feat(dap): implement Restart request (#5651)

Add a restart debug session command, which would issue a
[Restart Request][1], if the debugger supports it and a session is
running. It uses the same arguments and requests used to start the
initial session, when recreating it.

It builds upon #5532, making use of the changes to the termination
workflow of a session.

[1]: https://microsoft.github.io/debug-adapter-protocol/specification#Requests_Restart

Closes: #5594

Signed-off-by: Filip Dutescu <filip.dutescu@gmail.com>

helix-dap/src/client.rs

@@ -33,6 +33,7 @@ pub struct Client {
     server_tx: UnboundedSender<Payload>,
     request_counter: AtomicU64,
     connection_type: Option<ConnectionType>,
+    starting_request_args: Option<Value>,
     pub caps: Option<DebuggerCapabilities>,
     // thread_id -> frames
     pub stack_frames: HashMap<ThreadId, Vec<StackFrame>>,
@@ -87,6 +88,7 @@ impl Client {
             request_counter: AtomicU64::new(0),
             caps: None,
             connection_type: None,
+            starting_request_args: None,
             stack_frames: HashMap::new(),
             thread_states: HashMap::new(),
             thread_id: None,
@@ -158,6 +160,10 @@ impl Client {
         )
     }
 
+    pub fn starting_request_args(&self) -> &Option<Value> {
+        &self.starting_request_args
+    }
+
     pub async fn tcp_process(
         cmd: &str,
         args: Vec<&str>,
@@ -356,14 +362,25 @@ impl Client {
 
     pub fn launch(&mut self, args: serde_json::Value) -> impl Future<Output = Result<Value>> {
         self.connection_type = Some(ConnectionType::Launch);
+        self.starting_request_args = Some(args.clone());
         self.call::<requests::Launch>(args)
     }
 
     pub fn attach(&mut self, args: serde_json::Value) -> impl Future<Output = Result<Value>> {
         self.connection_type = Some(ConnectionType::Attach);
+        self.starting_request_args = Some(args.clone());
         self.call::<requests::Attach>(args)
     }
 
+    pub fn restart(&self) -> impl Future<Output = Result<Value>> {
+        let args = if let Some(args) = &self.starting_request_args {
+            args.clone()
+        } else {
+            Value::Null
+        };
+        self.call::<requests::Restart>(args)
+    }
+
     pub async fn set_breakpoints(
         &self,
         file: PathBuf,

helix-dap/src/types.rs

@@ -378,7 +378,7 @@ pub mod requests {
 
     impl Request for Launch {
         type Arguments = Value;
-        type Result = Value;
+        type Result = ();
         const COMMAND: &'static str = "launch";
     }
 
@@ -387,7 +387,7 @@ pub mod requests {
 
     impl Request for Attach {
         type Arguments = Value;
-        type Result = Value;
+        type Result = ();
         const COMMAND: &'static str = "attach";
     }
 
@@ -402,6 +402,15 @@ pub mod requests {
         pub suspend_debuggee: Option<bool>,
     }
 
+    #[derive(Debug)]
+    pub enum Restart {}
+
+    impl Request for Restart {
+        type Arguments = Value;
+        type Result = ();
+        const COMMAND: &'static str = "restart";
+    }
+
     #[derive(Debug)]
     pub enum Disconnect {}