New version

* Simplify internal structures
* Update minimal Go version
* Add Delete() function

errors.go

@@ -0,0 +1,5 @@
+package zkv
+
+import "errors"
+
+var ErrNotExists = errors.New("not exists")

go.mod

@@ -1,14 +1,14 @@
 module github.com/nxshock/zkv
 
-go 1.17
+go 1.19
 
 require (
-	github.com/klauspost/compress v1.14.2
+	github.com/klauspost/compress v1.15.12
-	github.com/stretchr/testify v1.7.0
+	github.com/stretchr/testify v1.8.1
 )
 
 require (
-	github.com/davecgh/go-spew v1.1.0 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -1,13 +1,19 @@
-github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/klauspost/compress v1.14.2 h1:S0OHlFk/Gbon/yauFJ4FfJJF5V0fc5HbBTJazi28pRw=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
-github.com/klauspost/compress v1.14.2/go.mod h1:/3/Vjq9QcHkK5uEr5lBEmyoZ1iFhe47etQ6QUkpK6sk=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/klauspost/compress v1.15.12 h1:YClS/PImqYbn+UILDnqxQCZ3RehC9N318SU3kElDUEM=
+github.com/klauspost/compress v1.15.12/go.mod h1:QPwzmACJjUTFsnSHH934V6woptycfrDDJnH7hvFVbGM=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
-github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
+github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
+github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

record.go

@@ -15,10 +15,9 @@ const (
 )
 
 type Record struct {
-	Type       RecordType `json:"t"`
+	Type       RecordType
-	KeyHash    []byte     `json:"h"`
+	KeyHash    []byte
-	KeyBytes   []byte     `json:"k,omitempty"` // optional
+	ValueBytes []byte
-	ValueBytes []byte     `json:"v"`
 }
 
 func newRecord(recordType RecordType, key, value interface{}) (*Record, error) {
@@ -35,7 +34,6 @@ func newRecord(recordType RecordType, key, value interface{}) (*Record, error) {
 	record := &Record{
 		Type:       recordType,
 		KeyHash:    hashBytes(keyBytes),
-		KeyBytes:   keyBytes,
 		ValueBytes: valueBytes}
 
 	return record, nil

utils.go

@@ -5,7 +5,6 @@ import (
 	"crypto/sha256"
 	"encoding/gob"
 	"io"
-	"io/ioutil"
 )
 
 func encode(value interface{}) ([]byte, error) {
@@ -39,7 +38,7 @@ func skip(r io.Reader, count int64) (err error) {
 	case io.Seeker:
 		_, err = r.Seek(count, io.SeekCurrent)
 	default:
-		_, err = io.CopyN(ioutil.Discard, r, count)
+		_, err = io.CopyN(io.Discard, r, count)
 	}
 
 	return err

zkv.go

@@ -3,7 +3,6 @@ package zkv
 import (
 	"bytes"
 	"encoding/base64"
-	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -12,10 +11,6 @@ import (
 	"github.com/klauspost/compress/zstd"
 )
 
-type Options struct {
-	SaveKeys bool
-}
-
 type Database struct {
 	dataOffset map[string]int64
 	file       *os.File
@@ -23,8 +18,6 @@ type Database struct {
 	filePath   string
 	offset     int64
 
-	options Options
-
 	mu sync.Mutex
 }
 
@@ -49,10 +42,6 @@ func (db *Database) Set(key, value interface{}) error {
 		return err
 	}
 
-	if !db.options.SaveKeys {
-		record.KeyBytes = nil
-	}
-
 	b, err := record.Marshal()
 	if err != nil {
 		return err
@@ -81,7 +70,7 @@ func (db *Database) Get(key, value interface{}) error {
 
 	offset, exists := db.dataOffset[string(hashToFind)]
 	if !exists {
-		return errors.New("not exists") // TODO: заменить на константную ошибку
+		return ErrNotExists
 	}
 
 	readF, err := os.Open(db.filePath)
@@ -106,7 +95,7 @@ func (db *Database) Get(key, value interface{}) error {
 		return err
 	}
 
-	if bytes.Compare(record.KeyHash, hashToFind) != 0 {
+	if !bytes.Equal(record.KeyHash, hashToFind) {
 		return fmt.Errorf("wrong hash on this offset: expected %s, got %s", base64.StdEncoding.EncodeToString(hashToFind), base64.StdEncoding.EncodeToString(record.KeyHash)) // TODO: заменить на константную ошибку
 	}
 
@@ -168,3 +157,34 @@ func Open(filePath string) (*Database, error) {
 
 	return database, nil
 }
+
+func (db *Database) Delete(key interface{}) error {
+	db.mu.Lock()
+	defer db.mu.Unlock()
+
+	keyHash, err := hashInterface(key)
+	if err != nil {
+		return err
+	}
+
+	record := &Record{
+		Type:    RecordTypeDelete,
+		KeyHash: keyHash,
+	}
+
+	b, err := record.Marshal()
+	if err != nil {
+		return err
+	}
+
+	delete(db.dataOffset, string(record.KeyHash))
+
+	_, err = db.compressor.Write(b)
+	if err != nil {
+		return err
+	}
+
+	db.offset += int64(len(b))
+
+	return nil
+}

zkv_test.go

@@ -77,3 +77,44 @@ func TestSmallWrites(t *testing.T) {
 	err = db.Close()
 	assert.NoError(t, err)
 }
+
+func TestDeleteBasic(t *testing.T) {
+	const filePath = "TestDeleteBasic.zkv"
+	const recordCount = 100
+	defer os.Remove(filePath)
+
+	db, err := Open(filePath)
+	assert.NoError(t, err)
+
+	for i := 1; i <= recordCount; i++ {
+		err = db.Set(i, i)
+		assert.NoError(t, err)
+	}
+
+	assert.Len(t, db.dataOffset, recordCount)
+
+	err = db.Delete(50)
+	assert.NoError(t, err)
+
+	assert.Len(t, db.dataOffset, recordCount-1)
+	var value int
+	err = db.Get(50, &value)
+	assert.Equal(t, 0, value)
+	assert.ErrorIs(t, err, ErrNotExists)
+
+	err = db.Close()
+	assert.NoError(t, err)
+
+	// try to read
+	db, err = Open(filePath)
+	assert.NoError(t, err)
+
+	assert.Len(t, db.dataOffset, recordCount-1)
+	value = 0
+	err = db.Get(50, &value)
+	assert.Equal(t, 0, value)
+	assert.ErrorIs(t, err, ErrNotExists)
+
+	err = db.Close()
+	assert.NoError(t, err)
+}