The Tor Browser: dom/xbl/nsXBLProtoImpl.cpp@6474c204b198 (annotated)

dom/xbl/nsXBLProtoImpl.cpp@6474c204b198 (annotated)

dom/xbl/nsXBLProtoImpl.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: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* 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 "mozilla/DebugOnly.h"
 #include "nsXBLProtoImpl.h"
 #include "nsIContent.h"
 #include "nsIDocument.h"
 #include "nsContentUtils.h"
 #include "nsCxPusher.h"
 #include "nsIScriptGlobalObject.h"
 #include "nsIScriptContext.h"
 #include "nsIXPConnect.h"
 #include "nsIServiceManager.h"
 #include "nsIDOMNode.h"
 #include "nsXBLPrototypeBinding.h"
 #include "nsXBLProtoImplProperty.h"
 #include "nsIURI.h"
 #include "mozilla/dom/XULElementBinding.h"
 #include "xpcpublic.h"
 #include "js/CharacterEncoding.h"
 using namespace mozilla;
 using js::GetGlobalForObjectCrossCompartment;
 using js::AssertSameCompartment;
 nsresult
 nsXBLProtoImpl::InstallImplementation(nsXBLPrototypeBinding* aPrototypeBinding,
                                       nsXBLBinding* aBinding)
 {
   // This function is called to install a concrete implementation on a bound element using
   // this prototype implementation as a guide.  The prototype implementation is compiled lazily,
   // so for the first bound element that needs a concrete implementation, we also build the
   // prototype implementation.
   if (!mMembers && !mFields)  // Constructor and destructor also live in mMembers
     return NS_OK; // Nothing to do, so let's not waste time.
   // If the way this gets the script context changes, fix
   // nsXBLProtoImplAnonymousMethod::Execute
   nsIDocument* document = aBinding->GetBoundElement()->OwnerDoc();
   nsCOMPtr<nsIScriptGlobalObject> global =  do_QueryInterface(document->GetScopeObject());
   if (!global) return NS_OK;
   nsCOMPtr<nsIScriptContext> context = global->GetContext();
   if (!context) return NS_OK;
   JSContext* cx = context->GetNativeContext();
   AutoCxPusher pusher(cx);
   // InitTarget objects gives us back the JS object that represents the bound element and the
   // class object in the bound document that represents the concrete version of this implementation.
   // This function also has the side effect of building up the prototype implementation if it has
   // not been built already.
   JS::Rooted<JSObject*> targetClassObject(cx, nullptr);
   bool targetObjectIsNew = false;
   nsresult rv = InitTargetObjects(aPrototypeBinding,
                                   aBinding->GetBoundElement(),
                                   &targetClassObject,
                                   &targetObjectIsNew);
   NS_ENSURE_SUCCESS(rv, rv); // kick out if we were unable to properly intialize our target objects
   MOZ_ASSERT(targetClassObject);
   // If the prototype already existed, we don't need to install anything. return early.
   if (!targetObjectIsNew)
     return NS_OK;
   // We want to define the canonical set of members in a safe place. If we're
   // using a separate XBL scope, we want to define them there first (so that
   // they'll be available for Xray lookups, among other things), and then copy
   // the properties to the content-side prototype as needed. We don't need to
   // bother about the field accessors here, since we don't use/support those
   // for in-content bindings.
   // First, start by entering the compartment of the XBL scope. This may or may
   // not be the same compartment as globalObject.
   JS::Rooted<JSObject*> globalObject(cx,
     GetGlobalForObjectCrossCompartment(targetClassObject));
   JS::Rooted<JSObject*> scopeObject(cx, xpc::GetXBLScopeOrGlobal(cx, globalObject));
   NS_ENSURE_TRUE(scopeObject, NS_ERROR_OUT_OF_MEMORY);
   JSAutoCompartment ac(cx, scopeObject);
   // If they're different, create our safe holder object in the XBL scope.
   JS::Rooted<JSObject*> propertyHolder(cx);
   if (scopeObject != globalObject) {
     // This is just a property holder, so it doesn't need any special JSClass.
     propertyHolder = JS_NewObjectWithGivenProto(cx, nullptr, JS::NullPtr(), scopeObject);
     NS_ENSURE_TRUE(propertyHolder, NS_ERROR_OUT_OF_MEMORY);
     // Define it as a property on the scopeObject, using the same name used on
     // the content side.
     bool ok = JS_DefineProperty(cx, scopeObject, aPrototypeBinding->ClassName().get(),
                                 propertyHolder, JSPROP_PERMANENT | JSPROP_READONLY,
                                 JS_PropertyStub, JS_StrictPropertyStub);
     NS_ENSURE_TRUE(ok, NS_ERROR_UNEXPECTED);
   } else {
     propertyHolder = targetClassObject;
   }
   // Walk our member list and install each one in turn on the XBL scope object.
   for (nsXBLProtoImplMember* curr = mMembers;
        curr;
        curr = curr->GetNext())
     curr->InstallMember(cx, propertyHolder);
   // Now, if we're using a separate XBL scope, enter the compartment of the
   // bound node and copy exposable properties to the prototype there. This
   // rewraps them appropriately, which should result in cross-compartment
   // function wrappers.
   if (propertyHolder != targetClassObject) {
     AssertSameCompartment(propertyHolder, scopeObject);
     AssertSameCompartment(targetClassObject, globalObject);
     for (nsXBLProtoImplMember* curr = mMembers; curr; curr = curr->GetNext()) {
       if (curr->ShouldExposeToUntrustedContent()) {
         JS::Rooted<jsid> id(cx);
         JS::TwoByteChars chars(curr->GetName(), NS_strlen(curr->GetName()));
         bool ok = JS_CharsToId(cx, chars, &id);
         NS_ENSURE_TRUE(ok, NS_ERROR_UNEXPECTED);
         JS_CopyPropertyFrom(cx, id, targetClassObject, propertyHolder);
         NS_ENSURE_TRUE(ok, NS_ERROR_UNEXPECTED);
       }
     }
   }
   // From here on out, work in the scope of the bound element.
   JSAutoCompartment ac2(cx, targetClassObject);
   // Install all of our field accessors.
   for (nsXBLProtoImplField* curr = mFields;
        curr;
        curr = curr->GetNext())
     curr->InstallAccessors(cx, targetClassObject);
   return NS_OK;
 }
 nsresult
 nsXBLProtoImpl::InitTargetObjects(nsXBLPrototypeBinding* aBinding,
                                   nsIContent* aBoundElement,
                                   JS::MutableHandle<JSObject*> aTargetClassObject,
                                   bool* aTargetIsNew)
 {
   nsresult rv = NS_OK;
   if (!mPrecompiledMemberHolder) {
     rv = CompilePrototypeMembers(aBinding); // This is the first time we've ever installed this binding on an element.
                                  // We need to go ahead and compile all methods and properties on a class
                                  // in our prototype binding.
     if (NS_FAILED(rv))
       return rv;
     MOZ_ASSERT(mPrecompiledMemberHolder);
   }
   nsIDocument *ownerDoc = aBoundElement->OwnerDoc();
   nsIGlobalObject *sgo;
   if (!(sgo = ownerDoc->GetScopeObject())) {
     return NS_ERROR_UNEXPECTED;
   }
   // Because our prototype implementation has a class, we need to build up a corresponding
   // class for the concrete implementation in the bound document.
   AutoJSContext cx;
   JS::Rooted<JSObject*> global(cx, sgo->GetGlobalJSObject());
   JS::Rooted<JS::Value> v(cx);
   JSAutoCompartment ac(cx, global);
   // Make sure the interface object is created before the prototype object
   // so that XULElement is hidden from content. See bug 909340.
   bool defineOnGlobal = dom::XULElementBinding::ConstructorEnabled(cx, global);
   dom::XULElementBinding::GetConstructorObject(cx, global, defineOnGlobal);
   rv = nsContentUtils::WrapNative(cx, aBoundElement, &v,
                                   /* aAllowWrapping = */ false);
   NS_ENSURE_SUCCESS(rv, rv);
   JS::Rooted<JSObject*> value(cx, &v.toObject());
   JSAutoCompartment ac2(cx, value);
   // All of the above code was just obtaining the bound element's script object and its immediate
   // concrete base class.  We need to alter the object so that our concrete class is interposed
   // between the object and its base class.  We become the new base class of the object, and the
   // object's old base class becomes the new class' base class.
   rv = aBinding->InitClass(mClassName, cx, value, aTargetClassObject, aTargetIsNew);
   if (NS_FAILED(rv)) {
     return rv;
   }
   aBoundElement->PreserveWrapper(aBoundElement);
   return rv;
 }
 nsresult
 nsXBLProtoImpl::CompilePrototypeMembers(nsXBLPrototypeBinding* aBinding)
 {
   // We want to pre-compile our implementation's members against a "prototype context". Then when we actually
   // bind the prototype to a real xbl instance, we'll clone the pre-compiled JS into the real instance's
   // context.
   AutoSafeJSContext cx;
   JS::Rooted<JSObject*> compilationGlobal(cx, xpc::GetCompilationScope());
   NS_ENSURE_TRUE(compilationGlobal, NS_ERROR_UNEXPECTED);
   JSAutoCompartment ac(cx, compilationGlobal);
   mPrecompiledMemberHolder = JS_NewObjectWithGivenProto(cx, nullptr, JS::NullPtr(), compilationGlobal);
   if (!mPrecompiledMemberHolder)
     return NS_ERROR_OUT_OF_MEMORY;
   // Now that we have a class object installed, we walk our member list and compile each of our
   // properties and methods in turn.
   JS::Rooted<JSObject*> rootedHolder(cx, mPrecompiledMemberHolder);
   for (nsXBLProtoImplMember* curr = mMembers;
        curr;
        curr = curr->GetNext()) {
     nsresult rv = curr->CompileMember(mClassName, rootedHolder);
     if (NS_FAILED(rv)) {
       DestroyMembers();
       return rv;
     }
   }
   return NS_OK;
 }
 bool
 nsXBLProtoImpl::LookupMember(JSContext* aCx, nsString& aName,
                              JS::Handle<jsid> aNameAsId,
                              JS::MutableHandle<JSPropertyDescriptor> aDesc,
                              JS::Handle<JSObject*> aClassObject)
 {
   for (nsXBLProtoImplMember* m = mMembers; m; m = m->GetNext()) {
     if (aName.Equals(m->GetName())) {
       return JS_GetPropertyDescriptorById(aCx, aClassObject, aNameAsId, aDesc);
     }
   }
   return true;
 }
 void
 nsXBLProtoImpl::Trace(const TraceCallbacks& aCallbacks, void *aClosure)
 {
   // If we don't have a class object then we either didn't compile members
   // or we only have fields, in both cases there are no cycles through our
   // members.
   if (!mPrecompiledMemberHolder) {
     return;
   }
   nsXBLProtoImplMember *member;
   for (member = mMembers; member; member = member->GetNext()) {
     member->Trace(aCallbacks, aClosure);
   }
 }
 void
 nsXBLProtoImpl::UnlinkJSObjects()
 {
   if (mPrecompiledMemberHolder) {
     DestroyMembers();
   }
 }
 nsXBLProtoImplField*
 nsXBLProtoImpl::FindField(const nsString& aFieldName) const
 {
   for (nsXBLProtoImplField* f = mFields; f; f = f->GetNext()) {
     if (aFieldName.Equals(f->GetName())) {
       return f;
     }
   }
   return nullptr;
 }
 bool
 nsXBLProtoImpl::ResolveAllFields(JSContext *cx, JS::Handle<JSObject*> obj) const
 {
   for (nsXBLProtoImplField* f = mFields; f; f = f->GetNext()) {
     // Using OBJ_LOOKUP_PROPERTY is a pain, since what we have is a
     // char16_t* for the property name.  Let's just use the public API and
     // all.
     nsDependentString name(f->GetName());
     JS::Rooted<JS::Value> dummy(cx);
     if (!::JS_LookupUCProperty(cx, obj, name.get(), name.Length(), &dummy)) {
       return false;
     }
   }
   return true;
 }
 void
 nsXBLProtoImpl::UndefineFields(JSContext *cx, JS::Handle<JSObject*> obj) const
 {
   JSAutoRequest ar(cx);
   for (nsXBLProtoImplField* f = mFields; f; f = f->GetNext()) {
     nsDependentString name(f->GetName());
     const jschar* s = name.get();
     bool hasProp;
     if (::JS_AlreadyHasOwnUCProperty(cx, obj, s, name.Length(), &hasProp) &&
         hasProp) {
       bool dummy;
       ::JS_DeleteUCProperty2(cx, obj, s, name.Length(), &dummy);
     }
   }
 }
 void
 nsXBLProtoImpl::DestroyMembers()
 {
   MOZ_ASSERT(mPrecompiledMemberHolder);
   delete mMembers;
   mMembers = nullptr;
   mConstructor = nullptr;
   mDestructor = nullptr;
 }
 nsresult
 nsXBLProtoImpl::Read(nsIObjectInputStream* aStream,
                      nsXBLPrototypeBinding* aBinding)
 {
   AssertInCompilationScope();
   AutoJSContext cx;
   // Set up a class object first so that deserialization is possible
   JS::Rooted<JSObject*> global(cx, JS::CurrentGlobalOrNull(cx));
   mPrecompiledMemberHolder = JS_NewObjectWithGivenProto(cx, nullptr, JS::NullPtr(), global);
   if (!mPrecompiledMemberHolder)
     return NS_ERROR_OUT_OF_MEMORY;
   nsXBLProtoImplField* previousField = nullptr;
   nsXBLProtoImplMember* previousMember = nullptr;
   do {
     XBLBindingSerializeDetails type;
     nsresult rv = aStream->Read8(&type);
     NS_ENSURE_SUCCESS(rv, rv);
     if (type == XBLBinding_Serialize_NoMoreItems)
       break;
     switch (type & XBLBinding_Serialize_Mask) {
       case XBLBinding_Serialize_Field:
       {
         nsXBLProtoImplField* field =
           new nsXBLProtoImplField(type & XBLBinding_Serialize_ReadOnly);
         rv = field->Read(aStream);
         if (NS_FAILED(rv)) {
           delete field;
           return rv;
         }
         if (previousField) {
           previousField->SetNext(field);
         }
         else {
           mFields = field;
         }
         previousField = field;
         break;
       }
       case XBLBinding_Serialize_GetterProperty:
       case XBLBinding_Serialize_SetterProperty:
       case XBLBinding_Serialize_GetterSetterProperty:
       {
         nsAutoString name;
         nsresult rv = aStream->ReadString(name);
         NS_ENSURE_SUCCESS(rv, rv);
         nsXBLProtoImplProperty* prop =
           new nsXBLProtoImplProperty(name.get(), type & XBLBinding_Serialize_ReadOnly);
         rv = prop->Read(aStream, type & XBLBinding_Serialize_Mask);
         if (NS_FAILED(rv)) {
           delete prop;
           return rv;
         }
         previousMember = AddMember(prop, previousMember);
         break;
       }
       case XBLBinding_Serialize_Method:
       {
         nsAutoString name;
         rv = aStream->ReadString(name);
         NS_ENSURE_SUCCESS(rv, rv);
         nsXBLProtoImplMethod* method = new nsXBLProtoImplMethod(name.get());
         rv = method->Read(aStream);
         if (NS_FAILED(rv)) {
           delete method;
           return rv;
         }
         previousMember = AddMember(method, previousMember);
         break;
       }
       case XBLBinding_Serialize_Constructor:
       {
         nsAutoString name;
         rv = aStream->ReadString(name);
         NS_ENSURE_SUCCESS(rv, rv);
         mConstructor = new nsXBLProtoImplAnonymousMethod(name.get());
         rv = mConstructor->Read(aStream);
         if (NS_FAILED(rv)) {
           delete mConstructor;
           mConstructor = nullptr;
           return rv;
         }
         previousMember = AddMember(mConstructor, previousMember);
         break;
       }
       case XBLBinding_Serialize_Destructor:
       {
         nsAutoString name;
         rv = aStream->ReadString(name);
         NS_ENSURE_SUCCESS(rv, rv);
         mDestructor = new nsXBLProtoImplAnonymousMethod(name.get());
         rv = mDestructor->Read(aStream);
         if (NS_FAILED(rv)) {
           delete mDestructor;
           mDestructor = nullptr;
           return rv;
         }
         previousMember = AddMember(mDestructor, previousMember);
         break;
       }
       default:
         NS_ERROR("Unexpected binding member type");
         break;
     }
   } while (1);
   return NS_OK;
 }
 nsresult
 nsXBLProtoImpl::Write(nsIObjectOutputStream* aStream,
                       nsXBLPrototypeBinding* aBinding)
 {
   nsresult rv;
   if (!mPrecompiledMemberHolder) {
     rv = CompilePrototypeMembers(aBinding);
     NS_ENSURE_SUCCESS(rv, rv);
   }
   rv = aStream->WriteStringZ(mClassName.get());
   NS_ENSURE_SUCCESS(rv, rv);
   for (nsXBLProtoImplField* curr = mFields; curr; curr = curr->GetNext()) {
     rv = curr->Write(aStream);
     NS_ENSURE_SUCCESS(rv, rv);
   }
   for (nsXBLProtoImplMember* curr = mMembers; curr; curr = curr->GetNext()) {
     if (curr == mConstructor) {
       rv = mConstructor->Write(aStream, XBLBinding_Serialize_Constructor);
     }
     else if (curr == mDestructor) {
       rv = mDestructor->Write(aStream, XBLBinding_Serialize_Destructor);
     }
     else {
       rv = curr->Write(aStream);
     }
     NS_ENSURE_SUCCESS(rv, rv);
   }
   return aStream->Write8(XBLBinding_Serialize_NoMoreItems);
 }
 nsresult
 NS_NewXBLProtoImpl(nsXBLPrototypeBinding* aBinding,
                    const char16_t* aClassName,
                    nsXBLProtoImpl** aResult)
 {
   nsXBLProtoImpl* impl = new nsXBLProtoImpl();
   if (!impl)
     return NS_ERROR_OUT_OF_MEMORY;
   if (aClassName)
     impl->mClassName.AssignWithConversion(aClassName);
   else
     aBinding->BindingURI()->GetSpec(impl->mClassName);
   aBinding->SetImplementation(impl);
   *aResult = impl;
   return NS_OK;
 }

The Tor Browser / annotate

dom/xbl/nsXBLProtoImpl.cpp@6474c204b198 (annotated)

dom/xbl/nsXBLProtoImpl.cpp