This commit refactors `std.os.wasi.resolve_preopen` into a (higher-level)
`std.os.wasi.getPreopens` funtion which returns a slice with _all_
preopens at any given time. This fn allows the WASI module to
inquire at any given time for all preopens provided by the runtime.
This commit also makes `cwd()` a compile error on WASI.
This commit adds WASI specific impl of `std.fs.cwd()` in which we
emulate the `cwd` behaviour by inquiring the runtime for a "."
preopen if available. This is OK for simple relative ops, but will
not work for any ops which require absolute paths.
It seems that `std.os.openZ` is too POSIX-specific, so I think it
should not be a point of entry for WASI `open` call. I figure
WASI should be treated as a separate "os" that's _not_ POSIX
especially given the incoming changes in the ephemeral snapshot.
The tests were put into a deadlock, and it seems that darwin doesn't
support `O_SYNC`, though it supports `O_NONBLOCK`. It shouldn't block
even with that, but I'm not sure why else it would fail.
`flock` locks based on the file handle, instead of the process id.
This brings the file locking on unix based systems closer to file
locking on Windows.
This new name (and the fact that it is a function returning a type) will
make it more clear which use cases are better suited for ArrayList and
which are better suited for ArrayListSentineled.
Also for consistency with ArrayList,
* `append` => `appendSlice`
* `appendByte` => `append`
Thanks daurnimator for pointing out the confusion of std.Buffer.
Remove `std.fs.deleteTree`. Callers instead should use
`std.fs.cwd().deleteTree`.
Add `std.fs.deleteTreeAbsolute` for when the caller has an absolute
path.
* remove deprecated `std.fs.Dir` APIs
* `std.fs.Dir.openDir` now takes a options struct with bool fields for
`access_sub_paths` and `iterate`. It's now much more clear how
opening directories works.
* fixed the std lib and various zig code calling the wrong openDir
function.
* the runtime safety check for dir flags is removed in favor of the
cheaper option of putting a comment on the same line as handling
EBADF / ACCESS_DENIED, since that will show up in stack traces.
