gpui-webview 0.8.1

extern crate gpui_kit as gpui;

#[cfg(all(feature = "gpui-fast", target_os = "macos"))]
mod composition;
#[cfg(target_os = "linux")]
mod linux;
#[cfg(target_os = "macos")]
mod macos;

#[cfg(all(feature = "gpui-fast", target_os = "macos"))]
use composition::NativeWebViewSurface;
#[cfg(all(feature = "gpui-fast", target_os = "linux"))]
use linux::NativeWebViewSurface;

use std::{cell::Cell, ops::Deref, rc::Rc};

use wry::Rect;

use gpui::{
    App, Bounds, ContentMask, DismissEvent, Element, ElementId, Entity, EventEmitter, FocusHandle,
    Focusable, GlobalElementId, Hitbox, InteractiveElement, IntoElement, LayoutId, MouseDownEvent,
    ParentElement as _, Pixels, Render, Size, Style, Styled as _, Window, canvas, div,
};

// `gpui-kit` selects the GPUI backend; this crate's `gpui-fast` feature only follows it, so
// the two must agree. A mismatch would otherwise keep the gpui-pre attachment on GPUI Fast.
const _: () = {
    assert!(
        !gpui::GPUI_FAST || cfg!(feature = "gpui-fast"),
        "gpui-kit is built with `gpui-fast`, but gpui-webview is not: enable the \
         `gpui-webview/gpui-fast` feature so the WebView uses GPUI Fast's window composition"
    );
    assert!(
        gpui::GPUI_FAST || !cfg!(feature = "gpui-fast"),
        "gpui-webview is built with `gpui-fast`, but gpui-kit is not: enable the \
         `gpui-kit/gpui-fast` feature, which selects the GPUI backend"
    );
};

/// An owned, UI-thread-local handle to the raw wry webview.
///
/// Cloning this handle prolongs the native webview's lifetime. Dropping the owning [`WebView`]
/// entity hides the child view, but final native destruction waits until all handle and frame
/// clones are dropped. All handles must be dropped before the parent window is destroyed.
#[derive(Clone)]
pub struct WebViewHandle(Rc<wry::WebView>);

impl WebViewHandle {
    /// Get the raw wry webview.
    pub fn raw(&self) -> &wry::WebView {
        &self.0
    }
}

/// A webview based on wry WebView.
///
/// With the `gpui-fast` feature, macOS and Linux host the native view in a window
/// composition surface, so deferred GPUI overlays render above the page. Without it, the
/// native view covers GPUI content in its bounds and extends past a container that clips it.
///
/// [experimental]
pub struct WebView {
    focus_handle: FocusHandle,
    webview: Rc<wry::WebView>,
    visible: Cell<bool>,
    bounds: Bounds<Pixels>,
    /// The page zoom the script asked for, before any display scale compensation.
    zoom: Cell<f64>,
    /// Whether the last geometry update failed, so each failure is logged once until it recovers.
    geometry_failed: Cell<bool>,
    #[cfg(all(feature = "gpui-fast", any(target_os = "macos", target_os = "linux")))]
    composition: Option<NativeWebViewSurface>,
    /// The GPUI scale factor the page zoom was last matched to.
    #[cfg(target_os = "linux")]
    scale_factor: Cell<f32>,
    /// The window-relative origin that page clicks are forwarded to GPUI from.
    #[cfg(target_os = "linux")]
    origin: Rc<Cell<gpui::Point<Pixels>>>,
}

impl Drop for WebView {
    fn drop(&mut self) {
        self.hide();
        #[cfg(all(feature = "gpui-fast", any(target_os = "macos", target_os = "linux")))]
        if let Some(surface) = self.composition.take() {
            surface.release(self.webview.clone());
        }
    }
}

impl WebView {
    /// Create a new WebView from a wry WebView.
    pub fn new(webview: wry::WebView, window: &mut Window, cx: &mut App) -> Self {
        let _ = webview.set_bounds(Rect::default());

        #[cfg(all(feature = "gpui-fast", target_os = "macos"))]
        let composition = match NativeWebViewSurface::new(&webview, window, cx) {
            Ok(surface) => Some(surface),
            Err(error) => {
                log::warn!("WebView composition unavailable: {error:#}");
                None
            }
        };
        #[cfg(target_os = "linux")]
        let origin = Rc::new(Cell::new(gpui::Point::default()));
        #[cfg(target_os = "linux")]
        linux::forward_mouse_down(&webview, origin.clone(), window, cx);
        #[cfg(target_os = "linux")]
        linux::match_scale_factor(&webview, window.scale_factor(), 1.0);
        #[cfg(not(any(all(feature = "gpui-fast", target_os = "macos"), target_os = "linux")))]
        let _ = window;

        Self {
            focus_handle: cx.focus_handle(),
            visible: Cell::new(true),
            bounds: Bounds::default(),
            zoom: Cell::new(1.0),
            geometry_failed: Cell::new(false),
            webview: Rc::new(webview),
            #[cfg(all(feature = "gpui-fast", target_os = "macos"))]
            composition,
            #[cfg(all(feature = "gpui-fast", target_os = "linux"))]
            composition: None,
            #[cfg(target_os = "linux")]
            scale_factor: Cell::new(window.scale_factor()),
            #[cfg(target_os = "linux")]
            origin,
        }
    }

    /// Build a webview as a child of `window`, performing the platform setup Wry requires.
    ///
    /// On Linux the window must run on X11 or XWayland: start the application with
    /// `gpui_kit::platform::linux(WindowingModes::X11)`. A Wayland window returns an error.
    /// This also initializes GTK and drives its main loop from GPUI. With the `gpui-fast` feature,
    /// the webview is built in a window composition surface so GPUI overlays can render above it.
    pub fn build(
        builder: wry::WebViewBuilder,
        window: &mut Window,
        cx: &mut App,
    ) -> wry::Result<Self> {
        #[cfg(target_os = "linux")]
        let webview = {
            let parent = linux::X11Parent::new(window)?;
            linux::ensure_gtk(cx)?;

            #[cfg(feature = "gpui-fast")]
            match NativeWebViewSurface::new(window, cx) {
                Ok(surface) => {
                    let webview = builder.build_as_child(&surface.parent()?)?;
                    let mut this = Self::new(webview, window, cx);
                    this.composition = Some(surface);
                    return Ok(this);
                }
                Err(error) => log::warn!("WebView composition unavailable: {error:#}"),
            }

            builder.build_as_child(&parent)?
        };
        #[cfg(not(target_os = "linux"))]
        let webview = builder.build_as_child(&*window)?;

        Ok(Self::new(webview, window, cx))
    }

    /// Set window-relative bounds, including offscreen loading bounds.
    /// With window composition, position the managed container and its child together.
    pub fn set_bounds(&self, bounds: Rect) -> wry::Result<()> {
        #[cfg(all(feature = "gpui-fast", any(target_os = "macos", target_os = "linux")))]
        if let Some(surface) = &self.composition {
            return surface
                .set_bounds(&self.webview, bounds)
                .map_err(|error| wry::Error::Io(std::io::Error::other(error)));
        }
        self.webview.set_bounds(bounds)
    }

    /// Apply full document bounds and an inherited clip without changing the DOM viewport.
    /// Empty clips hide the native surface while preserving the loaded document.
    /// Partial clipping requires native window composition; without it, the native view
    /// takes the full document bounds and extends past the clip.
    pub fn set_geometry(
        &self,
        document: Bounds<Pixels>,
        clip: Bounds<Pixels>,
    ) -> anyhow::Result<()> {
        let visible = document.intersect(&clip);
        if visible.is_empty() || !self.visible.get() {
            self.set_native_visible(false)?;
            #[cfg(all(feature = "gpui-fast", any(target_os = "macos", target_os = "linux")))]
            if let Some(surface) = &self.composition {
                // Hidden preparation still gives WebKit its real layout width.
                if self.visible.get() && !document.is_empty() {
                    surface.set_geometry(&self.webview, document, document)?;
                }
            }
            return Ok(());
        }
        #[cfg(all(feature = "gpui-fast", any(target_os = "macos", target_os = "linux")))]
        if let Some(surface) = &self.composition {
            surface.set_geometry(&self.webview, document, visible)?;
            surface.set_visible(true)?;
            self.webview.set_visible(true)?;
            return Ok(());
        }
        #[cfg(target_os = "linux")]
        let rect = linux::device_bounds(document, self.scale_factor.get());
        #[cfg(not(target_os = "linux"))]
        let rect = Rect {
            position: wry::dpi::LogicalPosition::new(
                f64::from(document.origin.x),
                f64::from(document.origin.y),
            )
            .into(),
            size: wry::dpi::LogicalSize::new(
                f64::from(document.size.width),
                f64::from(document.size.height),
            )
            .into(),
        };
        self.set_bounds(rect)?;
        self.set_native_visible(true)?;
        Ok(())
    }

    // Geometry can temporarily hide the native view without changing the caller's
    // visibility preference, so prepaint can retry when the view becomes unclipped.
    fn set_native_visible(&self, visible: bool) -> wry::Result<()> {
        self.webview.set_visible(visible)?;
        #[cfg(all(feature = "gpui-fast", any(target_os = "macos", target_os = "linux")))]
        if let Some(surface) = &self.composition {
            surface
                .set_visible(visible)
                .map_err(|error| wry::Error::Io(std::io::Error::other(error)))?;
        }
        Ok(())
    }

    /// Set visibility and report native errors without discarding the loaded page.
    pub fn set_visible(&self, visible: bool) -> wry::Result<()> {
        // A focus error must not leave a closing native view covering the window.
        let focus_result = if !visible && self.visible.get() {
            self.webview.focus_parent()
        } else {
            Ok(())
        };
        self.set_native_visible(visible)?;
        self.visible.set(visible);
        focus_result
    }

    /// Show the webview.
    pub fn show(&mut self) {
        let _ = self.set_visible(true);
    }

    /// Hide the webview.
    pub fn hide(&mut self) {
        let _ = self.set_visible(false);
    }

    /// Get whether the webview is visible.
    pub fn visible(&self) -> bool {
        self.visible.get()
    }

    /// Get the current bounds of the webview.
    pub fn bounds(&self) -> Bounds<Pixels> {
        self.bounds
    }

    /// Go back in the webview history.
    pub fn back(&mut self) -> anyhow::Result<()> {
        Ok(self.webview.evaluate_script("history.back();")?)
    }

    /// Go forward in the webview history.
    pub fn forward(&mut self) -> anyhow::Result<()> {
        Ok(self.webview.evaluate_script("history.forward();")?)
    }

    /// Load a URL in the webview.
    pub fn load_url(&mut self, url: &str) {
        let _ = self.webview.load_url(url);
    }

    /// Set the colour scheme the page sees in `prefers-color-scheme` and draws its
    /// native controls in. `Theme::Auto` follows the system again.
    ///
    /// On Linux this is GTK's process-wide `gtk-application-prefer-dark-theme`, so it
    /// applies to every webview in the application.
    pub fn set_theme(&self, theme: wry::Theme) -> wry::Result<()> {
        #[cfg(target_os = "linux")]
        linux::set_theme(theme);
        #[cfg(target_os = "macos")]
        macos::set_theme(&self.webview, theme);
        #[cfg(target_os = "windows")]
        wry::WebViewExtWindows::set_theme(&*self.webview, theme)?;
        #[cfg(not(any(target_os = "linux", target_os = "macos", target_os = "windows")))]
        let _ = theme;
        Ok(())
    }

    /// Zoom the page, where `1.0` is its natural size. The engine scales the page
    /// itself, without the relayout and repaint a CSS `zoom` causes, and keeps the
    /// factor across navigations.
    pub fn set_zoom(&self, zoom: f64) -> wry::Result<()> {
        self.zoom.set(zoom);
        // WebKitGTK's zoom also makes up for the gap between GPUI's scale factor and
        // GTK's integer one, so the page zoom is applied on top of it.
        #[cfg(target_os = "linux")]
        linux::match_scale_factor(&self.webview, self.scale_factor.get(), zoom);
        #[cfg(not(target_os = "linux"))]
        self.webview.zoom(zoom)?;
        Ok(())
    }

    /// The page zoom last set with [`WebView::set_zoom`].
    pub fn zoom(&self) -> f64 {
        self.zoom.get()
    }

    /// Get the raw wry webview.
    pub fn raw(&self) -> &wry::WebView {
        &self.webview
    }

    /// Get an owned, UI-thread-local handle to the raw wry webview.
    pub fn handle(&self) -> WebViewHandle {
        WebViewHandle(self.webview.clone())
    }
}

impl Deref for WebView {
    type Target = wry::WebView;

    fn deref(&self) -> &Self::Target {
        &self.webview
    }
}

impl Focusable for WebView {
    fn focus_handle(&self, _cx: &gpui::App) -> FocusHandle {
        self.focus_handle.clone()
    }
}

impl EventEmitter<DismissEvent> for WebView {}

impl Render for WebView {
    fn render(
        &mut self,
        window: &mut gpui::Window,
        cx: &mut gpui::Context<Self>,
    ) -> impl IntoElement {
        let view = cx.entity().clone();

        div()
            .track_focus(&self.focus_handle)
            .size_full()
            .child({
                let view = cx.entity().clone();
                canvas(
                    move |bounds, _, cx| view.update(cx, |r, _| r.bounds = bounds),
                    |_, _, _, _| {},
                )
                .absolute()
                .size_full()
            })
            .child(WebViewElement::new(self.webview.clone(), view, window, cx))
    }
}

/// A webview element can display a wry webview.
pub struct WebViewElement {
    parent: Entity<WebView>,
    view: Rc<wry::WebView>,
}

impl WebViewElement {
    /// Create a new webview element from a wry WebView.
    pub fn new(
        view: Rc<wry::WebView>,
        parent: Entity<WebView>,
        _window: &mut Window,
        _cx: &mut App,
    ) -> Self {
        Self { view, parent }
    }
}

impl IntoElement for WebViewElement {
    type Element = WebViewElement;

    fn into_element(self) -> Self::Element {
        self
    }
}

impl Element for WebViewElement {
    type RequestLayoutState = ();
    type PrepaintState = Option<Hitbox>;

    fn id(&self) -> Option<ElementId> {
        None
    }

    fn source_location(&self) -> Option<&'static std::panic::Location<'static>> {
        None
    }

    fn request_layout(
        &mut self,
        _: Option<&GlobalElementId>,
        _: Option<&gpui::InspectorElementId>,
        window: &mut Window,
        cx: &mut App,
    ) -> (LayoutId, Self::RequestLayoutState) {
        let style = Style {
            size: Size::full(),
            flex_shrink: 1.,
            ..Default::default()
        };

        // If the parent view is no longer visible, we don't need to layout the webview
        let id = window.request_layout(style, [], cx);
        (id, ())
    }

    fn prepaint(
        &mut self,
        _: Option<&GlobalElementId>,
        _: Option<&gpui::InspectorElementId>,
        bounds: Bounds<Pixels>,
        _: &mut Self::RequestLayoutState,
        window: &mut Window,
        cx: &mut App,
    ) -> Self::PrepaintState {
        if !self.parent.read(cx).visible() {
            return None;
        }

        let parent = self.parent.read(cx);
        #[cfg(all(feature = "gpui-fast", any(target_os = "macos", target_os = "linux")))]
        if let Some(surface) = &parent.composition {
            surface.set_scale_factor(window.scale_factor());
        }
        #[cfg(target_os = "linux")]
        if parent.scale_factor.replace(window.scale_factor()) != window.scale_factor() {
            linux::match_scale_factor(&parent.webview, window.scale_factor(), parent.zoom.get());
        }
        #[cfg(target_os = "linux")]
        parent.origin.set(bounds.origin);
        let clip = window.content_mask().bounds;
        if let Err(error) = parent.set_geometry(bounds, clip) {
            if !parent.geometry_failed.replace(true) {
                log::warn!("WebView geometry update failed: {error:#}");
            }
            let _ = parent.set_native_visible(false);
            return None;
        }
        parent.geometry_failed.set(false);
        let visible = bounds.intersect(&clip);
        if visible.is_empty() {
            return None;
        }

        // The native view covers this area, so GPUI content below it must not receive input.
        Some(window.insert_hitbox(visible, gpui::HitboxBehavior::BlockMouse))
    }

    fn paint(
        &mut self,
        _: Option<&GlobalElementId>,
        _: Option<&gpui::InspectorElementId>,
        bounds: Bounds<Pixels>,
        _: &mut Self::RequestLayoutState,
        hitbox: &mut Self::PrepaintState,
        window: &mut Window,
        _: &mut App,
    ) {
        let bounds = hitbox.clone().map(|h| h.bounds).unwrap_or(bounds);
        window.with_content_mask(Some(ContentMask { bounds }), |window| {
            let webview = self.view.clone();
            window.on_mouse_event(move |event: &MouseDownEvent, _, _, _| {
                if !bounds.contains(&event.position) {
                    // Click white space to blur the input focus
                    let _ = webview.focus_parent();
                }
            });
        });
    }
}