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|
//! A terminal backend for glimmer, behind a C ABI — `libjolttui.so`.
//!
//! [`glimmer-tui`](https://github.com/jolt-lang/glimmer-tui) is the design this
//! follows: the same tags, the same props, the same keyboard, and the same rule
//! that painting goes through a grid so a test needs no terminal. What is
//! different is where the widget layer lives. There it is jolt over ncurses;
//! here it is Rust behind the same retained-tree ABI `libvidya` already
//! exports, so one glimmer backend on the jolt side can drive a GPU window or a
//! terminal by naming a different shared object.
//!
//! That split is the point. A reconciler needs widgets to patch, and a terminal
//! has none — so the tree lives down here, and FFI traffic tracks *edits*
//! rather than frames: a static screen costs no crossings per frame, and only
//! what the reconciler actually changed is sent.
//!
//! Rules inherited from this workspace's ABI:
//!
//! * one session per process;
//! * every call stays on the thread that opened it — the session lives in
//! thread-local storage, so a call from another thread is inert rather than
//! unsound;
//! * only integers, doubles, and UTF-8 byte strings cross, and a returned
//! string is borrowed until the next one of its family;
//! * nothing calls back. Interactions queue, and the caller polls.
//!
//! Handlers never cross the boundary: a node reports that it was clicked, and
//! the caller looks up whose `:on-click` that was.
// Without the terminal feature the flush path is gone, and with it the only
// caller of a handful of screen and session accessors. They are the ABI's
// vocabulary, not dead code, so a headless build does not warn about them.
#![cfg_attr(not(feature = "terminal"), allow(dead_code))]
mod entry;
mod graphics;
mod keys;
mod layout;
mod paint;
mod screen;
#[cfg(feature = "terminal")]
mod term;
mod tree;
mod ui;
#[cfg(test)]
mod tests;
use std::cell::RefCell;
use std::ffi::{c_char, c_double, c_int};
use jolt_abi::{borrowed, empty_str, guard, Scratch};
use tree::Value;
use ui::Ui;
/// The reads: a prop, a tag, a line of the screen. One scratch, so a caller
/// holding a tag pointer across a prop read gets the documented lifetime and
/// not a surprise.
static READS: Scratch = Scratch::new();
/// Dumps are their own family: a dump is usually being printed beside the
/// props it mentions.
static DUMPS: Scratch = Scratch::new();
/// The event name and the event text are read one after the other by every
/// caller there will ever be, so they cannot share a scratch.
static NAMES: Scratch = Scratch::new();
static EVENTS: Scratch = Scratch::new();
struct Session {
ui: Ui,
#[cfg(feature = "terminal")]
term: Option<term::Term>,
}
thread_local! {
/// The process's session, owned by the thread that opened it.
static SESSION: RefCell<Option<Session>> = const { RefCell::new(None) };
}
fn with<R: Copy>(fallback: R, f: impl FnOnce(&mut Session) -> R) -> R {
guard(fallback, || {
SESSION.with_borrow_mut(|slot| match slot.as_mut() {
Some(session) => f(session),
None => fallback,
})
})
}
/// Most of this ABI is a call on the tree with a session around it.
fn with_ui<R: Copy>(fallback: R, f: impl FnOnce(&mut Ui) -> R) -> R {
with(fallback, |session| f(&mut session.ui))
}
// ── the session ─────────────────────────────────────────────────────────────
/// Take the terminal. `mouse` non-zero turns on mouse reporting. 1 on success,
/// 0 if a session is already open or the terminal refused raw mode.
#[no_mangle]
pub extern "C" fn tui_open(mouse: c_int) -> c_int {
guard(0, || {
SESSION.with_borrow_mut(|slot| {
if slot.is_some() {
log::error!("jolt-tui: a session is already open");
return 0;
}
#[cfg(feature = "terminal")]
{
match term::Term::open(mouse != 0) {
Ok(term) => {
let (w, h) = term.size();
*slot = Some(Session {
ui: Ui::new(w, h),
term: Some(term),
});
1
}
Err(e) => {
log::error!("jolt-tui: could not take the terminal: {e}");
0
}
}
}
#[cfg(not(feature = "terminal"))]
{
let _ = mouse;
log::error!("jolt-tui: built without the terminal feature");
0
}
})
})
}
/// Open a session with no terminal at all, at a fixed size.
///
/// The whole widget layer works here — layout, painting, focus, keys fed with
/// `tui_feed_key` — and `tui_screen_line` reads the result back. This is what a
/// test suite and CI use, and it is the same code path a real session paints
/// through, not a second implementation of it.
#[no_mangle]
pub extern "C" fn tui_headless(width: c_int, height: c_int) -> c_int {
guard(0, || {
SESSION.with_borrow_mut(|slot| {
if slot.is_some() {
return 0;
}
*slot = Some(Session {
ui: Ui::new(
width.clamp(1, u16::MAX as c_int) as u16,
height.clamp(1, u16::MAX as c_int) as u16,
),
#[cfg(feature = "terminal")]
term: None,
});
1
})
})
}
/// Give the terminal back and drop the tree. Safe to call twice.
#[no_mangle]
pub extern "C" fn tui_close() {
guard((), || {
SESSION.with_borrow_mut(|slot| {
#[cfg(feature = "terminal")]
if let Some(session) = slot.as_mut() {
if let Some(term) = session.term.as_mut() {
term.close();
}
}
*slot = None;
})
})
}
#[no_mangle]
pub extern "C" fn tui_should_close() -> c_int {
with_ui(1, |ui| ui.should_close() as c_int)
}
#[no_mangle]
pub extern "C" fn tui_quit() {
with_ui((), |ui| ui.quit())
}
/// Wait up to `timeout_ms` for input, then handle everything that arrived.
/// Answers how many things it handled, so a caller can skip a repaint when
/// nothing happened. Inert in a headless session, which is fed by hand.
#[no_mangle]
pub extern "C" fn tui_tick(timeout_ms: c_int) -> c_int {
with(0, |session| {
#[cfg(feature = "terminal")]
{
let Some(term) = session.term.as_mut() else {
return 0;
};
let inputs = term.poll(timeout_ms.max(0) as u64);
let mut handled = 0;
for input in inputs {
handled += 1;
match input {
term::Input::Key(name) => {
session.ui.key(&name);
}
term::Input::Click(x, y) => {
session.ui.click(x, y);
}
term::Input::Wheel(x, y, by) => {
session.ui.wheel(x, y, by);
}
term::Input::Resize(w, h) => session.ui.resize(w, h),
}
}
handled
}
#[cfg(not(feature = "terminal"))]
{
let _ = (session, timeout_ms);
0
}
})
}
/// Lay the tree out, paint it, and send what changed. A headless session paints
/// and stops there.
#[no_mangle]
pub extern "C" fn tui_frame() {
with((), |session| {
session.ui.frame();
#[cfg(feature = "terminal")]
if let Some(term) = session.term.as_mut() {
let cursor = session.ui.cursor();
let images = session.ui.images().to_vec();
if let Err(e) = term.flush(&session.ui.screen, cursor, &images) {
log::error!("jolt-tui: could not write a frame: {e}");
}
}
})
}
#[no_mangle]
pub extern "C" fn tui_screen_width() -> c_int {
with_ui(0, |ui| ui.screen.width() as c_int)
}
#[no_mangle]
pub extern "C" fn tui_screen_height() -> c_int {
with_ui(0, |ui| ui.screen.height() as c_int)
}
/// One painted row as text, trailing blanks trimmed — what a test asserts on,
/// and what a bug report pastes. Borrowed until the next read.
#[no_mangle]
pub extern "C" fn tui_screen_line(y: c_int) -> *const c_char {
with_ui(empty_str(), |ui| {
if y < 0 {
return empty_str();
}
READS.lend(ui.screen.line(y as u16))
})
}
// ── input by hand ───────────────────────────────────────────────────────────
/// Feed one key by name — `"ctrl+u"`, `"page-down"`, `"a"` — as if the terminal
/// had sent it. Answers 1 when the backend acted on it and 0 when it went out
/// as a `key` event instead.
///
/// # Safety
/// `name` is null or a NUL-terminated UTF-8 string.
#[no_mangle]
pub unsafe extern "C" fn tui_feed_key(name: *const c_char) -> c_int {
let name = borrowed(name);
with_ui(0, |ui| ui.key(&name) as c_int)
}
#[no_mangle]
pub extern "C" fn tui_feed_click(x: c_int, y: c_int) -> c_int {
with_ui(0, |ui| {
if x < 0 || y < 0 {
return 0;
}
ui.click(x as u16, y as u16) as c_int
})
}
#[no_mangle]
pub extern "C" fn tui_feed_wheel(x: c_int, y: c_int, by: c_int) -> c_int {
with_ui(0, |ui| {
if x < 0 || y < 0 {
return 0;
}
ui.wheel(x as u16, y as u16, by) as c_int
})
}
/// The focused node, 0 for none.
#[no_mangle]
pub extern "C" fn tui_focus() -> c_int {
with_ui(0, |ui| ui.focus() as c_int)
}
// ── the tree ────────────────────────────────────────────────────────────────
#[no_mangle]
pub extern "C" fn tui_tree_root() -> c_int {
with_ui(0, |ui| ui.tree.root() as c_int)
}
/// # Safety
/// `tag` is null or a NUL-terminated UTF-8 string.
#[no_mangle]
pub unsafe extern "C" fn tui_node_new(tag: *const c_char) -> c_int {
let tag = borrowed(tag);
with_ui(0, |ui| ui.tree.new_node(&tag) as c_int)
}
#[no_mangle]
pub extern "C" fn tui_node_free(node: c_int) {
with_ui((), |ui| ui.tree.free_node(node.max(0) as u32))
}
#[no_mangle]
pub extern "C" fn tui_node_exists(node: c_int) -> c_int {
with_ui(0, |ui| ui.tree.exists(node.max(0) as u32) as c_int)
}
/// # Safety
/// `key` and `value` are null or NUL-terminated UTF-8 strings.
#[no_mangle]
pub unsafe extern "C" fn tui_node_set_str(node: c_int, key: *const c_char, value: *const c_char) {
let (key, value) = (borrowed(key), borrowed(value));
with_ui((), |ui| {
ui.tree.set(node.max(0) as u32, &key, Value::Str(value))
})
}
/// # Safety
/// `key` is null or a NUL-terminated UTF-8 string.
#[no_mangle]
pub unsafe extern "C" fn tui_node_set_num(node: c_int, key: *const c_char, value: c_double) {
let key = borrowed(key);
with_ui((), |ui| {
ui.tree.set(node.max(0) as u32, &key, Value::Num(value))
})
}
/// # Safety
/// `key` is null or a NUL-terminated UTF-8 string.
#[no_mangle]
pub unsafe extern "C" fn tui_node_set_bool(node: c_int, key: *const c_char, value: c_int) {
let key = borrowed(key);
with_ui((), |ui| {
ui.tree
.set(node.max(0) as u32, &key, Value::Bool(value != 0))
})
}
#[no_mangle]
pub extern "C" fn tui_node_clear_props(node: c_int) {
with_ui((), |ui| ui.tree.clear_props(node.max(0) as u32))
}
/// # Safety
/// `key` is null or a NUL-terminated UTF-8 string.
#[no_mangle]
pub unsafe extern "C" fn tui_node_get_str(node: c_int, key: *const c_char) -> *const c_char {
let key = borrowed(key);
with_ui(empty_str(), |ui| {
match ui.tree.get(node.max(0) as u32, &key) {
Some(Value::Str(text)) => READS.lend(text.clone()),
_ => empty_str(),
}
})
}
/// # Safety
/// `key` is null or a NUL-terminated UTF-8 string.
#[no_mangle]
pub unsafe extern "C" fn tui_node_get_num(node: c_int, key: *const c_char) -> c_double {
let key = borrowed(key);
with_ui(0.0, |ui| match ui.tree.get(node.max(0) as u32, &key) {
Some(Value::Num(n)) => *n,
Some(Value::Bool(b)) => *b as i32 as f64,
_ => 0.0,
})
}
/// # Safety
/// `key` is null or a NUL-terminated UTF-8 string.
#[no_mangle]
pub unsafe extern "C" fn tui_node_get_bool(node: c_int, key: *const c_char) -> c_int {
let key = borrowed(key);
with_ui(0, |ui| match ui.tree.get(node.max(0) as u32, &key) {
Some(Value::Bool(b)) => *b as c_int,
Some(Value::Num(n)) => (*n != 0.0) as c_int,
_ => 0,
})
}
#[no_mangle]
pub extern "C" fn tui_node_tag(node: c_int) -> *const c_char {
with_ui(empty_str(), |ui| {
READS.lend(ui.tree.tag_name(node.max(0) as u32).to_owned())
})
}
/// The node this one hangs off, 0 when it is unparented or is the window.
#[no_mangle]
pub extern "C" fn tui_node_parent(node: c_int) -> c_int {
with_ui(0, |ui| ui.tree.parent(node.max(0) as u32) as c_int)
}
#[no_mangle]
pub extern "C" fn tui_node_child_count(node: c_int) -> c_int {
with_ui(0, |ui| ui.tree.child_count(node.max(0) as u32) as c_int)
}
#[no_mangle]
pub extern "C" fn tui_node_child_at(node: c_int, index: c_int) -> c_int {
with_ui(0, |ui| {
if index < 0 {
return 0;
}
ui.tree.child_at(node.max(0) as u32, index as usize) as c_int
})
}
#[no_mangle]
pub extern "C" fn tui_node_append(parent: c_int, child: c_int) -> c_int {
with_ui(0, |ui| {
ui.tree.append(parent.max(0) as u32, child.max(0) as u32) as c_int
})
}
#[no_mangle]
pub extern "C" fn tui_node_remove(parent: c_int, child: c_int) {
with_ui((), |ui| {
ui.tree.remove(parent.max(0) as u32, child.max(0) as u32)
})
}
#[no_mangle]
pub extern "C" fn tui_node_insert_after(parent: c_int, child: c_int, sibling: c_int) -> c_int {
with_ui(0, |ui| {
ui.tree.insert_after(
parent.max(0) as u32,
child.max(0) as u32,
sibling.max(0) as u32,
) as c_int
})
}
#[no_mangle]
pub extern "C" fn tui_node_replace(parent: c_int, old_child: c_int, new_child: c_int) -> c_int {
with_ui(0, |ui| {
ui.tree.replace(
parent.max(0) as u32,
old_child.max(0) as u32,
new_child.max(0) as u32,
) as c_int
})
}
/// The subtree at `node` as pretty-printed hiccup; `node` 0 means the root, so
/// `tui_tree_dump(0)` is the whole window.
#[no_mangle]
pub extern "C" fn tui_tree_dump(node: c_int) -> *const c_char {
with_ui(empty_str(), |ui| {
let id = if node <= 0 {
ui.tree.root()
} else {
node as u32
};
DUMPS.lend(ui.tree.dump(id))
})
}
// ── events ──────────────────────────────────────────────────────────────────
#[no_mangle]
pub extern "C" fn tui_tree_poll_event() -> c_int {
with_ui(0, |ui| ui.tree.poll() as c_int)
}
#[no_mangle]
pub extern "C" fn tui_tree_event_node() -> c_int {
with_ui(0, |ui| {
ui.tree.current().map_or(0, |event| event.node as c_int)
})
}
#[no_mangle]
pub extern "C" fn tui_tree_event_name() -> *const c_char {
with_ui(empty_str(), |ui| match ui.tree.current() {
Some(event) => NAMES.lend(event.name),
None => empty_str(),
})
}
#[no_mangle]
pub extern "C" fn tui_tree_event_text() -> *const c_char {
with_ui(empty_str(), |ui| match ui.tree.current() {
Some(event) => EVENTS.lend(event.text.clone()),
None => empty_str(),
})
}
#[no_mangle]
pub extern "C" fn tui_tree_event_num() -> c_double {
with_ui(0.0, |ui| ui.tree.current().map_or(0.0, |event| event.num))
}
|