simplify code using slices package (#232)

Author: gammazero

cache/radixcache/radixcache.go

@@ -3,6 +3,7 @@ package radixcache
 import (
 	"bytes"
 	"context"
+	"slices"
 	"strings"
 	"sync"
 
@@ -389,8 +390,7 @@ func (c *radixCache) internValue(value *indexer.Value, updateMeta, saveNew bool)
 		// If the provided value has matching ProviderID and ContextID but
 		// different Metadata, then update the interned value's metadata.
 		if updateMeta && !bytes.Equal(v.MetadataBytes, value.MetadataBytes) {
-			v.MetadataBytes = make([]byte, len(value.MetadataBytes))
-			copy(v.MetadataBytes, value.MetadataBytes)
+			v.MetadataBytes = slices.Clone(value.MetadataBytes)
 		}
 		return v
 	}

engine/engine.go

@@ -2,6 +2,7 @@ package engine
 
 import (
 	"context"
+	"slices"
 	"sync/atomic"
 	"time"
 
@@ -86,13 +87,13 @@ func (e *Engine) Put(value indexer.Value, mhs ...multihash.Multihash) error {
 	mhsCount := len(mhs)
 
 	if e.resultCache != nil {
-		var addToCache, mhsCopy []multihash.Multihash
+		var addToCache []multihash.Multihash
+		var copied bool
 		// If using a value store, make sure give a copy of mhs to the
 		// valuestore, as some implementations may expect to take ownership.
 		if e.valueStore != nil {
-			mhsCopy = make([]multihash.Multihash, len(mhs))
-			copy(mhsCopy, mhs)
-			mhs = mhsCopy
+			mhs = slices.Clone(mhs)
+			copied = true
 		}
 
 		for i := 0; i < len(mhs); {
@@ -114,11 +115,10 @@ func (e *Engine) Put(value indexer.Value, mhs ...multihash.Multihash) error {
 					// value, so do not try to put it in the value store. The
 					// value store will handle this, but at a higher cost
 					// requiring reading from disk.
-					if mhsCopy == nil {
+					if !copied {
 						// Copy-on-write
-						mhsCopy = make([]multihash.Multihash, len(mhs))
-						copy(mhsCopy, mhs)
-						mhs = mhsCopy
+						mhs = slices.Clone(mhs)
+						copied = true
 					}
 					mhs[i] = mhs[len(mhs)-1]
 					mhs[len(mhs)-1] = nil

store/memory/memory.go

@@ -251,8 +251,7 @@ func (s *memoryStore) internValue(value *indexer.Value, saveNew bool) *indexer.V
 		// The provided value has matching ProviderID and ContextID but
 		// different Metadata.  Treat this as an update.
 		if !bytes.Equal(v.MetadataBytes, value.MetadataBytes) {
-			v.MetadataBytes = make([]byte, len(value.MetadataBytes))
-			copy(v.MetadataBytes, value.MetadataBytes)
+			v.MetadataBytes = bytes.Clone(value.MetadataBytes)
 		}
 		return v
 	}

store/pebble/key.go

@@ -1,6 +1,7 @@
 package pebble
 
 import (
+	"bytes"
 	"errors"
 	"io"
 
@@ -224,15 +225,10 @@ func (b *blake3Keyer) multihashKey(mh multihash.Multihash) (*key, error) {
 // keyToMultihash extracts the multihash to which the given key is associated.
 // An error is returned if the given key does not have multihashKeyPrefix.
 func (b *blake3Keyer) keyToMultihash(k *key) (multihash.Multihash, error) {
-	switch k.prefix() {
-	case multihashKeyPrefix:
-		keyData := k.buf[1:]
-		mh := make([]byte, len(keyData))
-		copy(mh, keyData)
-		return mh, nil
-	default:
+	if k.prefix() != multihashKeyPrefix {
 		return nil, errors.New("key prefix mismatch")
 	}
+	return bytes.Clone(k.buf[1:]), nil
 }
 
 func (b *blake3Keyer) Close() error {

store/pebble/vk_merger.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"errors"
 	"io"
+	"slices"
 
 	"github.com/cockroachdb/pebble"
 )
@@ -97,9 +98,7 @@ func (v *valueKeysValueMerger) Finish(_ bool) ([]byte, io.Closer, error) {
 		return nil, nil, nil
 	}
 	if v.reverse {
-		for one, other := 0, len(v.merges)-1; one < other; one, other = one+1, other-1 {
-			v.merges[one], v.merges[other] = v.merges[other], v.merges[one]
-		}
+		slices.Reverse(v.merges)
 	}
 	return v.c.marshalValueKeys(v.merges)
 }
@@ -111,21 +110,16 @@ func (v *valueKeysValueMerger) DeletableFinish(includesBase bool) ([]byte, bool,
 
 // prune removes value-keys that are present in deletes from merges
 func (v *valueKeysValueMerger) prune() {
-	pruned := v.merges[:0]
-	for _, x := range v.merges {
-		if _, ok := v.deletes[string(x)]; !ok {
-			pruned = append(pruned, x)
-		}
-	}
-	v.merges = pruned
+	v.merges = slices.DeleteFunc(v.merges, func(vk []byte) bool {
+		_, ok := v.deletes[string(vk)]
+		return ok
+	})
 }
 
 // addToMerges checks whether the given value exists and if not adds it to the list of merges.
 func (v *valueKeysValueMerger) addToMerges(value []byte) {
 	if !v.exists(value) {
-		dst := make([]byte, len(value))
-		copy(dst, value)
-		v.merges = append(v.merges, dst)
+		v.merges = append(v.merges, bytes.Clone(value))
 	}
 }