Qt.git - Qt s a cross-platform application framework that is used for developing application software that can be run on various software and hardware platforms with little or no change in the underlying codebase, while still being a native application with native capabilities and speed.

path: root/doc/src/snippets/code/src_gui_image_qimage.cpp

diff options

author	Qt Continuous Integration System <qt-info@nokia.com>	2010-11-24 14:15:16 (GMT)
committer	Qt Continuous Integration System <qt-info@nokia.com>	2010-11-24 14:15:16 (GMT)
commit	bdeb4b458320ddefc9bcd19620bed7dc242b4d5c (patch)
tree	51b995db1f4fec658adf9f644ce7590501d627ad /doc/src/snippets/code/src_gui_image_qimage.cpp
parent	caca740ea1219227008c303b5f2fac24af5a62a0 (diff)
parent	fe8276e812c5fdc690715d7e36a6b6d70cba7d33 (diff)
download	Qt-bdeb4b458320ddefc9bcd19620bed7dc242b4d5c.zip Qt-bdeb4b458320ddefc9bcd19620bed7dc242b4d5c.tar.gz Qt-bdeb4b458320ddefc9bcd19620bed7dc242b4d5c.tar.bz2

Merge branch '4.7' of scm.dev.nokia.troll.no:qt/qt-multimedia-staging into 4.7-integration

* '4.7' of scm.dev.nokia.troll.no:qt/qt-multimedia-staging: Prevent compilers optimizing eval timebomb code out of existence.

Diffstat (limited to 'doc/src/snippets/code/src_gui_image_qimage.cpp')

0 files changed, 0 insertions, 0 deletions

href='#n164'>164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038

/*
 * This file exposes PyAST_Validate interface to check the integrity
 * of the given abstract syntax tree (potentially constructed manually).
 */
#include "Python.h"
#include "pycore_ast.h"           // asdl_stmt_seq
#include "pycore_pystate.h"       // _PyThreadState_GET()

#include <assert.h>
#include <stdbool.h>

struct validator {
    int recursion_depth;            /* current recursion depth */
    int recursion_limit;            /* recursion limit */
};

static int validate_stmts(struct validator *, asdl_stmt_seq *);
static int validate_exprs(struct validator *, asdl_expr_seq *, expr_context_ty, int);
static int validate_patterns(struct validator *, asdl_pattern_seq *, int);
static int _validate_nonempty_seq(asdl_seq *, const char *, const char *);
static int validate_stmt(struct validator *, stmt_ty);
static int validate_expr(struct validator *, expr_ty, expr_context_ty);
static int validate_pattern(struct validator *, pattern_ty, int);

#define VALIDATE_POSITIONS(node) \
    if (node->lineno > node->end_lineno) { \
        PyErr_Format(PyExc_ValueError, \
                     "AST node line range (%d, %d) is not valid", \
                     node->lineno, node->end_lineno); \
        return 0; \
    } \
    if ((node->lineno < 0 && node->end_lineno != node->lineno) || \
        (node->col_offset < 0 && node->col_offset != node->end_col_offset)) { \
        PyErr_Format(PyExc_ValueError, \
                     "AST node column range (%d, %d) for line range (%d, %d) is not valid", \
                     node->col_offset, node->end_col_offset, node->lineno, node->end_lineno); \
        return 0; \
    } \
    if (node->lineno == node->end_lineno && node->col_offset > node->end_col_offset) { \
        PyErr_Format(PyExc_ValueError, \
                     "line %d, column %d-%d is not a valid range", \
                     node->lineno, node->col_offset, node->end_col_offset); \
        return 0; \
    }

static int
validate_name(PyObject *name)
{
    assert(PyUnicode_Check(name));
    static const char * const forbidden[] = {
        "None",
        "True",
        "False",
        NULL
    };
    for (int i = 0; forbidden[i] != NULL; i++) {
        if (_PyUnicode_EqualToASCIIString(name, forbidden[i])) {
            PyErr_Format(PyExc_ValueError, "identifier field can't represent '%s' constant", forbidden[i]);
            return 0;
        }
    }
    return 1;
}

static int
validate_comprehension(struct validator *state, asdl_comprehension_seq *gens)
{
    Py_ssize_t i;
    if (!asdl_seq_LEN(gens)) {
        PyErr_SetString(PyExc_ValueError, "comprehension with no generators");
        return 0;
    }
    for (i = 0; i < asdl_seq_LEN(gens); i++) {
        comprehension_ty comp = asdl_seq_GET(gens, i);
        if (!validate_expr(state, comp->target, Store) ||
            !validate_expr(state, comp->iter, Load) ||
            !validate_exprs(state, comp->ifs, Load, 0))
            return 0;
    }
    return 1;
}

static int
validate_keywords(struct validator *state, asdl_keyword_seq *keywords)
{
    Py_ssize_t i;
    for (i = 0; i < asdl_seq_LEN(keywords); i++)
        if (!validate_expr(state, (asdl_seq_GET(keywords, i))->value, Load))
            return 0;
    return 1;
}

static int
validate_args(struct validator *state, asdl_arg_seq *args)
{
    Py_ssize_t i;
    for (i = 0; i < asdl_seq_LEN(args); i++) {
        arg_ty arg = asdl_seq_GET(args, i);
        VALIDATE_POSITIONS(arg);
        if (arg->annotation && !validate_expr(state, arg->annotation, Load))
            return 0;
    }
    return 1;
}

static const char *
expr_context_name(expr_context_ty ctx)
{
    switch (ctx) {
    case Load:
        return "Load";
    case Store:
        return "Store";
    case Del:
        return "Del";
    // No default case so compiler emits warning for unhandled cases
    }
    Py_UNREACHABLE();
}

static int
validate_arguments(struct validator *state, arguments_ty args)
{
    if (!validate_args(state, args->posonlyargs) || !validate_args(state, args->args)) {
        return 0;
    }
    if (args->vararg && args->vararg->annotation
        && !validate_expr(state, args->vararg->annotation, Load)) {
            return 0;
    }
    if (!validate_args(state, args->kwonlyargs))
        return 0;
    if (args->kwarg && args->kwarg->annotation
        && !validate_expr(state, args->kwarg->annotation, Load)) {
            return 0;
    }
    if (asdl_seq_LEN(args->defaults) > asdl_seq_LEN(args->posonlyargs) + asdl_seq_LEN(args->args)) {
        PyErr_SetString(PyExc_ValueError, "more positional defaults than args on arguments");
        return 0;
    }
    if (asdl_seq_LEN(args->kw_defaults) != asdl_seq_LEN(args->kwonlyargs)) {
        PyErr_SetString(PyExc_ValueError, "length of kwonlyargs is not the same as "
                        "kw_defaults on arguments");
        return 0;
    }
    return validate_exprs(state, args->defaults, Load, 0) && validate_exprs(state, args->kw_defaults, Load, 1);
}

static int
validate_constant(struct validator *state, PyObject *value)
{
    if (value == Py_None || value == Py_Ellipsis)
        return 1;

    if (PyLong_CheckExact(value)
            || PyFloat_CheckExact(value)
            || PyComplex_CheckExact(value)
            || PyBool_Check(value)
            || PyUnicode_CheckExact(value)
            || PyBytes_CheckExact(value))
        return 1;

    if (PyTuple_CheckExact(value) || PyFrozenSet_CheckExact(value)) {
        if (++state->recursion_depth > state->recursion_limit) {
            PyErr_SetString(PyExc_RecursionError,
                            "maximum recursion depth exceeded during compilation");
            return 0;
        }

        PyObject *it = PyObject_GetIter(value);
        if (it == NULL)
            return 0;

        while (1) {
            PyObject *item = PyIter_Next(it);
            if (item == NULL) {
                if (PyErr_Occurred()) {
                    Py_DECREF(it);
                    return 0;
                }
                break;
            }

            if (!validate_constant(state, item)) {
                Py_DECREF(it);
                Py_DECREF(item);
                return 0;
            }
            Py_DECREF(item);
        }

        Py_DECREF(it);
        --state->recursion_depth;
        return 1;
    }

    if (!PyErr_Occurred()) {
        PyErr_Format(PyExc_TypeError,
                     "got an invalid type in Constant: %s",
                     _PyType_Name(Py_TYPE(value)));
    }
    return 0;
}

static int
validate_expr(struct validator *state, expr_ty exp, expr_context_ty ctx)
{
    VALIDATE_POSITIONS(exp);
    int ret = -1;
    if (++state->recursion_depth > state->recursion_limit) {
        PyErr_SetString(PyExc_RecursionError,
                        "maximum recursion depth exceeded during compilation");
        return 0;
    }
    int check_ctx = 1;
    expr_context_ty actual_ctx;

    /* First check expression context. */
    switch (exp->kind) {
    case Attribute_kind:
        actual_ctx = exp->v.Attribute.ctx;
        break;
    case Subscript_kind:
        actual_ctx = exp->v.Subscript.ctx;
        break;
    case Starred_kind:
        actual_ctx = exp->v.Starred.ctx;
        break;
    case Name_kind:
        if (!validate_name(exp->v.Name.id)) {
            return 0;
        }
        actual_ctx = exp->v.Name.ctx;
        break;
    case List_kind:
        actual_ctx = exp->v.List.ctx;
        break;
    case Tuple_kind:
        actual_ctx = exp->v.Tuple.ctx;
        break;
    default:
        if (ctx != Load) {
            PyErr_Format(PyExc_ValueError, "expression which can't be "
                         "assigned to in %s context", expr_context_name(ctx));
            return 0;
        }
        check_ctx = 0;
        /* set actual_ctx to prevent gcc warning */
        actual_ctx = 0;
    }
    if (check_ctx && actual_ctx != ctx) {
        PyErr_Format(PyExc_ValueError, "expression must have %s context but has %s instead",
                     expr_context_name(ctx), expr_context_name(actual_ctx));
        return 0;
    }

    /* Now validate expression. */
    switch (exp->kind) {
    case BoolOp_kind:
        if (asdl_seq_LEN(exp->v.BoolOp.values) < 2) {
            PyErr_SetString(PyExc_ValueError, "BoolOp with less than 2 values");
            return 0;
        }
        ret = validate_exprs(state, exp->v.BoolOp.values, Load, 0);
        break;
    case BinOp_kind:
        ret = validate_expr(state, exp->v.BinOp.left, Load) &&
            validate_expr(state, exp->v.BinOp.right, Load);
        break;
    case UnaryOp_kind:
        ret = validate_expr(state, exp->v.UnaryOp.operand, Load);
        break;
    case Lambda_kind:
        ret = validate_arguments(state, exp->v.Lambda.args) &&
            validate_expr(state, exp->v.Lambda.body, Load);
        break;
    case IfExp_kind:
        ret = validate_expr(state, exp->v.IfExp.test, Load) &&
            validate_expr(state, exp->v.IfExp.body, Load) &&
            validate_expr(state, exp->v.IfExp.orelse, Load);
        break;
    case Dict_kind:
        if (asdl_seq_LEN(exp->v.Dict.keys) != asdl_seq_LEN(exp->v.Dict.values)) {
            PyErr_SetString(PyExc_ValueError,
                            "Dict doesn't have the same number of keys as values");
            return 0;
        }
        /* null_ok=1 for keys expressions to allow dict unpacking to work in
           dict literals, i.e. ``{**{a:b}}`` */
        ret = validate_exprs(state, exp->v.Dict.keys, Load, /*null_ok=*/ 1) &&
            validate_exprs(state, exp->v.Dict.values, Load, /*null_ok=*/ 0);
        break;
    case Set_kind:
        ret = validate_exprs(state, exp->v.Set.elts, Load, 0);
        break;
#define COMP(NAME) \
        case NAME ## _kind: \
            ret = validate_comprehension(state, exp->v.NAME.generators) && \
                validate_expr(state, exp->v.NAME.elt, Load); \
            break;
    COMP(ListComp)
    COMP(SetComp)
    COMP(GeneratorExp)
#undef COMP
    case DictComp_kind:
        ret = validate_comprehension(state, exp->v.DictComp.generators) &&
            validate_expr(state, exp->v.DictComp.key, Load) &&
            validate_expr(state, exp->v.DictComp.value, Load);
        break;
    case Yield_kind:
        ret = !exp->v.Yield.value || validate_expr(state, exp->v.Yield.value, Load);
        break;
    case YieldFrom_kind:
        ret = validate_expr(state, exp->v.YieldFrom.value, Load);
        break;
    case Await_kind:
        ret = validate_expr(state, exp->v.Await.value, Load);
        break;
    case Compare_kind:
        if (!asdl_seq_LEN(exp->v.Compare.comparators)) {
            PyErr_SetString(PyExc_ValueError, "Compare with no comparators");
            return 0;
        }
        if (asdl_seq_LEN(exp->v.Compare.comparators) !=
            asdl_seq_LEN(exp->v.Compare.ops)) {
            PyErr_SetString(PyExc_ValueError, "Compare has a different number "
                            "of comparators and operands");
            return 0;
        }
        ret = validate_exprs(state, exp->v.Compare.comparators, Load, 0) &&
            validate_expr(state, exp->v.Compare.left, Load);
        break;
    case Call_kind:
        ret = validate_expr(state, exp->v.Call.func, Load) &&
            validate_exprs(state, exp->v.Call.args, Load, 0) &&
            validate_keywords(state, exp->v.Call.keywords);
        break;
    case Constant_kind:
        if (!validate_constant(state, exp->v.Constant.value)) {
            return 0;
        }
        ret = 1;
        break;
    case JoinedStr_kind:
        ret = validate_exprs(state, exp->v.JoinedStr.values, Load, 0);
        break;
    case FormattedValue_kind:
        if (validate_expr(state, exp->v.FormattedValue.value, Load) == 0)
            return 0;
        if (exp->v.FormattedValue.format_spec) {
            ret = validate_expr(state, exp->v.FormattedValue.format_spec, Load);
            break;
        }
        ret = 1;
        break;
    case Attribute_kind:
        ret = validate_expr(state, exp->v.Attribute.value, Load);
        break;
    case Subscript_kind:
        ret = validate_expr(state, exp->v.Subscript.slice, Load) &&
            validate_expr(state, exp->v.Subscript.value, Load);
        break;
    case Starred_kind:
        ret = validate_expr(state, exp->v.Starred.value, ctx);
        break;
    case Slice_kind:
        ret = (!exp->v.Slice.lower || validate_expr(state, exp->v.Slice.lower, Load)) &&
            (!exp->v.Slice.upper || validate_expr(state, exp->v.Slice.upper, Load)) &&
            (!exp->v.Slice.step || validate_expr(state, exp->v.Slice.step, Load));
        break;
    case List_kind:
        ret = validate_exprs(state, exp->v.List.elts, ctx, 0);
        break;
    case Tuple_kind:
        ret = validate_exprs(state, exp->v.Tuple.elts, ctx, 0);
        break;
    case NamedExpr_kind:
        ret = validate_expr(state, exp->v.NamedExpr.value, Load);
        break;
    /* This last case doesn't have any checking. */
    case Name_kind:
        ret = 1;
        break;
    // No default case so compiler emits warning for unhandled cases
    }
    if (ret < 0) {
        PyErr_SetString(PyExc_SystemError, "unexpected expression");
        ret = 0;
    }
    state->recursion_depth--;
    return ret;
}


// Note: the ensure_literal_* functions are only used to validate a restricted
//       set of non-recursive literals that have already been checked with
//       validate_expr, so they don't accept the validator state
static int
ensure_literal_number(expr_ty exp, bool allow_real, bool allow_imaginary)
{
    assert(exp->kind == Constant_kind);
    PyObject *value = exp->v.Constant.value;
    return (allow_real && PyFloat_CheckExact(value)) ||
           (allow_real && PyLong_CheckExact(value)) ||
           (allow_imaginary && PyComplex_CheckExact(value));
}

static int
ensure_literal_negative(expr_ty exp, bool allow_real, bool allow_imaginary)
{
    assert(exp->kind == UnaryOp_kind);
    // Must be negation ...
    if (exp->v.UnaryOp.op != USub) {
        return 0;
    }
    // ... of a constant ...
    expr_ty operand = exp->v.UnaryOp.operand;
    if (operand->kind != Constant_kind) {
        return 0;
    }
    // ... number
    return ensure_literal_number(operand, allow_real, allow_imaginary);
}

static int
ensure_literal_complex(expr_ty exp)
{
    assert(exp->kind == BinOp_kind);
    expr_ty left = exp->v.BinOp.left;
    expr_ty right = exp->v.BinOp.right;
    // Ensure op is addition or subtraction
    if (exp->v.BinOp.op != Add && exp->v.BinOp.op != Sub) {
        return 0;
    }
    // Check LHS is a real number (potentially signed)
    switch (left->kind)
    {
        case Constant_kind:
            if (!ensure_literal_number(left, /*real=*/true, /*imaginary=*/false)) {
                return 0;
            }
            break;
        case UnaryOp_kind:
            if (!ensure_literal_negative(left, /*real=*/true, /*imaginary=*/false)) {
                return 0;
            }
            break;
        default:
            return 0;
    }
    // Check RHS is an imaginary number (no separate sign allowed)
    switch (right->kind)
    {
        case Constant_kind:
            if (!ensure_literal_number(right, /*real=*/false, /*imaginary=*/true)) {
                return 0;
            }
            break;
        default:
            return 0;
    }
    return 1;
}

static int
validate_pattern_match_value(struct validator *state, expr_ty exp)
{
    if (!validate_expr(state, exp, Load)) {
        return 0;
    }

    switch (exp->kind)
    {
        case Constant_kind:
            /* Ellipsis and immutable sequences are not allowed.
               For True, False and None, MatchSingleton() should
               be used */
            if (!validate_expr(state, exp, Load)) {
                return 0;
            }
            PyObject *literal = exp->v.Constant.value;
            if (PyLong_CheckExact(literal) || PyFloat_CheckExact(literal) ||
                PyBytes_CheckExact(literal) || PyComplex_CheckExact(literal) ||
                PyUnicode_CheckExact(literal)) {
                return 1;
            }
            PyErr_SetString(PyExc_ValueError,
                            "unexpected constant inside of a literal pattern");
            return 0;
        case Attribute_kind:
            // Constants and attribute lookups are always permitted
            return 1;
        case UnaryOp_kind:
            // Negated numbers are permitted (whether real or imaginary)
            // Compiler will complain if AST folding doesn't create a constant
            if (ensure_literal_negative(exp, /*real=*/true, /*imaginary=*/true)) {
                return 1;
            }
            break;
        case BinOp_kind:
            // Complex literals are permitted
            // Compiler will complain if AST folding doesn't create a constant
            if (ensure_literal_complex(exp)) {
                return 1;
            }
            break;
        case JoinedStr_kind:
            // Handled in the later stages
            return 1;
        default:
            break;
    }
    PyErr_SetString(PyExc_ValueError,
                    "patterns may only match literals and attribute lookups");
    return 0;
}

static int
validate_capture(PyObject *name)
{
    if (_PyUnicode_EqualToASCIIString(name, "_")) {
        PyErr_Format(PyExc_ValueError, "can't capture name '_' in patterns");
        return 0;
    }
    return validate_name(name);
}

static int
validate_pattern(struct validator *state, pattern_ty p, int star_ok)
{
    VALIDATE_POSITIONS(p);
    int ret = -1;
    if (++state->recursion_depth > state->recursion_limit) {
        PyErr_SetString(PyExc_RecursionError,
                        "maximum recursion depth exceeded during compilation");
        return 0;
    }
    switch (p->kind) {
        case MatchValue_kind:
            ret = validate_pattern_match_value(state, p->v.MatchValue.value);
            break;
        case MatchSingleton_kind:
            ret = p->v.MatchSingleton.value == Py_None || PyBool_Check(p->v.MatchSingleton.value);
            if (!ret) {
                PyErr_SetString(PyExc_ValueError,
                                "MatchSingleton can only contain True, False and None");
            }
            break;
        case MatchSequence_kind:
            ret = validate_patterns(state, p->v.MatchSequence.patterns, /*star_ok=*/1);
            break;
        case MatchMapping_kind:
            if (asdl_seq_LEN(p->v.MatchMapping.keys) != asdl_seq_LEN(p->v.MatchMapping.patterns)) {
                PyErr_SetString(PyExc_ValueError,
                                "MatchMapping doesn't have the same number of keys as patterns");
                ret = 0;
                break;
            }

            if (p->v.MatchMapping.rest && !validate_capture(p->v.MatchMapping.rest)) {
                ret = 0;
                break;
            }

            asdl_expr_seq *keys = p->v.MatchMapping.keys;
            for (Py_ssize_t i = 0; i < asdl_seq_LEN(keys); i++) {
                expr_ty key = asdl_seq_GET(keys, i);
                if (key->kind == Constant_kind) {
                    PyObject *literal = key->v.Constant.value;
                    if (literal == Py_None || PyBool_Check(literal)) {
                        /* validate_pattern_match_value will ensure the key
                           doesn't contain True, False and None but it is
                           syntactically valid, so we will pass those on in
                           a special case. */
                        continue;
                    }
                }
                if (!validate_pattern_match_value(state, key)) {
                    ret = 0;
                    break;
                }
            }

            ret = validate_patterns(state, p->v.MatchMapping.patterns, /*star_ok=*/0);
            break;
        case MatchClass_kind:
            if (asdl_seq_LEN(p->v.MatchClass.kwd_attrs) != asdl_seq_LEN(p->v.MatchClass.kwd_patterns)) {
                PyErr_SetString(PyExc_ValueError,
                                "MatchClass doesn't have the same number of keyword attributes as patterns");
                ret = 0;
                break;
            }
            if (!validate_expr(state, p->v.MatchClass.cls, Load)) {
                ret = 0;
                break;
            }

            expr_ty cls = p->v.MatchClass.cls;
            while (1) {
                if (cls->kind == Name_kind) {
                    break;
                }
                else if (cls->kind == Attribute_kind) {
                    cls = cls->v.Attribute.value;
                    continue;
                }
                else {
                    PyErr_SetString(PyExc_ValueError,
                                    "MatchClass cls field can only contain Name or Attribute nodes.");
                    ret = 0;
                    break;
                }
            }

            for (Py_ssize_t i = 0; i < asdl_seq_LEN(p->v.MatchClass.kwd_attrs); i++) {
                PyObject *identifier = asdl_seq_GET(p->v.MatchClass.kwd_attrs, i);
                if (!validate_name(identifier)) {
                    ret = 0;
                    break;
                }
            }

            if (!validate_patterns(state, p->v.MatchClass.patterns, /*star_ok=*/0)) {
                ret = 0;
                break;
            }

            ret = validate_patterns(state, p->v.MatchClass.kwd_patterns, /*star_ok=*/0);
            break;
        case MatchStar_kind:
            if (!star_ok) {
                PyErr_SetString(PyExc_ValueError, "can't use MatchStar here");
                ret = 0;
                break;
            }
            ret = p->v.MatchStar.name == NULL || validate_capture(p->v.MatchStar.name);
            break;
        case MatchAs_kind:
            if (p->v.MatchAs.name && !validate_capture(p->v.MatchAs.name)) {
                ret = 0;
                break;
            }
            if (p->v.MatchAs.pattern == NULL) {
                ret = 1;
            }
            else if (p->v.MatchAs.name == NULL) {
                PyErr_SetString(PyExc_ValueError,
                                "MatchAs must specify a target name if a pattern is given");
                ret = 0;
            }
            else {
                ret = validate_pattern(state, p->v.MatchAs.pattern, /*star_ok=*/0);
            }
            break;
        case MatchOr_kind:
            if (asdl_seq_LEN(p->v.MatchOr.patterns) < 2) {
                PyErr_SetString(PyExc_ValueError,
                                "MatchOr requires at least 2 patterns");
                ret = 0;
                break;
            }
            ret = validate_patterns(state, p->v.MatchOr.patterns, /*star_ok=*/0);
            break;
    // No default case, so the compiler will emit a warning if new pattern
    // kinds are added without being handled here
    }
    if (ret < 0) {
        PyErr_SetString(PyExc_SystemError, "unexpected pattern");
        ret = 0;
    }
    state->recursion_depth--;
    return ret;
}

static int
_validate_nonempty_seq(asdl_seq *seq, const char *what, const char *owner)
{
    if (asdl_seq_LEN(seq))
        return 1;
    PyErr_Format(PyExc_ValueError, "empty %s on %s", what, owner);
    return 0;
}
#define validate_nonempty_seq(seq, what, owner) _validate_nonempty_seq((asdl_seq*)seq, what, owner)

static int
validate_assignlist(struct validator *state, asdl_expr_seq *targets, expr_context_ty ctx)
{
    return validate_nonempty_seq(targets, "targets", ctx == Del ? "Delete" : "Assign") &&
        validate_exprs(state, targets, ctx, 0);
}

static int
validate_body(struct validator *state, asdl_stmt_seq *body, const char *owner)
{
    return validate_nonempty_seq(body, "body", owner) && validate_stmts(state, body);
}

static int
validate_stmt(struct validator *state, stmt_ty stmt)
{
    VALIDATE_POSITIONS(stmt);
    int ret = -1;
    Py_ssize_t i;
    if (++state->recursion_depth > state->recursion_limit) {
        PyErr_SetString(PyExc_RecursionError,
                        "maximum recursion depth exceeded during compilation");
        return 0;
    }
    switch (stmt->kind) {
    case FunctionDef_kind:
        ret = validate_body(state, stmt->v.FunctionDef.body, "FunctionDef") &&
            validate_arguments(state, stmt->v.FunctionDef.args) &&
            validate_exprs(state, stmt->v.FunctionDef.decorator_list, Load, 0) &&
            (!stmt->v.FunctionDef.returns ||
             validate_expr(state, stmt->v.FunctionDef.returns, Load));
        break;
    case ClassDef_kind:
        ret = validate_body(state, stmt->v.ClassDef.body, "ClassDef") &&
            validate_exprs(state, stmt->v.ClassDef.bases, Load, 0) &&
            validate_keywords(state, stmt->v.ClassDef.keywords) &&
            validate_exprs(state, stmt->v.ClassDef.decorator_list, Load, 0);
        break;
    case Return_kind:
        ret = !stmt->v.Return.value || validate_expr(state, stmt->v.Return.value, Load);
        break;
    case Delete_kind:
        ret = validate_assignlist(state, stmt->v.Delete.targets, Del);
        break;
    case Assign_kind:
        ret = validate_assignlist(state, stmt->v.Assign.targets, Store) &&
            validate_expr(state, stmt->v.Assign.value, Load);
        break;
    case AugAssign_kind:
        ret = validate_expr(state, stmt->v.AugAssign.target, Store) &&
            validate_expr(state, stmt->v.AugAssign.value, Load);
        break;
    case AnnAssign_kind:
        if (stmt->v.AnnAssign.target->kind != Name_kind &&
            stmt->v.AnnAssign.simple) {
            PyErr_SetString(PyExc_TypeError,
                            "AnnAssign with simple non-Name target");
            return 0;
        }
        ret = validate_expr(state, stmt->v.AnnAssign.target, Store) &&
               (!stmt->v.AnnAssign.value ||
                validate_expr(state, stmt->v.AnnAssign.value, Load)) &&
               validate_expr(state, stmt->v.AnnAssign.annotation, Load);
        break;
    case For_kind:
        ret = validate_expr(state, stmt->v.For.target, Store) &&
            validate_expr(state, stmt->v.For.iter, Load) &&
            validate_body(state, stmt->v.For.body, "For") &&
            validate_stmts(state, stmt->v.For.orelse);
        break;
    case AsyncFor_kind:
        ret = validate_expr(state, stmt->v.AsyncFor.target, Store) &&
            validate_expr(state, stmt->v.AsyncFor.iter, Load) &&
            validate_body(state, stmt->v.AsyncFor.body, "AsyncFor") &&
            validate_stmts(state, stmt->v.AsyncFor.orelse);
        break;
    case While_kind:
        ret = validate_expr(state, stmt->v.While.test, Load) &&
            validate_body(state, stmt->v.While.body, "While") &&
            validate_stmts(state, stmt->v.While.orelse);
        break;
    case If_kind:
        ret = validate_expr(state, stmt->v.If.test, Load) &&
            validate_body(state, stmt->v.If.body, "If") &&
            validate_stmts(state, stmt->v.If.orelse);
        break;
    case With_kind:
        if (!validate_nonempty_seq(stmt->v.With.items, "items", "With"))
            return 0;
        for (i = 0; i < asdl_seq_LEN(stmt->v.With.items); i++) {
            withitem_ty item = asdl_seq_GET(stmt->v.With.items, i);
            if (!validate_expr(state, item->context_expr, Load) ||
                (item->optional_vars && !validate_expr(state, item->optional_vars, Store)))
                return 0;
        }
        ret = validate_body(state, stmt->v.With.body, "With");
        break;
    case AsyncWith_kind:
        if (!validate_nonempty_seq(stmt->v.AsyncWith.items, "items", "AsyncWith"))


context:
space:
mode: