134 lines
2.6 KiB
Rust
134 lines
2.6 KiB
Rust
// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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/*!
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The Finally trait provides a method, `finally` on
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stack closures that emulates Java-style try/finally blocks.
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# Example
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~~~
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do || {
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...
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}.finally {
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alway_run_this();
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}
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~~~
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*/
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use ops::Drop;
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#[cfg(test)] use task::{failing, spawn};
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pub trait Finally<T> {
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fn finally(&self, dtor: &fn()) -> T;
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}
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macro_rules! finally_fn {
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($fnty:ty) => {
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impl<T> Finally<T> for $fnty {
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fn finally(&self, dtor: &fn()) -> T {
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let _d = Finallyalizer {
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dtor: dtor
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};
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(*self)()
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}
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}
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}
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}
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impl<'self,T> Finally<T> for &'self fn() -> T {
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fn finally(&self, dtor: &fn()) -> T {
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let _d = Finallyalizer {
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dtor: dtor
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};
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(*self)()
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}
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}
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finally_fn!(~fn() -> T)
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finally_fn!(@fn() -> T)
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finally_fn!(extern "Rust" fn() -> T)
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struct Finallyalizer<'self> {
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dtor: &'self fn()
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}
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#[unsafe_destructor]
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impl<'self> Drop for Finallyalizer<'self> {
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fn drop(&self) {
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(self.dtor)();
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}
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}
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#[test]
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fn test_success() {
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let mut i = 0;
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do (|| {
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i = 10;
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}).finally {
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assert!(!failing());
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assert_eq!(i, 10);
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i = 20;
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}
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assert_eq!(i, 20);
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}
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#[test]
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#[ignore(cfg(windows))]
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#[should_fail]
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fn test_fail() {
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let mut i = 0;
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do (|| {
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i = 10;
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fail!();
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}).finally {
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assert!(failing());
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assert_eq!(i, 10);
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}
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}
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#[test]
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fn test_retval() {
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let closure: &fn() -> int = || 10;
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let i = do closure.finally { };
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assert_eq!(i, 10);
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}
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#[test]
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fn test_compact() {
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fn do_some_fallible_work() {}
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fn but_always_run_this_function() { }
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do_some_fallible_work.finally(
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but_always_run_this_function);
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}
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#[test]
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fn test_owned() {
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fn spawn_with_finalizer(f: ~fn()) {
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do spawn { do f.finally { } }
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}
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let owned: ~fn() = || { };
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spawn_with_finalizer(owned);
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}
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#[test]
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fn test_managed() {
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let i = @mut 10;
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let managed: @fn() -> int = || {
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let r = *i;
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*i += 10;
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r
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};
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assert_eq!(do managed.finally {}, 10);
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assert_eq!(*i, 20);
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}
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