From 579b9008108913c896f4bbe7d35ad7461b427a40 Mon Sep 17 00:00:00 2001
From: Kevin Walter <kevin.walter.private@googlemail.com>
Date: Mon, 22 Sep 2014 02:50:19 +0200
Subject: [PATCH] initial commit

---
 .gitignore  |   3 +
 .travis.yml |  11 +++
 Cargo.toml  |   9 +++
 README.md   |   1 +
 src/lib.rs  | 188 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 212 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 .travis.yml
 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..46bf68e
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+target
+Cargo.lock
+
diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..9952ac1
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,11 @@
+language: rust
+os:
+    - linux
+    - osx
+before_script:
+    - rustc -v
+    - cargo -V
+script:
+    - cargo build -v
+    - cargo test -v
+    - cargo doc -v
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..b399f83
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+
+name = "promise"
+version = "0.0.1"
+authors = ["Kevin Walter <kevin.walter.private@googlemail.com>"]
+
+[lib]
+
+name = "promise"
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..63a7d70
--- /dev/null
+++ b/README.md
@@ -0,0 +1 @@
+# rust-promise [![Build Status](https://travis-ci.org/lucidd/rust-promise.svg?branch=master)](https://travis-ci.org/lucidd/rust-promise)
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..5fd295d
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,188 @@
+extern crate test;
+
+use std::any::Any;
+use std::io::timer;
+use std::time::duration::Duration;
+use std::task::try;
+
+
+pub enum FutureError{
+    TaskFailure(Box<Any+Send>),
+    HungUp
+}
+
+pub struct Promise<T> {
+    sender: Sender<Result<T, FutureError>>
+}
+
+impl<T: Send> Promise<T> {
+
+    fn new(tx: Sender<Result<T, FutureError>>) -> Promise<T>{
+        Promise{ sender: tx }
+    }
+
+    pub fn resolve(self, value: T) {
+        self.sender.send(Ok(value))
+    }
+
+    fn fail(self, error: FutureError) {
+        self.sender.send(Err(error))
+    }
+
+}
+
+pub struct Future<T> {
+    receiver: Receiver<Result<T, FutureError>>
+}
+
+impl<T: Send> Future<T>{
+
+    fn new(rx: Receiver<Result<T, FutureError>>) -> Future<T> {
+        Future{ receiver: rx }
+    }
+
+    pub fn value(val: T) -> Future<T> {
+        let (p, f) = promise::<T>();
+        p.resolve(val);
+        f
+    }
+
+    pub fn from_fn(func: proc(): Send -> T) -> Future<T> {
+        let (p, f) = promise::<T>();
+        spawn(proc() {
+            match try(func) {
+                Ok(val) => p.resolve(val),
+                Err(err) => p.fail(TaskFailure(err)),
+            };
+        });
+        f
+    }
+
+    pub fn delay(func: proc(): Send -> T, duration: Duration) -> Future<T> {
+        Future::from_fn(proc() {
+            timer::sleep(duration);
+            func()
+        })
+    }
+
+    pub fn map<B: Send>(self, func: proc(T): Send -> B) -> Future<B> {
+        let (p ,f) = promise::<B>();
+        self.on_complete(proc(res) {
+            match res {
+                Ok(val) => {
+                    match try(proc() func(val)) {
+                        Ok(mapped) => p.resolve(mapped),
+                        Err(err) => p.fail(TaskFailure(err)),
+                    };
+                },
+                Err(err) => p.fail(err),
+            };
+        });
+        f
+    }
+
+    pub fn get(self) -> Result<T, FutureError> {
+        match self.receiver.recv_opt() {
+            Ok(res) => res,
+            Err(_) => Err(HungUp),
+        }
+    }
+
+    pub fn on_complete(self, f: proc(Result<T, FutureError>):Send) {
+        spawn(proc(){
+            let result = self.get();
+            f(result);
+        });
+    }
+
+}
+
+pub fn promise<T :Send>() -> (Promise<T>, Future<T>) {
+    let (tx, rx) = channel();
+    (Promise::new(tx), Future::new(rx))
+}
+
+
+#[cfg(test)]
+mod tests {
+    use super::{promise, Future, HungUp, TaskFailure};
+    use std::any::AnyRefExt;
+    use std::boxed::BoxAny;
+    use std::time::duration::Duration;
+    use std::io::timer;
+
+
+    #[test]
+    fn test_future(){
+        let (p, f) = promise();
+        p.resolve(123u);
+        assert_eq!(f.get().ok(), Some(123u));
+    }
+
+    #[test]
+    fn test_future2(){
+        let (p, f) = promise::<uint>();
+        spawn(proc(){
+            timer::sleep(Duration::seconds(1));
+            p;
+        });
+        match f.get() {
+            Err(HungUp) => (),
+            _ => fail!("should not happen"),
+        }
+    }
+
+    #[test]
+    fn test_future_from_fn(){
+        let f = Future::from_fn(proc() 123u);
+        assert_eq!(f.get().ok(), Some(123u));
+    }
+
+    #[test]
+    fn test_future_from_fn_fail(){
+        let f = Future::from_fn(proc() {
+            fail!("ooops");
+            123u
+        });
+        let err = match f.get() {
+            Err(TaskFailure(err)) => err,
+            _ => fail!("should not happen"),
+        };
+        assert!(err.is::<&'static str>());
+        assert_eq!(*err.downcast::<&'static str>().unwrap(), "ooops");
+    }
+
+    #[test]
+    fn test_future_delay(){
+        let f = Future::delay(proc() 123u, Duration::seconds(3));
+        //TODO: test delay
+        assert_eq!(f.get().ok(), Some(123u));
+    }
+
+    #[test]
+    fn test_future_value(){
+        let f = Future::value(123u);
+        assert_eq!(f.get().ok(), Some(123u));
+    }
+
+    #[test]
+    fn test_future_on_complete(){
+        let (tx, rx) = channel();
+        let f = Future::delay(proc() 123u, Duration::seconds(3));
+        f.on_complete(proc(x){
+            tx.send(x);
+        });
+        assert_eq!(rx.recv().ok(), Some(123u))
+    }
+
+    #[test]
+    fn test_future_map(){
+        let (tx, rx) = channel();
+        let f = Future::value(3u);
+        f.map(proc(x) x*x).on_complete(proc(x){
+            tx.send(x);
+        });
+        assert_eq!(rx.recv().ok(), Some(9u));
+    }
+
+}