rust-jack quickstart code

Author: y-usuzumi

.envrc

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+use flake

.gitignore

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+/target
+.direnv
+.vscode

Cargo.lock

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+[package]
+name = "step-sequencer"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+jack = "0.13.0"

Cargo.toml

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+{
+  description = "A Nix-flake-based Rust development environment";
+
+  inputs = {
+    nixpkgs.url = "https://flakehub.com/f/NixOS/nixpkgs/0.1.*.tar.gz";
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+  outputs = { self, nixpkgs, rust-overlay }:
+    let
+      supportedSystems = [ "x86_64-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin" ];
+      forEachSupportedSystem = f: nixpkgs.lib.genAttrs supportedSystems (system: f {
+        pkgs = import nixpkgs {
+          inherit system;
+          overlays = [ rust-overlay.overlays.default self.overlays.default ];
+        };
+      });
+    in
+    {
+      overlays.default = final: prev: {
+        rustToolchain =
+          let
+            rust = prev.rust-bin;
+          in
+          if builtins.pathExists ./rust-toolchain.toml then
+            rust.fromRustupToolchainFile ./rust-toolchain.toml
+          else if builtins.pathExists ./rust-toolchain then
+            rust.fromRustupToolchainFile ./rust-toolchain
+          else
+            rust.stable.latest.default.override {
+              extensions = [ "rust-src" "rustfmt" ];
+            };
+      };
+
+      devShells = forEachSupportedSystem ({ pkgs }: {
+        default = pkgs.mkShell {
+          packages = with pkgs; [
+            rustToolchain
+            openssl
+            libjack2
+            pkg-config
+            cargo-deny
+            cargo-edit
+            cargo-watch
+            rust-analyzer
+          ];
+
+          env = {
+            # Required by rust-analyzer
+            RUST_SRC_PATH = "${pkgs.rustToolchain}/lib/rustlib/src/rust/library";
+          };
+        };
+      });
+    };
+}

flake.lock

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+[toolchain]
+channel = "stable"
+

flake.nix

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+use std::io;
+
+fn main() {
+    // 1. Create client
+    let (client, _status) =
+        jack::Client::new("rust_jack_simple", jack::ClientOptions::default()).unwrap();
+
+    // 2. Register ports. They will be used in a callback that will be
+    // called when new data is available.
+    let in_a: jack::Port<jack::AudioIn> = client
+        .register_port("二狗_左声道", jack::AudioIn::default())
+        .unwrap();
+    let in_b: jack::Port<jack::AudioIn> = client
+        .register_port("二狗_右声道", jack::AudioIn::default())
+        .unwrap();
+    let mut out_a: jack::Port<jack::AudioOut> = client
+        .register_port("大马猴_左声道", jack::AudioOut::default())
+        .unwrap();
+    let mut out_b: jack::Port<jack::AudioOut> = client
+        .register_port("大马猴_右声道", jack::AudioOut::default())
+        .unwrap();
+    let process_callback = move |_: &jack::Client, ps: &jack::ProcessScope| -> jack::Control {
+        let out_a_p = out_a.as_mut_slice(ps);
+        let out_b_p = out_b.as_mut_slice(ps);
+        let in_a_p = in_a.as_slice(ps);
+        let in_b_p = in_b.as_slice(ps);
+        out_a_p.clone_from_slice(in_a_p);
+        out_b_p.clone_from_slice(in_b_p);
+        jack::Control::Continue
+    };
+    let process = jack::contrib::ClosureProcessHandler::new(process_callback);
+
+    // 3. Activate the client, which starts the processing.
+    let active_client = client.activate_async((), process).unwrap();
+
+    // 4. Wait for user input to quit
+    println!("Press enter/return to quit...");
+    let mut user_input = String::new();
+    io::stdin().read_line(&mut user_input).ok();
+
+    // 5. Not needed as the async client will cease processing on `drop`.
+    if let Err(err) = active_client.deactivate() {
+        eprintln!("JACK exited with error: {err}");
+    }
+}