soft_delete.go

// MIT License
//
// Copyright (c) 2020 Lack
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

package dao

import (
	"database/sql"
	"database/sql/driver"
	"encoding/json"
	"reflect"

	"github.com/lack-io/vine/lib/dao/clause"
	"github.com/lack-io/vine/lib/dao/schema"
)

type DeletedAt sql.NullTime

// Scan implements the Scanner interface.
func (n *DeletedAt) Scan(value interface{}) error {
	return (*sql.NullTime)(n).Scan(value)
}

// Value implements the driver Valuer interface.
func (n DeletedAt) Value() (driver.Value, error) {
	if !n.Valid {
		return nil, nil
	}
	return n.Time, nil
}

func (n DeletedAt) MarshalJSON() ([]byte, error) {
	if n.Valid {
		return json.Marshal(n.Time)
	}
	return json.Marshal(nil)
}

func (n *DeletedAt) UnmarshalJSON(b []byte) error {
	if string(b) == "null" {
		n.Valid = false
		return nil
	}
	err := json.Unmarshal(b, &n.Time)
	if err == nil {
		n.Valid = true
	}
	return err
}

func (DeletedAt) QueryClauses(f *schema.Field) []clause.Interface {
	return []clause.Interface{SoftDeleteQueryClause{Field: f}}
}

type SoftDeleteQueryClause struct {
	Field *schema.Field
}

func (sd SoftDeleteQueryClause) Name() string {
	return ""
}

func (sd SoftDeleteQueryClause) Build(clause.Builder) {
}

func (sd SoftDeleteQueryClause) MergeClause(*clause.Clause) {
}

func (sd SoftDeleteQueryClause) ModifyStatement(stmt *Statement) {
	if _, ok := stmt.Clauses["soft_delete_enabled"]; !ok {
		if c, ok := stmt.Clauses["WHERE"]; ok {
			if where, ok := c.Expression.(clause.Where); ok && len(where.Exprs) > 1 {
				for _, expr := range where.Exprs {
					if orCond, ok := expr.(clause.OrConditions); ok && len(orCond.Exprs) == 1 {
						where.Exprs = []clause.Expression{clause.And(where.Exprs...)}
						c.Expression = where
						stmt.Clauses["WHERE"] = c
						break
					}
				}
			}
		}

		stmt.AddClause(clause.Where{Exprs: []clause.Expression{
			clause.Eq{Column: clause.Column{Table: clause.CurrentTable, Name: sd.Field.DBName}, Value: nil},
		}})
		stmt.Clauses["soft_delete_enabled"] = clause.Clause{}
	}
}

func (DeletedAt) DeleteClauses(f *schema.Field) []clause.Interface {
	return []clause.Interface{SoftDeleteDeleteClause{Field: f}}
}

type SoftDeleteDeleteClause struct {
	Field *schema.Field
}

func (sd SoftDeleteDeleteClause) Name() string {
	return ""
}

func (sd SoftDeleteDeleteClause) Build(clause.Builder) {
}

func (sd SoftDeleteDeleteClause) MergeClause(*clause.Clause) {
}

func (sd SoftDeleteDeleteClause) ModifyStatement(stmt *Statement) {
	if stmt.SQL.String() == "" {
		curTime := stmt.DB.NowFunc()
		stmt.AddClause(clause.Set{{Column: clause.Column{Name: sd.Field.DBName}, Value: curTime}})
		stmt.SetColumn(sd.Field.DBName, curTime, true)

		if stmt.Schema != nil {
			_, queryValues := schema.GetIdentityFieldValuesMap(stmt.ReflectValue, stmt.Schema.PrimaryFields)
			column, values := schema.ToQueryValues(stmt.Table, stmt.Schema.PrimaryFieldDBNames, queryValues)

			if len(values) > 0 {
				stmt.AddClause(clause.Where{Exprs: []clause.Expression{clause.IN{Column: column, Values: values}}})
			}

			if stmt.ReflectValue.CanAddr() && stmt.Dest != stmt.Model && stmt.Model != nil {
				_, queryValues = schema.GetIdentityFieldValuesMap(reflect.ValueOf(stmt.Model), stmt.Schema.PrimaryFields)
				column, values = schema.ToQueryValues(stmt.Table, stmt.Schema.PrimaryFieldDBNames, queryValues)

				if len(values) > 0 {
					stmt.AddClause(clause.Where{Exprs: []clause.Expression{clause.IN{Column: column, Values: values}}})
				}
			}
		}

		if _, ok := stmt.Clauses["WHERE"]; !stmt.DB.AllowGlobalUpdate && !ok {
			stmt.DB.AddError(ErrMissingWhereClause)
		} else {
			SoftDeleteQueryClause{Field: sd.Field}.ModifyStatement(stmt)
		}

		stmt.AddClauseIfNotExists(clause.Update{})
		stmt.Build("UPDATE", "SET", "WHERE")
	}
}