jsiter.c

java script test programing source code

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sw=4 et tw=78:
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla Communicator client code, released
 * March 31, 1998.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

/*
 * JavaScript iterators.
 */
#include "jsstddef.h"
#include <string.h>     /* for memcpy */
#include "jstypes.h"
#include "jsutil.h"
#include "jsarena.h"
#include "jsapi.h"
#include "jsarray.h"
#include "jsatom.h"
#include "jsbool.h"
#include "jscntxt.h"
#include "jsconfig.h"
#include "jsexn.h"
#include "jsfun.h"
#include "jsgc.h"
#include "jsinterp.h"
#include "jsiter.h"
#include "jslock.h"
#include "jsnum.h"
#include "jsobj.h"
#include "jsopcode.h"
#include "jsscope.h"
#include "jsscript.h"

#if JS_HAS_XML_SUPPORT
#include "jsxml.h"
#endif

extern const char js_throw_str[]; /* from jsscan.h */

#define JSSLOT_ITER_STATE       (JSSLOT_PRIVATE)
#define JSSLOT_ITER_FLAGS       (JSSLOT_PRIVATE + 1)

#if JSSLOT_ITER_FLAGS >= JS_INITIAL_NSLOTS
#error JS_INITIAL_NSLOTS must be greater than JSSLOT_ITER_FLAGS.
#endif

/*
 * Shared code to close iterator's state either through an explicit call or
 * when GC detects that the iterator is no longer reachable.
 */
void
js_CloseIteratorState(JSContext *cx, JSObject *iterobj)
{
    jsval *slots;
    jsval state, parent;
    JSObject *iterable;

    JS_ASSERT(JS_InstanceOf(cx, iterobj, &js_IteratorClass, NULL));
    slots = iterobj->slots;

    /* Avoid double work if js_CloseNativeIterator was called on obj. */
    state = slots[JSSLOT_ITER_STATE];
    if (JSVAL_IS_NULL(state))
        return;

    /* Protect against failure to fully initialize obj. */
    parent = slots[JSSLOT_PARENT];
    if (!JSVAL_IS_PRIMITIVE(parent)) {
        iterable = JSVAL_TO_OBJECT(parent);
#if JS_HAS_XML_SUPPORT
        if ((JSVAL_TO_INT(slots[JSSLOT_ITER_FLAGS]) & JSITER_FOREACH) &&
            OBJECT_IS_XML(cx, iterable)) {
            ((JSXMLObjectOps *) iterable->map->ops)->
                enumerateValues(cx, iterable, JSENUMERATE_DESTROY, &state,
                                NULL, NULL);
        } else
#endif
            OBJ_ENUMERATE(cx, iterable, JSENUMERATE_DESTROY, &state, NULL);
    }
    slots[JSSLOT_ITER_STATE] = JSVAL_NULL;
}

JSClass js_IteratorClass = {
    "Iterator",
    JSCLASS_HAS_RESERVED_SLOTS(2) | /* slots for state and flags */
    JSCLASS_HAS_CACHED_PROTO(JSProto_Iterator),
    JS_PropertyStub,  JS_PropertyStub,  JS_PropertyStub,  JS_PropertyStub,
    JS_EnumerateStub, JS_ResolveStub,   JS_ConvertStub,   JS_FinalizeStub,
    JSCLASS_NO_OPTIONAL_MEMBERS
};

static JSBool
InitNativeIterator(JSContext *cx, JSObject *iterobj, JSObject *obj, uintN flags)
{
    jsval state;
    JSBool ok;

    JS_ASSERT(JSVAL_TO_PRIVATE(iterobj->slots[JSSLOT_CLASS]) ==
              &js_IteratorClass);

    /* Initialize iterobj in case of enumerate hook failure. */
    iterobj->slots[JSSLOT_PARENT] = OBJECT_TO_JSVAL(obj);
    iterobj->slots[JSSLOT_ITER_STATE] = JSVAL_NULL;
    iterobj->slots[JSSLOT_ITER_FLAGS] = INT_TO_JSVAL(flags);
    if (!js_RegisterCloseableIterator(cx, iterobj))
        return JS_FALSE;
    if (!obj)
        return JS_TRUE;

    ok =
#if JS_HAS_XML_SUPPORT
         ((flags & JSITER_FOREACH) && OBJECT_IS_XML(cx, obj))
         ? ((JSXMLObjectOps *) obj->map->ops)->
               enumerateValues(cx, obj, JSENUMERATE_INIT, &state, NULL, NULL)
         :
#endif
           OBJ_ENUMERATE(cx, obj, JSENUMERATE_INIT, &state, NULL);
    if (!ok)
        return JS_FALSE;

    iterobj->slots[JSSLOT_ITER_STATE] = state;
    if (flags & JSITER_ENUMERATE) {
        /*
         * The enumerating iterator needs the original object to suppress
         * enumeration of deleted or shadowed prototype properties. Since the
         * enumerator never escapes to scripts, we use the prototype slot to
         * store the original object.
         */
        JS_ASSERT(obj != iterobj);
        iterobj->slots[JSSLOT_PROTO] = OBJECT_TO_JSVAL(obj);
    }
    return JS_TRUE;
}

static JSBool
Iterator(JSContext *cx, JSObject *iterobj, uintN argc, jsval *argv, jsval *rval)
{
    JSBool keyonly;
    uintN flags;
    JSObject *obj;

    keyonly = JS_FALSE;
    if (!js_ValueToBoolean(cx, argv[1], &keyonly))
        return JS_FALSE;
    flags = keyonly ? 0 : JSITER_FOREACH;

    if (cx->fp->flags & JSFRAME_CONSTRUCTING) {
        /* XXX work around old valueOf call hidden beneath js_ValueToObject */
        if (!JSVAL_IS_PRIMITIVE(argv[0])) {
            obj = JSVAL_TO_OBJECT(argv[0]);
        } else {
            obj = js_ValueToNonNullObject(cx, argv[0]);
            if (!obj)
                return JS_FALSE;
            argv[0] = OBJECT_TO_JSVAL(obj);
        }
        return InitNativeIterator(cx, iterobj, obj, flags);
    }

    *rval = argv[0];
    return js_ValueToIterator(cx, flags, rval);
}

static JSBool
NewKeyValuePair(JSContext *cx, jsid key, jsval val, jsval *rval)
{
    jsval vec[2];
    JSTempValueRooter tvr;
    JSObject *aobj;

    vec[0] = ID_TO_VALUE(key);
    vec[1] = val;

    JS_PUSH_TEMP_ROOT(cx, 2, vec, &tvr);
    aobj = js_NewArrayObject(cx, 2, vec);
    *rval = OBJECT_TO_JSVAL(aobj);
    JS_POP_TEMP_ROOT(cx, &tvr);

    return aobj != NULL;
}

static JSBool
IteratorNextImpl(JSContext *cx, JSObject *obj, jsval *rval)
{
    JSObject *iterable;
    jsval state;
    uintN flags;
    JSBool foreach, ok;
    jsid id;

    JS_ASSERT(OBJ_GET_CLASS(cx, obj) == &js_IteratorClass);

    iterable = OBJ_GET_PARENT(cx, obj);
    JS_ASSERT(iterable);
    state = OBJ_GET_SLOT(cx, obj, JSSLOT_ITER_STATE);
    if (JSVAL_IS_NULL(state))
        goto stop;

    flags = JSVAL_TO_INT(OBJ_GET_SLOT(cx, obj, JSSLOT_ITER_FLAGS));
    JS_ASSERT(!(flags & JSITER_ENUMERATE));
    foreach = (flags & JSITER_FOREACH) != 0;
    ok =
#if JS_HAS_XML_SUPPORT
         (foreach && OBJECT_IS_XML(cx, iterable))
         ? ((JSXMLObjectOps *) iterable->map->ops)->
               enumerateValues(cx, iterable, JSENUMERATE_NEXT, &state,
                               &id, rval)
         :
#endif
           OBJ_ENUMERATE(cx, iterable, JSENUMERATE_NEXT, &state, &id);
    if (!ok)
        return JS_FALSE;

    OBJ_SET_SLOT(cx, obj, JSSLOT_ITER_STATE, state);
    if (JSVAL_IS_NULL(state))
        goto stop;

    if (foreach) {
#if JS_HAS_XML_SUPPORT
        if (!OBJECT_IS_XML(cx, iterable) &&
            !OBJ_GET_PROPERTY(cx, iterable, id, rval)) {
            return JS_FALSE;
        }
#endif
        if (!NewKeyValuePair(cx, id, *rval, rval))
            return JS_FALSE;
    } else {
        *rval = ID_TO_VALUE(id);
    }
    return JS_TRUE;

  stop:
    JS_ASSERT(OBJ_GET_SLOT(cx, obj, JSSLOT_ITER_STATE) == JSVAL_NULL);
    *rval = JSVAL_HOLE;
    return JS_TRUE;
}

static JSBool
js_ThrowStopIteration(JSContext *cx, JSObject *obj)
{
    jsval v;

    JS_ASSERT(!JS_IsExceptionPending(cx));
    if (js_FindClassObject(cx, NULL, INT_TO_JSID(JSProto_StopIteration), &v))
        JS_SetPendingException(cx, v);
    return JS_FALSE;
}

static JSBool
iterator_next(JSContext *cx, JSObject *obj, uintN argc, jsval *argv,
              jsval *rval)
{
    if (!JS_InstanceOf(cx, obj, &js_IteratorClass, argv))
        return JS_FALSE;

    if (!IteratorNextImpl(cx, obj, rval))
        return JS_FALSE;

    if (*rval == JSVAL_HOLE) {
        *rval = JSVAL_NULL;
        js_ThrowStopIteration(cx, obj);
        return JS_FALSE;
    }
    return JS_TRUE;
}

static JSBool
iterator_self(JSContext *cx, JSObject *obj, uintN argc, jsval *argv,
              jsval *rval)
{
    *rval = OBJECT_TO_JSVAL(obj);
    return JS_TRUE;
}

static JSFunctionSpec iterator_methods[] = {
    {js_iterator_str, iterator_self, 0,JSPROP_READONLY|JSPROP_PERMANENT,0},
    {js_next_str,     iterator_next, 0,JSPROP_READONLY|JSPROP_PERMANENT,0},
    {0,0,0,0,0}
};

uintN
js_GetNativeIteratorFlags(JSContext *cx, JSObject *iterobj)
{
    if (OBJ_GET_CLASS(cx, iterobj) != &js_IteratorClass)
        return 0;
    return JSVAL_TO_INT(OBJ_GET_SLOT(cx, iterobj, JSSLOT_ITER_FLAGS));
}

void
js_CloseNativeIterator(JSContext *cx, JSObject *iterobj)
{
    uintN flags;

    /*
     * If this iterator is not an instance of the native default iterator
     * class, leave it to be GC'ed.
     */
    if (!JS_InstanceOf(cx, iterobj, &js_IteratorClass, NULL))
        return;

    /*
     * If this iterator was not created by js_ValueToIterator called from the
     * for-in loop code in js_Interpret, leave it to be GC'ed.
     */
    flags = JSVAL_TO_INT(OBJ_GET_SLOT(cx, iterobj, JSSLOT_ITER_FLAGS));
    if (!(flags & JSITER_ENUMERATE))
        return;

    js_CloseIteratorState(cx, iterobj);
}

/*
 * Call ToObject(v).__iterator__(keyonly) if ToObject(v).__iterator__ exists.
 * Otherwise construct the defualt iterator.
 */
JSBool
js_ValueToIterator(JSContext *cx, uintN flags, jsval *vp)
{
    JSObject *obj;
    JSTempValueRooter tvr;
    const JSAtom *atom;
    JSBool ok;
    JSObject *iterobj;
    jsval arg;
    JSString *str;

    JS_ASSERT(!(flags & ~(JSITER_ENUMERATE |
                          JSITER_FOREACH |