Alex Crichton [Mon, 24 Nov 2014 19:16:40 +0000 (11:16 -0800)]
std: Rewrite the `sync` module
This commit is a reimplementation of `std::sync` to be based on the
system-provided primitives wherever possible. The previous implementation was
fundamentally built on top of channels, and as part of the runtime reform it has
become clear that this is not the level of abstraction that the standard level
should be providing. This rewrite aims to provide as thin of a shim as possible
on top of the system primitives in order to make them safe.
The overall interface of the `std::sync` module has in general not changed, but
there are a few important distinctions, highlighted below:
* The condition variable type, `Condvar`, has been separated out of a `Mutex`.
A condition variable is now an entirely separate type. This separation
benefits users who only use one mutex, and provides a clearer distinction of
who's responsible for managing condition variables (the application).
* All of `Condvar`, `Mutex`, and `RWLock` are now directly built on top of
system primitives rather than using a custom implementation. The `Once`,
`Barrier`, and `Semaphore` types are still built upon these abstractions of
the system primitives.
* The `Condvar`, `Mutex`, and `RWLock` types all have a new static type and
constant initializer corresponding to them. These are provided primarily for C
FFI interoperation, but are often useful to otherwise simply have a global
lock. The types, however, will leak memory unless `destroy()` is called on
them, which is clearly documented.
* The `Condvar` implementation for an `RWLock` write lock has been removed. This
may be added back in the future with a userspace implementation, but this
commit is focused on exposing the system primitives first.
* The fundamental architecture of this design is to provide two separate layers.
The first layer is that exposed by `sys_common` which is a cross-platform
bare-metal abstraction of the system synchronization primitives. No attempt is
made at making this layer safe, and it is quite unsafe to use! It is currently
not exported as part of the API of the standard library, but the stabilization
of the `sys` module will ensure that these will be exposed in time. The
purpose of this layer is to provide the core cross-platform abstractions if
necessary to implementors.
The second layer is the layer provided by `std::sync` which is intended to be
the thinnest possible layer on top of `sys_common` which is entirely safe to
use. There are a few concerns which need to be addressed when making these
system primitives safe:
* Once used, the OS primitives can never be **moved**. This means that they
essentially need to have a stable address. The static primitives use
`&'static self` to enforce this, and the non-static primitives all use a
`Box` to provide this guarantee.
* Poisoning is leveraged to ensure that invalid data is not accessible from
other tasks after one has panicked.
In addition to these overall blanket safety limitations, each primitive has a
few restrictions of its own:
* Mutexes and rwlocks can only be unlocked from the same thread that they
were locked by. This is achieved through RAII lock guards which cannot be
sent across threads.
* Mutexes and rwlocks can only be unlocked if they were previously locked.
This is achieved by not exposing an unlocking method.
* A condition variable can only be waited on with a locked mutex. This is
achieved by requiring a `MutexGuard` in the `wait()` method.
* A condition variable cannot be used concurrently with more than one mutex.
This is guaranteed by dynamically binding a condition variable to
precisely one mutex for its entire lifecycle. This restriction may be able
to be relaxed in the future (a mutex is unbound when no threads are
waiting on the condvar), but for now it is sufficient to guarantee safety.
* Condvars now support timeouts for their blocking operations. The
implementation for these operations is provided by the system.
Due to the modification of the `Condvar` API, removal of the `std::sync::mutex`
API, and reimplementation, this is a breaking change. Most code should be fairly
easy to port using the examples in the documentation of these primitives.
bors [Fri, 5 Dec 2014 00:22:58 +0000 (00:22 +0000)]
auto merge of #19303 : nodakai/rust/libsyntax-reject-dirs, r=alexcrichton
On *BSD systems, we can `open(2)` a directory and directly `read(2)` from it due to an old tradition. We should avoid doing so by explicitly calling `fstat(2)` to check the type of the opened file.
Opening a directory as a module file can't always be avoided. Even when there's no "path" attribute trick involved, there can always be a *directory* named `my_module.rs`.
Incidentally, remove unnecessary mutability of `&self` from `io::fs::File::stat()`.
bors [Thu, 4 Dec 2014 21:33:07 +0000 (21:33 +0000)]
auto merge of #18980 : erickt/rust/reader, r=erickt
This continues the work @thestinger started in #18885 (which hasn't landed yet, so wait for that to land before landing this one). Instead of adding more methods to `BufReader`, this just allows a `&[u8]` to be used directly as a `Reader`. It also adds an impl of `Writer` for `&mut [u8]`.
bors [Thu, 4 Dec 2014 12:02:56 +0000 (12:02 +0000)]
auto merge of #19167 : japaric/rust/rhs-cmp, r=aturon
Comparison traits have gained an `Rhs` input parameter that defaults to `Self`. And now the comparison operators can be overloaded to work between different types. In particular, this PR allows the following operations (and their commutative versions):
Where `A`, `B`, `C`, `D`, `E` may be different types that implement `PartialEq`. For example, these comparisons are now valid: `string == "foo"`, and `vec_of_strings == ["Hello", "world"]`.
[breaking-change]s
Since the `==` may now work on different types, operations that relied on the old "same type restriction" to drive type inference, will need to be type annotated. These are the most common fallout cases:
- `some_vec == some_iter.collect()`: `collect` needs to be type annotated: `collect::<Vec<_>>()`
- `slice == &[a, b, c]`: RHS doesn't get coerced to an slice, use an array instead `[a, b, c]`
- `lhs == []`: Change expression to `lhs.is_empty()`
- `lhs == some_generic_function()`: Type annotate the RHS as necessary
bors [Thu, 4 Dec 2014 08:52:47 +0000 (08:52 +0000)]
auto merge of #19449 : nikomatsakis/rust/unboxed-closure-fn-impl, r=pcwalton
Implement the `Fn` trait for bare fn pointers in the compiler rather
than doing it using hard-coded impls. This means that it works also
for more complex fn types involving bound regions.
Niko Matsakis [Mon, 1 Dec 2014 14:23:40 +0000 (09:23 -0500)]
Implement the `Fn` trait for bare fn pointers in the compiler rather than doing it using hard-coded impls. This means that it works also for more complex fn types involving bound regions. Fixes #19126.
bors [Thu, 4 Dec 2014 04:52:37 +0000 (04:52 +0000)]
auto merge of #18613 : steveklabnik/rust/ownership_guide, r=huonw
This is a work in progress, but this should get *extensive* review, so I'm putting it up early and often.
This is the start of a draft of the new 'ownership guide,' which explains ownership, borrowing, etc. I'm feeling better about this framing than last time's, but we'll see.
NODA, Kai [Tue, 2 Dec 2014 22:06:59 +0000 (06:06 +0800)]
libstd: explicitly disallow io::fs::File to open a directory.
On *BSD systems, we can open(2) a directory and directly read(2) from
it due to an old tradition. We should avoid doing so by explicitly
calling fstat(2) to check the type of the opened file.
Opening a directory as a module file can't always be avoided.
Even when there's no "path" attribute trick involved, there can always
be a *directory* named "my_module.rs".
Erick Tryzelaar [Mon, 1 Dec 2014 07:34:19 +0000 (23:34 -0800)]
rustup: rewrite to protect against truncation
This closes #19168. It's possible that if the downloading of `rustup.sh`
is interrupted, bad things could happen, such as running a naked
"rm -rf /" instead of "rm -rf /path/to/tmpdir". This wraps rustup.sh's
functionality in a function that gets called at the last time that should
protect us from these truncation errors.
bors [Wed, 3 Dec 2014 22:57:40 +0000 (22:57 +0000)]
auto merge of #18749 : nikomatsakis/rust/builtin-bounds-like-other-traits, r=pcwalton
Treat builtin bounds like all other kinds of trait matches. Introduce a simple hashset in the fulfillment context to catch cases where we register the exact same obligation twice. This helps prevent duplicate error reports but also handles the recursive obligations created by builtin bounds.
Niko Matsakis [Sat, 8 Nov 2014 01:23:33 +0000 (20:23 -0500)]
Correct various compile-fail tests. Most of the changes are because we
now don't print duplicate errors within one context, so I sometimes
had to break functions into two functions.
Niko Matsakis [Fri, 7 Nov 2014 21:14:32 +0000 (16:14 -0500)]
Treat builtin bounds like all other kinds of trait matches. Introduce a simple hashset in the fulfillment context to catch cases where we register the exact same obligation twice. This helps prevent duplicate error reports but also handles the recursive obligations created by builtin bounds.
bors [Tue, 2 Dec 2014 10:06:58 +0000 (10:06 +0000)]
auto merge of #19357 : michaelwoerister/rust/fix-issue-18791, r=alexcrichton
One negative side-effect of this change is that there might be quite a bit of copying strings out of the codemap, i.e. one copy for every block that gets translated, just for taking a look at the last character of the block. If this turns out to cause a performance problem then `CodeMap::span_to_snippet()` could be changed return `Option<&str>` instead of `Option<String>`.
bors [Tue, 2 Dec 2014 02:52:15 +0000 (02:52 +0000)]
auto merge of #19450 : jbapple/rust/pq-pop-time, r=Gankro
pop calls siftdown, siftdown calls siftdown_range, and siftdown_range
loops on an index that can start as low as 0 and approximately doubles
each iteration.
Jim Apple [Tue, 2 Dec 2014 02:12:48 +0000 (18:12 -0800)]
Pop on binary heaps does not have constant time complexity.
pop calls siftdown, siftdown calls siftdown_range, and siftdown_range
loops on an index that can start as low as 0 and approximately doubles
each iteration.
If the source code is in the parent dirs relative to the crate root, `..` is replaced with `up` as expected. Any other error like non-UTF-8 paths or drive-relative paths falls back to the absolute path.
There might be a way to improve on false negatives, but this alone should be enough for fixing #18370.
If the source code is in the parent dirs relative to the crate root,
`..` is replaced with `up` as expected. Any other error like non-UTF-8
paths or drive-relative paths falls back to the absolute path.
There might be a way to improve on false negatives, but this alone
should be enough for fixing #18370.
bors [Sun, 30 Nov 2014 06:56:41 +0000 (06:56 +0000)]
auto merge of #19365 : frewsxcv/rust/getopts-cleanup, r=alexcrichton
* Remove public reexports, as a part of #19253
* Rename getopts::Fail_ to getopts::Fail
* Didn't see a reason for the suffixed '_'
* Removed getopts::FailType
* Looked like it was only beings used for tests; refactored the tests
to stop requiring it
* A few other non-breaking trivial refactoring changes
bors [Fri, 28 Nov 2014 09:31:24 +0000 (09:31 +0000)]
auto merge of #19363 : michaelwoerister/rust/support-unboxed-closures, r=alexcrichton
This PR lets `rustc` generate debuginfo for variables captured by unboxed closures.
Fixes #19356
@nikomatsakis This PR will probably conflict with #19338. If this gets merged before, you should be able to just leave the test case as it is (maybe remove the `#![feature(unboxed_closures)]` directive).
Corey Farwell [Thu, 27 Nov 2014 19:39:50 +0000 (14:39 -0500)]
getopts: cleanup, renames, remove reexports
* Remove public reexports, as a part of #19253
* Rename getopts::Fail_ to getopts::Fail
* Didn't see a reason for the suffixed '_'
* Removed getopts::FailType
* Looked like it was only beings used for tests; refactored the tests
to stop requiring it
* A few other non-breaking trivial refactoring changes