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.
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]
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
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]
Previously, the entire runtime API surface was publicly exposed, but
that is neither necessary nor desirable. This commit hides most of the
module, using librustrt directly as needed. The arrangement will need to
be revisited when rustrt is pulled into std.
[breaking-change]
https://github.com/rust-lang/rfcs/pull/221
The current terminology of "task failure" often causes problems when
writing or speaking about code. You often want to talk about the
possibility of an operation that returns a Result "failing", but cannot
because of the ambiguity with task failure. Instead, you have to speak
of "the failing case" or "when the operation does not succeed" or other
circumlocutions.
Likewise, we use a "Failure" header in rustdoc to describe when
operations may fail the task, but it would often be helpful to separate
out a section describing the "Err-producing" case.
We have been steadily moving away from task failure and toward Result as
an error-handling mechanism, so we should optimize our terminology
accordingly: Result-producing functions should be easy to describe.
To update your code, rename any call to `fail!` to `panic!` instead.
Assuming you have not created your own macro named `panic!`, this
will work on UNIX based systems:
grep -lZR 'fail!' . | xargs -0 -l sed -i -e 's/fail!/panic!/g'
You can of course also do this by hand.
[breaking-change]
This PR is the outcome of the library stabilization meeting for the
`liballoc::owned` and `libcore::cell` modules.
Aside from the stability attributes, there are a few breaking changes:
* The `owned` modules is now named `boxed`, to better represent its
contents. (`box` was unavailable, since it's a keyword.) This will
help avoid the misconception that `Box` plays a special role wrt
ownership.
* The `AnyOwnExt` extension trait is renamed to `BoxAny`, and its `move`
method is renamed to `downcast`, in both cases to improve clarity.
* The recently-added `AnySendOwnExt` extension trait is removed; it was
not being used and is unnecessary.
[breaking-change]
Earlier commits have established a baseline of `experimental` stability
for all crates under the facade (so their contents are considered
experimental within libstd). Since `experimental` is `allow` by
default, we should use the same baseline stability for libstd itself.
This commit adds `experimental` tags to all of the modules defined in
`std`, and `unstable` to `std` itself.
As part of the libstd facade efforts, this commit extracts the runtime interface
out of the standard library into a standalone crate, librustrt. This crate will
provide the following services:
* Definition of the rtio interface
* Definition of the Runtime interface
* Implementation of the Task structure
* Implementation of task-local-data
* Implementation of task failure via unwinding via libunwind
* Implementation of runtime initialization and shutdown
* Implementation of thread-local-storage for the local rust Task
Notably, this crate avoids the following services:
* Thread creation and destruction. The crate does not require the knowledge of
an OS threading system, and as a result it seemed best to leave out the
`rt::thread` module from librustrt. The librustrt module does depend on
mutexes, however.
* Implementation of backtraces. There is no inherent requirement for the runtime
to be able to generate backtraces. As will be discussed later, this
functionality continues to live in libstd rather than librustrt.
As usual, a number of architectural changes were required to make this crate
possible. Users of "stable" functionality will not be impacted by this change,
but users of the `std::rt` module will likely note the changes. A list of
architectural changes made is:
* The stdout/stderr handles no longer live directly inside of the `Task`
structure. This is a consequence of librustrt not knowing about `std::io`.
These two handles are now stored inside of task-local-data.
The handles were originally stored inside of the `Task` for perf reasons, and
TLD is not currently as fast as it could be. For comparison, 100k prints goes
from 59ms to 68ms (a 15% slowdown). This appeared to me to be an acceptable
perf loss for the successful extraction of a librustrt crate.
* The `rtio` module was forced to duplicate more functionality of `std::io`. As
the module no longer depends on `std::io`, `rtio` now defines structures such
as socket addresses, addrinfo fiddly bits, etc. The primary change made was
that `rtio` now defines its own `IoError` type. This type is distinct from
`std::io::IoError` in that it does not have an enum for what error occurred,
but rather a platform-specific error code.
The native and green libraries will be updated in later commits for this
change, and the bulk of this effort was put behind updating the two libraries
for this change (with `rtio`).
* Printing a message on task failure (along with the backtrace) continues to
live in libstd, not in librustrt. This is a consequence of the above decision
to move the stdout/stderr handles to TLD rather than inside the `Task` itself.
The unwinding API now supports registration of global callback functions which
will be invoked when a task fails, allowing for libstd to register a function
to print a message and a backtrace.
The API for registering a callback is experimental and unsafe, as the
ramifications of running code on unwinding is pretty hairy.
* The `std::unstable::mutex` module has moved to `std::rt::mutex`.
* The `std::unstable::sync` module has been moved to `std::rt::exclusive` and
the type has been rewritten to not internally have an Arc and to have an RAII
guard structure when locking. Old code should stop using `Exclusive` in favor
of the primitives in `libsync`, but if necessary, old code should port to
`Arc<Exclusive<T>>`.
* The local heap has been stripped down to have fewer debugging options. None of
these were tested, and none of these have been used in a very long time.
[breaking-change]
