This adds an example from mem::swap, and provides some suggested uses of this
function.
This is my attempt to summarize the answers to a question I asked on reddit http://www.reddit.com/r/rust/comments/37jcul/what_is_forget_for/ and add the answers to the documentation so that no one else has to google or ask the question again.
This commit implements a number of standard traits for the standard library's
process I/O handles. The `FromRaw{Fd,Handle}` traits are now implemented for the
`Stdio` type and the `AsRaw{Fd,Handle}` traits are now implemented for the
`Child{Stdout,Stdin,Stderr}` types.
The stability markers for these implementations mention that they are stable for
1.1 as I will nominate this commit for cherry-picking to beta.
This takes the cases from InvalidInput where a data format error
was encountered. This is different from the documented semantics
of InvalidInput, which more likely indicate a programming error.
This adds an example from mem::swap, and provides some suggested uses of this
function.
Change wording on comment on forget line to be more specific as to why we
need to call forget.
This breaks the examples up into three pieces. The last piece isn't
compiling for some reason.
The previous feature gate assumed we would not define any (stable) const fns. But then @eddyb went and cleaned up the code. So this now extends the feature-gate to prohibit calls; but calls inside of macros are considered ok.
r? @alexcrichton
For slightly complex data structures like `rustc_serialize::json::Json`, it is often convenient to have helper methods like `Json::as_string(&self) -> Option<&str>` that return a borrow of some component of `&self`.
However, when `RefCell`s are involved, keeping a `Ref` around is required to hold a borrow to the insides of a `RefCell`. But `Ref` so far only references the entirety of the contents of a `RefCell`, not a component. But there is no reason it couldn’t: `Ref` internally contains just a data reference and a borrow count reference. The two can be dissociated.
This adds a `map_ref` function that creates a new `Ref` for some other data, but borrowing the same `RefCell` as an existing `Ref`.
Example:
```rust
struct RefCellJson(RefCell<Json>);
impl RefCellJson {
fn as_string(&self) -> Option<Ref<str>> {
map_ref(self.borrow(), |j| j.as_string())
}
}
```
r? @alexcrichton
The first commit simply forwards `io::Error`'s `cause` implementation to the inner error.
The second commit adds accessor methods for the inner error. Method names mirror those used elsewhere like `BufReader`.
r? @alexcrichton
The compiler already has special support for fixing up verbatim paths with disks
on Windows to something that can be correctly passed down to gcc, and this
commit adds support for verbatim UNC paths as well.
Closes#25505
The current version of hoedown treats lists interrupting paragraphs in the Markdown.pl style rather than CommonMark, so a newline is needed for the list to be rendered properly.
`core::cell::Cell<T>` and `core::cell::RefCell<T>` currently implement `PartialEq` when `T` does, and just defer to comparing `T` values. There is no reason the same shouldn’t apply to `Eq`.
This enables `#[derive(Eq, PartialEq)]` on e.g. structs that have a `RefCell` field.
r? @alexcrichton
I’m unsure what to do with `#[stable]` attributes on `impl`s. `impl`s generated by `#[derive]` don’t have them.
collections: Make BinaryHeap panic safe in sift_up / sift_down
Use a struct called Hole that keeps track of an invalid location
in the vector and fills the hole on drop.
I include a run-pass test that the current BinaryHeap fails, and the new
one passes.
NOTE: The BinaryHeap will still be inconsistent after a comparison fails. It will
not have the heap property. What we fix is just that elements will be valid
values.
This is actually a performance win -- the new code does not bother to write in `zeroed()`
values in the holes, it just leaves them as they were.
Net result is something like a 5% decrease in runtime for `BinaryHeap::from_vec`. This
can be further improved by using unchecked indexing (I confirmed it makes a difference,
not a surprise with the non-sequential access going on), but let's leave that for another PR.
Safety first 😉Fixes#25842
Use a struct called Hole that keeps track of an invalid location
in the vector and fills the hole on drop.
I include a run-pass test that the current BinaryHeap fails, and the new
one passes.
Fixes#25842
