`niri_ipc::Socket`; `niri msg version`; version checking on IPC (#278)

* Implement version checking in IPC

implement version checking; streamed IPC

streamed IPC will allow multiple requests per connection

add nonsense request

change inline struct to json macro

only check version if request actually fails

fix usage of inspect_err (MSRV 1.72.0; stabilized 1.76.0)

"nonsense request" -> "return error"

oneshot connections

* Change some things around

* Unqualify niri_ipc::Transform

---------

Co-authored-by: Ivan Molodetskikh <yalterz@gmail.com>

1 files changed, 8 insertions, 2 deletions

diff --git a/niri-ipc/src/lib.rs b/niri-ipc/src/lib.rs
index 33d25f2d..26b89283 100644
--- a/niri-ipc/src/lib.rs
+++ b/niri-ipc/src/lib.rs
@@ -6,18 +6,22 @@ use std::str::FromStr;
 
 use serde::{Deserialize, Serialize};
 
-/// Name of the environment variable containing the niri IPC socket path.
-pub const SOCKET_PATH_ENV: &str = "NIRI_SOCKET";
+mod socket;
+pub use socket::{Socket, SOCKET_PATH_ENV};
 
 /// Request from client to niri.
 #[derive(Debug, Serialize, Deserialize, Clone)]
 pub enum Request {
+    /// Request the version string for the running niri instance.
+    Version,
     /// Request information about connected outputs.
     Outputs,
     /// Request information about the focused window.
     FocusedWindow,
     /// Perform an action.
     Action(Action),
+    /// Respond with an error (for testing error handling).
+    ReturnError,
 }
 
 /// Reply from niri to client.
@@ -35,6 +39,8 @@ pub type Reply = Result<Response, String>;
 pub enum Response {
     /// A request that does not need a response was handled successfully.
     Handled,
+    /// The version string for the running niri instance.
+    Version(String),
     /// Information about connected outputs.
     ///
     /// Map from connector name to output info.