Add store package

database/store/cosmos.go

@@ -0,0 +1,97 @@
+package store
+
+import (
+	"github.com/cosmos/cosmos-sdk/types"
+)
+
+// CosmosStore is a Cosmos KVStore implementation of Store.
+type CosmosStore struct {
+	store types.KVStore
+}
+
+// NewCosmosStore returns a new Cosmos KVStore wrapper.
+func NewCosmosStore(store types.KVStore) *CosmosStore {
+	return &CosmosStore{
+		store: store,
+	}
+}
+
+// NewIterator returns a new iterator.
+func (s *CosmosStore) NewIterator() Iterator {
+	return NewCosmosIterator(types.KVStorePrefixIterator(s.store, nil))
+}
+
+// Has returns true if the key is set in the store.
+func (s *CosmosStore) Has(key []byte) (bool, error) {
+	return s.store.Has(key), nil
+}
+
+// Get retrives service from store. It returns ErrNotFound if the store does not contains the key.
+func (s *CosmosStore) Get(key []byte) ([]byte, error) {
+	has, err := s.Has(key)
+	if err != nil {
+		return nil, err
+	}
+	if !has {
+		return nil, ErrNotFound
+	}
+	return s.store.Get(key), nil
+}
+
+// Delete deletes the value for the given key. Delete will not returns error if key doesn't exist.
+func (s *CosmosStore) Delete(key []byte) error {
+	s.store.Delete(key)
+	return nil
+}
+
+// Put sets the value for the given key. It overwrites any previous value.
+func (s *CosmosStore) Put(key []byte, value []byte) error {
+	s.store.Set(key, value)
+	return nil
+}
+
+// Close closes the store.
+func (s *CosmosStore) Close() error {
+	return nil
+}
+
+// CosmosIterator is a Cosmos KVStore's iterator implementation of Iterator.
+type CosmosIterator struct {
+	iter types.Iterator
+}
+
+// NewCosmosIterator returns a new Cosmos KVStore Iterator wrapper.
+func NewCosmosIterator(iter types.Iterator) *CosmosIterator {
+	return &CosmosIterator{
+		iter: iter,
+	}
+}
+
+// Next moves the iterator to the next sequential key in the store.
+func (i *CosmosIterator) Next() bool {
+	if i.iter.Valid() {
+		i.iter.Next()
+		return true
+	}
+	return false
+}
+
+// Key returns the key of the cursor.
+func (i *CosmosIterator) Key() []byte {
+	return i.iter.Key()
+}
+
+// Value returns the value of the cursor.
+func (i *CosmosIterator) Value() []byte {
+	return i.iter.Value()
+}
+
+// Release releases the Iterator.
+func (i *CosmosIterator) Release() {
+	i.iter.Close()
+}
+
+// Error returns any accumulated error.
+func (i *CosmosIterator) Error() error {
+	return nil
+}

database/store/interface.go

@@ -0,0 +1,45 @@
+package store
+
+import "errors"
+
+// Store describes the public API of a store.
+type Store interface {
+	// Get retrives service from store. It returns ErrNotFound if the store does not contains the key.
+	Get(key []byte) ([]byte, error)
+
+	// Has returns true if the key is set in the store.
+	Has(key []byte) (bool, error)
+
+	// Delete deletes the value for the given key. Delete will not returns error if key doesn't exist.
+	Delete(key []byte) error
+
+	// Put sets the value for the given key. It overwrites any previous value.
+	Put(key []byte, value []byte) error
+
+	// NewIterator returns a new iterator.
+	NewIterator() Iterator
+
+	// Close closes the store.
+	Close() error
+}
+
+// Iterator describes the public API of an iterator.
+type Iterator interface {
+	// Next moves the iterator to the next sequential key in the store.
+	Next() bool
+
+	// Key returns the key of the cursor.
+	Key() []byte
+
+	// Value returns the value of the cursor.
+	Value() []byte
+
+	// Release releases the Iterator.
+	Release()
+
+	// Error returns any accumulated error.
+	Error() error
+}
+
+// ErrNotFound is throw when getting a non-existing key.
+var ErrNotFound = errors.New("store: not found")

database/store/leveldb.go

@@ -0,0 +1,59 @@
+package store
+
+import (
+	"github.com/syndtr/goleveldb/leveldb"
+)
+
+// LevelDBStore is a levelDB implementation of Store.
+type LevelDBStore struct {
+	db *leveldb.DB
+}
+
+// NewLevelDBStore returns a new level db wrapper.
+func NewLevelDBStore(path string) (*LevelDBStore, error) {
+	db, err := leveldb.OpenFile(path, nil)
+	if err != nil {
+		return nil, err
+	}
+	return &LevelDBStore{
+		db: db,
+	}, nil
+}
+
+// NewIterator returns a new iterator.
+func (s *LevelDBStore) NewIterator() Iterator {
+	return s.db.NewIterator(nil, nil)
+}
+
+// Has returns true if the key is set in the store.
+func (s *LevelDBStore) Has(key []byte) (bool, error) {
+	_, err := s.Get(key)
+	return err != ErrNotFound, err
+}
+
+// Get retrives service from store. It returns ErrNotFound if the store does not contains the key.
+func (s *LevelDBStore) Get(key []byte) ([]byte, error) {
+	value, err := s.db.Get(key, nil)
+	if err == leveldb.ErrNotFound {
+		return nil, ErrNotFound
+	}
+	if err != nil {
+		return nil, err
+	}
+	return value, nil
+}
+
+// Delete deletes the value for the given key. Delete will not returns error if key doesn't exist.
+func (s *LevelDBStore) Delete(key []byte) error {
+	return s.db.Delete(key, nil)
+}
+
+// Put sets the value for the given key. It overwrites any previous value.
+func (s *LevelDBStore) Put(key []byte, value []byte) error {
+	return s.db.Put(key, value, nil)
+}
+
+// Close closes the store.
+func (s *LevelDBStore) Close() error {
+	return s.db.Close()
+}