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// Copyright 2018 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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// +build purego appengine |
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package impl |
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import ( |
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"fmt" |
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"reflect" |
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"sync" |
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) |
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const UnsafeEnabled = false |
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// Pointer is an opaque pointer type. |
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type Pointer interface{} |
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// offset represents the offset to a struct field, accessible from a pointer. |
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// The offset is the field index into a struct. |
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type offset struct { |
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index int |
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export exporter |
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} |
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// offsetOf returns a field offset for the struct field. |
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func offsetOf(f reflect.StructField, x exporter) offset { |
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if len(f.Index) != 1 { |
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panic("embedded structs are not supported") |
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} |
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if f.PkgPath == "" { |
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return offset{index: f.Index[0]} // field is already exported |
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} |
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if x == nil { |
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panic("exporter must be provided for unexported field") |
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} |
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return offset{index: f.Index[0], export: x} |
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} |
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// IsValid reports whether the offset is valid. |
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func (f offset) IsValid() bool { return f.index >= 0 } |
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// invalidOffset is an invalid field offset. |
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var invalidOffset = offset{index: -1} |
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// zeroOffset is a noop when calling pointer.Apply. |
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var zeroOffset = offset{index: 0} |
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// pointer is an abstract representation of a pointer to a struct or field. |
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type pointer struct{ v reflect.Value } |
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// pointerOf returns p as a pointer. |
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func pointerOf(p Pointer) pointer { |
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return pointerOfIface(p) |
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} |
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// pointerOfValue returns v as a pointer. |
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func pointerOfValue(v reflect.Value) pointer { |
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return pointer{v: v} |
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} |
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// pointerOfIface returns the pointer portion of an interface. |
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func pointerOfIface(v interface{}) pointer { |
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return pointer{v: reflect.ValueOf(v)} |
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} |
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// IsNil reports whether the pointer is nil. |
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func (p pointer) IsNil() bool { |
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return p.v.IsNil() |
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} |
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// Apply adds an offset to the pointer to derive a new pointer |
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// to a specified field. The current pointer must be pointing at a struct. |
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func (p pointer) Apply(f offset) pointer { |
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if f.export != nil { |
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if v := reflect.ValueOf(f.export(p.v.Interface(), f.index)); v.IsValid() { |
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return pointer{v: v} |
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} |
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} |
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return pointer{v: p.v.Elem().Field(f.index).Addr()} |
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} |
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// AsValueOf treats p as a pointer to an object of type t and returns the value. |
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// It is equivalent to reflect.ValueOf(p.AsIfaceOf(t)) |
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func (p pointer) AsValueOf(t reflect.Type) reflect.Value { |
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if got := p.v.Type().Elem(); got != t { |
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panic(fmt.Sprintf("invalid type: got %v, want %v", got, t)) |
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} |
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return p.v |
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} |
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// AsIfaceOf treats p as a pointer to an object of type t and returns the value. |
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// It is equivalent to p.AsValueOf(t).Interface() |
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func (p pointer) AsIfaceOf(t reflect.Type) interface{} { |
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return p.AsValueOf(t).Interface() |
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} |
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func (p pointer) Bool() *bool { return p.v.Interface().(*bool) } |
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func (p pointer) BoolPtr() **bool { return p.v.Interface().(**bool) } |
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func (p pointer) BoolSlice() *[]bool { return p.v.Interface().(*[]bool) } |
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func (p pointer) Int32() *int32 { return p.v.Interface().(*int32) } |
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func (p pointer) Int32Ptr() **int32 { return p.v.Interface().(**int32) } |
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func (p pointer) Int32Slice() *[]int32 { return p.v.Interface().(*[]int32) } |
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func (p pointer) Int64() *int64 { return p.v.Interface().(*int64) } |
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func (p pointer) Int64Ptr() **int64 { return p.v.Interface().(**int64) } |
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func (p pointer) Int64Slice() *[]int64 { return p.v.Interface().(*[]int64) } |
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func (p pointer) Uint32() *uint32 { return p.v.Interface().(*uint32) } |
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func (p pointer) Uint32Ptr() **uint32 { return p.v.Interface().(**uint32) } |
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func (p pointer) Uint32Slice() *[]uint32 { return p.v.Interface().(*[]uint32) } |
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func (p pointer) Uint64() *uint64 { return p.v.Interface().(*uint64) } |
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func (p pointer) Uint64Ptr() **uint64 { return p.v.Interface().(**uint64) } |
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func (p pointer) Uint64Slice() *[]uint64 { return p.v.Interface().(*[]uint64) } |
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func (p pointer) Float32() *float32 { return p.v.Interface().(*float32) } |
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func (p pointer) Float32Ptr() **float32 { return p.v.Interface().(**float32) } |
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func (p pointer) Float32Slice() *[]float32 { return p.v.Interface().(*[]float32) } |
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func (p pointer) Float64() *float64 { return p.v.Interface().(*float64) } |
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func (p pointer) Float64Ptr() **float64 { return p.v.Interface().(**float64) } |
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func (p pointer) Float64Slice() *[]float64 { return p.v.Interface().(*[]float64) } |
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func (p pointer) String() *string { return p.v.Interface().(*string) } |
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func (p pointer) StringPtr() **string { return p.v.Interface().(**string) } |
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func (p pointer) StringSlice() *[]string { return p.v.Interface().(*[]string) } |
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func (p pointer) Bytes() *[]byte { return p.v.Interface().(*[]byte) } |
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func (p pointer) BytesPtr() **[]byte { return p.v.Interface().(**[]byte) } |
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func (p pointer) BytesSlice() *[][]byte { return p.v.Interface().(*[][]byte) } |
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func (p pointer) WeakFields() *weakFields { return (*weakFields)(p.v.Interface().(*WeakFields)) } |
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func (p pointer) Extensions() *map[int32]ExtensionField { |
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return p.v.Interface().(*map[int32]ExtensionField) |
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} |
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func (p pointer) Elem() pointer { |
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return pointer{v: p.v.Elem()} |
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} |
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// PointerSlice copies []*T from p as a new []pointer. |
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// This behavior differs from the implementation in pointer_unsafe.go. |
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func (p pointer) PointerSlice() []pointer { |
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// TODO: reconsider this |
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if p.v.IsNil() { |
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return nil |
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} |
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n := p.v.Elem().Len() |
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s := make([]pointer, n) |
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for i := 0; i < n; i++ { |
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s[i] = pointer{v: p.v.Elem().Index(i)} |
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} |
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return s |
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} |
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// AppendPointerSlice appends v to p, which must be a []*T. |
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func (p pointer) AppendPointerSlice(v pointer) { |
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sp := p.v.Elem() |
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sp.Set(reflect.Append(sp, v.v)) |
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} |
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// SetPointer sets *p to v. |
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func (p pointer) SetPointer(v pointer) { |
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p.v.Elem().Set(v.v) |
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} |
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func (Export) MessageStateOf(p Pointer) *messageState { panic("not supported") } |
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func (ms *messageState) pointer() pointer { panic("not supported") } |
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func (ms *messageState) messageInfo() *MessageInfo { panic("not supported") } |
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func (ms *messageState) LoadMessageInfo() *MessageInfo { panic("not supported") } |
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func (ms *messageState) StoreMessageInfo(mi *MessageInfo) { panic("not supported") } |
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type atomicNilMessage struct { |
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once sync.Once |
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m messageReflectWrapper |
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} |
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func (m *atomicNilMessage) Init(mi *MessageInfo) *messageReflectWrapper { |
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m.once.Do(func() { |
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m.m.p = pointerOfIface(reflect.Zero(mi.GoReflectType).Interface()) |
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m.m.mi = mi |
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}) |
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return &m.m |
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} |