Remove Markdown CodeBlock metadata and Custom rendering (#42211)

Xipeng Jin created 1 week ago

Follow up #40736

Clean up `CodeBlockRenderer::Custom` related rendering per the previous
PR
[comment](https://github.com/zed-industries/zed/pull/40736#issuecomment-3503074893).
Additional note here:
1. The `Custom` variant in the enum `CodeBlockRenderer` will become not
useful since cleaning all code related to the custom rendering logic.
2. Need to further review the usage of code block `metadata` field in
`MarkdownTag::CodeBlock` enum.

I would like to have the team further review my note above so that we
can make sure it will be safe to clean it up and will not affect any
potential future features will be built on top of it. Thank you!

Release Notes:

- N/A

Change summary

crates/markdown/src/markdown.rs | 82 ----------------------------------
1 file changed, 2 insertions(+), 80 deletions(-)

Detailed changes

crates/markdown/src/markdown.rs

@@ -787,7 +787,6 @@ impl Element for MarkdownElement {
         };
         let mut code_block_ids = HashSet::default();
 
-        let mut current_code_block_metadata = None;
         let mut current_img_block_range: Option<Range<usize>> = None;
         for (range, event) in parsed_markdown.events.iter() {
             // Skip alt text for images that rendered
@@ -849,7 +848,7 @@ impl Element for MarkdownElement {
                                 markdown_end,
                             );
                         }
-                        MarkdownTag::CodeBlock { kind, metadata } => {
+                        MarkdownTag::CodeBlock { kind, .. } => {
                             let language = match kind {
                                 CodeBlockKind::Fenced => None,
                                 CodeBlockKind::FencedLang(language) => {
@@ -862,8 +861,6 @@ impl Element for MarkdownElement {
                                 _ => None,
                             };
 
-                            current_code_block_metadata = Some(metadata.clone());
-
                             let is_indented = matches!(kind, CodeBlockKind::Indented);
                             let scroll_handle = if self.style.code_block_overflow_x_scroll {
                                 code_block_ids.insert(range.start);
@@ -935,64 +932,7 @@ impl Element for MarkdownElement {
                                     builder.push_code_block(language);
                                     builder.push_div(code_block, range, markdown_end);
                                 }
-                                (CodeBlockRenderer::Custom { render, .. }, _) => {
-                                    let parent_container = render(
-                                        kind,
-                                        &parsed_markdown,
-                                        range.clone(),
-                                        metadata.clone(),
-                                        window,
-                                        cx,
-                                    );
-
-                                    let mut parent_container: AnyDiv = if let Some(scroll_handle) =
-                                        scroll_handle.as_ref()
-                                    {
-                                        let scrollbars = Scrollbars::new(ScrollAxes::Horizontal)
-                                            .id(("markdown-code-block-scrollbar", range.start))
-                                            .tracked_scroll_handle(scroll_handle.clone())
-                                            .with_track_along(
-                                                ScrollAxes::Horizontal,
-                                                cx.theme().colors().editor_background,
-                                            )
-                                            .notify_content();
-
-                                        parent_container
-                                            .rounded_b_lg()
-                                            .custom_scrollbars(scrollbars, window, cx)
-                                            .into()
-                                    } else {
-                                        parent_container.into()
-                                    };
-
-                                    parent_container.style().refine(&self.style.code_block);
-                                    builder.push_div(parent_container, range, markdown_end);
-
-                                    let code_block = div()
-                                        .id(("code-block", range.start))
-                                        .rounded_b_lg()
-                                        .map(|mut code_block| {
-                                            if let Some(scroll_handle) = scroll_handle.as_ref() {
-                                                code_block.style().restrict_scroll_to_axis =
-                                                    Some(true);
-                                                code_block
-                                                    .flex()
-                                                    .overflow_x_scroll()
-                                                    .overflow_y_hidden()
-                                                    .track_scroll(scroll_handle)
-                                            } else {
-                                                code_block.w_full().overflow_hidden()
-                                            }
-                                        });
-
-                                    if let Some(code_block_text_style) = &self.style.code_block.text
-                                    {
-                                        builder.push_text_style(code_block_text_style.to_owned());
-                                    }
-
-                                    builder.push_code_block(language);
-                                    builder.push_div(code_block, range, markdown_end);
-                                }
+                                (CodeBlockRenderer::Custom { .. }, _) => {}
                             }
                         }
                         MarkdownTag::HtmlBlock => builder.push_div(div(), range, markdown_end),
@@ -1131,24 +1071,6 @@ impl Element for MarkdownElement {
                             builder.pop_text_style();
                         }
 
-                        let metadata = current_code_block_metadata.take();
-
-                        if let CodeBlockRenderer::Custom {
-                            transform: Some(transform),
-                            ..
-                        } = &self.code_block_renderer
-                        {
-                            builder.modify_current_div(|el| {
-                                transform(
-                                    el,
-                                    range.clone(),
-                                    metadata.clone().unwrap_or_default(),
-                                    window,
-                                    cx,
-                                )
-                            });
-                        }
-
                         if let CodeBlockRenderer::Default {
                             copy_button: true, ..
                         } = &self.code_block_renderer