Add cudf::strings::findall_record API

[davidwendt]

Reference #9856 specifically #9856 (comment)

Adds cudf::strings::findall_record which was initially implemented in nvstrings but not ported over since LIST column types did not exist at the time and returning a vector of small columns was very inefficient. This API should also allow using the current python function cudf.str.findall() with the expand=False parameter more effectively. A follow-on PR will address these python changes.

This PR reorganizes the libcudf strings find source files into the cpp/src/strings/search subdirectory as well. Also, findall() has only a regex version so the _re suffix is dropped from the name in the libcudf implementation. The python changes in this PR address only the name change and the addition of the new API in the cython interface.

Depends on #9909 -- shares the cudf::strings::detail::count_matches() utility function.

[codecov]

Codecov Report

Merging #9911 (1f02e97) into branch-22.04 (e24fa8f) will increase coverage by 0.05%.
The diff coverage is n/a.

@@               Coverage Diff                @@
##           branch-22.04    #9911      +/-   ##
================================================
+ Coverage         10.37%   10.43%   +0.05%     
================================================
  Files               119      119              
  Lines             20149    20590     +441     
================================================
+ Hits               2091     2148      +57     
- Misses            18058    18442     +384     

Impacted Files	Coverage Δ
python/cudf/cudf/errors.py	0.00% <0.00%> (ø)
python/cudf/cudf/io/csv.py	0.00% <0.00%> (ø)
python/cudf/cudf/io/hdf.py	0.00% <0.00%> (ø)
python/cudf/cudf/io/orc.py	0.00% <0.00%> (ø)
python/cudf/cudf/__init__.py	0.00% <0.00%> (ø)
python/cudf/cudf/_version.py	0.00% <0.00%> (ø)
python/cudf/cudf/core/abc.py	0.00% <0.00%> (ø)
python/cudf/cudf/api/types.py	0.00% <0.00%> (ø)
python/cudf/cudf/io/dlpack.py	0.00% <0.00%> (ø)
python/cudf/cudf/core/frame.py	0.00% <0.00%> (ø)
... and 60 more

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[robertmaynard]

CMake changes LGTM

[vyasr]

@davidwendt this appears to have fallen through the cracks on my part, apologies. Is this a must for 22.02?

[davidwendt]

... this appears to have fallen through the cracks on my part, apologies. Is this a must for 22.02?

I don't think so. I'll move it.

[vyasr]

I think we need to mark this as breaking since it's changing the name of a public API (findall_re -> findall).
Also, I tried to fix as many copyright years as I could but I probably missed a few (especially those that weren't part of the diff like the copyright line in contains.cpp).

[davidwendt]

@gpucibot merge