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// Copyright (c) 2013-2017 Sandstorm Development Group, Inc. and contributors // // Permission is hereby granted, free of charge, to any person obtaining a copy // of this software and associated documentation files (the "Software"), to deal // in the Software without restriction, including without limitation the rights // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell // copies of the Software, and to permit persons to whom the Software is // furnished to do so, subject to the following conditions: // // The above copyright notice and this permission notice shall be included in // all copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN // THE SOFTWARE. use futures::{Future}; pub struct AttachFuture<F, T> where F: Future { original_future: F, value: Option<T>, } impl <F, T> Future for AttachFuture<F, T> where F: Future, { type Item = F::Item; type Error = F::Error; fn poll(&mut self) -> ::futures::Poll<Self::Item, Self::Error> { let result = self.original_future.poll(); if let Ok(::futures::Async::Ready(_)) = result { self.value.take(); } result } } pub trait Attach: Future { fn attach<T>(self, value: T) -> AttachFuture<Self, T> where Self: Sized { AttachFuture { original_future: self, value: Some(value), } } } impl <F> Attach for F where F: Future {}