Bug 1611173 - Remove support for non-nsISupports XPIDL interfaces. r=nika

It used to be that some XPIDL interfaces were allowed to be non-nsISupports,
and were only used to hold a bunch of constants. It appears that we've now
had enough de-COM work happen that there are no longer any, so we can remove
support for this.

Differential Revision: https://phabricator.services.mozilla.com/D61008

--HG--
extra : moz-landing-system : lando

js/xpconnect/src/XPCWrappedJSClass.cpp

@@ -97,11 +97,7 @@ class MOZ_STACK_CLASS AutoSavePendingResult {
 // static
 const nsXPTInterfaceInfo* nsXPCWrappedJS::GetInterfaceInfo(REFNSIID aIID) {
   const nsXPTInterfaceInfo* info = nsXPTInterfaceInfo::ByIID(aIID);
-  if (!info) {
-    return nullptr;
-  }
-
-  if (info->IsBuiltinClass() || !nsXPConnect::IsISupportsDescendant(info)) {
+  if (!info || info->IsBuiltinClass()) {
     return nullptr;
   }
 

js/xpconnect/src/XPCWrappedNativeInfo.cpp

@@ -248,16 +248,6 @@ already_AddRefed<XPCNativeInterface> XPCNativeInterface::NewInstance(
 
   uint16_t methodCount = aInfo->MethodCount();
   uint16_t constCount = aInfo->ConstantCount();
-
-  // If the interface does not have nsISupports in its inheritance chain
-  // then we know we can't reflect its methods. However, some interfaces that
-  // are used just to reflect constants are declared this way. We need to
-  // go ahead and build the thing. But, we'll ignore whatever methods it may
-  // have.
-  if (!nsXPConnect::IsISupportsDescendant(aInfo)) {
-    methodCount = 0;
-  }
-
   totalCount = methodCount + constCount;
 
   if (totalCount > MAX_LOCAL_MEMBER_COUNT) {

js/xpconnect/src/nsXPConnect.cpp

@@ -166,11 +166,6 @@ XPCJSRuntime* nsXPConnect::GetRuntimeInstance() {
   return gSelf->mRuntime;
 }
 
-// static
-bool nsXPConnect::IsISupportsDescendant(const nsXPTInterfaceInfo* info) {
-  return info && info->HasAncestor(NS_GET_IID(nsISupports));
-}
-
 void xpc::ErrorBase::Init(JSErrorBase* aReport) {
   if (!aReport->filename) {
     mFileName.SetIsVoid(true);

js/xpconnect/src/xpcprivate.h

@@ -226,8 +226,6 @@ class nsXPConnect final : public nsIXPConnect {
   static XPCJSRuntime* GetRuntimeInstance();
   XPCJSContext* GetContext() { return mContext; }
 
-  static bool IsISupportsDescendant(const nsXPTInterfaceInfo* info);
-
   static nsIScriptSecurityManager* SecurityManager() {
     MOZ_ASSERT(NS_IsMainThread());
     MOZ_ASSERT(gScriptSecurityManager);

xpcom/idl-parser/xpidl/rust.py

@@ -479,12 +479,7 @@ def write_interface(iface, fd):
     if iface.namemap is None:
         raise Exception("Interface was not resolved.")
 
-    # if we see a base class-less type other than nsISupports, we just need
-    # to discard anything else about it other than its constants.
-    if iface.base is None and iface.name != "nsISupports":
-        assert len([m for m in iface.members
-                    if type(m) == xpidl.Attribute or type(m) == xpidl.Method]) == 0
-        return
+    assert iface.base or (iface.name == "nsISupports")
 
     # Extract the UUID's information so that it can be written into the struct definition
     names = uuid_decoder.match(iface.attributes.uuid).groupdict()

xpcom/idl-parser/xpidl/rust_macros.py

@@ -51,12 +51,7 @@ def write_interface(iface, fd):
     if iface.namemap is None:
         raise Exception("Interface was not resolved.")
 
-    # if we see a base class-less type other than nsISupports, we just need
-    # to discard anything else about it other than its constants.
-    if iface.base is None and iface.name != "nsISupports":
-        assert len([m for m in iface.members
-                    if type(m) == xpidl.Attribute or type(m) == xpidl.Method]) == 0
-        return
+    assert iface.base or (iface.name == "nsISupports")
 
     base = 'Some("%s")' % iface.base if iface.base is not None else 'None'
     try:

xpcom/idl-parser/xpidl/xpidl.py

@@ -704,6 +704,8 @@ class Interface(object):
                 raise IDLError("interface '%s' is not builtinclass but derives from "
                                "builtinclass '%s'" %
                                (self.name, self.base), self.location)
+        elif self.name != 'nsISupports':
+            raise IDLError("Interface '%s' must inherit from nsISupports" % self.name, self.location)
 
         for member in self.members:
             member.resolve(self)