internal: create package for unsafe bytes convertion (#8733)

Co-authored-by: Alessio Treglia <alessio@tendermint.com>

internal/conv/doc.go

@@ -0,0 +1,2 @@
+// Package conv provides internal functions for convertions and data manipulation
+package conv

internal/conv/string.go

@@ -0,0 +1,23 @@
+package conv
+
+import (
+	"reflect"
+	"unsafe"
+)
+
+// UnsafeStrToBytes uses unsafe to convert string into byte array. Returned bytes
+// must not be altered after this function is called as it will cause a segmentation fault.
+func UnsafeStrToBytes(s string) []byte {
+	var buf = *(*[]byte)(unsafe.Pointer(&s))
+	(*reflect.SliceHeader)(unsafe.Pointer(&buf)).Cap = len(s)
+	return buf
+}
+
+// UnsafeBytesToStr is meant to make a zero allocation conversion
+// from []byte -> string to speed up operations, it is not meant
+// to be used generally, but for a specific pattern to delete keys
+// from a map.
+func UnsafeBytesToStr(b []byte) string {
+	hdr := (*reflect.StringHeader)(unsafe.Pointer(&b))
+	return *(*string)(unsafe.Pointer(hdr))
+}

internal/conv/string_test.go

@@ -0,0 +1,47 @@
+package conv
+
+import (
+	"runtime"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/suite"
+)
+
+func TestStringSuite(t *testing.T) {
+	suite.Run(t, new(StringSuite))
+}
+
+type StringSuite struct{ suite.Suite }
+
+func unsafeConvertStr() []byte {
+	return UnsafeStrToBytes("abc")
+}
+
+func (s *StringSuite) TestUnsafeStrToBytes() {
+	// we convert in other function to trigger GC. We want to check that
+	// the underlying array in []bytes is accessible after GC will finish swapping.
+	for i := 0; i < 5; i++ {
+		b := unsafeConvertStr()
+		runtime.GC()
+		<-time.NewTimer(2 * time.Millisecond).C
+		b2 := append(b, 'd')
+		s.Equal("abc", string(b))
+		s.Equal("abcd", string(b2))
+	}
+}
+
+func unsafeConvertBytes() string {
+	return UnsafeBytesToStr([]byte("abc"))
+}
+
+func (s *StringSuite) TestUnsafeBytesToStr() {
+	// we convert in other function to trigger GC. We want to check that
+	// the underlying array in []bytes is accessible after GC will finish swapping.
+	for i := 0; i < 5; i++ {
+		str := unsafeConvertBytes()
+		runtime.GC()
+		<-time.NewTimer(2 * time.Millisecond).C
+		s.Equal("abc", str)
+	}
+}

store/cachekv/store.go

@@ -4,14 +4,13 @@ import (
 	"bytes"
 	"container/list"
 	"io"
-	"reflect"
 	"sort"
 	"sync"
 	"time"
-	"unsafe"
 
 	dbm "github.com/tendermint/tm-db"
 
+	"github.com/cosmos/cosmos-sdk/internal/conv"
 	"github.com/cosmos/cosmos-sdk/store/tracekv"
 	"github.com/cosmos/cosmos-sdk/store/types"
 	"github.com/cosmos/cosmos-sdk/telemetry"
@@ -179,35 +178,13 @@ func (store *Store) iterator(start, end []byte, ascending bool) types.Iterator {
 	return newCacheMergeIterator(parent, cache, ascending)
 }
 
-// strToByte is meant to make a zero allocation conversion
-// from string -> []byte to speed up operations, it is not meant
-// to be used generally, but for a specific pattern to check for available
-// keys within a domain.
-func strToByte(s string) []byte {
-	var b []byte
-	hdr := (*reflect.SliceHeader)(unsafe.Pointer(&b))
-	hdr.Cap = len(s)
-	hdr.Len = len(s)
-	hdr.Data = (*reflect.StringHeader)(unsafe.Pointer(&s)).Data
-	return b
-}
-
-// byteSliceToStr is meant to make a zero allocation conversion
-// from []byte -> string to speed up operations, it is not meant
-// to be used generally, but for a specific pattern to delete keys
-// from a map.
-func byteSliceToStr(b []byte) string {
-	hdr := (*reflect.StringHeader)(unsafe.Pointer(&b))
-	return *(*string)(unsafe.Pointer(hdr))
-}
-
 // Constructs a slice of dirty items, to use w/ memIterator.
 func (store *Store) dirtyItems(start, end []byte) {
 	unsorted := make([]*kv.Pair, 0)
 
 	n := len(store.unsortedCache)
 	for key := range store.unsortedCache {
-		if dbm.IsKeyInDomain(strToByte(key), start, end) {
+		if dbm.IsKeyInDomain(conv.UnsafeStrToBytes(key), start, end) {
 			cacheValue := store.cache[key]
 			unsorted = append(unsorted, &kv.Pair{Key: []byte(key), Value: cacheValue.value})
 		}
@@ -219,7 +196,7 @@ func (store *Store) dirtyItems(start, end []byte) {
 		}
 	} else { // Otherwise, normally delete the unsorted keys from the map.
 		for _, kv := range unsorted {
-			delete(store.unsortedCache, byteSliceToStr(kv.Key))
+			delete(store.unsortedCache, conv.UnsafeBytesToStr(kv.Key))
 		}
 	}
 

types/address/hash.go

@@ -4,10 +4,9 @@ import (
 	"bytes"
 	"crypto/sha256"
 	"fmt"
-	"reflect"
 	"sort"
-	"unsafe"
 
+	"github.com/cosmos/cosmos-sdk/internal/conv"
 	"github.com/cosmos/cosmos-sdk/types/errors"
 )
 
@@ -21,7 +20,7 @@ type Addressable interface {
 // Hash creates a new address from address type and key
 func Hash(typ string, key []byte) []byte {
 	hasher := sha256.New()
-	hasher.Write(unsafeStrToByteArray(typ))
+	hasher.Write(conv.UnsafeStrToBytes(typ))
 	th := hasher.Sum(nil)
 
 	hasher.Reset()
@@ -63,11 +62,3 @@ func Module(moduleName string, key []byte) []byte {
 	mKey := append([]byte(moduleName), 0)
 	return Hash("module", append(mKey, key...))
 }
-
-// unsafeStrToByteArray uses unsafe to convert string into byte array. Returned bytes
-// must not be altered after this function is called as it will cause a segmentation fault.
-func unsafeStrToByteArray(s string) []byte {
-	var buf = *(*[]byte)(unsafe.Pointer(&s))
-	(*reflect.SliceHeader)(unsafe.Pointer(&buf)).Cap = len(s)
-	return buf
-}

types/address/hash_test.go

@@ -2,9 +2,7 @@ package address
 
 import (
 	"crypto/sha256"
-	"runtime"
 	"testing"
-	"time"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/suite"
@@ -77,23 +75,6 @@ func (suite *AddressSuite) TestModule() {
 	assert.NotEqual(addr2, addr3, "changing key must change address")
 }
 
-func unsafeConvertABC() []byte {
-	return unsafeStrToByteArray("abc")
-}
-
-func (suite *AddressSuite) TestUnsafeStrToBytes() {
-	// we convert in other function to trigger GC. We want to check that
-	// the underlying array in []bytes is accessible after GC will finish swapping.
-	for i := 0; i < 5; i++ {
-		b := unsafeConvertABC()
-		runtime.GC()
-		<-time.NewTimer(2 * time.Millisecond).C
-		b2 := append(b, 'd')
-		suite.Equal("abc", string(b))
-		suite.Equal("abcd", string(b2))
-	}
-}
-
 type addrMock struct {
 	Addr []byte
 }