Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

13 files changed, 2415 insertions, 0 deletions

diff --git a/third_party/python/pathspec/pathspec-0.9.0.dist-info/LICENSE b/third_party/python/pathspec/pathspec-0.9.0.dist-info/LICENSE
new file mode 100644
index 0000000000..14e2f777f6
--- /dev/null
+++ b/third_party/python/pathspec/pathspec-0.9.0.dist-info/LICENSE
@@ -0,0 +1,373 @@
+Mozilla Public License Version 2.0
+==================================
+
+1. Definitions
+--------------
+
+1.1. "Contributor"
+    means each individual or legal entity that creates, contributes to
+    the creation of, or owns Covered Software.
+
+1.2. "Contributor Version"
+    means the combination of the Contributions of others (if any) used
+    by a Contributor and that particular Contributor's Contribution.
+
+1.3. "Contribution"
+    means Covered Software of a particular Contributor.
+
+1.4. "Covered Software"
+    means Source Code Form to which the initial Contributor has attached
+    the notice in Exhibit A, the Executable Form of such Source Code
+    Form, and Modifications of such Source Code Form, in each case
+    including portions thereof.
+
+1.5. "Incompatible With Secondary Licenses"
+    means
+
+    (a) that the initial Contributor has attached the notice described
+        in Exhibit B to the Covered Software; or
+
+    (b) that the Covered Software was made available under the terms of
+        version 1.1 or earlier of the License, but not also under the
+        terms of a Secondary License.
+
+1.6. "Executable Form"
+    means any form of the work other than Source Code Form.
+
+1.7. "Larger Work"
+    means a work that combines Covered Software with other material, in 
+    a separate file or files, that is not Covered Software.
+
+1.8. "License"
+    means this document.
+
+1.9. "Licensable"
+    means having the right to grant, to the maximum extent possible,
+    whether at the time of the initial grant or subsequently, any and
+    all of the rights conveyed by this License.
+
+1.10. "Modifications"
+    means any of the following:
+
+    (a) any file in Source Code Form that results from an addition to,
+        deletion from, or modification of the contents of Covered
+        Software; or
+
+    (b) any new file in Source Code Form that contains any Covered
+        Software.
+
+1.11. "Patent Claims" of a Contributor
+    means any patent claim(s), including without limitation, method,
+    process, and apparatus claims, in any patent Licensable by such
+    Contributor that would be infringed, but for the grant of the
+    License, by the making, using, selling, offering for sale, having
+    made, import, or transfer of either its Contributions or its
+    Contributor Version.
+
+1.12. "Secondary License"
+    means either the GNU General Public License, Version 2.0, the GNU
+    Lesser General Public License, Version 2.1, the GNU Affero General
+    Public License, Version 3.0, or any later versions of those
+    licenses.
+
+1.13. "Source Code Form"
+    means the form of the work preferred for making modifications.
+
+1.14. "You" (or "Your")
+    means an individual or a legal entity exercising rights under this
+    License. For legal entities, "You" includes any entity that
+    controls, is controlled by, or is under common control with You. For
+    purposes of this definition, "control" means (a) the power, direct
+    or indirect, to cause the direction or management of such entity,
+    whether by contract or otherwise, or (b) ownership of more than
+    fifty percent (50%) of the outstanding shares or beneficial
+    ownership of such entity.
+
+2. License Grants and Conditions
+--------------------------------
+
+2.1. Grants
+
+Each Contributor hereby grants You a world-wide, royalty-free,
+non-exclusive license:
+
+(a) under intellectual property rights (other than patent or trademark)
+    Licensable by such Contributor to use, reproduce, make available,
+    modify, display, perform, distribute, and otherwise exploit its
+    Contributions, either on an unmodified basis, with Modifications, or
+    as part of a Larger Work; and
+
+(b) under Patent Claims of such Contributor to make, use, sell, offer
+    for sale, have made, import, and otherwise transfer either its
+    Contributions or its Contributor Version.
+
+2.2. Effective Date
+
+The licenses granted in Section 2.1 with respect to any Contribution
+become effective for each Contribution on the date the Contributor first
+distributes such Contribution.
+
+2.3. Limitations on Grant Scope
+
+The licenses granted in this Section 2 are the only rights granted under
+this License. No additional rights or licenses will be implied from the
+distribution or licensing of Covered Software under this License.
+Notwithstanding Section 2.1(b) above, no patent license is granted by a
+Contributor:
+
+(a) for any code that a Contributor has removed from Covered Software;
+    or
+
+(b) for infringements caused by: (i) Your and any other third party's
+    modifications of Covered Software, or (ii) the combination of its
+    Contributions with other software (except as part of its Contributor
+    Version); or
+
+(c) under Patent Claims infringed by Covered Software in the absence of
+    its Contributions.
+
+This License does not grant any rights in the trademarks, service marks,
+or logos of any Contributor (except as may be necessary to comply with
+the notice requirements in Section 3.4).
+
+2.4. Subsequent Licenses
+
+No Contributor makes additional grants as a result of Your choice to
+distribute the Covered Software under a subsequent version of this
+License (see Section 10.2) or under the terms of a Secondary License (if
+permitted under the terms of Section 3.3).
+
+2.5. Representation
+
+Each Contributor represents that the Contributor believes its
+Contributions are its original creation(s) or it has sufficient rights
+to grant the rights to its Contributions conveyed by this License.
+
+2.6. Fair Use
+
+This License is not intended to limit any rights You have under
+applicable copyright doctrines of fair use, fair dealing, or other
+equivalents.
+
+2.7. Conditions
+
+Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted
+in Section 2.1.
+
+3. Responsibilities
+-------------------
+
+3.1. Distribution of Source Form
+
+All distribution of Covered Software in Source Code Form, including any
+Modifications that You create or to which You contribute, must be under
+the terms of this License. You must inform recipients that the Source
+Code Form of the Covered Software is governed by the terms of this
+License, and how they can obtain a copy of this License. You may not
+attempt to alter or restrict the recipients' rights in the Source Code
+Form.
+
+3.2. Distribution of Executable Form
+
+If You distribute Covered Software in Executable Form then:
+
+(a) such Covered Software must also be made available in Source Code
+    Form, as described in Section 3.1, and You must inform recipients of
+    the Executable Form how they can obtain a copy of such Source Code
+    Form by reasonable means in a timely manner, at a charge no more
+    than the cost of distribution to the recipient; and
+
+(b) You may distribute such Executable Form under the terms of this
+    License, or sublicense it under different terms, provided that the
+    license for the Executable Form does not attempt to limit or alter
+    the recipients' rights in the Source Code Form under this License.
+
+3.3. Distribution of a Larger Work
+
+You may create and distribute a Larger Work under terms of Your choice,
+provided that You also comply with the requirements of this License for
+the Covered Software. If the Larger Work is a combination of Covered
+Software with a work governed by one or more Secondary Licenses, and the
+Covered Software is not Incompatible With Secondary Licenses, this
+License permits You to additionally distribute such Covered Software
+under the terms of such Secondary License(s), so that the recipient of
+the Larger Work may, at their option, further distribute the Covered
+Software under the terms of either this License or such Secondary
+License(s).
+
+3.4. Notices
+
+You may not remove or alter the substance of any license notices
+(including copyright notices, patent notices, disclaimers of warranty,
+or limitations of liability) contained within the Source Code Form of
+the Covered Software, except that You may alter any license notices to
+the extent required to remedy known factual inaccuracies.
+
+3.5. Application of Additional Terms
+
+You may choose to offer, and to charge a fee for, warranty, support,
+indemnity or liability obligations to one or more recipients of Covered
+Software. However, You may do so only on Your own behalf, and not on
+behalf of any Contributor. You must make it absolutely clear that any
+such warranty, support, indemnity, or liability obligation is offered by
+You alone, and You hereby agree to indemnify every Contributor for any
+liability incurred by such Contributor as a result of warranty, support,
+indemnity or liability terms You offer. You may include additional
+disclaimers of warranty and limitations of liability specific to any
+jurisdiction.
+
+4. Inability to Comply Due to Statute or Regulation
+---------------------------------------------------
+
+If it is impossible for You to comply with any of the terms of this
+License with respect to some or all of the Covered Software due to
+statute, judicial order, or regulation then You must: (a) comply with
+the terms of this License to the maximum extent possible; and (b)
+describe the limitations and the code they affect. Such description must
+be placed in a text file included with all distributions of the Covered
+Software under this License. Except to the extent prohibited by statute
+or regulation, such description must be sufficiently detailed for a
+recipient of ordinary skill to be able to understand it.
+
+5. Termination
+--------------
+
+5.1. The rights granted under this License will terminate automatically
+if You fail to comply with any of its terms. However, if You become
+compliant, then the rights granted under this License from a particular
+Contributor are reinstated (a) provisionally, unless and until such
+Contributor explicitly and finally terminates Your grants, and (b) on an
+ongoing basis, if such Contributor fails to notify You of the
+non-compliance by some reasonable means prior to 60 days after You have
+come back into compliance. Moreover, Your grants from a particular
+Contributor are reinstated on an ongoing basis if such Contributor
+notifies You of the non-compliance by some reasonable means, this is the
+first time You have received notice of non-compliance with this License
+from such Contributor, and You become compliant prior to 30 days after
+Your receipt of the notice.
+
+5.2. If You initiate litigation against any entity by asserting a patent
+infringement claim (excluding declaratory judgment actions,
+counter-claims, and cross-claims) alleging that a Contributor Version
+directly or indirectly infringes any patent, then the rights granted to
+You by any and all Contributors for the Covered Software under Section
+2.1 of this License shall terminate.
+
+5.3. In the event of termination under Sections 5.1 or 5.2 above, all
+end user license agreements (excluding distributors and resellers) which
+have been validly granted by You or Your distributors under this License
+prior to termination shall survive termination.
+
+************************************************************************
+*                                                                      *
+*  6. Disclaimer of Warranty                                           *
+*  -------------------------                                           *
+*                                                                      *
+*  Covered Software is provided under this License on an "as is"       *
+*  basis, without warranty of any kind, either expressed, implied, or  *
+*  statutory, including, without limitation, warranties that the       *
+*  Covered Software is free of defects, merchantable, fit for a        *
+*  particular purpose or non-infringing. The entire risk as to the     *
+*  quality and performance of the Covered Software is with You.        *
+*  Should any Covered Software prove defective in any respect, You     *
+*  (not any Contributor) assume the cost of any necessary servicing,   *
+*  repair, or correction. This disclaimer of warranty constitutes an   *
+*  essential part of this License. No use of any Covered Software is   *
+*  authorized under this License except under this disclaimer.         *
+*                                                                      *
+************************************************************************
+
+************************************************************************
+*                                                                      *
+*  7. Limitation of Liability                                          *
+*  --------------------------                                          *
+*                                                                      *
+*  Under no circumstances and under no legal theory, whether tort      *
+*  (including negligence), contract, or otherwise, shall any           *
+*  Contributor, or anyone who distributes Covered Software as          *
+*  permitted above, be liable to You for any direct, indirect,         *
+*  special, incidental, or consequential damages of any character      *
+*  including, without limitation, damages for lost profits, loss of    *
+*  goodwill, work stoppage, computer failure or malfunction, or any    *
+*  and all other commercial damages or losses, even if such party      *
+*  shall have been informed of the possibility of such damages. This   *
+*  limitation of liability shall not apply to liability for death or   *
+*  personal injury resulting from such party's negligence to the       *
+*  extent applicable law prohibits such limitation. Some               *
+*  jurisdictions do not allow the exclusion or limitation of           *
+*  incidental or consequential damages, so this exclusion and          *
+*  limitation may not apply to You.                                    *
+*                                                                      *
+************************************************************************
+
+8. Litigation
+-------------
+
+Any litigation relating to this License may be brought only in the
+courts of a jurisdiction where the defendant maintains its principal
+place of business and such litigation shall be governed by laws of that
+jurisdiction, without reference to its conflict-of-law provisions.
+Nothing in this Section shall prevent a party's ability to bring
+cross-claims or counter-claims.
+
+9. Miscellaneous
+----------------
+
+This License represents the complete agreement concerning the subject
+matter hereof. If any provision of this License is held to be
+unenforceable, such provision shall be reformed only to the extent
+necessary to make it enforceable. Any law or regulation which provides
+that the language of a contract shall be construed against the drafter
+shall not be used to construe this License against a Contributor.
+
+10. Versions of the License
+---------------------------
+
+10.1. New Versions
+
+Mozilla Foundation is the license steward. Except as provided in Section
+10.3, no one other than the license steward has the right to modify or
+publish new versions of this License. Each version will be given a
+distinguishing version number.
+
+10.2. Effect of New Versions
+
+You may distribute the Covered Software under the terms of the version
+of the License under which You originally received the Covered Software,
+or under the terms of any subsequent version published by the license
+steward.
+
+10.3. Modified Versions
+
+If you create software not governed by this License, and you want to
+create a new license for such software, you may create and use a
+modified version of this License if you rename the license and remove
+any references to the name of the license steward (except to note that
+such modified license differs from this License).
+
+10.4. Distributing Source Code Form that is Incompatible With Secondary
+Licenses
+
+If You choose to distribute Source Code Form that is Incompatible With
+Secondary Licenses under the terms of this version of the License, the
+notice described in Exhibit B of this License must be attached.
+
+Exhibit A - Source Code Form License Notice
+-------------------------------------------
+
+  This Source Code Form is subject to the terms of the Mozilla Public
+  License, v. 2.0. If a copy of the MPL was not distributed with this
+  file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+If it is not possible or desirable to put the notice in a particular
+file, then You may include the notice in a location (such as a LICENSE
+file in a relevant directory) where a recipient would be likely to look
+for such a notice.
+
+You may add additional accurate notices of copyright ownership.
+
+Exhibit B - "Incompatible With Secondary Licenses" Notice
+---------------------------------------------------------
+
+  This Source Code Form is "Incompatible With Secondary Licenses", as
+  defined by the Mozilla Public License, v. 2.0.
diff --git a/third_party/python/pathspec/pathspec-0.9.0.dist-info/METADATA b/third_party/python/pathspec/pathspec-0.9.0.dist-info/METADATA
new file mode 100644
index 0000000000..2d38736204
--- /dev/null
+++ b/third_party/python/pathspec/pathspec-0.9.0.dist-info/METADATA
@@ -0,0 +1,411 @@
+Metadata-Version: 2.1
+Name: pathspec
+Version: 0.9.0
+Summary: Utility library for gitignore style pattern matching of file paths.
+Home-page: https://github.com/cpburnz/python-path-specification
+Author: Caleb P. Burns
+Author-email: cpburnz@gmail.com
+License: MPL 2.0
+Platform: UNKNOWN
+Classifier: Development Status :: 4 - Beta
+Classifier: Intended Audience :: Developers
+Classifier: License :: OSI Approved :: Mozilla Public License 2.0 (MPL 2.0)
+Classifier: Operating System :: OS Independent
+Classifier: Programming Language :: Python
+Classifier: Programming Language :: Python :: 2
+Classifier: Programming Language :: Python :: 2.7
+Classifier: Programming Language :: Python :: 3
+Classifier: Programming Language :: Python :: 3.5
+Classifier: Programming Language :: Python :: 3.6
+Classifier: Programming Language :: Python :: 3.7
+Classifier: Programming Language :: Python :: 3.8
+Classifier: Programming Language :: Python :: 3.9
+Classifier: Programming Language :: Python :: Implementation :: CPython
+Classifier: Programming Language :: Python :: Implementation :: PyPy
+Classifier: Topic :: Software Development :: Libraries :: Python Modules
+Classifier: Topic :: Utilities
+Requires-Python: !=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,>=2.7
+Description-Content-Type: text/x-rst
+
+
+*pathspec*: Path Specification
+==============================
+
+*pathspec* is a utility library for pattern matching of file paths. So
+far this only includes Git's wildmatch pattern matching which itself is
+derived from Rsync's wildmatch. Git uses wildmatch for its `gitignore`_
+files.
+
+.. _`gitignore`: http://git-scm.com/docs/gitignore
+
+
+Tutorial
+--------
+
+Say you have a "Projects" directory and you want to back it up, but only
+certain files, and ignore others depending on certain conditions::
+
+	>>> import pathspec
+	>>> # The gitignore-style patterns for files to select, but we're including
+	>>> # instead of ignoring.
+	>>> spec = """
+	...
+	... # This is a comment because the line begins with a hash: "#"
+	...
+	... # Include several project directories (and all descendants) relative to
+	... # the current directory. To reference a directory you must end with a
+	... # slash: "/"
+	... /project-a/
+	... /project-b/
+	... /project-c/
+	...
+	... # Patterns can be negated by prefixing with exclamation mark: "!"
+	...
+	... # Ignore temporary files beginning or ending with "~" and ending with
+	... # ".swp".
+	... !~*
+	... !*~
+	... !*.swp
+	...
+	... # These are python projects so ignore compiled python files from
+	... # testing.
+	... !*.pyc
+	...
+	... # Ignore the build directories but only directly under the project
+	... # directories.
+	... !/*/build/
+	...
+	... """
+
+We want to use the ``GitWildMatchPattern`` class to compile our patterns. The
+``PathSpec`` class provides an interface around pattern implementations::
+
+	>>> spec = pathspec.PathSpec.from_lines(pathspec.patterns.GitWildMatchPattern, spec.splitlines())
+
+That may be a mouthful but it allows for additional patterns to be implemented
+in the future without them having to deal with anything but matching the paths
+sent to them. ``GitWildMatchPattern`` is the implementation of the actual
+pattern which internally gets converted into a regular expression.
+``PathSpec`` is a simple wrapper around a list of compiled patterns.
+
+To make things simpler, we can use the registered name for a pattern class
+instead of always having to provide a reference to the class itself. The
+``GitWildMatchPattern`` class is registered as **gitwildmatch**::
+
+	>>> spec = pathspec.PathSpec.from_lines('gitwildmatch', spec.splitlines())
+
+If we wanted to manually compile the patterns we can just do the following::
+
+	>>> patterns = map(pathspec.patterns.GitWildMatchPattern, spec.splitlines())
+	>>> spec = PathSpec(patterns)
+
+``PathSpec.from_lines()`` is simply a class method which does just that.
+
+If you want to load the patterns from file, you can pass the file instance
+directly as well::
+
+	>>> with open('patterns.list', 'r') as fh:
+	>>>     spec = pathspec.PathSpec.from_lines('gitwildmatch', fh)
+
+You can perform matching on a whole directory tree with::
+
+	>>> matches = spec.match_tree('path/to/directory')
+
+Or you can perform matching on a specific set of file paths with::
+
+	>>> matches = spec.match_files(file_paths)
+
+Or check to see if an individual file matches::
+
+	>>> is_matched = spec.match_file(file_path)
+
+
+License
+-------
+
+*pathspec* is licensed under the `Mozilla Public License Version 2.0`_. See
+`LICENSE`_ or the `FAQ`_ for more information.
+
+In summary, you may use *pathspec* with any closed or open source project
+without affecting the license of the larger work so long as you:
+
+- give credit where credit is due,
+
+- and release any custom changes made to *pathspec*.
+
+.. _`Mozilla Public License Version 2.0`: http://www.mozilla.org/MPL/2.0
+.. _`LICENSE`: LICENSE
+.. _`FAQ`: http://www.mozilla.org/MPL/2.0/FAQ.html
+
+
+Source
+------
+
+The source code for *pathspec* is available from the GitHub repo
+`cpburnz/python-path-specification`_.
+
+.. _`cpburnz/python-path-specification`: https://github.com/cpburnz/python-path-specification
+
+
+Installation
+------------
+
+*pathspec* requires the following packages:
+
+- `setuptools`_
+
+*pathspec* can be installed from source with::
+
+	python setup.py install
+
+*pathspec* is also available for install through `PyPI`_::
+
+	pip install pathspec
+
+.. _`setuptools`: https://pypi.python.org/pypi/setuptools
+.. _`PyPI`: http://pypi.python.org/pypi/pathspec
+
+
+Documentation
+-------------
+
+Documentation for *pathspec* is available on `Read the Docs`_.
+
+.. _`Read the Docs`: http://python-path-specification.readthedocs.io
+
+
+Other Languages
+---------------
+
+*pathspec* is also available as a `Ruby gem`_.
+
+.. _`Ruby gem`: https://github.com/highb/pathspec-ruby
+
+
+Change History
+==============
+
+0.9.0 (2021-07-17)
+------------------
+
+- `Issue #44`_/`Issue #50`_: Raise `GitWildMatchPatternError` for invalid git patterns.
+- `Issue #45`_: Fix for duplicate leading double-asterisk, and edge cases.
+- `Issue #46`_: Fix matching absolute paths.
+- API change: `util.normalize_files()` now returns a `Dict[str, List[pathlike]]` instead of a `Dict[str, pathlike]`.
+- Added type hinting.
+
+.. _`Issue #44`: https://github.com/cpburnz/python-path-specification/issues/44
+.. _`Issue #45`: https://github.com/cpburnz/python-path-specification/pull/45
+.. _`Issue #46`: https://github.com/cpburnz/python-path-specification/issues/46
+.. _`Issue #50`: https://github.com/cpburnz/python-path-specification/pull/50
+
+
+0.8.1 (2020-11-07)
+------------------
+
+- `Issue #43`_: Add support for addition operator.
+
+.. _`Issue #43`: https://github.com/cpburnz/python-path-specification/pull/43
+
+
+0.8.0 (2020-04-09)
+------------------
+
+- `Issue #30`_: Expose what patterns matched paths. Added `util.detailed_match_files()`.
+- `Issue #31`_: `match_tree()` doesn't return symlinks.
+- `Issue #34`_: Support `pathlib.Path`\ s.
+- Add `PathSpec.match_tree_entries` and `util.iter_tree_entries()` to support directories and symlinks.
+- API change: `match_tree()` has been renamed to `match_tree_files()`. The old name `match_tree()` is still available as an alias.
+- API change: `match_tree_files()` now returns symlinks. This is a bug fix but it will change the returned results.
+
+.. _`Issue #30`: https://github.com/cpburnz/python-path-specification/issues/30
+.. _`Issue #31`: https://github.com/cpburnz/python-path-specification/issues/31
+.. _`Issue #34`: https://github.com/cpburnz/python-path-specification/issues/34
+
+
+0.7.0 (2019-12-27)
+------------------
+
+- `Issue #28`_: Add support for Python 3.8, and drop Python 3.4.
+- `Issue #29`_: Publish bdist wheel.
+
+.. _`Issue #28`: https://github.com/cpburnz/python-path-specification/pull/28
+.. _`Issue #29`: https://github.com/cpburnz/python-path-specification/pull/29
+
+
+0.6.0 (2019-10-03)
+------------------
+
+- `Issue #24`_: Drop support for Python 2.6, 3.2, and 3.3.
+- `Issue #25`_: Update README.rst.
+- `Issue #26`_: Method to escape gitwildmatch.
+
+.. _`Issue #24`: https://github.com/cpburnz/python-path-specification/pull/24
+.. _`Issue #25`: https://github.com/cpburnz/python-path-specification/pull/25
+.. _`Issue #26`: https://github.com/cpburnz/python-path-specification/pull/26
+
+
+0.5.9 (2018-09-15)
+------------------
+
+- Fixed file system error handling.
+
+
+0.5.8 (2018-09-15)
+------------------
+
+- Improved type checking.
+- Created scripts to test Python 2.6 because Tox removed support for it.
+- Improved byte string handling in Python 3.
+- `Issue #22`_: Handle dangling symlinks.
+
+.. _`Issue #22`: https://github.com/cpburnz/python-path-specification/issues/22
+
+
+0.5.7 (2018-08-14)
+------------------
+
+- `Issue #21`_: Fix collections deprecation warning.
+
+.. _`Issue #21`: https://github.com/cpburnz/python-path-specification/issues/21
+
+
+0.5.6 (2018-04-06)
+------------------
+
+- Improved unit tests.
+- Improved type checking.
+- `Issue #20`_: Support current directory prefix.
+
+.. _`Issue #20`: https://github.com/cpburnz/python-path-specification/issues/20
+
+
+0.5.5 (2017-09-09)
+------------------
+
+- Add documentation link to README.
+
+
+0.5.4 (2017-09-09)
+------------------
+
+- `Issue #17`_: Add link to Ruby implementation of *pathspec*.
+- Add sphinx documentation.
+
+.. _`Issue #17`: https://github.com/cpburnz/python-path-specification/pull/17
+
+
+0.5.3 (2017-07-01)
+------------------
+
+- `Issue #14`_: Fix byte strings for Python 3.
+- `Issue #15`_: Include "LICENSE" in source package.
+- `Issue #16`_: Support Python 2.6.
+
+.. _`Issue #14`: https://github.com/cpburnz/python-path-specification/issues/14
+.. _`Issue #15`: https://github.com/cpburnz/python-path-specification/pull/15
+.. _`Issue #16`: https://github.com/cpburnz/python-path-specification/issues/16
+
+
+0.5.2 (2017-04-04)
+------------------
+
+- Fixed change log.
+
+
+0.5.1 (2017-04-04)
+------------------
+
+- `Issue #13`_: Add equality methods to `PathSpec` and `RegexPattern`.
+
+.. _`Issue #13`: https://github.com/cpburnz/python-path-specification/pull/13
+
+
+0.5.0 (2016-08-22)
+------------------
+
+- `Issue #12`_: Add `PathSpec.match_file()`.
+- Renamed `gitignore.GitIgnorePattern` to `patterns.gitwildmatch.GitWildMatchPattern`.
+- Deprecated `gitignore.GitIgnorePattern`.
+
+.. _`Issue #12`: https://github.com/cpburnz/python-path-specification/issues/12
+
+
+0.4.0 (2016-07-15)
+------------------
+
+- `Issue #11`_: Support converting patterns into regular expressions without compiling them.
+- API change: Subclasses of `RegexPattern` should implement `pattern_to_regex()`.
+
+.. _`Issue #11`: https://github.com/cpburnz/python-path-specification/issues/11
+
+
+0.3.4 (2015-08-24)
+------------------
+
+- `Issue #7`_: Fixed non-recursive links.
+- `Issue #8`_: Fixed edge cases in gitignore patterns.
+- `Issue #9`_: Fixed minor usage documentation.
+- Fixed recursion detection.
+- Fixed trivial incompatibility with Python 3.2.
+
+.. _`Issue #7`: https://github.com/cpburnz/python-path-specification/pull/7
+.. _`Issue #8`: https://github.com/cpburnz/python-path-specification/pull/8
+.. _`Issue #9`: https://github.com/cpburnz/python-path-specification/pull/9
+
+
+0.3.3 (2014-11-21)
+------------------
+
+- Improved documentation.
+
+
+0.3.2 (2014-11-08)
+------------------
+
+- `Issue #5`_: Use tox for testing.
+- `Issue #6`_: Fixed matching Windows paths.
+- Improved documentation.
+- API change: `spec.match_tree()` and `spec.match_files()` now return iterators instead of sets.
+
+.. _`Issue #5`: https://github.com/cpburnz/python-path-specification/pull/5
+.. _`Issue #6`: https://github.com/cpburnz/python-path-specification/issues/6
+
+
+0.3.1 (2014-09-17)
+------------------
+
+- Updated README.
+
+
+0.3.0 (2014-09-17)
+------------------
+
+- `Issue #3`_: Fixed trailing slash in gitignore patterns.
+- `Issue #4`_: Fixed test for trailing slash in gitignore patterns.
+- Added registered patterns.
+
+.. _`Issue #3`: https://github.com/cpburnz/python-path-specification/pull/3
+.. _`Issue #4`: https://github.com/cpburnz/python-path-specification/pull/4
+
+
+0.2.2 (2013-12-17)
+------------------
+
+- Fixed setup.py.
+
+
+0.2.1 (2013-12-17)
+------------------
+
+- Added tests.
+- Fixed comment gitignore patterns.
+- Fixed relative path gitignore patterns.
+
+
+0.2.0 (2013-12-07)
+------------------
+
+- Initial release.
+
+
diff --git a/third_party/python/pathspec/pathspec-0.9.0.dist-info/RECORD b/third_party/python/pathspec/pathspec-0.9.0.dist-info/RECORD
new file mode 100644
index 0000000000..328aa58483
--- /dev/null
+++ b/third_party/python/pathspec/pathspec-0.9.0.dist-info/RECORD
@@ -0,0 +1,17 @@
+pathspec/__init__.py,sha256=72Wc9H_-xRaisgbnz3pNf8bJJlFu6ZP3MMEYVvlIowk,1085
+pathspec/_meta.py,sha256=MyOTCY28N1FOIxhPQBNxXei9oiQEvzVISrwnyCIAb-0,1617
+pathspec/compat.py,sha256=G0_QT3NRlFTcrV1bhx9G1qIvBdmnaWh-f4VrcpXzfhc,830
+pathspec/pathspec.py,sha256=J2lrhvT1iqkZ5rSrTvMEOjuLBkdzl2QVZkJYWIoMVmw,8048
+pathspec/pattern.py,sha256=sWBuHJNnDKa6tqpKU50ZeCUYXSkKz2dWPLtSHpIyP5U,4811
+pathspec/util.py,sha256=XayuxOvE0LaTZDyffhpel-1ew1_MP_FTCeqXj0M3C8I,19889
+pathspec/patterns/__init__.py,sha256=Falv9rzI0S-Sjc-t-vCS9nUPcKwBptmdNderY9Kok50,184
+pathspec/patterns/gitwildmatch.py,sha256=NzrN7IqFvJJT3x7jcXIMZBmeWF6n0nDjUMoPWpGmvZs,11899
+pathspec/tests/__init__.py,sha256=47DEQpj8HBSa-_TImW-5JCeuQeRkm5NMpJWZG3hSuFU,0
+pathspec/tests/test_gitwildmatch.py,sha256=m9a5-dJ1-MXZ-SVzci3JqtHShfEP3ty-kaYMkVGWS9U,15160
+pathspec/tests/test_pathspec.py,sha256=UB_aETIpTxpuei79zI2_kbjI2XnM2tF_xTQOFD4IYL8,4845
+pathspec/tests/test_util.py,sha256=IjvDbKYyEnQOaa07ebx-qD4bb-YFSm3qm0PE-VhKUa0,7906
+pathspec-0.9.0.dist-info/LICENSE,sha256=-rPda9qyJvHAhjCx3ZF-Efy07F4eAg4sFvg6ChOGPoU,16726
+pathspec-0.9.0.dist-info/METADATA,sha256=nmGOFs7gDO9imfQOjDP2Mhu-NX1xK2DoDv4B7D37D80,12141
+pathspec-0.9.0.dist-info/WHEEL,sha256=8zNYZbwQSXoB9IfXOjPfeNwvAsALAjffgk27FqvCWbo,110
+pathspec-0.9.0.dist-info/top_level.txt,sha256=0NA6IbW6iCUZ4p402IRSyZpvx4yqoltHzMoAxVQHI1M,9
+pathspec-0.9.0.dist-info/RECORD,,
diff --git a/third_party/python/pathspec/pathspec-0.9.0.dist-info/WHEEL b/third_party/python/pathspec/pathspec-0.9.0.dist-info/WHEEL
new file mode 100644
index 0000000000..8b701e93c2
--- /dev/null
+++ b/third_party/python/pathspec/pathspec-0.9.0.dist-info/WHEEL
@@ -0,0 +1,6 @@
+Wheel-Version: 1.0
+Generator: bdist_wheel (0.33.6)
+Root-Is-Purelib: true
+Tag: py2-none-any
+Tag: py3-none-any
+
diff --git a/third_party/python/pathspec/pathspec-0.9.0.dist-info/top_level.txt b/third_party/python/pathspec/pathspec-0.9.0.dist-info/top_level.txt
new file mode 100644
index 0000000000..6486958df0
--- /dev/null
+++ b/third_party/python/pathspec/pathspec-0.9.0.dist-info/top_level.txt
@@ -0,0 +1 @@
+pathspec
diff --git a/third_party/python/pathspec/pathspec/__init__.py b/third_party/python/pathspec/pathspec/__init__.py
new file mode 100644
index 0000000000..790d0a33bb
--- /dev/null
+++ b/third_party/python/pathspec/pathspec/__init__.py
@@ -0,0 +1,43 @@
+# encoding: utf-8
+"""
+The *pathspec* package provides pattern matching for file paths. So far
+this only includes Git's wildmatch pattern matching (the style used for
+".gitignore" files).
+
+The following classes are imported and made available from the root of
+the `pathspec` package:
+
+- :class:`pathspec.pathspec.PathSpec`
+
+- :class:`pathspec.pattern.Pattern`
+
+- :class:`pathspec.pattern.RegexPattern`
+
+- :class:`pathspec.util.RecursionError`
+
+The following functions are also imported:
+
+- :func:`pathspec.util.iter_tree`
+- :func:`pathspec.util.lookup_pattern`
+- :func:`pathspec.util.match_files`
+"""
+from __future__ import unicode_literals
+
+from .pathspec import PathSpec
+from .pattern import Pattern, RegexPattern
+from .util import iter_tree, lookup_pattern, match_files, RecursionError
+
+from ._meta import (
+	__author__,
+	__copyright__,
+	__credits__,
+	__license__,
+	__version__,
+)
+
+# Load pattern implementations.
+from . import patterns
+
+# Expose `GitIgnorePattern` class in the root module for backward
+# compatibility with v0.4.
+from .patterns.gitwildmatch import GitIgnorePattern
diff --git a/third_party/python/pathspec/pathspec/_meta.py b/third_party/python/pathspec/pathspec/_meta.py
new file mode 100644
index 0000000000..ff4c3239a9
--- /dev/null
+++ b/third_party/python/pathspec/pathspec/_meta.py
@@ -0,0 +1,43 @@
+# encoding: utf-8
+"""
+This module contains the project meta-data.
+"""
+
+__author__ = "Caleb P. Burns"
+__copyright__ = "Copyright © 2013-2021 Caleb P. Burns"
+__credits__ = [
+	"dahlia <https://github.com/dahlia>",
+	"highb <https://github.com/highb>",
+	"029xue <https://github.com/029xue>",
+	"mikexstudios <https://github.com/mikexstudios>",
+	"nhumrich <https://github.com/nhumrich>",
+	"davidfraser <https://github.com/davidfraser>",
+	"demurgos <https://github.com/demurgos>",
+	"ghickman <https://github.com/ghickman>",
+	"nvie <https://github.com/nvie>",
+	"adrienverge <https://github.com/adrienverge>",
+	"AndersBlomdell <https://github.com/AndersBlomdell>",
+	"highb <https://github.com/highb>",
+	"thmxv <https://github.com/thmxv>",
+	"wimglenn <https://github.com/wimglenn>",
+	"hugovk <https://github.com/hugovk>",
+	"dcecile <https://github.com/dcecile>",
+	"mroutis <https://github.com/mroutis>",
+	"jdufresne <https://github.com/jdufresne>",
+	"groodt <https://github.com/groodt>",
+	"ftrofin <https://github.com/ftrofin>",
+	"pykong <https://github.com/pykong>",
+	"nhhollander <https://github.com/nhhollander>",
+	"KOLANICH <https://github.com/KOLANICH>",
+	"JonjonHays <https://github.com/JonjonHays>",
+	"Isaac0616 <https://github.com/Isaac0616>",
+	"SebastiaanZ <https://github.com/SebastiaanZ>",
+	"RoelAdriaans <https://github.com/RoelAdriaans>",
+	"raviselker <https://github.com/raviselker>",
+	"johanvergeer <https://github.com/johanvergeer>",
+	"danjer <https://github.com/danjer>",
+	"jhbuhrman <https://github.com/jhbuhrman>",
+	"WPDOrdina <https://github.com/WPDOrdina>",
+]
+__license__ = "MPL 2.0"
+__version__ = "0.9.0"
diff --git a/third_party/python/pathspec/pathspec/compat.py b/third_party/python/pathspec/pathspec/compat.py
new file mode 100644
index 0000000000..f5d17bf3ce
--- /dev/null
+++ b/third_party/python/pathspec/pathspec/compat.py
@@ -0,0 +1,41 @@
+# encoding: utf-8
+"""
+This module provides compatibility between Python 2 and 3. Hardly
+anything is used by this project to constitute including `six`_.
+
+.. _`six`: http://pythonhosted.org/six
+"""
+
+import sys
+
+if sys.version_info[0] < 3:
+	# Python 2.
+	unicode = unicode
+	string_types = (basestring,)
+
+	from collections import Iterable
+	from itertools import izip_longest
+
+	def iterkeys(mapping):
+		return mapping.iterkeys()
+
+else:
+	# Python 3.
+	unicode = str
+	string_types = (unicode,)
+
+	from collections.abc import Iterable
+	from itertools import zip_longest as izip_longest
+
+	def iterkeys(mapping):
+		return mapping.keys()
+
+try:
+	# Python 3.6+.
+	from collections.abc import Collection
+except ImportError:
+	# Python 2.7 - 3.5.
+	from collections import Container as Collection
+
+CollectionType = Collection
+IterableType = Iterable
diff --git a/third_party/python/pathspec/pathspec/pathspec.py b/third_party/python/pathspec/pathspec/pathspec.py
new file mode 100644
index 0000000000..ff40089d2c
--- /dev/null
+++ b/third_party/python/pathspec/pathspec/pathspec.py
@@ -0,0 +1,243 @@
+# encoding: utf-8
+"""
+This module provides an object oriented interface for pattern matching
+of files.
+"""
+
+try:
+	from typing import (
+		Any,
+		AnyStr,
+		Callable,
+		Iterable,
+		Iterator,
+		Optional,
+		Text,
+		Union)
+except ImportError:
+	pass
+
+try:
+	# Python 3.6+ type hints.
+	from os import PathLike
+	from typing import Collection
+except ImportError:
+	pass
+
+from . import util
+from .compat import (
+	CollectionType,
+	iterkeys,
+	izip_longest,
+	string_types)
+from .pattern import Pattern
+from .util import TreeEntry
+
+
+class PathSpec(object):
+	"""
+	The :class:`PathSpec` class is a wrapper around a list of compiled
+	:class:`.Pattern` instances.
+	"""
+
+	def __init__(self, patterns):
+		# type: (Iterable[Pattern]) -> None
+		"""
+		Initializes the :class:`PathSpec` instance.
+
+		*patterns* (:class:`~collections.abc.Collection` or :class:`~collections.abc.Iterable`)
+		yields each compiled pattern (:class:`.Pattern`).
+		"""
+
+		self.patterns = patterns if isinstance(patterns, CollectionType) else list(patterns)
+		"""
+		*patterns* (:class:`~collections.abc.Collection` of :class:`.Pattern`)
+		contains the compiled patterns.
+		"""
+
+	def __eq__(self, other):
+		# type: (PathSpec) -> bool
+		"""
+		Tests the equality of this path-spec with *other* (:class:`PathSpec`)
+		by comparing their :attr:`~PathSpec.patterns` attributes.
+		"""
+		if isinstance(other, PathSpec):
+			paired_patterns = izip_longest(self.patterns, other.patterns)
+			return all(a == b for a, b in paired_patterns)
+		else:
+			return NotImplemented
+
+	def __len__(self):
+		"""
+		Returns the number of compiled patterns this path-spec contains
+		(:class:`int`).
+		"""
+		return len(self.patterns)
+
+	def __add__(self, other):
+		# type: (PathSpec) -> PathSpec
+		"""
+		Combines the :attr:`Pathspec.patterns` patterns from two
+		:class:`PathSpec` instances.
+		"""
+		if isinstance(other, PathSpec):
+			return PathSpec(self.patterns + other.patterns)
+		else:
+			return NotImplemented
+
+	def __iadd__(self, other):
+		# type: (PathSpec) -> PathSpec
+		"""
+		Adds the :attr:`Pathspec.patterns` patterns from one :class:`PathSpec`
+		instance to this instance.
+		"""
+		if isinstance(other, PathSpec):
+			self.patterns += other.patterns
+			return self
+		else:
+			return NotImplemented
+
+	@classmethod
+	def from_lines(cls, pattern_factory, lines):
+		# type: (Union[Text, Callable[[AnyStr], Pattern]], Iterable[AnyStr]) -> PathSpec
+		"""
+		Compiles the pattern lines.
+
+		*pattern_factory* can be either the name of a registered pattern
+		factory (:class:`str`), or a :class:`~collections.abc.Callable` used
+		to compile patterns. It must accept an uncompiled pattern (:class:`str`)
+		and return the compiled pattern (:class:`.Pattern`).
+
+		*lines* (:class:`~collections.abc.Iterable`) yields each uncompiled
+		pattern (:class:`str`). This simply has to yield each line so it can
+		be a :class:`file` (e.g., from :func:`open` or :class:`io.StringIO`)
+		or the result from :meth:`str.splitlines`.
+
+		Returns the :class:`PathSpec` instance.
+		"""
+		if isinstance(pattern_factory, string_types):
+			pattern_factory = util.lookup_pattern(pattern_factory)
+		if not callable(pattern_factory):
+			raise TypeError("pattern_factory:{!r} is not callable.".format(pattern_factory))
+
+		if not util._is_iterable(lines):
+			raise TypeError("lines:{!r} is not an iterable.".format(lines))
+
+		patterns = [pattern_factory(line) for line in lines if line]
+		return cls(patterns)
+
+	def match_file(self, file, separators=None):
+		# type: (Union[Text, PathLike], Optional[Collection[Text]]) -> bool
+		"""
+		Matches the file to this path-spec.
+
+		*file* (:class:`str` or :class:`~pathlib.PurePath`) is the file path
+		to be matched against :attr:`self.patterns <PathSpec.patterns>`.
+
+		*separators* (:class:`~collections.abc.Collection` of :class:`str`)
+		optionally contains the path separators to normalize. See
+		:func:`~pathspec.util.normalize_file` for more information.
+
+		Returns :data:`True` if *file* matched; otherwise, :data:`False`.
+		"""
+		norm_file = util.normalize_file(file, separators=separators)
+		return util.match_file(self.patterns, norm_file)
+
+	def match_entries(self, entries, separators=None):
+		# type: (Iterable[TreeEntry], Optional[Collection[Text]]) -> Iterator[TreeEntry]
+		"""
+		Matches the entries to this path-spec.
+
+		*entries* (:class:`~collections.abc.Iterable` of :class:`~util.TreeEntry`)
+		contains the entries to be matched against :attr:`self.patterns <PathSpec.patterns>`.
+
+		*separators* (:class:`~collections.abc.Collection` of :class:`str`;
+		or :data:`None`) optionally contains the path separators to
+		normalize. See :func:`~pathspec.util.normalize_file` for more
+		information.
+
+		Returns the matched entries (:class:`~collections.abc.Iterator` of
+		:class:`~util.TreeEntry`).
+		"""
+		if not util._is_iterable(entries):
+			raise TypeError("entries:{!r} is not an iterable.".format(entries))
+
+		entry_map = util._normalize_entries(entries, separators=separators)
+		match_paths = util.match_files(self.patterns, iterkeys(entry_map))
+		for path in match_paths:
+			yield entry_map[path]
+
+	def match_files(self, files, separators=None):
+		# type: (Iterable[Union[Text, PathLike]], Optional[Collection[Text]]) -> Iterator[Union[Text, PathLike]]
+		"""
+		Matches the files to this path-spec.
+
+		*files* (:class:`~collections.abc.Iterable` of :class:`str; or
+		:class:`pathlib.PurePath`) contains the file paths to be matched
+		against :attr:`self.patterns <PathSpec.patterns>`.
+
+		*separators* (:class:`~collections.abc.Collection` of :class:`str`;
+		or :data:`None`) optionally contains the path separators to
+		normalize. See :func:`~pathspec.util.normalize_file` for more
+		information.
+
+		Returns the matched files (:class:`~collections.abc.Iterator` of
+		:class:`str` or :class:`pathlib.PurePath`).
+		"""
+		if not util._is_iterable(files):
+			raise TypeError("files:{!r} is not an iterable.".format(files))
+
+		file_map = util.normalize_files(files, separators=separators)
+		matched_files = util.match_files(self.patterns, iterkeys(file_map))
+		for norm_file in matched_files:
+			for orig_file in file_map[norm_file]:
+				yield orig_file
+
+	def match_tree_entries(self, root, on_error=None, follow_links=None):
+		# type: (Text, Optional[Callable], Optional[bool]) -> Iterator[TreeEntry]
+		"""
+		Walks the specified root path for all files and matches them to this
+		path-spec.
+
+		*root* (:class:`str`; or :class:`pathlib.PurePath`) is the root
+		directory to search.
+
+		*on_error* (:class:`~collections.abc.Callable` or :data:`None`)
+		optionally is the error handler for file-system exceptions. See
+		:func:`~pathspec.util.iter_tree_entries` for more information.
+
+		*follow_links* (:class:`bool` or :data:`None`) optionally is whether
+		to walk symbolic links that resolve to directories. See
+		:func:`~pathspec.util.iter_tree_files` for more information.
+
+		Returns the matched files (:class:`~collections.abc.Iterator` of
+		:class:`.TreeEntry`).
+		"""
+		entries = util.iter_tree_entries(root, on_error=on_error, follow_links=follow_links)
+		return self.match_entries(entries)
+
+	def match_tree_files(self, root, on_error=None, follow_links=None):
+		# type: (Text, Optional[Callable], Optional[bool]) -> Iterator[Text]
+		"""
+		Walks the specified root path for all files and matches them to this
+		path-spec.
+
+		*root* (:class:`str`; or :class:`pathlib.PurePath`) is the root
+		directory to search for files.
+
+		*on_error* (:class:`~collections.abc.Callable` or :data:`None`)
+		optionally is the error handler for file-system exceptions. See
+		:func:`~pathspec.util.iter_tree_files` for more information.
+
+		*follow_links* (:class:`bool` or :data:`None`) optionally is whether
+		to walk symbolic links that resolve to directories. See
+		:func:`~pathspec.util.iter_tree_files` for more information.
+
+		Returns the matched files (:class:`~collections.abc.Iterable` of
+		:class:`str`).
+		"""
+		files = util.iter_tree_files(root, on_error=on_error, follow_links=follow_links)
+		return self.match_files(files)
+
+	# Alias `match_tree_files()` as `match_tree()`.
+	match_tree = match_tree_files
diff --git a/third_party/python/pathspec/pathspec/pattern.py b/third_party/python/pathspec/pathspec/pattern.py
new file mode 100644
index 0000000000..c354c2632a
--- /dev/null
+++ b/third_party/python/pathspec/pathspec/pattern.py
@@ -0,0 +1,164 @@
+# encoding: utf-8
+"""
+This module provides the base definition for patterns.
+"""
+
+import re
+try:
+	from typing import (
+		AnyStr,
+		Iterable,
+		Iterator,
+		Optional,
+		Pattern as RegexHint,
+		Text,
+		Tuple,
+		Union)
+except ImportError:
+	pass
+
+from .compat import unicode
+
+
+class Pattern(object):
+	"""
+	The :class:`Pattern` class is the abstract definition of a pattern.
+	"""
+
+	# Make the class dict-less.
+	__slots__ = ('include',)
+
+	def __init__(self, include):
+		# type: (Optional[bool]) -> None
+		"""
+		Initializes the :class:`Pattern` instance.
+
+		*include* (:class:`bool` or :data:`None`) is whether the matched
+		files should be included (:data:`True`), excluded (:data:`False`),
+		or is a null-operation (:data:`None`).
+		"""
+
+		self.include = include
+		"""
+		*include* (:class:`bool` or :data:`None`) is whether the matched
+		files should be included (:data:`True`), excluded (:data:`False`),
+		or is a null-operation (:data:`None`).
+		"""
+
+	def match(self, files):
+		# type: (Iterable[Text]) -> Iterator[Text]
+		"""
+		Matches this pattern against the specified files.
+
+		*files* (:class:`~collections.abc.Iterable` of :class:`str`) contains
+		each file relative to the root directory (e.g., ``"relative/path/to/file"``).
+
+		Returns an :class:`~collections.abc.Iterable` yielding each matched
+		file path (:class:`str`).
+		"""
+		raise NotImplementedError("{}.{} must override match().".format(self.__class__.__module__, self.__class__.__name__))
+
+
+class RegexPattern(Pattern):
+	"""
+	The :class:`RegexPattern` class is an implementation of a pattern
+	using regular expressions.
+	"""
+
+	# Make the class dict-less.
+	__slots__ = ('regex',)
+
+	def __init__(self, pattern, include=None):
+		# type: (Union[AnyStr, RegexHint], Optional[bool]) -> None
+		"""
+		Initializes the :class:`RegexPattern` instance.
+
+		*pattern* (:class:`unicode`, :class:`bytes`, :class:`re.RegexObject`,
+		or :data:`None`) is the pattern to compile into a regular
+		expression.
+
+		*include* (:class:`bool` or :data:`None`) must be :data:`None`
+		unless *pattern* is a precompiled regular expression (:class:`re.RegexObject`)
+		in which case it is whether matched files should be included
+		(:data:`True`), excluded (:data:`False`), or is a null operation
+		(:data:`None`).
+
+			.. NOTE:: Subclasses do not need to support the *include*
+			   parameter.
+		"""
+
+		self.regex = None
+		"""
+		*regex* (:class:`re.RegexObject`) is the regular expression for the
+		pattern.
+		"""
+
+		if isinstance(pattern, (unicode, bytes)):
+			assert include is None, "include:{!r} must be null when pattern:{!r} is a string.".format(include, pattern)
+			regex, include = self.pattern_to_regex(pattern)
+			# NOTE: Make sure to allow a null regular expression to be
+			# returned for a null-operation.
+			if include is not None:
+				regex = re.compile(regex)
+
+		elif pattern is not None and hasattr(pattern, 'match'):
+			# Assume pattern is a precompiled regular expression.
+			# - NOTE: Used specified *include*.
+			regex = pattern
+
+		elif pattern is None:
+			# NOTE: Make sure to allow a null pattern to be passed for a
+			# null-operation.
+			assert include is None, "include:{!r} must be null when pattern:{!r} is null.".format(include, pattern)
+
+		else:
+			raise TypeError("pattern:{!r} is not a string, RegexObject, or None.".format(pattern))
+
+		super(RegexPattern, self).__init__(include)
+		self.regex = regex
+
+	def __eq__(self, other):
+		# type: (RegexPattern) -> bool
+		"""
+		Tests the equality of this regex pattern with *other* (:class:`RegexPattern`)
+		by comparing their :attr:`~Pattern.include` and :attr:`~RegexPattern.regex`
+		attributes.
+		"""
+		if isinstance(other, RegexPattern):
+			return self.include == other.include and self.regex == other.regex
+		else:
+			return NotImplemented
+
+	def match(self, files):
+		# type: (Iterable[Text]) -> Iterable[Text]
+		"""
+		Matches this pattern against the specified files.
+
+		*files* (:class:`~collections.abc.Iterable` of :class:`str`)
+		contains each file relative to the root directory (e.g., "relative/path/to/file").
+
+		Returns an :class:`~collections.abc.Iterable` yielding each matched
+		file path (:class:`str`).
+		"""
+		if self.include is not None:
+			for path in files:
+				if self.regex.match(path) is not None:
+					yield path
+
+	@classmethod
+	def pattern_to_regex(cls, pattern):
+		# type: (Text) -> Tuple[Text, bool]
+		"""
+		Convert the pattern into an uncompiled regular expression.
+
+		*pattern* (:class:`str`) is the pattern to convert into a regular
+		expression.
+
+		Returns the uncompiled regular expression (:class:`str` or :data:`None`),
+		and whether matched files should be included (:data:`True`),
+		excluded (:data:`False`), or is a null-operation (:data:`None`).
+
+			.. NOTE:: The default implementation simply returns *pattern* and
+			   :data:`True`.
+		"""
+		return pattern, True
diff --git a/third_party/python/pathspec/pathspec/patterns/__init__.py b/third_party/python/pathspec/pathspec/patterns/__init__.py
new file mode 100644
index 0000000000..1a0d55ec74
--- /dev/null
+++ b/third_party/python/pathspec/pathspec/patterns/__init__.py
@@ -0,0 +1,8 @@
+# encoding: utf-8
+"""
+The *pathspec.patterns* package contains the pattern matching
+implementations.
+"""
+
+# Load pattern implementations.
+from .gitwildmatch import GitWildMatchPattern
diff --git a/third_party/python/pathspec/pathspec/patterns/gitwildmatch.py b/third_party/python/pathspec/pathspec/patterns/gitwildmatch.py
new file mode 100644
index 0000000000..afd8f6b4cf
--- /dev/null
+++ b/third_party/python/pathspec/pathspec/patterns/gitwildmatch.py
@@ -0,0 +1,400 @@
+# encoding: utf-8
+"""
+This module implements Git's wildmatch pattern matching which itself is
+derived from Rsync's wildmatch. Git uses wildmatch for its ".gitignore"
+files.
+"""
+from __future__ import unicode_literals
+
+import re
+import warnings
+try:
+	from typing import (
+		AnyStr,
+		Optional,
+		Text,
+		Tuple)
+except ImportError:
+	pass
+
+from .. import util
+from ..compat import unicode
+from ..pattern import RegexPattern
+
+#: The encoding to use when parsing a byte string pattern.
+_BYTES_ENCODING = 'latin1'
+
+
+class GitWildMatchPatternError(ValueError):
+	"""
+	The :class:`GitWildMatchPatternError` indicates an invalid git wild match
+	pattern.
+	"""
+	pass
+
+
+class GitWildMatchPattern(RegexPattern):
+	"""
+	The :class:`GitWildMatchPattern` class represents a compiled Git
+	wildmatch pattern.
+	"""
+
+	# Keep the dict-less class hierarchy.
+	__slots__ = ()
+
+	@classmethod
+	def pattern_to_regex(cls, pattern):
+		# type: (AnyStr) -> Tuple[Optional[AnyStr], Optional[bool]]
+		"""
+		Convert the pattern into a regular expression.
+
+		*pattern* (:class:`unicode` or :class:`bytes`) is the pattern to
+		convert into a regular expression.
+
+		Returns the uncompiled regular expression (:class:`unicode`, :class:`bytes`,
+		or :data:`None`), and whether matched files should be included
+		(:data:`True`), excluded (:data:`False`), or if it is a
+		null-operation (:data:`None`).
+		"""
+		if isinstance(pattern, unicode):
+			return_type = unicode
+		elif isinstance(pattern, bytes):
+			return_type = bytes
+			pattern = pattern.decode(_BYTES_ENCODING)
+		else:
+			raise TypeError("pattern:{!r} is not a unicode or byte string.".format(pattern))
+
+		original_pattern = pattern
+		pattern = pattern.strip()
+
+		if pattern.startswith('#'):
+			# A pattern starting with a hash ('#') serves as a comment
+			# (neither includes nor excludes files). Escape the hash with a
+			# back-slash to match a literal hash (i.e., '\#').
+			regex = None
+			include = None
+
+		elif pattern == '/':
+			# EDGE CASE: According to `git check-ignore` (v2.4.1), a single
+			# '/' does not match any file.
+			regex = None
+			include = None
+
+		elif pattern:
+			if pattern.startswith('!'):
+				# A pattern starting with an exclamation mark ('!') negates the
+				# pattern (exclude instead of include). Escape the exclamation
+				# mark with a back-slash to match a literal exclamation mark
+				# (i.e., '\!').
+				include = False
+				# Remove leading exclamation mark.
+				pattern = pattern[1:]
+			else:
+				include = True
+
+			if pattern.startswith('\\'):
+				# Remove leading back-slash escape for escaped hash ('#') or
+				# exclamation mark ('!').
+				pattern = pattern[1:]
+
+			# Allow a regex override for edge cases that cannot be handled
+			# through normalization.
+			override_regex = None
+
+			# Split pattern into segments.
+			pattern_segs = pattern.split('/')
+
+			# Normalize pattern to make processing easier.
+
+			# EDGE CASE: Deal with duplicate double-asterisk sequences.
+			# Collapse each sequence down to one double-asterisk. Iterate over
+			# the segments in reverse and remove the duplicate double
+			# asterisks as we go.
+			for i in range(len(pattern_segs) - 1, 0, -1):
+				prev = pattern_segs[i-1]
+				seg = pattern_segs[i]
+				if prev == '**' and seg == '**':
+					del pattern_segs[i]
+
+			if len(pattern_segs) == 2 and pattern_segs[0] == '**' and not pattern_segs[1]:
+				# EDGE CASE: The '**/' pattern should match everything except
+				# individual files in the root directory. This case cannot be
+				# adequately handled through normalization. Use the override.
+				override_regex = '^.+/.*$'
+
+			if not pattern_segs[0]:
+				# A pattern beginning with a slash ('/') will only match paths
+				# directly on the root directory instead of any descendant
+				# paths. So, remove empty first segment to make pattern relative
+				# to root.
+				del pattern_segs[0]
+
+			elif len(pattern_segs) == 1 or (len(pattern_segs) == 2 and not pattern_segs[1]):
+				# A single pattern without a beginning slash ('/') will match
+				# any descendant path. This is equivalent to "**/{pattern}". So,
+				# prepend with double-asterisks to make pattern relative to
+				# root.
+				# EDGE CASE: This also holds for a single pattern with a
+				# trailing slash (e.g. dir/).
+				if pattern_segs[0] != '**':
+					pattern_segs.insert(0, '**')
+
+			else:
+				# EDGE CASE: A pattern without a beginning slash ('/') but
+				# contains at least one prepended directory (e.g.
+				# "dir/{pattern}") should not match "**/dir/{pattern}",
+				# according to `git check-ignore` (v2.4.1).
+				pass
+
+			if not pattern_segs:
+				# After resolving the edge cases, we end up with no
+				# pattern at all. This must be because the pattern is
+				# invalid.
+				raise GitWildMatchPatternError("Invalid git pattern: %r" % (original_pattern,))
+
+			if not pattern_segs[-1] and len(pattern_segs) > 1:
+				# A pattern ending with a slash ('/') will match all
+				# descendant paths if it is a directory but not if it is a
+				# regular file. This is equivalent to "{pattern}/**". So, set
+				# last segment to a double-asterisk to include all
+				# descendants.
+				pattern_segs[-1] = '**'
+
+			if override_regex is None:
+				# Build regular expression from pattern.
+				output = ['^']
+				need_slash = False
+				end = len(pattern_segs) - 1
+				for i, seg in enumerate(pattern_segs):
+					if seg == '**':
+						if i == 0 and i == end:
+							# A pattern consisting solely of double-asterisks ('**')
+							# will match every path.
+							output.append('.+')
+						elif i == 0:
+							# A normalized pattern beginning with double-asterisks
+							# ('**') will match any leading path segments.
+							output.append('(?:.+/)?')
+							need_slash = False
+						elif i == end:
+							# A normalized pattern ending with double-asterisks ('**')
+							# will match any trailing path segments.
+							output.append('/.*')
+						else:
+							# A pattern with inner double-asterisks ('**') will match
+							# multiple (or zero) inner path segments.
+							output.append('(?:/.+)?')
+							need_slash = True
+
+					elif seg == '*':
+						# Match single path segment.
+						if need_slash:
+							output.append('/')
+						output.append('[^/]+')
+						need_slash = True
+
+					else:
+						# Match segment glob pattern.
+						if need_slash:
+							output.append('/')
+
+						output.append(cls._translate_segment_glob(seg))
+						if i == end and include is True:
+							# A pattern ending without a slash ('/') will match a file
+							# or a directory (with paths underneath it). E.g., "foo"
+							# matches "foo", "foo/bar", "foo/bar/baz", etc.
+							# EDGE CASE: However, this does not hold for exclusion cases
+							# according to `git check-ignore` (v2.4.1).
+							output.append('(?:/.*)?')
+
+						need_slash = True
+
+				output.append('$')
+				regex = ''.join(output)
+
+			else:
+				# Use regex override.
+				regex = override_regex
+
+		else:
+			# A blank pattern is a null-operation (neither includes nor
+			# excludes files).
+			regex = None
+			include = None
+
+		if regex is not None and return_type is bytes:
+			regex = regex.encode(_BYTES_ENCODING)
+
+		return regex, include
+
+	@staticmethod
+	def _translate_segment_glob(pattern):
+		# type: (Text) -> Text
+		"""
+		Translates the glob pattern to a regular expression. This is used in
+		the constructor to translate a path segment glob pattern to its
+		corresponding regular expression.
+
+		*pattern* (:class:`str`) is the glob pattern.
+
+		Returns the regular expression (:class:`str`).
+		"""
+		# NOTE: This is derived from `fnmatch.translate()` and is similar to
+		# the POSIX function `fnmatch()` with the `FNM_PATHNAME` flag set.
+
+		escape = False
+		regex = ''
+		i, end = 0, len(pattern)
+		while i < end:
+			# Get next character.
+			char = pattern[i]
+			i += 1
+
+			if escape:
+				# Escape the character.
+				escape = False
+				regex += re.escape(char)
+
+			elif char == '\\':
+				# Escape character, escape next character.
+				escape = True
+
+			elif char == '*':
+				# Multi-character wildcard. Match any string (except slashes),
+				# including an empty string.
+				regex += '[^/]*'
+
+			elif char == '?':
+				# Single-character wildcard. Match any single character (except
+				# a slash).
+				regex += '[^/]'
+
+			elif char == '[':
+				# Bracket expression wildcard. Except for the beginning
+				# exclamation mark, the whole bracket expression can be used
+				# directly as regex but we have to find where the expression
+				# ends.
+				# - "[][!]" matches ']', '[' and '!'.
+				# - "[]-]" matches ']' and '-'.
+				# - "[!]a-]" matches any character except ']', 'a' and '-'.
+				j = i
+				# Pass brack expression negation.
+				if j < end and pattern[j] == '!':
+					j += 1
+				# Pass first closing bracket if it is at the beginning of the
+				# expression.
+				if j < end and pattern[j] == ']':
+					j += 1
+				# Find closing bracket. Stop once we reach the end or find it.
+				while j < end and pattern[j] != ']':
+					j += 1
+
+				if j < end:
+					# Found end of bracket expression. Increment j to be one past
+					# the closing bracket:
+					#
+					#  [...]
+					#   ^   ^
+					#   i   j
+					#
+					j += 1
+					expr = '['
+
+					if pattern[i] == '!':
+						# Braket expression needs to be negated.
+						expr += '^'
+						i += 1
+					elif pattern[i] == '^':
+						# POSIX declares that the regex bracket expression negation
+						# "[^...]" is undefined in a glob pattern. Python's
+						# `fnmatch.translate()` escapes the caret ('^') as a
+						# literal. To maintain consistency with undefined behavior,
+						# I am escaping the '^' as well.
+						expr += '\\^'
+						i += 1
+
+					# Build regex bracket expression. Escape slashes so they are
+					# treated as literal slashes by regex as defined by POSIX.
+					expr += pattern[i:j].replace('\\', '\\\\')
+
+					# Add regex bracket expression to regex result.
+					regex += expr
+
+					# Set i to one past the closing bracket.
+					i = j
+
+				else:
+					# Failed to find closing bracket, treat opening bracket as a
+					# bracket literal instead of as an expression.
+					regex += '\\['
+
+			else:
+				# Regular character, escape it for regex.
+				regex += re.escape(char)
+
+		return regex
+
+	@staticmethod
+	def escape(s):
+		# type: (AnyStr) -> AnyStr
+		"""
+		Escape special characters in the given string.
+
+		*s* (:class:`unicode` or :class:`bytes`) a filename or a string
+		that you want to escape, usually before adding it to a `.gitignore`
+
+		Returns the escaped string (:class:`unicode` or :class:`bytes`)
+		"""
+		if isinstance(s, unicode):
+			return_type = unicode
+			string = s
+		elif isinstance(s, bytes):
+			return_type = bytes
+			string = s.decode(_BYTES_ENCODING)
+		else:
+			raise TypeError("s:{!r} is not a unicode or byte string.".format(s))
+
+		# Reference: https://git-scm.com/docs/gitignore#_pattern_format
+		meta_characters = r"[]!*#?"
+
+		out_string = "".join("\\" + x if x in meta_characters else x for x in string)
+
+		if return_type is bytes:
+			return out_string.encode(_BYTES_ENCODING)
+		else:
+			return out_string
+
+util.register_pattern('gitwildmatch', GitWildMatchPattern)
+
+
+class GitIgnorePattern(GitWildMatchPattern):
+	"""
+	The :class:`GitIgnorePattern` class is deprecated by :class:`GitWildMatchPattern`.
+	This class only exists to maintain compatibility with v0.4.
+	"""
+
+	def __init__(self, *args, **kw):
+		"""
+		Warn about deprecation.
+		"""
+		self._deprecated()
+		super(GitIgnorePattern, self).__init__(*args, **kw)
+
+	@staticmethod
+	def _deprecated():
+		"""
+		Warn about deprecation.
+		"""
+		warnings.warn("GitIgnorePattern ('gitignore') is deprecated. Use GitWildMatchPattern ('gitwildmatch') instead.", DeprecationWarning, stacklevel=3)
+
+	@classmethod
+	def pattern_to_regex(cls, *args, **kw):
+		"""
+		Warn about deprecation.
+		"""
+		cls._deprecated()
+		return super(GitIgnorePattern, cls).pattern_to_regex(*args, **kw)
+
+# Register `GitIgnorePattern` as "gitignore" for backward compatibility
+# with v0.4.
+util.register_pattern('gitignore', GitIgnorePattern)
diff --git a/third_party/python/pathspec/pathspec/util.py b/third_party/python/pathspec/pathspec/util.py
new file mode 100644
index 0000000000..64a5dea9db
--- /dev/null
+++ b/third_party/python/pathspec/pathspec/util.py
@@ -0,0 +1,665 @@
+# encoding: utf-8
+"""
+This module provides utility methods for dealing with path-specs.
+"""
+
+import os
+import os.path
+import posixpath
+import stat
+try:
+	from typing import (
+		Any,
+		AnyStr,
+		Callable,
+		Dict,
+		Iterable,
+		Iterator,
+		List,
+		Optional,
+		Sequence,
+		Set,
+		Text,
+		Union)
+except ImportError:
+	pass
+try:
+	# Python 3.6+ type hints.
+	from os import PathLike
+	from typing import Collection
+except ImportError:
+	pass
+
+from .compat import (
+	CollectionType,
+	IterableType,
+	string_types,
+	unicode)
+from .pattern import Pattern
+
+NORMALIZE_PATH_SEPS = [sep for sep in [os.sep, os.altsep] if sep and sep != posixpath.sep]
+"""
+*NORMALIZE_PATH_SEPS* (:class:`list` of :class:`str`) contains the path
+separators that need to be normalized to the POSIX separator for the
+current operating system. The separators are determined by examining
+:data:`os.sep` and :data:`os.altsep`.
+"""
+
+_registered_patterns = {}
+"""
+*_registered_patterns* (:class:`dict`) maps a name (:class:`str`) to the
+registered pattern factory (:class:`~collections.abc.Callable`).
+"""
+
+
+def detailed_match_files(patterns, files, all_matches=None):
+	# type: (Iterable[Pattern], Iterable[Text], Optional[bool]) -> Dict[Text, 'MatchDetail']
+	"""
+	Matches the files to the patterns, and returns which patterns matched
+	the files.
+
+	*patterns* (:class:`~collections.abc.Iterable` of :class:`~pathspec.pattern.Pattern`)
+	contains the patterns to use.
+
+	*files* (:class:`~collections.abc.Iterable` of :class:`str`) contains
+	the normalized file paths to be matched against *patterns*.
+
+	*all_matches* (:class:`boot` or :data:`None`) is whether to return all
+	matches patterns (:data:`True`), or only the last matched pattern
+	(:data:`False`). Default is :data:`None` for :data:`False`.
+
+	Returns the matched files (:class:`dict`) which maps each matched file
+	(:class:`str`) to the patterns that matched in order (:class:`.MatchDetail`).
+	"""
+	all_files = files if isinstance(files, CollectionType) else list(files)
+	return_files = {}
+	for pattern in patterns:
+		if pattern.include is not None:
+			result_files = pattern.match(all_files)
+			if pattern.include:
+				# Add files and record pattern.
+				for result_file in result_files:
+					if result_file in return_files:
+						if all_matches:
+							return_files[result_file].patterns.append(pattern)
+						else:
+							return_files[result_file].patterns[0] = pattern
+					else:
+						return_files[result_file] = MatchDetail([pattern])
+
+			else:
+				# Remove files.
+				for file in result_files:
+					del return_files[file]
+
+	return return_files
+
+
+def _is_iterable(value):
+	# type: (Any) -> bool
+	"""
+	Check whether the value is an iterable (excludes strings).
+
+	*value* is the value to check,
+
+	Returns whether *value* is a iterable (:class:`bool`).
+	"""
+	return isinstance(value, IterableType) and not isinstance(value, (unicode, bytes))
+
+
+def iter_tree_entries(root, on_error=None, follow_links=None):
+	# type: (Text, Optional[Callable], Optional[bool]) -> Iterator['TreeEntry']
+	"""
+	Walks the specified directory for all files and directories.
+
+	*root* (:class:`str`) is the root directory to search.
+
+	*on_error* (:class:`~collections.abc.Callable` or :data:`None`)
+	optionally is the error handler for file-system exceptions. It will be
+	called with the exception (:exc:`OSError`). Reraise the exception to
+	abort the walk. Default is :data:`None` to ignore file-system
+	exceptions.
+
+	*follow_links* (:class:`bool` or :data:`None`) optionally is whether
+	to walk symbolic links that resolve to directories. Default is
+	:data:`None` for :data:`True`.
+
+	Raises :exc:`RecursionError` if recursion is detected.
+
+	Returns an :class:`~collections.abc.Iterator` yielding each file or
+	directory entry (:class:`.TreeEntry`) relative to *root*.
+	"""
+	if on_error is not None and not callable(on_error):
+		raise TypeError("on_error:{!r} is not callable.".format(on_error))
+
+	if follow_links is None:
+		follow_links = True
+
+	for entry in _iter_tree_entries_next(os.path.abspath(root), '', {}, on_error, follow_links):
+		yield entry
+
+
+def iter_tree_files(root, on_error=None, follow_links=None):
+	# type: (Text, Optional[Callable], Optional[bool]) -> Iterator[Text]
+	"""
+	Walks the specified directory for all files.
+
+	*root* (:class:`str`) is the root directory to search for files.
+
+	*on_error* (:class:`~collections.abc.Callable` or :data:`None`)
+	optionally is the error handler for file-system exceptions. It will be
+	called with the exception (:exc:`OSError`). Reraise the exception to
+	abort the walk. Default is :data:`None` to ignore file-system
+	exceptions.
+
+	*follow_links* (:class:`bool` or :data:`None`) optionally is whether
+	to walk symbolic links that resolve to directories. Default is
+	:data:`None` for :data:`True`.
+
+	Raises :exc:`RecursionError` if recursion is detected.
+
+	Returns an :class:`~collections.abc.Iterator` yielding the path to
+	each file (:class:`str`) relative to *root*.
+	"""
+	if on_error is not None and not callable(on_error):
+		raise TypeError("on_error:{!r} is not callable.".format(on_error))
+
+	if follow_links is None:
+		follow_links = True
+
+	for entry in _iter_tree_entries_next(os.path.abspath(root), '', {}, on_error, follow_links):
+		if not entry.is_dir(follow_links):
+			yield entry.path
+
+
+# Alias `iter_tree_files()` as `iter_tree()`.
+iter_tree = iter_tree_files
+
+
+def _iter_tree_entries_next(root_full, dir_rel, memo, on_error, follow_links):
+	# type: (Text, Text, Dict[Text, Text], Callable, bool) -> Iterator['TreeEntry']
+	"""
+	Scan the directory for all descendant files.
+
+	*root_full* (:class:`str`) the absolute path to the root directory.
+
+	*dir_rel* (:class:`str`) the path to the directory to scan relative to
+	*root_full*.
+
+	*memo* (:class:`dict`) keeps track of ancestor directories
+	encountered. Maps each ancestor real path (:class:`str`) to relative
+	path (:class:`str`).
+
+	*on_error* (:class:`~collections.abc.Callable` or :data:`None`)
+	optionally is the error handler for file-system exceptions.
+
+	*follow_links* (:class:`bool`) is whether to walk symbolic links that
+	resolve to directories.
+
+	Yields each entry (:class:`.TreeEntry`).
+	"""
+	dir_full = os.path.join(root_full, dir_rel)
+	dir_real = os.path.realpath(dir_full)
+
+	# Remember each encountered ancestor directory and its canonical
+	# (real) path. If a canonical path is encountered more than once,
+	# recursion has occurred.
+	if dir_real not in memo:
+		memo[dir_real] = dir_rel
+	else:
+		raise RecursionError(real_path=dir_real, first_path=memo[dir_real], second_path=dir_rel)
+
+	for node_name in os.listdir(dir_full):
+		node_rel = os.path.join(dir_rel, node_name)
+		node_full = os.path.join(root_full, node_rel)
+
+		# Inspect child node.
+		try:
+			node_lstat = os.lstat(node_full)
+		except OSError as e:
+			if on_error is not None:
+				on_error(e)
+			continue
+
+		if stat.S_ISLNK(node_lstat.st_mode):
+			# Child node is a link, inspect the target node.
+			is_link = True
+			try:
+				node_stat = os.stat(node_full)
+			except OSError as e:
+				if on_error is not None:
+					on_error(e)
+				continue
+		else:
+			is_link = False
+			node_stat = node_lstat
+
+		if stat.S_ISDIR(node_stat.st_mode) and (follow_links or not is_link):
+			# Child node is a directory, recurse into it and yield its
+			# descendant files.
+			yield TreeEntry(node_name, node_rel, node_lstat, node_stat)
+
+			for entry in _iter_tree_entries_next(root_full, node_rel, memo, on_error, follow_links):
+				yield entry
+
+		elif stat.S_ISREG(node_stat.st_mode) or is_link:
+			# Child node is either a file or an unfollowed link, yield it.
+			yield TreeEntry(node_name, node_rel, node_lstat, node_stat)
+
+	# NOTE: Make sure to remove the canonical (real) path of the directory
+	# from the ancestors memo once we are done with it. This allows the
+	# same directory to appear multiple times. If this is not done, the
+	# second occurrence of the directory will be incorrectly interpreted
+	# as a recursion. See <https://github.com/cpburnz/python-path-specification/pull/7>.
+	del memo[dir_real]
+
+
+def lookup_pattern(name):
+	# type: (Text) -> Callable[[AnyStr], Pattern]
+	"""
+	Lookups a registered pattern factory by name.
+
+	*name* (:class:`str`) is the name of the pattern factory.
+
+	Returns the registered pattern factory (:class:`~collections.abc.Callable`).
+	If no pattern factory is registered, raises :exc:`KeyError`.
+	"""
+	return _registered_patterns[name]
+
+
+def match_file(patterns, file):
+	# type: (Iterable[Pattern], Text) -> bool
+	"""
+	Matches the file to the patterns.
+
+	*patterns* (:class:`~collections.abc.Iterable` of :class:`~pathspec.pattern.Pattern`)
+	contains the patterns to use.
+
+	*file* (:class:`str`) is the normalized file path to be matched
+	against *patterns*.
+
+	Returns :data:`True` if *file* matched; otherwise, :data:`False`.
+	"""
+	matched = False
+	for pattern in patterns:
+		if pattern.include is not None:
+			if file in pattern.match((file,)):
+				matched = pattern.include
+	return matched
+
+
+def match_files(patterns, files):
+	# type: (Iterable[Pattern], Iterable[Text]) -> Set[Text]
+	"""
+	Matches the files to the patterns.
+
+	*patterns* (:class:`~collections.abc.Iterable` of :class:`~pathspec.pattern.Pattern`)
+	contains the patterns to use.
+
+	*files* (:class:`~collections.abc.Iterable` of :class:`str`) contains
+	the normalized file paths to be matched against *patterns*.
+
+	Returns the matched files (:class:`set` of :class:`str`).
+	"""
+	all_files = files if isinstance(files, CollectionType) else list(files)
+	return_files = set()
+	for pattern in patterns:
+		if pattern.include is not None:
+			result_files = pattern.match(all_files)
+			if pattern.include:
+				return_files.update(result_files)
+			else:
+				return_files.difference_update(result_files)
+	return return_files
+
+
+def _normalize_entries(entries, separators=None):
+	# type: (Iterable['TreeEntry'], Optional[Collection[Text]]) -> Dict[Text, 'TreeEntry']
+	"""
+	Normalizes the entry paths to use the POSIX path separator.
+
+	*entries* (:class:`~collections.abc.Iterable` of :class:`.TreeEntry`)
+	contains the entries to be normalized.
+
+	*separators* (:class:`~collections.abc.Collection` of :class:`str`; or
+	:data:`None`) optionally contains the path separators to normalize.
+	See :func:`normalize_file` for more information.
+
+	Returns a :class:`dict` mapping the each normalized file path (:class:`str`)
+	to the entry (:class:`.TreeEntry`)
+	"""
+	norm_files = {}
+	for entry in entries:
+		norm_files[normalize_file(entry.path, separators=separators)] = entry
+	return norm_files
+
+
+def normalize_file(file, separators=None):
+	# type: (Union[Text, PathLike], Optional[Collection[Text]]) -> Text
+	"""
+	Normalizes the file path to use the POSIX path separator (i.e.,
+	``'/'``), and make the paths relative (remove leading ``'/'``).
+
+	*file* (:class:`str` or :class:`pathlib.PurePath`) is the file path.
+
+	*separators* (:class:`~collections.abc.Collection` of :class:`str`; or
+	:data:`None`) optionally contains the path separators to normalize.
+	This does not need to include the POSIX path separator (``'/'``), but
+	including it will not affect the results. Default is :data:`None` for
+	:data:`NORMALIZE_PATH_SEPS`. To prevent normalization, pass an empty
+	container (e.g., an empty tuple ``()``).
+
+	Returns the normalized file path (:class:`str`).
+	"""
+	# Normalize path separators.
+	if separators is None:
+		separators = NORMALIZE_PATH_SEPS
+
+	# Convert path object to string.
+	norm_file = str(file)
+
+	for sep in separators:
+		norm_file = norm_file.replace(sep, posixpath.sep)
+
+	if norm_file.startswith('/'):
+		# Make path relative.
+		norm_file = norm_file[1:]
+
+	elif norm_file.startswith('./'):
+		# Remove current directory prefix.
+		norm_file = norm_file[2:]
+
+	return norm_file
+
+
+def normalize_files(files, separators=None):
+	# type: (Iterable[Union[str, PathLike]], Optional[Collection[Text]]) -> Dict[Text, List[Union[str, PathLike]]]
+	"""
+	Normalizes the file paths to use the POSIX path separator.
+
+	*files* (:class:`~collections.abc.Iterable` of :class:`str` or
+	:class:`pathlib.PurePath`) contains the file paths to be normalized.
+
+	*separators* (:class:`~collections.abc.Collection` of :class:`str`; or
+	:data:`None`) optionally contains the path separators to normalize.
+	See :func:`normalize_file` for more information.
+
+	Returns a :class:`dict` mapping the each normalized file path
+	(:class:`str`) to the original file paths (:class:`list` of
+	:class:`str` or :class:`pathlib.PurePath`).
+	"""
+	norm_files = {}
+	for path in files:
+		norm_file = normalize_file(path, separators=separators)
+		if norm_file in norm_files:
+			norm_files[norm_file].append(path)
+		else:
+			norm_files[norm_file] = [path]
+
+	return norm_files
+
+
+def register_pattern(name, pattern_factory, override=None):
+	# type: (Text, Callable[[AnyStr], Pattern], Optional[bool]) -> None
+	"""
+	Registers the specified pattern factory.
+
+	*name* (:class:`str`) is the name to register the pattern factory
+	under.
+
+	*pattern_factory* (:class:`~collections.abc.Callable`) is used to
+	compile patterns. It must accept an uncompiled pattern (:class:`str`)
+	and return the compiled pattern (:class:`.Pattern`).
+
+	*override* (:class:`bool` or :data:`None`) optionally is whether to
+	allow overriding an already registered pattern under the same name
+	(:data:`True`), instead of raising an :exc:`AlreadyRegisteredError`
+	(:data:`False`). Default is :data:`None` for :data:`False`.
+	"""
+	if not isinstance(name, string_types):
+		raise TypeError("name:{!r} is not a string.".format(name))
+	if not callable(pattern_factory):
+		raise TypeError("pattern_factory:{!r} is not callable.".format(pattern_factory))
+	if name in _registered_patterns and not override:
+		raise AlreadyRegisteredError(name, _registered_patterns[name])
+	_registered_patterns[name] = pattern_factory
+
+
+class AlreadyRegisteredError(Exception):
+	"""
+	The :exc:`AlreadyRegisteredError` exception is raised when a pattern
+	factory is registered under a name already in use.
+	"""
+
+	def __init__(self, name, pattern_factory):
+		# type: (Text, Callable[[AnyStr], Pattern]) -> None
+		"""
+		Initializes the :exc:`AlreadyRegisteredError` instance.
+
+		*name* (:class:`str`) is the name of the registered pattern.
+
+		*pattern_factory* (:class:`~collections.abc.Callable`) is the
+		registered pattern factory.
+		"""
+		super(AlreadyRegisteredError, self).__init__(name, pattern_factory)
+
+	@property
+	def message(self):
+		# type: () -> Text
+		"""
+		*message* (:class:`str`) is the error message.
+		"""
+		return "{name!r} is already registered for pattern factory:{pattern_factory!r}.".format(
+			name=self.name,
+			pattern_factory=self.pattern_factory,
+		)
+
+	@property
+	def name(self):
+		# type: () -> Text
+		"""
+		*name* (:class:`str`) is the name of the registered pattern.
+		"""
+		return self.args[0]
+
+	@property
+	def pattern_factory(self):
+		# type: () -> Callable[[AnyStr], Pattern]
+		"""
+		*pattern_factory* (:class:`~collections.abc.Callable`) is the
+		registered pattern factory.
+		"""
+		return self.args[1]
+
+
+class RecursionError(Exception):
+	"""
+	The :exc:`RecursionError` exception is raised when recursion is
+	detected.
+	"""
+
+	def __init__(self, real_path, first_path, second_path):
+		# type: (Text, Text, Text) -> None
+		"""
+		Initializes the :exc:`RecursionError` instance.
+
+		*real_path* (:class:`str`) is the real path that recursion was
+		encountered on.
+
+		*first_path* (:class:`str`) is the first path encountered for
+		*real_path*.
+
+		*second_path* (:class:`str`) is the second path encountered for
+		*real_path*.
+		"""
+		super(RecursionError, self).__init__(real_path, first_path, second_path)
+
+	@property
+	def first_path(self):
+		# type: () -> Text
+		"""
+		*first_path* (:class:`str`) is the first path encountered for
+		:attr:`self.real_path <RecursionError.real_path>`.
+		"""
+		return self.args[1]
+
+	@property
+	def message(self):
+		# type: () -> Text
+		"""
+		*message* (:class:`str`) is the error message.
+		"""
+		return "Real path {real!r} was encountered at {first!r} and then {second!r}.".format(
+			real=self.real_path,
+			first=self.first_path,
+			second=self.second_path,
+		)
+
+	@property
+	def real_path(self):
+		# type: () -> Text
+		"""
+		*real_path* (:class:`str`) is the real path that recursion was
+		encountered on.
+		"""
+		return self.args[0]
+
+	@property
+	def second_path(self):
+		# type: () -> Text
+		"""
+		*second_path* (:class:`str`) is the second path encountered for
+		:attr:`self.real_path <RecursionError.real_path>`.
+		"""
+		return self.args[2]
+
+
+class MatchDetail(object):
+	"""
+	The :class:`.MatchDetail` class contains information about
+	"""
+
+	#: Make the class dict-less.
+	__slots__ = ('patterns',)
+
+	def __init__(self, patterns):
+		# type: (Sequence[Pattern]) -> None
+		"""
+		Initialize the :class:`.MatchDetail` instance.
+
+		*patterns* (:class:`~collections.abc.Sequence` of :class:`~pathspec.pattern.Pattern`)
+		contains the patterns that matched the file in the order they were
+		encountered.
+		"""
+
+		self.patterns = patterns
+		"""
+		*patterns* (:class:`~collections.abc.Sequence` of :class:`~pathspec.pattern.Pattern`)
+		contains the patterns that matched the file in the order they were
+		encountered.
+		"""
+
+
+class TreeEntry(object):
+	"""
+	The :class:`.TreeEntry` class contains information about a file-system
+	entry.
+	"""
+
+	#: Make the class dict-less.
+	__slots__ = ('_lstat', 'name', 'path', '_stat')
+
+	def __init__(self, name, path, lstat, stat):
+		# type: (Text, Text, os.stat_result, os.stat_result) -> None
+		"""
+		Initialize the :class:`.TreeEntry` instance.
+
+		*name* (:class:`str`) is the base name of the entry.
+
+		*path* (:class:`str`) is the relative path of the entry.
+
+		*lstat* (:class:`~os.stat_result`) is the stat result of the direct
+		entry.
+
+		*stat* (:class:`~os.stat_result`) is the stat result of the entry,
+		potentially linked.
+		"""
+
+		self._lstat = lstat
+		"""
+		*_lstat* (:class:`~os.stat_result`) is the stat result of the direct
+		entry.
+		"""
+
+		self.name = name
+		"""
+		*name* (:class:`str`) is the base name of the entry.
+		"""
+
+		self.path = path
+		"""
+		*path* (:class:`str`) is the path of the entry.
+		"""
+
+		self._stat = stat
+		"""
+		*_stat* (:class:`~os.stat_result`) is the stat result of the linked
+		entry.
+		"""
+
+	def is_dir(self, follow_links=None):
+		# type: (Optional[bool]) -> bool
+		"""
+		Get whether the entry is a directory.
+
+		*follow_links* (:class:`bool` or :data:`None`) is whether to follow
+		symbolic links. If this is :data:`True`, a symlink to a directory
+		will result in :data:`True`. Default is :data:`None` for :data:`True`.
+
+		Returns whether the entry is a directory (:class:`bool`).
+		"""
+		if follow_links is None:
+			follow_links = True
+
+		node_stat = self._stat if follow_links else self._lstat
+		return stat.S_ISDIR(node_stat.st_mode)
+
+	def is_file(self, follow_links=None):
+		# type: (Optional[bool]) -> bool
+		"""
+		Get whether the entry is a regular file.
+
+		*follow_links* (:class:`bool` or :data:`None`) is whether to follow
+		symbolic links. If this is :data:`True`, a symlink to a regular file
+		will result in :data:`True`. Default is :data:`None` for :data:`True`.
+
+		Returns whether the entry is a regular file (:class:`bool`).
+		"""
+		if follow_links is None:
+			follow_links = True
+
+		node_stat = self._stat if follow_links else self._lstat
+		return stat.S_ISREG(node_stat.st_mode)
+
+	def is_symlink(self):
+		# type: () -> bool
+		"""
+		Returns whether the entry is a symbolic link (:class:`bool`).
+		"""
+		return stat.S_ISLNK(self._lstat.st_mode)
+
+	def stat(self, follow_links=None):
+		# type: (Optional[bool]) -> os.stat_result
+		"""
+		Get the cached stat result for the entry.
+
+		*follow_links* (:class:`bool` or :data:`None`) is whether to follow
+		symbolic links. If this is :data:`True`, the stat result of the
+		linked file will be returned. Default is :data:`None` for :data:`True`.
+
+		Returns that stat result (:class:`~os.stat_result`).
+		"""
+		if follow_links is None:
+			follow_links = True
+
+		return self._stat if follow_links else self._lstat