This can be used when you primarily want to return a reference but in order for
that reference to live long enough it must be returned with an object.
i.e. given `Mutex<Foo { bar }>` you want a function to lock the mutex and return
a reference to `bar` but you can't return that reference since it has a lifetime
dependency on `MutexGuard` (which only derefs to all of `Foo` and not just
`bar`). You can return a `Projection` owning the `MutexGuard<Foo>` and set it up
to deref to `&bar`.
This ports some signal setup and handling bits to Rust.
The signal handling machinery requires walking over the list of known signals;
that's not supported by the Signal type. Rather than duplicate the list of
signals yet again, switch back to a table, as we had in C++.
This also adds two further pieces which were neglected by the Signal struct:
1. Localize signal descriptions
2. Support for integers as the signal name
Like the WSL check, this was incorrectly assuming WSL implies
cfg(windows) when it's actually picked up as Linux.
Also, improve over the C++ code by not relying on the build-time WSL
status to determine if we are running on WSL at runtime since it's often
the case that the fish binaries are built on a non-WSL host (for
packaging) then executed on a WSL only at runtime.
(But it's ok to assume if fish has been built for Windows or not Linux
that it will either be run or not run on top of a Win32 character device
system.)
Also, port of the comment and relevant WSL and fish issue links over
from the CPP codebase for posterity.
* Since we already have an allocation of length wstr.len(), it's
probably better to allocate the result (which is strictly less than or
equal to the input length) up-front rather than risk thrashing the Vec
allocation,
* There's no need to compare c2 against '\0' since that will just cause
to_digit(16) to return None anyway,
* Our convert_hex() specialization of to_digit(16) that only checks
capital letters A-F without also checking lowercase a-f isn't
significantly faster than just use to_digit(16), and we already assert
that the input *wasn't* a lowercase a-f before making the call, so
there's no point in using a special function to handle that.
This reverts commit 76dc849fca.
The warning added in that commit is incorrect. The functions
unescape_string_url and unescape_string_var will not panic, because
char_at() return 0 if the index is equal to its length.
This reverts commit f9c92753c4.
This commit attempted to replace exit_without_destructors() with
std::process::exit; however this is wrong for two reasons:
1. std::process::exit() runs Rust runtime cleanup stuff we don't want
2. std::process::exit() invokes destructors, meaning atexit handlers,
which we don't want.
The type system no longer guarantees that the input string is nul-terminated,
meaning accessing beyond the range-checked `i` a char-at-a-time is no longer
safe. (In C++, we would either be using a plain C string which is always
nul-terminated or we would be using (w)string::cstr() which similarly grants
access to its nul-terminated buffer.)
Aside from that, there's no need to explicitly check `if c2 == '\0'` because
'\0' is not a valid hex digit so the `?` tacked on to `convert_hex_digit(c2)?`
will abort and return `None` anyway.
convert_hex_digit() is not appreciably faster than char::to_digit(16) and makes
the code less maintainable since it encodes certain assumptions; since it's also
not used consistently just drop it in favor of the std fn.
Since the output string (per the decode logic) is always shorter than or equal
to the input string, just reserve the input string size upfront to prevent vec
reallocations.
Somewhat counter-intuitively, this code is active when compiling under *Linux*
and is always false when compiling under Windows. The logic was incorrectly
reversed before (it's easier to reason about when you realize that fish doesn't
even compile under Windows because it uses tons of libc functions).
As the code was actually never compiled, it wasn't actually tested for validity
either and there were some issues that prevented it from compiling that have
since been fixed. The logic has also been adjusted a bit to make it possible to
use the rust-native int parsing instead of `libc::strtod()`.
The code has been changed to use `once_cell::race::OnceBool` instead of
`once_cell::sync::Lazy<T>` which imposes a greater runtime burden with locking
and other overhead. We don't care if the code runs more than once on init (if
calls were to race, though they probably don't) - just that the code isn't
subsequently executed on each call. The `once_cell::race` module is a better fit
here, though it doesn't expose the ergonomic `Lazy<T>` façade around its types.
is_main_thread() and co were previously ported to threads.rs, so remove the
duplicate code and move everything else related to threads there as well. No
need for common.rs to be as long as our old common.cpp!
I left #[deprecated] stubs in common.rs to help redirect anyone porting code
over that we can remove after the port has finished.
Additionally, the fork guards had previously been left as a todo!() item but I
ported that over. They're all called from the now-central threads::init()
function so there isn't a need to call each individual thread-management-fn
manually.
The decision was made a while back to try and embrace/use the native rust thread
functionality and utilities so the manual thread management code has been ripped
out and was replaced with code that marshals the native rust values instead. The
values won't line up with what the C++ code sees, but it never lined up anyway
since each was using a separate counter to keep track of the values.
This caused math to assert out because it never wrote into the buffer.
Now, presumably it wrote somewhere but I don't know where, so fixing
this seems like a good idea.
Fixes#9735.
This allows us to use the scoped push in more scenarios by appeasing the
borrow checker.
Use it in a couple of places instead of ScopeGuard. Hopefully this is makes
porting easier.
Even though we generally dont' want to use this type (because it's immutable),
it can be advantageous when working with the std::fs API. This is because
it implements "AsRef<Path>" which neither of CString and Vec<u8> do.
Most of it is duplicated, hence untested.
Functions like mbrtowc are not exposed by the libc crate, so declare them
ourselves.
Since we don't know the definition of C macros, add two big hacks to make
this work:
1. Replace MB_LEN_MAX and mbstate_t with values (resp types) that should
be large enough for any implementation.
2. Detect the definition of MB_CUR_MAX in the build script. This requires
more changes for each new libc. We could also use this approach for 1.
Additionally, this commit brings a small behavior change to
read_unquoted_escape(): we cannot decode surrogate code points like \UDE01
into a Rust char, so use � (\UFFFD, replacement character) instead.
Previously, we added such code points to a wcstring; looks like they were
ignored when printed.
Due to limitations imposed by the borrow checker, there are very few places
where we will be able to use the `ScopedPush` class ported over from the C++
codebase (once you capture the value w/ a `ScopedPush` you can't access the
value - or the mutable reference you used to reach it! - until the `ScopedPush`
object goes out of scope).
This alternative requires binding the previous values to a variable and manually
restoring them in the callback passed to the `ScopeGuard` constructor, but will
work with rust's borrow and `&mut` paradigm.
wchar.rs should not import let alone reexport FFI strings.
Stop re-exporting utf32str! because we use L! instead.
In wchar_ffi.rs, stop re-exporting cxx::CxxWString because that hasn't
seen adoption.
I think we should use re-exports only for aliases like "wstr" or for aliases
into internal modules.
So I'd probably remove `pub use wchar_ffi::wcharz_t = crate::ffi::wcharz_t`
as well.
The existing code is kept, but a rusty version of these functions is added for
code that needs them.
These should only be temporarily used when porting 1-to-1 from C++; we should
use the std library's `read()` and `write_all()` methods instead in the future.
By extracting the equivalent of i32::cmp() into its own const function,
it becomes a lot easier to see what is happening and the logic can be
more direct.
More ugliness with types that cxx bridge can't recognize as being POD. Using
pointers to get/set `termios` values with an assert to make sure we're using
identical definitions on both sides (in cpp from the system headers and in rust
from the libc crate as exported).
I don't know why cxx bridge doesn't allow `SharedPtr<OpaqueRustType>` but we can
work around it in C++ by converting a `Box<T>` to a `shared_ptr<T>` then convert
it back when it needs to be destructed. I can't find a clean way of doing it
from the cxx bridge wrapper so for now it needs to be done manually in the C++
code.
Types/values that are drop-in ready over ffi are renamed to match the old cpp
names but for types that now differ due to ffi difficulties I've left the `_ffi`
in the function names to indicate that this isn't the "correct" way of using the
types/methods.
Rust doesn't have __FUNCTION__ or __func__ (though you can hack around it with a
proc macro, but that will require a separate crate and slowing down compilation
times with heavy proc macro dependencies), so these are just regular functions
(at least for now). Rust's default stack trace on panic (even in release mode)
should be enough (and the functions themselves are inlined so the calling
function should be the second frame from the top, after the #[cold] panic
functions).
