[Telemetry] Move discover to common/py_utils

telemetry/telemetry/core/discover.py

-# Copyright 2012 The Chromium Authors. All rights reserved.
+# Copyright 2017 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 fnmatch
-import inspect
-import os
-import re
-import sys
+"""Shim for discover; will be removed once #3612 is fixed."""
 
-from py_utils import camel_case
+from py_utils import discover
 
-
-def DiscoverModules(start_dir, top_level_dir, pattern='*'):
-  """Discover all modules in |start_dir| which match |pattern|.
-
-  Args:
-    start_dir: The directory to recursively search.
-    top_level_dir: The top level of the package, for importing.
-    pattern: Unix shell-style pattern for filtering the filenames to import.
-
-  Returns:
-    list of modules.
-  """
-  # start_dir and top_level_dir must be consistent with each other.
-  start_dir = os.path.realpath(start_dir)
-  top_level_dir = os.path.realpath(top_level_dir)
-
-  modules = []
-  sub_paths = list(os.walk(start_dir))
-  # We sort the directories & file paths to ensure a deterministic ordering when
-  # traversing |top_level_dir|.
-  sub_paths.sort(key=lambda paths_tuple: paths_tuple[0])
-  for dir_path, _, filenames in sub_paths:
-    # Sort the directories to walk recursively by the directory path.
-    filenames.sort()
-    for filename in filenames:
-      # Filter out unwanted filenames.
-      if filename.startswith('.') or filename.startswith('_'):
-        continue
-      if os.path.splitext(filename)[1] != '.py':
-        continue
-      if not fnmatch.fnmatch(filename, pattern):
-        continue
-
-      # Find the module.
-      module_rel_path = os.path.relpath(
-          os.path.join(dir_path, filename), top_level_dir)
-      module_name = re.sub(r'[/\\]', '.', os.path.splitext(module_rel_path)[0])
-
-      # Import the module.
-      try:
-        # Make sure that top_level_dir is the first path in the sys.path in case
-        # there are naming conflict in module parts.
-        original_sys_path = sys.path[:]
-        sys.path.insert(0, top_level_dir)
-        module = __import__(module_name, fromlist=[True])
-        modules.append(module)
-      finally:
-        sys.path = original_sys_path
-  return modules
-
-
-def AssertNoKeyConflicts(classes_by_key_1, classes_by_key_2):
-  for k in classes_by_key_1:
-    if k in classes_by_key_2:
-      assert classes_by_key_1[k] is classes_by_key_2[k], (
-          'Found conflicting classes for the same key: '
-          'key=%s, class_1=%s, class_2=%s' % (
-              k, classes_by_key_1[k], classes_by_key_2[k]))
-
-
-# TODO(dtu): Normalize all discoverable classes to have corresponding module
-# and class names, then always index by class name.
-def DiscoverClasses(start_dir,
-                    top_level_dir,
-                    base_class,
-                    pattern='*',
-                    index_by_class_name=True,
-                    directly_constructable=False):
-  """Discover all classes in |start_dir| which subclass |base_class|.
-
-  Base classes that contain subclasses are ignored by default.
-
-  Args:
-    start_dir: The directory to recursively search.
-    top_level_dir: The top level of the package, for importing.
-    base_class: The base class to search for.
-    pattern: Unix shell-style pattern for filtering the filenames to import.
-    index_by_class_name: If True, use class name converted to
-        lowercase_with_underscores instead of module name in return dict keys.
-    directly_constructable: If True, will only return classes that can be
-        constructed without arguments
-
-  Returns:
-    dict of {module_name: class} or {underscored_class_name: class}
-  """
-  modules = DiscoverModules(start_dir, top_level_dir, pattern)
-  classes = {}
-  for module in modules:
-    new_classes = DiscoverClassesInModule(
-        module, base_class, index_by_class_name, directly_constructable)
-    # TODO(nednguyen): we should remove index_by_class_name once
-    # benchmark_smoke_unittest in chromium/src/tools/perf no longer relied
-    # naming collisions to reduce the number of smoked benchmark tests.
-    # crbug.com/548652
-    if index_by_class_name:
-      AssertNoKeyConflicts(classes, new_classes)
-    classes = dict(classes.items() + new_classes.items())
-  return classes
-
-
-# TODO(nednguyen): we should remove index_by_class_name once
-# benchmark_smoke_unittest in chromium/src/tools/perf no longer relied
-# naming collisions to reduce the number of smoked benchmark tests.
-# crbug.com/548652
-def DiscoverClassesInModule(module,
-                            base_class,
-                            index_by_class_name=False,
-                            directly_constructable=False):
-  """Discover all classes in |module| which subclass |base_class|.
-
-  Base classes that contain subclasses are ignored by default.
-
-  Args:
-    module: The module to search.
-    base_class: The base class to search for.
-    index_by_class_name: If True, use class name converted to
-        lowercase_with_underscores instead of module name in return dict keys.
-
-  Returns:
-    dict of {module_name: class} or {underscored_class_name: class}
-  """
-  classes = {}
-  for _, obj in inspect.getmembers(module):
-    # Ensure object is a class.
-    if not inspect.isclass(obj):
-      continue
-    # Include only subclasses of base_class.
-    if not issubclass(obj, base_class):
-      continue
-    # Exclude the base_class itself.
-    if obj is base_class:
-      continue
-    # Exclude protected or private classes.
-    if obj.__name__.startswith('_'):
-      continue
-    # Include only the module in which the class is defined.
-    # If a class is imported by another module, exclude those duplicates.
-    if obj.__module__ != module.__name__:
-      continue
-
-    if index_by_class_name:
-      key_name = camel_case.ToUnderscore(obj.__name__)
-    else:
-      key_name = module.__name__.split('.')[-1]
-    if not directly_constructable or IsDirectlyConstructable(obj):
-      if key_name in classes and index_by_class_name:
-        assert classes[key_name] is obj, (
-          'Duplicate key_name with different objs detected: '
-          'key=%s, obj1=%s, obj2=%s' % (key_name, classes[key_name], obj))
-      else:
-        classes[key_name] = obj
-
-  return classes
-
-
-def IsDirectlyConstructable(cls):
-  """Returns True if instance of |cls| can be construct without arguments."""
-  assert inspect.isclass(cls)
-  if not hasattr(cls, '__init__'):
-    # Case |class A: pass|.
-    return True
-  if cls.__init__ is object.__init__:
-    # Case |class A(object): pass|.
-    return True
-  # Case |class (object):| with |__init__| other than |object.__init__|.
-  args, _, _, defaults = inspect.getargspec(cls.__init__)
-  if defaults is None:
-    defaults = ()
-  # Return true if |self| is only arg without a default.
-  return len(args) == len(defaults) + 1
-
-
-_counter = [0]
-
-
-def _GetUniqueModuleName():
-  _counter[0] += 1
-  return "module_" + str(_counter[0])
+DiscoverClasses = discover.DiscoverClasses
+DiscoverClassesInModule = discover.DiscoverClassesInModule