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15c0b25d AP |
1 | // 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 | ||
38 | package proto | |
39 | ||
40 | import ( | |
41 | "reflect" | |
42 | "sync" | |
43 | ) | |
44 | ||
45 | const 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. | |
50 | type field []int | |
51 | ||
52 | // toField returns a field equivalent to the given reflect field. | |
53 | func toField(f *reflect.StructField) field { | |
54 | return f.Index | |
55 | } | |
56 | ||
57 | // invalidField is an invalid field identifier. | |
58 | var invalidField = field(nil) | |
59 | ||
60 | // zeroField is a noop when calling pointer.offset. | |
61 | var zeroField = field([]int{}) | |
62 | ||
63 | // IsValid reports whether the field identifier is valid. | |
64 | func (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. | |
70 | type 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. | |
76 | func 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. | |
107c1cdb | 82 | func toAddrPointer(i *interface{}, isptr, deref bool) pointer { |
15c0b25d AP |
83 | v := reflect.ValueOf(*i) |
84 | u := reflect.New(v.Type()) | |
85 | u.Elem().Set(v) | |
107c1cdb ND |
86 | if deref { |
87 | u = u.Elem() | |
88 | } | |
15c0b25d AP |
89 | return pointer{v: u} |
90 | } | |
91 | ||
92 | // valToPointer converts v to a pointer. v must be of pointer type. | |
93 | func valToPointer(v reflect.Value) pointer { | |
94 | return pointer{v: v} | |
95 | } | |
96 | ||
97 | // offset converts from a pointer to a structure to a pointer to | |
98 | // one of its fields. | |
99 | func (p pointer) offset(f field) pointer { | |
100 | return pointer{v: p.v.Elem().FieldByIndex(f).Addr()} | |
101 | } | |
102 | ||
103 | func (p pointer) isNil() bool { | |
104 | return p.v.IsNil() | |
105 | } | |
106 | ||
107 | // grow updates the slice s in place to make it one element longer. | |
108 | // s must be addressable. | |
109 | // Returns the (addressable) new element. | |
110 | func grow(s reflect.Value) reflect.Value { | |
111 | n, m := s.Len(), s.Cap() | |
112 | if n < m { | |
113 | s.SetLen(n + 1) | |
114 | } else { | |
115 | s.Set(reflect.Append(s, reflect.Zero(s.Type().Elem()))) | |
116 | } | |
117 | return s.Index(n) | |
118 | } | |
119 | ||
120 | func (p pointer) toInt64() *int64 { | |
121 | return p.v.Interface().(*int64) | |
122 | } | |
123 | func (p pointer) toInt64Ptr() **int64 { | |
124 | return p.v.Interface().(**int64) | |
125 | } | |
126 | func (p pointer) toInt64Slice() *[]int64 { | |
127 | return p.v.Interface().(*[]int64) | |
128 | } | |
129 | ||
130 | var int32ptr = reflect.TypeOf((*int32)(nil)) | |
131 | ||
132 | func (p pointer) toInt32() *int32 { | |
133 | return p.v.Convert(int32ptr).Interface().(*int32) | |
134 | } | |
135 | ||
136 | // The toInt32Ptr/Slice methods don't work because of enums. | |
137 | // Instead, we must use set/get methods for the int32ptr/slice case. | |
138 | /* | |
139 | func (p pointer) toInt32Ptr() **int32 { | |
140 | return p.v.Interface().(**int32) | |
141 | } | |
142 | func (p pointer) toInt32Slice() *[]int32 { | |
143 | return p.v.Interface().(*[]int32) | |
144 | } | |
145 | */ | |
146 | func (p pointer) getInt32Ptr() *int32 { | |
147 | if p.v.Type().Elem().Elem() == reflect.TypeOf(int32(0)) { | |
148 | // raw int32 type | |
149 | return p.v.Elem().Interface().(*int32) | |
150 | } | |
151 | // an enum | |
152 | return p.v.Elem().Convert(int32PtrType).Interface().(*int32) | |
153 | } | |
154 | func (p pointer) setInt32Ptr(v int32) { | |
155 | // Allocate value in a *int32. Possibly convert that to a *enum. | |
156 | // Then assign it to a **int32 or **enum. | |
157 | // Note: we can convert *int32 to *enum, but we can't convert | |
158 | // **int32 to **enum! | |
159 | p.v.Elem().Set(reflect.ValueOf(&v).Convert(p.v.Type().Elem())) | |
160 | } | |
161 | ||
162 | // getInt32Slice copies []int32 from p as a new slice. | |
163 | // This behavior differs from the implementation in pointer_unsafe.go. | |
164 | func (p pointer) getInt32Slice() []int32 { | |
165 | if p.v.Type().Elem().Elem() == reflect.TypeOf(int32(0)) { | |
166 | // raw int32 type | |
167 | return p.v.Elem().Interface().([]int32) | |
168 | } | |
169 | // an enum | |
170 | // Allocate a []int32, then assign []enum's values into it. | |
171 | // Note: we can't convert []enum to []int32. | |
172 | slice := p.v.Elem() | |
173 | s := make([]int32, slice.Len()) | |
174 | for i := 0; i < slice.Len(); i++ { | |
175 | s[i] = int32(slice.Index(i).Int()) | |
176 | } | |
177 | return s | |
178 | } | |
179 | ||
180 | // setInt32Slice copies []int32 into p as a new slice. | |
181 | // This behavior differs from the implementation in pointer_unsafe.go. | |
182 | func (p pointer) setInt32Slice(v []int32) { | |
183 | if p.v.Type().Elem().Elem() == reflect.TypeOf(int32(0)) { | |
184 | // raw int32 type | |
185 | p.v.Elem().Set(reflect.ValueOf(v)) | |
186 | return | |
187 | } | |
188 | // an enum | |
189 | // Allocate a []enum, then assign []int32's values into it. | |
190 | // Note: we can't convert []enum to []int32. | |
191 | slice := reflect.MakeSlice(p.v.Type().Elem(), len(v), cap(v)) | |
192 | for i, x := range v { | |
193 | slice.Index(i).SetInt(int64(x)) | |
194 | } | |
195 | p.v.Elem().Set(slice) | |
196 | } | |
197 | func (p pointer) appendInt32Slice(v int32) { | |
198 | grow(p.v.Elem()).SetInt(int64(v)) | |
199 | } | |
200 | ||
201 | func (p pointer) toUint64() *uint64 { | |
202 | return p.v.Interface().(*uint64) | |
203 | } | |
204 | func (p pointer) toUint64Ptr() **uint64 { | |
205 | return p.v.Interface().(**uint64) | |
206 | } | |
207 | func (p pointer) toUint64Slice() *[]uint64 { | |
208 | return p.v.Interface().(*[]uint64) | |
209 | } | |
210 | func (p pointer) toUint32() *uint32 { | |
211 | return p.v.Interface().(*uint32) | |
212 | } | |
213 | func (p pointer) toUint32Ptr() **uint32 { | |
214 | return p.v.Interface().(**uint32) | |
215 | } | |
216 | func (p pointer) toUint32Slice() *[]uint32 { | |
217 | return p.v.Interface().(*[]uint32) | |
218 | } | |
219 | func (p pointer) toBool() *bool { | |
220 | return p.v.Interface().(*bool) | |
221 | } | |
222 | func (p pointer) toBoolPtr() **bool { | |
223 | return p.v.Interface().(**bool) | |
224 | } | |
225 | func (p pointer) toBoolSlice() *[]bool { | |
226 | return p.v.Interface().(*[]bool) | |
227 | } | |
228 | func (p pointer) toFloat64() *float64 { | |
229 | return p.v.Interface().(*float64) | |
230 | } | |
231 | func (p pointer) toFloat64Ptr() **float64 { | |
232 | return p.v.Interface().(**float64) | |
233 | } | |
234 | func (p pointer) toFloat64Slice() *[]float64 { | |
235 | return p.v.Interface().(*[]float64) | |
236 | } | |
237 | func (p pointer) toFloat32() *float32 { | |
238 | return p.v.Interface().(*float32) | |
239 | } | |
240 | func (p pointer) toFloat32Ptr() **float32 { | |
241 | return p.v.Interface().(**float32) | |
242 | } | |
243 | func (p pointer) toFloat32Slice() *[]float32 { | |
244 | return p.v.Interface().(*[]float32) | |
245 | } | |
246 | func (p pointer) toString() *string { | |
247 | return p.v.Interface().(*string) | |
248 | } | |
249 | func (p pointer) toStringPtr() **string { | |
250 | return p.v.Interface().(**string) | |
251 | } | |
252 | func (p pointer) toStringSlice() *[]string { | |
253 | return p.v.Interface().(*[]string) | |
254 | } | |
255 | func (p pointer) toBytes() *[]byte { | |
256 | return p.v.Interface().(*[]byte) | |
257 | } | |
258 | func (p pointer) toBytesSlice() *[][]byte { | |
259 | return p.v.Interface().(*[][]byte) | |
260 | } | |
261 | func (p pointer) toExtensions() *XXX_InternalExtensions { | |
262 | return p.v.Interface().(*XXX_InternalExtensions) | |
263 | } | |
264 | func (p pointer) toOldExtensions() *map[int32]Extension { | |
265 | return p.v.Interface().(*map[int32]Extension) | |
266 | } | |
267 | func (p pointer) getPointer() pointer { | |
268 | return pointer{v: p.v.Elem()} | |
269 | } | |
270 | func (p pointer) setPointer(q pointer) { | |
271 | p.v.Elem().Set(q.v) | |
272 | } | |
273 | func (p pointer) appendPointer(q pointer) { | |
274 | grow(p.v.Elem()).Set(q.v) | |
275 | } | |
276 | ||
277 | // getPointerSlice copies []*T from p as a new []pointer. | |
278 | // This behavior differs from the implementation in pointer_unsafe.go. | |
279 | func (p pointer) getPointerSlice() []pointer { | |
280 | if p.v.IsNil() { | |
281 | return nil | |
282 | } | |
283 | n := p.v.Elem().Len() | |
284 | s := make([]pointer, n) | |
285 | for i := 0; i < n; i++ { | |
286 | s[i] = pointer{v: p.v.Elem().Index(i)} | |
287 | } | |
288 | return s | |
289 | } | |
290 | ||
291 | // setPointerSlice copies []pointer into p as a new []*T. | |
292 | // This behavior differs from the implementation in pointer_unsafe.go. | |
293 | func (p pointer) setPointerSlice(v []pointer) { | |
294 | if v == nil { | |
295 | p.v.Elem().Set(reflect.New(p.v.Elem().Type()).Elem()) | |
296 | return | |
297 | } | |
298 | s := reflect.MakeSlice(p.v.Elem().Type(), 0, len(v)) | |
299 | for _, p := range v { | |
300 | s = reflect.Append(s, p.v) | |
301 | } | |
302 | p.v.Elem().Set(s) | |
303 | } | |
304 | ||
305 | // getInterfacePointer returns a pointer that points to the | |
306 | // interface data of the interface pointed by p. | |
307 | func (p pointer) getInterfacePointer() pointer { | |
308 | if p.v.Elem().IsNil() { | |
309 | return pointer{v: p.v.Elem()} | |
310 | } | |
311 | return pointer{v: p.v.Elem().Elem().Elem().Field(0).Addr()} // *interface -> interface -> *struct -> struct | |
312 | } | |
313 | ||
314 | func (p pointer) asPointerTo(t reflect.Type) reflect.Value { | |
315 | // TODO: check that p.v.Type().Elem() == t? | |
316 | return p.v | |
317 | } | |
318 | ||
319 | func atomicLoadUnmarshalInfo(p **unmarshalInfo) *unmarshalInfo { | |
320 | atomicLock.Lock() | |
321 | defer atomicLock.Unlock() | |
322 | return *p | |
323 | } | |
324 | func atomicStoreUnmarshalInfo(p **unmarshalInfo, v *unmarshalInfo) { | |
325 | atomicLock.Lock() | |
326 | defer atomicLock.Unlock() | |
327 | *p = v | |
328 | } | |
329 | func atomicLoadMarshalInfo(p **marshalInfo) *marshalInfo { | |
330 | atomicLock.Lock() | |
331 | defer atomicLock.Unlock() | |
332 | return *p | |
333 | } | |
334 | func atomicStoreMarshalInfo(p **marshalInfo, v *marshalInfo) { | |
335 | atomicLock.Lock() | |
336 | defer atomicLock.Unlock() | |
337 | *p = v | |
338 | } | |
339 | func atomicLoadMergeInfo(p **mergeInfo) *mergeInfo { | |
340 | atomicLock.Lock() | |
341 | defer atomicLock.Unlock() | |
342 | return *p | |
343 | } | |
344 | func atomicStoreMergeInfo(p **mergeInfo, v *mergeInfo) { | |
345 | atomicLock.Lock() | |
346 | defer atomicLock.Unlock() | |
347 | *p = v | |
348 | } | |
349 | func atomicLoadDiscardInfo(p **discardInfo) *discardInfo { | |
350 | atomicLock.Lock() | |
351 | defer atomicLock.Unlock() | |
352 | return *p | |
353 | } | |
354 | func atomicStoreDiscardInfo(p **discardInfo, v *discardInfo) { | |
355 | atomicLock.Lock() | |
356 | defer atomicLock.Unlock() | |
357 | *p = v | |
358 | } | |
359 | ||
360 | var atomicLock sync.Mutex |