[Findit] Filter inline function path frames

appengine/findit/crash/stacktrace.py

Index: appengine/findit/crash/stacktrace.py
diff --git a/appengine/findit/crash/stacktrace.py b/appengine/findit/crash/stacktrace.py
index e2657c199e7b5fffe59d25d44dde9f7ecba51b7f..ffdf6df76412a9deb8f0f2befcf5ebca4aa9be85 100644
--- a/appengine/findit/crash/stacktrace.py
+++ b/appengine/findit/crash/stacktrace.py
@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import logging
+import re
 
 
 class Stacktrace(list):
@@ -10,16 +11,49 @@ class Stacktrace(list):
 
   Contains a list of callstacks, because one stacktrace may have more than
   one callstacks."""
-  def __init__(self, stack_list=None):
+  def __init__(self, stack_list=None, signature=None):
     super(Stacktrace, self).__init__(stack_list or [])
 
-  def GetCrashStack(self):
+    if signature:
+      # Filter out the types of signature, for example [Out of Memory].
+      signature = re.sub('[[][^]]*[]]\s*', '', signature)
+
+    self.signature = signature
+    self._crash_stack = None
+
+  @property
+  def crash_stack(self):
     """Gets the crash stack with the highest (lowest number) priority in
     stacktrace."""
     if not self:
       logging.warning('Cannot get crash stack for empty stacktrace: %s', self)
       return None
 
-    # Return the first stack with the least priority. The smaller the number,
-    # the higher the priority beginning with 0.
-    return sorted(self, key=lambda stack: stack.priority)[0]
+    if self._crash_stack is None and self.signature:
+      # For clusterfuzz crash, the signature is crash state, it is usually the
+      # top 3 crash functions seperated by '\n'.
+      signature_parts = self.signature.split('\n')
+
+      def _IsSignatureCallstack(callstack):
+        for index, frame in enumerate(callstack):
+          for signature_part in signature_parts:
+            if signature_part in frame.function:
+              return True, index
+
+        return False, 0
+
+      # Set the crash stack using signature callstack.
+      for callstack in self:
+        is_signature_callstack, index = _IsSignatureCallstack(callstack)
+        if is_signature_callstack:
+          # Filter all the stack frames before signature.
+          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