1317 lines
32 KiB
Go
1317 lines
32 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package reflect
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import (
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"math"
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"runtime"
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"unsafe"
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)
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const ptrSize = uintptr(unsafe.Sizeof((*byte)(nil)))
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const cannotSet = "cannot set value obtained from unexported struct field"
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type addr unsafe.Pointer
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// TODO: This will have to go away when
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// the new gc goes in.
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func memmove(adst, asrc addr, n uintptr) {
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dst := uintptr(adst)
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src := uintptr(asrc)
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switch {
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case src < dst && src+n > dst:
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// byte copy backward
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// careful: i is unsigned
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for i := n; i > 0; {
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i--
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*(*byte)(addr(dst + i)) = *(*byte)(addr(src + i))
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}
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case (n|src|dst)&(ptrSize-1) != 0:
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// byte copy forward
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for i := uintptr(0); i < n; i++ {
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*(*byte)(addr(dst + i)) = *(*byte)(addr(src + i))
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}
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default:
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// word copy forward
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for i := uintptr(0); i < n; i += ptrSize {
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*(*uintptr)(addr(dst + i)) = *(*uintptr)(addr(src + i))
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}
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}
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}
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// Value is the common interface to reflection values.
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// The implementations of Value (e.g., ArrayValue, StructValue)
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// have additional type-specific methods.
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type Value interface {
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// Type returns the value's type.
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Type() Type
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// Interface returns the value as an interface{}.
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Interface() interface{}
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// CanSet returns true if the value can be changed.
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// Values obtained by the use of non-exported struct fields
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// can be used in Get but not Set.
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// If CanSet returns false, calling the type-specific Set will panic.
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CanSet() bool
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// SetValue assigns v to the value; v must have the same type as the value.
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SetValue(v Value)
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// CanAddr returns true if the value's address can be obtained with Addr.
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// Such values are called addressable. A value is addressable if it is
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// an element of a slice, an element of an addressable array,
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// a field of an addressable struct, the result of dereferencing a pointer,
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// or the result of a call to NewValue, MakeChan, MakeMap, or MakeZero.
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// If CanAddr returns false, calling Addr will panic.
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CanAddr() bool
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// Addr returns the address of the value.
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// If the value is not addressable, Addr panics.
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// Addr is typically used to obtain a pointer to a struct field or slice element
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// in order to call a method that requires a pointer receiver.
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Addr() *PtrValue
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// UnsafeAddr returns a pointer to the underlying data.
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// It is for advanced clients that also import the "unsafe" package.
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UnsafeAddr() uintptr
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// Method returns a FuncValue corresponding to the value's i'th method.
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// The arguments to a Call on the returned FuncValue
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// should not include a receiver; the FuncValue will use
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// the value as the receiver.
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Method(i int) *FuncValue
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getAddr() addr
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}
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// flags for value
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const (
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canSet uint32 = 1 << iota // can set value (write to *v.addr)
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canAddr // can take address of value
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canStore // can store through value (write to **v.addr)
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)
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// value is the common implementation of most values.
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// It is embedded in other, public struct types, but always
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// with a unique tag like "uint" or "float" so that the client cannot
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// convert from, say, *UintValue to *FloatValue.
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type value struct {
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typ Type
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addr addr
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flag uint32
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}
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func (v *value) Type() Type { return v.typ }
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func (v *value) Addr() *PtrValue {
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if !v.CanAddr() {
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panic("reflect: cannot take address of value")
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}
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a := v.addr
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flag := canSet
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if v.CanSet() {
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flag |= canStore
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}
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// We could safely set canAddr here too -
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// the caller would get the address of a -
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// but it doesn't match the Go model.
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// The language doesn't let you say &&v.
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return newValue(PtrTo(v.typ), addr(&a), flag).(*PtrValue)
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}
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func (v *value) UnsafeAddr() uintptr { return uintptr(v.addr) }
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func (v *value) getAddr() addr { return v.addr }
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func (v *value) Interface() interface{} {
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if typ, ok := v.typ.(*InterfaceType); ok {
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// There are two different representations of interface values,
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// one if the interface type has methods and one if it doesn't.
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// These two representations require different expressions
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// to extract correctly.
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if typ.NumMethod() == 0 {
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// Extract as interface value without methods.
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return *(*interface{})(v.addr)
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}
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// Extract from v.addr as interface value with methods.
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return *(*interface {
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m()
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})(v.addr)
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}
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return unsafe.Unreflect(v.typ, unsafe.Pointer(v.addr))
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}
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func (v *value) CanSet() bool { return v.flag&canSet != 0 }
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func (v *value) CanAddr() bool { return v.flag&canAddr != 0 }
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/*
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* basic types
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*/
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// BoolValue represents a bool value.
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type BoolValue struct {
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value "bool"
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}
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// Get returns the underlying bool value.
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func (v *BoolValue) Get() bool { return *(*bool)(v.addr) }
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// Set sets v to the value x.
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func (v *BoolValue) Set(x bool) {
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if !v.CanSet() {
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panic(cannotSet)
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}
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*(*bool)(v.addr) = x
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}
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// Set sets v to the value x.
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func (v *BoolValue) SetValue(x Value) { v.Set(x.(*BoolValue).Get()) }
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// FloatValue represents a float value.
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type FloatValue struct {
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value "float"
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}
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// Get returns the underlying int value.
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func (v *FloatValue) Get() float64 {
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switch v.typ.Kind() {
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case Float32:
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return float64(*(*float32)(v.addr))
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case Float64:
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return *(*float64)(v.addr)
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}
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panic("reflect: invalid float kind")
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}
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// Set sets v to the value x.
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func (v *FloatValue) Set(x float64) {
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if !v.CanSet() {
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panic(cannotSet)
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}
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switch v.typ.Kind() {
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default:
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panic("reflect: invalid float kind")
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case Float32:
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*(*float32)(v.addr) = float32(x)
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case Float64:
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*(*float64)(v.addr) = x
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}
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}
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// Overflow returns true if x cannot be represented by the type of v.
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func (v *FloatValue) Overflow(x float64) bool {
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if v.typ.Size() == 8 {
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return false
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}
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if x < 0 {
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x = -x
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}
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return math.MaxFloat32 < x && x <= math.MaxFloat64
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}
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// Set sets v to the value x.
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func (v *FloatValue) SetValue(x Value) { v.Set(x.(*FloatValue).Get()) }
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// ComplexValue represents a complex value.
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type ComplexValue struct {
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value "complex"
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}
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// Get returns the underlying complex value.
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func (v *ComplexValue) Get() complex128 {
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switch v.typ.Kind() {
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case Complex64:
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return complex128(*(*complex64)(v.addr))
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case Complex128:
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return *(*complex128)(v.addr)
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}
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panic("reflect: invalid complex kind")
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}
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// Set sets v to the value x.
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func (v *ComplexValue) Set(x complex128) {
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if !v.CanSet() {
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panic(cannotSet)
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}
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switch v.typ.Kind() {
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default:
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panic("reflect: invalid complex kind")
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case Complex64:
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*(*complex64)(v.addr) = complex64(x)
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case Complex128:
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*(*complex128)(v.addr) = x
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}
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}
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// Set sets v to the value x.
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func (v *ComplexValue) SetValue(x Value) { v.Set(x.(*ComplexValue).Get()) }
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// IntValue represents an int value.
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type IntValue struct {
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value "int"
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}
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// Get returns the underlying int value.
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func (v *IntValue) Get() int64 {
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switch v.typ.Kind() {
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case Int:
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return int64(*(*int)(v.addr))
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case Int8:
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return int64(*(*int8)(v.addr))
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case Int16:
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return int64(*(*int16)(v.addr))
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case Int32:
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return int64(*(*int32)(v.addr))
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case Int64:
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return *(*int64)(v.addr)
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}
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panic("reflect: invalid int kind")
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}
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// Set sets v to the value x.
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func (v *IntValue) Set(x int64) {
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if !v.CanSet() {
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panic(cannotSet)
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}
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switch v.typ.Kind() {
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default:
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panic("reflect: invalid int kind")
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case Int:
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*(*int)(v.addr) = int(x)
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case Int8:
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*(*int8)(v.addr) = int8(x)
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case Int16:
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*(*int16)(v.addr) = int16(x)
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case Int32:
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*(*int32)(v.addr) = int32(x)
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case Int64:
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*(*int64)(v.addr) = x
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}
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}
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// Set sets v to the value x.
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func (v *IntValue) SetValue(x Value) { v.Set(x.(*IntValue).Get()) }
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// Overflow returns true if x cannot be represented by the type of v.
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func (v *IntValue) Overflow(x int64) bool {
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bitSize := uint(v.typ.Bits())
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trunc := (x << (64 - bitSize)) >> (64 - bitSize)
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return x != trunc
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}
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// StringHeader is the runtime representation of a string.
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type StringHeader struct {
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Data uintptr
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Len int
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}
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// StringValue represents a string value.
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type StringValue struct {
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value "string"
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}
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// Get returns the underlying string value.
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func (v *StringValue) Get() string { return *(*string)(v.addr) }
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// Set sets v to the value x.
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func (v *StringValue) Set(x string) {
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if !v.CanSet() {
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panic(cannotSet)
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}
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*(*string)(v.addr) = x
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}
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// Set sets v to the value x.
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func (v *StringValue) SetValue(x Value) { v.Set(x.(*StringValue).Get()) }
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// UintValue represents a uint value.
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type UintValue struct {
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value "uint"
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}
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// Get returns the underlying uuint value.
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func (v *UintValue) Get() uint64 {
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switch v.typ.Kind() {
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case Uint:
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return uint64(*(*uint)(v.addr))
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case Uint8:
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return uint64(*(*uint8)(v.addr))
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case Uint16:
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return uint64(*(*uint16)(v.addr))
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case Uint32:
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return uint64(*(*uint32)(v.addr))
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case Uint64:
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return *(*uint64)(v.addr)
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case Uintptr:
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return uint64(*(*uintptr)(v.addr))
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}
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panic("reflect: invalid uint kind")
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}
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// Set sets v to the value x.
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func (v *UintValue) Set(x uint64) {
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if !v.CanSet() {
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panic(cannotSet)
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}
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switch v.typ.Kind() {
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default:
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panic("reflect: invalid uint kind")
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case Uint:
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*(*uint)(v.addr) = uint(x)
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case Uint8:
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*(*uint8)(v.addr) = uint8(x)
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case Uint16:
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*(*uint16)(v.addr) = uint16(x)
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case Uint32:
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*(*uint32)(v.addr) = uint32(x)
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case Uint64:
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*(*uint64)(v.addr) = x
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case Uintptr:
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*(*uintptr)(v.addr) = uintptr(x)
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}
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}
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// Overflow returns true if x cannot be represented by the type of v.
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func (v *UintValue) Overflow(x uint64) bool {
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bitSize := uint(v.typ.Bits())
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trunc := (x << (64 - bitSize)) >> (64 - bitSize)
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return x != trunc
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}
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// Set sets v to the value x.
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func (v *UintValue) SetValue(x Value) { v.Set(x.(*UintValue).Get()) }
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// UnsafePointerValue represents an unsafe.Pointer value.
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type UnsafePointerValue struct {
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value "unsafe.Pointer"
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}
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// Get returns the underlying uintptr value.
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// Get returns uintptr, not unsafe.Pointer, so that
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// programs that do not import "unsafe" cannot
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// obtain a value of unsafe.Pointer type from "reflect".
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func (v *UnsafePointerValue) Get() uintptr { return uintptr(*(*unsafe.Pointer)(v.addr)) }
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// Set sets v to the value x.
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func (v *UnsafePointerValue) Set(x unsafe.Pointer) {
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if !v.CanSet() {
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panic(cannotSet)
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}
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*(*unsafe.Pointer)(v.addr) = x
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}
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// Set sets v to the value x.
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func (v *UnsafePointerValue) SetValue(x Value) {
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v.Set(unsafe.Pointer(x.(*UnsafePointerValue).Get()))
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}
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func typesMustMatch(t1, t2 Type) {
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if t1 != t2 {
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panic("type mismatch: " + t1.String() + " != " + t2.String())
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}
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}
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/*
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* array
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*/
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// ArrayOrSliceValue is the common interface
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// implemented by both ArrayValue and SliceValue.
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type ArrayOrSliceValue interface {
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Value
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Len() int
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Cap() int
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Elem(i int) Value
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addr() addr
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}
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// grow grows the slice s so that it can hold extra more values, allocating
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// more capacity if needed. It also returns the old and new slice lengths.
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func grow(s *SliceValue, extra int) (*SliceValue, int, int) {
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i0 := s.Len()
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i1 := i0 + extra
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if i1 < i0 {
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panic("append: slice overflow")
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}
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m := s.Cap()
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if i1 <= m {
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return s.Slice(0, i1), i0, i1
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}
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if m == 0 {
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m = extra
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} else {
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for m < i1 {
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if i0 < 1024 {
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m += m
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} else {
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m += m / 4
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}
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}
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}
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t := MakeSlice(s.Type().(*SliceType), i1, m)
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Copy(t, s)
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return t, i0, i1
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}
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// Append appends the values x to a slice s and returns the resulting slice.
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// Each x must have the same type as s' element type.
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func Append(s *SliceValue, x ...Value) *SliceValue {
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s, i0, i1 := grow(s, len(x))
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for i, j := i0, 0; i < i1; i, j = i+1, j+1 {
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s.Elem(i).SetValue(x[j])
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}
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return s
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}
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// AppendSlice appends a slice t to a slice s and returns the resulting slice.
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// The slices s and t must have the same element type.
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func AppendSlice(s, t *SliceValue) *SliceValue {
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s, i0, i1 := grow(s, t.Len())
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Copy(s.Slice(i0, i1), t)
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return s
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}
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// Copy copies the contents of src into dst until either
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// dst has been filled or src has been exhausted.
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// It returns the number of elements copied.
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// The arrays dst and src must have the same element type.
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func Copy(dst, src ArrayOrSliceValue) int {
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// TODO: This will have to move into the runtime
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// once the real gc goes in.
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de := dst.Type().(ArrayOrSliceType).Elem()
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se := src.Type().(ArrayOrSliceType).Elem()
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typesMustMatch(de, se)
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n := dst.Len()
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if xn := src.Len(); n > xn {
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n = xn
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}
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memmove(dst.addr(), src.addr(), uintptr(n)*de.Size())
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return n
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}
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// An ArrayValue represents an array.
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type ArrayValue struct {
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value "array"
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}
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// Len returns the length of the array.
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func (v *ArrayValue) Len() int { return v.typ.(*ArrayType).Len() }
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// Cap returns the capacity of the array (equal to Len()).
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func (v *ArrayValue) Cap() int { return v.typ.(*ArrayType).Len() }
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// addr returns the base address of the data in the array.
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func (v *ArrayValue) addr() addr { return v.value.addr }
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// Set assigns x to v.
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// The new value x must have the same type as v.
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func (v *ArrayValue) Set(x *ArrayValue) {
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if !v.CanSet() {
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panic(cannotSet)
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}
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typesMustMatch(v.typ, x.typ)
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Copy(v, x)
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}
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// Set sets v to the value x.
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func (v *ArrayValue) SetValue(x Value) { v.Set(x.(*ArrayValue)) }
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// Elem returns the i'th element of v.
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func (v *ArrayValue) Elem(i int) Value {
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typ := v.typ.(*ArrayType).Elem()
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n := v.Len()
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if i < 0 || i >= n {
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panic("array index out of bounds")
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}
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p := addr(uintptr(v.addr()) + uintptr(i)*typ.Size())
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return newValue(typ, p, v.flag)
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}
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/*
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* slice
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*/
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|
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// runtime representation of slice
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type SliceHeader struct {
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Data uintptr
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Len int
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Cap int
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}
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|
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// A SliceValue represents a slice.
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type SliceValue struct {
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value "slice"
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}
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|
|
func (v *SliceValue) slice() *SliceHeader { return (*SliceHeader)(v.value.addr) }
|
|
|
|
// IsNil returns whether v is a nil slice.
|
|
func (v *SliceValue) IsNil() bool { return v.slice().Data == 0 }
|
|
|
|
// Len returns the length of the slice.
|
|
func (v *SliceValue) Len() int { return int(v.slice().Len) }
|
|
|
|
// Cap returns the capacity of the slice.
|
|
func (v *SliceValue) Cap() int { return int(v.slice().Cap) }
|
|
|
|
// addr returns the base address of the data in the slice.
|
|
func (v *SliceValue) addr() addr { return addr(v.slice().Data) }
|
|
|
|
// SetLen changes the length of v.
|
|
// The new length n must be between 0 and the capacity, inclusive.
|
|
func (v *SliceValue) SetLen(n int) {
|
|
s := v.slice()
|
|
if n < 0 || n > int(s.Cap) {
|
|
panic("reflect: slice length out of range in SetLen")
|
|
}
|
|
s.Len = n
|
|
}
|
|
|
|
// Set assigns x to v.
|
|
// The new value x must have the same type as v.
|
|
func (v *SliceValue) Set(x *SliceValue) {
|
|
if !v.CanSet() {
|
|
panic(cannotSet)
|
|
}
|
|
typesMustMatch(v.typ, x.typ)
|
|
*v.slice() = *x.slice()
|
|
}
|
|
|
|
// Set sets v to the value x.
|
|
func (v *SliceValue) SetValue(x Value) { v.Set(x.(*SliceValue)) }
|
|
|
|
// Get returns the uintptr address of the v.Cap()'th element. This gives
|
|
// the same result for all slices of the same array.
|
|
// It is mainly useful for printing.
|
|
func (v *SliceValue) Get() uintptr {
|
|
typ := v.typ.(*SliceType)
|
|
return uintptr(v.addr()) + uintptr(v.Cap())*typ.Elem().Size()
|
|
}
|
|
|
|
// Slice returns a sub-slice of the slice v.
|
|
func (v *SliceValue) Slice(beg, end int) *SliceValue {
|
|
cap := v.Cap()
|
|
if beg < 0 || end < beg || end > cap {
|
|
panic("slice index out of bounds")
|
|
}
|
|
typ := v.typ.(*SliceType)
|
|
s := new(SliceHeader)
|
|
s.Data = uintptr(v.addr()) + uintptr(beg)*typ.Elem().Size()
|
|
s.Len = end - beg
|
|
s.Cap = cap - beg
|
|
|
|
// Like the result of Addr, we treat Slice as an
|
|
// unaddressable temporary, so don't set canAddr.
|
|
flag := canSet
|
|
if v.flag&canStore != 0 {
|
|
flag |= canStore
|
|
}
|
|
return newValue(typ, addr(s), flag).(*SliceValue)
|
|
}
|
|
|
|
// Elem returns the i'th element of v.
|
|
func (v *SliceValue) Elem(i int) Value {
|
|
typ := v.typ.(*SliceType).Elem()
|
|
n := v.Len()
|
|
if i < 0 || i >= n {
|
|
panic("reflect: slice index out of range")
|
|
}
|
|
p := addr(uintptr(v.addr()) + uintptr(i)*typ.Size())
|
|
flag := canAddr
|
|
if v.flag&canStore != 0 {
|
|
flag |= canSet | canStore
|
|
}
|
|
return newValue(typ, p, flag)
|
|
}
|
|
|
|
// MakeSlice creates a new zero-initialized slice value
|
|
// for the specified slice type, length, and capacity.
|
|
func MakeSlice(typ *SliceType, len, cap int) *SliceValue {
|
|
s := &SliceHeader{
|
|
Data: uintptr(unsafe.NewArray(typ.Elem(), cap)),
|
|
Len: len,
|
|
Cap: cap,
|
|
}
|
|
return newValue(typ, addr(s), canAddr|canSet|canStore).(*SliceValue)
|
|
}
|
|
|
|
/*
|
|
* chan
|
|
*/
|
|
|
|
// A ChanValue represents a chan.
|
|
type ChanValue struct {
|
|
value "chan"
|
|
}
|
|
|
|
// IsNil returns whether v is a nil channel.
|
|
func (v *ChanValue) IsNil() bool { return *(*uintptr)(v.addr) == 0 }
|
|
|
|
// Set assigns x to v.
|
|
// The new value x must have the same type as v.
|
|
func (v *ChanValue) Set(x *ChanValue) {
|
|
if !v.CanSet() {
|
|
panic(cannotSet)
|
|
}
|
|
typesMustMatch(v.typ, x.typ)
|
|
*(*uintptr)(v.addr) = *(*uintptr)(x.addr)
|
|
}
|
|
|
|
// Set sets v to the value x.
|
|
func (v *ChanValue) SetValue(x Value) { v.Set(x.(*ChanValue)) }
|
|
|
|
// Get returns the uintptr value of v.
|
|
// It is mainly useful for printing.
|
|
func (v *ChanValue) Get() uintptr { return *(*uintptr)(v.addr) }
|
|
|
|
// implemented in ../pkg/runtime/reflect.cgo
|
|
func makechan(typ *runtime.ChanType, size uint32) (ch *byte)
|
|
func chansend(ch, val *byte, selected *bool)
|
|
func chanrecv(ch, val *byte, selected *bool, ok *bool)
|
|
func chanclose(ch *byte)
|
|
func chanlen(ch *byte) int32
|
|
func chancap(ch *byte) int32
|
|
|
|
// Close closes the channel.
|
|
func (v *ChanValue) Close() {
|
|
ch := *(**byte)(v.addr)
|
|
chanclose(ch)
|
|
}
|
|
|
|
func (v *ChanValue) Len() int {
|
|
ch := *(**byte)(v.addr)
|
|
return int(chanlen(ch))
|
|
}
|
|
|
|
func (v *ChanValue) Cap() int {
|
|
ch := *(**byte)(v.addr)
|
|
return int(chancap(ch))
|
|
}
|
|
|
|
// internal send; non-blocking if selected != nil
|
|
func (v *ChanValue) send(x Value, selected *bool) {
|
|
t := v.Type().(*ChanType)
|
|
if t.Dir()&SendDir == 0 {
|
|
panic("send on recv-only channel")
|
|
}
|
|
typesMustMatch(t.Elem(), x.Type())
|
|
ch := *(**byte)(v.addr)
|
|
chansend(ch, (*byte)(x.getAddr()), selected)
|
|
}
|
|
|
|
// internal recv; non-blocking if selected != nil
|
|
func (v *ChanValue) recv(selected *bool) (Value, bool) {
|
|
t := v.Type().(*ChanType)
|
|
if t.Dir()&RecvDir == 0 {
|
|
panic("recv on send-only channel")
|
|
}
|
|
ch := *(**byte)(v.addr)
|
|
x := MakeZero(t.Elem())
|
|
var ok bool
|
|
chanrecv(ch, (*byte)(x.getAddr()), selected, &ok)
|
|
return x, ok
|
|
}
|
|
|
|
// Send sends x on the channel v.
|
|
func (v *ChanValue) Send(x Value) { v.send(x, nil) }
|
|
|
|
// Recv receives and returns a value from the channel v.
|
|
// The receive blocks until a value is ready.
|
|
// The boolean value ok is true if the value x corresponds to a send
|
|
// on the channel, false if it is a zero value received because the channel is closed.
|
|
func (v *ChanValue) Recv() (x Value, ok bool) {
|
|
return v.recv(nil)
|
|
}
|
|
|
|
// TrySend attempts to sends x on the channel v but will not block.
|
|
// It returns true if the value was sent, false otherwise.
|
|
func (v *ChanValue) TrySend(x Value) bool {
|
|
var selected bool
|
|
v.send(x, &selected)
|
|
return selected
|
|
}
|
|
|
|
// TryRecv attempts to receive a value from the channel v but will not block.
|
|
// If the receive cannot finish without blocking, TryRecv instead returns x == nil.
|
|
// If the receive can finish without blocking, TryRecv returns x != nil.
|
|
// The boolean value ok is true if the value x corresponds to a send
|
|
// on the channel, false if it is a zero value received because the channel is closed.
|
|
func (v *ChanValue) TryRecv() (x Value, ok bool) {
|
|
var selected bool
|
|
x, ok = v.recv(&selected)
|
|
if !selected {
|
|
return nil, false
|
|
}
|
|
return x, ok
|
|
}
|
|
|
|
// MakeChan creates a new channel with the specified type and buffer size.
|
|
func MakeChan(typ *ChanType, buffer int) *ChanValue {
|
|
if buffer < 0 {
|
|
panic("MakeChan: negative buffer size")
|
|
}
|
|
if typ.Dir() != BothDir {
|
|
panic("MakeChan: unidirectional channel type")
|
|
}
|
|
v := MakeZero(typ).(*ChanValue)
|
|
*(**byte)(v.addr) = makechan((*runtime.ChanType)(unsafe.Pointer(typ)), uint32(buffer))
|
|
return v
|
|
}
|
|
|
|
/*
|
|
* func
|
|
*/
|
|
|
|
// A FuncValue represents a function value.
|
|
type FuncValue struct {
|
|
value "func"
|
|
first *value
|
|
isInterface bool
|
|
}
|
|
|
|
// IsNil returns whether v is a nil function.
|
|
func (v *FuncValue) IsNil() bool { return *(*uintptr)(v.addr) == 0 }
|
|
|
|
// Get returns the uintptr value of v.
|
|
// It is mainly useful for printing.
|
|
func (v *FuncValue) Get() uintptr { return *(*uintptr)(v.addr) }
|
|
|
|
// Set assigns x to v.
|
|
// The new value x must have the same type as v.
|
|
func (v *FuncValue) Set(x *FuncValue) {
|
|
if !v.CanSet() {
|
|
panic(cannotSet)
|
|
}
|
|
typesMustMatch(v.typ, x.typ)
|
|
*(*uintptr)(v.addr) = *(*uintptr)(x.addr)
|
|
}
|
|
|
|
// Set sets v to the value x.
|
|
func (v *FuncValue) SetValue(x Value) { v.Set(x.(*FuncValue)) }
|
|
|
|
// Method returns a FuncValue corresponding to v's i'th method.
|
|
// The arguments to a Call on the returned FuncValue
|
|
// should not include a receiver; the FuncValue will use v
|
|
// as the receiver.
|
|
func (v *value) Method(i int) *FuncValue {
|
|
t := v.Type().uncommon()
|
|
if t == nil || i < 0 || i >= len(t.methods) {
|
|
return nil
|
|
}
|
|
p := &t.methods[i]
|
|
fn := p.tfn
|
|
fv := &FuncValue{value: value{runtimeToType(p.typ), addr(&fn), 0}, first: v, isInterface: false}
|
|
return fv
|
|
}
|
|
|
|
// implemented in ../pkg/runtime/*/asm.s
|
|
func call(typ *FuncType, fnaddr *byte, isInterface bool, params *addr, results *addr)
|
|
|
|
// Interface returns the fv as an interface value.
|
|
// If fv is a method obtained by invoking Value.Method
|
|
// (as opposed to Type.Method), Interface cannot return an
|
|
// interface value, so it panics.
|
|
func (fv *FuncValue) Interface() interface{} {
|
|
if fv.first != nil {
|
|
panic("FuncValue: cannot create interface value for method with bound receiver")
|
|
}
|
|
return fv.value.Interface()
|
|
}
|
|
|
|
// Call calls the function fv with input parameters in.
|
|
// It returns the function's output parameters as Values.
|
|
func (fv *FuncValue) Call(in []Value) []Value {
|
|
t := fv.Type().(*FuncType)
|
|
nin := len(in)
|
|
if fv.first != nil && !fv.isInterface {
|
|
nin++
|
|
}
|
|
if nin != t.NumIn() {
|
|
panic("FuncValue: wrong argument count")
|
|
}
|
|
if fv.first != nil && fv.isInterface {
|
|
nin++
|
|
}
|
|
nout := t.NumOut()
|
|
|
|
params := make([]addr, nin)
|
|
delta := 0
|
|
off := 0
|
|
if v := fv.first; v != nil {
|
|
// Hard-wired first argument.
|
|
if fv.isInterface {
|
|
// v is a single uninterpreted word
|
|
params[0] = v.getAddr()
|
|
} else {
|
|
// v is a real value
|
|
tv := v.Type()
|
|
|
|
// This is a method, so we need to always pass
|
|
// a pointer.
|
|
vAddr := v.getAddr()
|
|
if ptv, ok := tv.(*PtrType); ok {
|
|
typesMustMatch(t.In(0), tv)
|
|
} else {
|
|
p := addr(new(addr))
|
|
*(*addr)(p) = vAddr
|
|
vAddr = p
|
|
typesMustMatch(t.In(0).(*PtrType).Elem(), tv)
|
|
}
|
|
|
|
params[0] = vAddr
|
|
delta = 1
|
|
}
|
|
off = 1
|
|
}
|
|
for i, v := range in {
|
|
tv := v.Type()
|
|
tf := t.In(i + delta)
|
|
|
|
// If this is really a method, and we are explicitly
|
|
// passing the object, then we need to pass the address
|
|
// of the object instead. Unfortunately, we don't
|
|
// have any way to know that this is a method, so we just
|
|
// check the type. FIXME: This is ugly.
|
|
vAddr := v.getAddr()
|
|
if i == 0 && tf != tv {
|
|
if ptf, ok := tf.(*PtrType); ok {
|
|
p := addr(new(addr))
|
|
*(*addr)(p) = vAddr
|
|
vAddr = p
|
|
tf = ptf.Elem()
|
|
}
|
|
}
|
|
|
|
typesMustMatch(tf, tv)
|
|
params[i+off] = vAddr
|
|
}
|
|
|
|
ret := make([]Value, nout)
|
|
results := make([]addr, nout)
|
|
for i := 0; i < nout; i++ {
|
|
tv := t.Out(i)
|
|
v := MakeZero(tv)
|
|
results[i] = v.getAddr()
|
|
ret[i] = v
|
|
}
|
|
|
|
call(t, *(**byte)(fv.addr), fv.isInterface, ¶ms[0], &results[0])
|
|
|
|
return ret
|
|
}
|
|
|
|
/*
|
|
* interface
|
|
*/
|
|
|
|
// An InterfaceValue represents an interface value.
|
|
type InterfaceValue struct {
|
|
value "interface"
|
|
}
|
|
|
|
// IsNil returns whether v is a nil interface value.
|
|
func (v *InterfaceValue) IsNil() bool { return v.Interface() == nil }
|
|
|
|
// No single uinptr Get because v.Interface() is available.
|
|
|
|
// Get returns the two words that represent an interface in the runtime.
|
|
// Those words are useful only when playing unsafe games.
|
|
func (v *InterfaceValue) Get() [2]uintptr {
|
|
return *(*[2]uintptr)(v.addr)
|
|
}
|
|
|
|
// Elem returns the concrete value stored in the interface value v.
|
|
func (v *InterfaceValue) Elem() Value { return NewValue(v.Interface()) }
|
|
|
|
// ../runtime/reflect.cgo
|
|
func setiface(typ *InterfaceType, x *interface{}, addr addr)
|
|
|
|
// Set assigns x to v.
|
|
func (v *InterfaceValue) Set(x Value) {
|
|
var i interface{}
|
|
if x != nil {
|
|
i = x.Interface()
|
|
}
|
|
if !v.CanSet() {
|
|
panic(cannotSet)
|
|
}
|
|
// Two different representations; see comment in Get.
|
|
// Empty interface is easy.
|
|
t := v.typ.(*InterfaceType)
|
|
if t.NumMethod() == 0 {
|
|
*(*interface{})(v.addr) = i
|
|
return
|
|
}
|
|
|
|
// Non-empty interface requires a runtime check.
|
|
setiface(t, &i, v.addr)
|
|
}
|
|
|
|
// Set sets v to the value x.
|
|
func (v *InterfaceValue) SetValue(x Value) { v.Set(x) }
|
|
|
|
// Method returns a FuncValue corresponding to v's i'th method.
|
|
// The arguments to a Call on the returned FuncValue
|
|
// should not include a receiver; the FuncValue will use v
|
|
// as the receiver.
|
|
func (v *InterfaceValue) Method(i int) *FuncValue {
|
|
t := v.Type().(*InterfaceType)
|
|
if t == nil || i < 0 || i >= len(t.methods) {
|
|
return nil
|
|
}
|
|
p := &t.methods[i]
|
|
|
|
// Interface is two words: itable, data.
|
|
tab := *(**[10000]addr)(v.addr)
|
|
data := &value{Typeof((*byte)(nil)), addr(uintptr(v.addr) + ptrSize), 0}
|
|
|
|
fn := tab[i+1]
|
|
fv := &FuncValue{value: value{runtimeToType(p.typ), addr(&fn), 0}, first: data, isInterface: true}
|
|
return fv
|
|
}
|
|
|
|
/*
|
|
* map
|
|
*/
|
|
|
|
// A MapValue represents a map value.
|
|
type MapValue struct {
|
|
value "map"
|
|
}
|
|
|
|
// IsNil returns whether v is a nil map value.
|
|
func (v *MapValue) IsNil() bool { return *(*uintptr)(v.addr) == 0 }
|
|
|
|
// Set assigns x to v.
|
|
// The new value x must have the same type as v.
|
|
func (v *MapValue) Set(x *MapValue) {
|
|
if !v.CanSet() {
|
|
panic(cannotSet)
|
|
}
|
|
if x == nil {
|
|
*(**uintptr)(v.addr) = nil
|
|
return
|
|
}
|
|
typesMustMatch(v.typ, x.typ)
|
|
*(*uintptr)(v.addr) = *(*uintptr)(x.addr)
|
|
}
|
|
|
|
// Set sets v to the value x.
|
|
func (v *MapValue) SetValue(x Value) {
|
|
if x == nil {
|
|
v.Set(nil)
|
|
return
|
|
}
|
|
v.Set(x.(*MapValue))
|
|
}
|
|
|
|
// Get returns the uintptr value of v.
|
|
// It is mainly useful for printing.
|
|
func (v *MapValue) Get() uintptr { return *(*uintptr)(v.addr) }
|
|
|
|
// implemented in ../pkg/runtime/reflect.cgo
|
|
func mapaccess(m, key, val *byte) bool
|
|
func mapassign(m, key, val *byte)
|
|
func maplen(m *byte) int32
|
|
func mapiterinit(m *byte) *byte
|
|
func mapiternext(it *byte)
|
|
func mapiterkey(it *byte, key *byte) bool
|
|
func makemap(t *runtime.MapType) *byte
|
|
|
|
// Elem returns the value associated with key in the map v.
|
|
// It returns nil if key is not found in the map.
|
|
func (v *MapValue) Elem(key Value) Value {
|
|
t := v.Type().(*MapType)
|
|
typesMustMatch(t.Key(), key.Type())
|
|
m := *(**byte)(v.addr)
|
|
if m == nil {
|
|
return nil
|
|
}
|
|
newval := MakeZero(t.Elem())
|
|
if !mapaccess(m, (*byte)(key.getAddr()), (*byte)(newval.getAddr())) {
|
|
return nil
|
|
}
|
|
return newval
|
|
}
|
|
|
|
// SetElem sets the value associated with key in the map v to val.
|
|
// If val is nil, Put deletes the key from map.
|
|
func (v *MapValue) SetElem(key, val Value) {
|
|
t := v.Type().(*MapType)
|
|
typesMustMatch(t.Key(), key.Type())
|
|
var vaddr *byte
|
|
if val != nil {
|
|
typesMustMatch(t.Elem(), val.Type())
|
|
vaddr = (*byte)(val.getAddr())
|
|
}
|
|
m := *(**byte)(v.addr)
|
|
mapassign(m, (*byte)(key.getAddr()), vaddr)
|
|
}
|
|
|
|
// Len returns the number of keys in the map v.
|
|
func (v *MapValue) Len() int {
|
|
m := *(**byte)(v.addr)
|
|
if m == nil {
|
|
return 0
|
|
}
|
|
return int(maplen(m))
|
|
}
|
|
|
|
// Keys returns a slice containing all the keys present in the map,
|
|
// in unspecified order.
|
|
func (v *MapValue) Keys() []Value {
|
|
tk := v.Type().(*MapType).Key()
|
|
m := *(**byte)(v.addr)
|
|
mlen := int32(0)
|
|
if m != nil {
|
|
mlen = maplen(m)
|
|
}
|
|
it := mapiterinit(m)
|
|
a := make([]Value, mlen)
|
|
var i int
|
|
for i = 0; i < len(a); i++ {
|
|
k := MakeZero(tk)
|
|
if !mapiterkey(it, (*byte)(k.getAddr())) {
|
|
break
|
|
}
|
|
a[i] = k
|
|
mapiternext(it)
|
|
}
|
|
return a[0:i]
|
|
}
|
|
|
|
// MakeMap creates a new map of the specified type.
|
|
func MakeMap(typ *MapType) *MapValue {
|
|
v := MakeZero(typ).(*MapValue)
|
|
*(**byte)(v.addr) = makemap((*runtime.MapType)(unsafe.Pointer(typ)))
|
|
return v
|
|
}
|
|
|
|
/*
|
|
* ptr
|
|
*/
|
|
|
|
// A PtrValue represents a pointer.
|
|
type PtrValue struct {
|
|
value "ptr"
|
|
}
|
|
|
|
// IsNil returns whether v is a nil pointer.
|
|
func (v *PtrValue) IsNil() bool { return *(*uintptr)(v.addr) == 0 }
|
|
|
|
// Get returns the uintptr value of v.
|
|
// It is mainly useful for printing.
|
|
func (v *PtrValue) Get() uintptr { return *(*uintptr)(v.addr) }
|
|
|
|
// Set assigns x to v.
|
|
// The new value x must have the same type as v, and x.Elem().CanSet() must be true.
|
|
func (v *PtrValue) Set(x *PtrValue) {
|
|
if x == nil {
|
|
*(**uintptr)(v.addr) = nil
|
|
return
|
|
}
|
|
if !v.CanSet() {
|
|
panic(cannotSet)
|
|
}
|
|
if x.flag&canStore == 0 {
|
|
panic("cannot copy pointer obtained from unexported struct field")
|
|
}
|
|
typesMustMatch(v.typ, x.typ)
|
|
// TODO: This will have to move into the runtime
|
|
// once the new gc goes in
|
|
*(*uintptr)(v.addr) = *(*uintptr)(x.addr)
|
|
}
|
|
|
|
// Set sets v to the value x.
|
|
func (v *PtrValue) SetValue(x Value) {
|
|
if x == nil {
|
|
v.Set(nil)
|
|
return
|
|
}
|
|
v.Set(x.(*PtrValue))
|
|
}
|
|
|
|
// PointTo changes v to point to x.
|
|
// If x is a nil Value, PointTo sets v to nil.
|
|
func (v *PtrValue) PointTo(x Value) {
|
|
if x == nil {
|
|
*(**uintptr)(v.addr) = nil
|
|
return
|
|
}
|
|
if !x.CanSet() {
|
|
panic("cannot set x; cannot point to x")
|
|
}
|
|
typesMustMatch(v.typ.(*PtrType).Elem(), x.Type())
|
|
// TODO: This will have to move into the runtime
|
|
// once the new gc goes in.
|
|
*(*uintptr)(v.addr) = x.UnsafeAddr()
|
|
}
|
|
|
|
// Elem returns the value that v points to.
|
|
// If v is a nil pointer, Elem returns a nil Value.
|
|
func (v *PtrValue) Elem() Value {
|
|
if v.IsNil() {
|
|
return nil
|
|
}
|
|
flag := canAddr
|
|
if v.flag&canStore != 0 {
|
|
flag |= canSet | canStore
|
|
}
|
|
return newValue(v.typ.(*PtrType).Elem(), *(*addr)(v.addr), flag)
|
|
}
|
|
|
|
// Indirect returns the value that v points to.
|
|
// If v is a nil pointer, Indirect returns a nil Value.
|
|
// If v is not a pointer, Indirect returns v.
|
|
func Indirect(v Value) Value {
|
|
if pv, ok := v.(*PtrValue); ok {
|
|
return pv.Elem()
|
|
}
|
|
return v
|
|
}
|
|
|
|
/*
|
|
* struct
|
|
*/
|
|
|
|
// A StructValue represents a struct value.
|
|
type StructValue struct {
|
|
value "struct"
|
|
}
|
|
|
|
// Set assigns x to v.
|
|
// The new value x must have the same type as v.
|
|
func (v *StructValue) Set(x *StructValue) {
|
|
// TODO: This will have to move into the runtime
|
|
// once the gc goes in.
|
|
if !v.CanSet() {
|
|
panic(cannotSet)
|
|
}
|
|
typesMustMatch(v.typ, x.typ)
|
|
memmove(v.addr, x.addr, v.typ.Size())
|
|
}
|
|
|
|
// Set sets v to the value x.
|
|
func (v *StructValue) SetValue(x Value) { v.Set(x.(*StructValue)) }
|
|
|
|
// Field returns the i'th field of the struct.
|
|
func (v *StructValue) Field(i int) Value {
|
|
t := v.typ.(*StructType)
|
|
if i < 0 || i >= t.NumField() {
|
|
return nil
|
|
}
|
|
f := t.Field(i)
|
|
flag := v.flag
|
|
if f.PkgPath != "" {
|
|
// unexported field
|
|
flag &^= canSet | canStore
|
|
}
|
|
return newValue(f.Type, addr(uintptr(v.addr)+f.Offset), flag)
|
|
}
|
|
|
|
// FieldByIndex returns the nested field corresponding to index.
|
|
func (t *StructValue) FieldByIndex(index []int) (v Value) {
|
|
v = t
|
|
for i, x := range index {
|
|
if i > 0 {
|
|
if p, ok := v.(*PtrValue); ok {
|
|
v = p.Elem()
|
|
}
|
|
if s, ok := v.(*StructValue); ok {
|
|
t = s
|
|
} else {
|
|
v = nil
|
|
return
|
|
}
|
|
}
|
|
v = t.Field(x)
|
|
}
|
|
return
|
|
}
|
|
|
|
// FieldByName returns the struct field with the given name.
|
|
// The result is nil if no field was found.
|
|
func (t *StructValue) FieldByName(name string) Value {
|
|
if f, ok := t.Type().(*StructType).FieldByName(name); ok {
|
|
return t.FieldByIndex(f.Index)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// FieldByNameFunc returns the struct field with a name that satisfies the
|
|
// match function.
|
|
// The result is nil if no field was found.
|
|
func (t *StructValue) FieldByNameFunc(match func(string) bool) Value {
|
|
if f, ok := t.Type().(*StructType).FieldByNameFunc(match); ok {
|
|
return t.FieldByIndex(f.Index)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// NumField returns the number of fields in the struct.
|
|
func (v *StructValue) NumField() int { return v.typ.(*StructType).NumField() }
|
|
|
|
/*
|
|
* constructors
|
|
*/
|
|
|
|
// NewValue returns a new Value initialized to the concrete value
|
|
// stored in the interface i. NewValue(nil) returns nil.
|
|
func NewValue(i interface{}) Value {
|
|
if i == nil {
|
|
return nil
|
|
}
|
|
t, a := unsafe.Reflect(i)
|
|
return newValue(canonicalize(toType(t)), addr(a), canSet|canAddr|canStore)
|
|
}
|
|
|
|
func newValue(typ Type, addr addr, flag uint32) Value {
|
|
v := value{typ, addr, flag}
|
|
switch typ.(type) {
|
|
case *ArrayType:
|
|
return &ArrayValue{v}
|
|
case *BoolType:
|
|
return &BoolValue{v}
|
|
case *ChanType:
|
|
return &ChanValue{v}
|
|
case *FloatType:
|
|
return &FloatValue{v}
|
|
case *FuncType:
|
|
return &FuncValue{value: v}
|
|
case *ComplexType:
|
|
return &ComplexValue{v}
|
|
case *IntType:
|
|
return &IntValue{v}
|
|
case *InterfaceType:
|
|
return &InterfaceValue{v}
|
|
case *MapType:
|
|
return &MapValue{v}
|
|
case *PtrType:
|
|
return &PtrValue{v}
|
|
case *SliceType:
|
|
return &SliceValue{v}
|
|
case *StringType:
|
|
return &StringValue{v}
|
|
case *StructType:
|
|
return &StructValue{v}
|
|
case *UintType:
|
|
return &UintValue{v}
|
|
case *UnsafePointerType:
|
|
return &UnsafePointerValue{v}
|
|
}
|
|
panic("newValue" + typ.String())
|
|
}
|
|
|
|
// MakeZero returns a zero Value for the specified Type.
|
|
func MakeZero(typ Type) Value {
|
|
if typ == nil {
|
|
return nil
|
|
}
|
|
return newValue(typ, addr(unsafe.New(typ)), canSet|canAddr|canStore)
|
|
}
|