rust/src/libstd/rt/rtio.rs, branch try

std: Extract librustrt out of libstd

2014-06-07T05:19:41+00:00

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>`. * 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]

rtio: Remove usage of `Path`

2014-06-07T05:19:41+00:00

The rtio interface is a thin low-level interface over the I/O subsystems, and the `Path` type is a little too high-level for this interface.

rtio: Remove unused stuct

2014-06-07T05:19:41+00:00

std: Improve non-task-based usage

2014-06-04T18:13:12+00:00

A few notable improvements were implemented to cut down on the number of aborts triggered by the standard library when a local task is not found. * Primarily, the unwinding functionality was restructured to support an unsafe top-level function, `try`. This function invokes a closure, capturing any failure which occurs inside of it. The purpose of this function is to be as lightweight of a "try block" as possible for rust, intended for use when the runtime is difficult to set up. This function is *not* meant to be used by normal rust code, nor should it be consider for use with normal rust code. * When invoking spawn(), a `fail!()` is triggered rather than an abort. * When invoking LocalIo::borrow(), which is transitively called by all I/O constructors, None is returned rather than aborting to indicate that there is no local I/O implementation. * Invoking get() on a TLD key will return None if no task is available * Invoking replace() on a TLD key will fail if no task is available. A test case was also added showing the variety of things that you can do without a runtime or task set up now. In general, this is just a refactoring to abort less quickly in the standard library when a local task is not found.

Process::new etc should support non-utf8 commands/args

2014-05-15T05:52:31+00:00

The existing APIs for spawning processes took strings for the command and arguments, but the underlying system may not impose utf8 encoding, so this is overly limiting. The assumption we actually want to make is just that the command and arguments are viewable as [u8] slices with no interior NULLs, i.e., as CStrings. The ToCStr trait is a handy bound for types that meet this requirement (such as &str and Path). However, since the commands and arguments are often a mixture of strings and paths, it would be inconvenient to take a slice with a single T: ToCStr bound. So this patch revamps the process creation API to instead use a builder-style interface, called `Command`, allowing arguments to be added one at a time with differing ToCStr implementations for each. The initial cut of the builder API has some drawbacks that can be addressed once issue #13851 (libstd as a facade) is closed. These are detailed as FIXMEs. Closes #11650. [breaking-change]

io: Implement process wait timeouts

2014-05-14T00:27:42+00:00

This implements set_timeout() for std::io::Process which will affect wait() operations on the process. This follows the same pattern as the rest of the timeouts emerging in std::io::net. The implementation was super easy for everything except libnative on unix (backwards from usual!), which required a good bit of signal handling. There's a doc comment explaining the strategy in libnative. Internally, this also required refactoring the "helper thread" implementation used by libnative to allow for an extra helper thread (not just the timer). This is a breaking change in terms of the io::Process API. It is now possible for wait() to fail, and subsequently wait_with_output(). These two functions now return IoResult due to the fact that they can time out. Additionally, the wait_with_output() function has moved from taking `&mut self` to taking `self`. If a timeout occurs while waiting with output, the semantics are undesirable in almost all cases if attempting to re-wait on the process. Equivalent functionality can still be achieved by dealing with the output handles manually. [breaking-change] cc #13523

Add `stat` method to `std::io::fs::File` to stat without a Path.

2014-05-13T02:52:29+00:00

The `FileStat` struct contained a `path` field, which was filled by the `stat` and `lstat` function. Since this field isn't in fact returned by the operating system (it was copied from the paths passed to the functions) it was removed, as in the `fstat` case we aren't working with a `Path`, but directly with a fd. If your code used the `path` field of `FileStat` you will now have to manually store the path passed to `stat` along with the returned struct. [breaking-change]

core: Remove the cast module

2014-05-11T08:13:02+00:00

This commit revisits the `cast` module in libcore and libstd, and scrutinizes all functions inside of it. The result was to remove the `cast` module entirely, folding all functionality into the `mem` module. Specifically, this is the fate of each function in the `cast` module. * transmute - This function was moved to `mem`, but it is now marked as #[unstable]. This is due to planned changes to the `transmute` function and how it can be invoked (see the #[unstable] comment). For more information, see RFC 5 and #12898 * transmute_copy - This function was moved to `mem`, with clarification that is is not an error to invoke it with T/U that are different sizes, but rather that it is strongly discouraged. This function is now #[stable] * forget - This function was moved to `mem` and marked #[stable] * bump_box_refcount - This function was removed due to the deprecation of managed boxes as well as its questionable utility. * transmute_mut - This function was previously deprecated, and removed as part of this commit. * transmute_mut_unsafe - This function doesn't serve much of a purpose when it can be achieved with an `as` in safe code, so it was removed. * transmute_lifetime - This function was removed because it is likely a strong indication that code is incorrect in the first place. * transmute_mut_lifetime - This function was removed for the same reasons as `transmute_lifetime` * copy_lifetime - This function was moved to `mem`, but it is marked `#[unstable]` now due to the likelihood of being removed in the future if it is found to not be very useful. * copy_mut_lifetime - This function was also moved to `mem`, but had the same treatment as `copy_lifetime`. * copy_lifetime_vec - This function was removed because it is not used today, and its existence is not necessary with DST (copy_lifetime will suffice). In summary, the cast module was stripped down to these functions, and then the functions were moved to the `mem` module. transmute - #[unstable] transmute_copy - #[stable] forget - #[stable] copy_lifetime - #[unstable] copy_mut_lifetime - #[unstable] [breaking-change]

Handle fallout in libnative

2014-05-08T19:06:22+00:00

API Changes: - GetAddrInfoRequest::run() returns Result, ..> - Process::spawn() returns Result(.., Vec<..>), ..>

Handle fallout in io::net::addrinfo, io::process, and rt::rtio

2014-05-08T19:06:22+00:00

API Changes: - get_host_addresses() returns IoResult> - Process.extra_io is Vec>