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// Copyright 2019-present Facebook Inc. All rights reserved.
// This source code is licensed under the Apache 2.0 license found
// in the LICENSE file in the root directory of this source tree.
package schema
import (
"context"
"fmt"
"github.com/facebook/ent/entc/integration/hooks/ent/hook"
"github.com/facebook/ent"
"github.com/facebook/ent/schema/edge"
"github.com/facebook/ent/schema/field"
"github.com/facebook/ent/schema/mixin"
)
// User holds the schema definition for the User entity.
type User struct {
ent.Schema
}
// Mixin of the User.
func (User) Mixin() []ent.Mixin {
return []ent.Mixin{
VersionMixin{},
}
}
// Fields of the User.
func (User) Fields() []ent.Field {
return []ent.Field{
field.String("name"),
field.Uint("worth").
Optional(),
}
}
// Edges of the User.
func (User) Edges() []ent.Edge {
return []ent.Edge{
edge.To("cards", Card.Type),
edge.To("friends", User.Type),
edge.To("best_friend", User.Type).
Unique(),
}
}
type VersionMixin struct {
mixin.Schema
}
func (VersionMixin) Fields() []ent.Field {
return []ent.Field{
field.Int("version").
Default(0),
}
}
func (VersionMixin) Hooks() []ent.Hook {
return []ent.Hook{
hook.On(VersionHook(), ent.OpUpdateOne),
}
}
func VersionHook() ent.Hook {
type OldSetVersion interface {
SetVersion(int)
Version() (int, bool)
OldVersion(context.Context) (int, error)
}
return func(next ent.Mutator) ent.Mutator {
// A hook that validates the "version" field is incremented by 1 on each update.
// Note that this is just a dummy example, and it doesn't promise consistency in
// the database.
return ent.MutateFunc(func(ctx context.Context, m ent.Mutation) (ent.Value, error) {
ver, ok := m.(OldSetVersion)
if !ok {
return next.Mutate(ctx, m)
}
oldV, err := ver.OldVersion(ctx)
if err != nil {
return nil, err
}
curV, exists := ver.Version()
if !exists {
return nil, fmt.Errorf("version field is required in update mutation")
}
if curV != oldV+1 {
return nil, fmt.Errorf("version field must be incremented by 1")
}
// Add an SQL predicate that validates the "version" column is equal
// to "oldV" (it wasn't changed during the mutation by other process).
return next.Mutate(ctx, m)
})
}
}
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