// Go support for Protocol Buffers - Google's data interchange format // // Copyright 2012 The Go Authors. All rights reserved. // https://github.com/golang/protobuf // // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are // met: // // * Redistributions of source code must retain the above copyright // notice, this list of conditions and the following disclaimer. // * Redistributions in binary form must reproduce the above // copyright notice, this list of conditions and the following disclaimer // in the documentation and/or other materials provided with the // distribution. // * Neither the name of Google Inc. nor the names of its // contributors may be used to endorse or promote products derived from // this software without specific prior written permission. // // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. // +build !purego,!appengine,!js // This file contains the implementation of the proto field accesses using package unsafe. package proto import ( "reflect" "sync/atomic" "unsafe" ) const unsafeAllowed = true // A field identifies a field in a struct, accessible from a pointer. // In this implementation, a field is identified by its byte offset from the start of the struct. type field uintptr // toField returns a field equivalent to the given reflect field. func toField(f *reflect.StructField) field { return field(f.Offset) } // invalidField is an invalid field identifier. const invalidField = ^field(0) // zeroField is a noop when calling pointer.offset. const zeroField = field(0) // IsValid reports whether the field identifier is valid. func (f field) IsValid() bool { return f != invalidField } // The pointer type below is for the new table-driven encoder/decoder. // The implementation here uses unsafe.Pointer to create a generic pointer. // In pointer_reflect.go we use reflect instead of unsafe to implement // the same (but slower) interface. type pointer struct { p unsafe.Pointer } // size of pointer var ptrSize = unsafe.Sizeof(uintptr(0)) // toPointer converts an interface of pointer type to a pointer // that points to the same target. func toPointer(i *Message) pointer { // Super-tricky - read pointer out of data word of interface value. // Saves ~25ns over the equivalent: // return valToPointer(reflect.ValueOf(*i)) return pointer{p: (*[2]unsafe.Pointer)(unsafe.Pointer(i))[1]} } // toAddrPointer converts an interface to a pointer that points to // the interface data. func toAddrPointer(i *interface{}, isptr bool) pointer { // Super-tricky - read or get the address of data word of interface value. if isptr { // The interface is of pointer type, thus it is a direct interface. // The data word is the pointer data itself. We take its address. return pointer{p: unsafe.Pointer(uintptr(unsafe.Pointer(i)) + ptrSize)} } // The interface is not of pointer type. The data word is the pointer // to the data. return pointer{p: (*[2]unsafe.Pointer)(unsafe.Pointer(i))[1]} } // valToPointer converts v to a pointer. v must be of pointer type. func valToPointer(v reflect.Value) pointer { return pointer{p: unsafe.Pointer(v.Pointer())} } // offset converts from a pointer to a structure to a pointer to // one of its fields. func (p pointer) offset(f field) pointer { // For safety, we should panic if !f.IsValid, however calling panic causes // this to no longer be inlineable, which is a serious performance cost. /* if !f.IsValid() { panic("invalid field") } */ return pointer{p: unsafe.Pointer(uintptr(p.p) + uintptr(f))} } func (p pointer) isNil() bool { return p.p == nil } func (p pointer) toInt64() *int64 { return (*int64)(p.p) } func (p pointer) toInt64Ptr() **int64 { return (**int64)(p.p) } func (p pointer) toInt64Slice() *[]int64 { return (*[]int64)(p.p) } func (p pointer) toInt32() *int32 { return (*int32)(p.p) } // See pointer_reflect.go for why toInt32Ptr/Slice doesn't exist. /* func (p pointer) toInt32Ptr() **int32 { return (**int32)(p.p) } func (p pointer) toInt32Slice() *[]int32 { return (*[]int32)(p.p) } */ func (p pointer) getInt32Ptr() *int32 { return *(**int32)(p.p) } func (p pointer) setInt32Ptr(v int32) { *(**int32)(p.p) = &v } // getInt32Slice loads a []int32 from p. // The value returned is aliased with the original slice. // This behavior differs from the implementation in pointer_reflect.go. func (p pointer) getInt32Slice() []int32 { return *(*[]int32)(p.p) } // setInt32Slice stores a []int32 to p. // The value set is aliased with the input slice. // This behavior differs from the implementation in pointer_reflect.go. func (p pointer) setInt32Slice(v []int32) { *(*[]int32)(p.p) = v } // TODO: Can we get rid of appendInt32Slice and use setInt32Slice instead? func (p pointer) appendInt32Slice(v int32) { s := (*[]int32)(p.p) *s = append(*s, v) } func (p pointer) toUint64() *uint64 { return (*uint64)(p.p) } func (p pointer) toUint64Ptr() **uint64 { return (**uint64)(p.p) } func (p pointer) toUint64Slice() *[]uint64 { return (*[]uint64)(p.p) } func (p pointer) toUint32() *uint32 { return (*uint32)(p.p) } func (p pointer) toUint32Ptr() **uint32 { return (**uint32)(p.p) } func (p pointer) toUint32Slice() *[]uint32 { return (*[]uint32)(p.p) } func (p pointer) toBool() *bool { return (*bool)(p.p) } func (p pointer) toBoolPtr() **bool { return (**bool)(p.p) } func (p pointer) toBoolSlice() *[]bool { return (*[]bool)(p.p) } func (p pointer) toFloat64() *float64 { return (*float64)(p.p) } func (p pointer) toFloat64Ptr() **float64 { return (**float64)(p.p) } func (p pointer) toFloat64Slice() *[]float64 { return (*[]float64)(p.p) } func (p pointer) toFloat32() *float32 { return (*float32)(p.p) } func (p pointer) toFloat32Ptr() **float32 { return (**float32)(p.p) } func (p pointer) toFloat32Slice() *[]float32 { return (*[]float32)(p.p) } func (p pointer) toString() *string { return (*string)(p.p) } func (p pointer) toStringPtr() **string { return (**string)(p.p) } func (p pointer) toStringSlice() *[]string { return (*[]string)(p.p) } func (p pointer) toBytes() *[]byte { return (*[]byte)(p.p) } func (p pointer) toBytesSlice() *[][]byte { return (*[][]byte)(p.p) } func (p pointer) toExtensions() *XXX_InternalExtensions { return (*XXX_InternalExtensions)(p.p) } func (p pointer) toOldExtensions() *map[int32]Extension { return (*map[int32]Extension)(p.p) } // getPointerSlice 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) getPointerSlice() []pointer { // Super-tricky - p should point to a []*T where T is a // message type. We load it as []pointer. return *(*[]pointer)(p.p) } // setPointerSlice stores []pointer into p as a []*T. // The value set is aliased with the input slice. // This behavior differs from the implementation in pointer_reflect.go. func (p pointer) setPointerSlice(v []pointer) { // Super-tricky - p should point to a []*T where T is a // message type. We store it as []pointer. *(*[]pointer)(p.p) = v } // getPointer loads the pointer at p and returns it. func (p pointer) getPointer() pointer { return pointer{p: *(*unsafe.Pointer)(p.p)} } // setPointer stores the pointer q at p. func (p pointer) setPointer(q pointer) { *(*unsafe.Pointer)(p.p) = q.p } // append q to the slice pointed to by p. func (p pointer) appendPointer(q pointer) { s := (*[]unsafe.Pointer)(p.p) *s = append(*s, q.p) } // getInterfacePointer returns a pointer that points to the // interface data of the interface pointed by p. func (p pointer) getInterfacePointer() pointer { // Super-tricky - read pointer out of data word of interface value. return pointer{p: (*(*[2]unsafe.Pointer)(p.p))[1]} } // asPointerTo returns a reflect.Value that is a pointer to an // object of type t stored at p. func (p pointer) asPointerTo(t reflect.Type) reflect.Value { return reflect.NewAt(t, p.p) } func atomicLoadUnmarshalInfo(p **unmarshalInfo) *unmarshalInfo { return (*unmarshalInfo)(atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(p)))) } func atomicStoreUnmarshalInfo(p **unmarshalInfo, v *unmarshalInfo) { atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(p)), unsafe.Pointer(v)) } func atomicLoadMarshalInfo(p **marshalInfo) *marshalInfo { return (*marshalInfo)(atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(p)))) } func atomicStoreMarshalInfo(p **marshalInfo, v *marshalInfo) { atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(p)), unsafe.Pointer(v)) } func atomicLoadMergeInfo(p **mergeInfo) *mergeInfo { return (*mergeInfo)(atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(p)))) } func atomicStoreMergeInfo(p **mergeInfo, v *mergeInfo) { atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(p)), unsafe.Pointer(v)) } func atomicLoadDiscardInfo(p **discardInfo) *discardInfo { return (*discardInfo)(atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(p)))) } func atomicStoreDiscardInfo(p **discardInfo, v *discardInfo) { atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(p)), unsafe.Pointer(v)) }