The Tor Browser: js/xpconnect/src/XPCJSID.cpp@129ffea94266 (annotated)

js/xpconnect/src/XPCJSID.cpp@129ffea94266 (annotated)

js/xpconnect/src/XPCJSID.cpp

Sat, 03 Jan 2015 20:18:00 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Sat, 03 Jan 2015 20:18:00 +0100
branch: TOR_BUG_3246
changeset 7: 129ffea94266
permissions: -rw-r--r--

Conditionally enable double key logic according to:
private browsing mode or privacy.thirdparty.isolate preference and
implement in GetCookieStringCommon and FindCookie where it counts...
With some reservations of how to convince FindCookie users to test
condition and pass a nullptr when disabling double key logic.

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
 /* vim: set ts=8 sts=4 et sw=4 tw=99: */
 /* 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/. */
 /* An xpcom implementation of the JavaScript nsIID and nsCID objects. */
 #include "xpcprivate.h"
 #include "mozilla/dom/BindingUtils.h"
 #include "mozilla/Attributes.h"
 #include "JavaScriptParent.h"
 #include "mozilla/StaticPtr.h"
 using namespace mozilla::dom;
 using namespace JS;
 /***************************************************************************/
 // nsJSID
 NS_IMPL_CLASSINFO(nsJSID, nullptr, 0, NS_JS_ID_CID)
 NS_IMPL_ISUPPORTS_CI(nsJSID, nsIJSID)
 char nsJSID::gNoString[] = "";
 nsJSID::nsJSID()
     : mID(GetInvalidIID()), mNumber(gNoString), mName(gNoString)
 {
 }
 nsJSID::~nsJSID()
 {
     if (mNumber && mNumber != gNoString)
         NS_Free(mNumber);
     if (mName && mName != gNoString)
         NS_Free(mName);
 }
 void nsJSID::Reset()
 {
     mID = GetInvalidIID();
     if (mNumber && mNumber != gNoString)
         NS_Free(mNumber);
     if (mName && mName != gNoString)
         NS_Free(mName);
     mNumber = mName = nullptr;
 }
 bool
 nsJSID::SetName(const char* name)
 {
     MOZ_ASSERT(!mName || mName == gNoString ,"name already set");
     MOZ_ASSERT(name,"null name");
     mName = NS_strdup(name);
     return mName ? true : false;
 }
 NS_IMETHODIMP
 nsJSID::GetName(char * *aName)
 {
     if (!aName)
         return NS_ERROR_NULL_POINTER;
     if (!NameIsSet())
         SetNameToNoString();
     MOZ_ASSERT(mName, "name not set");
     *aName = NS_strdup(mName);
     return *aName ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
 }
 NS_IMETHODIMP
 nsJSID::GetNumber(char * *aNumber)
 {
     if (!aNumber)
         return NS_ERROR_NULL_POINTER;
     if (!mNumber) {
         if (!(mNumber = mID.ToString()))
             mNumber = gNoString;
     }
     *aNumber = NS_strdup(mNumber);
     return *aNumber ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
 }
 NS_IMETHODIMP_(const nsID*)
 nsJSID::GetID()
 {
     return &mID;
 }
 NS_IMETHODIMP
 nsJSID::GetValid(bool *aValid)
 {
     if (!aValid)
         return NS_ERROR_NULL_POINTER;
     *aValid = IsValid();
     return NS_OK;
 }
 NS_IMETHODIMP
 nsJSID::Equals(nsIJSID *other, bool *_retval)
 {
     if (!_retval)
         return NS_ERROR_NULL_POINTER;
     if (!other || mID.Equals(GetInvalidIID())) {
         *_retval = false;
         return NS_OK;
     }
     *_retval = other->GetID()->Equals(mID);
     return NS_OK;
 }
 NS_IMETHODIMP
 nsJSID::Initialize(const char *idString)
 {
     if (!idString)
         return NS_ERROR_NULL_POINTER;
     if (*idString != '\0' && mID.Equals(GetInvalidIID())) {
         Reset();
         if (idString[0] == '{') {
             if (mID.Parse(idString)) {
                 return NS_OK;
             }
             // error - reset to invalid state
             mID = GetInvalidIID();
         }
     }
     return NS_ERROR_FAILURE;
 }
 bool
 nsJSID::InitWithName(const nsID& id, const char *nameString)
 {
     MOZ_ASSERT(nameString, "no name");
     Reset();
     mID = id;
     return SetName(nameString);
 }
 // try to use the name, if no name, then use the number
 NS_IMETHODIMP
 nsJSID::ToString(char **_retval)
 {
     if (mName && mName != gNoString)
         return GetName(_retval);
     return GetNumber(_retval);
 }
 const nsID&
 nsJSID::GetInvalidIID() const
 {
     // {BB1F47B0-D137-11d2-9841-006008962422}
     static const nsID invalid = {0xbb1f47b0, 0xd137, 0x11d2,
                                   {0x98, 0x41, 0x0, 0x60, 0x8, 0x96, 0x24, 0x22}};
     return invalid;
 }
 //static
 already_AddRefed<nsJSID>
 nsJSID::NewID(const char* str)
 {
     if (!str) {
         NS_ERROR("no string");
         return nullptr;
     }
     nsRefPtr<nsJSID> idObj = new nsJSID();
     NS_ENSURE_SUCCESS(idObj->Initialize(str), nullptr);
     return idObj.forget();
 }
 //static
 already_AddRefed<nsJSID>
 nsJSID::NewID(const nsID& id)
 {
     nsRefPtr<nsJSID> idObj = new nsJSID();
     idObj->mID = id;
     idObj->mName = nullptr;
     idObj->mNumber = nullptr;
     return idObj.forget();
 }
 /***************************************************************************/
 // Class object support so that we can share prototypes of wrapper
 // This class exists just so we can have a shared scriptable helper for
 // the nsJSIID class. The instances implement their own helpers. But we
 // needed to be able to indicate to the shared prototypes this single flag:
 // nsIXPCScriptable::DONT_ENUM_STATIC_PROPS. And having a class to do it is
 // the only means we have. Setting this flag on any given instance scriptable
 // helper is not sufficient to convey the information that we don't want
 // static properties enumerated on the shared proto.
 class SharedScriptableHelperForJSIID MOZ_FINAL : public nsIXPCScriptable
 {
 public:
     NS_DECL_ISUPPORTS
     NS_DECL_NSIXPCSCRIPTABLE
     SharedScriptableHelperForJSIID() {}
 };
 NS_INTERFACE_MAP_BEGIN(SharedScriptableHelperForJSIID)
   NS_INTERFACE_MAP_ENTRY(nsIXPCScriptable)
   NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIXPCScriptable)
 NS_INTERFACE_MAP_END
 NS_IMPL_ADDREF(SharedScriptableHelperForJSIID)
 NS_IMPL_RELEASE(SharedScriptableHelperForJSIID)
 // The nsIXPCScriptable map declaration that will generate stubs for us...
 #define XPC_MAP_CLASSNAME           SharedScriptableHelperForJSIID
 #define XPC_MAP_QUOTED_CLASSNAME   "JSIID"
 #define XPC_MAP_FLAGS               nsIXPCScriptable::DONT_ENUM_STATIC_PROPS |\
                                     nsIXPCScriptable::ALLOW_PROP_MODS_DURING_RESOLVE
 #include "xpc_map_end.h" /* This will #undef the above */
 static mozilla::StaticRefPtr<nsIXPCScriptable> gSharedScriptableHelperForJSIID;
 static bool gClassObjectsWereInited = false;
 static void EnsureClassObjectsInitialized()
 {
     if (!gClassObjectsWereInited) {
         gSharedScriptableHelperForJSIID = new SharedScriptableHelperForJSIID();
         gClassObjectsWereInited = true;
     }
 }
 NS_METHOD GetSharedScriptableHelperForJSIID(uint32_t language,
                                             nsISupports **helper)
 {
     EnsureClassObjectsInitialized();
     if (language == nsIProgrammingLanguage::JAVASCRIPT) {
         nsCOMPtr<nsIXPCScriptable> temp = gSharedScriptableHelperForJSIID.get();
         temp.forget(helper);
     } else
         *helper = nullptr;
     return NS_OK;
 }
 /******************************************************/
 #define NULL_CID                                                              \
 { 0x00000000, 0x0000, 0x0000,                                                 \
   { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 } }
 // We pass nsIClassInfo::DOM_OBJECT so that nsJSIID instances may be created
 // in unprivileged scopes.
 NS_DECL_CI_INTERFACE_GETTER(nsJSIID)
 NS_IMPL_CLASSINFO(nsJSIID, GetSharedScriptableHelperForJSIID,
                   nsIClassInfo::DOM_OBJECT, NULL_CID)
 NS_DECL_CI_INTERFACE_GETTER(nsJSCID)
 NS_IMPL_CLASSINFO(nsJSCID, nullptr, 0, NULL_CID)
 void xpc_DestroyJSxIDClassObjects()
 {
     if (gClassObjectsWereInited) {
         NS_IF_RELEASE(NS_CLASSINFO_NAME(nsJSIID));
         NS_IF_RELEASE(NS_CLASSINFO_NAME(nsJSCID));
         gSharedScriptableHelperForJSIID = nullptr;
         gClassObjectsWereInited = false;
     }
 }
 /***************************************************************************/
 NS_INTERFACE_MAP_BEGIN(nsJSIID)
   NS_INTERFACE_MAP_ENTRY(nsIJSID)
   NS_INTERFACE_MAP_ENTRY(nsIJSIID)
   NS_INTERFACE_MAP_ENTRY(nsIXPCScriptable)
   NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIJSID)
   NS_IMPL_QUERY_CLASSINFO(nsJSIID)
 NS_INTERFACE_MAP_END
 NS_IMPL_ADDREF(nsJSIID)
 NS_IMPL_RELEASE(nsJSIID)
 NS_IMPL_CI_INTERFACE_GETTER(nsJSIID, nsIJSID, nsIJSIID)
 // The nsIXPCScriptable map declaration that will generate stubs for us...
 #define XPC_MAP_CLASSNAME           nsJSIID
 #define XPC_MAP_QUOTED_CLASSNAME   "nsJSIID"
 #define                             XPC_MAP_WANT_NEWRESOLVE
 #define                             XPC_MAP_WANT_ENUMERATE
 #define                             XPC_MAP_WANT_HASINSTANCE
 #define XPC_MAP_FLAGS               nsIXPCScriptable::DONT_ENUM_STATIC_PROPS |\
                                     nsIXPCScriptable::ALLOW_PROP_MODS_DURING_RESOLVE
 #include "xpc_map_end.h" /* This will #undef the above */
 nsJSIID::nsJSIID(nsIInterfaceInfo* aInfo)
     : mInfo(aInfo)
 {
 }
 nsJSIID::~nsJSIID() {}
 // If mInfo is present we use it and ignore mDetails, else we use mDetails.
 NS_IMETHODIMP nsJSIID::GetName(char * *aName)
 {
     return mInfo->GetName(aName);
 }
 NS_IMETHODIMP nsJSIID::GetNumber(char * *aNumber)
 {
     char str[NSID_LENGTH];
     const nsIID* id;
     mInfo->GetIIDShared(&id);
     id->ToProvidedString(str);
     *aNumber = (char*) nsMemory::Clone(str, NSID_LENGTH);
     return *aNumber ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
 }
 NS_IMETHODIMP_(const nsID*) nsJSIID::GetID()
 {
     const nsIID* id;
     mInfo->GetIIDShared(&id);
     return id;
 }
 NS_IMETHODIMP nsJSIID::GetValid(bool *aValid)
 {
     *aValid = true;
     return NS_OK;
 }
 NS_IMETHODIMP nsJSIID::Equals(nsIJSID *other, bool *_retval)
 {
     if (!_retval)
         return NS_ERROR_NULL_POINTER;
     if (!other) {
         *_retval = false;
         return NS_OK;
     }
     mInfo->IsIID(other->GetID(), _retval);
     return NS_OK;
 }
 NS_IMETHODIMP nsJSIID::Initialize(const char *idString)
 {
     return NS_ERROR_FAILURE;
 }
 NS_IMETHODIMP nsJSIID::ToString(char **_retval)
 {
     return mInfo->GetName(_retval);
 }
 // static
 already_AddRefed<nsJSIID>
 nsJSIID::NewID(nsIInterfaceInfo* aInfo)
 {
     if (!aInfo) {
         NS_ERROR("no info");
         return nullptr;
     }
     bool canScript;
     if (NS_FAILED(aInfo->IsScriptable(&canScript)) || !canScript)
         return nullptr;
     nsRefPtr<nsJSIID> idObj = new nsJSIID(aInfo);
     return idObj.forget();
 }
 /* bool resolve (in nsIXPConnectWrappedNative wrapper, in JSContextPtr cx, in JSObjectPtr obj, in jsval id); */
 NS_IMETHODIMP
 nsJSIID::NewResolve(nsIXPConnectWrappedNative *wrapper,
                     JSContext * cx, JSObject * objArg,
                     jsid idArg, JSObject * *objp,
                     bool *_retval)
 {
     RootedObject obj(cx, objArg);
     RootedId id(cx, idArg);
     XPCCallContext ccx(JS_CALLER, cx);
     AutoMarkingNativeInterfacePtr iface(ccx);
     const nsIID* iid;
     mInfo->GetIIDShared(&iid);
     iface = XPCNativeInterface::GetNewOrUsed(iid);
     if (!iface)
         return NS_OK;
     XPCNativeMember* member = iface->FindMember(id);
     if (member && member->IsConstant()) {
         RootedValue val(cx);
         if (!member->GetConstantValue(ccx, iface, val.address()))
             return NS_ERROR_OUT_OF_MEMORY;
         *objp = obj;
         *_retval = JS_DefinePropertyById(cx, obj, id, val, nullptr, nullptr,
                                          JSPROP_ENUMERATE | JSPROP_READONLY |
                                          JSPROP_PERMANENT);
     }
     return NS_OK;
 }
 /* bool enumerate (in nsIXPConnectWrappedNative wrapper, in JSContextPtr cx, in JSObjectPtr obj); */
 NS_IMETHODIMP
 nsJSIID::Enumerate(nsIXPConnectWrappedNative *wrapper,
                    JSContext * cx, JSObject * objArg, bool *_retval)
 {
     // In this case, let's just eagerly resolve...
     RootedObject obj(cx, objArg);
     XPCCallContext ccx(JS_CALLER, cx);
     AutoMarkingNativeInterfacePtr iface(ccx);
     const nsIID* iid;
     mInfo->GetIIDShared(&iid);
     iface = XPCNativeInterface::GetNewOrUsed(iid);
     if (!iface)
         return NS_OK;
     uint16_t count = iface->GetMemberCount();
     for (uint16_t i = 0; i < count; i++) {
         XPCNativeMember* member = iface->GetMemberAt(i);
         if (member && member->IsConstant() &&
             !xpc_ForcePropertyResolve(cx, obj, member->GetName())) {
             return NS_ERROR_UNEXPECTED;
         }
     }
     return NS_OK;
 }
 /*
  * HasInstance hooks need to find an appropriate reflector in order to function
  * properly. There are two complexities that we need to handle:
  *
  * 1 - Cross-compartment wrappers. Chrome uses over 100 compartments, all with
  *     system principal. The success of an instanceof check should not depend
  *     on which compartment an object comes from. At the same time, we want to
  *     make sure we don't unwrap important security wrappers.
  *     CheckedUnwrap does the right thing here.
  *
  * 2 - Prototype chains. Suppose someone creates a vanilla JS object |a| and
  *     sets its __proto__ to some WN |b|. If |b instanceof nsIFoo| returns true,
  *     one would expect |a instanceof nsIFoo| to return true as well, since
  *     instanceof is transitive up the prototype chain in ECMAScript. Moreover,
  *     there's chrome code that relies on this.
  *
  * This static method handles both complexities, returning either an XPCWN, a
  * DOM object, or null. The object may well be cross-compartment from |cx|.
  */
 static JSObject *
 FindObjectForHasInstance(JSContext *cx, HandleObject objArg)
 {
     RootedObject obj(cx, objArg), proto(cx);
     while (obj && !IS_WN_REFLECTOR(obj) &&
            !IsDOMObject(obj) && !mozilla::jsipc::JavaScriptParent::IsCPOW(obj))
     {
         if (js::IsWrapper(obj)) {
             obj = js::CheckedUnwrap(obj, /* stopAtOuter = */ false);
             continue;
         }
         if (!js::GetObjectProto(cx, obj, &proto))
             return nullptr;
         obj = proto;
     }
     return obj;
 }
 nsresult
 xpc::HasInstance(JSContext *cx, HandleObject objArg, const nsID *iid, bool *bp)
 {
     *bp = false;
     RootedObject obj(cx, FindObjectForHasInstance(cx, objArg));
     if (!obj)
         return NS_OK;
     if (IsDOMObject(obj)) {
         // Not all DOM objects implement nsISupports. But if they don't,
         // there's nothing to do in this HasInstance hook.
         nsISupports *identity = UnwrapDOMObjectToISupports(obj);
         if (!identity)
             return NS_OK;;
         nsCOMPtr<nsISupports> supp;
         identity->QueryInterface(*iid, getter_AddRefs(supp));
         *bp = supp;
         return NS_OK;
     }
     if (mozilla::jsipc::JavaScriptParent::IsCPOW(obj))
         return mozilla::jsipc::JavaScriptParent::InstanceOf(obj, iid, bp);
     MOZ_ASSERT(IS_WN_REFLECTOR(obj));
     XPCWrappedNative* other_wrapper = XPCWrappedNative::Get(obj);
     if (!other_wrapper)
         return NS_OK;
     // We'll trust the interface set of the wrapper if this is known
     // to be an interface that the objects *expects* to be able to
     // handle.
     if (other_wrapper->HasInterfaceNoQI(*iid)) {
         *bp = true;
         return NS_OK;
     }
     // Otherwise, we'll end up Querying the native object to be sure.
     XPCCallContext ccx(JS_CALLER, cx);
     AutoMarkingNativeInterfacePtr iface(ccx);
     iface = XPCNativeInterface::GetNewOrUsed(iid);
     nsresult findResult = NS_OK;
     if (iface && other_wrapper->FindTearOff(iface, false, &findResult))
         *bp = true;
     if (NS_FAILED(findResult) && findResult != NS_ERROR_NO_INTERFACE)
         return findResult;
     return NS_OK;
 }
 /* bool hasInstance (in nsIXPConnectWrappedNative wrapper, in JSContextPtr cx, in JSObjectPtr obj, in jsval val, out bool bp); */
 NS_IMETHODIMP
 nsJSIID::HasInstance(nsIXPConnectWrappedNative *wrapper,
                      JSContext *cx, JSObject * /* unused */,
                      HandleValue val, bool *bp, bool *_retval)
 {
     *bp = false;
     if (val.isPrimitive())
         return NS_OK;
     // we have a JSObject
     RootedObject obj(cx, &val.toObject());
     const nsIID* iid;
     mInfo->GetIIDShared(&iid);
     return xpc::HasInstance(cx, obj, iid, bp);
 }
 /***************************************************************************/
 NS_INTERFACE_MAP_BEGIN(nsJSCID)
   NS_INTERFACE_MAP_ENTRY(nsIJSID)
   NS_INTERFACE_MAP_ENTRY(nsIJSCID)
   NS_INTERFACE_MAP_ENTRY(nsIXPCScriptable)
   NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIJSID)
   NS_IMPL_QUERY_CLASSINFO(nsJSCID)
 NS_INTERFACE_MAP_END
 NS_IMPL_ADDREF(nsJSCID)
 NS_IMPL_RELEASE(nsJSCID)
 NS_IMPL_CI_INTERFACE_GETTER(nsJSCID, nsIJSID, nsIJSCID)
 // The nsIXPCScriptable map declaration that will generate stubs for us...
 #define XPC_MAP_CLASSNAME           nsJSCID
 #define XPC_MAP_QUOTED_CLASSNAME   "nsJSCID"
 #define                             XPC_MAP_WANT_CONSTRUCT
 #define                             XPC_MAP_WANT_HASINSTANCE
 #define XPC_MAP_FLAGS               0
 #include "xpc_map_end.h" /* This will #undef the above */
 nsJSCID::nsJSCID()  {}
 nsJSCID::~nsJSCID() {}
 NS_IMETHODIMP nsJSCID::GetName(char * *aName)
     {ResolveName(); return mDetails.GetName(aName);}
 NS_IMETHODIMP nsJSCID::GetNumber(char * *aNumber)
     {return mDetails.GetNumber(aNumber);}
 NS_IMETHODIMP_(const nsID*) nsJSCID::GetID()
     {return &mDetails.ID();}
 NS_IMETHODIMP nsJSCID::GetValid(bool *aValid)
     {return mDetails.GetValid(aValid);}
 NS_IMETHODIMP nsJSCID::Equals(nsIJSID *other, bool *_retval)
     {return mDetails.Equals(other, _retval);}
 NS_IMETHODIMP nsJSCID::Initialize(const char *idString)
     {return mDetails.Initialize(idString);}
 NS_IMETHODIMP nsJSCID::ToString(char **_retval)
     {ResolveName(); return mDetails.ToString(_retval);}
 void
 nsJSCID::ResolveName()
 {
     if (!mDetails.NameIsSet())
         mDetails.SetNameToNoString();
 }
 //static
 already_AddRefed<nsJSCID>
 nsJSCID::NewID(const char* str)
 {
     if (!str) {
         NS_ERROR("no string");
         return nullptr;
     }
     nsRefPtr<nsJSCID> idObj = new nsJSCID();
     if (str[0] == '{') {
         NS_ENSURE_SUCCESS(idObj->Initialize(str), nullptr);
     } else {
         nsCOMPtr<nsIComponentRegistrar> registrar;
         NS_GetComponentRegistrar(getter_AddRefs(registrar));
         NS_ENSURE_TRUE(registrar, nullptr);
         nsCID *cid;
         if (NS_FAILED(registrar->ContractIDToCID(str, &cid)))
             return nullptr;
         bool success = idObj->mDetails.InitWithName(*cid, str);
         nsMemory::Free(cid);
         if (!success)
             return nullptr;
     }
     return idObj.forget();
 }
 static const nsID*
 GetIIDArg(uint32_t argc, const JS::Value& val, JSContext* cx)
 {
     const nsID* iid;
     // If an IID was passed in then use it
     if (argc) {
         JSObject* iidobj;
         if (JSVAL_IS_PRIMITIVE(val) ||
             !(iidobj = JSVAL_TO_OBJECT(val)) ||
             !(iid = xpc_JSObjectToID(cx, iidobj))) {
             return nullptr;
         }
     } else
         iid = &NS_GET_IID(nsISupports);
     return iid;
 }
 static void
 GetWrapperObject(MutableHandleObject obj)
 {
     obj.set(nullptr);
     nsXPConnect* xpc = nsXPConnect::XPConnect();
     nsAXPCNativeCallContext *ccxp = nullptr;
     xpc->GetCurrentNativeCallContext(&ccxp);
     if (!ccxp)
         return;
     nsCOMPtr<nsIXPConnectWrappedNative> wrapper;
     ccxp->GetCalleeWrapper(getter_AddRefs(wrapper));
     obj.set(wrapper->GetJSObject());
 }
 /* nsISupports createInstance (); */
 NS_IMETHODIMP
 nsJSCID::CreateInstance(HandleValue iidval, JSContext *cx,
                         uint8_t optionalArgc, MutableHandleValue retval)
 {
     if (!mDetails.IsValid())
         return NS_ERROR_XPC_BAD_CID;
     RootedObject obj(cx);
     GetWrapperObject(&obj);
     if (!obj) {
         return NS_ERROR_UNEXPECTED;
     }
     nsIXPCSecurityManager* sm = nsXPConnect::XPConnect()->GetDefaultSecurityManager();
     if (sm && NS_FAILED(sm->CanCreateInstance(cx, mDetails.ID()))) {
         NS_ERROR("how are we not being called from chrome here?");
         return NS_OK;
     }
     // If an IID was passed in then use it
     const nsID* iid = GetIIDArg(optionalArgc, iidval, cx);
     if (!iid)
         return NS_ERROR_XPC_BAD_IID;
     nsCOMPtr<nsIComponentManager> compMgr;
     nsresult rv = NS_GetComponentManager(getter_AddRefs(compMgr));
     if (NS_FAILED(rv))
         return NS_ERROR_UNEXPECTED;
     nsCOMPtr<nsISupports> inst;
     rv = compMgr->CreateInstance(mDetails.ID(), nullptr, *iid, getter_AddRefs(inst));
     MOZ_ASSERT(NS_FAILED(rv) || inst, "component manager returned success, but instance is null!");
     if (NS_FAILED(rv) || !inst)
         return NS_ERROR_XPC_CI_RETURNED_FAILURE;
     rv = nsXPConnect::XPConnect()->WrapNativeToJSVal(cx, obj, inst, nullptr, iid, true, retval);
     if (NS_FAILED(rv) || retval.isPrimitive())
         return NS_ERROR_XPC_CANT_CREATE_WN;
     return NS_OK;
 }
 /* nsISupports getService (); */
 NS_IMETHODIMP
 nsJSCID::GetService(HandleValue iidval, JSContext *cx, uint8_t optionalArgc,
                     MutableHandleValue retval)
 {
     if (!mDetails.IsValid())
         return NS_ERROR_XPC_BAD_CID;
     RootedObject obj(cx);
     GetWrapperObject(&obj);
     if (!obj) {
         return NS_ERROR_UNEXPECTED;
     }
     nsIXPCSecurityManager *sm;
     sm = nsXPConnect::XPConnect()->GetDefaultSecurityManager();
     if (sm && NS_FAILED(sm->CanCreateInstance(cx, mDetails.ID()))) {
         MOZ_ASSERT(JS_IsExceptionPending(cx),
                    "security manager vetoed GetService without setting exception");
         return NS_OK;
     }
     // If an IID was passed in then use it
     const nsID *iid = GetIIDArg(optionalArgc, iidval, cx);
     if (!iid)
         return NS_ERROR_XPC_BAD_IID;
     nsCOMPtr<nsIServiceManager> svcMgr;
     nsresult rv = NS_GetServiceManager(getter_AddRefs(svcMgr));
     if (NS_FAILED(rv))
         return rv;
     nsCOMPtr<nsISupports> srvc;
     rv = svcMgr->GetService(mDetails.ID(), *iid, getter_AddRefs(srvc));
     MOZ_ASSERT(NS_FAILED(rv) || srvc, "service manager returned success, but service is null!");
     if (NS_FAILED(rv) || !srvc)
         return NS_ERROR_XPC_GS_RETURNED_FAILURE;
     nsCOMPtr<nsIXPConnectJSObjectHolder> holder;
     rv = nsXPConnect::XPConnect()->WrapNative(cx, obj, srvc, *iid, getter_AddRefs(holder));
     if (NS_FAILED(rv) || !holder || !holder->GetJSObject())
         return NS_ERROR_XPC_CANT_CREATE_WN;
     retval.setObject(*holder->GetJSObject());
     return NS_OK;
 }
 /* bool construct (in nsIXPConnectWrappedNative wrapper, in JSContextPtr cx, in JSObjectPtr obj, in uint32_t argc, in JSValPtr argv, in JSValPtr vp); */
 NS_IMETHODIMP
 nsJSCID::Construct(nsIXPConnectWrappedNative *wrapper,
                    JSContext *cx, JSObject *objArg,
                    const CallArgs &args, bool *_retval)
 {
     RootedObject obj(cx, objArg);
     XPCJSRuntime* rt = nsXPConnect::GetRuntimeInstance();
     if (!rt)
         return NS_ERROR_FAILURE;
     // 'push' a call context and call on it
     RootedId name(cx, rt->GetStringID(XPCJSRuntime::IDX_CREATE_INSTANCE));
     XPCCallContext ccx(JS_CALLER, cx, obj, JS::NullPtr(), name, args.length(), args.array(),
                        args.rval().address());
     *_retval = XPCWrappedNative::CallMethod(ccx);
     return NS_OK;
 }
 /* bool hasInstance (in nsIXPConnectWrappedNative wrapper, in JSContextPtr cx, in JSObjectPtr obj, in jsval val, out bool bp); */
 NS_IMETHODIMP
 nsJSCID::HasInstance(nsIXPConnectWrappedNative *wrapper,
                      JSContext *cx, JSObject * /* unused */,
                      HandleValue val, bool *bp, bool *_retval)
 {
     *bp = false;
     nsresult rv = NS_OK;
     if (val.isObject()) {
         // we have a JSObject
         RootedObject obj(cx, &val.toObject());
         MOZ_ASSERT(obj, "when is an object not an object?");
         // is this really a native xpcom object with a wrapper?
         nsIClassInfo *ci = nullptr;
         obj = FindObjectForHasInstance(cx, obj);
         if (!obj || !IS_WN_REFLECTOR(obj))
             return rv;
         if (XPCWrappedNative *other_wrapper = XPCWrappedNative::Get(obj))
             ci = other_wrapper->GetClassInfo();
         // We consider CID equality to be the thing that matters here.
         // This is perhaps debatable.
         if (ci) {
             nsID cid;
             if (NS_SUCCEEDED(ci->GetClassIDNoAlloc(&cid)))
                 *bp = cid.Equals(mDetails.ID());
         }
     }
     return rv;
 }
 /***************************************************************************/
 // additional utilities...
 JSObject *
 xpc_NewIDObject(JSContext *cx, HandleObject jsobj, const nsID& aID)
 {
     RootedObject obj(cx);
     nsCOMPtr<nsIJSID> iid = nsJSID::NewID(aID);
     if (iid) {
         nsXPConnect *xpc = nsXPConnect::XPConnect();
         if (xpc) {
             nsCOMPtr<nsIXPConnectJSObjectHolder> holder;
             nsresult rv = xpc->WrapNative(cx, jsobj,
                                           static_cast<nsISupports*>(iid),
                                           NS_GET_IID(nsIJSID),
                                           getter_AddRefs(holder));
             if (NS_SUCCEEDED(rv) && holder) {
                 obj = holder->GetJSObject();
             }
         }
     }
     return obj;
 }
 // note: returned pointer is only valid while |obj| remains alive!
 const nsID*
 xpc_JSObjectToID(JSContext *cx, JSObject *obj)
 {
     if (!cx || !obj)
         return nullptr;
     // NOTE: this call does NOT addref
     XPCWrappedNative *wrapper = nullptr;
     obj = js::CheckedUnwrap(obj);
     if (obj && IS_WN_REFLECTOR(obj))
         wrapper = XPCWrappedNative::Get(obj);
     if (wrapper &&
         (wrapper->HasInterfaceNoQI(NS_GET_IID(nsIJSID))  ||
          wrapper->HasInterfaceNoQI(NS_GET_IID(nsIJSIID)) ||
          wrapper->HasInterfaceNoQI(NS_GET_IID(nsIJSCID)))) {
         return ((nsIJSID*)wrapper->GetIdentityObject())->GetID();
     }
     return nullptr;
 }
 bool
 xpc_JSObjectIsID(JSContext *cx, JSObject *obj)
 {
     MOZ_ASSERT(cx && obj, "bad param");
     // NOTE: this call does NOT addref
     XPCWrappedNative *wrapper = nullptr;
     obj = js::CheckedUnwrap(obj);
     if (obj && IS_WN_REFLECTOR(obj))
         wrapper = XPCWrappedNative::Get(obj);
     return wrapper &&
            (wrapper->HasInterfaceNoQI(NS_GET_IID(nsIJSID))  ||
             wrapper->HasInterfaceNoQI(NS_GET_IID(nsIJSIID)) ||
             wrapper->HasInterfaceNoQI(NS_GET_IID(nsIJSCID)));
 }

The Tor Browser / annotate

js/xpconnect/src/XPCJSID.cpp@129ffea94266 (annotated)

js/xpconnect/src/XPCJSID.cpp