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db.go
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db.go
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package core
import (
"database/sql"
"errors"
"reflect"
"regexp"
"sync"
)
func MapToSlice(query string, mp interface{}) (string, []interface{}, error) {
vv := reflect.ValueOf(mp)
if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Map {
return "", []interface{}{}, ErrNoMapPointer
}
args := make([]interface{}, 0)
query = re.ReplaceAllStringFunc(query, func(src string) string {
args = append(args, vv.Elem().MapIndex(reflect.ValueOf(src[1:])).Interface())
return "?"
})
return query, args, nil
}
func StructToSlice(query string, st interface{}) (string, []interface{}, error) {
vv := reflect.ValueOf(st)
if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Struct {
return "", []interface{}{}, ErrNoStructPointer
}
args := make([]interface{}, 0)
query = re.ReplaceAllStringFunc(query, func(src string) string {
args = append(args, vv.Elem().FieldByName(src[1:]).Interface())
return "?"
})
return query, args, nil
}
type DB struct {
*sql.DB
Mapper IMapper
}
func Open(driverName, dataSourceName string) (*DB, error) {
db, err := sql.Open(driverName, dataSourceName)
return &DB{db, NewCacheMapper(&SnakeMapper{})}, err
}
func (db *DB) Query(query string, args ...interface{}) (*Rows, error) {
rows, err := db.DB.Query(query, args...)
return &Rows{rows, db.Mapper}, err
}
func (db *DB) QueryMap(query string, mp interface{}) (*Rows, error) {
query, args, err := MapToSlice(query, mp)
if err != nil {
return nil, err
}
return db.Query(query, args...)
}
func (db *DB) QueryStruct(query string, st interface{}) (*Rows, error) {
query, args, err := StructToSlice(query, st)
if err != nil {
return nil, err
}
return db.Query(query, args...)
}
type Row struct {
*sql.Row
// One of these two will be non-nil:
err error // deferred error for easy chaining
Mapper IMapper
}
func (row *Row) Scan(dest ...interface{}) error {
if row.err != nil {
return row.err
}
return row.Row.Scan(dest...)
}
func (db *DB) QueryRow(query string, args ...interface{}) *Row {
row := db.DB.QueryRow(query, args...)
return &Row{row, nil, db.Mapper}
}
func (db *DB) QueryRowMap(query string, mp interface{}) *Row {
query, args, err := MapToSlice(query, mp)
if err != nil {
return &Row{nil, err, db.Mapper}
}
return db.QueryRow(query, args...)
}
func (db *DB) QueryRowStruct(query string, st interface{}) *Row {
query, args, err := StructToSlice(query, st)
if err != nil {
return &Row{nil, err, db.Mapper}
}
return db.QueryRow(query, args...)
}
type Stmt struct {
*sql.Stmt
Mapper IMapper
names map[string]int
}
func (db *DB) Prepare(query string) (*Stmt, error) {
names := make(map[string]int)
var i int
query = re.ReplaceAllStringFunc(query, func(src string) string {
names[src[1:]] = i
i += 1
return "?"
})
stmt, err := db.DB.Prepare(query)
if err != nil {
return nil, err
}
return &Stmt{stmt, db.Mapper, names}, nil
}
func (s *Stmt) ExecMap(mp interface{}) (sql.Result, error) {
vv := reflect.ValueOf(mp)
if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Map {
return nil, errors.New("mp should be a map's pointer")
}
args := make([]interface{}, len(s.names))
for k, i := range s.names {
args[i] = vv.Elem().MapIndex(reflect.ValueOf(k)).Interface()
}
return s.Stmt.Exec(args...)
}
func (s *Stmt) ExecStruct(st interface{}) (sql.Result, error) {
vv := reflect.ValueOf(st)
if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Struct {
return nil, errors.New("mp should be a map's pointer")
}
args := make([]interface{}, len(s.names))
for k, i := range s.names {
args[i] = vv.Elem().FieldByName(k).Interface()
}
return s.Stmt.Exec(args...)
}
func (s *Stmt) Query(args ...interface{}) (*Rows, error) {
rows, err := s.Stmt.Query(args...)
if err != nil {
return nil, err
}
return &Rows{rows, s.Mapper}, nil
}
func (s *Stmt) QueryMap(mp interface{}) (*Rows, error) {
vv := reflect.ValueOf(mp)
if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Map {
return nil, errors.New("mp should be a map's pointer")
}
args := make([]interface{}, len(s.names))
for k, i := range s.names {
args[i] = vv.Elem().MapIndex(reflect.ValueOf(k)).Interface()
}
return s.Query(args...)
}
func (s *Stmt) QueryStruct(st interface{}) (*Rows, error) {
vv := reflect.ValueOf(st)
if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Struct {
return nil, errors.New("mp should be a map's pointer")
}
args := make([]interface{}, len(s.names))
for k, i := range s.names {
args[i] = vv.Elem().FieldByName(k).Interface()
}
return s.Query(args...)
}
func (s *Stmt) QueryRow(args ...interface{}) *Row {
row := s.Stmt.QueryRow(args...)
return &Row{row, nil, s.Mapper}
}
func (s *Stmt) QueryRowMap(mp interface{}) *Row {
vv := reflect.ValueOf(mp)
if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Map {
return &Row{nil, errors.New("mp should be a map's pointer"), s.Mapper}
}
args := make([]interface{}, len(s.names))
for k, i := range s.names {
args[i] = vv.Elem().MapIndex(reflect.ValueOf(k)).Interface()
}
return s.QueryRow(args...)
}
func (s *Stmt) QueryRowStruct(st interface{}) *Row {
vv := reflect.ValueOf(st)
if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Struct {
return &Row{nil, errors.New("st should be a struct's pointer"), s.Mapper}
}
args := make([]interface{}, len(s.names))
for k, i := range s.names {
args[i] = vv.Elem().FieldByName(k).Interface()
}
return s.QueryRow(args...)
}
var (
re = regexp.MustCompile(`[?](\w+)`)
)
// insert into (name) values (?)
// insert into (name) values (?name)
func (db *DB) ExecMap(query string, mp interface{}) (sql.Result, error) {
query, args, err := MapToSlice(query, mp)
if err != nil {
return nil, err
}
return db.DB.Exec(query, args...)
}
func (db *DB) ExecStruct(query string, st interface{}) (sql.Result, error) {
query, args, err := StructToSlice(query, st)
if err != nil {
return nil, err
}
return db.DB.Exec(query, args...)
}
type Rows struct {
*sql.Rows
Mapper IMapper
}
// scan data to a struct's pointer according field index
func (rs *Rows) ScanStructByIndex(dest ...interface{}) error {
if len(dest) == 0 {
return errors.New("at least one struct")
}
vvvs := make([]reflect.Value, len(dest))
for i, s := range dest {
vv := reflect.ValueOf(s)
if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Struct {
return errors.New("dest should be a struct's pointer")
}
vvvs[i] = vv.Elem()
}
cols, err := rs.Columns()
if err != nil {
return err
}
newDest := make([]interface{}, len(cols))
var i = 0
for _, vvv := range vvvs {
for j := 0; j < vvv.NumField(); j++ {
newDest[i] = vvv.Field(j).Addr().Interface()
i = i + 1
}
}
return rs.Rows.Scan(newDest...)
}
type EmptyScanner struct {
}
func (EmptyScanner) Scan(src interface{}) error {
return nil
}
var (
fieldCache = make(map[reflect.Type]map[string]int)
fieldCacheMutex sync.RWMutex
)
func fieldByName(v reflect.Value, name string) reflect.Value {
t := v.Type()
fieldCacheMutex.RLock()
cache, ok := fieldCache[t]
fieldCacheMutex.RUnlock()
if !ok {
cache = make(map[string]int)
for i := 0; i < v.NumField(); i++ {
cache[t.Field(i).Name] = i
}
fieldCacheMutex.Lock()
fieldCache[t] = cache
fieldCacheMutex.Unlock()
}
if i, ok := cache[name]; ok {
return v.Field(i)
}
return reflect.Zero(t)
}
// scan data to a struct's pointer according field name
func (rs *Rows) ScanStructByName(dest interface{}) error {
vv := reflect.ValueOf(dest)
if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Struct {
return errors.New("dest should be a struct's pointer")
}
cols, err := rs.Columns()
if err != nil {
return err
}
newDest := make([]interface{}, len(cols))
var v EmptyScanner
for j, name := range cols {
f := fieldByName(vv.Elem(), rs.Mapper.Table2Obj(name))
if f.IsValid() {
newDest[j] = f.Addr().Interface()
} else {
newDest[j] = &v
}
}
return rs.Rows.Scan(newDest...)
}
type cacheStruct struct {
value reflect.Value
idx int
}
var (
reflectCache = make(map[reflect.Type]*cacheStruct)
reflectCacheMutex sync.RWMutex
)
func ReflectNew(typ reflect.Type) reflect.Value {
reflectCacheMutex.RLock()
cs, ok := reflectCache[typ]
reflectCacheMutex.RUnlock()
const newSize = 200
if !ok || cs.idx+1 > newSize-1 {
cs = &cacheStruct{reflect.MakeSlice(reflect.SliceOf(typ), newSize, newSize), 0}
reflectCacheMutex.Lock()
reflectCache[typ] = cs
reflectCacheMutex.Unlock()
} else {
reflectCacheMutex.Lock()
cs.idx = cs.idx + 1
reflectCacheMutex.Unlock()
}
return cs.value.Index(cs.idx).Addr()
}
// scan data to a slice's pointer, slice's length should equal to columns' number
func (rs *Rows) ScanSlice(dest interface{}) error {
vv := reflect.ValueOf(dest)
if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Slice {
return errors.New("dest should be a slice's pointer")
}
vvv := vv.Elem()
cols, err := rs.Columns()
if err != nil {
return err
}
newDest := make([]interface{}, len(cols))
for j := 0; j < len(cols); j++ {
if j >= vvv.Len() {
newDest[j] = reflect.New(vvv.Type().Elem()).Interface()
} else {
newDest[j] = vvv.Index(j).Addr().Interface()
}
}
err = rs.Rows.Scan(newDest...)
if err != nil {
return err
}
srcLen := vvv.Len()
for i := srcLen; i < len(cols); i++ {
vvv = reflect.Append(vvv, reflect.ValueOf(newDest[i]).Elem())
}
return nil
}
// scan data to a map's pointer
func (rs *Rows) ScanMap(dest interface{}) error {
vv := reflect.ValueOf(dest)
if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Map {
return errors.New("dest should be a map's pointer")
}
cols, err := rs.Columns()
if err != nil {
return err
}
newDest := make([]interface{}, len(cols))
vvv := vv.Elem()
for i, _ := range cols {
newDest[i] = ReflectNew(vvv.Type().Elem()).Interface()
//v := reflect.New(vvv.Type().Elem())
//newDest[i] = v.Interface()
}
err = rs.Rows.Scan(newDest...)
if err != nil {
return err
}
for i, name := range cols {
vname := reflect.ValueOf(name)
vvv.SetMapIndex(vname, reflect.ValueOf(newDest[i]).Elem())
}
return nil
}
/*func (rs *Rows) ScanMap(dest interface{}) error {
vv := reflect.ValueOf(dest)
if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Map {
return errors.New("dest should be a map's pointer")
}
cols, err := rs.Columns()
if err != nil {
return err
}
newDest := make([]interface{}, len(cols))
err = rs.ScanSlice(newDest)
if err != nil {
return err
}
vvv := vv.Elem()
for i, name := range cols {
vname := reflect.ValueOf(name)
vvv.SetMapIndex(vname, reflect.ValueOf(newDest[i]).Elem())
}
return nil
}*/
type Tx struct {
*sql.Tx
Mapper IMapper
}
func (db *DB) Begin() (*Tx, error) {
tx, err := db.DB.Begin()
if err != nil {
return nil, err
}
return &Tx{tx, db.Mapper}, nil
}
func (tx *Tx) Prepare(query string) (*Stmt, error) {
names := make(map[string]int)
var i int
query = re.ReplaceAllStringFunc(query, func(src string) string {
names[src[1:]] = i
i += 1
return "?"
})
stmt, err := tx.Tx.Prepare(query)
if err != nil {
return nil, err
}
return &Stmt{stmt, tx.Mapper, names}, nil
}
func (tx *Tx) Stmt(stmt *Stmt) *Stmt {
// TODO:
return stmt
}
func (tx *Tx) ExecMap(query string, mp interface{}) (sql.Result, error) {
query, args, err := MapToSlice(query, mp)
if err != nil {
return nil, err
}
return tx.Tx.Exec(query, args...)
}
func (tx *Tx) ExecStruct(query string, st interface{}) (sql.Result, error) {
query, args, err := StructToSlice(query, st)
if err != nil {
return nil, err
}
return tx.Tx.Exec(query, args...)
}
func (tx *Tx) Query(query string, args ...interface{}) (*Rows, error) {
rows, err := tx.Tx.Query(query, args...)
if err != nil {
return nil, err
}
return &Rows{rows, tx.Mapper}, nil
}
func (tx *Tx) QueryMap(query string, mp interface{}) (*Rows, error) {
query, args, err := MapToSlice(query, mp)
if err != nil {
return nil, err
}
return tx.Query(query, args...)
}
func (tx *Tx) QueryStruct(query string, st interface{}) (*Rows, error) {
query, args, err := StructToSlice(query, st)
if err != nil {
return nil, err
}
return tx.Query(query, args...)
}
func (tx *Tx) QueryRow(query string, args ...interface{}) *Row {
row := tx.Tx.QueryRow(query, args...)
return &Row{row, nil, tx.Mapper}
}
func (tx *Tx) QueryRowMap(query string, mp interface{}) *Row {
query, args, err := MapToSlice(query, mp)
if err != nil {
return &Row{nil, err, tx.Mapper}
}
return tx.QueryRow(query, args...)
}
func (tx *Tx) QueryRowStruct(query string, st interface{}) *Row {
query, args, err := StructToSlice(query, st)
if err != nil {
return &Row{nil, err, tx.Mapper}
}
return tx.QueryRow(query, args...)
}