Denom traces migration

Author: MissingNO57

app/traces/traces.go

@@ -0,0 +1,99 @@
+package traces
+
+import (
+	"fmt"
+
+	storetypes "cosmossdk.io/store/types"
+	"github.com/cosmos/cosmos-sdk/codec"
+	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	ibctransfertypes "github.com/cosmos/ibc-go/v10/modules/apps/transfer/types"
+)
+
+func NewDenomTracesMigrator(ibcStore storetypes.KVStore) DenomTracesMigrator {
+	return DenomTracesMigrator{ibcStore: ibcStore}
+}
+
+// DenomTraces is a struct for handling in-place store migrations.
+type DenomTracesMigrator struct {
+	ibcStore storetypes.KVStore
+}
+
+func equalTraces(dtA, dtB DenomTrace) bool {
+	return dtA.BaseDenom == dtB.BaseDenom && dtA.Path == dtB.Path
+}
+
+// IterateDenomTraces iterates over the denomination traces in the store
+// and performs a callback function.
+func (m DenomTracesMigrator) IterateDenomTraces(ctx sdk.Context, cdc codec.Codec, cb func(denomTrace DenomTrace) bool) {
+
+	iterator := storetypes.KVStorePrefixIterator(m.ibcStore, ibctransfertypes.DenomTraceKey)
+
+	defer sdk.LogDeferred(ctx.Logger(), func() error { return iterator.Close() })
+	for ; iterator.Valid(); iterator.Next() {
+		denomTrace := MustUnmarshalDenomTrace(iterator.Value(), cdc)
+		if cb(denomTrace) {
+			break
+		}
+	}
+}
+
+// MustUnmarshalDenomTrace attempts to decode and return an DenomTrace object from
+// raw encoded bytes. It panics on error.
+func MustUnmarshalDenomTrace(bz []byte, cdc codec.Codec) DenomTrace {
+	var denomTrace DenomTrace
+
+	cdc.MustUnmarshal(bz, &denomTrace)
+	return denomTrace
+}
+
+// MustMarshalDenomTrace attempts to encode an DenomTrace object and returns the
+// raw encoded bytes. It panics on error.
+func MustMarshalDenomTrace(denomTrace DenomTrace, cdc codec.Codec) []byte {
+	return cdc.MustMarshal(&denomTrace)
+}
+
+// SetDenomTrace sets a new {trace hash -> denom trace} pair to the store.
+func (m DenomTracesMigrator) SetDenomTrace(ctx sdk.Context, cdc codec.Codec, denomTrace DenomTrace) {
+	bz := MustMarshalDenomTrace(denomTrace, cdc)
+	m.ibcStore.Set(denomTrace.Hash(), bz)
+}
+
+// MigrateTraces migrates the DenomTraces to the correct format, accounting for slashes in the BaseDenom.
+func (m DenomTracesMigrator) MigrateTraces(ctx sdk.Context) error {
+	ir := codectypes.NewInterfaceRegistry()
+	cdc := codec.NewProtoCodec(ir)
+
+	// list of traces that must replace the old traces in store
+	var newTraces []DenomTrace
+	m.IterateDenomTraces(ctx, cdc,
+		func(dt DenomTrace) (stop bool) {
+			// check if the new way of splitting FullDenom
+			// is the same as the current DenomTrace.
+			// If it isn't then store the new DenomTrace in the list of new traces.
+			newTrace := ParseDenomTrace(dt.GetFullDenomPath())
+			err := newTrace.Validate()
+			if err != nil {
+				panic(err)
+			}
+
+			if dt.IBCDenom() != newTrace.IBCDenom() {
+				// The new form of parsing will result in a token denomination change.
+				// A bank migration is required. A panic should occur to prevent the
+				// chain from using corrupted state.
+				panic(fmt.Errorf("migration will result in corrupted state. Previous IBC token (%s) requires a bank migration. Expected denom trace (%s)", dt, newTrace))
+			}
+
+			if !equalTraces(newTrace, dt) {
+				newTraces = append(newTraces, newTrace)
+			}
+
+			return false
+		})
+
+	// replace the outdated traces with the new trace information
+	for _, nt := range newTraces {
+		m.SetDenomTrace(ctx, cdc, nt)
+	}
+	return nil
+}