Converting various classes to namedtuples

appengine/findit/crash/stacktrace.py

 # Copyright 2016 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 logging
 import re
 
 from crash import parse_util
 from crash.type_enums import CallStackFormatType
 from crash.type_enums import CallStackLanguageType
 
 # Used to parse a line into StackFrame of a Callstack.
 CALLSTACK_FORMAT_TO_PATTERN = {
     CallStackFormatType.JAVA: re.compile(
         r'at ([A-Za-z0-9$._<>]+)\(\w+(\.java)?:(\d+)\)'),
     CallStackFormatType.SYZYASAN: re.compile(
         r'(CF: )?(.*?)( \(FPO: .*\) )?( \(CONV: .*\) )?\[(.*) @ (\d+)\]'),
     CallStackFormatType.DEFAULT: re.compile(
         r'(.*?):(\d+)(:\d+)?$')
 }
 
 FRAME_INDEX_PATTERN = re.compile(r'\s*#(\d+)\s.*')
 
 
-class StackFrame(object):
+class StackFrame(namedtuple('StackFrame',
+    ['index', 'dep_path', 'function', 'file_path', 'raw_file_path',
+    'crashed_line_numbers', 'repo_url'])):
   """Represents a frame in a stacktrace.
 
   Attributes:
     index (int): Index shown in the stacktrace if a stackframe line looks like
       this - '#0 ...', else use the index in the callstack list.
     dep_path (str): Path of the dep this frame represents, for example,
       'src/', 'src/v8', 'src/skia'...etc.
     function (str): Function that caused the crash.
     file_path (str): Normalized path of the crashed file, with parts dep_path
       and parts before it stripped, for example, api.cc.
     raw_file_path (str): Normalized original path of the crashed file,
       for example, /b/build/slave/mac64/build/src/v8/src/heap/
       incremental-marking-job.cc.
     crashed_line_numbers (list): Line numbers of the file that caused the crash.
     repo_url (str): Repo url of this frame.
   """
-  def __init__(self, index, dep_path, function,
-               file_path, raw_file_path, crashed_line_numbers,
-               repo_url=None):
-    self.index = index
-    self.dep_path = dep_path
-    self.function = function
-    self.file_path = file_path
-    self.raw_file_path = raw_file_path
-    self.crashed_line_numbers = crashed_line_numbers
-    self.repo_url = repo_url
+  __slots__ = ()
+
+  def __new__(cls, index, dep_path, function, file_path, raw_file_path,
+              crashed_line_numbers, repo_url=None):
+    return super(cls, StackFrame).__new__(cls,
+        index, dep_path, function, file_path, raw_file_path,
+        crashed_line_numbers, repo_url)
 
   def ToString(self):
     frame_str = '#%d in %s @ %s' % (self.index, self.function, self.file_path)
     if self.crashed_line_numbers:
       frame_str += ':%d' % self.crashed_line_numbers[0]
 
     # For example, if crashed_line_numbers is [61], returns '... f.cc:61',
     # if is [61, 62], returns '... f.cc:61:1'
     if len(self.crashed_line_numbers) > 1:
       frame_str += ':%d' % (len(self.crashed_line_numbers) - 1)
@@ skipping 149 matching lines @@
           callstack[:] = callstack[index:]
           self._crash_stack = callstack
           break
 
     # If there is no signature callstack, fall back to set crash stack using
     # the first least priority callstack.
     if self._crash_stack is None:
       self._crash_stack = sorted(self, key=lambda stack: stack.priority)[0]
 
     return self._crash_stack