gecko-dev/dom/bindings/BindingUtils.h
Boris Zbarsky e743742df1 Bug 792890. Fix JS-wrapping of callback interfaces to just return the underlying JS object. r=peterv
There are several changes here:

1) When wrapping a callback interface object for JS, just extract the
   underlying JSObject from inside it and hand that object out.

2) Flag callback interface descriptors as "not concrete" (only matters
   for cases when they have constants on the interface object) and not
   wrappercached (will catch bugs if someone tries to treat them as a
   Gecko object).

3) Fix a preexisting bug in sequence wrapping where we'd try to
   JS_DefineElement twice if we were wrapping a null value for a
   sequence of nullable interface objects.
2012-10-10 15:57:57 -04:00

1183 lines
32 KiB
C++

/* -*- 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/. */
#ifndef mozilla_dom_BindingUtils_h__
#define mozilla_dom_BindingUtils_h__
#include "mozilla/dom/DOMJSClass.h"
#include "mozilla/dom/DOMJSProxyHandler.h"
#include "mozilla/dom/NonRefcountedDOMObject.h"
#include "mozilla/dom/workers/Workers.h"
#include "mozilla/ErrorResult.h"
#include "jsapi.h"
#include "jsfriendapi.h"
#include "jswrapper.h"
#include "nsIXPConnect.h"
#include "qsObjectHelper.h"
#include "xpcpublic.h"
#include "nsTraceRefcnt.h"
#include "nsWrapperCacheInlines.h"
#include "mozilla/Likely.h"
// nsGlobalWindow implements nsWrapperCache, but doesn't always use it. Don't
// try to use it without fixing that first.
class nsGlobalWindow;
namespace mozilla {
namespace dom {
enum ErrNum {
#define MSG_DEF(_name, _argc, _str) \
_name,
#include "mozilla/dom/Errors.msg"
#undef MSG_DEF
Err_Limit
};
bool
ThrowErrorMessage(JSContext* aCx, const ErrNum aErrorNumber, ...);
template<bool mainThread>
inline bool
Throw(JSContext* cx, nsresult rv)
{
using mozilla::dom::workers::exceptions::ThrowDOMExceptionForNSResult;
// XXX Introduce exception machinery.
if (mainThread) {
xpc::Throw(cx, rv);
} else {
if (!JS_IsExceptionPending(cx)) {
ThrowDOMExceptionForNSResult(cx, rv);
}
}
return false;
}
template<bool mainThread>
inline bool
ThrowMethodFailedWithDetails(JSContext* cx, const ErrorResult& rv,
const char* /* ifaceName */,
const char* /* memberName */)
{
return Throw<mainThread>(cx, rv.ErrorCode());
}
inline bool
IsDOMClass(const JSClass* clasp)
{
return clasp->flags & JSCLASS_IS_DOMJSCLASS;
}
inline bool
IsDOMClass(const js::Class* clasp)
{
return IsDOMClass(Jsvalify(clasp));
}
// It's ok for eRegularDOMObject and eProxyDOMObject to be the same, but
// eNonDOMObject should always be different from the other two. This enum
// shouldn't be used to differentiate between non-proxy and proxy bindings.
enum DOMObjectSlot {
eNonDOMObject = -1,
eRegularDOMObject = DOM_OBJECT_SLOT,
eProxyDOMObject = DOM_PROXY_OBJECT_SLOT
};
template <class T>
inline T*
UnwrapDOMObject(JSObject* obj, DOMObjectSlot slot)
{
MOZ_ASSERT(slot != eNonDOMObject,
"Don't pass non-DOM objects to this function");
#ifdef DEBUG
if (IsDOMClass(js::GetObjectClass(obj))) {
MOZ_ASSERT(slot == eRegularDOMObject);
} else {
MOZ_ASSERT(js::IsObjectProxyClass(js::GetObjectClass(obj)) ||
js::IsFunctionProxyClass(js::GetObjectClass(obj)));
MOZ_ASSERT(js::GetProxyHandler(obj)->family() == ProxyFamily());
MOZ_ASSERT(IsNewProxyBinding(js::GetProxyHandler(obj)));
MOZ_ASSERT(slot == eProxyDOMObject);
}
#endif
JS::Value val = js::GetReservedSlot(obj, slot);
// XXXbz/khuey worker code tries to unwrap interface objects (which have
// nothing here). That needs to stop.
// XXX We don't null-check UnwrapObject's result; aren't we going to crash
// anyway?
if (val.isUndefined()) {
return NULL;
}
return static_cast<T*>(val.toPrivate());
}
// Only use this with a new DOM binding object (either proxy or regular).
inline const DOMClass*
GetDOMClass(JSObject* obj)
{
js::Class* clasp = js::GetObjectClass(obj);
if (IsDOMClass(clasp)) {
return &DOMJSClass::FromJSClass(clasp)->mClass;
}
js::BaseProxyHandler* handler = js::GetProxyHandler(obj);
MOZ_ASSERT(handler->family() == ProxyFamily());
MOZ_ASSERT(IsNewProxyBinding(handler));
return &static_cast<DOMProxyHandler*>(handler)->mClass;
}
inline DOMObjectSlot
GetDOMClass(JSObject* obj, const DOMClass*& result)
{
js::Class* clasp = js::GetObjectClass(obj);
if (IsDOMClass(clasp)) {
result = &DOMJSClass::FromJSClass(clasp)->mClass;
return eRegularDOMObject;
}
if (js::IsObjectProxyClass(clasp) || js::IsFunctionProxyClass(clasp)) {
js::BaseProxyHandler* handler = js::GetProxyHandler(obj);
if (handler->family() == ProxyFamily() && IsNewProxyBinding(handler)) {
result = &static_cast<DOMProxyHandler*>(handler)->mClass;
return eProxyDOMObject;
}
}
return eNonDOMObject;
}
inline bool
UnwrapDOMObjectToISupports(JSObject* obj, nsISupports*& result)
{
const DOMClass* clasp;
DOMObjectSlot slot = GetDOMClass(obj, clasp);
if (slot == eNonDOMObject || !clasp->mDOMObjectIsISupports) {
return false;
}
result = UnwrapDOMObject<nsISupports>(obj, slot);
return true;
}
inline bool
IsDOMObject(JSObject* obj)
{
js::Class* clasp = js::GetObjectClass(obj);
return IsDOMClass(clasp) ||
((js::IsObjectProxyClass(clasp) || js::IsFunctionProxyClass(clasp)) &&
(js::GetProxyHandler(obj)->family() == ProxyFamily() &&
IsNewProxyBinding(js::GetProxyHandler(obj))));
}
// Some callers don't want to set an exception when unwrapping fails
// (for example, overload resolution uses unwrapping to tell what sort
// of thing it's looking at).
// U must be something that a T* can be assigned to (e.g. T* or an nsRefPtr<T>).
template <prototypes::ID PrototypeID, class T, typename U>
inline nsresult
UnwrapObject(JSContext* cx, JSObject* obj, U& value)
{
/* First check to see whether we have a DOM object */
const DOMClass* domClass;
DOMObjectSlot slot = GetDOMClass(obj, domClass);
if (slot == eNonDOMObject) {
/* Maybe we have a security wrapper or outer window? */
if (!js::IsWrapper(obj)) {
/* Not a DOM object, not a wrapper, just bail */
return NS_ERROR_XPC_BAD_CONVERT_JS;
}
obj = xpc::Unwrap(cx, obj, false);
if (!obj) {
return NS_ERROR_XPC_SECURITY_MANAGER_VETO;
}
MOZ_ASSERT(!js::IsWrapper(obj));
slot = GetDOMClass(obj, domClass);
if (slot == eNonDOMObject) {
/* We don't have a DOM object */
return NS_ERROR_XPC_BAD_CONVERT_JS;
}
}
/* This object is a DOM object. Double-check that it is safely
castable to T by checking whether it claims to inherit from the
class identified by protoID. */
if (domClass->mInterfaceChain[PrototypeTraits<PrototypeID>::Depth] ==
PrototypeID) {
value = UnwrapDOMObject<T>(obj, slot);
return NS_OK;
}
/* It's the wrong sort of DOM object */
return NS_ERROR_XPC_BAD_CONVERT_JS;
}
inline bool
IsArrayLike(JSContext* cx, JSObject* obj)
{
MOZ_ASSERT(obj);
// For simplicity, check for security wrappers up front. In case we
// have a security wrapper, don't forget to enter the compartment of
// the underlying object after unwrapping.
Maybe<JSAutoCompartment> ac;
if (js::IsWrapper(obj)) {
obj = xpc::Unwrap(cx, obj, false);
if (!obj) {
// Let's say it's not
return false;
}
ac.construct(cx, obj);
}
// XXXbz need to detect platform objects (including listbinding
// ones) with indexGetters here!
return JS_IsArrayObject(cx, obj) || JS_IsTypedArrayObject(obj, cx);
}
inline bool
IsPlatformObject(JSContext* cx, JSObject* obj)
{
// XXXbz Should be treating list-binding objects as platform objects
// too? The one consumer so far wants non-array-like platform
// objects, so listbindings that have an indexGetter should test
// false from here. Maybe this function should have a different
// name?
MOZ_ASSERT(obj);
// Fast-path the common case
JSClass* clasp = js::GetObjectJSClass(obj);
if (IsDOMClass(clasp)) {
return true;
}
// Now for simplicity check for security wrappers before anything else
if (js::IsWrapper(obj)) {
obj = xpc::Unwrap(cx, obj, false);
if (!obj) {
// Let's say it's not
return false;
}
clasp = js::GetObjectJSClass(obj);
}
return IS_WRAPPER_CLASS(js::Valueify(clasp)) || IsDOMClass(clasp) ||
JS_IsArrayBufferObject(obj, cx);
}
// U must be something that a T* can be assigned to (e.g. T* or an nsRefPtr<T>).
template <class T, typename U>
inline nsresult
UnwrapObject(JSContext* cx, JSObject* obj, U& value)
{
return UnwrapObject<static_cast<prototypes::ID>(
PrototypeIDMap<T>::PrototypeID), T>(cx, obj, value);
}
const size_t kProtoOrIfaceCacheCount =
prototypes::id::_ID_Count + constructors::id::_ID_Count;
inline void
AllocateProtoOrIfaceCache(JSObject* obj)
{
MOZ_ASSERT(js::GetObjectClass(obj)->flags & JSCLASS_DOM_GLOBAL);
MOZ_ASSERT(js::GetReservedSlot(obj, DOM_PROTOTYPE_SLOT).isUndefined());
// Important: The () at the end ensure zero-initialization
JSObject** protoOrIfaceArray = new JSObject*[kProtoOrIfaceCacheCount]();
js::SetReservedSlot(obj, DOM_PROTOTYPE_SLOT,
JS::PrivateValue(protoOrIfaceArray));
}
inline void
TraceProtoOrIfaceCache(JSTracer* trc, JSObject* obj)
{
MOZ_ASSERT(js::GetObjectClass(obj)->flags & JSCLASS_DOM_GLOBAL);
if (!HasProtoOrIfaceArray(obj))
return;
JSObject** protoOrIfaceArray = GetProtoOrIfaceArray(obj);
for (size_t i = 0; i < kProtoOrIfaceCacheCount; ++i) {
JSObject* proto = protoOrIfaceArray[i];
if (proto) {
JS_CALL_OBJECT_TRACER(trc, proto, "protoOrIfaceArray[i]");
}
}
}
inline void
DestroyProtoOrIfaceCache(JSObject* obj)
{
MOZ_ASSERT(js::GetObjectClass(obj)->flags & JSCLASS_DOM_GLOBAL);
JSObject** protoOrIfaceArray = GetProtoOrIfaceArray(obj);
delete [] protoOrIfaceArray;
}
struct ConstantSpec
{
const char* name;
JS::Value value;
};
/**
* Add constants to an object.
*/
bool
DefineConstants(JSContext* cx, JSObject* obj, ConstantSpec* cs);
template<typename T>
struct Prefable {
// A boolean indicating whether this set of specs is enabled
bool enabled;
// Array of specs, terminated in whatever way is customary for T.
// Null to indicate a end-of-array for Prefable, when such an
// indicator is needed.
T* specs;
};
/*
* Create a DOM interface object (if constructorClass is non-null) and/or a
* DOM interface prototype object (if protoClass is non-null).
*
* global is used as the parent of the interface object and the interface
* prototype object
* receiver is the object on which we need to define the interface object as a
* property
* protoProto is the prototype to use for the interface prototype object.
* protoClass is the JSClass to use for the interface prototype object.
* This is null if we should not create an interface prototype
* object.
* constructorClass is the JSClass to use for the interface object.
* This is null if we should not create an interface object or
* if it should be a function object.
* constructor is the JSNative to use as a constructor. If this is non-null, it
* should be used as a JSNative to back the interface object, which
* should be a Function. If this is null, then we should create an
* object of constructorClass, unless that's also null, in which
* case we should not create an interface object at all.
* ctorNargs is the length of the constructor function; 0 if no constructor
* instanceClass is the JSClass of instance objects for this class. This can
* be null if this is not a concrete proto.
* methods and properties are to be defined on the interface prototype object;
* these arguments are allowed to be null if there are no
* methods or properties respectively.
* constants are to be defined on the interface object and on the interface
* prototype object; allowed to be null if there are no constants.
* staticMethods are to be defined on the interface object; allowed to be null
* if there are no static methods.
*
* At least one of protoClass and constructorClass should be non-null.
* If constructorClass is non-null, the resulting interface object will be
* defined on the given global with property name |name|, which must also be
* non-null.
*
* returns the interface prototype object if protoClass is non-null, else it
* returns the interface object.
*/
JSObject*
CreateInterfaceObjects(JSContext* cx, JSObject* global, JSObject* receiver,
JSObject* protoProto, JSClass* protoClass,
JSClass* constructorClass, JSNative constructor,
unsigned ctorNargs, const DOMClass* domClass,
Prefable<JSFunctionSpec>* methods,
Prefable<JSPropertySpec>* properties,
Prefable<ConstantSpec>* constants,
Prefable<JSFunctionSpec>* staticMethods, const char* name);
template <class T>
inline bool
WrapNewBindingObject(JSContext* cx, JSObject* scope, T* value, JS::Value* vp)
{
JSObject* obj = value->GetWrapper();
if (obj && js::GetObjectCompartment(obj) == js::GetObjectCompartment(scope)) {
*vp = JS::ObjectValue(*obj);
return true;
}
if (!obj) {
bool triedToWrap;
obj = value->WrapObject(cx, scope, &triedToWrap);
if (!obj) {
// At this point, obj is null, so just return false. We could
// try to communicate triedToWrap to the caller, but in practice
// callers seem to be testing JS_IsExceptionPending(cx) to
// figure out whether WrapObject() threw instead.
return false;
}
}
// When called via XrayWrapper, we end up here while running in the
// chrome compartment. But the obj we have would be created in
// whatever the content compartment is. So at this point we need to
// make sure it's correctly wrapped for the compartment of |scope|.
// cx should already be in the compartment of |scope| here.
MOZ_ASSERT(js::IsObjectInContextCompartment(scope, cx));
*vp = JS::ObjectValue(*obj);
return JS_WrapValue(cx, vp);
}
// Helper for smart pointers (nsAutoPtr/nsRefPtr/nsCOMPtr).
template <template <typename> class SmartPtr, class T>
inline bool
WrapNewBindingObject(JSContext* cx, JSObject* scope, const SmartPtr<T>& value,
JS::Value* vp)
{
return WrapNewBindingObject(cx, scope, value.get(), vp);
}
template <class T>
inline bool
WrapNewBindingNonWrapperCachedObject(JSContext* cx, JSObject* scope, T* value,
JS::Value* vp)
{
// We try to wrap in the compartment of the underlying object of "scope"
JSObject* obj;
{
// scope for the JSAutoCompartment so that we restore the compartment
// before we call JS_WrapValue.
Maybe<JSAutoCompartment> ac;
if (js::IsWrapper(scope)) {
scope = xpc::Unwrap(cx, scope, false);
if (!scope)
return false;
ac.construct(cx, scope);
}
obj = value->WrapObject(cx, scope);
}
// We can end up here in all sorts of compartments, per above. Make
// sure to JS_WrapValue!
*vp = JS::ObjectValue(*obj);
return JS_WrapValue(cx, vp);
}
// Helper for smart pointers (nsAutoPtr/nsRefPtr/nsCOMPtr).
template <template <typename> class SmartPtr, typename T>
inline bool
WrapNewBindingNonWrapperCachedObject(JSContext* cx, JSObject* scope,
const SmartPtr<T>& value, JS::Value* vp)
{
return WrapNewBindingNonWrapperCachedObject(cx, scope, value.get(), vp);
}
/**
* A method to handle new-binding wrap failure, by possibly falling back to
* wrapping as a non-new-binding object.
*/
bool
DoHandleNewBindingWrappingFailure(JSContext* cx, JSObject* scope,
nsISupports* value, JS::Value* vp);
/**
* An easy way to call the above when you have a value which
* multiply-inherits from nsISupports.
*/
template <class T>
bool
HandleNewBindingWrappingFailure(JSContext* cx, JSObject* scope, T* value,
JS::Value* vp)
{
nsCOMPtr<nsISupports> val;
CallQueryInterface(value, getter_AddRefs(val));
return DoHandleNewBindingWrappingFailure(cx, scope, val, vp);
}
// Helper for smart pointers (nsAutoPtr/nsRefPtr/nsCOMPtr).
template <template <typename> class SmartPtr, class T>
MOZ_ALWAYS_INLINE bool
HandleNewBindingWrappingFailure(JSContext* cx, JSObject* scope,
const SmartPtr<T>& value, JS::Value* vp)
{
return HandleNewBindingWrappingFailure(cx, scope, value.get(), vp);
}
struct EnumEntry {
const char* value;
size_t length;
};
template<bool Fatal>
inline bool
EnumValueNotFound(JSContext* cx, const jschar* chars, size_t length,
const char* type)
{
return false;
}
template<>
inline bool
EnumValueNotFound<false>(JSContext* cx, const jschar* chars, size_t length,
const char* type)
{
// TODO: Log a warning to the console.
return true;
}
template<>
inline bool
EnumValueNotFound<true>(JSContext* cx, const jschar* chars, size_t length,
const char* type)
{
NS_LossyConvertUTF16toASCII deflated(static_cast<const PRUnichar*>(chars),
length);
return ThrowErrorMessage(cx, MSG_INVALID_ENUM_VALUE, deflated.get(), type);
}
template<bool InvalidValueFatal>
inline int
FindEnumStringIndex(JSContext* cx, JS::Value v, const EnumEntry* values,
const char* type, bool* ok)
{
// JS_StringEqualsAscii is slow as molasses, so don't use it here.
JSString* str = JS_ValueToString(cx, v);
if (!str) {
*ok = false;
return 0;
}
JS::Anchor<JSString*> anchor(str);
size_t length;
const jschar* chars = JS_GetStringCharsAndLength(cx, str, &length);
if (!chars) {
*ok = false;
return 0;
}
int i = 0;
for (const EnumEntry* value = values; value->value; ++value, ++i) {
if (length != value->length) {
continue;
}
bool equal = true;
const char* val = value->value;
for (size_t j = 0; j != length; ++j) {
if (unsigned(val[j]) != unsigned(chars[j])) {
equal = false;
break;
}
}
if (equal) {
*ok = true;
return i;
}
}
*ok = EnumValueNotFound<InvalidValueFatal>(cx, chars, length, type);
return -1;
}
inline nsWrapperCache*
GetWrapperCache(nsWrapperCache* cache)
{
return cache;
}
inline nsWrapperCache*
GetWrapperCache(nsGlobalWindow* not_allowed);
inline nsWrapperCache*
GetWrapperCache(void* p)
{
return NULL;
}
struct ParentObject {
template<class T>
ParentObject(T* aObject) :
mObject(aObject),
mWrapperCache(GetWrapperCache(aObject))
{}
template<class T, template<typename> class SmartPtr>
ParentObject(const SmartPtr<T>& aObject) :
mObject(aObject.get()),
mWrapperCache(GetWrapperCache(aObject.get()))
{}
ParentObject(nsISupports* aObject, nsWrapperCache* aCache) :
mObject(aObject),
mWrapperCache(aCache)
{}
nsISupports* const mObject;
nsWrapperCache* const mWrapperCache;
};
inline nsWrapperCache*
GetWrapperCache(const ParentObject& aParentObject)
{
return aParentObject.mWrapperCache;
}
template<class T>
inline nsISupports*
GetParentPointer(T* aObject)
{
return ToSupports(aObject);
}
inline nsISupports*
GetParentPointer(const ParentObject& aObject)
{
return ToSupports(aObject.mObject);
}
template<class T>
inline void
ClearWrapper(T* p, nsWrapperCache* cache)
{
cache->ClearWrapper();
}
template<class T>
inline void
ClearWrapper(T* p, void*)
{
nsWrapperCache* cache;
CallQueryInterface(p, &cache);
ClearWrapper(p, cache);
}
// Can only be called with the immediate prototype of the instance object. Can
// only be called on the prototype of an object known to be a DOM instance.
JSBool
InstanceClassHasProtoAtDepth(JSHandleObject protoObject, uint32_t protoID,
uint32_t depth);
// 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);
template<class T>
inline bool
WrapObject(JSContext* cx, JSObject* scope, T* p, nsWrapperCache* cache,
const nsIID* iid, JS::Value* vp)
{
if (xpc_FastGetCachedWrapper(cache, scope, vp))
return true;
qsObjectHelper helper(p, cache);
return XPCOMObjectToJsval(cx, scope, helper, iid, true, vp);
}
template<class T>
inline bool
WrapObject(JSContext* cx, JSObject* scope, T* p, const nsIID* iid,
JS::Value* vp)
{
return WrapObject(cx, scope, p, GetWrapperCache(p), iid, vp);
}
template<class T>
inline bool
WrapObject(JSContext* cx, JSObject* scope, T* p, JS::Value* vp)
{
return WrapObject(cx, scope, p, NULL, vp);
}
template<class T>
inline bool
WrapObject(JSContext* cx, JSObject* scope, nsCOMPtr<T> &p, const nsIID* iid,
JS::Value* vp)
{
return WrapObject(cx, scope, p.get(), iid, vp);
}
template<class T>
inline bool
WrapObject(JSContext* cx, JSObject* scope, nsCOMPtr<T> &p, JS::Value* vp)
{
return WrapObject(cx, scope, p, NULL, vp);
}
template<class T>
inline bool
WrapObject(JSContext* cx, JSObject* scope, nsRefPtr<T> &p, const nsIID* iid,
JS::Value* vp)
{
return WrapObject(cx, scope, p.get(), iid, vp);
}
template<class T>
inline bool
WrapObject(JSContext* cx, JSObject* scope, nsRefPtr<T> &p, JS::Value* vp)
{
return WrapObject(cx, scope, p, NULL, vp);
}
template<>
inline bool
WrapObject<JSObject>(JSContext* cx, JSObject* scope, JSObject* p, JS::Value* vp)
{
vp->setObjectOrNull(p);
return true;
}
bool
WrapCallbackInterface(JSContext *cx, JSObject *scope, nsISupports* callback,
JS::Value* vp);
template<typename T>
static inline JSObject*
WrapNativeParent(JSContext* cx, JSObject* scope, const T& p)
{
if (!GetParentPointer(p))
return scope;
nsWrapperCache* cache = GetWrapperCache(p);
JSObject* obj;
if (cache && (obj = cache->GetWrapper())) {
#ifdef DEBUG
qsObjectHelper helper(GetParentPointer(p), cache);
JS::Value debugVal;
bool ok = XPCOMObjectToJsval(cx, scope, helper, NULL, false, &debugVal);
NS_ASSERTION(ok && JSVAL_TO_OBJECT(debugVal) == obj,
"Unexpected object in nsWrapperCache");
#endif
return obj;
}
qsObjectHelper helper(GetParentPointer(p), cache);
JS::Value v;
return XPCOMObjectToJsval(cx, scope, helper, NULL, false, &v) ?
JSVAL_TO_OBJECT(v) :
NULL;
}
static inline bool
InternJSString(JSContext* cx, jsid& id, const char* chars)
{
if (JSString *str = ::JS_InternString(cx, chars)) {
id = INTERNED_STRING_TO_JSID(cx, str);
return true;
}
return false;
}
// Spec needs a name property
template <typename Spec>
static bool
InitIds(JSContext* cx, Prefable<Spec>* prefableSpecs, jsid* ids)
{
MOZ_ASSERT(prefableSpecs);
MOZ_ASSERT(prefableSpecs->specs);
do {
// We ignore whether the set of ids is enabled and just intern all the IDs,
// because this is only done once per application runtime.
Spec* spec = prefableSpecs->specs;
do {
if (!InternJSString(cx, *ids, spec->name)) {
return false;
}
} while (++ids, (++spec)->name);
// We ran out of ids for that pref. Put a JSID_VOID in on the id
// corresponding to the list terminator for the pref.
*ids = JSID_VOID;
++ids;
} while ((++prefableSpecs)->specs);
return true;
}
JSBool
QueryInterface(JSContext* cx, unsigned argc, JS::Value* vp);
JSBool
ThrowingConstructor(JSContext* cx, unsigned argc, JS::Value* vp);
bool
GetPropertyOnPrototype(JSContext* cx, JSObject* proxy, jsid id, bool* found,
JS::Value* vp);
bool
HasPropertyOnPrototype(JSContext* cx, JSObject* proxy, DOMProxyHandler* handler,
jsid id);
template<class T>
class NonNull
{
public:
NonNull()
#ifdef DEBUG
: inited(false)
#endif
{}
operator T&() {
MOZ_ASSERT(inited);
MOZ_ASSERT(ptr, "NonNull<T> was set to null");
return *ptr;
}
operator const T&() const {
MOZ_ASSERT(inited);
MOZ_ASSERT(ptr, "NonNull<T> was set to null");
return *ptr;
}
void operator=(T* t) {
ptr = t;
MOZ_ASSERT(ptr);
#ifdef DEBUG
inited = true;
#endif
}
template<typename U>
void operator=(U* t) {
ptr = t->ToAStringPtr();
MOZ_ASSERT(ptr);
#ifdef DEBUG
inited = true;
#endif
}
T** Slot() {
#ifdef DEBUG
inited = true;
#endif
return &ptr;
}
protected:
T* ptr;
#ifdef DEBUG
bool inited;
#endif
};
template<class T>
class OwningNonNull
{
public:
OwningNonNull()
#ifdef DEBUG
: inited(false)
#endif
{}
operator T&() {
MOZ_ASSERT(inited);
MOZ_ASSERT(ptr, "OwningNonNull<T> was set to null");
return *ptr;
}
void operator=(T* t) {
init(t);
}
void operator=(const already_AddRefed<T>& t) {
init(t);
}
protected:
template<typename U>
void init(U t) {
ptr = t;
MOZ_ASSERT(ptr);
#ifdef DEBUG
inited = true;
#endif
}
nsRefPtr<T> ptr;
#ifdef DEBUG
bool inited;
#endif
};
// A struct that has the same layout as an nsDependentString but much
// faster constructor and destructor behavior
struct FakeDependentString {
FakeDependentString() :
mFlags(nsDependentString::F_TERMINATED)
{
}
void SetData(const nsDependentString::char_type* aData,
nsDependentString::size_type aLength) {
MOZ_ASSERT(mFlags == nsDependentString::F_TERMINATED);
mData = aData;
mLength = aLength;
}
void Truncate() {
mData = nsDependentString::char_traits::sEmptyBuffer;
mLength = 0;
}
void SetNull() {
Truncate();
mFlags |= nsDependentString::F_VOIDED;
}
const nsAString* ToAStringPtr() const {
return reinterpret_cast<const nsDependentString*>(this);
}
nsAString* ToAStringPtr() {
return reinterpret_cast<nsDependentString*>(this);
}
operator const nsAString& () const {
return *reinterpret_cast<const nsDependentString*>(this);
}
private:
const nsDependentString::char_type* mData;
nsDependentString::size_type mLength;
uint32_t mFlags;
// A class to use for our static asserts to ensure our object layout
// matches that of nsDependentString.
class DependentStringAsserter;
friend class DependentStringAsserter;
class DepedentStringAsserter : public nsDependentString {
public:
static void StaticAsserts() {
MOZ_STATIC_ASSERT(sizeof(FakeDependentString) == sizeof(nsDependentString),
"Must have right object size");
MOZ_STATIC_ASSERT(offsetof(FakeDependentString, mData) ==
offsetof(DepedentStringAsserter, mData),
"Offset of mData should match");
MOZ_STATIC_ASSERT(offsetof(FakeDependentString, mLength) ==
offsetof(DepedentStringAsserter, mLength),
"Offset of mLength should match");
MOZ_STATIC_ASSERT(offsetof(FakeDependentString, mFlags) ==
offsetof(DepedentStringAsserter, mFlags),
"Offset of mFlags should match");
}
};
};
enum StringificationBehavior {
eStringify,
eEmpty,
eNull
};
// pval must not be null and must point to a rooted JS::Value
static inline bool
ConvertJSValueToString(JSContext* cx, const JS::Value& v, JS::Value* pval,
StringificationBehavior nullBehavior,
StringificationBehavior undefinedBehavior,
FakeDependentString& result)
{
JSString *s;
if (v.isString()) {
s = v.toString();
} else {
StringificationBehavior behavior;
if (v.isNull()) {
behavior = nullBehavior;
} else if (v.isUndefined()) {
behavior = undefinedBehavior;
} else {
behavior = eStringify;
}
if (behavior != eStringify) {
if (behavior == eEmpty) {
result.Truncate();
} else {
result.SetNull();
}
return true;
}
s = JS_ValueToString(cx, v);
if (!s) {
return false;
}
pval->setString(s); // Root the new string.
}
size_t len;
const jschar *chars = JS_GetStringCharsZAndLength(cx, s, &len);
if (!chars) {
return false;
}
result.SetData(chars, len);
return true;
}
// Class for representing optional arguments.
template<typename T>
class Optional {
public:
Optional() {}
bool WasPassed() const {
return !mImpl.empty();
}
void Construct() {
mImpl.construct();
}
template <class T1, class T2>
void Construct(const T1 &t1, const T2 &t2) {
mImpl.construct(t1, t2);
}
const T& Value() const {
return mImpl.ref();
}
T& Value() {
return mImpl.ref();
}
private:
// Forbid copy-construction and assignment
Optional(const Optional& other) MOZ_DELETE;
const Optional &operator=(const Optional &other) MOZ_DELETE;
Maybe<T> mImpl;
};
// Specialization for strings.
template<>
class Optional<nsAString> {
public:
Optional() : mPassed(false) {}
bool WasPassed() const {
return mPassed;
}
void operator=(const nsAString* str) {
MOZ_ASSERT(str);
mStr = str;
mPassed = true;
}
void operator=(const FakeDependentString* str) {
MOZ_ASSERT(str);
mStr = str->ToAStringPtr();
mPassed = true;
}
const nsAString& Value() const {
MOZ_ASSERT(WasPassed());
return *mStr;
}
private:
// Forbid copy-construction and assignment
Optional(const Optional& other) MOZ_DELETE;
const Optional &operator=(const Optional &other) MOZ_DELETE;
bool mPassed;
const nsAString* mStr;
};
// Class for representing sequences in arguments. We use an auto array that can
// hold 16 elements, to avoid having to allocate in common cases. This needs to
// be fallible because web content controls the length of the array, and can
// easily try to create very large lengths.
template<typename T>
class Sequence : public AutoFallibleTArray<T, 16>
{
public:
Sequence() : AutoFallibleTArray<T, 16>() {}
};
// Class for holding the type of members of a union. The union type has an enum
// to keep track of which of its UnionMembers has been constructed.
template<class T>
class UnionMember {
AlignedStorage2<T> storage;
public:
T& SetValue() {
new (storage.addr()) T();
return *storage.addr();
}
const T& Value() const {
return *storage.addr();
}
void Destroy() {
storage.addr()->~T();
}
};
// Implementation of the bits that XrayWrapper needs
bool
XrayResolveProperty(JSContext* cx, JSObject* wrapper, jsid id,
JSPropertyDescriptor* desc,
// And the things we need to determine the descriptor
Prefable<JSFunctionSpec>* methods,
jsid* methodIds,
JSFunctionSpec* methodSpecs,
size_t methodCount,
Prefable<JSPropertySpec>* attributes,
jsid* attributeIds,
JSPropertySpec* attributeSpecs,
size_t attributeCount,
Prefable<ConstantSpec>* constants,
jsid* constantIds,
ConstantSpec* constantSpecs,
size_t constantCount);
bool
XrayEnumerateProperties(JS::AutoIdVector& props,
Prefable<JSFunctionSpec>* methods,
jsid* methodIds,
JSFunctionSpec* methodSpecs,
size_t methodCount,
Prefable<JSPropertySpec>* attributes,
jsid* attributeIds,
JSPropertySpec* attributeSpecs,
size_t attributeCount,
Prefable<ConstantSpec>* constants,
jsid* constantIds,
ConstantSpec* constantSpecs,
size_t constantCount);
// Transfer reference in ptr to smartPtr.
template<class T>
inline void
Take(nsRefPtr<T>& smartPtr, T* ptr)
{
smartPtr = dont_AddRef(ptr);
}
// Transfer ownership of ptr to smartPtr.
template<class T>
inline void
Take(nsAutoPtr<T>& smartPtr, T* ptr)
{
smartPtr = ptr;
}
inline void
MustInheritFromNonRefcountedDOMObject(NonRefcountedDOMObject*)
{
}
// Set the chain of expando objects for various consumers of the given object.
// For Paris Bindings only. See the relevant infrastructure in XrayWrapper.cpp.
JSObject* GetXrayExpandoChain(JSObject *obj);
void SetXrayExpandoChain(JSObject *obj, JSObject *chain);
} // namespace dom
} // namespace mozilla
#endif /* mozilla_dom_BindingUtils_h__ */