The Tor Browser: js/xpconnect/src/XPCWrappedNativeInfo.cpp@b8a032363ba2 (annotated)

js/xpconnect/src/XPCWrappedNativeInfo.cpp@b8a032363ba2 (annotated)

js/xpconnect/src/XPCWrappedNativeInfo.cpp

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- 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/. */
 /* Manage the shared info about interfaces for use by wrappedNatives. */
 #include "xpcprivate.h"
 #include "jswrapper.h"
 #include "nsCxPusher.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/XPTInterfaceInfoManager.h"
 using namespace JS;
 using namespace mozilla;
 /***************************************************************************/
 // XPCNativeMember
 // static
 bool
 XPCNativeMember::GetCallInfo(JSObject* funobj,
                              XPCNativeInterface** pInterface,
                              XPCNativeMember**    pMember)
 {
     funobj = js::UncheckedUnwrap(funobj);
     jsval ifaceVal = js::GetFunctionNativeReserved(funobj, 0);
     jsval memberVal = js::GetFunctionNativeReserved(funobj, 1);
     *pInterface = (XPCNativeInterface*) JSVAL_TO_PRIVATE(ifaceVal);
     *pMember = (XPCNativeMember*) JSVAL_TO_PRIVATE(memberVal);
     return true;
 }
 bool
 XPCNativeMember::NewFunctionObject(XPCCallContext& ccx,
                                    XPCNativeInterface* iface, HandleObject parent,
                                    jsval* pval)
 {
     MOZ_ASSERT(!IsConstant(), "Only call this if you're sure this is not a constant!");
     return Resolve(ccx, iface, parent, pval);
 }
 bool
 XPCNativeMember::Resolve(XPCCallContext& ccx, XPCNativeInterface* iface,
                          HandleObject parent, jsval *vp)
 {
     if (IsConstant()) {
         const nsXPTConstant* constant;
         if (NS_FAILED(iface->GetInterfaceInfo()->GetConstant(mIndex, &constant)))
             return false;
         const nsXPTCMiniVariant& mv = *constant->GetValue();
         // XXX Big Hack!
         nsXPTCVariant v;
         v.flags = 0;
         v.type = constant->GetType();
         memcpy(&v.val, &mv.val, sizeof(mv.val));
         RootedValue resultVal(ccx);
         if (!XPCConvert::NativeData2JS(&resultVal, &v.val, v.type, nullptr, nullptr))
             return false;
         *vp = resultVal;
         return true;
     }
     // else...
     // This is a method or attribute - we'll be needing a function object
     int argc;
     JSNative callback;
     if (IsMethod()) {
         const nsXPTMethodInfo* info;
         if (NS_FAILED(iface->GetInterfaceInfo()->GetMethodInfo(mIndex, &info)))
             return false;
         // Note: ASSUMES that retval is last arg.
         argc = (int) info->GetParamCount();
         if (argc && info->GetParam((uint8_t)(argc-1)).IsRetval())
             argc-- ;
         callback = XPC_WN_CallMethod;
     } else {
         argc = 0;
         callback = XPC_WN_GetterSetter;
     }
     JSFunction *fun = js::NewFunctionByIdWithReserved(ccx, callback, argc, 0, parent, GetName());
     if (!fun)
         return false;
     JSObject* funobj = JS_GetFunctionObject(fun);
     if (!funobj)
         return false;
     js::SetFunctionNativeReserved(funobj, 0, PRIVATE_TO_JSVAL(iface));
     js::SetFunctionNativeReserved(funobj, 1, PRIVATE_TO_JSVAL(this));
     *vp = OBJECT_TO_JSVAL(funobj);
     return true;
 }
 /***************************************************************************/
 // XPCNativeInterface
 // static
 XPCNativeInterface*
 XPCNativeInterface::GetNewOrUsed(const nsIID* iid)
 {
     AutoJSContext cx;
     AutoMarkingNativeInterfacePtr iface(cx);
     XPCJSRuntime* rt = XPCJSRuntime::Get();
     IID2NativeInterfaceMap* map = rt->GetIID2NativeInterfaceMap();
     if (!map)
         return nullptr;
     iface = map->Find(*iid);
     if (iface)
         return iface;
     nsCOMPtr<nsIInterfaceInfo> info;
     XPTInterfaceInfoManager::GetSingleton()->GetInfoForIID(iid, getter_AddRefs(info));
     if (!info)
         return nullptr;
     iface = NewInstance(info);
     if (!iface)
         return nullptr;
     XPCNativeInterface* iface2 = map->Add(iface);
     if (!iface2) {
         NS_ERROR("failed to add our interface!");
         DestroyInstance(iface);
         iface = nullptr;
     } else if (iface2 != iface) {
         DestroyInstance(iface);
         iface = iface2;
     }
     return iface;
 }
 // static
 XPCNativeInterface*
 XPCNativeInterface::GetNewOrUsed(nsIInterfaceInfo* info)
 {
     AutoJSContext cx;
     AutoMarkingNativeInterfacePtr iface(cx);
     const nsIID* iid;
     if (NS_FAILED(info->GetIIDShared(&iid)) || !iid)
         return nullptr;
     XPCJSRuntime* rt = XPCJSRuntime::Get();
     IID2NativeInterfaceMap* map = rt->GetIID2NativeInterfaceMap();
     if (!map)
         return nullptr;
     iface = map->Find(*iid);
     if (iface)
         return iface;
     iface = NewInstance(info);
     if (!iface)
         return nullptr;
     XPCNativeInterface* iface2 = map->Add(iface);
     if (!iface2) {
         NS_ERROR("failed to add our interface!");
         DestroyInstance(iface);
         iface = nullptr;
     } else if (iface2 != iface) {
         DestroyInstance(iface);
         iface = iface2;
     }
     return iface;
 }
 // static
 XPCNativeInterface*
 XPCNativeInterface::GetNewOrUsed(const char* name)
 {
     nsCOMPtr<nsIInterfaceInfo> info;
     XPTInterfaceInfoManager::GetSingleton()->GetInfoForName(name, getter_AddRefs(info));
     return info ? GetNewOrUsed(info) : nullptr;
 }
 // static
 XPCNativeInterface*
 XPCNativeInterface::GetISupports()
 {
     // XXX We should optimize this to cache this common XPCNativeInterface.
     return GetNewOrUsed(&NS_GET_IID(nsISupports));
 }
 // static
 XPCNativeInterface*
 XPCNativeInterface::NewInstance(nsIInterfaceInfo* aInfo)
 {
     AutoJSContext cx;
     static const uint16_t MAX_LOCAL_MEMBER_COUNT = 16;
     XPCNativeMember local_members[MAX_LOCAL_MEMBER_COUNT];
     XPCNativeInterface* obj = nullptr;
     XPCNativeMember* members = nullptr;
     int i;
     bool failed = false;
     uint16_t constCount;
     uint16_t methodCount;
     uint16_t totalCount;
     uint16_t realTotalCount = 0;
     XPCNativeMember* cur;
     RootedString str(cx);
     RootedId interfaceName(cx);
     // XXX Investigate lazy init? This is a problem given the
     // 'placement new' scheme - we need to at least know how big to make
     // the object. We might do a scan of methods to determine needed size,
     // then make our object, but avoid init'ing *any* members until asked?
     // Find out how often we create these objects w/o really looking at
     // (or using) the members.
     bool canScript;
     if (NS_FAILED(aInfo->IsScriptable(&canScript)) || !canScript)
         return nullptr;
     if (NS_FAILED(aInfo->GetMethodCount(&methodCount)) ||
         NS_FAILED(aInfo->GetConstantCount(&constCount)))
         return nullptr;
     // 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) {
         members = new XPCNativeMember[totalCount];
         if (!members)
             return nullptr;
     } else {
         members = local_members;
     }
     // NOTE: since getters and setters share a member, we might not use all
     // of the member objects.
     for (i = 0; i < methodCount; i++) {
         const nsXPTMethodInfo* info;
         if (NS_FAILED(aInfo->GetMethodInfo(i, &info))) {
             failed = true;
             break;
         }
         // don't reflect Addref or Release
         if (i == 1 || i == 2)
             continue;
         if (!XPCConvert::IsMethodReflectable(*info))
             continue;
         str = JS_InternString(cx, info->GetName());
         if (!str) {
             NS_ERROR("bad method name");
             failed = true;
             break;
         }
         jsid name = INTERNED_STRING_TO_JSID(cx, str);
         if (info->IsSetter()) {
             MOZ_ASSERT(realTotalCount,"bad setter");
             // Note: ASSUMES Getter/Setter pairs are next to each other
             // This is a rule of the typelib spec.
             cur = &members[realTotalCount-1];
             MOZ_ASSERT(cur->GetName() == name,"bad setter");
             MOZ_ASSERT(cur->IsReadOnlyAttribute(),"bad setter");
             MOZ_ASSERT(cur->GetIndex() == i-1,"bad setter");
             cur->SetWritableAttribute();
         } else {
             // XXX need better way to find dups
             // MOZ_ASSERT(!LookupMemberByID(name),"duplicate method name");
             cur = &members[realTotalCount++];
             cur->SetName(name);
             if (info->IsGetter())
                 cur->SetReadOnlyAttribute(i);
             else
                 cur->SetMethod(i);
         }
     }
     if (!failed) {
         for (i = 0; i < constCount; i++) {
             const nsXPTConstant* constant;
             if (NS_FAILED(aInfo->GetConstant(i, &constant))) {
                 failed = true;
                 break;
             }
             str = JS_InternString(cx, constant->GetName());
             if (!str) {
                 NS_ERROR("bad constant name");
                 failed = true;
                 break;
             }
             jsid name = INTERNED_STRING_TO_JSID(cx, str);
             // XXX need better way to find dups
             //MOZ_ASSERT(!LookupMemberByID(name),"duplicate method/constant name");
             cur = &members[realTotalCount++];
             cur->SetName(name);
             cur->SetConstant(i);
         }
     }
     if (!failed) {
         const char* bytes;
         if (NS_FAILED(aInfo->GetNameShared(&bytes)) || !bytes ||
             nullptr == (str = JS_InternString(cx, bytes))) {
             failed = true;
         }
         interfaceName = INTERNED_STRING_TO_JSID(cx, str);
     }
     if (!failed) {
         // Use placement new to create an object with the right amount of space
         // to hold the members array
         int size = sizeof(XPCNativeInterface);
         if (realTotalCount > 1)
             size += (realTotalCount - 1) * sizeof(XPCNativeMember);
         void* place = new char[size];
         if (place)
             obj = new(place) XPCNativeInterface(aInfo, interfaceName);
         if (obj) {
             obj->mMemberCount = realTotalCount;
             // copy valid members
             if (realTotalCount)
                 memcpy(obj->mMembers, members,
                        realTotalCount * sizeof(XPCNativeMember));
         }
     }
     if (members && members != local_members)
         delete [] members;
     return obj;
 }
 // static
 void
 XPCNativeInterface::DestroyInstance(XPCNativeInterface* inst)
 {
     inst->~XPCNativeInterface();
     delete [] (char*) inst;
 }
 size_t
 XPCNativeInterface::SizeOfIncludingThis(MallocSizeOf mallocSizeOf)
 {
     return mallocSizeOf(this);
 }
 void
 XPCNativeInterface::DebugDump(int16_t depth)
 {
 #ifdef DEBUG
     depth--;
     XPC_LOG_ALWAYS(("XPCNativeInterface @ %x", this));
         XPC_LOG_INDENT();
         XPC_LOG_ALWAYS(("name is %s", GetNameString()));
         XPC_LOG_ALWAYS(("mMemberCount is %d", mMemberCount));
         XPC_LOG_ALWAYS(("mInfo @ %x", mInfo.get()));
         XPC_LOG_OUTDENT();
 #endif
 }
 /***************************************************************************/
 // XPCNativeSet
 // static
 XPCNativeSet*
 XPCNativeSet::GetNewOrUsed(const nsIID* iid)
 {
     AutoJSContext cx;
     AutoMarkingNativeSetPtr set(cx);
     AutoMarkingNativeInterfacePtr iface(cx);
     iface = XPCNativeInterface::GetNewOrUsed(iid);
     if (!iface)
         return nullptr;
     XPCNativeSetKey key(nullptr, iface, 0);
     XPCJSRuntime* rt = XPCJSRuntime::Get();
     NativeSetMap* map = rt->GetNativeSetMap();
     if (!map)
         return nullptr;
     set = map->Find(&key);
     if (set)
         return set;
     // hacky way to get a XPCNativeInterface** using the AutoPtr
     XPCNativeInterface* temp[] = {iface};
     set = NewInstance(temp, 1);
     if (!set)
         return nullptr;
     XPCNativeSet* set2 = map->Add(&key, set);
     if (!set2) {
         NS_ERROR("failed to add our set!");
         DestroyInstance(set);
         set = nullptr;
     } else if (set2 != set) {
         DestroyInstance(set);
         set = set2;
     }
     return set;
 }
 // static
 XPCNativeSet*
 XPCNativeSet::GetNewOrUsed(nsIClassInfo* classInfo)
 {
     AutoJSContext cx;
     AutoMarkingNativeSetPtr set(cx);
     XPCJSRuntime* rt = XPCJSRuntime::Get();
     ClassInfo2NativeSetMap* map = rt->GetClassInfo2NativeSetMap();
     if (!map)
         return nullptr;
     set = map->Find(classInfo);
     if (set)
         return set;
     nsIID** iidArray = nullptr;
     AutoMarkingNativeInterfacePtrArrayPtr interfaceArray(cx);
     uint32_t iidCount = 0;
     if (NS_FAILED(classInfo->GetInterfaces(&iidCount, &iidArray))) {
         // Note: I'm making it OK for this call to fail so that one can add
         // nsIClassInfo to classes implemented in script without requiring this
         // method to be implemented.
         // Make sure these are set correctly...
         iidArray = nullptr;
         iidCount = 0;
     }
     MOZ_ASSERT((iidCount && iidArray) || !(iidCount || iidArray), "GetInterfaces returned bad array");
     // !!! from here on we only exit through the 'out' label !!!
     if (iidCount) {
         AutoMarkingNativeInterfacePtrArrayPtr
             arr(cx, new XPCNativeInterface*[iidCount], iidCount, true);
         interfaceArray = arr;
         XPCNativeInterface** currentInterface = interfaceArray;
         nsIID**              currentIID = iidArray;
         uint16_t             interfaceCount = 0;
         for (uint32_t i = 0; i < iidCount; i++) {
             nsIID* iid = *(currentIID++);
             if (!iid) {
                 NS_ERROR("Null found in classinfo interface list");
                 continue;
             }
             XPCNativeInterface* iface =
                 XPCNativeInterface::GetNewOrUsed(iid);
             if (!iface) {
                 // XXX warn here
                 continue;
             }
             *(currentInterface++) = iface;
             interfaceCount++;
         }
         if (interfaceCount) {
             set = NewInstance(interfaceArray, interfaceCount);
             if (set) {
                 NativeSetMap* map2 = rt->GetNativeSetMap();
                 if (!map2)
                     goto out;
                 XPCNativeSetKey key(set, nullptr, 0);
                 XPCNativeSet* set2 = map2->Add(&key, set);
                 if (!set2) {
                     NS_ERROR("failed to add our set!");
                     DestroyInstance(set);
                     set = nullptr;
                     goto out;
                 }
                 if (set2 != set) {
                     DestroyInstance(set);
                     set = set2;
                 }
             }
         } else
             set = GetNewOrUsed(&NS_GET_IID(nsISupports));
     } else
         set = GetNewOrUsed(&NS_GET_IID(nsISupports));
     if (set) {
 #ifdef DEBUG
         XPCNativeSet* set2 =
 #endif
           map->Add(classInfo, set);
         MOZ_ASSERT(set2, "failed to add our set!");
         MOZ_ASSERT(set2 == set, "hashtables inconsistent!");
     }
 out:
     if (iidArray)
         NS_FREE_XPCOM_ALLOCATED_POINTER_ARRAY(iidCount, iidArray);
     if (interfaceArray)
         delete [] interfaceArray.get();
     return set;
 }
 // static
 void
 XPCNativeSet::ClearCacheEntryForClassInfo(nsIClassInfo* classInfo)
 {
     XPCJSRuntime* rt = nsXPConnect::GetRuntimeInstance();
     ClassInfo2NativeSetMap* map = rt->GetClassInfo2NativeSetMap();
     if (map)
         map->Remove(classInfo);
 }
 // static
 XPCNativeSet*
 XPCNativeSet::GetNewOrUsed(XPCNativeSet* otherSet,
                            XPCNativeInterface* newInterface,
                            uint16_t position)
 {
     AutoJSContext cx;
     AutoMarkingNativeSetPtr set(cx);
     XPCJSRuntime* rt = XPCJSRuntime::Get();
     NativeSetMap* map = rt->GetNativeSetMap();
     if (!map)
         return nullptr;
     XPCNativeSetKey key(otherSet, newInterface, position);
     set = map->Find(&key);
     if (set)
         return set;
     if (otherSet)
         set = NewInstanceMutate(otherSet, newInterface, position);
     else
         set = NewInstance(&newInterface, 1);
     if (!set)
         return nullptr;
     XPCNativeSet* set2 = map->Add(&key, set);
     if (!set2) {
         NS_ERROR("failed to add our set!");
         DestroyInstance(set);
         set = nullptr;
     } else if (set2 != set) {
         DestroyInstance(set);
         set = set2;
     }
     return set;
 }
 // static
 XPCNativeSet*
 XPCNativeSet::GetNewOrUsed(XPCNativeSet* firstSet,
                            XPCNativeSet* secondSet,
                            bool preserveFirstSetOrder)
 {
     // Figure out how many interfaces we'll need in the new set.
     uint32_t uniqueCount = firstSet->mInterfaceCount;
     for (uint32_t 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 (uint32_t 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.
             uint32_t pos = currentSet->mInterfaceCount;
             currentSet = XPCNativeSet::GetNewOrUsed(currentSet, iface, pos);
             if (!currentSet)
                 return nullptr;
         }
     }
     // We've got the union set. Hand it back to the caller.
     MOZ_ASSERT(currentSet->mInterfaceCount == uniqueCount);
     return currentSet;
 }
 // static
 XPCNativeSet*
 XPCNativeSet::NewInstance(XPCNativeInterface** array,
                           uint16_t count)
 {
     XPCNativeSet* obj = nullptr;
     if (!array || !count)
         return nullptr;
     // We impose the invariant:
     // "All sets have exactly one nsISupports interface and it comes first."
     // This is the place where we impose that rule - even if given inputs
     // that don't exactly follow the rule.
     XPCNativeInterface* isup = XPCNativeInterface::GetISupports();
     uint16_t slots = count+1;
     uint16_t i;
     XPCNativeInterface** pcur;
     for (i = 0, pcur = array; i < count; i++, pcur++) {
         if (*pcur == isup)
             slots--;
     }
     // Use placement new to create an object with the right amount of space
     // to hold the members array
     int size = sizeof(XPCNativeSet);
     if (slots > 1)
         size += (slots - 1) * sizeof(XPCNativeInterface*);
     void* place = new char[size];
     if (place)
         obj = new(place) XPCNativeSet();
     if (obj) {
         // Stick the nsISupports in front and skip additional nsISupport(s)
         XPCNativeInterface** inp = array;
         XPCNativeInterface** outp = (XPCNativeInterface**) &obj->mInterfaces;
         uint16_t memberCount = 1;   // for the one member in nsISupports
         *(outp++) = isup;
         for (i = 0; i < count; i++) {
             XPCNativeInterface* cur;
             if (isup == (cur = *(inp++)))
                 continue;
             *(outp++) = cur;
             memberCount += cur->GetMemberCount();
         }
         obj->mMemberCount = memberCount;
         obj->mInterfaceCount = slots;
     }
     return obj;
 }
 // static
 XPCNativeSet*
 XPCNativeSet::NewInstanceMutate(XPCNativeSet*       otherSet,
                                 XPCNativeInterface* newInterface,
                                 uint16_t            position)
 {
     XPCNativeSet* obj = nullptr;
     if (!newInterface)
         return nullptr;
     if (otherSet && position > otherSet->mInterfaceCount)
         return nullptr;
     // Use placement new to create an object with the right amount of space
     // to hold the members array
     int size = sizeof(XPCNativeSet);
     if (otherSet)
         size += otherSet->mInterfaceCount * sizeof(XPCNativeInterface*);
     void* place = new char[size];
     if (place)
         obj = new(place) XPCNativeSet();
     if (obj) {
         if (otherSet) {
             obj->mMemberCount = otherSet->GetMemberCount() +
                                 newInterface->GetMemberCount();
             obj->mInterfaceCount = otherSet->mInterfaceCount + 1;
             XPCNativeInterface** src = otherSet->mInterfaces;
             XPCNativeInterface** dest = obj->mInterfaces;
             for (uint16_t i = 0; i < obj->mInterfaceCount; i++) {
                 if (i == position)
                     *dest++ = newInterface;
                 else
                     *dest++ = *src++;
             }
         } else {
             obj->mMemberCount = newInterface->GetMemberCount();
             obj->mInterfaceCount = 1;
             obj->mInterfaces[0] = newInterface;
         }
     }
     return obj;
 }
 // static
 void
 XPCNativeSet::DestroyInstance(XPCNativeSet* inst)
 {
     inst->~XPCNativeSet();
     delete [] (char*) inst;
 }
 size_t
 XPCNativeSet::SizeOfIncludingThis(MallocSizeOf mallocSizeOf)
 {
     return mallocSizeOf(this);
 }
 void
 XPCNativeSet::DebugDump(int16_t depth)
 {
 #ifdef DEBUG
     depth--;
     XPC_LOG_ALWAYS(("XPCNativeSet @ %x", this));
         XPC_LOG_INDENT();
         XPC_LOG_ALWAYS(("mInterfaceCount of %d", mInterfaceCount));
         if (depth) {
             for (uint16_t i = 0; i < mInterfaceCount; i++)
                 mInterfaces[i]->DebugDump(depth);
         }
         XPC_LOG_ALWAYS(("mMemberCount of %d", mMemberCount));
         XPC_LOG_OUTDENT();
 #endif
 }

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js/xpconnect/src/XPCWrappedNativeInfo.cpp@b8a032363ba2 (annotated)

js/xpconnect/src/XPCWrappedNativeInfo.cpp