_dir.expect("Root directory has no parent").parent();
+        }
+
+        //Gather up all environment variables that should be deleted.
+        let mut vars_to_delete = vec![];
+        self.added_env_vars.iter().for_each(|(dir, added_keys)| {
+            if !new_added_env_vars.contains_key(dir) {
+                for k in added_keys {
+                    vars_to_delete.push(k.clone());
                 }
-                //only delete vars from directories we are not in
-                vars_to_delete.extend(env_vars.clone());
-                vars_to_delete
-            },
-        );
+            }
+        });
         self.added_env_vars = new_added_env_vars;
         Ok(vars_to_delete)
     }