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// Copyright 2012 Gary Burd
//
// Licensed under the Apache License, Version 2.0 (the "License"): you may
// not use this file except in compliance with the License. You may obtain
// a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations
// under the License.
package redis
import (
"errors"
"fmt"
"reflect"
"strconv"
"strings"
"sync"
)
func ensureLen(d reflect.Value, n int) {
if n > d.Cap() {
d.Set(reflect.MakeSlice(d.Type(), n, n))
} else {
d.SetLen(n)
}
}
func cannotConvert(d reflect.Value, s interface{}) error {
var sname string
switch s.(type) {
case string:
sname = "Redis simple string"
case Error:
sname = "Redis error"
case int64:
sname = "Redis integer"
case []byte:
sname = "Redis bulk string"
case []interface{}:
sname = "Redis array"
default:
sname = reflect.TypeOf(s).String()
}
return fmt.Errorf("cannot convert from %s to %s", sname, d.Type())
}
func convertAssignBulkString(d reflect.Value, s []byte) (err error) {
switch d.Type().Kind() {
case reflect.Float32, reflect.Float64:
var x float64
x, err = strconv.ParseFloat(string(s), d.Type().Bits())
d.SetFloat(x)
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
var x int64
x, err = strconv.ParseInt(string(s), 10, d.Type().Bits())
d.SetInt(x)
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
var x uint64
x, err = strconv.ParseUint(string(s), 10, d.Type().Bits())
d.SetUint(x)
case reflect.Bool:
var x bool
x, err = strconv.ParseBool(string(s))
d.SetBool(x)
case reflect.String:
d.SetString(string(s))
case reflect.Slice:
if d.Type().Elem().Kind() != reflect.Uint8 {
err = cannotConvert(d, s)
} else {
d.SetBytes(s)
}
default:
err = cannotConvert(d, s)
}
return
}
func convertAssignInt(d reflect.Value, s int64) (err error) {
switch d.Type().Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
d.SetInt(s)
if d.Int() != s {
err = strconv.ErrRange
d.SetInt(0)
}
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
if s < 0 {
err = strconv.ErrRange
} else {
x := uint64(s)
d.SetUint(x)
if d.Uint() != x {
err = strconv.ErrRange
d.SetUint(0)
}
}
case reflect.Bool:
d.SetBool(s != 0)
default:
err = cannotConvert(d, s)
}
return
}
func convertAssignValue(d reflect.Value, s interface{}) (err error) {
if d.Kind() != reflect.Ptr {
if d.CanAddr() {
d2 := d.Addr()
if d2.CanInterface() {
if scanner, ok := d2.Interface().(Scanner); ok {
return scanner.RedisScan(s)
}
}
}
} else if d.CanInterface() {
// Already a reflect.Ptr
if d.IsNil() {
d.Set(reflect.New(d.Type().Elem()))
}
if scanner, ok := d.Interface().(Scanner); ok {
return scanner.RedisScan(s)
}
}
switch s := s.(type) {
case []byte:
err = convertAssignBulkString(d, s)
case int64:
err = convertAssignInt(d, s)
default:
err = cannotConvert(d, s)
}
return err
}
func convertAssignArray(d reflect.Value, s []interface{}) error {
if d.Type().Kind() != reflect.Slice {
return cannotConvert(d, s)
}
ensureLen(d, len(s))
for i := 0; i < len(s); i++ {
if err := convertAssignValue(d.Index(i), s[i]); err != nil {
return err
}
}
return nil
}
func convertAssign(d interface{}, s interface{}) (err error) {
if scanner, ok := d.(Scanner); ok {
return scanner.RedisScan(s)
}
// Handle the most common destination types using type switches and
// fall back to reflection for all other types.
switch s := s.(type) {
case nil:
// ignore
case []byte:
switch d := d.(type) {
case *string:
*d = string(s)
case *int:
*d, err = strconv.Atoi(string(s))
case *bool:
*d, err = strconv.ParseBool(string(s))
case *[]byte:
*d = s
case *interface{}:
*d = s
case nil:
// skip value
default:
if d := reflect.ValueOf(d); d.Type().Kind() != reflect.Ptr {
err = cannotConvert(d, s)
} else {
err = convertAssignBulkString(d.Elem(), s)
}
}
case int64:
switch d := d.(type) {
case *int:
x := int(s)
if int64(x) != s {
err = strconv.ErrRange
x = 0
}
*d = x
case *bool:
*d = s != 0
case *interface{}:
*d = s
case nil:
// skip value
default:
if d := reflect.ValueOf(d); d.Type().Kind() != reflect.Ptr {
err = cannotConvert(d, s)
} else {
err = convertAssignInt(d.Elem(), s)
}
}
case string:
switch d := d.(type) {
case *string:
*d = s
case *interface{}:
*d = s
case nil:
// skip value
default:
err = cannotConvert(reflect.ValueOf(d), s)
}
case []interface{}:
switch d := d.(type) {
case *[]interface{}:
*d = s
case *interface{}:
*d = s
case nil:
// skip value
default:
if d := reflect.ValueOf(d); d.Type().Kind() != reflect.Ptr {
err = cannotConvert(d, s)
} else {
err = convertAssignArray(d.Elem(), s)
}
}
case Error:
err = s
default:
err = cannotConvert(reflect.ValueOf(d), s)
}
return
}
// Scan copies from src to the values pointed at by dest.
//
// Scan uses RedisScan if available otherwise:
//
// The values pointed at by dest must be an integer, float, boolean, string,
// []byte, interface{} or slices of these types. Scan uses the standard strconv
// package to convert bulk strings to numeric and boolean types.
//
// If a dest value is nil, then the corresponding src value is skipped.
//
// If a src element is nil, then the corresponding dest value is not modified.
//
// To enable easy use of Scan in a loop, Scan returns the slice of src
// following the copied values.
func Scan(src []interface{}, dest ...interface{}) ([]interface{}, error) {
if len(src) < len(dest) {
return nil, errors.New("redigo.Scan: array short")
}
var err error
for i, d := range dest {
err = convertAssign(d, src[i])
if err != nil {
err = fmt.Errorf("redigo.Scan: cannot assign to dest %d: %v", i, err)
break
}
}
return src[len(dest):], err
}
type fieldSpec struct {
name string
index []int
omitEmpty bool
}
type structSpec struct {
m map[string]*fieldSpec
l []*fieldSpec
}
func (ss *structSpec) fieldSpec(name []byte) *fieldSpec {
return ss.m[string(name)]
}
func compileStructSpec(t reflect.Type, depth map[string]int, index []int, ss *structSpec) {
for i := 0; i < t.NumField(); i++ {
f := t.Field(i)
switch {
case f.PkgPath != "" && !f.Anonymous:
// Ignore unexported fields.
case f.Anonymous:
// TODO: Handle pointers. Requires change to decoder and
// protection against infinite recursion.
if f.Type.Kind() == reflect.Struct {
compileStructSpec(f.Type, depth, append(index, i), ss)
}
default:
fs := &fieldSpec{name: f.Name}
tag := f.Tag.Get("redis")
p := strings.Split(tag, ",")
if len(p) > 0 {
if p[0] == "-" {
continue
}
if len(p[0]) > 0 {
fs.name = p[0]
}
for _, s := range p[1:] {
switch s {
case "omitempty":
fs.omitEmpty = true
default:
panic(fmt.Errorf("redigo: unknown field tag %s for type %s", s, t.Name()))
}
}
}
d, found := depth[fs.name]
if !found {
d = 1 << 30
}
switch {
case len(index) == d:
// At same depth, remove from result.
delete(ss.m, fs.name)
j := 0
for i := 0; i < len(ss.l); i++ {
if fs.name != ss.l[i].name {
ss.l[j] = ss.l[i]
j += 1
}
}
ss.l = ss.l[:j]
case len(index) < d:
fs.index = make([]int, len(index)+1)
copy(fs.index, index)
fs.index[len(index)] = i
depth[fs.name] = len(index)
ss.m[fs.name] = fs
ss.l = append(ss.l, fs)
}
}
}
}
var (
structSpecMutex sync.RWMutex
structSpecCache = make(map[reflect.Type]*structSpec)
defaultFieldSpec = &fieldSpec{}
)
func structSpecForType(t reflect.Type) *structSpec {
structSpecMutex.RLock()
ss, found := structSpecCache[t]
structSpecMutex.RUnlock()
if found {
return ss
}
structSpecMutex.Lock()
defer structSpecMutex.Unlock()
ss, found = structSpecCache[t]
if found {
return ss
}
ss = &structSpec{m: make(map[string]*fieldSpec)}
compileStructSpec(t, make(map[string]int), nil, ss)
structSpecCache[t] = ss
return ss
}
var errScanStructValue = errors.New("redigo.ScanStruct: value must be non-nil pointer to a struct")
// ScanStruct scans alternating names and values from src to a struct. The
// HGETALL and CONFIG GET commands return replies in this format.
//
// ScanStruct uses exported field names to match values in the response. Use
// 'redis' field tag to override the name:
//
// Field int `redis:"myName"`
//
// Fields with the tag redis:"-" are ignored.
//
// Each field uses RedisScan if available otherwise:
// Integer, float, boolean, string and []byte fields are supported. Scan uses the
// standard strconv package to convert bulk string values to numeric and
// boolean types.
//
// If a src element is nil, then the corresponding field is not modified.
func ScanStruct(src []interface{}, dest interface{}) error {
d := reflect.ValueOf(dest)
if d.Kind() != reflect.Ptr || d.IsNil() {
return errScanStructValue
}
d = d.Elem()
if d.Kind() != reflect.Struct {
return errScanStructValue
}
ss := structSpecForType(d.Type())
if len(src)%2 != 0 {
return errors.New("redigo.ScanStruct: number of values not a multiple of 2")
}
for i := 0; i < len(src); i += 2 {
s := src[i+1]
if s == nil {
continue
}
name, ok := src[i].([]byte)
if !ok {
return fmt.Errorf("redigo.ScanStruct: key %d not a bulk string value", i)
}
fs := ss.fieldSpec(name)
if fs == nil {
continue
}
if err := convertAssignValue(d.FieldByIndex(fs.index), s); err != nil {
return fmt.Errorf("redigo.ScanStruct: cannot assign field %s: %v", fs.name, err)
}
}
return nil
}
var (
errScanSliceValue = errors.New("redigo.ScanSlice: dest must be non-nil pointer to a struct")
)
// ScanSlice scans src to the slice pointed to by dest. The elements the dest
// slice must be integer, float, boolean, string, struct or pointer to struct
// values.
//
// Struct fields must be integer, float, boolean or string values. All struct
// fields are used unless a subset is specified using fieldNames.
func ScanSlice(src []interface{}, dest interface{}, fieldNames ...string) error {
d := reflect.ValueOf(dest)
if d.Kind() != reflect.Ptr || d.IsNil() {
return errScanSliceValue
}
d = d.Elem()
if d.Kind() != reflect.Slice {
return errScanSliceValue
}
isPtr := false
t := d.Type().Elem()
if t.Kind() == reflect.Ptr && t.Elem().Kind() == reflect.Struct {
isPtr = true
t = t.Elem()
}
if t.Kind() != reflect.Struct {
ensureLen(d, len(src))
for i, s := range src {
if s == nil {
continue
}
if err := convertAssignValue(d.Index(i), s); err != nil {
return fmt.Errorf("redigo.ScanSlice: cannot assign element %d: %v", i, err)
}
}
return nil
}
ss := structSpecForType(t)
fss := ss.l
if len(fieldNames) > 0 {
fss = make([]*fieldSpec, len(fieldNames))
for i, name := range fieldNames {
fss[i] = ss.m[name]
if fss[i] == nil {
return fmt.Errorf("redigo.ScanSlice: ScanSlice bad field name %s", name)
}
}
}
if len(fss) == 0 {
return errors.New("redigo.ScanSlice: no struct fields")
}
n := len(src) / len(fss)
if n*len(fss) != len(src) {
return errors.New("redigo.ScanSlice: length not a multiple of struct field count")
}
ensureLen(d, n)
for i := 0; i < n; i++ {
d := d.Index(i)
if isPtr {
if d.IsNil() {
d.Set(reflect.New(t))
}
d = d.Elem()
}
for j, fs := range fss {
s := src[i*len(fss)+j]
if s == nil {
continue
}
if err := convertAssignValue(d.FieldByIndex(fs.index), s); err != nil {
return fmt.Errorf("redigo.ScanSlice: cannot assign element %d to field %s: %v", i*len(fss)+j, fs.name, err)
}
}
}
return nil
}
// Args is a helper for constructing command arguments from structured values.
type Args []interface{}
// Add returns the result of appending value to args.
func (args Args) Add(value ...interface{}) Args {
return append(args, value...)
}
// AddFlat returns the result of appending the flattened value of v to args.
//
// Maps are flattened by appending the alternating keys and map values to args.
//
// Slices are flattened by appending the slice elements to args.
//
// Structs are flattened by appending the alternating names and values of
// exported fields to args. If v is a nil struct pointer, then nothing is
// appended. The 'redis' field tag overrides struct field names. See ScanStruct
// for more information on the use of the 'redis' field tag.
//
// Other types are appended to args as is.
func (args Args) AddFlat(v interface{}) Args {
rv := reflect.ValueOf(v)
switch rv.Kind() {
case reflect.Struct:
args = flattenStruct(args, rv)
case reflect.Slice:
for i := 0; i < rv.Len(); i++ {
args = append(args, rv.Index(i).Interface())
}
case reflect.Map:
for _, k := range rv.MapKeys() {
args = append(args, k.Interface(), rv.MapIndex(k).Interface())
}
case reflect.Ptr:
if rv.Type().Elem().Kind() == reflect.Struct {
if !rv.IsNil() {
args = flattenStruct(args, rv.Elem())
}
} else {
args = append(args, v)
}
default:
args = append(args, v)
}
return args
}
func flattenStruct(args Args, v reflect.Value) Args {
ss := structSpecForType(v.Type())
for _, fs := range ss.l {
fv := v.FieldByIndex(fs.index)
if fs.omitEmpty {
var empty = false
switch fv.Kind() {
case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
empty = fv.Len() == 0
case reflect.Bool:
empty = !fv.Bool()
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
empty = fv.Int() == 0
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
empty = fv.Uint() == 0
case reflect.Float32, reflect.Float64:
empty = fv.Float() == 0
case reflect.Interface, reflect.Ptr:
empty = fv.IsNil()
}
if empty {
continue
}
}
args = append(args, fs.name, fv.Interface())
}
return args
}