diff options
Diffstat (limited to 'vendor/google.golang.org/protobuf/reflect/protoreflect/value_unsafe.go')
-rw-r--r-- | vendor/google.golang.org/protobuf/reflect/protoreflect/value_unsafe.go | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/vendor/google.golang.org/protobuf/reflect/protoreflect/value_unsafe.go b/vendor/google.golang.org/protobuf/reflect/protoreflect/value_unsafe.go new file mode 100644 index 000000000..c45debdca --- /dev/null +++ b/vendor/google.golang.org/protobuf/reflect/protoreflect/value_unsafe.go @@ -0,0 +1,98 @@ +// 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 protoreflect + +import ( + "unsafe" + + "google.golang.org/protobuf/internal/pragma" +) + +type ( + stringHeader struct { + Data unsafe.Pointer + Len int + } + sliceHeader struct { + Data unsafe.Pointer + Len int + Cap int + } + ifaceHeader struct { + Type unsafe.Pointer + Data unsafe.Pointer + } +) + +var ( + nilType = typeOf(nil) + boolType = typeOf(*new(bool)) + int32Type = typeOf(*new(int32)) + int64Type = typeOf(*new(int64)) + uint32Type = typeOf(*new(uint32)) + uint64Type = typeOf(*new(uint64)) + float32Type = typeOf(*new(float32)) + float64Type = typeOf(*new(float64)) + stringType = typeOf(*new(string)) + bytesType = typeOf(*new([]byte)) + enumType = typeOf(*new(EnumNumber)) +) + +// typeOf returns a pointer to the Go type information. +// The pointer is comparable and equal if and only if the types are identical. +func typeOf(t interface{}) unsafe.Pointer { + return (*ifaceHeader)(unsafe.Pointer(&t)).Type +} + +// value is a union where only one type can be represented at a time. +// The struct is 24B large on 64-bit systems and requires the minimum storage +// necessary to represent each possible type. +// +// The Go GC needs to be able to scan variables containing pointers. +// As such, pointers and non-pointers cannot be intermixed. +type value struct { + pragma.DoNotCompare // 0B + + // typ stores the type of the value as a pointer to the Go type. + typ unsafe.Pointer // 8B + + // ptr stores the data pointer for a String, Bytes, or interface value. + ptr unsafe.Pointer // 8B + + // num stores a Bool, Int32, Int64, Uint32, Uint64, Float32, Float64, or + // Enum value as a raw uint64. + // + // It is also used to store the length of a String or Bytes value; + // the capacity is ignored. + num uint64 // 8B +} + +func valueOfString(v string) Value { + p := (*stringHeader)(unsafe.Pointer(&v)) + return Value{typ: stringType, ptr: p.Data, num: uint64(len(v))} +} +func valueOfBytes(v []byte) Value { + p := (*sliceHeader)(unsafe.Pointer(&v)) + return Value{typ: bytesType, ptr: p.Data, num: uint64(len(v))} +} +func valueOfIface(v interface{}) Value { + p := (*ifaceHeader)(unsafe.Pointer(&v)) + return Value{typ: p.Type, ptr: p.Data} +} + +func (v Value) getString() (x string) { + *(*stringHeader)(unsafe.Pointer(&x)) = stringHeader{Data: v.ptr, Len: int(v.num)} + return x +} +func (v Value) getBytes() (x []byte) { + *(*sliceHeader)(unsafe.Pointer(&x)) = sliceHeader{Data: v.ptr, Len: int(v.num), Cap: int(v.num)} + return x +} +func (v Value) getIface() (x interface{}) { + *(*ifaceHeader)(unsafe.Pointer(&x)) = ifaceHeader{Type: v.typ, Data: v.ptr} + return x +} |