introduce evidence store

evidence/store.go

@@ -0,0 +1,100 @@
+package evpool
+
+import (
+	"fmt"
+
+	wire "github.com/tendermint/go-wire"
+	"github.com/tendermint/tendermint/types"
+	dbm "github.com/tendermint/tmlibs/db"
+)
+
+/*
+"evidence-lookup"/<evidence-height>/<evidence-hash> -> evidence struct
+"evidence-outqueue"/<index>/<evidence-height>/<evidence-hash> -> nil
+"evidence-pending"/<evidence-height>/evidence-hash> -> nil
+*/
+
+var nullValue = []byte{0}
+
+type evidenceInfo struct {
+	Committed bool
+	Priority  int
+	Evidence  types.Evidence
+}
+
+func keyLookup(evidence types.Evidence) []byte {
+	return []byte(fmt.Sprintf("evidence-lookup/%d/%X", evidence.Height(), evidence.Hash()))
+}
+
+func keyOutqueue(idx int, evidence types.Evidence) []byte {
+	return []byte(fmt.Sprintf("evidence-outqueue/%d/%d/%X", idx, evidence.Height(), evidence.Hash()))
+}
+
+func keyPending(evidence types.Evidence) []byte {
+	return []byte(fmt.Sprintf("evidence-pending/%d/%X", evidence.Height(), evidence.Hash()))
+}
+
+// EvidenceStore stores all the evidence we've seen, including
+// evidence that has been committed, evidence that has been seen but not broadcast,
+// and evidence that has been broadcast but not yet committed.
+type EvidenceStore struct {
+	chainID string
+	db      dbm.DB
+}
+
+func NewEvidenceStore(chainID string, db dbm.DB) *EvidenceStore {
+	return &EvidenceStore{
+		chainID: chainID,
+		db:      db,
+	}
+}
+
+// AddNewEvidence adds the given evidence to the database.
+func (store *EvidenceStore) AddNewEvidence(idx int, evidence types.Evidence) (bool, error) {
+	// check if we already have seen it
+	key := keyLookup(evidence)
+	v := store.db.Get(key)
+	if len(v) == 0 {
+		return false, nil
+	}
+
+	// verify the evidence
+	if err := evidence.Verify(store.chainID); err != nil {
+		return false, err
+	}
+
+	// add it to the store
+	ei := evidenceInfo{
+		Committed: false,
+		Priority:  idx,
+		Evidence:  evidence,
+	}
+	store.db.Set(key, wire.BinaryBytes(ei))
+
+	key = keyOutqueue(idx, evidence)
+	store.db.Set(key, nullValue)
+
+	key = keyPending(evidence)
+	store.db.Set(key, nullValue)
+
+	return true, nil
+}
+
+// MarkEvidenceAsBroadcasted removes evidence from the outqueue.
+func (store *EvidenceStore) MarkEvidenceAsBroadcasted(idx int, evidence types.Evidence) {
+	key := keyOutqueue(idx, evidence)
+	store.db.Delete(key)
+}
+
+// MarkEvidenceAsPending removes evidence from pending and sets the state to committed.
+func (store *EvidenceStore) MarkEvidenceAsCommitted(evidence types.Evidence) {
+	key := keyPending(evidence)
+	store.db.Delete(key)
+
+	key = keyLookup(evidence)
+	var ei evidenceInfo
+	b := store.db.Get(key)
+	wire.ReadBinaryBytes(b, &ei)
+	ei.Committed = true
+	store.db.Set(key, wire.BinaryBytes(ei))
+}