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 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, deref bool) pointer { 83 v := reflect.ValueOf(*i) 84 u := reflect.New(v.Type()) 85 u.Elem().Set(v) 86 if deref { 87 u = u.Elem() 88 } 89 return pointer{v: u} 90} 91 92// valToPointer converts v to a pointer. v must be of pointer type. 93func 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. 99func (p pointer) offset(f field) pointer { 100 return pointer{v: p.v.Elem().FieldByIndex(f).Addr()} 101} 102 103func (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. 110func 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 120func (p pointer) toInt64() *int64 { 121 return p.v.Interface().(*int64) 122} 123func (p pointer) toInt64Ptr() **int64 { 124 return p.v.Interface().(**int64) 125} 126func (p pointer) toInt64Slice() *[]int64 { 127 return p.v.Interface().(*[]int64) 128} 129 130var int32ptr = reflect.TypeOf((*int32)(nil)) 131 132func (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*/ 146func (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} 154func (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. 164func (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. 182func (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} 197func (p pointer) appendInt32Slice(v int32) { 198 grow(p.v.Elem()).SetInt(int64(v)) 199} 200 201func (p pointer) toUint64() *uint64 { 202 return p.v.Interface().(*uint64) 203} 204func (p pointer) toUint64Ptr() **uint64 { 205 return p.v.Interface().(**uint64) 206} 207func (p pointer) toUint64Slice() *[]uint64 { 208 return p.v.Interface().(*[]uint64) 209} 210func (p pointer) toUint32() *uint32 { 211 return p.v.Interface().(*uint32) 212} 213func (p pointer) toUint32Ptr() **uint32 { 214 return p.v.Interface().(**uint32) 215} 216func (p pointer) toUint32Slice() *[]uint32 { 217 return p.v.Interface().(*[]uint32) 218} 219func (p pointer) toBool() *bool { 220 return p.v.Interface().(*bool) 221} 222func (p pointer) toBoolPtr() **bool { 223 return p.v.Interface().(**bool) 224} 225func (p pointer) toBoolSlice() *[]bool { 226 return p.v.Interface().(*[]bool) 227} 228func (p pointer) toFloat64() *float64 { 229 return p.v.Interface().(*float64) 230} 231func (p pointer) toFloat64Ptr() **float64 { 232 return p.v.Interface().(**float64) 233} 234func (p pointer) toFloat64Slice() *[]float64 { 235 return p.v.Interface().(*[]float64) 236} 237func (p pointer) toFloat32() *float32 { 238 return p.v.Interface().(*float32) 239} 240func (p pointer) toFloat32Ptr() **float32 { 241 return p.v.Interface().(**float32) 242} 243func (p pointer) toFloat32Slice() *[]float32 { 244 return p.v.Interface().(*[]float32) 245} 246func (p pointer) toString() *string { 247 return p.v.Interface().(*string) 248} 249func (p pointer) toStringPtr() **string { 250 return p.v.Interface().(**string) 251} 252func (p pointer) toStringSlice() *[]string { 253 return p.v.Interface().(*[]string) 254} 255func (p pointer) toBytes() *[]byte { 256 return p.v.Interface().(*[]byte) 257} 258func (p pointer) toBytesSlice() *[][]byte { 259 return p.v.Interface().(*[][]byte) 260} 261func (p pointer) toExtensions() *XXX_InternalExtensions { 262 return p.v.Interface().(*XXX_InternalExtensions) 263} 264func (p pointer) toOldExtensions() *map[int32]Extension { 265 return p.v.Interface().(*map[int32]Extension) 266} 267func (p pointer) getPointer() pointer { 268 return pointer{v: p.v.Elem()} 269} 270func (p pointer) setPointer(q pointer) { 271 p.v.Elem().Set(q.v) 272} 273func (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. 279func (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. 293func (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. 307func (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 314func (p pointer) asPointerTo(t reflect.Type) reflect.Value { 315 // TODO: check that p.v.Type().Elem() == t? 316 return p.v 317} 318 319func atomicLoadUnmarshalInfo(p **unmarshalInfo) *unmarshalInfo { 320 atomicLock.Lock() 321 defer atomicLock.Unlock() 322 return *p 323} 324func atomicStoreUnmarshalInfo(p **unmarshalInfo, v *unmarshalInfo) { 325 atomicLock.Lock() 326 defer atomicLock.Unlock() 327 *p = v 328} 329func atomicLoadMarshalInfo(p **marshalInfo) *marshalInfo { 330 atomicLock.Lock() 331 defer atomicLock.Unlock() 332 return *p 333} 334func atomicStoreMarshalInfo(p **marshalInfo, v *marshalInfo) { 335 atomicLock.Lock() 336 defer atomicLock.Unlock() 337 *p = v 338} 339func atomicLoadMergeInfo(p **mergeInfo) *mergeInfo { 340 atomicLock.Lock() 341 defer atomicLock.Unlock() 342 return *p 343} 344func atomicStoreMergeInfo(p **mergeInfo, v *mergeInfo) { 345 atomicLock.Lock() 346 defer atomicLock.Unlock() 347 *p = v 348} 349func atomicLoadDiscardInfo(p **discardInfo) *discardInfo { 350 atomicLock.Lock() 351 defer atomicLock.Unlock() 352 return *p 353} 354func atomicStoreDiscardInfo(p **discardInfo, v *discardInfo) { 355 atomicLock.Lock() 356 defer atomicLock.Unlock() 357 *p = v 358} 359 360var atomicLock sync.Mutex 361