Introduce an outline panel (zed-industries#12637)

Adds a new panel: `OutlinePanel` which looks very close to project
panel:

<img width="256" alt="Screenshot 2024-06-10 at 23 19 05"
src="https://github.com/zed-industries/zed/assets/2690773/c66e6e78-44ec-4de8-8d60-43238bb09ae9">

has similar settings and keymap (actions work in the `OutlinePanel`
context and are under `outline_panel::` namespace), with two notable
differences:
* no "edit" actions such as cut/copy/paste/delete/etc.
* directory auto folding is enabled by default

Empty view: 
<img width="841" alt="Screenshot 2024-06-10 at 23 19 11"
src="https://github.com/zed-industries/zed/assets/2690773/dc8bf37c-5a70-4fd5-9b57-76271eb7a40c">


When editor gets active, the panel displays all related files in a tree
(similar to what the project panel does) and all related excerpts'
outlines under each file.
Same as in the project panel, directories can be expanded or collapsed,
unfolded or folded; clicking file entries or outlines scrolls the buffer
to the corresponding excerpt; changing editor's selection reveals the
corresponding outline in the panel.

The panel is applicable to any singleton buffer:
<img width="1215" alt="Screenshot 2024-06-10 at 23 19 35"
src="https://github.com/zed-industries/zed/assets/2690773/a087631f-5c2d-4d4d-ae25-30ab9731d528">

<img width="1728" alt="image"
src="https://github.com/zed-industries/zed/assets/2690773/e4f8082c-d12d-4473-8500-e8fd1051285b">

or any multi buffer:

(search multi buffer)

<img width="1728" alt="Screenshot 2024-06-10 at 23 19 41"
src="https://github.com/zed-industries/zed/assets/2690773/60f768a3-6716-4520-9b13-42da8fd15f50">

(diagnostics multi buffer)
<img width="1728" alt="image"
src="https://github.com/zed-industries/zed/assets/2690773/64e285bd-9530-4bf2-8f1f-10ee5596067c">

Release Notes:
- Added an outline panel to show a "map" of the active editor

Cargo.toml

@@ -64,6 +64,7 @@ members = [
     "crates/ollama",
     "crates/open_ai",
     "crates/outline",
+    "crates/outline_panel",
     "crates/picker",
     "crates/prettier",
     "crates/project",
@@ -212,6 +213,7 @@ notifications = { path = "crates/notifications" }
 ollama = { path = "crates/ollama" }
 open_ai = { path = "crates/open_ai" }
 outline = { path = "crates/outline" }
+outline_panel = { path = "crates/outline_panel" }
 picker = { path = "crates/picker" }
 plugin = { path = "crates/plugin" }
 plugin_macros = { path = "crates/plugin_macros" }

assets/keymaps/default-linux.json

@@ -439,6 +439,7 @@
       "ctrl-shift-p": "command_palette::Toggle",
       "ctrl-shift-m": "diagnostics::Deploy",
       "ctrl-shift-e": "project_panel::ToggleFocus",
+      "ctrl-shift-b": "outline_panel::ToggleFocus",
       "ctrl-?": "assistant::ToggleFocus",
       "ctrl-alt-s": "workspace::SaveAll",
       "ctrl-k m": "language_selector::Toggle",
@@ -562,6 +563,18 @@
       "ctrl-enter": "project_search::SearchInNew"
     }
   },
+  {
+    "context": "OutlinePanel",
+    "bindings": {
+      "left": "project_panel::CollapseSelectedEntry",
+      "right": "project_panel::ExpandSelectedEntry",
+      "ctrl-alt-c": "project_panel::CopyPath",
+      "alt-ctrl-shift-c": "project_panel::CopyRelativePath",
+      "alt-ctrl-r": "project_panel::RevealInFinder",
+      "shift-down": "menu::SelectNext",
+      "shift-up": "menu::SelectPrev"
+    }
+  },
   {
     "context": "ProjectPanel",
     "bindings": {
@@ -583,7 +596,10 @@
       "ctrl-backspace": ["project_panel::Delete", { "skip_prompt": false }],
       "ctrl-delete": ["project_panel::Delete", { "skip_prompt": false }],
       "alt-ctrl-r": "project_panel::RevealInFinder",
-      "alt-shift-f": "project_panel::NewSearchInDirectory"
+      "alt-shift-f": "project_panel::NewSearchInDirectory",
+      "shift-down": "menu::SelectNext",
+      "shift-up": "menu::SelectPrev",
+      "escape": "menu::Cancel"
     }
   },
   {

assets/keymaps/default-macos.json

@@ -475,6 +475,7 @@
       "cmd-shift-p": "command_palette::Toggle",
       "cmd-shift-m": "diagnostics::Deploy",
       "cmd-shift-e": "project_panel::ToggleFocus",
+      "cmd-shift-b": "outline_panel::ToggleFocus",
       "cmd-?": "assistant::ToggleFocus",
       "cmd-alt-s": "workspace::SaveAll",
       "cmd-k m": "language_selector::Toggle",
@@ -584,6 +585,18 @@
       "cmd-enter": "project_search::SearchInNew"
     }
   },
+  {
+    "context": "OutlinePanel",
+    "bindings": {
+      "left": "outline_panel::CollapseSelectedEntry",
+      "right": "outline_panel::ExpandSelectedEntry",
+      "cmd-alt-c": "outline_panel::CopyPath",
+      "alt-cmd-shift-c": "outline_panel::CopyRelativePath",
+      "alt-cmd-r": "outline_panel::RevealInFinder",
+      "shift-down": "menu::SelectNext",
+      "shift-up": "menu::SelectPrev"
+    }
+  },
   {
     "context": "ProjectPanel",
     "bindings": {

assets/settings/default.json

@@ -302,6 +302,29 @@
     /// when a directory has only one directory inside.
     "auto_fold_dirs": false
   },
+  "outline_panel": {
+    // Whether to show the outline panel button in the status bar
+    "button": true,
+    // Default width of the outline panel.
+    "default_width": 240,
+    // Where to dock the outline panel. Can be 'left' or 'right'.
+    "dock": "left",
+    // Whether to show file icons in the outline panel.
+    "file_icons": true,
+    // Whether to show folder icons or chevrons for directories in the outline panel.
+    "folder_icons": true,
+    // Whether to show the git status in the outline panel.
+    "git_status": true,
+    // Amount of indentation for nested items.
+    "indent_size": 20,
+    // Whether to reveal it in the outline panel automatically,
+    // when a corresponding outline entry becomes active.
+    // Gitignored entries are never auto revealed.
+    "auto_reveal_entries": true,
+    /// Whether to fold directories automatically
+    /// when a directory has only one directory inside.
+    "auto_fold_dirs": true
+  },
   "collaboration_panel": {
     // Whether to show the collaboration panel button in the status bar.
     "button": true,

crates/editor/src/editor.rs

@@ -149,6 +149,9 @@ use workspace::{OpenInTerminal, OpenTerminal, TabBarSettings, Toast};
 
 use crate::hover_links::find_url;
 
+pub const FILE_HEADER_HEIGHT: u8 = 1;
+pub const MULTI_BUFFER_EXCERPT_HEADER_HEIGHT: u8 = 1;
+pub const MULTI_BUFFER_EXCERPT_FOOTER_HEIGHT: u8 = 1;
 pub const DEFAULT_MULTIBUFFER_CONTEXT: u32 = 2;
 const CURSOR_BLINK_INTERVAL: Duration = Duration::from_millis(500);
 const MAX_LINE_LEN: usize = 1024;
@@ -529,6 +532,7 @@ pub struct Editor {
     tasks: BTreeMap<(BufferId, BufferRow), RunnableTasks>,
     tasks_update_task: Option<Task<()>>,
     previous_search_ranges: Option<Arc<[Range<Anchor>]>>,
+    file_header_size: u8,
 }
 
 #[derive(Clone)]
@@ -1651,18 +1655,17 @@ impl Editor {
             }),
             merge_adjacent: true,
         };
+        let file_header_size = if show_excerpt_controls { 3 } else { 2 };
         let display_map = cx.new_model(|cx| {
-            let file_header_size = if show_excerpt_controls { 3 } else { 2 };
-
             DisplayMap::new(
                 buffer.clone(),
                 style.font(),
                 font_size,
                 None,
                 show_excerpt_controls,
                 file_header_size,
-                1,
-                1,
+                MULTI_BUFFER_EXCERPT_HEADER_HEIGHT,
+                MULTI_BUFFER_EXCERPT_FOOTER_HEIGHT,
                 fold_placeholder,
                 cx,
             )
@@ -1812,6 +1815,7 @@ impl Editor {
             git_blame_inline_enabled: ProjectSettings::get_global(cx).git.inline_blame_enabled(),
             blame: None,
             blame_subscription: None,
+            file_header_size,
             tasks: Default::default(),
             _subscriptions: vec![
                 cx.observe(&buffer, Self::on_buffer_changed),
@@ -10829,6 +10833,12 @@ impl Editor {
                 self.refresh_inlay_hints(InlayHintRefreshReason::ExcerptsRemoved(ids.clone()), cx);
                 cx.emit(EditorEvent::ExcerptsRemoved { ids: ids.clone() })
             }
+            multi_buffer::Event::ExcerptsEdited { ids } => {
+                cx.emit(EditorEvent::ExcerptsEdited { ids: ids.clone() })
+            }
+            multi_buffer::Event::ExcerptsExpanded { ids } => {
+                cx.emit(EditorEvent::ExcerptsExpanded { ids: ids.clone() })
+            }
             multi_buffer::Event::Reparsed => {
                 self.tasks_update_task = Some(self.refresh_runnables(cx));
 
@@ -11299,6 +11309,10 @@ impl Editor {
         }));
         self
     }
+
+    pub fn file_header_size(&self) -> u8 {
+        self.file_header_size
+    }
 }
 
 fn hunks_for_selections(
@@ -11743,6 +11757,12 @@ pub enum EditorEvent {
     ExcerptsRemoved {
         ids: Vec<ExcerptId>,
     },
+    ExcerptsEdited {
+        ids: Vec<ExcerptId>,
+    },
+    ExcerptsExpanded {
+        ids: Vec<ExcerptId>,
+    },
     BufferEdited,
     Edited,
     Reparsed,

crates/fuzzy/src/char_bag.rs

@@ -1,6 +1,6 @@
 use std::iter::FromIterator;
 
-#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
+#[derive(Copy, Clone, Debug, Default, PartialEq, Eq, Hash)]
 pub struct CharBag(u64);
 
 impl CharBag {

crates/git/src/repository.rs

@@ -316,7 +316,7 @@ fn check_path_to_repo_path_errors(relative_file_path: &Path) -> Result<()> {
     }
 }
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
 pub enum GitFileStatus {
     Added,
     Modified,

crates/gpui/src/color.rs

@@ -1,6 +1,9 @@
 use anyhow::{bail, Context};
 use serde::de::{self, Deserialize, Deserializer, Visitor};
-use std::fmt;
+use std::{
+    fmt,
+    hash::{Hash, Hasher},
+};
 
 /// Convert an RGB hex color code number to a color type
 pub fn rgb(hex: u32) -> Rgba {
@@ -267,6 +270,15 @@ impl Ord for Hsla {
 
 impl Eq for Hsla {}
 
+impl Hash for Hsla {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        state.write_u32(u32::from_be_bytes(self.h.to_be_bytes()));
+        state.write_u32(u32::from_be_bytes(self.s.to_be_bytes()));
+        state.write_u32(u32::from_be_bytes(self.l.to_be_bytes()));
+        state.write_u32(u32::from_be_bytes(self.a.to_be_bytes()));
+    }
+}
+
 /// Construct an [`Hsla`] object from plain values
 pub fn hsla(h: f32, s: f32, l: f32, a: f32) -> Hsla {
     Hsla {

crates/gpui/src/style.rs

@@ -1,4 +1,8 @@
-use std::{iter, mem, ops::Range};
+use std::{
+    hash::{Hash, Hasher},
+    iter, mem,
+    ops::Range,
+};
 
 use crate::{
     black, phi, point, quad, rems, AbsoluteLength, Bounds, ContentMask, Corners, CornersRefinement,
@@ -319,6 +323,20 @@ pub struct HighlightStyle {
 
 impl Eq for HighlightStyle {}
 
+impl Hash for HighlightStyle {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.color.hash(state);
+        self.font_weight.hash(state);
+        self.font_style.hash(state);
+        self.background_color.hash(state);
+        self.underline.hash(state);
+        self.strikethrough.hash(state);
+        state.write_u32(u32::from_be_bytes(
+            self.fade_out.map(|f| f.to_be_bytes()).unwrap_or_default(),
+        ));
+    }
+}
+
 impl Style {
     /// Returns true if the style is visible and the background is opaque.
     pub fn has_opaque_background(&self) -> bool {
@@ -549,7 +567,7 @@ impl Default for Style {
 }
 
 /// The properties that can be applied to an underline.
-#[derive(Refineable, Copy, Clone, Default, Debug, PartialEq, Eq)]
+#[derive(Refineable, Copy, Clone, Default, Debug, PartialEq, Eq, Hash)]
 #[refineable(Debug)]
 pub struct UnderlineStyle {
     /// The thickness of the underline.
@@ -563,7 +581,7 @@ pub struct UnderlineStyle {
 }
 
 /// The properties that can be applied to a strikethrough.
-#[derive(Refineable, Copy, Clone, Default, Debug, PartialEq, Eq)]
+#[derive(Refineable, Copy, Clone, Default, Debug, PartialEq, Eq, Hash)]
 #[refineable(Debug)]
 pub struct StrikethroughStyle {
     /// The thickness of the strikethrough.

crates/language/src/buffer.rs

@@ -2738,12 +2738,13 @@ impl BufferSnapshot {
         Some(items)
     }
 
-    fn outline_items_containing(
+    pub fn outline_items_containing<T: ToOffset>(
         &self,
-        range: Range<usize>,
+        range: Range<T>,
         include_extra_context: bool,
         theme: Option<&SyntaxTheme>,
     ) -> Option<Vec<OutlineItem<Anchor>>> {
+        let range = range.to_offset(self);
         let mut matches = self.syntax.matches(range.clone(), &self.text, |grammar| {
             grammar.outline_config.as_ref().map(|c| &c.query)
         });

crates/language/src/language.rs

@@ -70,7 +70,7 @@ pub use language_registry::{
     PendingLanguageServer, QUERY_FILENAME_PREFIXES,
 };
 pub use lsp::LanguageServerId;
-pub use outline::{Outline, OutlineItem};
+pub use outline::{render_item, Outline, OutlineItem};
 pub use syntax_map::{OwnedSyntaxLayer, SyntaxLayer};
 pub use text::{AnchorRangeExt, LineEnding};
 pub use tree_sitter::{Node, Parser, Tree, TreeCursor};