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gecko/js/src/jsiter.cpp
Igor Bukanov 02fc618d59 bug 566836 - eliminating JSObjectOps::dropProperty. r=gal 
--HG--
extra : rebase_source : cdffca0a863d8a3dddbc77335fc3cdac2eff9f4b
2010-06-05 23:24:54 +02:00

1286 lines
40 KiB
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/* -*- 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 <string.h> /* for memcpy */
#include "jstypes.h"
#include "jsstdint.h"
#include "jsutil.h"
#include "jsarena.h"
#include "jsapi.h"
#include "jsarray.h"
#include "jsatom.h"
#include "jsbool.h"
#include "jsbuiltins.h"
#include "jscntxt.h"
#include "jsversion.h"
#include "jsexn.h"
#include "jsfun.h"
#include "jsgc.h"
#include "jshashtable.h"
#include "jsinterp.h"
#include "jsiter.h"
#include "jslock.h"
#include "jsnum.h"
#include "jsobj.h"
#include "jsopcode.h"
#include "jsproxy.h"
#include "jsscan.h"
#include "jsscope.h"
#include "jsscript.h"
#include "jsstaticcheck.h"
#include "jstracer.h"
#include "jsvector.h"
#if JS_HAS_XML_SUPPORT
#include "jsxml.h"
#endif
#include "jscntxtinlines.h"
#include "jsobjinlines.h"
#include "jsstrinlines.h"
using namespace js;
static void iterator_finalize(JSContext *cx, JSObject *obj);
static void iterator_trace(JSTracer *trc, JSObject *obj);
static JSObject *iterator_iterator(JSContext *cx, JSObject *obj, JSBool keysonly);
JSExtendedClass js_IteratorClass = {
{ "Iterator",
JSCLASS_HAS_PRIVATE |
JSCLASS_HAS_CACHED_PROTO(JSProto_Iterator) |
JSCLASS_MARK_IS_TRACE |
JSCLASS_IS_EXTENDED,
JS_PropertyStub, JS_PropertyStub, JS_PropertyStub, JS_PropertyStub,
JS_EnumerateStub, JS_ResolveStub, JS_ConvertStub, iterator_finalize,
NULL, NULL, NULL, NULL,
NULL, NULL, JS_CLASS_TRACE(iterator_trace), NULL },
NULL, NULL, NULL, iterator_iterator,
NULL,
JSCLASS_NO_RESERVED_MEMBERS
};
void
NativeIterator::mark(JSTracer *trc)
{
for (jsval *vp = props_array; vp < props_end; ++vp) {
JS_SET_TRACING_INDEX(trc, "props", (vp - props_array));
js_CallValueTracerIfGCThing(trc, *vp);
}
JS_CALL_OBJECT_TRACER(trc, obj, "obj");
}
/*
* Shared code to close iterator's state either through an explicit call or
* when GC detects that the iterator is no longer reachable.
*/
static void
iterator_finalize(JSContext *cx, JSObject *obj)
{
JS_ASSERT(obj->getClass() == &js_IteratorClass.base);
/* Avoid double work if the iterator was closed by JSOP_ENDITER. */
NativeIterator *ni = obj->getNativeIterator();
if (ni) {
cx->free(ni);
obj->setNativeIterator(NULL);
}
}
static void
iterator_trace(JSTracer *trc, JSObject *obj)
{
NativeIterator *ni = obj->getNativeIterator();
if (ni)
ni->mark(trc);
}
static bool
NewKeyValuePair(JSContext *cx, jsid key, jsval val, jsval *rval)
{
jsval vec[2] = { ID_TO_VALUE(key), val };
AutoArrayRooter tvr(cx, JS_ARRAY_LENGTH(vec), vec);
JSObject *aobj = js_NewArrayObject(cx, 2, vec);
if (!aobj)
return false;
*rval = OBJECT_TO_JSVAL(aobj);
return true;
}
static inline bool
Enumerate(JSContext *cx, JSObject *obj, JSObject *pobj, jsid id,
bool enumerable, uintN flags, HashSet<jsid>& ht,
AutoValueVector& vec)
{
JS_ASSERT(JSVAL_IS_INT(id) || JSVAL_IS_STRING(id));
if (JS_LIKELY(!(flags & JSITER_OWNONLY))) {
HashSet<jsid>::AddPtr p = ht.lookupForAdd(id);
/* property already encountered, done. */
if (JS_UNLIKELY(!!p))
return true;
/* no need to add properties to the hash table at the end of the prototype chain */
if (pobj->getProto() && !ht.add(p, id))
return false;
}
if (enumerable || (flags & JSITER_HIDDEN)) {
if (!vec.append(ID_TO_VALUE(id)))
return false;
if (flags & JSITER_FOREACH) {
jsval *vp = vec.end() - 1;
/* Do the lookup on the original object instead of the prototype. */
if (!obj->getProperty(cx, id, vp))
return false;
if ((flags & JSITER_KEYVALUE) && !NewKeyValuePair(cx, id, *vp, vp))
return false;
}
}
return true;
}
static bool
EnumerateNativeProperties(JSContext *cx, JSObject *obj, JSObject *pobj, uintN flags,
HashSet<jsid> &ht, AutoValueVector& props)
{
AutoValueVector sprops(cx);
JS_LOCK_OBJ(cx, pobj);
/* Collect all unique properties from this object's scope. */
JSScope *scope = pobj->scope();
for (JSScopeProperty *sprop = scope->lastProperty(); sprop; sprop = sprop->parent) {
if (sprop->id != JSVAL_VOID &&
!sprop->isAlias() &&
!Enumerate(cx, obj, pobj, sprop->id, sprop->enumerable(), flags, ht, sprops)) {
return false;
}
}
while (sprops.length() > 0) {
if (!props.append(sprops.back()))
return false;
sprops.popBack();
}
JS_UNLOCK_SCOPE(cx, scope);
return true;
}
static bool
EnumerateDenseArrayProperties(JSContext *cx, JSObject *obj, JSObject *pobj, uintN flags,
HashSet<jsid> &ht, AutoValueVector& props)
{
size_t count = pobj->getDenseArrayCount();
if (count) {
size_t capacity = pobj->getDenseArrayCapacity();
jsval *vp = pobj->dslots;
for (size_t i = 0; i < capacity; ++i, ++vp) {
if (*vp != JSVAL_HOLE) {
/* Dense arrays never get so large that i would not fit into an integer id. */
if (!Enumerate(cx, obj, pobj, INT_TO_JSVAL(i), true, flags, ht, props))
return false;
}
}
}
return true;
}
NativeIterator *
NativeIterator::allocate(JSContext *cx, JSObject *obj, uintN flags, uint32 *sarray, uint32 slength,
uint32 key, jsval *parray, uint32 plength)
{
NativeIterator *ni = (NativeIterator *)
cx->malloc(sizeof(NativeIterator) + plength * sizeof(jsval) + slength * sizeof(uint32));
if (!ni)
return NULL;
ni->obj = obj;
ni->props_array = ni->props_cursor = (jsval *) (ni + 1);
ni->props_end = ni->props_array + plength;
if (plength)
memcpy(ni->props_array, parray, plength * sizeof(jsval));
ni->shapes_array = (uint32 *) ni->props_end;
ni->shapes_length = slength;
ni->shapes_key = key;
ni->flags = flags;
if (slength)
memcpy(ni->shapes_array, sarray, slength * sizeof(uint32));
return ni;
}
static NativeIterator *
Snapshot(JSContext *cx, JSObject *obj, uintN flags, uint32 *sarray, uint32 slength, uint32 key)
{
HashSet<jsid> ht(cx);
if (!(flags & JSITER_OWNONLY) && !ht.init(32))
return NULL;
AutoValueVector props(cx);
JSObject *pobj = obj;
while (pobj) {
JSClass *clasp = pobj->getClass();
if (pobj->isNative() &&
pobj->map->ops->enumerate == js_Enumerate &&
!(clasp->flags & JSCLASS_NEW_ENUMERATE)) {
if (!clasp->enumerate(cx, pobj))
return NULL;
if (!EnumerateNativeProperties(cx, obj, pobj, flags, ht, props))
return NULL;
} else if (pobj->isDenseArray()) {
if (!EnumerateDenseArrayProperties(cx, obj, pobj, flags, ht, props))
return NULL;
} else {
if (pobj->isProxy()) {
JSIdArray *ida;
if (flags & JSITER_OWNONLY) {
if (!JSProxy::enumerateOwn(cx, pobj, &ida))
return NULL;
} else {
if (!JSProxy::enumerate(cx, pobj, &ida))
return NULL;
}
AutoIdArray idar(cx, ida);
for (size_t n = 0; n < size_t(ida->length); ++n) {
if (!Enumerate(cx, obj, pobj, ida->vector[n], true, flags, ht, props))
return NULL;
}
/* Proxy objects enumerate the prototype on their own, so we are done here. */
break;
}
jsval state;
if (!pobj->enumerate(cx, JSENUMERATE_INIT, &state, NULL))
return NULL;
if (state == JSVAL_NATIVE_ENUMERATE_COOKIE) {
if (!EnumerateNativeProperties(cx, obj, pobj, flags, ht, props))
return NULL;
} else {
while (true) {
jsid id;
if (!pobj->enumerate(cx, JSENUMERATE_NEXT, &state, &id))
return NULL;
if (state == JSVAL_NULL)
break;
if (!Enumerate(cx, obj, pobj, id, true, flags, ht, props))
return NULL;
}
}
}
if (JS_UNLIKELY(pobj->isXML() || (flags & JSITER_OWNONLY)))
break;
pobj = pobj->getProto();
}
return NativeIterator::allocate(cx, obj, flags, sarray, slength, key, props.begin(), props.length());
}
bool
NativeIteratorToJSIdArray(JSContext *cx, NativeIterator *ni, JSIdArray **idap)
{
/* Morph the NativeIterator into a JSIdArray. The caller will deallocate it. */
JS_ASSERT(sizeof(NativeIterator) > sizeof(JSIdArray));
JS_ASSERT(ni->props_array == (jsid *) (ni + 1));
size_t length = size_t(ni->props_end - ni->props_array);
JSIdArray *ida = (JSIdArray *) (uintptr_t(ni->props_array) - (sizeof(JSIdArray) - sizeof(jsid)));
ida->self = ni;
ida->length = length;
JS_ASSERT(&ida->vector[0] == &ni->props_array[0]);
*idap = ida;
return true;
}
bool
GetPropertyNames(JSContext *cx, JSObject *obj, uintN flags, JSIdArray **idap)
{
NativeIterator *ni = Snapshot(cx, obj, flags & (JSITER_OWNONLY | JSITER_HIDDEN), NULL, 0, true);
if (!ni)
return false;
return NativeIteratorToJSIdArray(cx, ni, idap);
}
static inline bool
GetCustomIterator(JSContext *cx, JSObject *obj, uintN flags, jsval *vp)
{
/* Check whether we have a valid __iterator__ method. */
JSAtom *atom = cx->runtime->atomState.iteratorAtom;
if (!js_GetMethod(cx, obj, ATOM_TO_JSID(atom), JSGET_NO_METHOD_BARRIER, vp))
return false;
/* If there is no custom __iterator__ method, we are done here. */
if (*vp == JSVAL_VOID)
return true;
/* Otherwise call it and return that object. */
LeaveTrace(cx);
jsval arg = BOOLEAN_TO_JSVAL((flags & JSITER_FOREACH) == 0);
if (!js_InternalCall(cx, obj, *vp, 1, &arg, vp))
return false;
if (JSVAL_IS_PRIMITIVE(*vp)) {
/*
* We are always coming from js_ValueToIterator, and we are no longer on
* trace, so the object we are iterating over is on top of the stack (-1).
*/
js_ReportValueError2(cx, JSMSG_BAD_TRAP_RETURN_VALUE,
-1, OBJECT_TO_JSVAL(obj), NULL,
js_AtomToPrintableString(cx, atom));
return false;
}
return true;
}
template <typename T>
static inline bool
Compare(T *a, T *b, size_t c)
{
size_t n = (c + size_t(7)) / size_t(8);
switch (c % 8) {
case 0: do { if (*a++ != *b++) return false;
case 7: if (*a++ != *b++) return false;
case 6: if (*a++ != *b++) return false;
case 5: if (*a++ != *b++) return false;
case 4: if (*a++ != *b++) return false;
case 3: if (*a++ != *b++) return false;
case 2: if (*a++ != *b++) return false;
case 1: if (*a++ != *b++) return false;
} while (--n > 0);
}
return true;
}
static JSObject *
NewIteratorObject(JSContext *cx, uintN flags)
{
return !(flags & JSITER_ENUMERATE)
? NewObject(cx, &js_IteratorClass.base, NULL, NULL)
: NewObjectWithGivenProto(cx, &js_IteratorClass.base, NULL, NULL);
}
static inline void
RegisterEnumerator(JSContext *cx, JSObject *iterobj, NativeIterator *ni)
{
/* Register non-escaping native enumerators (for-in) with the current context. */
if (ni->flags & JSITER_ENUMERATE) {
ni->next = cx->enumerators;
cx->enumerators = iterobj;
}
}
bool
JSIdArrayToIterator(JSContext *cx, JSObject *obj, uintN flags, JSIdArray *ida, jsval *vp)
{
JSObject *iterobj = NewIteratorObject(cx, flags);
if (!iterobj)
return false;
*vp = OBJECT_TO_JSVAL(iterobj);
NativeIterator *ni = NativeIterator::allocate(cx, obj, flags, NULL, 0, 0,
ida->vector, ida->length);
if (!ni)
return false;
iterobj->setNativeIterator(ni);
RegisterEnumerator(cx, iterobj, ni);
return true;
}
bool
GetIterator(JSContext *cx, JSObject *obj, uintN flags, jsval *vp)
{
uint32 hash;
JSObject **hp;
Vector<uint32, 8> shapes(cx);
uint32 key = 0;
bool keysOnly = (flags == JSITER_ENUMERATE);
if (obj) {
if (keysOnly) {
/*
* The iterator object for JSITER_ENUMERATE never escapes, so we
* don't care for the proper parent/proto to be set. This also
* allows us to re-use a previous iterator object that was freed
* by JSOP_ENDITER.
*/
JSObject *pobj = obj;
do {
if (!pobj->isNative() ||
obj->map->ops->enumerate != js_Enumerate ||
pobj->getClass()->enumerate != JS_EnumerateStub) {
shapes.clear();
goto miss;
}
uint32 shape = pobj->shape();
key = (key + (key << 16)) ^ shape;
if (!shapes.append(shape))
return false;
pobj = pobj->getProto();
} while (pobj);
hash = key % JS_ARRAY_LENGTH(JS_THREAD_DATA(cx)->cachedNativeIterators);
hp = &JS_THREAD_DATA(cx)->cachedNativeIterators[hash];
JSObject *iterobj = *hp;
if (iterobj) {
NativeIterator *ni = iterobj->getNativeIterator();
if (ni->shapes_key == key &&
ni->shapes_length == shapes.length() &&
Compare(ni->shapes_array, shapes.begin(), ni->shapes_length)) {
*vp = OBJECT_TO_JSVAL(iterobj);
*hp = ni->next;
RegisterEnumerator(cx, iterobj, ni);
return true;
}
}
}
miss:
if (obj->isProxy())
return JSProxy::iterate(cx, obj, flags, vp);
if (!GetCustomIterator(cx, obj, flags, vp))
return false;
if (*vp != JSVAL_VOID)
return true;
}
JSObject *iterobj = NewIteratorObject(cx, flags);
if (!iterobj)
return false;
/* Store in *vp to protect it from GC (callers must root vp). */
*vp = OBJECT_TO_JSVAL(iterobj);
NativeIterator *ni = Snapshot(cx, obj, flags, shapes.begin(), shapes.length(), key);
if (!ni)
return false;
iterobj->setNativeIterator(ni);
RegisterEnumerator(cx, iterobj, ni);
return true;
}
static JSObject *
iterator_iterator(JSContext *cx, JSObject *obj, JSBool keysonly)
{
return obj;
}
static JSBool
Iterator(JSContext *cx, JSObject *iterobj, uintN argc, jsval *argv, jsval *rval)
{
JSBool keyonly;
uintN flags;
keyonly = js_ValueToBoolean(argv[1]);
flags = JSITER_OWNONLY | (keyonly ? 0 : (JSITER_FOREACH | JSITER_KEYVALUE));
*rval = argv[0];
return js_ValueToIterator(cx, flags, rval);
}
JSBool
js_ThrowStopIteration(JSContext *cx)
{
jsval v;
JS_ASSERT(!JS_IsExceptionPending(cx));
if (js_FindClassObject(cx, NULL, JSProto_StopIteration, &v))
JS_SetPendingException(cx, v);
return JS_FALSE;
}
static JSBool
iterator_next(JSContext *cx, uintN argc, jsval *vp)
{
JSObject *obj;
obj = JS_THIS_OBJECT(cx, vp);
if (!JS_InstanceOf(cx, obj, &js_IteratorClass.base, vp + 2))
return false;
if (!js_IteratorMore(cx, obj, vp))
return false;
if (*vp == JSVAL_FALSE) {
js_ThrowStopIteration(cx);
return false;
}
JS_ASSERT(*vp == JSVAL_TRUE);
return js_IteratorNext(cx, obj, vp);
}
#define JSPROP_ROPERM (JSPROP_READONLY | JSPROP_PERMANENT)
static JSFunctionSpec iterator_methods[] = {
JS_FN(js_next_str, iterator_next, 0,JSPROP_ROPERM),
JS_FS_END
};
/*
* Call ToObject(v).__iterator__(keyonly) if ToObject(v).__iterator__ exists.
* Otherwise construct the default iterator.
*/
JS_FRIEND_API(JSBool)
js_ValueToIterator(JSContext *cx, uintN flags, jsval *vp)
{
JSObject *obj;
JSClass *clasp;
JSExtendedClass *xclasp;
JSObject *iterobj;
/* JSITER_KEYVALUE must always come with JSITER_FOREACH */
JS_ASSERT_IF(flags & JSITER_KEYVALUE, flags & JSITER_FOREACH);
/*
* Make sure the more/next state machine doesn't get stuck. A value might be
* left in iterValue when a trace is left due to an operation time-out after
* JSOP_MOREITER but before the value is picked up by FOR*.
*/
cx->iterValue = JSVAL_HOLE;
AutoValueRooter tvr(cx);
if (!JSVAL_IS_PRIMITIVE(*vp)) {
/* Common case. */
obj = JSVAL_TO_OBJECT(*vp);
} else {
/*
* Enumerating over null and undefined gives an empty enumerator.
* This is contrary to ECMA-262 9.9 ToObject, invoked from step 3 of
* the first production in 12.6.4 and step 4 of the second production,
* but it's "web JS" compatible. ES5 fixed for-in to match this de-facto
* standard.
*/
if ((flags & JSITER_ENUMERATE)) {
if (!js_ValueToObject(cx, *vp, &obj))
return false;
if (!obj)
return GetIterator(cx, obj, flags, vp);
} else {
obj = js_ValueToNonNullObject(cx, *vp);
if (!obj)
return false;
}
}
tvr.setObject(obj);
clasp = obj->getClass();
if ((clasp->flags & JSCLASS_IS_EXTENDED) &&
(xclasp = (JSExtendedClass *) clasp)->iteratorObject) {
/* Enumerate Iterator.prototype directly. */
if (clasp != &js_IteratorClass.base || obj->getNativeIterator()) {
iterobj = xclasp->iteratorObject(cx, obj, !(flags & JSITER_FOREACH));
if (!iterobj)
return false;
*vp = OBJECT_TO_JSVAL(iterobj);
return true;
}
}
return GetIterator(cx, obj, flags, vp);
}
#if JS_HAS_GENERATORS
static JS_REQUIRES_STACK JSBool
CloseGenerator(JSContext *cx, JSObject *genobj);
#endif
JS_FRIEND_API(JSBool)
js_CloseIterator(JSContext *cx, jsval v)
{
JSObject *obj;
JSClass *clasp;
cx->iterValue = JSVAL_HOLE;
JS_ASSERT(!JSVAL_IS_PRIMITIVE(v));
obj = JSVAL_TO_OBJECT(v);
clasp = obj->getClass();
if (clasp == &js_IteratorClass.base) {
/* Remove enumerators from the active list, which is a stack. */
NativeIterator *ni = obj->getNativeIterator();
if (ni->flags & JSITER_ENUMERATE) {
JS_ASSERT(cx->enumerators == obj);
cx->enumerators = ni->next;
}
/* Cache the iterator object if possible. */
if (ni->shapes_length) {
uint32 hash = ni->shapes_key % NATIVE_ITER_CACHE_SIZE;
JSObject **hp = &JS_THREAD_DATA(cx)->cachedNativeIterators[hash];
ni->props_cursor = ni->props_array;
ni->next = *hp;
*hp = obj;
} else {
iterator_finalize(cx, obj);
}
}
#if JS_HAS_GENERATORS
else if (clasp == &js_GeneratorClass.base) {
return CloseGenerator(cx, obj);
}
#endif
return JS_TRUE;
}
/*
* Suppress enumeration of deleted properties. We maintain a list of all active
* non-escaping for-in enumerators. Whenever a property is deleted, we check
* whether any active enumerator contains the (obj, id) pair and has not
* enumerated id yet. If so, we delete the id from the list (or advance the
* cursor if it is the next id to be enumerated).
*
* We do not suppress enumeration of a property deleted along an object's
* prototype chain. Only direct deletions on the object are handled.
*/
bool
js_SuppressDeletedProperty(JSContext *cx, JSObject *obj, jsid id)
{
JSObject *iterobj = cx->enumerators;
while (iterobj) {
NativeIterator *ni = iterobj->getNativeIterator();
if (ni->obj == obj && ni->props_cursor < ni->props_end) {
/* Check whether id is still to come. */
for (jsid *idp = ni->props_cursor; idp < ni->props_end; ++idp) {
if (*idp == id) {
/*
* Check whether another property along the prototype chain
* became visible as a result of this deletion.
*/
if (obj->getProto()) {
AutoObjectRooter proto(cx, obj->getProto());
AutoObjectRooter obj2(cx);
JSProperty *prop;
if (!proto.object()->lookupProperty(cx, id, obj2.addr(), &prop))
return false;
if (prop) {
uintN attrs;
if (obj2.object()->isNative()) {
attrs = ((JSScopeProperty *) prop)->attributes();
JS_UNLOCK_OBJ(cx, obj2.object());
} else if (!obj2.object()->getAttributes(cx, id, &attrs)) {
return false;
}
if (attrs & JSPROP_ENUMERATE)
continue;
}
}
/*
* No property along the prototype chain steppeded in to take the
* property's place, so go ahead and delete id from the list.
* If it is the next property to be enumerated, just skip it.
*/
if (idp == ni->props_cursor) {
ni->props_cursor++;
} else {
memmove(idp, idp + 1, (ni->props_end - (idp + 1)) * sizeof(jsid));
ni->props_end--;
}
break;
}
}
}
iterobj = ni->next;
}
return true;
}
JSBool
js_IteratorMore(JSContext *cx, JSObject *iterobj, jsval *rval)
{
/* Fast path for native iterators */
if (iterobj->getClass() == &js_IteratorClass.base) {
/*
* Implement next directly as all the methods of native iterator are
* read-only and permanent.
*/
NativeIterator *ni = iterobj->getNativeIterator();
*rval = BOOLEAN_TO_JSVAL(ni->props_cursor < ni->props_end);
return true;
}
/* We might still have a pending value. */
if (cx->iterValue != JSVAL_HOLE) {
*rval = JSVAL_TRUE;
return true;
}
/* Fetch and cache the next value from the iterator. */
jsid id = ATOM_TO_JSID(cx->runtime->atomState.nextAtom);
if (!JS_GetMethodById(cx, iterobj, id, &iterobj, rval))
return false;
if (!js_InternalCall(cx, iterobj, *rval, 0, NULL, rval)) {
/* Check for StopIteration. */
if (!cx->throwing || !js_ValueIsStopIteration(cx->exception))
return false;
/* Inline JS_ClearPendingException(cx). */
cx->throwing = JS_FALSE;
cx->exception = JSVAL_VOID;
cx->iterValue = JSVAL_HOLE;
*rval = JSVAL_FALSE;
return true;
}
/* Cache the value returned by iterobj.next() so js_IteratorNext() can find it. */
JS_ASSERT(*rval != JSVAL_HOLE);
cx->iterValue = *rval;
*rval = JSVAL_TRUE;
return true;
}
JSBool
js_IteratorNext(JSContext *cx, JSObject *iterobj, jsval *rval)
{
/* Fast path for native iterators */
if (iterobj->getClass() == &js_IteratorClass.base) {
/*
* Implement next directly as all the methods of the native iterator are
* read-only and permanent.
*/
NativeIterator *ni = iterobj->getNativeIterator();
JS_ASSERT(ni->props_cursor < ni->props_end);
*rval = *ni->props_cursor++;
if (JSVAL_IS_STRING(*rval) || (ni->flags & JSITER_FOREACH))
return true;
JSString *str;
jsint i;
if (JSVAL_IS_INT(*rval) && (jsuint(i = JSVAL_TO_INT(*rval)) < INT_STRING_LIMIT)) {
str = JSString::intString(i);
} else {
str = js_ValueToString(cx, *rval);
if (!str)
return false;
}
*rval = STRING_TO_JSVAL(str);
return true;
}
JS_ASSERT(cx->iterValue != JSVAL_HOLE);
*rval = cx->iterValue;
cx->iterValue = JSVAL_HOLE;
return true;
}
static JSBool
stopiter_hasInstance(JSContext *cx, JSObject *obj, jsval v, JSBool *bp)
{
*bp = js_ValueIsStopIteration(v);
return JS_TRUE;
}
JSClass js_StopIterationClass = {
js_StopIteration_str,
JSCLASS_HAS_CACHED_PROTO(JSProto_StopIteration),
JS_PropertyStub, JS_PropertyStub,
JS_PropertyStub, JS_PropertyStub,
JS_EnumerateStub, JS_ResolveStub,
JS_ConvertStub, NULL,
NULL, NULL,
NULL, NULL,
NULL, stopiter_hasInstance,
NULL, NULL
};
#if JS_HAS_GENERATORS
static void
generator_finalize(JSContext *cx, JSObject *obj)
{
JSGenerator *gen = (JSGenerator *) obj->getPrivate();
if (!gen)
return;
/*
* gen is open when a script has not called its close method while
* explicitly manipulating it.
*/
JS_ASSERT(gen->state == JSGEN_NEWBORN ||
gen->state == JSGEN_CLOSED ||
gen->state == JSGEN_OPEN);
cx->free(gen);
}
static void
generator_trace(JSTracer *trc, JSObject *obj)
{
JSGenerator *gen = (JSGenerator *) obj->getPrivate();
if (!gen)
return;
/*
* Do not mark if the generator is running; the contents may be trash and
* will be replaced when the generator stops.
*/
if (gen->state == JSGEN_RUNNING || gen->state == JSGEN_CLOSING)
return;
JSStackFrame *fp = gen->getFloatingFrame();
JS_ASSERT(gen->getLiveFrame() == fp);
TraceValues(trc, gen->floatingStack, fp->argEnd(), "generator slots");
js_TraceStackFrame(trc, fp);
TraceValues(trc, fp->slots(), gen->savedRegs.sp, "generator slots");
}
JSExtendedClass js_GeneratorClass = {
{ js_Generator_str,
JSCLASS_HAS_PRIVATE |
JSCLASS_HAS_CACHED_PROTO(JSProto_Generator) |
JSCLASS_IS_ANONYMOUS |
JSCLASS_MARK_IS_TRACE |
JSCLASS_IS_EXTENDED,
JS_PropertyStub, JS_PropertyStub, JS_PropertyStub, JS_PropertyStub,
JS_EnumerateStub, JS_ResolveStub, JS_ConvertStub, generator_finalize,
NULL, NULL, NULL, NULL,
NULL, NULL, JS_CLASS_TRACE(generator_trace), NULL },
NULL, NULL, NULL, iterator_iterator,
NULL,
JSCLASS_NO_RESERVED_MEMBERS
};
/*
* Called from the JSOP_GENERATOR case in the interpreter, with fp referring
* to the frame by which the generator function was activated. Create a new
* JSGenerator object, which contains its own JSStackFrame that we populate
* from *fp. We know that upon return, the JSOP_GENERATOR opcode will return
* from the activation in fp, so we can steal away fp->callobj and fp->argsobj
* if they are non-null.
*/
JS_REQUIRES_STACK JSObject *
js_NewGenerator(JSContext *cx)
{
JSObject *obj = NewObject(cx, &js_GeneratorClass.base, NULL, NULL);
if (!obj)
return NULL;
/* Load and compute stack slot counts. */
JSStackFrame *fp = cx->fp;
uintN argc = fp->argc;
uintN nargs = JS_MAX(argc, fp->fun->nargs);
uintN vplen = 2 + nargs;
/* Compute JSGenerator size. */
uintN nbytes = sizeof(JSGenerator) +
(-1 + /* one jsval included in JSGenerator */
vplen +
VALUES_PER_STACK_FRAME +
fp->script->nslots) * sizeof(jsval);
JSGenerator *gen = (JSGenerator *) cx->malloc(nbytes);
if (!gen)
return NULL;
/* Cut up floatingStack space. */
jsval *vp = gen->floatingStack;
JSStackFrame *newfp = reinterpret_cast<JSStackFrame *>(vp + vplen);
jsval *slots = newfp->slots();
/* Initialize JSGenerator. */
gen->obj = obj;
gen->state = JSGEN_NEWBORN;
gen->savedRegs.pc = cx->regs->pc;
JS_ASSERT(cx->regs->sp == fp->slots() + fp->script->nfixed);
gen->savedRegs.sp = slots + fp->script->nfixed;
gen->vplen = vplen;
gen->enumerators = NULL;
gen->liveFrame = newfp;
/* Copy generator's stack frame copy in from |cx->fp|. */
newfp->imacpc = NULL;
newfp->callobj = fp->callobj;
if (fp->callobj) { /* Steal call object. */
fp->callobj->setPrivate(newfp);
fp->callobj = NULL;
}
newfp->argsobj = fp->argsobj;
if (fp->argsobj) { /* Steal args object. */
JSVAL_TO_OBJECT(fp->argsobj)->setPrivate(newfp);
fp->argsobj = NULL;
}
newfp->script = fp->script;
newfp->fun = fp->fun;
newfp->thisv = fp->thisv;
newfp->argc = fp->argc;
newfp->argv = vp + 2;
newfp->rval = fp->rval;
newfp->annotation = NULL;
newfp->scopeChain = fp->scopeChain;
JS_ASSERT(!fp->blockChain);
newfp->blockChain = NULL;
newfp->flags = fp->flags | JSFRAME_GENERATOR | JSFRAME_FLOATING_GENERATOR;
/* Copy in arguments and slots. */
memcpy(vp, fp->argv - 2, vplen * sizeof(jsval));
memcpy(slots, fp->slots(), fp->script->nfixed * sizeof(jsval));
obj->setPrivate(gen);
return obj;
}
JSGenerator *
js_FloatingFrameToGenerator(JSStackFrame *fp)
{
JS_ASSERT(fp->isGenerator() && fp->isFloatingGenerator());
char *floatingStackp = (char *)(fp->argv - 2);
char *p = floatingStackp - offsetof(JSGenerator, floatingStack);
return reinterpret_cast<JSGenerator *>(p);
}
typedef enum JSGeneratorOp {
JSGENOP_NEXT,
JSGENOP_SEND,
JSGENOP_THROW,
JSGENOP_CLOSE
} JSGeneratorOp;
/*
* Start newborn or restart yielding generator and perform the requested
* operation inside its frame.
*/
static JS_REQUIRES_STACK JSBool
SendToGenerator(JSContext *cx, JSGeneratorOp op, JSObject *obj,
JSGenerator *gen, jsval arg)
{
if (gen->state == JSGEN_RUNNING || gen->state == JSGEN_CLOSING) {
js_ReportValueError(cx, JSMSG_NESTING_GENERATOR,
JSDVG_SEARCH_STACK, OBJECT_TO_JSVAL(obj),
JS_GetFunctionId(gen->getFloatingFrame()->fun));
return JS_FALSE;
}
/* Check for OOM errors here, where we can fail easily. */
if (!cx->ensureGeneratorStackSpace())
return JS_FALSE;
JS_ASSERT(gen->state == JSGEN_NEWBORN || gen->state == JSGEN_OPEN);
switch (op) {
case JSGENOP_NEXT:
case JSGENOP_SEND:
if (gen->state == JSGEN_OPEN) {
/*
* Store the argument to send as the result of the yield
* expression.
*/
gen->savedRegs.sp[-1] = arg;
}
gen->state = JSGEN_RUNNING;
break;
case JSGENOP_THROW:
JS_SetPendingException(cx, arg);
gen->state = JSGEN_RUNNING;
break;
default:
JS_ASSERT(op == JSGENOP_CLOSE);
JS_SetPendingException(cx, JSVAL_ARETURN);
gen->state = JSGEN_CLOSING;
break;
}
JSStackFrame *genfp = gen->getFloatingFrame();
JSBool ok;
{
jsval *genVp = gen->floatingStack;
uintN vplen = gen->vplen;
uintN nfixed = genfp->script->nslots;
/*
* Get a pointer to new frame/slots. This memory is not "claimed", so
* the code before pushExecuteFrame must not reenter the interpreter.
*/
ExecuteFrameGuard frame;
if (!cx->stack().getExecuteFrame(cx, cx->fp, vplen, nfixed, frame)) {
gen->state = JSGEN_CLOSED;
return JS_FALSE;
}
jsval *vp = frame.getvp();
JSStackFrame *fp = frame.getFrame();
/*
* Copy and rebase stack frame/args/slots. The "floating" flag must
* only be set on the generator's frame. See args_or_call_trace.
*/
uintN usedBefore = gen->savedRegs.sp - genVp;
memcpy(vp, genVp, usedBefore * sizeof(jsval));
fp->flags &= ~JSFRAME_FLOATING_GENERATOR;
fp->argv = vp + 2;
gen->savedRegs.sp = fp->slots() + (gen->savedRegs.sp - genfp->slots());
JS_ASSERT(uintN(gen->savedRegs.sp - fp->slots()) <= fp->script->nslots);
#ifdef DEBUG
JSObject *callobjBefore = fp->callobj;
jsval argsobjBefore = fp->argsobj;
#endif
/*
* Repoint Call, Arguments, Block and With objects to the new live
* frame. Call and Arguments are done directly because we have
* pointers to them. Block and With objects are done indirectly through
* 'liveFrame'. See js_LiveFrameToFloating comment in jsiter.h.
*/
if (genfp->callobj)
fp->callobj->setPrivate(fp);
if (genfp->argsobj)
JSVAL_TO_OBJECT(fp->argsobj)->setPrivate(fp);
gen->liveFrame = fp;
(void)cx->enterGenerator(gen); /* OOM check above. */
/* Officially push |fp|. |frame|'s destructor pops. */
cx->stack().pushExecuteFrame(cx, frame, gen->savedRegs, NULL);
/* Swap the enumerators stack for the generator's stack. */
JSObject *enumerators = cx->enumerators;
cx->enumerators = gen->enumerators;
ok = js_Interpret(cx);
/* Restore the original enumerators stack. */
gen->enumerators = cx->enumerators;
cx->enumerators = enumerators;
/* Restore call/args/block objects. */
cx->leaveGenerator(gen);
gen->liveFrame = genfp;
if (fp->argsobj)
JSVAL_TO_OBJECT(fp->argsobj)->setPrivate(genfp);
if (fp->callobj)
fp->callobj->setPrivate(genfp);
JS_ASSERT_IF(argsobjBefore, argsobjBefore == fp->argsobj);
JS_ASSERT_IF(callobjBefore, callobjBefore == fp->callobj);
/* Copy and rebase stack frame/args/slots. Restore "floating" flag. */
JS_ASSERT(uintN(gen->savedRegs.sp - fp->slots()) <= fp->script->nslots);
uintN usedAfter = gen->savedRegs.sp - vp;
memcpy(genVp, vp, usedAfter * sizeof(jsval));
genfp->flags |= JSFRAME_FLOATING_GENERATOR;
genfp->argv = genVp + 2;
gen->savedRegs.sp = genfp->slots() + (gen->savedRegs.sp - fp->slots());
JS_ASSERT(uintN(gen->savedRegs.sp - genfp->slots()) <= genfp->script->nslots);
}
if (gen->getFloatingFrame()->flags & JSFRAME_YIELDING) {
/* Yield cannot fail, throw or be called on closing. */
JS_ASSERT(ok);
JS_ASSERT(!cx->throwing);
JS_ASSERT(gen->state == JSGEN_RUNNING);
JS_ASSERT(op != JSGENOP_CLOSE);
genfp->flags &= ~JSFRAME_YIELDING;
gen->state = JSGEN_OPEN;
return JS_TRUE;
}
genfp->rval = JSVAL_VOID;
gen->state = JSGEN_CLOSED;
if (ok) {
/* Returned, explicitly or by falling off the end. */
if (op == JSGENOP_CLOSE)
return JS_TRUE;
return js_ThrowStopIteration(cx);
}
/*
* An error, silent termination by operation callback or an exception.
* Propagate the condition to the caller.
*/
return JS_FALSE;
}
static JS_REQUIRES_STACK JSBool
CloseGenerator(JSContext *cx, JSObject *obj)
{
JS_ASSERT(obj->getClass() == &js_GeneratorClass.base);
JSGenerator *gen = (JSGenerator *) obj->getPrivate();
if (!gen) {
/* Generator prototype object. */
return JS_TRUE;
}
if (gen->state == JSGEN_CLOSED)
return JS_TRUE;
return SendToGenerator(cx, JSGENOP_CLOSE, obj, gen, JSVAL_VOID);
}
/*
* Common subroutine of generator_(next|send|throw|close) methods.
*/
static JSBool
generator_op(JSContext *cx, JSGeneratorOp op, jsval *vp, uintN argc)
{
JSObject *obj;
jsval arg;
LeaveTrace(cx);
obj = JS_THIS_OBJECT(cx, vp);
if (!JS_InstanceOf(cx, obj, &js_GeneratorClass.base, vp + 2))
return JS_FALSE;
JSGenerator *gen = (JSGenerator *) obj->getPrivate();
if (!gen) {
/* This happens when obj is the generator prototype. See bug 352885. */
goto closed_generator;
}
if (gen->state == JSGEN_NEWBORN) {
switch (op) {
case JSGENOP_NEXT:
case JSGENOP_THROW:
break;
case JSGENOP_SEND:
if (argc >= 1 && !JSVAL_IS_VOID(vp[2])) {
js_ReportValueError(cx, JSMSG_BAD_GENERATOR_SEND,
JSDVG_SEARCH_STACK, vp[2], NULL);
return JS_FALSE;
}
break;
default:
JS_ASSERT(op == JSGENOP_CLOSE);
gen->state = JSGEN_CLOSED;
return JS_TRUE;
}
} else if (gen->state == JSGEN_CLOSED) {
closed_generator:
switch (op) {
case JSGENOP_NEXT:
case JSGENOP_SEND:
return js_ThrowStopIteration(cx);
case JSGENOP_THROW:
JS_SetPendingException(cx, argc >= 1 ? vp[2] : JSVAL_VOID);
return JS_FALSE;
default:
JS_ASSERT(op == JSGENOP_CLOSE);
return JS_TRUE;
}
}
arg = ((op == JSGENOP_SEND || op == JSGENOP_THROW) && argc != 0)
? vp[2]
: JSVAL_VOID;
if (!SendToGenerator(cx, op, obj, gen, arg))
return JS_FALSE;
*vp = gen->getFloatingFrame()->rval;
return JS_TRUE;
}
static JSBool
generator_send(JSContext *cx, uintN argc, jsval *vp)
{
return generator_op(cx, JSGENOP_SEND, vp, argc);
}
static JSBool
generator_next(JSContext *cx, uintN argc, jsval *vp)
{
return generator_op(cx, JSGENOP_NEXT, vp, argc);
}
static JSBool
generator_throw(JSContext *cx, uintN argc, jsval *vp)
{
return generator_op(cx, JSGENOP_THROW, vp, argc);
}
static JSBool
generator_close(JSContext *cx, uintN argc, jsval *vp)
{
return generator_op(cx, JSGENOP_CLOSE, vp, argc);
}
static JSFunctionSpec generator_methods[] = {
JS_FN(js_next_str, generator_next, 0,JSPROP_ROPERM),
JS_FN(js_send_str, generator_send, 1,JSPROP_ROPERM),
JS_FN(js_throw_str, generator_throw, 1,JSPROP_ROPERM),
JS_FN(js_close_str, generator_close, 0,JSPROP_ROPERM),
JS_FS_END
};
#endif /* JS_HAS_GENERATORS */
JSObject *
js_InitIteratorClasses(JSContext *cx, JSObject *obj)
{
JSObject *proto, *stop;
/* Idempotency required: we initialize several things, possibly lazily. */
if (!js_GetClassObject(cx, obj, JSProto_StopIteration, &stop))
return NULL;
if (stop)
return stop;
proto = JS_InitClass(cx, obj, NULL, &js_IteratorClass.base, Iterator, 2,
NULL, iterator_methods, NULL, NULL);
if (!proto)
return NULL;
#if JS_HAS_GENERATORS
/* Initialize the generator internals if configured. */
if (!JS_InitClass(cx, obj, NULL, &js_GeneratorClass.base, NULL, 0,
NULL, generator_methods, NULL, NULL)) {
return NULL;
}
#endif
return JS_InitClass(cx, obj, NULL, &js_StopIterationClass, NULL, 0,
NULL, NULL, NULL, NULL);
}
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