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# CodeQ: an online programming tutor.
# Copyright (C) 2015 UL FRI
#
# This program is free software: you can redistribute it and/or modify it under
# the terms of the GNU Affero General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option) any
# later version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
# details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import operator
import os.path
import pickle
import threading
from db.models import CodeqUser, Problem
from db.util import make_identifier
import monkey
import prolog.engine
from prolog.util import used_predicates
import server
import server.user_session
from server.problems import get_facts, load_language, load_problem, solutions_for_problems
__all__ = ['PrologSession']
def format_prolog_output(reply, output):
messages = [text for text in map(operator.itemgetter(1), output)]
# When an engine is destroyed, a nested data object has the actual query result.
event = reply['event']
if event == 'destroy':
reply = reply['data']
event = reply['event']
if event == 'success':
messages.append(prolog.engine.pretty_vars(reply['data'][0]))
return messages, 'ok', True and reply['more']
if event == 'failure':
messages.append('false')
return messages, 'ok', False
if event == 'error':
# Remove potential module name (engine ID) from the error message.
messages.append('error: ' + reply['data'].replace("'{}':".format(reply['id']), ''))
return messages, 'error', False
return messages, 'ok', False # TODO: is it possible to reach this return statement?
class PrologSession(server.LanguageSession):
"""Abstracts a Prolog session.
Only public methods are available to the outside world due to the use of multiprocessing managers.
Therefore prefix any private methods with an underscore (_).
No properties are accessible; use getters and setters instead.
Values are passed by value instead of by reference (deep copy!).
"""
def __init__(self):
self._access_lock = threading.Lock()
self._engine_id = None
self._problem_id = -1
self._sent_hints = []
def run(self, code):
with self._access_lock:
if self._engine_id is not None:
prolog.engine.stop(self._engine_id)
self._engine_id = None
engine_id, output = prolog.engine.create(code=code)
if not engine_id:
raise Exception('System error: could not create a prolog engine')
self._engine_id = engine_id
messages = [text for text in map(operator.itemgetter(1), output)]
status = 'error' if 'error' in map(operator.itemgetter(0), output) else 'ok'
return messages, status, False
def query(self, query):
with self._access_lock:
if self._engine_id is None:
return ['Prolog is not running'], 'error', False
try:
return format_prolog_output(*prolog.engine.ask(self._engine_id, query))
except Exception as e:
return [str(e)], 'error', False
def step(self):
with self._access_lock:
if self._engine_id is None:
return ['Prolog is not running'], 'error', False
try:
return format_prolog_output(*prolog.engine.next(self._engine_id))
except Exception as e:
return [str(e)], 'error', False
def destroy(self): # this method was previously named: end()
"""Stops the Prolog engine."""
with self._access_lock:
if self._engine_id is not None:
prolog.engine.destroy(self._engine_id)
self._engine_id = None
self._problem_id = -1
return [], 'ok', False
def __del__(self):
# no locking needed if GC is removing us, as there cannot be any concurrent access by definition
if hasattr(self, '_engine_id') and (self._engine_id is not None):
prolog.engine.destroy(self._engine_id)
self._engine_id = None
def hint(self, sid, problem_id, program):
session = server.user_session.get_session_by_id(sid)
problem = Problem.get(id=problem_id)
language_module = load_language(problem.language, 'common')
problem_module = load_problem(problem.language, problem.group, problem.identifier, 'common')
aux_code = self._aux_code(session.get_uid(), problem, program)
hints = []
try:
# check if the program is already correct
n_correct, n_all, _ = problem_module.test(program, aux_code=aux_code)
if n_correct == n_all:
hints = [{'id': 'program_already_correct'}]
if not hints and hasattr(language_module, 'hint'):
hints = language_module.hint(program, aux_code=aux_code)
if not hints and hasattr(problem_module, 'hint'):
hints = problem_module.hint(program, aux_code=aux_code)
if not hints and problem_id in _edits:
# Testing function for monkey.
def tester(code):
n_correct, n_all, _ = problem_module.test(code, aux_code=aux_code)
return n_correct, n_all
solution, steps, fix_time, n_tested = monkey.fix(
program, _edits[problem_id], tester, timeout=5, debug=True)
if solution and steps:
hints = [{'id': 'monkey_main'}] + monkey.fix_hints(program, steps)
if not hints:
hints = [{'id': 'no_hint'}]
except Exception as ex:
hints = [{'id': 'system_error', 'args': {'message': str(ex)}}]
self._instantiate_and_save_hints(language_module, problem_module, hints)
return hints
def test(self, sid, problem_id, program):
session = server.user_session.get_session_by_id(sid)
problem = Problem.get(id=problem_id)
language_module = load_language(problem.language, 'common')
problem_module = load_problem(problem.language, problem.group, problem.identifier, 'common')
aux_code = self._aux_code(session.get_uid(), problem, program)
try:
n_correct, n_all, hints = problem_module.test(program, aux_code=aux_code)
if n_correct == n_all:
session.update_solution(problem_id, done=True)
except AttributeError as ex:
hints = [{'id': 'system_error', 'args': {'message': 'test function does not exist'}}]
except Exception as ex:
hints = [{'id': 'system_error', 'args': {'message': str(ex)}}]
self._instantiate_and_save_hints(language_module, problem_module, hints)
return hints
# Return a string with definitions of aux. predicates used in [program]
# (but only those that the user has already solved) and any required facts.
def _aux_code(self, user_id, problem, program):
problem_module = load_problem(problem.language, problem.group, problem.identifier, 'common')
used_predicate_identifiers = {make_identifier(name) for name in used_predicates(program)}
dependencies = {p for p in CodeqUser.solved_problems(user_id, problem.language)
if p[1] != problem.identifier and p[1] in used_predicate_identifiers}
return ('\n' + solutions_for_problems(problem.language, dependencies) +
'\n' + get_facts(problem.language, problem_module))
# Add hint parameters (such as message index) based on hint class. Append
# the finalized hints to the list of sent hints.
def _instantiate_and_save_hints(self, language_mod, problem_mod, hints):
with self._access_lock:
for hint in hints:
for mod in [language_mod, problem_mod]:
if hasattr(mod, 'hint_type') and hint['id'] in mod.hint_type:
hint_type = mod.hint_type[hint['id']]
hint_type.instantiate(hint, self._sent_hints)
self._sent_hints.extend(hints)
def run_for_user(self, user_id, problem_id, program, query):
"""A "shorthand" method to start a Prolog session, load correct solutions of all user's solved
problems and the given program, and ask a query.
"""
problem = Problem.get(id=problem_id)
aux_code = self._aux_code(user_id, problem, program)
messages, status, have_more = self.run(program+aux_code)
if status == 'ok':
more_messages, status, have_more = self.query(query)
messages.extend(more_messages)
self._problem_id = problem_id
return messages, status, have_more
server.language_session_handlers['prolog'] = lambda user_session, problem_id, language_identifier, group_identifier, problem_identifier: PrologSession()
# Load edit data.
try:
_edits, _submissions, _queries = pickle.load(
open(os.path.join(os.path.dirname(os.path.realpath(__file__)), '..', 'edits.pickle'), 'rb'))
except:
_edits = {}
_submissions = {}
_queries = {}
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