Ely Office: six offline-first desktop apps in Rust and GPUI

ElyDoc, ElyTable, ElyShow (LibreOfficeKit), ElyPDF (MuPDF), ElyTree (Git),
ElyMark (Milkdown and CodeMirror in CEF). ElyMail and ElyAgent follow.

apps/ely-pdf/src/links.rs

@@ -0,0 +1,63 @@
+//! Links: followed, drawn, retargeted, deleted (PDF-07).
+
+use ely_pdf_engine::{Link, Target};
+use gpui::Context;
+
+use crate::view::{Failed, PdfView};
+
+/// Addresses that may leave the document.
+pub fn outward(uri: &str) -> bool {
+    ["https://", "http://", "mailto:"].iter().any(|scheme| uri.starts_with(scheme))
+}
+
+/// A target as typed: a page number or an address.
+pub fn parse(typed: &str, pages: usize) -> Option<Target> {
+    let typed = typed.trim();
+    match typed.parse::<usize>() {
+        Ok(n) => (1..=pages).contains(&n).then(|| Target::Page(n - 1, 0.0)),
+        Err(_) => outward(typed).then(|| Target::Web(typed.to_string())),
+    }
+}
+
+/// A link's target as a person types it.
+pub fn typed(link: &Link) -> String {
+    match link.page {
+        Some(page) => (page + 1).to_string(),
+        None => link.uri.clone(),
+    }
+}
+
+impl PdfView {
+    /// Goes where `link` points; only web and mail leave.
+    pub fn follow(&mut self, link: &Link, cx: &mut Context<Self>) {
+        match link.page {
+            Some(page) => {
+                log::info!("pdf: follows a link to page {}", page + 1);
+                self.show(page, link.y, cx)
+            }
+            None if outward(&link.uri) => {
+                log::info!("pdf: opens a link outside");
+                cx.open_url(&link.uri)
+            }
+            None => {
+                let text = crate::viewer::Viewer::text(cx, "pdf.link.refused", &[]);
+                cx.emit(Failed(text.to_string()))
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn a_target_is_a_page_in_range_or_a_web_or_mail_address() {
+        assert_eq!(parse(" 3 ", 5), Some(Target::Page(2, 0.0)));
+        assert_eq!(parse("9", 5), None);
+        assert_eq!(parse("0", 5), None);
+        assert_eq!(parse("https://a.b", 5), Some(Target::Web("https://a.b".into())));
+        assert_eq!(parse("javascript:x", 5), None);
+        assert_eq!(parse("file:///etc", 5), None);
+    }
+}