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Lib/site-packages/pipenv/patched/piptools/cache.py

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+# coding: utf-8
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import json
+import os
+import platform
+import sys
+
+from pipenv.vendor.packaging.requirements import Requirement
+
+from .exceptions import PipToolsError
+from .utils import as_tuple, key_from_req, lookup_table
+
+_PEP425_PY_TAGS = {"cpython": "cp", "pypy": "pp", "ironpython": "ip", "jython": "jy"}
+
+
+def _implementation_name():
+    """similar to PEP 425, however the minor version is separated from the
+    major to differentation "3.10" and "31.0".
+    """
+    implementation_name = platform.python_implementation().lower()
+    implementation = _PEP425_PY_TAGS.get(implementation_name, "??")
+    return "{}{}.{}".format(implementation, *sys.version_info)
+
+
+class CorruptCacheError(PipToolsError):
+    def __init__(self, path):
+        self.path = path
+
+    def __str__(self):
+        lines = [
+            "The dependency cache seems to have been corrupted.",
+            "Inspect, or delete, the following file:",
+            "  {}".format(self.path),
+        ]
+        return os.linesep.join(lines)
+
+
+def read_cache_file(cache_file_path):
+    with open(cache_file_path, "r") as cache_file:
+        try:
+            doc = json.load(cache_file)
+        except ValueError:
+            raise CorruptCacheError(cache_file_path)
+
+        # Check version and load the contents
+        if doc["__format__"] != 1:
+            raise AssertionError("Unknown cache file format")
+        return doc["dependencies"]
+
+
+class DependencyCache(object):
+    """
+    Creates a new persistent dependency cache for the current Python version.
+    The cache file is written to the appropriate user cache dir for the
+    current platform, i.e.
+
+        ~/.cache/pip-tools/depcache-pyX.Y.json
+
+    Where py indicates the Python implementation.
+    Where X.Y indicates the Python version.
+    """
+
+    def __init__(self, cache_dir):
+        if not os.path.isdir(cache_dir):
+            os.makedirs(cache_dir)
+        cache_filename = "depcache-{}.json".format(_implementation_name())
+
+        self._cache_file = os.path.join(cache_dir, cache_filename)
+        self._cache = None
+
+    @property
+    def cache(self):
+        """
+        The dictionary that is the actual in-memory cache.  This property
+        lazily loads the cache from disk.
+        """
+        if self._cache is None:
+            self.read_cache()
+        return self._cache
+
+    def as_cache_key(self, ireq):
+        """
+        Given a requirement, return its cache key. This behavior is a little weird
+        in order to allow backwards compatibility with cache files. For a requirement
+        without extras, this will return, for example:
+
+        ("ipython", "2.1.0")
+
+        For a requirement with extras, the extras will be comma-separated and appended
+        to the version, inside brackets, like so:
+
+        ("ipython", "2.1.0[nbconvert,notebook]")
+        """
+        name, version, extras = as_tuple(ireq)
+        if not extras:
+            extras_string = ""
+        else:
+            extras_string = "[{}]".format(",".join(extras))
+        return name, "{}{}".format(version, extras_string)
+
+    def read_cache(self):
+        """Reads the cached contents into memory."""
+        if os.path.exists(self._cache_file):
+            self._cache = read_cache_file(self._cache_file)
+        else:
+            self._cache = {}
+
+    def write_cache(self):
+        """Writes the cache to disk as JSON."""
+        doc = {"__format__": 1, "dependencies": self._cache}
+        with open(self._cache_file, "w") as f:
+            json.dump(doc, f, sort_keys=True)
+
+    def clear(self):
+        self._cache = {}
+        self.write_cache()
+
+    def __contains__(self, ireq):
+        pkgname, pkgversion_and_extras = self.as_cache_key(ireq)
+        return pkgversion_and_extras in self.cache.get(pkgname, {})
+
+    def __getitem__(self, ireq):
+        pkgname, pkgversion_and_extras = self.as_cache_key(ireq)
+        return self.cache[pkgname][pkgversion_and_extras]
+
+    def __setitem__(self, ireq, values):
+        pkgname, pkgversion_and_extras = self.as_cache_key(ireq)
+        self.cache.setdefault(pkgname, {})
+        self.cache[pkgname][pkgversion_and_extras] = values
+        self.write_cache()
+
+    def reverse_dependencies(self, ireqs):
+        """
+        Returns a lookup table of reverse dependencies for all the given ireqs.
+
+        Since this is all static, it only works if the dependency cache
+        contains the complete data, otherwise you end up with a partial view.
+        This is typically no problem if you use this function after the entire
+        dependency tree is resolved.
+        """
+        ireqs_as_cache_values = [self.as_cache_key(ireq) for ireq in ireqs]
+        return self._reverse_dependencies(ireqs_as_cache_values)
+
+    def _reverse_dependencies(self, cache_keys):
+        """
+        Returns a lookup table of reverse dependencies for all the given cache keys.
+
+        Example input:
+
+            [('pep8', '1.5.7'),
+             ('flake8', '2.4.0'),
+             ('mccabe', '0.3'),
+             ('pyflakes', '0.8.1')]
+
+        Example output:
+
+            {'pep8': ['flake8'],
+             'flake8': [],
+             'mccabe': ['flake8'],
+             'pyflakes': ['flake8']}
+
+        """
+        # First, collect all the dependencies into a sequence of (parent, child)
+        # tuples, like [('flake8', 'pep8'), ('flake8', 'mccabe'), ...]
+        return lookup_table(
+            (key_from_req(Requirement(dep_name)), name)
+            for name, version_and_extras in cache_keys
+            for dep_name in self.cache[name][version_and_extras]
+        )