Add SVG preview (#32694)

Closes #10454

Implements SVG file preview capability similar to the existing markdown
preview.
- Adds `svg_preview` crate with preview view and live reloading upon
file save.
- Integrates SVG preview button in quick action bar.
- File preview shortcuts (`ctrl/cmd+k v` and `ctrl/cmd+shift+v`) are
extension-aware.

Release Notes:

- Added SVG file preview, accessible via the quick action bar button or
keyboard shortcuts (`ctrl/cmd+k v` and `ctrl/cmd+shift+v`) when editing
SVG files.

crates/markdown_preview/src/markdown_preview_view.rs

@@ -17,10 +17,9 @@ use ui::prelude::*;
 use workspace::item::{Item, ItemHandle};
 use workspace::{Pane, Workspace};
 
-use crate::OpenPreviewToTheSide;
 use crate::markdown_elements::ParsedMarkdownElement;
 use crate::{
-    OpenFollowingPreview, OpenPreview,
+    OpenFollowingPreview, OpenPreview, OpenPreviewToTheSide,
     markdown_elements::ParsedMarkdown,
     markdown_parser::parse_markdown,
     markdown_renderer::{RenderContext, render_markdown_block},
@@ -36,7 +35,6 @@ pub struct MarkdownPreviewView {
     contents: Option<ParsedMarkdown>,
     selected_block: usize,
     list_state: ListState,
-    tab_content_text: Option<SharedString>,
     language_registry: Arc<LanguageRegistry>,
     parsing_markdown_task: Option<Task<Result<()>>>,
     mode: MarkdownPreviewMode,
@@ -173,7 +171,6 @@ impl MarkdownPreviewView {
             editor,
             workspace_handle,
             language_registry,
-            None,
             window,
             cx,
         )
@@ -192,7 +189,6 @@ impl MarkdownPreviewView {
             editor,
             workspace_handle,
             language_registry,
-            None,
             window,
             cx,
         )
@@ -203,7 +199,6 @@ impl MarkdownPreviewView {
         active_editor: Entity<Editor>,
         workspace: WeakEntity<Workspace>,
         language_registry: Arc<LanguageRegistry>,
-        tab_content_text: Option<SharedString>,
         window: &mut Window,
         cx: &mut Context<Workspace>,
     ) -> Entity<Self> {
@@ -324,7 +319,6 @@ impl MarkdownPreviewView {
                 workspace: workspace.clone(),
                 contents: None,
                 list_state,
-                tab_content_text,
                 language_registry,
                 parsing_markdown_task: None,
                 image_cache: RetainAllImageCache::new(cx),
@@ -405,12 +399,6 @@ impl MarkdownPreviewView {
             },
         );
 
-        let tab_content = editor.read(cx).tab_content_text(0, cx);
-
-        if self.tab_content_text.is_none() {
-            self.tab_content_text = Some(format!("Preview {}", tab_content).into());
-        }
-
         self.active_editor = Some(EditorState {
             editor,
             _subscription: subscription,
@@ -547,21 +535,28 @@ impl Focusable for MarkdownPreviewView {
     }
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub enum PreviewEvent {}
-
-impl EventEmitter<PreviewEvent> for MarkdownPreviewView {}
+impl EventEmitter<()> for MarkdownPreviewView {}
 
 impl Item for MarkdownPreviewView {
-    type Event = PreviewEvent;
+    type Event = ();
 
     fn tab_icon(&self, _window: &Window, _cx: &App) -> Option<Icon> {
         Some(Icon::new(IconName::FileDoc))
     }
 
-    fn tab_content_text(&self, _detail: usize, _cx: &App) -> SharedString {
-        self.tab_content_text
-            .clone()
+    fn tab_content_text(&self, _detail: usize, cx: &App) -> SharedString {
+        self.active_editor
+            .as_ref()
+            .and_then(|editor_state| {
+                let buffer = editor_state.editor.read(cx).buffer().read(cx);
+                let buffer = buffer.as_singleton()?;
+                let file = buffer.read(cx).file()?;
+                let local_file = file.as_local()?;
+                local_file
+                    .abs_path(cx)
+                    .file_name()
+                    .map(|name| format!("Preview {}", name.to_string_lossy()).into())
+            })
             .unwrap_or_else(|| SharedString::from("Markdown Preview"))
     }