// Must be called from the processing goroutine, inside a transaction.
// Returns false if it discarded the accepted message because of it being
// too far in our future. Any other reason for discarding the message,
// as well as the accept succeeding, will return true.
func addAccepted(node uint16, accepted *coproto.Accepted) bool {
slots := store.InstructionSlots()
msgProposal, msgLeader := *accepted.Proposal, uint16(*accepted.Leader)
newReq := accepted.Instruction.Request
slot := *accepted.Instruction.Slot
ourStart := store.InstructionStart()
relativeSlot := int(slot - ourStart)
// If our instruction slot slice is not this long,
// we know we do not have any value in this slot yet,
// and so need to add a new one.
if len(slots) <= relativeSlot {
chreq := makeExtChangeRequest(newReq)
newInst := store.AddInstructionValue(slot, chreq)
if newInst == nil {
return false
}
newInst.Accept(node, msgProposal, msgLeader)
return true
}
// If we have already chosen an instruction in this slot,
// we can ignore subsequent Accepted messages for it.
if len(slots[relativeSlot]) == 1 && slots[relativeSlot][0].IsChosen() {
return true
}
// Returns if it successfully finds an existing matching value.
for _, value := range slots[relativeSlot] {
chreq := value.ChangeRequest()
if chreq.RequestNode != uint16(*newReq.RequestNode) {
continue
}
if chreq.RequestId != *newReq.RequestId {
continue
}
value.Accept(node, msgProposal, msgLeader)
return true
}
chreq := makeExtChangeRequest(newReq)
newInst := store.AddInstructionValue(slot, chreq)
if newInst == nil {
return false
}
newInst.Accept(node, msgProposal, msgLeader)
return true
}
func handleInstructionData(f *followConn, content []byte) {
store.StartTransaction()
defer store.EndTransaction()
f.lock.Lock()
if f.closed {
f.lock.Unlock()
return
}
var msg fproto.InstructionData
if err := proto.Unmarshal(content, &msg); err != nil {
f.Close()
f.lock.Unlock()
return
}
if f.receivingBurst {
f.waiting = append(f.waiting, &msg)
f.lock.Unlock()
return
}
// We need to unlock before we start mutating the store,
// due to callbacks from the store package to elsewhere.
f.lock.Unlock()
// If we have a chosen instruction in this slot already,
// or it is prior to our instruction start number,
// discard this message.
relativeSlot := int(*msg.Slot - store.InstructionStart())
if relativeSlot < 0 {
return
}
instructions := store.InstructionSlots()
if relativeSlot < len(instructions) &&
len(instructions[relativeSlot]) == 1 &&
instructions[relativeSlot][0].IsChosen() {
return
}
// Construct a store.ChangeRequest from our
// internal ChangeRequest.
chrequest := new(store.ChangeRequest)
chrequest.RequestEntity = *msg.Request.RequestEntity
chrequest.RequestNode = uint16(*msg.Request.RequestNode)
chrequest.RequestId = *msg.Request.RequestId
chrequest.Changeset = make([]store.Change,
len(msg.Request.Changeset))
for i, ch := range msg.Request.Changeset {
chrequest.Changeset[i].TargetEntity = *ch.TargetEntity
chrequest.Changeset[i].Key = *ch.Key
chrequest.Changeset[i].Value = *ch.Value
}
// Add instruction value and immediately choose it.
store.AddInstructionValue(*msg.Slot, chrequest).Choose()
}