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Scott Bakere7144bc2019-10-01 14:16:47 -07001// Go support for Protocol Buffers - Google's data interchange format
2//
3// Copyright 2012 The Go Authors. All rights reserved.
4// https://github.com/golang/protobuf
5//
6// Redistribution and use in source and binary forms, with or without
7// modification, are permitted provided that the following conditions are
8// met:
9//
10// * Redistributions of source code must retain the above copyright
11// notice, this list of conditions and the following disclaimer.
12// * Redistributions in binary form must reproduce the above
13// copyright notice, this list of conditions and the following disclaimer
14// in the documentation and/or other materials provided with the
15// distribution.
16// * Neither the name of Google Inc. nor the names of its
17// contributors may be used to endorse or promote products derived from
18// this software without specific prior written permission.
19//
20// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31
32// +build purego appengine js
33
34// This file contains an implementation of proto field accesses using package reflect.
35// It is slower than the code in pointer_unsafe.go but it avoids package unsafe and can
36// be used on App Engine.
37
38package proto
39
40import (
41 "reflect"
42 "sync"
43)
44
45const unsafeAllowed = false
46
47// A field identifies a field in a struct, accessible from a pointer.
48// In this implementation, a field is identified by the sequence of field indices
49// passed to reflect's FieldByIndex.
50type field []int
51
52// toField returns a field equivalent to the given reflect field.
53func toField(f *reflect.StructField) field {
54 return f.Index
55}
56
57// invalidField is an invalid field identifier.
58var invalidField = field(nil)
59
60// zeroField is a noop when calling pointer.offset.
61var zeroField = field([]int{})
62
63// IsValid reports whether the field identifier is valid.
64func (f field) IsValid() bool { return f != nil }
65
66// The pointer type is for the table-driven decoder.
67// The implementation here uses a reflect.Value of pointer type to
68// create a generic pointer. In pointer_unsafe.go we use unsafe
69// instead of reflect to implement the same (but faster) interface.
70type pointer struct {
71 v reflect.Value
72}
73
74// toPointer converts an interface of pointer type to a pointer
75// that points to the same target.
76func toPointer(i *Message) pointer {
77 return pointer{v: reflect.ValueOf(*i)}
78}
79
80// toAddrPointer converts an interface to a pointer that points to
81// the interface data.
82func toAddrPointer(i *interface{}, isptr bool) pointer {
83 v := reflect.ValueOf(*i)
84 u := reflect.New(v.Type())
85 u.Elem().Set(v)
86 return pointer{v: u}
87}
88
89// valToPointer converts v to a pointer. v must be of pointer type.
90func valToPointer(v reflect.Value) pointer {
91 return pointer{v: v}
92}
93
94// offset converts from a pointer to a structure to a pointer to
95// one of its fields.
96func (p pointer) offset(f field) pointer {
97 return pointer{v: p.v.Elem().FieldByIndex(f).Addr()}
98}
99
100func (p pointer) isNil() bool {
101 return p.v.IsNil()
102}
103
104// grow updates the slice s in place to make it one element longer.
105// s must be addressable.
106// Returns the (addressable) new element.
107func grow(s reflect.Value) reflect.Value {
108 n, m := s.Len(), s.Cap()
109 if n < m {
110 s.SetLen(n + 1)
111 } else {
112 s.Set(reflect.Append(s, reflect.Zero(s.Type().Elem())))
113 }
114 return s.Index(n)
115}
116
117func (p pointer) toInt64() *int64 {
118 return p.v.Interface().(*int64)
119}
120func (p pointer) toInt64Ptr() **int64 {
121 return p.v.Interface().(**int64)
122}
123func (p pointer) toInt64Slice() *[]int64 {
124 return p.v.Interface().(*[]int64)
125}
126
127var int32ptr = reflect.TypeOf((*int32)(nil))
128
129func (p pointer) toInt32() *int32 {
130 return p.v.Convert(int32ptr).Interface().(*int32)
131}
132
133// The toInt32Ptr/Slice methods don't work because of enums.
134// Instead, we must use set/get methods for the int32ptr/slice case.
135/*
136 func (p pointer) toInt32Ptr() **int32 {
137 return p.v.Interface().(**int32)
138}
139 func (p pointer) toInt32Slice() *[]int32 {
140 return p.v.Interface().(*[]int32)
141}
142*/
143func (p pointer) getInt32Ptr() *int32 {
144 if p.v.Type().Elem().Elem() == reflect.TypeOf(int32(0)) {
145 // raw int32 type
146 return p.v.Elem().Interface().(*int32)
147 }
148 // an enum
149 return p.v.Elem().Convert(int32PtrType).Interface().(*int32)
150}
151func (p pointer) setInt32Ptr(v int32) {
152 // Allocate value in a *int32. Possibly convert that to a *enum.
153 // Then assign it to a **int32 or **enum.
154 // Note: we can convert *int32 to *enum, but we can't convert
155 // **int32 to **enum!
156 p.v.Elem().Set(reflect.ValueOf(&v).Convert(p.v.Type().Elem()))
157}
158
159// getInt32Slice copies []int32 from p as a new slice.
160// This behavior differs from the implementation in pointer_unsafe.go.
161func (p pointer) getInt32Slice() []int32 {
162 if p.v.Type().Elem().Elem() == reflect.TypeOf(int32(0)) {
163 // raw int32 type
164 return p.v.Elem().Interface().([]int32)
165 }
166 // an enum
167 // Allocate a []int32, then assign []enum's values into it.
168 // Note: we can't convert []enum to []int32.
169 slice := p.v.Elem()
170 s := make([]int32, slice.Len())
171 for i := 0; i < slice.Len(); i++ {
172 s[i] = int32(slice.Index(i).Int())
173 }
174 return s
175}
176
177// setInt32Slice copies []int32 into p as a new slice.
178// This behavior differs from the implementation in pointer_unsafe.go.
179func (p pointer) setInt32Slice(v []int32) {
180 if p.v.Type().Elem().Elem() == reflect.TypeOf(int32(0)) {
181 // raw int32 type
182 p.v.Elem().Set(reflect.ValueOf(v))
183 return
184 }
185 // an enum
186 // Allocate a []enum, then assign []int32's values into it.
187 // Note: we can't convert []enum to []int32.
188 slice := reflect.MakeSlice(p.v.Type().Elem(), len(v), cap(v))
189 for i, x := range v {
190 slice.Index(i).SetInt(int64(x))
191 }
192 p.v.Elem().Set(slice)
193}
194func (p pointer) appendInt32Slice(v int32) {
195 grow(p.v.Elem()).SetInt(int64(v))
196}
197
198func (p pointer) toUint64() *uint64 {
199 return p.v.Interface().(*uint64)
200}
201func (p pointer) toUint64Ptr() **uint64 {
202 return p.v.Interface().(**uint64)
203}
204func (p pointer) toUint64Slice() *[]uint64 {
205 return p.v.Interface().(*[]uint64)
206}
207func (p pointer) toUint32() *uint32 {
208 return p.v.Interface().(*uint32)
209}
210func (p pointer) toUint32Ptr() **uint32 {
211 return p.v.Interface().(**uint32)
212}
213func (p pointer) toUint32Slice() *[]uint32 {
214 return p.v.Interface().(*[]uint32)
215}
216func (p pointer) toBool() *bool {
217 return p.v.Interface().(*bool)
218}
219func (p pointer) toBoolPtr() **bool {
220 return p.v.Interface().(**bool)
221}
222func (p pointer) toBoolSlice() *[]bool {
223 return p.v.Interface().(*[]bool)
224}
225func (p pointer) toFloat64() *float64 {
226 return p.v.Interface().(*float64)
227}
228func (p pointer) toFloat64Ptr() **float64 {
229 return p.v.Interface().(**float64)
230}
231func (p pointer) toFloat64Slice() *[]float64 {
232 return p.v.Interface().(*[]float64)
233}
234func (p pointer) toFloat32() *float32 {
235 return p.v.Interface().(*float32)
236}
237func (p pointer) toFloat32Ptr() **float32 {
238 return p.v.Interface().(**float32)
239}
240func (p pointer) toFloat32Slice() *[]float32 {
241 return p.v.Interface().(*[]float32)
242}
243func (p pointer) toString() *string {
244 return p.v.Interface().(*string)
245}
246func (p pointer) toStringPtr() **string {
247 return p.v.Interface().(**string)
248}
249func (p pointer) toStringSlice() *[]string {
250 return p.v.Interface().(*[]string)
251}
252func (p pointer) toBytes() *[]byte {
253 return p.v.Interface().(*[]byte)
254}
255func (p pointer) toBytesSlice() *[][]byte {
256 return p.v.Interface().(*[][]byte)
257}
258func (p pointer) toExtensions() *XXX_InternalExtensions {
259 return p.v.Interface().(*XXX_InternalExtensions)
260}
261func (p pointer) toOldExtensions() *map[int32]Extension {
262 return p.v.Interface().(*map[int32]Extension)
263}
264func (p pointer) getPointer() pointer {
265 return pointer{v: p.v.Elem()}
266}
267func (p pointer) setPointer(q pointer) {
268 p.v.Elem().Set(q.v)
269}
270func (p pointer) appendPointer(q pointer) {
271 grow(p.v.Elem()).Set(q.v)
272}
273
274// getPointerSlice copies []*T from p as a new []pointer.
275// This behavior differs from the implementation in pointer_unsafe.go.
276func (p pointer) getPointerSlice() []pointer {
277 if p.v.IsNil() {
278 return nil
279 }
280 n := p.v.Elem().Len()
281 s := make([]pointer, n)
282 for i := 0; i < n; i++ {
283 s[i] = pointer{v: p.v.Elem().Index(i)}
284 }
285 return s
286}
287
288// setPointerSlice copies []pointer into p as a new []*T.
289// This behavior differs from the implementation in pointer_unsafe.go.
290func (p pointer) setPointerSlice(v []pointer) {
291 if v == nil {
292 p.v.Elem().Set(reflect.New(p.v.Elem().Type()).Elem())
293 return
294 }
295 s := reflect.MakeSlice(p.v.Elem().Type(), 0, len(v))
296 for _, p := range v {
297 s = reflect.Append(s, p.v)
298 }
299 p.v.Elem().Set(s)
300}
301
302// getInterfacePointer returns a pointer that points to the
303// interface data of the interface pointed by p.
304func (p pointer) getInterfacePointer() pointer {
305 if p.v.Elem().IsNil() {
306 return pointer{v: p.v.Elem()}
307 }
308 return pointer{v: p.v.Elem().Elem().Elem().Field(0).Addr()} // *interface -> interface -> *struct -> struct
309}
310
311func (p pointer) asPointerTo(t reflect.Type) reflect.Value {
312 // TODO: check that p.v.Type().Elem() == t?
313 return p.v
314}
315
316func atomicLoadUnmarshalInfo(p **unmarshalInfo) *unmarshalInfo {
317 atomicLock.Lock()
318 defer atomicLock.Unlock()
319 return *p
320}
321func atomicStoreUnmarshalInfo(p **unmarshalInfo, v *unmarshalInfo) {
322 atomicLock.Lock()
323 defer atomicLock.Unlock()
324 *p = v
325}
326func atomicLoadMarshalInfo(p **marshalInfo) *marshalInfo {
327 atomicLock.Lock()
328 defer atomicLock.Unlock()
329 return *p
330}
331func atomicStoreMarshalInfo(p **marshalInfo, v *marshalInfo) {
332 atomicLock.Lock()
333 defer atomicLock.Unlock()
334 *p = v
335}
336func atomicLoadMergeInfo(p **mergeInfo) *mergeInfo {
337 atomicLock.Lock()
338 defer atomicLock.Unlock()
339 return *p
340}
341func atomicStoreMergeInfo(p **mergeInfo, v *mergeInfo) {
342 atomicLock.Lock()
343 defer atomicLock.Unlock()
344 *p = v
345}
346func atomicLoadDiscardInfo(p **discardInfo) *discardInfo {
347 atomicLock.Lock()
348 defer atomicLock.Unlock()
349 return *p
350}
351func atomicStoreDiscardInfo(p **discardInfo, v *discardInfo) {
352 atomicLock.Lock()
353 defer atomicLock.Unlock()
354 *p = v
355}
356
357var atomicLock sync.Mutex