The Listener trait takes two type parameters, the type of connection and the type of Acceptor,
and specifies only one method, listen, which consumes the listener and produces an Acceptor.
The Acceptor trait takes one type parameter, the type of connection, and defines two methods.
The accept() method waits for an incoming connection attempt and returns the result.
The incoming() method creates an iterator over incoming connections and is a default method.
Example:
```rust
let listener = TcpListener.bind(addr); // Bind to a socket
let acceptor = listener.listen(); // Start the listener
for stream in acceptor.incoming() {
// Process incoming connections forever (a failure will kill the task).
}
```
Closes#8689
Storing the type name in the `tydesc` aims to avoid the need to pass a type name in almost every single visitor method.
It would likely be much saner for `repr` to simply be passed the `TyDesc` corresponding to the function or just the type name, but this is good enough for now.
The message of the first commit explains (edited for changed trait name):
The trait `ExactSize` is introduced to solve a few small niggles:
* We can't reverse (`.invert()`) an enumeration iterator
* for a vector, we have `v.iter().position(f)` but `v.rposition(f)`.
* We can't reverse `Zip` even if both iterators are from vectors
`ExactSize` is an empty trait that is intended to indicate that an
iterator, for example `VecIterator`, knows its exact finite size and
reports it correctly using `.size_hint()`. Only adaptors that preserve
this at all times, can expose this trait further. (Where here we say
finite for fitting in uint).
---
It may seem complicated just to solve these small "niggles",
(It's really the reversible enumerate case that's the most interesting)
but only a few core iterators need to implement this trait.
While we gain more capabilities generically for some iterators,
it becomes a tad more complicated to figure out if a type has
the right trait impls for it.
Address discussion with acrichto; inherit DoubleEndedIterator so that
`.rposition()` can be a default method, and that the nische of the trait
is clear. Use assertions when using `.size_hint()` in reverse enumerate
and `.rposition()`
Summary:
-removed "ne" methods in libstd and librustpkg
-made default "ne" be inlined
-made one of the "eq" methods in librustpkg follow more standard parameter naming convention
This is a generalization of the vector .rposition() method, to all
double-ended iterators that have the ExactSizeHint trait.
This resolves the slight asymmetry around `position` and `rposition`
* position from front is `vec.iter().position()`
* position from the back was, `vec.rposition()` is now `vec.iter().rposition()`
Additionally, other indexed sequences (only `extra::ringbuf` I think),
will have the same method available once it implements ExactSizeHint.
The trait `ExactSizeHint` is introduced to solve a few small niggles:
* We can't reverse (`.invert()`) an enumeration iterator
* for a vector, we have `v.iter().position(f)` but `v.rposition(f)`.
* We can't reverse `Zip` even if both iterators are from vectors
`ExactSizeHint` is an empty trait that is intended to indicate that an
iterator, for example `VecIterator`, knows its exact finite size and
reports it correctly using `.size_hint()`. Only adaptors that preserve
this at all times, can expose this trait further. (Where here we say
finite for fitting in uint).
Fix a bug in `s.slice_chars(a, b)` that did not accept `a == s.len()`.
Fix a bug in `!=` defined for DList.
Also simplify NormalizationIterator to use the CharIterator directly instead of mimicing the iteration itself.
These are very easy to replace with methods on string slices, basically
`.char_len()` and `.len()`.
These are the replacement implementations I did to clean these
functions up, but seeing this I propose removal:
/// ...
pub fn count_chars(s: &str, begin: uint, end: uint) -> uint {
// .slice() checks the char boundaries
s.slice(begin, end).char_len()
}
/// Counts the number of bytes taken by the first `n` chars in `s`
/// starting from byte index `begin`.
///
/// Fails if there are less than `n` chars past `begin`
pub fn count_bytes<'b>(s: &'b str, begin: uint, n: uint) -> uint {
s.slice_from(begin).slice_chars(0, n).len()
}
The only user-facing change is handling non-integer (and zero) `RUST_THREADS` more nicely:
```
$ RUST_THREADS=x rustc # old
You've met with a terrible fate, haven't you?
fatal runtime error: runtime tls key not initialized
Aborted
$ RUST_THREADS=x ./x86_64-unknown-linux-gnu/stage2/bin/rustc # new
You've met with a terrible fate, haven't you?
fatal runtime error: `RUST_THREADS` is `x`, should be a positive integer
Aborted
```
The other changes are converting some `for .. in range(x,y)` to `vec::from_fn` or `for .. in x.iter()` as appropriate; and removing a chain of (seemingly) unnecessary pointer casts.
(Also, fixes a typo in `extra::test` from #8823.)
Python's zip() short-circuits by not even querying its right-hand
iterator if the left-hand one is done. Match that behavior here by not
calling .next() on the right iterator if the left one returns None.
Document the fact that the iterator protocol only defines behavior up
until the first None is returned. After this point, iterators are free
to behave how they wish.
Add a new iterator adaptor Fuse<T> that modifies iterators to return
None forever if they returned None once.
