diff --git a/crates/platform/README.md b/crates/platform/README.md --- a/crates/platform/README.md +++ b/crates/platform/README.md @@ -41,7 +41,9 @@ permission to discard work. Run those guards before `craft_quit::on_close_reques `appearance::Watcher` caches the desktop preference and wakes only on changes. Subscription precedes the first read. ReadOne/legacy Read, the standard namespace and GNOME fallback are handled together; -malformed values retain the last valid answer, and explicit no-preference clears it. Disconnection +on GNOME the "default" (Light) setting and portal value 0 read as light; elsewhere 0 is no preference. +Malformed values retain the last valid answer, and explicit no-preference clears it. +`Watcher::wait_first(timeout)` blocks until the first answer, a known absence, or the timeout (about 250 ms in an eframe creator), so the first frame uses the desktop theme. Disconnection retains the last valid value until a fresh answer. A later service owner triggers a reread; session reconnection has bounded backoff. Dropping cancels asynchronous work and waits at most 100 ms for acknowledgement, joining only an already-finished worker. A synchronously blocked OS call or caller wake callback can outlive diff --git a/crates/platform/src/appearance.rs b/crates/platform/src/appearance.rs --- a/crates/platform/src/appearance.rs +++ b/crates/platform/src/appearance.rs @@ -3,9 +3,12 @@ //! Derived from PdfCraft's activation-safe subscription and GNOME schema fallback, //! CADCraft's BSD support, and ArtCraft Launcher's ReadOne/Read compatibility. //! Palettes, manual choices and the fallback when no preference exists belong to the host. -use std::sync::{ - Arc, - atomic::{AtomicBool, AtomicU8, Ordering}, +use std::{ + sync::{ + Arc, Condvar, Mutex, PoisonError, + atomic::{AtomicBool, AtomicU8, Ordering}, + }, + time::Duration, }; /// Desktop color preference observed independently of the application palette. @@ -20,6 +23,12 @@ pub enum Theme { struct Shared { value: AtomicU8, active: AtomicBool, + /// True once the source has answered, found no answer, or been cancelled. + settled: Mutex, + settled_changed: Condvar, + /// `XDG_CURRENT_DESKTOP` names GNOME; read once when the watcher starts. + #[cfg(all(unix, not(target_os = "macos"), not(target_arch = "wasm32")))] + gnome: bool, #[cfg(all(unix, not(target_os = "macos"), not(target_arch = "wasm32")))] wake: Box, } @@ -32,13 +41,20 @@ impl Shared { } } #[cfg(all(unix, not(target_os = "macos"), not(target_arch = "wasm32")))] + fn settle(&self) { + *self.settled.lock().unwrap_or_else(PoisonError::into_inner) = true; + self.settled_changed.notify_all(); + } + #[cfg(all(unix, not(target_os = "macos"), not(target_arch = "wasm32")))] fn publish(&self, theme: Option) { let code = match theme { Some(Theme::Dark) => 1, Some(Theme::Light) => 2, None => 0, }; - if self.value.swap(code, Ordering::AcqRel) != code && self.active.load(Ordering::Acquire) { + let changed = self.value.swap(code, Ordering::AcqRel) != code; + self.settle(); + if changed && self.active.load(Ordering::Acquire) { (self.wake)(); } } @@ -81,6 +97,20 @@ impl Watcher { pub fn current(&self) -> Option { self.shared.get() } + /// Block until the first answer is known, then return it; at most `timeout`. + /// + /// Returns early, with `current()`, when the portal is absent and the `gsettings` fallback + /// found nothing, or when the desktop reports no preference. Call it once while building the + /// first frame so a light desktop does not flash dark: + /// + /// ```ignore + /// let theme = watcher.wait_first(std::time::Duration::from_millis(250)); + /// ``` + pub fn wait_first(&self, timeout: Duration) -> Option { + let settled = self.shared.settled.lock().unwrap_or_else(PoisonError::into_inner); + drop(self.shared.settled_changed.wait_timeout_while(settled, timeout, |settled| !*settled).unwrap_or_else(PoisonError::into_inner)); + self.current() + } /// Enable or suppress future change notifications without stopping observation. /// Changing this flag does not itself wake the host or clear the cached preference. pub fn set_active(&self, active: bool) { @@ -92,7 +122,15 @@ impl Watcher { wake: impl Fn() + Send + Sync + 'static, source: impl FnOnce(Arc) -> F + Send + 'static, ) -> Option { - let shared = Arc::new(Shared { value: AtomicU8::new(0), active: AtomicBool::new(active), wake: Box::new(wake) }); + let gnome = is_gnome(std::env::var("XDG_CURRENT_DESKTOP").ok().as_deref()); + let shared = Arc::new(Shared { + value: AtomicU8::new(0), + active: AtomicBool::new(active), + settled: Mutex::new(false), + settled_changed: Condvar::new(), + gnome, + wake: Box::new(wake), + }); let worker_shared = Arc::clone(&shared); let (stop, stopped) = async_channel::bounded::<()>(1); let (done, finished) = std::sync::mpsc::channel(); @@ -103,8 +141,9 @@ impl Watcher { async { let _ = stopped.recv().await; }, - source(worker_shared), + source(Arc::clone(&worker_shared)), )); + worker_shared.settle(); let _ = done.send(()); }) .ok()?; @@ -116,6 +155,7 @@ impl Drop for Watcher { self.set_active(false); #[cfg(all(unix, not(target_os = "macos"), not(target_arch = "wasm32")))] { + self.shared.settle(); self.stop.close(); if let Some(worker) = self.worker.take() { let _ = self.finished.recv_timeout(std::time::Duration::from_millis(100)); @@ -129,6 +169,12 @@ impl Drop for Watcher { } } +/// Whether a colon-separated `XDG_CURRENT_DESKTOP` value names GNOME. +#[cfg(all(unix, not(target_os = "macos"), not(target_arch = "wasm32")))] +fn is_gnome(desktop: Option<&str>) -> bool { + desktop.is_some_and(|list| list.split(':').any(|name| name.eq_ignore_ascii_case("gnome"))) +} + #[cfg(all(unix, not(target_os = "macos"), not(target_arch = "wasm32")))] mod portal { use super::{Shared, Theme}; @@ -144,27 +190,31 @@ mod portal { const TIMEOUT: Duration = Duration::from_secs(2); // Outer None means unknown/malformed; Some(None) is an explicit no-preference answer. - fn decode(namespace: &str, value: &Value<'_>) -> Option> { + // GNOME 42-46 writes 'default' (portal value 0) for Settings > Appearance > Light, so on GNOME + // both mean light; elsewhere both are no preference. + fn decode(namespace: &str, value: &Value<'_>, gnome: bool) -> Option> { match (namespace, value) { (STANDARD, Value::U32(n)) => Some(match n { 1 => Some(Theme::Dark), 2 => Some(Theme::Light), + 0 if gnome => Some(Theme::Light), _ => None, }), (GNOME, Value::Str(s)) => Some(match s.as_str() { "prefer-dark" => Some(Theme::Dark), "prefer-light" => Some(Theme::Light), + "default" if gnome => Some(Theme::Light), _ => None, }), _ => None, } } - fn reply(namespace: &str, value: &Value<'_>, legacy: bool) -> Option> { + fn reply(namespace: &str, value: &Value<'_>, legacy: bool, gnome: bool) -> Option> { if legacy { let Value::Value(inner) = value else { return None }; - decode(namespace, inner) + decode(namespace, inner, gnome) } else { - decode(namespace, value) + decode(namespace, value, gnome) } } fn combined(standard: Option>, gnome: Option>) -> Option> { @@ -177,11 +227,11 @@ mod portal { }) .await } - async fn read(connection: &zbus::Connection, namespace: &str) -> Option> { + async fn read(connection: &zbus::Connection, namespace: &str, gnome: bool) -> Option> { for (method, legacy) in [("ReadOne", false), ("Read", true)] { if let Some(Ok(message)) = bounded(connection.call_method(Some(DEST), PATH, Some(IFACE), method, &(namespace, KEY))).await && let Ok(value) = message.body().deserialize::() - && let Some(answer) = reply(namespace, &value, legacy) + && let Some(answer) = reply(namespace, &value, legacy, gnome) { return Some(answer); } @@ -213,6 +263,8 @@ mod portal { loop { let mut connected = false; let _ = session(&shared, &mut fallback_used, &mut connected).await; + // No session bus, no portal and an empty fallback all end here without a publish. + shared.settle(); if connected { retry = Duration::from_secs(5); } @@ -235,7 +287,7 @@ mod portal { && let Some(text) = crate::process::capture(&exe, &["get", GNOME, KEY], TIMEOUT).await { let text = text.trim().trim_matches('\''); - if let Some(answer) = decode(GNOME, &Value::from(text)) { + if let Some(answer) = decode(GNOME, &Value::from(text), shared.gnome) { shared.publish(answer); } } @@ -255,8 +307,8 @@ mod portal { // MatchRule installs before activation: unlike a proxy subscription it needs no current owner. let mut changes = bounded(zbus::MessageStream::for_match_rule(rule().ok()?, &connection, Some(64))).await?.ok()?; let mut owners = bounded(zbus::MessageStream::for_match_rule(owner_rule().ok()?, &connection, Some(8))).await?.ok()?; - let mut standard = read(&connection, STANDARD).await; - let mut gnome = read(&connection, GNOME).await; + let mut standard = read(&connection, STANDARD, shared.gnome).await; + let mut gnome = read(&connection, GNOME, shared.gnome).await; match combined(standard, gnome) { Some(answer) => { *connected = true; @@ -286,7 +338,7 @@ mod portal { if key != KEY { continue; } - let Some(answer) = decode(&namespace, &value) else { continue }; + let Some(answer) = decode(&namespace, &value, shared.gnome) else { continue }; match namespace.as_str() { STANDARD => standard = Some(answer), GNOME => gnome = Some(answer), @@ -323,6 +375,7 @@ mod portal { } use super::{GNOME, STANDARD, combined, decode, reply}; + use crate::appearance::is_gnome; use crate::appearance::{Theme, Watcher}; use std::{ sync::{Arc, atomic::Ordering}, @@ -339,18 +392,70 @@ mod portal { } #[test] fn malformed_is_distinct_from_no_preference_and_legacy_is_exact() { - assert_eq!(decode(STANDARD, &Value::U32(0)), Some(None)); - assert_eq!(decode(STANDARD, &Value::U32(77)), Some(None)); - assert_eq!(decode(STANDARD, &Value::from("dark")), None); - assert_eq!(reply(STANDARD, &Value::Value(Box::new(Value::U32(1))), true), Some(Some(Theme::Dark))); - assert_eq!(reply(STANDARD, &Value::U32(1), true), None); - assert_eq!(reply(STANDARD, &Value::Value(Box::new(Value::Value(Box::new(Value::U32(1))))), true), None); - assert_eq!(decode(STANDARD, &Value::Value(Box::new(Value::U32(1)))), None); - assert_eq!(decode(STANDARD, &Value::I32(1)), None); - assert_eq!(decode(GNOME, &Value::from("default")), Some(None)); - assert_eq!(decode(GNOME, &Value::U32(1)), None); - - assert_eq!(reply(GNOME, &Value::from("prefer-light"), false), Some(Some(Theme::Light))); + assert_eq!(decode(STANDARD, &Value::U32(0), false), Some(None)); + assert_eq!(decode(STANDARD, &Value::U32(77), false), Some(None)); + assert_eq!(decode(STANDARD, &Value::from("dark"), false), None); + assert_eq!(reply(STANDARD, &Value::Value(Box::new(Value::U32(1))), true, false), Some(Some(Theme::Dark))); + assert_eq!(reply(STANDARD, &Value::U32(1), true, false), None); + assert_eq!(reply(STANDARD, &Value::Value(Box::new(Value::Value(Box::new(Value::U32(1))))), true, false), None); + assert_eq!(decode(STANDARD, &Value::Value(Box::new(Value::U32(1))), false), None); + assert_eq!(decode(STANDARD, &Value::I32(1), false), None); + assert_eq!(decode(GNOME, &Value::U32(1), false), None); + assert_eq!(reply(GNOME, &Value::from("prefer-light"), false, false), Some(Some(Theme::Light))); + } + #[test] + fn gnome_light_setting_reads_as_light_and_zero_is_no_preference_elsewhere() { + assert_eq!(decode(GNOME, &Value::from("default"), true), Some(Some(Theme::Light))); + // A GNOME schema installed on another desktop doesn't make that desktop light. + assert_eq!(decode(GNOME, &Value::from("default"), false), Some(None)); + assert_eq!(decode(GNOME, &Value::from("prefer-dark"), false), Some(Some(Theme::Dark))); + assert_eq!(decode(GNOME, &Value::from("prefer-light"), false), Some(Some(Theme::Light))); + assert_eq!(decode(STANDARD, &Value::U32(0), true), Some(Some(Theme::Light))); + assert_eq!(decode(STANDARD, &Value::U32(0), false), Some(None)); + for gnome in [true, false] { + assert_eq!(decode(STANDARD, &Value::U32(1), gnome), Some(Some(Theme::Dark))); + assert_eq!(decode(STANDARD, &Value::U32(2), gnome), Some(Some(Theme::Light))); + } + assert!(is_gnome(Some("GNOME"))); + assert!(is_gnome(Some("ubuntu:GNOME"))); + assert!(is_gnome(Some("gnome-classic:gnome"))); + assert!(!is_gnome(Some("KDE"))); + assert!(!is_gnome(Some("X-Cinnamon"))); + assert!(!is_gnome(None)); + } + fn spawn_idle(source: impl FnOnce(Arc) + Send + 'static) -> Result { + Watcher::spawn(false, || {}, move |shared| async move { source(shared) }).ok_or("worker creation failed") + } + #[test] + fn wait_first_returns_at_once_after_a_publish() -> Result<(), Box> { + let watcher = spawn_idle(|shared| { + shared.publish(Some(Theme::Light)); + std::thread::sleep(Duration::from_millis(500)); + })?; + let started = std::time::Instant::now(); + assert_eq!(watcher.wait_first(Duration::from_secs(2)), Some(Theme::Light)); + assert!(started.elapsed() < Duration::from_secs(1)); + Ok(()) + } + #[test] + fn wait_first_times_out_without_an_answer_and_drop_stays_bounded() -> Result<(), Box> { + let watcher = Watcher::spawn(false, || {}, |_| futures_lite::future::pending::<()>()).ok_or("worker creation failed")?; + let started = std::time::Instant::now(); + assert_eq!(watcher.wait_first(Duration::from_millis(50)), None); + assert!(started.elapsed() >= Duration::from_millis(50)); + drop(watcher); + Ok(()) + } + #[test] + fn wait_first_returns_early_for_no_preference_and_for_a_source_that_ends_empty() -> Result<(), Box> { + let none = spawn_idle(|shared| shared.publish(None))?; + let ended = spawn_idle(|_| {})?; + for watcher in [none, ended] { + let started = std::time::Instant::now(); + assert_eq!(watcher.wait_first(Duration::from_secs(2)), None); + assert!(started.elapsed() < Duration::from_secs(1)); + } + Ok(()) } #[test] fn manual_cache_changes_do_not_wake_and_drop_cancels_pending_source() -> Result<(), Box> {