Permalink
5bf1611 Dec 20, 2016
@cbandy @mjibson
757 lines (655 sloc) 17.2 KB
package pq
import (
"bytes"
"database/sql"
"database/sql/driver"
"encoding/hex"
"fmt"
"reflect"
"strconv"
"strings"
)
var typeByteSlice = reflect.TypeOf([]byte{})
var typeDriverValuer = reflect.TypeOf((*driver.Valuer)(nil)).Elem()
var typeSqlScanner = reflect.TypeOf((*sql.Scanner)(nil)).Elem()
// Array returns the optimal driver.Valuer and sql.Scanner for an array or
// slice of any dimension.
//
// For example:
// db.Query(`SELECT * FROM t WHERE id = ANY($1)`, pq.Array([]int{235, 401}))
//
// var x []sql.NullInt64
// db.QueryRow('SELECT ARRAY[235, 401]').Scan(pq.Array(&x))
//
// Scanning multi-dimensional arrays is not supported. Arrays where the lower
// bound is not one (such as `[0:0]={1}') are not supported.
func Array(a interface{}) interface {
driver.Valuer
sql.Scanner
} {
switch a := a.(type) {
case []bool:
return (*BoolArray)(&a)
case []float64:
return (*Float64Array)(&a)
case []int64:
return (*Int64Array)(&a)
case []string:
return (*StringArray)(&a)
case *[]bool:
return (*BoolArray)(a)
case *[]float64:
return (*Float64Array)(a)
case *[]int64:
return (*Int64Array)(a)
case *[]string:
return (*StringArray)(a)
}
return GenericArray{a}
}
// ArrayDelimiter may be optionally implemented by driver.Valuer or sql.Scanner
// to override the array delimiter used by GenericArray.
type ArrayDelimiter interface {
// ArrayDelimiter returns the delimiter character(s) for this element's type.
ArrayDelimiter() string
}
// BoolArray represents a one-dimensional array of the PostgreSQL boolean type.
type BoolArray []bool
// Scan implements the sql.Scanner interface.
func (a *BoolArray) Scan(src interface{}) error {
switch src := src.(type) {
case []byte:
return a.scanBytes(src)
case string:
return a.scanBytes([]byte(src))
case nil:
*a = nil
return nil
}
return fmt.Errorf("pq: cannot convert %T to BoolArray", src)
}
func (a *BoolArray) scanBytes(src []byte) error {
elems, err := scanLinearArray(src, []byte{','}, "BoolArray")
if err != nil {
return err
}
if *a != nil && len(elems) == 0 {
*a = (*a)[:0]
} else {
b := make(BoolArray, len(elems))
for i, v := range elems {
if len(v) != 1 {
return fmt.Errorf("pq: could not parse boolean array index %d: invalid boolean %q", i, v)
}
switch v[0] {
case 't':
b[i] = true
case 'f':
b[i] = false
default:
return fmt.Errorf("pq: could not parse boolean array index %d: invalid boolean %q", i, v)
}
}
*a = b
}
return nil
}
// Value implements the driver.Valuer interface.
func (a BoolArray) Value() (driver.Value, error) {
if a == nil {
return nil, nil
}
if n := len(a); n > 0 {
// There will be exactly two curly brackets, N bytes of values,
// and N-1 bytes of delimiters.
b := make([]byte, 1+2*n)
for i := 0; i < n; i++ {
b[2*i] = ','
if a[i] {
b[1+2*i] = 't'
} else {
b[1+2*i] = 'f'
}
}
b[0] = '{'
b[2*n] = '}'
return string(b), nil
}
return "{}", nil
}
// ByteaArray represents a one-dimensional array of the PostgreSQL bytea type.
type ByteaArray [][]byte
// Scan implements the sql.Scanner interface.
func (a *ByteaArray) Scan(src interface{}) error {
switch src := src.(type) {
case []byte:
return a.scanBytes(src)
case string:
return a.scanBytes([]byte(src))
case nil:
*a = nil
return nil
}
return fmt.Errorf("pq: cannot convert %T to ByteaArray", src)
}
func (a *ByteaArray) scanBytes(src []byte) error {
elems, err := scanLinearArray(src, []byte{','}, "ByteaArray")
if err != nil {
return err
}
if *a != nil && len(elems) == 0 {
*a = (*a)[:0]
} else {
b := make(ByteaArray, len(elems))
for i, v := range elems {
b[i], err = parseBytea(v)
if err != nil {
return fmt.Errorf("could not parse bytea array index %d: %s", i, err.Error())
}
}
*a = b
}
return nil
}
// Value implements the driver.Valuer interface. It uses the "hex" format which
// is only supported on PostgreSQL 9.0 or newer.
func (a ByteaArray) Value() (driver.Value, error) {
if a == nil {
return nil, nil
}
if n := len(a); n > 0 {
// There will be at least two curly brackets, 2*N bytes of quotes,
// 3*N bytes of hex formatting, and N-1 bytes of delimiters.
size := 1 + 6*n
for _, x := range a {
size += hex.EncodedLen(len(x))
}
b := make([]byte, size)
for i, s := 0, b; i < n; i++ {
o := copy(s, `,"\\x`)
o += hex.Encode(s[o:], a[i])
s[o] = '"'
s = s[o+1:]
}
b[0] = '{'
b[size-1] = '}'
return string(b), nil
}
return "{}", nil
}
// Float64Array represents a one-dimensional array of the PostgreSQL double
// precision type.
type Float64Array []float64
// Scan implements the sql.Scanner interface.
func (a *Float64Array) Scan(src interface{}) error {
switch src := src.(type) {
case []byte:
return a.scanBytes(src)
case string:
return a.scanBytes([]byte(src))
case nil:
*a = nil
return nil
}
return fmt.Errorf("pq: cannot convert %T to Float64Array", src)
}
func (a *Float64Array) scanBytes(src []byte) error {
elems, err := scanLinearArray(src, []byte{','}, "Float64Array")
if err != nil {
return err
}
if *a != nil && len(elems) == 0 {
*a = (*a)[:0]
} else {
b := make(Float64Array, len(elems))
for i, v := range elems {
if b[i], err = strconv.ParseFloat(string(v), 64); err != nil {
return fmt.Errorf("pq: parsing array element index %d: %v", i, err)
}
}
*a = b
}
return nil
}
// Value implements the driver.Valuer interface.
func (a Float64Array) Value() (driver.Value, error) {
if a == nil {
return nil, nil
}
if n := len(a); n > 0 {
// There will be at least two curly brackets, N bytes of values,
// and N-1 bytes of delimiters.
b := make([]byte, 1, 1+2*n)
b[0] = '{'
b = strconv.AppendFloat(b, a[0], 'f', -1, 64)
for i := 1; i < n; i++ {
b = append(b, ',')
b = strconv.AppendFloat(b, a[i], 'f', -1, 64)
}
return string(append(b, '}')), nil
}
return "{}", nil
}
// GenericArray implements the driver.Valuer and sql.Scanner interfaces for
// an array or slice of any dimension.
type GenericArray struct{ A interface{} }
func (GenericArray) evaluateDestination(rt reflect.Type) (reflect.Type, func([]byte, reflect.Value) error, string) {
var assign func([]byte, reflect.Value) error
var del = ","
// TODO calculate the assign function for other types
// TODO repeat this section on the element type of arrays or slices (multidimensional)
{
if reflect.PtrTo(rt).Implements(typeSqlScanner) {
// dest is always addressable because it is an element of a slice.
assign = func(src []byte, dest reflect.Value) (err error) {
ss := dest.Addr().Interface().(sql.Scanner)
if src == nil {
err = ss.Scan(nil)
} else {
err = ss.Scan(src)
}
return
}
goto FoundType
}
assign = func([]byte, reflect.Value) error {
return fmt.Errorf("pq: scanning to %s is not implemented; only sql.Scanner", rt)
}
}
FoundType:
if ad, ok := reflect.Zero(rt).Interface().(ArrayDelimiter); ok {
del = ad.ArrayDelimiter()
}
return rt, assign, del
}
// Scan implements the sql.Scanner interface.
func (a GenericArray) Scan(src interface{}) error {
dpv := reflect.ValueOf(a.A)
switch {
case dpv.Kind() != reflect.Ptr:
return fmt.Errorf("pq: destination %T is not a pointer to array or slice", a.A)
case dpv.IsNil():
return fmt.Errorf("pq: destination %T is nil", a.A)
}
dv := dpv.Elem()
switch dv.Kind() {
case reflect.Slice:
case reflect.Array:
default:
return fmt.Errorf("pq: destination %T is not a pointer to array or slice", a.A)
}
switch src := src.(type) {
case []byte:
return a.scanBytes(src, dv)
case string:
return a.scanBytes([]byte(src), dv)
case nil:
if dv.Kind() == reflect.Slice {
dv.Set(reflect.Zero(dv.Type()))
return nil
}
}
return fmt.Errorf("pq: cannot convert %T to %s", src, dv.Type())
}
func (a GenericArray) scanBytes(src []byte, dv reflect.Value) error {
dtype, assign, del := a.evaluateDestination(dv.Type().Elem())
dims, elems, err := parseArray(src, []byte(del))
if err != nil {
return err
}
// TODO allow multidimensional
if len(dims) > 1 {
return fmt.Errorf("pq: scanning from multidimensional ARRAY%s is not implemented",
strings.Replace(fmt.Sprint(dims), " ", "][", -1))
}
// Treat a zero-dimensional array like an array with a single dimension of zero.
if len(dims) == 0 {
dims = append(dims, 0)
}
for i, rt := 0, dv.Type(); i < len(dims); i, rt = i+1, rt.Elem() {
switch rt.Kind() {
case reflect.Slice:
case reflect.Array:
if rt.Len() != dims[i] {
return fmt.Errorf("pq: cannot convert ARRAY%s to %s",
strings.Replace(fmt.Sprint(dims), " ", "][", -1), dv.Type())
}
default:
// TODO handle multidimensional
}
}
values := reflect.MakeSlice(reflect.SliceOf(dtype), len(elems), len(elems))
for i, e := range elems {
if err := assign(e, values.Index(i)); err != nil {
return fmt.Errorf("pq: parsing array element index %d: %v", i, err)
}
}
// TODO handle multidimensional
switch dv.Kind() {
case reflect.Slice:
dv.Set(values.Slice(0, dims[0]))
case reflect.Array:
for i := 0; i < dims[0]; i++ {
dv.Index(i).Set(values.Index(i))
}
}
return nil
}
// Value implements the driver.Valuer interface.
func (a GenericArray) Value() (driver.Value, error) {
if a.A == nil {
return nil, nil
}
rv := reflect.ValueOf(a.A)
switch rv.Kind() {
case reflect.Slice:
if rv.IsNil() {
return nil, nil
}
case reflect.Array:
default:
return nil, fmt.Errorf("pq: Unable to convert %T to array", a.A)
}
if n := rv.Len(); n > 0 {
// There will be at least two curly brackets, N bytes of values,
// and N-1 bytes of delimiters.
b := make([]byte, 0, 1+2*n)
b, _, err := appendArray(b, rv, n)
return string(b), err
}
return "{}", nil
}
// Int64Array represents a one-dimensional array of the PostgreSQL integer types.
type Int64Array []int64
// Scan implements the sql.Scanner interface.
func (a *Int64Array) Scan(src interface{}) error {
switch src := src.(type) {
case []byte:
return a.scanBytes(src)
case string:
return a.scanBytes([]byte(src))
case nil:
*a = nil
return nil
}
return fmt.Errorf("pq: cannot convert %T to Int64Array", src)
}
func (a *Int64Array) scanBytes(src []byte) error {
elems, err := scanLinearArray(src, []byte{','}, "Int64Array")
if err != nil {
return err
}
if *a != nil && len(elems) == 0 {
*a = (*a)[:0]
} else {
b := make(Int64Array, len(elems))
for i, v := range elems {
if b[i], err = strconv.ParseInt(string(v), 10, 64); err != nil {
return fmt.Errorf("pq: parsing array element index %d: %v", i, err)
}
}
*a = b
}
return nil
}
// Value implements the driver.Valuer interface.
func (a Int64Array) Value() (driver.Value, error) {
if a == nil {
return nil, nil
}
if n := len(a); n > 0 {
// There will be at least two curly brackets, N bytes of values,
// and N-1 bytes of delimiters.
b := make([]byte, 1, 1+2*n)
b[0] = '{'
b = strconv.AppendInt(b, a[0], 10)
for i := 1; i < n; i++ {
b = append(b, ',')
b = strconv.AppendInt(b, a[i], 10)
}
return string(append(b, '}')), nil
}
return "{}", nil
}
// StringArray represents a one-dimensional array of the PostgreSQL character types.
type StringArray []string
// Scan implements the sql.Scanner interface.
func (a *StringArray) Scan(src interface{}) error {
switch src := src.(type) {
case []byte:
return a.scanBytes(src)
case string:
return a.scanBytes([]byte(src))
case nil:
*a = nil
return nil
}
return fmt.Errorf("pq: cannot convert %T to StringArray", src)
}
func (a *StringArray) scanBytes(src []byte) error {
elems, err := scanLinearArray(src, []byte{','}, "StringArray")
if err != nil {
return err
}
if *a != nil && len(elems) == 0 {
*a = (*a)[:0]
} else {
b := make(StringArray, len(elems))
for i, v := range elems {
if b[i] = string(v); v == nil {
return fmt.Errorf("pq: parsing array element index %d: cannot convert nil to string", i)
}
}
*a = b
}
return nil
}
// Value implements the driver.Valuer interface.
func (a StringArray) Value() (driver.Value, error) {
if a == nil {
return nil, nil
}
if n := len(a); n > 0 {
// There will be at least two curly brackets, 2*N bytes of quotes,
// and N-1 bytes of delimiters.
b := make([]byte, 1, 1+3*n)
b[0] = '{'
b = appendArrayQuotedBytes(b, []byte(a[0]))
for i := 1; i < n; i++ {
b = append(b, ',')
b = appendArrayQuotedBytes(b, []byte(a[i]))
}
return string(append(b, '}')), nil
}
return "{}", nil
}
// appendArray appends rv to the buffer, returning the extended buffer and
// the delimiter used between elements.
//
// It panics when n <= 0 or rv's Kind is not reflect.Array nor reflect.Slice.
func appendArray(b []byte, rv reflect.Value, n int) ([]byte, string, error) {
var del string
var err error
b = append(b, '{')
if b, del, err = appendArrayElement(b, rv.Index(0)); err != nil {
return b, del, err
}
for i := 1; i < n; i++ {
b = append(b, del...)
if b, del, err = appendArrayElement(b, rv.Index(i)); err != nil {
return b, del, err
}
}
return append(b, '}'), del, nil
}
// appendArrayElement appends rv to the buffer, returning the extended buffer
// and the delimiter to use before the next element.
//
// When rv's Kind is neither reflect.Array nor reflect.Slice, it is converted
// using driver.DefaultParameterConverter and the resulting []byte or string
// is double-quoted.
//
// See http://www.postgresql.org/docs/current/static/arrays.html#ARRAYS-IO
func appendArrayElement(b []byte, rv reflect.Value) ([]byte, string, error) {
if k := rv.Kind(); k == reflect.Array || k == reflect.Slice {
if t := rv.Type(); t != typeByteSlice && !t.Implements(typeDriverValuer) {
if n := rv.Len(); n > 0 {
return appendArray(b, rv, n)
}
return b, "", nil
}
}
var del string = ","
var err error
var iv interface{} = rv.Interface()
if ad, ok := iv.(ArrayDelimiter); ok {
del = ad.ArrayDelimiter()
}
if iv, err = driver.DefaultParameterConverter.ConvertValue(iv); err != nil {
return b, del, err
}
switch v := iv.(type) {
case nil:
return append(b, "NULL"...), del, nil
case []byte:
return appendArrayQuotedBytes(b, v), del, nil
case string:
return appendArrayQuotedBytes(b, []byte(v)), del, nil
}
b, err = appendValue(b, iv)
return b, del, err
}
func appendArrayQuotedBytes(b, v []byte) []byte {
b = append(b, '"')
for {
i := bytes.IndexAny(v, `"\`)
if i < 0 {
b = append(b, v...)
break
}
if i > 0 {
b = append(b, v[:i]...)
}
b = append(b, '\\', v[i])
v = v[i+1:]
}
return append(b, '"')
}
func appendValue(b []byte, v driver.Value) ([]byte, error) {
return append(b, encode(nil, v, 0)...), nil
}
// parseArray extracts the dimensions and elements of an array represented in
// text format. Only representations emitted by the backend are supported.
// Notably, whitespace around brackets and delimiters is significant, and NULL
// is case-sensitive.
//
// See http://www.postgresql.org/docs/current/static/arrays.html#ARRAYS-IO
func parseArray(src, del []byte) (dims []int, elems [][]byte, err error) {
var depth, i int
if len(src) < 1 || src[0] != '{' {
return nil, nil, fmt.Errorf("pq: unable to parse array; expected %q at offset %d", '{', 0)
}
Open:
for i < len(src) {
switch src[i] {
case '{':
depth++
i++
case '}':
elems = make([][]byte, 0)
goto Close
default:
break Open
}
}
dims = make([]int, i)
Element:
for i < len(src) {
switch src[i] {
case '{':
if depth == len(dims) {
break Element
}
depth++
dims[depth-1] = 0
i++
case '"':
var elem = []byte{}
var escape bool
for i++; i < len(src); i++ {
if escape {
elem = append(elem, src[i])
escape = false
} else {
switch src[i] {
default:
elem = append(elem, src[i])
case '\\':
escape = true
case '"':
elems = append(elems, elem)
i++
break Element
}
}
}
default:
for start := i; i < len(src); i++ {
if bytes.HasPrefix(src[i:], del) || src[i] == '}' {
elem := src[start:i]
if len(elem) == 0 {
return nil, nil, fmt.Errorf("pq: unable to parse array; unexpected %q at offset %d", src[i], i)
}
if bytes.Equal(elem, []byte("NULL")) {
elem = nil
}
elems = append(elems, elem)
break Element
}
}
}
}
for i < len(src) {
if bytes.HasPrefix(src[i:], del) && depth > 0 {
dims[depth-1]++
i += len(del)
goto Element
} else if src[i] == '}' && depth > 0 {
dims[depth-1]++
depth--
i++
} else {
return nil, nil, fmt.Errorf("pq: unable to parse array; unexpected %q at offset %d", src[i], i)
}
}
Close:
for i < len(src) {
if src[i] == '}' && depth > 0 {
depth--
i++
} else {
return nil, nil, fmt.Errorf("pq: unable to parse array; unexpected %q at offset %d", src[i], i)
}
}
if depth > 0 {
err = fmt.Errorf("pq: unable to parse array; expected %q at offset %d", '}', i)
}
if err == nil {
for _, d := range dims {
if (len(elems) % d) != 0 {
err = fmt.Errorf("pq: multidimensional arrays must have elements with matching dimensions")
}
}
}
return
}
func scanLinearArray(src, del []byte, typ string) (elems [][]byte, err error) {
dims, elems, err := parseArray(src, del)
if err != nil {
return nil, err
}
if len(dims) > 1 {
return nil, fmt.Errorf("pq: cannot convert ARRAY%s to %s", strings.Replace(fmt.Sprint(dims), " ", "][", -1), typ)
}
return elems, err
}