pgames-manager/backend/app/pgvn.py

"""Validation of the expression/statement AST accepted by the web interpreter."""


def expression(value, depth=0):
    if depth > 64 or not isinstance(value, dict):
        raise ValueError("Некорректное PGVN-выражение")
    kind = value.get("k")

    def ex(key, optional=False):
        v = value.get(key)
        if not optional or v is not None:
            expression(v, depth + 1)

    def seq(key):
        v = value.get(key)
        if not isinstance(v, list):
            raise ValueError(f"Выражение {kind}: нужен список {key}")
        return v

    if kind == "nani":
        nani_expression(value.get("ast"), depth + 1)
    elif kind == "const":
        if "v" not in value:
            raise ValueError("const без значения")
    elif kind == "name":
        if not isinstance(value.get("id"), str):
            raise ValueError("Имя переменной должно быть строкой")
    elif kind == "attr":
        ex("o")
        if not isinstance(value.get("a"), str):
            raise ValueError("Атрибут должен быть строкой")
    elif kind in ("sub", "slice"):
        ex("o")
        if kind == "sub":
            ex("i")
        else:
            for key in ("lo", "hi", "st"):
                ex(key, True)
    elif kind in ("bin", "unary", "bool"):
        from app.converter.pyexpr import BIN_OPS, UNARY_OPS
        allowed = set(BIN_OPS.values()) if kind == "bin" else set(UNARY_OPS.values()) if kind == "unary" else {"and", "or"}
        if value.get("op") not in allowed:
            raise ValueError("Неизвестная операция выражения")
        if kind == "bin":
            ex("l")
            ex("r")
        elif kind == "unary":
            ex("v")
        else:
            for item in seq("v"):
                expression(item, depth + 1)
    elif kind == "cmp":
        from app.converter.pyexpr import CMP_OPS
        ex("l")
        operators, operands = seq("ops"), seq("r")
        if len(operators) != len(operands) or any(op not in CMP_OPS.values() for op in operators):
            raise ValueError("Некорректное сравнение")
        for item in operands:
            expression(item, depth + 1)
    elif kind == "if":
        for key in ("c", "t", "e"):
            ex(key)
    elif kind in ("list", "tuple", "fmt", "dict"):
        for item in seq("v"):
            if kind == "dict":
                if not isinstance(item, list) or len(item) != 2:
                    raise ValueError("Некорректная запись словаря")
                for part in item:
                    expression(part, depth + 1)
            elif kind != "fmt" or not isinstance(item, str):
                expression(item, depth + 1)
    elif kind == "star":
        ex("v")
    elif kind == "lambda":
        parameters(value.get("params"), depth + 1)
        ex("body")
    elif kind == "call":
        ex("f")
        for item in seq("a"):
            expression(item, depth + 1)
        for item in value.get("ks", []):
            expression(item, depth + 1)
        if not isinstance(value.get("kw"), dict):
            raise ValueError("Некорректные аргументы вызова")
        for item in value["kw"].values():
            expression(item, depth + 1)
    elif kind == "comp":
        for key in ("e", "t", "it"):
            ex(key)
        for item in seq("if"):
            expression(item, depth + 1)
    else:
        raise ValueError(f"Неизвестное выражение: {kind}")


def parameters(params, depth):
    if not isinstance(params, list) or len(params) > 64:
        raise ValueError("Некорректные параметры функции")
    for p in params:
        if not isinstance(p, dict) or not isinstance(p.get("n"), str) or p.get("kind") not in ("p", "k", "*", "**"):
            raise ValueError("Некорректный параметр функции")
        if p.get("d") is not None:
            expression(p["d"], depth + 1)


def statements(code, depth=0):
    if depth > 64 or not isinstance(code, list):
        raise ValueError("Некорректный PGVN AST")
    for s in code:
        if not isinstance(s, dict):
            raise ValueError("Некорректный оператор AST")
        op = s.get("op")
        keys = {"set": ("t", "v"), "aug": ("t", "v"), "eval": ("e",),
                "if": ("c",), "while": ("c",), "for": ("t", "it"),
                "del": ("t",), "break": (), "continue": (), "def": (), "class": (),
                "return": (), "global": (), "nonlocal": ()}
        if op not in keys:
            raise ValueError(f"Неизвестный оператор AST: {op}")
        for key in keys[op]:
            expression(s.get(key), depth + 1)
        if op == "if":
            statements(s.get("then"), depth + 1)
            statements(s.get("else"), depth + 1)
        if op in ("while", "for"):
            statements(s.get("body"), depth + 1)
        if op == "def":
            if not isinstance(s.get("name"), str):
                raise ValueError("У функции нет имени")
            parameters(s.get("params"), depth + 1)
            statements(s.get("body"), depth + 1)
            for item in s.get("decos", []):
                expression(item, depth + 1)
        if op == "class":
            if not isinstance(s.get("name"), str):
                raise ValueError("У класса нет имени")
            for item in s.get("bases", []):
                expression(item, depth + 1)
            statements(s.get("body"), depth + 1)
        if op == "return" and s.get("v") is not None:
            expression(s["v"], depth + 1)
        if op in ("global", "nonlocal") and not (
                isinstance(s.get("names"), list) and all(isinstance(n, str) for n in s["names"])):
            raise ValueError("Некорректный список имён")


def nani_expression(node, depth=0):
    """Validate the optional Naninovel AST already supported by the shared player."""
    if depth > 64 or not isinstance(node, list) or not node:
        raise ValueError("Некорректный AST Naninovel")
    kind = node[0]
    if kind == "const" and len(node) == 2 and (node[1] is None or isinstance(node[1], (str, int, float, bool))):
        return
    if kind == "name" and len(node) == 2 and isinstance(node[1], str):
        return
    children = None
    if kind == "unary" and len(node) == 3 and node[1] in ("!", "not", "+", "-", "~"):
        children = node[2:]
    elif kind == "bin" and len(node) == 4:
        from app.converter.nani_expr import PRECEDENCE
        if node[1] in PRECEDENCE:
            children = node[2:]
    elif kind == "if" and len(node) == 4:
        children = node[1:]
    elif kind == "call" and len(node) == 3:
        from app.converter.nani_expr import FUNCTIONS
        if node[1] in FUNCTIONS and isinstance(node[2], list):
            children = node[2]
    if children is None:
        raise ValueError("Неизвестная операция AST Naninovel")
    for child in children:
        nani_expression(child, depth + 1)