Move `pathlib.Path.walk()` implementation into `glob._Globber`. The new
`glob._Globber.walk()` classmethod works with strings internally, which is
a little faster than generating `Path` objects and keeping them normalized.
The `pathlib.Path.walk()` method converts the strings back to path objects.

In the private pathlib ABCs, our existing subclass of `_Globber` ensures
that `PathBase` instances are used throughout.

Follow-up to python#117589.

…17726)

Move `pathlib.Path.walk()` implementation into `glob._Globber`. The new
`glob._Globber.walk()` classmethod works with strings internally, which is
a little faster than generating `Path` objects and keeping them normalized.
The `pathlib.Path.walk()` method converts the strings back to path objects.

In the private pathlib ABCs, our existing subclass of `_Globber` ensures
that `PathBase` instances are used throughout.

Follow-up to #117589.

…gs (python#117589)

Move pathlib globbing implementation into a new private class: `glob._Globber`. This class implements fast string-based globbing. It's called by `pathlib.Path.glob()`, which then converts strings back to path objects.

In the private pathlib ABCs, add a `pathlib._abc.Globber` subclass that works with `PathBase` objects rather than strings, and calls user-defined path methods like `PathBase.stat()` rather than `os.stat()`.

This sets the stage for two more improvements:

- pythonGH-115060: Query non-wildcard segments with `lstat()`
- pythonGH-116380: Unify `pathlib` and `glob` implementations of globbing.

No change to the implementations of `glob.glob()` and `glob.iglob()`.

…gs (python#117726)

Move `pathlib.Path.walk()` implementation into `glob._Globber`. The new
`glob._Globber.walk()` classmethod works with strings internally, which is
a little faster than generating `Path` objects and keeping them normalized.
The `pathlib.Path.walk()` method converts the strings back to path objects.

In the private pathlib ABCs, our existing subclass of `_Globber` ensures
that `PathBase` instances are used throughout.

Follow-up to python#117589.

As of python/cpython#117589 (at least),
`Path.glob` returns an `Iterator` rather than `Generator` (which
inherits from `Iterator`).  `convert_file` doesn't need to care about
this distinction; it can reasonably accept both.

This previously caused a test failure along these lines:

  ______________________________________________________ TestPypandoc.test_basic_conversion_from_file_pattern_pathlib_glob _______________________________________________________

  self = <tests.TestPypandoc testMethod=test_basic_conversion_from_file_pattern_pathlib_glob>

      def test_basic_conversion_from_file_pattern_pathlib_glob(self):
          received_from_str_filename_input = pypandoc.convert_file("./*.md", 'html').lower()
  >       received_from_path_filename_input = pypandoc.convert_file(Path(".").glob("*.md"), 'html').lower()

  tests.py:654:
  _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

  source_file = <map object at 0x7f83952c9420>, to = 'html', format = None, extra_args = (), encoding = 'utf-8', outputfile = None, filters = None, verify_format = True
  sandbox = False, cworkdir = '/home/cjwatson/src/python/pypandoc', sort_files = True
  [...]
          if not _identify_path(discovered_source_files):
  >           raise RuntimeError("source_file is not a valid path")
  E           RuntimeError: source_file is not a valid path

  pypandoc/__init__.py:201: RuntimeError

Since python/cpython#117589 (at least),
`Path.glob` and `Path.rglob` return an `Iterator` rather than a
`Generator`.

Since python/cpython#117589 (at least),
`Path.glob` and `Path.rglob` return an `Iterator` rather than a
`Generator`.

As of python/cpython#117589 (at least),
`Path.glob` returns an `Iterator` rather than `Generator` (which
inherits from `Iterator`).  `convert_file` doesn't need to care about
this distinction; it can reasonably accept both.

This previously caused a test failure along these lines:

  ______________________________________________________ TestPypandoc.test_basic_conversion_from_file_pattern_pathlib_glob _______________________________________________________

  self = <tests.TestPypandoc testMethod=test_basic_conversion_from_file_pattern_pathlib_glob>

      def test_basic_conversion_from_file_pattern_pathlib_glob(self):
          received_from_str_filename_input = pypandoc.convert_file("./*.md", 'html').lower()
  >       received_from_path_filename_input = pypandoc.convert_file(Path(".").glob("*.md"), 'html').lower()

  tests.py:654:
  _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

  source_file = <map object at 0x7f83952c9420>, to = 'html', format = None, extra_args = (), encoding = 'utf-8', outputfile = None, filters = None, verify_format = True
  sandbox = False, cworkdir = '/home/cjwatson/src/python/pypandoc', sort_files = True
  [...]
          if not _identify_path(discovered_source_files):
  >           raise RuntimeError("source_file is not a valid path")
  E           RuntimeError: source_file is not a valid path

  pypandoc/__init__.py:201: RuntimeError

Co-authored-by: Jessica Tegner <jessica@jessicategner.com>

Since python/cpython#117589 (at least),
`Path.glob` and `Path.rglob` return an `Iterator` rather than a
`Generator`.

Since python/cpython#117589 (at least),
`Path.glob` and `Path.rglob` return an `Iterator` rather than a
`Generator`.