mirror of https://github.com/python/cpython
GH-126363: Speed up pattern parsing in `pathlib.Path.glob()` (#126364)
The implementation of `Path.glob()` does rather a hacky thing: it calls `self.with_segments()` to convert the given pattern to a `Path` object, and then peeks at the private `_raw_path` attribute to see if pathlib removed a trailing slash from the pattern. In this patch, we make `glob()` use a new `_parse_pattern()` classmethod that splits the pattern into parts while preserving information about any trailing slash. This skips the cost of creating a `Path` object, and avoids some path anchor normalization, which makes `Path.glob()` slightly faster. But mostly it's about making the code less naughty. Co-authored-by: Tomas R. <tomas.roun8@gmail.com>
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@ -274,6 +274,31 @@ class PurePath(PurePathBase):
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root = sep
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return drv, root, [x for x in rel.split(sep) if x and x != '.']
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@classmethod
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def _parse_pattern(cls, pattern):
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"""Parse a glob pattern to a list of parts. This is much like
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_parse_path, except:
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- Rather than normalizing and returning the drive and root, we raise
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NotImplementedError if either are present.
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- If the path has no real parts, we raise ValueError.
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- If the path ends in a slash, then a final empty part is added.
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"""
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drv, root, rel = cls.parser.splitroot(pattern)
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if root or drv:
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raise NotImplementedError("Non-relative patterns are unsupported")
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sep = cls.parser.sep
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altsep = cls.parser.altsep
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if altsep:
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rel = rel.replace(altsep, sep)
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parts = [x for x in rel.split(sep) if x and x != '.']
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if not parts:
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raise ValueError(f"Unacceptable pattern: {str(pattern)!r}")
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elif rel.endswith(sep):
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# GH-65238: preserve trailing slash in glob patterns.
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parts.append('')
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return parts
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@property
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def _raw_path(self):
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"""The joined but unnormalized path."""
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@ -641,17 +666,7 @@ class Path(PathBase, PurePath):
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kind, including directories) matching the given relative pattern.
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"""
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sys.audit("pathlib.Path.glob", self, pattern)
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if not isinstance(pattern, PurePath):
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pattern = self.with_segments(pattern)
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if pattern.anchor:
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raise NotImplementedError("Non-relative patterns are unsupported")
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parts = pattern._tail.copy()
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if not parts:
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raise ValueError("Unacceptable pattern: {!r}".format(pattern))
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raw = pattern._raw_path
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if raw[-1] in (self.parser.sep, self.parser.altsep):
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# GH-65238: pathlib doesn't preserve trailing slash. Add it back.
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parts.append('')
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parts = self._parse_pattern(pattern)
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select = self._glob_selector(parts[::-1], case_sensitive, recurse_symlinks)
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root = str(self)
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paths = select(root)
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@ -672,9 +687,7 @@ class Path(PathBase, PurePath):
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this subtree.
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"""
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sys.audit("pathlib.Path.rglob", self, pattern)
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if not isinstance(pattern, PurePath):
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pattern = self.with_segments(pattern)
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pattern = '**' / pattern
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pattern = self.parser.join('**', pattern)
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return self.glob(pattern, case_sensitive=case_sensitive, recurse_symlinks=recurse_symlinks)
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def walk(self, top_down=True, on_error=None, follow_symlinks=False):
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@ -0,0 +1,2 @@
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Speed up pattern parsing in :meth:`pathlib.Path.glob` by skipping creation
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of a :class:`pathlib.Path` object for the pattern.
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