make error model more autonomous

4 files changed, 40 insertions, 47 deletions

diff --git a/src/common/errors.rs b/src/common/errors.rs
index 9801428c..d0b748ab 100644
--- a/src/common/errors.rs
+++ b/src/common/errors.rs
@@ -1,7 +1,7 @@
 //! Error context system based on a thread-local representation of the call stack, itself based on
 //! the instructions that are sent between threads.
 
-use super::{AppInstruction, OPENCALLS};
+use super::{AppInstruction, ASYNCOPENCALLS, OPENCALLS};
 use crate::pty_bus::PtyInstruction;
 use crate::screen::ScreenInstruction;
 
@@ -72,6 +72,12 @@ pub fn handle_panic(
     }
 }
 
+pub fn get_current_ctx() -> ErrorContext {
+    ASYNCOPENCALLS
+        .try_with(|ctx| *ctx.borrow())
+        .unwrap_or_else(|_| OPENCALLS.with(|ctx| *ctx.borrow()))
+}
+
 /// A representation of the call stack.
 #[derive(Clone, Copy)]
 pub struct ErrorContext {
@@ -95,7 +101,9 @@ impl ErrorContext {
                 break;
             }
         }
-        OPENCALLS.with(|ctx| *ctx.borrow_mut() = *self);
+        ASYNCOPENCALLS
+            .try_with(|ctx| *ctx.borrow_mut() = *self)
+            .unwrap_or_else(|_| OPENCALLS.with(|ctx| *ctx.borrow_mut() = *self));
     }
 }
 
diff --git a/src/common/input/handler.rs b/src/common/input/handler.rs
index 44065c67..0afcab10 100644
--- a/src/common/input/handler.rs
+++ b/src/common/input/handler.rs
@@ -58,9 +58,6 @@ impl InputHandler {
     fn handle_input(&mut self) {
         let mut err_ctx = OPENCALLS.with(|ctx| *ctx.borrow());
         err_ctx.add_call(ContextType::StdinHandler);
-        self.send_pty_instructions.update(err_ctx);
-        self.send_app_instructions.update(err_ctx);
-        self.send_screen_instructions.update(err_ctx);
         let keybinds = self.config.keybinds.clone();
         let alt_left_bracket = vec![27, 91];
         loop {
diff --git a/src/common/mod.rs b/src/common/mod.rs
index 2466aecf..19f8e4bc 100644
--- a/src/common/mod.rs
+++ b/src/common/mod.rs
@@ -25,9 +25,13 @@ use crate::cli::CliArgs;
 use crate::common::input::config::Config;
 use crate::layout::Layout;
 use crate::panes::PaneId;
+use async_std::task_local;
 use command_is_executing::CommandIsExecuting;
 use directories_next::ProjectDirs;
-use errors::{AppContext, ContextType, ErrorContext, PluginContext, PtyContext, ScreenContext};
+use errors::{
+    get_current_ctx, AppContext, ContextType, ErrorContext, PluginContext, PtyContext,
+    ScreenContext,
+};
 use input::handler::input_loop;
 use os_input_output::OsApi;
 use pty_bus::{PtyBus, PtyInstruction};
@@ -72,32 +76,23 @@ enum SenderType<T: Clone> {
 /// synchronously or asynchronously depending on the underlying [`SenderType`].
 #[derive(Clone)]
 pub struct SenderWithContext<T: Clone> {
-    err_ctx: ErrorContext,
     sender: SenderType<T>,
 }
 
 impl<T: Clone> SenderWithContext<T> {
-    fn new(err_ctx: ErrorContext, sender: SenderType<T>) -> Self {
-        Self { err_ctx, sender }
+    fn new(sender: SenderType<T>) -> Self {
+        Self { sender }
     }
 
     /// Sends an event, along with the current [`ErrorContext`], on this
     /// [`SenderWithContext`]'s channel.
     pub fn send(&self, event: T) -> Result<(), mpsc::SendError<(T, ErrorContext)>> {
+        let err_ctx = get_current_ctx();
         match self.sender {
-            SenderType::Sender(ref s) => s.send((event, self.err_ctx)),
-            SenderType::SyncSender(ref s) => s.send((event, self.err_ctx)),
+            SenderType::Sender(ref s) => s.send((event, err_ctx)),
+            SenderType::SyncSender(ref s) => s.send((event, err_ctx)),
         }
     }
-
-    /// Updates this [`SenderWithContext`]'s [`ErrorContext`]. This is the way one adds
-    /// a call to the error context.
-    ///
-    /// Updating [`ErrorContext`]s works in this way so that these contexts are only ever
-    /// allocated on the stack (which is thread-specific), and not on the heap.
-    pub fn update(&mut self, new_ctx: ErrorContext) {
-        self.err_ctx = new_ctx;
-    }
 }
 
 unsafe impl<T: Clone> Send for SenderWithContext<T> {}
@@ -109,6 +104,12 @@ thread_local!(
     static OPENCALLS: RefCell<ErrorContext> = RefCell::default()
 );
 
+task_local! {
+    /// A key to some thread local storage (TLS) that holds a representation of the task's call
+    /// stack in the form of an [`ErrorContext`].
+    static ASYNCOPENCALLS: RefCell<ErrorContext> = RefCell::default()
+}
+
 /// Instructions related to the entire application.
 #[derive(Clone)]
 pub enum AppInstruction {
@@ -140,25 +141,23 @@ pub fn start(mut os_input: Box<dyn OsApi>, opts: CliArgs) {
     let (send_screen_instructions, receive_screen_instructions): ChannelWithContext<
         ScreenInstruction,
     > = mpsc::channel();
-    let err_ctx = OPENCALLS.with(|ctx| *ctx.borrow());
-    let mut send_screen_instructions =
-        SenderWithContext::new(err_ctx, SenderType::Sender(send_screen_instructions));
+    let send_screen_instructions =
+        SenderWithContext::new(SenderType::Sender(send_screen_instructions));
 
     let (send_pty_instructions, receive_pty_instructions): ChannelWithContext<PtyInstruction> =
         mpsc::channel();
-    let mut send_pty_instructions =
-        SenderWithContext::new(err_ctx, SenderType::Sender(send_pty_instructions));
+    let send_pty_instructions = SenderWithContext::new(SenderType::Sender(send_pty_instructions));
 
     let (send_plugin_instructions, receive_plugin_instructions): ChannelWithContext<
         PluginInstruction,
     > = mpsc::channel();
     let send_plugin_instructions =
-        SenderWithContext::new(err_ctx, SenderType::Sender(send_plugin_instructions));
+        SenderWithContext::new(SenderType::Sender(send_plugin_instructions));
 
     let (send_app_instructions, receive_app_instructions): SyncChannelWithContext<AppInstruction> =
         mpsc::sync_channel(0);
     let send_app_instructions =
-        SenderWithContext::new(err_ctx, SenderType::SyncSender(send_app_instructions));
+        SenderWithContext::new(SenderType::SyncSender(send_app_instructions));
 
     let mut pty_bus = PtyBus::new(
         receive_pty_instructions,
@@ -195,7 +194,6 @@ pub fn start(mut os_input: Box<dyn OsApi>, opts: CliArgs) {
                     .recv()
                     .expect("failed to receive event on channel");
                 err_ctx.add_call(ContextType::Pty(PtyContext::from(&event)));
-                pty_bus.send_screen_instructions.update(err_ctx);
                 match event {
                     PtyInstruction::SpawnTerminal(file_to_open) => {
                         let pid = pty_bus.spawn_terminal(file_to_open);
@@ -272,8 +270,6 @@ pub fn start(mut os_input: Box<dyn OsApi>, opts: CliArgs) {
                         .recv()
                         .expect("failed to receive event on channel");
                     err_ctx.add_call(ContextType::Screen(ScreenContext::from(&event)));
-                    screen.send_app_instructions.update(err_ctx);
-                    screen.send_pty_instructions.update(err_ctx);
                     match event {
                         ScreenInstruction::PtyBytes(pid, vte_bytes) => {
                             let active_tab = screen.get_active_tab_mut().unwrap();
@@ -433,9 +429,9 @@ pub fn start(mut os_input: Box<dyn OsApi>, opts: CliArgs) {
     let wasm_thread = thread::Builder::new()
         .name("wasm".to_string())
         .spawn({
-            let mut send_pty_instructions = send_pty_instructions.clone();
-            let mut send_screen_instructions = send_screen_instructions.clone();
-            let mut send_app_instructions = send_app_instructions.clone();
+            let send_pty_instructions = send_pty_instructions.clone();
+            let send_screen_instructions = send_screen_instructions.clone();
+            let send_app_instructions = send_app_instructions.clone();
 
             let store = Store::default();
             let mut plugin_id = 0;
@@ -445,9 +441,6 @@ pub fn start(mut os_input: Box<dyn OsApi>, opts: CliArgs) {
                     .recv()
                     .expect("failed to receive event on channel");
                 err_ctx.add_call(ContextType::Plugin(PluginContext::from(&event)));
-                send_screen_instructions.update(err_ctx);
-                send_pty_instructions.update(err_ctx);
-                send_app_instructions.update(err_ctx);
                 match event {
                     PluginInstruction::Load(pid_tx, path) => {
                         let project_dirs =
@@ -556,16 +549,14 @@ pub fn start(mut os_input: Box<dyn OsApi>, opts: CliArgs) {
         .name("ipc_server".to_string())
         .spawn({
             use std::io::Read;
-            let mut send_pty_instructions = send_pty_instructions.clone();
-            let mut send_screen_instructions = send_screen_instructions.clone();
+            let send_pty_instructions = send_pty_instructions.clone();
+            let send_screen_instructions = send_screen_instructions.clone();
             move || {
                 std::fs::remove_file(ZELLIJ_IPC_PIPE).ok();
                 let listener = std::os::unix::net::UnixListener::bind(ZELLIJ_IPC_PIPE)
                     .expect("could not listen on ipc socket");
                 let mut err_ctx = OPENCALLS.with(|ctx| *ctx.borrow());
                 err_ctx.add_call(ContextType::IpcServer);
-                send_pty_instructions.update(err_ctx);
-                send_screen_instructions.update(err_ctx);
 
                 for stream in listener.incoming() {
                     match stream {
@@ -637,8 +628,6 @@ pub fn start(mut os_input: Box<dyn OsApi>, opts: CliArgs) {
             .expect("failed to receive app instruction on channel");
 
         err_ctx.add_call(ContextType::App(AppContext::from(&app_instruction)));
-        send_screen_instructions.update(err_ctx);
-        send_pty_instructions.update(err_ctx);
         match app_instruction {
             AppInstruction::Exit => {
                 break;
diff --git a/src/common/pty_bus.rs b/src/common/pty_bus.rs
index 2cab8ae8..28ae62f2 100644
--- a/src/common/pty_bus.rs
+++ b/src/common/pty_bus.rs
@@ -8,11 +8,11 @@ use ::std::sync::mpsc::Receiver;
 use ::std::time::{Duration, Instant};
 use std::path::PathBuf;
 
-use super::{ScreenInstruction, SenderWithContext, OPENCALLS};
+use super::{ScreenInstruction, SenderWithContext};
 use crate::os_input_output::OsApi;
 use crate::utils::logging::debug_to_file;
 use crate::{
-    errors::{ContextType, ErrorContext},
+    errors::{get_current_ctx, ContextType, ErrorContext},
     panes::PaneId,
 };
 use crate::{layout::Layout, wasm_vm::PluginInstruction};
@@ -89,15 +89,14 @@ pub struct PtyBus {
 
 fn stream_terminal_bytes(
     pid: RawFd,
-    mut send_screen_instructions: SenderWithContext<ScreenInstruction>,
+    send_screen_instructions: SenderWithContext<ScreenInstruction>,
     os_input: Box<dyn OsApi>,
     debug: bool,
 ) -> JoinHandle<()> {
-    let mut err_ctx = OPENCALLS.with(|ctx| *ctx.borrow());
+    let mut err_ctx = get_current_ctx();
     task::spawn({
         async move {
             err_ctx.add_call(ContextType::AsyncTask);
-            send_screen_instructions.update(err_ctx);
             let mut terminal_bytes = ReadFromPid::new(&pid, os_input);
 
             let mut last_byte_receive_time: Option<Instant> = None;