1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/dom/xbl/nsXBLProtoImplField.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,494 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#include "nsIAtom.h"
1.10 +#include "nsIContent.h"
1.11 +#include "nsString.h"
1.12 +#include "nsJSUtils.h"
1.13 +#include "jsapi.h"
1.14 +#include "js/CharacterEncoding.h"
1.15 +#include "nsUnicharUtils.h"
1.16 +#include "nsReadableUtils.h"
1.17 +#include "nsXBLProtoImplField.h"
1.18 +#include "nsIScriptContext.h"
1.19 +#include "nsIURI.h"
1.20 +#include "nsXBLSerialize.h"
1.21 +#include "nsXBLPrototypeBinding.h"
1.22 +#include "mozilla/dom/BindingUtils.h"
1.23 +#include "mozilla/dom/ScriptSettings.h"
1.24 +#include "nsGlobalWindow.h"
1.25 +#include "xpcpublic.h"
1.26 +#include "WrapperFactory.h"
1.27 +
1.28 +using namespace mozilla;
1.29 +using namespace mozilla::dom;
1.30 +
1.31 +nsXBLProtoImplField::nsXBLProtoImplField(const char16_t* aName, const char16_t* aReadOnly)
1.32 + : mNext(nullptr),
1.33 + mFieldText(nullptr),
1.34 + mFieldTextLength(0),
1.35 + mLineNumber(0)
1.36 +{
1.37 + MOZ_COUNT_CTOR(nsXBLProtoImplField);
1.38 + mName = NS_strdup(aName); // XXXbz make more sense to use a stringbuffer?
1.39 +
1.40 + mJSAttributes = JSPROP_ENUMERATE;
1.41 + if (aReadOnly) {
1.42 + nsAutoString readOnly; readOnly.Assign(aReadOnly);
1.43 + if (readOnly.LowerCaseEqualsLiteral("true"))
1.44 + mJSAttributes |= JSPROP_READONLY;
1.45 + }
1.46 +}
1.47 +
1.48 +
1.49 +nsXBLProtoImplField::nsXBLProtoImplField(const bool aIsReadOnly)
1.50 + : mNext(nullptr),
1.51 + mFieldText(nullptr),
1.52 + mFieldTextLength(0),
1.53 + mLineNumber(0)
1.54 +{
1.55 + MOZ_COUNT_CTOR(nsXBLProtoImplField);
1.56 +
1.57 + mJSAttributes = JSPROP_ENUMERATE;
1.58 + if (aIsReadOnly)
1.59 + mJSAttributes |= JSPROP_READONLY;
1.60 +}
1.61 +
1.62 +nsXBLProtoImplField::~nsXBLProtoImplField()
1.63 +{
1.64 + MOZ_COUNT_DTOR(nsXBLProtoImplField);
1.65 + if (mFieldText)
1.66 + nsMemory::Free(mFieldText);
1.67 + NS_Free(mName);
1.68 + NS_CONTENT_DELETE_LIST_MEMBER(nsXBLProtoImplField, this, mNext);
1.69 +}
1.70 +
1.71 +void
1.72 +nsXBLProtoImplField::AppendFieldText(const nsAString& aText)
1.73 +{
1.74 + if (mFieldText) {
1.75 + nsDependentString fieldTextStr(mFieldText, mFieldTextLength);
1.76 + nsAutoString newFieldText = fieldTextStr + aText;
1.77 + char16_t* temp = mFieldText;
1.78 + mFieldText = ToNewUnicode(newFieldText);
1.79 + mFieldTextLength = newFieldText.Length();
1.80 + nsMemory::Free(temp);
1.81 + }
1.82 + else {
1.83 + mFieldText = ToNewUnicode(aText);
1.84 + mFieldTextLength = aText.Length();
1.85 + }
1.86 +}
1.87 +
1.88 +// XBL fields are represented on elements inheriting that field a bit trickily.
1.89 +// When setting up the XBL prototype object, we install accessors for the fields
1.90 +// on the prototype object. Those accessors, when used, will then (via
1.91 +// InstallXBLField below) reify a property for the field onto the actual XBL-backed
1.92 +// element.
1.93 +//
1.94 +// The accessor property is a plain old property backed by a getter function and
1.95 +// a setter function. These properties are backed by the FieldGetter and
1.96 +// FieldSetter natives; they're created by InstallAccessors. The precise field to be
1.97 +// reified is identified using two extra slots on the getter/setter functions.
1.98 +// XBLPROTO_SLOT stores the XBL prototype object that provides the field.
1.99 +// FIELD_SLOT stores the name of the field, i.e. its JavaScript property name.
1.100 +//
1.101 +// This two-step field installation process -- creating an accessor on the
1.102 +// prototype, then have that reify an own property on the actual element -- is
1.103 +// admittedly convoluted. Better would be for XBL-backed elements to be proxies
1.104 +// that could resolve fields onto themselves. But given that XBL bindings are
1.105 +// associated with elements mutably -- you can add/remove/change -moz-binding
1.106 +// whenever you want, alas -- doing so would require all elements to be proxies,
1.107 +// which isn't performant now. So we do this two-step instead.
1.108 +static const uint32_t XBLPROTO_SLOT = 0;
1.109 +static const uint32_t FIELD_SLOT = 1;
1.110 +
1.111 +bool
1.112 +ValueHasISupportsPrivate(JS::Handle<JS::Value> v)
1.113 +{
1.114 + if (!v.isObject()) {
1.115 + return false;
1.116 + }
1.117 +
1.118 + const DOMClass* domClass = GetDOMClass(&v.toObject());
1.119 + if (domClass) {
1.120 + return domClass->mDOMObjectIsISupports;
1.121 + }
1.122 +
1.123 + const JSClass* clasp = ::JS_GetClass(&v.toObject());
1.124 + const uint32_t HAS_PRIVATE_NSISUPPORTS =
1.125 + JSCLASS_HAS_PRIVATE | JSCLASS_PRIVATE_IS_NSISUPPORTS;
1.126 + return (clasp->flags & HAS_PRIVATE_NSISUPPORTS) == HAS_PRIVATE_NSISUPPORTS;
1.127 +}
1.128 +
1.129 +#ifdef DEBUG
1.130 +static bool
1.131 +ValueHasISupportsPrivate(JSContext* cx, const JS::Value& aVal)
1.132 +{
1.133 + JS::Rooted<JS::Value> v(cx, aVal);
1.134 + return ValueHasISupportsPrivate(v);
1.135 +}
1.136 +#endif
1.137 +
1.138 +// Define a shadowing property on |this| for the XBL field defined by the
1.139 +// contents of the callee's reserved slots. If the property was defined,
1.140 +// *installed will be true, and idp will be set to the property name that was
1.141 +// defined.
1.142 +static bool
1.143 +InstallXBLField(JSContext* cx,
1.144 + JS::Handle<JSObject*> callee, JS::Handle<JSObject*> thisObj,
1.145 + JS::MutableHandle<jsid> idp, bool* installed)
1.146 +{
1.147 + *installed = false;
1.148 +
1.149 + // First ensure |this| is a reasonable XBL bound node.
1.150 + //
1.151 + // FieldAccessorGuard already determined whether |thisObj| was acceptable as
1.152 + // |this| in terms of not throwing a TypeError. Assert this for good measure.
1.153 + MOZ_ASSERT(ValueHasISupportsPrivate(cx, JS::ObjectValue(*thisObj)));
1.154 +
1.155 + // But there are some cases where we must accept |thisObj| but not install a
1.156 + // property on it, or otherwise touch it. Hence this split of |this|-vetting
1.157 + // duties.
1.158 + nsISupports* native =
1.159 + nsContentUtils::XPConnect()->GetNativeOfWrapper(cx, thisObj);
1.160 + if (!native) {
1.161 + // Looks like whatever |thisObj| is it's not our nsIContent. It might well
1.162 + // be the proto our binding installed, however, where the private is the
1.163 + // nsXBLDocumentInfo, so just baul out quietly. Do NOT throw an exception
1.164 + // here.
1.165 + //
1.166 + // We could make this stricter by checking the class maybe, but whatever.
1.167 + return true;
1.168 + }
1.169 +
1.170 + nsCOMPtr<nsIContent> xblNode = do_QueryInterface(native);
1.171 + if (!xblNode) {
1.172 + xpc::Throw(cx, NS_ERROR_UNEXPECTED);
1.173 + return false;
1.174 + }
1.175 +
1.176 + // Now that |this| is okay, actually install the field.
1.177 +
1.178 + // Because of the possibility (due to XBL binding inheritance, because each
1.179 + // XBL binding lives in its own global object) that |this| might be in a
1.180 + // different compartment from the callee (not to mention that this method can
1.181 + // be called with an arbitrary |this| regardless of how insane XBL is), and
1.182 + // because in this method we've entered |this|'s compartment (see in
1.183 + // Field[GS]etter where we attempt a cross-compartment call), we must enter
1.184 + // the callee's compartment to access its reserved slots.
1.185 + nsXBLPrototypeBinding* protoBinding;
1.186 + nsDependentJSString fieldName;
1.187 + {
1.188 + JSAutoCompartment ac(cx, callee);
1.189 +
1.190 + JS::Rooted<JSObject*> xblProto(cx);
1.191 + xblProto = &js::GetFunctionNativeReserved(callee, XBLPROTO_SLOT).toObject();
1.192 +
1.193 + JS::Rooted<JS::Value> name(cx, js::GetFunctionNativeReserved(callee, FIELD_SLOT));
1.194 + JSFlatString* fieldStr = JS_ASSERT_STRING_IS_FLAT(name.toString());
1.195 + fieldName.init(fieldStr);
1.196 +
1.197 + MOZ_ALWAYS_TRUE(JS_ValueToId(cx, name, idp));
1.198 +
1.199 + // If a separate XBL scope is being used, the callee is not same-compartment
1.200 + // with the xbl prototype, and the object is a cross-compartment wrapper.
1.201 + xblProto = js::UncheckedUnwrap(xblProto);
1.202 + JSAutoCompartment ac2(cx, xblProto);
1.203 + JS::Value slotVal = ::JS_GetReservedSlot(xblProto, 0);
1.204 + protoBinding = static_cast<nsXBLPrototypeBinding*>(slotVal.toPrivate());
1.205 + MOZ_ASSERT(protoBinding);
1.206 + }
1.207 +
1.208 + nsXBLProtoImplField* field = protoBinding->FindField(fieldName);
1.209 + MOZ_ASSERT(field);
1.210 +
1.211 + nsresult rv = field->InstallField(thisObj, protoBinding->DocURI(), installed);
1.212 + if (NS_SUCCEEDED(rv)) {
1.213 + return true;
1.214 + }
1.215 +
1.216 + if (!::JS_IsExceptionPending(cx)) {
1.217 + xpc::Throw(cx, rv);
1.218 + }
1.219 + return false;
1.220 +}
1.221 +
1.222 +bool
1.223 +FieldGetterImpl(JSContext *cx, JS::CallArgs args)
1.224 +{
1.225 + JS::Handle<JS::Value> thisv = args.thisv();
1.226 + MOZ_ASSERT(ValueHasISupportsPrivate(thisv));
1.227 +
1.228 + JS::Rooted<JSObject*> thisObj(cx, &thisv.toObject());
1.229 +
1.230 + // We should be in the compartment of |this|. If we got here via nativeCall,
1.231 + // |this| is not same-compartment with |callee|, and it's possible via
1.232 + // asymmetric security semantics that |args.calleev()| is actually a security
1.233 + // wrapper. In this case, we know we want to do an unsafe unwrap, and
1.234 + // InstallXBLField knows how to handle cross-compartment pointers.
1.235 + bool installed = false;
1.236 + JS::Rooted<JSObject*> callee(cx, js::UncheckedUnwrap(&args.calleev().toObject()));
1.237 + JS::Rooted<jsid> id(cx);
1.238 + if (!InstallXBLField(cx, callee, thisObj, &id, &installed)) {
1.239 + return false;
1.240 + }
1.241 +
1.242 + if (!installed) {
1.243 + args.rval().setUndefined();
1.244 + return true;
1.245 + }
1.246 +
1.247 + JS::Rooted<JS::Value> v(cx);
1.248 + if (!JS_GetPropertyById(cx, thisObj, id, &v)) {
1.249 + return false;
1.250 + }
1.251 + args.rval().set(v);
1.252 + return true;
1.253 +}
1.254 +
1.255 +static bool
1.256 +FieldGetter(JSContext *cx, unsigned argc, JS::Value *vp)
1.257 +{
1.258 + JS::CallArgs args = JS::CallArgsFromVp(argc, vp);
1.259 + return JS::CallNonGenericMethod<ValueHasISupportsPrivate, FieldGetterImpl>
1.260 + (cx, args);
1.261 +}
1.262 +
1.263 +bool
1.264 +FieldSetterImpl(JSContext *cx, JS::CallArgs args)
1.265 +{
1.266 + JS::Handle<JS::Value> thisv = args.thisv();
1.267 + MOZ_ASSERT(ValueHasISupportsPrivate(thisv));
1.268 +
1.269 + JS::Rooted<JSObject*> thisObj(cx, &thisv.toObject());
1.270 +
1.271 + // We should be in the compartment of |this|. If we got here via nativeCall,
1.272 + // |this| is not same-compartment with |callee|, and it's possible via
1.273 + // asymmetric security semantics that |args.calleev()| is actually a security
1.274 + // wrapper. In this case, we know we want to do an unsafe unwrap, and
1.275 + // InstallXBLField knows how to handle cross-compartment pointers.
1.276 + bool installed = false;
1.277 + JS::Rooted<JSObject*> callee(cx, js::UncheckedUnwrap(&args.calleev().toObject()));
1.278 + JS::Rooted<jsid> id(cx);
1.279 + if (!InstallXBLField(cx, callee, thisObj, &id, &installed)) {
1.280 + return false;
1.281 + }
1.282 +
1.283 + if (installed) {
1.284 + if (!::JS_SetPropertyById(cx, thisObj, id, args.get(0))) {
1.285 + return false;
1.286 + }
1.287 + }
1.288 + args.rval().setUndefined();
1.289 + return true;
1.290 +}
1.291 +
1.292 +static bool
1.293 +FieldSetter(JSContext *cx, unsigned argc, JS::Value *vp)
1.294 +{
1.295 + JS::CallArgs args = JS::CallArgsFromVp(argc, vp);
1.296 + return JS::CallNonGenericMethod<ValueHasISupportsPrivate, FieldSetterImpl>
1.297 + (cx, args);
1.298 +}
1.299 +
1.300 +nsresult
1.301 +nsXBLProtoImplField::InstallAccessors(JSContext* aCx,
1.302 + JS::Handle<JSObject*> aTargetClassObject)
1.303 +{
1.304 + MOZ_ASSERT(js::IsObjectInContextCompartment(aTargetClassObject, aCx));
1.305 + JS::Rooted<JSObject*> globalObject(aCx, JS_GetGlobalForObject(aCx, aTargetClassObject));
1.306 + JS::Rooted<JSObject*> scopeObject(aCx, xpc::GetXBLScopeOrGlobal(aCx, globalObject));
1.307 + NS_ENSURE_TRUE(scopeObject, NS_ERROR_OUT_OF_MEMORY);
1.308 +
1.309 + // Don't install it if the field is empty; see also InstallField which also must
1.310 + // implement the not-empty requirement.
1.311 + if (IsEmpty()) {
1.312 + return NS_OK;
1.313 + }
1.314 +
1.315 + // Install a getter/setter pair which will resolve the field onto the actual
1.316 + // object, when invoked.
1.317 +
1.318 + // Get the field name as an id.
1.319 + JS::Rooted<jsid> id(aCx);
1.320 + JS::TwoByteChars chars(mName, NS_strlen(mName));
1.321 + if (!JS_CharsToId(aCx, chars, &id))
1.322 + return NS_ERROR_OUT_OF_MEMORY;
1.323 +
1.324 + // Properties/Methods have historically taken precendence over fields. We
1.325 + // install members first, so just bounce here if the property is already
1.326 + // defined.
1.327 + bool found = false;
1.328 + if (!JS_AlreadyHasOwnPropertyById(aCx, aTargetClassObject, id, &found))
1.329 + return NS_ERROR_FAILURE;
1.330 + if (found)
1.331 + return NS_OK;
1.332 +
1.333 + // FieldGetter and FieldSetter need to run in the XBL scope so that they can
1.334 + // see through any SOWs on their targets.
1.335 +
1.336 + // First, enter the XBL scope, and compile the functions there.
1.337 + JSAutoCompartment ac(aCx, scopeObject);
1.338 + JS::Rooted<JS::Value> wrappedClassObj(aCx, JS::ObjectValue(*aTargetClassObject));
1.339 + if (!JS_WrapValue(aCx, &wrappedClassObj) || !JS_WrapId(aCx, &id))
1.340 + return NS_ERROR_OUT_OF_MEMORY;
1.341 +
1.342 + JS::Rooted<JSObject*> get(aCx,
1.343 + JS_GetFunctionObject(js::NewFunctionByIdWithReserved(aCx, FieldGetter,
1.344 + 0, 0, scopeObject, id)));
1.345 + if (!get) {
1.346 + return NS_ERROR_OUT_OF_MEMORY;
1.347 + }
1.348 + js::SetFunctionNativeReserved(get, XBLPROTO_SLOT, wrappedClassObj);
1.349 + js::SetFunctionNativeReserved(get, FIELD_SLOT,
1.350 + JS::StringValue(JSID_TO_STRING(id)));
1.351 +
1.352 + JS::Rooted<JSObject*> set(aCx,
1.353 + JS_GetFunctionObject(js::NewFunctionByIdWithReserved(aCx, FieldSetter,
1.354 + 1, 0, scopeObject, id)));
1.355 + if (!set) {
1.356 + return NS_ERROR_OUT_OF_MEMORY;
1.357 + }
1.358 + js::SetFunctionNativeReserved(set, XBLPROTO_SLOT, wrappedClassObj);
1.359 + js::SetFunctionNativeReserved(set, FIELD_SLOT,
1.360 + JS::StringValue(JSID_TO_STRING(id)));
1.361 +
1.362 + // Now, re-enter the class object's scope, wrap the getters/setters, and define
1.363 + // them there.
1.364 + JSAutoCompartment ac2(aCx, aTargetClassObject);
1.365 + if (!JS_WrapObject(aCx, &get) || !JS_WrapObject(aCx, &set) ||
1.366 + !JS_WrapId(aCx, &id))
1.367 + {
1.368 + return NS_ERROR_OUT_OF_MEMORY;
1.369 + }
1.370 +
1.371 + if (!::JS_DefinePropertyById(aCx, aTargetClassObject, id, JS::UndefinedValue(),
1.372 + JS_DATA_TO_FUNC_PTR(JSPropertyOp, get.get()),
1.373 + JS_DATA_TO_FUNC_PTR(JSStrictPropertyOp, set.get()),
1.374 + AccessorAttributes())) {
1.375 + return NS_ERROR_OUT_OF_MEMORY;
1.376 + }
1.377 +
1.378 + return NS_OK;
1.379 +}
1.380 +
1.381 +nsresult
1.382 +nsXBLProtoImplField::InstallField(JS::Handle<JSObject*> aBoundNode,
1.383 + nsIURI* aBindingDocURI,
1.384 + bool* aDidInstall) const
1.385 +{
1.386 + NS_PRECONDITION(aBoundNode,
1.387 + "uh-oh, bound node should NOT be null or bad things will "
1.388 + "happen");
1.389 +
1.390 + *aDidInstall = false;
1.391 +
1.392 + // Empty fields are treated as not actually present.
1.393 + if (IsEmpty()) {
1.394 + return NS_OK;
1.395 + }
1.396 +
1.397 + nsAutoMicroTask mt;
1.398 +
1.399 + // EvaluateString and JS_DefineUCProperty can both trigger GC, so
1.400 + // protect |result| here.
1.401 + nsresult rv;
1.402 +
1.403 + nsAutoCString uriSpec;
1.404 + aBindingDocURI->GetSpec(uriSpec);
1.405 +
1.406 + nsIGlobalObject* globalObject = xpc::WindowGlobalOrNull(aBoundNode);
1.407 + if (!globalObject) {
1.408 + return NS_OK;
1.409 + }
1.410 +
1.411 + // We are going to run script via EvaluateString, so we need a script entry
1.412 + // point, but as this is XBL related it does not appear in the HTML spec.
1.413 + AutoEntryScript entryScript(globalObject, true);
1.414 + JSContext* cx = entryScript.cx();
1.415 +
1.416 + NS_ASSERTION(!::JS_IsExceptionPending(cx),
1.417 + "Shouldn't get here when an exception is pending!");
1.418 +
1.419 + // First, enter the xbl scope, wrap the node, and use that as the scope for
1.420 + // the evaluation.
1.421 + JS::Rooted<JSObject*> scopeObject(cx, xpc::GetXBLScopeOrGlobal(cx, aBoundNode));
1.422 + NS_ENSURE_TRUE(scopeObject, NS_ERROR_OUT_OF_MEMORY);
1.423 + JSAutoCompartment ac(cx, scopeObject);
1.424 +
1.425 + JS::Rooted<JSObject*> wrappedNode(cx, aBoundNode);
1.426 + if (!JS_WrapObject(cx, &wrappedNode))
1.427 + return NS_ERROR_OUT_OF_MEMORY;
1.428 +
1.429 + JS::Rooted<JS::Value> result(cx);
1.430 + JS::CompileOptions options(cx);
1.431 + options.setFileAndLine(uriSpec.get(), mLineNumber)
1.432 + .setVersion(JSVERSION_LATEST);
1.433 + nsJSUtils::EvaluateOptions evalOptions;
1.434 + rv = nsJSUtils::EvaluateString(cx, nsDependentString(mFieldText,
1.435 + mFieldTextLength),
1.436 + wrappedNode, options, evalOptions,
1.437 + &result);
1.438 + if (NS_FAILED(rv)) {
1.439 + return rv;
1.440 + }
1.441 +
1.442 +
1.443 + // Now, enter the node's compartment, wrap the eval result, and define it on
1.444 + // the bound node.
1.445 + JSAutoCompartment ac2(cx, aBoundNode);
1.446 + nsDependentString name(mName);
1.447 + if (!JS_WrapValue(cx, &result) ||
1.448 + !::JS_DefineUCProperty(cx, aBoundNode,
1.449 + reinterpret_cast<const jschar*>(mName),
1.450 + name.Length(), result, nullptr, nullptr,
1.451 + mJSAttributes)) {
1.452 + return NS_ERROR_OUT_OF_MEMORY;
1.453 + }
1.454 +
1.455 + *aDidInstall = true;
1.456 + return NS_OK;
1.457 +}
1.458 +
1.459 +nsresult
1.460 +nsXBLProtoImplField::Read(nsIObjectInputStream* aStream)
1.461 +{
1.462 + nsAutoString name;
1.463 + nsresult rv = aStream->ReadString(name);
1.464 + NS_ENSURE_SUCCESS(rv, rv);
1.465 + mName = ToNewUnicode(name);
1.466 +
1.467 + rv = aStream->Read32(&mLineNumber);
1.468 + NS_ENSURE_SUCCESS(rv, rv);
1.469 +
1.470 + nsAutoString fieldText;
1.471 + rv = aStream->ReadString(fieldText);
1.472 + NS_ENSURE_SUCCESS(rv, rv);
1.473 + mFieldTextLength = fieldText.Length();
1.474 + if (mFieldTextLength)
1.475 + mFieldText = ToNewUnicode(fieldText);
1.476 +
1.477 + return NS_OK;
1.478 +}
1.479 +
1.480 +nsresult
1.481 +nsXBLProtoImplField::Write(nsIObjectOutputStream* aStream)
1.482 +{
1.483 + XBLBindingSerializeDetails type = XBLBinding_Serialize_Field;
1.484 +
1.485 + if (mJSAttributes & JSPROP_READONLY) {
1.486 + type |= XBLBinding_Serialize_ReadOnly;
1.487 + }
1.488 +
1.489 + nsresult rv = aStream->Write8(type);
1.490 + NS_ENSURE_SUCCESS(rv, rv);
1.491 + rv = aStream->WriteWStringZ(mName);
1.492 + NS_ENSURE_SUCCESS(rv, rv);
1.493 + rv = aStream->Write32(mLineNumber);
1.494 + NS_ENSURE_SUCCESS(rv, rv);
1.495 +
1.496 + return aStream->WriteWStringZ(mFieldText ? mFieldText : MOZ_UTF16(""));
1.497 +}
