RELAND of Cross-repo recipe package system.

third_party/recipe_engine/util.py

-# Copyright 2013-2015 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 functools
-import os
-
-from cStringIO import StringIO
-
-class RecipeAbort(Exception):
-  pass
-
-
-class ModuleInjectionError(AttributeError):
-  pass
-
-
-class ModuleInjectionSite(object):
-  def __init__(self, owner_module=None):
-    self.owner_module = owner_module
-
-  def __getattr__(self, key):
-    if self.owner_module is None:
-      raise ModuleInjectionError(
-        "RecipeApi has no dependency %r. (Add it to DEPS?)" % (key,))
-    else:
-      raise ModuleInjectionError(
-        "Recipe Module %r has no dependency %r. (Add it to __init__.py:DEPS?)"
-        % (self.owner_module.name, key))
-
-
-class Placeholder(object):
-  """Base class for json placeholders. Do not use directly."""
-  def __init__(self):
-    self.name_pieces = None
-
-  @property
-  def backing_file(self):  # pragma: no cover
-    """Return path to a temp file that holds or receives the data.
-
-    Valid only after 'render' has been called.
-    """
-    raise NotImplementedError
-
-  def render(self, test):  # pragma: no cover
-    """Return [cmd items]*"""
-    raise NotImplementedError
-
-  def result(self, presentation, test):
-    """Called after step completion.
-
-    Args:
-      presentation (StepPresentation) - for the current step.
-      test (PlaceholderTestData) - test data for this placeholder.
-
-    Returns value to add to step result.
-
-    May optionally modify presentation as a side-effect.
-    """
-    pass
-
-  @property
-  def name(self):
-    assert self.name_pieces
-    return "%s.%s" % self.name_pieces
-
-
-def static_wraps(func):
-  wrapped_fn = func
-  if isinstance(func, staticmethod):
-    # __get__(obj) is the way to get the function contained in the staticmethod.
-    # python 2.7+ has a __func__ member, but previous to this the attribute
-    # doesn't exist. It doesn't matter what the obj is, as long as it's not
-    # None.
-    wrapped_fn = func.__get__(object)
-  return functools.wraps(wrapped_fn)
-
-
-def static_call(obj, func, *args, **kwargs):
-  if isinstance(func, staticmethod):
-    return func.__get__(obj)(*args, **kwargs)
-  else:
-    return func(obj, *args, **kwargs)
-
-
-def static_name(obj, func):
-  if isinstance(func, staticmethod):
-    return func.__get__(obj).__name__
-  else:
-    return func.__name__
-
-
-def returns_placeholder(func):
-  @static_wraps(func)
-  def inner(self, *args, **kwargs):
-    ret = static_call(self, func, *args, **kwargs)
-    assert isinstance(ret, Placeholder)
-    ret.name_pieces = (self.name, static_name(self, func))
-    return ret
-  # prevent this placeholder-returning function from becoming a composite_step.
-  inner._non_step = True # pylint: disable=protected-access
-  return inner
-
-
-def cached_unary(f):
-  """Decorator that caches/memoizes an unary function result.
-
-  If the function throws an exception, the cache table will not be updated.
-  """
-  cache = {}
-  empty = object()
-
-  @functools.wraps(f)
-  def cached_f(inp):
-    cache_entry = cache.get(inp, empty)
-    if cache_entry is empty:
-      cache_entry = f(inp)
-      cache[inp] = cache_entry
-    return cache_entry
-  return cached_f
-
-
-def scan_directory(path, predicate):
-  """Recursively scans a directory and yields paths that match predicate."""
-  for root, _dirs, files in os.walk(path):
-    for file_name in (f for f in files if predicate(f)):
-      file_path = os.path.join(root, file_name)
-      yield file_path
-
-
-class StringListIO(object):
-  def __init__(self):
-    self.lines = [StringIO()]
-
-  def write(self, s):
-    while s:
-      i = s.find('\n')
-      if i == -1:
-        self.lines[-1].write(s)
-        break
-      self.lines[-1].write(s[:i])
-      self.lines[-1] = self.lines[-1].getvalue()
-      self.lines.append(StringIO())
-      s = s[i+1:]
-
-  def close(self):
-    if not isinstance(self.lines[-1], basestring):
-      self.lines[-1] = self.lines[-1].getvalue()