This flag is somewhat tied to the `unwind` module rather than the `thread_info`
module, so this commit moves it into that module as well as allowing the same OS
thread to call `unwind::try` multiple times. Previously once a thread panicked
its panic flag was never reset, even after exiting the panic handler.
The current implementations use `std::sync` primitives, but these primitives
currently end up relying on `thread_info` and a local `Thread` being available
(mainly for checking the panicking flag).
To get around this, this commit lowers the abstractions used by the windows
thread_local implementation as well as the at_exit_imp module. Both of these
modules now use a `sys::Mutex` and a `static mut` and manage the
allocation/locking manually.
This commit is part of a series that introduces a `std::thread` API to
replace `std::task`.
In the new API, `spawn` returns a `JoinGuard`, which by default will
join the spawned thread when dropped. It can also be used to join
explicitly at any time, returning the thread's result. Alternatively,
the spawned thread can be explicitly detached (so no join takes place).
As part of this change, Rust processes now terminate when the main
thread exits, even if other detached threads are still running, moving
Rust closer to standard threading models. This new behavior may break code
that was relying on the previously implicit join-all.
In addition to the above, the new thread API also offers some built-in
support for building blocking abstractions in user space; see the module
doc for details.
Closes#18000
[breaking-change]
This commit removes the runtime bookkeeping previously used to ensure
that all Rust tasks were joined before the runtime was shut down.
This functionality will be replaced by an RAII style `Thread` API, that
will also offer a detached mode.
Since this changes the semantics of shutdown, it is a:
[breaking-change]
This commit merges the `rustrt` crate into `std`, undoing part of the
facade. This merger continues the paring down of the runtime system.
Code relying on the public API of `rustrt` will break; some of this API
is now available through `std::rt`, but is likely to change and/or be
removed very soon.
[breaking-change]
followed by a semicolon.
This allows code like `vec![1i, 2, 3].len();` to work.
This breaks code that uses macros as statements without putting
semicolons after them, such as:
fn main() {
...
assert!(a == b)
assert!(c == d)
println(...);
}
It also breaks code that uses macros as items without semicolons:
local_data_key!(foo)
fn main() {
println("hello world")
}
Add semicolons to fix this code. Those two examples can be fixed as
follows:
fn main() {
...
assert!(a == b);
assert!(c == d);
println(...);
}
local_data_key!(foo);
fn main() {
println("hello world")
}
RFC #378.
Closes#18635.
[breaking-change]
Now that we have an overloaded comparison (`==`) operator, and that `Vec`/`String` deref to `[T]`/`str` on method calls, many `as_slice()`/`as_mut_slice()`/`to_string()` calls have become redundant. This patch removes them. These were the most common patterns:
- `assert_eq(test_output.as_slice(), "ground truth")` -> `assert_eq(test_output, "ground truth")`
- `assert_eq(test_output, "ground truth".to_string())` -> `assert_eq(test_output, "ground truth")`
- `vec.as_mut_slice().sort()` -> `vec.sort()`
- `vec.as_slice().slice(from, to)` -> `vec.slice(from_to)`
---
Note that e.g. `a_string.push_str(b_string.as_slice())` has been left untouched in this PR, since we first need to settle down whether we want to favor the `&*b_string` or the `b_string[]` notation.
This is rebased on top of #19167
cc @alexcrichton @aturon
In regards to:
https://github.com/rust-lang/rust/issues/19253#issuecomment-64836729
This commit:
* Changes the #deriving code so that it generates code that utilizes fewer
reexports (in particur Option::* and Result::*), which is necessary to
remove those reexports in the future
* Changes other areas of the codebase so that fewer reexports are utilized
After the library successfully called `fork(2)`, the child does several
setup works such as setting UID, GID and current directory before it
calls `exec(2)`. When those setup works failed, the child exits but the
parent didn't call `waitpid(2)` and left it as a zombie.
This patch also add several sanity checks. They shouldn't make any
noticeable impact to runtime performance.
The new test case in `libstd/io/process.rs` calls the ps command to check
if the new code can really reap a zombie.
The output of `ps -A -o pid,sid,command` should look like this:
```
PID SID COMMAND
1 1 /sbin/init
2 0 [kthreadd]
3 0 [ksoftirqd/0]
...
12562 9237 ./spawn-failure
12563 9237 [spawn-failure] <defunct>
12564 9237 [spawn-failure] <defunct>
...
12592 9237 [spawn-failure] <defunct>
12593 9237 ps -A -o pid,sid,command
12884 12884 /bin/zsh
12922 12922 /bin/zsh
...
```
where `./spawn-failure` is my test program which intentionally leaves many
zombies. Filtering the output with the "SID" (session ID) column is
a quick way to tell if a process (zombie) was spawned by my own test
program. Then the number of "defunct" lines is the number of zombie
children.
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 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 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.
[breaking-change]
Closes#17094Closes#18003
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.
[breaking-change]
Closes#17094Closes#18003
This may have inadvertently switched during the runtime overhaul, so this
switches TcpListener back to using sockets instead of file descriptors. This
also renames a bunch of variables called `fd` to `socket` to clearly show that
it's not a file descriptor.
Closes#19333
After the library successfully called fork(2), the child does several
setup works such as setting UID, GID and current directory before it
calls exec(2). When those setup works failed, the child exits but the
parent didn't call waitpid(2) and left it as a zombie.
This patch also add several sanity checks. They shouldn't make any
noticeable impact to runtime performance.
The new test case run-pass/wait-forked-but-failed-child.rs calls the ps
command to check if the new code can really reap a zombie. When
I intentionally create many zombies with my test program
./spawn-failure, The output of "ps -A -o pid,sid,command" should look
like this:
PID SID COMMAND
1 1 /sbin/init
2 0 [kthreadd]
3 0 [ksoftirqd/0]
...
12562 9237 ./spawn-failure
12563 9237 [spawn-failure] <defunct>
12564 9237 [spawn-failure] <defunct>
...
12592 9237 [spawn-failure] <defunct>
12593 9237 ps -A -o pid,sid,command
12884 12884 /bin/zsh
12922 12922 /bin/zsh
...
Filtering the output with the "SID" (session ID) column is a quick way
to tell if a process (zombie) was spawned by my own test program. Then
the number of "defunct" lines is the number of zombie children.
Signed-off-by: NODA, Kai <nodakai@gmail.com>
All of the enum components had a redundant 'Type' specifier: TypeSymlink, TypeDirectory, TypeFile. This change removes them, replacing them with a namespace: FileType::Symlink, FileType::Directory, and FileType::RegularFile.
RegularFile is used instead of just File, as File by itself could be mistakenly thought of as referring to the struct.
Part of #19253.
This is an initial pass at stabilizing the `iter` module. The module is
fairly large, but is also pretty polished, so most of the stabilization
leaves things as they are.
Some changes:
* Due to the new object safety rules, various traits needs to be split
into object-safe traits and extension traits. This includes `Iterator`
itself. While splitting up the traits adds some complexity, it will
also increase flexbility: once we have automatic impls of `Trait` for
trait objects over `Trait`, then things like the iterator adapters
will all work with trait objects.
* Iterator adapters that use up the entire iterator now take it by
value, which makes the semantics more clear and helps catch bugs. Due
to the splitting of Iterator, this does not affect trait objects. If
the underlying iterator is still desired for some reason, `by_ref` can
be used. (Note: this change had no fallout in the Rust distro except
for the useless mut lint.)
* In general, extension traits new and old are following an [in-progress
convention](rust-lang/rfcs#445). As such, they
are marked `unstable`.
* As usual, anything involving closures is `unstable` pending unboxed
closures.
* A few of the more esoteric/underdeveloped iterator forms (like
`RandomAccessIterator` and `MutableDoubleEndedIterator`, along with
various unfolds) are left experimental for now.
* The `order` submodule is left `experimental` because it will hopefully
be replaced by generalized comparison traits.
* "Leaf" iterators (like `Repeat` and `Counter`) are uniformly
constructed by free fns at the module level. That's because the types
are not otherwise of any significance (if we had `impl Trait`, you
wouldn't want to define a type at all).
Closes#17701
Due to renamings and splitting of traits, this is a:
[breaking-change]
This PR adds some internal infrastructure to allow the private `std::sys` module to access internal representation details of `std::io`.
It then exposes those details in two new, platform-specific API surfaces: `std::os::unix` and `std::os::windows`.
To start with, these will provide the ability to extract file descriptors, HANDLEs, SOCKETs, and so on from `std::io` types.
More functionality, and more specific platforms (e.g. `std::os::linux`) will be added over time.
Closes#18897
It turns out that rustrt::at_exit() doesn't actually occur after all pthread
threads have exited (nor does atexit()), so there's not actually a known point
at which we can deallocate these keys. It's not super critical that we do so,
however, because we're about to exit anyway!
Closes#19280
All of the enum components had a redundant 'Type' specifier: TypeSymlink, TypeDirectory, TypeFile. This change removes them, replacing them with a namespace: FileType::Symlink, FileType::Directory, and FileType::RegularFile.
RegularFile is used instead of just File, as File by itself could be mistakenly thought of as referring to the struct.
[breaking-change]
This commit removes the `std::local_data` module in favor of a new
`std::thread_local` module providing thread local storage. The module provides
two variants of TLS: one which owns its contents and one which is based on
scoped references. Each implementation has pros and cons listed in the
documentation.
Both flavors have accessors through a function called `with` which yield a
reference to a closure provided. Both flavors also panic if a reference cannot
be yielded and provide a function to test whether an access would panic or not.
This is an implementation of [RFC 461][rfc] and full details can be found in
that RFC.
This is a breaking change due to the removal of the `std::local_data` module.
All users can migrate to the new thread local system like so:
thread_local!(static FOO: Rc<RefCell<Option<T>>> = Rc::new(RefCell::new(None)))
The old `local_data` module inherently contained the `Rc<RefCell<Option<T>>>` as
an implementation detail which must now be explicitly stated by users.
[rfc]: https://github.com/rust-lang/rfcs/pull/461
[breaking-change]
This commit is an implementation of [RFC 240][rfc] when applied to the standard
library. It primarily deprecates the entirety of `string::raw`, `vec::raw`,
`slice::raw`, and `str::raw` in favor of associated functions, methods, and
other free functions. The detailed renaming is:
* slice::raw::buf_as_slice => slice::from_raw_buf
* slice::raw::mut_buf_as_slice => slice::from_raw_mut_buf
* slice::shift_ptr => deprecated with no replacement
* slice::pop_ptr => deprecated with no replacement
* str::raw::from_utf8 => str::from_utf8_unchecked
* str::raw::c_str_to_static_slice => str::from_c_str
* str::raw::slice_bytes => deprecated for slice_unchecked (slight semantic diff)
* str::raw::slice_unchecked => str.slice_unchecked
* string::raw::from_parts => String::from_raw_parts
* string::raw::from_buf_len => String::from_raw_buf_len
* string::raw::from_buf => String::from_raw_buf
* string::raw::from_utf8 => String::from_utf8_unchecked
* vec::raw::from_buf => Vec::from_raw_buf
All previous functions exist in their `#[deprecated]` form, and the deprecation
messages indicate how to migrate to the newer variants.
[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0240-unsafe-api-location.md
[breaking-change]
Closes#17863
