def Canonicalize(self, path):
'''Returns the canonical path for |path|.
'''
canonical_paths, simplified_paths_map = self._LoadCache().Get()
# Path may already be the canonical path.
if path in canonical_paths:
return path
# Path not found. Our single heuristic: find |base| in the directory
# structure with the longest common prefix of |path|.
_, base = SplitParent(path)
potential_paths = simplified_paths_map.get(_SimplifyFileName(base))
if not potential_paths:
# There is no file with anything close to that name.
return path
# The most likely canonical file is the one with the longest common prefix
# with |path|. This is slightly weaker than it could be; |path| is
# compared, not the simplified form of |path|, which may matter.
max_prefix = potential_paths[0]
max_prefix_length = len(posixpath.commonprefix((max_prefix, path)))
for path_for_file in potential_paths[1:]:
prefix_length = len(posixpath.commonprefix((path_for_file, path)))
if prefix_length > max_prefix_length:
max_prefix, max_prefix_length = path_for_file, prefix_length
return max_prefix
def Exists(self, path):
'''Returns a Future to the existence of |path|; True if |path| exists,
False if not. This method will not throw a FileNotFoundError unlike
the Read* methods, however it may still throw a FileSystemError.
There are several ways to implement this method via the interface but this
method exists to do so in a canonical and most efficient way for caching.
'''
AssertIsValid(path)
if path == '':
# There is always a root directory.
return Future(value=True)
parent, base = SplitParent(path)
def handle(error):
if isinstance(error, FileNotFoundError):
return False
raise error
return self.ReadSingle(ToDirectory(parent)).Then(
lambda l: base in l, handle)
def Exists(self, path):
'''Returns a Future to the existence of |path|; True if |path| exists,
False if not. This method will not throw a FileNotFoundError unlike
the Read* methods, however it may still throw a FileSystemError.
There are several ways to implement this method via the interface but this
method exists to do so in a canonical and most efficient way for caching.
'''
AssertIsValid(path)
if path == '':
# There is always a root directory.
return Future(value=True)
parent, base = SplitParent(path)
list_future = self.ReadSingle(ToDirectory(parent))
def resolve():
try:
return base in list_future.Get()
except FileNotFoundError:
return False
return Future(callback=resolve)
def Canonicalize(self, path):
'''Returns the canonical path for |path|.
'''
canonical_paths, simplified_paths_map = self._LoadCache().Get()
# Path may already be the canonical path.
if path in canonical_paths:
return path
# Path not found. Our single heuristic: find |base| in the directory
# structure with the longest common prefix of |path|.
_, base = SplitParent(path)
# Paths with a non-extension dot separator lose information in
# _SimplifyFileName, so we try paths both with and without the dot to
# maximize the possibility of finding the right path.
potential_paths = (
simplified_paths_map.get(_Normalize(base), []) +
simplified_paths_map.get(_Normalize(base, splittext=True), []))
if potential_paths == []:
# There is no file with anything close to that name.
return path
# The most likely canonical file is the one with the longest common prefix
# with |path|. This is slightly weaker than it could be; |path| is
# compared without symbols, not the simplified form of |path|,
# which may matter.
max_prefix = potential_paths[0]
max_prefix_length = len(_CommonNormalizedPrefix(max_prefix, path))
for path_for_file in potential_paths[1:]:
prefix_length = len(_CommonNormalizedPrefix(path_for_file, path))
if prefix_length > max_prefix_length:
max_prefix, max_prefix_length = path_for_file, prefix_length
return max_prefix
def testSplitParent(self):
self.assertEqual(('', 'hi'), SplitParent('hi'))
self.assertEqual(('', 'hi/'), SplitParent('hi/'))
self.assertEqual(('/', 'hi'), SplitParent('/hi'))
self.assertEqual(('/', 'hi/'), SplitParent('/hi/'))
self.assertEqual(('parent', 'hi'), SplitParent('parent/hi'))
self.assertEqual(('parent', 'hi/'), SplitParent('parent/hi/'))
self.assertEqual(('/parent', 'hi'), SplitParent('/parent/hi'))
self.assertEqual(('/parent', 'hi/'), SplitParent('/parent/hi/'))
self.assertEqual(('p1/p2', 'hi'), SplitParent('p1/p2/hi'))
self.assertEqual(('p1/p2', 'hi/'), SplitParent('p1/p2/hi/'))
self.assertEqual(('/p1/p2', 'hi'), SplitParent('/p1/p2/hi'))
self.assertEqual(('/p1/p2', 'hi/'), SplitParent('/p1/p2/hi/'))