blob: 088aa85d483d7b9b29c9c963efe37ce338fc330f (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
|
// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build !purego,!appengine
package impl
import (
"reflect"
"sync/atomic"
"unsafe"
)
const UnsafeEnabled = true
// Pointer is an opaque pointer type.
type Pointer unsafe.Pointer
// offset represents the offset to a struct field, accessible from a pointer.
// The offset is the byte offset to the field from the start of the struct.
type offset uintptr
// offsetOf returns a field offset for the struct field.
func offsetOf(f reflect.StructField, x exporter) offset {
return offset(f.Offset)
}
// IsValid reports whether the offset is valid.
func (f offset) IsValid() bool { return f != invalidOffset }
// invalidOffset is an invalid field offset.
var invalidOffset = ^offset(0)
// zeroOffset is a noop when calling pointer.Apply.
var zeroOffset = offset(0)
// pointer is a pointer to a message struct or field.
type pointer struct{ p unsafe.Pointer }
// pointerOf returns p as a pointer.
func pointerOf(p Pointer) pointer {
return pointer{p: unsafe.Pointer(p)}
}
// pointerOfValue returns v as a pointer.
func pointerOfValue(v reflect.Value) pointer {
return pointer{p: unsafe.Pointer(v.Pointer())}
}
// pointerOfIface returns the pointer portion of an interface.
func pointerOfIface(v interface{}) pointer {
type ifaceHeader struct {
Type unsafe.Pointer
Data unsafe.Pointer
}
return pointer{p: (*ifaceHeader)(unsafe.Pointer(&v)).Data}
}
// IsNil reports whether the pointer is nil.
func (p pointer) IsNil() bool {
return p.p == nil
}
// Apply adds an offset to the pointer to derive a new pointer
// to a specified field. The pointer must be valid and pointing at a struct.
func (p pointer) Apply(f offset) pointer {
if p.IsNil() {
panic("invalid nil pointer")
}
return pointer{p: unsafe.Pointer(uintptr(p.p) + uintptr(f))}
}
// AsValueOf treats p as a pointer to an object of type t and returns the value.
// It is equivalent to reflect.ValueOf(p.AsIfaceOf(t))
func (p pointer) AsValueOf(t reflect.Type) reflect.Value {
return reflect.NewAt(t, p.p)
}
// AsIfaceOf treats p as a pointer to an object of type t and returns the value.
// It is equivalent to p.AsValueOf(t).Interface()
func (p pointer) AsIfaceOf(t reflect.Type) interface{} {
// TODO: Use tricky unsafe magic to directly create ifaceHeader.
return p.AsValueOf(t).Interface()
}
func (p pointer) Bool() *bool { return (*bool)(p.p) }
func (p pointer) BoolPtr() **bool { return (**bool)(p.p) }
func (p pointer) BoolSlice() *[]bool { return (*[]bool)(p.p) }
func (p pointer) Int32() *int32 { return (*int32)(p.p) }
func (p pointer) Int32Ptr() **int32 { return (**int32)(p.p) }
func (p pointer) Int32Slice() *[]int32 { return (*[]int32)(p.p) }
func (p pointer) Int64() *int64 { return (*int64)(p.p) }
func (p pointer) Int64Ptr() **int64 { return (**int64)(p.p) }
func (p pointer) Int64Slice() *[]int64 { return (*[]int64)(p.p) }
func (p pointer) Uint32() *uint32 { return (*uint32)(p.p) }
func (p pointer) Uint32Ptr() **uint32 { return (**uint32)(p.p) }
func (p pointer) Uint32Slice() *[]uint32 { return (*[]uint32)(p.p) }
func (p pointer) Uint64() *uint64 { return (*uint64)(p.p) }
func (p pointer) Uint64Ptr() **uint64 { return (**uint64)(p.p) }
func (p pointer) Uint64Slice() *[]uint64 { return (*[]uint64)(p.p) }
func (p pointer) Float32() *float32 { return (*float32)(p.p) }
func (p pointer) Float32Ptr() **float32 { return (**float32)(p.p) }
func (p pointer) Float32Slice() *[]float32 { return (*[]float32)(p.p) }
func (p pointer) Float64() *float64 { return (*float64)(p.p) }
func (p pointer) Float64Ptr() **float64 { return (**float64)(p.p) }
func (p pointer) Float64Slice() *[]float64 { return (*[]float64)(p.p) }
func (p pointer) String() *string { return (*string)(p.p) }
func (p pointer) StringPtr() **string { return (**string)(p.p) }
func (p pointer) StringSlice() *[]string { return (*[]string)(p.p) }
func (p pointer) Bytes() *[]byte { return (*[]byte)(p.p) }
func (p pointer) BytesSlice() *[][]byte { return (*[][]byte)(p.p) }
func (p pointer) WeakFields() *weakFields { return (*weakFields)(p.p) }
func (p pointer) Extensions() *map[int32]ExtensionField { return (*map[int32]ExtensionField)(p.p) }
func (p pointer) Elem() pointer {
return pointer{p: *(*unsafe.Pointer)(p.p)}
}
// PointerSlice loads []*T from p as a []pointer.
// The value returned is aliased with the original slice.
// This behavior differs from the implementation in pointer_reflect.go.
func (p pointer) PointerSlice() []pointer {
// Super-tricky - p should point to a []*T where T is a
// message type. We load it as []pointer.
return *(*[]pointer)(p.p)
}
// AppendPointerSlice appends v to p, which must be a []*T.
func (p pointer) AppendPointerSlice(v pointer) {
*(*[]pointer)(p.p) = append(*(*[]pointer)(p.p), v)
}
// SetPointer sets *p to v.
func (p pointer) SetPointer(v pointer) {
*(*unsafe.Pointer)(p.p) = (unsafe.Pointer)(v.p)
}
// Static check that MessageState does not exceed the size of a pointer.
const _ = uint(unsafe.Sizeof(unsafe.Pointer(nil)) - unsafe.Sizeof(MessageState{}))
func (Export) MessageStateOf(p Pointer) *messageState {
// Super-tricky - see documentation on MessageState.
return (*messageState)(unsafe.Pointer(p))
}
func (ms *messageState) pointer() pointer {
// Super-tricky - see documentation on MessageState.
return pointer{p: unsafe.Pointer(ms)}
}
func (ms *messageState) messageInfo() *MessageInfo {
mi := ms.LoadMessageInfo()
if mi == nil {
panic("invalid nil message info; this suggests memory corruption due to a race or shallow copy on the message struct")
}
return mi
}
func (ms *messageState) LoadMessageInfo() *MessageInfo {
return (*MessageInfo)(atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(&ms.atomicMessageInfo))))
}
func (ms *messageState) StoreMessageInfo(mi *MessageInfo) {
atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(&ms.atomicMessageInfo)), unsafe.Pointer(mi))
}
type atomicNilMessage struct{ p unsafe.Pointer } // p is a *messageReflectWrapper
func (m *atomicNilMessage) Init(mi *MessageInfo) *messageReflectWrapper {
if p := atomic.LoadPointer(&m.p); p != nil {
return (*messageReflectWrapper)(p)
}
w := &messageReflectWrapper{mi: mi}
atomic.CompareAndSwapPointer(&m.p, nil, (unsafe.Pointer)(w))
return (*messageReflectWrapper)(atomic.LoadPointer(&m.p))
}
|
