The Tor Browser: js/xpconnect/src/XPCQuickStubs.cpp@6474c204b198 (annotated)

js/xpconnect/src/XPCQuickStubs.cpp@6474c204b198 (annotated)

js/xpconnect/src/XPCQuickStubs.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- 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/. */
 #include "jsapi.h"
 #include "jsfriendapi.h"
 #include "jsprf.h"
 #include "nsCOMPtr.h"
 #include "AccessCheck.h"
 #include "WrapperFactory.h"
 #include "xpcprivate.h"
 #include "XPCInlines.h"
 #include "XPCQuickStubs.h"
 #include "mozilla/dom/BindingUtils.h"
 #include "mozilla/dom/Exceptions.h"
 using namespace mozilla;
 using namespace JS;
 extern const char* xpc_qsStringTable;
 static const xpc_qsHashEntry *
 LookupEntry(uint32_t tableSize, const xpc_qsHashEntry *table, const nsID &iid)
 {
     size_t i;
     const xpc_qsHashEntry *p;
     i = iid.m0 % tableSize;
     do
     {
         p = table + i;
         if (p->iid.Equals(iid))
             return p;
         i = p->chain;
     } while (i != XPC_QS_NULL_INDEX);
     return nullptr;
 }
 static const xpc_qsHashEntry *
 LookupInterfaceOrAncestor(uint32_t tableSize, const xpc_qsHashEntry *table,
                           const nsID &iid)
 {
     const xpc_qsHashEntry *entry = LookupEntry(tableSize, table, iid);
     if (!entry) {
         /*
          * On a miss, we have to search for every interface the object
          * supports, including ancestors.
          */
         nsCOMPtr<nsIInterfaceInfo> info;
         if (NS_FAILED(nsXPConnect::XPConnect()->GetInfoForIID(&iid, getter_AddRefs(info))))
             return nullptr;
         const nsIID *piid;
         for (;;) {
             nsCOMPtr<nsIInterfaceInfo> parent;
             if (NS_FAILED(info->GetParent(getter_AddRefs(parent))) ||
                 !parent ||
                 NS_FAILED(parent->GetIIDShared(&piid))) {
                 break;
             }
             entry = LookupEntry(tableSize, table, *piid);
             if (entry)
                 break;
             info.swap(parent);
         }
     }
     return entry;
 }
 static MOZ_ALWAYS_INLINE bool
 HasBitInInterfacesBitmap(JSObject *obj, uint32_t interfaceBit)
 {
     MOZ_ASSERT(IS_WN_REFLECTOR(obj), "Not a wrapper?");
     const XPCWrappedNativeJSClass *clasp =
       (const XPCWrappedNativeJSClass*)js::GetObjectClass(obj);
     return (clasp->interfacesBitmap & (1 << interfaceBit)) != 0;
 }
 static void
 PointerFinalize(JSFreeOp *fop, JSObject *obj)
 {
     JSPropertyOp *popp = static_cast<JSPropertyOp *>(JS_GetPrivate(obj));
     delete popp;
 }
 const JSClass
 PointerHolderClass = {
     "Pointer", JSCLASS_HAS_PRIVATE,
     JS_PropertyStub, JS_DeletePropertyStub, JS_PropertyStub, JS_StrictPropertyStub,
     JS_EnumerateStub, JS_ResolveStub, JS_ConvertStub, PointerFinalize
 };
 bool
 xpc_qsDefineQuickStubs(JSContext *cx, JSObject *protoArg, unsigned flags,
                        uint32_t ifacec, const nsIID **interfaces,
                        uint32_t tableSize, const xpc_qsHashEntry *table,
                        const xpc_qsPropertySpec *propspecs,
                        const xpc_qsFunctionSpec *funcspecs,
                        const char *stringTable)
 {
     /*
      * Walk interfaces in reverse order to behave like XPConnect when a
      * feature is defined in more than one of the interfaces.
      *
      * XPCNativeSet::FindMethod returns the first matching feature it finds,
      * searching the interfaces forward.  Here, definitions toward the
      * front of 'interfaces' overwrite those toward the back.
      */
     RootedObject proto(cx, protoArg);
     for (uint32_t i = ifacec; i-- != 0;) {
         const nsID &iid = *interfaces[i];
         const xpc_qsHashEntry *entry =
             LookupInterfaceOrAncestor(tableSize, table, iid);
         if (entry) {
             for (;;) {
                 // Define quick stubs for attributes.
                 const xpc_qsPropertySpec *ps = propspecs + entry->prop_index;
                 const xpc_qsPropertySpec *ps_end = ps + entry->n_props;
                 for ( ; ps < ps_end; ++ps) {
                     if (!JS_DefineProperty(cx, proto,
                                            stringTable + ps->name_index,
                                            JS::UndefinedHandleValue,
                                            flags | JSPROP_SHARED | JSPROP_NATIVE_ACCESSORS,
                                            (JSPropertyOp)ps->getter,
                                            (JSStrictPropertyOp)ps->setter))
                         return false;
                 }
                 // Define quick stubs for methods.
                 const xpc_qsFunctionSpec *fs = funcspecs + entry->func_index;
                 const xpc_qsFunctionSpec *fs_end = fs + entry->n_funcs;
                 for ( ; fs < fs_end; ++fs) {
                     if (!JS_DefineFunction(cx, proto,
                                            stringTable + fs->name_index,
                                            reinterpret_cast<JSNative>(fs->native),
                                            fs->arity, flags))
                         return false;
                 }
                 if (entry->newBindingProperties) {
                     if (entry->newBindingProperties->regular) {
                         mozilla::dom::DefineWebIDLBindingPropertiesOnXPCObject(cx, proto, entry->newBindingProperties->regular, false);
                     }
                     if (entry->newBindingProperties->chromeOnly &&
                         xpc::AccessCheck::isChrome(js::GetContextCompartment(cx))) {
                         mozilla::dom::DefineWebIDLBindingPropertiesOnXPCObject(cx, proto, entry->newBindingProperties->chromeOnly, false);
                     }
                 }
                 // Next.
                 size_t j = entry->parentInterface;
                 if (j == XPC_QS_NULL_INDEX)
                     break;
                 entry = table + j;
             }
         }
     }
     return true;
 }
 bool
 xpc_qsThrow(JSContext *cx, nsresult rv)
 {
     XPCThrower::Throw(rv, cx);
     return false;
 }
 /**
  * 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();
             }
         }
     }
 }
 static void
 GetMethodInfo(JSContext *cx, jsval *vp, const char **ifaceNamep, jsid *memberIdp)
 {
     CallReceiver call = CallReceiverFromVp(vp);
     RootedObject funobj(cx, &call.callee());
     MOZ_ASSERT(JS_ObjectIsFunction(cx, funobj),
                "JSNative callee should be Function object");
     RootedString str(cx, JS_GetFunctionId(JS_GetObjectFunction(funobj)));
     RootedId methodId(cx, str ? INTERNED_STRING_TO_JSID(cx, str) : JSID_VOID);
     GetMemberInfo(&call.thisv().toObject(), methodId, ifaceNamep);
     *memberIdp = methodId;
 }
 static bool
 ThrowCallFailed(JSContext *cx, nsresult rv,
                 const char *ifaceName, HandleId memberId, const char *memberName)
 {
     /* Only one of memberId or memberName should be given. */
     MOZ_ASSERT(JSID_IS_VOID(memberId) != !memberName);
     // From XPCThrower::ThrowBadResult.
     char* sz;
     const char* format;
     const char* name;
     // If the cx already has a pending exception, just throw that.
     //
     // We used to check here to make sure the exception matched rv (whatever
     // that means). But this meant that we'd be calling into JSAPI below with
     // a pending exception, which isn't really kosher. The first exception thrown
     // should generally take precedence anyway.
     if (JS_IsExceptionPending(cx))
         return false;
     // else...
     if (!nsXPCException::NameAndFormatForNSResult(NS_ERROR_XPC_NATIVE_RETURNED_FAILURE, nullptr, &format) ||
         !format) {
         format = "";
     }
     JSAutoByteString memberNameBytes;
     if (!memberName) {
         memberName = JSID_IS_STRING(memberId)
                      ? memberNameBytes.encodeLatin1(cx, JSID_TO_STRING(memberId))
                      : "unknown";
     }
     if (nsXPCException::NameAndFormatForNSResult(rv, &name, nullptr)
         && name) {
         sz = JS_smprintf("%s 0x%x (%s) [%s.%s]",
                          format, rv, name, ifaceName, memberName);
     } else {
         sz = JS_smprintf("%s 0x%x [%s.%s]",
                          format, rv, ifaceName, memberName);
     }
     dom::Throw(cx, rv, sz);
     if (sz)
         JS_smprintf_free(sz);
     return false;
 }
 bool
 xpc_qsThrowGetterSetterFailed(JSContext *cx, nsresult rv, JSObject *obj,
                               jsid memberIdArg)
 {
     RootedId memberId(cx, memberIdArg);
     const char *ifaceName;
     GetMemberInfo(obj, memberId, &ifaceName);
     return ThrowCallFailed(cx, rv, ifaceName, memberId, nullptr);
 }
 bool
 xpc_qsThrowGetterSetterFailed(JSContext *cx, nsresult rv, JSObject *objArg,
                               const char* memberName)
 {
     RootedObject obj(cx, objArg);
     JSString *str = JS_InternString(cx, memberName);
     if (!str) {
         return false;
     }
     return xpc_qsThrowGetterSetterFailed(cx, rv, obj,
                                          INTERNED_STRING_TO_JSID(cx, str));
 }
 bool
 xpc_qsThrowGetterSetterFailed(JSContext *cx, nsresult rv, JSObject *obj,
                               uint16_t memberIndex)
 {
     return xpc_qsThrowGetterSetterFailed(cx, rv, obj,
                                          xpc_qsStringTable + memberIndex);
 }
 bool
 xpc_qsThrowMethodFailed(JSContext *cx, nsresult rv, jsval *vp)
 {
     const char *ifaceName;
     RootedId memberId(cx);
     GetMethodInfo(cx, vp, &ifaceName, memberId.address());
     return ThrowCallFailed(cx, rv, ifaceName, memberId, nullptr);
 }
 static void
 ThrowBadArg(JSContext *cx, nsresult rv, const char *ifaceName,
             jsid memberId, const char *memberName, unsigned paramnum)
 {
     /* Only one memberId or memberName should be given. */
     MOZ_ASSERT(JSID_IS_VOID(memberId) != !memberName);
     // From XPCThrower::ThrowBadParam.
     char* sz;
     const char* format;
     if (!nsXPCException::NameAndFormatForNSResult(rv, nullptr, &format))
         format = "";
     JSAutoByteString memberNameBytes;
     if (!memberName) {
         memberName = JSID_IS_STRING(memberId)
                      ? memberNameBytes.encodeLatin1(cx, JSID_TO_STRING(memberId))
                      : "unknown";
     }
     sz = JS_smprintf("%s arg %u [%s.%s]",
                      format, (unsigned int) paramnum, ifaceName, memberName);
     dom::Throw(cx, rv, sz);
     if (sz)
         JS_smprintf_free(sz);
 }
 void
 xpc_qsThrowBadArg(JSContext *cx, nsresult rv, jsval *vp, unsigned paramnum)
 {
     const char *ifaceName;
     RootedId memberId(cx);
     GetMethodInfo(cx, vp, &ifaceName, memberId.address());
     ThrowBadArg(cx, rv, ifaceName, memberId, nullptr, paramnum);
 }
 void
 xpc_qsThrowBadArgWithCcx(XPCCallContext &ccx, nsresult rv, unsigned paramnum)
 {
     XPCThrower::ThrowBadParam(rv, paramnum, ccx);
 }
 void
 xpc_qsThrowBadArgWithDetails(JSContext *cx, nsresult rv, unsigned paramnum,
                              const char *ifaceName, const char *memberName)
 {
     ThrowBadArg(cx, rv, ifaceName, JSID_VOID, memberName, paramnum);
 }
 void
 xpc_qsThrowBadSetterValue(JSContext *cx, nsresult rv,
                           JSObject *obj, jsid propIdArg)
 {
     RootedId propId(cx, propIdArg);
     const char *ifaceName;
     GetMemberInfo(obj, propId, &ifaceName);
     ThrowBadArg(cx, rv, ifaceName, propId, nullptr, 0);
 }
 void
 xpc_qsThrowBadSetterValue(JSContext *cx, nsresult rv,
                           JSObject *objArg, const char* propName)
 {
     RootedObject obj(cx, objArg);
     JSString *str = JS_InternString(cx, propName);
     if (!str) {
         return;
     }
     xpc_qsThrowBadSetterValue(cx, rv, obj, INTERNED_STRING_TO_JSID(cx, str));
 }
 void
 xpc_qsThrowBadSetterValue(JSContext *cx, nsresult rv, JSObject *obj,
                           uint16_t name_index)
 {
     xpc_qsThrowBadSetterValue(cx, rv, obj, xpc_qsStringTable + name_index);
 }
 bool
 xpc_qsGetterOnlyPropertyStub(JSContext *cx, HandleObject obj, HandleId id, bool strict,
                              MutableHandleValue vp)
 {
     return JS_ReportErrorFlagsAndNumber(cx,
                                         JSREPORT_WARNING | JSREPORT_STRICT |
                                         JSREPORT_STRICT_MODE_ERROR,
                                         js_GetErrorMessage, nullptr,
                                         JSMSG_GETTER_ONLY);
 }
 bool
 xpc_qsGetterOnlyNativeStub(JSContext *cx, unsigned argc, jsval *vp)
 {
     return JS_ReportErrorFlagsAndNumber(cx,
                                         JSREPORT_WARNING | JSREPORT_STRICT |
                                         JSREPORT_STRICT_MODE_ERROR,
                                         js_GetErrorMessage, nullptr,
                                         JSMSG_GETTER_ONLY);
 }
 xpc_qsDOMString::xpc_qsDOMString(JSContext *cx, HandleValue v,
                                  MutableHandleValue pval, bool notpassed,
                                  StringificationBehavior nullBehavior,
                                  StringificationBehavior undefinedBehavior)
 {
     typedef implementation_type::char_traits traits;
     // From the T_DOMSTRING case in XPCConvert::JSData2Native.
     JSString *s = InitOrStringify<traits>(cx, v,
                                           pval, notpassed,
                                           nullBehavior,
                                           undefinedBehavior);
     if (!s)
         return;
     size_t len;
     const jschar *chars = JS_GetStringCharsZAndLength(cx, s, &len);
     if (!chars) {
         mValid = false;
         return;
     }
     new(mBuf) implementation_type(chars, len);
     mValid = true;
 }
 xpc_qsACString::xpc_qsACString(JSContext *cx, HandleValue v,
                                MutableHandleValue pval, bool notpassed,
                                StringificationBehavior nullBehavior,
                                StringificationBehavior undefinedBehavior)
 {
     typedef implementation_type::char_traits traits;
     // From the T_CSTRING case in XPCConvert::JSData2Native.
     JSString *s = InitOrStringify<traits>(cx, v,
                                           pval, notpassed,
                                           nullBehavior,
                                           undefinedBehavior);
     if (!s)
         return;
     size_t len = JS_GetStringEncodingLength(cx, s);
     if (len == size_t(-1)) {
         mValid = false;
         return;
     }
     JSAutoByteString bytes(cx, s);
     if (!bytes) {
         mValid = false;
         return;
     }
     new(mBuf) implementation_type(bytes.ptr(), len);
     mValid = true;
 }
 xpc_qsAUTF8String::xpc_qsAUTF8String(JSContext *cx, HandleValue v, MutableHandleValue pval, bool notpassed)
 {
     typedef nsCharTraits<char16_t> traits;
     // From the T_UTF8STRING  case in XPCConvert::JSData2Native.
     JSString *s = InitOrStringify<traits>(cx, v, pval, notpassed, eNull, eNull);
     if (!s)
         return;
     size_t len;
     const char16_t *chars = JS_GetStringCharsZAndLength(cx, s, &len);
     if (!chars) {
         mValid = false;
         return;
     }
     new(mBuf) implementation_type(chars, len);
     mValid = true;
 }
 static nsresult
 getNative(nsISupports *idobj,
           HandleObject obj,
           const nsIID &iid,
           void **ppThis,
           nsISupports **pThisRef,
           jsval *vp)
 {
     nsresult rv = idobj->QueryInterface(iid, ppThis);
     *pThisRef = static_cast<nsISupports*>(*ppThis);
     if (NS_SUCCEEDED(rv))
         *vp = OBJECT_TO_JSVAL(obj);
     return rv;
 }
 static inline nsresult
 getNativeFromWrapper(JSContext *cx,
                      XPCWrappedNative *wrapper,
                      const nsIID &iid,
                      void **ppThis,
                      nsISupports **pThisRef,
                      jsval *vp)
 {
     RootedObject obj(cx, wrapper->GetFlatJSObject());
     return getNative(wrapper->GetIdentityObject(), obj, iid, ppThis, pThisRef,
                      vp);
 }
 nsresult
 getWrapper(JSContext *cx,
            JSObject *obj,
            XPCWrappedNative **wrapper,
            JSObject **cur,
            XPCWrappedNativeTearOff **tearoff)
 {
     // We can have at most three layers in need of unwrapping here:
     // * A (possible) security wrapper
     // * A (possible) Xray waiver
     // * A (possible) outer window
     //
     // If we pass stopAtOuter == false, we can handle all three with one call
     // to js::CheckedUnwrap.
     if (js::IsWrapper(obj)) {
         JSObject* inner = js::CheckedUnwrap(obj, /* stopAtOuter = */ false);
         // Hack - For historical reasons, wrapped chrome JS objects have been
         // passable as native interfaces. We'd like to fix this, but it
         // involves fixing the contacts API and PeerConnection to stop using
         // COWs. This needs to happen, but for now just preserve the old
         // behavior.
         //
         // Note that there is an identical hack in
         // XPCConvert::JSObject2NativeInterface which should be removed if this
         // one is.
         if (!inner && MOZ_UNLIKELY(xpc::WrapperFactory::IsCOW(obj)))
             inner = js::UncheckedUnwrap(obj);
         // The safe unwrap might have failed if we encountered an object that
         // we're not allowed to unwrap. If it didn't fail though, we should be
         // done with wrappers.
         if (!inner)
             return NS_ERROR_XPC_SECURITY_MANAGER_VETO;
         MOZ_ASSERT(!js::IsWrapper(inner));
         obj = inner;
     }
     // Start with sane values.
     *wrapper = nullptr;
     *cur = nullptr;
     *tearoff = nullptr;
     if (dom::IsDOMObject(obj)) {
         *cur = obj;
         return NS_OK;
     }
     // Handle tearoffs.
     //
     // If |obj| is of the tearoff class, that means we're dealing with a JS
     // object reflection of a particular interface (ie, |foo.nsIBar|). These
     // JS objects are parented to their wrapper, so we snag the tearoff object
     // along the way (if desired), and then set |obj| to its parent.
     const js::Class* clasp = js::GetObjectClass(obj);
     if (clasp == &XPC_WN_Tearoff_JSClass) {
         *tearoff = (XPCWrappedNativeTearOff*) js::GetObjectPrivate(obj);
         obj = js::GetObjectParent(obj);
     }
     // If we've got a WN, store things the way callers expect. Otherwise, leave
     // things null and return.
     if (IS_WN_CLASS(clasp))
         *wrapper = XPCWrappedNative::Get(obj);
     return NS_OK;
 }
 nsresult
 castNative(JSContext *cx,
            XPCWrappedNative *wrapper,
            JSObject *curArg,
            XPCWrappedNativeTearOff *tearoff,
            const nsIID &iid,
            void **ppThis,
            nsISupports **pThisRef,
            MutableHandleValue vp)
 {
     RootedObject cur(cx, curArg);
     if (wrapper) {
         nsresult rv = getNativeFromWrapper(cx,wrapper, iid, ppThis, pThisRef,
                                            vp.address());
         if (rv != NS_ERROR_NO_INTERFACE)
             return rv;
     } else if (cur) {
         nsISupports *native;
         if (!(native = mozilla::dom::UnwrapDOMObjectToISupports(cur))) {
             *pThisRef = nullptr;
             return NS_ERROR_ILLEGAL_VALUE;
         }
         if (NS_SUCCEEDED(getNative(native, cur, iid, ppThis, pThisRef, vp.address()))) {
             return NS_OK;
         }
     }
     *pThisRef = nullptr;
     return NS_ERROR_XPC_BAD_OP_ON_WN_PROTO;
 }
 nsISupports*
 castNativeFromWrapper(JSContext *cx,
                       JSObject *obj,
                       uint32_t interfaceBit,
                       uint32_t protoID,
                       int32_t protoDepth,
                       nsISupports **pRef,
                       MutableHandleValue pVal,
                       nsresult *rv)
 {
     XPCWrappedNative *wrapper;
     XPCWrappedNativeTearOff *tearoff;
     JSObject *cur;
     if (IS_WN_REFLECTOR(obj)) {
         cur = obj;
         wrapper = XPCWrappedNative::Get(obj);
         tearoff = nullptr;
     } else {
         *rv = getWrapper(cx, obj, &wrapper, &cur, &tearoff);
         if (NS_FAILED(*rv))
             return nullptr;
     }
     nsISupports *native;
     if (wrapper) {
         native = wrapper->GetIdentityObject();
         cur = wrapper->GetFlatJSObject();
         if (!native || !HasBitInInterfacesBitmap(cur, interfaceBit)) {
             native = nullptr;
         }
     } else if (cur && protoDepth >= 0) {
         const mozilla::dom::DOMClass* domClass =
             mozilla::dom::GetDOMClass(cur);
         native = mozilla::dom::UnwrapDOMObject<nsISupports>(cur);
         if (native &&
             (uint32_t)domClass->mInterfaceChain[protoDepth] != protoID) {
             native = nullptr;
         }
     } else {
         native = nullptr;
     }
     if (native) {
         *pRef = nullptr;
         pVal.setObjectOrNull(cur);
         *rv = NS_OK;
     } else {
         *rv = NS_ERROR_XPC_BAD_CONVERT_JS;
     }
     return native;
 }
 bool
 xpc_qsUnwrapThisFromCcxImpl(XPCCallContext &ccx,
                             const nsIID &iid,
                             void **ppThis,
                             nsISupports **pThisRef,
                             jsval *vp)
 {
     nsISupports *native = ccx.GetIdentityObject();
     if (!native)
         return xpc_qsThrow(ccx.GetJSContext(), NS_ERROR_XPC_HAS_BEEN_SHUTDOWN);
     RootedObject obj(ccx, ccx.GetFlattenedJSObject());
     nsresult rv = getNative(native, obj, iid, ppThis, pThisRef, vp);
     if (NS_FAILED(rv))
         return xpc_qsThrow(ccx.GetJSContext(), rv);
     return true;
 }
 nsresult
 xpc_qsUnwrapArgImpl(JSContext *cx,
                     HandleValue v,
                     const nsIID &iid,
                     void **ppArg,
                     nsISupports **ppArgRef,
                     MutableHandleValue vp)
 {
     nsresult rv;
     RootedObject src(cx, xpc_qsUnwrapObj(v, ppArgRef, &rv));
     if (!src) {
         *ppArg = nullptr;
         return rv;
     }
     XPCWrappedNative *wrapper;
     XPCWrappedNativeTearOff *tearoff;
     JSObject *obj2;
     rv = getWrapper(cx, src, &wrapper, &obj2, &tearoff);
     NS_ENSURE_SUCCESS(rv, rv);
     if (wrapper || obj2) {
         if (NS_FAILED(castNative(cx, wrapper, obj2, tearoff, iid, ppArg,
                                  ppArgRef, vp)))
             return NS_ERROR_XPC_BAD_CONVERT_JS;
         return NS_OK;
     }
     // else...
     // Slow path.
     // Try to unwrap a slim wrapper.
     nsISupports *iface;
     if (XPCConvert::GetISupportsFromJSObject(src, &iface)) {
         if (!iface || NS_FAILED(iface->QueryInterface(iid, ppArg))) {
             *ppArgRef = nullptr;
             return NS_ERROR_XPC_BAD_CONVERT_JS;
         }
         *ppArgRef = static_cast<nsISupports*>(*ppArg);
         return NS_OK;
     }
     // Create the ccx needed for quick stubs.
     XPCCallContext ccx(JS_CALLER, cx);
     if (!ccx.IsValid()) {
         *ppArgRef = nullptr;
         return NS_ERROR_XPC_BAD_CONVERT_JS;
     }
     nsRefPtr<nsXPCWrappedJS> wrappedJS;
     rv = nsXPCWrappedJS::GetNewOrUsed(src, iid, getter_AddRefs(wrappedJS));
     if (NS_FAILED(rv) || !wrappedJS) {
         *ppArgRef = nullptr;
         return rv;
     }
     // We need to go through the QueryInterface logic to make this return
     // the right thing for the various 'special' interfaces; e.g.
     // nsIPropertyBag. We must use AggregatedQueryInterface in cases where
     // there is an outer to avoid nasty recursion.
     rv = wrappedJS->QueryInterface(iid, ppArg);
     if (NS_SUCCEEDED(rv)) {
         *ppArgRef = static_cast<nsISupports*>(*ppArg);
         vp.setObjectOrNull(wrappedJS->GetJSObject());
     }
     return rv;
 }
 bool
 xpc_qsJsvalToCharStr(JSContext *cx, HandleValue v, JSAutoByteString *bytes)
 {
     MOZ_ASSERT(!bytes->ptr());
     if (v.isNullOrUndefined())
       return true;
     JSString *str = ToString(cx, v);
     if (!str)
       return false;
     return !!bytes->encodeLatin1(cx, str);
 }
 namespace xpc {
 bool
 NonVoidStringToJsval(JSContext *cx, nsAString &str, MutableHandleValue rval)
 {
     nsStringBuffer* sharedBuffer;
     if (!XPCStringConvert::ReadableToJSVal(cx, str, &sharedBuffer, rval))
       return false;
     if (sharedBuffer) {
         // The string was shared but ReadableToJSVal didn't addref it.
         // Move the ownership from str to jsstr.
         str.ForgetSharedBuffer();
     }
     return true;
 }
 } // namespace xpc
 bool
 xpc_qsXPCOMObjectToJsval(JSContext *cx, qsObjectHelper &aHelper,
                          const nsIID *iid, XPCNativeInterface **iface,
                          MutableHandleValue rval)
 {
     NS_PRECONDITION(iface, "Who did that and why?");
     // From the T_INTERFACE case in XPCConvert::NativeData2JS.
     // This is one of the slowest things quick stubs do.
     nsresult rv;
     if (!XPCConvert::NativeInterface2JSObject(rval, nullptr,
                                               aHelper, iid, iface,
                                               true, &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(cx))
             xpc_qsThrow(cx, NS_FAILED(rv) ? rv : NS_ERROR_UNEXPECTED);
         return false;
     }
 #ifdef DEBUG
     JSObject* jsobj = rval.toObjectOrNull();
     if (jsobj && !js::GetObjectParent(jsobj))
         MOZ_ASSERT(js::GetObjectClass(jsobj)->flags & JSCLASS_IS_GLOBAL,
                    "Why did we recreate this wrapper?");
 #endif
     return true;
 }
 bool
 xpc_qsVariantToJsval(JSContext *aCx,
                      nsIVariant *p,
                      MutableHandleValue rval)
 {
     // From the T_INTERFACE case in XPCConvert::NativeData2JS.
     // Error handling is in XPCWrappedNative::CallMethod.
     if (p) {
         nsresult rv;
         bool ok = XPCVariant::VariantDataToJS(p, &rv, rval);
         if (!ok)
             xpc_qsThrow(aCx, rv);
         return ok;
     }
     rval.setNull();
     return true;
 }
 #ifdef DEBUG
 void
 xpc_qsAssertContextOK(JSContext *cx)
 {
     XPCJSContextStack* stack = XPCJSRuntime::Get()->GetJSContextStack();
     JSContext *topJSContext = stack->Peek();
     // This is what we're actually trying to assert here.
     MOZ_ASSERT(cx == topJSContext, "wrong context on XPCJSContextStack!");
 }
 #endif

The Tor Browser / annotate

js/xpconnect/src/XPCQuickStubs.cpp@6474c204b198 (annotated)

js/xpconnect/src/XPCQuickStubs.cpp