---

yaml
---
r: 153987
b: refs/heads/try2
c: 51ff6c0
h: refs/heads/master
i:
  153985: 1c5464d
  153983: 096415e
v: v3

Author: bors

[refs]

@@ -5,7 +5,7 @@ refs/heads/snap-stage3: 78a7676898d9f80ab540c6df5d4c9ce35bb50463
 refs/heads/try: 519addf6277dbafccbb4159db4b710c37eaa2ec5
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
-refs/heads/try2: ff3d902fcbcdddc885e03ffe3f84bc9dcb003cec
+refs/heads/try2: 51ff6c075a61cb8219a1d6ce935ccb4cefc7a9fd
 refs/heads/dist-snap: ba4081a5a8573875fed17545846f6f6902c8ba8d
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503

branches/try2/mk/crates.mk

@@ -51,7 +51,7 @@
 
 TARGET_CRATES := libc std green rustuv native flate arena glob term semver \
                  uuid serialize sync getopts collections num test time rand \
-                 url log regex graphviz core rlibc alloc debug rustrt \
+                 url log regex graphviz core rbml rlibc alloc debug rustrt \
                  unicode
 HOST_CRATES := syntax rustc rustdoc fourcc hexfloat regex_macros fmt_macros \
 	       rustc_llvm rustc_back
@@ -71,7 +71,7 @@ DEPS_green := std native:context_switch
 DEPS_rustuv := std native:uv native:uv_support
 DEPS_native := std
 DEPS_syntax := std term serialize log fmt_macros debug
-DEPS_rustc := syntax flate arena serialize getopts \
+DEPS_rustc := syntax flate arena serialize getopts rbml \
               time log graphviz debug rustc_llvm rustc_back
 DEPS_rustc_llvm := native:rustllvm libc std
 DEPS_rustc_back := std syntax rustc_llvm flate log libc
@@ -82,6 +82,7 @@ DEPS_arena := std
 DEPS_graphviz := std
 DEPS_glob := std
 DEPS_serialize := std log
+DEPS_rbml := std log serialize
 DEPS_term := std log
 DEPS_semver := std
 DEPS_uuid := std serialize
@@ -91,7 +92,7 @@ DEPS_collections := core alloc unicode
 DEPS_fourcc := rustc syntax std
 DEPS_hexfloat := rustc syntax std
 DEPS_num := std
-DEPS_test := std getopts serialize term time regex native:rust_test_helpers
+DEPS_test := std getopts serialize rbml term time regex native:rust_test_helpers
 DEPS_time := std serialize
 DEPS_rand := core
 DEPS_url := std

branches/try2/src/doc/complement-lang-faq.md

@@ -1,6 +1,5 @@
 % Language FAQ
 
-
 ## Are there any big programs written in it yet? I want to read big samples.
 
 There aren't many large programs yet. The Rust [compiler][rustc], 60,000+ lines at the time of writing, is written in Rust. As the oldest body of Rust code it has gone through many iterations of the language, and some parts are nicer to look at than others. It may not be the best code to learn from, but [borrowck] and [resolve] were written recently.
@@ -29,6 +28,18 @@ You may also be interested in browsing [GitHub's Rust][github-rust] page.
 
 [github-rust]: https://github.com/trending?l=rust
 
+## Is anyone using Rust in production?
+
+Currently, Rust is still pre-1.0, and so we don't recommend that you use Rust
+in production unless you know exactly what you're getting into.
+
+That said, there are two production deployments of Rust that we're aware of:
+
+* [OpenDNS](http://labs.opendns.com/2013/10/04/zeromq-helping-us-block-malicious-domains/)
+* [Skylight](http://skylight.io)
+
+Let the fact that this is an easily countable number be a warning.
+
 ## Does it run on Windows?
 
 Yes. All development happens in lock-step on all 3 target platforms. Using MinGW, not Cygwin. Note that the windows implementation currently has some limitations: in particular 64-bit build is [not fully supported yet][win64], and all executables created by rustc [depend on libgcc DLL at runtime][libgcc].

branches/try2/src/doc/guide-lifetimes.md

@@ -431,36 +431,6 @@ In any case, whatever the lifetime of `r` is, the pointer produced by
 field of a struct is valid as long as the struct is valid. Therefore,
 the compiler accepts the function `get_x()`.
 
-To emphasize this point, let’s look at a variation on the example, this
-time one that does not compile:
-
-~~~ {.ignore}
-struct Point {x: f64, y: f64}
-fn get_x_sh(p: &Point) -> &f64 {
-    &p.x // Error reported here
-}
-~~~
-
-Here, the function `get_x_sh()` takes a reference as input and
-returns a reference. As before, the lifetime of the reference
-that will be returned is a parameter (specified by the
-caller). That means that `get_x_sh()` promises to return a reference
-that is valid for as long as the caller would like: this is
-subtly different from the first example, which promised to return a
-pointer that was valid for as long as its pointer argument was valid.
-
-Within `get_x_sh()`, we see the expression `&p.x` which takes the
-address of a field of a Point. The presence of this expression
-implies that the compiler must guarantee that , so long as the
-resulting pointer is valid, the original Point won't be moved or changed.
-
-But recall that `get_x_sh()` also promised to
-return a pointer that was valid for as long as the caller wanted it to
-be. Clearly, `get_x_sh()` is not in a position to make both of these
-guarantees; in fact, it cannot guarantee that the pointer will remain
-valid at all once it returns, as the parameter `p` may or may not be
-live in the caller. Therefore, the compiler will report an error here.
-
 In general, if you borrow a struct or box to create a
 reference, it will only be valid within the function
 and cannot be returned. This is why the typical way to return references

branches/try2/src/doc/guide-pointers.md

@@ -578,12 +578,12 @@ fn main() {
 
 Notice we changed the signature of `add_one()` to request a mutable reference.
 
-# Best practices
+## Best practices
 
 Boxes are appropriate to use in two situations: Recursive data structures,
 and occasionally, when returning data.
 
-## Recursive data structures
+### Recursive data structures
 
 Sometimes, you need a recursive data structure. The simplest is known as a
 'cons list':
@@ -615,7 +615,7 @@ we don't know the size, and therefore, we need to heap allocate our list.
 Working with recursive or other unknown-sized data structures is the primary
 use-case for boxes.
 
-## Returning data
+### Returning data
 
 This is important enough to have its own section entirely. The TL;DR is this:
 you don't generally want to return pointers, even when you might in a language
@@ -733,18 +733,15 @@ This part is coming soon.
 
 Here's a quick rundown of Rust's pointer types:
 
-| Type         | Name                | Summary                                   |
-|--------------|---------------------|-------------------------------------------|
-| `&T`         | Reference           | Allows one or more references to read `T` |
-| `&mut T`     | Mutable Reference   | Allows a single reference to              |
-|              |                     | read and write `T`                        |
-| `Box<T>`     | Box                 | Heap allocated `T` with a single owner    |
-|              |                     | that may read and write `T`.              |
-| `Rc<T>`      | "arr cee" pointer   | Heap allocated `T` with many readers      |
-| `Arc<T>`     | Arc pointer         | Same as above, but safe sharing across    |
-|              |                     | threads                                   |
-| `*const T`   | Raw pointer         | Unsafe read access to `T`                 |
-| `*mut T`     | Mutable raw pointer | Unsafe read and write access to `T`       |
+| Type         | Name                | Summary                                                             |
+|--------------|---------------------|---------------------------------------------------------------------|
+| `&T`         | Reference           | Allows one or more references to read `T`                           |
+| `&mut T`     | Mutable Reference   | Allows a single reference to read and write `T`                     |
+| `Box<T>`     | Box                 | Heap allocated `T` with a single owner that may read and write `T`. |
+| `Rc<T>`      | "arr cee" pointer   | Heap allocated `T` with many readers                                |
+| `Arc<T>`     | Arc pointer         | Same as above, but safe sharing across threads                      |
+| `*const T`   | Raw pointer         | Unsafe read access to `T`                                           |
+| `*mut T`     | Mutable raw pointer | Unsafe read and write access to `T`                                 |
 
 # Related resources
 

branches/try2/src/doc/tutorial.md

@@ -1503,7 +1503,7 @@ reference. We also call this _borrowing_ the local variable
 `on_the_stack`, because we are creating an alias: that is, another
 route to the same data.
 
-Likewise, in the case of `owned_box`,
+Likewise, in the case of `on_the_heap`,
 the `&` operator is used in conjunction with the `*` operator
 to take a reference to the contents of the box.
 

branches/try2/src/liballoc/rc.rs

@@ -150,18 +150,18 @@ fn main() {
 
 #![stable]
 
-use core::mem::transmute;
 use core::cell::Cell;
 use core::clone::Clone;
 use core::cmp::{PartialEq, PartialOrd, Eq, Ord, Ordering};
 use core::default::Default;
+use core::fmt;
 use core::kinds::marker;
+use core::mem::{transmute, min_align_of, size_of, forget};
 use core::ops::{Deref, Drop};
 use core::option::{Option, Some, None};
 use core::ptr;
 use core::ptr::RawPtr;
-use core::mem::{min_align_of, size_of};
-use core::fmt;
+use core::result::{Result, Ok, Err};
 
 use heap::deallocate;
 
@@ -218,6 +218,76 @@ impl<T> Rc<T> {
     }
 }
 
+/// Returns true if the `Rc` currently has unique ownership.
+///
+/// Unique ownership means that there are no other `Rc` or `Weak` values
+/// that share the same contents.
+#[inline]
+#[experimental]
+pub fn is_unique<T>(rc: &Rc<T>) -> bool {
+    // note that we hold both a strong and a weak reference
+    rc.strong() == 1 && rc.weak() == 1
+}
+
+/// Unwraps the contained value if the `Rc` has unique ownership.
+///
+/// If the `Rc` does not have unique ownership, `Err` is returned with the
+/// same `Rc`.
+///
+/// # Example:
+///
+/// ```
+/// use std::rc::{mod, Rc};
+/// let x = Rc::new(3u);
+/// assert_eq!(rc::try_unwrap(x), Ok(3u));
+/// let x = Rc::new(4u);
+/// let _y = x.clone();
+/// assert_eq!(rc::try_unwrap(x), Err(Rc::new(4u)));
+/// ```
+#[inline]
+#[experimental]
+pub fn try_unwrap<T>(rc: Rc<T>) -> Result<T, Rc<T>> {
+    if is_unique(&rc) {
+        unsafe {
+            let val = ptr::read(&*rc); // copy the contained object
+            // destruct the box and skip our Drop
+            // we can ignore the refcounts because we know we're unique
+            deallocate(rc._ptr as *mut u8, size_of::<RcBox<T>>(),
+                        min_align_of::<RcBox<T>>());
+            forget(rc);
+            Ok(val)
+        }
+    } else {
+        Err(rc)
+    }
+}
+
+/// Returns a mutable reference to the contained value if the `Rc` has
+/// unique ownership.
+///
+/// Returns `None` if the `Rc` does not have unique ownership.
+///
+/// # Example:
+///
+/// ```
+/// use std::rc::{mod, Rc};
+/// let mut x = Rc::new(3u);
+/// *rc::get_mut(&mut x).unwrap() = 4u;
+/// assert_eq!(*x, 4u);
+/// let _y = x.clone();
+/// assert!(rc::get_mut(&mut x).is_none());
+/// ```
+#[inline]
+#[experimental]
+pub fn get_mut<'a, T>(rc: &'a mut Rc<T>) -> Option<&'a mut T> {
+    if is_unique(rc) {
+        let inner = unsafe { &mut *rc._ptr };
+        Some(&mut inner.value)
+    } else {
+        None
+    }
+}
+
 impl<T: Clone> Rc<T> {
     /// Acquires a mutable pointer to the inner contents by guaranteeing that
     /// the reference count is one (no sharing is possible).
@@ -226,12 +296,9 @@ impl<T: Clone> Rc<T> {
     /// data is cloned if the reference count is greater than one.
     #[inline]
     #[experimental]
-    pub fn make_unique<'a>(&'a mut self) -> &'a mut T {
-        // Note that we hold a strong reference, which also counts as
-        // a weak reference, so we only clone if there is an
-        // additional reference of either kind.
-        if self.strong() != 1 || self.weak() != 1 {
-            *self = Rc::new(self.deref().clone())
+    pub fn make_unique(&mut self) -> &mut T {
+        if !is_unique(self) {
+            *self = Rc::new((**self).clone())
         }
         // This unsafety is ok because we're guaranteed that the pointer
         // returned is the *only* pointer that will ever be returned to T. Our
@@ -247,7 +314,7 @@ impl<T: Clone> Rc<T> {
 impl<T> Deref<T> for Rc<T> {
     /// Borrow the value contained in the reference-counted box
     #[inline(always)]
-    fn deref<'a>(&'a self) -> &'a T {
+    fn deref(&self) -> &T {
         &self.inner().value
     }
 }
@@ -260,7 +327,7 @@ impl<T> Drop for Rc<T> {
             if !self._ptr.is_null() {
                 self.dec_strong();
                 if self.strong() == 0 {
-                    ptr::read(self.deref()); // destroy the contained object
+                    ptr::read(&**self); // destroy the contained object
 
                     // remove the implicit "strong weak" pointer now
                     // that we've destroyed the contents.
@@ -390,7 +457,7 @@ impl<T> Clone for Weak<T> {
 
 #[doc(hidden)]
 trait RcBoxPtr<T> {
-    fn inner<'a>(&'a self) -> &'a RcBox<T>;
+    fn inner(&self) -> &RcBox<T>;
 
     #[inline]
     fn strong(&self) -> uint { self.inner().strong.get() }
@@ -413,12 +480,12 @@ trait RcBoxPtr<T> {
 
 impl<T> RcBoxPtr<T> for Rc<T> {
     #[inline(always)]
-    fn inner<'a>(&'a self) -> &'a RcBox<T> { unsafe { &(*self._ptr) } }
+    fn inner(&self) -> &RcBox<T> { unsafe { &(*self._ptr) } }
 }
 
 impl<T> RcBoxPtr<T> for Weak<T> {
     #[inline(always)]
-    fn inner<'a>(&'a self) -> &'a RcBox<T> { unsafe { &(*self._ptr) } }
+    fn inner(&self) -> &RcBox<T> { unsafe { &(*self._ptr) } }
 }
 
 #[cfg(test)]
@@ -427,6 +494,7 @@ mod tests {
     use super::{Rc, Weak};
     use std::cell::RefCell;
     use std::option::{Option, Some, None};
+    use std::result::{Err, Ok};
     use std::mem::drop;
     use std::clone::Clone;
 
@@ -494,6 +562,45 @@ mod tests {
         // hopefully we don't double-free (or leak)...
     }
 
+    #[test]
+    fn is_unique() {
+        let x = Rc::new(3u);
+        assert!(super::is_unique(&x));
+        let y = x.clone();
+        assert!(!super::is_unique(&x));
+        drop(y);
+        assert!(super::is_unique(&x));
+        let w = x.downgrade();
+        assert!(!super::is_unique(&x));
+        drop(w);
+        assert!(super::is_unique(&x));
+    }
+
+    #[test]
+    fn try_unwrap() {
+        let x = Rc::new(3u);
+        assert_eq!(super::try_unwrap(x), Ok(3u));
+        let x = Rc::new(4u);
+        let _y = x.clone();
+        assert_eq!(super::try_unwrap(x), Err(Rc::new(4u)));
+        let x = Rc::new(5u);
+        let _w = x.downgrade();
+        assert_eq!(super::try_unwrap(x), Err(Rc::new(5u)));
+    }
+
+    #[test]
+    fn get_mut() {
+        let mut x = Rc::new(3u);
+        *super::get_mut(&mut x).unwrap() = 4u;
+        assert_eq!(*x, 4u);
+        let y = x.clone();
+        assert!(super::get_mut(&mut x).is_none());
+        drop(y);
+        assert!(super::get_mut(&mut x).is_some());
+        let _w = x.downgrade();
+        assert!(super::get_mut(&mut x).is_none());
+    }
+
     #[test]
     fn test_cowrc_clone_make_unique() {
         let mut cow0 = Rc::new(75u);