Allow icon themes to provide their own file associations (zed-industries#24926)

This PR adds the ability for icon themes to provide their own file
associations.

The old `file_types.json` that was previously used to make these
associations has been removed in favor of storing them on the default
theme.

Icon themes have two new fields on them:

- `file_stems`: A mapping of file stems to icon keys.
- `file_suffixes`: A mapping of file suffixes to icon keys.

These mappings produce icon keys which can then be used in `file_icons`
to associate them to a particular icon:

```json
{
  "file_stems": {
    "Makefile": "make"
  },
  "file_suffixes": {
    "idr": "idris"
  },
  "file_icons": {
    "idris": { "path": "./icons/idris.svg" },
    "make": { "path": "./icons/make.svg" }
  }
}
```

When loading an icon theme, the `file_stems` and `file_icons` fields
will be merged with the ones from the base icon theme, with the values
from the icon theme being loaded overriding ones in the base theme.

Release Notes:

- Added the ability for icon themes to provide their own file
associations.

Author: maxdeviant

CONTRIBUTING.md

@@ -43,10 +43,6 @@ Zed's default icon theme consists of icons that are hand-designed to fit togethe
 
 We do not accept PRs for file icons that are just an off-the-shelf SVG taken from somewhere else.
 
-### File icon associations
-
-We will happily accept PRs that add new file icon associations to [`file_types.json`](assets/icons/file_icons/file_types.json) to allow them to be targeted by [icon themes](https://zed.dev/docs/extensions/icon-themes).
-
 ### Adding new icons to the Zed icon theme
 
 If you would like to add a new icon to the Zed icon theme, [open a Discussion](https://github.com/zed-industries/zed/discussions/new?category=ux-and-design) and we can work with you on getting an icon designed and added to Zed.

Cargo.lock

@@ -13,11 +13,8 @@ path = "src/file_icons.rs"
 doctest = false
 
 [dependencies]
-collections.workspace = true
 gpui.workspace = true
 serde.workspace = true
-serde_derive.workspace = true
-serde_json.workspace = true
 settings.workspace = true
 theme.workspace = true
 util.workspace = true

assets/icons/file_icons/file_types.json

@@ -1,52 +1,33 @@
 use std::sync::Arc;
 use std::{path::Path, str};
 
-use collections::HashMap;
-
-use gpui::{App, AssetSource, Global, SharedString};
-use serde_derive::Deserialize;
+use gpui::{App, SharedString};
 use settings::Settings;
 use theme::{IconTheme, ThemeRegistry, ThemeSettings};
 use util::paths::PathExt;
 
-#[derive(Deserialize, Debug)]
+#[derive(Debug)]
 pub struct FileIcons {
-    stems: HashMap<String, String>,
-    suffixes: HashMap<String, String>,
-}
-
-impl Global for FileIcons {}
-
-pub const FILE_TYPES_ASSET: &str = "icons/file_icons/file_types.json";
-
-pub fn init(assets: impl AssetSource, cx: &mut App) {
-    cx.set_global(FileIcons::new(assets))
+    icon_theme: Arc<IconTheme>,
 }
 
 impl FileIcons {
-    pub fn get(cx: &App) -> &Self {
-        cx.global::<FileIcons>()
-    }
+    pub fn get(cx: &App) -> Self {
+        let theme_settings = ThemeSettings::get_global(cx);
 
-    pub fn new(assets: impl AssetSource) -> Self {
-        assets
-            .load(FILE_TYPES_ASSET)
-            .ok()
-            .flatten()
-            .and_then(|file| serde_json::from_str::<FileIcons>(str::from_utf8(&file).unwrap()).ok())
-            .unwrap_or_else(|| FileIcons {
-                stems: HashMap::default(),
-                suffixes: HashMap::default(),
-            })
+        Self {
+            icon_theme: theme_settings.active_icon_theme.clone(),
+        }
     }
 
     pub fn get_icon(path: &Path, cx: &App) -> Option<SharedString> {
-        let this = cx.try_global::<Self>()?;
+        let this = Self::get(cx);
 
         let get_icon_from_suffix = |suffix: &str| -> Option<SharedString> {
-            this.stems
+            this.icon_theme
+                .file_stems
                 .get(suffix)
-                .or_else(|| this.suffixes.get(suffix))
+                .or_else(|| this.icon_theme.file_suffixes.get(suffix))
                 .and_then(|typ| this.get_icon_for_type(typ, cx))
         };
         // TODO: Associate a type with the languages and have the file's language