# ------------------------------------------------------------------------------
# CodeHawk C Analyzer
# Author: Henny Sipma
# ------------------------------------------------------------------------------
# The MIT License (MIT)
#
# Copyright (c) 2017-2020 Kestrel Technology LLC
# Copyright (c) 2020-2022 Henny B. Sipma
# Copyright (c) 2023-2024 Aarno Labs LLC
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# SOFTWARE.
# ------------------------------------------------------------------------------
"""Assumption on the return value of a function represented by a predicate.
Assumptions about return values of functions are never 'imposed' like those on
function arguments by the receiving function. The reason is that different
functions may have different expectations about the postcondition of a function,
or the transfer relation of the function.
Necessary postconditions may be suggested with the open proof obligation as a
hint towards conditions that can then be imposed deliberately via a contract
assumption.
"""
from typing import Any, List, TYPE_CHECKING
if TYPE_CHECKING:
from chc.api.CFunctionApi import CFunctionApi
from chc.api.XPredicate import XPredicate
from chc.app.CFunction import CFunction
[docs]class ContractAssumption:
"""Post condition assumption or assumption on global variable.
Args:
capi (CFunctionApi): the function api of the function that
requests the assumption
id (int): identification number of the assumption
callee (int): (local) id of the function for which the
postcondition is requested (-1 for a request on a global
variable)
xpredicate (XPredicate): predicate representing the assumption
ppos (List[int]): id's of the primary proof obligations that
require this assumption for discharge
spos (List[int]): id's of the supporting proof obligations that
require this assumption for discharge
"""
def __init__(
self,
capi: "CFunctionApi",
id: int,
callee: int,
xpredicate: "XPredicate",
ppos: List[int],
spos: List[int]
) -> None:
self._id = id
self._callee = callee
self._capi = capi
self._cfun = self.capi.cfun
self._xpredicate = xpredicate
self._ppos = ppos
self._spos = spos
@property
def id(self) -> int:
return self._id
@property
def callee(self) -> int:
return self._callee
@property
def capi(self) -> "CFunctionApi":
return self._capi
@property
def xpredicate(self) -> "XPredicate":
return self._xpredicate
@property
def ppos(self) -> List[int]:
return self._ppos
@property
def spos(self) -> List[int]:
return self._spos
def __str__(self) -> str:
strppos = ""
strspos = ""
calleename = "global"
if self.callee >= 0:
calleename = self.capi.cfile.get_global_varinfo(self.callee).vname
if len(self.ppos) > 0:
strppos = (
"\n --Dependent ppo's: ["
+ ",".join(str(i) for i in self.ppos)
+ "]"
)
if len(self.spos) > 0:
strspos = (
"\n --Dependent spo's: ["
+ ",".join(str(i) for i in self.spos)
+ "]"
)
return calleename + ": " + str(self.xpredicate) + strppos + strspos