This PR includes the addition of the essential CRUD functionality exposed as a part of the `uv_fs_*` api. There's a lot more to be done, but the essential abstractions are in place and can be easily expanded.
A summary:
* `rt::io::file::FileStream` is fleshed out and behaves as a *non-positional* file stream (that is, it has a cursor that can be viewed/changed via `tell` and `seek`
* The underlying abstraction in `RtioFileStream` exposes pairs of `read(), write()` and `pread(), pwrite()`. The latter two take explicit `offset` params and don't respect the current cursor location in a file afaik. They both use the same underlying libuv impl
* Because libuv explicitly does *not* support `seek`/`tell` operations, these are impl'd in `UvFileStream` by using `lseek(2)` on the raw file descriptor.
* I did my best to flesh out and adhere to the stubbing that was already present in `rt::io::file` and the tests should back that up. There may be things missing.
* All of the work to test `seek`/`tell` is done in `rt::io::file`, even though the actual impl is down in `rt::uv::uvio`.
* We have the ability to spin up an `~RtioFileStream` from a raw file descriptor. This would be useful for interacting with stdin and stdout via newrt.
* The lowest level abstractions (in `rt::uv::file`) support fully synchronous/blocking interactions with the uv API and there is a CRUD test using it. This may also be useful for blocking printf, if desired (the default would be non-blocking and uses libuv's io threadpool)
There are a few polish things I need to do still (the foremost that I know of is undefined behavior when seek'ing beyond the file's boundary).
After this lands, I want to move on to mapping more of the `uv_fs_*` API (especially `uv_fs_stat`). Also a few people have mentioned interest in `uv_pipe_t` support. I'm open to suggestions.
- change all uses of Path in fn args to &P
- FileStream.read assumptions were wrong (libuv file io is non-positional)
- the above will mean that we "own" Seek impl info .. should probably
push it in UvFileDescriptor..
- needs more tests
This commit removes the "super_*" functions from
typeck::infer::combine, and adds them as default methods on the
Combine trait instead, making it possible to remove a lot of
boilerplate from the various impls of Combine.
I've been wanting to do this for over a year. In fact, it was my
original motivation for default methods!
It might be possible to tighten things up even more, but this is the
bulk of it.
`stdtest` and `extratest` expects to be able to write to `tmp` directory under the current working directory, so the first commit creates `tmp` directory and changes the directory before running tests.
The second commit adds `--bench` argument to test runs and copies metrics from the remote device.
Implement CharIterator as a separate struct, so that it can be .clone()'d. Fix `.char_range_at_reverse` so that it performs better, closer to the forwards version. This makes the reverse iterators and users like `.rfind()` perform better.
Before
test str::bench::char_iterator ... bench: 146 ns/iter (+/- 0)
test str::bench::char_iterator_ascii ... bench: 397 ns/iter (+/- 49)
test str::bench::char_iterator_rev ... bench: 576 ns/iter (+/- 8)
test str::bench::char_offset_iterator ... bench: 128 ns/iter (+/- 2)
test str::bench::char_offset_iterator_rev ... bench: 425 ns/iter (+/- 59)
After
test str::bench::char_iterator ... bench: 130 ns/iter (+/- 1)
test str::bench::char_iterator_ascii ... bench: 307 ns/iter (+/- 5)
test str::bench::char_iterator_rev ... bench: 185 ns/iter (+/- 8)
test str::bench::char_offset_iterator ... bench: 131 ns/iter (+/- 13)
test str::bench::char_offset_iterator_rev ... bench: 183 ns/iter (+/- 2)
To be able to use a string slice to represent the CharIterator, a function `slice_unchecked` is added, that does the same as `slice_bytes` but without any boundary checks.
It would be possible to implement CharIterator with pointer arithmetic to make it *much more efficient*, but since vec iterator is still improving, it's too early to attempt to re-implement it in other places. Hopefully CharIterator can be implemented on top of vec iterator without any unsafe code later.
Additional changes fix the documentation about null termination.
For #7083.
The metadata issue with the old version is now fixed. Ready for review.
This is also not the full solution to #7083, because this is not supported yet:
```
trait Foo : Send { }
impl <T: Send> Foo for T { }
fn foo<T: Foo>(val: T, chan: std::comm::Chan<T>) {
chan.send(val);
}
```
cc @nikomatsakis
