markdown.rs

   1pub mod parser;
   2mod path_range;
   3
   4use base64::Engine as _;
   5use futures::FutureExt as _;
   6use gpui::HitboxBehavior;
   7use language::LanguageName;
   8use log::Level;
   9pub use path_range::{LineCol, PathWithRange};
  10use ui::Checkbox;
  11
  12use std::borrow::Cow;
  13use std::iter;
  14use std::mem;
  15use std::ops::Range;
  16use std::path::Path;
  17use std::rc::Rc;
  18use std::sync::Arc;
  19use std::time::Duration;
  20
  21use collections::{HashMap, HashSet};
  22use gpui::{
  23    AnyElement, App, BorderStyle, Bounds, ClipboardItem, CursorStyle, DispatchPhase, Edges, Entity,
  24    FocusHandle, Focusable, FontStyle, FontWeight, GlobalElementId, Hitbox, Hsla, Image,
  25    ImageFormat, KeyContext, Length, MouseDownEvent, MouseEvent, MouseMoveEvent, MouseUpEvent,
  26    Point, ScrollHandle, Stateful, StrikethroughStyle, StyleRefinement, StyledText, Task,
  27    TextLayout, TextRun, TextStyle, TextStyleRefinement, actions, img, point, quad,
  28};
  29use language::{Language, LanguageRegistry, Rope};
  30use parser::CodeBlockMetadata;
  31use parser::{MarkdownEvent, MarkdownTag, MarkdownTagEnd, parse_links_only, parse_markdown};
  32use pulldown_cmark::Alignment;
  33use sum_tree::TreeMap;
  34use theme::SyntaxTheme;
  35use ui::{ScrollAxes, Scrollbars, Tooltip, WithScrollbar, prelude::*};
  36use util::ResultExt;
  37
  38use crate::parser::CodeBlockKind;
  39
  40/// A callback function that can be used to customize the style of links based on the destination URL.
  41/// If the callback returns `None`, the default link style will be used.
  42type LinkStyleCallback = Rc<dyn Fn(&str, &App) -> Option<TextStyleRefinement>>;
  43
  44/// Defines custom style refinements for each heading level (H1-H6)
  45#[derive(Clone, Default)]
  46pub struct HeadingLevelStyles {
  47    pub h1: Option<TextStyleRefinement>,
  48    pub h2: Option<TextStyleRefinement>,
  49    pub h3: Option<TextStyleRefinement>,
  50    pub h4: Option<TextStyleRefinement>,
  51    pub h5: Option<TextStyleRefinement>,
  52    pub h6: Option<TextStyleRefinement>,
  53}
  54
  55#[derive(Clone)]
  56pub struct MarkdownStyle {
  57    pub base_text_style: TextStyle,
  58    pub container_style: StyleRefinement,
  59    pub code_block: StyleRefinement,
  60    pub code_block_overflow_x_scroll: bool,
  61    pub inline_code: TextStyleRefinement,
  62    pub block_quote: TextStyleRefinement,
  63    pub link: TextStyleRefinement,
  64    pub link_callback: Option<LinkStyleCallback>,
  65    pub rule_color: Hsla,
  66    pub block_quote_border_color: Hsla,
  67    pub syntax: Arc<SyntaxTheme>,
  68    pub selection_background_color: Hsla,
  69    pub heading: StyleRefinement,
  70    pub heading_level_styles: Option<HeadingLevelStyles>,
  71    pub height_is_multiple_of_line_height: bool,
  72    pub prevent_mouse_interaction: bool,
  73    pub table_columns_min_size: bool,
  74}
  75
  76impl Default for MarkdownStyle {
  77    fn default() -> Self {
  78        Self {
  79            base_text_style: Default::default(),
  80            container_style: Default::default(),
  81            code_block: Default::default(),
  82            code_block_overflow_x_scroll: false,
  83            inline_code: Default::default(),
  84            block_quote: Default::default(),
  85            link: Default::default(),
  86            link_callback: None,
  87            rule_color: Default::default(),
  88            block_quote_border_color: Default::default(),
  89            syntax: Arc::new(SyntaxTheme::default()),
  90            selection_background_color: Default::default(),
  91            heading: Default::default(),
  92            heading_level_styles: None,
  93            height_is_multiple_of_line_height: false,
  94            prevent_mouse_interaction: false,
  95            table_columns_min_size: false,
  96        }
  97    }
  98}
  99
 100pub struct Markdown {
 101    source: SharedString,
 102    selection: Selection,
 103    pressed_link: Option<RenderedLink>,
 104    autoscroll_request: Option<usize>,
 105    parsed_markdown: ParsedMarkdown,
 106    images_by_source_offset: HashMap<usize, Arc<Image>>,
 107    should_reparse: bool,
 108    pending_parse: Option<Task<()>>,
 109    focus_handle: FocusHandle,
 110    language_registry: Option<Arc<LanguageRegistry>>,
 111    fallback_code_block_language: Option<LanguageName>,
 112    options: Options,
 113    copied_code_blocks: HashSet<ElementId>,
 114    code_block_scroll_handles: HashMap<usize, ScrollHandle>,
 115}
 116
 117struct Options {
 118    parse_links_only: bool,
 119}
 120
 121pub enum CodeBlockRenderer {
 122    Default {
 123        copy_button: bool,
 124        copy_button_on_hover: bool,
 125        border: bool,
 126    },
 127    Custom {
 128        render: CodeBlockRenderFn,
 129        /// A function that can modify the parent container after the code block
 130        /// content has been appended as a child element.
 131        transform: Option<CodeBlockTransformFn>,
 132    },
 133}
 134
 135pub type CodeBlockRenderFn = Arc<
 136    dyn Fn(
 137        &CodeBlockKind,
 138        &ParsedMarkdown,
 139        Range<usize>,
 140        CodeBlockMetadata,
 141        &mut Window,
 142        &App,
 143    ) -> Div,
 144>;
 145
 146pub type CodeBlockTransformFn =
 147    Arc<dyn Fn(AnyDiv, Range<usize>, CodeBlockMetadata, &mut Window, &App) -> AnyDiv>;
 148
 149actions!(
 150    markdown,
 151    [
 152        /// Copies the selected text to the clipboard.
 153        Copy,
 154    ]
 155);
 156
 157impl Markdown {
 158    pub fn new(
 159        source: SharedString,
 160        language_registry: Option<Arc<LanguageRegistry>>,
 161        fallback_code_block_language: Option<LanguageName>,
 162        cx: &mut Context<Self>,
 163    ) -> Self {
 164        let focus_handle = cx.focus_handle();
 165        let mut this = Self {
 166            source,
 167            selection: Selection::default(),
 168            pressed_link: None,
 169            autoscroll_request: None,
 170            should_reparse: false,
 171            images_by_source_offset: Default::default(),
 172            parsed_markdown: ParsedMarkdown::default(),
 173            pending_parse: None,
 174            focus_handle,
 175            language_registry,
 176            fallback_code_block_language,
 177            options: Options {
 178                parse_links_only: false,
 179            },
 180            copied_code_blocks: HashSet::default(),
 181            code_block_scroll_handles: HashMap::default(),
 182        };
 183        this.parse(cx);
 184        this
 185    }
 186
 187    pub fn new_text(source: SharedString, cx: &mut Context<Self>) -> Self {
 188        let focus_handle = cx.focus_handle();
 189        let mut this = Self {
 190            source,
 191            selection: Selection::default(),
 192            pressed_link: None,
 193            autoscroll_request: None,
 194            should_reparse: false,
 195            parsed_markdown: ParsedMarkdown::default(),
 196            images_by_source_offset: Default::default(),
 197            pending_parse: None,
 198            focus_handle,
 199            language_registry: None,
 200            fallback_code_block_language: None,
 201            options: Options {
 202                parse_links_only: true,
 203            },
 204            copied_code_blocks: HashSet::default(),
 205            code_block_scroll_handles: HashMap::default(),
 206        };
 207        this.parse(cx);
 208        this
 209    }
 210
 211    fn code_block_scroll_handle(&mut self, id: usize) -> ScrollHandle {
 212        self.code_block_scroll_handles
 213            .entry(id)
 214            .or_insert_with(ScrollHandle::new)
 215            .clone()
 216    }
 217
 218    fn retain_code_block_scroll_handles(&mut self, ids: &HashSet<usize>) {
 219        self.code_block_scroll_handles
 220            .retain(|id, _| ids.contains(id));
 221    }
 222
 223    fn clear_code_block_scroll_handles(&mut self) {
 224        self.code_block_scroll_handles.clear();
 225    }
 226
 227    pub fn is_parsing(&self) -> bool {
 228        self.pending_parse.is_some()
 229    }
 230
 231    pub fn source(&self) -> &str {
 232        &self.source
 233    }
 234
 235    pub fn append(&mut self, text: &str, cx: &mut Context<Self>) {
 236        self.source = SharedString::new(self.source.to_string() + text);
 237        self.parse(cx);
 238    }
 239
 240    pub fn replace(&mut self, source: impl Into<SharedString>, cx: &mut Context<Self>) {
 241        self.source = source.into();
 242        self.parse(cx);
 243    }
 244
 245    pub fn reset(&mut self, source: SharedString, cx: &mut Context<Self>) {
 246        if source == self.source() {
 247            return;
 248        }
 249        self.source = source;
 250        self.selection = Selection::default();
 251        self.autoscroll_request = None;
 252        self.pending_parse = None;
 253        self.should_reparse = false;
 254        // Don't clear parsed_markdown here - keep existing content visible until new parse completes
 255        self.parse(cx);
 256    }
 257
 258    #[cfg(any(test, feature = "test-support"))]
 259    pub fn parsed_markdown(&self) -> &ParsedMarkdown {
 260        &self.parsed_markdown
 261    }
 262
 263    pub fn escape(s: &str) -> Cow<'_, str> {
 264        // Valid to use bytes since multi-byte UTF-8 doesn't use ASCII chars.
 265        let count = s
 266            .bytes()
 267            .filter(|c| *c == b'\n' || c.is_ascii_punctuation())
 268            .count();
 269        if count > 0 {
 270            let mut output = String::with_capacity(s.len() + count);
 271            let mut is_newline = false;
 272            for c in s.chars() {
 273                if is_newline && c == ' ' {
 274                    continue;
 275                }
 276                is_newline = c == '\n';
 277                if c == '\n' {
 278                    output.push('\n')
 279                } else if c.is_ascii_punctuation() {
 280                    output.push('\\')
 281                }
 282                output.push(c)
 283            }
 284            output.into()
 285        } else {
 286            s.into()
 287        }
 288    }
 289
 290    fn copy(&self, text: &RenderedText, _: &mut Window, cx: &mut Context<Self>) {
 291        if self.selection.end <= self.selection.start {
 292            return;
 293        }
 294        let text = text.text_for_range(self.selection.start..self.selection.end);
 295        cx.write_to_clipboard(ClipboardItem::new_string(text));
 296    }
 297
 298    fn parse(&mut self, cx: &mut Context<Self>) {
 299        if self.source.is_empty() {
 300            return;
 301        }
 302
 303        if self.pending_parse.is_some() {
 304            self.should_reparse = true;
 305            return;
 306        }
 307        self.should_reparse = false;
 308        self.pending_parse = Some(self.start_background_parse(cx));
 309    }
 310
 311    fn start_background_parse(&self, cx: &Context<Self>) -> Task<()> {
 312        let source = self.source.clone();
 313        let should_parse_links_only = self.options.parse_links_only;
 314        let language_registry = self.language_registry.clone();
 315        let fallback = self.fallback_code_block_language.clone();
 316
 317        let parsed = cx.background_spawn(async move {
 318            if should_parse_links_only {
 319                return (
 320                    ParsedMarkdown {
 321                        events: Arc::from(parse_links_only(source.as_ref())),
 322                        source,
 323                        languages_by_name: TreeMap::default(),
 324                        languages_by_path: TreeMap::default(),
 325                    },
 326                    Default::default(),
 327                );
 328            }
 329
 330            let (events, language_names, paths) = parse_markdown(&source);
 331            let mut images_by_source_offset = HashMap::default();
 332            let mut languages_by_name = TreeMap::default();
 333            let mut languages_by_path = TreeMap::default();
 334            if let Some(registry) = language_registry.as_ref() {
 335                for name in language_names {
 336                    let language = if !name.is_empty() {
 337                        registry.language_for_name_or_extension(&name).left_future()
 338                    } else if let Some(fallback) = &fallback {
 339                        registry.language_for_name(fallback.as_ref()).right_future()
 340                    } else {
 341                        continue;
 342                    };
 343                    if let Ok(language) = language.await {
 344                        languages_by_name.insert(name, language);
 345                    }
 346                }
 347
 348                for path in paths {
 349                    if let Ok(language) = registry
 350                        .load_language_for_file_path(Path::new(path.as_ref()))
 351                        .await
 352                    {
 353                        languages_by_path.insert(path, language);
 354                    }
 355                }
 356            }
 357
 358            for (range, event) in &events {
 359                if let MarkdownEvent::Start(MarkdownTag::Image { dest_url, .. }) = event
 360                    && let Some(data_url) = dest_url.strip_prefix("data:")
 361                {
 362                    let Some((mime_info, data)) = data_url.split_once(',') else {
 363                        continue;
 364                    };
 365                    let Some((mime_type, encoding)) = mime_info.split_once(';') else {
 366                        continue;
 367                    };
 368                    let Some(format) = ImageFormat::from_mime_type(mime_type) else {
 369                        continue;
 370                    };
 371                    let is_base64 = encoding == "base64";
 372                    if is_base64
 373                        && let Some(bytes) = base64::prelude::BASE64_STANDARD
 374                            .decode(data)
 375                            .log_with_level(Level::Debug)
 376                    {
 377                        let image = Arc::new(Image::from_bytes(format, bytes));
 378                        images_by_source_offset.insert(range.start, image);
 379                    }
 380                }
 381            }
 382
 383            (
 384                ParsedMarkdown {
 385                    source,
 386                    events: Arc::from(events),
 387                    languages_by_name,
 388                    languages_by_path,
 389                },
 390                images_by_source_offset,
 391            )
 392        });
 393
 394        cx.spawn(async move |this, cx| {
 395            let (parsed, images_by_source_offset) = parsed.await;
 396
 397            this.update(cx, |this, cx| {
 398                this.parsed_markdown = parsed;
 399                this.images_by_source_offset = images_by_source_offset;
 400                this.pending_parse.take();
 401                if this.should_reparse {
 402                    this.parse(cx);
 403                }
 404                cx.refresh_windows();
 405            })
 406            .ok();
 407        })
 408    }
 409}
 410
 411impl Focusable for Markdown {
 412    fn focus_handle(&self, _cx: &App) -> FocusHandle {
 413        self.focus_handle.clone()
 414    }
 415}
 416
 417#[derive(Debug, Default, Clone)]
 418enum SelectMode {
 419    #[default]
 420    Character,
 421    Word(Range<usize>),
 422    Line(Range<usize>),
 423    All,
 424}
 425
 426#[derive(Clone, Default)]
 427struct Selection {
 428    start: usize,
 429    end: usize,
 430    reversed: bool,
 431    pending: bool,
 432    mode: SelectMode,
 433}
 434
 435impl Selection {
 436    fn set_head(&mut self, head: usize, rendered_text: &RenderedText) {
 437        match &self.mode {
 438            SelectMode::Character => {
 439                if head < self.tail() {
 440                    if !self.reversed {
 441                        self.end = self.start;
 442                        self.reversed = true;
 443                    }
 444                    self.start = head;
 445                } else {
 446                    if self.reversed {
 447                        self.start = self.end;
 448                        self.reversed = false;
 449                    }
 450                    self.end = head;
 451                }
 452            }
 453            SelectMode::Word(original_range) | SelectMode::Line(original_range) => {
 454                let head_range = if matches!(self.mode, SelectMode::Word(_)) {
 455                    rendered_text.surrounding_word_range(head)
 456                } else {
 457                    rendered_text.surrounding_line_range(head)
 458                };
 459
 460                if head < original_range.start {
 461                    self.start = head_range.start;
 462                    self.end = original_range.end;
 463                    self.reversed = true;
 464                } else if head >= original_range.end {
 465                    self.start = original_range.start;
 466                    self.end = head_range.end;
 467                    self.reversed = false;
 468                } else {
 469                    self.start = original_range.start;
 470                    self.end = original_range.end;
 471                    self.reversed = false;
 472                }
 473            }
 474            SelectMode::All => {
 475                self.start = 0;
 476                self.end = rendered_text
 477                    .lines
 478                    .last()
 479                    .map(|line| line.source_end)
 480                    .unwrap_or(0);
 481                self.reversed = false;
 482            }
 483        }
 484    }
 485
 486    fn tail(&self) -> usize {
 487        if self.reversed { self.end } else { self.start }
 488    }
 489}
 490
 491#[derive(Debug, Clone, Default)]
 492pub struct ParsedMarkdown {
 493    pub source: SharedString,
 494    pub events: Arc<[(Range<usize>, MarkdownEvent)]>,
 495    pub languages_by_name: TreeMap<SharedString, Arc<Language>>,
 496    pub languages_by_path: TreeMap<Arc<str>, Arc<Language>>,
 497}
 498
 499impl ParsedMarkdown {
 500    pub fn source(&self) -> &SharedString {
 501        &self.source
 502    }
 503
 504    pub fn events(&self) -> &Arc<[(Range<usize>, MarkdownEvent)]> {
 505        &self.events
 506    }
 507}
 508
 509pub struct MarkdownElement {
 510    markdown: Entity<Markdown>,
 511    style: MarkdownStyle,
 512    code_block_renderer: CodeBlockRenderer,
 513    on_url_click: Option<Box<dyn Fn(SharedString, &mut Window, &mut App)>>,
 514}
 515
 516impl MarkdownElement {
 517    pub fn new(markdown: Entity<Markdown>, style: MarkdownStyle) -> Self {
 518        Self {
 519            markdown,
 520            style,
 521            code_block_renderer: CodeBlockRenderer::Default {
 522                copy_button: true,
 523                copy_button_on_hover: false,
 524                border: false,
 525            },
 526            on_url_click: None,
 527        }
 528    }
 529
 530    #[cfg(any(test, feature = "test-support"))]
 531    pub fn rendered_text(
 532        markdown: Entity<Markdown>,
 533        cx: &mut gpui::VisualTestContext,
 534        style: impl FnOnce(&Window, &App) -> MarkdownStyle,
 535    ) -> String {
 536        use gpui::size;
 537
 538        let (text, _) = cx.draw(
 539            Default::default(),
 540            size(px(600.0), px(600.0)),
 541            |window, cx| Self::new(markdown, style(window, cx)),
 542        );
 543        text.text
 544            .lines
 545            .iter()
 546            .map(|line| line.layout.wrapped_text())
 547            .collect::<Vec<_>>()
 548            .join("\n")
 549    }
 550
 551    pub fn code_block_renderer(mut self, variant: CodeBlockRenderer) -> Self {
 552        self.code_block_renderer = variant;
 553        self
 554    }
 555
 556    pub fn on_url_click(
 557        mut self,
 558        handler: impl Fn(SharedString, &mut Window, &mut App) + 'static,
 559    ) -> Self {
 560        self.on_url_click = Some(Box::new(handler));
 561        self
 562    }
 563
 564    fn paint_selection(
 565        &self,
 566        bounds: Bounds<Pixels>,
 567        rendered_text: &RenderedText,
 568        window: &mut Window,
 569        cx: &mut App,
 570    ) {
 571        let selection = self.markdown.read(cx).selection.clone();
 572        let selection_start = rendered_text.position_for_source_index(selection.start);
 573        let selection_end = rendered_text.position_for_source_index(selection.end);
 574        if let Some(((start_position, start_line_height), (end_position, end_line_height))) =
 575            selection_start.zip(selection_end)
 576        {
 577            if start_position.y == end_position.y {
 578                window.paint_quad(quad(
 579                    Bounds::from_corners(
 580                        start_position,
 581                        point(end_position.x, end_position.y + end_line_height),
 582                    ),
 583                    Pixels::ZERO,
 584                    self.style.selection_background_color,
 585                    Edges::default(),
 586                    Hsla::transparent_black(),
 587                    BorderStyle::default(),
 588                ));
 589            } else {
 590                window.paint_quad(quad(
 591                    Bounds::from_corners(
 592                        start_position,
 593                        point(bounds.right(), start_position.y + start_line_height),
 594                    ),
 595                    Pixels::ZERO,
 596                    self.style.selection_background_color,
 597                    Edges::default(),
 598                    Hsla::transparent_black(),
 599                    BorderStyle::default(),
 600                ));
 601
 602                if end_position.y > start_position.y + start_line_height {
 603                    window.paint_quad(quad(
 604                        Bounds::from_corners(
 605                            point(bounds.left(), start_position.y + start_line_height),
 606                            point(bounds.right(), end_position.y),
 607                        ),
 608                        Pixels::ZERO,
 609                        self.style.selection_background_color,
 610                        Edges::default(),
 611                        Hsla::transparent_black(),
 612                        BorderStyle::default(),
 613                    ));
 614                }
 615
 616                window.paint_quad(quad(
 617                    Bounds::from_corners(
 618                        point(bounds.left(), end_position.y),
 619                        point(end_position.x, end_position.y + end_line_height),
 620                    ),
 621                    Pixels::ZERO,
 622                    self.style.selection_background_color,
 623                    Edges::default(),
 624                    Hsla::transparent_black(),
 625                    BorderStyle::default(),
 626                ));
 627            }
 628        }
 629    }
 630
 631    fn paint_mouse_listeners(
 632        &mut self,
 633        hitbox: &Hitbox,
 634        rendered_text: &RenderedText,
 635        window: &mut Window,
 636        cx: &mut App,
 637    ) {
 638        if self.style.prevent_mouse_interaction {
 639            return;
 640        }
 641
 642        let is_hovering_link = hitbox.is_hovered(window)
 643            && !self.markdown.read(cx).selection.pending
 644            && rendered_text
 645                .link_for_position(window.mouse_position())
 646                .is_some();
 647
 648        if !self.style.prevent_mouse_interaction {
 649            if is_hovering_link {
 650                window.set_cursor_style(CursorStyle::PointingHand, hitbox);
 651            } else {
 652                window.set_cursor_style(CursorStyle::IBeam, hitbox);
 653            }
 654        }
 655
 656        let on_open_url = self.on_url_click.take();
 657
 658        self.on_mouse_event(window, cx, {
 659            let rendered_text = rendered_text.clone();
 660            let hitbox = hitbox.clone();
 661            move |markdown, event: &MouseDownEvent, phase, window, cx| {
 662                if hitbox.is_hovered(window) {
 663                    if phase.bubble() {
 664                        if let Some(link) = rendered_text.link_for_position(event.position) {
 665                            markdown.pressed_link = Some(link.clone());
 666                        } else {
 667                            let source_index =
 668                                match rendered_text.source_index_for_position(event.position) {
 669                                    Ok(ix) | Err(ix) => ix,
 670                                };
 671                            let (range, mode) = match event.click_count {
 672                                1 => {
 673                                    let range = source_index..source_index;
 674                                    (range, SelectMode::Character)
 675                                }
 676                                2 => {
 677                                    let range = rendered_text.surrounding_word_range(source_index);
 678                                    (range.clone(), SelectMode::Word(range))
 679                                }
 680                                3 => {
 681                                    let range = rendered_text.surrounding_line_range(source_index);
 682                                    (range.clone(), SelectMode::Line(range))
 683                                }
 684                                _ => {
 685                                    let range = 0..rendered_text
 686                                        .lines
 687                                        .last()
 688                                        .map(|line| line.source_end)
 689                                        .unwrap_or(0);
 690                                    (range, SelectMode::All)
 691                                }
 692                            };
 693                            markdown.selection = Selection {
 694                                start: range.start,
 695                                end: range.end,
 696                                reversed: false,
 697                                pending: true,
 698                                mode,
 699                            };
 700                            window.focus(&markdown.focus_handle);
 701                        }
 702
 703                        window.prevent_default();
 704                        cx.notify();
 705                    }
 706                } else if phase.capture() {
 707                    markdown.selection = Selection::default();
 708                    markdown.pressed_link = None;
 709                    cx.notify();
 710                }
 711            }
 712        });
 713        self.on_mouse_event(window, cx, {
 714            let rendered_text = rendered_text.clone();
 715            let hitbox = hitbox.clone();
 716            let was_hovering_link = is_hovering_link;
 717            move |markdown, event: &MouseMoveEvent, phase, window, cx| {
 718                if phase.capture() {
 719                    return;
 720                }
 721
 722                if markdown.selection.pending {
 723                    let source_index = match rendered_text.source_index_for_position(event.position)
 724                    {
 725                        Ok(ix) | Err(ix) => ix,
 726                    };
 727                    markdown.selection.set_head(source_index, &rendered_text);
 728                    markdown.autoscroll_request = Some(source_index);
 729                    cx.notify();
 730                } else {
 731                    let is_hovering_link = hitbox.is_hovered(window)
 732                        && rendered_text.link_for_position(event.position).is_some();
 733                    if is_hovering_link != was_hovering_link {
 734                        cx.notify();
 735                    }
 736                }
 737            }
 738        });
 739        self.on_mouse_event(window, cx, {
 740            let rendered_text = rendered_text.clone();
 741            move |markdown, event: &MouseUpEvent, phase, window, cx| {
 742                if phase.bubble() {
 743                    if let Some(pressed_link) = markdown.pressed_link.take()
 744                        && Some(&pressed_link) == rendered_text.link_for_position(event.position)
 745                    {
 746                        if let Some(open_url) = on_open_url.as_ref() {
 747                            open_url(pressed_link.destination_url, window, cx);
 748                        } else {
 749                            cx.open_url(&pressed_link.destination_url);
 750                        }
 751                    }
 752                } else if markdown.selection.pending {
 753                    markdown.selection.pending = false;
 754                    #[cfg(any(target_os = "linux", target_os = "freebsd"))]
 755                    {
 756                        let text = rendered_text
 757                            .text_for_range(markdown.selection.start..markdown.selection.end);
 758                        cx.write_to_primary(ClipboardItem::new_string(text))
 759                    }
 760                    cx.notify();
 761                }
 762            }
 763        });
 764    }
 765
 766    fn autoscroll(
 767        &self,
 768        rendered_text: &RenderedText,
 769        window: &mut Window,
 770        cx: &mut App,
 771    ) -> Option<()> {
 772        let autoscroll_index = self
 773            .markdown
 774            .update(cx, |markdown, _| markdown.autoscroll_request.take())?;
 775        let (position, line_height) = rendered_text.position_for_source_index(autoscroll_index)?;
 776
 777        let text_style = self.style.base_text_style.clone();
 778        let font_id = window.text_system().resolve_font(&text_style.font());
 779        let font_size = text_style.font_size.to_pixels(window.rem_size());
 780        let em_width = window.text_system().em_width(font_id, font_size).unwrap();
 781        window.request_autoscroll(Bounds::from_corners(
 782            point(position.x - 3. * em_width, position.y - 3. * line_height),
 783            point(position.x + 3. * em_width, position.y + 3. * line_height),
 784        ));
 785        Some(())
 786    }
 787
 788    fn on_mouse_event<T: MouseEvent>(
 789        &self,
 790        window: &mut Window,
 791        _cx: &mut App,
 792        mut f: impl 'static
 793        + FnMut(&mut Markdown, &T, DispatchPhase, &mut Window, &mut Context<Markdown>),
 794    ) {
 795        window.on_mouse_event({
 796            let markdown = self.markdown.downgrade();
 797            move |event, phase, window, cx| {
 798                markdown
 799                    .update(cx, |markdown, cx| f(markdown, event, phase, window, cx))
 800                    .log_err();
 801            }
 802        });
 803    }
 804}
 805
 806impl Styled for MarkdownElement {
 807    fn style(&mut self) -> &mut StyleRefinement {
 808        &mut self.style.container_style
 809    }
 810}
 811
 812impl Element for MarkdownElement {
 813    type RequestLayoutState = RenderedMarkdown;
 814    type PrepaintState = Hitbox;
 815
 816    fn id(&self) -> Option<ElementId> {
 817        None
 818    }
 819
 820    fn source_location(&self) -> Option<&'static core::panic::Location<'static>> {
 821        None
 822    }
 823
 824    fn request_layout(
 825        &mut self,
 826        _id: Option<&GlobalElementId>,
 827        _inspector_id: Option<&gpui::InspectorElementId>,
 828        window: &mut Window,
 829        cx: &mut App,
 830    ) -> (gpui::LayoutId, Self::RequestLayoutState) {
 831        let mut builder = MarkdownElementBuilder::new(
 832            &self.style.container_style,
 833            self.style.base_text_style.clone(),
 834            self.style.syntax.clone(),
 835        );
 836        let (parsed_markdown, images) = {
 837            let markdown = self.markdown.read(cx);
 838            (
 839                markdown.parsed_markdown.clone(),
 840                markdown.images_by_source_offset.clone(),
 841            )
 842        };
 843        let markdown_end = if let Some(last) = parsed_markdown.events.last() {
 844            last.0.end
 845        } else {
 846            0
 847        };
 848        let mut code_block_ids = HashSet::default();
 849
 850        let mut current_img_block_range: Option<Range<usize>> = None;
 851        for (index, (range, event)) in parsed_markdown.events.iter().enumerate() {
 852            // Skip alt text for images that rendered
 853            if let Some(current_img_block_range) = &current_img_block_range
 854                && current_img_block_range.end > range.end
 855            {
 856                continue;
 857            }
 858
 859            match event {
 860                MarkdownEvent::Start(tag) => {
 861                    match tag {
 862                        MarkdownTag::Image { .. } => {
 863                            if let Some(image) = images.get(&range.start) {
 864                                current_img_block_range = Some(range.clone());
 865                                builder.modify_current_div(|el| {
 866                                    el.items_center()
 867                                        .flex()
 868                                        .flex_row()
 869                                        .child(img(image.clone()))
 870                                });
 871                            }
 872                        }
 873                        MarkdownTag::Paragraph => {
 874                            builder.push_div(
 875                                div().when(!self.style.height_is_multiple_of_line_height, |el| {
 876                                    el.mb_2().line_height(rems(1.3))
 877                                }),
 878                                range,
 879                                markdown_end,
 880                            );
 881                        }
 882                        MarkdownTag::Heading { level, .. } => {
 883                            let mut heading = div().mb_2();
 884
 885                            heading = apply_heading_style(
 886                                heading,
 887                                *level,
 888                                self.style.heading_level_styles.as_ref(),
 889                            );
 890
 891                            heading.style().refine(&self.style.heading);
 892
 893                            let text_style = self.style.heading.text_style().clone();
 894
 895                            builder.push_text_style(text_style);
 896                            builder.push_div(heading, range, markdown_end);
 897                        }
 898                        MarkdownTag::BlockQuote => {
 899                            builder.push_text_style(self.style.block_quote.clone());
 900                            builder.push_div(
 901                                div()
 902                                    .pl_4()
 903                                    .mb_2()
 904                                    .border_l_4()
 905                                    .border_color(self.style.block_quote_border_color),
 906                                range,
 907                                markdown_end,
 908                            );
 909                        }
 910                        MarkdownTag::CodeBlock { kind, .. } => {
 911                            let language = match kind {
 912                                CodeBlockKind::Fenced => None,
 913                                CodeBlockKind::FencedLang(language) => {
 914                                    parsed_markdown.languages_by_name.get(language).cloned()
 915                                }
 916                                CodeBlockKind::FencedSrc(path_range) => parsed_markdown
 917                                    .languages_by_path
 918                                    .get(&path_range.path)
 919                                    .cloned(),
 920                                _ => None,
 921                            };
 922
 923                            let is_indented = matches!(kind, CodeBlockKind::Indented);
 924                            let scroll_handle = if self.style.code_block_overflow_x_scroll {
 925                                code_block_ids.insert(range.start);
 926                                Some(self.markdown.update(cx, |markdown, _| {
 927                                    markdown.code_block_scroll_handle(range.start)
 928                                }))
 929                            } else {
 930                                None
 931                            };
 932
 933                            match (&self.code_block_renderer, is_indented) {
 934                                (CodeBlockRenderer::Default { .. }, _) | (_, true) => {
 935                                    // This is a parent container that we can position the copy button inside.
 936                                    let parent_container =
 937                                        div().group("code_block").relative().w_full();
 938
 939                                    let mut parent_container: AnyDiv = if let Some(scroll_handle) =
 940                                        scroll_handle.as_ref()
 941                                    {
 942                                        let scrollbars = Scrollbars::new(ScrollAxes::Horizontal)
 943                                            .id(("markdown-code-block-scrollbar", range.start))
 944                                            .tracked_scroll_handle(scroll_handle)
 945                                            .with_track_along(
 946                                                ScrollAxes::Horizontal,
 947                                                cx.theme().colors().editor_background,
 948                                            )
 949                                            .notify_content();
 950
 951                                        parent_container
 952                                            .rounded_lg()
 953                                            .custom_scrollbars(scrollbars, window, cx)
 954                                            .into()
 955                                    } else {
 956                                        parent_container.into()
 957                                    };
 958
 959                                    if let CodeBlockRenderer::Default { border: true, .. } =
 960                                        &self.code_block_renderer
 961                                    {
 962                                        parent_container = parent_container
 963                                            .rounded_md()
 964                                            .border_1()
 965                                            .border_color(cx.theme().colors().border_variant);
 966                                    }
 967
 968                                    parent_container.style().refine(&self.style.code_block);
 969                                    builder.push_div(parent_container, range, markdown_end);
 970
 971                                    let code_block = div()
 972                                        .id(("code-block", range.start))
 973                                        .rounded_lg()
 974                                        .map(|mut code_block| {
 975                                            if let Some(scroll_handle) = scroll_handle.as_ref() {
 976                                                code_block.style().restrict_scroll_to_axis =
 977                                                    Some(true);
 978                                                code_block
 979                                                    .flex()
 980                                                    .overflow_x_scroll()
 981                                                    .track_scroll(scroll_handle)
 982                                            } else {
 983                                                code_block.w_full()
 984                                            }
 985                                        });
 986
 987                                    builder.push_text_style(self.style.code_block.text.to_owned());
 988                                    builder.push_code_block(language);
 989                                    builder.push_div(code_block, range, markdown_end);
 990                                }
 991                                (CodeBlockRenderer::Custom { .. }, _) => {}
 992                            }
 993                        }
 994                        MarkdownTag::HtmlBlock => builder.push_div(div(), range, markdown_end),
 995                        MarkdownTag::List(bullet_index) => {
 996                            builder.push_list(*bullet_index);
 997                            builder.push_div(div().pl_2p5(), range, markdown_end);
 998                        }
 999                        MarkdownTag::Item => {
1000                            let bullet = if let Some((_, MarkdownEvent::TaskListMarker(checked))) =
1001                                parsed_markdown.events.get(index.saturating_add(1))
1002                            {
1003                                let source = &parsed_markdown.source()[range.clone()];
1004
1005                                Checkbox::new(
1006                                    ElementId::Name(source.to_string().into()),
1007                                    if *checked {
1008                                        ToggleState::Selected
1009                                    } else {
1010                                        ToggleState::Unselected
1011                                    },
1012                                )
1013                                .fill()
1014                                .visualization_only(true)
1015                                .into_any_element()
1016                            } else if let Some(bullet_index) = builder.next_bullet_index() {
1017                                div().child(format!("{}.", bullet_index)).into_any_element()
1018                            } else {
1019                                div().child("").into_any_element()
1020                            };
1021                            builder.push_div(
1022                                div()
1023                                    .when(!self.style.height_is_multiple_of_line_height, |el| {
1024                                        el.mb_1().gap_1().line_height(rems(1.3))
1025                                    })
1026                                    .h_flex()
1027                                    .items_start()
1028                                    .child(bullet),
1029                                range,
1030                                markdown_end,
1031                            );
1032                            // Without `w_0`, text doesn't wrap to the width of the container.
1033                            builder.push_div(div().flex_1().w_0(), range, markdown_end);
1034                        }
1035                        MarkdownTag::Emphasis => builder.push_text_style(TextStyleRefinement {
1036                            font_style: Some(FontStyle::Italic),
1037                            ..Default::default()
1038                        }),
1039                        MarkdownTag::Strong => builder.push_text_style(TextStyleRefinement {
1040                            font_weight: Some(FontWeight::BOLD),
1041                            ..Default::default()
1042                        }),
1043                        MarkdownTag::Strikethrough => {
1044                            builder.push_text_style(TextStyleRefinement {
1045                                strikethrough: Some(StrikethroughStyle {
1046                                    thickness: px(1.),
1047                                    color: None,
1048                                }),
1049                                ..Default::default()
1050                            })
1051                        }
1052                        MarkdownTag::Link { dest_url, .. } => {
1053                            if builder.code_block_stack.is_empty() {
1054                                builder.push_link(dest_url.clone(), range.clone());
1055                                let style = self
1056                                    .style
1057                                    .link_callback
1058                                    .as_ref()
1059                                    .and_then(|callback| callback(dest_url, cx))
1060                                    .unwrap_or_else(|| self.style.link.clone());
1061                                builder.push_text_style(style)
1062                            }
1063                        }
1064                        MarkdownTag::MetadataBlock(_) => {}
1065                        MarkdownTag::Table(alignments) => {
1066                            builder.table.start(alignments.clone());
1067
1068                            let column_count = alignments.len();
1069                            builder.push_div(
1070                                div()
1071                                    .id(("table", range.start))
1072                                    .grid()
1073                                    .grid_cols(column_count as u16)
1074                                    .when(self.style.table_columns_min_size, |this| {
1075                                        this.grid_cols_min_content(column_count as u16)
1076                                    })
1077                                    .when(!self.style.table_columns_min_size, |this| {
1078                                        this.grid_cols(column_count as u16)
1079                                    })
1080                                    .size_full()
1081                                    .mb_2()
1082                                    .border(px(1.5))
1083                                    .border_color(cx.theme().colors().border)
1084                                    .rounded_sm()
1085                                    .overflow_hidden(),
1086                                range,
1087                                markdown_end,
1088                            );
1089                        }
1090                        MarkdownTag::TableHead => {
1091                            builder.table.start_head();
1092                            builder.push_text_style(TextStyleRefinement {
1093                                font_weight: Some(FontWeight::SEMIBOLD),
1094                                ..Default::default()
1095                            });
1096                        }
1097                        MarkdownTag::TableRow => {
1098                            builder.table.start_row();
1099                        }
1100                        MarkdownTag::TableCell => {
1101                            let is_header = builder.table.in_head;
1102                            let row_index = builder.table.row_index;
1103                            let col_index = builder.table.col_index;
1104
1105                            builder.push_div(
1106                                div()
1107                                    .when(col_index > 0, |this| this.border_l_1())
1108                                    .when(row_index > 0, |this| this.border_t_1())
1109                                    .border_color(cx.theme().colors().border)
1110                                    .px_1()
1111                                    .py_0p5()
1112                                    .when(is_header, |this| {
1113                                        this.bg(cx.theme().colors().title_bar_background)
1114                                    })
1115                                    .when(!is_header && row_index % 2 == 1, |this| {
1116                                        this.bg(cx.theme().colors().panel_background)
1117                                    }),
1118                                range,
1119                                markdown_end,
1120                            );
1121                        }
1122                        _ => log::debug!("unsupported markdown tag {:?}", tag),
1123                    }
1124                }
1125                MarkdownEvent::End(tag) => match tag {
1126                    MarkdownTagEnd::Image => {
1127                        current_img_block_range.take();
1128                    }
1129                    MarkdownTagEnd::Paragraph => {
1130                        builder.pop_div();
1131                    }
1132                    MarkdownTagEnd::Heading(_) => {
1133                        builder.pop_div();
1134                        builder.pop_text_style()
1135                    }
1136                    MarkdownTagEnd::BlockQuote(_kind) => {
1137                        builder.pop_text_style();
1138                        builder.pop_div()
1139                    }
1140                    MarkdownTagEnd::CodeBlock => {
1141                        builder.trim_trailing_newline();
1142
1143                        builder.pop_div();
1144                        builder.pop_code_block();
1145                        builder.pop_text_style();
1146
1147                        if let CodeBlockRenderer::Default {
1148                            copy_button: true, ..
1149                        } = &self.code_block_renderer
1150                        {
1151                            builder.modify_current_div(|el| {
1152                                let content_range = parser::extract_code_block_content_range(
1153                                    &parsed_markdown.source()[range.clone()],
1154                                );
1155                                let content_range = content_range.start + range.start
1156                                    ..content_range.end + range.start;
1157
1158                                let code = parsed_markdown.source()[content_range].to_string();
1159                                let codeblock = render_copy_code_block_button(
1160                                    range.end,
1161                                    code,
1162                                    self.markdown.clone(),
1163                                    cx,
1164                                );
1165                                el.child(
1166                                    h_flex()
1167                                        .w_4()
1168                                        .absolute()
1169                                        .top_1p5()
1170                                        .right_1p5()
1171                                        .justify_end()
1172                                        .child(codeblock),
1173                                )
1174                            });
1175                        }
1176
1177                        if let CodeBlockRenderer::Default {
1178                            copy_button_on_hover: true,
1179                            ..
1180                        } = &self.code_block_renderer
1181                        {
1182                            builder.modify_current_div(|el| {
1183                                let content_range = parser::extract_code_block_content_range(
1184                                    &parsed_markdown.source()[range.clone()],
1185                                );
1186                                let content_range = content_range.start + range.start
1187                                    ..content_range.end + range.start;
1188
1189                                let code = parsed_markdown.source()[content_range].to_string();
1190                                let codeblock = render_copy_code_block_button(
1191                                    range.end,
1192                                    code,
1193                                    self.markdown.clone(),
1194                                    cx,
1195                                );
1196                                el.child(
1197                                    h_flex()
1198                                        .w_4()
1199                                        .absolute()
1200                                        .top_0()
1201                                        .right_0()
1202                                        .justify_end()
1203                                        .visible_on_hover("code_block")
1204                                        .child(codeblock),
1205                                )
1206                            });
1207                        }
1208
1209                        // Pop the parent container.
1210                        builder.pop_div();
1211                    }
1212                    MarkdownTagEnd::HtmlBlock => builder.pop_div(),
1213                    MarkdownTagEnd::List(_) => {
1214                        builder.pop_list();
1215                        builder.pop_div();
1216                    }
1217                    MarkdownTagEnd::Item => {
1218                        builder.pop_div();
1219                        builder.pop_div();
1220                    }
1221                    MarkdownTagEnd::Emphasis => builder.pop_text_style(),
1222                    MarkdownTagEnd::Strong => builder.pop_text_style(),
1223                    MarkdownTagEnd::Strikethrough => builder.pop_text_style(),
1224                    MarkdownTagEnd::Link => {
1225                        if builder.code_block_stack.is_empty() {
1226                            builder.pop_text_style()
1227                        }
1228                    }
1229                    MarkdownTagEnd::Table => {
1230                        builder.pop_div();
1231                        builder.table.end();
1232                    }
1233                    MarkdownTagEnd::TableHead => {
1234                        builder.pop_text_style();
1235                        builder.table.end_head();
1236                    }
1237                    MarkdownTagEnd::TableRow => {
1238                        builder.table.end_row();
1239                    }
1240                    MarkdownTagEnd::TableCell => {
1241                        builder.pop_div();
1242                        builder.table.end_cell();
1243                    }
1244                    _ => log::debug!("unsupported markdown tag end: {:?}", tag),
1245                },
1246                MarkdownEvent::Text => {
1247                    builder.push_text(&parsed_markdown.source[range.clone()], range.clone());
1248                }
1249                MarkdownEvent::SubstitutedText(text) => {
1250                    builder.push_text(text, range.clone());
1251                }
1252                MarkdownEvent::Code => {
1253                    builder.push_text_style(self.style.inline_code.clone());
1254                    builder.push_text(&parsed_markdown.source[range.clone()], range.clone());
1255                    builder.pop_text_style();
1256                }
1257                MarkdownEvent::Html => {
1258                    let html = &parsed_markdown.source[range.clone()];
1259                    if html.starts_with("<!--") {
1260                        builder.html_comment = true;
1261                    }
1262                    if html.trim_end().ends_with("-->") {
1263                        builder.html_comment = false;
1264                        continue;
1265                    }
1266                    if builder.html_comment {
1267                        continue;
1268                    }
1269                    builder.push_text(html, range.clone());
1270                }
1271                MarkdownEvent::InlineHtml => {
1272                    let html = &parsed_markdown.source[range.clone()];
1273                    if html.starts_with("<code>") {
1274                        builder.push_text_style(self.style.inline_code.clone());
1275                        continue;
1276                    }
1277                    if html.trim_end().starts_with("</code>") {
1278                        builder.pop_text_style();
1279                        continue;
1280                    }
1281                    builder.push_text(&parsed_markdown.source[range.clone()], range.clone());
1282                }
1283                MarkdownEvent::Rule => {
1284                    builder.push_div(
1285                        div()
1286                            .border_b_1()
1287                            .my_2()
1288                            .border_color(self.style.rule_color),
1289                        range,
1290                        markdown_end,
1291                    );
1292                    builder.pop_div()
1293                }
1294                MarkdownEvent::SoftBreak => builder.push_text(" ", range.clone()),
1295                MarkdownEvent::HardBreak => builder.push_text("\n", range.clone()),
1296                MarkdownEvent::TaskListMarker(_) => {
1297                    // handled inside the `MarkdownTag::Item` case
1298                }
1299                _ => log::debug!("unsupported markdown event {:?}", event),
1300            }
1301        }
1302        if self.style.code_block_overflow_x_scroll {
1303            let code_block_ids = code_block_ids;
1304            self.markdown.update(cx, move |markdown, _| {
1305                markdown.retain_code_block_scroll_handles(&code_block_ids);
1306            });
1307        } else {
1308            self.markdown
1309                .update(cx, |markdown, _| markdown.clear_code_block_scroll_handles());
1310        }
1311        let mut rendered_markdown = builder.build();
1312        let child_layout_id = rendered_markdown.element.request_layout(window, cx);
1313        let layout_id = window.request_layout(gpui::Style::default(), [child_layout_id], cx);
1314        (layout_id, rendered_markdown)
1315    }
1316
1317    fn prepaint(
1318        &mut self,
1319        _id: Option<&GlobalElementId>,
1320        _inspector_id: Option<&gpui::InspectorElementId>,
1321        bounds: Bounds<Pixels>,
1322        rendered_markdown: &mut Self::RequestLayoutState,
1323        window: &mut Window,
1324        cx: &mut App,
1325    ) -> Self::PrepaintState {
1326        let focus_handle = self.markdown.read(cx).focus_handle.clone();
1327        window.set_focus_handle(&focus_handle, cx);
1328        window.set_view_id(self.markdown.entity_id());
1329
1330        let hitbox = window.insert_hitbox(bounds, HitboxBehavior::Normal);
1331        rendered_markdown.element.prepaint(window, cx);
1332        self.autoscroll(&rendered_markdown.text, window, cx);
1333        hitbox
1334    }
1335
1336    fn paint(
1337        &mut self,
1338        _id: Option<&GlobalElementId>,
1339        _inspector_id: Option<&gpui::InspectorElementId>,
1340        bounds: Bounds<Pixels>,
1341        rendered_markdown: &mut Self::RequestLayoutState,
1342        hitbox: &mut Self::PrepaintState,
1343        window: &mut Window,
1344        cx: &mut App,
1345    ) {
1346        let mut context = KeyContext::default();
1347        context.add("Markdown");
1348        window.set_key_context(context);
1349        window.on_action(std::any::TypeId::of::<crate::Copy>(), {
1350            let entity = self.markdown.clone();
1351            let text = rendered_markdown.text.clone();
1352            move |_, phase, window, cx| {
1353                let text = text.clone();
1354                if phase == DispatchPhase::Bubble {
1355                    entity.update(cx, move |this, cx| this.copy(&text, window, cx))
1356                }
1357            }
1358        });
1359
1360        self.paint_mouse_listeners(hitbox, &rendered_markdown.text, window, cx);
1361        rendered_markdown.element.paint(window, cx);
1362        self.paint_selection(bounds, &rendered_markdown.text, window, cx);
1363    }
1364}
1365
1366fn apply_heading_style(
1367    mut heading: Div,
1368    level: pulldown_cmark::HeadingLevel,
1369    custom_styles: Option<&HeadingLevelStyles>,
1370) -> Div {
1371    heading = match level {
1372        pulldown_cmark::HeadingLevel::H1 => heading.text_3xl(),
1373        pulldown_cmark::HeadingLevel::H2 => heading.text_2xl(),
1374        pulldown_cmark::HeadingLevel::H3 => heading.text_xl(),
1375        pulldown_cmark::HeadingLevel::H4 => heading.text_lg(),
1376        pulldown_cmark::HeadingLevel::H5 => heading.text_base(),
1377        pulldown_cmark::HeadingLevel::H6 => heading.text_sm(),
1378    };
1379
1380    if let Some(styles) = custom_styles {
1381        let style_opt = match level {
1382            pulldown_cmark::HeadingLevel::H1 => &styles.h1,
1383            pulldown_cmark::HeadingLevel::H2 => &styles.h2,
1384            pulldown_cmark::HeadingLevel::H3 => &styles.h3,
1385            pulldown_cmark::HeadingLevel::H4 => &styles.h4,
1386            pulldown_cmark::HeadingLevel::H5 => &styles.h5,
1387            pulldown_cmark::HeadingLevel::H6 => &styles.h6,
1388        };
1389
1390        if let Some(style) = style_opt {
1391            heading.style().text = style.clone();
1392        }
1393    }
1394
1395    heading
1396}
1397
1398fn render_copy_code_block_button(
1399    id: usize,
1400    code: String,
1401    markdown: Entity<Markdown>,
1402    cx: &App,
1403) -> impl IntoElement {
1404    let id = ElementId::named_usize("copy-markdown-code", id);
1405    let was_copied = markdown.read(cx).copied_code_blocks.contains(&id);
1406    IconButton::new(
1407        id.clone(),
1408        if was_copied {
1409            IconName::Check
1410        } else {
1411            IconName::Copy
1412        },
1413    )
1414    .icon_color(Color::Muted)
1415    .icon_size(IconSize::Small)
1416    .style(ButtonStyle::Filled)
1417    .shape(ui::IconButtonShape::Square)
1418    .tooltip(Tooltip::text("Copy"))
1419    .on_click({
1420        let markdown = markdown;
1421        move |_event, _window, cx| {
1422            let id = id.clone();
1423            markdown.update(cx, |this, cx| {
1424                this.copied_code_blocks.insert(id.clone());
1425
1426                cx.write_to_clipboard(ClipboardItem::new_string(code.clone()));
1427
1428                cx.spawn(async move |this, cx| {
1429                    cx.background_executor().timer(Duration::from_secs(2)).await;
1430
1431                    cx.update(|cx| {
1432                        this.update(cx, |this, cx| {
1433                            this.copied_code_blocks.remove(&id);
1434                            cx.notify();
1435                        })
1436                    })
1437                    .ok();
1438                })
1439                .detach();
1440            });
1441        }
1442    })
1443}
1444
1445impl IntoElement for MarkdownElement {
1446    type Element = Self;
1447
1448    fn into_element(self) -> Self::Element {
1449        self
1450    }
1451}
1452
1453pub enum AnyDiv {
1454    Div(Div),
1455    Stateful(Stateful<Div>),
1456}
1457
1458impl AnyDiv {
1459    fn into_any_element(self) -> AnyElement {
1460        match self {
1461            Self::Div(div) => div.into_any_element(),
1462            Self::Stateful(div) => div.into_any_element(),
1463        }
1464    }
1465}
1466
1467impl From<Div> for AnyDiv {
1468    fn from(value: Div) -> Self {
1469        Self::Div(value)
1470    }
1471}
1472
1473impl From<Stateful<Div>> for AnyDiv {
1474    fn from(value: Stateful<Div>) -> Self {
1475        Self::Stateful(value)
1476    }
1477}
1478
1479impl Styled for AnyDiv {
1480    fn style(&mut self) -> &mut StyleRefinement {
1481        match self {
1482            Self::Div(div) => div.style(),
1483            Self::Stateful(div) => div.style(),
1484        }
1485    }
1486}
1487
1488impl ParentElement for AnyDiv {
1489    fn extend(&mut self, elements: impl IntoIterator<Item = AnyElement>) {
1490        match self {
1491            Self::Div(div) => div.extend(elements),
1492            Self::Stateful(div) => div.extend(elements),
1493        }
1494    }
1495}
1496
1497#[derive(Default)]
1498struct TableState {
1499    alignments: Vec<Alignment>,
1500    in_head: bool,
1501    row_index: usize,
1502    col_index: usize,
1503}
1504
1505impl TableState {
1506    fn start(&mut self, alignments: Vec<Alignment>) {
1507        self.alignments = alignments;
1508        self.in_head = false;
1509        self.row_index = 0;
1510        self.col_index = 0;
1511    }
1512
1513    fn end(&mut self) {
1514        self.alignments.clear();
1515        self.in_head = false;
1516        self.row_index = 0;
1517        self.col_index = 0;
1518    }
1519
1520    fn start_head(&mut self) {
1521        self.in_head = true;
1522    }
1523
1524    fn end_head(&mut self) {
1525        self.in_head = false;
1526    }
1527
1528    fn start_row(&mut self) {
1529        self.col_index = 0;
1530    }
1531
1532    fn end_row(&mut self) {
1533        self.row_index += 1;
1534    }
1535
1536    fn end_cell(&mut self) {
1537        self.col_index += 1;
1538    }
1539}
1540
1541struct MarkdownElementBuilder {
1542    div_stack: Vec<AnyDiv>,
1543    rendered_lines: Vec<RenderedLine>,
1544    pending_line: PendingLine,
1545    rendered_links: Vec<RenderedLink>,
1546    current_source_index: usize,
1547    html_comment: bool,
1548    base_text_style: TextStyle,
1549    text_style_stack: Vec<TextStyleRefinement>,
1550    code_block_stack: Vec<Option<Arc<Language>>>,
1551    list_stack: Vec<ListStackEntry>,
1552    table: TableState,
1553    syntax_theme: Arc<SyntaxTheme>,
1554}
1555
1556#[derive(Default)]
1557struct PendingLine {
1558    text: String,
1559    runs: Vec<TextRun>,
1560    source_mappings: Vec<SourceMapping>,
1561}
1562
1563struct ListStackEntry {
1564    bullet_index: Option<u64>,
1565}
1566
1567impl MarkdownElementBuilder {
1568    fn new(
1569        container_style: &StyleRefinement,
1570        base_text_style: TextStyle,
1571        syntax_theme: Arc<SyntaxTheme>,
1572    ) -> Self {
1573        Self {
1574            div_stack: vec![{
1575                let mut base_div = div();
1576                base_div.style().refine(container_style);
1577                base_div.debug_selector(|| "inner".into()).into()
1578            }],
1579            rendered_lines: Vec::new(),
1580            pending_line: PendingLine::default(),
1581            rendered_links: Vec::new(),
1582            current_source_index: 0,
1583            html_comment: false,
1584            base_text_style,
1585            text_style_stack: Vec::new(),
1586            code_block_stack: Vec::new(),
1587            list_stack: Vec::new(),
1588            table: TableState::default(),
1589            syntax_theme,
1590        }
1591    }
1592
1593    fn push_text_style(&mut self, style: TextStyleRefinement) {
1594        self.text_style_stack.push(style);
1595    }
1596
1597    fn text_style(&self) -> TextStyle {
1598        let mut style = self.base_text_style.clone();
1599        for refinement in &self.text_style_stack {
1600            style.refine(refinement);
1601        }
1602        style
1603    }
1604
1605    fn pop_text_style(&mut self) {
1606        self.text_style_stack.pop();
1607    }
1608
1609    fn push_div(&mut self, div: impl Into<AnyDiv>, range: &Range<usize>, markdown_end: usize) {
1610        let mut div = div.into();
1611        self.flush_text();
1612
1613        if range.start == 0 {
1614            // Remove the top margin on the first element.
1615            div.style().refine(&StyleRefinement {
1616                margin: gpui::EdgesRefinement {
1617                    top: Some(Length::Definite(px(0.).into())),
1618                    left: None,
1619                    right: None,
1620                    bottom: None,
1621                },
1622                ..Default::default()
1623            });
1624        }
1625
1626        if range.end == markdown_end {
1627            div.style().refine(&StyleRefinement {
1628                margin: gpui::EdgesRefinement {
1629                    top: None,
1630                    left: None,
1631                    right: None,
1632                    bottom: Some(Length::Definite(rems(0.).into())),
1633                },
1634                ..Default::default()
1635            });
1636        }
1637
1638        self.div_stack.push(div);
1639    }
1640
1641    fn modify_current_div(&mut self, f: impl FnOnce(AnyDiv) -> AnyDiv) {
1642        self.flush_text();
1643        if let Some(div) = self.div_stack.pop() {
1644            self.div_stack.push(f(div));
1645        }
1646    }
1647
1648    fn pop_div(&mut self) {
1649        self.flush_text();
1650        let div = self.div_stack.pop().unwrap().into_any_element();
1651        self.div_stack.last_mut().unwrap().extend(iter::once(div));
1652    }
1653
1654    fn push_list(&mut self, bullet_index: Option<u64>) {
1655        self.list_stack.push(ListStackEntry { bullet_index });
1656    }
1657
1658    fn next_bullet_index(&mut self) -> Option<u64> {
1659        self.list_stack.last_mut().and_then(|entry| {
1660            let item_index = entry.bullet_index.as_mut()?;
1661            *item_index += 1;
1662            Some(*item_index - 1)
1663        })
1664    }
1665
1666    fn pop_list(&mut self) {
1667        self.list_stack.pop();
1668    }
1669
1670    fn push_code_block(&mut self, language: Option<Arc<Language>>) {
1671        self.code_block_stack.push(language);
1672    }
1673
1674    fn pop_code_block(&mut self) {
1675        self.code_block_stack.pop();
1676    }
1677
1678    fn push_link(&mut self, destination_url: SharedString, source_range: Range<usize>) {
1679        self.rendered_links.push(RenderedLink {
1680            source_range,
1681            destination_url,
1682        });
1683    }
1684
1685    fn push_text(&mut self, text: &str, source_range: Range<usize>) {
1686        self.pending_line.source_mappings.push(SourceMapping {
1687            rendered_index: self.pending_line.text.len(),
1688            source_index: source_range.start,
1689        });
1690        self.pending_line.text.push_str(text);
1691        self.current_source_index = source_range.end;
1692
1693        if let Some(Some(language)) = self.code_block_stack.last() {
1694            let mut offset = 0;
1695            for (range, highlight_id) in language.highlight_text(&Rope::from(text), 0..text.len()) {
1696                if range.start > offset {
1697                    self.pending_line
1698                        .runs
1699                        .push(self.text_style().to_run(range.start - offset));
1700                }
1701
1702                let mut run_style = self.text_style();
1703                if let Some(highlight) = highlight_id.style(&self.syntax_theme) {
1704                    run_style = run_style.highlight(highlight);
1705                }
1706                self.pending_line.runs.push(run_style.to_run(range.len()));
1707                offset = range.end;
1708            }
1709
1710            if offset < text.len() {
1711                self.pending_line
1712                    .runs
1713                    .push(self.text_style().to_run(text.len() - offset));
1714            }
1715        } else {
1716            self.pending_line
1717                .runs
1718                .push(self.text_style().to_run(text.len()));
1719        }
1720    }
1721
1722    fn trim_trailing_newline(&mut self) {
1723        if self.pending_line.text.ends_with('\n') {
1724            self.pending_line
1725                .text
1726                .truncate(self.pending_line.text.len() - 1);
1727            self.pending_line.runs.last_mut().unwrap().len -= 1;
1728            self.current_source_index -= 1;
1729        }
1730    }
1731
1732    fn flush_text(&mut self) {
1733        let line = mem::take(&mut self.pending_line);
1734        if line.text.is_empty() {
1735            return;
1736        }
1737
1738        let text = StyledText::new(line.text).with_runs(line.runs);
1739        self.rendered_lines.push(RenderedLine {
1740            layout: text.layout().clone(),
1741            source_mappings: line.source_mappings,
1742            source_end: self.current_source_index,
1743        });
1744        self.div_stack.last_mut().unwrap().extend([text.into_any()]);
1745    }
1746
1747    fn build(mut self) -> RenderedMarkdown {
1748        debug_assert_eq!(self.div_stack.len(), 1);
1749        self.flush_text();
1750        RenderedMarkdown {
1751            element: self.div_stack.pop().unwrap().into_any_element(),
1752            text: RenderedText {
1753                lines: self.rendered_lines.into(),
1754                links: self.rendered_links.into(),
1755            },
1756        }
1757    }
1758}
1759
1760struct RenderedLine {
1761    layout: TextLayout,
1762    source_mappings: Vec<SourceMapping>,
1763    source_end: usize,
1764}
1765
1766impl RenderedLine {
1767    fn rendered_index_for_source_index(&self, source_index: usize) -> usize {
1768        if source_index >= self.source_end {
1769            return self.layout.len();
1770        }
1771
1772        let mapping = match self
1773            .source_mappings
1774            .binary_search_by_key(&source_index, |probe| probe.source_index)
1775        {
1776            Ok(ix) => &self.source_mappings[ix],
1777            Err(ix) => &self.source_mappings[ix - 1],
1778        };
1779        mapping.rendered_index + (source_index - mapping.source_index)
1780    }
1781
1782    fn source_index_for_rendered_index(&self, rendered_index: usize) -> usize {
1783        if rendered_index >= self.layout.len() {
1784            return self.source_end;
1785        }
1786
1787        let mapping = match self
1788            .source_mappings
1789            .binary_search_by_key(&rendered_index, |probe| probe.rendered_index)
1790        {
1791            Ok(ix) => &self.source_mappings[ix],
1792            Err(ix) => &self.source_mappings[ix - 1],
1793        };
1794        mapping.source_index + (rendered_index - mapping.rendered_index)
1795    }
1796
1797    fn source_index_for_position(&self, position: Point<Pixels>) -> Result<usize, usize> {
1798        let line_rendered_index;
1799        let out_of_bounds;
1800        match self.layout.index_for_position(position) {
1801            Ok(ix) => {
1802                line_rendered_index = ix;
1803                out_of_bounds = false;
1804            }
1805            Err(ix) => {
1806                line_rendered_index = ix;
1807                out_of_bounds = true;
1808            }
1809        };
1810        let source_index = self.source_index_for_rendered_index(line_rendered_index);
1811        if out_of_bounds {
1812            Err(source_index)
1813        } else {
1814            Ok(source_index)
1815        }
1816    }
1817}
1818
1819#[derive(Copy, Clone, Debug, Default)]
1820struct SourceMapping {
1821    rendered_index: usize,
1822    source_index: usize,
1823}
1824
1825pub struct RenderedMarkdown {
1826    element: AnyElement,
1827    text: RenderedText,
1828}
1829
1830#[derive(Clone)]
1831struct RenderedText {
1832    lines: Rc<[RenderedLine]>,
1833    links: Rc<[RenderedLink]>,
1834}
1835
1836#[derive(Debug, Clone, Eq, PartialEq)]
1837struct RenderedLink {
1838    source_range: Range<usize>,
1839    destination_url: SharedString,
1840}
1841
1842impl RenderedText {
1843    fn source_index_for_position(&self, position: Point<Pixels>) -> Result<usize, usize> {
1844        let mut lines = self.lines.iter().peekable();
1845
1846        while let Some(line) = lines.next() {
1847            let line_bounds = line.layout.bounds();
1848            if position.y > line_bounds.bottom() {
1849                if let Some(next_line) = lines.peek()
1850                    && position.y < next_line.layout.bounds().top()
1851                {
1852                    return Err(line.source_end);
1853                }
1854
1855                continue;
1856            }
1857
1858            return line.source_index_for_position(position);
1859        }
1860
1861        Err(self.lines.last().map_or(0, |line| line.source_end))
1862    }
1863
1864    fn position_for_source_index(&self, source_index: usize) -> Option<(Point<Pixels>, Pixels)> {
1865        for line in self.lines.iter() {
1866            let line_source_start = line.source_mappings.first().unwrap().source_index;
1867            if source_index < line_source_start {
1868                break;
1869            } else if source_index > line.source_end {
1870                continue;
1871            } else {
1872                let line_height = line.layout.line_height();
1873                let rendered_index_within_line = line.rendered_index_for_source_index(source_index);
1874                let position = line.layout.position_for_index(rendered_index_within_line)?;
1875                return Some((position, line_height));
1876            }
1877        }
1878        None
1879    }
1880
1881    fn surrounding_word_range(&self, source_index: usize) -> Range<usize> {
1882        for line in self.lines.iter() {
1883            if source_index > line.source_end {
1884                continue;
1885            }
1886
1887            let line_rendered_start = line.source_mappings.first().unwrap().rendered_index;
1888            let rendered_index_in_line =
1889                line.rendered_index_for_source_index(source_index) - line_rendered_start;
1890            let text = line.layout.text();
1891            let previous_space = if let Some(idx) = text[0..rendered_index_in_line].rfind(' ') {
1892                idx + ' '.len_utf8()
1893            } else {
1894                0
1895            };
1896            let next_space = if let Some(idx) = text[rendered_index_in_line..].find(' ') {
1897                rendered_index_in_line + idx
1898            } else {
1899                text.len()
1900            };
1901
1902            return line.source_index_for_rendered_index(line_rendered_start + previous_space)
1903                ..line.source_index_for_rendered_index(line_rendered_start + next_space);
1904        }
1905
1906        source_index..source_index
1907    }
1908
1909    fn surrounding_line_range(&self, source_index: usize) -> Range<usize> {
1910        for line in self.lines.iter() {
1911            if source_index > line.source_end {
1912                continue;
1913            }
1914            let line_source_start = line.source_mappings.first().unwrap().source_index;
1915            return line_source_start..line.source_end;
1916        }
1917
1918        source_index..source_index
1919    }
1920
1921    fn text_for_range(&self, range: Range<usize>) -> String {
1922        let mut accumulator = String::new();
1923
1924        for line in self.lines.iter() {
1925            if range.start > line.source_end {
1926                continue;
1927            }
1928            let line_source_start = line.source_mappings.first().unwrap().source_index;
1929            if range.end < line_source_start {
1930                break;
1931            }
1932
1933            let text = line.layout.text();
1934
1935            let start = if range.start < line_source_start {
1936                0
1937            } else {
1938                line.rendered_index_for_source_index(range.start)
1939            };
1940            let end = if range.end > line.source_end {
1941                line.rendered_index_for_source_index(line.source_end)
1942            } else {
1943                line.rendered_index_for_source_index(range.end)
1944            }
1945            .min(text.len());
1946
1947            accumulator.push_str(&text[start..end]);
1948            accumulator.push('\n');
1949        }
1950        // Remove trailing newline
1951        accumulator.pop();
1952        accumulator
1953    }
1954
1955    fn link_for_position(&self, position: Point<Pixels>) -> Option<&RenderedLink> {
1956        let source_index = self.source_index_for_position(position).ok()?;
1957        self.links
1958            .iter()
1959            .find(|link| link.source_range.contains(&source_index))
1960    }
1961}
1962
1963#[cfg(test)]
1964mod tests {
1965    use super::*;
1966    use gpui::{TestAppContext, size};
1967
1968    #[gpui::test]
1969    fn test_mappings(cx: &mut TestAppContext) {
1970        // Formatting.
1971        assert_mappings(
1972            &render_markdown("He*l*lo", cx),
1973            vec![vec![(0, 0), (1, 1), (2, 3), (3, 5), (4, 6), (5, 7)]],
1974        );
1975
1976        // Multiple lines.
1977        assert_mappings(
1978            &render_markdown("Hello\n\nWorld", cx),
1979            vec![
1980                vec![(0, 0), (1, 1), (2, 2), (3, 3), (4, 4), (5, 5)],
1981                vec![(0, 7), (1, 8), (2, 9), (3, 10), (4, 11), (5, 12)],
1982            ],
1983        );
1984
1985        // Multi-byte characters.
1986        assert_mappings(
1987            &render_markdown("αβγ\n\nδεζ", cx),
1988            vec![
1989                vec![(0, 0), (2, 2), (4, 4), (6, 6)],
1990                vec![(0, 8), (2, 10), (4, 12), (6, 14)],
1991            ],
1992        );
1993
1994        // Smart quotes.
1995        assert_mappings(&render_markdown("\"", cx), vec![vec![(0, 0), (3, 1)]]);
1996        assert_mappings(
1997            &render_markdown("\"hey\"", cx),
1998            vec![vec![(0, 0), (3, 1), (4, 2), (5, 3), (6, 4), (9, 5)]],
1999        );
2000
2001        // HTML Comments are ignored
2002        assert_mappings(
2003            &render_markdown(
2004                "<!--\nrdoc-file=string.c\n- str.intern   -> symbol\n- str.to_sym   -> symbol\n-->\nReturns",
2005                cx,
2006            ),
2007            vec![vec![
2008                (0, 78),
2009                (1, 79),
2010                (2, 80),
2011                (3, 81),
2012                (4, 82),
2013                (5, 83),
2014                (6, 84),
2015            ]],
2016        );
2017    }
2018
2019    fn render_markdown(markdown: &str, cx: &mut TestAppContext) -> RenderedText {
2020        struct TestWindow;
2021
2022        impl Render for TestWindow {
2023            fn render(&mut self, _: &mut Window, _: &mut Context<Self>) -> impl IntoElement {
2024                div()
2025            }
2026        }
2027
2028        let (_, cx) = cx.add_window_view(|_, _| TestWindow);
2029        let markdown = cx.new(|cx| Markdown::new(markdown.to_string().into(), None, None, cx));
2030        cx.run_until_parked();
2031        let (rendered, _) = cx.draw(
2032            Default::default(),
2033            size(px(600.0), px(600.0)),
2034            |_window, _cx| MarkdownElement::new(markdown, MarkdownStyle::default()),
2035        );
2036        rendered.text
2037    }
2038
2039    #[gpui::test]
2040    fn test_surrounding_word_range(cx: &mut TestAppContext) {
2041        let rendered = render_markdown("Hello world tesεζ", cx);
2042
2043        // Test word selection for "Hello"
2044        let word_range = rendered.surrounding_word_range(2); // Simulate click on 'l' in "Hello"
2045        let selected_text = rendered.text_for_range(word_range);
2046        assert_eq!(selected_text, "Hello");
2047
2048        // Test word selection for "world"
2049        let word_range = rendered.surrounding_word_range(7); // Simulate click on 'o' in "world"
2050        let selected_text = rendered.text_for_range(word_range);
2051        assert_eq!(selected_text, "world");
2052
2053        // Test word selection for "tesεζ"
2054        let word_range = rendered.surrounding_word_range(14); // Simulate click on 's' in "tesεζ"
2055        let selected_text = rendered.text_for_range(word_range);
2056        assert_eq!(selected_text, "tesεζ");
2057
2058        // Test word selection at word boundary (space)
2059        let word_range = rendered.surrounding_word_range(5); // Simulate click on space between "Hello" and "world", expect highlighting word to the left
2060        let selected_text = rendered.text_for_range(word_range);
2061        assert_eq!(selected_text, "Hello");
2062    }
2063
2064    #[gpui::test]
2065    fn test_surrounding_line_range(cx: &mut TestAppContext) {
2066        let rendered = render_markdown("First line\n\nSecond line\n\nThird lineεζ", cx);
2067
2068        // Test getting line range for first line
2069        let line_range = rendered.surrounding_line_range(5); // Simulate click somewhere in first line
2070        let selected_text = rendered.text_for_range(line_range);
2071        assert_eq!(selected_text, "First line");
2072
2073        // Test getting line range for second line
2074        let line_range = rendered.surrounding_line_range(13); // Simulate click at beginning in second line
2075        let selected_text = rendered.text_for_range(line_range);
2076        assert_eq!(selected_text, "Second line");
2077
2078        // Test getting line range for third line
2079        let line_range = rendered.surrounding_line_range(37); // Simulate click at end of third line with multi-byte chars
2080        let selected_text = rendered.text_for_range(line_range);
2081        assert_eq!(selected_text, "Third lineεζ");
2082    }
2083
2084    #[gpui::test]
2085    fn test_selection_head_movement(cx: &mut TestAppContext) {
2086        let rendered = render_markdown("Hello world test", cx);
2087
2088        let mut selection = Selection {
2089            start: 5,
2090            end: 5,
2091            reversed: false,
2092            pending: false,
2093            mode: SelectMode::Character,
2094        };
2095
2096        // Test forward selection
2097        selection.set_head(10, &rendered);
2098        assert_eq!(selection.start, 5);
2099        assert_eq!(selection.end, 10);
2100        assert!(!selection.reversed);
2101        assert_eq!(selection.tail(), 5);
2102
2103        // Test backward selection
2104        selection.set_head(2, &rendered);
2105        assert_eq!(selection.start, 2);
2106        assert_eq!(selection.end, 5);
2107        assert!(selection.reversed);
2108        assert_eq!(selection.tail(), 5);
2109
2110        // Test forward selection again from reversed state
2111        selection.set_head(15, &rendered);
2112        assert_eq!(selection.start, 5);
2113        assert_eq!(selection.end, 15);
2114        assert!(!selection.reversed);
2115        assert_eq!(selection.tail(), 5);
2116    }
2117
2118    #[gpui::test]
2119    fn test_word_selection_drag(cx: &mut TestAppContext) {
2120        let rendered = render_markdown("Hello world test", cx);
2121
2122        // Start with a simulated double-click on "world" (index 6-10)
2123        let word_range = rendered.surrounding_word_range(7); // Click on 'o' in "world"
2124        let mut selection = Selection {
2125            start: word_range.start,
2126            end: word_range.end,
2127            reversed: false,
2128            pending: true,
2129            mode: SelectMode::Word(word_range),
2130        };
2131
2132        // Drag forward to "test" - should expand selection to include "test"
2133        selection.set_head(13, &rendered); // Index in "test"
2134        assert_eq!(selection.start, 6); // Start of "world"
2135        assert_eq!(selection.end, 16); // End of "test"
2136        assert!(!selection.reversed);
2137        let selected_text = rendered.text_for_range(selection.start..selection.end);
2138        assert_eq!(selected_text, "world test");
2139
2140        // Drag backward to "Hello" - should expand selection to include "Hello"
2141        selection.set_head(2, &rendered); // Index in "Hello"
2142        assert_eq!(selection.start, 0); // Start of "Hello"
2143        assert_eq!(selection.end, 11); // End of "world" (original selection)
2144        assert!(selection.reversed);
2145        let selected_text = rendered.text_for_range(selection.start..selection.end);
2146        assert_eq!(selected_text, "Hello world");
2147
2148        // Drag back within original word - should revert to original selection
2149        selection.set_head(8, &rendered); // Back within "world"
2150        assert_eq!(selection.start, 6); // Start of "world"
2151        assert_eq!(selection.end, 11); // End of "world"
2152        assert!(!selection.reversed);
2153        let selected_text = rendered.text_for_range(selection.start..selection.end);
2154        assert_eq!(selected_text, "world");
2155    }
2156
2157    #[gpui::test]
2158    fn test_selection_with_markdown_formatting(cx: &mut TestAppContext) {
2159        let rendered = render_markdown(
2160            "This is **bold** text, this is *italic* text, use `code` here",
2161            cx,
2162        );
2163        let word_range = rendered.surrounding_word_range(10); // Inside "bold"
2164        let selected_text = rendered.text_for_range(word_range);
2165        assert_eq!(selected_text, "bold");
2166
2167        let word_range = rendered.surrounding_word_range(32); // Inside "italic"
2168        let selected_text = rendered.text_for_range(word_range);
2169        assert_eq!(selected_text, "italic");
2170
2171        let word_range = rendered.surrounding_word_range(51); // Inside "code"
2172        let selected_text = rendered.text_for_range(word_range);
2173        assert_eq!(selected_text, "code");
2174    }
2175
2176    #[gpui::test]
2177    fn test_all_selection(cx: &mut TestAppContext) {
2178        let rendered = render_markdown("Hello world\n\nThis is a test\n\nwith multiple lines", cx);
2179
2180        let total_length = rendered
2181            .lines
2182            .last()
2183            .map(|line| line.source_end)
2184            .unwrap_or(0);
2185
2186        let mut selection = Selection {
2187            start: 0,
2188            end: total_length,
2189            reversed: false,
2190            pending: true,
2191            mode: SelectMode::All,
2192        };
2193
2194        selection.set_head(5, &rendered); // Try to set head in middle
2195        assert_eq!(selection.start, 0);
2196        assert_eq!(selection.end, total_length);
2197        assert!(!selection.reversed);
2198
2199        selection.set_head(25, &rendered); // Try to set head near end
2200        assert_eq!(selection.start, 0);
2201        assert_eq!(selection.end, total_length);
2202        assert!(!selection.reversed);
2203
2204        let selected_text = rendered.text_for_range(selection.start..selection.end);
2205        assert_eq!(
2206            selected_text,
2207            "Hello world\nThis is a test\nwith multiple lines"
2208        );
2209    }
2210
2211    #[test]
2212    fn test_escape() {
2213        assert_eq!(Markdown::escape("hello `world`"), "hello \\`world\\`");
2214        assert_eq!(
2215            Markdown::escape("hello\n    cool world"),
2216            "hello\n\ncool world"
2217        );
2218    }
2219
2220    #[track_caller]
2221    fn assert_mappings(rendered: &RenderedText, expected: Vec<Vec<(usize, usize)>>) {
2222        assert_eq!(rendered.lines.len(), expected.len(), "line count mismatch");
2223        for (line_ix, line_mappings) in expected.into_iter().enumerate() {
2224            let line = &rendered.lines[line_ix];
2225
2226            assert!(
2227                line.source_mappings.windows(2).all(|mappings| {
2228                    mappings[0].source_index < mappings[1].source_index
2229                        && mappings[0].rendered_index < mappings[1].rendered_index
2230                }),
2231                "line {} has duplicate mappings: {:?}",
2232                line_ix,
2233                line.source_mappings
2234            );
2235
2236            for (rendered_ix, source_ix) in line_mappings {
2237                assert_eq!(
2238                    line.source_index_for_rendered_index(rendered_ix),
2239                    source_ix,
2240                    "line {}, rendered_ix {}",
2241                    line_ix,
2242                    rendered_ix
2243                );
2244
2245                assert_eq!(
2246                    line.rendered_index_for_source_index(source_ix),
2247                    rendered_ix,
2248                    "line {}, source_ix {}",
2249                    line_ix,
2250                    source_ix
2251                );
2252            }
2253        }
2254    }
2255}