Handle Tendermint messages

consensus/tendermint/messages.go

@@ -0,0 +1,126 @@
+package tendermint
+
+// Todo: Signature over the messages needs to be handled somewhere. There are 2 options:
+//	1. Add the signature to each message and extend the Validator Set interface to include VerifyMessageSignature
+//	method.
+//	2. The P2P layer signs the message before gossiping to other validators and verifies the signature before passing
+//	the message to the consensus engine.
+//  The benefit of P2P layer handling the verification of the signature is the that the consensus layer can assume
+//  the message is from a validator in the validator set. However, this means that the P2P layer would need to be aware
+//  of the validator set and would need access to the blockchain which may not be a good idea.
+
+type Message[V Hashable[H], H Hash, A Addr] interface {
+	Proposal[V, H, A] | Prevote[H, A] | Precommit[H, A]
+}
+
+type Proposal[V Hashable[H], H Hash, A Addr] struct {
+	Height     uint
+	Round      uint
+	ValidRound *uint
+	Value      *V
+
+	Sender A
+}
+
+type Prevote[H Hash, A Addr] struct {
+	Vote[H, A]
+}
+
+type Precommit[H Hash, A Addr] struct {
+	Vote[H, A]
+}
+
+type Vote[H Hash, A Addr] struct {
+	Height uint
+	Round  uint
+	ID     *H
+
+	Sender A
+}
+
+// messages keep tracks of all the proposals, prevotes, precommits by creating a map structure as follows:
+// height->round->address->[]Message
+
+// Todo: would the following representation of message be better:
+//
+//	  height -> round -> address -> ID -> Message
+//	How would we keep track of nil votes? In golan map key cannot be nil.
+//	It is not easy to calculate a zero value when dealing with generics.
+type messages[V Hashable[H], H Hash, A Addr] struct {
+	proposals  map[uint]map[uint]map[A][]Proposal[V, H, A]
+	prevotes   map[uint]map[uint]map[A][]Prevote[H, A]
+	precommits map[uint]map[uint]map[A][]Precommit[H, A]
+}
+
+func newMessages[V Hashable[H], H Hash, A Addr]() messages[V, H, A] {
+	return messages[V, H, A]{
+		proposals:  make(map[uint]map[uint]map[A][]Proposal[V, H, A]),
+		prevotes:   make(map[uint]map[uint]map[A][]Prevote[H, A]),
+		precommits: make(map[uint]map[uint]map[A][]Precommit[H, A]),
+	}
+}
+
+// Todo: ensure duplicated messages are ignored.
+func (m *messages[V, H, A]) addProposal(p Proposal[V, H, A]) {
+	if _, ok := m.proposals[p.Height]; !ok {
+		m.proposals[p.Height] = make(map[uint]map[A][]Proposal[V, H, A])
+	}
+
+	if _, ok := m.proposals[p.Height][p.Round]; !ok {
+		m.proposals[p.Height][p.Round] = make(map[A][]Proposal[V, H, A])
+	}
+
+	sendersProposals, ok := m.proposals[p.Height][p.Round][p.Sender]
+	if !ok {
+		sendersProposals = []Proposal[V, H, A]{}
+	}
+
+	m.proposals[p.Height][p.Round][p.Sender] = append(sendersProposals, p)
+}
+
+func (m *messages[V, H, A]) addPrevote(p Prevote[H, A]) {
+	if _, ok := m.prevotes[p.Height]; !ok {
+		m.prevotes[p.Height] = make(map[uint]map[A][]Prevote[H, A])
+	}
+
+	if _, ok := m.prevotes[p.Height][p.Round]; !ok {
+		m.prevotes[p.Height][p.Round] = make(map[A][]Prevote[H, A])
+	}
+
+	sendersPrevotes, ok := m.prevotes[p.Height][p.Round][p.Sender]
+	if !ok {
+		sendersPrevotes = []Prevote[H, A]{}
+	}
+
+	m.prevotes[p.Height][p.Round][p.Sender] = append(sendersPrevotes, p)
+}
+
+func (m *messages[V, H, A]) addPrecommit(p Precommit[H, A]) {
+	if _, ok := m.precommits[p.Height]; !ok {
+		m.precommits[p.Height] = make(map[uint]map[A][]Precommit[H, A])
+	}
+
+	if _, ok := m.precommits[p.Height][p.Round]; !ok {
+		m.precommits[p.Height][p.Round] = make(map[A][]Precommit[H, A])
+	}
+
+	sendersPrecommits, ok := m.precommits[p.Height][p.Round][p.Sender]
+	if !ok {
+		sendersPrecommits = []Precommit[H, A]{}
+	}
+
+	m.precommits[p.Height][p.Round][p.Sender] = append(sendersPrecommits, p)
+}
+
+func (m *messages[V, H, A]) allMessages(h, r uint) (map[A][]Proposal[V, H, A], map[A][]Prevote[H, A],
+	map[A][]Precommit[H, A],
+) {
+	// Todo: Should they be copied?
+	return m.proposals[h][r], m.prevotes[h][r], m.precommits[h][r]
+}
+
+func (m *messages[V, H, A]) deleteOldMessages(h uint) {
+	delete(m.proposals, h)
+	delete(m.prevotes, h)
+	delete(m.precommits, h)
+}