Merge pull request #82 from parkerhancock/attempt_1

create lazy loading lookup class to support pickling

CHANGES.rst

@@ -1,3 +1,10 @@
+v3.9.0
+======
+
+* #81: ``Path`` objects are now pickleable if they've been
+  constructed from pickleable objects. Any restored objects
+  will re-construct the zip file with the original arguments.
+
 v3.8.1
 ======
 

test_zipp.py

@@ -6,6 +6,8 @@
 import tempfile
 import shutil
 import string
+import pickle
+import itertools
 
 import jaraco.itertools
 import func_timeout
@@ -74,13 +76,12 @@ def temp_dir():
         shutil.rmtree(tmpdir)
 
 
-pass_alpharep = parameterize(
-    ['alpharep'],
-    [
-        Invoked.wrap(build_alpharep_fixture),
-        Invoked.wrap(compose(add_dirs, build_alpharep_fixture)),
-    ],
-)
+alpharep_generators = [
+    Invoked.wrap(build_alpharep_fixture),
+    Invoked.wrap(compose(add_dirs, build_alpharep_fixture)),
+]
+
+pass_alpharep = parameterize(['alpharep'], alpharep_generators)
 
 
 class TestPath(unittest.TestCase):
@@ -407,3 +408,20 @@ def test_inheritance(self, alpharep):
         cls = type('PathChild', (zipp.Path,), {})
         file = cls(alpharep).joinpath('some dir').parent
         assert isinstance(file, cls)
+
+    @parameterize(
+        ['alpharep', 'path_type', 'subpath'],
+        itertools.product(
+            alpharep_generators,
+            [str, pathlib.Path],
+            ['', 'b/'],
+        ),
+    )
+    def test_pickle(self, alpharep, path_type, subpath):
+        print(alpharep, path_type, subpath)
+        zipfile_ondisk = path_type(self.zipfile_ondisk(alpharep))
+
+        saved_1 = pickle.dumps(zipp.Path(zipfile_ondisk, at=subpath))
+        restored_1 = pickle.loads(saved_1)
+        first, *rest = restored_1.iterdir()
+        assert first.read_text().startswith('content of ')

zipp.py

@@ -62,7 +62,25 @@ def _difference(minuend, subtrahend):
     return itertools.filterfalse(set(subtrahend).__contains__, minuend)
 
 
-class CompleteDirs(zipfile.ZipFile):
+class InitializedState:
+    """
+    Mix-in to save the initialization state for pickling.
+    """
+
+    def __init__(self, *args, **kwargs):
+        self.__args = args
+        self.__kwargs = kwargs
+        super().__init__(*args, **kwargs)
+
+    def __getstate__(self):
+        return self.__args, self.__kwargs
+
+    def __setstate__(self, state):
+        args, kwargs = state
+        super().__init__(*args, **kwargs)
+
+
+class CompleteDirs(InitializedState, zipfile.ZipFile):
     """
     A ZipFile subclass that ensures that implied directories
     are always included in the namelist.