Sweden-Number/dlls/jscript/function.c

/*
 * Copyright 2008 Jacek Caban for CodeWeavers
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

#include <assert.h>

#include "jscript.h"
#include "engine.h"

#include "wine/debug.h"

WINE_DEFAULT_DEBUG_CHANNEL(jscript);

typedef struct {
    jsdisp_t dispex;
    builtin_invoke_t value_proc;
    const WCHAR *name;
    DWORD flags;
    scope_chain_t *scope_chain;
    bytecode_t *code;
    function_code_t *func_code;
    DWORD length;
} FunctionInstance;

typedef struct {
    jsdisp_t jsdisp;
    FunctionInstance *function;
    jsval_t *buf;
    call_frame_t *frame;
    unsigned argc;
} ArgumentsInstance;

static inline FunctionInstance *function_from_jsdisp(jsdisp_t *jsdisp)
{
    return CONTAINING_RECORD(jsdisp, FunctionInstance, dispex);
}

static inline FunctionInstance *function_from_vdisp(vdisp_t *vdisp)
{
    return function_from_jsdisp(vdisp->u.jsdisp);
}

static inline FunctionInstance *function_this(vdisp_t *jsthis)
{
    return is_vclass(jsthis, JSCLASS_FUNCTION) ? function_from_vdisp(jsthis) : NULL;
}

static inline ArgumentsInstance *arguments_from_jsdisp(jsdisp_t *jsdisp)
{
    return CONTAINING_RECORD(jsdisp, ArgumentsInstance, jsdisp);
}

static const WCHAR prototypeW[] = {'p','r','o','t','o','t', 'y', 'p','e',0};

static const WCHAR lengthW[] = {'l','e','n','g','t','h',0};
static const WCHAR toStringW[] = {'t','o','S','t','r','i','n','g',0};
static const WCHAR applyW[] = {'a','p','p','l','y',0};
static const WCHAR callW[] = {'c','a','l','l',0};
static const WCHAR argumentsW[] = {'a','r','g','u','m','e','n','t','s',0};

static HRESULT Arguments_value(script_ctx_t *ctx, vdisp_t *jsthis, WORD flags, unsigned argc, jsval_t *argv,
        jsval_t *r)
{
    FIXME("\n");
    return E_NOTIMPL;
}

static void Arguments_destructor(jsdisp_t *jsdisp)
{
    ArgumentsInstance *arguments = arguments_from_jsdisp(jsdisp);

    TRACE("(%p)\n", arguments);

    if(arguments->buf) {
        unsigned i;
        for(i = 0; i < arguments->argc; i++)
            jsval_release(arguments->buf[i]);
        heap_free(arguments->buf);
    }

    jsdisp_release(&arguments->function->dispex);
    heap_free(arguments);
}

static unsigned Arguments_idx_length(jsdisp_t *jsdisp)
{
    ArgumentsInstance *arguments = arguments_from_jsdisp(jsdisp);
    return arguments->argc;
}

static jsval_t *get_argument_ref(ArgumentsInstance *arguments, unsigned idx)
{
    if(arguments->buf)
        return arguments->buf + idx;
    if(arguments->frame->base_scope->frame || idx >= arguments->frame->function->param_cnt)
        return arguments->jsdisp.ctx->stack + arguments->frame->arguments_off + idx;
    return NULL;
}

static HRESULT Arguments_idx_get(jsdisp_t *jsdisp, unsigned idx, jsval_t *r)
{
    ArgumentsInstance *arguments = arguments_from_jsdisp(jsdisp);
    jsval_t *ref;

    TRACE("%p[%u]\n", arguments, idx);

    if((ref = get_argument_ref(arguments, idx)))
        return jsval_copy(*ref, r);

    /* FIXME: Accessing by name won't work for duplicated argument names */
    return jsdisp_propget_name(arguments->frame->base_scope->jsobj, arguments->function->func_code->params[idx], r);
}

static HRESULT Arguments_idx_put(jsdisp_t *jsdisp, unsigned idx, jsval_t val)
{
    ArgumentsInstance *arguments = arguments_from_jsdisp(jsdisp);
    jsval_t *ref;
    HRESULT hres;

    TRACE("%p[%u] = %s\n", arguments, idx, debugstr_jsval(val));

    if((ref = get_argument_ref(arguments, idx))) {
        jsval_t copy;
        hres = jsval_copy(val, &copy);
        if(FAILED(hres))
            return hres;

        jsval_release(*ref);
        *ref = copy;
        return S_OK;
    }

    /* FIXME: Accessing by name won't work for duplicated argument names */
    return jsdisp_propput_name(arguments->frame->base_scope->jsobj, arguments->function->func_code->params[idx], val);
}

static const builtin_info_t Arguments_info = {
    JSCLASS_ARGUMENTS,
    {NULL, Arguments_value, 0},
    0, NULL,
    Arguments_destructor,
    NULL,
    Arguments_idx_length,
    Arguments_idx_get,
    Arguments_idx_put
};

HRESULT setup_arguments_object(script_ctx_t *ctx, call_frame_t *frame)
{
    ArgumentsInstance *args;
    HRESULT hres;

    static const WCHAR caleeW[] = {'c','a','l','l','e','e',0};

    args = heap_alloc_zero(sizeof(*args));
    if(!args)
        return E_OUTOFMEMORY;

    hres = init_dispex_from_constr(&args->jsdisp, ctx, &Arguments_info, ctx->object_constr);
    if(FAILED(hres)) {
        heap_free(args);
        return hres;
    }

    args->function = function_from_jsdisp(jsdisp_addref(frame->function_instance));
    args->argc = frame->argc;
    args->frame = frame;

    hres = jsdisp_define_data_property(&args->jsdisp, lengthW, PROPF_WRITABLE | PROPF_CONFIGURABLE,
                                       jsval_number(args->argc));
    if(SUCCEEDED(hres))
        hres = jsdisp_define_data_property(&args->jsdisp, caleeW, PROPF_WRITABLE | PROPF_CONFIGURABLE,
                                           jsval_obj(&args->function->dispex));
    if(SUCCEEDED(hres))
        hres = jsdisp_propput(frame->base_scope->jsobj, argumentsW, PROPF_WRITABLE, jsval_obj(&args->jsdisp));
    if(FAILED(hres)) {
        jsdisp_release(&args->jsdisp);
        return hres;
    }

    frame->arguments_obj = &args->jsdisp;
    return S_OK;
}

void detach_arguments_object(jsdisp_t *args_disp)
{
    ArgumentsInstance *arguments = arguments_from_jsdisp(args_disp);
    call_frame_t *frame = arguments->frame;
    const BOOL on_stack = frame->base_scope->frame == frame;
    HRESULT hres;

    /* Reset arguments value to cut the reference cycle. Note that since all activation contexts have
     * their own arguments property, it's impossible to use prototype's one during name lookup */
    jsdisp_propput_name(frame->base_scope->jsobj, argumentsW, jsval_undefined());
    arguments->frame = NULL;

    /* Don't bother coppying arguments if call frame holds the last reference. */
    if(arguments->jsdisp.ref > 1) {
        arguments->buf = heap_alloc(arguments->argc * sizeof(*arguments->buf));
        if(arguments->buf) {
            int i;

            for(i = 0; i < arguments->argc ; i++) {
                if(on_stack || i >= frame->function->param_cnt)
                    hres = jsval_copy(arguments->jsdisp.ctx->stack[frame->arguments_off + i], arguments->buf+i);
                else
                    hres = jsdisp_propget_name(frame->base_scope->jsobj, frame->function->params[i], arguments->buf+i);
                if(FAILED(hres))
                    arguments->buf[i] = jsval_undefined();
            }
        }else {
            ERR("out of memory\n");
            arguments->argc = 0;
        }
    }

    jsdisp_release(frame->arguments_obj);
}

static HRESULT invoke_source(script_ctx_t *ctx, FunctionInstance *function, IDispatch *this_obj, unsigned argc, jsval_t *argv,
        BOOL is_constructor, BOOL caller_execs_source, jsval_t *r)
{
    jsdisp_t *var_disp;
    DWORD exec_flags = 0;
    HRESULT hres;

    if(ctx->state == SCRIPTSTATE_UNINITIALIZED || ctx->state == SCRIPTSTATE_CLOSED) {
        WARN("Script engine state does not allow running code.\n");
        return E_UNEXPECTED;
    }

    if(!function->func_code) {
        FIXME("no source\n");
        return E_FAIL;
    }

    hres = create_dispex(ctx, NULL, NULL, &var_disp);
    if(FAILED(hres))
        return hres;

    if(caller_execs_source)
        exec_flags |= EXEC_RETURN_TO_INTERP;
    if(is_constructor)
        exec_flags |= EXEC_CONSTRUCTOR;
    hres = exec_source(ctx, exec_flags, function->code, function->func_code, function->scope_chain, this_obj,
            &function->dispex, var_disp, argc, argv, r);

    jsdisp_release(var_disp);
    return hres;
}

static HRESULT invoke_value_proc(script_ctx_t *ctx, FunctionInstance *function, IDispatch *this_disp, WORD flags,
        unsigned argc, jsval_t *argv, jsval_t *r)
{
    vdisp_t vthis;
    HRESULT hres;

    if(this_disp)
        set_disp(&vthis, this_disp);
    else if(ctx->host_global)
        set_disp(&vthis, ctx->host_global);
    else
        set_jsdisp(&vthis, ctx->global);

    hres = function->value_proc(ctx, &vthis, flags, argc, argv, r);

    vdisp_release(&vthis);
    return hres;
}

static HRESULT call_function(script_ctx_t *ctx, FunctionInstance *function, IDispatch *this_obj,
        unsigned argc, jsval_t *argv, BOOL caller_execs_source, jsval_t *r)
{
    if(function->value_proc)
        return invoke_value_proc(ctx, function, this_obj, DISPATCH_METHOD, argc, argv, r);

    return invoke_source(ctx, function, this_obj, argc, argv, FALSE, caller_execs_source, r);
}

static HRESULT function_to_string(FunctionInstance *function, jsstr_t **ret)
{
    jsstr_t *str;

    static const WCHAR native_prefixW[] = {'\n','f','u','n','c','t','i','o','n',' '};
    static const WCHAR native_suffixW[] =
        {'(',')',' ','{','\n',' ',' ',' ',' ','[','n','a','t','i','v','e',' ','c','o','d','e',']','\n','}','\n'};

    if(function->value_proc) {
        DWORD name_len;
        WCHAR *ptr;

        name_len = lstrlenW(function->name);
        str = jsstr_alloc_buf(ARRAY_SIZE(native_prefixW) + ARRAY_SIZE(native_suffixW) + name_len, &ptr);
        if(!str)
            return E_OUTOFMEMORY;

        memcpy(ptr, native_prefixW, sizeof(native_prefixW));
        memcpy(ptr += ARRAY_SIZE(native_prefixW), function->name, name_len*sizeof(WCHAR));
        memcpy(ptr + name_len, native_suffixW, sizeof(native_suffixW));
    }else {
        str = jsstr_alloc_len(function->func_code->source, function->func_code->source_len);
        if(!str)
            return E_OUTOFMEMORY;
    }

    *ret = str;
    return S_OK;
}

HRESULT Function_invoke(jsdisp_t *func_this, IDispatch *jsthis, WORD flags, unsigned argc, jsval_t *argv, jsval_t *r)
{
    const BOOL caller_execs_source = (flags & DISPATCH_JSCRIPT_CALLEREXECSSOURCE) != 0;
    FunctionInstance *function;

    TRACE("func %p this %p\n", func_this, jsthis);

    assert(is_class(func_this, JSCLASS_FUNCTION));
    function = function_from_jsdisp(func_this);

    flags &= ~DISPATCH_JSCRIPT_INTERNAL_MASK;
    if(function->value_proc)
        return invoke_value_proc(function->dispex.ctx, function, jsthis, flags, argc, argv, r);

    if(flags == DISPATCH_CONSTRUCT) {
        jsdisp_t *this_obj;
        HRESULT hres;

        hres = create_object(function->dispex.ctx, &function->dispex, &this_obj);
        if(FAILED(hres))
            return hres;

        hres = invoke_source(function->dispex.ctx, function, to_disp(this_obj), argc, argv, TRUE, caller_execs_source, r);
        jsdisp_release(this_obj);
        return hres;
    }

    assert(flags == DISPATCH_METHOD);
    return invoke_source(function->dispex.ctx, function, jsthis, argc, argv, FALSE, caller_execs_source, r);
}

static HRESULT Function_get_length(script_ctx_t *ctx, jsdisp_t *jsthis, jsval_t *r)
{
    TRACE("%p\n", jsthis);

    *r = jsval_number(function_from_jsdisp(jsthis)->length);
    return S_OK;
}

static HRESULT Function_toString(script_ctx_t *ctx, vdisp_t *jsthis, WORD flags, unsigned argc, jsval_t *argv,
        jsval_t *r)
{
    FunctionInstance *function;
    jsstr_t *str;
    HRESULT hres;

    TRACE("\n");

    if(!(function = function_this(jsthis)))
        return throw_type_error(ctx, JS_E_FUNCTION_EXPECTED, NULL);

    hres = function_to_string(function, &str);
    if(FAILED(hres))
        return hres;

    if(r)
        *r = jsval_string(str);
    else
        jsstr_release(str);
    return S_OK;
}

static HRESULT array_to_args(script_ctx_t *ctx, jsdisp_t *arg_array, unsigned *argc, jsval_t **ret)
{
    jsval_t *argv, val;
    DWORD length, i;
    HRESULT hres;

    hres = jsdisp_propget_name(arg_array, lengthW, &val);
    if(FAILED(hres))
        return hres;

    hres = to_uint32(ctx, val, &length);
    jsval_release(val);
    if(FAILED(hres))
        return hres;

    argv = heap_alloc(length * sizeof(*argv));
    if(!argv)
        return E_OUTOFMEMORY;

    for(i=0; i<length; i++) {
        hres = jsdisp_get_idx(arg_array, i, argv+i);
        if(hres == DISP_E_UNKNOWNNAME) {
            argv[i] = jsval_undefined();
        }else if(FAILED(hres)) {
            while(i--)
                jsval_release(argv[i]);
            heap_free(argv);
            return hres;
        }
    }

    *argc = length;
    *ret = argv;
    return S_OK;
}

static HRESULT Function_apply(script_ctx_t *ctx, vdisp_t *jsthis, WORD flags, unsigned argc, jsval_t *argv, jsval_t *r)
{
    FunctionInstance *function;
    jsval_t *args = NULL;
    unsigned i, cnt = 0;
    IDispatch *this_obj = NULL;
    HRESULT hres = S_OK;

    TRACE("\n");

    if(!(function = function_this(jsthis)) && (jsthis->flags & VDISP_JSDISP))
        return throw_type_error(ctx, JS_E_FUNCTION_EXPECTED, NULL);

    if(argc) {
        if(!is_undefined(argv[0]) && !is_null(argv[0])) {
            hres = to_object(ctx, argv[0], &this_obj);
            if(FAILED(hres))
                return hres;
        }
    }

    if(argc >= 2) {
        jsdisp_t *arg_array = NULL;

        if(is_object_instance(argv[1])) {
            arg_array = iface_to_jsdisp(get_object(argv[1]));
            if(arg_array &&
               (!is_class(arg_array, JSCLASS_ARRAY) && !is_class(arg_array, JSCLASS_ARGUMENTS) )) {
                jsdisp_release(arg_array);
                arg_array = NULL;
            }
        }

        if(arg_array) {
            hres = array_to_args(ctx, arg_array, &cnt, &args);
            jsdisp_release(arg_array);
        }else {
            FIXME("throw TypeError\n");
            hres = E_FAIL;
        }
    }

    if(SUCCEEDED(hres)) {
        if(function) {
            hres = call_function(ctx, function, this_obj, cnt, args, (flags & DISPATCH_JSCRIPT_CALLEREXECSSOURCE) != 0, r);
        }else {
            jsval_t res;
            hres = disp_call_value(ctx, jsthis->u.disp, this_obj, DISPATCH_METHOD, cnt, args, &res);
            if(SUCCEEDED(hres)) {
                if(r)
                    *r = res;
                else
                    jsval_release(res);
            }
        }
    }

    if(this_obj)
        IDispatch_Release(this_obj);
    for(i=0; i < cnt; i++)
        jsval_release(args[i]);
    heap_free(args);
    return hres;
}

static HRESULT Function_call(script_ctx_t *ctx, vdisp_t *jsthis, WORD flags, unsigned argc, jsval_t *argv,
        jsval_t *r)
{
    FunctionInstance *function;
    IDispatch *this_obj = NULL;
    unsigned cnt = 0;
    HRESULT hres;

    TRACE("\n");

    if(!(function = function_this(jsthis)))
        return throw_type_error(ctx, JS_E_FUNCTION_EXPECTED, NULL);

    if(argc) {
        if(!is_undefined(argv[0]) && !is_null(argv[0])) {
            hres = to_object(ctx, argv[0], &this_obj);
            if(FAILED(hres))
                return hres;
        }

        cnt = argc-1;
    }

    hres = call_function(ctx, function, this_obj, cnt, argv+1, (flags & DISPATCH_JSCRIPT_CALLEREXECSSOURCE) != 0, r);

    if(this_obj)
        IDispatch_Release(this_obj);
    return hres;
}

HRESULT Function_value(script_ctx_t *ctx, vdisp_t *jsthis, WORD flags, unsigned argc, jsval_t *argv,
        jsval_t *r)
{
    FunctionInstance *function;

    TRACE("\n");

    if(!is_vclass(jsthis, JSCLASS_FUNCTION)) {
        ERR("dispex is not a function\n");
        return E_FAIL;
    }

    function = function_from_jsdisp(jsthis->u.jsdisp);

    assert(function->value_proc != NULL);
    return invoke_value_proc(ctx, function, NULL, flags, argc, argv, r);
}

HRESULT Function_get_value(script_ctx_t *ctx, jsdisp_t *jsthis, jsval_t *r)
{
    jsstr_t *str;
    HRESULT hres;

    TRACE("\n");

    hres = function_to_string(function_from_jsdisp(jsthis), &str);
    if(FAILED(hres))
        return hres;

    *r = jsval_string(str);
    return S_OK;
}

static HRESULT Function_get_arguments(script_ctx_t *ctx, jsdisp_t *jsthis, jsval_t *r)
{
    FunctionInstance *function = function_from_jsdisp(jsthis);
    call_frame_t *frame;
    HRESULT hres;

    TRACE("\n");

    for(frame = ctx->call_ctx; frame; frame = frame->prev_frame) {
        if(frame->function_instance == &function->dispex) {
            if(!frame->arguments_obj) {
                hres = setup_arguments_object(ctx, frame);
                if(FAILED(hres))
                    return hres;
            }
            *r = jsval_obj(jsdisp_addref(frame->arguments_obj));
            return S_OK;
        }
    }

    *r = jsval_null();
    return S_OK;
}

static void Function_destructor(jsdisp_t *dispex)
{
    FunctionInstance *This = function_from_jsdisp(dispex);

    if(This->code)
        release_bytecode(This->code);
    if(This->scope_chain)
        scope_release(This->scope_chain);
    heap_free(This);
}

static const builtin_prop_t Function_props[] = {
    {applyW,                 Function_apply,                 PROPF_METHOD|2},
    {argumentsW,             NULL, 0,                        Function_get_arguments},
    {callW,                  Function_call,                  PROPF_METHOD|1},
    {lengthW,                NULL, 0,                        Function_get_length},
    {toStringW,              Function_toString,              PROPF_METHOD}
};

static const builtin_info_t Function_info = {
    JSCLASS_FUNCTION,
    DEFAULT_FUNCTION_VALUE,
    ARRAY_SIZE(Function_props),
    Function_props,
    Function_destructor,
    NULL
};

static const builtin_prop_t FunctionInst_props[] = {
    {argumentsW,             NULL, 0,                        Function_get_arguments},
    {lengthW,                NULL, 0,                        Function_get_length}
};

static const builtin_info_t FunctionInst_info = {
    JSCLASS_FUNCTION,
    DEFAULT_FUNCTION_VALUE,
    ARRAY_SIZE(FunctionInst_props),
    FunctionInst_props,
    Function_destructor,
    NULL
};

static HRESULT create_function(script_ctx_t *ctx, const builtin_info_t *builtin_info, DWORD flags,
        BOOL funcprot, jsdisp_t *prototype, FunctionInstance **ret)
{
    FunctionInstance *function;
    HRESULT hres;

    function = heap_alloc_zero(sizeof(FunctionInstance));
    if(!function)
        return E_OUTOFMEMORY;

    if(funcprot)
        hres = init_dispex(&function->dispex, ctx, builtin_info, prototype);
    else if(builtin_info)
        hres = init_dispex_from_constr(&function->dispex, ctx, builtin_info, ctx->function_constr);
    else
        hres = init_dispex_from_constr(&function->dispex, ctx, &FunctionInst_info, ctx->function_constr);
    if(FAILED(hres)) {
        heap_free(function);
        return hres;
    }

    function->flags = flags;
    function->length = flags & PROPF_ARGMASK;

    *ret = function;
    return S_OK;
}

HRESULT create_builtin_function(script_ctx_t *ctx, builtin_invoke_t value_proc, const WCHAR *name,
        const builtin_info_t *builtin_info, DWORD flags, jsdisp_t *prototype, jsdisp_t **ret)
{
    FunctionInstance *function;
    HRESULT hres;

    hres = create_function(ctx, builtin_info, flags, FALSE, NULL, &function);
    if(FAILED(hres))
        return hres;

    if(builtin_info)
        hres = jsdisp_define_data_property(&function->dispex, lengthW, 0,
                                           jsval_number(function->length));
    if(SUCCEEDED(hres))
        hres = jsdisp_define_data_property(&function->dispex, prototypeW, 0, jsval_obj(prototype));
    if(FAILED(hres)) {
        jsdisp_release(&function->dispex);
        return hres;
    }

    function->value_proc = value_proc;
    function->name = name;

    *ret = &function->dispex;
    return S_OK;
}

static HRESULT set_constructor_prop(script_ctx_t *ctx, jsdisp_t *constr, jsdisp_t *prot)
{
    static const WCHAR constructorW[] = {'c','o','n','s','t','r','u','c','t','o','r',0};

    return jsdisp_define_data_property(prot, constructorW, PROPF_WRITABLE | PROPF_CONFIGURABLE,
                                       jsval_obj(constr));
}

HRESULT create_builtin_constructor(script_ctx_t *ctx, builtin_invoke_t value_proc, const WCHAR *name,
        const builtin_info_t *builtin_info, DWORD flags, jsdisp_t *prototype, jsdisp_t **ret)
{
    jsdisp_t *constr;
    HRESULT hres;

    hres = create_builtin_function(ctx, value_proc, name, builtin_info, flags, prototype, &constr);
    if(FAILED(hres))
        return hres;

    hres = set_constructor_prop(ctx, constr, prototype);
    if(FAILED(hres)) {
        jsdisp_release(constr);
        return hres;
    }

    *ret = constr;
    return S_OK;
}

HRESULT create_source_function(script_ctx_t *ctx, bytecode_t *code, function_code_t *func_code,
        scope_chain_t *scope_chain, jsdisp_t **ret)
{
    FunctionInstance *function;
    jsdisp_t *prototype;
    HRESULT hres;

    hres = create_object(ctx, NULL, &prototype);
    if(FAILED(hres))
        return hres;

    hres = create_function(ctx, NULL, PROPF_CONSTR, FALSE, NULL, &function);
    if(SUCCEEDED(hres)) {
        hres = jsdisp_define_data_property(&function->dispex, prototypeW, PROPF_WRITABLE,
                                           jsval_obj(prototype));
        if(SUCCEEDED(hres))
            hres = set_constructor_prop(ctx, &function->dispex, prototype);
        if(FAILED(hres))
            jsdisp_release(&function->dispex);
    }
    jsdisp_release(prototype);
    if(FAILED(hres))
        return hres;

    if(scope_chain) {
        scope_addref(scope_chain);
        function->scope_chain = scope_chain;
    }

    bytecode_addref(code);
    function->code = code;
    function->func_code = func_code;
    function->length = function->func_code->param_cnt;

    *ret = &function->dispex;
    return S_OK;
}

static HRESULT construct_function(script_ctx_t *ctx, unsigned argc, jsval_t *argv, IDispatch **ret)
{
    WCHAR *str = NULL, *ptr;
    unsigned len = 0, i = 0;
    bytecode_t *code;
    jsdisp_t *function;
    jsstr_t **params = NULL;
    int j = 0;
    HRESULT hres = S_OK;

    static const WCHAR function_anonymousW[] = {'f','u','n','c','t','i','o','n',' ','a','n','o','n','y','m','o','u','s','('};
    static const WCHAR function_beginW[] = {')',' ','{','\n'};
    static const WCHAR function_endW[] = {'\n','}',0};

    if(argc) {
        params = heap_alloc(argc*sizeof(*params));
        if(!params)
            return E_OUTOFMEMORY;

        if(argc > 2)
            len = (argc-2)*2; /* separating commas */
        for(i=0; i < argc; i++) {
            hres = to_string(ctx, argv[i], params+i);
            if(FAILED(hres))
                break;
            len += jsstr_length(params[i]);
        }
    }

    if(SUCCEEDED(hres)) {
        len += ARRAY_SIZE(function_anonymousW) + ARRAY_SIZE(function_beginW) + ARRAY_SIZE(function_endW);
        str = heap_alloc(len*sizeof(WCHAR));
        if(str) {
            memcpy(str, function_anonymousW, sizeof(function_anonymousW));
            ptr = str + ARRAY_SIZE(function_anonymousW);
            if(argc > 1) {
                while(1) {
                    ptr += jsstr_flush(params[j], ptr);
                    if(++j == argc-1)
                        break;
                    *ptr++ = ',';
                    *ptr++ = ' ';
                }
            }
            memcpy(ptr, function_beginW, sizeof(function_beginW));
            ptr += ARRAY_SIZE(function_beginW);
            if(argc)
                ptr += jsstr_flush(params[argc-1], ptr);
            memcpy(ptr, function_endW, sizeof(function_endW));

            TRACE("%s\n", debugstr_w(str));
        }else {
            hres = E_OUTOFMEMORY;
        }
    }

    while(i)
        jsstr_release(params[--i]);
    heap_free(params);
    if(FAILED(hres))
        return hres;

    hres = compile_script(ctx, str, NULL, NULL, FALSE, FALSE, &code);
    heap_free(str);
    if(FAILED(hres))
        return hres;

    if(code->global_code.func_cnt != 1 || code->global_code.var_cnt != 1) {
        ERR("Invalid parser result!\n");
        release_bytecode(code);
        return E_UNEXPECTED;
    }

    hres = create_source_function(ctx, code, code->global_code.funcs, NULL, &function);
    release_bytecode(code);
    if(FAILED(hres))
        return hres;

    *ret = to_disp(function);
    return S_OK;
}

static HRESULT FunctionConstr_value(script_ctx_t *ctx, vdisp_t *jsthis, WORD flags, unsigned argc, jsval_t *argv,
        jsval_t *r)
{
    HRESULT hres;

    TRACE("\n");

    switch(flags) {
    case DISPATCH_METHOD:
    case DISPATCH_CONSTRUCT: {
        IDispatch *ret;

        hres = construct_function(ctx, argc, argv, &ret);
        if(FAILED(hres))
            return hres;

        *r = jsval_disp(ret);
        break;
    }
    default:
        FIXME("unimplemented flags %x\n", flags);
        return E_NOTIMPL;
    }

    return S_OK;
}

static HRESULT FunctionProt_value(script_ctx_t *ctx, vdisp_t *jsthis, WORD flags, unsigned argc, jsval_t *argv,
        jsval_t *r)
{
    FIXME("\n");
    return E_NOTIMPL;
}

HRESULT init_function_constr(script_ctx_t *ctx, jsdisp_t *object_prototype)
{
    FunctionInstance *prot, *constr;
    HRESULT hres;

    static const WCHAR FunctionW[] = {'F','u','n','c','t','i','o','n',0};

    hres = create_function(ctx, &Function_info, PROPF_CONSTR, TRUE, object_prototype, &prot);
    if(FAILED(hres))
        return hres;

    prot->value_proc = FunctionProt_value;
    prot->name = prototypeW;

    hres = create_function(ctx, &FunctionInst_info, PROPF_CONSTR|1, TRUE, &prot->dispex, &constr);
    if(SUCCEEDED(hres)) {
        constr->value_proc = FunctionConstr_value;
        constr->name = FunctionW;
        hres = jsdisp_define_data_property(&constr->dispex, prototypeW, 0, jsval_obj(&prot->dispex));
        if(SUCCEEDED(hres))
            hres = set_constructor_prop(ctx, &constr->dispex, &prot->dispex);
        if(FAILED(hres))
            jsdisp_release(&constr->dispex);
    }
    jsdisp_release(&prot->dispex);
    if(FAILED(hres))
        return hres;

    ctx->function_constr = &constr->dispex;
    return S_OK;
}