nushell/crates/nu-command/src
Devyn Cairns 2ae9ad8676
Copy-on-write for record values (#12305)
# Description
This adds a `SharedCow` type as a transparent copy-on-write pointer that
clones to unique on mutate.

As an initial test, the `Record` within `Value::Record` is shared.

There are some pretty big wins for performance. I'll post benchmark
results in a comment. The biggest winner is nested access, as that would
have cloned the records for each cell path follow before and it doesn't
have to anymore.

The reusability of the `SharedCow` type is nice and I think it could be
used to clean up the previous work I did with `Arc` in `EngineState`.
It's meant to be a mostly transparent clone-on-write that just clones on
`.to_mut()` or `.into_owned()` if there are actually multiple
references, but avoids cloning if the reference is unique.

# User-Facing Changes
- `Value::Record` field is a different type (plugin authors)

# Tests + Formatting
- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`

# After Submitting
- [ ] use for `EngineState`
- [ ] use for `Value::List`
2024-04-14 01:42:03 +00:00
..
bytes Add command_prelude module (#12291) 2024-03-26 21:17:30 +00:00
charting Copy-on-write for record values (#12305) 2024-04-14 01:42:03 +00:00
conversions Copy-on-write for record values (#12305) 2024-04-14 01:42:03 +00:00
database Copy-on-write for record values (#12305) 2024-04-14 01:42:03 +00:00
date Add command_prelude module (#12291) 2024-03-26 21:17:30 +00:00
debug Copy-on-write for record values (#12305) 2024-04-14 01:42:03 +00:00
env Copy-on-write for record values (#12305) 2024-04-14 01:42:03 +00:00
experimental Add command_prelude module (#12291) 2024-03-26 21:17:30 +00:00
filesystem making ls and du supports rest parameters. (#12327) 2024-04-13 15:03:17 +00:00
filters Copy-on-write for record values (#12305) 2024-04-14 01:42:03 +00:00
formats Copy-on-write for record values (#12305) 2024-04-14 01:42:03 +00:00
generators Copy-on-write for record values (#12305) 2024-04-14 01:42:03 +00:00
hash Add command_prelude module (#12291) 2024-03-26 21:17:30 +00:00
help Copy-on-write for record values (#12305) 2024-04-14 01:42:03 +00:00
math Copy-on-write for record values (#12305) 2024-04-14 01:42:03 +00:00
misc Add command_prelude module (#12291) 2024-03-26 21:17:30 +00:00
network Copy-on-write for record values (#12305) 2024-04-14 01:42:03 +00:00
path Add command_prelude module (#12291) 2024-03-26 21:17:30 +00:00
platform Return value instead of stream from kill (#12480) 2024-04-12 10:44:27 -05:00
random Range refactor (#12405) 2024-04-06 09:04:56 -05:00
removed Add command_prelude module (#12291) 2024-03-26 21:17:30 +00:00
shells Add command_prelude module (#12291) 2024-03-26 21:17:30 +00:00
stor Fix typo in help stor import (#12442) 2024-04-07 08:09:24 -05:00
strings Fix nushell#10591: encode returns error with utf-16le and utf-16be encodings (nushell#10591) (#12411) 2024-04-06 09:07:55 -05:00
system Rename IoStream to OutDest (#12433) 2024-04-09 16:48:32 +00:00
viewers Copy-on-write for record values (#12305) 2024-04-14 01:42:03 +00:00
default_context.rs Use nightly clippy to kill dead code/fix style (#12334) 2024-03-30 09:17:28 +08:00
example_test.rs Initial --params implementation (#12249) 2024-03-24 15:40:21 -05:00
lib.rs Initial --params implementation (#12249) 2024-03-24 15:40:21 -05:00
progress_bar.rs remove cp-old (#11622) 2024-01-24 07:38:15 +08:00
sort_utils.rs Rename Value::CustomValue to Value::Custom (#12309) 2024-03-27 22:10:56 +01:00