api socket.filemode

Author: SuperBuker

api/socket/filemode.go

@@ -0,0 +1,81 @@
+package socket
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/fs"
+	"regexp"
+	"strconv"
+)
+
+var ErrUnsupportedBase = errors.New("unsuported base")
+var ErrInvalidNumber = errors.New("value doesn't correspond with base")
+var ErrInvalidPermissions = errors.New("invalid file permissions")
+
+// Validate number corresponds with base
+func validateBase(s string, base uint32) error {
+	// Only bases up to 10 are supported, this might chante in the future.
+	if base == 0 || base > 10 {
+		return ErrUnsupportedBase
+	}
+
+	pattern := fmt.Sprintf("^[0-%v]{3}$", base-1)
+
+	if match, err := regexp.MatchString(pattern, s); err != nil {
+		return err // Invalid pattern
+	} else if !match {
+		return ErrInvalidNumber
+	}
+
+	return nil
+}
+
+type FileMode fs.FileMode
+
+// MarshalJSON implements json.Marshaler.
+func (fm FileMode) MarshalJSON() ([]byte, error) {
+
+	if fm > 511 {
+		// Detect wrong permissions
+		return nil, ErrInvalidPermissions
+	}
+
+	value := strconv.FormatUint(uint64(fm), 8)
+	b, err := json.Marshal(value)
+
+	l := len(b)
+	if err != nil {
+		return nil, err
+	} else if l == 5 {
+		// Prevent slice overflows in the following section
+		return b, nil
+	}
+
+	// Add leading zeros to the string
+	data := []byte(`"000"`)
+	for i, x := range b[1 : len(b)-1] {
+		j := 6 - l + i
+		data[j] = x
+	}
+
+	return []byte(data), nil
+}
+
+// UnmarshalJSON implements json.Unmarshaler.
+func (fm *FileMode) UnmarshalJSON(data []byte) (err error) {
+	var value string
+	var intVal uint64
+
+	if err = json.Unmarshal(data, &value); err != nil {
+		// probably it's an valid json
+	} else if err = validateBase(value, 8); err != nil {
+		err = ErrInvalidPermissions // Validate permissions format
+	} else if intVal, err = strconv.ParseUint(value, 8, 32); err != nil {
+		err = ErrInvalidPermissions // This should never fail
+	} else {
+		*fm = FileMode(uint32(intVal))
+	}
+
+	return
+}

api/socket/filemode_test.go

@@ -0,0 +1,94 @@
+package socket
+
+import (
+	"testing"
+)
+
+/**
+func TestBaseConversion(t *testing.T) {
+	result := baseConversion(10, 10, 8)
+	if result != uint32(12) {
+		t.Fatal("Invalid result")
+	}
+
+	result = baseConversion(20, 8, 10)
+	if result != uint32(16) {
+		t.Fatal("Invalid result")
+	}
+}
+
+func TestValidateBase(t *testing.T) {
+	err := validateBase(0, 11)
+	if err == nil {
+		t.Fatal("Must have failed")
+	}
+
+	err = validateBase(2, 2)
+	if err == nil {
+		t.Fatal("Must have failed")
+	}
+
+	err = validateBase(3, 4)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+**/
+
+func TestFileModeUnmarshal(t *testing.T) {
+	var fm FileMode
+
+	err := fm.UnmarshalJSON([]byte(`"000"`))
+	if err != nil {
+		t.Fatal(err)
+	} else if fm != 0 {
+		t.Fatal("Wrong value")
+	}
+
+	err = fm.UnmarshalJSON([]byte(`"0000"`))
+	if err == nil {
+		t.Fatal("Must have failed")
+	}
+
+	err = fm.UnmarshalJSON([]byte(`"abc"`))
+	if err == nil {
+		t.Fatal("Must have failed")
+	}
+
+	err = fm.UnmarshalJSON([]byte(`"800"`))
+	if err == nil {
+		t.Fatal("Must have failed")
+	}
+
+	err = fm.UnmarshalJSON([]byte(`"066"`))
+	if err != nil {
+		t.Fatal(err)
+	} else if fm != 54 {
+		t.Fatal("Wrong value")
+	}
+}
+
+func TestFileModeMarshal(t *testing.T) {
+	var fm FileMode
+
+	value, err := fm.MarshalJSON()
+	if err != nil {
+		t.Fatal(err)
+	} else if string(value) != `"000"` {
+		t.Fatal("Wrong value")
+	}
+
+	fm = 0600
+	value, err = fm.MarshalJSON()
+	if err != nil {
+		t.Fatal(err)
+	} else if string(value) != `"600"` {
+		t.Fatal("Wrong value")
+	}
+
+	fm = 06000
+	value, err = fm.MarshalJSON()
+	if err == nil {
+		t.Fatal("Must have failed")
+	}
+}