Refacotr Preload

callbacks/preload.go

@@ -9,102 +9,6 @@ import (
 	"github.com/jinzhu/gorm/utils"
 )
 
-// getRelationsValue get relations's value from a reflect value
-func getRelationsValue(reflectValue reflect.Value, rels []*schema.Relationship) (reflectResults reflect.Value) {
-	for _, rel := range rels {
-		reflectResults = reflect.MakeSlice(reflect.SliceOf(rel.FieldSchema.ModelType), 0, 0)
-
-		appendToResults := func(value reflect.Value) {
-			if _, isZero := rel.Field.ValueOf(value); !isZero {
-				result := reflect.Indirect(rel.Field.ReflectValueOf(value))
-				switch result.Kind() {
-				case reflect.Struct:
-					reflectResults = reflect.Append(reflectResults, result)
-				case reflect.Slice, reflect.Array:
-					for i := 0; i < value.Len(); i++ {
-						reflectResults = reflect.Append(reflectResults, reflect.Indirect(value.Index(i)))
-					}
-				}
-			}
-		}
-
-		switch reflectValue.Kind() {
-		case reflect.Struct:
-			appendToResults(reflectValue)
-		case reflect.Slice:
-			for i := 0; i < reflectValue.Len(); i++ {
-				appendToResults(reflectValue.Index(i))
-			}
-		}
-
-		reflectValue = reflectResults
-	}
-
-	return
-}
-
-func getIdentityFieldValuesMap(reflectValue reflect.Value, fields []*schema.Field) (map[string][]reflect.Value, [][]interface{}) {
-	var (
-		fieldValues = make([]reflect.Value, len(fields))
-		results     = [][]interface{}{}
-		dataResults = map[string][]reflect.Value{}
-	)
-
-	switch reflectValue.Kind() {
-	case reflect.Struct:
-		results = [][]interface{}{make([]interface{}, len(fields))}
-
-		for idx, field := range fields {
-			fieldValues[idx] = field.ReflectValueOf(reflectValue)
-			results[0][idx] = fieldValues[idx].Interface()
-		}
-
-		dataResults[utils.ToStringKey(fieldValues...)] = []reflect.Value{reflectValue}
-	case reflect.Slice, reflect.Array:
-		for i := 0; i < reflectValue.Len(); i++ {
-			for idx, field := range fields {
-				fieldValues[idx] = field.ReflectValueOf(reflectValue.Index(i))
-			}
-
-			dataKey := utils.ToStringKey(fieldValues...)
-			if _, ok := dataResults[dataKey]; !ok {
-				result := make([]interface{}, len(fieldValues))
-				for idx, fieldValue := range fieldValues {
-					result[idx] = fieldValue.Interface()
-				}
-				results = append(results, result)
-
-				dataResults[dataKey] = []reflect.Value{reflectValue.Index(i)}
-			} else {
-				dataResults[dataKey] = append(dataResults[dataKey], reflectValue.Index(i))
-			}
-		}
-	}
-
-	return dataResults, results
-}
-
-func preloadData(tx *gorm.DB, resultSchema *schema.Schema, foreignKeys []string, foreignValues [][]interface{}, conds []interface{}) reflect.Value {
-	slice := reflect.MakeSlice(reflect.SliceOf(resultSchema.ModelType), 0, 0)
-	results := reflect.New(slice.Type())
-	results.Elem().Set(slice)
-
-	queryValues := make([]interface{}, len(foreignValues))
-	if len(foreignKeys) == 1 {
-		for idx, r := range foreignValues {
-			queryValues[idx] = r[0]
-		}
-		tx.Where(clause.IN{Column: foreignKeys[0], Values: queryValues}).Find(results.Interface(), conds...)
-	} else {
-		for idx, r := range foreignValues {
-			queryValues[idx] = r
-		}
-		tx.Where(clause.IN{Column: foreignKeys, Values: queryValues}).Find(results.Interface(), conds...)
-	}
-
-	return results.Elem()
-}
-
 func preload(db *gorm.DB, rels []*schema.Relationship, conds []interface{}) {
 	var (
 		reflectValue     = db.Statement.ReflectValue
@@ -118,7 +22,7 @@ func preload(db *gorm.DB, rels []*schema.Relationship, conds []interface{}) {
 	)
 
 	if len(rels) > 1 {
-		reflectValue = getRelationsValue(reflectValue, rels[:len(rels)])
+		reflectValue = schema.GetRelationsValues(reflectValue, rels[:len(rels)])
 	}
 
 	if rel.JoinTable != nil {
@@ -138,8 +42,11 @@ func preload(db *gorm.DB, rels []*schema.Relationship, conds []interface{}) {
 			}
 		}
 
-		joinIdentityMap, joinForeignValues := getIdentityFieldValuesMap(reflectValue, joinForeignFields)
+		joinIdentityMap, joinForeignValues := schema.GetIdentityFieldValuesMap(reflectValue, joinForeignFields)
-		joinResults := preloadData(tx, rel.JoinTable, joinForeignKeys, joinForeignValues, nil)
+
+		joinResults := rel.JoinTable.MakeSlice().Elem()
+		column, values := schema.ToQueryValues(joinForeignKeys, joinForeignValues)
+		tx.Where(clause.IN{Column: column, Values: values}).Find(joinResults.Addr().Interface())
 
 		// convert join identity map to relation identity map
 		fieldValues := make([]reflect.Value, len(foreignFields))
@@ -158,7 +65,7 @@ func preload(db *gorm.DB, rels []*schema.Relationship, conds []interface{}) {
 			}
 		}
 
-		_, foreignValues = getIdentityFieldValuesMap(joinResults, joinRelForeignFields)
+		_, foreignValues = schema.GetIdentityFieldValuesMap(joinResults, joinRelForeignFields)
 	} else {
 		for _, ref := range rel.References {
 			if ref.OwnPrimaryKey {
@@ -174,10 +81,12 @@ func preload(db *gorm.DB, rels []*schema.Relationship, conds []interface{}) {
 			}
 		}
 
-		identityMap, foreignValues = getIdentityFieldValuesMap(reflectValue, foreignFields)
+		identityMap, foreignValues = schema.GetIdentityFieldValuesMap(reflectValue, foreignFields)
 	}
 
-	reflectResults := preloadData(tx, rel.FieldSchema, relForeignKeys, foreignValues, conds)
+	reflectResults := rel.FieldSchema.MakeSlice().Elem()
+	column, values := schema.ToQueryValues(relForeignKeys, foreignValues)
+	tx.Where(clause.IN{Column: column, Values: values}).Find(reflectResults.Addr().Interface(), conds...)
 
 	fieldValues := make([]reflect.Value, len(foreignFields))
 	for i := 0; i < reflectResults.Len(); i++ {

schema/schema.go

@@ -43,6 +43,13 @@ func (schema Schema) String() string {
 	return fmt.Sprintf("%v.%v", schema.ModelType.PkgPath(), schema.ModelType.Name())
 }
 
+func (schema Schema) MakeSlice() reflect.Value {
+	slice := reflect.MakeSlice(reflect.SliceOf(schema.ModelType), 0, 0)
+	results := reflect.New(slice.Type())
+	results.Elem().Set(slice)
+	return results
+}
+
 func (schema Schema) LookUpField(name string) *Field {
 	if field, ok := schema.FieldsByDBName[name]; ok {
 		return field

schema/utils.go

@@ -4,6 +4,8 @@ import (
 	"reflect"
 	"regexp"
 	"strings"
+
+	"github.com/jinzhu/gorm/utils"
 )
 
 func ParseTagSetting(str string, sep string) map[string]string {
@@ -49,3 +51,96 @@ func toColumns(val string) (results []string) {
 func removeSettingFromTag(tag reflect.StructTag, name string) reflect.StructTag {
 	return reflect.StructTag(regexp.MustCompile(`(?i)(gorm:.*?)(`+name+`:.*?)(;|("))`).ReplaceAllString(string(tag), "${1}${4}"))
 }
+
+// GetRelationsValues get relations's values from a reflect value
+func GetRelationsValues(reflectValue reflect.Value, rels []*Relationship) (reflectResults reflect.Value) {
+	for _, rel := range rels {
+		reflectResults = reflect.MakeSlice(reflect.SliceOf(rel.FieldSchema.ModelType), 0, 0)
+
+		appendToResults := func(value reflect.Value) {
+			if _, isZero := rel.Field.ValueOf(value); !isZero {
+				result := reflect.Indirect(rel.Field.ReflectValueOf(value))
+				switch result.Kind() {
+				case reflect.Struct:
+					reflectResults = reflect.Append(reflectResults, result)
+				case reflect.Slice, reflect.Array:
+					for i := 0; i < value.Len(); i++ {
+						reflectResults = reflect.Append(reflectResults, reflect.Indirect(value.Index(i)))
+					}
+				}
+			}
+		}
+
+		switch reflectValue.Kind() {
+		case reflect.Struct:
+			appendToResults(reflectValue)
+		case reflect.Slice:
+			for i := 0; i < reflectValue.Len(); i++ {
+				appendToResults(reflectValue.Index(i))
+			}
+		}
+
+		reflectValue = reflectResults
+	}
+
+	return
+}
+
+// GetIdentityFieldValuesMap get identity map from fields
+func GetIdentityFieldValuesMap(reflectValue reflect.Value, fields []*Field) (map[string][]reflect.Value, [][]interface{}) {
+	var (
+		fieldValues = make([]reflect.Value, len(fields))
+		results     = [][]interface{}{}
+		dataResults = map[string][]reflect.Value{}
+	)
+
+	switch reflectValue.Kind() {
+	case reflect.Struct:
+		results = [][]interface{}{make([]interface{}, len(fields))}
+
+		for idx, field := range fields {
+			fieldValues[idx] = field.ReflectValueOf(reflectValue)
+			results[0][idx] = fieldValues[idx].Interface()
+		}
+
+		dataResults[utils.ToStringKey(fieldValues...)] = []reflect.Value{reflectValue}
+	case reflect.Slice, reflect.Array:
+		for i := 0; i < reflectValue.Len(); i++ {
+			for idx, field := range fields {
+				fieldValues[idx] = field.ReflectValueOf(reflectValue.Index(i))
+			}
+
+			dataKey := utils.ToStringKey(fieldValues...)
+			if _, ok := dataResults[dataKey]; !ok {
+				result := make([]interface{}, len(fieldValues))
+				for idx, fieldValue := range fieldValues {
+					result[idx] = fieldValue.Interface()
+				}
+				results = append(results, result)
+
+				dataResults[dataKey] = []reflect.Value{reflectValue.Index(i)}
+			} else {
+				dataResults[dataKey] = append(dataResults[dataKey], reflectValue.Index(i))
+			}
+		}
+	}
+
+	return dataResults, results
+}
+
+// ToQueryValues to query values
+func ToQueryValues(foreignKeys []string, foreignValues [][]interface{}) (interface{}, []interface{}) {
+	queryValues := make([]interface{}, len(foreignValues))
+	if len(foreignKeys) == 1 {
+		for idx, r := range foreignValues {
+			queryValues[idx] = r[0]
+		}
+
+		return foreignKeys[0], queryValues
+	} else {
+		for idx, r := range foreignValues {
+			queryValues[idx] = r
+		}
+	}
+	return foreignKeys, queryValues
+}