Allow to construct Data instances to avoid double Arc for Send + Sync types.

CHANGES.md

@@ -1,5 +1,10 @@
 # Changes
 
+### Changed
+
+* Allow to construct `Data` instances to avoid double `Arc` for `Send + Sync` types.
+
+
 ## [1.0.0-beta.2] - 2019-04-24
 
 ### Added

src/app.rs

@@ -95,8 +95,8 @@ where
     ///                 web::get().to(index)));
     /// }
     /// ```
-    pub fn data<S: 'static>(mut self, data: S) -> Self {
-        self.data.push(Box::new(Data::new(data)));
+    pub fn data<U: Into<Data<U>> + 'static>(mut self, data: U) -> Self {
+        self.data.push(Box::new(data.into()));
         self
     }
 

src/data.rs

@@ -33,29 +33,33 @@ pub(crate) trait DataFactoryResult {
 /// instance for each thread, thus application data must be constructed
 /// multiple times. If you want to share data between different
 /// threads, a shareable object should be used, e.g. `Send + Sync`. Application
-/// data does not need to be `Send` or `Sync`. Internally `Data` instance
-/// uses `Arc`.
+/// data does not need to be `Send` or `Sync`. Internally `Data` type
+/// uses `Arc`. if your data implements `Send` + `Sync` traits you can
+/// use `web::Data::new()` and avoid double `Arc`.
 ///
 /// If route data is not set for a handler, using `Data<T>` extractor would
 /// cause *Internal Server Error* response.
 ///
 /// ```rust
-/// use std::cell::Cell;
+/// use std::sync::Mutex;
 /// use actix_web::{web, App};
 ///
 /// struct MyData {
-///     counter: Cell<usize>,
+///     counter: usize,
 /// }
 ///
 /// /// Use `Data<T>` extractor to access data in handler.
-/// fn index(data: web::Data<MyData>) {
-///     data.counter.set(data.counter.get() + 1);
+/// fn index(data: web::Data<Mutex<MyData>>) {
+///     let mut data = data.lock().unwrap();
+///     data.counter += 1;
 /// }
 ///
 /// fn main() {
+///     let data = web::Data::new(Mutex::new(MyData{ counter: 0 }));
+///
 ///     let app = App::new()
 ///         // Store `MyData` in application storage.
-///         .data(MyData{ counter: Cell::new(0) })
+///         .data(data.clone())
 ///         .service(
 ///             web::resource("/index.html").route(
 ///                 web::get().to(index)));
@@ -65,7 +69,12 @@ pub(crate) trait DataFactoryResult {
 pub struct Data<T>(Arc<T>);
 
 impl<T> Data<T> {
-    pub(crate) fn new(state: T) -> Data<T> {
+    /// Create new `Data` instance.
+    ///
+    /// Internally `Data` type uses `Arc`. if your data implements
+    /// `Send` + `Sync` traits you can use `web::Data::new()` and
+    /// avoid double `Arc`.
+    pub fn new(state: T) -> Data<T> {
         Data(Arc::new(state))
     }
 
@@ -89,6 +98,12 @@ impl<T> Clone for Data<T> {
     }
 }
 
+impl<T> From<T> for Data<T> {
+    fn from(data: T) -> Self {
+        Data::new(data)
+    }
+}
+
 impl<T: 'static> FromRequest for Data<T> {
     type Config = ();
     type Error = Error;

src/test.rs

@@ -555,7 +555,7 @@ mod tests {
                 web::resource("/index.html")
                     .route(web::put().to(|| HttpResponse::Ok().body("put!")))
                     .route(web::patch().to(|| HttpResponse::Ok().body("patch!")))
-                    .route(web::delete().to(|| HttpResponse::Ok().body("delete!")))
+                    .route(web::delete().to(|| HttpResponse::Ok().body("delete!"))),
             ),
         );
 
@@ -575,9 +575,7 @@ mod tests {
         let result = read_response(&mut app, patch_req);
         assert_eq!(result, Bytes::from_static(b"patch!"));
 
-        let delete_req = TestRequest::delete()
-            .uri("/index.html")
-            .to_request();
+        let delete_req = TestRequest::delete().uri("/index.html").to_request();
         let result = read_response(&mut app, delete_req);
         assert_eq!(result, Bytes::from_static(b"delete!"));
     }