From fef447a659cb069f178ac4fce2ffec9175ae8223 Mon Sep 17 00:00:00 2001
From: Jonathan Turner <jonathan.d.turner@gmail.com>
Date: Mon, 19 Aug 2019 19:29:27 +1200
Subject: [PATCH] Fix shell-ring to rotate as expected

---
 src/commands/shells.rs     |  4 +--
 src/parser/deserializer.rs |  2 --
 src/prelude.rs             |  2 +-
 src/shell/shell_manager.rs | 53 +++++++++++++++++++-------------------
 4 files changed, 28 insertions(+), 33 deletions(-)

diff --git a/src/commands/shells.rs b/src/commands/shells.rs
index 0c59822965..6caf53a240 100644
--- a/src/commands/shells.rs
+++ b/src/commands/shells.rs
@@ -6,12 +6,10 @@ pub fn shells(args: CommandArgs, _registry: &CommandRegistry) -> Result<OutputSt
     let mut shells_out = VecDeque::new();
     let span = args.call_info.name_span;
 
-    let shells_len = args.shell_manager.shells.lock().unwrap().len();
-
     for (index, shell) in args.shell_manager.shells.lock().unwrap().iter().enumerate() {
         let mut dict = TaggedDictBuilder::new(Tag::unknown_origin(span));
 
-        if index == (shells_len - 1) {
+        if index == args.shell_manager.current_shell {
             dict.insert(" ", "X".to_string());
         } else {
             dict.insert(" ", " ".to_string());
diff --git a/src/parser/deserializer.rs b/src/parser/deserializer.rs
index fe0289aa09..b2cc00ac62 100644
--- a/src/parser/deserializer.rs
+++ b/src/parser/deserializer.rs
@@ -1,5 +1,3 @@
-use crate::commands::command::EvaluatedCommandArgs;
-use crate::parser::registry::EvaluatedArgs;
 use crate::prelude::*;
 use log::trace;
 use serde::{de, forward_to_deserialize_any};
diff --git a/src/prelude.rs b/src/prelude.rs
index eec943a99c..9e1f7322f8 100644
--- a/src/prelude.rs
+++ b/src/prelude.rs
@@ -41,7 +41,7 @@ crate use crate::context::CommandRegistry;
 crate use crate::context::{Context, SpanSource};
 crate use crate::env::host::handle_unexpected;
 crate use crate::env::Host;
-crate use crate::errors::{ShellError, ShellErrorUtils};
+crate use crate::errors::ShellError;
 crate use crate::object::base as value;
 crate use crate::object::meta::{Tag, Tagged, TaggedItem};
 crate use crate::object::types::ExtractType;
diff --git a/src/shell/shell_manager.rs b/src/shell/shell_manager.rs
index bce931c513..18ccd94b91 100644
--- a/src/shell/shell_manager.rs
+++ b/src/shell/shell_manager.rs
@@ -9,12 +9,14 @@ use std::sync::{Arc, Mutex};
 
 #[derive(Clone, Debug)]
 pub struct ShellManager {
+    crate current_shell: usize,
     crate shells: Arc<Mutex<Vec<Box<dyn Shell + Send>>>>,
 }
 
 impl ShellManager {
     pub fn basic(commands: CommandRegistry) -> Result<ShellManager, Box<dyn Error>> {
         Ok(ShellManager {
+            current_shell: 0,
             shells: Arc::new(Mutex::new(vec![Box::new(FilesystemShell::basic(
                 commands,
             )?)])),
@@ -23,11 +25,17 @@ impl ShellManager {
 
     pub fn push(&mut self, shell: Box<dyn Shell + Send>) {
         self.shells.lock().unwrap().push(shell);
+        self.current_shell = self.shells.lock().unwrap().len() - 1;
         self.set_path(self.path());
     }
 
     pub fn pop(&mut self) {
         self.shells.lock().unwrap().pop();
+        let new_len = self.shells.lock().unwrap().len();
+        if new_len > 0 {
+            self.current_shell = new_len - 1;
+            self.set_path(self.path());
+        }
     }
 
     pub fn is_empty(&self) -> bool {
@@ -35,16 +43,11 @@ impl ShellManager {
     }
 
     pub fn path(&self) -> String {
-        self.shells.lock().unwrap().last().unwrap().path()
+        self.shells.lock().unwrap()[self.current_shell].path()
     }
 
     pub fn set_path(&mut self, path: String) {
-        self.shells
-            .lock()
-            .unwrap()
-            .last_mut()
-            .unwrap()
-            .set_path(path)
+        self.shells.lock().unwrap()[self.current_shell].set_path(path)
     }
 
     pub fn complete(
@@ -53,37 +56,33 @@ impl ShellManager {
         pos: usize,
         ctx: &rustyline::Context<'_>,
     ) -> Result<(usize, Vec<rustyline::completion::Pair>), rustyline::error::ReadlineError> {
-        self.shells
-            .lock()
-            .unwrap()
-            .last()
-            .unwrap()
-            .complete(line, pos, ctx)
+        self.shells.lock().unwrap()[self.current_shell].complete(line, pos, ctx)
     }
 
     pub fn hint(&self, line: &str, pos: usize, ctx: &rustyline::Context<'_>) -> Option<String> {
-        self.shells
-            .lock()
-            .unwrap()
-            .last()
-            .unwrap()
-            .hint(line, pos, ctx)
+        self.shells.lock().unwrap()[self.current_shell].hint(line, pos, ctx)
     }
 
     pub fn next(&mut self) {
         {
-            let mut x = self.shells.lock().unwrap();
-            let shell = x.remove(0);
-            x.push(shell);
+            let shell_len = self.shells.lock().unwrap().len();
+            if self.current_shell == (shell_len - 1) {
+                self.current_shell = 0;
+            } else {
+                self.current_shell += 1;
+            }
         }
         self.set_path(self.path());
     }
 
     pub fn prev(&mut self) {
         {
-            let mut x = self.shells.lock().unwrap();
-            let shell = x.pop().unwrap();
-            x.insert(0, shell);
+            let shell_len = self.shells.lock().unwrap().len();
+            if self.current_shell == 0 {
+                self.current_shell = shell_len - 1;
+            } else {
+                self.current_shell -= 1;
+            }
         }
         self.set_path(self.path());
     }
@@ -91,11 +90,11 @@ impl ShellManager {
     pub fn ls(&self, args: EvaluatedWholeStreamCommandArgs) -> Result<OutputStream, ShellError> {
         let env = self.shells.lock().unwrap();
 
-        env.last().unwrap().ls(args)
+        env[self.current_shell].ls(args)
     }
     pub fn cd(&self, args: EvaluatedWholeStreamCommandArgs) -> Result<OutputStream, ShellError> {
         let env = self.shells.lock().unwrap();
 
-        env.last().unwrap().cd(args)
+        env[self.current_shell].cd(args)
     }
 }