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Utils.cpp
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Utils.cpp
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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
/* vim: set ts=2 sw=2 et tw=79: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "Utils.h"
namespace mozilla {
namespace dom {
namespace bindings {
static bool
DefineConstants(JSContext* cx, JSObject* obj, ConstantSpec* cs)
{
for (; cs->name; ++cs) {
JSBool ok =
JS_DefineProperty(cx, obj, cs->name, cs->value, NULL, NULL,
JSPROP_ENUMERATE | JSPROP_READONLY | JSPROP_PERMANENT);
if (!ok) {
return false;
}
}
return true;
}
// We should use JSFunction objects for interface objects, but we need a custom
// hasInstance hook because we have new interface objects on prototype chains of
// old (XPConnect-based) bindings. Because Function.prototype.toString throws if
// passed a non-Function object we also need to provide our own toString method
// for interface objects.
enum {
TOSTRING_CLASS_RESERVED_SLOT = 0,
TOSTRING_NAME_RESERVED_SLOT = 1
};
JSBool
InterfaceObjectToString(JSContext* cx, unsigned argc, JS::Value *vp)
{
JSObject* callee = JSVAL_TO_OBJECT(JS_CALLEE(cx, vp));
JSObject* obj = JS_THIS_OBJECT(cx, vp);
if (!obj) {
JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL, JSMSG_CANT_CONVERT_TO,
"null", "object");
return false;
}
jsval v = js::GetFunctionNativeReserved(callee, TOSTRING_CLASS_RESERVED_SLOT);
JSClass* clasp = static_cast<JSClass*>(JSVAL_TO_PRIVATE(v));
v = js::GetFunctionNativeReserved(callee, TOSTRING_NAME_RESERVED_SLOT);
JSString* jsname = static_cast<JSString*>(JSVAL_TO_STRING(v));
size_t length;
const jschar* name = JS_GetInternedStringCharsAndLength(jsname, &length);
if (js::GetObjectJSClass(obj) != clasp) {
JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL, JSMSG_INCOMPATIBLE_PROTO,
NS_ConvertUTF16toUTF8(name).get(), "toString",
"object");
return false;
}
JS::Value* argv = JS_ARGV(cx, vp);
uint32_t indent = 0;
if (argc != 0 && !JS_ValueToECMAUint32(cx, argv[0], &indent))
return false;
nsAutoString spaces;
while (indent-- > 0) {
spaces.Append(PRUnichar(' '));
}
nsString str;
str.Append(spaces);
str.AppendLiteral("function ");
str.Append(name, length);
str.AppendLiteral("() {");
str.Append('\n');
str.Append(spaces);
str.AppendLiteral(" [native code]");
str.Append('\n');
str.Append(spaces);
str.AppendLiteral("}");
return xpc::NonVoidStringToJsval(cx, str, vp);
}
static JSObject*
CreateInterfaceObject(JSContext* cx, JSObject* global, JSObject* receiver,
JSClass* constructorClass, JSNative constructorNative,
unsigned ctorNargs, JSObject* proto,
JSFunctionSpec* staticMethods, ConstantSpec* constants,
const char* name)
{
JSObject* constructor;
if (constructorClass) {
JSObject* functionProto = JS_GetFunctionPrototype(cx, global);
if (!functionProto) {
return NULL;
}
constructor = JS_NewObject(cx, constructorClass, functionProto, global);
} else {
MOZ_ASSERT(constructorNative);
JSFunction* fun = JS_NewFunction(cx, constructorNative, ctorNargs,
JSFUN_CONSTRUCTOR, global, name);
if (!fun) {
return NULL;
}
constructor = JS_GetFunctionObject(fun);
}
if (!constructor) {
return NULL;
}
if (staticMethods && !JS_DefineFunctions(cx, constructor, staticMethods)) {
return NULL;
}
if (constructorClass) {
JSFunction* toString = js::DefineFunctionWithReserved(cx, constructor,
"toString",
InterfaceObjectToString,
0, 0);
if (!toString) {
return NULL;
}
JSObject* toStringObj = JS_GetFunctionObject(toString);
js::SetFunctionNativeReserved(toStringObj, TOSTRING_CLASS_RESERVED_SLOT,
PRIVATE_TO_JSVAL(constructorClass));
JSString *str = ::JS_InternString(cx, name);
if (!str) {
return NULL;
}
js::SetFunctionNativeReserved(toStringObj, TOSTRING_NAME_RESERVED_SLOT,
STRING_TO_JSVAL(str));
}
if (constants && !DefineConstants(cx, constructor, constants)) {
return NULL;
}
if (proto && !JS_LinkConstructorAndPrototype(cx, constructor, proto)) {
return NULL;
}
JSBool alreadyDefined;
if (!JS_AlreadyHasOwnProperty(cx, receiver, name, &alreadyDefined)) {
return NULL;
}
// This is Enumerable: False per spec.
if (!alreadyDefined &&
!JS_DefineProperty(cx, receiver, name, OBJECT_TO_JSVAL(constructor), NULL,
NULL, 0)) {
return NULL;
}
return constructor;
}
static JSObject*
CreateInterfacePrototypeObject(JSContext* cx, JSObject* global,
JSObject* parentProto, JSClass* protoClass,
JSFunctionSpec* methods,
JSPropertySpec* properties,
ConstantSpec* constants)
{
JSObject* ourProto = JS_NewObject(cx, protoClass, parentProto, global);
if (!ourProto) {
return NULL;
}
if (methods && !JS_DefineFunctions(cx, ourProto, methods)) {
return NULL;
}
if (properties && !JS_DefineProperties(cx, ourProto, properties)) {
return NULL;
}
if (constants && !DefineConstants(cx, ourProto, constants)) {
return NULL;
}
return ourProto;
}
JSObject*
CreateInterfaceObjects(JSContext* cx, JSObject* global, JSObject *receiver,
JSObject* protoProto, JSClass* protoClass,
JSClass* constructorClass, JSNative constructor,
unsigned ctorNargs, JSFunctionSpec* methods,
JSPropertySpec* properties, ConstantSpec* constants,
JSFunctionSpec* staticMethods, const char* name)
{
MOZ_ASSERT(protoClass || constructorClass || constructor,
"Need at least one class or a constructor!");
MOZ_ASSERT(!(methods || properties) || protoClass,
"Methods or properties but no protoClass!");
MOZ_ASSERT(!staticMethods || (constructorClass || constructor),
"Static methods but no constructorClass!");
MOZ_ASSERT(bool(name) == bool(constructorClass || constructor),
"Must have name precisely when we have an interface object");
MOZ_ASSERT(!constructorClass || !constructor);
JSObject* proto;
if (protoClass) {
proto = CreateInterfacePrototypeObject(cx, global, protoProto, protoClass,
methods, properties, constants);
if (!proto) {
return NULL;
}
}
else {
proto = NULL;
}
JSObject* interface;
if (constructorClass || constructor) {
interface = CreateInterfaceObject(cx, global, receiver, constructorClass,
constructor, ctorNargs, proto,
staticMethods, constants, name);
if (!interface) {
return NULL;
}
}
return protoClass ? proto : interface;
}
static bool
NativeInterface2JSObjectAndThrowIfFailed(XPCLazyCallContext& aLccx,
JSContext* aCx,
JS::Value* aRetval,
xpcObjectHelper& aHelper,
const nsIID* aIID,
bool aAllowNativeWrapper)
{
nsresult rv;
if (!XPCConvert::NativeInterface2JSObject(aLccx, aRetval, NULL, aHelper, aIID,
NULL, aAllowNativeWrapper, &rv)) {
// I can't tell if NativeInterface2JSObject throws JS exceptions
// or not. This is a sloppy stab at the right semantics; the
// method really ought to be fixed to behave consistently.
if (!JS_IsExceptionPending(aCx)) {
Throw<true>(aCx, NS_FAILED(rv) ? rv : NS_ERROR_UNEXPECTED);
}
return false;
}
return true;
}
bool
DoHandleNewBindingWrappingFailure(JSContext* cx, JSObject* scope,
nsISupports* value, JS::Value* vp)
{
if (JS_IsExceptionPending(cx)) {
return false;
}
XPCLazyCallContext lccx(JS_CALLER, cx, scope);
if (value) {
xpcObjectHelper helper(value);
return NativeInterface2JSObjectAndThrowIfFailed(lccx, cx, vp, helper, NULL,
true);
}
return Throw<true>(cx, NS_ERROR_XPC_BAD_CONVERT_JS);
}
// Only set allowNativeWrapper to false if you really know you need it, if in
// doubt use true. Setting it to false disables security wrappers.
bool
XPCOMObjectToJsval(JSContext* cx, JSObject* scope, xpcObjectHelper &helper,
const nsIID* iid, bool allowNativeWrapper, JS::Value* rval)
{
XPCLazyCallContext lccx(JS_CALLER, cx, scope);
if (!NativeInterface2JSObjectAndThrowIfFailed(lccx, cx, rval, helper, iid,
allowNativeWrapper)) {
return false;
}
#ifdef DEBUG
JSObject* jsobj = JSVAL_TO_OBJECT(*rval);
if (jsobj && !js::GetObjectParent(jsobj))
NS_ASSERTION(js::GetObjectClass(jsobj)->flags & JSCLASS_IS_GLOBAL,
"Why did we recreate this wrapper?");
#endif
return true;
}
JSBool
QueryInterface(JSContext* cx, unsigned argc, JS::Value* vp)
{
JS::Value thisv = JS_THIS(cx, vp);
if (thisv == JSVAL_NULL)
return false;
JSObject* obj = JSVAL_TO_OBJECT(thisv);
JSClass* clasp = js::GetObjectJSClass(obj);
if (!IsDOMClass(clasp)) {
return Throw<true>(cx, NS_ERROR_FAILURE);
}
nsISupports* native = UnwrapDOMObject<nsISupports>(obj, clasp);
if (argc < 1) {
return Throw<true>(cx, NS_ERROR_XPC_NOT_ENOUGH_ARGS);
}
JS::Value* argv = JS_ARGV(cx, vp);
if (!argv[0].isObject()) {
return Throw<true>(cx, NS_ERROR_XPC_BAD_CONVERT_JS);
}
nsIJSIID* iid;
xpc_qsSelfRef iidRef;
if (NS_FAILED(xpc_qsUnwrapArg<nsIJSIID>(cx, argv[0], &iid, &iidRef.ptr,
&argv[0]))) {
return Throw<true>(cx, NS_ERROR_XPC_BAD_CONVERT_JS);
}
MOZ_ASSERT(iid);
if (iid->GetID()->Equals(NS_GET_IID(nsIClassInfo))) {
nsresult rv;
nsCOMPtr<nsIClassInfo> ci = do_QueryInterface(native, &rv);
if (NS_FAILED(rv)) {
return Throw<true>(cx, rv);
}
return WrapObject(cx, obj, ci, &NS_GET_IID(nsIClassInfo), vp);
}
// Lie, otherwise we need to check classinfo or QI
*vp = thisv;
return true;
}
JSBool
ThrowingConstructor(JSContext* cx, unsigned argc, JS::Value* vp)
{
return Throw<true>(cx, NS_ERROR_FAILURE);
}
JSBool
ThrowingConstructorWorkers(JSContext* cx, unsigned argc, JS::Value* vp)
{
return Throw<false>(cx, NS_ERROR_FAILURE);
}
} // namespace bindings
} // namespace dom
} // namespace mozilla