Add the ability to follow links

apps/readme/src/main.rs

@@ -3,6 +3,7 @@ mod readme_application;
 
 use blitz_html::HtmlDocument;
 use blitz_net::Provider;
+use blitz_traits::navigation::NavigationProvider;
 use markdown::{markdown_to_html, BLITZ_MD_STYLES, GITHUB_MD_STYLES};
 use notify::{Error as NotifyError, Event as NotifyEvent, RecursiveMode, Watcher as _};
 use readme_application::{ReadmeApplication, ReadmeEvent};
@@ -14,9 +15,21 @@ use std::fs;
 use std::path::{Path, PathBuf};
 use std::sync::Arc;
 use url::Url;
+use winit::event_loop::EventLoopProxy;
 use winit::window::WindowAttributes;
 
 const USER_AGENT: &str = "Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Firefox/81.0";
+
+struct ReadmeNavigationProvider {
+    proxy: EventLoopProxy<BlitzEvent>,
+}
+
+impl NavigationProvider for ReadmeNavigationProvider {
+    fn navigate_new_page(&self, url: String) {
+        let _ = self.proxy.send_event(BlitzEvent::Navigate(url));
+    }
+}
+
 fn main() {
     let raw_url = std::env::args().nth(1).unwrap_or_else(|| {
         let cwd = current_dir().unwrap();
@@ -55,19 +68,30 @@ fn main() {
     let net_callback = BlitzShellNetCallback::shared(proxy.clone());
     let net_provider = Provider::shared(net_callback);
 
+    let proxy = event_loop.create_proxy();
+    let navigation_provider = ReadmeNavigationProvider {
+        proxy: proxy.clone(),
+    };
+    let navigation_provider = Arc::new(navigation_provider);
+
     let doc = HtmlDocument::from_html(
         &html,
         Some(base_url),
         stylesheets,
         net_provider.clone(),
         None,
+        navigation_provider.clone(),
     );
     let attrs = WindowAttributes::default().with_title(title);
     let window = WindowConfig::with_attributes(doc, attrs);
 
     // Create application
-    let mut application =
-        ReadmeApplication::new(event_loop.create_proxy(), raw_url.clone(), net_provider);
+    let mut application = ReadmeApplication::new(
+        proxy.clone(),
+        raw_url.clone(),
+        net_provider,
+        navigation_provider,
+    );
     application.add_window(window);
 
     if let Some(path) = file_path {

apps/readme/src/readme_application.rs

@@ -4,6 +4,7 @@ use blitz_dom::net::Resource;
 use blitz_html::HtmlDocument;
 use blitz_renderer_vello::BlitzVelloRenderer;
 use blitz_shell::{BlitzApplication, BlitzEvent, View, WindowConfig};
+use blitz_traits::navigation::NavigationProvider;
 use blitz_traits::net::NetProvider;
 use tokio::runtime::Handle;
 use winit::application::ApplicationHandler;
@@ -23,13 +24,15 @@ pub struct ReadmeApplication {
     net_provider: Arc<dyn NetProvider<Data = Resource>>,
     raw_url: String,
     keyboard_modifiers: Modifiers,
+    navigation_provider: Arc<dyn NavigationProvider>,
 }
 
 impl ReadmeApplication {
     pub fn new(
         proxy: EventLoopProxy<BlitzEvent>,
         raw_url: String,
         net_provider: Arc<dyn NetProvider<Data = Resource>>,
+        navigation_provider: Arc<dyn NavigationProvider>,
     ) -> Self {
         let handle = Handle::current();
         Self {
@@ -38,6 +41,7 @@ impl ReadmeApplication {
             raw_url,
             net_provider,
             keyboard_modifiers: Default::default(),
+            navigation_provider,
         }
     }
 
@@ -66,6 +70,7 @@ impl ReadmeApplication {
             stylesheets,
             self.net_provider.clone(),
             None,
+            self.navigation_provider.clone(),
         );
         self.window_mut().replace_document(doc);
     }
@@ -124,6 +129,10 @@ impl ApplicationHandler<BlitzEvent> for ReadmeApplication {
                     self.reload_document();
                 }
             }
+            BlitzEvent::Navigate(url) => {
+                self.raw_url = url;
+                self.reload_document();
+            }
             event => self.inner.user_event(event_loop, event),
         }
     }

apps/wpt/src/attr_test.rs

@@ -40,6 +40,7 @@ pub async fn parse_and_resolve_document(
         Vec::new(),
         Arc::clone(&ctx.net_provider) as SharedProvider<Resource>,
         Some(clone_font_ctx(&ctx.font_ctx)),
+        ctx.navigation_provider.clone(),
     );
 
     document.as_mut().set_viewport(ctx.viewport.clone());

apps/wpt/src/main.rs

@@ -1,5 +1,6 @@
 use blitz_dom::net::Resource;
 use blitz_renderer_vello::VelloImageRenderer;
+use blitz_traits::navigation::{DummyNavigationProvider, NavigationProvider};
 use blitz_traits::{ColorScheme, Viewport};
 use parley::FontContext;
 use pollster::FutureExt as _;
@@ -170,6 +171,7 @@ impl Buffers {
 struct ThreadCtx {
     viewport: Viewport,
     net_provider: Arc<WptNetProvider<Resource>>,
+    navigation_provider: Arc<dyn NavigationProvider>,
     renderer: VelloImageRenderer,
     font_ctx: FontContext,
     buffers: Buffers,
@@ -327,6 +329,7 @@ fn main() {
                             .unwrap();
 
                     let dummy_base_url = Url::parse("http://dummy.local").unwrap();
+                    let navigation_provider = Arc::new(DummyNavigationProvider);
 
                     RefCell::new(ThreadCtx {
                         viewport,
@@ -349,6 +352,7 @@ fn main() {
                         out_dir: out_dir.clone(),
                         wpt_dir: wpt_dir.clone(),
                         dummy_base_url,
+                        navigation_provider,
                     })
                 })
                 .borrow_mut();

apps/wpt/src/ref_test.rs

@@ -111,6 +111,7 @@ async fn render_html_to_buffer(
         Vec::new(),
         Arc::clone(&ctx.net_provider) as SharedProvider<Resource>,
         Some(clone_font_ctx(&ctx.font_ctx)),
+        ctx.navigation_provider.clone(),
     );
 
     document.as_mut().set_viewport(ctx.viewport.clone());

packages/blitz-dom/src/document.rs

@@ -5,6 +5,7 @@ use crate::stylo_to_cursor_icon::stylo_to_cursor_icon;
 use crate::util::ImageType;
 use crate::{ElementNodeData, Node, NodeData, TextNodeData};
 use app_units::Au;
+use blitz_traits::navigation::{DummyNavigationProvider, NavigationProvider};
 use blitz_traits::net::{DummyNetProvider, SharedProvider};
 use blitz_traits::{ColorScheme, Viewport};
 use cursor_icon::CursorIcon;
@@ -145,6 +146,10 @@ pub struct Document {
 
     /// Network provider. Can be used to fetch assets.
     pub net_provider: SharedProvider<Resource>,
+
+    /// Navigation provider. Can be used to navigate to a new page (bubbles up the event
+    /// on e.g. clicking a Link)
+    pub navigation_provider: Arc<dyn NavigationProvider>,
 }
 
 fn make_device(viewport: &Viewport) -> Device {
@@ -222,6 +227,13 @@ impl DocumentLike for Document {
                             }
                             self.set_focus_to(node_id);
                         }
+                    } else if el.name.local == local_name!("a") {
+                        if let Some(href) = el.attr(local_name!("href")) {
+                            let url = resolve_url(&self.base_url, href);
+                            self.navigation_provider.navigate_new_page(url.into());
+                        } else {
+                            println!("Clicked link without href: {:?}", el.attrs());
+                        }
                     }
                 }
             }
@@ -331,6 +343,7 @@ impl Document {
             focus_node_id: None,
             changed: HashSet::new(),
             net_provider: Arc::new(DummyNetProvider::default()),
+            navigation_provider: Arc::new(DummyNavigationProvider {}),
         };
 
         // Initialise document with root Document node
@@ -357,6 +370,11 @@ impl Document {
         self.net_provider = net_provider;
     }
 
+    /// Set the Document's navigation provider
+    pub fn set_navigation_provider(&mut self, navigation_provider: Arc<dyn NavigationProvider>) {
+        self.navigation_provider = navigation_provider;
+    }
+
     /// Set base url for resolving linked resources (stylesheets, images, fonts, etc)
     pub fn set_base_url(&mut self, url: &str) {
         self.base_url = Some(Url::parse(url).unwrap());
@@ -586,10 +604,7 @@ impl Document {
     }
 
     pub fn resolve_url(&self, raw: &str) -> url::Url {
-        match &self.base_url {
-            Some(base_url) => base_url.join(raw).unwrap(),
-            None => url::Url::parse(raw).unwrap(),
-        }
+        resolve_url(&self.base_url, raw)
     }
 
     pub fn print_tree(&self) {
@@ -1224,3 +1239,12 @@ impl AsMut<Document> for Document {
         self
     }
 }
+
+fn resolve_url(base_url: &Option<url::Url>, raw: &str) -> url::Url {
+    // TODO: this will bite use eventually. You can be sure on the www there is a myriad of links that
+    // cannot be parsed.
+    match base_url {
+        Some(base_url) => base_url.join(raw).unwrap(),
+        None => url::Url::parse(raw).unwrap(),
+    }
+}

packages/blitz-html/src/html_document.rs

@@ -1,9 +1,11 @@
+use std::sync::Arc;
+
 use crate::DocumentHtmlParser;
 
 use blitz_dom::{
     events::RendererEvent, net::Resource, Document, DocumentLike, FontContext, DEFAULT_CSS,
 };
-use blitz_traits::{net::SharedProvider, ColorScheme, Viewport};
+use blitz_traits::{navigation::NavigationProvider, net::SharedProvider, ColorScheme, Viewport};
 
 pub struct HtmlDocument {
     inner: Document,
@@ -28,7 +30,7 @@ impl From<HtmlDocument> for Document {
 }
 impl DocumentLike for HtmlDocument {
     fn handle_event(&mut self, event: RendererEvent) {
-        self.inner.as_mut().handle_event(event);
+        self.inner.as_mut().handle_event(event)
     }
 }
 
@@ -39,6 +41,7 @@ impl HtmlDocument {
         stylesheets: Vec<String>,
         net_provider: SharedProvider<Resource>,
         font_ctx: Option<FontContext>,
+        navigation_provider: Arc<dyn NavigationProvider>,
     ) -> Self {
         // Spin up the virtualdom and include the default stylesheet
         let viewport = Viewport::new(0, 0, 1.0, ColorScheme::Light);
@@ -55,6 +58,9 @@ impl HtmlDocument {
         // Set the net provider
         doc.set_net_provider(net_provider.clone());
 
+        // Set the navigation provider
+        doc.set_navigation_provider(navigation_provider.clone());
+
         // Include default and user-specified stylesheets
         doc.add_user_agent_stylesheet(DEFAULT_CSS);
         for ss in &stylesheets {

packages/blitz-shell/src/application.rs

@@ -132,6 +132,9 @@ impl<Doc: DocumentLike, Rend: DocumentRenderer> ApplicationHandler<BlitzEvent>
             BlitzEvent::Embedder(_) => {
                 // Do nothing. Should be handled by embedders (if required).
             }
+            BlitzEvent::Navigate(_url) => {
+                // Do nothing. Should be handled by embedders (if required).
+            }
         }
     }
 }

packages/blitz-shell/src/event.rs

@@ -26,6 +26,9 @@ pub enum BlitzEvent {
 
     /// An arbitary event from the Blitz embedder
     Embedder(Arc<dyn Any + Send + Sync>),
+
+    /// Navigate to another URL (triggered by e.g. clicking a link)
+    Navigate(String),
 }
 impl BlitzEvent {
     pub fn embedder_event<T: Any + Send + Sync>(value: T) -> Self {

packages/blitz-traits/src/lib.rs

@@ -1,5 +1,7 @@
 pub mod net;
 
+pub mod navigation;
+
 mod devtools;
 pub use devtools::Devtools;
 

packages/blitz-traits/src/navigation.rs

@@ -0,0 +1,12 @@
+/// A provider to enable a document to bubble up navigation events (e.g. clicking a link)
+pub trait NavigationProvider: Send + Sync + 'static {
+    fn navigate_new_page(&self, url: String);
+}
+
+pub struct DummyNavigationProvider;
+
+impl NavigationProvider for DummyNavigationProvider {
+    fn navigate_new_page(&self, _url: String) {
+        // Default impl: do nothing
+    }
+}

packages/blitz/Cargo.toml

@@ -18,6 +18,7 @@ blitz-renderer-vello = { path = "../blitz-renderer-vello" }
 blitz-html = { path = "../blitz-html" }
 blitz-shell = { path = "../blitz-shell" }
 blitz-net = { path = "../blitz-net", optional = true }
+blitz-traits = { path = "../blitz-traits" }
 
 # IO & Networking
 url = { workspace = true, features = ["serde"], optional = true }

packages/blitz/src/lib.rs

@@ -9,12 +9,15 @@
 //!  - `menu`: Enables the [`muda`] menubar.
 //!  - `tracing`: Enables tracing support.
 
+use std::sync::Arc;
+
 use blitz_html::HtmlDocument;
 use blitz_renderer_vello::BlitzVelloRenderer;
 use blitz_shell::{
     create_default_event_loop, BlitzApplication, BlitzEvent, BlitzShellNetCallback, Config,
     WindowConfig,
 };
+use blitz_traits::navigation::DummyNavigationProvider;
 
 #[cfg(feature = "net")]
 pub fn launch_url(url: &str) {
@@ -74,7 +77,16 @@ fn launch_internal(html: &str, cfg: Config) {
         Arc::new(DummyNetProvider::default())
     };
 
-    let doc = HtmlDocument::from_html(html, cfg.base_url, cfg.stylesheets, net_provider, None);
+    let navigation_provider = Arc::new(DummyNavigationProvider);
+
+    let doc = HtmlDocument::from_html(
+        html,
+        cfg.base_url,
+        cfg.stylesheets,
+        net_provider,
+        None,
+        navigation_provider,
+    );
     let window: WindowConfig<HtmlDocument, BlitzVelloRenderer> = WindowConfig::new(doc);
 
     // Create application