Checkpoint

crates/gpui2/src/app.rs

@@ -0,0 +1,527 @@
+mod async_context;
+mod entity_map;
+mod model_context;
+
+pub use async_context::*;
+pub use entity_map::*;
+pub use model_context::*;
+use refineable::Refineable;
+use smallvec::SmallVec;
+
+use crate::{
+    current_platform, image_cache::ImageCache, AssetSource, Context, DisplayId, Executor,
+    FocusEvent, FocusHandle, FocusId, KeyBinding, Keymap, LayoutId, MainThread, MainThreadOnly,
+    Platform, SubscriberSet, SvgRenderer, Task, TextStyle, TextStyleRefinement, TextSystem, View,
+    Window, WindowContext, WindowHandle, WindowId,
+};
+use anyhow::{anyhow, Result};
+use collections::{HashMap, HashSet, VecDeque};
+use futures::Future;
+use parking_lot::{Mutex, RwLock};
+use slotmap::SlotMap;
+use std::{
+    any::{type_name, Any, TypeId},
+    mem,
+    sync::{atomic::Ordering::SeqCst, Arc, Weak},
+};
+use util::http::{self, HttpClient};
+
+#[derive(Clone)]
+pub struct App(Arc<Mutex<AppContext>>);
+
+impl App {
+    pub fn production(asset_source: Arc<dyn AssetSource>) -> Self {
+        let http_client = http::client();
+        Self::new(current_platform(), asset_source, http_client)
+    }
+
+    #[cfg(any(test, feature = "test"))]
+    pub fn test() -> Self {
+        let platform = Arc::new(super::TestPlatform::new());
+        let asset_source = Arc::new(());
+        let http_client = util::http::FakeHttpClient::with_404_response();
+        Self::new(platform, asset_source, http_client)
+    }
+
+    fn new(
+        platform: Arc<dyn Platform>,
+        asset_source: Arc<dyn AssetSource>,
+        http_client: Arc<dyn HttpClient>,
+    ) -> Self {
+        let executor = platform.executor();
+        let entities = EntityMap::new();
+        let unit_entity = entities.insert(entities.reserve(), ());
+        Self(Arc::new_cyclic(|this| {
+            Mutex::new(AppContext {
+                this: this.clone(),
+                text_system: Arc::new(TextSystem::new(platform.text_system())),
+                pending_updates: 0,
+                flushing_effects: false,
+                next_frame_callbacks: Default::default(),
+                platform: MainThreadOnly::new(platform, executor.clone()),
+                executor,
+                svg_renderer: SvgRenderer::new(asset_source),
+                image_cache: ImageCache::new(http_client),
+                text_style_stack: Vec::new(),
+                global_stacks_by_type: HashMap::default(),
+                unit_entity,
+                entities,
+                windows: SlotMap::with_key(),
+                keymap: Arc::new(RwLock::new(Keymap::default())),
+                pending_notifications: Default::default(),
+                pending_effects: Default::default(),
+                observers: SubscriberSet::new(),
+                event_handlers: SubscriberSet::new(),
+                release_handlers: SubscriberSet::new(),
+                layout_id_buffer: Default::default(),
+            })
+        }))
+    }
+
+    pub fn run<F>(self, on_finish_launching: F)
+    where
+        F: 'static + FnOnce(&mut MainThread<AppContext>),
+    {
+        let this = self.clone();
+        let platform = self.0.lock().platform.clone();
+        platform.borrow_on_main_thread().run(Box::new(move || {
+            let cx = &mut *this.0.lock();
+            let cx = unsafe { mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(cx) };
+            on_finish_launching(cx);
+        }));
+    }
+}
+
+type Handler = Box<dyn Fn(&mut AppContext) -> bool + Send + Sync + 'static>;
+type EventHandler = Box<dyn Fn(&dyn Any, &mut AppContext) -> bool + Send + Sync + 'static>;
+type ReleaseHandler = Box<dyn Fn(&mut dyn Any, &mut AppContext) + Send + Sync + 'static>;
+type FrameCallback = Box<dyn FnOnce(&mut WindowContext) + Send>;
+
+pub struct AppContext {
+    this: Weak<Mutex<AppContext>>,
+    pub(crate) platform: MainThreadOnly<dyn Platform>,
+    text_system: Arc<TextSystem>,
+    flushing_effects: bool,
+    pending_updates: usize,
+    pub(crate) next_frame_callbacks: HashMap<DisplayId, Vec<FrameCallback>>,
+    pub(crate) executor: Executor,
+    pub(crate) svg_renderer: SvgRenderer,
+    pub(crate) image_cache: ImageCache,
+    pub(crate) text_style_stack: Vec<TextStyleRefinement>,
+    pub(crate) global_stacks_by_type: HashMap<TypeId, Vec<Box<dyn Any + Send + Sync>>>,
+    pub(crate) unit_entity: Handle<()>,
+    pub(crate) entities: EntityMap,
+    pub(crate) windows: SlotMap<WindowId, Option<Window>>,
+    pub(crate) keymap: Arc<RwLock<Keymap>>,
+    pub(crate) pending_notifications: HashSet<EntityId>,
+    pending_effects: VecDeque<Effect>,
+    pub(crate) observers: SubscriberSet<EntityId, Handler>,
+    pub(crate) event_handlers: SubscriberSet<EntityId, EventHandler>,
+    pub(crate) release_handlers: SubscriberSet<EntityId, ReleaseHandler>,
+    pub(crate) layout_id_buffer: Vec<LayoutId>, // We recycle this memory across layout requests.
+}
+
+impl AppContext {
+    pub(crate) fn update<R>(&mut self, update: impl FnOnce(&mut Self) -> R) -> R {
+        self.pending_updates += 1;
+        let result = update(self);
+        if !self.flushing_effects && self.pending_updates == 1 {
+            self.flushing_effects = true;
+            self.flush_effects();
+            self.flushing_effects = false;
+        }
+        self.pending_updates -= 1;
+        result
+    }
+
+    pub(crate) fn update_window<R>(
+        &mut self,
+        id: WindowId,
+        update: impl FnOnce(&mut WindowContext) -> R,
+    ) -> Result<R> {
+        self.update(|cx| {
+            let mut window = cx
+                .windows
+                .get_mut(id)
+                .ok_or_else(|| anyhow!("window not found"))?
+                .take()
+                .unwrap();
+
+            let result = update(&mut WindowContext::mutable(cx, &mut window));
+
+            cx.windows
+                .get_mut(id)
+                .ok_or_else(|| anyhow!("window not found"))?
+                .replace(window);
+
+            Ok(result)
+        })
+    }
+
+    pub(crate) fn push_effect(&mut self, effect: Effect) {
+        match &effect {
+            Effect::Notify { emitter } => {
+                if self.pending_notifications.insert(*emitter) {
+                    self.pending_effects.push_back(effect);
+                }
+            }
+            Effect::Emit { .. } => self.pending_effects.push_back(effect),
+            Effect::FocusChanged { .. } => self.pending_effects.push_back(effect),
+            Effect::Refresh => self.pending_effects.push_back(effect),
+        }
+    }
+
+    fn flush_effects(&mut self) {
+        loop {
+            self.release_dropped_entities();
+            self.release_dropped_focus_handles();
+            if let Some(effect) = self.pending_effects.pop_front() {
+                match effect {
+                    Effect::Notify { emitter } => self.apply_notify_effect(emitter),
+                    Effect::Emit { emitter, event } => self.apply_emit_effect(emitter, event),
+                    Effect::FocusChanged { window_id, focused } => {
+                        self.apply_focus_changed(window_id, focused)
+                    }
+                    Effect::Refresh => {
+                        self.apply_refresh();
+                    }
+                }
+            } else {
+                break;
+            }
+        }
+
+        let dirty_window_ids = self
+            .windows
+            .iter()
+            .filter_map(|(window_id, window)| {
+                let window = window.as_ref().unwrap();
+                if window.dirty {
+                    Some(window_id)
+                } else {
+                    None
+                }
+            })
+            .collect::<SmallVec<[_; 8]>>();
+
+        for dirty_window_id in dirty_window_ids {
+            self.update_window(dirty_window_id, |cx| cx.draw()).unwrap();
+        }
+    }
+
+    fn release_dropped_entities(&mut self) {
+        loop {
+            let dropped = self.entities.take_dropped();
+            if dropped.is_empty() {
+                break;
+            }
+
+            for (entity_id, mut entity) in dropped {
+                self.observers.remove(&entity_id);
+                self.event_handlers.remove(&entity_id);
+                for release_callback in self.release_handlers.remove(&entity_id) {
+                    release_callback(&mut entity, self);
+                }
+            }
+        }
+    }
+
+    fn release_dropped_focus_handles(&mut self) {
+        let window_ids = self.windows.keys().collect::<SmallVec<[_; 8]>>();
+        for window_id in window_ids {
+            self.update_window(window_id, |cx| {
+                let mut blur_window = false;
+                let focus = cx.window.focus;
+                cx.window.focus_handles.write().retain(|handle_id, count| {
+                    if count.load(SeqCst) == 0 {
+                        if focus == Some(handle_id) {
+                            blur_window = true;
+                        }
+                        false
+                    } else {
+                        true
+                    }
+                });
+
+                if blur_window {
+                    cx.blur();
+                }
+            })
+            .unwrap();
+        }
+    }
+
+    fn apply_notify_effect(&mut self, emitter: EntityId) {
+        self.pending_notifications.remove(&emitter);
+        self.observers
+            .clone()
+            .retain(&emitter, |handler| handler(self));
+    }
+
+    fn apply_emit_effect(&mut self, emitter: EntityId, event: Box<dyn Any>) {
+        self.event_handlers
+            .clone()
+            .retain(&emitter, |handler| handler(&event, self));
+    }
+
+    fn apply_focus_changed(&mut self, window_id: WindowId, focused: Option<FocusId>) {
+        self.update_window(window_id, |cx| {
+            if cx.window.focus == focused {
+                let mut listeners = mem::take(&mut cx.window.focus_listeners);
+                let focused =
+                    focused.map(|id| FocusHandle::for_id(id, &cx.window.focus_handles).unwrap());
+                let blurred = cx
+                    .window
+                    .last_blur
+                    .take()
+                    .unwrap()
+                    .and_then(|id| FocusHandle::for_id(id, &cx.window.focus_handles));
+                if focused.is_some() || blurred.is_some() {
+                    let event = FocusEvent { focused, blurred };
+                    for listener in &listeners {
+                        listener(&event, cx);
+                    }
+                }
+
+                listeners.extend(cx.window.focus_listeners.drain(..));
+                cx.window.focus_listeners = listeners;
+            }
+        })
+        .ok();
+    }
+
+    pub fn apply_refresh(&mut self) {
+        for window in self.windows.values_mut() {
+            if let Some(window) = window.as_mut() {
+                window.dirty = true;
+            }
+        }
+    }
+
+    pub fn to_async(&self) -> AsyncAppContext {
+        AsyncAppContext(unsafe { mem::transmute(self.this.clone()) })
+    }
+
+    pub fn executor(&self) -> &Executor {
+        &self.executor
+    }
+
+    pub fn run_on_main<R>(
+        &mut self,
+        f: impl FnOnce(&mut MainThread<AppContext>) -> R + Send + 'static,
+    ) -> Task<R>
+    where
+        R: Send + 'static,
+    {
+        if self.executor.is_main_thread() {
+            Task::ready(f(unsafe {
+                mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(self)
+            }))
+        } else {
+            let this = self.this.upgrade().unwrap();
+            self.executor.run_on_main(move || {
+                let cx = &mut *this.lock();
+                cx.update(|cx| f(unsafe { mem::transmute::<&mut Self, &mut MainThread<Self>>(cx) }))
+            })
+        }
+    }
+
+    pub fn spawn_on_main<F, R>(
+        &self,
+        f: impl FnOnce(&mut MainThread<AppContext>) -> F + Send + 'static,
+    ) -> Task<R>
+    where
+        F: Future<Output = R> + 'static,
+        R: Send + 'static,
+    {
+        let this = self.this.upgrade().unwrap();
+        self.executor.spawn_on_main(move || {
+            let cx = &mut *this.lock();
+            cx.update(|cx| {
+                f(unsafe { mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(cx) })
+            })
+        })
+    }
+
+    pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncAppContext) -> Fut + Send + 'static) -> Task<R>
+    where
+        Fut: Future<Output = R> + Send + 'static,
+        R: Send + 'static,
+    {
+        let cx = self.to_async();
+        self.executor.spawn(async move {
+            let future = f(cx);
+            future.await
+        })
+    }
+
+    pub fn text_system(&self) -> &Arc<TextSystem> {
+        &self.text_system
+    }
+
+    pub fn text_style(&self) -> TextStyle {
+        let mut style = TextStyle::default();
+        for refinement in &self.text_style_stack {
+            style.refine(refinement);
+        }
+        style
+    }
+
+    pub fn global<G: 'static>(&self) -> &G {
+        self.global_stacks_by_type
+            .get(&TypeId::of::<G>())
+            .and_then(|stack| stack.last())
+            .and_then(|any_state| any_state.downcast_ref::<G>())
+            .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
+            .unwrap()
+    }
+
+    pub fn global_mut<G: 'static>(&mut self) -> &mut G {
+        self.global_stacks_by_type
+            .get_mut(&TypeId::of::<G>())
+            .and_then(|stack| stack.last_mut())
+            .and_then(|any_state| any_state.downcast_mut::<G>())
+            .ok_or_else(|| anyhow!("no state of type {} exists", type_name::<G>()))
+            .unwrap()
+    }
+
+    pub fn default_global<G: 'static + Default + Sync + Send>(&mut self) -> &mut G {
+        let stack = self
+            .global_stacks_by_type
+            .entry(TypeId::of::<G>())
+            .or_default();
+        if stack.is_empty() {
+            stack.push(Box::new(G::default()));
+        }
+        stack.last_mut().unwrap().downcast_mut::<G>().unwrap()
+    }
+
+    pub(crate) fn push_global<T: Send + Sync + 'static>(&mut self, state: T) {
+        self.global_stacks_by_type
+            .entry(TypeId::of::<T>())
+            .or_default()
+            .push(Box::new(state));
+    }
+
+    pub(crate) fn pop_global<T: 'static>(&mut self) {
+        self.global_stacks_by_type
+            .get_mut(&TypeId::of::<T>())
+            .and_then(|stack| stack.pop())
+            .expect("state stack underflow");
+    }
+
+    pub(crate) fn push_text_style(&mut self, text_style: TextStyleRefinement) {
+        self.text_style_stack.push(text_style);
+    }
+
+    pub(crate) fn pop_text_style(&mut self) {
+        self.text_style_stack.pop();
+    }
+
+    pub fn bind_keys(&mut self, bindings: impl IntoIterator<Item = KeyBinding>) {
+        self.keymap.write().add_bindings(bindings);
+        self.push_effect(Effect::Refresh);
+    }
+}
+
+impl Context for AppContext {
+    type EntityContext<'a, 'w, T: Send + Sync + 'static> = ModelContext<'a, T>;
+    type Result<T> = T;
+
+    fn entity<T: Send + Sync + 'static>(
+        &mut self,
+        build_entity: impl FnOnce(&mut Self::EntityContext<'_, '_, T>) -> T,
+    ) -> Handle<T> {
+        self.update(|cx| {
+            let slot = cx.entities.reserve();
+            let entity = build_entity(&mut ModelContext::mutable(cx, slot.id));
+            cx.entities.insert(slot, entity)
+        })
+    }
+
+    fn update_entity<T: Send + Sync + 'static, R>(
+        &mut self,
+        handle: &Handle<T>,
+        update: impl FnOnce(&mut T, &mut Self::EntityContext<'_, '_, T>) -> R,
+    ) -> R {
+        self.update(|cx| {
+            let mut entity = cx.entities.lease(handle);
+            let result = update(&mut entity, &mut ModelContext::mutable(cx, handle.id));
+            cx.entities.end_lease(entity);
+            result
+        })
+    }
+}
+
+impl MainThread<AppContext> {
+    fn update<R>(&mut self, update: impl FnOnce(&mut Self) -> R) -> R {
+        self.0.update(|cx| {
+            update(unsafe {
+                std::mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(cx)
+            })
+        })
+    }
+
+    pub(crate) fn update_window<R>(
+        &mut self,
+        id: WindowId,
+        update: impl FnOnce(&mut MainThread<WindowContext>) -> R,
+    ) -> Result<R> {
+        self.0.update_window(id, |cx| {
+            update(unsafe {
+                std::mem::transmute::<&mut WindowContext, &mut MainThread<WindowContext>>(cx)
+            })
+        })
+    }
+
+    pub(crate) fn platform(&self) -> &dyn Platform {
+        self.platform.borrow_on_main_thread()
+    }
+
+    pub fn activate(&mut self, ignoring_other_apps: bool) {
+        self.platform().activate(ignoring_other_apps);
+    }
+
+    pub fn open_window<S: 'static + Send + Sync>(
+        &mut self,
+        options: crate::WindowOptions,
+        build_root_view: impl FnOnce(&mut WindowContext) -> View<S> + Send + 'static,
+    ) -> WindowHandle<S> {
+        self.update(|cx| {
+            let id = cx.windows.insert(None);
+            let handle = WindowHandle::new(id);
+            let mut window = Window::new(handle.into(), options, cx);
+            let root_view = build_root_view(&mut WindowContext::mutable(cx, &mut window));
+            window.root_view.replace(root_view.into_any());
+            cx.windows.get_mut(id).unwrap().replace(window);
+            handle
+        })
+    }
+}
+
+pub(crate) enum Effect {
+    Notify {
+        emitter: EntityId,
+    },
+    Emit {
+        emitter: EntityId,
+        event: Box<dyn Any + Send + Sync + 'static>,
+    },
+    FocusChanged {
+        window_id: WindowId,
+        focused: Option<FocusId>,
+    },
+    Refresh,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::AppContext;
+
+    #[test]
+    fn test_app_context_send_sync() {
+        // This will not compile if `AppContext` does not implement `Send`
+        fn assert_send<T: Send>() {}
+        assert_send::<AppContext>();
+    }
+}