presto

Development

This page is for contributors working on Presto locally.

Prerequisites

• Rust toolchain (stable)
• ALSA/PulseAudio/PipeWire audio output (depending on your Linux setup)
• A working user session D-Bus if you want to exercise MPRIS

Common commands

Build:

cargo build

Run (scan current directory):

cargo run

Run with a directory:

cargo run -- /path/to/music

Run tests:

cargo test

Format:

cargo fmt

Lint:

cargo clippy

Where to start in the code

• src/main.rs: event loop and glue code
• src/app.rs: application state and navigation/filtering logic
• src/ui.rs: ratatui layout and rendering
• src/audio.rs: audio thread, queue semantics, crossfade/seek behavior
• src/mpris.rs: MPRIS D-Bus interface implementation

Debugging tips

Audio issues

• If you get ERR: No audio output device, rodio could not open a default output device.
  • Check that an output device exists and your user can access it.
  • If you run in a container/SSH session, you may not have an audio device.

MPRIS issues

• If Presto runs but playerctl -l does not show it:
  • You are likely missing a user session bus (common on headless shells).

TUI rendering/input

• If input feels unresponsive, make sure you’re not in a terminal multiplexer mode that eats key chords.
• Run with a larger terminal size when debugging layout problems; the UI intentionally uses fixed vertical sections.

Design constraints (practical)

• Presto keeps the audio thread as the owner of the rodio sink.
• The UI thread is intentionally dumb: it renders from App and sends commands.
• Seeking is implemented via sink rebuild + decoder skipping, which is simple and works widely, but isn’t perfect for all codecs.

See ARCHITECTURE.md for the deeper explanation.

This site is open source. Improve this page.