Improve performance of cell_length

[darrenburns]

Type of changes

• Bug fix
• New feature
• Documentation / docstrings
• Tests
• Other - performance related change

Checklist

• I've run the latest black with default args on new code.
• I've updated CHANGELOG.md and CONTRIBUTORS.md where appropriate.
• I've added tests for new code.
• I accept that @willmcgugan may be pedantic in the code review.

Description

5-6% performance improvement on python -m rich

Removes the use of the regex for detecting codepoints in ranges we know to be single characters. It was consistently slower regardless of where cache lookups happened.

I've also removed the bounds on key length on the cell_len cache, which resulted in another immediately noticeable improvement.

master:

❯ hyperfine "python -m rich"
Benchmark 1: python -m rich
  Time (mean ± σ):     144.6 ms ±   1.5 ms    [User: 135.5 ms, System: 8.2 ms]
  Range (min … max):   143.5 ms … 150.6 ms    20 runs

this branch:

❯ hyperfine "python -m rich"
Benchmark 1: python -m rich
  Time (mean ± σ):     138.8 ms ±   1.0 ms    [User: 129.6 ms, System: 8.1 ms]
  Range (min … max):   137.3 ms … 142.0 ms    21 runs

Combining this change and the other PR which adjusted regex and caching - cumulative time spend inside cell_len during python -m rich has dropped from 0.02047 to 0.0056. See image below (top is old, bottom is new).

[codecov-commenter]

Codecov Report

Merging #2061 (c4cf06d) into master (91e0146) will increase coverage by 0.02%.
The diff coverage is 91.66%.

@@            Coverage Diff             @@
##           master    #2061      +/-   ##
==========================================
+ Coverage   99.49%   99.52%   +0.02%     
==========================================
  Files          73       72       -1     
  Lines        7361     7331      -30     
==========================================
- Hits         7324     7296      -28     
+ Misses         37       35       -2     

Flag	Coverage Δ
unittests	99.52% <91.66%> (+0.02%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
rich/align.py	100.00% <ø> (ø)
rich/layout.py	100.00% <ø> (ø)
rich/table.py	100.00% <ø> (ø)
rich/console.py	99.50% <80.00%> (-0.13%)	⬇️
rich/_win32_console.py	91.44% <100.00%> (+1.44%)	⬆️
rich/cells.py	100.00% <100.00%> (ø)

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