Previously on Windows a directory junction would return false from `is_dir`,
causing various odd behavior, specifically calls to `create_dir_all` might fail
when they would otherwise continue to succeed.
Closes#26716
This makes `Debug` for `File` show the file path and access mode of the file on OS X, just like on Linux.
I'd be happy about any feedback how to make this code better. In particular, I'm not sure how to handle the buffer passed to `fnctl`. This way works, but it feels a bit cumbersome. `fcntl` unfortunately doesn't return the length of the path.
Previously on Windows a directory junction would return false from `is_dir`,
causing various odd behavior, specifically calls to `create_dir_all` might fail
when they would otherwise continue to succeed.
Closes#26716
This allows CString and CStr to be used with the Cow type,
which is extremely useful when interfacing with C libraries
that make extensive use of C-style strings.
This allows CString and CStr to be used with the Cow type,
which is extremely useful when interfacing with C libraries
that make extensive use of C-style strings.
I find that isn't supported on the current API and I think is necesary.
It is my first PR to rust (I'm not a rust expert and I'm not sure if this is the better way to propose this thinks), of course any suggestion of change will be welcome.
I'm almost sure that in windows aren't supported this filetypes, then, i put in the api of win::fs the functions with a fixed false in the response, I hope this is correct.
In a followup to PR #26849, improve one more location for I/O where
we can use `Vec::resize` to ensure better performance when zeroing
buffers.
Use the `vec![elt; n]` macro everywhere we can in the tree. It replaces
`repeat(elt).take(n).collect()` which is more verbose, requires type
hints, and right now produces worse code. `vec![]` is preferable for vector
initialization.
The `vec![]` replacement touches upon one I/O path too, Stdin::read
for windows, and that should be a small improvement.
r? @alexcrichton
The common pattern `iter::repeat(elt).take(n).collect::<Vec<_>>()` is
exactly equivalent to `vec![elt; n]`, do this replacement in the whole
tree.
(Actually, vec![] is smart enough to only call clone n - 1 times, while
the former solution would call clone n times, and this fact is
virtually irrelevant in practice.)
Improve zerofill in Vec::resize and Read::read_to_end
We needed a more efficient way to zerofill the vector in read_to_end.
This to reduce the memory intialization overhead to a minimum.
Use the implementation of `std::vec::from_elem` (used for the vec![]
macro) for Vec::resize as well. For simple element types like u8, this
compiles to memset, so it makes Vec::resize much more efficient.
Use the vec![] macro directly to create a sized, zeroed vector.
This should result in a big speedup when creating BufReader, because
vec![0; cap] compiles to a memset call, while the previous extend code
currently did not.
We needed a more efficient way to zerofill the vector in read_to_end.
This to reduce the memory intialization overhead to a minimum.
Use the implementation of `std::vec::from_elem` (used for the vec![]
macro) for Vec::resize as well. For simple element types like u8, this
compiles to memset, so it makes Vec::resize much more efficient.
This PR was originally going to be a "let's start running tests on MSVC" PR, but it didn't quite get to that point. It instead gets us ~80% of the way there! The steps taken in this PR are:
* Landing pads are turned on by default for 64-bit MSVC. The LLVM support is "good enough" with the caveat the destructor glue is now marked noinline. This was recommended [on the associated bug](https://llvm.org/bugs/show_bug.cgi?id=23884) as a stopgap until LLVM has a better representation for exception handling in MSVC. The consequence of this is that MSVC will have a bit of a perf hit, but there are possible routes we can take if this workaround sticks around for too long.
* The linker (`link.exe`) is now looked up in the Windows Registry if it's not otherwise available in the environment. This improves using the compiler outside of a VS shell (e.g. in a MSYS shell or in a vanilla cmd.exe shell). This also makes cross compiles via Cargo "just work" when crossing between 32 and 64 bit!
* TLS destructors were fixed to start running on MSVC (they previously weren't running at all)
* A few assorted `run-pass` tests were fixed.
* The dependency on the `rust_builtin` library was removed entirely for MSVC to try to prevent any `cl.exe` compiled objects get into the standard library. This should help us later remove any dependence on the CRT by the standard library.
* I re-added `rust_try_msvc_32.ll` for 32-bit MSVC and ensured that landing pads were turned off by default there as well.
Despite landing pads being enabled, there are still *many* failing tests on MSVC. The two major classes I've identified so far are:
* Spurious aborts. It appears that when optimizations are enabled that landing pads aren't always lined up properly, and sometimes an exception being thrown can't find the catch block down the stack, causing the program to abort. I've been working to reduce this test case but haven't been met with great success just yet.
* Parallel codegen does not work on MSVC. Our current strategy is to take the N object files emitted by the N codegen threads and use `ld -r` to assemble them into *one* object file. The MSVC linker, however, does not have this ability, and this will need to be rearchitected to work on MSVC.
I will fix parallel codegen in a future PR, and I'll also be watching LLVM closely to see if the aborts... disappear!
This library has no shims which are actually needed on Windows now, so translate
that last easy one into Rust and then don't link it at all on Windows.
This was added after Windows 7 SP1, so it's not always available. Instead use
the `SetHandleInformation` function to flag a socket as not inheritable. This is
not atomic with respect to creating new processes, but it mirrors what Unix does
with respect to possibly using the atomic option in the future.
Closes#26543
Just like the original article our Windows TLS support is based on predicted,
this symbol must be linked in on MSVC to pull in the necessary support for TLS
variables. This commit fixes a number of unit tests which require that TLS
destructors are run.
This was added after Windows 7 SP1, so it's not always available. Instead use
the `SetHandleInformation` function to flag a socket as not inheritable. This is
not atomic with respect to creating new processes, but it mirrors what Unix does
with respect to possibly using the atomic option in the future.
Closes#26543
Setting append without write doesn't give you a writeable file. Showing
it as an example in the docs is confusing at best.
Using truncate on a read-only file is an error on POSIX systems (note
however that using create with read-only flags is fine).
This commit enables executables linked against the standard library to run on
Windows XP. There are two main components of this commit:
* APIs not available on XP are shimmed to have a fallback implementation and use
runtime detection to determine if they are available.
* Mutexes on Windows were reimplemented to use critical sections on XP where
rwlocks are not available.
The APIs which are not available on XP are:
* SetFileInformationByHandle - this is just used by `File::truncate` and that
function just returns an error now.
* SetThreadStackGuarantee - this is used by the stack overflow support on
windows, but if this isn't available then it's just ignored (it seems
non-critical).
* All condition variable APIs are missing - the shims added for these apis
simply always panic for now. We may eventually provide a fallback
implementation, but for now the standard library does not rely on condition
variables for normal use.
* RWLocks, like condition variables, are missing entirely. The same story for
condition variables is taken here. These APIs are all now panicking stubs as
the standard library doesn't rely on RWLocks for normal use.
Currently, as an optimization, we use SRWLOCKs for the standard `sync::Mutex`
implementation on Windows, which is indeed required for normal operation of the
standard library. To allow the standard library to run on XP, this commit
reimplements mutexes on Windows to use SRWLOCK instances *if available* and
otherwise a CriticalSection is used (with some checking for recursive
locking).
With all these changes put together, a 32-bit MSVC-built executable can run on
Windows XP and print "hello world"
Closes#12842Closes#19992Closes#24776
It turns out that the 32-bit toolchain for MSVC has many of these functions as
`static inline` functions in header files so there's not actually a symbol for
Rust to call. All of the implementations just cast floats to their 64-bit
variants and then cast back to 32-bit at the end, so the standard library now
takes this strategy.
Now that LLVM has been updated, the only remaining roadblock to implementing
unwinding for MSVC is to fill out the runtime support in `std::rt::unwind::seh`.
This commit does precisely that, fixing up some other bits and pieces along the
way:
* The `seh` unwinding module now uses `RaiseException` to initiate a panic.
* The `rust_try.ll` file was rewritten for MSVC (as it's quite different) and is
located at `rust_try_msvc_64.ll`, only included on MSVC builds for now.
* The personality function for all landing pads generated by LLVM is hard-wired
to `__C_specific_handler` instead of the standard `rust_eh_personality` lang
item. This is required to get LLVM to emit SEH unwinding information instead
of DWARF unwinding information. This also means that on MSVC the
`rust_eh_personality` function is entirely unused (but is defined as it's a
lang item).
More details about how panicking works on SEH can be found in the
`rust_try_msvc_64.ll` or `seh.rs` files, but I'm always open to adding more
comments!
A key aspect of this PR is missing, however, which is that **unwinding is still
turned off by default for MSVC**. There is a [bug in llvm][llvm-bug] which
causes optimizations to inline enough landing pads that LLVM chokes. If the
compiler is optimized at `-O1` (where inlining isn't enabled) then it can
bootstrap with unwinding enabled, but when optimized at `-O2` (inlining is
enabled) then it hits a fatal LLVM error.
[llvm-bug]: https://llvm.org/bugs/show_bug.cgi?id=23884
This removes a footgun, since it is a reasonable assumption to make that
pointers to `T` will be aligned to `align_of::<T>()`. This also matches
the behaviour of C/C++. `min_align_of` is now deprecated.
Closes#21611.
Now that LLVM has been updated, the only remaining roadblock to implementing
unwinding for MSVC is to fill out the runtime support in `std::rt::unwind::seh`.
This commit does precisely that, fixing up some other bits and pieces along the
way:
* The `seh` unwinding module now uses `RaiseException` to initiate a panic.
* The `rust_try.ll` file was rewritten for MSVC (as it's quite different) and is
located at `rust_try_msvc_64.ll`, only included on MSVC builds for now.
* The personality function for all landing pads generated by LLVM is hard-wired
to `__C_specific_handler` instead of the standard `rust_eh_personality` lang
item. This is required to get LLVM to emit SEH unwinding information instead
of DWARF unwinding information. This also means that on MSVC the
`rust_eh_personality` function is entirely unused (but is defined as it's a
lang item).
More details about how panicking works on SEH can be found in the
`rust_try_msvc_64.ll` or `seh.rs` files, but I'm always open to adding more
comments!
A key aspect of this PR is missing, however, which is that **unwinding is still
turned off by default for MSVC**. There is a [bug in llvm][llvm-bug] which
causes optimizations to inline enough landing pads that LLVM chokes. If the
compiler is optimized at `-O1` (where inlining isn't enabled) then it can
bootstrap with unwinding enabled, but when optimized at `-O2` (inlining is
enabled) then it hits a fatal LLVM error.
[llvm-bug]: https://llvm.org/bugs/show_bug.cgi?id=23884
This removes a footgun, since it is a reasonable assumption to make that
pointers to `T` will be aligned to `align_of::<T>()`. This also matches
the behaviour of C/C++. `min_align_of` is now deprecated.
Closes#21611.
signal(), sigemptyset(), and sigaddset() are only available as inline
functions until Android API 21. liblibc already handles signal()
appropriately, so drop it from c.rs; translate sigemptyset() and
sigaddset() (which is only used in a test) by hand from the C inlines.
We probably want to revert this commit when we bump Android API level.
Make sure that child processes don't get affected by libstd's desire to
ignore SIGPIPE, nor a third-party library's signal mask (which is needed
to use either a signal-handling thread correctly or to use signalfd /
kqueue correctly).
Both c.rs and stack_overflow.rs had bindings of libc's signal-handling
routines. It looks like the split dated from #16388, when (what is now)
c.rs was in libnative but not libgreen. Nobody is currently using the
c.rs bindings, but they're a bit more accurate in some places.
Move everything to c.rs (since I'll need signal handling in process.rs,
and we should avoid duplication), clean up the bindings, and manually
double-check everything against the relevant system headers (fixing a
few things in the process).
It looks like a lot of this dated to previous incarnations of the io
module, etc., and went unused in the reworking leading up to 1.0. Remove
everything we're not actively using (except for signal handling, which
will be reworked in the next commit).
The `execv` family of functions and `getopt` are prototyped somewhat strangely in C: they take a `char *const argv[]` (and `envp`, for `execve`), an immutable array of mutable C strings -- in other words, a `char *const *argv` or `argv: *const *mut c_char`. The current Rust binding uses `*mut *const c_char`, which is backwards (a mutable array of constant C strings).
That said, these functions do not actually modify their arguments. Once upon a time, C didn't have `const`, and to this day, string literals in C have type `char *` (`*mut c_char`). So an array of string literals has type `char * []`, equivalent to `char **` in a function parameter (Rust `*mut *mut c_char`). C allows an implicit cast from `T **` to `T * const *` (`*const *mut T`) but not to `const T * const *` (`*const *const T`). Therefore, prototyping `execv` as taking `const char * const argv[]` would have broken existing code (by requiring an explicit cast), despite being more correct. So, even though these functions don't need mutable data, they're prototyped as if they do.
While it's theoretically possible that an implementation could choose to use its freedom to modify the mutable data, such an implementation would break the innumerable users of `execv`-family functions that call them with string literals. Such an implementation would also break `std::process`, which currently works around this with an unsafe `as *mut _` cast, and assumes that `execvp` secretly does not modify its argument. Furthermore, there's nothing useful to be gained by being able to write to the strings in `argv` themselves but not being able to write to the array containing those strings (you can't reorder arguments, add arguments, increase the length of any parameter, etc.).
So, despite the C prototype with its legacy C problems, it's simpler for everyone for Rust to consider these functions as taking `*const *const c_char`, and it's also safe to do so. Rust does not need to expose the mistakes of C here. This patch makes that change, and drops the unsafe cast in `std::process` since it's now unnecessary.
The documentation of `std::net::Shutdown` mentions says it can be passed to the `shutdown` method of `UdpSocket`, which isn't true because `UdpSocket` has no such method. This commit removes that mention.
Fixes https://github.com/rust-lang/rust/issues/26408
Example output when using `Result::unwrap`:
```
thread '<main>' panicked at 'called `Result::unwrap()` on an `Err` value: Error { repr: Os { code: 2, message: "The system cannot find the file specified.\r\n" } }', src/libcore\result.rs:731
```
This could technically be considered a breaking change for any code that depends on the format of the `Debug` output for `io::Error` but I sincerely hope nobody wrote code like that.
The execv family of functions do not modify their arguments, so they do
not need mutable pointers. The C prototypes take a constant array of
mutable C-strings, but that's a legacy quirk from before C had const
(since C string literals have type `char *`). The Rust prototypes had
`*mut` in the wrong place, anyway: to match the C prototypes, it should
have been `*const *mut c_char`. But it is safe to pass constant strings
(like string literals) to these functions.
getopt is a special case, since GNU getopt modifies its arguments
despite the `const` claim in the prototype. It is apparently only
well-defined to call getopt on the actual argc and argv parameters
passed to main, anyway. Change it to take `*mut *mut c_char` for an
attempt at safety, but probably nobody should be using it from Rust,
since there's no great way to get at the parameters as passed to main.
Also fix the one caller of execvp in libstd, which now no longer needs
an unsafe cast.
Fixes#16290.
This commit shards the all-encompassing `core`, `std_misc`, `collections`, and `alloc` features into finer-grained components that are much more easily opted into and tracked. This reflects the effort to push forward current unstable APIs to either stabilization or removal. Keeping track of unstable features on a much more fine-grained basis will enable the library subteam to quickly analyze a feature and help prioritize internally about what APIs should be stabilized.
A few assorted APIs were deprecated along the way, but otherwise this change is just changing the feature name associated with each API. Soon we will have a dashboard for keeping track of all the unstable APIs in the standard library, and I'll also start making issues for each unstable API after performing a first-pass for stabilization.
The `thread::scoped` function will never be stabilized as-is and the API will
likely change significantly if it does, so this function is deprecated for
removal.
This function follows the well-established "constructor" pattern and the
initialization constant will likely be deprecated in favor of it once `const_fn`
is stabilized.
This commit shards the broad `core` feature of the libcore library into finer
grained features. This split groups together similar APIs and enables tracking
each API separately, giving a better sense of where each feature is within the
stabilization process.
A few minor APIs were deprecated along the way:
* Iterator::reverse_in_place
* marker::NoCopy
Currently the compiler has no knowledge of `#[thread_local]` which forces users
to take on two burdens of unsafety:
* The lifetime of the borrow of a `#[thread_local]` static is **not** `'static`
* Types in `static`s are required to be `Sync`
The thread-local modules mostly curb these facets of unsafety by only allowing
very limited scopes of borrows as well as allowing all types to be stored in a
thread-local key (regardless of whether they are `Sync`) through an `unsafe
impl`.
Unfortunately these measures have the consequence of being able to take the
address of the key itself and send it to another thread, allowing the same key
to be accessed from two different threads. This is clearly unsafe, and this
commit fixes this problem with the same trick used by `LocalKey`, which is to
have an indirect function call to find the address of the *current thread's*
thread local. This way the address of thread local keys can safely be sent among
threads as their lifetime truly is `'static`.
This commit will reduce the performance of cross-crate scoped thread locals as
it now requires an indirect function call, but this can likely be overcome in a
future commit.
Closes#25894
Closes#25977
The various `stdfoo_raw` methods in std::io now return `io::Result`s,
since they may not exist on Windows. They will always return `Ok` on
Unix-like platforms.
[breaking-change]
Closes#25977
The various `stdfoo_raw` methods in std::io now return `io::Result`s,
since they may not exist on Windows. They will always return `Ok` on
Unix-like platforms.
[breaking-change]
This commit stabilizes the following APIs, slating them all to be cherry-picked
into the 1.1 release.
* fs::FileType (and transitively the derived trait implementations)
* fs::Metadata::file_type
* fs::FileType::is_dir
* fs::FileType::is_file
* fs::FileType::is_symlink
* fs::DirEntry::metadata
* fs::DirEntry::file_type
* fs::DirEntry::file_name
* fs::set_permissions
* fs::symlink_metadata
* os::raw::{self, *}
* os::{android, bitrig, linux, ...}::raw::{self, *}
* os::{android, bitrig, linux, ...}::fs::MetadataExt
* os::{android, bitrig, linux, ...}::fs::MetadataExt::as_raw_stat
* os::unix::fs::PermissionsExt
* os::unix::fs::PermissionsExt::mode
* os::unix::fs::PermissionsExt::set_mode
* os::unix::fs::PermissionsExt::from_mode
* os::unix::fs::OpenOptionsExt
* os::unix::fs::OpenOptionsExt::mode
* os::unix::fs::DirEntryExt
* os::unix::fs::DirEntryExt::ino
* os::windows::fs::MetadataExt
* os::windows::fs::MetadataExt::file_attributes
* os::windows::fs::MetadataExt::creation_time
* os::windows::fs::MetadataExt::last_access_time
* os::windows::fs::MetadataExt::last_write_time
* os::windows::fs::MetadataExt::file_size
The `os::unix::fs::Metadata` structure was also removed entirely, moving all of
its associated methods into the `os::unix::fs::MetadataExt` trait instead. The
methods are all marked as `#[stable]` still.
As some minor cleanup, some deprecated and unstable fs apis were also removed:
* File::path
* Metadata::accessed
* Metadata::modified
Features that were explicitly left unstable include:
* fs::WalkDir - the semantics of this were not considered in the recent fs
expansion RFC.
* fs::DirBuilder - it's still not 100% clear if the naming is right here and if
the set of functionality exposed is appropriate.
* fs::canonicalize - the implementation on Windows here is specifically in
question as it always returns a verbatim path. Additionally the Unix
implementation is susceptible to buffer overflows on long paths unfortunately.
* fs::PathExt - as this is just a convenience trait, it is not stabilized at
this time.
* fs::set_file_times - this funciton is still waiting on a time abstraction.
* Slate these features to be stable in 1.2 instead of 1.1 (not being backported)
* Have the `FromRawFd` implementations follow the contract of the `FromRawFd`
trait by taking ownership of the primitive specified.
* Refactor the implementations slightly to remove the `unreachable!` blocks as
well as separating the stdio representation of `std::process` from
`std::sys::process`.
cc #25494
As far as I was able to determine, it's currently *impossible* to allocate a C NUL-terminated string in Rust and then return it to C (transferring ownership), without leaking memory. There is support for passing the string to C (borrowing).
To complicate matters, it's not possible for the C code to just call `free` on the allocated string, due to the different allocators in use.
`CString` has no way to recreate itself from a pointer. This commit adds one. This is complicated a bit because Rust `Vec`s want the pointer, size, and capacity.
To deal with that, another method to shrink and "leak" the `CString` to a `char *` is also provided.
We can then use `strlen` to determine the length of the string, which must match the capacity.
**TODO**
- [x] Improve documentation
- [x] Add stability markers
- [x] Convert to `Box<[u8]>`
### Example code
With this example code:
```rust
#![feature(libc)]
#![feature(cstr_to_str)]
#![feature(c_str_memory)]
extern crate libc;
use std::ffi::{CStr,CString};
#[no_mangle]
pub extern fn reverse(s: *const libc::c_char) -> *const libc::c_char {
let s = unsafe { CStr::from_ptr(s) };
let s2 = s.to_str().unwrap();
let s3: String = s2.chars().rev().collect();
let s4 = CString::new(s3).unwrap();
s4.into_ptr()
}
#[no_mangle]
pub extern fn cleanup(s: *const libc::c_char) {
unsafe { CString::from_ptr(s) };
}
```
Compiled using `rustc --crate-type dylib str.rs`, I was able to link against it from C (`gcc -L. -l str str.c -o str`):
```c
#include <stdio.h>
extern char *reverse(char *);
extern void cleanup(char *);
int main() {
char *s = reverse("Hello, world!");
printf("%s\n", s);
cleanup(s);
}
```
As well as dynamically link via Ruby:
```ruby
require 'fiddle'
require 'fiddle/import'
module LibSum
extend Fiddle::Importer
dlload './libstr.dylib'
extern 'char* reverse(char *)'
extern 'void cleanup(char *)'
end
s = LibSum.reverse("hello, world!")
puts s
LibSum.cleanup(s)
```
* Slate these features to be stable in 1.2 instead of 1.1 (not being backported)
* Have the `FromRawFd` implementations follow the contract of the `FromRawFd`
trait by taking ownership of the primitive specified.
* Refactor the implementations slightly to remove the `unreachable!` blocks as
well as separating the stdio representation of `std::process` from
`std::sys::process`.
This commit stabilizes the following APIs, slating them all to be cherry-picked
into the 1.1 release.
* fs::FileType (and transitively the derived trait implementations)
* fs::Metadata::file_type
* fs::FileType::is_dir
* fs::FileType::is_file
* fs::FileType::is_symlink
* fs::DirEntry::metadata
* fs::DirEntry::file_type
* fs::DirEntry::file_name
* fs::set_permissions
* fs::symlink_metadata
* os::raw::{self, *}
* os::{android, bitrig, linux, ...}::raw::{self, *}
* os::{android, bitrig, linux, ...}::fs::MetadataExt
* os::{android, bitrig, linux, ...}::fs::MetadataExt::as_raw_stat
* os::unix::fs::PermissionsExt
* os::unix::fs::PermissionsExt::mode
* os::unix::fs::PermissionsExt::set_mode
* os::unix::fs::PermissionsExt::from_mode
* os::unix::fs::OpenOptionsExt
* os::unix::fs::OpenOptionsExt::mode
* os::unix::fs::DirEntryExt
* os::unix::fs::DirEntryExt::ino
* os::windows::fs::MetadataExt
* os::windows::fs::MetadataExt::file_attributes
* os::windows::fs::MetadataExt::creation_time
* os::windows::fs::MetadataExt::last_access_time
* os::windows::fs::MetadataExt::last_write_time
* os::windows::fs::MetadataExt::file_size
The `os::unix::fs::Metadata` structure was also removed entirely, moving all of
its associated methods into the `os::unix::fs::MetadataExt` trait instead. The
methods are all marked as `#[stable]` still.
As some minor cleanup, some deprecated and unstable fs apis were also removed:
* File::path
* Metadata::accessed
* Metadata::modified
Features that were explicitly left unstable include:
* fs::WalkDir - the semantics of this were not considered in the recent fs
expansion RFC.
* fs::DirBuilder - it's still not 100% clear if the naming is right here and if
the set of functionality exposed is appropriate.
* fs::canonicalize - the implementation on Windows here is specifically in
question as it always returns a verbatim path. Additionally the Unix
implementation is susceptible to buffer overflows on long paths unfortunately.
* fs::PathExt - as this is just a convenience trait, it is not stabilized at
this time.
* fs::set_file_times - this funciton is still waiting on a time abstraction.
With the latter is provided by the `From` conversion trait, the former is now completely redundant. Their code is identical. Let’s deprecate now and plan to remove in the next cycle. (It’s `#[unstable]`.)
r? @alexcrichton
CC @nagisa
The API documentation is not explicit enough that because `try!` returns
`Err` early for you, you can only use it in functions that return
`Result`. The book mentions this, but if you come across `try!` outside
of the book and look it up in the docs, this restriction on the return
type of the function is not particularly clear.
I seriously had this epiphany a few days ago after working with Rust for MONTHS, and after seeing [a friend have to come to the same realization](http://joelmccracken.github.io/entries/a-simple-web-app-in-rust-pt-2a/), I'd like to save more people from this confusion :) 💖
The API documentation is not explicit enough that because `try!` returns
`Err` early for you, you can only use it in functions that return
`Result`. The book mentions this, but if you come across `try!` outside
of the book and look it up in the docs, this restriction on the return
type of the function is not particularly clear.
These are implemented in asm, they're just not inlined.
Open questions are:
* Should I just inline them? They're.. big, but it seems as though this needs violates the #[inline(always)] gaurantees the others make.
* Does something (llvm?) provide these as intrinsics? The structure of this code suggests that we could be hoisting off something else, instead of flagrantly ignoring it like we do for power and mips.
This takes the cases from `InvalidInput` where a data format error
was encountered. This is different from the documented semantics
of `InvalidInput`, which more likely indicate a programming error.
Fixesrust-lang/rfcs#906
Currently the compiler has no knowledge of `#[thread_local]` which forces users
to take on two burdens of unsafety:
* The lifetime of the borrow of a `#[thread_local]` static is **not** `'static`
* Types in `static`s are required to be `Sync`
The thread-local modules mostly curb these facets of unsafety by only allowing
very limited scopes of borrows as well as allowing all types to be stored in a
thread-local key (regardless of whether they are `Sync`) through an `unsafe
impl`.
Unfortunately these measures have the consequence of being able to take the
address of the key itself and send it to another thread, allowing the same key
to be accessed from two different threads. This is clearly unsafe, and this
commit fixes this problem with the same trick used by `LocalKey`, which is to
have an indirect function call to find the address of the *current thread's*
thread local. This way the address of thread local keys can safely be sent among
threads as their lifetime truly is `'static`.
This commit will reduce the performance of cross-crate scoped thread locals as
it now requires an indirect function call, but this can likely be overcome in a
future commit.
Closes#25894
This commit adds a ./configure option called `--disable-elf-tls` which disables
ELF based TLS (that which is communicated to LLVM) on platforms which already
support it. OSX 10.6 does not support this form of TLS, and some users of Rust
need to target 10.6 and are unable to do so due to the usage of TLS. The
standard library will continue to use ELF based TLS on OSX by default (as the
officially supported platform is 10.7+), but this adds an option to compile the
standard library in a way that is compatible with 10.6.
Closes#25342
The `HashMap` and `HashSet` iterators use `RawTable::first_bucket_raw` which is generic and will get inlined cross-crate.
However, `first_bucket_raw` calls `calculate_offsets` and the call doesn't get inlined, despite being a simple function.
This missing `#[inline]` results in `hash_table::calculate_offsets` showing up at the top of a callgrind profile with 3 million calls (for the testcase in #25916).
This commit implements a number of standard traits for the standard library's
process I/O handles. The `FromRaw{Fd,Handle}` traits are now implemented for the
`Stdio` type and the `AsRaw{Fd,Handle}` traits are now implemented for the
`Child{Stdout,Stdin,Stderr}` types.
The stability markers for these implementations mention that they are stable for
1.1 as I will nominate this commit for cherry-picking to beta.
This takes the cases from InvalidInput where a data format error
was encountered. This is different from the documented semantics
of InvalidInput, which more likely indicate a programming error.
The first commit simply forwards `io::Error`'s `cause` implementation to the inner error.
The second commit adds accessor methods for the inner error. Method names mirror those used elsewhere like `BufReader`.
r? @alexcrichton
This commit adds a ./configure option called `--disable-elf-tls` which disables
ELF based TLS (that which is communicated to LLVM) on platforms which already
support it. OSX 10.6 does not support this form of TLS, and some users of Rust
need to target 10.6 and are unable to do so due to the usage of TLS. The
standard library will continue to use ELF based TLS on OSX by default (as the
officially supported platform is 10.7+), but this adds an option to compile the
standard library in a way that is compatible with 10.6.
