cosmos-sdk/collections/map.go
2025-05-13 16:46:47 +00:00

299 lines
8.3 KiB
Go

package collections
import (
"bytes"
"context"
"fmt"
"cosmossdk.io/collections/codec"
store "cosmossdk.io/collections/corecompat"
)
// Map represents the basic collections object.
// It is used to map arbitrary keys to arbitrary
// objects.
type Map[K, V any] struct {
kc codec.KeyCodec[K]
vc codec.ValueCodec[V]
// store accessor
sa func(context.Context) store.KVStore
prefix []byte
name string
// isSecondaryIndex indicates that this map represents a secondary index
// on another collection and that it should be skipped when generating
// a user facing schema
isSecondaryIndex bool
}
// withMapSecondaryIndex changes the behavior of the Map to be a secondary index.
func withMapSecondaryIndex(isSecondaryIndex bool) func(opt *mapOptions) {
return func(opt *mapOptions) {
opt.isSecondaryIndex = isSecondaryIndex
}
}
type mapOptions struct {
isSecondaryIndex bool
}
// NewMap returns a Map given a StoreKey, a Prefix, human-readable name and the relative value and key encoders.
// Name and prefix must be unique within the schema and name must match the format specified by NameRegex, or
// else this method will panic.
func NewMap[K, V any](
schemaBuilder *SchemaBuilder,
prefix Prefix,
name string,
keyCodec codec.KeyCodec[K],
valueCodec codec.ValueCodec[V],
options ...func(opt *mapOptions),
) Map[K, V] {
o := new(mapOptions)
for _, opt := range options {
opt(o)
}
m := Map[K, V]{
kc: keyCodec,
vc: valueCodec,
sa: schemaBuilder.schema.storeAccessor,
prefix: prefix.Bytes(),
name: name,
isSecondaryIndex: o.isSecondaryIndex,
}
schemaBuilder.addCollection(collectionImpl[K, V]{m})
return m
}
func (m Map[K, V]) GetName() string {
return m.name
}
func (m Map[K, V]) GetPrefix() []byte {
return m.prefix
}
// Set maps the provided value to the provided key in the store.
// Errors with ErrEncoding if key or value encoding fails.
func (m Map[K, V]) Set(ctx context.Context, key K, value V) error {
bytesKey, err := EncodeKeyWithPrefix(m.prefix, m.kc, key)
if err != nil {
return err
}
valueBytes, err := m.vc.Encode(value)
if err != nil {
return fmt.Errorf("%w: value encode: %w", ErrEncoding, err)
}
kvStore := m.sa(ctx)
return kvStore.Set(bytesKey, valueBytes)
}
// Get returns the value associated with the provided key,
// errors with ErrNotFound if the key does not exist, or
// with ErrEncoding if the key or value decoding fails.
func (m Map[K, V]) Get(ctx context.Context, key K) (v V, err error) {
bytesKey, err := EncodeKeyWithPrefix(m.prefix, m.kc, key)
if err != nil {
return v, err
}
kvStore := m.sa(ctx)
valueBytes, err := kvStore.Get(bytesKey)
if err != nil {
return v, err
}
if valueBytes == nil {
return v, fmt.Errorf("%w: key '%s' of type %s", ErrNotFound, m.kc.Stringify(key), m.vc.ValueType())
}
v, err = m.vc.Decode(valueBytes)
if err != nil {
return v, fmt.Errorf("%w: value decode: %w", ErrEncoding, err)
}
return v, nil
}
// Has reports whether the key is present in storage or not.
// Errors with ErrEncoding if key encoding fails.
func (m Map[K, V]) Has(ctx context.Context, key K) (bool, error) {
bytesKey, err := EncodeKeyWithPrefix(m.prefix, m.kc, key)
if err != nil {
return false, err
}
kvStore := m.sa(ctx)
return kvStore.Has(bytesKey)
}
// Remove removes the key from the storage.
// Errors with ErrEncoding if key encoding fails.
// If the key does not exist then this is a no-op.
func (m Map[K, V]) Remove(ctx context.Context, key K) error {
bytesKey, err := EncodeKeyWithPrefix(m.prefix, m.kc, key)
if err != nil {
return err
}
kvStore := m.sa(ctx)
return kvStore.Delete(bytesKey)
}
// Iterate provides an Iterator over K and V. It accepts a Ranger interface.
// A nil ranger equals to iterate over all the keys in ascending order.
func (m Map[K, V]) Iterate(ctx context.Context, ranger Ranger[K]) (Iterator[K, V], error) {
return iteratorFromRanger(ctx, m, ranger)
}
// Walk iterates over the Map with the provided range, calls the provided
// walk function with the decoded key and value. If the callback function
// returns true then the walking is stopped.
// A nil ranger equals to walking over the entire key and value set.
func (m Map[K, V]) Walk(ctx context.Context, ranger Ranger[K], walkFunc func(key K, value V) (stop bool, err error)) error {
iter, err := m.Iterate(ctx, ranger)
if err != nil {
return err
}
defer iter.Close()
for ; iter.Valid(); iter.Next() {
kv, err := iter.KeyValue()
if err != nil {
return err
}
stop, err := walkFunc(kv.Key, kv.Value)
if err != nil {
return err
}
if stop {
return nil
}
}
return nil
}
// Clear clears the collection contained within the provided key range.
// A nil ranger equals to clearing the whole collection.
// NOTE: this API needs to be used with care, considering that as of today
// cosmos-sdk stores the deletion records to be committed in a memory cache,
// clearing a lot of data might make the node go OOM.
func (m Map[K, V]) Clear(ctx context.Context, ranger Ranger[K]) error {
startBytes, endBytes, _, err := parseRangeInstruction(m.prefix, m.kc, ranger)
if err != nil {
return err
}
return deleteDomain(m.sa(ctx), startBytes, endBytes)
}
const clearBatchSize = 10000
// deleteDomain deletes the domain of an iterator, the key difference
// is that it uses batches to clear the store meaning that it will read
// the keys within the domain close the iterator and then delete them.
func deleteDomain(s store.KVStore, start, end []byte) error {
for {
iter, err := s.Iterator(start, end)
if err != nil {
return err
}
keys := make([][]byte, 0, clearBatchSize)
for ; iter.Valid() && len(keys) < clearBatchSize; iter.Next() {
keys = append(keys, iter.Key())
}
// we close the iterator here instead of deferring
err = iter.Close()
if err != nil {
return err
}
for _, key := range keys {
err = s.Delete(key)
if err != nil {
return err
}
}
// If we've retrieved less than the batchSize, we're done.
if len(keys) < clearBatchSize {
break
}
}
return nil
}
// concatNew concatenates two byte slices, prefix and suffix, into a new byte slice and returns the result.
func concatNew(prefix, suffix []byte) []byte {
b := make([]byte, len(prefix)+len(suffix))
copy(b, prefix)
copy(b[len(prefix):], suffix)
return b
}
// IterateRaw iterates over the collection. The iteration range is untyped, it uses raw
// bytes. The resulting Iterator is typed.
// A nil start iterates from the first key contained in the collection.
// A nil end iterates up to the last key contained in the collection.
// A nil start and a nil end iterates over every key contained in the collection.
// TODO(tip): simplify after https://github.com/cosmos/cosmos-sdk/pull/14310 is merged
func (m Map[K, V]) IterateRaw(ctx context.Context, start, end []byte, order Order) (Iterator[K, V], error) {
prefixedStart := concatNew(m.prefix, start)
var prefixedEnd []byte
if end == nil {
prefixedEnd = nextBytesPrefixKey(m.prefix)
} else {
prefixedEnd = concatNew(m.prefix, end)
}
if bytes.Compare(prefixedStart, prefixedEnd) == 1 {
return Iterator[K, V]{}, ErrInvalidIterator
}
s := m.sa(ctx)
var (
storeIter store.Iterator
err error
)
switch order {
case OrderAscending:
storeIter, err = s.Iterator(prefixedStart, prefixedEnd)
case OrderDescending:
storeIter, err = s.ReverseIterator(prefixedStart, prefixedEnd)
default:
return Iterator[K, V]{}, errOrder
}
if err != nil {
return Iterator[K, V]{}, err
}
return Iterator[K, V]{
kc: m.kc,
vc: m.vc,
iter: storeIter,
prefixLength: len(m.prefix),
}, nil
}
// KeyCodec returns the Map's KeyCodec.
func (m Map[K, V]) KeyCodec() codec.KeyCodec[K] { return m.kc }
// ValueCodec returns the Map's ValueCodec.
func (m Map[K, V]) ValueCodec() codec.ValueCodec[V] { return m.vc }
// EncodeKeyWithPrefix returns how the collection would store the key in storage given
// prefix, key codec and the concrete key.
func EncodeKeyWithPrefix[K any](prefix []byte, kc codec.KeyCodec[K], key K) ([]byte, error) {
prefixLen := len(prefix)
// preallocate buffer
keyBytes := make([]byte, prefixLen+kc.Size(key))
// put prefix
copy(keyBytes, prefix)
// put key
_, err := kc.Encode(keyBytes[prefixLen:], key)
if err != nil {
return nil, fmt.Errorf("%w: key encode: %w", ErrEncoding, err)
}
return keyBytes, nil
}