The translation is fairly direct though it adds some duplication, for example
there are multiple "match" statements that mimic function overloading.
Rust has no overloading, and we cannot have generic methods in the Node trait
(due to a Rust limitation, the error is like "cannot be made into an object")
so we include the type name in method names.
Give clients like "indent_visitor_t" a Rust companion ("IndentVisitor")
that takes care of the AST traversal while the AST consumption remains
in C++ for now. In future, "IndentVisitor" should absorb the entirety of
"indent_visitor_t". This pattern requires that "fish_indent" be exposed
includable header to the CXX bridge.
Alternatively, we could define FFI wrappers for recursive AST traversal.
Rust requires we separate the AST visitors for "mut" and "const"
scenarios. Take this opportunity to concretize both visitors:
The only client that requires mutable access is the populator. To match the
structure of the C++ populator which makes heavy use of function overloading,
we need to add a bunch of functions to the trait. Since there is no other
mutable visit, this seems acceptable.
The "const" visitors never use "will_visit_fields_of()" or
"did_visit_fields_of()", so remove them (though this is debatable).
Like in the C++ implementation, the AST nodes themselves are largely defined
via macros. Union fields like "Statement" and "ArgumentOrRedirection"
do currently not use macros but may in future.
This commit also introduces a precedent for a type that is defined in one
CXX bridge and used in another one - "ParseErrorList". To make this work
we need to manually define "ExternType".
There is one annoyance with CXX: functions that take explicit lifetime
parameters require to be marked as unsafe. This makes little sense
because functions that return `&Foo` with implicit lifetime can be
misused the same way on the C++ side.
One notable change is that we cannot directly port "find_block_open_keyword()"
(which is used to compute an error) because it relies on the stack of visited
nodes. We cannot modify a stack of node references while we do the "mut"
walk. Happily, an idiomatic solution is easy: we can tell the AST visitor
to backtrack to the parent node and create the error there.
Since "node_t::accept_base" is no longer a template we don't need the
"node_visitation_t" trampoline anymore.
The added copying at the FFI boundary makes things slower (memcpy dominates
the profile) but it's not unusable, which is good news:
$ hyperfine ./fish.{old,new}" -c 'source ../share/completions/git.fish'"
Benchmark 1: ./fish.old -c 'source ../share/completions/git.fish'
Time (mean ± σ): 195.5 ms ± 2.9 ms [User: 190.1 ms, System: 4.4 ms]
Range (min … max): 193.2 ms … 205.1 ms 15 runs
Benchmark 2: ./fish.new -c 'source ../share/completions/git.fish'
Time (mean ± σ): 677.5 ms ± 62.0 ms [User: 665.4 ms, System: 10.0 ms]
Range (min … max): 611.7 ms … 805.5 ms 10 runs
Summary
'./fish.old -c 'source ../share/completions/git.fish'' ran
3.47 ± 0.32 times faster than './fish.new -c 'source ../share/completions/git.fish''
Leftovers:
- Enum variants are still snakecase; I didn't get around to changing this yet.
- "ast_type_to_string()" still returns a snakecase name. This could be
changed since it's not user visible.
Keeps the location of original function definition, and also stores
where it was copied. `functions` and `type` show both locations,
instead of none. It also retains the line numbers in the stack trace.
Let's hope this doesn't causes build failures for e.g. musl: I just
know it's good on macOS and our Linux CI.
It's been a long time.
One fix this brings, is I discovered we #include assert.h or cassert
in a lot of places. If those ever happen to be in a file that doesn't
include common.h, or we are before common.h gets included, we're
unawaringly working with the system 'assert' macro again, which
may get disabled for debug builds or at least has different
behavior on crash. We undef 'assert' and redefine it in common.h.
Those were all eliminated, except in one catch-22 spot for
maybe.h: it can't include common.h. A fix might be to
make a fish_assert.h that *usually* common.h exports.
Intern'd strings were intended to be "shared" to reduce memory usage but
this optimization doesn't carry its weight. Remove it. No functional
change expected.
ESCAPE_ALL is not really a helpful name. Also it's the most common flag.
Let's make it the default so we can remove this unhelpful name.
While at it, let's add a default value for the flags argument, which helps
most callers.
The absence of ESCAPE_ALL makes it only escape nonprintable characters
(with some exceptions). We use this for displaying strings in the completion
pager as well as for the human-readable output of "set", "set -S", "bind"
and "functions".
No functional change.
This concerns what happens if the user types e.g. `grep --i` and grep or
its completions have not yet been loaded. Previously we would "bounce to
the main thread" from within the autosuggestion thread to load grep's
completions. However under concurrent execution, this may deadlock as the
main thread is waiting for something else.
In the new implementation, complete simply records the commands that it
would autoload, and returns them back to the caller, where the caller can
decide how to handle them.
In general iothread_perform_on_main risks deadlock under concurrent
execution and we should try to get rid of it.
There should be no user-visible change from this fix.
function_info_t was the "mutable bits" of a function, like its
description. But we have eliminated all of those, so we can eliminate
the class.
No functional change here.
Prior to this change, if you were to type `./fish_indent` it woul dbe
colored as valid, because the path
`$fish_functions_path/./fish_indent.fish` is a real file. However of
course this is not actually executed as a function. Teach
function_exists to return false for function names which are invalid.
Prior to this change, a function with an on-job-exit event handler must be
added with the pgid of the job. But sometimes the pgid of the job is fish
itself (if job control is disabled) and the previous commit made last_pid
an actual pid from the job, instead of its pgroup.
Switch on-job-exit to accept any pid from the job (except fish itself).
This allows it to be used directly with $last_pid, except that it now
works if job control is off. This is implemented by "resolving" the pid to
the internal job id at the point the event handler is added.
Also switch to passing the last pid of the job, rather than its pgroup.
This aligns better with $last_pid.
It is possible to run a function when a process exits via `function
--on-process-exit`, or when a job exits via `function --on-job-exits`.
Internally these were distinguished by the pid in the event: if it was
positive, then it was a process exit. If negative, it represents a pgid
and is a job exit. If zero, it fires for both jobs and processes, which is
pretty weird.
Switch to tracking these explicitly. Separate out the --on-process-exit
and --on-job-exit event types into separate types. Stop negating pgids as
well.
Store the entire function declaration, not just its job list.
This allows us to extract the body of the function complete with any
leading comments and indents.
Fixes#5285
Prior to this fix, fish would attempt to react if a local fish_complete_path
or fish_function_path were set. However this has never been very well tested
and will become impossible with concurrent execution. Always use the global
values.
* Prevent not-yet-loaded functions from loaded when erased
Today, `functions --erase $function` does nothing if the function
hasn't been autoloaded yet.
E.g. run, in an interactive session
> functions --erase ls
> type ls
and be amazed that it still shows our default `ls --color=auto`
wrapper function.
This seems counter-intuitive - removing a function ought to remove it,
whether it had been executed before or not.
* doc/changelog
Prior to this fix, a function_block stored a process_t, which was only used
when printing backtraces. Switch this to an array of arguments, and make
various other cleanups around null terminated argument arrays.
This cleans up how functions are stored and autoloaded. It eliminates the
recursive lock. Instead there is a single normal owning_lock that protects
the entirety of the function data. Autoloading is re-implemented via the
new autoloader_t.
