tinygo/src/reflect/value.go

2022 строки
50 КиБ
Go

package reflect
import (
"math"
"unsafe"
)
type valueFlags uint8
// Flags list some useful flags that contain some extra information not
// contained in an interface{} directly, like whether this value was exported at
// all (it is possible to read unexported fields using reflection, but it is not
// possible to modify them).
const (
valueFlagIndirect valueFlags = 1 << iota
valueFlagExported
valueFlagEmbedRO
valueFlagStickyRO
valueFlagRO = valueFlagEmbedRO | valueFlagStickyRO
)
func (v valueFlags) ro() valueFlags {
if v&valueFlagRO != 0 {
return valueFlagStickyRO
}
return 0
}
type Value struct {
typecode *rawType
value unsafe.Pointer
flags valueFlags
}
// isIndirect returns whether the value pointer in this Value is always a
// pointer to the value. If it is false, it is only a pointer to the value if
// the value is bigger than a pointer.
func (v Value) isIndirect() bool {
return v.flags&valueFlagIndirect != 0
}
// isExported returns whether the value represented by this Value could be
// accessed without violating type system constraints. For example, it is not
// set for unexported struct fields.
func (v Value) isExported() bool {
return v.flags&valueFlagExported != 0
}
func (v Value) isRO() bool {
return v.flags&(valueFlagRO) != 0
}
func (v Value) checkRO() {
if v.isRO() {
panic("reflect: value is not settable")
}
}
func Indirect(v Value) Value {
if v.Kind() != Ptr {
return v
}
return v.Elem()
}
//go:linkname composeInterface runtime.composeInterface
func composeInterface(unsafe.Pointer, unsafe.Pointer) interface{}
//go:linkname decomposeInterface runtime.decomposeInterface
func decomposeInterface(i interface{}) (unsafe.Pointer, unsafe.Pointer)
func ValueOf(i interface{}) Value {
typecode, value := decomposeInterface(i)
return Value{
typecode: (*rawType)(typecode),
value: value,
flags: valueFlagExported,
}
}
func (v Value) Interface() interface{} {
if !v.isExported() {
panic("(reflect.Value).Interface: unexported")
}
return valueInterfaceUnsafe(v)
}
// valueInterfaceUnsafe is used by the runtime to hash map keys. It should not
// be subject to the isExported check.
func valueInterfaceUnsafe(v Value) interface{} {
if v.typecode.Kind() == Interface {
// The value itself is an interface. This can happen when getting the
// value of a struct field of interface type, like this:
// type T struct {
// X interface{}
// }
return *(*interface{})(v.value)
}
if v.isIndirect() && v.typecode.Size() <= unsafe.Sizeof(uintptr(0)) {
// Value was indirect but must be put back directly in the interface
// value.
var value uintptr
for j := v.typecode.Size(); j != 0; j-- {
value = (value << 8) | uintptr(*(*uint8)(unsafe.Add(v.value, j-1)))
}
v.value = unsafe.Pointer(value)
}
return composeInterface(unsafe.Pointer(v.typecode), v.value)
}
func (v Value) Type() Type {
return v.typecode
}
// IsZero reports whether v is the zero value for its type.
// It panics if the argument is invalid.
func (v Value) IsZero() bool {
switch v.Kind() {
case Bool:
return !v.Bool()
case Int, Int8, Int16, Int32, Int64:
return v.Int() == 0
case Uint, Uint8, Uint16, Uint32, Uint64, Uintptr:
return v.Uint() == 0
case Float32, Float64:
return math.Float64bits(v.Float()) == 0
case Complex64, Complex128:
c := v.Complex()
return math.Float64bits(real(c)) == 0 && math.Float64bits(imag(c)) == 0
case Array:
for i := 0; i < v.Len(); i++ {
if !v.Index(i).IsZero() {
return false
}
}
return true
case Chan, Func, Interface, Map, Pointer, Slice, UnsafePointer:
return v.IsNil()
case String:
return v.Len() == 0
case Struct:
for i := 0; i < v.NumField(); i++ {
if !v.Field(i).IsZero() {
return false
}
}
return true
default:
// This should never happens, but will act as a safeguard for
// later, as a default value doesn't makes sense here.
panic(&ValueError{Method: "reflect.Value.IsZero", Kind: v.Kind()})
}
}
// Internal function only, do not use.
//
// RawType returns the raw, underlying type code. It is used in the runtime
// package and needs to be exported for the runtime package to access it.
func (v Value) RawType() *rawType {
return v.typecode
}
func (v Value) Kind() Kind {
return v.typecode.Kind()
}
// IsNil returns whether the value is the nil value. It panics if the value Kind
// is not a channel, map, pointer, function, slice, or interface.
func (v Value) IsNil() bool {
switch v.Kind() {
case Chan, Map, Ptr, UnsafePointer:
return v.pointer() == nil
case Func:
if v.value == nil {
return true
}
fn := (*funcHeader)(v.value)
return fn.Code == nil
case Slice:
if v.value == nil {
return true
}
slice := (*sliceHeader)(v.value)
return slice.data == nil
case Interface:
val := *(*interface{})(v.value)
return val == nil
default:
panic(&ValueError{Method: "IsNil", Kind: v.Kind()})
}
}
// Pointer returns the underlying pointer of the given value for the following
// types: chan, map, pointer, unsafe.Pointer, slice, func.
func (v Value) Pointer() uintptr {
return uintptr(v.UnsafePointer())
}
// UnsafePointer returns the underlying pointer of the given value for the
// following types: chan, map, pointer, unsafe.Pointer, slice, func.
func (v Value) UnsafePointer() unsafe.Pointer {
switch v.Kind() {
case Chan, Map, Ptr, UnsafePointer:
return v.pointer()
case Slice:
slice := (*sliceHeader)(v.value)
return slice.data
case Func:
fn := (*funcHeader)(v.value)
if fn.Context != nil {
return fn.Context
}
return fn.Code
default:
panic(&ValueError{Method: "UnsafePointer", Kind: v.Kind()})
}
}
// pointer returns the underlying pointer represented by v.
// v.Kind() must be Ptr, Map, Chan, or UnsafePointer
func (v Value) pointer() unsafe.Pointer {
if v.isIndirect() {
return *(*unsafe.Pointer)(v.value)
}
return v.value
}
func (v Value) IsValid() bool {
return v.typecode != nil
}
func (v Value) CanInterface() bool {
return v.isExported() && !v.isRO()
}
func (v Value) CanAddr() bool {
return v.flags&(valueFlagIndirect) == valueFlagIndirect
}
func (v Value) Comparable() bool {
k := v.Kind()
switch k {
case Invalid:
return false
case Array:
switch v.Type().Elem().Kind() {
case Interface, Array, Struct:
for i := 0; i < v.Type().Len(); i++ {
if !v.Index(i).Comparable() {
return false
}
}
return true
}
return v.Type().Comparable()
case Interface:
return v.Elem().Comparable()
case Struct:
for i := 0; i < v.NumField(); i++ {
if !v.Field(i).Comparable() {
return false
}
}
return true
default:
return v.Type().Comparable()
}
}
func (v Value) Addr() Value {
if !v.CanAddr() {
panic("reflect.Value.Addr of unaddressable value")
}
// Preserve flagRO instead of using v.flag.ro() so that
// v.Addr().Elem() is equivalent to v (#32772)
flags := v.flags & (valueFlagExported | valueFlagRO)
return Value{
typecode: pointerTo(v.typecode),
value: v.value,
flags: flags,
}
}
func (v Value) UnsafeAddr() uintptr {
return uintptr(v.Addr().UnsafePointer())
}
func (v Value) CanSet() bool {
return v.flags&(valueFlagExported|valueFlagIndirect|valueFlagRO) == valueFlagExported|valueFlagIndirect
}
func (v Value) Bool() bool {
switch v.Kind() {
case Bool:
if v.isIndirect() {
return *((*bool)(v.value))
} else {
return uintptr(v.value) != 0
}
default:
panic(&ValueError{Method: "Bool", Kind: v.Kind()})
}
}
// CanInt reports whether Uint can be used without panicking.
func (v Value) CanInt() bool {
switch v.Kind() {
case Int, Int8, Int16, Int32, Int64:
return true
default:
return false
}
}
func (v Value) Int() int64 {
switch v.Kind() {
case Int:
if v.isIndirect() || unsafe.Sizeof(int(0)) > unsafe.Sizeof(uintptr(0)) {
return int64(*(*int)(v.value))
} else {
return int64(int(uintptr(v.value)))
}
case Int8:
if v.isIndirect() {
return int64(*(*int8)(v.value))
} else {
return int64(int8(uintptr(v.value)))
}
case Int16:
if v.isIndirect() {
return int64(*(*int16)(v.value))
} else {
return int64(int16(uintptr(v.value)))
}
case Int32:
if v.isIndirect() || unsafe.Sizeof(int32(0)) > unsafe.Sizeof(uintptr(0)) {
return int64(*(*int32)(v.value))
} else {
return int64(int32(uintptr(v.value)))
}
case Int64:
if v.isIndirect() || unsafe.Sizeof(int64(0)) > unsafe.Sizeof(uintptr(0)) {
return int64(*(*int64)(v.value))
} else {
return int64(int64(uintptr(v.value)))
}
default:
panic(&ValueError{Method: "Int", Kind: v.Kind()})
}
}
// CanUint reports whether Uint can be used without panicking.
func (v Value) CanUint() bool {
switch v.Kind() {
case Uint, Uint8, Uint16, Uint32, Uint64, Uintptr:
return true
default:
return false
}
}
func (v Value) Uint() uint64 {
switch v.Kind() {
case Uintptr:
if v.isIndirect() {
return uint64(*(*uintptr)(v.value))
} else {
return uint64(uintptr(v.value))
}
case Uint8:
if v.isIndirect() {
return uint64(*(*uint8)(v.value))
} else {
return uint64(uintptr(v.value))
}
case Uint16:
if v.isIndirect() {
return uint64(*(*uint16)(v.value))
} else {
return uint64(uintptr(v.value))
}
case Uint:
if v.isIndirect() || unsafe.Sizeof(uint(0)) > unsafe.Sizeof(uintptr(0)) {
return uint64(*(*uint)(v.value))
} else {
return uint64(uintptr(v.value))
}
case Uint32:
if v.isIndirect() || unsafe.Sizeof(uint32(0)) > unsafe.Sizeof(uintptr(0)) {
return uint64(*(*uint32)(v.value))
} else {
return uint64(uintptr(v.value))
}
case Uint64:
if v.isIndirect() || unsafe.Sizeof(uint64(0)) > unsafe.Sizeof(uintptr(0)) {
return uint64(*(*uint64)(v.value))
} else {
return uint64(uintptr(v.value))
}
default:
panic(&ValueError{Method: "Uint", Kind: v.Kind()})
}
}
// CanFloat reports whether Float can be used without panicking.
func (v Value) CanFloat() bool {
switch v.Kind() {
case Float32, Float64:
return true
default:
return false
}
}
func (v Value) Float32() float32 {
switch v.Kind() {
case Float32:
if v.isIndirect() || unsafe.Sizeof(float32(0)) > unsafe.Sizeof(uintptr(0)) {
// The float is stored as an external value on systems with 16-bit
// pointers.
return *(*float32)(v.value)
} else {
// The float is directly stored in the interface value on systems
// with 32-bit and 64-bit pointers.
return *(*float32)(unsafe.Pointer(&v.value))
}
case Float64:
return float32(v.Float())
}
panic(&ValueError{Method: "Float", Kind: v.Kind()})
}
func (v Value) Float() float64 {
switch v.Kind() {
case Float32:
if v.isIndirect() || unsafe.Sizeof(float32(0)) > unsafe.Sizeof(uintptr(0)) {
// The float is stored as an external value on systems with 16-bit
// pointers.
return float64(*(*float32)(v.value))
} else {
// The float is directly stored in the interface value on systems
// with 32-bit and 64-bit pointers.
return float64(*(*float32)(unsafe.Pointer(&v.value)))
}
case Float64:
if v.isIndirect() || unsafe.Sizeof(float64(0)) > unsafe.Sizeof(uintptr(0)) {
// For systems with 16-bit and 32-bit pointers.
return *(*float64)(v.value)
} else {
// The float is directly stored in the interface value on systems
// with 64-bit pointers.
return *(*float64)(unsafe.Pointer(&v.value))
}
default:
panic(&ValueError{Method: "Float", Kind: v.Kind()})
}
}
// CanComplex reports whether Complex can be used without panicking.
func (v Value) CanComplex() bool {
switch v.Kind() {
case Complex64, Complex128:
return true
default:
return false
}
}
func (v Value) Complex() complex128 {
switch v.Kind() {
case Complex64:
if v.isIndirect() || unsafe.Sizeof(complex64(0)) > unsafe.Sizeof(uintptr(0)) {
// The complex number is stored as an external value on systems with
// 16-bit and 32-bit pointers.
return complex128(*(*complex64)(v.value))
} else {
// The complex number is directly stored in the interface value on
// systems with 64-bit pointers.
return complex128(*(*complex64)(unsafe.Pointer(&v.value)))
}
case Complex128:
// This is a 128-bit value, which is always stored as an external value.
// It may be stored in the pointer directly on very uncommon
// architectures with 128-bit pointers, however.
return *(*complex128)(v.value)
default:
panic(&ValueError{Method: "Complex", Kind: v.Kind()})
}
}
func (v Value) String() string {
switch v.Kind() {
case String:
// A string value is always bigger than a pointer as it is made of a
// pointer and a length.
return *(*string)(v.value)
default:
// Special case because of the special treatment of .String() in Go.
return "<" + v.typecode.String() + " Value>"
}
}
func (v Value) Bytes() []byte {
switch v.Kind() {
case Slice:
if v.typecode.elem().Kind() != Uint8 {
panic(&ValueError{Method: "Bytes", Kind: v.Kind()})
}
return *(*[]byte)(v.value)
case Array:
v.checkAddressable()
if v.typecode.elem().Kind() != Uint8 {
panic(&ValueError{Method: "Bytes", Kind: v.Kind()})
}
// Small inline arrays are not addressable, so we only have to
// handle addressable arrays which will be stored as pointers
// in v.value
return unsafe.Slice((*byte)(v.value), v.Len())
}
panic(&ValueError{Method: "Bytes", Kind: v.Kind()})
}
func (v Value) Slice(i, j int) Value {
switch v.Kind() {
case Slice:
hdr := *(*sliceHeader)(v.value)
i, j := uintptr(i), uintptr(j)
if j < i || hdr.cap < j {
slicePanic()
}
elemSize := v.typecode.underlying().elem().Size()
hdr.len = j - i
hdr.cap = hdr.cap - i
hdr.data = unsafe.Add(hdr.data, i*elemSize)
return Value{
typecode: v.typecode,
value: unsafe.Pointer(&hdr),
flags: v.flags,
}
case Array:
v.checkAddressable()
buf, length := buflen(v)
i, j := uintptr(i), uintptr(j)
if j < i || length < j {
slicePanic()
}
elemSize := v.typecode.underlying().elem().Size()
var hdr sliceHeader
hdr.len = j - i
hdr.cap = length - i
hdr.data = unsafe.Add(buf, i*elemSize)
sliceType := (*arrayType)(unsafe.Pointer(v.typecode.underlying())).slicePtr
return Value{
typecode: sliceType,
value: unsafe.Pointer(&hdr),
flags: v.flags,
}
case String:
i, j := uintptr(i), uintptr(j)
str := *(*stringHeader)(v.value)
if j < i || str.len < j {
slicePanic()
}
hdr := stringHeader{
data: unsafe.Add(str.data, i),
len: j - i,
}
return Value{
typecode: v.typecode,
value: unsafe.Pointer(&hdr),
flags: v.flags,
}
}
panic(&ValueError{Method: "Slice", Kind: v.Kind()})
}
func (v Value) Slice3(i, j, k int) Value {
switch v.Kind() {
case Slice:
hdr := *(*sliceHeader)(v.value)
i, j, k := uintptr(i), uintptr(j), uintptr(k)
if j < i || k < j || hdr.len < k {
slicePanic()
}
elemSize := v.typecode.underlying().elem().Size()
hdr.len = j - i
hdr.cap = k - i
hdr.data = unsafe.Add(hdr.data, i*elemSize)
return Value{
typecode: v.typecode,
value: unsafe.Pointer(&hdr),
flags: v.flags,
}
case Array:
v.checkAddressable()
buf, length := buflen(v)
i, j, k := uintptr(i), uintptr(j), uintptr(k)
if j < i || k < j || length < k {
slicePanic()
}
elemSize := v.typecode.underlying().elem().Size()
var hdr sliceHeader
hdr.len = j - i
hdr.cap = k - i
hdr.data = unsafe.Add(buf, i*elemSize)
sliceType := (*arrayType)(unsafe.Pointer(v.typecode.underlying())).slicePtr
return Value{
typecode: sliceType,
value: unsafe.Pointer(&hdr),
flags: v.flags,
}
}
panic("unimplemented: (reflect.Value).Slice3()")
}
//go:linkname maplen runtime.hashmapLenUnsafePointer
func maplen(p unsafe.Pointer) int
//go:linkname chanlen runtime.chanLenUnsafePointer
func chanlen(p unsafe.Pointer) int
// Len returns the length of this value for slices, strings, arrays, channels,
// and maps. For other types, it panics.
func (v Value) Len() int {
switch v.typecode.Kind() {
case Array:
return v.typecode.Len()
case Chan:
return chanlen(v.pointer())
case Map:
return maplen(v.pointer())
case Slice:
return int((*sliceHeader)(v.value).len)
case String:
return int((*stringHeader)(v.value).len)
default:
panic(&ValueError{Method: "Len", Kind: v.Kind()})
}
}
//go:linkname chancap runtime.chanCapUnsafePointer
func chancap(p unsafe.Pointer) int
// Cap returns the capacity of this value for arrays, channels and slices.
// For other types, it panics.
func (v Value) Cap() int {
switch v.typecode.Kind() {
case Array:
return v.typecode.Len()
case Chan:
return chancap(v.pointer())
case Slice:
return int((*sliceHeader)(v.value).cap)
default:
panic(&ValueError{Method: "Cap", Kind: v.Kind()})
}
}
// NumField returns the number of fields of this struct. It panics for other
// value types.
func (v Value) NumField() int {
return v.typecode.NumField()
}
func (v Value) Elem() Value {
switch v.Kind() {
case Ptr:
ptr := v.pointer()
if ptr == nil {
return Value{}
}
// Don't copy RO flags
flags := (v.flags & (valueFlagIndirect | valueFlagExported)) | valueFlagIndirect
return Value{
typecode: v.typecode.elem(),
value: ptr,
flags: flags,
}
case Interface:
typecode, value := decomposeInterface(*(*interface{})(v.value))
return Value{
typecode: (*rawType)(typecode),
value: value,
flags: v.flags &^ valueFlagIndirect,
}
default:
panic(&ValueError{Method: "Elem", Kind: v.Kind()})
}
}
// Field returns the value of the i'th field of this struct.
func (v Value) Field(i int) Value {
if v.Kind() != Struct {
panic(&ValueError{Method: "Field", Kind: v.Kind()})
}
structField := v.typecode.rawField(i)
// Copy flags but clear EmbedRO; we're not an embedded field anymore
flags := v.flags & ^valueFlagEmbedRO
if structField.PkgPath != "" {
// No PkgPath => not exported.
// Clear exported flag even if the parent was exported.
flags &^= valueFlagExported
// Update the RO flag
if structField.Anonymous {
// Embedded field
flags |= valueFlagEmbedRO
} else {
flags |= valueFlagStickyRO
}
} else {
// Parent field may not have been exported but we are
flags |= valueFlagExported
}
size := v.typecode.Size()
fieldType := structField.Type
fieldSize := fieldType.Size()
if v.isIndirect() || fieldSize > unsafe.Sizeof(uintptr(0)) {
// v.value was already a pointer to the value and it should stay that
// way.
return Value{
flags: flags,
typecode: fieldType,
value: unsafe.Add(v.value, structField.Offset),
}
}
// The fieldSize is smaller than uintptr, which means that the value will
// have to be stored directly in the interface value.
if fieldSize == 0 {
// The struct field is zero sized.
// This is a rare situation, but because it's undefined behavior
// to shift the size of the value (zeroing the value), handle this
// situation explicitly.
return Value{
flags: flags,
typecode: fieldType,
value: unsafe.Pointer(nil),
}
}
if size > unsafe.Sizeof(uintptr(0)) {
// The value was not stored in the interface before but will be
// afterwards, so load the value (from the correct offset) and return
// it.
ptr := unsafe.Add(v.value, structField.Offset)
value := unsafe.Pointer(loadValue(ptr, fieldSize))
return Value{
flags: flags &^ valueFlagIndirect,
typecode: fieldType,
value: value,
}
}
// The value was already stored directly in the interface and it still
// is. Cut out the part of the value that we need.
value := maskAndShift(uintptr(v.value), structField.Offset, fieldSize)
return Value{
flags: flags,
typecode: fieldType,
value: unsafe.Pointer(value),
}
}
var uint8Type = TypeOf(uint8(0)).(*rawType)
func (v Value) Index(i int) Value {
switch v.Kind() {
case Slice:
// Extract an element from the slice.
slice := *(*sliceHeader)(v.value)
if uint(i) >= uint(slice.len) {
panic("reflect: slice index out of range")
}
flags := (v.flags & (valueFlagExported | valueFlagIndirect)) | valueFlagIndirect | v.flags.ro()
elem := Value{
typecode: v.typecode.elem(),
flags: flags,
}
elem.value = unsafe.Add(slice.data, elem.typecode.Size()*uintptr(i)) // pointer to new value
return elem
case String:
// Extract a character from a string.
// A string is never stored directly in the interface, but always as a
// pointer to the string value.
// Keeping valueFlagExported if set, but don't set valueFlagIndirect
// otherwise CanSet will return true for string elements (which is bad,
// strings are read-only).
s := *(*stringHeader)(v.value)
if uint(i) >= uint(s.len) {
panic("reflect: string index out of range")
}
return Value{
typecode: uint8Type,
value: unsafe.Pointer(uintptr(*(*uint8)(unsafe.Add(s.data, i)))),
flags: v.flags & valueFlagExported,
}
case Array:
// Extract an element from the array.
elemType := v.typecode.elem()
elemSize := elemType.Size()
size := v.typecode.Size()
if size == 0 {
// The element size is 0 and/or the length of the array is 0.
return Value{
typecode: v.typecode.elem(),
flags: v.flags,
}
}
if elemSize > unsafe.Sizeof(uintptr(0)) {
// The resulting value doesn't fit in a pointer so must be
// indirect. Also, because size != 0 this implies that the array
// length must be != 0, and thus that the total size is at least
// elemSize.
addr := unsafe.Add(v.value, elemSize*uintptr(i)) // pointer to new value
return Value{
typecode: v.typecode.elem(),
flags: v.flags,
value: addr,
}
}
if size > unsafe.Sizeof(uintptr(0)) || v.isIndirect() {
// The element fits in a pointer, but the array is not stored in the pointer directly.
// Load the value from the pointer.
addr := unsafe.Add(v.value, elemSize*uintptr(i)) // pointer to new value
value := addr
if !v.isIndirect() {
// Use a pointer to the value (don't load the value) if the
// 'indirect' flag is set.
value = unsafe.Pointer(loadValue(addr, elemSize))
}
return Value{
typecode: v.typecode.elem(),
flags: v.flags,
value: value,
}
}
// The value fits in a pointer, so extract it with some shifting and
// masking.
offset := elemSize * uintptr(i)
value := maskAndShift(uintptr(v.value), offset, elemSize)
return Value{
typecode: v.typecode.elem(),
flags: v.flags,
value: unsafe.Pointer(value),
}
default:
panic(&ValueError{Method: "Index", Kind: v.Kind()})
}
}
// loadValue loads a value that may or may not be word-aligned. The number of
// bytes given in size are loaded. The biggest possible size it can load is that
// of an uintptr.
func loadValue(ptr unsafe.Pointer, size uintptr) uintptr {
loadedValue := uintptr(0)
shift := uintptr(0)
for i := uintptr(0); i < size; i++ {
loadedValue |= uintptr(*(*byte)(ptr)) << shift
shift += 8
ptr = unsafe.Add(ptr, 1)
}
return loadedValue
}
// maskAndShift cuts out a part of a uintptr. Note that the offset may not be 0.
func maskAndShift(value, offset, size uintptr) uintptr {
mask := ^uintptr(0) >> ((unsafe.Sizeof(uintptr(0)) - size) * 8)
return (uintptr(value) >> (offset * 8)) & mask
}
func (v Value) NumMethod() int {
return v.typecode.NumMethod()
}
// OverflowFloat reports whether the float64 x cannot be represented by v's type.
// It panics if v's Kind is not Float32 or Float64.
func (v Value) OverflowFloat(x float64) bool {
k := v.Kind()
switch k {
case Float32:
return overflowFloat32(x)
case Float64:
return false
}
panic(&ValueError{Method: "reflect.Value.OverflowFloat", Kind: v.Kind()})
}
func overflowFloat32(x float64) bool {
if x < 0 {
x = -x
}
return math.MaxFloat32 < x && x <= math.MaxFloat64
}
func (v Value) MapKeys() []Value {
if v.Kind() != Map {
panic(&ValueError{Method: "MapKeys", Kind: v.Kind()})
}
// empty map
if v.Len() == 0 {
return nil
}
keys := make([]Value, 0, v.Len())
it := hashmapNewIterator()
k := New(v.typecode.Key())
e := New(v.typecode.Elem())
keyType := v.typecode.key()
keyTypeIsEmptyInterface := keyType.Kind() == Interface && keyType.NumMethod() == 0
shouldUnpackInterface := !keyTypeIsEmptyInterface && keyType.Kind() != String && !keyType.isBinary()
for hashmapNext(v.pointer(), it, k.value, e.value) {
if shouldUnpackInterface {
intf := *(*interface{})(k.value)
v := ValueOf(intf)
keys = append(keys, v)
} else {
keys = append(keys, k.Elem())
}
k = New(v.typecode.Key())
}
return keys
}
//go:linkname hashmapStringGet runtime.hashmapStringGetUnsafePointer
func hashmapStringGet(m unsafe.Pointer, key string, value unsafe.Pointer, valueSize uintptr) bool
//go:linkname hashmapBinaryGet runtime.hashmapBinaryGetUnsafePointer
func hashmapBinaryGet(m unsafe.Pointer, key, value unsafe.Pointer, valueSize uintptr) bool
//go:linkname hashmapInterfaceGet runtime.hashmapInterfaceGetUnsafePointer
func hashmapInterfaceGet(m unsafe.Pointer, key interface{}, value unsafe.Pointer, valueSize uintptr) bool
func (v Value) MapIndex(key Value) Value {
if v.Kind() != Map {
panic(&ValueError{Method: "MapIndex", Kind: v.Kind()})
}
vkey := v.typecode.key()
// compare key type with actual key type of map
if !key.typecode.AssignableTo(vkey) {
// type error?
panic("reflect.Value.MapIndex: incompatible types for key")
}
elemType := v.typecode.Elem()
elem := New(elemType)
if vkey.Kind() == String {
if ok := hashmapStringGet(v.pointer(), *(*string)(key.value), elem.value, elemType.Size()); !ok {
return Value{}
}
return elem.Elem()
} else if vkey.isBinary() {
var keyptr unsafe.Pointer
if key.isIndirect() || key.typecode.Size() > unsafe.Sizeof(uintptr(0)) {
keyptr = key.value
} else {
keyptr = unsafe.Pointer(&key.value)
}
//TODO(dgryski): zero out padding bytes in key, if any
if ok := hashmapBinaryGet(v.pointer(), keyptr, elem.value, elemType.Size()); !ok {
return Value{}
}
return elem.Elem()
} else {
if ok := hashmapInterfaceGet(v.pointer(), key.Interface(), elem.value, elemType.Size()); !ok {
return Value{}
}
return elem.Elem()
}
}
//go:linkname hashmapNewIterator runtime.hashmapNewIterator
func hashmapNewIterator() unsafe.Pointer
//go:linkname hashmapNext runtime.hashmapNextUnsafePointer
func hashmapNext(m unsafe.Pointer, it unsafe.Pointer, key, value unsafe.Pointer) bool
func (v Value) MapRange() *MapIter {
if v.Kind() != Map {
panic(&ValueError{Method: "MapRange", Kind: v.Kind()})
}
keyType := v.typecode.key()
keyTypeIsEmptyInterface := keyType.Kind() == Interface && keyType.NumMethod() == 0
shouldUnpackInterface := !keyTypeIsEmptyInterface && keyType.Kind() != String && !keyType.isBinary()
return &MapIter{
m: v,
it: hashmapNewIterator(),
unpackKeyInterface: shouldUnpackInterface,
}
}
type MapIter struct {
m Value
it unsafe.Pointer
key Value
val Value
valid bool
unpackKeyInterface bool
}
func (it *MapIter) Key() Value {
if !it.valid {
panic("reflect.MapIter.Key called on invalid iterator")
}
if it.unpackKeyInterface {
intf := *(*interface{})(it.key.value)
v := ValueOf(intf)
return v
}
return it.key.Elem()
}
func (it *MapIter) Value() Value {
if !it.valid {
panic("reflect.MapIter.Value called on invalid iterator")
}
return it.val.Elem()
}
func (it *MapIter) Next() bool {
it.key = New(it.m.typecode.Key())
it.val = New(it.m.typecode.Elem())
it.valid = hashmapNext(it.m.pointer(), it.it, it.key.value, it.val.value)
return it.valid
}
func (v Value) Set(x Value) {
v.checkAddressable()
v.checkRO()
if !x.typecode.AssignableTo(v.typecode) {
panic("reflect: cannot set")
}
if v.typecode.Kind() == Interface && x.typecode.Kind() != Interface {
intf := composeInterface(unsafe.Pointer(x.typecode), x.value)
x = Value{
typecode: v.typecode,
value: unsafe.Pointer(&intf),
}
}
size := v.typecode.Size()
xptr := x.value
if size <= unsafe.Sizeof(uintptr(0)) && !x.isIndirect() {
value := x.value
xptr = unsafe.Pointer(&value)
}
memcpy(v.value, xptr, size)
}
func (v Value) SetZero() {
v.checkAddressable()
v.checkRO()
size := v.typecode.Size()
memzero(v.value, size)
}
func (v Value) SetBool(x bool) {
v.checkAddressable()
v.checkRO()
switch v.Kind() {
case Bool:
*(*bool)(v.value) = x
default:
panic(&ValueError{Method: "SetBool", Kind: v.Kind()})
}
}
func (v Value) SetInt(x int64) {
v.checkAddressable()
v.checkRO()
switch v.Kind() {
case Int:
*(*int)(v.value) = int(x)
case Int8:
*(*int8)(v.value) = int8(x)
case Int16:
*(*int16)(v.value) = int16(x)
case Int32:
*(*int32)(v.value) = int32(x)
case Int64:
*(*int64)(v.value) = x
default:
panic(&ValueError{Method: "SetInt", Kind: v.Kind()})
}
}
func (v Value) SetUint(x uint64) {
v.checkAddressable()
v.checkRO()
switch v.Kind() {
case Uint:
*(*uint)(v.value) = uint(x)
case Uint8:
*(*uint8)(v.value) = uint8(x)
case Uint16:
*(*uint16)(v.value) = uint16(x)
case Uint32:
*(*uint32)(v.value) = uint32(x)
case Uint64:
*(*uint64)(v.value) = x
case Uintptr:
*(*uintptr)(v.value) = uintptr(x)
default:
panic(&ValueError{Method: "SetUint", Kind: v.Kind()})
}
}
func (v Value) SetFloat(x float64) {
v.checkAddressable()
v.checkRO()
switch v.Kind() {
case Float32:
*(*float32)(v.value) = float32(x)
case Float64:
*(*float64)(v.value) = x
default:
panic(&ValueError{Method: "SetFloat", Kind: v.Kind()})
}
}
func (v Value) SetComplex(x complex128) {
v.checkAddressable()
v.checkRO()
switch v.Kind() {
case Complex64:
*(*complex64)(v.value) = complex64(x)
case Complex128:
*(*complex128)(v.value) = x
default:
panic(&ValueError{Method: "SetComplex", Kind: v.Kind()})
}
}
func (v Value) SetString(x string) {
v.checkAddressable()
v.checkRO()
switch v.Kind() {
case String:
*(*string)(v.value) = x
default:
panic(&ValueError{Method: "SetString", Kind: v.Kind()})
}
}
func (v Value) SetBytes(x []byte) {
v.checkAddressable()
v.checkRO()
if v.typecode.Kind() != Slice || v.typecode.elem().Kind() != Uint8 {
panic("reflect.Value.SetBytes called on not []byte")
}
// copy the header contents over
*(*[]byte)(v.value) = x
}
func (v Value) SetCap(n int) {
panic("unimplemented: (reflect.Value).SetCap()")
}
func (v Value) SetLen(n int) {
if v.typecode.Kind() != Slice {
panic(&ValueError{Method: "reflect.Value.SetLen", Kind: v.Kind()})
}
v.checkAddressable()
hdr := (*sliceHeader)(v.value)
if int(uintptr(n)) != n || uintptr(n) > hdr.cap {
panic("reflect.Value.SetLen: slice length out of range")
}
hdr.len = uintptr(n)
}
func (v Value) checkAddressable() {
if !v.isIndirect() {
panic("reflect: value is not addressable")
}
}
// OverflowInt reports whether the int64 x cannot be represented by v's type.
// It panics if v's Kind is not Int, Int8, Int16, Int32, or Int64.
func (v Value) OverflowInt(x int64) bool {
switch v.Kind() {
case Int, Int8, Int16, Int32, Int64:
bitSize := v.typecode.Size() * 8
trunc := (x << (64 - bitSize)) >> (64 - bitSize)
return x != trunc
}
panic(&ValueError{Method: "reflect.Value.OverflowInt", Kind: v.Kind()})
}
// OverflowUint reports whether the uint64 x cannot be represented by v's type.
// It panics if v's Kind is not Uint, Uintptr, Uint8, Uint16, Uint32, or Uint64.
func (v Value) OverflowUint(x uint64) bool {
k := v.Kind()
switch k {
case Uint, Uintptr, Uint8, Uint16, Uint32, Uint64:
bitSize := v.typecode.Size() * 8
trunc := (x << (64 - bitSize)) >> (64 - bitSize)
return x != trunc
}
panic(&ValueError{Method: "reflect.Value.OverflowUint", Kind: v.Kind()})
}
func (v Value) CanConvert(t Type) bool {
panic("unimplemented: (reflect.Value).CanConvert()")
}
func (v Value) Convert(t Type) Value {
if v, ok := convertOp(v, t); ok {
return v
}
panic("reflect.Value.Convert: value of type " + v.typecode.String() + " cannot be converted to type " + t.String())
}
func convertOp(src Value, typ Type) (Value, bool) {
// Easy check first. Do we even need to do anything?
if src.typecode.underlying() == typ.(*rawType).underlying() {
return Value{
typecode: typ.(*rawType),
value: src.value,
flags: src.flags,
}, true
}
switch src.Kind() {
case Int, Int8, Int16, Int32, Int64:
switch rtype := typ.(*rawType); rtype.Kind() {
case Int, Int8, Int16, Int32, Int64, Uint, Uint8, Uint16, Uint32, Uint64, Uintptr:
return cvtInt(src, rtype), true
case Float32, Float64:
return cvtIntFloat(src, rtype), true
case String:
return cvtIntString(src, rtype), true
}
case Uint, Uint8, Uint16, Uint32, Uint64, Uintptr:
switch rtype := typ.(*rawType); rtype.Kind() {
case Int, Int8, Int16, Int32, Int64, Uint, Uint8, Uint16, Uint32, Uint64, Uintptr:
return cvtUint(src, rtype), true
case Float32, Float64:
return cvtUintFloat(src, rtype), true
case String:
return cvtUintString(src, rtype), true
}
case Float32, Float64:
switch rtype := typ.(*rawType); rtype.Kind() {
case Int, Int8, Int16, Int32, Int64:
return cvtFloatInt(src, rtype), true
case Uint, Uint8, Uint16, Uint32, Uint64, Uintptr:
return cvtFloatUint(src, rtype), true
case Float32, Float64:
return cvtFloat(src, rtype), true
}
/*
case Complex64, Complex128:
switch src.Kind() {
case Complex64, Complex128:
return cvtComplex
}
*/
case Slice:
if typ.Kind() == String && !src.typecode.elem().isNamed() {
rtype := typ.(*rawType)
switch src.Type().Elem().Kind() {
case Uint8:
return cvtBytesString(src, rtype), true
case Int32:
return cvtRunesString(src, rtype), true
}
}
case String:
rtype := typ.(*rawType)
if typ.Kind() == Slice && !rtype.elem().isNamed() {
switch typ.Elem().Kind() {
case Uint8:
return cvtStringBytes(src, rtype), true
case Int32:
return cvtStringRunes(src, rtype), true
}
}
}
// TODO(dgryski): Unimplemented:
// Chan
// Non-defined pointers types with same underlying base type
// Interface <-> Type conversions
return Value{}, false
}
func cvtInt(v Value, t *rawType) Value {
return makeInt(v.flags, uint64(v.Int()), t)
}
func cvtUint(v Value, t *rawType) Value {
return makeInt(v.flags, v.Uint(), t)
}
func cvtIntFloat(v Value, t *rawType) Value {
return makeFloat(v.flags, float64(v.Int()), t)
}
func cvtUintFloat(v Value, t *rawType) Value {
return makeFloat(v.flags, float64(v.Uint()), t)
}
func cvtFloatInt(v Value, t *rawType) Value {
return makeInt(v.flags, uint64(int64(v.Float())), t)
}
func cvtFloatUint(v Value, t *rawType) Value {
return makeInt(v.flags, uint64(v.Float()), t)
}
func cvtFloat(v Value, t *rawType) Value {
if v.Type().Kind() == Float32 && t.Kind() == Float32 {
// Don't do any conversion if both types have underlying type float32.
// This avoids converting to float64 and back, which will
// convert a signaling NaN to a quiet NaN. See issue 36400.
return makeFloat32(v.flags, v.Float32(), t)
}
return makeFloat(v.flags, v.Float(), t)
}
//go:linkname stringToBytes runtime.stringToBytes
func stringToBytes(x string) []byte
func cvtStringBytes(v Value, t *rawType) Value {
b := stringToBytes(*(*string)(v.value))
return Value{
typecode: t,
value: unsafe.Pointer(&b),
flags: v.flags,
}
}
//go:linkname stringFromBytes runtime.stringFromBytes
func stringFromBytes(x []byte) string
func cvtBytesString(v Value, t *rawType) Value {
s := stringFromBytes(*(*[]byte)(v.value))
return Value{
typecode: t,
value: unsafe.Pointer(&s),
flags: v.flags,
}
}
func makeInt(flags valueFlags, bits uint64, t *rawType) Value {
size := t.Size()
v := Value{
typecode: t,
flags: flags,
}
ptr := unsafe.Pointer(&v.value)
if size > unsafe.Sizeof(uintptr(0)) {
ptr = alloc(size, nil)
v.value = ptr
}
switch size {
case 1:
*(*uint8)(ptr) = uint8(bits)
case 2:
*(*uint16)(ptr) = uint16(bits)
case 4:
*(*uint32)(ptr) = uint32(bits)
case 8:
*(*uint64)(ptr) = bits
}
return v
}
func makeFloat(flags valueFlags, f float64, t *rawType) Value {
size := t.Size()
v := Value{
typecode: t,
flags: flags,
}
ptr := unsafe.Pointer(&v.value)
if size > unsafe.Sizeof(uintptr(0)) {
ptr = alloc(size, nil)
v.value = ptr
}
switch size {
case 4:
*(*float32)(ptr) = float32(f)
case 8:
*(*float64)(ptr) = f
}
return v
}
func makeFloat32(flags valueFlags, f float32, t *rawType) Value {
v := Value{
typecode: t,
flags: flags,
}
*(*float32)(unsafe.Pointer(&v.value)) = float32(f)
return v
}
func cvtIntString(src Value, t *rawType) Value {
panic("cvtUintString: unimplemented")
}
func cvtUintString(src Value, t *rawType) Value {
panic("cvtUintString: unimplemented")
}
func cvtStringRunes(src Value, t *rawType) Value {
panic("cvsStringRunes: unimplemented")
}
func cvtRunesString(src Value, t *rawType) Value {
panic("cvsRunesString: unimplemented")
}
//go:linkname slicePanic runtime.slicePanic
func slicePanic()
func MakeSlice(typ Type, len, cap int) Value {
if typ.Kind() != Slice {
panic("reflect.MakeSlice of non-slice type")
}
rtype := typ.(*rawType)
ulen := uint(len)
ucap := uint(cap)
maxSize := (^uintptr(0)) / 2
elementSize := rtype.elem().Size()
if elementSize > 1 {
maxSize /= uintptr(elementSize)
}
if ulen > ucap || ucap > uint(maxSize) {
slicePanic()
}
// This can't overflow because of the above checks.
size := uintptr(ucap) * elementSize
var slice sliceHeader
slice.cap = uintptr(ucap)
slice.len = uintptr(ulen)
slice.data = alloc(size, nil)
return Value{
typecode: rtype,
value: unsafe.Pointer(&slice),
flags: valueFlagExported,
}
}
var zerobuffer unsafe.Pointer
const zerobufferLen = 32
func init() {
// 32 characters of zero bytes
zerobufferStr := "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
s := (*stringHeader)(unsafe.Pointer(&zerobufferStr))
zerobuffer = s.data
}
func Zero(typ Type) Value {
size := typ.Size()
if size <= unsafe.Sizeof(uintptr(0)) {
return Value{
typecode: typ.(*rawType),
value: nil,
flags: valueFlagExported | valueFlagRO,
}
}
if size <= zerobufferLen {
return Value{
typecode: typ.(*rawType),
value: unsafe.Pointer(zerobuffer),
flags: valueFlagExported | valueFlagRO,
}
}
return Value{
typecode: typ.(*rawType),
value: alloc(size, nil),
flags: valueFlagExported | valueFlagRO,
}
}
// New is the reflect equivalent of the new(T) keyword, returning a pointer to a
// new value of the given type.
func New(typ Type) Value {
return Value{
typecode: pointerTo(typ.(*rawType)),
value: alloc(typ.Size(), nil),
flags: valueFlagExported,
}
}
type funcHeader struct {
Context unsafe.Pointer
Code unsafe.Pointer
}
type SliceHeader struct {
Data uintptr
Len uintptr
Cap uintptr
}
// Slice header that matches the underlying structure. Used for when we switch
// to a precise GC, which needs to know exactly where pointers live.
type sliceHeader struct {
data unsafe.Pointer
len uintptr
cap uintptr
}
type StringHeader struct {
Data uintptr
Len uintptr
}
// Like sliceHeader, this type is used internally to make sure pointer and
// non-pointer fields match those of actual strings.
type stringHeader struct {
data unsafe.Pointer
len uintptr
}
type ValueError struct {
Method string
Kind Kind
}
func (e *ValueError) Error() string {
if e.Kind == 0 {
return "reflect: call of " + e.Method + " on zero Value"
}
return "reflect: call of " + e.Method + " on " + e.Kind.String() + " Value"
}
//go:linkname memcpy runtime.memcpy
func memcpy(dst, src unsafe.Pointer, size uintptr)
//go:linkname memzero runtime.memzero
func memzero(ptr unsafe.Pointer, size uintptr)
//go:linkname alloc runtime.alloc
func alloc(size uintptr, layout unsafe.Pointer) unsafe.Pointer
//go:linkname sliceAppend runtime.sliceAppend
func sliceAppend(srcBuf, elemsBuf unsafe.Pointer, srcLen, srcCap, elemsLen uintptr, elemSize uintptr) (unsafe.Pointer, uintptr, uintptr)
//go:linkname sliceCopy runtime.sliceCopy
func sliceCopy(dst, src unsafe.Pointer, dstLen, srcLen uintptr, elemSize uintptr) int
// Copy copies the contents of src into dst until either
// dst has been filled or src has been exhausted.
func Copy(dst, src Value) int {
compatibleTypes := false ||
// dst and src are both slices or arrays with equal types
((dst.typecode.Kind() == Slice || dst.typecode.Kind() == Array) &&
(src.typecode.Kind() == Slice || src.typecode.Kind() == Array) &&
(dst.typecode.elem() == src.typecode.elem())) ||
// dst is array or slice of uint8 and src is string
((dst.typecode.Kind() == Slice || dst.typecode.Kind() == Array) &&
dst.typecode.elem().Kind() == Uint8 &&
src.typecode.Kind() == String)
if !compatibleTypes {
panic("Copy: type mismatch: " + dst.typecode.String() + "/" + src.typecode.String())
}
// Can read from an unaddressable array but not write to one.
if dst.typecode.Kind() == Array && !dst.isIndirect() {
panic("reflect.Copy: unaddressable array value")
}
dstbuf, dstlen := buflen(dst)
srcbuf, srclen := buflen(src)
if srclen > 0 {
dst.checkRO()
}
return sliceCopy(dstbuf, srcbuf, dstlen, srclen, dst.typecode.elem().Size())
}
func buflen(v Value) (unsafe.Pointer, uintptr) {
var buf unsafe.Pointer
var len uintptr
switch v.typecode.Kind() {
case Slice:
hdr := (*sliceHeader)(v.value)
buf = hdr.data
len = hdr.len
case Array:
if v.isIndirect() {
buf = v.value
} else {
buf = unsafe.Pointer(&v.value)
}
len = uintptr(v.Len())
case String:
hdr := (*stringHeader)(v.value)
buf = hdr.data
len = hdr.len
default:
// This shouldn't happen
panic("reflect.Copy: not slice or array or string")
}
return buf, len
}
//go:linkname sliceGrow runtime.sliceGrow
func sliceGrow(buf unsafe.Pointer, oldLen, oldCap, newCap, elemSize uintptr) (unsafe.Pointer, uintptr, uintptr)
// extend slice to hold n new elements
func extendSlice(v Value, n int) sliceHeader {
if v.Kind() != Slice {
panic(&ValueError{Method: "extendSlice", Kind: v.Kind()})
}
var old sliceHeader
if v.value != nil {
old = *(*sliceHeader)(v.value)
}
var nbuf unsafe.Pointer
var nlen, ncap uintptr
if old.len+uintptr(n) > old.cap {
// we need to grow the slice
nbuf, nlen, ncap = sliceGrow(old.data, old.len, old.cap, old.cap+uintptr(n), v.typecode.elem().Size())
} else {
// we can reuse the slice we have
nbuf = old.data
nlen = old.len
ncap = old.cap
}
return sliceHeader{
data: nbuf,
len: nlen + uintptr(n),
cap: ncap,
}
}
// Append appends the values x to a slice s and returns the resulting slice.
// As in Go, each x's value must be assignable to the slice's element type.
func Append(v Value, x ...Value) Value {
if v.Kind() != Slice {
panic(&ValueError{Method: "Append", Kind: v.Kind()})
}
oldLen := v.Len()
newslice := extendSlice(v, len(x))
v.flags = valueFlagExported
v.value = (unsafe.Pointer)(&newslice)
for i, xx := range x {
v.Index(oldLen + i).Set(xx)
}
return v
}
// AppendSlice appends a slice t to a slice s and returns the resulting slice.
// The slices s and t must have the same element type.
func AppendSlice(s, t Value) Value {
if s.typecode.Kind() != Slice || t.typecode.Kind() != Slice || s.typecode != t.typecode {
// Not a very helpful error message, but shortened to just one error to
// keep code size down.
panic("reflect.AppendSlice: invalid types")
}
if !s.isExported() || !t.isExported() {
// One of the sides was not exported, so can't access the data.
panic("reflect.AppendSlice: unexported")
}
sSlice := (*sliceHeader)(s.value)
tSlice := (*sliceHeader)(t.value)
elemSize := s.typecode.elem().Size()
ptr, len, cap := sliceAppend(sSlice.data, tSlice.data, sSlice.len, sSlice.cap, tSlice.len, elemSize)
result := &sliceHeader{
data: ptr,
len: len,
cap: cap,
}
return Value{
typecode: s.typecode,
value: unsafe.Pointer(result),
flags: valueFlagExported,
}
}
// Grow increases the slice's capacity, if necessary, to guarantee space for
// another n elements. After Grow(n), at least n elements can be appended
// to the slice without another allocation.
//
// It panics if v's Kind is not a Slice or if n is negative or too large to
// allocate the memory.
func (v Value) Grow(n int) {
v.checkAddressable()
if n < 0 {
panic("reflect.Grow: negative length")
}
if v.Kind() != Slice {
panic(&ValueError{Method: "Grow", Kind: v.Kind()})
}
slice := (*sliceHeader)(v.value)
newslice := extendSlice(v, n)
// Only copy the new data and cap: the len remains unchanged.
slice.data = newslice.data
slice.cap = newslice.cap
}
//go:linkname hashmapStringSet runtime.hashmapStringSetUnsafePointer
func hashmapStringSet(m unsafe.Pointer, key string, value unsafe.Pointer)
//go:linkname hashmapBinarySet runtime.hashmapBinarySetUnsafePointer
func hashmapBinarySet(m unsafe.Pointer, key, value unsafe.Pointer)
//go:linkname hashmapInterfaceSet runtime.hashmapInterfaceSetUnsafePointer
func hashmapInterfaceSet(m unsafe.Pointer, key interface{}, value unsafe.Pointer)
//go:linkname hashmapStringDelete runtime.hashmapStringDeleteUnsafePointer
func hashmapStringDelete(m unsafe.Pointer, key string)
//go:linkname hashmapBinaryDelete runtime.hashmapBinaryDeleteUnsafePointer
func hashmapBinaryDelete(m unsafe.Pointer, key unsafe.Pointer)
//go:linkname hashmapInterfaceDelete runtime.hashmapInterfaceDeleteUnsafePointer
func hashmapInterfaceDelete(m unsafe.Pointer, key interface{})
func (v Value) SetMapIndex(key, elem Value) {
v.checkRO()
if v.Kind() != Map {
panic(&ValueError{Method: "SetMapIndex", Kind: v.Kind()})
}
vkey := v.typecode.key()
// compare key type with actual key type of map
if !key.typecode.AssignableTo(vkey) {
panic("reflect.Value.SetMapIndex: incompatible types for key")
}
// if elem is the zero Value, it means delete
del := elem == Value{}
if !del && !elem.typecode.AssignableTo(v.typecode.elem()) {
panic("reflect.Value.SetMapIndex: incompatible types for value")
}
// make elem an interface if it needs to be converted
if v.typecode.elem().Kind() == Interface && elem.typecode.Kind() != Interface {
intf := composeInterface(unsafe.Pointer(elem.typecode), elem.value)
elem = Value{
typecode: v.typecode.elem(),
value: unsafe.Pointer(&intf),
}
}
if key.Kind() == String {
if del {
hashmapStringDelete(v.pointer(), *(*string)(key.value))
} else {
var elemptr unsafe.Pointer
if elem.isIndirect() || elem.typecode.Size() > unsafe.Sizeof(uintptr(0)) {
elemptr = elem.value
} else {
elemptr = unsafe.Pointer(&elem.value)
}
hashmapStringSet(v.pointer(), *(*string)(key.value), elemptr)
}
} else if key.typecode.isBinary() {
var keyptr unsafe.Pointer
if key.isIndirect() || key.typecode.Size() > unsafe.Sizeof(uintptr(0)) {
keyptr = key.value
} else {
keyptr = unsafe.Pointer(&key.value)
}
if del {
hashmapBinaryDelete(v.pointer(), keyptr)
} else {
var elemptr unsafe.Pointer
if elem.isIndirect() || elem.typecode.Size() > unsafe.Sizeof(uintptr(0)) {
elemptr = elem.value
} else {
elemptr = unsafe.Pointer(&elem.value)
}
hashmapBinarySet(v.pointer(), keyptr, elemptr)
}
} else {
if del {
hashmapInterfaceDelete(v.pointer(), key.Interface())
} else {
var elemptr unsafe.Pointer
if elem.isIndirect() || elem.typecode.Size() > unsafe.Sizeof(uintptr(0)) {
elemptr = elem.value
} else {
elemptr = unsafe.Pointer(&elem.value)
}
hashmapInterfaceSet(v.pointer(), key.Interface(), elemptr)
}
}
}
// FieldByIndex returns the nested field corresponding to index.
func (v Value) FieldByIndex(index []int) Value {
if len(index) == 1 {
return v.Field(index[0])
}
if v.Kind() != Struct {
panic(&ValueError{"FieldByIndex", v.Kind()})
}
for i, x := range index {
if i > 0 {
if v.Kind() == Pointer && v.typecode.elem().Kind() == Struct {
if v.IsNil() {
panic("reflect: indirection through nil pointer to embedded struct")
}
v = v.Elem()
}
}
v = v.Field(x)
}
return v
}
// FieldByIndexErr returns the nested field corresponding to index.
func (v Value) FieldByIndexErr(index []int) (Value, error) {
return Value{}, &ValueError{Method: "FieldByIndexErr"}
}
func (v Value) FieldByName(name string) Value {
if v.Kind() != Struct {
panic(&ValueError{"FieldByName", v.Kind()})
}
if field, ok := v.typecode.FieldByName(name); ok {
return v.FieldByIndex(field.Index)
}
return Value{}
}
func (v Value) FieldByNameFunc(match func(string) bool) Value {
if v.Kind() != Struct {
panic(&ValueError{"FieldByName", v.Kind()})
}
if field, ok := v.typecode.FieldByNameFunc(match); ok {
return v.FieldByIndex(field.Index)
}
return Value{}
}
//go:linkname hashmapMake runtime.hashmapMakeUnsafePointer
func hashmapMake(keySize, valueSize uintptr, sizeHint uintptr, alg uint8) unsafe.Pointer
// MakeMapWithSize creates a new map with the specified type and initial space
// for approximately n elements.
func MakeMapWithSize(typ Type, n int) Value {
// TODO(dgryski): deduplicate these? runtime and reflect both need them.
const (
hashmapAlgorithmBinary uint8 = iota
hashmapAlgorithmString
hashmapAlgorithmInterface
)
if typ.Kind() != Map {
panic(&ValueError{Method: "MakeMap", Kind: typ.Kind()})
}
if n < 0 {
panic("reflect.MakeMapWithSize: negative size hint")
}
key := typ.Key().(*rawType)
val := typ.Elem().(*rawType)
var alg uint8
if key.Kind() == String {
alg = hashmapAlgorithmString
} else if key.isBinary() {
alg = hashmapAlgorithmBinary
} else {
alg = hashmapAlgorithmInterface
}
m := hashmapMake(key.Size(), val.Size(), uintptr(n), alg)
return Value{
typecode: typ.(*rawType),
value: m,
flags: valueFlagExported,
}
}
type SelectDir int
const (
_ SelectDir = iota
SelectSend // case Chan <- Send
SelectRecv // case <-Chan:
SelectDefault // default
)
type SelectCase struct {
Dir SelectDir // direction of case
Chan Value // channel to use (for send or receive)
Send Value // value to send (for send)
}
func Select(cases []SelectCase) (chosen int, recv Value, recvOK bool) {
panic("unimplemented: reflect.Select")
}
func (v Value) Send(x Value) {
panic("unimplemented: reflect.Value.Send()")
}
func (v Value) Close() {
panic("unimplemented: reflect.Value.Close()")
}
// MakeMap creates a new map with the specified type.
func MakeMap(typ Type) Value {
return MakeMapWithSize(typ, 8)
}
func (v Value) Call(in []Value) []Value {
panic("unimplemented: (reflect.Value).Call()")
}
func (v Value) Method(i int) Value {
panic("unimplemented: (reflect.Value).Method()")
}
func (v Value) MethodByName(name string) Value {
panic("unimplemented: (reflect.Value).MethodByName()")
}
func (v Value) Recv() (x Value, ok bool) {
panic("unimplemented: (reflect.Value).Recv()")
}
func NewAt(typ Type, p unsafe.Pointer) Value {
panic("unimplemented: reflect.New()")
}