env_scoped_t lives between environment_t and env_stack_t.
It represents the read-only logic of env_stack_t and will be used to back
the new environment snapshot implementation.
Prior to this change, fish used a global flag to decide if we should check
for changes to universal variables. This flag was then checked at arbitrary
locations, potentially triggering variable updates and event handlers for
those updates; this was very hard to reason about.
Switch to triggering a universal variable update at a fixed location,
after running an external command. The common case is that the variable
file has not changed, which we can identify with just a stat() call, so
this is pretty cheap.
When popping a scope from the environment stack, we currently do a lot of
nonsense like looking for changed curses variables. We want to centralize
this in env_stack_t so that it can be migrated to the env_dispatch logic.
Move this logic up one level in preparation for doing that.
This new file is supposed to encapsulate all of the logic around
reacting to variable changes, as opposed to the environment core.
This is to help break up the env.cpp monolith.
This switches env_var_t to be an immutable value type, and stores its
contents via a shared_ptr. This eliminates string copying when fetching
env_var_t values.
Mostly related to usage _(L"foo"), keeping in mind the _
macro does a wcstring().c_str() already.
And a smattering of other trivial micro-optimizations certain
to not help tangibly.
Since Unicode 9, the width of some characters changed to 2.
Depending on the system, it might have support for it, or it might
not.
Instead of hardcoding specific glibc etc versions, we check what the
system wcwidth says to "😃", U+1F603 "Grinning Face With Big Eyes".
The intention is to, in most cases, make setting $fish_emoji_width
unnecessary, but since it sets the "guessed_emoji_width", that variable still takes precedence if it is set.
Unfortunately this approach has some caveats:
- It relies on the locale being set to a unicode-supporting one.
(C.UTF-8 is unfortunately not standard, so we can't use it)
- It relies on the terminal's wcwidth having unicode9 support IFF the
system wcwidth does.
This is like #5722, but at runtime.
The additional caveat is that we don't try to achieve a unicode
locale, but since we re-run the heuristic when the locale changes (and
we try to get a unicode locale), we should still often get the correct
value.
Plus if you use a C locale and your terminal still displays emoji,
you've misconfigured your system.
Fixes#5722.
Prior to this fix, an "event" was used as both a predicate on which events
to match, and also as the event itself. Re-express these concepts
distinctly: an event is something that happened, an event_handler is the
predicate and name of the function to execute.
Taking advantage of the maybe_t's, the logic and nesting here
can be a bit less intense.
Small adjustments to debug output, and found a more accurate
version number for Lion Terminal.app.
Longer term we should have a terminal_t class or something
encapsulating all the kinds of terminal detection we have
with methods that return the color support, and also stuff
like whether the terminal has the newline glitch, the
ambiguous width character behavior, etc.
`/tmp` isn't present / writeable on every system. Instead of always
using `/tmp`, try to use standard environment variables and
configuration to find a temporary directory.
Adapted from #3974, with updates based on those comments.
Closes#3845.
