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gecko/js/src/jsiter.cpp

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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 "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 "jsversion.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 "jsscan.h"
#include "jsscope.h"
#include "jsscript.h"
#if JS_HAS_XML_SUPPORT
#include "jsxml.h"
#endif
#if JSSLOT_ITER_FLAGS >= JS_INITIAL_NSLOTS
#error JS_INITIAL_NSLOTS must be greater than JSSLOT_ITER_FLAGS.
#endif
#if JS_HAS_GENERATORS
static JSBool
CloseGenerator(JSContext *cx, JSObject *genobj);
#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_CloseNativeIterator(JSContext *cx, JSObject *iterobj)
{
jsval state;
JSObject *iterable;
JS_ASSERT(STOBJ_GET_CLASS(iterobj) == &js_IteratorClass);
/* Avoid double work if js_CloseNativeIterator was called on obj. */
state = STOBJ_GET_SLOT(iterobj, JSSLOT_ITER_STATE);
if (JSVAL_IS_NULL(state))
return;
/* Protect against failure to fully initialize obj. */
iterable = STOBJ_GET_PARENT(iterobj);
if (iterable) {
#if JS_HAS_XML_SUPPORT
uintN flags = JSVAL_TO_INT(STOBJ_GET_SLOT(iterobj, JSSLOT_ITER_FLAGS));
if ((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);
}
STOBJ_SET_SLOT(iterobj, 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(STOBJ_GET_CLASS(iterobj) == &js_IteratorClass);
/* Initialize iterobj in case of enumerate hook failure. */
STOBJ_SET_PARENT(iterobj, obj);
STOBJ_SET_SLOT(iterobj, JSSLOT_ITER_STATE, JSVAL_NULL);
STOBJ_SET_SLOT(iterobj, 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;
STOBJ_SET_SLOT(iterobj, 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);
STOBJ_SET_PROTO(iterobj, 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_ValueToBoolean(argv[1]);
flags = keyonly ? 0 : JSITER_FOREACH;
if (JS_IsConstructing(cx)) {
/* 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 = STOBJ_GET_SLOT(obj, JSSLOT_ITER_STATE);
if (JSVAL_IS_NULL(state))
goto stop;
flags = JSVAL_TO_INT(STOBJ_GET_SLOT(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;
STOBJ_SET_SLOT(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(STOBJ_GET_SLOT(obj, JSSLOT_ITER_STATE) == JSVAL_NULL);
*rval = JSVAL_HOLE;
return JS_TRUE;
}
JSBool
js_ThrowStopIteration(JSContext *cx)
{
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, uintN argc, jsval *vp)
{
JSObject *obj;
obj = JS_THIS_OBJECT(cx, vp);
if (!JS_InstanceOf(cx, obj, &js_IteratorClass, vp + 2))
return JS_FALSE;
if (!IteratorNextImpl(cx, obj, vp))
return JS_FALSE;
if (*vp == JSVAL_HOLE) {
*vp = JSVAL_NULL;
js_ThrowStopIteration(cx);
return JS_FALSE;
}
return JS_TRUE;
}
static JSBool
iterator_self(JSContext *cx, uintN argc, jsval *vp)
{
*vp = JS_THIS(cx, vp);
return !JSVAL_IS_NULL(*vp);
}
#define JSPROP_ROPERM (JSPROP_READONLY | JSPROP_PERMANENT)
static JSFunctionSpec iterator_methods[] = {
JS_FN(js_iterator_str, iterator_self, 0,JSPROP_ROPERM),
JS_FN(js_next_str, iterator_next, 0,JSPROP_ROPERM),
JS_FS_END
};
uintN
js_GetNativeIteratorFlags(JSContext *cx, JSObject *iterobj)
{
if (OBJ_GET_CLASS(cx, iterobj) != &js_IteratorClass)
return 0;
return JSVAL_TO_INT(STOBJ_GET_SLOT(iterobj, JSSLOT_ITER_FLAGS));
}
/*
* 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;
JSTempValueRooter tvr;
JSAtom *atom;
JSClass *clasp;
JSExtendedClass *xclasp;
JSBool ok;
JSObject *iterobj;
jsval arg;
JS_ASSERT(!(flags & ~(JSITER_ENUMERATE |
JSITER_FOREACH |
JSITER_KEYVALUE)));
/* JSITER_KEYVALUE must always come with JSITER_FOREACH */
JS_ASSERT(!(flags & JSITER_KEYVALUE) || (flags & JSITER_FOREACH));
/* XXX work around old valueOf call hidden beneath js_ValueToObject */
if (!JSVAL_IS_PRIMITIVE(*vp)) {
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.
*/
if ((flags & JSITER_ENUMERATE)) {
if (!js_ValueToObject(cx, *vp, &obj))
return JS_FALSE;
if (!obj)
goto default_iter;
} else {
obj = js_ValueToNonNullObject(cx, *vp);
if (!obj)
return JS_FALSE;
}
}
JS_ASSERT(obj);
JS_PUSH_TEMP_ROOT_OBJECT(cx, obj, &tvr);
clasp = OBJ_GET_CLASS(cx, obj);
if ((clasp->flags & JSCLASS_IS_EXTENDED) &&
(xclasp = (JSExtendedClass *) clasp)->iteratorObject) {
iterobj = xclasp->iteratorObject(cx, obj, !(flags & JSITER_FOREACH));
if (!iterobj)
goto bad;
*vp = OBJECT_TO_JSVAL(iterobj);
} else {
atom = cx->runtime->atomState.iteratorAtom;
#if JS_HAS_XML_SUPPORT
if (OBJECT_IS_XML(cx, obj)) {
if (!js_GetXMLFunction(cx, obj, ATOM_TO_JSID(atom), vp))
goto bad;
} else
#endif
{
if (!OBJ_GET_PROPERTY(cx, obj, ATOM_TO_JSID(atom), vp))
goto bad;
}
if (JSVAL_IS_VOID(*vp)) {
default_iter:
/*
* Fail over to the default enumerating native iterator.
*
* Create iterobj with a NULL parent to ensure that we use the
* correct scope chain to lookup the iterator's constructor. Since
* we use the parent slot to keep track of the iterable, we must
* fix it up after.
*/
iterobj = js_NewObject(cx, &js_IteratorClass, NULL, NULL, 0);
if (!iterobj)
goto bad;
/* Store in *vp to protect it from GC (callers must root vp). */
*vp = OBJECT_TO_JSVAL(iterobj);
if (!InitNativeIterator(cx, iterobj, obj, flags))
goto bad;
} else {
arg = BOOLEAN_TO_JSVAL((flags & JSITER_FOREACH) == 0);
if (!js_InternalInvoke(cx, obj, *vp, JSINVOKE_ITERATOR, 1, &arg,
vp)) {
goto bad;
}
if (JSVAL_IS_PRIMITIVE(*vp)) {
const char *printable = js_AtomToPrintableString(cx, atom);
if (printable) {
js_ReportValueError2(cx, JSMSG_BAD_ITERATOR_RETURN,
JSDVG_SEARCH_STACK, *vp, NULL,
printable);
}
goto bad;
}
}
}
ok = JS_TRUE;
out:
if (obj)
JS_POP_TEMP_ROOT(cx, &tvr);
return ok;
bad:
ok = JS_FALSE;
goto out;
}
JS_FRIEND_API(JSBool) JS_FASTCALL
js_CloseIterator(JSContext *cx, jsval v)
{
JSObject *obj;
JSClass *clasp;
JS_ASSERT(!JSVAL_IS_PRIMITIVE(v));
obj = JSVAL_TO_OBJECT(v);
clasp = OBJ_GET_CLASS(cx, obj);
if (clasp == &js_IteratorClass) {
js_CloseNativeIterator(cx, obj);
}
#if JS_HAS_GENERATORS
else if (clasp == &js_GeneratorClass) {
if (!CloseGenerator(cx, obj))
return JS_FALSE;
}
#endif
return JS_TRUE;
}
static JSBool
CallEnumeratorNext(JSContext *cx, JSObject *iterobj, uintN flags, jsval *rval)
{
JSObject *obj, *origobj;
jsval state;
JSBool foreach;
jsid id;
JSObject *obj2;
JSBool cond;
JSClass *clasp;
JSExtendedClass *xclasp;
JSProperty *prop;
JSString *str;
JS_ASSERT(flags & JSITER_ENUMERATE);
JS_ASSERT(STOBJ_GET_CLASS(iterobj) == &js_IteratorClass);
obj = STOBJ_GET_PARENT(iterobj);
origobj = STOBJ_GET_PROTO(iterobj);
state = STOBJ_GET_SLOT(iterobj, JSSLOT_ITER_STATE);
if (JSVAL_IS_NULL(state))
goto stop;
foreach = (flags & JSITER_FOREACH) != 0;
#if JS_HAS_XML_SUPPORT
/*
* Treat an XML object specially only when it starts the prototype chain.
* Otherwise we need to do the usual deleted and shadowed property checks.
*/
if (obj == origobj && OBJECT_IS_XML(cx, obj)) {
if (foreach) {
JSXMLObjectOps *xmlops = (JSXMLObjectOps *) obj->map->ops;
if (!xmlops->enumerateValues(cx, obj, JSENUMERATE_NEXT, &state,
&id, rval)) {
return JS_FALSE;
}
} else {
if (!OBJ_ENUMERATE(cx, obj, JSENUMERATE_NEXT, &state, &id))
return JS_FALSE;
}
STOBJ_SET_SLOT(iterobj, JSSLOT_ITER_STATE, state);
if (JSVAL_IS_NULL(state))
goto stop;
} else
#endif
{
restart:
if (!OBJ_ENUMERATE(cx, obj, JSENUMERATE_NEXT, &state, &id))
return JS_FALSE;
STOBJ_SET_SLOT(iterobj, JSSLOT_ITER_STATE, state);
if (JSVAL_IS_NULL(state)) {
#if JS_HAS_XML_SUPPORT
if (OBJECT_IS_XML(cx, obj)) {
/*
* We just finished enumerating an XML obj that is present on
* the prototype chain of a non-XML origobj. Stop further
* prototype chain searches because XML objects don't
* enumerate prototypes.
*/
JS_ASSERT(origobj != obj);
JS_ASSERT(!OBJECT_IS_XML(cx, origobj));
} else
#endif
{
obj = OBJ_GET_PROTO(cx, obj);
if (obj) {
STOBJ_SET_PARENT(iterobj, obj);
if (!OBJ_ENUMERATE(cx, obj, JSENUMERATE_INIT, &state, NULL))
return JS_FALSE;
STOBJ_SET_SLOT(iterobj, JSSLOT_ITER_STATE, state);
if (!JSVAL_IS_NULL(state))
goto restart;
}
}
goto stop;
}
/* Skip properties not in obj when looking from origobj. */
if (!OBJ_LOOKUP_PROPERTY(cx, origobj, id, &obj2, &prop))
return JS_FALSE;
if (!prop)
goto restart;
OBJ_DROP_PROPERTY(cx, obj2, prop);
/*
* If the id was found in a prototype object or an unrelated object
* (specifically, not in an inner object for obj), skip it. This step
* means that all OBJ_LOOKUP_PROPERTY implementations must return an
* object further along on the prototype chain, or else possibly an
* object returned by the JSExtendedClass.outerObject optional hook.
*/
if (obj != obj2) {
cond = JS_FALSE;
clasp = OBJ_GET_CLASS(cx, obj2);
if (clasp->flags & JSCLASS_IS_EXTENDED) {
xclasp = (JSExtendedClass *) clasp;
cond = xclasp->outerObject &&
xclasp->outerObject(cx, obj2) == obj;
}
if (!cond)
goto restart;
}
if (foreach) {
/* Get property querying the original object. */
if (!OBJ_GET_PROPERTY(cx, origobj, id, rval))
return JS_FALSE;
}
}
if (foreach) {
if (flags & JSITER_KEYVALUE) {
if (!NewKeyValuePair(cx, id, *rval, rval))
return JS_FALSE;
}
} else {
/* Make rval a string for uniformity and compatibility. */
str = js_ValueToString(cx, ID_TO_VALUE(id));
if (!str)
return JS_FALSE;
*rval = STRING_TO_JSVAL(str);
}
return JS_TRUE;
stop:
JS_ASSERT(STOBJ_GET_SLOT(iterobj, JSSLOT_ITER_STATE) == JSVAL_NULL);
*rval = JSVAL_HOLE;
return JS_TRUE;
}
JS_FRIEND_API(JSBool)
js_CallIteratorNext(JSContext *cx, JSObject *iterobj, jsval *rval)
{
uintN flags;
/* Fast path for native iterators */
if (OBJ_GET_CLASS(cx, iterobj) == &js_IteratorClass) {
flags = JSVAL_TO_INT(STOBJ_GET_SLOT(iterobj, JSSLOT_ITER_FLAGS));
if (flags & JSITER_ENUMERATE)
return CallEnumeratorNext(cx, iterobj, flags, rval);
/*
* Call next directly as all the methods of the native iterator are
* read-only and permanent.
*/
if (!IteratorNextImpl(cx, iterobj, rval))
return JS_FALSE;
} else {
jsid id = ATOM_TO_JSID(cx->runtime->atomState.nextAtom);
if (!JS_GetMethodById(cx, iterobj, id, &iterobj, rval))
return JS_FALSE;
if (!js_InternalCall(cx, iterobj, *rval, 0, NULL, rval)) {
/* Check for StopIteration. */
if (!cx->throwing || !js_ValueIsStopIteration(cx->exception))
return JS_FALSE;
/* Inline JS_ClearPendingException(cx). */
cx->throwing = JS_FALSE;
cx->exception = JSVAL_VOID;
*rval = JSVAL_HOLE;
return JS_TRUE;
}
}
return JS_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, JS_FinalizeStub,
NULL, NULL,
NULL, NULL,
NULL, stopiter_hasInstance,
NULL, NULL
};
#if JS_HAS_GENERATORS
static void
generator_finalize(JSContext *cx, JSObject *obj)
{
JSGenerator *gen;
gen = (JSGenerator *) JS_GetPrivate(cx, obj);
if (gen) {
/*
* gen can be open on shutdown when close hooks are ignored or when
* the embedding cancels scheduled close hooks.
*/
JS_ASSERT(gen->state == JSGEN_NEWBORN || gen->state == JSGEN_CLOSED ||
gen->state == JSGEN_OPEN);
JS_free(cx, gen);
}
}
static void
generator_trace(JSTracer *trc, JSObject *obj)
{
JSGenerator *gen;
gen = (JSGenerator *) JS_GetPrivate(trc->context, obj);
if (!gen)
return;
/*
* js_TraceStackFrame does not recursively trace the down-linked frame
* chain, so we insist that gen->frame has no parent to trace when the
* generator is not running.
*/
JS_ASSERT_IF(gen->state != JSGEN_RUNNING && gen->state != JSGEN_CLOSING,
!gen->frame.down);
/*
* FIXME be 390950. Generator's frame is a part of the JS stack when the
* generator is running or closing. Thus tracing the frame in this case
* here duplicates the work done in js_TraceContext.
*/
js_TraceStackFrame(trc, &gen->frame);
}
JSClass js_GeneratorClass = {
js_Generator_str,
JSCLASS_HAS_PRIVATE | JSCLASS_IS_ANONYMOUS |
JSCLASS_MARK_IS_TRACE | JSCLASS_HAS_CACHED_PROTO(JSProto_Generator),
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
};
/*
* 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.
*/
JSObject *
js_NewGenerator(JSContext *cx, JSStackFrame *fp)
{
JSObject *obj;
uintN argc, nargs, nslots;
JSGenerator *gen;
jsval *slots;
/* After the following return, failing control flow must goto bad. */
obj = js_NewObject(cx, &js_GeneratorClass, NULL, NULL, 0);
if (!obj)
return NULL;
/* Load and compute stack slot counts. */
argc = fp->argc;
nargs = JS_MAX(argc, fp->fun->nargs);
nslots = 2 + nargs + fp->script->nslots;
/* Allocate obj's private data struct. */
gen = (JSGenerator *)
JS_malloc(cx, sizeof(JSGenerator) + (nslots - 1) * sizeof(jsval));
if (!gen)
goto bad;
gen->obj = obj;
/* Steal away objects reflecting fp and point them at gen->frame. */
gen->frame.callobj = fp->callobj;
if (fp->callobj) {
JS_SetPrivate(cx, fp->callobj, &gen->frame);
fp->callobj = NULL;
}
gen->frame.argsobj = fp->argsobj;
if (fp->argsobj) {
JS_SetPrivate(cx, fp->argsobj, &gen->frame);
fp->argsobj = NULL;
}
/* These two references can be shared with fp until it goes away. */
gen->frame.varobj = fp->varobj;
gen->frame.thisp = fp->thisp;
/* Copy call-invariant script and function references. */
gen->frame.script = fp->script;
gen->frame.callee = fp->callee;
gen->frame.fun = fp->fun;
/* Use slots to carve space out of gen->slots. */
slots = gen->slots;
gen->arena.next = NULL;
gen->arena.base = (jsuword) slots;
gen->arena.limit = gen->arena.avail = (jsuword) (slots + nslots);
/* Copy rval, argv and vars. */
gen->frame.rval = fp->rval;
memcpy(slots, fp->argv - 2, (2 + nargs) * sizeof(jsval));
gen->frame.argc = nargs;
gen->frame.argv = slots + 2;
slots += 2 + nargs;
memcpy(slots, fp->slots, fp->script->nfixed * sizeof(jsval));
/* Initialize or copy virtual machine state. */
gen->frame.down = NULL;
gen->frame.annotation = NULL;
gen->frame.scopeChain = fp->scopeChain;
gen->frame.imacpc = NULL;
gen->frame.slots = slots;
JS_ASSERT(StackBase(fp) == fp->regs->sp);
gen->savedRegs.sp = slots + fp->script->nfixed;
gen->savedRegs.pc = fp->regs->pc;
gen->frame.regs = &gen->savedRegs;
/* Copy remaining state (XXX sharp* and xml* should be local vars). */
gen->frame.sharpDepth = 0;
gen->frame.sharpArray = NULL;
gen->frame.flags = (fp->flags & ~JSFRAME_ROOTED_ARGV) | JSFRAME_GENERATOR;
gen->frame.dormantNext = NULL;
gen->frame.xmlNamespace = NULL;
gen->frame.blockChain = NULL;
/* Note that gen is newborn. */
gen->state = JSGEN_NEWBORN;
if (!JS_SetPrivate(cx, obj, gen)) {
JS_free(cx, gen);
goto bad;
}
return obj;
bad:
cx->weakRoots.newborn[GCX_OBJECT] = NULL;
return NULL;
}
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 JSBool
SendToGenerator(JSContext *cx, JSGeneratorOp op, JSObject *obj,
JSGenerator *gen, jsval arg)
{
JSStackFrame *fp;
JSArena *arena;
JSBool ok;
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->frame.fun));
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;
}
/* Extend the current stack pool with gen->arena. */
arena = cx->stackPool.current;
JS_ASSERT(!arena->next);
JS_ASSERT(!gen->arena.next);
JS_ASSERT(cx->stackPool.current != &gen->arena);
cx->stackPool.current = arena->next = &gen->arena;
/* Push gen->frame around the interpreter activation. */
fp = js_GetTopStackFrame(cx);
cx->fp = &gen->frame;
gen->frame.down = fp;
ok = js_Interpret(cx);
cx->fp = fp;
gen->frame.down = NULL;
/* Retract the stack pool and sanitize gen->arena. */
JS_ASSERT(!gen->arena.next);
JS_ASSERT(arena->next == &gen->arena);
JS_ASSERT(cx->stackPool.current == &gen->arena);
cx->stackPool.current = arena;
arena->next = NULL;
if (gen->frame.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);
gen->frame.flags &= ~JSFRAME_YIELDING;
gen->state = JSGEN_OPEN;
return JS_TRUE;
}
gen->frame.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 JSBool
CloseGenerator(JSContext *cx, JSObject *obj)
{
JSGenerator *gen;
JS_ASSERT(STOBJ_GET_CLASS(obj) == &js_GeneratorClass);
gen = (JSGenerator *) JS_GetPrivate(cx, obj);
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;
JSGenerator *gen;
jsval arg;
obj = JS_THIS_OBJECT(cx, vp);
if (!JS_InstanceOf(cx, obj, &js_GeneratorClass, vp + 2))
return JS_FALSE;
gen = (JSGenerator *) JS_GetPrivate(cx, obj);
if (gen == NULL) {
/* 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->frame.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_iterator_str, iterator_self, 0,JSPROP_ROPERM),
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, Iterator, 2,
NULL, iterator_methods, NULL, NULL);
if (!proto)
return NULL;
STOBJ_SET_SLOT(proto, JSSLOT_ITER_STATE, JSVAL_NULL);
#if JS_HAS_GENERATORS
/* Initialize the generator internals if configured. */
if (!JS_InitClass(cx, obj, NULL, &js_GeneratorClass, 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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