[Findit] Initial code of findit for crash. Add scorers to apply heuristic rules.

appengine/findit/crash/crash_util.py

Index: appengine/findit/crash/crash_util.py
diff --git a/appengine/findit/crash/crash_util.py b/appengine/findit/crash/crash_util.py
new file mode 100644
index 0000000000000000000000000000000000000000..9d1bd2b41a144fb62d9a5582310935490a525747
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+++ b/appengine/findit/crash/crash_util.py
@@ -0,0 +1,45 @@
+# 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 defaultdict
+
+
+def IsSameFilePath(path_1, path_2):
+  """Determines 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:
+    path_1 (str): First path.
+    path_2 (str): Second path to compare.
+
+  Returns:
+    Boolean, True if it they are thought to be a same path, False otherwise.
+  """
+  # TODO(katesonia): Think of better way to determine whether 2 paths are the
+  # same or not.
+  path_parts_1 = path_1.lower().split('/')
+  path_parts_2 = path_2.lower().split('/')
+
+  if path_parts_1[-1] != path_parts_2[-1]:
+    return False
+
+  def _GetPathPartsCount(path_parts):
+    path_parts_count = defaultdict(int)
+
+    for path_part in path_parts:
+      path_parts_count[path_part] += 1
+
+    return path_parts_count
+
+  parts_count_1 = _GetPathPartsCount(path_parts_1)
+  parts_count_2 = _GetPathPartsCount(path_parts_2)
+
+  # Get number of same path parts between path_1 and path_2. For example:
+  # a/b/b/b/f.cc and a/b/b/c/d/f.cc have 4 path parts the same in total.
+  total_same_parts = sum([min(parts_count_1[part], parts_count_2[part]) for
+                          part in parts_count_1 if part in path_parts_2])
+
+  return total_same_parts >= (min(3, min(len(path_parts_1), len(path_parts_2))))