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|
//! glimmer's libcosmic backend: the retained-tree ABI, with iced reading it.
//!
//! The edit half is libvidya's — integer node handles, string-keyed props,
//! events queued and polled — so `glimmer-cosmic` is `glimmer-vidya` pointed
//! at a different object. What changes is who owns the loop.
//!
//! egui lets its caller drive frames; iced does not. `cosmic::app::run` takes
//! the main thread (winit insists) and returns when the window closes. So the
//! arrangement is inverted:
//!
//! * `cosmic_run` blocks the process main thread inside libcosmic.
//! * jolt reconciles on a worker thread, mutating the arena under a mutex.
//! Nothing it does is visible until `cosmic_tree_commit`, which snapshots the
//! tree and wakes iced — so a reconcile half-way through a patch is never
//! painted, and a commit with no edits behind it costs nothing.
//! * Interactions are queued, and `cosmic_wait` blocks the worker until there
//! is one (or `cosmic_wake`, or a timeout), so an idle window burns no CPU on
//! either side.
//!
//! Every call except `cosmic_run` may come from any thread.
mod rows;
mod tree;
pub use tree::{Node, Prop, Tree};
use std::collections::{HashMap, HashSet, VecDeque};
use std::ffi::{c_char, c_int};
use std::path::PathBuf;
use std::sync::atomic::{AtomicBool, AtomicU32, AtomicU64, Ordering::SeqCst};
use std::sync::{Arc, Condvar, LazyLock, Mutex, MutexGuard};
use std::time::Duration;
use cosmic::app::{Core, Task};
use cosmic::iced::alignment::Horizontal;
use cosmic::iced::futures::channel::mpsc;
use cosmic::iced::futures::{Stream, StreamExt};
use cosmic::iced::widget::container::Style as ContainerStyle;
use cosmic::iced::widget::scrollable::{
self as iced_scrollable, AbsoluteOffset, RelativeOffset, Viewport,
};
use cosmic::iced::widget::text::Wrapping;
use cosmic::iced::{
Alignment, Background, Border, Color, ContentFit, Font, Length, Padding, Subscription,
};
use cosmic::widget::{self, Column, Row};
use cosmic::{ApplicationExt, Element};
use jolt_abi::{borrowed, empty_str, guard, Scratch};
fn lock<T>(m: &Mutex<T>) -> MutexGuard<'_, T> {
m.lock().unwrap_or_else(|poisoned| poisoned.into_inner())
}
// --- the arena ---------------------------------------------------------------
struct Edits {
tree: Tree,
/// Set by every mutation, cleared by a commit that published it.
dirty: bool,
}
static EDITS: LazyLock<Mutex<Edits>> = LazyLock::new(|| {
Mutex::new(Edits {
tree: Tree::default(),
dirty: false,
})
});
/// What `view` paints: the tree as of the last commit.
static COMMITTED: LazyLock<Mutex<Arc<Tree>>> = LazyLock::new(Default::default);
/// The inbox's `settled` when that commit was made. Written under
/// `COMMITTED`'s lock, so the two are read as a pair.
static COMMITTED_SETTLED: AtomicU64 = AtomicU64::new(0);
fn edit<R>(f: impl FnOnce(&mut Tree) -> R) -> R {
let mut e = lock(&EDITS);
e.dirty = true;
f(&mut e.tree)
}
fn read<R>(f: impl FnOnce(&Tree) -> R) -> R {
f(&lock(&EDITS).tree)
}
// --- events, towards jolt ----------------------------------------------------
struct Event {
seq: u64,
node: i32,
name: &'static str,
text: String,
num: f64,
}
struct Inbox {
queue: VecDeque<Event>,
current: Option<Event>,
woken: bool,
/// The sequence number of the last event posted.
posted: u64,
/// The sequence number of the last event the worker dequeued.
taken: u64,
/// `taken` as of the worker's last `cosmic_wait`. Every event up to here
/// had its handler run on an earlier pass, so whatever it re-rendered is
/// in the arena by the next commit.
settled: u64,
}
static INBOX: Mutex<Inbox> = Mutex::new(Inbox {
queue: VecDeque::new(),
current: None,
woken: false,
posted: 0,
taken: 0,
settled: 0,
});
static BELL: Condvar = Condvar::new();
fn post(node: i32, name: &'static str, text: String, num: f64) {
post_seq(node, name, text, num);
}
/// Queue an event for the worker; answers its sequence number.
fn post_seq(node: i32, name: &'static str, text: String, num: f64) -> u64 {
let seq = {
let mut inbox = lock(&INBOX);
inbox.posted += 1;
let seq = inbox.posted;
inbox.queue.push_back(Event {
seq,
node,
name,
text,
num,
});
seq
};
BELL.notify_all();
seq
}
// --- wakes, towards iced -----------------------------------------------------
enum Wake {
Tree,
Quit,
PickImage,
}
static TO_APP: Mutex<Option<mpsc::UnboundedSender<Wake>>> = Mutex::new(None);
static QUIT_ASKED: AtomicBool = AtomicBool::new(false);
static RAN: AtomicBool = AtomicBool::new(false);
static CLOSED: AtomicBool = AtomicBool::new(false);
/// The window's size in points, as libcosmic last reported it. A client that
/// lays columns out by arithmetic — frq sizes its message list against the
/// people panel beside it — has to be able to ask.
static WINDOW_W: AtomicU32 = AtomicU32::new(0);
static WINDOW_H: AtomicU32 = AtomicU32::new(0);
/// Where a picture chooser opened by `cosmic_pick_image` has got to.
enum Pick {
Idle,
Open,
Chosen(PathBuf),
}
static PICK: Mutex<Pick> = Mutex::new(Pick::Idle);
/// The picture a Ctrl+V found on the clipboard, held until the worker asks for
/// it with `cosmic_clipboard_image_png`.
static CLIPBOARD_PNG: Mutex<Option<Vec<u8>>> = Mutex::new(None);
/// The clipboard read as PNG. Only image/png is asked for: every desktop that
/// puts a picture on a clipboard puts one there as PNG too.
struct ClipboardPng(Vec<u8>);
impl cosmic::iced::clipboard::mime::AllowedMimeTypes for ClipboardPng {
fn allowed() -> std::borrow::Cow<'static, [String]> {
std::borrow::Cow::Owned(vec!["image/png".to_owned()])
}
}
impl TryFrom<(Vec<u8>, String)> for ClipboardPng {
type Error = ();
fn try_from((bytes, _mime): (Vec<u8>, String)) -> Result<Self, ()> {
if bytes.is_empty() {
Err(())
} else {
Ok(Self(bytes))
}
}
}
/// Named for emoji rather than left to fallback: the first face with a glyph
/// for a smiley is often a monochrome one, and the pill then shows an outline.
const EMOJI_FONT: Font = Font::with_name("Noto Color Emoji");
fn tell_app(wake: Wake) {
if let Some(tx) = lock(&TO_APP).as_ref() {
let _ = tx.unbounded_send(wake);
}
}
/// The subscription's stream. It opens with a `Tree` wake so a commit made
/// between `init` and the subscription starting is not missed, and repeats a
/// quit asked for before there was anyone to tell.
fn wakes() -> impl Stream<Item = Message> {
let (tx, rx) = mpsc::unbounded();
let _ = tx.unbounded_send(Wake::Tree);
if QUIT_ASKED.load(SeqCst) {
let _ = tx.unbounded_send(Wake::Quit);
}
*lock(&TO_APP) = Some(tx);
rx.map(|wake| match wake {
Wake::Tree => Message::Tree,
Wake::Quit => Message::Quit,
Wake::PickImage => Message::PickImage,
})
}
// --- scroll areas ------------------------------------------------------------
/// Where a scroll area was left, kept by name rather than on the widget.
///
/// iced keeps a scrollable's offset in its widget tree, and a widget that is
/// unmounted and mounted again starts at the top. glimmer clients unmount
/// lists all the time — frq's lightbox is a screen, so looking at a picture
/// takes the backlog away — so the place is remembered here, under the
/// `scroll-key` the client names the list by, and put back when it returns.
struct ScrollMemo {
/// Whether the reader is at the newest line. A `stick-to-bottom` list
/// follows what arrives only while this holds.
at_end: bool,
/// What the client was last told about that, and `None` while it has been
/// told nothing.
///
/// Held apart from `at_end` because the two answer different questions.
/// `at_end` is where this list is; `told` is what the client believes,
/// and a report is worth making exactly when they differ. Reporting on a
/// change in `at_end` alone loses two cases, and both of them end with a
/// "jump to present" button over a backlog that is already at its newest
/// line. A list mounting says nothing, because the place it opens at is
/// the place the memo guessed it would — but the client's belief is about
/// the list this one REPLACED, which in frq is another room entirely. And
/// a jump says nothing, because the branch that asked for it marked the
/// memo on the way past, so the report that came back agreed with it.
told: Option<bool>,
offset_y: f32,
/// How tall the viewport was when the reader last moved it, which is what
/// a jump centres a row in. Zero until they have: a list nobody has
/// scrolled has no reported height, and a row put in the middle of a
/// viewport of nothing is a row put at the top — which is the right answer
/// to give when the height is not known.
height: f32,
}
/// Two points of slack: a viewport scrolled to its end by a fractional
/// offset is still at the end.
const AT_END_SLACK: f32 = 2.0;
fn scroll_name(n: &Node, id: i32) -> String {
match n.str("scroll-key") {
"" => format!("node-{id}"),
key => key.to_owned(),
}
}
fn scroll_id(name: &str) -> widget::Id {
widget::Id::new(format!("jolt-scroll-{name}"))
}
fn walk<'t>(t: &'t Tree, id: i32, f: &mut impl FnMut(i32, &'t Node)) {
if let Some(n) = t.get(id) {
f(id, n);
for child in &n.children {
walk(t, *child, f);
}
}
}
/// What a commit asks of one scroll area.
struct ScrollAsk {
name: String,
stick: bool,
/// The `scroll-to-bottom` counter, and what it was in the tree before.
tick: Option<f64>,
tick_before: Option<f64>,
/// Not in the tree before this commit: mounted, or mounted again.
fresh: bool,
/// The row asking to be shown, if one is.
reveal: Option<i32>,
}
/// Every scroll area in `now`, and what changed about each since `before`.
fn scroll_asks(before: &Tree, now: &Tree) -> Vec<ScrollAsk> {
let mut named_before: HashMap<String, Option<f64>> = HashMap::new();
walk(before, before.root_id(), &mut |id, n| {
if n.tag == "scroll" {
named_before.insert(scroll_name(n, id), n.num("scroll-to-bottom"));
}
});
let mut asks = Vec::new();
walk(now, now.root_id(), &mut |id, n| {
if n.tag != "scroll" {
return;
}
let name = scroll_name(n, id);
// The row holding whatever asked to be shown.
//
// The row, because a row is what `rows::Rows` writes a place down for;
// and the row rather than a guess at where it sits, because this used
// to answer with its index over the row count. That is a fraction of
// the scroll RANGE and not of the content — the two agree only when
// the viewport is exactly one row tall — and it took every row for the
// same height besides, in a backlog that puts a one-line message next
// to a picture. The landing was out by up to a viewport, worst in the
// middle of a list.
//
// While it is asking, not only on the commit the ask arrives. A row
// that is not laid out yet has no place written down for it, and the
// ask is over in half a second: asking again each commit is what lets
// a jump into a conversation the client has only just switched to land
// on the frame the rows finally exist.
let mut reveal = None;
for row in &n.children {
let mut asked = false;
walk(now, *row, &mut |_, node| {
asked |= node.bool("scroll-here") == Some(true);
});
if asked {
reveal = Some(*row);
break;
}
}
asks.push(ScrollAsk {
fresh: !named_before.contains_key(&name),
tick_before: named_before.get(&name).copied().flatten(),
tick: n.num("scroll-to-bottom"),
stick: n.bool("stick-to-bottom") == Some(true),
reveal,
name,
});
});
asks
}
/// What a commit asks of one scroll area, decided.
#[derive(Debug, PartialEq)]
enum ScrollMove {
/// Show this row of it.
Reveal(i32),
/// Take it to its newest line.
End,
/// Put it back where the reader left it, in points.
Restore(f32),
/// Leave it alone.
Stay,
}
/// What to do with one scroll area, and the memo brought up to date.
///
/// Split out from `take_tree` because it is the whole of the thinking and none
/// of the toolkit: everything here is the ask beside what is remembered, so it
/// can be read — and tested — without a window to put it in.
fn scroll_move(ask: &ScrollAsk, memo: &mut ScrollMemo) -> ScrollMove {
// A list this tree did not have a moment ago is a list the client has
// heard nothing about, whatever it heard about the last one under this
// name. Forgetting what it was told is what makes the next report happen,
// so that what it believes is about the list it is looking at — in frq,
// the room it is in rather than the room it came from.
if ask.fresh {
memo.told = None;
}
let jumped = !ask.fresh && ask.tick.is_some() && ask.tick != ask.tick_before;
// A row is asking to be shown. Whether or not it can be shown yet,
// nothing else may move this list while it is asking: the branch below
// would otherwise take a reader who was at the newest line — which is
// most readers, most of the time — straight back to it, and a jump that
// ends at the bottom of the room reads as a jump that did nothing.
//
// Nothing below marks the memo, either. Where a list lands is `report`'s
// to hear from the toolkit and pass on; a memo that wrote the answer down
// here would agree with the report when it came and keep it from the
// client — the list moved, nobody was told, and the client went on
// believing whatever it believed before. Which is a "jump to present"
// button over a backlog that is already at its newest line.
if let Some(row) = ask.reveal {
ScrollMove::Reveal(row)
} else if jumped || (ask.stick && memo.at_end) {
ScrollMove::End
} else if ask.fresh {
ScrollMove::Restore(memo.offset_y)
} else {
ScrollMove::Stay
}
}
/// What to tell the client now that this list is at `at_end`, if anything.
///
/// Against what it was last told rather than against where the list was a
/// moment ago. The two are the same answer for a list the reader is moving by
/// hand, and they part company wherever something else moved it — see `told`.
fn report(memo: &mut ScrollMemo, at_end: bool) -> Option<&'static str> {
(memo.told != Some(at_end)).then(|| {
memo.told = Some(at_end);
// "end" or "away", the strings libvidya emits: frq's handler compares
// against "end".
if at_end {
"end"
} else {
"away"
}
})
}
/// Where the rows of the scroll area called `name` were last laid out.
///
/// By name and not by node, because a scroll area outlives the node ids of a
/// tree that is rebuilt under it — the same list, and the reader's place in
/// it, is the thing `scroll-key` names.
fn placements(name: &str) -> rows::Placements {
static BOOKS: LazyLock<Mutex<HashMap<String, rows::Placements>>> =
LazyLock::new(|| Mutex::new(HashMap::new()));
lock(&BOOKS).entry(name.to_owned()).or_default().clone()
}
/// Where to scroll so that a row at `top`, `height` tall, sits in the middle
/// of a viewport `viewport` tall.
///
/// The middle rather than the top edge: a line answered three days ago is read
/// with what was said around it, and a jump that pins it to the ceiling shows
/// only what came after.
///
/// Never above the start of the content — a negative offset is not a place —
/// and the top edge is the answer while the viewport's height is unknown,
/// which it is until the reader has scrolled the list once. A row centred in a
/// viewport of nothing is a row at the top, which is the same answer said
/// twice, but it is worth being the one that is said on purpose.
fn centred_offset(top: f32, height: f32, viewport: f32) -> f32 {
(top - (viewport - height).max(0.0) / 2.0).max(0.0)
}
/// Whether to say out loud what every jump decided, on stderr.
///
/// Set `JOLT_SCROLL_LOG` to anything. A jump is three numbers and a lookup,
/// and which of them is wrong is not a thing anyone can tell from a window
/// that scrolled to the wrong place.
fn scroll_log() -> bool {
static ON: LazyLock<bool> = LazyLock::new(|| std::env::var_os("JOLT_SCROLL_LOG").is_some());
*ON
}
/// How many frames a reveal keeps trying for.
///
/// A row is measured by the layout that draws it, so the frame a jump is asked
/// on is a frame too early: the places written down are the ones from before
/// the room changed. Twenty frames is a third of a second at sixty, which is
/// longer than a screen takes to build and shorter than a reader waits before
/// deciding nothing happened.
const REVEAL_TRIES: u8 = 20;
/// How many frames a list that has just mounted keeps asking for the place it
/// opens at.
///
/// `REVEAL_TRIES`' reasoning at the other end of the same problem. iced runs a
/// widget operation against the tree the last `view` built, so the ask that
/// goes out on the commit a scroll area ARRIVES on can find no such widget to
/// act on — the scrollable it names is one this frame is only now building.
/// Whether it lands is then a question of which happens first, which is not a
/// question a room should open on: most of the time the conversation opened at
/// its newest line and sometimes it opened at the top of the backlog.
///
/// Four frames rather than `reveal`'s twenty, and it stops the moment the list
/// reports that it arrived. A mount settles in one or two; what is left of the
/// budget after that is time spent fighting a reader who opened a room and
/// immediately scrolled, and there is no reason to spend more of it than the
/// mount actually needs.
const SETTLE_TRIES: u8 = 4;
/// Whether the list called `name` is already where a mount sent it — its end
/// for `None`, that offset for `Some`.
///
/// Read off the memo, which is to say off what the toolkit last reported, so
/// a list nobody has heard from yet has not arrived and is asked again.
fn settled(memo: Option<&ScrollMemo>, want: Option<f32>) -> bool {
match (memo, want) {
(None, _) => false,
(Some(m), None) => m.at_end,
(Some(m), Some(y)) => (m.offset_y - y).abs() <= AT_END_SLACK,
}
}
/// The row of the scroll area called `name` that is asking to be shown, as the
/// tree has it now.
///
/// Asked again on every attempt rather than carried, because a row is not the
/// same node for long. A buffer that takes a line while a jump is landing is
/// rebuilt under the reconciler, and the row that was node 412 a frame ago is
/// node 587 now — so a retry holding the old number would look up a place for
/// a row nobody has, and go on failing until it gave up. Which room a reader
/// jumped into decided whether it worked, and that is exactly as strange as
/// it sounds until you see what it depends on.
fn asking_row(t: &Tree, name: &str) -> Option<i32> {
let mut found = None;
walk(t, t.root_id(), &mut |id, n| {
if found.is_some() || n.tag != "scroll" || scroll_name(n, id) != name {
return;
}
for row in &n.children {
let mut asked = false;
walk(t, *row, &mut |_, node| {
asked |= node.bool("scroll-here") == Some(true);
});
if asked {
found = Some(*row);
break;
}
}
});
found
}
/// Ask to be taken to the row of `name` that wants showing — now if its place
/// is known, and on the next frame if it is not.
///
/// A task that is already finished is not a wasted frame: iced takes its
/// message on the next pass of the loop, which is after this frame has been
/// laid out — and being laid out is exactly what the row has to have done for
/// there to be an answer.
fn reveal(name: String, row: i32, viewport: f32) -> Task<Message> {
match placements(&name).get(row) {
Some((top, height)) => {
let y = centred_offset(top, height, viewport);
if scroll_log() {
eprintln!(
"jolt-scroll: {name} row {row} at {top} (h {height}), viewport {viewport} -> {y}"
);
}
iced_scrollable::scroll_to(
scroll_id(&name),
AbsoluteOffset {
x: None,
y: Some(y),
},
)
}
None => {
if scroll_log() {
eprintln!("jolt-scroll: {name} row {row} has no place yet, trying again");
}
Task::future(async move { cosmic::Action::App(Message::Reveal(name, REVEAL_TRIES)) })
}
}
}
/// How many rows the scroll area called `name` has, and how many of them are
/// asking to be shown. For the log alone.
fn scroll_shape(t: &Tree, name: &str) -> (usize, usize) {
let mut shape = (0, 0);
walk(t, t.root_id(), &mut |id, n| {
if shape.0 > 0 || n.tag != "scroll" || scroll_name(n, id) != name {
return;
}
shape.0 = n.children.len();
for row in &n.children {
let mut asked = false;
walk(t, *row, &mut |_, node| {
asked |= node.bool("scroll-here") == Some(true);
});
if asked {
shape.1 += 1;
}
}
});
shape
}
fn snap_to_end(name: &str) -> Task<Message> {
iced_scrollable::snap_to(
scroll_id(name),
RelativeOffset {
x: None,
y: Some(1.0),
},
)
}
// --- the app -----------------------------------------------------------------
struct App {
core: Core,
tree: Arc<Tree>,
scrolls: HashMap<String, ScrollMemo>,
/// What the window last wrote back into a control, by node and prop, with
/// the sequence number of the event that carried it to the worker.
typed: HashMap<(i32, &'static str), (u64, Prop)>,
}
#[derive(Clone, Debug)]
enum Message {
Tree,
Quit,
Click(i32),
Toggled(i32, bool),
Change(i32, String),
Paste(i32, String),
PastedPicture(i32, Option<Vec<u8>>),
Activate(i32),
Hover(i32),
Unhover(i32),
Scrolled(i32, String, Viewport),
/// Show whichever row of this scroll area is asking to be shown, and how
/// many more frames to keep trying for. See `reveal`.
Reveal(String, u8),
/// Put this scroll area where it opened at — its end for `None`, that
/// offset for `Some` — again, and how many more frames to keep at it.
/// See `SETTLE_TRIES`.
Settle(String, Option<f32>, u8),
PickImage,
Picked(Option<PathBuf>),
}
/// Lay what was typed over a commit that has not caught up with it.
///
/// libcosmic paints a control from the tree, so a commit rendered before the
/// worker saw the latest keystroke would put the older text back under the
/// caret, and the next key would land on that. An entry is let go once a
/// commit was rendered after its event: from then on the component's own
/// state is the answer, a draft it cleared included.
fn keep_typed(
tree: &mut Arc<Tree>,
typed: &mut HashMap<(i32, &'static str), (u64, Prop)>,
settled: u64,
) {
typed.retain(|&(node, key), (seq, value)| {
let Some(n) = tree.get(node) else {
return false;
};
if *seq <= settled {
return false;
}
if n.props.get(key) != Some(value) {
Arc::make_mut(tree).set(node, key, value.clone());
}
true
});
}
impl App {
/// A widget does not own its value: the new state goes into the arena and
/// into what is painted, so a caller that ignores the event still sees a
/// working control, and its next render is what settles it. Then the event
/// goes to the worker, and what was written is held over any commit
/// rendered before the worker saw it.
fn write_back(
&mut self,
node: i32,
key: &'static str,
value: Prop,
event: &'static str,
text: String,
num: f64,
) {
edit(|t| t.set(node, key, value.clone()));
Arc::make_mut(&mut self.tree).set(node, key, value.clone());
let seq = post_seq(node, event, text, num);
self.typed.insert((node, key), (seq, value));
}
/// Take the committed tree, and move every scroll area to where it should
/// be now that it has changed.
///
/// A snap is relative, so a list snapped to its end stays at its end as
/// rows arrive under it, until the reader scrolls away.
fn take_tree(&mut self) -> Task<Message> {
let (committed, settled) = {
let c = lock(&COMMITTED);
(c.clone(), COMMITTED_SETTLED.load(SeqCst))
};
let before = std::mem::replace(&mut self.tree, committed);
keep_typed(&mut self.tree, &mut self.typed, settled);
let mut tasks = Vec::new();
let mut live = HashSet::new();
for ask in scroll_asks(&before, &self.tree) {
live.insert(ask.name.clone());
let memo = self.scrolls.entry(ask.name.clone()).or_insert(ScrollMemo {
at_end: ask.stick,
told: None,
offset_y: 0.0,
height: 0.0,
});
// A row asking to be shown is measured on the frame it appears,
// so the ask stands until the layout has a place for it — see
// `reveal`, which asks again rather than giving up.
let moved = scroll_move(&ask, memo);
match moved {
ScrollMove::Reveal(row) => tasks.push(reveal(ask.name.clone(), row, memo.height)),
ScrollMove::End => tasks.push(snap_to_end(&ask.name)),
ScrollMove::Restore(y) => tasks.push(iced_scrollable::scroll_to(
scroll_id(&ask.name),
AbsoluteOffset {
x: None,
y: Some(y),
},
)),
ScrollMove::Stay => {}
}
// And keeps asking, while this is the commit the list arrived on:
// there may be no widget to have heard the ask above. `reveal`
// does its own asking again; the other two are asked for here.
if ask.fresh {
let want = match moved {
ScrollMove::End => Some(None),
ScrollMove::Restore(y) => Some(Some(y)),
_ => None,
};
if let Some(want) = want {
let name = ask.name.clone();
tasks.push(Task::future(async move {
cosmic::Action::App(Message::Settle(name, want, SETTLE_TRIES))
}));
}
}
}
// A list that was never scrolled keeps no memo worth the space; one
// that was keeps its place for when it comes back.
self.scrolls
.retain(|name, memo| live.contains(name) || !memo.at_end || memo.offset_y > 0.0);
Task::batch(tasks)
}
fn scrolled(&mut self, node: i32, name: String, viewport: Viewport) {
let y = viewport.absolute_offset().y;
let room = viewport.content_bounds().height - viewport.bounds().height;
let at_end = room - y <= AT_END_SLACK;
let memo = self.scrolls.entry(name).or_insert(ScrollMemo {
at_end,
told: None,
offset_y: y,
height: viewport.bounds().height,
});
memo.at_end = at_end;
memo.offset_y = y;
memo.height = viewport.bounds().height;
if let Some(place) = report(memo, at_end) {
post(node, "change", place.to_owned(), 0.0);
}
}
}
impl cosmic::Application for App {
type Executor = cosmic::executor::Default;
type Flags = String;
type Message = Message;
const APP_ID: &'static str = "dev.jolt.Glimmer";
fn core(&self) -> &Core {
&self.core
}
fn core_mut(&mut self) -> &mut Core {
&mut self.core
}
fn init(core: Core, title: String) -> (Self, Task<Message>) {
let mut app = App {
core,
tree: lock(&COMMITTED).clone(),
scrolls: HashMap::new(),
typed: HashMap::new(),
};
// libcosmic's `wayland` feature brings `multi-window` with it, which
// makes a window title a per-window thing.
app.set_header_title(title.clone());
let task = match app.core.main_window_id() {
Some(id) => app.set_window_title(title, id),
None => Task::none(),
};
(app, task)
}
fn subscription(&self) -> Subscription<Message> {
Subscription::run(wakes)
}
fn on_window_resize(&mut self, _id: cosmic::iced::window::Id, width: f32, height: f32) {
WINDOW_W.store(width.max(0.0) as u32, SeqCst);
WINDOW_H.store(height.max(0.0) as u32, SeqCst);
}
fn update(&mut self, message: Message) -> Task<Message> {
match message {
Message::Tree => return self.take_tree(),
Message::Quit => return cosmic::iced::exit(),
Message::Click(node) => post(node, "click", String::new(), 0.0),
Message::Toggled(node, on) => {
let num = f64::from(u8::from(on));
self.write_back(
node,
"active",
Prop::Bool(on),
"toggled",
String::new(),
num,
);
}
Message::Change(node, text) => {
self.write_back(node, "text", Prop::Str(text.clone()), "change", text, 0.0);
}
// libcosmic's field answers Ctrl+V with the clipboard's text, and a
// clipboard holding a picture has none, so the field comes back as
// it was. That is the paste worth reporting: the picture is read
// here, where the clipboard is, and `paste-empty` goes to the
// worker, which collects it with `cosmic_clipboard_image_png`.
Message::Paste(node, text) => {
if self.tree.get(node).is_some_and(|n| n.str("text") == text) {
return cosmic::iced::clipboard::read_data::<ClipboardPng>().map(move |png| {
cosmic::Action::App(Message::PastedPicture(node, png.map(|p| p.0)))
});
}
self.write_back(node, "text", Prop::Str(text.clone()), "change", text, 0.0);
}
Message::PastedPicture(node, png) => {
*lock(&CLIPBOARD_PNG) = png;
post(node, "paste-empty", String::new(), 0.0);
}
Message::Activate(node) => post(node, "activate", String::new(), 0.0),
Message::Hover(node) => post(node, "hover", String::new(), 0.0),
Message::Unhover(node) => post(node, "unhover", String::new(), 0.0),
Message::Scrolled(node, name, viewport) => self.scrolled(node, name, viewport),
// The row was not laid out when the jump was asked for. Look
// again, and keep looking for a few frames: a room the reader has
// only just been taken to has to be built before its lines have
// anywhere to be.
// Asked again until the list says it arrived, or the budget is
// out. Idempotent either way: both asks name an absolute place,
// so one that already landed lands on the same place again.
Message::Settle(name, want, tries) => {
if settled(self.scrolls.get(&name), want) || tries == 0 {
return Task::none();
}
let again = {
let name = name.clone();
Task::future(async move {
cosmic::Action::App(Message::Settle(name, want, tries - 1))
})
};
let now = match want {
None => snap_to_end(&name),
Some(y) => iced_scrollable::scroll_to(
scroll_id(&name),
AbsoluteOffset {
x: None,
y: Some(y),
},
),
};
return Task::batch([now, again]);
}
Message::Reveal(name, tries) => {
let viewport = self.scrolls.get(&name).map_or(0.0, |memo| memo.height);
let place =
asking_row(&self.tree, &name).and_then(|row| placements(&name).get(row));
if let Some((top, height)) = place {
// Nothing written down here either, for the reason the
// commit path gives: where this ends up is `scrolled`'s to
// report, and its report is what the client hears.
let y = centred_offset(top, height, viewport);
return iced_scrollable::scroll_to(
scroll_id(&name),
AbsoluteOffset {
x: None,
y: Some(y),
},
);
}
if scroll_log() {
let asking = asking_row(&self.tree, &name);
let (rows, here) = scroll_shape(&self.tree, &name);
eprintln!(
"jolt-scroll: {name} retry {tries}, asking {asking:?}, \
{rows} rows, {here} asking to be shown, \
{} placed, viewport {viewport}",
placements(&name).len()
);
}
// Not landed yet. Keep trying for the whole budget rather
// than stopping the moment nothing is asking: a room the
// reader has just been taken to is built over several frames,
// and one where the rows are not in the tree yet looks exactly
// like a jump that is over. It is not over, it is early.
if tries > 0 {
return Task::future(async move {
cosmic::Action::App(Message::Reveal(name, tries - 1))
});
}
}
// The desktop's own chooser, through the portal, on libcosmic's
// executor: it is a D-Bus round trip, and the window keeps
// painting while it is open.
Message::PickImage => {
return Task::perform(
async {
rfd::AsyncFileDialog::new()
.set_title("Choose a picture")
.add_filter("Pictures", &["png", "jpg", "jpeg", "gif", "webp"])
.pick_file()
.await
.map(|file| file.path().to_path_buf())
},
|path| cosmic::Action::App(Message::Picked(path)),
);
}
Message::Picked(path) => *lock(&PICK) = path.map_or(Pick::Idle, Pick::Chosen),
}
Task::none()
}
fn view(&self) -> Element<'_, Message> {
let tree = &*self.tree;
let root = element(tree, tree.root_id(), true, false);
// A dialog that asked not to be modal, put up here rather than handed
// to `dialog` below. It is the same widget in the same place — a
// `popover` centres it exactly as `cosmic::app` does — and the whole
// of the difference is that this one is not told to intercept the
// pointer. That matters to anything the pointer opened: a modal
// popover hands the window underneath it a cursor that is
// `Unavailable`, so a face that opened a dialog on hover never hears
// the pointer leave, and what it opened can never close itself.
//
// The popover is here whether or not there is anything in it, which
// `cosmic::app` says of its own in one line and which this learned
// the long way: iced keeps a widget's state by where it sits in the
// tree, so a wrapper that comes and goes rebuilds everything under
// it — and what "everything" holds is the scroll positions. Wrapping
// only when a dialog appeared meant resting the pointer on a face
// jumped the conversation behind it.
let mut popover = widget::popover(root);
if let Some(id) = find_dialog(tree, false) {
// The dialog reports its own pointer, on the same two events a
// face or a pill reports theirs. Without it a dialog the pointer
// opened can only be read at arm's length: the client is told the
// pointer left what opened it and never told it arrived here, so
// the one way to keep it up is not to move — and everything in it
// is out of reach.
let popup = widget::mouse_area(dialog_of(tree, id))
.on_enter(Message::Hover(id))
.on_exit(Message::Unhover(id));
popover = popover.popup(popup);
}
popover.into()
}
/// The MODAL dialog the tree is carrying, if it is carrying one.
///
/// A client says there is one by putting a `dialog` node in the tree and
/// says there is not by leaving it out — the same way it says anything
/// else. What comes back is libcosmic's own dialog: centred, over a
/// dimmed window, and closed by the buttons the client hung on it.
///
/// A dialog that says `modal false` does not come back here. This hook is
/// the modal one whether the client wants it or not — `cosmic::app` wraps
/// whatever it returns in `popover(..).modal(true)` — and `view` puts
/// that kind up itself. See `dialog_of`.
fn dialog(&self) -> Option<Element<'_, Message>> {
let tree = &*self.tree;
let id = find_dialog(tree, true)?;
Some(dialog_of(tree, id))
}
}
/// The first `dialog` node in the tree whose modality is `modal`.
///
/// Absent, `modal` is true: a dialog is the modal kind unless it says it is
/// not, which is the shape everything else here takes — a prop left out is
/// the ordinary answer.
fn find_dialog(t: &Tree, modal: bool) -> Option<i32> {
let mut found = None;
walk(t, t.root_id(), &mut |id, n| {
if found.is_none() && n.tag == "dialog" && (n.bool("modal") != Some(false)) == modal {
found = Some(id);
}
});
found
}
/// One `dialog` node as libcosmic's dialog.
///
/// `label` is its heading and `body` the line under it. Children are its
/// controls, in order, except that a child carrying `slot` "primary" or
/// "secondary" becomes that action instead — which is where libcosmic puts
/// the buttons, at the foot and to the right.
fn dialog_of(t: &Tree, id: i32) -> Element<'_, Message> {
let Some(n) = t.get(id) else {
return widget::Space::new().width(0).height(0).into();
};
let mut d = widget::dialog();
if !n.label().is_empty() {
d = d.title(n.label().to_owned());
}
if !n.str("body").is_empty() {
d = d.body(n.str("body").to_owned());
}
if let Some(w) = n.num("max-width") {
d = d.max_width(w as f32);
}
for child in &n.children {
let Some(c) = t.get(*child) else { continue };
let el = element(t, *child, true, false);
d = match c.str("slot") {
"primary" => d.primary_action(el),
"secondary" => d.secondary_action(el),
_ => d.control(el),
};
}
d.into()
}
// --- props into layout -----------------------------------------------------------
/// `margin` all round, with `margin-top` and its siblings overriding a side.
fn margins(n: &Node) -> Padding {
let all = n.num("margin").unwrap_or(0.0) as f32;
let side = |key| n.num(key).map_or(all, |v| v as f32);
Padding {
top: side("margin-top"),
right: side("margin-right"),
bottom: side("margin-bottom"),
left: side("margin-left"),
}
}
/// A width the client asked for. Zero is the client saying "none": frq writes
/// `:width-request 0` on its message column whenever the people panel is shut,
/// and taken literally that is a backlog laid out zero points wide.
fn width_request(n: &Node) -> Option<f32> {
n.num("width-request")
.filter(|w| *w > 0.0)
.map(|w| w as f32)
}
/// `align`, or `default` where it is not set. A column starts its children at
/// the left. Rows do not ask: `align` on a row is where along the row its
/// children sit, not how they line up across it, and the row branch of
/// `element` reads it itself.
fn alignment(n: &Node, default: Alignment) -> Alignment {
match n.str("align") {
"start" => Alignment::Start,
"center" => Alignment::Center,
"end" => Alignment::End,
_ => default,
}
}
fn filled(color: Color, radius: f32) -> cosmic::theme::Container<'static> {
cosmic::theme::Container::custom(move |_| ContainerStyle {
background: Some(Background::Color(color)),
border: Border {
radius: radius.into(),
..Border::default()
},
text_color: Some(Color::WHITE),
..ContainerStyle::default()
})
}
/// A colour for somebody, from their name, so the same person is the same
/// colour everywhere they appear.
fn name_colour(name: &str) -> Color {
const PALETTE: [(f32, f32, f32); 8] = [
(0.83, 0.33, 0.33),
(0.85, 0.55, 0.20),
(0.62, 0.62, 0.18),
(0.30, 0.65, 0.35),
(0.20, 0.62, 0.62),
(0.30, 0.50, 0.85),
(0.55, 0.40, 0.85),
(0.80, 0.35, 0.65),
];
let hash = name
.bytes()
.fold(0u32, |h, b| h.wrapping_mul(31).wrapping_add(u32::from(b)));
let (r, g, b) = PALETTE[hash as usize % PALETTE.len()];
Color::from_rgb(r, g, b)
}
/// A picture that answers a click, with the pointer saying so.
fn clickable(el: Element<'_, Message>, id: i32, enabled: bool) -> Element<'_, Message> {
if !enabled {
return el;
}
widget::mouse_area(el)
.on_press(Message::Click(id))
.interaction(cosmic::iced::mouse::Interaction::Pointer)
.into()
}
fn picture(path: &str) -> Option<widget::image::Handle> {
(!path.is_empty() && std::path::Path::new(path).exists())
.then(|| widget::image::Handle::from_path(path))
}
// --- the tree into widgets ---------------------------------------------------------
/// One node and everything under it, as widgets.
///
/// `enabled` is inherited: an insensitive container takes its whole subtree out
/// of interaction. `in_row` is whether the parent lays its children out across:
/// a container fills its parent's CROSS axis, as it does in glimmer-jvui, so a
/// column in a column takes the width and a column in a row does not take the
/// row's slack unless it says `fill-height`.
fn element(t: &Tree, id: i32, enabled: bool, in_row: bool) -> Element<'_, Message> {
let Some(n) = t.get(id) else {
return Column::new().into();
};
let enabled = enabled && n.bool("sensitive") != Some(false);
let fill_height = n.bool("fill-height") == Some(true);
// glimmer-jvui's theme spacing, where the client does not say: a list of
// cards with nothing between them reads as one slab.
let spacing = n.num("spacing").unwrap_or(6.0) as f32;
let children = |row: bool| n.children.iter().map(move |c| element(t, *c, enabled, row));
let el: Element<'_, Message> = match n.tag.as_str() {
"window" => Column::with_children(children(false))
.width(Length::Fill)
.height(Length::Fill)
.into(),
// Sizes are set only where something asked for one. iced's rows and
// columns take `Fill` on an axis from any child that fills it, which is
// glimmer-jvui's `fills-height?` rule done for us — and an explicit
// `Shrink` would throw that away, so a wrapper with no `fill-height` of
// its own would hand the list inside it no height at all.
"box" => {
let across = n.str("orientation") == "horizontal";
if across {
// `align` on a row is the MAIN axis, which is glimmer's
// meaning and the one the shared screens are written against:
// `:end` lays the children out *from* the right, so the first
// child in the source is the rightmost on screen. Read as a
// cross-axis gravity instead it did nothing visible but sit
// the chips low, and the message heading's pair came out in
// the order ✏️ ↩️ 🙂 hard against the clock rather than the
// other way round against the edge — see `chat/action-chips`.
let from_end = n.str("align") == "end";
let mut row = if from_end {
Row::with_children(children(true).collect::<Vec<_>>().into_iter().rev())
} else {
Row::with_children(children(true))
}
.spacing(spacing)
.padding(margins(n))
// Across the row the children still centre: a chip beside a
// label sitting against the top of it is what that is for.
.align_y(Alignment::Center);
// A row fills the width it is in only when it or something in
// it asks to; otherwise a line of buttons would spread out.
match width_request(n) {
Some(w) => row = row.width(w),
None if fill_height => row = row.width(Length::Fill),
None => {}
}
if fill_height {
row = row.height(Length::Fill);
}
if from_end {
// iced has no main-axis alignment on a Row, so the edge is
// a container's doing: it takes the width and puts the row
// against the right of it. Not a leading Fill space, which
// would have halved the slack with a row that already has
// something filling in it — the join box beside its button
// is that row, and the box is meant to take all of it.
return widget::container(row)
.width(Length::Fill)
.align_x(Horizontal::Right)
.into();
}
row.into()
} else {
let mut column = Column::with_children(children(false))
.spacing(spacing)
.padding(margins(n))
.align_x(alignment(n, Alignment::Start));
match width_request(n) {
Some(w) => column = column.width(w),
None if fill_height || !in_row => column = column.width(Length::Fill),
None => {}
}
if fill_height {
column = column.height(Length::Fill);
}
column.into()
}
}
"page" => {
let column = Column::with_children(children(false))
.spacing(n.num("spacing").unwrap_or(8.0) as f32)
.padding(24)
.width(Length::Fill);
let mut inner = widget::container(column).width(Length::Fill);
if let Some(max) = n.num("max-width") {
inner = inner.max_width(max as f32);
}
widget::scrollable(widget::container(inner).center_x(Length::Fill))
.width(Length::Fill)
.height(Length::Fill)
.into()
}
"card" | "frame" => {
let mut column = Column::new().spacing(n.num("spacing").unwrap_or(8.0) as f32);
if n.tag == "frame" && !n.label().is_empty() {
column = column.push(widget::text::heading(n.label()));
}
let card = widget::container(column.extend(children(false)))
.padding(12)
.class(cosmic::theme::Container::Card);
match width_request(n) {
Some(w) => card.width(w).into(),
None if !in_row => card.width(Length::Fill).into(),
None => card.into(),
}
}
// Always fills both ways: a viewport that only fills its width asks its
// column for no height, and is given none. The content is held to its
// own height, since iced will not scroll content that fills the axis it
// scrolls along.
"scroll" => {
let name = scroll_name(n, id);
let content = Column::with_children(children(false))
.spacing(spacing)
.width(Length::Fill)
.height(Length::Shrink);
// Wrapped in the thing that writes down where each row landed, so
// that "take me to this line" has an answer in points — which is
// the only thing a scroll area can be told. See `rows`.
let content = rows::Rows::new(content, n.children.clone(), placements(&name));
widget::scrollable(content)
.id(scroll_id(&name))
.width(Length::Fill)
.height(Length::Fill)
.on_scroll(move |viewport| Message::Scrolled(id, name.clone(), viewport))
.into()
}
// Word wrapping that falls back to breaking inside a word: a URL is one
// word, and it otherwise runs straight past the edge of its column.
"label" if n.bool("dim") == Some(true) => widget::text::caption(n.label())
.wrapping(Wrapping::WordOrGlyph)
.into(),
"label" => widget::text::body(n.label())
.wrapping(Wrapping::WordOrGlyph)
.into(),
"title" => widget::text::title3(n.label())
.wrapping(Wrapping::WordOrGlyph)
.into(),
"title-2" => widget::text::title4(n.label())
.wrapping(Wrapping::WordOrGlyph)
.into(),
"dim-label" => widget::text::caption(n.label())
.wrapping(Wrapping::WordOrGlyph)
.into(),
"button" => {
let button = match n.str("kind") {
"primary" => widget::button::suggested(n.label()),
"destructive" => widget::button::destructive(n.label()),
_ => widget::button::standard(n.label()),
};
button
.on_press_maybe(enabled.then_some(Message::Click(id)))
.into()
}
"link" => widget::button::link(n.label().to_owned())
.on_press_maybe(enabled.then_some(Message::Click(id)))
.into(),
// A dot that says whether the thing is live, and the words beside it.
"status" => {
let colour = if n.bool("live") == Some(true) {
Color::from_rgb(0.30, 0.72, 0.40)
} else {
Color::from_rgb(0.55, 0.55, 0.55)
};
let dot = widget::container(widget::Space::new().width(8).height(8))
.class(filled(colour, 4.0));
Row::new()
.spacing(6)
.align_y(Alignment::Center)
.push(dot)
.push(widget::text::caption(n.label()))
.into()
}
"spinner" => {
let mut row = Row::new()
.spacing(8)
.align_y(Alignment::Center)
.push(widget::progress_bar::indeterminate_circular().size(16.0));
if !n.label().is_empty() {
row = row.push(widget::text::caption(n.label()));
}
row.into()
}
"emoji" => {
let glyph = match n.str("emoji") {
"" => n.label(),
e => e,
};
widget::text(glyph.to_owned())
.size(n.num("size").unwrap_or(16.0) as f32)
.font(EMOJI_FONT)
.into()
}
// A round picture, or the initial on a colour from the name: most
// people in most rooms have no picture, so the initial IS the avatar.
//
// And the three things a face is for besides being looked at. It
// painted as a picture and nothing else until now: a client that
// asked a face to answer a click, to report the pointer arriving, or
// to carry a card under it was handed a portrait that did none of
// them — so the profile behind every avatar in the window was
// unreachable, and the hover card written for it never appeared.
// Those are the same three things `reaction` below does, so they are
// done the same way: `mouse_area` for the press and the two edges of
// the hover, and a `tooltip` for whatever was hung underneath.
"avatar" => {
let size = n.num("size").unwrap_or(32.0) as f32;
let face: Element<'_, Message> = match picture(n.str("src")) {
Some(handle) => widget::image(handle)
.width(size)
.height(size)
.content_fit(ContentFit::Cover)
.border_radius(size / 2.0)
.into(),
None => {
let initial: String = n
.label()
.trim_start_matches(|c: char| !c.is_alphanumeric())
.chars()
.next()
.map(|c| c.to_uppercase().collect())
.unwrap_or_default();
widget::container(widget::text(initial).size(size * 0.45))
.center(Length::Fixed(size))
.class(filled(name_colour(n.label()), size / 2.0))
.into()
}
};
// The hover is reported whether or not the face is enabled: it
// says where the pointer is, which is true of an insensitive
// picture too. The press is not — an insensitive subtree is out
// of interaction, which is what `enabled` means here.
let mut area = widget::mouse_area(face)
.on_enter(Message::Hover(id))
.on_exit(Message::Unhover(id));
if enabled {
area = area
.on_press(Message::Click(id))
.interaction(cosmic::iced::mouse::Interaction::Pointer);
}
if n.children.is_empty() {
area.into()
} else {
widget::tooltip(
area,
Column::with_children(children(false)).spacing(4),
widget::tooltip::Position::Bottom,
)
.into()
}
}
// A pill: an emoji, how many people, and whether you are one of them.
// What the client hangs under it is its hover card, shown while the
// pointer is on the pill.
"reaction" => {
let glyph = match n.str("emoji") {
"" => n.label(),
e => e,
};
let size = n.num("size").unwrap_or(16.0) as f32;
let mut content = Row::new()
.spacing(4)
.align_y(Alignment::Center)
.push(widget::text(glyph.to_owned()).size(size).font(EMOJI_FONT));
let count = n.num("count").unwrap_or(0.0);
if count > 0.0 {
content = content.push(widget::text::caption(format!("{count}")));
}
let class = if n.bool("mine") == Some(true) {
widget::button::ButtonClass::Suggested
} else {
widget::button::ButtonClass::Standard
};
let pill = widget::button::custom(content)
.padding([2, 8])
.class(class)
.on_press_maybe(enabled.then_some(Message::Click(id)));
let pill = widget::mouse_area(pill)
.on_enter(Message::Hover(id))
.on_exit(Message::Unhover(id));
if n.children.is_empty() {
pill.into()
} else {
widget::tooltip(
pill,
Column::with_children(children(false)).spacing(4),
widget::tooltip::Position::Bottom,
)
.into()
}
}
// One tag for both kinds of picture, as in libvidya. `feed` is live
// pixels pushed under a name, which nothing pushes here yet, so it
// holds the slot the layout gave it.
"image" => {
let max_w = n.num("max-width").map(|v| v as f32);
let max_h = n.num("max-height").map(|v| v as f32);
if !n.str("feed").is_empty() {
let w = max_w.unwrap_or(160.0);
let h = max_h.unwrap_or(w * 0.75);
widget::container(widget::text::caption("video"))
.center_x(Length::Fixed(w))
.center_y(Length::Fixed(h))
.class(filled(Color::from_rgb(0.12, 0.12, 0.14), 8.0))
.into()
} else if let Some(handle) = picture(n.str("src")) {
let mut image = widget::image(handle).content_fit(ContentFit::Contain);
if n.bool("fit") == Some(true) {
image = image.width(Length::Fill).height(Length::Fill);
} else if let Some(size) = n.num("size") {
image = image.width(size as f32).height(size as f32);
}
let mut bounded = widget::container(image);
if let Some(w) = max_w {
bounded = bounded.max_width(w);
}
if let Some(h) = max_h {
bounded = bounded.max_height(h);
}
clickable(bounded.into(), id, enabled)
} else {
widget::Space::new().width(0).height(0).into()
}
}
"checkbutton" => {
let mut check = widget::checkbox(n.bool("active").unwrap_or(false)).label(n.label());
if enabled {
check = check.on_toggle(move |on| Message::Toggled(id, on));
}
check.into()
}
"entry" => {
let mut entry = widget::text_input(n.str("placeholder"), n.str("text"));
if enabled {
entry = entry
.on_input(move |text| Message::Change(id, text))
.on_paste(move |text| Message::Paste(id, text))
.on_submit(move |_| Message::Activate(id));
}
let width = match width_request(n) {
Some(w) if n.bool("hexpand") != Some(true) => Length::Fixed(w),
_ => Length::Fill,
};
entry.width(width).into()
}
"separator" => widget::divider::horizontal::default().into(),
"spacer" => {
let size = n.num("size").unwrap_or(8.0) as f32;
if n.str("expand").is_empty() {
widget::Space::new().width(size).height(size).into()
} else {
widget::Space::new().width(Length::Fill).height(size).into()
}
}
"progress" => {
let bar =
widget::progress_bar::determinate_linear(n.num("value").unwrap_or(0.0) as f32);
if n.label().is_empty() {
bar.into()
} else {
Column::new()
.spacing(4)
.push(widget::text::caption(n.label()))
.push(bar)
.into()
}
}
// The one node that is not painted where it stands. libcosmic puts a
// dialog up itself, centred over the window and dimming what is
// behind it — `Application::dialog` is the hook, and it is asked for
// one separately from `view`. So the tree carries the dialog wherever
// the client found it convenient to write it, `App::dialog` goes and
// finds it there, and this leaves nothing behind in the layout. A
// node rendered in both places would be painted twice.
"dialog" => widget::Space::new().width(0).height(0).into(),
// Kept rather than refused, as in libvidya: a tag this backend has not
// grown yet still shows its children.
_ => Column::with_children(children(false))
.spacing(spacing)
.padding(margins(n))
.into(),
};
// The containers and the entry size themselves above; anything else asked
// for a width gets it from a wrapper.
match (n.tag.as_str(), width_request(n)) {
("box" | "card" | "frame" | "entry" | "scroll" | "page" | "window", _) | (_, None) => el,
(_, Some(width)) => widget::container(el).width(width).into(),
}
}
// --- the C ABI: the loop -------------------------------------------------------
static TITLE: Mutex<String> = Mutex::new(String::new());
/// The window's title, read when `cosmic_run` opens it. A call of its own
/// because jolt will not pass a string to a `:blocking` foreign procedure, and
/// `cosmic_run` has to be one.
///
/// # Safety
/// `title` is null or a NUL-terminated string.
#[no_mangle]
pub unsafe extern "C" fn cosmic_set_title(title: *const c_char) {
let title = borrowed(title);
guard((), || *lock(&TITLE) = title)
}
/// Open the window and run libcosmic until it closes. Blocks; call it on the
/// process main thread. `mode` is 0 for the system theme, 1 dark, 2 light.
///
/// Answers 0 on a clean exit, 1 on an error, 2 when a window was already run
/// in this process — winit's event loop cannot be made twice.
#[no_mangle]
pub extern "C" fn cosmic_run(width: c_int, height: c_int, mode: c_int) -> c_int {
let status = guard(1, || {
let title = lock(&TITLE).clone();
if RAN.swap(true, SeqCst) {
log::error!("jolt-cosmic: a window already ran in this process");
return 2;
}
// The size asked for, until libcosmic reports the one it got.
WINDOW_W.store(width.max(1) as u32, SeqCst);
WINDOW_H.store(height.max(1) as u32, SeqCst);
let size = cosmic::iced::Size::new(width.max(1) as f32, height.max(1) as f32);
let mut settings = cosmic::app::Settings::default().size(size);
match mode {
1 => settings = settings.theme(cosmic::Theme::dark()),
2 => settings = settings.theme(cosmic::Theme::light()),
_ => {}
}
match cosmic::app::run::<App>(settings, title) {
Ok(()) => 0,
Err(err) => {
eprintln!("jolt-cosmic: {err}");
1
}
}
});
// Outside the guard, so a panic in libcosmic still releases the worker.
*lock(&TO_APP) = None;
CLOSED.store(true, SeqCst);
BELL.notify_all();
status
}
/// 1 once `cosmic_run` has returned.
#[no_mangle]
pub extern "C" fn cosmic_should_close() -> c_int {
c_int::from(CLOSED.load(SeqCst))
}
/// Close the window. Asked before the window exists, it closes on opening.
#[no_mangle]
pub extern "C" fn cosmic_quit() {
guard((), || {
QUIT_ASKED.store(true, SeqCst);
tell_app(Wake::Quit);
})
}
/// Publish the edits since the last commit. Answers 1 when there were any.
#[no_mangle]
pub extern "C" fn cosmic_tree_commit() -> c_int {
guard(0, || {
let settled = lock(&INBOX).settled;
let snapshot = {
let mut e = lock(&EDITS);
// A pass that only settled events still publishes, so a control
// holding typed text over an older commit lets go of it.
if !e.dirty && settled == COMMITTED_SETTLED.load(SeqCst) {
return 0;
}
e.dirty = false;
Arc::new(e.tree.clone())
};
{
let mut committed = lock(&COMMITTED);
*committed = snapshot;
COMMITTED_SETTLED.store(settled, SeqCst);
}
tell_app(Wake::Tree);
1
})
}
/// Block up to `timeout_ms` for an event, a `cosmic_wake`, or the window
/// closing. Answers 1 when an event is waiting.
#[no_mangle]
pub extern "C" fn cosmic_wait(timeout_ms: c_int) -> c_int {
guard(0, || {
let timeout = Duration::from_millis(timeout_ms.max(0) as u64);
let (mut inbox, _) = BELL
.wait_timeout_while(lock(&INBOX), timeout, |i| {
i.queue.is_empty() && !i.woken && !CLOSED.load(SeqCst)
})
.unwrap_or_else(|poisoned| poisoned.into_inner());
inbox.woken = false;
inbox.settled = inbox.taken;
c_int::from(!inbox.queue.is_empty())
})
}
/// Cut a `cosmic_wait` short — for work queued for the worker from elsewhere.
#[no_mangle]
pub extern "C" fn cosmic_wake() {
guard((), || {
lock(&INBOX).woken = true;
BELL.notify_all();
})
}
// --- the C ABI: the window and the desktop -----------------------------------------
/// The window's width in points; the size asked for until it has opened.
#[no_mangle]
pub extern "C" fn cosmic_window_width() -> c_int {
WINDOW_W.load(SeqCst) as c_int
}
#[no_mangle]
pub extern "C" fn cosmic_window_height() -> c_int {
WINDOW_H.load(SeqCst) as c_int
}
/// Open the desktop's picture chooser. Answers 1 when it was asked for, 0 when
/// there is no window to ask from; the choice arrives through
/// `cosmic_picked_image`.
#[no_mangle]
pub extern "C" fn cosmic_pick_image() -> c_int {
guard(0, || {
if lock(&TO_APP).is_none() {
return 0;
}
*lock(&PICK) = Pick::Open;
tell_app(Wake::PickImage);
1
})
}
/// Write the chosen picture to `path` as PNG. Answers 1 once, when a picture
/// was chosen since the last call; 0 while the chooser is open, after it was
/// cancelled, or when the picture could not be read.
///
/// # Safety
/// `path` is null or a NUL-terminated string.
#[no_mangle]
pub unsafe extern "C" fn cosmic_picked_image(path: *const c_char) -> c_int {
let path = borrowed(path);
guard(0, || {
let chosen = {
let mut pick = lock(&PICK);
match std::mem::replace(&mut *pick, Pick::Idle) {
Pick::Chosen(chosen) => chosen,
other => {
*pick = other;
return 0;
}
}
};
match image::open(&chosen)
.and_then(|picture| picture.save_with_format(&path, image::ImageFormat::Png))
{
Ok(()) => 1,
Err(err) => {
eprintln!("jolt-cosmic: could not take {}: {err}", chosen.display());
0
}
}
})
}
/// Write the picture the last empty Ctrl+V found on the clipboard to `path`.
/// Answers 1 when there was one; 0 when the clipboard held no PNG, when it was
/// already taken, or when the file could not be written.
///
/// # Safety
/// `path` is null or a NUL-terminated string.
#[no_mangle]
pub unsafe extern "C" fn cosmic_clipboard_image_png(path: *const c_char) -> c_int {
let path = borrowed(path);
guard(0, || {
let Some(png) = lock(&CLIPBOARD_PNG).take() else {
return 0;
};
match std::fs::write(&*path, png) {
Ok(()) => 1,
Err(err) => {
eprintln!("jolt-cosmic: could not write the pasted picture to {path}: {err}");
0
}
}
})
}
// --- the C ABI: events -----------------------------------------------------------
static EVENT_NAME: Scratch = Scratch::new();
static EVENT_TEXT: Scratch = Scratch::new();
/// Dequeue one event; 1 while there was one. The accessors describe it.
#[no_mangle]
pub extern "C" fn cosmic_tree_poll_event() -> c_int {
guard(0, || {
let mut inbox = lock(&INBOX);
let next = inbox.queue.pop_front();
let got = next.is_some();
if let Some(e) = &next {
inbox.taken = e.seq;
}
inbox.current = next;
c_int::from(got)
})
}
#[no_mangle]
pub extern "C" fn cosmic_tree_event_node() -> c_int {
guard(0, || lock(&INBOX).current.as_ref().map_or(0, |e| e.node))
}
#[no_mangle]
pub extern "C" fn cosmic_tree_event_name() -> *const c_char {
guard(empty_str(), || {
EVENT_NAME.lend(lock(&INBOX).current.as_ref().map_or("", |e| e.name))
})
}
#[no_mangle]
pub extern "C" fn cosmic_tree_event_text() -> *const c_char {
guard(empty_str(), || {
let text = lock(&INBOX)
.current
.as_ref()
.map(|e| e.text.clone())
.unwrap_or_default();
EVENT_TEXT.lend(text)
})
}
#[no_mangle]
pub extern "C" fn cosmic_tree_event_num() -> f64 {
guard(0.0, || lock(&INBOX).current.as_ref().map_or(0.0, |e| e.num))
}
// --- the C ABI: nodes --------------------------------------------------------------
static PROPS: Scratch = Scratch::new();
static DUMP: Scratch = Scratch::new();
#[no_mangle]
pub extern "C" fn cosmic_tree_root() -> c_int {
guard(0, || edit(Tree::root))
}
/// # Safety
/// `tag` is null or a NUL-terminated string.
#[no_mangle]
pub unsafe extern "C" fn cosmic_node_new(tag: *const c_char) -> c_int {
let tag = borrowed(tag);
guard(0, || edit(|t| t.new_node(&tag)))
}
#[no_mangle]
pub extern "C" fn cosmic_node_free(node: c_int) {
guard((), || edit(|t| t.free(node)))
}
#[no_mangle]
pub extern "C" fn cosmic_node_exists(node: c_int) -> c_int {
guard(0, || c_int::from(read(|t| t.exists(node))))
}
/// # Safety
/// `key` and `value` are null or NUL-terminated strings.
#[no_mangle]
pub unsafe extern "C" fn cosmic_node_set_str(
node: c_int,
key: *const c_char,
value: *const c_char,
) {
let (key, value) = (borrowed(key), borrowed(value));
guard((), || edit(|t| t.set(node, &key, Prop::Str(value))))
}
/// # Safety
/// `key` is null or a NUL-terminated string.
#[no_mangle]
pub unsafe extern "C" fn cosmic_node_set_num(node: c_int, key: *const c_char, value: f64) {
let key = borrowed(key);
guard((), || edit(|t| t.set(node, &key, Prop::Num(value))))
}
/// # Safety
/// `key` is null or a NUL-terminated string.
#[no_mangle]
pub unsafe extern "C" fn cosmic_node_set_bool(node: c_int, key: *const c_char, value: c_int) {
let key = borrowed(key);
guard((), || edit(|t| t.set(node, &key, Prop::Bool(value != 0))))
}
#[no_mangle]
pub extern "C" fn cosmic_node_clear_props(node: c_int) {
guard((), || edit(|t| t.clear_props(node)))
}
#[no_mangle]
pub extern "C" fn cosmic_node_tag(node: c_int) -> *const c_char {
guard(empty_str(), || {
PROPS.lend(read(|t| {
t.get(node).map(|n| n.tag.clone()).unwrap_or_default()
}))
})
}
#[no_mangle]
pub extern "C" fn cosmic_node_child_count(node: c_int) -> c_int {
guard(0, || {
read(|t| t.get(node).map_or(0, |n| n.children.len() as c_int))
})
}
#[no_mangle]
pub extern "C" fn cosmic_node_child_at(node: c_int, index: c_int) -> c_int {
guard(0, || {
read(|t| {
t.get(node)
.and_then(|n| n.children.get(usize::try_from(index).ok()?).copied())
.unwrap_or(0)
})
})
}
#[no_mangle]
pub extern "C" fn cosmic_node_append(parent: c_int, child: c_int) -> c_int {
guard(0, || c_int::from(edit(|t| t.append(parent, child))))
}
/// Unparents AND frees `child` with everything under it.
#[no_mangle]
pub extern "C" fn cosmic_node_remove(parent: c_int, child: c_int) {
guard((), || edit(|t| t.remove(parent, child)))
}
#[no_mangle]
pub extern "C" fn cosmic_node_insert_after(parent: c_int, child: c_int, sibling: c_int) -> c_int {
guard(0, || {
c_int::from(edit(|t| t.insert_after(parent, child, sibling)))
})
}
#[no_mangle]
pub extern "C" fn cosmic_node_replace(parent: c_int, old_child: c_int, new_child: c_int) -> c_int {
guard(0, || {
c_int::from(edit(|t| t.replace(parent, old_child, new_child)))
})
}
/// The subtree at `node` as hiccup; 0 is the root.
#[no_mangle]
pub extern "C" fn cosmic_tree_dump(node: c_int) -> *const c_char {
guard(empty_str(), || {
DUMP.lend(read(|t| {
let id = if node == 0 { t.root_id() } else { node };
t.dump(id)
}))
})
}
#[cfg(test)]
mod tests {
use super::*;
fn node(t: &mut Tree, parent: i32, tag: &str) -> i32 {
let id = t.new_node(tag);
assert!(t.append(parent, id));
id
}
#[test]
fn typed_text_stands_over_a_commit_that_has_not_seen_it() {
let mut t = Tree::default();
let root = t.root();
let entry = node(&mut t, root, "entry");
t.set(entry, "text", Prop::Str("a".into()));
let mut tree = Arc::new(t);
let mut typed = HashMap::new();
typed.insert((entry, "text"), (2, Prop::Str("ab".into())));
// Rendered before the worker saw the "b".
keep_typed(&mut tree, &mut typed, 1);
assert_eq!(tree.get(entry).unwrap().str("text"), "ab");
assert_eq!(typed.len(), 1);
// Rendered after: the component cleared its draft, and that stands.
Arc::make_mut(&mut tree).set(entry, "text", Prop::Str(String::new()));
keep_typed(&mut tree, &mut typed, 2);
assert_eq!(tree.get(entry).unwrap().str("text"), "");
assert!(typed.is_empty());
}
#[test]
fn a_zero_width_request_is_no_request() {
let mut t = Tree::default();
let root = t.root();
let column = node(&mut t, root, "vbox");
t.set(column, "width-request", Prop::Num(0.0));
assert_eq!(width_request(t.get(column).unwrap()), None);
t.set(column, "width-request", Prop::Num(260.0));
assert_eq!(width_request(t.get(column).unwrap()), Some(260.0));
}
#[test]
fn a_scroll_is_named_by_its_scroll_key() {
let mut t = Tree::default();
let root = t.root();
let list = node(&mut t, root, "scroll");
assert_eq!(
scroll_name(t.get(list).unwrap(), list),
format!("node-{list}")
);
t.set(list, "scroll-key", Prop::Str("messages-#freeq".into()));
assert_eq!(scroll_name(t.get(list).unwrap(), list), "messages-#freeq");
}
#[test]
fn a_row_is_centred_in_the_viewport_without_scrolling_past_the_top() {
// A row halfway down a long backlog, in a 600pt viewport: half the
// viewport above it, less half the row.
assert_eq!(centred_offset(1000.0, 40.0, 600.0), 1000.0 - 280.0);
// The same row with no viewport reported yet: its own top.
assert_eq!(centred_offset(1000.0, 40.0, 0.0), 1000.0);
// A row near the top cannot be centred without scrolling above the
// content, and nothing is above the content.
assert_eq!(centred_offset(20.0, 40.0, 600.0), 0.0);
// A row taller than the viewport is shown from its own top: there is
// no middle of it to put in the middle.
assert_eq!(centred_offset(500.0, 900.0, 600.0), 500.0);
}
#[test]
fn scroll_here_asks_with_its_row_and_goes_on_asking() {
let mut t = Tree::default();
let root = t.root();
let list = node(&mut t, root, "scroll");
t.set(list, "scroll-key", Prop::Str("backlog".into()));
let rows: Vec<i32> = (0..5).map(|_| node(&mut t, list, "vbox")).collect();
let before = t.clone();
t.set(rows[3], "scroll-here", Prop::Bool(true));
// The row, since a row is what has a place written down for it.
let asks = scroll_asks(&before, &t);
assert_eq!(asks.len(), 1);
assert!(!asks[0].fresh);
assert_eq!(asks[0].reveal, Some(rows[3]));
// And it goes on asking while the row is still asking: the row may not
// have been laid out on the commit the ask arrived.
let again = scroll_asks(&t, &t);
assert_eq!(again[0].reveal, Some(rows[3]));
// A node asking from deeper inside a row answers with the row.
t.set(rows[3], "scroll-here", Prop::Bool(false));
let inner = node(&mut t, rows[1], "vbox");
t.set(inner, "scroll-here", Prop::Bool(true));
assert_eq!(scroll_asks(&t, &t)[0].reveal, Some(rows[1]));
// Nothing asking, nothing to reveal.
t.set(inner, "scroll-here", Prop::Bool(false));
assert_eq!(scroll_asks(&t, &t)[0].reveal, None);
}
/// An ask for the scroll area called `name`, with nothing going on.
fn ask(name: &str) -> ScrollAsk {
ScrollAsk {
name: name.to_owned(),
stick: true,
tick: Some(0.0),
tick_before: Some(0.0),
fresh: false,
reveal: None,
}
}
fn memo() -> ScrollMemo {
ScrollMemo {
at_end: true,
told: Some(true),
offset_y: 0.0,
height: 600.0,
}
}
#[test]
fn a_jump_asks_for_the_end_without_saying_it_arrived() {
let mut m = memo();
m.at_end = false;
m.told = Some(false);
let mut a = ask("backlog");
a.tick = Some(1.0);
assert_eq!(scroll_move(&a, &mut m), ScrollMove::End);
// The memo still says what the last report said, so the report that
// comes back from the toolkit is a change, and is passed on. A memo
// that marked itself here would swallow it, and the client would go
// on believing the reader was away from the newest line.
assert!(!m.at_end);
assert_eq!(report(&mut m, true), Some("end"));
assert_eq!(report(&mut m, true), None);
}
#[test]
fn a_list_that_has_just_mounted_says_where_it_is() {
// The reader left this list away from the end, and the client was
// told so. It comes back — another room under the same widget, or the
// same room after the lightbox took the screen — and lands at the end
// because it sticks there. Nothing about `at_end` CHANGED across
// that, and the client still has to hear it: what it believes is
// about the list this one replaced.
let mut m = memo();
m.at_end = true;
m.told = Some(false);
let mut a = ask("backlog");
a.fresh = true;
assert_eq!(scroll_move(&a, &mut m), ScrollMove::End);
assert_eq!(report(&mut m, true), Some("end"));
}
#[test]
fn a_list_nobody_moved_is_not_reported_twice() {
let mut m = memo();
assert_eq!(report(&mut m, true), None);
assert_eq!(report(&mut m, false), Some("away"));
assert_eq!(report(&mut m, false), None);
assert_eq!(report(&mut m, true), Some("end"));
}
#[test]
fn a_row_asking_to_be_shown_beats_the_end() {
let mut m = memo();
let mut a = ask("backlog");
a.reveal = Some(42);
a.tick = Some(1.0);
assert_eq!(scroll_move(&a, &mut m), ScrollMove::Reveal(42));
}
#[test]
fn a_list_coming_back_is_put_where_it_was_left() {
let mut m = memo();
m.at_end = false;
m.offset_y = 512.0;
let mut a = ask("backlog");
a.fresh = true;
assert_eq!(scroll_move(&a, &mut m), ScrollMove::Restore(512.0));
// And it is asked about again, since the client's belief is about
// whatever was under this name before.
assert_eq!(m.told, None);
assert_eq!(report(&mut m, false), Some("away"));
}
#[test]
fn a_mount_keeps_asking_until_the_list_says_it_arrived() {
// Nothing heard from yet: the ask above may have found no widget to
// act on, so it stands.
assert!(!settled(None, None));
assert!(!settled(None, Some(512.0)));
// Reported somewhere else: still asking.
let mut m = memo();
m.at_end = false;
m.offset_y = 0.0;
assert!(!settled(Some(&m), None));
assert!(!settled(Some(&m), Some(512.0)));
// Arrived, and the asking stops.
m.at_end = true;
assert!(settled(Some(&m), None));
m.offset_y = 512.0;
assert!(settled(Some(&m), Some(512.0)));
// Within the slack a fractional offset leaves.
m.offset_y = 511.0;
assert!(settled(Some(&m), Some(512.0)));
m.offset_y = 480.0;
assert!(!settled(Some(&m), Some(512.0)));
}
#[test]
fn a_jump_is_the_counter_moving() {
let mut t = Tree::default();
let root = t.root();
let list = node(&mut t, root, "scroll");
t.set(list, "scroll-to-bottom", Prop::Num(1.0));
let before = t.clone();
t.set(list, "scroll-to-bottom", Prop::Num(2.0));
let asks = scroll_asks(&before, &t);
assert_eq!((asks[0].tick_before, asks[0].tick), (Some(1.0), Some(2.0)));
}
}
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