Add wayland interface check binary

This will let us write a script that ensures the necessary wayland interfaces exist and otherwise fall back to x11.

.github/workflows/cid.yml

@@ -57,6 +57,7 @@ jobs:
           cargo publish --package clipboard-history-server
           cargo publish --package clipboard-history
           cargo publish --package clipboard-history-x11
+          cargo publish --package wayland-interface-check
           cargo publish --package clipboard-history-egui
           cargo publish --package clipboard-history-tui
 
@@ -126,6 +127,13 @@ jobs:
           file: target/${{ matrix.target }}/release/ringboard-x11
           asset_name: ${{ matrix.target }}-ringboard-x11
           tag: ${{ github.ref }}
+      - name: Upload binary
+        uses: svenstaro/upload-release-action@v2
+        with:
+          repo_token: ${{ secrets.GITHUB_TOKEN }}
+          file: target/${{ matrix.target }}/release/wayland-interface-check
+          asset_name: ${{ matrix.target }}-wayland-interface-check
+          tag: ${{ github.ref }}
       - name: Upload binary
         uses: svenstaro/upload-release-action@v2
         with:

Cargo.toml

@@ -6,6 +6,7 @@ members = [
     "egui",
     "server",
     "tui",
+    "wayland-interface-check",
     "x11",
 ]
 

wayland-interface-check/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "wayland-interface-check"
+version = "0.1.0"
+authors.workspace = true
+edition.workspace = true
+description = "Binary to answer the question, \"Is this Wayland interface available?\""
+repository.workspace = true
+keywords = ["tools", "wayland", "cli"]
+categories = ["command-line-utilities", "development-tools"]
+license.workspace = true
+
+[dependencies]
+rustc-hash = "2.0.0"
+wayland-client = "0.31.7"

wayland-interface-check/LICENSE

@@ -0,0 +1 @@
+../LICENSE-APACHE

wayland-interface-check/README.md

@@ -0,0 +1,13 @@
+# Wayland interface check
+
+<a href="https://crates.io/crates/wayland-interface-check">![Crates.io Version](https://img.shields.io/crates/v/wayland-interface-check)</a>
+
+This simple binary answers the question, "Is this Wayland interface available?" For example,
+
+```sh
+$ wayland-interface-check zwlr_data_control_manager_v1
+$ echo $?
+0
+```
+
+means the interface is available.

wayland-interface-check/src/main.rs

@@ -0,0 +1,68 @@
+#![feature(exitcode_exit_method)]
+
+use std::{
+    collections::HashSet, env, ffi::OsString, hash::BuildHasherDefault, os::unix::ffi::OsStringExt,
+    process::ExitCode,
+};
+
+use rustc_hash::FxHasher;
+use wayland_client::{
+    Connection, Dispatch, QueueHandle,
+    protocol::{wl_registry, wl_registry::WlRegistry},
+};
+
+fn main() -> ExitCode {
+    let interfaces = env::args_os()
+        .skip(1)
+        .map(OsString::into_vec)
+        .collect::<HashSet<_, _>>();
+    if interfaces.is_empty() {
+        return ExitCode::SUCCESS;
+    }
+
+    let Ok(conn) = Connection::connect_to_env() else {
+        return ExitCode::FAILURE;
+    };
+    let display = conn.display();
+
+    let mut event_queue = conn.new_event_queue();
+    let qh = event_queue.handle();
+
+    let mut state = State(interfaces);
+
+    display.get_registry(&qh, ());
+    let Ok(_) = event_queue.roundtrip(&mut state) else {
+        return ExitCode::FAILURE;
+    };
+
+    if state.0.is_empty() {
+        ExitCode::SUCCESS
+    } else {
+        ExitCode::FAILURE
+    }
+}
+
+struct State(HashSet<Vec<u8>, BuildHasherDefault<FxHasher>>);
+
+impl Dispatch<WlRegistry, ()> for State {
+    fn event(
+        this: &mut Self,
+        _: &WlRegistry,
+        event: wl_registry::Event,
+        (): &(),
+        _: &Connection,
+        _: &QueueHandle<Self>,
+    ) {
+        if let wl_registry::Event::Global {
+            name: _,
+            interface,
+            version: _,
+        } = event
+        {
+            this.0.remove(interface.as_bytes());
+            if this.0.is_empty() {
+                ExitCode::SUCCESS.exit_process()
+            }
+        }
+    }
+}