static already_AddRefed<SharedMemory>
ReadSegment(const IPC::Message& aDescriptor, Shmem::id_t* aId, size_t* aNBytes, size_t aExtraSize)
{
if (SHMEM_CREATED_MESSAGE_TYPE != aDescriptor.type()) {
NS_ERROR("expected 'shmem created' message");
return nullptr;
}
SharedMemory::SharedMemoryType type;
PickleIterator iter(aDescriptor);
if (!ShmemCreated::ReadInfo(&aDescriptor, &iter, aId, aNBytes, &type)) {
return nullptr;
}
RefPtr<SharedMemory> segment = NewSegment(type);
if (!segment) {
return nullptr;
}
if (!segment->ReadHandle(&aDescriptor, &iter)) {
NS_ERROR("trying to open invalid handle");
return nullptr;
}
aDescriptor.EndRead(iter);
size_t size = SharedMemory::PageAlignedSize(*aNBytes + aExtraSize);
if (!segment->Map(size)) {
return nullptr;
}
// close the handle to the segment after it is mapped
segment->CloseHandle();
return segment.forget();
}
static bool Read(const IPC::Message& aMsg,
TransportDescriptor* aDescriptor,
ProcessId* aOtherProcess,
ProtocolId* aProtocol)
{
void* iter = nullptr;
if (!IPC::ReadParam(&aMsg, &iter, aDescriptor) ||
!IPC::ReadParam(&aMsg, &iter, aOtherProcess) ||
!IPC::ReadParam(&aMsg, &iter, reinterpret_cast<uint32_t*>(aProtocol))) {
return false;
}
aMsg.EndRead(iter);
return true;
}