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//! Defines types for passing request state through `Middleware` and `Handler` implementations mod data; mod from_state; pub mod request_id; use std::collections::HashMap; use std::any::{Any, TypeId}; pub use state::data::StateData; pub use state::from_state::FromState; pub use state::request_id::request_id; pub use state::request_id::set_request_id; /// Provides storage for request state, and stores one item of each type. The types used for /// storage must implement the `gotham::state::StateData` trait to allow its storage. /// /// Gotham provides `StateData` to ease this implementation via `derive`. /// /// # Examples /// /// ```rust /// extern crate gotham; /// #[macro_use] /// extern crate gotham_derive; /// /// use gotham::state::State; /// /// #[derive(StateData)] /// struct MyStruct { /// value: i32 /// } /// /// # fn main() { /// let mut state = State::new(); /// /// state.put(MyStruct { value: 1 }); /// assert_eq!(state.borrow::<MyStruct>().unwrap().value, 1); /// # } /// ``` pub struct State { data: HashMap<TypeId, Box<Any + Send>>, } impl State { /// Creates a new, empty `State` pub fn new() -> State { State { data: HashMap::new() } } /// Puts a value into the `State` storage. One value of each type is retained. Successive calls /// to `put` will overwrite the existing value of the same type. /// /// # Examples /// /// ```rust /// # extern crate gotham; /// # #[macro_use] /// # extern crate gotham_derive; /// # /// # use gotham::state::State; /// # /// # #[derive(StateData)] /// # struct MyStruct { /// # value: i32 /// # } /// # /// # #[derive(StateData)] /// # struct AnotherStruct { /// # value: &'static str /// # } /// # /// # fn main() { /// # let mut state = State::new(); /// # /// state.put(MyStruct { value: 1 }); /// assert_eq!(state.borrow::<MyStruct>().unwrap().value, 1); /// /// state.put(AnotherStruct { value: "a string" }); /// state.put(MyStruct { value: 100 }); /// /// assert_eq!(state.borrow::<AnotherStruct>().unwrap().value, "a string"); /// assert_eq!(state.borrow::<MyStruct>().unwrap().value, 100); /// # } /// ``` pub fn put<T>(&mut self, t: T) where T: StateData, { let type_id = TypeId::of::<T>(); trace!(" inserting record to state for type_id `{:?}`", type_id); self.data.insert(type_id, Box::new(t)); } /// Determines if the current value exists in `State` storage. /// /// # Examples /// /// ```rust /// # extern crate gotham; /// # #[macro_use] /// # extern crate gotham_derive; /// # /// # use gotham::state::State; /// # /// # #[derive(StateData)] /// # struct MyStruct { /// # value: i32 /// # } /// # /// # #[derive(StateData)] /// # struct AnotherStruct { /// # } /// # /// # fn main() { /// # let mut state = State::new(); /// # /// state.put(MyStruct { value: 1 }); /// assert!(state.has::<MyStruct>()); /// assert_eq!(state.borrow::<MyStruct>().unwrap().value, 1); /// /// assert!(!state.has::<AnotherStruct>()); /// # } /// ``` pub fn has<T>(&self) -> bool where T: StateData, { let type_id = TypeId::of::<T>(); self.data.get(&type_id).is_some() } /// Borrows a value from the `State` storage. /// /// # Examples /// /// ```rust /// # extern crate gotham; /// # #[macro_use] /// # extern crate gotham_derive; /// # /// # use gotham::state::State; /// # /// # #[derive(StateData)] /// # struct MyStruct { /// # value: i32 /// # } /// # /// # #[derive(StateData)] /// # struct AnotherStruct { /// # } /// # /// # fn main() { /// # let mut state = State::new(); /// # /// state.put(MyStruct { value: 1 }); /// assert!(state.borrow::<MyStruct>().is_some()); /// assert_eq!(state.borrow::<MyStruct>().unwrap().value, 1); /// /// assert!(state.borrow::<AnotherStruct>().is_none()); /// # } /// ``` pub fn borrow<T>(&self) -> Option<&T> where T: StateData, { let type_id = TypeId::of::<T>(); trace!(" borrowing state data for type_id `{:?}`", type_id); self.data.get(&type_id).and_then(|b| b.downcast_ref::<T>()) } /// Mutably borrows a value from the `State` storage. /// /// # Examples /// /// ```rust /// # extern crate gotham; /// # #[macro_use] /// # extern crate gotham_derive; /// # /// # use gotham::state::State; /// # /// # #[derive(StateData)] /// # struct MyStruct { /// # value: i32 /// # } /// # /// # #[derive(StateData)] /// # struct AnotherStruct { /// # } /// # /// # fn main() { /// # let mut state = State::new(); /// # /// state.put(MyStruct { value: 100 }); /// /// { /// let a = state.borrow_mut::<MyStruct>().unwrap(); /// a.value += 10; /// } /// /// assert_eq!(state.borrow::<MyStruct>().unwrap().value, 110); /// /// assert!(state.borrow_mut::<AnotherStruct>().is_none()); /// # } pub fn borrow_mut<T>(&mut self) -> Option<&mut T> where T: StateData, { let type_id = TypeId::of::<T>(); trace!(" mutably borrowing state data for type_id `{:?}`", type_id); self.data.get_mut(&type_id).and_then( |b| b.downcast_mut::<T>(), ) } /// Moves a value out of the `State` storage, and returns ownership. /// /// # Examples /// /// ```rust /// # extern crate gotham; /// # #[macro_use] /// # extern crate gotham_derive; /// # /// # use gotham::state::State; /// # /// # #[derive(StateData)] /// # struct MyStruct { /// # value: i32 /// # } /// # /// # #[derive(StateData)] /// # struct AnotherStruct { /// # } /// # /// # fn main() { /// # let mut state = State::new(); /// # /// state.put(MyStruct { value: 110 }); /// /// assert_eq!(state.take::<MyStruct>().unwrap().value, 110); /// /// assert!(state.take::<MyStruct>().is_none()); /// assert!(state.borrow_mut::<MyStruct>().is_none()); /// assert!(state.borrow::<MyStruct>().is_none()); /// /// assert!(state.take::<AnotherStruct>().is_none()); /// # } pub fn take<T>(&mut self) -> Option<T> where T: StateData, { let type_id = TypeId::of::<T>(); trace!( " taking ownership from state data for type_id `{:?}`", type_id ); self.data .remove(&type_id) .and_then(|b| b.downcast::<T>().ok()) .map(|b| *b) } }