feat: image resizing (#5446)

Add image resizing on the client side to reduce load on the API

codex-rs/utils/cache/src/lib.rs

@@ -0,0 +1,159 @@
+use std::borrow::Borrow;
+use std::hash::Hash;
+use std::num::NonZeroUsize;
+
+use lru::LruCache;
+use sha1::Digest;
+use sha1::Sha1;
+use tokio::sync::Mutex;
+use tokio::sync::MutexGuard;
+
+/// A minimal LRU cache protected by a Tokio mutex.
+pub struct BlockingLruCache<K, V> {
+    inner: Mutex<LruCache<K, V>>,
+}
+
+impl<K, V> BlockingLruCache<K, V>
+where
+    K: Eq + Hash,
+{
+    /// Creates a cache with the provided non-zero capacity.
+    #[must_use]
+    pub fn new(capacity: NonZeroUsize) -> Self {
+        Self {
+            inner: Mutex::new(LruCache::new(capacity)),
+        }
+    }
+
+    /// Returns a clone of the cached value for `key`, or computes and inserts it.
+    pub fn get_or_insert_with(&self, key: K, value: impl FnOnce() -> V) -> V
+    where
+        V: Clone,
+    {
+        let mut guard = lock_blocking(&self.inner);
+        if let Some(v) = guard.get(&key) {
+            return v.clone();
+        }
+        let v = value();
+        // Insert and return a clone to keep ownership in the cache.
+        guard.put(key, v.clone());
+        v
+    }
+
+    /// Like `get_or_insert_with`, but the value factory may fail.
+    pub fn get_or_try_insert_with<E>(
+        &self,
+        key: K,
+        value: impl FnOnce() -> Result<V, E>,
+    ) -> Result<V, E>
+    where
+        V: Clone,
+    {
+        let mut guard = lock_blocking(&self.inner);
+        if let Some(v) = guard.get(&key) {
+            return Ok(v.clone());
+        }
+        let v = value()?;
+        guard.put(key, v.clone());
+        Ok(v)
+    }
+
+    /// Builds a cache if `capacity` is non-zero, returning `None` otherwise.
+    #[must_use]
+    pub fn try_with_capacity(capacity: usize) -> Option<Self> {
+        NonZeroUsize::new(capacity).map(Self::new)
+    }
+
+    /// Returns a clone of the cached value corresponding to `key`, if present.
+    pub fn get<Q>(&self, key: &Q) -> Option<V>
+    where
+        K: Borrow<Q>,
+        Q: Hash + Eq + ?Sized,
+        V: Clone,
+    {
+        lock_blocking(&self.inner).get(key).cloned()
+    }
+
+    /// Inserts `value` for `key`, returning the previous entry if it existed.
+    pub fn insert(&self, key: K, value: V) -> Option<V> {
+        lock_blocking(&self.inner).put(key, value)
+    }
+
+    /// Removes the entry for `key` if it exists, returning it.
+    pub fn remove<Q>(&self, key: &Q) -> Option<V>
+    where
+        K: Borrow<Q>,
+        Q: Hash + Eq + ?Sized,
+    {
+        lock_blocking(&self.inner).pop(key)
+    }
+
+    /// Clears all entries from the cache.
+    pub fn clear(&self) {
+        lock_blocking(&self.inner).clear();
+    }
+
+    /// Executes `callback` with a mutable reference to the underlying cache.
+    pub fn with_mut<R>(&self, callback: impl FnOnce(&mut LruCache<K, V>) -> R) -> R {
+        let mut guard = lock_blocking(&self.inner);
+        callback(&mut guard)
+    }
+
+    /// Provides direct access to the cache guard for advanced use cases.
+    pub fn blocking_lock(&self) -> MutexGuard<'_, LruCache<K, V>> {
+        lock_blocking(&self.inner)
+    }
+}
+
+fn lock_blocking<K, V>(m: &Mutex<LruCache<K, V>>) -> MutexGuard<'_, LruCache<K, V>>
+where
+    K: Eq + Hash,
+{
+    match tokio::runtime::Handle::try_current() {
+        Ok(_) => tokio::task::block_in_place(|| m.blocking_lock()),
+        Err(_) => m.blocking_lock(),
+    }
+}
+
+/// Computes the SHA-1 digest of `bytes`.
+///
+/// Useful for content-based cache keys when you want to avoid staleness
+/// caused by path-only keys.
+#[must_use]
+pub fn sha1_digest(bytes: &[u8]) -> [u8; 20] {
+    let mut hasher = Sha1::new();
+    hasher.update(bytes);
+    let result = hasher.finalize();
+    let mut out = [0; 20];
+    out.copy_from_slice(&result);
+    out
+}
+
+#[cfg(test)]
+mod tests {
+    use super::BlockingLruCache;
+    use std::num::NonZeroUsize;
+
+    #[tokio::test(flavor = "multi_thread")]
+    async fn stores_and_retrieves_values() {
+        let cache = BlockingLruCache::new(NonZeroUsize::new(2).expect("capacity"));
+
+        assert!(cache.get(&"first").is_none());
+        cache.insert("first", 1);
+        assert_eq!(cache.get(&"first"), Some(1));
+    }
+
+    #[tokio::test(flavor = "multi_thread")]
+    async fn evicts_least_recently_used() {
+        let cache = BlockingLruCache::new(NonZeroUsize::new(2).expect("capacity"));
+        cache.insert("a", 1);
+        cache.insert("b", 2);
+        assert_eq!(cache.get(&"a"), Some(1));
+
+        cache.insert("c", 3);
+
+        assert!(cache.get(&"b").is_none());
+        assert_eq!(cache.get(&"a"), Some(1));
+        assert_eq!(cache.get(&"c"), Some(3));
+    }
+}