/**
 * Get the interface name and member name (for error messages).
 *
 * We could instead have each quick stub pass its name to the error-handling
 * functions, as that name is statically known.  But that would be redundant;
 * the information is handy at runtime anyway.  Also, this code often produces
 * a more specific error message, e.g. "[nsIDOMHTMLDocument.appendChild]"
 * rather than "[nsIDOMNode.appendChild]".
 */
static void
GetMemberInfo(JSObject *obj, jsid memberId, const char **ifaceName)
{
    *ifaceName = "Unknown";

    // Don't try to generate a useful name if there are security wrappers,
    // because it isn't worth the risk of something going wrong just to generate
    // an error message. Instead, only handle the simple case where we have the
    // reflector in hand.
    if (IS_WRAPPER_CLASS(js::GetObjectClass(obj))) {
        XPCWrappedNativeProto *proto;
        if (IS_SLIM_WRAPPER_OBJECT(obj)) {
            proto = GetSlimWrapperProto(obj);
        } else {
            MOZ_ASSERT(IS_WN_WRAPPER_OBJECT(obj));
            XPCWrappedNative *wrapper =
                static_cast<XPCWrappedNative *>(js::GetObjectPrivate(obj));
            proto = wrapper->GetProto();
        }
        if (proto) {
            XPCNativeSet *set = proto->GetSet();
            if (set) {
                XPCNativeMember *member;
                XPCNativeInterface *iface;

                if (set->FindMember(memberId, &member, &iface))
                    *ifaceName = iface->GetNameString();
            }
        }
    }
}

static bool
XPC_WN_Shared_Proto_Enumerate(JSContext* cx, HandleObject obj)
{
    MOZ_ASSERT(js::GetObjectClass(obj) == &XPC_WN_ModsAllowed_Proto_JSClass ||
               js::GetObjectClass(obj) == &XPC_WN_NoMods_Proto_JSClass,
               "bad proto");
    XPCWrappedNativeProto* self =
        (XPCWrappedNativeProto*) xpc_GetJSPrivate(obj);
    if (!self)
        return false;

    XPCNativeSet* set = self->GetSet();
    if (!set)
        return false;

    XPCCallContext ccx(cx);
    if (!ccx.IsValid())
        return false;

    uint16_t interface_count = set->GetInterfaceCount();
    XPCNativeInterface** interfaceArray = set->GetInterfaceArray();
    for (uint16_t i = 0; i < interface_count; i++) {
        XPCNativeInterface* iface = interfaceArray[i];
        uint16_t member_count = iface->GetMemberCount();

        for (uint16_t k = 0; k < member_count; k++) {
            if (!xpc_ForcePropertyResolve(cx, obj, iface->GetMemberAt(k)->GetName()))
                return false;
        }
    }

    return true;
}

NativeUnMarkedSetRemover(JSDHashTable *table, JSDHashEntryHdr *hdr,
                         uint32 number, void *arg)
{
    XPCNativeSet* set = ((ClassInfo2NativeSetMap::Entry*)hdr)->value;
    if(set->IsMarked())
        return JS_DHASH_NEXT;
    return JS_DHASH_REMOVE;
}

// static
XPCNativeSet*
XPCNativeSet::GetNewOrUsed(XPCCallContext& ccx,
                           XPCNativeSet* firstSet,
                           XPCNativeSet* secondSet,
                           bool preserveFirstSetOrder)
{
    // Figure out how many interfaces we'll need in the new set.
    PRUint32 uniqueCount = firstSet->mInterfaceCount;
    for (PRUint32 i = 0; i < secondSet->mInterfaceCount; ++i) {
        if (!firstSet->HasInterface(secondSet->mInterfaces[i]))
            uniqueCount++;
    }

    // If everything in secondSet was a duplicate, we can just use the first
    // set.
    if (uniqueCount == firstSet->mInterfaceCount)
        return firstSet;

    // If the secondSet is just a superset of the first, we can use it provided
    // that the caller doesn't care about ordering.
    if (!preserveFirstSetOrder && uniqueCount == secondSet->mInterfaceCount)
        return secondSet;

    // Ok, darn. Now we have to make a new set.
    //
    // It would be faster to just create the new set all at once, but that
    // would involve wrangling with some pretty hairy code - especially since
    // a lot of stuff assumes that sets are created by adding one interface to an
    // existing set. So let's just do the slow and easy thing and hope that the
    // above optimizations handle the common cases.
    XPCNativeSet* currentSet = firstSet;
    for (PRUint32 i = 0; i < secondSet->mInterfaceCount; ++i) {
        XPCNativeInterface* iface = secondSet->mInterfaces[i];
        if (!currentSet->HasInterface(iface)) {
            // Create a new augmented set, inserting this interface at the end.
            PRUint32 pos = currentSet->mInterfaceCount;
            currentSet = XPCNativeSet::GetNewOrUsed(ccx, currentSet, iface, pos);
            if (!currentSet)
                return nsnull;
        }
    }

    // We've got the union set. Hand it back to the caller.
    MOZ_ASSERT(currentSet->mInterfaceCount == uniqueCount);
    return currentSet;
}

/**
 * Get the interface name and member name (for error messages).
 *
 * We could instead have each quick stub pass its name to the error-handling
 * functions, as that name is statically known.  But that would be redundant;
 * the information is handy at runtime anyway.  Also, this code often produces
 * a more specific error message, e.g. "[nsIDOMHTMLDocument.appendChild]"
 * rather than "[nsIDOMNode.appendChild]".
 */
static void
GetMemberInfo(JSObject *obj,
              jsval memberId,
              const char **ifaceName,
              const char **memberName)
{
    // Get the interface name.  From DefinePropertyIfFound (in
    // xpcwrappednativejsops.cpp) and XPCThrower::Verbosify.
    //
    // We could instead make the quick stub could pass in its interface name,
    // but this code often produces a more specific error message, e.g.
    *ifaceName = "Unknown";

    NS_ASSERTION(IS_WRAPPER_CLASS(STOBJ_GET_CLASS(obj)) ||
                 STOBJ_GET_CLASS(obj) == &XPC_WN_Tearoff_JSClass ||
                 IS_SLIM_WRAPPER(obj),
                 "obj must be a wrapper");
    XPCWrappedNativeProto *proto;
    if(IS_SLIM_WRAPPER(obj))
    {
        proto = GetSlimWrapperProto(obj);
    }
    else
    {
        XPCWrappedNative *wrapper = (XPCWrappedNative *) obj->getPrivate();
        proto = wrapper->GetProto();
    }
    if(proto)
    {
        XPCNativeSet *set = proto->GetSet();
        if(set)
        {
            XPCNativeMember *member;
            XPCNativeInterface *iface;

            if(set->FindMember(memberId, &member, &iface))
                *ifaceName = iface->GetNameString();
        }
    }

    *memberName = (JSVAL_IS_STRING(memberId)
                   ? JS_GetStringBytes(JSVAL_TO_STRING(memberId))
                   : "unknown");
}

bool
NativeSetMap::Entry::Match(const PLDHashEntryHdr* entry, const void* key)
{
    auto Key = static_cast<const XPCNativeSetKey*>(key);
    XPCNativeSet*       SetInTable = ((Entry*)entry)->key_value;
    XPCNativeSet*       Set        = Key->GetBaseSet();
    XPCNativeInterface* Addition   = Key->GetAddition();

    if (!Set) {
        // This is a special case to deal with the invariant that says:
        // "All sets have exactly one nsISupports interface and it comes first."
        // See XPCNativeSet::NewInstance for details.
        //
        // Though we might have a key that represents only one interface, we
        // know that if that one interface were contructed into a set then
        // it would end up really being a set with two interfaces (except for
        // the case where the one interface happened to be nsISupports).

        return (SetInTable->GetInterfaceCount() == 1 &&
                SetInTable->GetInterfaceAt(0) == Addition) ||
               (SetInTable->GetInterfaceCount() == 2 &&
                SetInTable->GetInterfaceAt(1) == Addition);
    }

    if (!Addition && Set == SetInTable)
        return true;

    uint16_t count = Set->GetInterfaceCount();
    if (count + (Addition ? 1 : 0) != SetInTable->GetInterfaceCount())
        return false;

    XPCNativeInterface** CurrentInTable = SetInTable->GetInterfaceArray();
    XPCNativeInterface** Current = Set->GetInterfaceArray();
    for (uint16_t i = 0; i < count; i++) {
        if (*(Current++) != *(CurrentInTable++))
            return false;
    }
    return !Addition || Addition == *(CurrentInTable++);
}

NativeSetSweeper(JSDHashTable *table, JSDHashEntryHdr *hdr,
                 uint32 number, void *arg)
{
    XPCNativeSet* set = ((NativeSetMap::Entry*)hdr)->key_value;
    if(set->IsMarked())
    {
        set->Unmark();
        return JS_DHASH_NEXT;
    }

#ifdef XPC_REPORT_NATIVE_INTERFACE_AND_SET_FLUSHING
    printf("- Destroying XPCNativeSet for:\n");
    PRUint16 count = set->GetInterfaceCount();
    for(PRUint16 k = 0; k < count; k++)
    {
        XPCNativeInterface* iface = set->GetInterfaceAt(k);
        printf("    %s\n",JS_GetStringBytes(JSVAL_TO_STRING(iface->GetName())));
    }
#endif

    XPCNativeSet::DestroyInstance(set);
    return JS_DHASH_REMOVE;
}

/**
 * Get the interface name and member name (for error messages).
 *
 * We could instead have each quick stub pass its name to the error-handling
 * functions, as that name is statically known.  But that would be redundant;
 * the information is handy at runtime anyway.  Also, this code often produces
 * a more specific error message, e.g. "[nsIDOMHTMLDocument.appendChild]"
 * rather than "[nsIDOMNode.appendChild]".
 */
static void
GetMemberInfo(JSObject *obj, jsid memberId, const char **ifaceName)
{
    *ifaceName = "Unknown";

    // Don't try to generate a useful name if there are security wrappers,
    // because it isn't worth the risk of something going wrong just to generate
    // an error message. Instead, only handle the simple case where we have the
    // reflector in hand.
    if (IS_WN_REFLECTOR(obj)) {
        XPCWrappedNative *wrapper = XPCWrappedNative::Get(obj);
        XPCWrappedNativeProto *proto = wrapper->GetProto();
        if (proto) {
            XPCNativeSet *set = proto->GetSet();
            if (set) {
                XPCNativeMember *member;
                XPCNativeInterface *iface;

                if (set->FindMember(memberId, &member, &iface))
                    *ifaceName = iface->GetNameString();
            }
        }
    }
}

bool
XPC_WN_Shared_Enumerate(JSContext* cx, HandleObject obj)
{
    XPCCallContext ccx(cx, obj);
    XPCWrappedNative* wrapper = ccx.GetWrapper();
    THROW_AND_RETURN_IF_BAD_WRAPPER(cx, wrapper);

    // Since we aren't going to enumerate tearoff names and the prototype
    // handles non-mutated members, we can do this potential short-circuit.
    if (!wrapper->HasMutatedSet())
        return true;

    XPCNativeSet* set = wrapper->GetSet();
    XPCNativeSet* protoSet = wrapper->HasProto() ?
                                wrapper->GetProto()->GetSet() : nullptr;

    uint16_t interface_count = set->GetInterfaceCount();
    XPCNativeInterface** interfaceArray = set->GetInterfaceArray();
    for (uint16_t i = 0; i < interface_count; i++) {
        XPCNativeInterface* iface = interfaceArray[i];
        uint16_t member_count = iface->GetMemberCount();
        for (uint16_t k = 0; k < member_count; k++) {
            XPCNativeMember* member = iface->GetMemberAt(k);
            jsid name = member->GetName();

            // Skip if this member is going to come from the proto.
            uint16_t index;
            if (protoSet &&
                protoSet->FindMember(name, nullptr, &index) && index == i)
                continue;
            if (!xpc_ForcePropertyResolve(cx, obj, name))
                return false;
        }
    }
    return true;
}

//.........这里部分代码省略.........
                // chance that a wrapper's set will change *while* a call is
                // happening which uses that wrapper's old interfface set. So,
                // we need to do this marking to avoid collecting those sets
                // that might no longer be otherwise reachable from the wrappers
                // or the wrapperprotos.

                // Skip this part if XPConnect is shutting down. We get into
                // bad locking problems with the thread iteration otherwise.
                if(!self->GetXPConnect()->IsShuttingDown())
                {
                    PRLock* threadLock = XPCPerThreadData::GetLock();
                    if(threadLock)
                    { // scoped lock
                        nsAutoLock lock(threadLock);

                        XPCPerThreadData* iterp = nsnull;
                        XPCPerThreadData* thread;

                        while(nsnull != (thread =
                                     XPCPerThreadData::IterateThreads(&iterp)))
                        {
                            // Mark those AutoMarkingPtr lists!
                            thread->MarkAutoRootsAfterJSFinalize();

                            XPCCallContext* ccxp = thread->GetCallContext();
                            while(ccxp)
                            {
                                // Deal with the strictness of callcontext that
                                // complains if you ask for a set when
                                // it is in a state where the set could not
                                // possibly be valid.
                                if(ccxp->CanGetSet())
                                {
                                    XPCNativeSet* set = ccxp->GetSet();
                                    if(set)
                                        set->Mark();
                                }
                                if(ccxp->CanGetInterface())
                                {
                                    XPCNativeInterface* iface = ccxp->GetInterface();
                                    if(iface)
                                        iface->Mark();
                                }
                                ccxp = ccxp->GetPrevCallContext();
                            }
                        }
                    }
                }

                // Do the sweeping...

                // We don't want to sweep the JSClasses at shutdown time.
                // At this point there may be JSObjects using them that have
                // been removed from the other maps.
                if(!self->GetXPConnect()->IsShuttingDown())
                {
                    self->mNativeScriptableSharedMap->
                        Enumerate(JSClassSweeper, nsnull);
                }

                self->mClassInfo2NativeSetMap->
                    Enumerate(NativeUnMarkedSetRemover, nsnull);

                self->mNativeSetMap->
                    Enumerate(NativeSetSweeper, nsnull);

bool
XPC_WN_Helper_Resolve(JSContext* cx, HandleObject obj, HandleId id, bool* resolvedp)
{
    nsresult rv = NS_OK;
    bool retval = true;
    bool resolved = false;
    XPCCallContext ccx(cx, obj);
    XPCWrappedNative* wrapper = ccx.GetWrapper();
    THROW_AND_RETURN_IF_BAD_WRAPPER(cx, wrapper);

    RootedId old(cx, ccx.SetResolveName(id));

    XPCNativeScriptableInfo* si = wrapper->GetScriptableInfo();
    if (si && si->GetFlags().WantResolve()) {
        XPCWrappedNative* oldResolvingWrapper;
        bool allowPropMods = si->GetFlags().AllowPropModsDuringResolve();

        if (allowPropMods)
            oldResolvingWrapper = ccx.SetResolvingWrapper(wrapper);

        rv = si->GetCallback()->Resolve(wrapper, cx, obj, id, &resolved, &retval);

        if (allowPropMods)
            (void)ccx.SetResolvingWrapper(oldResolvingWrapper);
    }

    old = ccx.SetResolveName(old);
    MOZ_ASSERT(old == id, "bad nest");

    if (NS_FAILED(rv)) {
        return Throw(rv, cx);
    }

    if (resolved) {
        *resolvedp = true;
    } else if (wrapper->HasMutatedSet()) {
        // We are here if scriptable did not resolve this property and
        // it *might* be in the instance set but not the proto set.

        XPCNativeSet* set = wrapper->GetSet();
        XPCNativeSet* protoSet = wrapper->HasProto() ?
                                    wrapper->GetProto()->GetSet() : nullptr;
        XPCNativeMember* member = nullptr;
        RefPtr<XPCNativeInterface> iface;
        bool IsLocal = false;

        if (set->FindMember(id, &member, &iface, protoSet, &IsLocal) &&
            IsLocal) {
            XPCWrappedNative* oldResolvingWrapper;

            XPCNativeScriptableFlags siFlags(0);
            if (si)
                siFlags = si->GetFlags();

            XPCWrappedNative* wrapperForInterfaceNames =
                siFlags.DontReflectInterfaceNames() ? nullptr : wrapper;

            oldResolvingWrapper = ccx.SetResolvingWrapper(wrapper);
            retval = DefinePropertyIfFound(ccx, obj, id,
                                           set, iface, member,
                                           wrapper->GetScope(),
                                           false,
                                           wrapperForInterfaceNames,
                                           nullptr, si,
                                           JSPROP_ENUMERATE, resolvedp);
            (void)ccx.SetResolvingWrapper(oldResolvingWrapper);
        }
    }

    return retval;
}