1 files changed, 146 insertions, 0 deletions
diff --git a/catapult/common/py_vulcanize/py_vulcanize/fake_fs.py b/catapult/common/py_vulcanize/py_vulcanize/fake_fs.py
new file mode 100644
index 00000000..dfcb5e60
--- /dev/null
+++ b/catapult/common/py_vulcanize/py_vulcanize/fake_fs.py
@@ -0,0 +1,146 @@
+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import codecs
+import os
+import sys
+import collections
+import StringIO
+
+
+class WithableStringIO(StringIO.StringIO):
+
+  def __enter__(self, *args):
+    return self
+
+  def __exit__(self, *args):
+    pass
+
+
+class FakeFS(object):
+
+  def __init__(self, initial_filenames_and_contents=None):
+    self._file_contents = {}
+    if initial_filenames_and_contents:
+      for k, v in initial_filenames_and_contents.iteritems():
+        self._file_contents[k] = v
+
+    self._bound = False
+    self._real_codecs_open = codecs.open
+    self._real_open = sys.modules['__builtin__'].open
+    self._real_abspath = os.path.abspath
+    self._real_exists = os.path.exists
+    self._real_walk = os.walk
+    self._real_listdir = os.listdir
+
+  def __enter__(self):
+    self.Bind()
+    return self
+
+  def __exit__(self, *args):
+    self.Unbind()
+
+  def Bind(self):
+    assert not self._bound
+    codecs.open = self._FakeCodecsOpen
+    sys.modules['__builtin__'].open = self._FakeOpen
+    os.path.abspath = self._FakeAbspath
+    os.path.exists = self._FakeExists
+    os.walk = self._FakeWalk
+    os.listdir = self._FakeListDir
+    self._bound = True
+
+  def Unbind(self):
+    assert self._bound
+    codecs.open = self._real_codecs_open
+    sys.modules['__builtin__'].open = self._real_open
+    os.path.abspath = self._real_abspath
+    os.path.exists = self._real_exists
+    os.walk = self._real_walk
+    os.listdir = self._real_listdir
+    self._bound = False
+
+  def AddFile(self, path, contents):
+    assert path not in self._file_contents
+    path = os.path.normpath(path)
+    self._file_contents[path] = contents
+
+  def _FakeOpen(self, path, mode=None):
+    if mode is None:
+      mode = 'r'
+    if mode == 'r' or mode == 'rU' or mode == 'rb':
+      if path not in self._file_contents:
+        return self._real_open(path, mode)
+      return WithableStringIO(self._file_contents[path])
+
+    raise NotImplementedError()
+
+  def _FakeCodecsOpen(self, path, mode=None,
+                      encoding=None):  # pylint: disable=unused-argument
+    if mode is None:
+      mode = 'r'
+    if mode == 'r' or mode == 'rU' or mode == 'rb':
+      if path not in self._file_contents:
+        return self._real_open(path, mode)
+      return WithableStringIO(self._file_contents[path])
+
+    raise NotImplementedError()
+
+  def _FakeAbspath(self, path):
+    """Normalize the path and ensure it starts with os.path.sep.
+
+    The tests all assume paths start with things like '/my/project',
+    and this abspath implementaion makes that assumption work correctly
+    on Windows.
+    """
+    normpath = os.path.normpath(path)
+    if not normpath.startswith(os.path.sep):
+      normpath = os.path.sep + normpath
+    return normpath
+
+  def _FakeExists(self, path):
+    if path in self._file_contents:
+      return True
+    return self._real_exists(path)
+
+  def _FakeWalk(self, top):
+    assert os.path.isabs(top)
+    all_filenames = self._file_contents.keys()
+    pending_prefixes = collections.deque()
+    pending_prefixes.append(top)
+    visited_prefixes = set()
+    while len(pending_prefixes):
+      prefix = pending_prefixes.popleft()
+      if prefix in visited_prefixes:
+        continue
+      visited_prefixes.add(prefix)
+      if prefix.endswith(os.path.sep):
+        prefix_with_trailing_sep = prefix
+      else:
+        prefix_with_trailing_sep = prefix + os.path.sep
+
+      dirs = set()
+      files = []
+      for filename in all_filenames:
+        if not filename.startswith(prefix_with_trailing_sep):
+          continue
+        relative_to_prefix = os.path.relpath(filename, prefix)
+
+        dirpart = os.path.dirname(relative_to_prefix)
+        if len(dirpart) == 0:
+          files.append(relative_to_prefix)
+          continue
+        parts = dirpart.split(os.sep)
+        if len(parts) == 0:
+          dirs.add(dirpart)
+        else:
+          pending = os.path.join(prefix, parts[0])
+          dirs.add(parts[0])
+          pending_prefixes.appendleft(pending)
+
+      dirs = sorted(dirs)
+      yield prefix, dirs, files
+
+  def _FakeListDir(self, dirname):
+    raise NotImplementedError()