improve validation of the data path

engine.go

@@ -68,15 +68,13 @@ type OptionSetter func(*Engine) error
 // path is where the data files will be stored if the path doesn't exist it will be created
 // the user should have write access to the path otherwise an error will be returned
 func NewEngine(path string, options ...OptionSetter) (*Engine, error) {
-
-	// create the data file directory if it doesn't exist
-	if err := os.MkdirAll(path, 0755); err != nil {
+	if err := validateDataPath(path); err != nil {
 		return nil, err
 	}
-
-	err := validateDataDirAccess(path)
-	if err != nil {
+	if exists, err := dataFileExists(path); err != nil {
 		return nil, err
+	} else if exists {
+		return nil, fmt.Errorf("data file exists we have to index it")
 	}
 
 	lockFile, err := createFlock(path)

path.go

@@ -0,0 +1,100 @@
+package storage
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+const (
+	dataFileFormatSuffix = ".dat"
+)
+
+func validatePathFormat(path string) error {
+	if path == "" || path[len(path)-1] != '/' {
+		return fmt.Errorf("path is mandatory and should end with a /")
+	}
+	return nil
+}
+
+func ensureDataDirectoryExists(path string) error {
+	stat, err := os.Stat(path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			if err := os.MkdirAll(path, 0o755); err != nil {
+				return err
+			} else {
+				return nil
+			}
+		} else {
+			return err
+		}
+	}
+	if !stat.IsDir() {
+		return fmt.Errorf("path is not a directory")
+	}
+	return nil
+}
+
+func validateWriteAccess(path string) error {
+	testPath := filepath.Join(path, "test-access-file")
+	testFile, err := os.OpenFile(testPath, os.O_CREATE|os.O_WRONLY, 0o644)
+	if err != nil {
+		return err
+	}
+
+	_, err = testFile.WriteString("test")
+	if err != nil {
+		return err
+	}
+
+	err = testFile.Close()
+	if err != nil {
+		return err
+	}
+
+	err = os.Remove(testPath)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func validateDataPath(path string) error {
+	if err := validatePathFormat(path); err != nil {
+		return err
+	}
+
+	if err := ensureDataDirectoryExists(path); err != nil {
+		return err
+	}
+
+	if err := validateWriteAccess(path); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func dataFileExists(path string) (bool, error) {
+	exists := false
+	err := filepath.WalkDir(path, func(path string, d os.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		if d.IsDir() {
+			return nil
+		}
+		if info, err := d.Info(); err != nil {
+			return err
+		} else {
+			if info.Size() > 0 && filepath.Ext(path) == dataFileFormatSuffix {
+				exists = true
+				return filepath.SkipDir
+			}
+		}
+		return nil
+	})
+	return exists, err
+}

path_test.go

@@ -0,0 +1,91 @@
+package storage
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestValidatePathFormat(t *testing.T) {
+	tests := []struct {
+		path   string
+		hasErr bool
+	}{
+		{"", true},
+		{"path", true},
+		{"path/", false},
+	}
+
+	for _, test := range tests {
+		err := validatePathFormat(test.path)
+		if test.hasErr {
+			assert.Error(t, err, "Expected an error for path '%s'", test.path)
+		} else {
+			assert.NoError(t, err, "Expected no error for path '%s'", test.path)
+		}
+	}
+}
+
+func TestEnsureDataDirectoryExists(t *testing.T) {
+	tempDir, err := os.MkdirTemp("", "test_storage")
+	require.NoError(t, err)
+	defer os.RemoveAll(tempDir)
+
+	path := filepath.Join(tempDir, "data/")
+	err = ensureDataDirectoryExists(path)
+	require.NoError(t, err, "Failed to ensure directory exists: %v", err)
+
+	_, err = os.Stat(path)
+	require.NoError(t, err, "Directory was not created: %v", err)
+
+	assert.True(t, isDir(path), "Path is not a directory")
+}
+
+func TestValidateWriteAccess(t *testing.T) {
+	tempDir, err := os.MkdirTemp("", "test_storage")
+	require.NoError(t, err)
+	defer os.RemoveAll(tempDir)
+
+	err = validateWriteAccess(tempDir + "/")
+	assert.NoError(t, err, "Failed to test write access: %v", err)
+}
+
+func TestDataFileExists(t *testing.T) {
+	tempDir, err := os.MkdirTemp("", "test_storage")
+	require.NoError(t, err)
+	defer os.RemoveAll(tempDir)
+
+	dataFilePath := filepath.Join(tempDir, "data"+dataFileFormatSuffix)
+	dataFile, err := os.OpenFile(dataFilePath, os.O_CREATE|os.O_WRONLY, 0o644)
+	_, err = dataFile.Write([]byte("test"))
+	require.NoError(t, err, "Failed to write to test .dat file: %v", err)
+
+	exists, err := dataFileExists(tempDir)
+	require.NoError(t, err, "Failed to check if data file exists: %v", err)
+	assert.True(t, exists, "Expected data file to exist")
+}
+
+func TestDataFileNotExists(t *testing.T) {
+	tempDir, err := os.MkdirTemp("", "test_storage")
+	require.NoError(t, err)
+	defer os.RemoveAll(tempDir)
+
+	dataFilePath := filepath.Join(tempDir, "data"+dataFileFormatSuffix)
+	_, err = os.Create(dataFilePath)
+	require.NoError(t, err, "Failed to create test .dat file: %v", err)
+
+	exists, err := dataFileExists(tempDir)
+	require.NoError(t, err, "Failed to check if data file exists: %v", err)
+	assert.False(t, exists, "Expected data file to exist")
+}
+
+func isDir(path string) bool {
+	stat, err := os.Stat(path)
+	if err != nil {
+		return false
+	}
+	return stat.IsDir()
+}

unix.go

@@ -6,8 +6,7 @@ import (
 )
 
 const (
-	lockFileName       = ".lock"
-	testAccessFileName = "test-access-file"
+	lockFileName = ".lock"
 )
 
 func createFlock(path string) (*os.File, error) {
@@ -23,19 +22,3 @@ func createFlock(path string) (*os.File, error) {
 
 	return lockFile, nil
 }
-
-func validateDataDirAccess(path string) error {
-	testFile, err := os.OpenFile(path+testAccessFileName, os.O_CREATE|os.O_WRONLY, 0o644)
-	if err != nil {
-		return err
-	}
-	err = testFile.Close()
-	if err != nil {
-		return err
-	}
-	err = os.Remove(path + testAccessFileName)
-	if err != nil {
-		return err
-	}
-	return nil
-}