sort using slices.Sort (#243)

- Update sorting to use `slices.Sort` for improved efficiency.
- Add `Key.Compare` to compare datastore keys when sorting.
- Add `query.Compare` function to compare Entry values according to orders.
- Remove unnecessary slice copy when reversing key.
- Additional updates for code conventions.

Author: gammazero

autobatch/autobatch.go

@@ -117,7 +117,7 @@ func (d *Datastore) Flush(ctx context.Context) error {
 		}
 	}
 	// clear out buffer
-	d.buffer = make(map[ds.Key]op, d.maxBufferEntries)
+	clear(d.buffer)
 
 	return b.Commit(ctx)
 }

basic_ds.go

@@ -27,7 +27,7 @@ func NewMapDatastore() (d *MapDatastore) {
 }
 
 // Put implements Datastore.Put
-func (d *MapDatastore) Put(ctx context.Context, key Key, value []byte) (err error) {
+func (d *MapDatastore) Put(ctx context.Context, key Key, value []byte) error {
 	d.values[key] = value
 	return nil
 }
@@ -38,7 +38,7 @@ func (d *MapDatastore) Sync(ctx context.Context, prefix Key) error {
 }
 
 // Get implements Datastore.Get
-func (d *MapDatastore) Get(ctx context.Context, key Key) (value []byte, err error) {
+func (d *MapDatastore) Get(ctx context.Context, key Key) ([]byte, error) {
 	val, found := d.values[key]
 	if !found {
 		return nil, ErrNotFound
@@ -47,21 +47,21 @@ func (d *MapDatastore) Get(ctx context.Context, key Key) (value []byte, err erro
 }
 
 // Has implements Datastore.Has
-func (d *MapDatastore) Has(ctx context.Context, key Key) (exists bool, err error) {
+func (d *MapDatastore) Has(ctx context.Context, key Key) (bool, error) {
 	_, found := d.values[key]
 	return found, nil
 }
 
 // GetSize implements Datastore.GetSize
-func (d *MapDatastore) GetSize(ctx context.Context, key Key) (size int, err error) {
+func (d *MapDatastore) GetSize(ctx context.Context, key Key) (int, error) {
 	if v, found := d.values[key]; found {
 		return len(v), nil
 	}
 	return -1, ErrNotFound
 }
 
 // Delete implements Datastore.Delete
-func (d *MapDatastore) Delete(ctx context.Context, key Key) (err error) {
+func (d *MapDatastore) Delete(ctx context.Context, key Key) error {
 	delete(d.values, key)
 	return nil
 }
@@ -124,7 +124,7 @@ func (d *LogDatastore) Children() []Datastore {
 }
 
 // Put implements Datastore.Put
-func (d *LogDatastore) Put(ctx context.Context, key Key, value []byte) (err error) {
+func (d *LogDatastore) Put(ctx context.Context, key Key, value []byte) error {
 	log.Printf("%s: Put %s\n", d.Name, key)
 	// log.Printf("%s: Put %s ```%s```", d.Name, key, value)
 	return d.child.Put(ctx, key, value)
@@ -137,25 +137,25 @@ func (d *LogDatastore) Sync(ctx context.Context, prefix Key) error {
 }
 
 // Get implements Datastore.Get
-func (d *LogDatastore) Get(ctx context.Context, key Key) (value []byte, err error) {
+func (d *LogDatastore) Get(ctx context.Context, key Key) ([]byte, error) {
 	log.Printf("%s: Get %s\n", d.Name, key)
 	return d.child.Get(ctx, key)
 }
 
 // Has implements Datastore.Has
-func (d *LogDatastore) Has(ctx context.Context, key Key) (exists bool, err error) {
+func (d *LogDatastore) Has(ctx context.Context, key Key) (bool, error) {
 	log.Printf("%s: Has %s\n", d.Name, key)
 	return d.child.Has(ctx, key)
 }
 
 // GetSize implements Datastore.GetSize
-func (d *LogDatastore) GetSize(ctx context.Context, key Key) (size int, err error) {
+func (d *LogDatastore) GetSize(ctx context.Context, key Key) (int, error) {
 	log.Printf("%s: GetSize %s\n", d.Name, key)
 	return d.child.GetSize(ctx, key)
 }
 
 // Delete implements Datastore.Delete
-func (d *LogDatastore) Delete(ctx context.Context, key Key) (err error) {
+func (d *LogDatastore) Delete(ctx context.Context, key Key) error {
 	log.Printf("%s: Delete %s\n", d.Name, key)
 	return d.child.Delete(ctx, key)
 }
@@ -203,20 +203,20 @@ func (d *LogDatastore) Batch(ctx context.Context) (Batch, error) {
 }
 
 // Put implements Batch.Put
-func (d *LogBatch) Put(ctx context.Context, key Key, value []byte) (err error) {
+func (d *LogBatch) Put(ctx context.Context, key Key, value []byte) error {
 	log.Printf("%s: BatchPut %s\n", d.Name, key)
 	// log.Printf("%s: Put %s ```%s```", d.Name, key, value)
 	return d.child.Put(ctx, key, value)
 }
 
 // Delete implements Batch.Delete
-func (d *LogBatch) Delete(ctx context.Context, key Key) (err error) {
+func (d *LogBatch) Delete(ctx context.Context, key Key) error {
 	log.Printf("%s: BatchDelete %s\n", d.Name, key)
 	return d.child.Delete(ctx, key)
 }
 
 // Commit implements Batch.Commit
-func (d *LogBatch) Commit(ctx context.Context) (err error) {
+func (d *LogBatch) Commit(ctx context.Context) error {
 	log.Printf("%s: BatchCommit\n", d.Name)
 	return d.child.Commit(ctx)
 }

datastore.go

@@ -206,14 +206,13 @@ var ErrNotFound error = &dsError{error: errors.New("datastore: key not found"),
 //	}
 func GetBackedHas(ctx context.Context, ds Read, key Key) (bool, error) {
 	_, err := ds.Get(ctx, key)
-	switch err {
-	case nil:
-		return true, nil
-	case ErrNotFound:
-		return false, nil
-	default:
+	if err != nil {
+		if err == ErrNotFound {
+			return false, nil
+		}
 		return false, err
 	}
+	return true, nil
 }
 
 // GetBackedSize provides a default Datastore.GetSize implementation.
@@ -224,10 +223,10 @@ func GetBackedHas(ctx context.Context, ds Read, key Key) (bool, error) {
 //	}
 func GetBackedSize(ctx context.Context, ds Read, key Key) (int, error) {
 	value, err := ds.Get(ctx, key)
-	if err == nil {
-		return len(value), nil
+	if err != nil {
+		return -1, err
 	}
-	return -1, err
+	return len(value), nil
 }
 
 type Batch interface {

key.go

@@ -3,6 +3,7 @@ package datastore
 import (
 	"encoding/json"
 	"path"
+	"slices"
 	"strings"
 
 	dsq "github.com/ipfs/go-datastore/query"
@@ -90,26 +91,37 @@ func (k Key) Equal(k2 Key) bool {
 	return k.string == k2.string
 }
 
-// Less checks whether this key is sorted lower than another.
-func (k Key) Less(k2 Key) bool {
+// Compare returns -1 if this key is sorted lower than another, 1 if this key
+// is sorted greater that another, and 0 if the two keys sort the same.
+func (k Key) Compare(k2 Key) int {
 	list1 := k.List()
 	list2 := k2.List()
+	list2end := len(list2) - 1
 	for i, c1 := range list1 {
-		if len(list2) < (i + 1) {
-			return false
+		if list2end < i {
+			return 1
 		}
-
 		c2 := list2[i]
 		if c1 < c2 {
-			return true
-		} else if c1 > c2 {
-			return false
+			return -1
+		}
+		if c1 > c2 {
+			return 1
 		}
 		// c1 == c2, continue
 	}
 
-	// list1 is shorter or exactly the same.
-	return len(list1) < len(list2)
+	// if list1 is shorter.
+	if len(list1) < len(list2) {
+		return -1
+	}
+	// Lists are the same.
+	return 0
+}
+
+// Less checks whether this key is sorted lower than another.
+func (k Key) Less(k2 Key) bool {
+	return k.Compare(k2) == -1
 }
 
 // List returns the `list` representation of this Key.
@@ -126,11 +138,8 @@ func (k Key) List() []string {
 //	NewKey("/Actor:JohnCleese/MontyPython/Comedy")
 func (k Key) Reverse() Key {
 	l := k.List()
-	r := make([]string, len(l))
-	for i, e := range l {
-		r[len(l)-i-1] = e
-	}
-	return KeyWithNamespaces(r)
+	slices.Reverse(l)
+	return KeyWithNamespaces(l)
 }
 
 // Namespaces returns the `namespaces` making up this Key.

keytransform/keytransform.go

@@ -130,13 +130,12 @@ orders:
 			continue
 		case dsq.OrderByKey, *dsq.OrderByKey,
 			dsq.OrderByKeyDescending, *dsq.OrderByKeyDescending:
-			// if the key transform preserves order, we can delegate
-			// to the child datastore.
+			// if the key transform preserves order, we can delegate to the
+			// child datastore.
 			if orderPreserving {
-				// When sorting, we compare with the first
-				// Order, then, if equal, we compare with the
-				// second Order, etc. However, keys are _unique_
-				// so we'll never apply any additional orders
+				// When sorting, we compare with the first Order, then, if
+				// equal, we compare with the second Order, etc. However, keys
+				// are _unique_ so we'll never apply any additional orders
 				// after ordering by key.
 				child.Orders = child.Orders[:i+1]
 				break orders

keytransform/keytransform_test.go

@@ -2,7 +2,7 @@ package keytransform_test
 
 import (
 	"context"
-	"sort"
+	"slices"
 	"testing"
 
 	ds "github.com/ipfs/go-datastore"
@@ -71,8 +71,12 @@ func TestBasic(t *testing.T) {
 	require.Equal(t, len(listA), len(listB))
 
 	// sort them cause yeah.
-	sort.Sort(ds.KeySlice(listA))
-	sort.Sort(ds.KeySlice(listB))
+	slices.SortFunc(listA, func(a, b ds.Key) int {
+		return a.Compare(b)
+	})
+	slices.SortFunc(listB, func(a, b ds.Key) int {
+		return a.Compare(b)
+	})
 
 	for i, kA := range listA {
 		kB := listB[i]

mount/mount.go

@@ -7,7 +7,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"sort"
+	"slices"
 	"strings"
 	"sync"
 
@@ -33,9 +33,10 @@ type Mount struct {
 // to least specific.
 func New(mounts []Mount) *Datastore {
 	// make a copy so we're sure it doesn't mutate
-	m := make([]Mount, len(mounts))
-	copy(m, mounts)
-	sort.Slice(m, func(i, j int) bool { return m[i].Prefix.String() > m[j].Prefix.String() })
+	m := slices.Clone(mounts)
+	slices.SortFunc(m, func(a, b Mount) int {
+		return strings.Compare(b.Prefix.String(), a.Prefix.String())
+	})
 	return &Datastore{mounts: m}
 }
 

namespace/namespace_test.go

@@ -2,7 +2,8 @@ package namespace_test
 
 import (
 	"context"
-	"sort"
+	"slices"
+	"strings"
 	"testing"
 
 	ds "github.com/ipfs/go-datastore"
@@ -62,8 +63,12 @@ func testBasic(t *testing.T, prefix string) {
 	require.Equal(t, len(listA), len(listB))
 
 	// sort them cause yeah.
-	sort.Sort(ds.KeySlice(listA))
-	sort.Sort(ds.KeySlice(listB))
+	slices.SortFunc(listA, func(a, b ds.Key) int {
+		return a.Compare(b)
+	})
+	slices.SortFunc(listB, func(a, b ds.Key) int {
+		return a.Compare(b)
+	})
 
 	for i, kA := range listA {
 		kB := listB[i]
@@ -103,7 +108,9 @@ func TestQuery(t *testing.T) {
 
 	results, err := qres.Rest()
 	require.NoError(t, err)
-	sort.Slice(results, func(i, j int) bool { return results[i].Key < results[j].Key })
+	slices.SortFunc(results, func(a, b dsq.Entry) int {
+		return strings.Compare(a.Key, b.Key)
+	})
 
 	for i, ent := range results {
 		require.Equal(t, expect[i].Key, ent.Key)
@@ -121,7 +128,9 @@ func TestQuery(t *testing.T) {
 
 	results, err = qres.Rest()
 	require.NoError(t, err)
-	sort.Slice(results, func(i, j int) bool { return results[i].Key < results[j].Key })
+	slices.SortFunc(results, func(a, b dsq.Entry) int {
+		return strings.Compare(a.Key, b.Key)
+	})
 
 	for i, ent := range results {
 		require.Equal(t, expect[i].Key, ent.Key)

null_ds.go

@@ -25,7 +25,7 @@ func NewNullDatastore() *NullDatastore {
 }
 
 // Put implements Datastore.Put
-func (d *NullDatastore) Put(ctx context.Context, key Key, value []byte) (err error) {
+func (d *NullDatastore) Put(ctx context.Context, key Key, value []byte) error {
 	return nil
 }
 
@@ -35,22 +35,22 @@ func (d *NullDatastore) Sync(ctx context.Context, prefix Key) error {
 }
 
 // Get implements Datastore.Get
-func (d *NullDatastore) Get(ctx context.Context, key Key) (value []byte, err error) {
+func (d *NullDatastore) Get(ctx context.Context, key Key) ([]byte, error) {
 	return nil, ErrNotFound
 }
 
 // Has implements Datastore.Has
-func (d *NullDatastore) Has(ctx context.Context, key Key) (exists bool, err error) {
+func (d *NullDatastore) Has(ctx context.Context, key Key) (bool, error) {
 	return false, nil
 }
 
 // Has implements Datastore.GetSize
-func (d *NullDatastore) GetSize(ctx context.Context, key Key) (size int, err error) {
+func (d *NullDatastore) GetSize(ctx context.Context, key Key) (int, error) {
 	return -1, ErrNotFound
 }
 
 // Delete implements Datastore.Delete
-func (d *NullDatastore) Delete(ctx context.Context, key Key) (err error) {
+func (d *NullDatastore) Delete(ctx context.Context, key Key) error {
 	return nil
 }
 
@@ -89,15 +89,15 @@ func (d *NullDatastore) NewTransaction(ctx context.Context, readOnly bool) (Txn,
 
 type nullTxn struct{}
 
-func (t *nullTxn) Get(ctx context.Context, key Key) (value []byte, err error) {
+func (t *nullTxn) Get(ctx context.Context, key Key) ([]byte, error) {
 	return nil, nil
 }
 
-func (t *nullTxn) Has(ctx context.Context, key Key) (exists bool, err error) {
+func (t *nullTxn) Has(ctx context.Context, key Key) (bool, error) {
 	return false, nil
 }
 
-func (t *nullTxn) GetSize(ctx context.Context, key Key) (size int, err error) {
+func (t *nullTxn) GetSize(ctx context.Context, key Key) (int, error) {
 	return 0, nil
 }