/js/lib/Socket.IO-node/support/expresso/deps/jscoverage/js/jsxml.cpp

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=4 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 SpiderMonkey E4X code, released August, 2004.
 *
 * 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 ***** */

#include "jsstddef.h"
#include "jsversion.h"

#if JS_HAS_XML_SUPPORT

#include <math.h>
#include <stdlib.h>
#include <string.h>
#include "jstypes.h"
#include "jsbit.h"
#include "jsprf.h"
#include "jsutil.h"
#include "jsapi.h"
#include "jsarray.h"
#include "jsatom.h"
#include "jsbool.h"
#include "jscntxt.h"
#include "jsfun.h"
#include "jsgc.h"
#include "jsinterp.h"
#include "jslock.h"
#include "jsnum.h"
#include "jsobj.h"
#include "jsopcode.h"
#include "jsparse.h"
#include "jsscan.h"
#include "jsscope.h"
#include "jsscript.h"
#include "jsstr.h"
#include "jsxml.h"
#include "jsstaticcheck.h"

#ifdef DEBUG
#include <string.h>     /* for #ifdef DEBUG memset calls */
#endif

/*
 * NOTES
 * - in the js shell, you must use the -x command line option, or call
 *   options('xml') before compiling anything that uses XML literals
 *
 * TODO
 * - XXXbe patrol
 * - Fuse objects and their JSXML* private data into single GC-things
 * - fix function::foo vs. x.(foo == 42) collision using proper namespacing
 * - fix the !TCF_HAS_DEFXMLNS optimization in js_FoldConstants
 * - JSCLASS_DOCUMENT_OBSERVER support -- live two-way binding to Gecko's DOM!
 * - JS_TypeOfValue sure could use a cleaner interface to "types"
 */

#ifdef XML_METERING
static struct {
    jsrefcount  qname;
    jsrefcount  xmlnamespace;
    jsrefcount  xml;
    jsrefcount  xmlobj;
} xml_stats;

#define METER(x)        JS_ATOMIC_INCREMENT(&(x))
#define UNMETER(x)      JS_ATOMIC_DECREMENT(&(x))
#else
#define METER(x)        /* nothing */
#define UNMETER(x)      /* nothing */
#endif

/*
 * Random utilities and global functions.
 */
const char js_isXMLName_str[]     = "isXMLName";
const char js_XMLList_str[]       = "XMLList";
const char js_localName_str[]     = "localName";
const char js_xml_parent_str[]    = "parent";
const char js_prefix_str[]        = "prefix";
const char js_toXMLString_str[]   = "toXMLString";
const char js_uri_str[]           = "uri";

const char js_amp_entity_str[]    = "&amp;";
const char js_gt_entity_str[]     = "&gt;";
const char js_lt_entity_str[]     = "&lt;";
const char js_quot_entity_str[]   = "&quot;";

#define IS_EMPTY(str) (JSSTRING_LENGTH(str) == 0)
#define IS_STAR(str)  (JSSTRING_LENGTH(str) == 1 && *JSSTRING_CHARS(str) == '*')
/* Slot indexes shared between Namespace and QName objects. */
const uint32 JSSLOT_PREFIX      = JSSLOT_PRIVATE;
const uint32 JSSLOT_URI         = JSSLOT_PRIVATE + 1;

/* Namespace-specific slot. */
const uint32 JSSLOT_DECLARED    = JSSLOT_PRIVATE + 2;

/* QName-specific slot. */
const uint32 JSSLOT_LOCAL_NAME  = JSSLOT_PRIVATE + 2;

const uint32 NAMESPACE_RESERVED_SLOTS = 3;
const uint32 QNAME_RESERVED_SLOTS = 3;

static JSBool
IsQNameClass(JSClass *clasp)
{
    return clasp == &js_QNameClass.base ||
           clasp == &js_AttributeNameClass ||
           clasp == &js_AnyNameClass;
}

static JSString *
GetSlotString(const JSObject *obj, uint32 slot)
{
    jsval v;

    JS_ASSERT(slot == JSSLOT_PREFIX ||
              slot == JSSLOT_URI ||
              slot == JSSLOT_LOCAL_NAME);
    JS_ASSERT(STOBJ_GET_CLASS(obj) == &js_NamespaceClass.base ||
              IsQNameClass(STOBJ_GET_CLASS(obj)));
    JS_ASSERT_IF(STOBJ_GET_CLASS(obj) == &js_NamespaceClass.base,
                 slot != JSSLOT_LOCAL_NAME);

    v = obj->fslots[slot];
    if (JSVAL_IS_VOID(v))
        return NULL;
    JS_ASSERT(JSVAL_IS_STRING(v));
    return JSVAL_TO_STRING(v);
}

static JS_INLINE JSString *
GetPrefix(const JSObject *obj)
{
    return GetSlotString(obj, JSSLOT_PREFIX);
}

static JSString *
GetURI(const JSObject *obj)
{
    return GetSlotString(obj, JSSLOT_URI);
}

static JSString *
GetLocalName(const JSObject *obj)
{
    return GetSlotString(obj, JSSLOT_LOCAL_NAME);
}

static JSBool
IsDeclared(const JSObject *obj)
{
    jsval v;

    JS_ASSERT(STOBJ_GET_CLASS(obj) == &js_NamespaceClass.base);
    v = obj->fslots[JSSLOT_DECLARED];
    JS_ASSERT(JSVAL_IS_VOID(v) || v == JSVAL_TRUE);
    return v == JSVAL_TRUE;
}

static JSBool
xml_isXMLName(JSContext *cx, JSObject *obj, uintN argc, jsval *argv,
              jsval *rval)
{
    *rval = BOOLEAN_TO_JSVAL(js_IsXMLName(cx, argv[0]));
    return JS_TRUE;
}

/*
 * Namespace class and library functions.
 */
enum namespace_tinyid {
    NAMESPACE_PREFIX = -1,
    NAMESPACE_URI = -2
};

static JSBool
namespace_getProperty(JSContext *cx, JSObject *obj, jsval id, jsval *vp)
{
    if (!JSVAL_IS_INT(id))
        return JS_TRUE;

    if (STOBJ_GET_CLASS(obj) != &js_NamespaceClass.base)
        return JS_TRUE;

    switch (JSVAL_TO_INT(id)) {
      case NAMESPACE_PREFIX:
        *vp = obj->fslots[JSSLOT_PREFIX];
        break;
      case NAMESPACE_URI:
        *vp = obj->fslots[JSSLOT_URI];
        break;
    }
    return JS_TRUE;
}

static void
namespace_finalize(JSContext *cx, JSObject *obj)
{
    if (cx->runtime->functionNamespaceObject == obj)
        cx->runtime->functionNamespaceObject = NULL;
}

static JSBool
namespace_equality(JSContext *cx, JSObject *obj, jsval v, JSBool *bp)
{
    JSObject *obj2;

    JS_ASSERT(JSVAL_IS_OBJECT(v));
    obj2 = JSVAL_TO_OBJECT(v);
    *bp = (!obj2 || OBJ_GET_CLASS(cx, obj2) != &js_NamespaceClass.base)
          ? JS_FALSE
          : js_EqualStrings(GetURI(obj), GetURI(obj2));
    return JS_TRUE;
}

JS_FRIEND_DATA(JSExtendedClass) js_NamespaceClass = {
  { "Namespace",
    JSCLASS_CONSTRUCT_PROTOTYPE | JSCLASS_IS_EXTENDED |
    JSCLASS_HAS_RESERVED_SLOTS(NAMESPACE_RESERVED_SLOTS) |
    JSCLASS_MARK_IS_TRACE | JSCLASS_HAS_CACHED_PROTO(JSProto_Namespace),
    JS_PropertyStub,   JS_PropertyStub,   namespace_getProperty, NULL,
    JS_EnumerateStub,  JS_ResolveStub,    JS_ConvertStub,    namespace_finalize,
    NULL,              NULL,              NULL,              NULL,
    NULL,              NULL,              NULL,              NULL },
    namespace_equality,NULL,              NULL,              NULL,
    NULL,              NULL,              NULL,              NULL
};

#define NAMESPACE_ATTRS                                                       \
    (JSPROP_ENUMERATE | JSPROP_READONLY | JSPROP_PERMANENT | JSPROP_SHARED)

static JSPropertySpec namespace_props[] = {
    {js_prefix_str,    NAMESPACE_PREFIX,  NAMESPACE_ATTRS,   0, 0},
    {js_uri_str,       NAMESPACE_URI,     NAMESPACE_ATTRS,   0, 0},
    {0,0,0,0,0}
};

static JSBool
namespace_toString(JSContext *cx, uintN argc, jsval *vp)
{
    JSObject *obj;

    obj = JS_THIS_OBJECT(cx, vp);
    if (!JS_InstanceOf(cx, obj, &js_NamespaceClass.base, vp))
        return JS_FALSE;
    *vp = obj->fslots[JSSLOT_URI];
    return JS_TRUE;
}

static JSFunctionSpec namespace_methods[] = {
    JS_FN(js_toString_str,  namespace_toString,        0,0),
    JS_FS_END
};

static JSObject *
NewXMLNamespace(JSContext *cx, JSString *prefix, JSString *uri, JSBool declared)
{
    JSObject *obj;

    obj = js_NewObject(cx, &js_NamespaceClass.base, NULL, NULL, 0);
    if (!obj)
        return JS_FALSE;
    JS_ASSERT(JSVAL_IS_VOID(obj->fslots[JSSLOT_PREFIX]));
    JS_ASSERT(JSVAL_IS_VOID(obj->fslots[JSSLOT_URI]));
    JS_ASSERT(JSVAL_IS_VOID(obj->fslots[JSSLOT_DECLARED]));
    if (prefix)
        obj->fslots[JSSLOT_PREFIX] = STRING_TO_JSVAL(prefix);
    if (uri)
        obj->fslots[JSSLOT_URI] = STRING_TO_JSVAL(uri);
    if (declared)
        obj->fslots[JSSLOT_DECLARED] = JSVAL_TRUE;
    METER(xml_stats.xmlnamespace);
    return obj;
}

/*
 * QName class and library functions.
 */
enum qname_tinyid {
    QNAME_URI = -1,
    QNAME_LOCALNAME = -2
};

static JSBool
qname_getProperty(JSContext *cx, JSObject *obj, jsval id, jsval *vp)
{
    if (!JSVAL_IS_INT(id))
        return JS_TRUE;

    if (STOBJ_GET_CLASS(obj) != &js_QNameClass.base)
        return JS_TRUE;

    switch (JSVAL_TO_INT(id)) {
      case QNAME_URI:
        *vp = obj->fslots[JSSLOT_URI];
        if (*vp == JSVAL_VOID)
            *vp = JSVAL_NULL;
        break;
      case QNAME_LOCALNAME:
        *vp = obj->fslots[JSSLOT_LOCAL_NAME];
        break;
    }
    return JS_TRUE;
}

static void
anyname_finalize(JSContext* cx, JSObject* obj)
{
    /* Make sure the next call to js_GetAnyName doesn't try to use obj. */
    if (cx->runtime->anynameObject == obj)
        cx->runtime->anynameObject = NULL;
}

static JSBool
qname_identity(JSObject *qna, JSObject *qnb)
{
    JSString *uri1 = GetURI(qna);
    JSString *uri2 = GetURI(qnb);

    if (!uri1 ^ !uri2)
        return JS_FALSE;
    if (uri1 && !js_EqualStrings(uri1, uri2))
        return JS_FALSE;
    return js_EqualStrings(GetLocalName(qna), GetLocalName(qnb));
}

static JSBool
qname_equality(JSContext *cx, JSObject *qn, jsval v, JSBool *bp)
{
    JSObject *obj2;

    JS_ASSERT(JSVAL_IS_OBJECT(v));
    obj2 = JSVAL_TO_OBJECT(v);
    *bp = (!obj2 || OBJ_GET_CLASS(cx, obj2) != &js_QNameClass.base)
          ? JS_FALSE
          : qname_identity(qn, obj2);
    return JS_TRUE;
}

JS_FRIEND_DATA(JSExtendedClass) js_QNameClass = {
  { "QName",
    JSCLASS_CONSTRUCT_PROTOTYPE | JSCLASS_IS_EXTENDED |
    JSCLASS_HAS_RESERVED_SLOTS(QNAME_RESERVED_SLOTS) |
    JSCLASS_MARK_IS_TRACE | JSCLASS_HAS_CACHED_PROTO(JSProto_QName),
    JS_PropertyStub,   JS_PropertyStub,   qname_getProperty, NULL,
    JS_EnumerateStub,  JS_ResolveStub,    JS_ConvertStub,    JS_FinalizeStub,
    NULL,              NULL,              NULL,              NULL,
    NULL,              NULL,              NULL,              NULL },
    qname_equality,    NULL,              NULL,              NULL,
    NULL,              NULL,              NULL,              NULL
};

/*
 * Classes for the ECMA-357-internal types AttributeName and AnyName, which
 * are like QName, except that they have no property getters.  They share the
 * qname_toString method, and therefore are exposed as constructable objects
 * in this implementation.
 */
JS_FRIEND_DATA(JSClass) js_AttributeNameClass = {
    js_AttributeName_str,
    JSCLASS_CONSTRUCT_PROTOTYPE |
    JSCLASS_HAS_RESERVED_SLOTS(QNAME_RESERVED_SLOTS) |
    JSCLASS_MARK_IS_TRACE | JSCLASS_HAS_CACHED_PROTO(JSProto_AttributeName),
    JS_PropertyStub,   JS_PropertyStub,   JS_PropertyStub,   JS_PropertyStub,
    JS_EnumerateStub,  JS_ResolveStub,    JS_ConvertStub,    JS_FinalizeStub,
    NULL,              NULL,              NULL,              NULL,
    NULL,              NULL,              NULL,              NULL
};

JS_FRIEND_DATA(JSClass) js_AnyNameClass = {
    js_AnyName_str,
    JSCLASS_CONSTRUCT_PROTOTYPE |
    JSCLASS_HAS_RESERVED_SLOTS(QNAME_RESERVED_SLOTS) |
    JSCLASS_MARK_IS_TRACE | JSCLASS_HAS_CACHED_PROTO(JSProto_AnyName),
    JS_PropertyStub,   JS_PropertyStub,   JS_PropertyStub,   JS_PropertyStub,
    JS_EnumerateStub,  JS_ResolveStub,    JS_ConvertStub,    anyname_finalize,
    NULL,              NULL,              NULL,              NULL,
    NULL,              NULL,              NULL,              NULL
};

#define QNAME_ATTRS                                                           \
    (JSPROP_ENUMERATE | JSPROP_READONLY | JSPROP_PERMANENT | JSPROP_SHARED)

static JSPropertySpec qname_props[] = {
    {js_uri_str,       QNAME_URI,         QNAME_ATTRS,       0, 0},
    {js_localName_str, QNAME_LOCALNAME,   QNAME_ATTRS,       0, 0},
    {0,0,0,0,0}
};

static JSBool
qname_toString(JSContext *cx, uintN argc, jsval *vp)
{
    JSObject *obj;
    JSClass *clasp;
    JSString *uri, *str, *qualstr;
    size_t length;
    jschar *chars;

    obj = JS_THIS_OBJECT(cx, vp);
    if (!obj)
        return JS_FALSE;
    clasp = OBJ_GET_CLASS(cx, obj);
    if (clasp != &js_AttributeNameClass &&
        clasp != &js_AnyNameClass &&
        !JS_InstanceOf(cx, obj, &js_QNameClass.base, vp + 2)) {
            return JS_FALSE;
    }

    uri = GetURI(obj);
    if (!uri) {
        /* No uri means wildcard qualifier. */
        str = ATOM_TO_STRING(cx->runtime->atomState.starQualifierAtom);
    } else if (IS_EMPTY(uri)) {
        /* Empty string for uri means localName is in no namespace. */
        str = cx->runtime->emptyString;
    } else {
        qualstr = ATOM_TO_STRING(cx->runtime->atomState.qualifierAtom);
        str = js_ConcatStrings(cx, uri, qualstr);
        if (!str)
            return JS_FALSE;
    }
    str = js_ConcatStrings(cx, str, GetLocalName(obj));
    if (!str)
        return JS_FALSE;

    if (str && clasp == &js_AttributeNameClass) {
        length = JSSTRING_LENGTH(str);
        chars = (jschar *) JS_malloc(cx, (length + 2) * sizeof(jschar));
        if (!chars)
            return JS_FALSE;
        *chars = '@';
        js_strncpy(chars + 1, JSSTRING_CHARS(str), length);
        chars[++length] = 0;
        str = js_NewString(cx, chars, length);
        if (!str) {
            JS_free(cx, chars);
            return JS_FALSE;
        }
    }

    *vp = STRING_TO_JSVAL(str);
    return JS_TRUE;
}

static JSFunctionSpec qname_methods[] = {
    JS_FN(js_toString_str,  qname_toString,    0,0),
    JS_FS_END
};


static void
InitXMLQName(JSObject *obj, JSString *uri, JSString *prefix,
             JSString *localName)
{
    JS_ASSERT(JSVAL_IS_VOID(obj->fslots[JSSLOT_PREFIX]));
    JS_ASSERT(JSVAL_IS_VOID(obj->fslots[JSSLOT_URI]));
    JS_ASSERT(JSVAL_IS_VOID(obj->fslots[JSSLOT_LOCAL_NAME]));
    if (uri)
        obj->fslots[JSSLOT_URI] = STRING_TO_JSVAL(uri);
    if (prefix)
        obj->fslots[JSSLOT_PREFIX] = STRING_TO_JSVAL(prefix);
    if (localName)
        obj->fslots[JSSLOT_LOCAL_NAME] = STRING_TO_JSVAL(localName);
}

static JSObject *
NewXMLQName(JSContext *cx, JSString *uri, JSString *prefix, JSString *localName,
            JSClass *clasp = &js_QNameClass.base)
{
    JSObject *obj;

    JS_ASSERT(IsQNameClass(clasp));
    obj = js_NewObject(cx, clasp, NULL, NULL, 0);
    if (!obj)
        return NULL;
    InitXMLQName(obj, uri, prefix, localName);
    METER(xml_stats.qname);
    return obj;
}

JSObject *
js_ConstructXMLQNameObject(JSContext *cx, jsval nsval, jsval lnval)
{
    jsval argv[2];

    /*
     * ECMA-357 11.1.2,
     * The _QualifiedIdentifier : PropertySelector :: PropertySelector_
     * production, step 2.
     */
    if (!JSVAL_IS_PRIMITIVE(nsval) &&
        OBJ_GET_CLASS(cx, JSVAL_TO_OBJECT(nsval)) == &js_AnyNameClass) {
        nsval = JSVAL_NULL;
    }

    argv[0] = nsval;
    argv[1] = lnval;
    return js_ConstructObject(cx, &js_QNameClass.base, NULL, NULL, 2, argv);
}

static JSBool
IsXMLName(const jschar *cp, size_t n)
{
    JSBool rv;
    jschar c;

    rv = JS_FALSE;
    if (n != 0 && JS_ISXMLNSSTART(*cp)) {
        while (--n != 0) {
            c = *++cp;
            if (!JS_ISXMLNS(c))
                return rv;
        }
        rv = JS_TRUE;
    }
    return rv;
}

JSBool
js_IsXMLName(JSContext *cx, jsval v)
{
    JSString *name;
    JSErrorReporter older;

    /*
     * Inline specialization of the QName constructor called with v passed as
     * the only argument, to compute the localName for the constructed qname,
     * without actually allocating the object or computing its uri and prefix.
     * See ECMA-357 13.1.2.1 step 1 and 13.3.2.
     */
    if (!JSVAL_IS_PRIMITIVE(v) &&
        IsQNameClass(OBJ_GET_CLASS(cx, JSVAL_TO_OBJECT(v)))) {
        name = GetLocalName(JSVAL_TO_OBJECT(v));
    } else {
        older = JS_SetErrorReporter(cx, NULL);
        name = js_ValueToString(cx, v);
        JS_SetErrorReporter(cx, older);
        if (!name) {
            JS_ClearPendingException(cx);
            return JS_FALSE;
        }
    }

    return IsXMLName(JSSTRING_CHARS(name), JSSTRING_LENGTH(name));
}

/*
 * When argc is -1, it indicates argv is empty but the code should behave as
 * if argc is 1 and argv[0] is JSVAL_VOID.
 */
static JSBool
NamespaceHelper(JSContext *cx, JSObject *obj, intN argc, jsval *argv,
                jsval *rval)
{
    jsval urival, prefixval;
    JSObject *uriobj;
    JSBool isNamespace, isQName;
    JSClass *clasp;
    JSString *empty, *uri, *prefix;

    isNamespace = isQName = JS_FALSE;
#ifdef __GNUC__         /* suppress bogus gcc warnings */
    uriobj = NULL;
#endif
    if (argc <= 0) {
        urival = JSVAL_VOID;
    } else {
        urival = argv[argc > 1];
        if (!JSVAL_IS_PRIMITIVE(urival)) {
            uriobj = JSVAL_TO_OBJECT(urival);
            clasp = OBJ_GET_CLASS(cx, uriobj);
            isNamespace = (clasp == &js_NamespaceClass.base);
            isQName = (clasp == &js_QNameClass.base);
        }
    }

    if (!obj) {
        /* Namespace called as function. */
        if (argc == 1 && isNamespace) {
            /* Namespace called with one Namespace argument is identity. */
            *rval = urival;
            return JS_TRUE;
        }

        obj = js_NewObject(cx, &js_NamespaceClass.base, NULL, NULL, 0);
        if (!obj)
            return JS_FALSE;
        *rval = OBJECT_TO_JSVAL(obj);
    }
    METER(xml_stats.xmlnamespace);

    empty = cx->runtime->emptyString;
    obj->fslots[JSSLOT_PREFIX] = STRING_TO_JSVAL(empty);
    obj->fslots[JSSLOT_URI] = STRING_TO_JSVAL(empty);

    if (argc == 1 || argc == -1) {
        if (isNamespace) {
            obj->fslots[JSSLOT_URI] = uriobj->fslots[JSSLOT_URI];
            obj->fslots[JSSLOT_PREFIX] = uriobj->fslots[JSSLOT_PREFIX];
        } else if (isQName && (uri = GetURI(uriobj))) {
            obj->fslots[JSSLOT_URI] = STRING_TO_JSVAL(uri);
            obj->fslots[JSSLOT_PREFIX] = uriobj->fslots[JSSLOT_PREFIX];
        } else {
            uri = js_ValueToString(cx, urival);
            if (!uri)
                return JS_FALSE;
            obj->fslots[JSSLOT_URI] = STRING_TO_JSVAL(uri);
            if (!IS_EMPTY(uri))
                obj->fslots[JSSLOT_PREFIX] = JSVAL_VOID;
        }
    } else if (argc == 2) {
        if (!isQName || !(uri = GetURI(uriobj))) {
            uri = js_ValueToString(cx, urival);
            if (!uri)
                return JS_FALSE;
        }
        obj->fslots[JSSLOT_URI] = STRING_TO_JSVAL(uri);

        prefixval = argv[0];
        if (IS_EMPTY(uri)) {
            if (!JSVAL_IS_VOID(prefixval)) {
                prefix = js_ValueToString(cx, prefixval);
                if (!prefix)
                    return JS_FALSE;
                if (!IS_EMPTY(prefix)) {
                    JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL,
                                         JSMSG_BAD_XML_NAMESPACE,
                                         js_ValueToPrintableString(cx,
                                             STRING_TO_JSVAL(prefix)));
                    return JS_FALSE;
                }
            }
        } else if (JSVAL_IS_VOID(prefixval) || !js_IsXMLName(cx, prefixval)) {
            obj->fslots[JSSLOT_PREFIX] = JSVAL_VOID;
        } else {
            prefix = js_ValueToString(cx, prefixval);
            if (!prefix)
                return JS_FALSE;
            obj->fslots[JSSLOT_PREFIX] = STRING_TO_JSVAL(prefix);
        }
    }

    return JS_TRUE;
}

static JSBool
Namespace(JSContext *cx, JSObject *obj, uintN argc, jsval *argv, jsval *rval)
{
    return NamespaceHelper(cx,
                           (cx->fp->flags & JSFRAME_CONSTRUCTING) ? obj : NULL,
                           argc, argv, rval);
}

/*
 * When argc is -1, it indicates argv is empty but the code should behave as
 * if argc is 1 and argv[0] is JSVAL_VOID.
 */
static JSBool
QNameHelper(JSContext *cx, JSObject *obj, JSClass *clasp, intN argc,
            jsval *argv, jsval *rval)
{
    jsval nameval, nsval;
    JSBool isQName, isNamespace;
    JSObject *qn;
    JSString *uri, *prefix, *name;
    JSObject *obj2;

    JS_ASSERT(clasp == &js_QNameClass.base ||
              clasp == &js_AttributeNameClass);
    if (argc <= 0) {
        nameval = JSVAL_VOID;
        isQName = JS_FALSE;
    } else {
        nameval = argv[argc > 1];
        isQName =
            !JSVAL_IS_PRIMITIVE(nameval) &&
            OBJ_GET_CLASS(cx, JSVAL_TO_OBJECT(nameval)) == &js_QNameClass.base;
    }

    if (!obj) {
        /* QName called as function. */
        if (argc == 1 && isQName) {
            /* QName called with one QName argument is identity. */
            *rval = nameval;
            return JS_TRUE;
        }

        /*
         * Create and return a new QName or AttributeName object exactly as if
         * constructed.
         */
        obj = js_NewObject(cx, clasp, NULL, NULL, 0);
        if (!obj)
            return JS_FALSE;
        *rval = OBJECT_TO_JSVAL(obj);
    }
    METER(xml_stats.qname);

    if (isQName) {
        /* If namespace is not specified and name is a QName, clone it. */
        qn = JSVAL_TO_OBJECT(nameval);
        if (argc == 1) {
            uri = GetURI(qn);
            prefix = GetPrefix(qn);
            name = GetLocalName(qn);
            goto out;
        }

        /* Namespace and qname were passed -- use the qname's localName. */
        nameval = qn->fslots[JSSLOT_LOCAL_NAME];
    }

    if (argc == 0) {
        name = cx->runtime->emptyString;
    } else if (argc < 0) {
        name = ATOM_TO_STRING(cx->runtime->atomState.typeAtoms[JSTYPE_VOID]);
    } else {
        name = js_ValueToString(cx, nameval);
        if (!name)
            return JS_FALSE;
        argv[argc > 1] = STRING_TO_JSVAL(name);
    }

    if (argc > 1 && !JSVAL_IS_VOID(argv[0])) {
        nsval = argv[0];
    } else if (IS_STAR(name)) {
        nsval = JSVAL_NULL;
    } else {
        if (!js_GetDefaultXMLNamespace(cx, &nsval))
            return JS_FALSE;
        JS_ASSERT(!JSVAL_IS_PRIMITIVE(nsval));
        JS_ASSERT(OBJ_GET_CLASS(cx, JSVAL_TO_OBJECT(nsval)) ==
                  &js_NamespaceClass.base);
    }

    if (JSVAL_IS_NULL(nsval)) {
        /* NULL prefix represents *undefined* in ECMA-357 13.3.2 5(a). */
        uri = prefix = NULL;
    } else {
        /*
         * Inline specialization of the Namespace constructor called with
         * nsval passed as the only argument, to compute the uri and prefix
         * for the constructed namespace, without actually allocating the
         * object or computing other members.  See ECMA-357 13.3.2 6(a) and
         * 13.2.2.
         */
        isNamespace = isQName = JS_FALSE;
        if (!JSVAL_IS_PRIMITIVE(nsval)) {
            obj2 = JSVAL_TO_OBJECT(nsval);
            clasp = OBJ_GET_CLASS(cx, obj2);
            isNamespace = (clasp == &js_NamespaceClass.base);
            isQName = (clasp == &js_QNameClass.base);
        }
#ifdef __GNUC__         /* suppress bogus gcc warnings */
        else obj2 = NULL;
#endif

        if (isNamespace) {
            uri = GetURI(obj2);
            prefix = GetPrefix(obj2);
        } else if (isQName && (uri = GetURI(obj2))) {
            JS_ASSERT(argc > 1);
            prefix = GetPrefix(obj2);
        } else {
            JS_ASSERT(argc > 1);
            uri = js_ValueToString(cx, nsval);
            if (!uri)
                return JS_FALSE;
            argv[0] = STRING_TO_JSVAL(uri);     /* local root */

            /* NULL here represents *undefined* in ECMA-357 13.2.2 3(c)iii. */
            prefix = IS_EMPTY(uri) ? cx->runtime->emptyString : NULL;
        }
    }

out:
    InitXMLQName(obj, uri, prefix, name);
    return JS_TRUE;
}

static JSBool
QName(JSContext *cx, JSObject *obj, uintN argc, jsval *argv, jsval *rval)
{
    return QNameHelper(cx, (cx->fp->flags & JSFRAME_CONSTRUCTING) ? obj : NULL,
                       &js_QNameClass.base, argc, argv, rval);
}

static JSBool
AttributeName(JSContext *cx, JSObject *obj, uintN argc, jsval *argv,
              jsval *rval)
{
    return QNameHelper(cx, (cx->fp->flags & JSFRAME_CONSTRUCTING) ? obj : NULL,
                       &js_AttributeNameClass, argc, argv, rval);
}

/*
 * XMLArray library functions.
 */
static JSBool
namespace_identity(const void *a, const void *b)
{
    const JSObject *nsa = (const JSObject *) a;
    const JSObject *nsb = (const JSObject *) b;
    JSString *prefixa = GetPrefix(nsa);
    JSString *prefixb = GetPrefix(nsb);

    if (prefixa && prefixb) {
        if (!js_EqualStrings(prefixa, prefixb))
            return JS_FALSE;
    } else {
        if (prefixa || prefixb)
            return JS_FALSE;
    }
    return js_EqualStrings(GetURI(nsa), GetURI(nsb));
}

static JSBool
attr_identity(const void *a, const void *b)
{
    const JSXML *xmla = (const JSXML *) a;
    const JSXML *xmlb = (const JSXML *) b;

    return qname_identity(xmla->name, xmlb->name);
}

static void
XMLArrayCursorInit(JSXMLArrayCursor *cursor, JSXMLArray *array)
{
    JSXMLArrayCursor *next;

    cursor->array = array;
    cursor->index = 0;
    next = cursor->next = array->cursors;
    if (next)
        next->prevp = &cursor->next;
    cursor->prevp = &array->cursors;
    array->cursors = cursor;
    cursor->root = NULL;
}

static void
XMLArrayCursorFinish(JSXMLArrayCursor *cursor)
{
    JSXMLArrayCursor *next;

    if (!cursor->array)
        return;
    next = cursor->next;
    if (next)
        next->prevp = cursor->prevp;
    *cursor->prevp = next;
    cursor->array = NULL;
}

static void *
XMLArrayCursorNext(JSXMLArrayCursor *cursor)
{
    JSXMLArray *array;

    array = cursor->array;
    if (!array || cursor->index >= array->length)
        return NULL;
    return cursor->root = array->vector[cursor->index++];
}

static void *
XMLArrayCursorItem(JSXMLArrayCursor *cursor)
{
    JSXMLArray *array;

    array = cursor->array;
    if (!array || cursor->index >= array->length)
        return NULL;
    return cursor->root = array->vector[cursor->index];
}

static void
XMLArrayCursorTrace(JSTracer *trc, JSXMLArrayCursor *cursor)
{
    void *root;
#ifdef DEBUG
    size_t index = 0;
#endif

    for (; cursor; cursor = cursor->next) {
        root = cursor->root;
        JS_SET_TRACING_INDEX(trc, "cursor_root", index++);
        js_CallValueTracerIfGCThing(trc, (jsval)root);
    }
}

/* NB: called with null cx from the GC, via xml_trace => XMLArrayTrim. */
static JSBool
XMLArraySetCapacity(JSContext *cx, JSXMLArray *array, uint32 capacity)
{
    void **vector;

    if (capacity == 0) {
        /* We could let realloc(p, 0) free this, but purify gets confused. */
        if (array->vector)
            free(array->vector);
        vector = NULL;
    } else {
        if (
#if JS_BITS_PER_WORD == 32
            (size_t)capacity > ~(size_t)0 / sizeof(void *) ||
#endif
            !(vector = (void **)
                       realloc(array->vector, capacity * sizeof(void *)))) {
            if (cx)
                JS_ReportOutOfMemory(cx);
            return JS_FALSE;
        }
    }
    array->capacity = JSXML_PRESET_CAPACITY | capacity;
    array->vector = vector;
    return JS_TRUE;
}

static void
XMLArrayTrim(JSXMLArray *array)
{
    if (array->capacity & JSXML_PRESET_CAPACITY)
        return;
    if (array->length < array->capacity)
        XMLArraySetCapacity(NULL, array, array->length);
}

static JSBool
XMLArrayInit(JSContext *cx, JSXMLArray *array, uint32 capacity)
{
    array->length = array->capacity = 0;
    array->vector = NULL;
    array->cursors = NULL;
    return capacity == 0 || XMLArraySetCapacity(cx, array, capacity);
}

static void
XMLArrayFinish(JSContext *cx, JSXMLArray *array)
{
    JSXMLArrayCursor *cursor;

    JS_free(cx, array->vector);

    while ((cursor = array->cursors) != NULL)
        XMLArrayCursorFinish(cursor);

#ifdef DEBUG
    memset(array, 0xd5, sizeof *array);
#endif
}

#define XML_NOT_FOUND   ((uint32) -1)

static uint32
XMLArrayFindMember(const JSXMLArray *array, void *elt, JSIdentityOp identity)
{
    void **vector;
    uint32 i, n;

    /* The identity op must not reallocate array->vector. */
    vector = array->vector;
    if (identity) {
        for (i = 0, n = array->length; i < n; i++) {
            if (identity(vector[i], elt))
                return i;
        }
    } else {
        for (i = 0, n = array->length; i < n; i++) {
            if (vector[i] == elt)
                return i;
        }
    }
    return XML_NOT_FOUND;
}

/*
 * Grow array vector capacity by powers of two to LINEAR_THRESHOLD, and after
 * that, grow by LINEAR_INCREMENT.  Both must be powers of two, and threshold
 * should be greater than increment.
 */
#define LINEAR_THRESHOLD        256
#define LINEAR_INCREMENT        32

static JSBool
XMLArrayAddMember(JSContext *cx, JSXMLArray *array, uint32 index, void *elt)
{
    uint32 capacity, i;
    int log2;
    void **vector;

    if (index >= array->length) {
        if (index >= JSXML_CAPACITY(array)) {
            /* Arrange to clear JSXML_PRESET_CAPACITY from array->capacity. */
            capacity = index + 1;
            if (index >= LINEAR_THRESHOLD) {
                capacity = JS_ROUNDUP(capacity, LINEAR_INCREMENT);
            } else {
                JS_CEILING_LOG2(log2, capacity);
                capacity = JS_BIT(log2);
            }
            if (
#if JS_BITS_PER_WORD == 32
                (size_t)capacity > ~(size_t)0 / sizeof(void *) ||
#endif
                !(vector = (void **)
                           realloc(array->vector, capacity * sizeof(void *)))) {
                JS_ReportOutOfMemory(cx);
                return JS_FALSE;
            }
            array->capacity = capacity;
            array->vector = vector;
            for (i = array->length; i < index; i++)
                vector[i] = NULL;
        }
        array->length = index + 1;
    }

    array->vector[index] = elt;
    return JS_TRUE;
}

static JSBool
XMLArrayInsert(JSContext *cx, JSXMLArray *array, uint32 i, uint32 n)
{
    uint32 j;
    JSXMLArrayCursor *cursor;

    j = array->length;
    JS_ASSERT(i <= j);
    if (!XMLArraySetCapacity(cx, array, j + n))
        return JS_FALSE;

    array->length = j + n;
    JS_ASSERT(n != (uint32)-1);
    while (j != i) {
        --j;
        array->vector[j + n] = array->vector[j];
    }

    for (cursor = array->cursors; cursor; cursor = cursor->next) {
        if (cursor->index > i)
            cursor->index += n;
    }
    return JS_TRUE;
}

static void *
XMLArrayDelete(JSContext *cx, JSXMLArray *array, uint32 index, JSBool compress)
{
    uint32 length;
    void **vector, *elt;
    JSXMLArrayCursor *cursor;

    length = array->length;
    if (index >= length)
        return NULL;

    vector = array->vector;
    elt = vector[index];
    if (compress) {
        while (++index < length)
            vector[index-1] = vector[index];
        array->length = length - 1;
        array->capacity = JSXML_CAPACITY(array);
    } else {
        vector[index] = NULL;
    }

    for (cursor = array->cursors; cursor; cursor = cursor->next) {
        if (cursor->index > index)
            --cursor->index;
    }
    return elt;
}

static void
XMLArrayTruncate(JSContext *cx, JSXMLArray *array, uint32 length)
{
    void **vector;

    JS_ASSERT(!array->cursors);
    if (length >= array->length)
        return;

    if (length == 0) {
        if (array->vector)
            free(array->vector);
        vector = NULL;
    } else {
        vector = (void **) realloc(array->vector, length * sizeof(void *));
        if (!vector)
            return;
    }

    if (array->length > length)
        array->length = length;
    array->capacity = length;
    array->vector = vector;
}

#define XMLARRAY_FIND_MEMBER(a,e,f) XMLArrayFindMember(a, (void *)(e), f)
#define XMLARRAY_HAS_MEMBER(a,e,f)  (XMLArrayFindMember(a, (void *)(e), f) != \
                                     XML_NOT_FOUND)
#define XMLARRAY_MEMBER(a,i,t)      (((i) < (a)->length)                      \
                                     ? (t *) (a)->vector[i]                   \
                                     : NULL)
#define XMLARRAY_SET_MEMBER(a,i,e)  JS_BEGIN_MACRO                            \
                                        if ((a)->length <= (i))               \
                                            (a)->length = (i) + 1;            \
                                        ((a)->vector[i] = (void *)(e));       \
                                    JS_END_MACRO
#define XMLARRAY_ADD_MEMBER(x,a,i,e)XMLArrayAddMember(x, a, i, (void *)(e))
#define XMLARRAY_INSERT(x,a,i,n)    XMLArrayInsert(x, a, i, n)
#define XMLARRAY_APPEND(x,a,e)      XMLARRAY_ADD_MEMBER(x, a, (a)->length, (e))
#define XMLARRAY_DELETE(x,a,i,c,t)  ((t *) XMLArrayDelete(x, a, i, c))
#define XMLARRAY_TRUNCATE(x,a,n)    XMLArrayTruncate(x, a, n)

/*
 * Define XML setting property strings and constants early, so everyone can
 * use the same names and their magic numbers (tinyids, flags).
 */
static const char js_ignoreComments_str[]   = "ignoreComments";
static const char js_ignoreProcessingInstructions_str[]
                                            = "ignoreProcessingInstructions";
static const char js_ignoreWhitespace_str[] = "ignoreWhitespace";
static const char js_prettyPrinting_str[]   = "prettyPrinting";
static const char js_prettyIndent_str[]     = "prettyIndent";

/*
 * NB: These XML static property tinyids must
 * (a) not collide with the generic negative tinyids at the top of jsfun.c;
 * (b) index their corresponding xml_static_props array elements.
 * Don't change 'em!
 */
enum xml_static_tinyid {
    XML_IGNORE_COMMENTS,
    XML_IGNORE_PROCESSING_INSTRUCTIONS,
    XML_IGNORE_WHITESPACE,
    XML_PRETTY_PRINTING,
    XML_PRETTY_INDENT
};

static JSBool
xml_setting_getter(JSContext *cx, JSObject *obj, jsval id, jsval *vp)
{
    return JS_TRUE;
}

static JSBool
xml_setting_setter(JSContext *cx, JSObject *obj, jsval id, jsval *vp)
{
    uint8 flag;

    JS_ASSERT(JSVAL_IS_INT(id));

    flag = JS_BIT(JSVAL_TO_INT(id));
    if (js_ValueToBoolean(*vp))
        cx->xmlSettingFlags |= flag;
    else
        cx->xmlSettingFlags &= ~flag;
    return JS_TRUE;
}

static JSPropertySpec xml_static_props[] = {
    {js_ignoreComments_str,     XML_IGNORE_COMMENTS,   JSPROP_PERMANENT,
                                xml_setting_getter, xml_setting_setter},
    {js_ignoreProcessingInstructions_str,
                   XML_IGNORE_PROCESSING_INSTRUCTIONS, JSPROP_PERMANENT,
                                xml_setting_getter, xml_setting_setter},
    {js_ignoreWhitespace_str,   XML_IGNORE_WHITESPACE, JSPROP_PERMANENT,
                                xml_setting_getter, xml_setting_setter},
    {js_prettyPrinting_str,     XML_PRETTY_PRINTING,   JSPROP_PERMANENT,
                                xml_setting_getter, xml_setting_setter},
    {js_prettyIndent_str,       XML_PRETTY_INDENT,     JSPROP_PERMANENT,
                                xml_setting_getter, NULL},
    {0,0,0,0,0}
};

/* Derive cx->xmlSettingFlags bits from xml_static_props tinyids. */
#define XSF_IGNORE_COMMENTS     JS_BIT(XML_IGNORE_COMMENTS)
#define XSF_IGNORE_PROCESSING_INSTRUCTIONS                                    \
                                JS_BIT(XML_IGNORE_PROCESSING_INSTRUCTIONS)
#define XSF_IGNORE_WHITESPACE   JS_BIT(XML_IGNORE_WHITESPACE)
#define XSF_PRETTY_PRINTING     JS_BIT(XML_PRETTY_PRINTING)
#define XSF_CACHE_VALID         JS_BIT(XML_PRETTY_INDENT)

/*
 * Extra, unrelated but necessarily disjoint flag used by ParseNodeToXML.
 * This flag means a couple of things:
 *
 * - The top JSXML created for a parse tree must have an object owning it.
 *
 * - That the default namespace normally inherited from the temporary
 *   <parent xmlns='...'> tag that wraps a runtime-concatenated XML source
 *   string must, in the case of a precompiled XML object tree, inherit via
 *   ad-hoc code in ParseNodeToXML.
 *
 * Because of the second purpose, we name this flag XSF_PRECOMPILED_ROOT.
 */
#define XSF_PRECOMPILED_ROOT    (XSF_CACHE_VALID << 1)

/* Macros for special-casing xml:, xmlns= and xmlns:foo= in ParseNodeToQName. */
#define IS_XML(str)                                                           \
    (JSSTRING_LENGTH(str) == 3 && IS_XML_CHARS(JSSTRING_CHARS(str)))

#define IS_XMLNS(str)                                                         \
    (JSSTRING_LENGTH(str) == 5 && IS_XMLNS_CHARS(JSSTRING_CHARS(str)))

#define IS_XML_CHARS(chars)                                                   \
    (JS_TOLOWER((chars)[0]) == 'x' &&                                         \
     JS_TOLOWER((chars)[1]) == 'm' &&                                         \
     JS_TOLOWER((chars)[2]) == 'l')

#define HAS_NS_AFTER_XML(chars)                                               \
    (JS_TOLOWER((chars)[3]) == 'n' &&                                         \
     JS_TOLOWER((chars)[4]) == 's')

#define IS_XMLNS_CHARS(chars)                                                 \
    (IS_XML_CHARS(chars) && HAS_NS_AFTER_XML(chars))

#define STARTS_WITH_XML(chars,length)                                         \
    (length >= 3 && IS_XML_CHARS(chars))

static const char xml_namespace_str[] = "http://www.w3.org/XML/1998/namespace";
static const char xmlns_namespace_str[] = "http://www.w3.org/2000/xmlns/";

static JSObject *
ParseNodeToQName(JSContext *cx, JSParseContext *pc, JSParseNode *pn,
                 JSXMLArray *inScopeNSes, JSBool isAttributeName)
{
    JSString *str, *uri, *prefix, *localName;
    size_t length, offset;
    const jschar *start, *limit, *colon;
    uint32 n;
    JSObject *ns;
    JSString *nsprefix;

    JS_ASSERT(pn->pn_arity == PN_NULLARY);
    str = ATOM_TO_STRING(pn->pn_atom);
    JSSTRING_CHARS_AND_LENGTH(str, start, length);
    JS_ASSERT(length != 0 && *start != '@');
    JS_ASSERT(length != 1 || *start != '*');

    uri = cx->runtime->emptyString;
    limit = start + length;
    colon = js_strchr_limit(start, ':', limit);
    if (colon) {
        offset = PTRDIFF(colon, start, jschar);
        prefix = js_NewDependentString(cx, str, 0, offset);
        if (!prefix)
            return NULL;

        if (STARTS_WITH_XML(start, offset)) {
            if (offset == 3) {
                uri = JS_InternString(cx, xml_namespace_str);
                if (!uri)
                    return NULL;
            } else if (offset == 5 && HAS_NS_AFTER_XML(start)) {
                uri = JS_InternString(cx, xmlns_namespace_str);
                if (!uri)
                    return NULL;
            } else {
                uri = NULL;
            }
        } else {
            uri = NULL;
            n = inScopeNSes->length;
            while (n != 0) {
                --n;
                ns = XMLARRAY_MEMBER(inScopeNSes, n, JSObject);
                nsprefix = GetPrefix(ns);
                if (nsprefix && js_EqualStrings(nsprefix, prefix)) {
                    uri = GetURI(ns);
                    break;
                }
            }
        }

        if (!uri) {
            js_ReportCompileErrorNumber(cx, &pc->tokenStream, pn,
                                        JSREPORT_ERROR,
                                        JSMSG_BAD_XML_NAMESPACE,
                                        js_ValueToPrintableString(cx,
                                            STRING_TO_JSVAL(prefix)));
            return NULL;
        }

        localName = js_NewStringCopyN(cx, colon + 1, length - (offset + 1));
        if (!localName)
            return NULL;
    } else {
        if (isAttributeName) {
            /*
             * An unprefixed attribute is not in any namespace, so set prefix
             * as well as uri to the empty string.
             */
            prefix = uri;
        } else {
            /*
             * Loop from back to front looking for the closest declared default
             * namespace.
             */
            n = inScopeNSes->length;
            while (n != 0) {
                --n;
                ns = XMLARRAY_MEMBER(inScopeNSes, n, JSObject);
                nsprefix = GetPrefix(ns);
                if (!nsprefix || IS_EMPTY(nsprefix)) {
                    uri = GetURI(ns);
                    break;
                }
            }
            prefix = IS_EMPTY(uri) ? cx->runtime->emptyString : NULL;
        }
        localName = str;
    }

    return NewXMLQName(cx, uri, prefix, localName);
}

static JSString *
ChompXMLWhitespace(JSContext *cx, JSString *str)
{
    size_t length, newlength, offset;
    const jschar *cp, *start, *end;
    jschar c;

    JSSTRING_CHARS_AND_LENGTH(str, start, length);
    for (cp = start, end = cp + length; cp < end; cp++) {
        c = *cp;
        if (!JS_ISXMLSPACE(c))
            break;
    }
    while (end > cp) {
        c = end[-1];
        if (!JS_ISXMLSPACE(c))
            break;
        --end;
    }
    newlength = PTRDIFF(end, cp, jschar);
    if (newlength == length)
        return str;
    offset = PTRDIFF(cp, start, jschar);
    return js_NewDependentString(cx, str, offset, newlength);
}

static JSXML *
ParseNodeToXML(JSContext *cx, JSParseContext *pc, JSParseNode *pn,
               JSXMLArray *inScopeNSes, uintN flags)
{
    JSXML *xml, *kid, *attr, *attrj;
    JSString *str;
    uint32 length, n, i, j;
    JSParseNode *pn2, *pn3, *head, **pnp;
    JSObject *ns;
    JSObject *qn, *attrjqn;
    JSXMLClass xml_class;
    int stackDummy;

    if (!JS_CHECK_STACK_SIZE(cx, stackDummy)) {
        js_ReportCompileErrorNumber(cx, &pc->tokenStream, pn, JSREPORT_ERROR,
                                    JSMSG_OVER_RECURSED);
        return NULL;
    }

#define PN2X_SKIP_CHILD ((JSXML *) 1)

    /*
     * Cases return early to avoid common code that gets an outermost xml's
     * object, which protects GC-things owned by xml and its descendants from
     * garbage collection.
     */
    xml = NULL;
    if (!js_EnterLocalRootScope(cx))
        return NULL;
    switch (pn->pn_type) {
      case TOK_XMLELEM:
        length = inScopeNSes->length;
        pn2 = pn->pn_head;
        xml = ParseNodeToXML(cx, pc, pn2, inScopeNSes, flags);
        if (!xml)
            goto fail;

        flags &= ~XSF_PRECOMPILED_ROOT;
        n = pn->pn_count;
        JS_ASSERT(n >= 2);
        n -= 2;
        if (!XMLArraySetCapacity(cx, &xml->xml_kids, n))
            goto fail;

        i = 0;
        while ((pn2 = pn2->pn_next) != NULL) {
            if (!pn2->pn_next) {
                /* Don't append the end tag! */
                JS_ASSERT(pn2->pn_type == TOK_XMLETAGO);
                break;
            }

            if ((flags & XSF_IGNORE_WHITESPACE) &&
                n > 1 && pn2->pn_type == TOK_XMLSPACE) {
                --n;
                continue;
            }

            kid = ParseNodeToXML(cx, pc, pn2, inScopeNSes, flags);
            if (kid == PN2X_SKIP_CHILD) {
                --n;
                continue;
            }

            if (!kid)
                goto fail;

            /* Store kid in xml right away, to protect it from GC. */
            XMLARRAY_SET_MEMBER(&xml->xml_kids, i, kid);
            kid->parent = xml;
            ++i;

            /* XXX where is this documented in an XML spec, or in E4X? */
            if ((flags & XSF_IGNORE_WHITESPACE) &&
                n > 1 && kid->xml_class == JSXML_CLASS_TEXT) {
                str = ChompXMLWhitespace(cx, kid->xml_value);
                if (!str)
                    goto fail;
                kid->xml_value = str;
            }
        }

        JS_ASSERT(i == n);
        if (n < pn->pn_count - 2)
            XMLArrayTrim(&xml->xml_kids);
        XMLARRAY_TRUNCATE(cx, inScopeNSes, length);
        break;

      case TOK_XMLLIST:
        xml = js_NewXML(cx, JSXML_CLASS_LIST);
        if (!xml)
            goto fail;

        n = pn->pn_count;
        if (!XMLArraySetCapacity(cx, &xml->xml_kids, n))
            goto fail;

        i = 0;
        for (pn2 = pn->pn_head; pn2; pn2 = pn2->pn_next) {
            /*
             * Always ignore insignificant whitespace in lists -- we shouldn't
             * condition this on an XML.ignoreWhitespace setting when the list
             * constructor is XMLList (note XML/XMLList unification hazard).
             */
            if (pn2->pn_type == TOK_XMLSPACE) {
                --n;
                continue;
            }

            kid = ParseNodeToXML(cx, pc, pn2, inScopeNSes, flags);
            if (kid == PN2X_SKIP_CHILD) {
                --n;
                continue;
            }

            if (!kid)
                goto fail;

            XMLARRAY_SET_MEMBER(&xml->xml_kids, i, kid);
            ++i;
        }

        if (n < pn->pn_count)
            XMLArrayTrim(&xml->xml_kids);
        break;

      case TOK_XMLSTAGO:
      case TOK_XMLPTAGC:
        length = inScopeNSes->length;
        pn2 = pn->pn_head;
        JS_ASSERT(pn2->pn_type == TOK_XMLNAME);
        if (pn2->pn_arity == PN_LIST)
            goto syntax;

        xml = js_NewXML(cx, JSXML_CLASS_ELEMENT);
        if (!xml)
            goto fail;

        /* First pass: check syntax and process namespace declarations. */
        JS_ASSERT(pn->pn_count >= 1);
        n = pn->pn_count - 1;
        pnp = &pn2->pn_next;
        head = *pnp;
        while ((pn2 = *pnp) != NULL) {
            size_t length;
            const jschar *chars;

            if (pn2->pn_type != TOK_XMLNAME || pn2->pn_arity != PN_NULLARY)
                goto syntax;

            /* Enforce "Well-formedness constraint: Unique Att Spec". */
            for (pn3 = head; pn3 != pn2; pn3 = pn3->pn_next->pn_next) {
                if (pn3->pn_atom == pn2->pn_atom) {
                    js_ReportCompileErrorNumber(cx, &pc->tokenStream, pn2,
                                                JSREPORT_ERROR,
                                                JSMSG_DUPLICATE_XML_ATTR,
                                                js_ValueToPrintableString(cx,
                                                    ATOM_KEY(pn2->pn_atom)));
                    goto fail;
                }
            }

            str = ATOM_TO_STRING(pn2->pn_atom);
            pn2 = pn2->pn_next;
            JS_ASSERT(pn2);
            if (pn2->pn_type != TOK_XMLATTR)
                goto syntax;

            JSSTRING_CHARS_AND_LENGTH(str, chars, length);
            if (length >= 5 &&
                IS_XMLNS_CHARS(chars) &&
                (length == 5 || chars[5] == ':')) {
                JSString *uri, *prefix;

                uri = ATOM_TO_STRING(pn2->pn_atom);
                if (length == 5) {
                    /* 10.3.2.1. Step 6(h)(i)(1)(a). */
                    prefix = cx->runtime->emptyString;
                } else {
                    prefix = js_NewStringCopyN(cx, chars + 6, length - 6);
                    if (!prefix)
                        goto fail;
                }

                /*
                 * Once the new ns is appended to xml->xml_namespaces, it is
                 * protected from GC by the object that owns xml -- which is
                 * either xml->object if outermost, or the object owning xml's
                 * oldest ancestor if !outermost.
                 */
                ns = NewXMLNamespace(cx, prefix, uri, JS_TRUE);
                if (!ns)
                    goto fail;

                /*
                 * Don't add a namespace that's already in scope.  If someone
                 * extracts a child property from its parent via [[Get]], then
                 * we enforce the invariant, noted many times in ECMA-357, that
                 * the child's namespaces form a possibly-improper superset of
                 * its ancestors' namespaces.
                 */
                if (!XMLARRAY_HAS_MEMBER(inScopeNSes, ns, namespace_identity)) {
                    if (!XMLARRAY_APPEND(cx, inScopeNSes, ns) ||
                        !XMLARRAY_APPEND(cx, &xml->xml_namespaces, ns)) {
                        goto fail;
                    }
                }

                JS_ASSERT(n >= 2);
                n -= 2;
                *pnp = pn2->pn_next;
                /* XXXbe recycle pn2 */
                continue;
            }

            pnp = &pn2->pn_next;
        }

        /*
         * If called from js_ParseNodeToXMLObject, emulate the effect of the
         * <parent xmlns='%s'>...</parent> wrapping done by "ToXML Applied to
         * the String Type" (ECMA-357 10.3.1).
         */
        if (flags & XSF_PRECOMPILED_ROOT) {
            JS_ASSERT(length >= 1);
            ns = XMLARRAY_MEMBER(inScopeNSes, 0, JSObject);
            JS_ASSERT(!XMLARRAY_HAS_MEMBER(&xml->xml_namespaces, ns,
                                           namespace_identity));
            ns = NewXMLNamespace(cx, GetPrefix(ns), GetURI(ns), JS_FALSE);
            if (!ns)
                goto fail;
            if (!XMLARRAY_APPEND(cx, &xml->xml_namespaces, ns))
                goto fail;
        }
        XMLArrayTrim(&xml->xml_namespaces);

        /* Second pass: process tag name and attributes, using namespaces. */
        pn2 = pn->pn_head;
        qn = ParseNodeToQName(cx, pc, pn2, inScopeNSes, JS_FALSE);
        if (!qn)
            goto fail;
        xml->name = qn;

        JS_ASSERT((n & 1) == 0);
        n >>= 1;
        if (!XMLArraySetCapacity(cx, &xml->xml_attrs, n))
            goto fail;

        for (i = 0; (pn2 = pn2->pn_next) != NULL; i++) {
            qn = ParseNodeToQName(cx, pc, pn2, inScopeNSes, JS_TRUE);
            if (!qn) {
                xml->xml_attrs.length = i;
                goto fail;
            }

            /*
             * Enforce "Well-formedness constraint: Unique Att Spec", part 2:
             * this time checking local name and namespace URI.
             */
            for (j = 0; j < i; j++) {
                attrj = XMLARRAY_MEMBER(&xml->xml_attrs, j, JSXML);
                attrjqn = attrj->name;
                if (js_EqualStrings(GetURI(attrjqn), GetURI(qn)) &&
                    js_EqualStrings(GetLocalName(attrjqn), GetLocalName(qn))) {
                    js_ReportCompileErrorNumber(cx, &pc->tokenStream, pn2,
                                                JSREPORT_ERROR,
                                                JSMSG_DUPLICATE_XML_ATTR,
                                                js_ValueToPrintableString(cx,
                                                    ATOM_KEY(pn2->pn_atom)));
                    goto fail;
                }
            }

            pn2 = pn2->pn_next;
            JS_ASSERT(pn2);
            JS_ASSERT(pn2->pn_type == TOK_XMLATTR);

            attr = js_NewXML(cx, JSXML_CLASS_ATTRIBUTE);
            if (!attr)
                goto fail;

            XMLARRAY_SET_MEMBER(&xml->xml_attrs, i, attr);
            attr->parent = xml;
            attr->name = qn;
            attr->xml_value = ATOM_TO_STRING(pn2->pn_atom);
        }

        /* Point tag closes its own namespace scope. */
        if (pn->pn_type == TOK_XMLPTAGC)
            XMLARRAY_TRUNCATE(cx, inScopeNSes, length);
        break;

      case TOK_XMLSPACE:
      case TOK_XMLTEXT:
      case TOK_XMLCDATA:
      case TOK_XMLCOMMENT:
      case TOK_XMLPI:
        str = ATOM_TO_STRING(pn->pn_atom);
        qn = NULL;
        if (pn->pn_type == TOK_XMLCOMMENT) {
            if (flags & XSF_IGNORE_COMMENTS)
                goto skip_child;
            xml_class = JSXML_CLASS_COMMENT;
        } else if (pn->pn_type == TOK_XMLPI) {
            if (IS_XML(str)) {
                js_ReportCompileErrorNumber(cx, &pc->tokenStream, pn,
                                            JSREPORT_ERROR,
                                            JSMSG_RESERVED_ID,
                                            js_ValueToPrintableString(cx,
                                                STRING_TO_JSVAL(str)));
                goto fail;
            }

            if (flags & XSF_IGNORE_PROCESSING_INSTRUCTIONS)
                goto skip_child;

            qn = ParseNodeToQName(cx, pc, pn, inScopeNSes, JS_FALSE);
            if (!qn)
                goto fail;

            str = pn->pn_atom2
                  ? ATOM_TO_STRING(pn->pn_atom2)
                  : cx->runtime->emptyString;
            xml_class = JSXML_CLASS_PROCESSING_INSTRUCTION;
        } else {
            /* CDATA section content, or element text. */
            xml_class = JSXML_CLASS_TEXT;
        }

        xml = js_NewXML(cx, xml_class);
        if (!xml)
            goto fail;
        xml->name = qn;
        if (pn->pn_type == TOK_XMLSPACE)
            xml->xml_flags |= XMLF_WHITESPACE_TEXT;
        xml->xml_value = str;
        break;

      default:
        goto syntax;
    }

    js_LeaveLocalRootScopeWithResult(cx, (jsval) xml);
    if ((flags & XSF_PRECOMPILED_ROOT) && !js_GetXMLObject(cx, xml))
        return NULL;
    return xml;

skip_child:
    js_LeaveLocalRootScope(cx);
    return PN2X_SKIP_CHILD;

#undef PN2X_SKIP_CHILD

syntax:
    js_ReportCompileErrorNumber(cx, &pc->tokenStream, pn, JSREPORT_ERROR,
                                JSMSG_BAD_XML_MARKUP);
fail:
    js_LeaveLocalRootScope(cx);
    return NULL;
}

/*
 * XML helper, object-ops, and library functions.  We start with the helpers,
 * in ECMA-357 order, but merging XML (9.1) and XMLList (9.2) helpers.
 */
static JSBool
GetXMLSetting(JSContext *cx, const char *name, jsval *vp)
{
    jsval v;

    if (!js_FindClassObject(cx, NULL, INT_TO_JSID(JSProto_XML), &v))
        return JS_FALSE;
    if (!VALUE_IS_FUNCTION(cx, v)) {
        *vp = JSVAL_VOID;
        return JS_TRUE;
    }
    return JS_GetProperty(cx, JSVAL_TO_OBJECT(v), name, vp);
}

static JSBool
FillSettingsCache(JSContext *cx)
{
    int i;
    const char *name;
    jsval v;

    /* Note: XML_PRETTY_INDENT is not a boolean setting. */
    for (i = XML_IGNORE_COMMENTS; i < XML_PRETTY_INDENT; i++) {
        name = xml_static_props[i].name;
        if (!GetXMLSetting(cx, name, &v))
            return JS_FALSE;
        if (js_ValueToBoolean(v))
            cx->xmlSettingFlags |= JS_BIT(i);
        else
            cx->xmlSettingFlags &= ~JS_BIT(i);
    }

    cx->xmlSettingFlags |= XSF_CACHE_VALID;
    return JS_TRUE;
}

static JSBool
GetBooleanXMLSetting(JSContext *cx, const char *name, JSBool *bp)
{
    int i;

    if (!(cx->xmlSettingFlags & XSF_CACHE_VALID) && !FillSettingsCache(cx))
        return JS_FALSE;

    for (i = 0; xml_static_props[i].name; i++) {
        if (!strcmp(xml_static_props[i].name, name)) {
            *bp = (cx->xmlSettingFlags & JS_BIT(i)) != 0;
            return JS_TRUE;
        }
    }
    *bp = JS_FALSE;
    return JS_TRUE;
}

static JSBool
GetUint32XMLSetting(JSContext *cx, const char *name, uint32 *uip)
{
    jsval v;

    return GetXMLSetting(cx, name, &v) && JS_ValueToECMAUint32(cx, v, uip);
}

static JSBool
GetXMLSettingFlags(JSContext *cx, uintN *flagsp)
{
    JSBool flag;

    /* Just get the first flag to validate the setting flags cache. */
    if (!GetBooleanXMLSetting(cx, js_ignoreComments_str, &flag))
        return JS_FALSE;
    *flagsp = cx->xmlSettingFlags;
    return JS_TRUE;
}

static JSXML *
ParseXMLSource(JSContext *cx, JSString *src)
{
    jsval nsval;
    JSString *uri;
    size_t urilen, srclen, length, offset, dstlen;
    jschar *chars;
    const jschar *srcp, *endp;
    JSXML *xml;
    JSParseContext pc;
    const char *filename;
    uintN lineno;
    JSStackFrame *fp;
    JSOp op;
    JSParseNode *pn;
    JSXMLArray nsarray;
    uintN flags;

    static const char prefix[] = "<parent xmlns=\"";
    static const char middle[] = "\">";
    static const char suffix[] = "</parent>";

#define constrlen(constr)   (sizeof(constr) - 1)

    if (!js_GetDefaultXMLNamespace(cx, &nsval))
        return NULL;
    uri = GetURI(JSVAL_TO_OBJECT(nsval));
    uri = js_EscapeAttributeValue(cx, uri, JS_FALSE);

    urilen = JSSTRING_LENGTH(uri);
    srclen = JSSTRING_LENGTH(src);
    length = constrlen(prefix) + urilen + constrlen(middle) + srclen +
             constrlen(suffix);

    chars = (jschar *) JS_malloc(cx, (length + 1) * sizeof(jschar));
    if (!chars)
        return NULL;

    dstlen = length;
    js_InflateStringToBuffer(cx, prefix, constrlen(prefix), chars, &dstlen);
    offset = dstlen;
    js_strncpy(chars + offset, JSSTRING_CHARS(uri), urilen);
    offset += urilen;
    dstlen = length - offset + 1;
    js_InflateStringToBuffer(cx, middle, constrlen(middle), chars + offset,
                             &dstlen);
    offset += dstlen;
    srcp = JSSTRING_CHARS(src);
    js_strncpy(chars + offset, srcp, srclen);
    offset += srclen;
    dstlen = length - offset + 1;
    js_InflateStringToBuffer(cx, suffix, constrlen(suffix), chars + offset,
                             &dstlen);
    chars [offset + dstlen] = 0;

    xml = NULL;
    for (fp = cx->fp; fp && !fp->regs; fp = fp->down)
        JS_ASSERT(!fp->script);
    filename = NULL;
    lineno = 1;
    if (fp) {
        op = (JSOp) *fp->regs->pc;
        if (op == JSOP_TOXML || op == JSOP_TOXMLLIST) {
            filename = fp->script->filename;
            lineno = js_FramePCToLineNumber(cx, fp);
            for (endp = srcp + srclen; srcp < endp; srcp++) {
                if (*srcp == '\n')
                    --lineno;
            }
        }
    }

    if (!js_InitParseContext(cx, &pc, NULL, NULL, chars, length, NULL,
                             filename, lineno))
        goto out;
    pn = js_ParseXMLText(cx, cx->fp->scopeChain, &pc, JS_FALSE);
    if (pn && XMLArrayInit(cx, &nsarray, 1)) {
        if (GetXMLSettingFlags(cx, &flags))
            xml = ParseNodeToXML(cx, &pc, pn, &nsarray, flags);

        XMLArrayFinish(cx, &nsarray);
    }
    js_FinishParseContext(cx, &pc);

out:
    JS_free(cx, chars);
    return xml;

#undef constrlen
}

/*
 * Errata in 10.3.1, 10.4.1, and 13.4.4.24 (at least).
 *
 * 10.3.1 Step 6(a) fails to NOTE that implementations that do not enforce
 * the constraint:
 *
 *     for all x belonging to XML:
 *         x.[[InScopeNamespaces]] >= x.[[Parent]].[[InScopeNamespaces]]
 *
 * must union x.[[InScopeNamespaces]] into x[0].[[InScopeNamespaces]] here
 * (in new sub-step 6(a), renumbering the others to (b) and (c)).
 *
 * Same goes for 10.4.1 Step 7(a).
 *
 * In order for XML.prototype.namespaceDeclarations() to work correctly, the
 * default namespace thereby unioned into x[0].[[InScopeNamespaces]] must be
 * flagged as not declared, so that 13.4.4.24 Step 8(a) can exclude all such
 * undeclared namespaces associated with x not belonging to ancestorNS.
 */
static JSXML *
OrphanXMLChild(JSContext *cx, JSXML *xml, uint32 i)
{
    JSObject *ns;

    ns = XMLARRAY_MEMBER(&xml->xml_namespaces, 0, JSObject);
    xml = XMLARRAY_MEMBER(&xml->xml_kids, i, JSXML);
    if (!ns || !xml)
        return xml;
    if (xml->xml_class == JSXML_CLASS_ELEMENT) {
        if (!XMLARRAY_APPEND(cx, &xml->xml_namespaces, ns))
            return NULL;
        ns->fslots[JSSLOT_DECLARED] = JSVAL_VOID;
    }
    xml->parent = NULL;
    return xml;
}

static JSObject *
ToXML(JSContext *cx, jsval v)
{
    JSObject *obj;
    JSXML *xml;
    JSClass *clasp;
    JSString *str;
    uint32 length;

    if (JSVAL_IS_PRIMITIVE(v)) {
        if (JSVAL_IS_NULL(v) || JSVAL_IS_VOID(v))
            goto bad;
    } else {
        obj = JSVAL_TO_OBJECT(v);
        if (OBJECT_IS_XML(cx, obj)) {
            xml = (JSXML *) JS_GetPrivate(cx, obj);
            if (xml->xml_class == JSXML_CLASS_LIST) {
                if (xml->xml_kids.length != 1)
                    goto bad;
                xml = XMLARRAY_MEMBER(&xml->xml_kids, 0, JSXML);
                if (xml) {
                    JS_ASSERT(xml->xml_class != JSXML_CLASS_LIST);
                    return js_GetXMLObject(cx, xml);
                }
            }
            return obj;
        }

        clasp = OBJ_GET_CLASS(cx, obj);
        if (clasp->flags & JSCLASS_DOCUMENT_OBSERVER) {
            JS_ASSERT(0);
        }

        if (clasp != &js_StringClass &&
            clasp != &js_NumberClass &&
            clasp != &js_BooleanClass) {
            goto bad;
        }
    }

    str = js_ValueToString(cx, v);
    if (!str)
        return NULL;
    if (IS_EMPTY(str)) {
        length = 0;
#ifdef __GNUC__         /* suppress bogus gcc warnings */
        xml = NULL;
#endif
    } else {
        xml = ParseXMLSource(cx, str);
        if (!xml)
            return NULL;
        length = JSXML_LENGTH(xml);
    }

    if (length == 0) {
        obj = js_NewXMLObject(cx, JSXML_CLASS_TEXT);
        if (!obj)
            return NULL;
    } else if (length == 1) {
        xml = OrphanXMLChild(cx, xml, 0);
        if (!xml)
            return NULL;
        obj = js_GetXMLObject(cx, xml);
        if (!obj)
            return NULL;
    } else {
        JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL, JSMSG_SYNTAX_ERROR);
        return NULL;
    }
    return obj;

bad:
    js_ReportValueError(cx, JSMSG_BAD_XML_CONVERSION,
                        JSDVG_IGNORE_STACK, v, NULL);
    return NULL;
}

static JSBool
Append(JSContext *cx, JSXML *list, JSXML *kid);

static JSObject *
ToXMLList(JSContext *cx, jsval v)
{
    JSObject *obj, *listobj;
    JSXML *xml, *list, *kid;
    JSClass *clasp;
    JSString *str;
    uint32 i, length;

    if (JSVAL_IS_PRIMITIVE(v)) {
        if (JSVAL_IS_NULL(v) || JSVAL_IS_VOID(v))
            goto bad;
    } else {
        obj = JSVAL_TO_OBJECT(v);
        if (OBJECT_IS_XML(cx, obj)) {
            xml = (JSXML *) JS_GetPrivate(cx, obj);
            if (xml->xml_class != JSXML_CLASS_LIST) {
                listobj = js_NewXMLObject(cx, JSXML_CLASS_LIST);
                if (!listobj)
                    return NULL;
                list = (JSXML *) JS_GetPrivate(cx, listobj);
                if (!Append(cx, list, xml))
                    return NULL;
                return listobj;
            }
            return obj;
        }

        clasp = OBJ_GET_CLASS(cx, obj);
        if (clasp->flags & JSCLASS_DOCUMENT_OBSERVER) {
            JS_ASSERT(0);
        }

        if (clasp != &js_StringClass &&
            clasp != &js_NumberClass &&
            clasp != &js_BooleanClass) {
            goto bad;
        }
    }

    str = js_ValueToString(cx, v);
    if (!str)
        return NULL;
    if (IS_EMPTY(str)) {
        xml = NULL;
        length = 0;
    } else {
        if (!js_EnterLocalRootScope(cx))
            return NULL;
        xml = ParseXMLSource(cx, str);
        if (!xml) {
            js_LeaveLocalRootScope(cx);
            return NULL;
        }
        length = JSXML_LENGTH(xml);
    }

    listobj = js_NewXMLObject(cx, JSXML_CLASS_LIST);
    if (listobj) {
        list = (JSXML *) JS_GetPrivate(cx, listobj);
        for (i = 0; i < length; i++) {
            kid = OrphanXMLChild(cx, xml, i);
            if (!kid || !Append(cx, list, kid)) {
                listobj = NULL;
                break;
            }
        }
    }

    if (xml)
        js_LeaveLocalRootScopeWithResult(cx, (jsval) listobj);
    return listobj;

bad:
    js_ReportValueError(cx, JSMSG_BAD_XMLLIST_CONVERSION,
                        JSDVG_IGNORE_STACK, v, NULL);
    return NULL;
}

/*
 * ECMA-357 10.2.1 Steps 5-7 pulled out as common subroutines of XMLToXMLString
 * and their library-public js_* counterparts.  The guts of MakeXMLCDataString,
 * MakeXMLCommentString, and MakeXMLPIString are further factored into a common
 * MakeXMLSpecialString subroutine.
 *
 * These functions take ownership of sb->base, if sb is non-null, in all cases
 * of success or failure.
 */
static JSString *
MakeXMLSpecialString(JSContext *cx, JSStringBuffer *sb,
                     JSString *str, JSString *str2,
                     const jschar *prefix, size_t prefixlength,
                     const jschar *suffix, size_t suffixlength)
{
    JSStringBuffer localSB;
    size_t length, length2, newlength;
    jschar *bp, *base;

    if (!sb) {
        sb = &localSB;
        js_InitStringBuffer(sb);
    }

    length = JSSTRING_LENGTH(str);
    length2 = str2 ? JSSTRING_LENGTH(str2) : 0;
    newlength = STRING_BUFFER_OFFSET(sb) +
                prefixlength + length + ((length2 != 0) ? 1 + length2 : 0) +
                suffixlength;
    bp = base = (jschar *)
                JS_r