Add a cached fs abstraction

crates/common/src/fs/cached_file_system.rs

@@ -0,0 +1,38 @@
+//! Implements a cached file system that allows for files to be read once into memory and then when
+//! they're requested to be read again they will be returned from the cache.
+
+use std::{
+    collections::HashMap,
+    path::{Path, PathBuf},
+    sync::{Arc, LazyLock},
+};
+
+use anyhow::Result;
+use tokio::sync::RwLock;
+
+#[allow(clippy::type_complexity)]
+static CACHE: LazyLock<Arc<RwLock<HashMap<PathBuf, Vec<u8>>>>> = LazyLock::new(Default::default);
+
+pub struct CachedFileSystem;
+
+impl CachedFileSystem {
+    pub async fn read(path: impl AsRef<Path>) -> Result<Vec<u8>> {
+        let cache_read_lock = CACHE.read().await;
+        match cache_read_lock.get(path.as_ref()) {
+            Some(entry) => Ok(entry.clone()),
+            None => {
+                drop(cache_read_lock);
+
+                let content = std::fs::read(&path)?;
+                let mut cache_write_lock = CACHE.write().await;
+                cache_write_lock.insert(path.as_ref().to_path_buf(), content.clone());
+                Ok(content)
+            }
+        }
+    }
+
+    pub async fn read_to_string(path: impl AsRef<Path>) -> Result<String> {
+        let content = Self::read(path).await?;
+        String::from_utf8(content).map_err(Into::into)
+    }
+}

crates/common/src/fs/mod.rs

@@ -1,3 +1,5 @@
+mod cached_file_system;
 mod clear_dir;
 
+pub use cached_file_system::*;
 pub use clear_dir::*;