From e90144cf0a84c2a309981ed1c8d160fc24dfb2d2 Mon Sep 17 00:00:00 2001
From: Wondertan <hlibwondertan@gmail.com>
Date: Wed, 30 Jul 2025 22:00:45 +0200
Subject: [PATCH 1/3] feat(keytransform): support transction feature

---
 keytransform/keytransform.go | 60 ++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/keytransform/keytransform.go b/keytransform/keytransform.go
index c1c74149..2f7413b0 100644
--- a/keytransform/keytransform.go
+++ b/keytransform/keytransform.go
@@ -2,6 +2,7 @@ package keytransform
 
 import (
 	"context"
+	"fmt"
 
 	ds "github.com/ipfs/go-datastore"
 	dsq "github.com/ipfs/go-datastore/query"
@@ -31,6 +32,7 @@ type Datastore struct {
 
 var _ ds.Datastore = (*Datastore)(nil)
 var _ ds.Batching = (*Datastore)(nil)
+var _ ds.TxnDatastore = (*Datastore)(nil)
 var _ ds.Shim = (*Datastore)(nil)
 var _ ds.PersistentDatastore = (*Datastore)(nil)
 var _ ds.CheckedDatastore = (*Datastore)(nil)
@@ -224,6 +226,23 @@ func (d *Datastore) Batch(ctx context.Context) (ds.Batch, error) {
 	}, nil
 }
 
+func (d *Datastore) NewTransaction(ctx context.Context, readOnly bool) (ds.Txn, error) {
+	tds, ok := d.child.(ds.TxnDatastore)
+	if !ok {
+		return nil, fmt.Errorf("txn not supported")
+	}
+
+	childTxn, err := tds.NewTransaction(ctx, readOnly)
+	if err != nil {
+		return nil, err
+	}
+
+	return &transformTxn{
+		dst: childTxn,
+		f:   d.ConvertKey,
+	}, nil
+}
+
 type transformBatch struct {
 	dst ds.Batch
 
@@ -244,6 +263,47 @@ func (t *transformBatch) Commit(ctx context.Context) error {
 	return t.dst.Commit(ctx)
 }
 
+type transformTxn struct {
+	ds  *Datastore
+	dst ds.Txn
+
+	f KeyMapping
+}
+
+var _ ds.Txn = (*transformTxn)(nil)
+
+func (t *transformTxn) Put(ctx context.Context, key ds.Key, val []byte) error {
+	return t.dst.Put(ctx, t.f(key), val)
+}
+
+func (t *transformTxn) Delete(ctx context.Context, key ds.Key) error {
+	return t.dst.Delete(ctx, t.f(key))
+}
+
+func (t *transformTxn) Commit(ctx context.Context) error {
+	return t.dst.Commit(ctx)
+}
+
+func (t *transformTxn) Get(ctx context.Context, key ds.Key) (value []byte, err error) {
+	return t.dst.Get(ctx, t.f(key))
+}
+
+func (t *transformTxn) Has(ctx context.Context, key ds.Key) (exists bool, err error) {
+	return t.dst.Has(ctx, t.f(key))
+}
+
+func (t *transformTxn) GetSize(ctx context.Context, key ds.Key) (size int, err error) {
+	return t.dst.GetSize(ctx, t.f(key))
+}
+
+func (t *transformTxn) Query(ctx context.Context, q dsq.Query) (dsq.Results, error) {
+	return t.ds.Query(ctx, q)
+}
+
+func (t *transformTxn) Discard(ctx context.Context) {
+	t.dst.Discard(ctx)
+}
+
 func (d *Datastore) Check(ctx context.Context) error {
 	if c, ok := d.child.(ds.CheckedDatastore); ok {
 		return c.Check(ctx)

From de4fd817859c5860766a64e7c17f853494bf683d Mon Sep 17 00:00:00 2001
From: Wondertan <hlibwondertan@gmail.com>
Date: Wed, 30 Jul 2025 23:38:00 +0200
Subject: [PATCH 2/3] nit

---
 keytransform/keytransform.go | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/keytransform/keytransform.go b/keytransform/keytransform.go
index 2f7413b0..1ce1418e 100644
--- a/keytransform/keytransform.go
+++ b/keytransform/keytransform.go
@@ -2,7 +2,7 @@ package keytransform
 
 import (
 	"context"
-	"fmt"
+	"errors"
 
 	ds "github.com/ipfs/go-datastore"
 	dsq "github.com/ipfs/go-datastore/query"
@@ -229,7 +229,7 @@ func (d *Datastore) Batch(ctx context.Context) (ds.Batch, error) {
 func (d *Datastore) NewTransaction(ctx context.Context, readOnly bool) (ds.Txn, error) {
 	tds, ok := d.child.(ds.TxnDatastore)
 	if !ok {
-		return nil, fmt.Errorf("txn not supported")
+		return nil, errors.New("keytransform: transaction feature not supported")
 	}
 
 	childTxn, err := tds.NewTransaction(ctx, readOnly)

From 4d3eeae52ad27434e487122c9e65742bbb3e653a Mon Sep 17 00:00:00 2001
From: Wondertan <hlibwondertan@gmail.com>
Date: Fri, 1 Aug 2025 03:26:54 +0200
Subject: [PATCH 3/3] avoid conversion if already converted

---
 keytransform/transforms.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/keytransform/transforms.go b/keytransform/transforms.go
index cc39897e..143a622e 100644
--- a/keytransform/transforms.go
+++ b/keytransform/transforms.go
@@ -29,6 +29,10 @@ type PrefixTransform struct {
 
 // ConvertKey adds the prefix.
 func (p PrefixTransform) ConvertKey(k ds.Key) ds.Key {
+	if p.Prefix.IsAncestorOf(k) {
+		return k
+	}
+
 	return p.Prefix.Child(k)
 }