Merge pull request #36 from neuronlabs/develop

Added `OrderedFields`

Author: kucjac

mapping/structfield.go

@@ -3,6 +3,7 @@ package mapping
 import (
 	"net/url"
 	"reflect"
+	"sort"
 	"strings"
 
 	"github.com/neuronlabs/errors"
@@ -701,3 +702,46 @@ func (f FieldKind) String() string {
 	}
 	return "Unknown"
 }
+
+var _ sort.Interface = OrderedFields{}
+
+// OrderedFields is the wrapper over the slice of struct fields that allows to keep the fields
+// in an ordered sorting. The sorts is based on the fields index.
+type OrderedFields []*StructField
+
+// Insert inserts the field into an ordered fields slice. In order to insert the field
+// a pointer to ordered fields must be used.
+func (o *OrderedFields) Insert(field *StructField) {
+	for i, in := range *o {
+		if !o.less(in, field) {
+			(*o) = append((*o)[:i], append([]*StructField{field}, (*o)[i:]...)...)
+			break
+		}
+	}
+}
+
+// Len implements sort.Interface interface.
+func (o OrderedFields) Len() int {
+	return len(o)
+}
+
+// Less implements sort.Interface interface.
+func (o OrderedFields) Less(i, j int) bool {
+	return o.less(o[i], o[j])
+}
+
+// Swap implements sort.Interface interface.
+func (o OrderedFields) Swap(i, j int) {
+	o[i], o[j] = o[j], o[i]
+}
+
+func (o OrderedFields) less(first, second *StructField) bool {
+	var result bool
+	for k := 0; k < len(first.fieldIndex); k++ {
+		if first.fieldIndex[k] != second.fieldIndex[k] {
+			result = first.fieldIndex[k] < second.fieldIndex[k]
+			break
+		}
+	}
+	return result
+}

mapping/structfield_test.go

@@ -0,0 +1,77 @@
+package mapping
+
+import (
+	"sort"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// TestOrderedFields tests the ordered fields methods.
+func TestOrderedFields(t *testing.T) {
+	type Model struct {
+		ID     int
+		Name   string
+		First  string
+		Second int
+		Third  string
+	}
+	mm := testingModelMap(t)
+
+	err := mm.RegisterModels(Model{})
+	require.NoError(t, err)
+
+	m, err := mm.GetModelStruct(Model{})
+	require.NoError(t, err)
+
+	fields := m.Fields()
+
+	// unsort the slice
+	fields[0], fields[3], fields[2], fields[4] = fields[3], fields[0], fields[4], fields[2]
+
+	// Remove the 'Name' field at index [1]
+	fields = append(fields[:1], fields[2:]...)
+
+	ordered := OrderedFields(fields)
+	// sort the fields
+	sort.Sort(ordered)
+
+	for i, field := range ordered {
+		switch i {
+		case 0:
+			assert.Equal(t, "ID", field.Name())
+		case 1:
+			assert.Equal(t, "First", field.Name())
+		case 2:
+			assert.Equal(t, "Second", field.Name())
+		case 3:
+			assert.Equal(t, "Third", field.Name())
+		}
+	}
+
+	// insert back the name field
+	nameField, ok := m.Attribute("Name")
+	require.True(t, ok)
+
+	orderedPtr := &ordered
+	orderedPtr.Insert(nameField)
+
+	assert.Len(t, ordered, 5)
+
+	for i, field := range ordered {
+		switch i {
+		case 0:
+			assert.Equal(t, "ID", field.Name())
+		case 1:
+			assert.Equal(t, "Name", field.Name())
+		case 2:
+			assert.Equal(t, "First", field.Name())
+		case 3:
+			assert.Equal(t, "Second", field.Name())
+		case 4:
+			assert.Equal(t, "Third", field.Name())
+		}
+	}
+
+}

query/scope-fieldset.go

@@ -2,6 +2,7 @@ package query
 
 import (
 	"reflect"
+	"sort"
 
 	"github.com/neuronlabs/errors"
 
@@ -10,6 +11,18 @@ import (
 	"github.com/neuronlabs/neuron-core/mapping"
 )
 
+// OrderedFieldset gets the fieldset fields sorted by the struct field's index.
+func (s *Scope) OrderedFieldset() (ordered mapping.OrderedFields) {
+	var i int
+	ordered = mapping.OrderedFields(make([]*mapping.StructField, len(s.Fieldset)))
+	for _, field := range s.Fieldset {
+		ordered[i] = field
+		i++
+	}
+	sort.Sort(ordered)
+	return ordered
+}
+
 // InFieldset checks if the provided field is in the scope's fieldset.
 func (s *Scope) InFieldset(field interface{}) (*mapping.StructField, bool) {
 	switch fv := field.(type) {

query/scope-fieldset_test.go

@@ -0,0 +1,63 @@
+package query
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// TestOrderedFielset test the ordered fieldset function.
+func TestOrderedFielset(t *testing.T) {
+	type Ordered struct {
+		ID     int
+		First  string
+		Second string
+		Third  string
+	}
+
+	c := newController(t)
+	err := c.RegisterModels(Ordered{})
+	require.NoError(t, err)
+
+	t.Run("All", func(t *testing.T) {
+		s, err := NewC(c, &Ordered{})
+		require.NoError(t, err)
+
+		s.setAllFields()
+
+		ordered := s.OrderedFieldset()
+		for i, field := range ordered {
+			switch i {
+			case 0:
+				assert.Equal(t, "ID", field.Name())
+			case 1:
+				assert.Equal(t, "First", field.Name())
+			case 2:
+				assert.Equal(t, "Second", field.Name())
+			case 3:
+				assert.Equal(t, "Third", field.Name())
+			}
+		}
+	})
+
+	t.Run("Custom", func(t *testing.T) {
+		s, err := NewC(c, &Ordered{})
+		require.NoError(t, err)
+
+		err = s.SetFields("first", "id", "third")
+		require.NoError(t, err)
+
+		ordered := s.OrderedFieldset()
+		for i, field := range ordered {
+			switch i {
+			case 0:
+				assert.Equal(t, "ID", field.Name())
+			case 1:
+				assert.Equal(t, "First", field.Name())
+			case 2:
+				assert.Equal(t, "Third", field.Name())
+			}
+		}
+	})
+}