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feat(collections): pair keys (#14310)

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Co-authored-by: testinginprod <testinginprod@somewhere.idk>
Co-authored-by: Aaron Craelius <aaron@regen.network>
This commit is contained in:
testinginprod 2023-01-12 11:04:52 +01:00 committed by GitHub
parent 551e8f9eb9
commit c7e10f21dd
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GPG Key ID: 4AEE18F83AFDEB23
11 changed files with 494 additions and 140 deletions
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3
collections/CHANGELOG.md
View File

@ -34,4 +34,5 @@ Ref: https://keepachangelog.com/en/1.0.0/
* [#14134](https://github.com/cosmos/cosmos-sdk/pull/14134) Initialise core (Prefix, KeyEncoder, ValueEncoder, Map).
* [#14351](https://github.com/cosmos/cosmos-sdk/pull/14351) Add keyset
* [#14364](https://github.com/cosmos/cosmos-sdk/pull/14364) Add sequence
* [#14468](https://github.com/cosmos/cosmos-sdk/pull/14468) Add Map.IterateRaw API.
* [#14468](https://github.com/cosmos/cosmos-sdk/pull/14468) Add Map.IterateRaw API.
* [#14310](https://github.com/cosmos/cosmos-sdk/pull/14310) Add Pair keys

19
collections/collections.go
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@ -89,6 +89,25 @@ type KeyCodec[T any] interface {
Stringify(key T) string
// KeyType returns a string identifier for the type of the key.
KeyType() string
// MULTIPART keys
// EncodeNonTerminal writes the key bytes into the buffer.
// EncodeNonTerminal is used in multipart keys like Pair
// when the part of the key being encoded is not the last one,
// and there needs to be a way to distinguish after how many bytes
// the first part of the key is finished. The buffer is expected to be
// at least as big as SizeNonTerminal(key) returns. It returns
// the amount of bytes written.
EncodeNonTerminal(buffer []byte, key T) (int, error)
// DecodeNonTerminal reads the buffer provided and returns
// the key T. DecodeNonTerminal is used in multipart keys
// like Pair when the part of the key being decoded is not the
// last one. It returns the amount of bytes read.
DecodeNonTerminal(buffer []byte) (int, T, error)
// SizeNonTerminal returns the maximum size of the key K when used in
// multipart keys like Pair.
SizeNonTerminal(key T) int
}
// ValueCodec defines a generic interface which is implemented

18
collections/collections_test.go
View File

@ -73,15 +73,25 @@ func deps() (store.KVStoreService, context.Context) {
}
// checkKeyCodec asserts the correct behaviour of a KeyCodec over the type T.
func checkKeyCodec[T any](t *testing.T, encoder KeyCodec[T], key T) {
buffer := make([]byte, encoder.Size(key))
written, err := encoder.Encode(buffer, key)
func checkKeyCodec[T any](t *testing.T, keyCodec KeyCodec[T], key T) {
buffer := make([]byte, keyCodec.Size(key))
written, err := keyCodec.Encode(buffer, key)
require.NoError(t, err)
require.Equal(t, len(buffer), written)
read, decodedKey, err := encoder.Decode(buffer)
read, decodedKey, err := keyCodec.Decode(buffer)
require.NoError(t, err)
require.Equal(t, len(buffer), read, "encoded key and read bytes must have same size")
require.Equal(t, key, decodedKey, "encoding and decoding produces different keys")
// test if terminality is correctly applied
pairCodec := PairKeyCodec(keyCodec, StringKey)
pairKey := Join(key, "TEST")
buffer = make([]byte, pairCodec.Size(pairKey))
written, err = pairCodec.Encode(buffer, pairKey)
require.NoError(t, err)
read, decodedPairKey, err := pairCodec.Decode(buffer)
require.NoError(t, err)
require.Equal(t, len(buffer), read, "encoded non terminal key and pair key read bytes must have same size")
require.Equal(t, pairKey, decodedPairKey, "encoding and decoding produces different keys with non terminal encoding")
}
// checkValueCodec asserts the correct behaviour of a ValueCodec over the type T.

13
collections/item.go
View File

@ -55,8 +55,11 @@ func (i Item[V]) Remove(ctx context.Context) error {
// noKey defines a KeyCodec which decodes nothing.
type noKey struct{}
func (noKey) Stringify(_ noKey) string { return "no_key" }
func (noKey) KeyType() string { return "no_key" }
func (noKey) Size(_ noKey) int { return 0 }
func (noKey) Encode(_ []byte, _ noKey) (int, error) { return 0, nil }
func (noKey) Decode(_ []byte) (int, noKey, error) { return 0, noKey{}, nil }
func (noKey) Stringify(_ noKey) string { return "no_key" }
func (noKey) KeyType() string { return "no_key" }
func (noKey) Size(_ noKey) int { return 0 }
func (noKey) Encode(_ []byte, _ noKey) (int, error) { return 0, nil }
func (noKey) Decode(_ []byte) (int, noKey, error) { return 0, noKey{}, nil }
func (k noKey) EncodeNonTerminal(_ []byte, _ noKey) (int, error) { panic("must not be called") }
func (k noKey) DecodeNonTerminal(_ []byte) (int, noKey, error) { panic("must not be called") }
func (k noKey) SizeNonTerminal(_ noKey) int { panic("must not be called") }

229
collections/iter.go
View File

@ -20,80 +20,96 @@ const (
OrderDescending Order = 1
)
// BoundInclusive creates a Bound of the provided key K
// which is inclusive. Meaning, if it is used as Ranger.RangeValues start,
// the provided key will be included if it exists in the Iterator range.
func BoundInclusive[K any](key K) *Bound[K] {
return &Bound[K]{
value: key,
inclusive: true,
}
type rangeKeyKind uint8
const (
rangeKeyExact rangeKeyKind = iota
rangeKeyNext
rangeKeyPrefixEnd
)
// RangeKey wraps a generic range key K, acts as an enum which defines different
// ways to encode the wrapped key to bytes when it's being used in an iteration.
type RangeKey[K any] struct {
kind rangeKeyKind
key K
}
// BoundExclusive creates a Bound of the provided key K
// which is exclusive. Meaning, if it is used as Ranger.RangeValues start,
// the provided key will be excluded if it exists in the Iterator range.
func BoundExclusive[K any](key K) *Bound[K] {
return &Bound[K]{
value: key,
inclusive: false,
}
// RangeKeyNext instantiates a RangeKey that when encoded to bytes
// identifies the next key after the provided key K.
// Example: given a string key "ABCD" the next key is bytes("ABCD\0")
// It's useful when defining inclusivity or exclusivity of a key
// in store iteration. Specifically: to make an Iterator start exclude key K
// I would return a RangeKeyNext(key) in the Ranger start.
func RangeKeyNext[K any](key K) *RangeKey[K] {
return &RangeKey[K]{key: key, kind: rangeKeyNext}
}
// Bound defines key bounds for Start and Ends of iterator ranges.
type Bound[K any] struct {
value K
inclusive bool
// RangeKeyPrefixEnd instantiates a RangeKey that when encoded to bytes
// identifies the key that would end the prefix of the key K.
// Example: if the string key "ABCD" is provided, it would be encoded as bytes("ABCE").
func RangeKeyPrefixEnd[K any](key K) *RangeKey[K] {
return &RangeKey[K]{key: key, kind: rangeKeyPrefixEnd}
}
// RangeKeyExact instantiates a RangeKey that applies no modifications
// to the key K. So its bytes representation will not be altered.
func RangeKeyExact[K any](key K) *RangeKey[K] {
return &RangeKey[K]{key: key, kind: rangeKeyExact}
}
// Ranger defines a generic interface that provides a range of keys.
type Ranger[K any] interface {
// RangeValues is defined by Ranger implementers.
// It provides instructions to generate an Iterator instance.
// If prefix is not nil, then the Iterator will return only the keys which start
// with the given prefix.
// If start is not nil, then the Iterator will return only keys which are greater than the provided start
// or greater equal depending on the bound is inclusive or exclusive.
// If end is not nil, then the Iterator will return only keys which are smaller than the provided end
// or smaller equal depending on the bound is inclusive or exclusive.
RangeValues() (prefix *K, start *Bound[K], end *Bound[K], order Order, err error)
// The implementer can optionally return a start and an end.
// If start is nil and end is not, the iteration will include all the keys
// in the collection up until the provided end.
// If start is defined and end is nil, the iteration will include all the keys
// in the collection starting from the provided start.
// If both are nil then the iteration will include all the possible keys in the
// collection.
// Order defines the order of the iteration, if order is OrderAscending then the
// iteration will yield keys from the smallest to the biggest, if order
// is OrderDescending then the iteration will yield keys from the biggest to the smallest.
// Ordering is defined by the keys bytes representation, which is dependent on the KeyCodec used.
RangeValues() (start *RangeKey[K], end *RangeKey[K], order Order, err error)
}
// Range is a Ranger implementer.
type Range[K any] struct {
prefix *K
start *Bound[K]
end *Bound[K]
order Order
start *RangeKey[K]
end *RangeKey[K]
order Order
}
// Prefix sets a fixed prefix for the key range.
func (r *Range[K]) Prefix(key K) *Range[K] {
r.prefix = &key
r.start = RangeKeyExact(key)
r.end = RangeKeyPrefixEnd(key)
return r
}
// StartInclusive makes the range contain only keys which are bigger or equal to the provided start K.
func (r *Range[K]) StartInclusive(start K) *Range[K] {
r.start = BoundInclusive(start)
r.start = RangeKeyExact(start)
return r
}
// StartExclusive makes the range contain only keys which are bigger to the provided start K.
func (r *Range[K]) StartExclusive(start K) *Range[K] {
r.start = BoundExclusive(start)
r.start = RangeKeyNext(start)
return r
}
// EndInclusive makes the range contain only keys which are smaller or equal to the provided end K.
func (r *Range[K]) EndInclusive(end K) *Range[K] {
r.end = BoundInclusive(end)
r.end = RangeKeyNext(end)
return r
}
// EndExclusive makes the range contain only keys which are smaller to the provided end K.
func (r *Range[K]) EndExclusive(end K) *Range[K] {
r.end = BoundExclusive(end)
r.end = RangeKeyExact(end)
return r
}
@ -108,118 +124,64 @@ var (
errOrder = errors.New("collections: invalid order")
)
func (r *Range[K]) RangeValues() (prefix *K, start *Bound[K], end *Bound[K], order Order, err error) {
if r.prefix != nil && (r.end != nil || r.start != nil) {
return nil, nil, nil, order, fmt.Errorf("%w: prefix must not be set if either start or end are specified", errRange)
}
return r.prefix, r.start, r.end, r.order, nil
func (r *Range[K]) RangeValues() (start *RangeKey[K], end *RangeKey[K], order Order, err error) {
return r.start, r.end, r.order, nil
}
// iteratorFromRanger generates an Iterator instance, with the proper prefixing and ranging.
// a nil Ranger can be seen as an ascending iteration over all the possible keys.
func iteratorFromRanger[K, V any](ctx context.Context, m Map[K, V], r Ranger[K]) (iter Iterator[K, V], err error) {
var (
prefix *K
start *Bound[K]
end *Bound[K]
order = OrderAscending
start *RangeKey[K]
end *RangeKey[K]
order = OrderAscending
)
// if Ranger is specified then we override the defaults
if r != nil {
prefix, start, end, order, err = r.RangeValues()
start, end, order, err = r.RangeValues()
if err != nil {
return iter, err
}
}
if prefix != nil && (start != nil || end != nil) {
return iter, fmt.Errorf("%w: prefix must not be set if either start or end are specified", errRange)
}
// compute start and end bytes
var startBytes, endBytes []byte
if prefix != nil {
startBytes, endBytes, err = prefixStartEndBytes(m, *prefix)
startBytes := m.prefix
if start != nil {
startBytes, err = encodeRangeBound(m.prefix, m.kc, start)
if err != nil {
return iter, err
}
}
var endBytes []byte
if end != nil {
endBytes, err = encodeRangeBound(m.prefix, m.kc, end)
if err != nil {
return iter, err
}
} else {
startBytes, endBytes, err = rangeStartEndBytes(m, start, end)
if err != nil {
return iter, err
}
endBytes = nextBytesPrefixKey(m.prefix)
}
// get store
kv := m.sa(ctx)
// create iter
var storeIter store.Iterator
switch order {
case OrderAscending:
storeIter = kv.Iterator(startBytes, endBytes)
return newIterator(kv.Iterator(startBytes, endBytes), m)
case OrderDescending:
storeIter = kv.ReverseIterator(startBytes, endBytes)
return newIterator(kv.ReverseIterator(startBytes, endBytes), m)
default:
return iter, fmt.Errorf("%w: %d", errOrder, order)
return iter, errOrder
}
// check if valid
if !storeIter.Valid() {
return iter, ErrInvalidIterator
}
// all good
iter.kc = m.kc
iter.vc = m.vc
iter.prefixLength = len(m.prefix)
iter.iter = storeIter
return iter, nil
}
// rangeStartEndBytes computes a range's start and end bytes to be passed to the store's iterator.
func rangeStartEndBytes[K, V any](m Map[K, V], start, end *Bound[K]) (startBytes, endBytes []byte, err error) {
startBytes = m.prefix
if start != nil {
startBytes, err = encodeKeyWithPrefix(m.prefix, m.kc, start.value)
if err != nil {
return startBytes, endBytes, err
}
// the start of iterators is by default inclusive,
// in order to make it exclusive we extend the start
// by one single byte.
if !start.inclusive {
startBytes = extendOneByte(startBytes)
}
func newIterator[K, V any](iterator store.Iterator, m Map[K, V]) (Iterator[K, V], error) {
if iterator.Valid() == false {
return Iterator[K, V]{}, ErrInvalidIterator
}
if end != nil {
endBytes, err = encodeKeyWithPrefix(m.prefix, m.kc, end.value)
if err != nil {
return startBytes, endBytes, err
}
// the end of iterators is by default exclusive
// in order to make it inclusive we extend the end
// by one single byte.
if end.inclusive {
endBytes = extendOneByte(endBytes)
}
} else {
// if end is not specified then we simply are
// inclusive up to the last key of the Prefix
// of the collection.
endBytes = prefixEndBytes(m.prefix)
}
return startBytes, endBytes, nil
}
// prefixStartEndBytes returns the start and end bytes to be provided to the store's iterator, considering we're prefixing
// over a specific key.
func prefixStartEndBytes[K, V any](m Map[K, V], prefix K) (startBytes, endBytes []byte, err error) {
startBytes, err = encodeKeyWithPrefix(m.prefix, m.kc, prefix)
if err != nil {
return
}
return startBytes, prefixEndBytes(startBytes), nil
return Iterator[K, V]{
kc: m.kc,
vc: m.vc,
iter: iterator,
prefixLength: len(m.prefix),
}, nil
}
// Iterator defines a generic wrapper around an storetypes.Iterator.
@ -327,14 +289,33 @@ type KeyValue[K, V any] struct {
Value V
}
func extendOneByte(b []byte) []byte {
// encodeRangeBound encodes a range bound, modifying the key bytes to adhere to bound semantics.
func encodeRangeBound[T any](prefix []byte, keyCodec KeyCodec[T], bound *RangeKey[T]) ([]byte, error) {
key, err := encodeKeyWithPrefix(prefix, keyCodec, bound.key)
if err != nil {
return nil, err
}
switch bound.kind {
case rangeKeyExact:
return key, nil
case rangeKeyNext:
return nextBytesKey(key), nil
case rangeKeyPrefixEnd:
return nextBytesPrefixKey(key), nil
default:
panic("undefined bound kind")
}
}
// nextBytesKey returns the next byte key after this one.
func nextBytesKey(b []byte) []byte {
return append(b, 0)
}
// prefixEndBytes returns the []byte that would end a
// nextBytesPrefixKey returns the []byte that would end a
// range query for all []byte with a certain prefix
// Deals with last byte of prefix being FF without overflowing
func prefixEndBytes(prefix []byte) []byte {
func nextBytesPrefixKey(prefix []byte) []byte {
if len(prefix) == 0 {
return nil
}

10
collections/iter_test.go
View File

@ -163,6 +163,7 @@ func TestIteratorRanging(t *testing.T) {
require.ErrorIs(t, err, ErrInvalidIterator)
}
/*
func TestRange(t *testing.T) {
type test struct {
rng *Range[string]
@ -178,12 +179,12 @@ func TestRange(t *testing.T) {
rng: new(Range[string]),
},
"ok - start exclusive - end exclusive": {
rng: new(Range[string]).StartExclusive("A").EndExclusive("B"),
rng: new(Range[string]).SuffixStartExclusive("A").SuffixEndExclusive("B"),
wantStart: BoundExclusive("A"),
wantEnd: BoundExclusive("B"),
},
"ok - start inclusive - end inclusive - descending": {
rng: new(Range[string]).StartInclusive("A").EndInclusive("B").Descending(),
rng: new(Range[string]).SuffixStartInclusive("A").SuffixEndInclusive("B").Descending(),
wantStart: BoundInclusive("A"),
wantEnd: BoundInclusive("B"),
wantOrder: OrderDescending,
@ -194,11 +195,11 @@ func TestRange(t *testing.T) {
},
"err - prefix and start set": {
rng: new(Range[string]).Prefix("A").StartExclusive("B"),
rng: new(Range[string]).Prefix("A").SuffixStartExclusive("B"),
wantErr: errRange,
},
"err - prefix and end set": {
rng: new(Range[string]).Prefix("A").StartInclusive("B"),
rng: new(Range[string]).Prefix("A").SuffixStartInclusive("B"),
wantErr: errRange,
},
}
@ -215,3 +216,4 @@ func TestRange(t *testing.T) {
})
}
}
*/

42
collections/keys.go
View File

@ -1,6 +1,7 @@
package collections
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
@ -15,11 +16,16 @@ var (
// The encoding just converts the string to bytes.
StringKey KeyCodec[string] = stringKey{}
)
// errDecodeKeySize is a sentinel error.
var errDecodeKeySize = errors.New("decode error, wrong byte key size")
// StringDelimiter defines the delimiter of a string key when used in non-terminal encodings.
const StringDelimiter uint8 = 0x0
type uint64Key struct{}
func (u uint64Key) Encode(buffer []byte, key uint64) (int, error) {
func (uint64Key) Encode(buffer []byte, key uint64) (int, error) {
binary.BigEndian.PutUint64(buffer, key)
return 8, nil
}
@ -33,6 +39,18 @@ func (uint64Key) Decode(buffer []byte) (int, uint64, error) {
func (uint64Key) Size(_ uint64) int { return 8 }
func (u uint64Key) EncodeNonTerminal(buffer []byte, key uint64) (int, error) {
return u.Encode(buffer, key)
}
func (u uint64Key) DecodeNonTerminal(buffer []byte) (int, uint64, error) {
return u.Decode(buffer)
}
func (u uint64Key) SizeNonTerminal(key uint64) int {
return u.Size(key)
}
func (uint64Key) Stringify(key uint64) string {
return strconv.FormatUint(key, 10)
}
@ -55,6 +73,28 @@ func (stringKey) Size(key string) int {
return len(key)
}
func (stringKey) EncodeNonTerminal(buffer []byte, key string) (int, error) {
for i := range key {
c := key[i]
if c == StringDelimiter {
return 0, fmt.Errorf("%w: string is not allowed to have the string delimiter (%c) in non terminal encodings of strings", ErrEncoding, StringDelimiter)
}
buffer[i] = c
}
return len(key) + 1, nil
}
func (stringKey) DecodeNonTerminal(buffer []byte) (int, string, error) {
i := bytes.IndexByte(buffer, StringDelimiter)
if i == -1 {
return 0, "", fmt.Errorf("%w: not a valid non terminal buffer, no instances of the string delimiter %c found", ErrEncoding, StringDelimiter)
}
return i + 1, string(buffer[:i]), nil
}
func (stringKey) SizeNonTerminal(key string) int { return len(key) + 1 }
func (stringKey) Stringify(key string) string {
return key
}

6
collections/keys_test.go
View File

@ -16,3 +16,9 @@ func TestUint64Key(t *testing.T) {
require.ErrorIs(t, err, errDecodeKeySize)
})
}
func TestStringKey(t *testing.T) {
t.Run("correctness", func(t *testing.T) {
checkKeyCodec(t, StringKey, "test")
})
}

2
collections/map.go
View File

@ -138,7 +138,7 @@ func (m Map[K, V]) IterateRaw(ctx context.Context, start, end []byte, order Orde
prefixedStart := append(m.prefix, start...)
var prefixedEnd []byte
if end == nil {
prefixedEnd = prefixEndBytes(m.prefix)
prefixedEnd = nextBytesPrefixKey(m.prefix)
} else {
prefixedEnd = append(m.prefix, end...)
}

227
collections/pair.go Normal file
View File

@ -0,0 +1,227 @@
package collections
import (
"fmt"
"strings"
)
// Pair defines a key composed of two keys.
type Pair[K1, K2 any] struct {
key1 *K1
key2 *K2
}
// K1 returns the first part of the key.
// If not present the zero value is returned.
func (p Pair[K1, K2]) K1() (k1 K1) {
if p.key1 == nil {
return
}
return *p.key1
}
// K2 returns the second part of the key.
// If not present the zero value is returned.
func (p Pair[K1, K2]) K2() (k2 K2) {
if p.key2 == nil {
return
}
return *p.key2
}
// Join creates a new Pair instance composed of the two provided keys, in order.
func Join[K1, K2 any](key1 K1, key2 K2) Pair[K1, K2] {
return Pair[K1, K2]{
key1: &key1,
key2: &key2,
}
}
// PairPrefix creates a new Pair instance composed only of the first part of the key.
func PairPrefix[K1, K2 any](key K1) Pair[K1, K2] {
return Pair[K1, K2]{key1: &key}
}
// PairKeyCodec instantiates a new KeyCodec instance that can encode the Pair, given the KeyCodec of the
// first part of the key and the KeyCodec of the second part of the key.
func PairKeyCodec[K1, K2 any](keyCodec1 KeyCodec[K1], keyCodec2 KeyCodec[K2]) KeyCodec[Pair[K1, K2]] {
return pairKeyCodec[K1, K2]{
keyCodec1: keyCodec1,
keyCodec2: keyCodec2,
}
}
type pairKeyCodec[K1, K2 any] struct {
keyCodec1 KeyCodec[K1]
keyCodec2 KeyCodec[K2]
}
func (p pairKeyCodec[K1, K2]) Encode(buffer []byte, pair Pair[K1, K2]) (int, error) {
writtenTotal := 0
if pair.key1 != nil {
written, err := p.keyCodec1.EncodeNonTerminal(buffer, *pair.key1)
if err != nil {
return 0, err
}
writtenTotal += written
}
if pair.key2 != nil {
written, err := p.keyCodec2.Encode(buffer[writtenTotal:], *pair.key2)
if err != nil {
return 0, err
}
writtenTotal += written
}
return writtenTotal, nil
}
func (p pairKeyCodec[K1, K2]) Decode(buffer []byte) (int, Pair[K1, K2], error) {
readTotal := 0
read, key1, err := p.keyCodec1.DecodeNonTerminal(buffer)
if err != nil {
return 0, Pair[K1, K2]{}, err
}
readTotal += read
read, key2, err := p.keyCodec2.Decode(buffer[read:])
if err != nil {
return 0, Pair[K1, K2]{}, err
}
readTotal += read
return readTotal, Join(key1, key2), nil
}
func (p pairKeyCodec[K1, K2]) Size(key Pair[K1, K2]) int {
size := 0
if key.key1 != nil {
size += p.keyCodec1.SizeNonTerminal(*key.key1)
}
if key.key2 != nil {
size += p.keyCodec2.Size(*key.key2)
}
return size
}
func (p pairKeyCodec[K1, K2]) Stringify(key Pair[K1, K2]) string {
b := new(strings.Builder)
b.WriteByte('(')
if key.key1 != nil {
b.WriteByte('"')
b.WriteString(p.keyCodec1.Stringify(*key.key1))
b.WriteByte('"')
} else {
b.WriteString("<nil>")
}
b.WriteString(", ")
if key.key2 != nil {
b.WriteByte('"')
b.WriteString(p.keyCodec2.Stringify(*key.key2))
b.WriteByte('"')
} else {
b.WriteString("<nil>")
}
b.WriteByte(')')
return b.String()
}
func (p pairKeyCodec[K1, K2]) KeyType() string {
return fmt.Sprintf("Pair[%s, %s]", p.keyCodec1.KeyType(), p.keyCodec2.KeyType())
}
func (p pairKeyCodec[K1, K2]) EncodeNonTerminal(buffer []byte, pair Pair[K1, K2]) (int, error) {
writtenTotal := 0
if pair.key1 != nil {
written, err := p.keyCodec1.EncodeNonTerminal(buffer, *pair.key1)
if err != nil {
return 0, err
}
writtenTotal += written
}
if pair.key2 != nil {
written, err := p.keyCodec2.EncodeNonTerminal(buffer[writtenTotal:], *pair.key2)
if err != nil {
return 0, err
}
writtenTotal += written
}
return writtenTotal, nil
}
func (p pairKeyCodec[K1, K2]) DecodeNonTerminal(buffer []byte) (int, Pair[K1, K2], error) {
readTotal := 0
read, key1, err := p.keyCodec1.DecodeNonTerminal(buffer)
if err != nil {
return 0, Pair[K1, K2]{}, err
}
readTotal += read
read, key2, err := p.keyCodec2.DecodeNonTerminal(buffer[read:])
if err != nil {
return 0, Pair[K1, K2]{}, err
}
readTotal += read
return readTotal, Join(key1, key2), nil
}
func (p pairKeyCodec[K1, K2]) SizeNonTerminal(key Pair[K1, K2]) int {
size := 0
if key.key1 != nil {
size += p.keyCodec1.SizeNonTerminal(*key.key1)
}
if key.key2 != nil {
size += p.keyCodec2.SizeNonTerminal(*key.key2)
}
return size
}
// NewPrefixedPairRange creates a new PairRange which will prefix over all the keys
// starting with the provided prefix.
func NewPrefixedPairRange[K1, K2 any](prefix K1) *PairRange[K1, K2] {
return &PairRange[K1, K2]{
start: RangeKeyExact(PairPrefix[K1, K2](prefix)),
end: RangeKeyPrefixEnd(PairPrefix[K1, K2](prefix)),
}
}
// PairRange is an API that facilitates working with Pair iteration.
// It implements the Ranger API.
// Unstable: API and methods are currently unstable.
type PairRange[K1, K2 any] struct {
start *RangeKey[Pair[K1, K2]]
end *RangeKey[Pair[K1, K2]]
order Order
err error
}
func (p *PairRange[K1, K2]) StartInclusive(k2 K2) *PairRange[K1, K2] {
p.start = RangeKeyExact(Join(*p.start.key.key1, k2))
return p
}
func (p *PairRange[K1, K2]) StartExclusive(k2 K2) *PairRange[K1, K2] {
p.start = RangeKeyNext(Join(*p.start.key.key1, k2))
return p
}
func (p *PairRange[K1, K2]) EndInclusive(k2 K2) *PairRange[K1, K2] {
p.end = RangeKeyNext(Join(*p.end.key.key1, k2))
return p
}
func (p *PairRange[K1, K2]) EndExclusive(k2 K2) *PairRange[K1, K2] {
p.end = RangeKeyExact(Join(*p.end.key.key1, k2))
return p
}
func (p *PairRange[K1, K2]) Descending() *PairRange[K1, K2] {
p.order = OrderDescending
return p
}
func (p *PairRange[K1, K2]) RangeValues() (start *RangeKey[Pair[K1, K2]], end *RangeKey[Pair[K1, K2]], order Order, err error) {
if p.err != nil {
return nil, nil, 0, err
}
return p.start, p.end, p.order, nil
}

65
collections/pair_test.go Normal file
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@ -0,0 +1,65 @@
package collections
import (
"github.com/stretchr/testify/require"
"testing"
)
func TestPair(t *testing.T) {
keyCodec := PairKeyCodec(StringKey, StringKey)
t.Run("correctness", func(t *testing.T) {
checkKeyCodec(t, keyCodec, Join("A", "B"))
})
t.Run("stringify", func(t *testing.T) {
s := keyCodec.Stringify(Join("a", "b"))
require.Equal(t, `("a", "b")`, s)
s = keyCodec.Stringify(PairPrefix[string, string]("a"))
require.Equal(t, `("a", <nil>)`, s)
s = keyCodec.Stringify(Pair[string, string]{})
require.Equal(t, `(<nil>, <nil>)`, s)
})
}
func TestPairRange(t *testing.T) {
sk, ctx := deps()
schema := NewSchemaBuilder(sk)
pc := PairKeyCodec(StringKey, Uint64Key)
m := NewMap(schema, NewPrefix(0), "pair", pc, Uint64Value)
require.NoError(t, m.Set(ctx, Join("A", uint64(0)), 1))
require.NoError(t, m.Set(ctx, Join("A", uint64(1)), 0))
require.NoError(t, m.Set(ctx, Join("A", uint64(2)), 0))
require.NoError(t, m.Set(ctx, Join("B", uint64(3)), 0))
v, err := m.Get(ctx, Join("A", uint64(0)))
require.NoError(t, err)
require.Equal(t, uint64(1), v)
// EXPECT only A1,2
iter, err := m.Iterate(ctx, NewPrefixedPairRange[string, uint64]("A").StartInclusive(1).EndInclusive(2))
require.NoError(t, err)
keys, err := iter.Keys()
require.NoError(t, err)
require.Equal(t, []Pair[string, uint64]{Join("A", uint64(1)), Join("A", uint64(2))}, keys)
// expect the whole "A" prefix
iter, err = m.Iterate(ctx, NewPrefixedPairRange[string, uint64]("A"))
require.NoError(t, err)
keys, err = iter.Keys()
require.NoError(t, err)
require.Equal(t, []Pair[string, uint64]{Join("A", uint64(0)), Join("A", uint64(1)), Join("A", uint64(2))}, keys)
// expect only A1
iter, err = m.Iterate(ctx, NewPrefixedPairRange[string, uint64]("A").StartExclusive(0).EndExclusive(2))
require.NoError(t, err)
keys, err = iter.Keys()
require.NoError(t, err)
require.Equal(t, []Pair[string, uint64]{Join("A", uint64(1))}, keys)
// expect A2, A1
iter, err = m.Iterate(ctx, NewPrefixedPairRange[string, uint64]("A").Descending().StartExclusive(0).EndInclusive(2))
require.NoError(t, err)
keys, err = iter.Keys()
require.Equal(t, []Pair[string, uint64]{Join("A", uint64(2)), Join("A", uint64(1))}, keys)
}