Add a light-client provider in the kvstore

modules/ibc/provider.go

@@ -1,17 +1,24 @@
 package ibc
 
 import (
+	wire "github.com/tendermint/go-wire"
 	"github.com/tendermint/light-client/certifiers"
 
 	"github.com/tendermint/basecoin/stack"
 	"github.com/tendermint/basecoin/state"
 )
 
+const (
+	prefixHash   = "v"
+	prefixHeight = "h"
+	prefixPacket = "p"
+)
+
 // newCertifier loads up the current state of this chain to make a proper
 func newCertifier(chainID string, store state.KVStore) (*certifiers.InquiringCertifier, error) {
 	// each chain has their own prefixed subspace
 	space := stack.PrefixedStore(chainID, store)
-	p := dbProvider{space}
+	p := newDBProvider(space)
 
 	// this gets the most recent verified seed
 	seed, err := certifiers.LatestSeed(p)
@@ -27,18 +34,41 @@ func newCertifier(chainID string, store state.KVStore) (*certifiers.InquiringCer
 
 // dbProvider wraps our kv store so it integrates with light-client verification
 type dbProvider struct {
-	store state.KVStore
+	byHash   state.KVStore
+	byHeight *state.Span
 }
 
-var _ certifiers.Provider = dbProvider{}
+func newDBProvider(store state.KVStore) *dbProvider {
+	return &dbProvider{
+		byHash:   stack.PrefixedStore(prefixHash, store),
+		byHeight: state.NewSpan(stack.PrefixedStore(prefixHeight, store)),
+	}
+}
 
-func (d dbProvider) StoreSeed(seed certifiers.Seed) error {
+var _ certifiers.Provider = &dbProvider{}
+
+func (d *dbProvider) StoreSeed(seed certifiers.Seed) error {
+	// TODO: don't duplicate data....
+	b := wire.BinaryBytes(seed)
+	d.byHash.Set(seed.Hash(), b)
+	d.byHeight.Set(uint64(seed.Height()), b)
 	return nil
 }
 
-func (d dbProvider) GetByHeight(h int) (certifiers.Seed, error) {
+func (d *dbProvider) GetByHeight(h int) (seed certifiers.Seed, err error) {
-	return certifiers.Seed{}, certifiers.ErrSeedNotFound()
+	b, _ := d.byHeight.LTE(uint64(h))
+	if b == nil {
+		return seed, certifiers.ErrSeedNotFound()
+	}
+	err = wire.ReadBinaryBytes(b, &seed)
+	return
 }
-func (d dbProvider) GetByHash(hash []byte) (certifiers.Seed, error) {
+
-	return certifiers.Seed{}, certifiers.ErrSeedNotFound()
+func (d *dbProvider) GetByHash(hash []byte) (seed certifiers.Seed, err error) {
+	b := d.byHash.Get(hash)
+	if b == nil {
+		return seed, certifiers.ErrSeedNotFound()
+	}
+	err = wire.ReadBinaryBytes(b, &seed)
+	return
 }

modules/ibc/provider_test.go

@@ -0,0 +1,136 @@
+package ibc
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/tendermint/basecoin/state"
+	"github.com/tendermint/light-client/certifiers"
+)
+
+func assertSeedEqual(t *testing.T, s, s2 certifiers.Seed) {
+	assert := assert.New(t)
+	assert.Equal(s.Height(), s2.Height())
+	assert.Equal(s.Hash(), s2.Hash())
+	// TODO: more
+}
+
+func TestProviderStore(t *testing.T) {
+	assert, require := assert.New(t), require.New(t)
+
+	// make a few seeds
+	keys := certifiers.GenValKeys(2)
+	seeds := makeSeeds(keys, 4, "some-chain", "demo-store")
+
+	// make a provider
+	store := state.NewMemKVStore()
+	p := newDBProvider(store)
+
+	// check it...
+	_, err := p.GetByHeight(20)
+	require.NotNil(err)
+	assert.True(certifiers.IsSeedNotFoundErr(err))
+
+	// add a seed
+	for _, s := range seeds {
+		err = p.StoreSeed(s)
+		require.Nil(err)
+	}
+
+	// make sure we get it...
+	s := seeds[0]
+	val, err := p.GetByHeight(s.Height())
+	if assert.Nil(err) {
+		assertSeedEqual(t, s, val)
+	}
+
+	// make sure we get higher
+	val, err = p.GetByHeight(s.Height() + 2)
+	if assert.Nil(err) {
+		assertSeedEqual(t, s, val)
+	}
+
+	// below is nothing
+	_, err = p.GetByHeight(s.Height() - 2)
+	assert.True(certifiers.IsSeedNotFoundErr(err))
+
+	// make sure we get highest
+	val, err = certifiers.LatestSeed(p)
+	if assert.Nil(err) {
+		assertSeedEqual(t, seeds[3], val)
+	}
+
+	// make sure by hash also (note all have same hash, so overwritten)
+	val, err = p.GetByHash(seeds[1].Hash())
+	if assert.Nil(err) {
+		assertSeedEqual(t, seeds[3], val)
+	}
+}
+
+func TestDBProvider(t *testing.T) {
+	store := state.NewMemKVStore()
+	p := newDBProvider(store)
+	checkProvider(t, p, "test-db", "bling")
+}
+
+func makeSeeds(keys certifiers.ValKeys, count int, chainID, app string) []certifiers.Seed {
+	appHash := []byte(app)
+	seeds := make([]certifiers.Seed, count)
+	for i := 0; i < count; i++ {
+		// two seeds for each validator, to check how we handle dups
+		// (10, 0), (10, 1), (10, 1), (10, 2), (10, 2), ...
+		vals := keys.ToValidators(10, int64(count/2))
+		h := 20 + 10*i
+		check := keys.GenCheckpoint(chainID, h, nil, vals, appHash, 0, len(keys))
+		seeds[i] = certifiers.Seed{check, vals}
+	}
+	return seeds
+}
+
+func checkProvider(t *testing.T, p certifiers.Provider, chainID, app string) {
+	assert, require := assert.New(t), require.New(t)
+	keys := certifiers.GenValKeys(5)
+	count := 10
+
+	// make a bunch of seeds...
+	seeds := makeSeeds(keys, count, chainID, app)
+
+	// check provider is empty
+	seed, err := p.GetByHeight(20)
+	require.NotNil(err)
+	assert.True(certifiers.IsSeedNotFoundErr(err))
+
+	seed, err = p.GetByHash(seeds[3].Hash())
+	require.NotNil(err)
+	assert.True(certifiers.IsSeedNotFoundErr(err))
+
+	// now add them all to the provider
+	for _, s := range seeds {
+		err = p.StoreSeed(s)
+		require.Nil(err)
+		// and make sure we can get it back
+		s2, err := p.GetByHash(s.Hash())
+		assert.Nil(err)
+		assertSeedEqual(t, s, s2)
+		// by height as well
+		s2, err = p.GetByHeight(s.Height())
+		assert.Nil(err)
+		assertSeedEqual(t, s, s2)
+	}
+
+	// make sure we get the last hash if we overstep
+	seed, err = p.GetByHeight(5000)
+	if assert.Nil(err) {
+		assertSeedEqual(t, seeds[count-1], seed)
+	}
+
+	// and middle ones as well
+	seed, err = p.GetByHeight(47)
+	if assert.Nil(err) {
+		// we only step by 10, so 40 must be the one below this
+		assert.Equal(40, seed.Height())
+	}
+
+}