[Findit] Plain objects to represent and parse stack trace.

tools/findit/component_dictionary.py

Index: tools/findit/component_dictionary.py
diff --git a/tools/findit/component_dictionary.py b/tools/findit/component_dictionary.py
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+# Copyright (c) 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 os
+
+
+class FileDictionary(object):
+  """Maps file in a stacktrace to its crash information.
+
+  It maps file to another dictionary, which maps the file's path to crashed
+  lines, stack frame indices and crashed functions.
+  """
+
+  def __init__(self):
+    """Initializes the file dictionary."""
+    self.file_dict = {}
+
+  def AddFile(self, file_name, file_path, crashed_line_number,
+              stack_frame_index, function):
+    """Adds file and its crash information to the map.
+
+    Args:
+      file_name: The name of the crashed file.
+      file_path: The path of the crashed file.
+      crashed_line_number: The crashed line of the file.
+      stack_frame_index: The file's position in the callstack.
+      function: The name of the crashed function.
+    """
+    # Populate the dictionary if this file/path has not been added before.
+    if file_name not in self.file_dict:
+      self.file_dict[file_name] = {}
+
+    if file_path not in self.file_dict[file_name]:
+      self.file_dict[file_name][file_path] = {}
+      self.file_dict[file_name][file_path]['line_numbers'] = []
+      self.file_dict[file_name][file_path]['stack_frame_indices'] = []
+      self.file_dict[file_name][file_path]['function'] = []
+
+    # Add the crashed line, frame index and function name.
+    self.file_dict[file_name][file_path]['line_numbers'].append(
+        crashed_line_number)
+    self.file_dict[file_name][file_path]['stack_frame_indices'].append(
+        stack_frame_index)
+    self.file_dict[file_name][file_path]['function'].append(function)
+
+  def GetPathDic(self, file_name):
+    """Returns file's path and crash information."""
+    return self.file_dict[file_name]
+
+  def GetCrashedLineNumbers(self, file_path):
+    """Returns crashed line numbers given a file path."""
+    file_name = os.path.basename(file_path)
+    return self.file_dict[file_name][file_path]['line_numbers']
+
+  def GetCrashStackFrameindex(self, file_path):
+    """Returns stack frame indices given a file path."""
+    file_name = os.path.basename(file_path)
+    return self.file_dict[file_name][file_path]['stack_frame_indices']
+
+  def GetCrashFunction(self, file_path):
+    """Returns list of crashed functions given a file path."""
+    file_name = os.path.basename(file_path)
+    return self.file_dict[file_name][file_path]['function']
+
+  def __iter__(self):
+    return iter(self.file_dict)
+
+
+class ComponentDictionary(object):
+  """Represents a file dictionary.
+
+  It maps each component path to a file dictionary.
+  """
+
+  def __init__(self, callstack, components):
+    """Initializes the dictionary with given components."""
+    self.component_dict = {}
+
+    # Create file dictionary for all the components.
+    for component in components:
+      self.component_dict[component] = FileDictionary()
+
+    # Create file dict from callstack.
+    self.__CreateFileDictFromCallstack(callstack)
+
+  def GetFileDict(self, component):
+    """Returns a file dictionary for a given component."""
+    return self.component_dict.get(component)
+
+  def __GenerateFileDict(self, stack_frame_list):
+    """Generates file dictionary, given an instance of StackFrame list."""
+    # Iterate through the list of stackframe objects.
+    for stack_frame in stack_frame_list:
+      # If the component of this line is not in the list of components to
+      # look for, ignore this line.
+      component_path = stack_frame.component_path
+      if component_path not in self.component_dict:
+        continue
+
+      # Get values of the variables
+      file_name = stack_frame.file_name
+      file_path = stack_frame.file_path
+      crashed_line_number = stack_frame.crashed_line_number
+      stack_frame_index = stack_frame.index
+      function = stack_frame.function
+
+      # Add the file to this component's dictionary of files.
+      file_dict = self.component_dict[component_path]
+      file_dict.AddFile(file_name, file_path, crashed_line_number,
+                        stack_frame_index, function)
+
+  def __CreateFileDictFromCallstack(self, callstack, top_n_frames=15):
+    """Creates a file dict that maps a file to the occurrence in the stack.
+
+    Args:
+      callstack: A list containing parsed result from a single stack
+                  within a stacktrace. For example, a stacktrace from
+                  previously-allocated thread in release build stacktrace.
+      top_n_frames: The number of frames to look for.
+
+    Returns:
+      Component_dict, a dictionary with key as a file name and value as another
+      dictionary, which maps the file's path (because there can be multiple
+      files with same name but in different directory) to the list of this
+      file's place in stack, lines that this file caused a crash, and the name
+      of the function.
+    """
+
+    # Only look at first 15 frames of the stacktrace, below those are likely
+    # to be noisy. Parse the stacktrace into the component dictionary.
+    stack_list = callstack.GetTopNFrames(top_n_frames)
+    self.__GenerateFileDict(stack_list)
+
+  def __iter__(self):
+    return iter(self.component_dict)