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

tools/findit/crash_utils.py

Index: tools/findit/crash_utils.py
diff --git a/tools/findit/crash_utils.py b/tools/findit/crash_utils.py
new file mode 100644
index 0000000000000000000000000000000000000000..b663249045fdaec7c5f1acdd82b84568bd164fa4
--- /dev/null
+++ b/tools/findit/crash_utils.py
@@ -0,0 +1,286 @@
+# 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 cgi
+import json
+import os
+import time
+import urllib
+

[stgao, 2014/08/07 21:03:37]

One more empty line above.

[jeun, 2014/08/07 22:03:20]

Done.

+INFINITY = float('inf')
+
+
+def NormalizePathLinux(path):
+  """Normalizes linux path.
+
+  Args:
+    path: A string representing a path.
+
+  Returns:
+    A tuple containing a component this path is in (e.g blink, skia, etc)
+    and a path in that component's repository.
+  """
+  normalized_path = os.path.abspath(path)
+
+  if 'src/v8/' in normalized_path:
+    component = 'v8'
+    normalized_path = normalized_path.split('src/v8/')[1]
+
+  # TODO(jeun): Integrate with parsing DEPS file.
+  if 'WebKit/' in normalized_path:
+    component = 'blink'
+    normalized_path = ''.join(path.split('WebKit/')[1:])
+  else:
+    component = 'chromium'
+
+  if '/build/' in normalized_path:
+    normalized_path = normalized_path.split('/build/')[-1]
+
+  if not (normalized_path.startswith('src/') or
+      normalized_path.startswith('Source/')):
+    normalized_path = 'src/' + normalized_path
+
+  return (component, normalized_path)
+
+
+def SplitRange(regression):
+  """Splits a range as retrieved from clusterfuzz.
+
+  Args:
+    regression: A string in format 'r1234:r5678'.
+
+  Returns:
+    A list containing two numbers represented in string, for example
+    ['1234','5678'].
+  """
+  revisions = regression.split(':')
+
+  # If regression information is not available, return none.
+  if len(revisions) != 2:
+    return None
+
+  # Strip 'r' from both start and end range.
+  start_range = revisions[0].lstrip('r')
+  end_range = revisions[1].lstrip('r')
+
+  return [start_range, end_range]
+
+
+def LoadJSON(json_string):
+  """Loads json object from string, or None.
+
+  Args:
+    json_string: A string to get object from.
+
+  Returns:
+    JSON object if the string represents a JSON object, None otherwise.
+  """
+  try:
+    data = json.loads(json_string)
+  except ValueError:
+    data = None
+
+  return data
+
+
+def GetDataFromURL(url, retries=10, sleep_time=0.1):
+  """Retrieves raw data from URL, tries 10 times.
+
+  Args:
+    url: URL to get data from.
+    retries: Number of times to retry connection.
+    sleep_time: Time in seconds to wait before retrying connection.
+
+  Returns:
+    None if the data retrieval fails, or the raw data.
+  """
+  data = None
+  for i in range(retries):
+    # Retrieves data from URL.
+    try:
+      data = urllib.urlopen(url)
+
+      # If retrieval is successful, return the data.
+      if data:
+        return data.read()
+
+    # If retrieval fails, try after sleep_time second.
+    except IOError:
+      time.sleep(sleep_time)
+      continue
+
+  # Return None if it fails to read data from URL 'retries' times.
+  return None
+
+
+def FindMinLineDistance(crashed_line_list, changed_line_numbers):
+  """Calculates how far the changed line is from one of the crashes.
+
+  Finds the minimum distance between the lines that the file crashed on
+  and the lines that the file changed. For example, if the file crashed on
+  line 200 and the CL changes line 203,204 and 205, the function returns 3.
+
+  Args:
+    crashed_line_list: A list of lines that the file crashed on.
+    changed_line_numbers: A list of lines that the file changed.
+
+  Returns:
+    The minimum distance. If either of the input lists is empty,
+    it returns inf.
+
+  """
+  min_distance = INFINITY
+
+  for line in crashed_line_list:
+    for distance in changed_line_numbers:
+      # Find the current distance and update the min if current distance is
+      # less than current min.
+      current_distance = abs(line - distance)
+      if current_distance < min_distance:
+        min_distance = current_distance
+
+  return min_distance
+
+
+def GuessIfSameSubPath(path1, path2):
+  """Guesses if two paths represent same path.
+
+  Compares the name of the folders in the path (by split('/')), and checks
+  if they match either more than 3 or min of path lengths.
+
+  Args:
+    path1: First path.
+    path2: Second path to compare.
+
+  Returns:
+    True if it they are thought to be a same path, False otherwise.
+  """
+  path1 = path1.split('/')
+  path2 = path2.split('/')
+
+  intersection = set(path1).intersection(set(path2))
+  return len(intersection) >= (min(3, min(len(path1), len(path2))))
+
+
+def FindMinStackFrameNumber(stack_frame_indices, priorities):
+  """Finds the minimum stack number, from the list of stack numbers.
+
+  Args:
+    stack_frame_indices: A list of lists containing stack position.
+    priorities: A list of of priority for each file.
+
+  Returns:
+    Inf if stack_frame_indices is empty, minimum stack number otherwise.
+  """
+  # Get the indexes of the highest priority (or low priority number).
+  highest_priority = min(priorities)
+  highest_priority_indices = []
+  for i in range(len(priorities)):
+    if priorities[i] == highest_priority:
+      highest_priority_indices.append(i)
+
+  # Gather the list of stack frame numbers for the files that change the
+  # crash lines.
+  flattened = []
+  for i in highest_priority_indices:
+    flattened += stack_frame_indices[i]
+
+  # If no stack frame information is available, return inf. Else, return min.
+  if not flattened:
+    return INFINITY
+  else:
+    return min(flattened)
+
+
+def AddHyperlink(text, link):
+  """Returns a string with HTML link tag.
+
+  Args:
+    text: A string to add link.
+    link: A link to add to the string.
+
+  Returns:
+    A string with hyperlink added.
+  """
+  sanitized_link = cgi.escape(link, quote=True)
+  sanitized_text = cgi.escape(text)
+  return '<a href="%s">%s</a>' % (sanitized_link, sanitized_text)
+
+
+def PrettifyList(l):
+  """Returns a string representation of a list.
+
+  It adds comma in between the elements and removes the brackets.
+  Args:
+    l: A list to prettify.
+  Returns:
+    A string representation of the list.
+  """
+  return str(l)[1:-1]
+
+
+def PrettifyFiles(file_list):
+  """Returns a string representation of a list of file names.
+
+  Args:
+    file_list: A list of tuple, (file_name, file_url).
+  Returns:
+    A string representation of file names with their urls.
+  """
+  ret = ['\n']
+  for file_name, file_url in file_list:
+    ret.append('      %s\n' % AddHyperlink(file_name, file_url))
+  return ''.join(ret)
+
+
+def Intersection(crashed_line_list, stack_frame_index, changed_line_numbers,
+                 line_range=3):
+  """Finds the overlap betwee changed lines and crashed lines.
+
+  Finds the intersection of the lines that caused the crash and
+  lines that the file changes. The intersection looks within 3 lines
+  of the line that caused the crash.
+
+  Args:
+    crashed_line_list: A list of lines that the file crashed on.
+    stack_frame_index: A list of positions in stack for each of the lines.
+    changed_line_numbers: A list of lines that the file changed.
+    line_range: Number of lines to look backwards from crashed lines.
+
+  Returns:
+    line_intersection: Intersection between crashed_line_list and
+                       changed_line_numbers.
+    stack_frame_index_intersection: Stack number for each of the intersections.
+  """
+  line_intersection = []
+  stack_frame_index_intersection = []
+
+  # Iterate through the crashed lines, and its occurence in stack.
+  for (line, stack_frame_index) in zip(crashed_line_list, stack_frame_index):
+

[stgao, 2014/08/07 21:03:37]

It seems the code has empty lines after for. Would you please remove all of them
after for?

[jeun, 2014/08/07 22:03:20]

Done.

+    # Also check previous 3 lines.

[stgao, 2014/08/07 21:03:37]

Comment needs updating, as 3 is invalid now.

[jeun, 2014/08/07 22:03:20]

Done.

+    line_minus_n = range(line - line_range, line + 1)
+
+    for changed_line in changed_line_numbers:
+
+      # If a CL does not change crahsed line, check next line.
+      if changed_line not in line_minus_n:
+        continue
+
+      # If the changed line is exactly the crashed line, add that line.
+      if line in changed_line_numbers:
+        intersected_line = line
+
+      # If the changed line is in 3 lines of the crashed line, add the line.
+      else:
+        intersected_line = changed_line
+
+      # Avoid adding the same line twice.
+      if intersected_line not in line_intersection:
+        line_intersection.append(intersected_line)
+        stack_frame_index_intersection.append(stack_frame_index)
+
+      break
+
+  return (line_intersection, stack_frame_index_intersection)