[Predator] Add ``Project`` class and ``ClassifySuspect`` method to project and component classifier

appengine/findit/crash/project.py

Index: appengine/findit/crash/project.py
diff --git a/appengine/findit/crash/project.py b/appengine/findit/crash/project.py
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+++ b/appengine/findit/crash/project.py
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+# 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.
+
+from collections import namedtuple
+import os
+import re
+
+from libs.gitiles.diff import ChangeType
+
+# Some projects like "chromium", have many sub projects like
+# "chromium-blink", "chromium-skia", "chromium-pdfium"...etc., for those
+# dep projects, the "chromium" ``Project`` can derive the names from their
+# dep paths.
+# Some other projects like "android_os", "clank", they don't have any dependency
+# projects that are relavent to Predator.
+_PROJECTS_WITH_DEP_PROJECTS = ['chromium']
+
+
+# TODO(http://crbug.com/659346): write the coverage tests.
+class Project(namedtuple('Project',
+    ['name', 'path_regexes', 'function_regexes',
+     'host_directories'])):
+  """A representation of a "project", which may host many sub projects.
+
+  For example: 'android_os', 'clank' or 'chromium'. Notably, a project knows
+  how to identify itself. Hence, given a stack frame, file path or dependency
+  path or whatever, we ask the ``Project``  whether it matches that frame,
+  CL, etc.
+
+  Properties:
+    name (str): The name of the project, like "chromium", "android_os".
+    path_regexes (list of re.RegexObject): Patterns of paths that project has.
+    function_regexes (list of re.RegexObject): Patterns of functions that
+      project has.
+    host_directories (list of str): The root directories of this project and
+      sub projects this project hosts.
+      N.B. If ``host_directories`` is available, this project can match
+      it with the passed-in ``dep_path`` to tell whether a suspect or stack is
+      from this project. If this information is missing, the project cannot
+      tell that from ``dep_path``; However, that doesn't mean the suspect or
+      stack does not belong to this project, we can use other information like
+      ``path_regexes`` or ``function_regexes`` to analyze.
+  """
+  __slots__ = ()
+
+  def __new__(cls, name, path_regexes=None,
+              function_regexes=None, host_directories=None):
+    path_regexes = map(re.compile, path_regexes or [])
+    function_regexes = map(re.compile, function_regexes or [])
+    host_directories = host_directories or []
+
+    return super(cls, Project).__new__(
+        cls, name, path_regexes, function_regexes, host_directories)
+
+  def MatchesStackFrame(self, frame):
+    """Returns true if this project matches the frame."""
+    # Sometimes some marker information are in the frame.raw_file_path.
+    # An example, the path_regex for android_os is --
+    # "https___googleplex-android.googlesource.com_a_platform_manifest.git/".
+    # It can only be found in frame.raw_file_path, since the frame.file_path
+    # has those kind of information stripped.
+    for path_regex in self.path_regexes:
+      if (path_regex.match(os.path.join(frame.dep_path, frame.file_path)) or
+          path_regex.match(frame.raw_file_path)):
+        return True
+
+    for function_regex in self.function_regexes:
+      if function_regex.match(frame.function):
+        return True
+
+    for host_directory in self.host_directories:
+      if frame.dep_path.startswith(host_directory):
+        return True
+
+    return False
+
+  def MatchesTouchedFile(self, dep_path, file_path):
+    """Returns true if this project matches the file path."""
+    # If the path matches the path patterns.
+    for path_regex in self.path_regexes:
+      if path_regex.match(os.path.join(dep_path, file_path)):
+        return True
+
+    # If the dep_path hosted by this project.
+    for host_directory in self.host_directories:
+      if dep_path.startswith(host_directory):
+        return True
+
+    return False
+
+  def GetName(self, dep_path=None):
+    """Returns the project name based on dep path.
+
+    N.B. (1) If this project doesn't have dep projects, just return the project
+    name. (2) If this project does, return the derived dep project name based on
+    the self.host_directories.
+    """
+    if self.name not in _PROJECTS_WITH_DEP_PROJECTS or dep_path is None:
+      return self.name
+
+    # For chromium project, get the name of the sub project from ``dep_path``.
+    for host_directory in self.host_directories:
+      if dep_path.startswith(host_directory):
+        path = dep_path[len(host_directory):]
+        if not path:
+          return self.name
+
+        return '%s-%s' % (self.name, path.split('/')[0].lower())
+
+    # Unknown path, return the whole path as project name.
+    return '%s-%s' % (self.name,
+                      '_'.join([dep_part for dep_part in dep_path.split('/')
+                                if dep_part]))