From fbad62cf9e3688b7d7215ebbff6669c5bed4f572 Mon Sep 17 00:00:00 2001
From: Emulator000 <emulator@hotmail.it>
Date: Fri, 25 Sep 2020 18:31:13 +0200
Subject: [PATCH] First version of the library

---
 .gitignore |   3 ++
 Cargo.toml |  14 ++++++
 README.md  |  23 ++++++++++
 src/lib.rs | 129 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 169 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 Cargo.toml
 create mode 100644 README.md
 create mode 100644 src/lib.rs

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..b471067
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+/target
+Cargo.lock
+.idea
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..f350b13
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,14 @@
+[package]
+    name = "simple-cache"
+    description = "A basic and simple Rust library async/await ready caching implementation for structures."
+    version = "0.1.0"
+    authors = ["Emulator000 <emulator@hotmail.it>"]
+    edition = "2018"
+    readme = "README.md"
+    repository = "https://github.com/Emulator000/simple-cache"
+    license = "MIT"
+
+[dependencies]
+    async-std = "^1.6"
+    arc-swap = "^0.4"
+    tokio = { version = "^0.2", features = ["full"] }
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..8bcf22f
--- /dev/null
+++ b/README.md
@@ -0,0 +1,23 @@
+# Simple Cache
+A basic and simple Rust library async/await ready caching implementation for structures.
+
+## Usage
+```rust
+use simple_cache::Cache;
+
+fn main() {
+    let cache = Cache::new();
+    let object = Object {
+        value: 1,
+        string: String::from("test!"),
+    };
+
+    cache.insert("test", Some(object)).await;
+
+    let cached_object = cache.get::<Object, _>("test").await.unwrap().unwrap();
+    
+    if cached_object.value == 1 {
+        println!("Hi from Simple Cache!");
+    }
+}
+```
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..8dbc317
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,129 @@
+use std::any::Any;
+use std::borrow::Borrow;
+use std::collections::HashMap;
+use std::hash::Hash;
+use std::sync::Arc;
+
+use async_std::sync::RwLock;
+
+use arc_swap::ArcSwap;
+
+type AnyObject = Box<dyn Any + Send + Sync>;
+type CacheObject = Option<ArcSwap<AnyObject>>;
+
+pub trait CacheItem: Send + Sync {}
+
+pub enum CacheResult {
+    Ok,
+    Error,
+}
+
+#[derive(Clone)]
+pub struct Cache<K> {
+    items: Arc<RwLock<HashMap<K, CacheObject>>>,
+}
+
+impl<K> Cache<K>
+where
+    K: Eq + Hash,
+{
+    pub fn new() -> Self {
+        Self {
+            items: Arc::new(RwLock::new(HashMap::new())),
+        }
+    }
+
+    pub async fn get<T: 'static + CacheItem, Q: ?Sized>(&self, key: &Q) -> Option<Option<Arc<T>>>
+    where
+        K: Borrow<Q>,
+        Q: Hash + Eq,
+    {
+        match self.items.read().await.get(key) {
+            Some(object) => match object {
+                Some(object) => Some(match object.load().downcast_ref::<Arc<T>>() {
+                    Some(value) => Some(value.to_owned()),
+                    None => None,
+                }),
+                None => Some(None),
+            },
+            None => None,
+        }
+    }
+
+    pub async fn insert<T: 'static + CacheItem>(&self, key: K, value: Option<T>) -> CacheResult {
+        match self.items.write().await.insert(
+            key,
+            match value {
+                Some(value) => Some(ArcSwap::new(Arc::new(
+                    Box::new(Arc::new(value)) as AnyObject
+                ))),
+                None => None,
+            },
+        ) {
+            Some(_) => CacheResult::Ok,
+            None => CacheResult::Error,
+        }
+    }
+
+    pub async fn remove<Q: ?Sized>(&self, key: &Q) -> CacheResult
+    where
+        K: Borrow<Q>,
+        Q: Hash + Eq,
+    {
+        match self.items.write().await.remove(key) {
+            Some(_) => CacheResult::Ok,
+            None => CacheResult::Error,
+        }
+    }
+}
+
+impl<K> Default for Cache<K>
+where
+    K: Eq + Hash,
+{
+    fn default() -> Self {
+        Cache::new()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::{Cache, CacheItem};
+
+    struct Object {
+        value: i32,
+        string: String,
+    }
+
+    impl CacheItem for Object {}
+
+    #[tokio::test]
+    async fn insert_and_get() {
+        let cache = Cache::new();
+        let object = Object {
+            value: 1,
+            string: String::from("test!"),
+        };
+
+        cache.insert("test", Some(object)).await;
+
+        let cached_object = cache.get::<Object, _>("test").await.unwrap().unwrap();
+
+        assert_eq!(cached_object.value, 1);
+        assert_eq!(cached_object.string, "test!");
+    }
+
+    #[tokio::test]
+    async fn remove() {
+        let cache = Cache::new();
+        let object = Object {
+            value: 1,
+            string: String::from("test!"),
+        };
+
+        cache.insert("test", Some(object)).await;
+        cache.remove("test").await;
+
+        assert_eq!(cache.get::<Object, _>("test").await.is_none(), true);
+    }
+}