#!/usr/bin/env python

# This script uses a regex to validate the output of our backtraces.
# The layout we assume is:
#
# <frame number> <library name> <address> <demangled name> + <offset>
#
# It currently just checks that the backtrace results in at least one correctly
# formatted entry. It does not directly validate the input since the output
# would not be robust against standard library changes.
#
# TODO: We could have the user pass in the frame number, library name, and
# demangled name. These we can always validate as true in a robust way. On the
# other hand, address and offset are more difficult to validate in a robust way
# in the face of small codegen differences, so without any further thought I
# imagine we can just check the format.
#
# 11 libswiftCore.dylib 0x000000000dce84d0l _fatalErrorMessage(StaticString,
# StaticString, StaticString, UInt, flags : UInt32) -> () + 444

import re
import sys

TARGET_RE = re.compile(
    "(?P<index>\d+) +(?P<object>\S+) +(?P<address>0x[0-9a-fA-F]{16}) "
    "(?P<routine>[^+]+) [+] (?P<offset>\d+)")

lines = sys.stdin.readlines()

found_stack_trace_start = False
found_stack_trace_entry = False
for l in lines:
    l = l.rstrip("\n")

    # First see if we found the start of our stack trace start. If so, set the
    # found stack trace flag and continue.
    if l == "Current stack trace:":
        assert(not found_stack_trace_start)
        found_stack_trace_start = True
        continue

    # Otherwise, if we have not yet found the stack trace start, continue. We
    # need to find the stack trace start line.
    if not found_stack_trace_start:
        continue

    # Ok, we are in the middle of matching a stack trace entry.
    m = TARGET_RE.match(l)
    # If we fail to match, we have exited the stack trace entry region
    if m is None:
        break
    # At this point, we know that we have some sort of match.
    found_stack_trace_entry = True
    print("Stack Trace Entry:")
    print("\tIndex: '%(index)s'\n\tObject File: '%(object)s'\n\tAddress: "
          "'%(address)s'\n\tRoutine: '%(routine)s'\n\tOffset: '%(offset)s'"
          "\n" % m.groupdict())

# Once we have processed all of the lines, make sure that we found at least one
# stack trace entry.
assert(found_stack_trace_entry)