Imported from pentago/waybar-niri-focused-workspaces-module (AGENTS.md). Install upstream with npx skills add pentago/waybar-niri-focused-workspaces-module. Copyright stays with the author.

AGENTS.md

Rust cdylib loaded via Waybar's CFFI ABI. Shows niri workspaces of the focused output on every bar (not the bar's own output). Single purpose, small codebase: src/lib.rs (GTK widget logic) + src/ipc.rs (niri IPC over Unix socket).

Build

make          # cargo build --release + man page
make check    # cargo test

Requires: libgtk-3-dev (Debian) or gtk3 (Arch), scdoc for man page, NIRI_SOCKET env var for runtime (niri must be running).

Output: target/release/libniri_focused_workspaces.so

Tests

Unit tests only, inline in src/lib.rs (#[cfg(test)] mod tests). Run with cargo test. No integration tests, no CI test step beyond release workflow.

Architecture

• wbcffi_init / wbcffi_update / wbcffi_deinit are the CFFI entry points called by Waybar.
• Background thread subscribes to niri's EventStream via Unix socket; workspace events trigger a re-fetch.
• All GTK calls are raw FFI (*-sys crates, no safe wrappers). All unsafe blocks are deliberate — this is a C ABI boundary.
• wbcffi_version (static, value 2) must match Waybar's expected ABI version.

Conventions

• No rustfmt.toml, no clippy config, no linter — bare Rust project.
• Format strings in label_text substitute {icon}, {value}, {name}, {index}, {output} literally (no format specs).
• Logging: warn() macro prints to stderr with niri-focused-workspaces: prefix.