dexter/dex/command/commands/DexExpectProgramState.py

# DExTer : Debugging Experience Tester
# ~~~~~~   ~         ~~         ~   ~~
#
# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
# See https://llvm.org/LICENSE.txt for license information.
# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
"""Command for specifying a partial or complete state for the program to enter
during execution.
"""

from itertools import chain

from dex.command.CommandBase import CommandBase
from dex.dextIR import ProgramState, SourceLocation, StackFrame, DextIR

def frame_from_dict(source: dict) -> StackFrame:
    if 'location' in source:
        assert isinstance(source['location'], dict)
        source['location'] = SourceLocation(**source['location'])
    return StackFrame(**source)

def state_from_dict(source: dict) -> ProgramState:
    if 'frames' in source:
        assert isinstance(source['frames'], list)
        source['frames'] = list(map(frame_from_dict, source['frames']))
    return ProgramState(**source)

class DexExpectProgramState(CommandBase):
    """Expect to see a given program `state` a certain numer of `times`.

    DexExpectProgramState(state [,**times])

    See Commands.md for more info.
    """

    def __init__(self, *args, **kwargs):
        if len(args) != 1:
            raise TypeError('expected exactly one unnamed arg')

        self.program_state_text = str(args[0])

        self.expected_program_state = state_from_dict(args[0])

        self.times = kwargs.pop('times', -1)
        if kwargs:
            raise TypeError('unexpected named args: {}'.format(
                ', '.join(kwargs)))

        # Step indices at which the expected program state was encountered.
        self.encounters = []

        super(DexExpectProgramState, self).__init__()

    @staticmethod
    def get_name():
        return __class__.__name__

    def get_watches(self):
        frame_expects = chain.from_iterable(frame.watches
            for frame in self.expected_program_state.frames)
        return set(frame_expects)

    def eval(self, step_collection: DextIR) -> bool:
        for step in step_collection.steps:
            if self.expected_program_state.match(step.program_state):
                self.encounters.append(step.step_index)

        return self.times < 0 < len(self.encounters) or len(self.encounters) == self.times