// Map receives a pointer to map or struct and maps it to columns and values.
func Map(item interface{}, options *MapOptions) ([]string, []interface{}, error) {
var fv fieldValue
if options == nil {
options = &defaultMapOptions
}
itemV := reflect.ValueOf(item)
if !itemV.IsValid() {
return nil, nil, nil
}
itemT := itemV.Type()
if itemT.Kind() == reflect.Ptr {
// Single dereference. Just in case the user passes a pointer to struct
// instead of a struct.
item = itemV.Elem().Interface()
itemV = reflect.ValueOf(item)
itemT = itemV.Type()
}
switch itemT.Kind() {
case reflect.Struct:
fieldMap := mapper.TypeMap(itemT).Names
nfields := len(fieldMap)
fv.values = make([]interface{}, 0, nfields)
fv.fields = make([]string, 0, nfields)
for _, fi := range fieldMap {
// Field options
_, tagOmitEmpty := fi.Options["omitempty"]
_, tagStringArray := fi.Options["stringarray"]
_, tagInt64Array := fi.Options["int64array"]
_, tagJSONB := fi.Options["jsonb"]
fld := reflectx.FieldByIndexesReadOnly(itemV, fi.Index)
if fld.Kind() == reflect.Ptr && fld.IsNil() {
if options.IncludeNil || !tagOmitEmpty {
fv.fields = append(fv.fields, fi.Name)
fv.values = append(fv.values, fld.Interface())
}
continue
}
var value interface{}
switch {
case tagStringArray:
v, ok := fld.Interface().([]string)
if !ok {
return nil, nil, fmt.Errorf(`Expecting field %q to be []string (using "stringarray" tag)`, fi.Name)
}
value = stringArray(v)
case tagInt64Array:
v, ok := fld.Interface().([]int64)
if !ok {
return nil, nil, fmt.Errorf(`Expecting field %q to be []int64 (using "int64array" tag)`, fi.Name)
}
value = int64Array(v)
case tagJSONB:
value = jsonbType{fld.Interface()}
default:
value = fld.Interface()
}
if !options.IncludeZeroed {
if tagOmitEmpty {
if t, ok := fld.Interface().(hasIsZero); ok {
if t.IsZero() {
continue
}
} else if fld.Kind() == reflect.Array || fld.Kind() == reflect.Slice {
if value == nil {
continue
}
} else if value == fi.Zero.Interface() {
continue
}
}
}
fv.fields = append(fv.fields, fi.Name)
v, err := marshal(value)
if err != nil {
return nil, nil, err
}
fv.values = append(fv.values, v)
}
case reflect.Map:
nfields := itemV.Len()
fv.values = make([]interface{}, nfields)
fv.fields = make([]string, nfields)
mkeys := itemV.MapKeys()
for i, keyV := range mkeys {
valv := itemV.MapIndex(keyV)
fv.fields[i] = fmt.Sprintf("%v", keyV.Interface())
v, err := marshal(valv.Interface())
if err != nil {
return nil, nil, err
}
fv.values[i] = v
}
default:
return nil, nil, ErrExpectingPointerToEitherMapOrStruct
}
if len(fv.fields) == 0 {
return nil, nil, errors.New("No values mapped.")
}
sort.Sort(&fv)
return fv.fields, fv.values, nil
}
func fetchResult(itemT reflect.Type, rows *sql.Rows, columns []string) (reflect.Value, error) {
var item reflect.Value
var err error
objT := itemT
switch objT.Kind() {
case reflect.Map:
item = reflect.MakeMap(objT)
case reflect.Struct:
item = reflect.New(objT)
case reflect.Ptr:
objT = itemT.Elem()
if objT.Kind() != reflect.Struct {
return item, ErrExpectingMapOrStruct
}
item = reflect.New(objT)
default:
return item, ErrExpectingMapOrStruct
}
switch objT.Kind() {
case reflect.Struct:
values := make([]interface{}, len(columns))
typeMap := mapper.TypeMap(itemT)
fieldMap := typeMap.Names
wrappedValues := map[*reflectx.FieldInfo]interface{}{}
for i, k := range columns {
fi, ok := fieldMap[k]
if !ok {
values[i] = new(interface{})
continue
}
// TODO: refactor into a nice pattern
if _, ok := fi.Options["stringarray"]; ok {
values[i] = &[]byte{}
wrappedValues[fi] = values[i]
} else if _, ok := fi.Options["int64array"]; ok {
values[i] = &[]byte{}
wrappedValues[fi] = values[i]
} else if _, ok := fi.Options["jsonb"]; ok {
values[i] = &[]byte{}
wrappedValues[fi] = values[i]
} else {
f := reflectx.FieldByIndexes(item, fi.Index)
values[i] = f.Addr().Interface()
}
if u, ok := values[i].(db.Unmarshaler); ok {
values[i] = scanner{u}
}
}
// Scanner - for reads
// Valuer - for writes
// OptionTypes
// - before/after scan
// - before/after valuer..
if err = rows.Scan(values...); err != nil {
return item, err
}
// TODO: move this stuff out of here.. find a nice pattern
for fi, v := range wrappedValues {
var opt string
if _, ok := fi.Options["stringarray"]; ok {
opt = "stringarray"
} else if _, ok := fi.Options["int64array"]; ok {
opt = "int64array"
} else if _, ok := fi.Options["jsonb"]; ok {
opt = "jsonb"
}
b := v.(*[]byte)
f := reflectx.FieldByIndexesReadOnly(item, fi.Index)
switch opt {
case "stringarray":
v := stringArray{}
err := v.Scan(*b)
if err != nil {
return item, err
}
f.Set(reflect.ValueOf(v))
case "int64array":
v := int64Array{}
err := v.Scan(*b)
if err != nil {
return item, err
}
f.Set(reflect.ValueOf(v))
case "jsonb":
if len(*b) == 0 {
continue
}
var vv reflect.Value
t := reflect.PtrTo(f.Type())
switch t.Kind() {
case reflect.Map:
vv = reflect.MakeMap(t)
case reflect.Slice:
vv = reflect.MakeSlice(t, 0, 0)
default:
vv = reflect.New(t)
}
err := json.Unmarshal(*b, vv.Interface())
if err != nil {
return item, err
}
vv = vv.Elem().Elem()
if !vv.IsValid() || (vv.Kind() == reflect.Ptr && vv.IsNil()) {
continue
}
f.Set(vv)
}
}
case reflect.Map:
columns, err := rows.Columns()
if err != nil {
return item, err
}
values := make([]interface{}, len(columns))
for i := range values {
if itemT.Elem().Kind() == reflect.Interface {
values[i] = new(interface{})
} else {
values[i] = reflect.New(itemT.Elem()).Interface()
}
}
if err = rows.Scan(values...); err != nil {
return item, err
}
for i, column := range columns {
item.SetMapIndex(reflect.ValueOf(column), reflect.Indirect(reflect.ValueOf(values[i])))
}
}
return item, nil
}