Add markdown rendering to alongside completion docs

crates/editor/src/editor.rs

@@ -9,6 +9,7 @@ mod highlight_matching_bracket;
 mod hover_popover;
 pub mod items;
 mod link_go_to_definition;
+mod markdown;
 mod mouse_context_menu;
 pub mod movement;
 pub mod multi_buffer;
@@ -845,11 +846,12 @@ impl ContextMenu {
     fn render(
         &self,
         cursor_position: DisplayPoint,
+        editor: &Editor,
         style: EditorStyle,
         cx: &mut ViewContext<Editor>,
     ) -> (DisplayPoint, AnyElement<Editor>) {
         match self {
-            ContextMenu::Completions(menu) => (cursor_position, menu.render(style, cx)),
+            ContextMenu::Completions(menu) => (cursor_position, menu.render(editor, style, cx)),
             ContextMenu::CodeActions(menu) => menu.render(cursor_position, style, cx),
         }
     }
@@ -899,7 +901,12 @@ impl CompletionsMenu {
         !self.matches.is_empty()
     }
 
-    fn render(&self, style: EditorStyle, cx: &mut ViewContext<Editor>) -> AnyElement<Editor> {
+    fn render(
+        &self,
+        editor: &Editor,
+        style: EditorStyle,
+        cx: &mut ViewContext<Editor>,
+    ) -> AnyElement<Editor> {
         enum CompletionTag {}
 
         let widest_completion_ix = self
@@ -923,18 +930,12 @@ impl CompletionsMenu {
         let matches = self.matches.clone();
         let selected_item = self.selected_item;
 
-        let alongside_docs_text_style = TextStyle {
-            soft_wrap: true,
-            ..style.text.clone()
-        };
         let alongside_docs_width = style.autocomplete.alongside_docs_width;
         let alongside_docs_container_style = style.autocomplete.alongside_docs_container;
         let outer_container_style = style.autocomplete.container;
 
-        let list = UniformList::new(
-            self.list.clone(),
-            matches.len(),
-            cx,
+        let list = UniformList::new(self.list.clone(), matches.len(), cx, {
+            let style = style.clone();
             move |_, range, items, cx| {
                 let start_ix = range.start;
                 for (ix, mat) in matches[range].iter().enumerate() {
@@ -1043,8 +1044,8 @@ impl CompletionsMenu {
                         .into_any(),
                     );
                 }
-            },
-        )
+            }
+        })
         .with_width_from_item(widest_completion_ix);
 
         Flex::row()
@@ -1055,12 +1056,26 @@ impl CompletionsMenu {
                 let documentation = &completion.lsp_completion.documentation;
 
                 if let Some(lsp::Documentation::MarkupContent(content)) = documentation {
+                    let registry = editor
+                        .project
+                        .as_ref()
+                        .unwrap()
+                        .read(cx)
+                        .languages()
+                        .clone();
+                    let language = self.buffer.read(cx).language().map(Arc::clone);
                     Some(
-                        Text::new(content.value.clone(), alongside_docs_text_style)
-                            .constrained()
-                            .with_width(alongside_docs_width)
-                            .contained()
-                            .with_style(alongside_docs_container_style),
+                        crate::markdown::render_markdown(
+                            &content.value,
+                            &registry,
+                            &language,
+                            &style,
+                            cx,
+                        )
+                        .constrained()
+                        .with_width(alongside_docs_width)
+                        .contained()
+                        .with_style(alongside_docs_container_style),
                     )
                 } else {
                     None
@@ -3985,7 +4000,7 @@ impl Editor {
     ) -> Option<(DisplayPoint, AnyElement<Editor>)> {
         self.context_menu
             .as_ref()
-            .map(|menu| menu.render(cursor_position, style, cx))
+            .map(|menu| menu.render(cursor_position, self, style, cx))
     }
 
     fn show_context_menu(&mut self, menu: ContextMenu, cx: &mut ViewContext<Self>) {

crates/editor/src/markdown.rs

@@ -0,0 +1,246 @@
+use std::ops::Range;
+use std::sync::Arc;
+
+use futures::FutureExt;
+use gpui::{
+    elements::Text,
+    fonts::{HighlightStyle, Underline, Weight},
+    platform::{CursorStyle, MouseButton},
+    CursorRegion, MouseRegion, ViewContext,
+};
+use language::{Language, LanguageRegistry};
+use pulldown_cmark::{CodeBlockKind, Event, Options, Parser, Tag};
+
+use crate::{Editor, EditorStyle};
+
+#[derive(Debug, Clone)]
+struct RenderedRegion {
+    code: bool,
+    link_url: Option<String>,
+}
+
+pub fn render_markdown(
+    markdown: &str,
+    language_registry: &Arc<LanguageRegistry>,
+    language: &Option<Arc<Language>>,
+    style: &EditorStyle,
+    cx: &mut ViewContext<Editor>,
+) -> Text {
+    let mut text = String::new();
+    let mut highlights = Vec::new();
+    let mut region_ranges = Vec::new();
+    let mut regions = Vec::new();
+
+    let mut bold_depth = 0;
+    let mut italic_depth = 0;
+    let mut link_url = None;
+    let mut current_language = None;
+    let mut list_stack = Vec::new();
+
+    for event in Parser::new_ext(&markdown, Options::all()) {
+        let prev_len = text.len();
+        match event {
+            Event::Text(t) => {
+                if let Some(language) = &current_language {
+                    render_code(&mut text, &mut highlights, t.as_ref(), language, style);
+                } else {
+                    text.push_str(t.as_ref());
+
+                    let mut style = HighlightStyle::default();
+                    if bold_depth > 0 {
+                        style.weight = Some(Weight::BOLD);
+                    }
+                    if italic_depth > 0 {
+                        style.italic = Some(true);
+                    }
+                    if let Some(link_url) = link_url.clone() {
+                        region_ranges.push(prev_len..text.len());
+                        regions.push(RenderedRegion {
+                            link_url: Some(link_url),
+                            code: false,
+                        });
+                        style.underline = Some(Underline {
+                            thickness: 1.0.into(),
+                            ..Default::default()
+                        });
+                    }
+
+                    if style != HighlightStyle::default() {
+                        let mut new_highlight = true;
+                        if let Some((last_range, last_style)) = highlights.last_mut() {
+                            if last_range.end == prev_len && last_style == &style {
+                                last_range.end = text.len();
+                                new_highlight = false;
+                            }
+                        }
+                        if new_highlight {
+                            highlights.push((prev_len..text.len(), style));
+                        }
+                    }
+                }
+            }
+
+            Event::Code(t) => {
+                text.push_str(t.as_ref());
+                region_ranges.push(prev_len..text.len());
+                if link_url.is_some() {
+                    highlights.push((
+                        prev_len..text.len(),
+                        HighlightStyle {
+                            underline: Some(Underline {
+                                thickness: 1.0.into(),
+                                ..Default::default()
+                            }),
+                            ..Default::default()
+                        },
+                    ));
+                }
+                regions.push(RenderedRegion {
+                    code: true,
+                    link_url: link_url.clone(),
+                });
+            }
+
+            Event::Start(tag) => match tag {
+                Tag::Paragraph => new_paragraph(&mut text, &mut list_stack),
+
+                Tag::Heading(_, _, _) => {
+                    new_paragraph(&mut text, &mut list_stack);
+                    bold_depth += 1;
+                }
+
+                Tag::CodeBlock(kind) => {
+                    new_paragraph(&mut text, &mut list_stack);
+                    current_language = if let CodeBlockKind::Fenced(language) = kind {
+                        language_registry
+                            .language_for_name(language.as_ref())
+                            .now_or_never()
+                            .and_then(Result::ok)
+                    } else {
+                        language.clone()
+                    }
+                }
+
+                Tag::Emphasis => italic_depth += 1,
+
+                Tag::Strong => bold_depth += 1,
+
+                Tag::Link(_, url, _) => link_url = Some(url.to_string()),
+
+                Tag::List(number) => {
+                    list_stack.push((number, false));
+                }
+
+                Tag::Item => {
+                    let len = list_stack.len();
+                    if let Some((list_number, has_content)) = list_stack.last_mut() {
+                        *has_content = false;
+                        if !text.is_empty() && !text.ends_with('\n') {
+                            text.push('\n');
+                        }
+                        for _ in 0..len - 1 {
+                            text.push_str("  ");
+                        }
+                        if let Some(number) = list_number {
+                            text.push_str(&format!("{}. ", number));
+                            *number += 1;
+                            *has_content = false;
+                        } else {
+                            text.push_str("- ");
+                        }
+                    }
+                }
+
+                _ => {}
+            },
+
+            Event::End(tag) => match tag {
+                Tag::Heading(_, _, _) => bold_depth -= 1,
+                Tag::CodeBlock(_) => current_language = None,
+                Tag::Emphasis => italic_depth -= 1,
+                Tag::Strong => bold_depth -= 1,
+                Tag::Link(_, _, _) => link_url = None,
+                Tag::List(_) => drop(list_stack.pop()),
+                _ => {}
+            },
+
+            Event::HardBreak => text.push('\n'),
+
+            Event::SoftBreak => text.push(' '),
+
+            _ => {}
+        }
+    }
+
+    let code_span_background_color = style.document_highlight_read_background;
+    let view_id = cx.view_id();
+    let mut region_id = 0;
+    Text::new(text, style.text.clone())
+        .with_highlights(highlights)
+        .with_custom_runs(region_ranges, move |ix, bounds, scene, _| {
+            region_id += 1;
+            let region = regions[ix].clone();
+            if let Some(url) = region.link_url {
+                scene.push_cursor_region(CursorRegion {
+                    bounds,
+                    style: CursorStyle::PointingHand,
+                });
+                scene.push_mouse_region(
+                    MouseRegion::new::<Editor>(view_id, region_id, bounds)
+                        .on_click::<Editor, _>(MouseButton::Left, move |_, _, cx| {
+                            cx.platform().open_url(&url)
+                        }),
+                );
+            }
+            if region.code {
+                scene.push_quad(gpui::Quad {
+                    bounds,
+                    background: Some(code_span_background_color),
+                    border: Default::default(),
+                    corner_radii: (2.0).into(),
+                });
+            }
+        })
+        .with_soft_wrap(true)
+}
+
+fn render_code(
+    text: &mut String,
+    highlights: &mut Vec<(Range<usize>, HighlightStyle)>,
+    content: &str,
+    language: &Arc<Language>,
+    style: &EditorStyle,
+) {
+    let prev_len = text.len();
+    text.push_str(content);
+    for (range, highlight_id) in language.highlight_text(&content.into(), 0..content.len()) {
+        if let Some(style) = highlight_id.style(&style.syntax) {
+            highlights.push((prev_len + range.start..prev_len + range.end, style));
+        }
+    }
+}
+
+fn new_paragraph(text: &mut String, list_stack: &mut Vec<(Option<u64>, bool)>) {
+    let mut is_subsequent_paragraph_of_list = false;
+    if let Some((_, has_content)) = list_stack.last_mut() {
+        if *has_content {
+            is_subsequent_paragraph_of_list = true;
+        } else {
+            *has_content = true;
+            return;
+        }
+    }
+
+    if !text.is_empty() {
+        if !text.ends_with('\n') {
+            text.push('\n');
+        }
+        text.push('\n');
+    }
+    for _ in 0..list_stack.len().saturating_sub(1) {
+        text.push_str("  ");
+    }
+    if is_subsequent_paragraph_of_list {
+        text.push_str("  ");
+    }
+}

styles/src/style_tree/editor.ts

@@ -209,7 +209,7 @@ export default function editor(): any {
             inline_docs_container: { padding: { left: 40 } },
             inline_docs_color: text(theme.middle, "sans", "disabled", {}).color,
             inline_docs_size_percent: 0.75,
-            alongside_docs_width: 400,
+            alongside_docs_width: 700,
             alongside_docs_container: { padding: autocomplete_item.padding }
         },
         diagnostic_header: {