nushell/crates/nu-protocol/src
Andy Gayton 7b82c6b482
feat: make ctrlc available to plugins (#13181)
# Description

This PR adds a new method to `EngineInterface`: `register_ctrlc_handler`
which takes a closure to run when the plugin's driving engine receives a
ctrlc-signal. It also adds a mirror of the `signals` attribute from the
main shell `EngineState`.

This is an example of how a plugin which makes a long poll http request
can end the request on ctrlc:
https://github.com/cablehead/nu_plugin_http/blob/main/src/commands/request.rs#L68-L77

To facilitate the feature, a new attribute has been added to
`EngineState`: `ctrlc_handlers`. This is a Vec of closures that will be
run when the engine's process receives a ctrlc signal.

When plugins are added to an `engine_state` during a `merge_delta`, the
engine passes the ctrlc_handlers to the plugin's
`.configure_ctrlc_handler` method, which gives the plugin a chance to
register a handler that sends a ctrlc packet through the
`PluginInterface`, if an instance of the plugin is currently running.

On the plugin side: `EngineInterface` also has a ctrlc_handlers Vec of
closures. Plugin calls can use `register_ctrlc_handler` to register a
closure that will be called in the plugin process when the
PluginInput::Ctrlc command is received.

For future reference these are some alternate places that were
investigated for tying the ctrlc trigger to transmitting a Ctrlc packet
through the `PluginInterface`:

- Directly from `src/signals.rs`: the handler there would need a
reference to the Vec<Arc<RegisteredPlugins>>, which would require us to
wrap the plugins in a Mutex, which we don't want to do.

- have `PersistentPlugin.get_plugin` pass down the engine's
CtrlcHandlers to .get and then to .spawn (if the plugin isn't already
running). Once we have CtrlcHandlers in spawn, we can register a handler
to write directly to PluginInterface. We don't want to double down on
passing engine_state to spawn this way though, as it's unpredictable
because it would depend on whether the plugin has already been spawned
or not.

- pass `ctrlc_handlers` to PersistentPlugin::new so it can store it on
itself so it's available to spawn.

- in `PersistentPlugin.spawn`, create a handler that sends to a clone of
the GC event loop's tx. this has the same issues with regards to how to
get CtrlcHandlers to the spawn method, and is more complicated than a
handler that writes directly to PluginInterface

# User-Facing Changes

No breaking changes

---------

Co-authored-by: Ian Manske <ian.manske@pm.me>
2024-07-30 08:29:18 -05:00
..
ast Fix $in in range expressions (#13447) 2024-07-25 18:28:44 +08:00
config Document public types in nu-protocol (#12906) 2024-07-11 13:30:12 +02:00
debugger Overhaul $in expressions (#13357) 2024-07-17 16:02:42 -05:00
engine feat: make ctrlc available to plugins (#13181) 2024-07-30 08:29:18 -05:00
errors Fix bad method links in docstrings (#13471) 2024-07-27 19:39:29 -07:00
ir Make plugins able to find and call other commands (#13407) 2024-07-19 13:54:21 +08:00
pipeline feat: make ctrlc available to plugins (#13181) 2024-07-30 08:29:18 -05:00
plugin feat: make ctrlc available to plugins (#13181) 2024-07-30 08:29:18 -05:00
process Document public types in nu-protocol (#12906) 2024-07-11 13:30:12 +02:00
value Document public types in nu-protocol (#12906) 2024-07-11 13:30:12 +02:00
alias.rs Document public types in nu-protocol (#12906) 2024-07-11 13:30:12 +02:00
did_you_mean.rs Improve case insensitivity consistency (#10884) 2023-11-08 23:58:54 +01:00
eval_base.rs Overhaul $in expressions (#13357) 2024-07-17 16:02:42 -05:00
eval_const.rs Use directories for autoloading (#13382) 2024-07-19 03:47:07 -07:00
example.rs Overhaul the plugin cache file with a new msgpack+brotli format (#12579) 2024-04-21 07:36:26 -05:00
id.rs Internal representation (IR) compiler and evaluator (#13330) 2024-07-10 17:33:59 -07:00
lev_distance.rs Rework for new clippy lints (#12736) 2024-05-02 19:29:03 +02:00
lib.rs Add top-level crate documentation/READMEs (#12907) 2024-07-14 10:10:41 +02:00
module.rs Enable reloading changes to a submodule (#13170) 2024-06-25 18:33:37 -07:00
parser_path.rs Enable reloading changes to a submodule (#13170) 2024-06-25 18:33:37 -07:00
signature.rs Document public types in nu-protocol (#12906) 2024-07-11 13:30:12 +02:00
span.rs Document public types in nu-protocol (#12906) 2024-07-11 13:30:12 +02:00
syntax_shape.rs Make parsing for unknown args in known externals like normal external calls (#13414) 2024-07-21 01:32:36 -07:00
ty.rs Deprecate group in favor of chunks (#13377) 2024-07-16 03:49:00 +00:00