model_struct.go
package gorm
import (
"database/sql"
"errors"
"go/ast"
"reflect"
"strings"
"sync"
"time"
"github.com/jinzhu/inflection"
)
// DefaultTableNameHandler default table name handler
var DefaultTableNameHandler = func(db *DB, defaultTableName string) string {
return defaultTableName
}
// lock for mutating global cached model metadata
var structsLock sync.Mutex
// global cache of model metadata
var modelStructsMap sync.Map
// ModelStruct model definition
type ModelStruct struct {
PrimaryFields []*StructField
StructFields []*StructField
ModelType reflect.Type
defaultTableName string
l sync.Mutex
}
// TableName returns model's table name
func (s *ModelStruct) TableName(db *DB) string {
s.l.Lock()
defer s.l.Unlock()
if s.defaultTableName == "" && db != nil && s.ModelType != nil {
// Set default table name
if tabler, ok := reflect.New(s.ModelType).Interface().(tabler); ok {
s.defaultTableName = tabler.TableName()
} else {
tableName := ToTableName(s.ModelType.Name())
db.parent.RLock()
if db == nil || (db.parent != nil && !db.parent.singularTable) {
tableName = inflection.Plural(tableName)
}
db.parent.RUnlock()
s.defaultTableName = tableName
}
}
return DefaultTableNameHandler(db, s.defaultTableName)
}
// StructField model field's struct definition
type StructField struct {
DBName string
Name string
Names []string
IsPrimaryKey bool
IsNormal bool
IsIgnored bool
IsScanner bool
HasDefaultValue bool
Tag reflect.StructTag
TagSettings map[string]string
Struct reflect.StructField
IsForeignKey bool
Relationship *Relationship
tagSettingsLock sync.RWMutex
}
// TagSettingsSet Sets a tag in the tag settings map
func (sf *StructField) TagSettingsSet(key, val string) {
sf.tagSettingsLock.Lock()
defer sf.tagSettingsLock.Unlock()
sf.TagSettings[key] = val
}
// TagSettingsGet returns a tag from the tag settings
func (sf *StructField) TagSettingsGet(key string) (string, bool) {
sf.tagSettingsLock.RLock()
defer sf.tagSettingsLock.RUnlock()
val, ok := sf.TagSettings[key]
return val, ok
}
// TagSettingsDelete deletes a tag
func (sf *StructField) TagSettingsDelete(key string) {
sf.tagSettingsLock.Lock()
defer sf.tagSettingsLock.Unlock()
delete(sf.TagSettings, key)
}
func (sf *StructField) clone() *StructField {
clone := &StructField{
DBName: sf.DBName,
Name: sf.Name,
Names: sf.Names,
IsPrimaryKey: sf.IsPrimaryKey,
IsNormal: sf.IsNormal,
IsIgnored: sf.IsIgnored,
IsScanner: sf.IsScanner,
HasDefaultValue: sf.HasDefaultValue,
Tag: sf.Tag,
TagSettings: map[string]string{},
Struct: sf.Struct,
IsForeignKey: sf.IsForeignKey,
}
if sf.Relationship != nil {
relationship := *sf.Relationship
clone.Relationship = &relationship
}
// copy the struct field tagSettings, they should be read-locked while they are copied
sf.tagSettingsLock.Lock()
defer sf.tagSettingsLock.Unlock()
for key, value := range sf.TagSettings {
clone.TagSettings[key] = value
}
return clone
}
// Relationship described the relationship between models
type Relationship struct {
Kind string
PolymorphicType string
PolymorphicDBName string
PolymorphicValue string
ForeignFieldNames []string
ForeignDBNames []string
AssociationForeignFieldNames []string
AssociationForeignDBNames []string
JoinTableHandler JoinTableHandlerInterface
}
func getForeignField(column string, fields []*StructField) *StructField {
for _, field := range fields {
if field.Name == column || field.DBName == column || field.DBName == ToColumnName(column) {
return field
}
}
return nil
}
// GetModelStruct get value's model struct, relationships based on struct and tag definition
func (scope *Scope) GetModelStruct() *ModelStruct {
return scope.getModelStruct(scope, make([]*StructField, 0))
}
func (scope *Scope) getModelStruct(rootScope *Scope, allFields []*StructField) *ModelStruct {
var modelStruct ModelStruct
// Scope value can't be nil
if scope.Value == nil {
return &modelStruct
}
reflectType := reflect.ValueOf(scope.Value).Type()
for reflectType.Kind() == reflect.Slice || reflectType.Kind() == reflect.Ptr {
reflectType = reflectType.Elem()
}
// Scope value need to be a struct
if reflectType.Kind() != reflect.Struct {
return &modelStruct
}
// Get Cached model struct
isSingularTable := false
if scope.db != nil && scope.db.parent != nil {
scope.db.parent.RLock()
isSingularTable = scope.db.parent.singularTable
scope.db.parent.RUnlock()
}
hashKey := struct {
singularTable bool
reflectType reflect.Type
}{isSingularTable, reflectType}
if value, ok := modelStructsMap.Load(hashKey); ok && value != nil {
return value.(*ModelStruct)
}
modelStruct.ModelType = reflectType
// Get all fields
for i := 0; i < reflectType.NumField(); i++ {
if fieldStruct := reflectType.Field(i); ast.IsExported(fieldStruct.Name) {
field := &StructField{
Struct: fieldStruct,
Name: fieldStruct.Name,
Names: []string{fieldStruct.Name},
Tag: fieldStruct.Tag,
TagSettings: parseTagSetting(fieldStruct.Tag),
}
// is ignored field
if _, ok := field.TagSettingsGet("-"); ok {
field.IsIgnored = true
} else {
if _, ok := field.TagSettingsGet("PRIMARY_KEY"); ok {
field.IsPrimaryKey = true
modelStruct.PrimaryFields = append(modelStruct.PrimaryFields, field)
}
if _, ok := field.TagSettingsGet("DEFAULT"); ok && !field.IsPrimaryKey {
field.HasDefaultValue = true
}
if _, ok := field.TagSettingsGet("AUTO_INCREMENT"); ok && !field.IsPrimaryKey {
field.HasDefaultValue = true
}
indirectType := fieldStruct.Type
for indirectType.Kind() == reflect.Ptr {
indirectType = indirectType.Elem()
}
fieldValue := reflect.New(indirectType).Interface()
if _, isScanner := fieldValue.(sql.Scanner); isScanner {
// is scanner
field.IsScanner, field.IsNormal = true, true
if indirectType.Kind() == reflect.Struct {
for i := 0; i < indirectType.NumField(); i++ {
for key, value := range parseTagSetting(indirectType.Field(i).Tag) {
if _, ok := field.TagSettingsGet(key); !ok {
field.TagSettingsSet(key, value)
}
}
}
}
} else if _, isTime := fieldValue.(*time.Time); isTime {
// is time
field.IsNormal = true
} else if _, ok := field.TagSettingsGet("EMBEDDED"); ok || fieldStruct.Anonymous {
// is embedded struct
for _, subField := range scope.New(fieldValue).getModelStruct(rootScope, allFields).StructFields {
subField = subField.clone()
subField.Names = append([]string{fieldStruct.Name}, subField.Names...)
if prefix, ok := field.TagSettingsGet("EMBEDDED_PREFIX"); ok {
subField.DBName = prefix + subField.DBName
}
if subField.IsPrimaryKey {
if _, ok := subField.TagSettingsGet("PRIMARY_KEY"); ok {
modelStruct.PrimaryFields = append(modelStruct.PrimaryFields, subField)
} else {
subField.IsPrimaryKey = false
}
}
if subField.Relationship != nil && subField.Relationship.JoinTableHandler != nil {
if joinTableHandler, ok := subField.Relationship.JoinTableHandler.(*JoinTableHandler); ok {
newJoinTableHandler := &JoinTableHandler{}
newJoinTableHandler.Setup(subField.Relationship, joinTableHandler.TableName, reflectType, joinTableHandler.Destination.ModelType)
subField.Relationship.JoinTableHandler = newJoinTableHandler
}
}
modelStruct.StructFields = append(modelStruct.StructFields, subField)
allFields = append(allFields, subField)
}
continue
} else {
// build relationships
switch indirectType.Kind() {
case reflect.Slice:
defer func(field *StructField) {
var (
relationship = &Relationship{}
toScope = scope.New(reflect.New(field.Struct.Type).Interface())
foreignKeys []string
associationForeignKeys []string
elemType = field.Struct.Type
)
if foreignKey, _ := field.TagSettingsGet("FOREIGNKEY"); foreignKey != "" {
foreignKeys = strings.Split(foreignKey, ",")
}
if foreignKey, _ := field.TagSettingsGet("ASSOCIATION_FOREIGNKEY"); foreignKey != "" {
associationForeignKeys = strings.Split(foreignKey, ",")
} else if foreignKey, _ := field.TagSettingsGet("ASSOCIATIONFOREIGNKEY"); foreignKey != "" {
associationForeignKeys = strings.Split(foreignKey, ",")
}
for elemType.Kind() == reflect.Slice || elemType.Kind() == reflect.Ptr {
elemType = elemType.Elem()
}
if elemType.Kind() == reflect.Struct {
if many2many, _ := field.TagSettingsGet("MANY2MANY"); many2many != "" {
relationship.Kind = "many_to_many"
{ // Foreign Keys for Source
joinTableDBNames := []string{}
if foreignKey, _ := field.TagSettingsGet("JOINTABLE_FOREIGNKEY"); foreignKey != "" {
joinTableDBNames = strings.Split(foreignKey, ",")
}
// if no foreign keys defined with tag
if len(foreignKeys) == 0 {
for _, field := range modelStruct.PrimaryFields {
foreignKeys = append(foreignKeys, field.DBName)
}
}
for idx, foreignKey := range foreignKeys {
if foreignField := getForeignField(foreignKey, modelStruct.StructFields); foreignField != nil {
// source foreign keys (db names)
relationship.ForeignFieldNames = append(relationship.ForeignFieldNames, foreignField.DBName)
// setup join table foreign keys for source
if len(joinTableDBNames) > idx {
// if defined join table's foreign key
relationship.ForeignDBNames = append(relationship.ForeignDBNames, joinTableDBNames[idx])
} else {
defaultJointableForeignKey := ToColumnName(reflectType.Name()) + "_" + foreignField.DBName
relationship.ForeignDBNames = append(relationship.ForeignDBNames, defaultJointableForeignKey)
}
}
}
}
{ // Foreign Keys for Association (Destination)
associationJoinTableDBNames := []string{}
if foreignKey, _ := field.TagSettingsGet("ASSOCIATION_JOINTABLE_FOREIGNKEY"); foreignKey != "" {
associationJoinTableDBNames = strings.Split(foreignKey, ",")
}
// if no association foreign keys defined with tag
if len(associationForeignKeys) == 0 {
for _, field := range toScope.PrimaryFields() {
associationForeignKeys = append(associationForeignKeys, field.DBName)
}
}
for idx, name := range associationForeignKeys {
if field, ok := toScope.FieldByName(name); ok {
// association foreign keys (db names)
relationship.AssociationForeignFieldNames = append(relationship.AssociationForeignFieldNames, field.DBName)
// setup join table foreign keys for association
if len(associationJoinTableDBNames) > idx {
relationship.AssociationForeignDBNames = append(relationship.AssociationForeignDBNames, associationJoinTableDBNames[idx])
} else {
// join table foreign keys for association
joinTableDBName := ToColumnName(elemType.Name()) + "_" + field.DBName
relationship.AssociationForeignDBNames = append(relationship.AssociationForeignDBNames, joinTableDBName)
}
}
}
}
joinTableHandler := JoinTableHandler{}
joinTableHandler.Setup(relationship, many2many, reflectType, elemType)
relationship.JoinTableHandler = &joinTableHandler
field.Relationship = relationship
} else {
// User has many comments, associationType is User, comment use UserID as foreign key
var associationType = reflectType.Name()
var toFields = toScope.GetStructFields()
relationship.Kind = "has_many"
if polymorphic, _ := field.TagSettingsGet("POLYMORPHIC"); polymorphic != "" {
// Dog has many toys, tag polymorphic is Owner, then associationType is Owner
// Toy use OwnerID, OwnerType ('dogs') as foreign key
if polymorphicType := getForeignField(polymorphic+"Type", toFields); polymorphicType != nil {
associationType = polymorphic
relationship.PolymorphicType = polymorphicType.Name
relationship.PolymorphicDBName = polymorphicType.DBName
// if Dog has multiple set of toys set name of the set (instead of default 'dogs')
if value, ok := field.TagSettingsGet("POLYMORPHIC_VALUE"); ok {
relationship.PolymorphicValue = value
} else {
relationship.PolymorphicValue = scope.TableName()
}
polymorphicType.IsForeignKey = true
}
}
// if no foreign keys defined with tag
if len(foreignKeys) == 0 {
// if no association foreign keys defined with tag
if len(associationForeignKeys) == 0 {
for _, field := range modelStruct.PrimaryFields {
foreignKeys = append(foreignKeys, associationType+field.Name)
associationForeignKeys = append(associationForeignKeys, field.Name)
}
} else {
// generate foreign keys from defined association foreign keys
for _, scopeFieldName := range associationForeignKeys {
if foreignField := getForeignField(scopeFieldName, allFields); foreignField != nil {
foreignKeys = append(foreignKeys, associationType+foreignField.Name)
associationForeignKeys = append(associationForeignKeys, foreignField.Name)
}
}
}
} else {
// generate association foreign keys from foreign keys
if len(associationForeignKeys) == 0 {
for _, foreignKey := range foreignKeys {
if strings.HasPrefix(foreignKey, associationType) {
associationForeignKey := strings.TrimPrefix(foreignKey, associationType)
if foreignField := getForeignField(associationForeignKey, allFields); foreignField != nil {
associationForeignKeys = append(associationForeignKeys, associationForeignKey)
}
}
}
if len(associationForeignKeys) == 0 && len(foreignKeys) == 1 {
associationForeignKeys = []string{rootScope.PrimaryKey()}
}
} else if len(foreignKeys) != len(associationForeignKeys) {
scope.Err(errors.New("invalid foreign keys, should have same length"))
return
}
}
for idx, foreignKey := range foreignKeys {
if foreignField := getForeignField(foreignKey, toFields); foreignField != nil {
if associationField := getForeignField(associationForeignKeys[idx], allFields); associationField != nil {
// mark field as foreignkey, use global lock to avoid race
structsLock.Lock()
foreignField.IsForeignKey = true
structsLock.Unlock()
// association foreign keys
relationship.AssociationForeignFieldNames = append(relationship.AssociationForeignFieldNames, associationField.Name)
relationship.AssociationForeignDBNames = append(relationship.AssociationForeignDBNames, associationField.DBName)
// association foreign keys
relationship.ForeignFieldNames = append(relationship.ForeignFieldNames, foreignField.Name)
relationship.ForeignDBNames = append(relationship.ForeignDBNames, foreignField.DBName)
}
}
}
if len(relationship.ForeignFieldNames) != 0 {
field.Relationship = relationship
}
}
} else {
field.IsNormal = true
}
}(field)
case reflect.Struct:
defer func(field *StructField) {
var (
// user has one profile, associationType is User, profile use UserID as foreign key
// user belongs to profile, associationType is Profile, user use ProfileID as foreign key
associationType = reflectType.Name()
relationship = &Relationship{}
toScope = scope.New(reflect.New(field.Struct.Type).Interface())
toFields = toScope.GetStructFields()
tagForeignKeys []string
tagAssociationForeignKeys []string
)
if foreignKey, _ := field.TagSettingsGet("FOREIGNKEY"); foreignKey != "" {
tagForeignKeys = strings.Split(foreignKey, ",")
}
if foreignKey, _ := field.TagSettingsGet("ASSOCIATION_FOREIGNKEY"); foreignKey != "" {
tagAssociationForeignKeys = strings.Split(foreignKey, ",")
} else if foreignKey, _ := field.TagSettingsGet("ASSOCIATIONFOREIGNKEY"); foreignKey != "" {
tagAssociationForeignKeys = strings.Split(foreignKey, ",")
}
if polymorphic, _ := field.TagSettingsGet("POLYMORPHIC"); polymorphic != "" {
// Cat has one toy, tag polymorphic is Owner, then associationType is Owner
// Toy use OwnerID, OwnerType ('cats') as foreign key
if polymorphicType := getForeignField(polymorphic+"Type", toFields); polymorphicType != nil {
associationType = polymorphic
relationship.PolymorphicType = polymorphicType.Name
relationship.PolymorphicDBName = polymorphicType.DBName
// if Cat has several different types of toys set name for each (instead of default 'cats')
if value, ok := field.TagSettingsGet("POLYMORPHIC_VALUE"); ok {
relationship.PolymorphicValue = value
} else {
relationship.PolymorphicValue = scope.TableName()
}
polymorphicType.IsForeignKey = true
}
}
// Has One
{
var foreignKeys = tagForeignKeys
var associationForeignKeys = tagAssociationForeignKeys
// if no foreign keys defined with tag
if len(foreignKeys) == 0 {
// if no association foreign keys defined with tag
if len(associationForeignKeys) == 0 {
for _, primaryField := range modelStruct.PrimaryFields {
foreignKeys = append(foreignKeys, associationType+primaryField.Name)
associationForeignKeys = append(associationForeignKeys, primaryField.Name)
}
} else {
// generate foreign keys form association foreign keys
for _, associationForeignKey := range tagAssociationForeignKeys {
if foreignField := getForeignField(associationForeignKey, allFields); foreignField != nil {
foreignKeys = append(foreignKeys, associationType+foreignField.Name)
associationForeignKeys = append(associationForeignKeys, foreignField.Name)
}
}
}
} else {
// generate association foreign keys from foreign keys
if len(associationForeignKeys) == 0 {
for _, foreignKey := range foreignKeys {
if strings.HasPrefix(foreignKey, associationType) {
associationForeignKey := strings.TrimPrefix(foreignKey, associationType)
if foreignField := getForeignField(associationForeignKey, allFields); foreignField != nil {
associationForeignKeys = append(associationForeignKeys, associationForeignKey)
}
}
}
if len(associationForeignKeys) == 0 && len(foreignKeys) == 1 {
associationForeignKeys = []string{rootScope.PrimaryKey()}
}
} else if len(foreignKeys) != len(associationForeignKeys) {
scope.Err(errors.New("invalid foreign keys, should have same length"))
return
}
}
for idx, foreignKey := range foreignKeys {
if foreignField := getForeignField(foreignKey, toFields); foreignField != nil {
if scopeField := getForeignField(associationForeignKeys[idx], allFields); scopeField != nil {
// mark field as foreignkey, use global lock to avoid race
structsLock.Lock()
foreignField.IsForeignKey = true
structsLock.Unlock()
// association foreign keys
relationship.AssociationForeignFieldNames = append(relationship.AssociationForeignFieldNames, scopeField.Name)
relationship.AssociationForeignDBNames = append(relationship.AssociationForeignDBNames, scopeField.DBName)
// association foreign keys
relationship.ForeignFieldNames = append(relationship.ForeignFieldNames, foreignField.Name)
relationship.ForeignDBNames = append(relationship.ForeignDBNames, foreignField.DBName)
}
}
}
}
if len(relationship.ForeignFieldNames) != 0 {
relationship.Kind = "has_one"
field.Relationship = relationship
} else {
var foreignKeys = tagForeignKeys
var associationForeignKeys = tagAssociationForeignKeys
if len(foreignKeys) == 0 {
// generate foreign keys & association foreign keys
if len(associationForeignKeys) == 0 {
for _, primaryField := range toScope.PrimaryFields() {
foreignKeys = append(foreignKeys, field.Name+primaryField.Name)
associationForeignKeys = append(associationForeignKeys, primaryField.Name)
}
} else {
// generate foreign keys with association foreign keys
for _, associationForeignKey := range associationForeignKeys {
if foreignField := getForeignField(associationForeignKey, toFields); foreignField != nil {
foreignKeys = append(foreignKeys, field.Name+foreignField.Name)
associationForeignKeys = append(associationForeignKeys, foreignField.Name)
}
}
}
} else {
// generate foreign keys & association foreign keys
if len(associationForeignKeys) == 0 {
for _, foreignKey := range foreignKeys {
if strings.HasPrefix(foreignKey, field.Name) {
associationForeignKey := strings.TrimPrefix(foreignKey, field.Name)
if foreignField := getForeignField(associationForeignKey, toFields); foreignField != nil {
associationForeignKeys = append(associationForeignKeys, associationForeignKey)
}
}
}
if len(associationForeignKeys) == 0 && len(foreignKeys) == 1 {
associationForeignKeys = []string{toScope.PrimaryKey()}
}
} else if len(foreignKeys) != len(associationForeignKeys) {
scope.Err(errors.New("invalid foreign keys, should have same length"))
return
}
}
for idx, foreignKey := range foreignKeys {
if foreignField := getForeignField(foreignKey, modelStruct.StructFields); foreignField != nil {
if associationField := getForeignField(associationForeignKeys[idx], toFields); associationField != nil {
// mark field as foreignkey, use global lock to avoid race
structsLock.Lock()
foreignField.IsForeignKey = true
structsLock.Unlock()
// association foreign keys
relationship.AssociationForeignFieldNames = append(relationship.AssociationForeignFieldNames, associationField.Name)
relationship.AssociationForeignDBNames = append(relationship.AssociationForeignDBNames, associationField.DBName)
// source foreign keys
relationship.ForeignFieldNames = append(relationship.ForeignFieldNames, foreignField.Name)
relationship.ForeignDBNames = append(relationship.ForeignDBNames, foreignField.DBName)
}
}
}
if len(relationship.ForeignFieldNames) != 0 {
relationship.Kind = "belongs_to"
field.Relationship = relationship
}
}
}(field)
default:
field.IsNormal = true
}
}
}
// Even it is ignored, also possible to decode db value into the field
if value, ok := field.TagSettingsGet("COLUMN"); ok {
field.DBName = value
} else {
field.DBName = ToColumnName(fieldStruct.Name)
}
modelStruct.StructFields = append(modelStruct.StructFields, field)
allFields = append(allFields, field)
}
}
if len(modelStruct.PrimaryFields) == 0 {
if field := getForeignField("id", modelStruct.StructFields); field != nil {
field.IsPrimaryKey = true
modelStruct.PrimaryFields = append(modelStruct.PrimaryFields, field)
}
}
modelStructsMap.Store(hashKey, &modelStruct)
return &modelStruct
}
// GetStructFields get model's field structs
func (scope *Scope) GetStructFields() (fields []*StructField) {
return scope.GetModelStruct().StructFields
}
func parseTagSetting(tags reflect.StructTag) map[string]string {
setting := map[string]string{}
for _, str := range []string{tags.Get("sql"), tags.Get("gorm")} {
if str == "" {
continue
}
tags := strings.Split(str, ";")
for _, value := range tags {
v := strings.Split(value, ":")
k := strings.TrimSpace(strings.ToUpper(v[0]))
if len(v) >= 2 {
setting[k] = strings.Join(v[1:], ":")
} else {
setting[k] = k
}
}
}
return setting
}