duktape-1.5.2/src-separate/duk_bi_function.c

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/*
 *  Function built-ins
 */
 
#include "duk_internal.h"
 
DUK_INTERNAL duk_ret_t duk_bi_function_constructor(duk_context *ctx) {
    duk_hthread *thr = (duk_hthread *) ctx;
    duk_hstring *h_sourcecode;
    duk_idx_t nargs;
    duk_idx_t i;
    duk_small_uint_t comp_flags;
    duk_hcompiledfunction *func;
    duk_hobject *outer_lex_env;
    duk_hobject *outer_var_env;
 
    /* normal and constructor calls have identical semantics */
 
    nargs = duk_get_top(ctx);
    for (i = 0; i < nargs; i++) {
        duk_to_string(ctx, i);
    }
 
    if (nargs == 0) {
        duk_push_string(ctx, "");
        duk_push_string(ctx, "");
    } else if (nargs == 1) {
        /* XXX: cover this with the generic >1 case? */
        duk_push_string(ctx, "");
    } else {
        duk_insert(ctx, 0);   /* [ arg1 ... argN-1 body] -> [body arg1 ... argN-1] */
        duk_push_string(ctx, ",");
        duk_insert(ctx, 1);
        duk_join(ctx, nargs - 1);
    }
 
    /* [ body formals ], formals is comma separated list that needs to be parsed */
 
    DUK_ASSERT_TOP(ctx, 2);
 
    /* XXX: this placeholder is not always correct, but use for now.
     * It will fail in corner cases; see test-dev-func-cons-args.js.
     */
    duk_push_string(ctx, "function(");
    duk_dup(ctx, 1);
    duk_push_string(ctx, "){");
    duk_dup(ctx, 0);
    duk_push_string(ctx, "}");
    duk_concat(ctx, 5);
 
    /* [ body formals source ] */
 
    DUK_ASSERT_TOP(ctx, 3);
 
    /* strictness is not inherited, intentional */
    comp_flags = DUK_JS_COMPILE_FLAG_FUNCEXPR;
 
    duk_push_hstring_stridx(ctx, DUK_STRIDX_COMPILE);  /* XXX: copy from caller? */  /* XXX: ignored now */
    h_sourcecode = duk_require_hstring(ctx, -2);
    duk_js_compile(thr,
                   (const duk_uint8_t *) DUK_HSTRING_GET_DATA(h_sourcecode),
                   (duk_size_t) DUK_HSTRING_GET_BYTELEN(h_sourcecode),
                   comp_flags);
    func = (duk_hcompiledfunction *) duk_get_hobject(ctx, -1);
    DUK_ASSERT(func != NULL);
    DUK_ASSERT(DUK_HOBJECT_IS_COMPILEDFUNCTION((duk_hobject *) func));
 
    /* [ body formals source template ] */
 
    /* only outer_lex_env matters, as functions always get a new
     * variable declaration environment.
     */
 
    outer_lex_env = thr->builtins[DUK_BIDX_GLOBAL_ENV];
    outer_var_env = thr->builtins[DUK_BIDX_GLOBAL_ENV];
 
    duk_js_push_closure(thr, func, outer_var_env, outer_lex_env, 1 /*add_auto_proto*/);
 
    /* [ body formals source template closure ] */
 
    return 1;
}
 
DUK_INTERNAL duk_ret_t duk_bi_function_prototype(duk_context *ctx) {
    /* ignore arguments, return undefined (E5 Section 15.3.4) */
    DUK_UNREF(ctx);
    return 0;
}
 
DUK_INTERNAL duk_ret_t duk_bi_function_prototype_to_string(duk_context *ctx) {
    duk_tval *tv;
 
    /*
     *  E5 Section 15.3.4.2 places few requirements on the output of
     *  this function:
     *
     *    - The result is an implementation dependent representation
     *      of the function; in particular
     *
     *    - The result must follow the syntax of a FunctionDeclaration.
     *      In particular, the function must have a name (even in the
     *      case of an anonymous function or a function with an empty
     *      name).
     *
     *    - Note in particular that the output does NOT need to compile
     *      into anything useful.
     */
 
 
    /* XXX: faster internal way to get this */
    duk_push_this(ctx);
    tv = duk_get_tval(ctx, -1);
    DUK_ASSERT(tv != NULL);
 
    if (DUK_TVAL_IS_OBJECT(tv)) {
        duk_hobject *obj = DUK_TVAL_GET_OBJECT(tv);
        const char *func_name;
 
        /* Function name: missing/undefined is mapped to empty string,
         * otherwise coerce to string.
         */
        /* XXX: currently no handling for non-allowed identifier characters,
         * e.g. a '{' in the function name.
         */
        duk_get_prop_stridx(ctx, -1, DUK_STRIDX_NAME);
        if (duk_is_undefined(ctx, -1)) {
            func_name = "";
        } else {
            func_name = duk_to_string(ctx, -1);
            DUK_ASSERT(func_name != NULL);
        }
 
        /* Indicate function type in the function body using a dummy
         * directive.
         */
        if (DUK_HOBJECT_HAS_COMPILEDFUNCTION(obj)) {
            duk_push_sprintf(ctx, "function %s() {\"ecmascript\"}", (const char *) func_name);
        } else if (DUK_HOBJECT_HAS_NATIVEFUNCTION(obj)) {
            duk_push_sprintf(ctx, "function %s() {\"native\"}", (const char *) func_name);
        } else if (DUK_HOBJECT_HAS_BOUND(obj)) {
            duk_push_sprintf(ctx, "function %s() {\"bound\"}", (const char *) func_name);
        } else {
            goto type_error;
        }
    } else if (DUK_TVAL_IS_LIGHTFUNC(tv)) {
        duk_push_lightfunc_tostring(ctx, tv);
    } else {
        goto type_error;
    }
 
    return 1;
 
 type_error:
    return DUK_RET_TYPE_ERROR;
}
 
DUK_INTERNAL duk_ret_t duk_bi_function_prototype_apply(duk_context *ctx) {
    duk_idx_t len;
    duk_idx_t i;
 
    DUK_ASSERT_TOP(ctx, 2);  /* not a vararg function */
 
    duk_push_this(ctx);
    if (!duk_is_callable(ctx, -1)) {
        DUK_DDD(DUK_DDDPRINT("func is not callable"));
        goto type_error;
    }
    duk_insert(ctx, 0);
    DUK_ASSERT_TOP(ctx, 3);
 
    DUK_DDD(DUK_DDDPRINT("func=%!iT, thisArg=%!iT, argArray=%!iT",
                         (duk_tval *) duk_get_tval(ctx, 0),
                         (duk_tval *) duk_get_tval(ctx, 1),
                         (duk_tval *) duk_get_tval(ctx, 2)));
 
    /* [ func thisArg argArray ] */
 
    if (duk_is_null_or_undefined(ctx, 2)) {
        DUK_DDD(DUK_DDDPRINT("argArray is null/undefined, no args"));
        len = 0;
    } else if (!duk_is_object(ctx, 2)) {
        goto type_error;
    } else {
        DUK_DDD(DUK_DDDPRINT("argArray is an object"));
 
        /* XXX: make this an internal helper */
        duk_get_prop_stridx(ctx, 2, DUK_STRIDX_LENGTH);
        len = (duk_idx_t) duk_to_uint32(ctx, -1);  /* ToUint32() coercion required */
        duk_pop(ctx);
 
        duk_require_stack(ctx, len);
 
        DUK_DDD(DUK_DDDPRINT("argArray length is %ld", (long) len));
        for (i = 0; i < len; i++) {
            duk_get_prop_index(ctx, 2, i);
        }
    }
    duk_remove(ctx, 2);
    DUK_ASSERT_TOP(ctx, 2 + len);
 
    /* [ func thisArg arg1 ... argN ] */
 
    DUK_DDD(DUK_DDDPRINT("apply, func=%!iT, thisArg=%!iT, len=%ld",
                         (duk_tval *) duk_get_tval(ctx, 0),
                         (duk_tval *) duk_get_tval(ctx, 1),
                         (long) len));
    duk_call_method(ctx, len);
    return 1;
 
 type_error:
    return DUK_RET_TYPE_ERROR;
}
 
DUK_INTERNAL duk_ret_t duk_bi_function_prototype_call(duk_context *ctx) {
    duk_idx_t nargs;
 
    /* Step 1 is not necessary because duk_call_method() will take
     * care of it.
     */
 
    /* vararg function, thisArg needs special handling */
    nargs = duk_get_top(ctx);  /* = 1 + arg count */
    if (nargs == 0) {
        duk_push_undefined(ctx);
        nargs++;
    }
    DUK_ASSERT(nargs >= 1);
 
    /* [ thisArg arg1 ... argN ] */
 
    duk_push_this(ctx);  /* 'func' in the algorithm */
    duk_insert(ctx, 0);
 
    /* [ func thisArg arg1 ... argN ] */
 
    DUK_DDD(DUK_DDDPRINT("func=%!iT, thisArg=%!iT, argcount=%ld, top=%ld",
                         (duk_tval *) duk_get_tval(ctx, 0),
                         (duk_tval *) duk_get_tval(ctx, 1),
                         (long) (nargs - 1),
                         (long) duk_get_top(ctx)));
    duk_call_method(ctx, nargs - 1);
    return 1;
}
 
/* XXX: the implementation now assumes "chained" bound functions,
 * whereas "collapsed" bound functions (where there is ever only
 * one bound function which directly points to a non-bound, final
 * function) would require a "collapsing" implementation which
 * merges argument lists etc here.
 */
DUK_INTERNAL duk_ret_t duk_bi_function_prototype_bind(duk_context *ctx) {
    duk_hobject *h_bound;
    duk_hobject *h_target;
    duk_idx_t nargs;
    duk_idx_t i;
 
    /* vararg function, careful arg handling (e.g. thisArg may not be present) */
    nargs = duk_get_top(ctx);  /* = 1 + arg count */
    if (nargs == 0) {
        duk_push_undefined(ctx);
        nargs++;
    }
    DUK_ASSERT(nargs >= 1);
 
    duk_push_this(ctx);
    if (!duk_is_callable(ctx, -1)) {
        DUK_DDD(DUK_DDDPRINT("func is not callable"));
        goto type_error;
    }
 
    /* [ thisArg arg1 ... argN func ]  (thisArg+args == nargs total) */
    DUK_ASSERT_TOP(ctx, nargs + 1);
 
    /* create bound function object */
    duk_push_object_helper(ctx,
                           DUK_HOBJECT_FLAG_EXTENSIBLE |
                           DUK_HOBJECT_FLAG_BOUND |
                           DUK_HOBJECT_FLAG_CONSTRUCTABLE |
                           DUK_HOBJECT_CLASS_AS_FLAGS(DUK_HOBJECT_CLASS_FUNCTION),
                           DUK_BIDX_FUNCTION_PROTOTYPE);
    h_bound = duk_get_hobject(ctx, -1);
    DUK_ASSERT(h_bound != NULL);
 
    /* [ thisArg arg1 ... argN func boundFunc ] */
    duk_dup(ctx, -2);  /* func */
    duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_INT_TARGET, DUK_PROPDESC_FLAGS_NONE);
 
    duk_dup(ctx, 0);   /* thisArg */
    duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_INT_THIS, DUK_PROPDESC_FLAGS_NONE);
 
    duk_push_array(ctx);
 
    /* [ thisArg arg1 ... argN func boundFunc argArray ] */
 
    for (i = 0; i < nargs - 1; i++) {
        duk_dup(ctx, 1 + i);
        duk_put_prop_index(ctx, -2, i);
    }
    duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_INT_ARGS, DUK_PROPDESC_FLAGS_NONE);
 
    /* [ thisArg arg1 ... argN func boundFunc ] */
 
    /* bound function 'length' property is interesting */
    h_target = duk_get_hobject(ctx, -2);
    if (h_target == NULL ||  /* lightfunc */
        DUK_HOBJECT_GET_CLASS_NUMBER(h_target) == DUK_HOBJECT_CLASS_FUNCTION) {
        /* For lightfuncs, simply read the virtual property. */
        duk_int_t tmp;
        duk_get_prop_stridx(ctx, -2, DUK_STRIDX_LENGTH);
        tmp = duk_to_int(ctx, -1) - (nargs - 1);  /* step 15.a */
        duk_pop(ctx);
        duk_push_int(ctx, (tmp < 0 ? 0 : tmp));
    } else {
        duk_push_int(ctx, 0);
    }
    duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_LENGTH, DUK_PROPDESC_FLAGS_NONE);  /* attrs in E5 Section 15.3.5.1 */
 
    /* caller and arguments must use the same thrower, [[ThrowTypeError]] */
    duk_xdef_prop_stridx_thrower(ctx, -1, DUK_STRIDX_CALLER, DUK_PROPDESC_FLAGS_NONE);
    duk_xdef_prop_stridx_thrower(ctx, -1, DUK_STRIDX_LC_ARGUMENTS, DUK_PROPDESC_FLAGS_NONE);
 
    /* these non-standard properties are copied for convenience */
    /* XXX: 'copy properties' API call? */
    duk_get_prop_stridx(ctx, -2, DUK_STRIDX_NAME);
    duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_NAME, DUK_PROPDESC_FLAGS_WC);
    duk_get_prop_stridx(ctx, -2, DUK_STRIDX_FILE_NAME);
    duk_xdef_prop_stridx(ctx, -2, DUK_STRIDX_FILE_NAME, DUK_PROPDESC_FLAGS_WC);
 
    /* The 'strict' flag is copied to get the special [[Get]] of E5.1
     * Section 15.3.5.4 to apply when a 'caller' value is a strict bound
     * function.  Not sure if this is correct, because the specification
     * is a bit ambiguous on this point but it would make sense.
     */
    if (h_target == NULL) {
        /* Lightfuncs are always strict. */
        DUK_HOBJECT_SET_STRICT(h_bound);
    } else if (DUK_HOBJECT_HAS_STRICT(h_target)) {
        DUK_HOBJECT_SET_STRICT(h_bound);
    }
    DUK_DDD(DUK_DDDPRINT("created bound function: %!iT", (duk_tval *) duk_get_tval(ctx, -1)));
 
    return 1;
 
 type_error:
    return DUK_RET_TYPE_ERROR;
}