Implement SVG rendering

gpui/src/assets.rs

@@ -1,5 +1,5 @@
 use anyhow::{anyhow, Result};
-use std::borrow::Cow;
+use std::{borrow::Cow, cell::RefCell, collections::HashMap};
 
 pub trait AssetSource: 'static {
     fn load(&self, path: &str) -> Result<Cow<[u8]>>;
@@ -16,12 +16,26 @@ impl AssetSource for () {
 
 pub struct AssetCache {
     source: Box<dyn AssetSource>,
+    svgs: RefCell<HashMap<String, usvg::Tree>>,
 }
 
 impl AssetCache {
     pub fn new(source: impl AssetSource) -> Self {
         Self {
             source: Box::new(source),
+            svgs: RefCell::new(HashMap::new()),
+        }
+    }
+
+    pub fn svg(&self, path: &str) -> Result<usvg::Tree> {
+        let mut svgs = self.svgs.borrow_mut();
+        if let Some(svg) = svgs.get(path) {
+            Ok(svg.clone())
+        } else {
+            let bytes = self.source.load(path)?;
+            let svg = usvg::Tree::from_data(&bytes, &usvg::Options::default())?;
+            svgs.insert(path.to_string(), svg.clone());
+            Ok(svg)
         }
     }
 }