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Commit 9650726e authored by Marcel van Lohuizen's avatar Marcel van Lohuizen
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internal/reflectlite: lite version of reflect package 

to be used by errors package for checking assignability
and setting error values in As.

Updates #29934.

Change-Id: I8c1d02a2c6efa0919d54b286cfe8b4edc26da059
Reviewed-on: https://go-review.googlesource.com/c/161759
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: default avatarRuss Cox <rsc@golang.org>
parent b9596aea
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src/go/build/deps_test.go
View file @ 9650726e
......@@ -46,6 +46,7 @@ var pkgDeps = map[string][]string{
"unsafe": {},
"internal/cpu": {},
"internal/bytealg": {"unsafe", "internal/cpu"},
"internal/reflectlite": {"runtime", "unsafe"},
"L0": {
"errors",
......@@ -57,6 +58,7 @@ var pkgDeps = map[string][]string{
"unsafe",
"internal/cpu",
"internal/bytealg",
"internal/reflectlite",
},
// L1 adds simple functions and strings processing,
......
src/internal/reflectlite/all_test.go 0 → 100644
View file @ 9650726e
// Copyright 2009 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.
package reflectlite_test
import (
"encoding/base64"
"fmt"
. "internal/reflectlite"
"math"
"reflect"
"runtime"
"testing"
"unsafe"
)
func ToValue(v Value) reflect.Value {
return reflect.ValueOf(ToInterface(v))
}
func TypeString(t Type) string {
return fmt.Sprintf("%T", ToInterface(Zero(t)))
}
type integer int
type T struct {
a int
b float64
c string
d *int
}
type pair struct {
i interface{}
s string
}
func assert(t *testing.T, s, want string) {
t.Helper()
if s != want {
t.Errorf("have %#q want %#q", s, want)
}
}
var typeTests = []pair{
{struct{ x int }{}, "int"},
{struct{ x int8 }{}, "int8"},
{struct{ x int16 }{}, "int16"},
{struct{ x int32 }{}, "int32"},
{struct{ x int64 }{}, "int64"},
{struct{ x uint }{}, "uint"},
{struct{ x uint8 }{}, "uint8"},
{struct{ x uint16 }{}, "uint16"},
{struct{ x uint32 }{}, "uint32"},
{struct{ x uint64 }{}, "uint64"},
{struct{ x float32 }{}, "float32"},
{struct{ x float64 }{}, "float64"},
{struct{ x int8 }{}, "int8"},
{struct{ x (**int8) }{}, "**int8"},
{struct{ x (**integer) }{}, "**reflectlite_test.integer"},
{struct{ x ([32]int32) }{}, "[32]int32"},
{struct{ x ([]int8) }{}, "[]int8"},
{struct{ x (map[string]int32) }{}, "map[string]int32"},
{struct{ x (chan<- string) }{}, "chan<- string"},
{struct {
x struct {
c chan *int32
d float32
}
}{},
"struct { c chan *int32; d float32 }",
},
{struct{ x (func(a int8, b int32)) }{}, "func(int8, int32)"},
{struct {
x struct {
c func(chan *integer, *int8)
}
}{},
"struct { c func(chan *reflectlite_test.integer, *int8) }",
},
{struct {
x struct {
a int8
b int32
}
}{},
"struct { a int8; b int32 }",
},
{struct {
x struct {
a int8
b int8
c int32
}
}{},
"struct { a int8; b int8; c int32 }",
},
{struct {
x struct {
a int8
b int8
c int8
d int32
}
}{},
"struct { a int8; b int8; c int8; d int32 }",
},
{struct {
x struct {
a int8
b int8
c int8
d int8
e int32
}
}{},
"struct { a int8; b int8; c int8; d int8; e int32 }",
},
{struct {
x struct {
a int8
b int8
c int8
d int8
e int8
f int32
}
}{},
"struct { a int8; b int8; c int8; d int8; e int8; f int32 }",
},
{struct {
x struct {
a int8 `reflect:"hi there"`
}
}{},
`struct { a int8 "reflect:\"hi there\"" }`,
},
{struct {
x struct {
a int8 `reflect:"hi \x00there\t\n\"\\"`
}
}{},
`struct { a int8 "reflect:\"hi \\x00there\\t\\n\\\"\\\\\"" }`,
},
{struct {
x struct {
f func(args ...int)
}
}{},
"struct { f func(...int) }",
},
// {struct {
// x (interface {
// a(func(func(int) int) func(func(int)) int)
// b()
// })
// }{},
// "interface { reflectlite_test.a(func(func(int) int) func(func(int)) int); reflectlite_test.b() }",
// },
{struct {
x struct {
int32
int64
}
}{},
"struct { int32; int64 }",
},
}
var valueTests = []pair{
{new(int), "132"},
{new(int8), "8"},
{new(int16), "16"},
{new(int32), "32"},
{new(int64), "64"},
{new(uint), "132"},
{new(uint8), "8"},
{new(uint16), "16"},
{new(uint32), "32"},
{new(uint64), "64"},
{new(float32), "256.25"},
{new(float64), "512.125"},
{new(complex64), "532.125+10i"},
{new(complex128), "564.25+1i"},
{new(string), "stringy cheese"},
{new(bool), "true"},
{new(*int8), "*int8(0)"},
{new(**int8), "**int8(0)"},
{new([5]int32), "[5]int32{0, 0, 0, 0, 0}"},
{new(**integer), "**reflectlite_test.integer(0)"},
{new(map[string]int32), "map[string]int32{<can't iterate on maps>}"},
{new(chan<- string), "chan<- string"},
{new(func(a int8, b int32)), "func(int8, int32)(arg)"},
{new(struct {
c chan *int32
d float32
}),
"struct { c chan *int32; d float32 }{chan *int32, 0}",
},
{new(struct{ c func(chan *integer, *int8) }),
"struct { c func(chan *reflectlite_test.integer, *int8) }{func(chan *reflectlite_test.integer, *int8)(arg)}",
},
{new(struct {
a int8
b int32
}),
"struct { a int8; b int32 }{0, 0}",
},
{new(struct {
a int8
b int8
c int32
}),
"struct { a int8; b int8; c int32 }{0, 0, 0}",
},
}
func testType(t *testing.T, i int, typ Type, want string) {
s := TypeString(typ)
if s != want {
t.Errorf("#%d: have %#q, want %#q", i, s, want)
}
}
func testReflectType(t *testing.T, i int, typ Type, want string) {
s := TypeString(typ)
if s != want {
t.Errorf("#%d: have %#q, want %#q", i, s, want)
}
}
func TestTypes(t *testing.T) {
for i, tt := range typeTests {
testReflectType(t, i, Field(ValueOf(tt.i), 0).Type(), tt.s)
}
}
func TestSetValue(t *testing.T) {
for i, tt := range valueTests {
v := ValueOf(tt.i).Elem()
switch v.Kind() {
case Int:
v.Set(ValueOf(int(132)))
case Int8:
v.Set(ValueOf(int8(8)))
case Int16:
v.Set(ValueOf(int16(16)))
case Int32:
v.Set(ValueOf(int32(32)))
case Int64:
v.Set(ValueOf(int64(64)))
case Uint:
v.Set(ValueOf(uint(132)))
case Uint8:
v.Set(ValueOf(uint8(8)))
case Uint16:
v.Set(ValueOf(uint16(16)))
case Uint32:
v.Set(ValueOf(uint32(32)))
case Uint64:
v.Set(ValueOf(uint64(64)))
case Float32:
v.Set(ValueOf(float32(256.25)))
case Float64:
v.Set(ValueOf(512.125))
case Complex64:
v.Set(ValueOf(complex64(532.125 + 10i)))
case Complex128:
v.Set(ValueOf(complex128(564.25 + 1i)))
case String:
v.Set(ValueOf("stringy cheese"))
case Bool:
v.Set(ValueOf(true))
}
s := valueToString(v)
if s != tt.s {
t.Errorf("#%d: have %#q, want %#q", i, s, tt.s)
}
}
}
func TestCanSetField(t *testing.T) {
type embed struct{ x, X int }
type Embed struct{ x, X int }
type S1 struct {
embed
x, X int
}
type S2 struct {
*embed
x, X int
}
type S3 struct {
Embed
x, X int
}
type S4 struct {
*Embed
x, X int
}
type testCase struct {
index []int
canSet bool
}
tests := []struct {
val Value
cases []testCase
}{{
val: ValueOf(&S1{}),
cases: []testCase{
{[]int{0}, false},
{[]int{0, 0}, false},
{[]int{0, 1}, true},
{[]int{1}, false},
{[]int{2}, true},
},
}, {
val: ValueOf(&S2{embed: &embed{}}),
cases: []testCase{
{[]int{0}, false},
{[]int{0, 0}, false},
{[]int{0, 1}, true},
{[]int{1}, false},
{[]int{2}, true},
},
}, {
val: ValueOf(&S3{}),
cases: []testCase{
{[]int{0}, true},
{[]int{0, 0}, false},
{[]int{0, 1}, true},
{[]int{1}, false},
{[]int{2}, true},
},
}, {
val: ValueOf(&S4{Embed: &Embed{}}),
cases: []testCase{
{[]int{0}, true},
{[]int{0, 0}, false},
{[]int{0, 1}, true},
{[]int{1}, false},
{[]int{2}, true},
},
}}
for _, tt := range tests {
t.Run(tt.val.Type().Name(), func(t *testing.T) {
for _, tc := range tt.cases {
f := tt.val
for _, i := range tc.index {
if f.Kind() == Ptr {
f = f.Elem()
}
f = Field(f, i)
}
if got := f.CanSet(); got != tc.canSet {
t.Errorf("CanSet() = %v, want %v", got, tc.canSet)
}
}
})
}
}
var _i = 7
var valueToStringTests = []pair{
{123, "123"},
{123.5, "123.5"},
{byte(123), "123"},
{"abc", "abc"},
{T{123, 456.75, "hello", &_i}, "reflectlite_test.T{123, 456.75, hello, *int(&7)}"},
{new(chan *T), "*chan *reflectlite_test.T(&chan *reflectlite_test.T)"},
{[10]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, "[10]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}"},
{&[10]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, "*[10]int(&[10]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10})"},
{[]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, "[]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}"},
{&[]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, "*[]int(&[]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10})"},
}
func TestValueToString(t *testing.T) {
for i, test := range valueToStringTests {
s := valueToString(ValueOf(test.i))
if s != test.s {
t.Errorf("#%d: have %#q, want %#q", i, s, test.s)
}
}
}
func TestPtrSetNil(t *testing.T) {
var i int32 = 1234
ip := &i
vip := ValueOf(&ip)
vip.Elem().Set(Zero(vip.Elem().Type()))
if ip != nil {
t.Errorf("got non-nil (%d), want nil", *ip)
}
}
func TestMapSetNil(t *testing.T) {
m := make(map[string]int)
vm := ValueOf(&m)
vm.Elem().Set(Zero(vm.Elem().Type()))
if m != nil {
t.Errorf("got non-nil (%p), want nil", m)
}
}
func TestAll(t *testing.T) {
testType(t, 1, TypeOf((int8)(0)), "int8")
testType(t, 2, TypeOf((*int8)(nil)).Elem(), "int8")
typ := TypeOf((*struct {
c chan *int32
d float32
})(nil))
testType(t, 3, typ, "*struct { c chan *int32; d float32 }")
etyp := typ.Elem()
testType(t, 4, etyp, "struct { c chan *int32; d float32 }")
}
func TestInterfaceValue(t *testing.T) {
var inter struct {
E interface{}
}
inter.E = 123.456
v1 := ValueOf(&inter)
v2 := Field(v1.Elem(), 0)
// assert(t, TypeString(v2.Type()), "interface {}")
v3 := v2.Elem()
assert(t, TypeString(v3.Type()), "float64")
i3 := ToInterface(v2)
if _, ok := i3.(float64); !ok {
t.Error("v2.Interface() did not return float64, got ", TypeOf(i3))
}
}
func TestFunctionValue(t *testing.T) {
var x interface{} = func() {}
v := ValueOf(x)
if fmt.Sprint(ToInterface(v)) != fmt.Sprint(x) {
t.Fatalf("TestFunction returned wrong pointer")
}
assert(t, TypeString(v.Type()), "func()")
}
var appendTests = []struct {
orig, extra []int
}{
{make([]int, 2, 4), []int{22}},
{make([]int, 2, 4), []int{22, 33, 44}},
}
func sameInts(x, y []int) bool {
if len(x) != len(y) {
return false
}
for i, xx := range x {
if xx != y[i] {
return false
}
}
return true
}
func TestBigUnnamedStruct(t *testing.T) {
b := struct{ a, b, c, d int64 }{1, 2, 3, 4}
v := ValueOf(b)
b1 := ToInterface(v).(struct {
a, b, c, d int64
})
if b1.a != b.a || b1.b != b.b || b1.c != b.c || b1.d != b.d {
t.Errorf("ValueOf(%v).Interface().(*Big) = %v", b, b1)
}
}
type big struct {
a, b, c, d, e int64
}
func TestBigStruct(t *testing.T) {
b := big{1, 2, 3, 4, 5}
v := ValueOf(b)
b1 := ToInterface(v).(big)
if b1.a != b.a || b1.b != b.b || b1.c != b.c || b1.d != b.d || b1.e != b.e {
t.Errorf("ValueOf(%v).Interface().(big) = %v", b, b1)
}
}
type Basic struct {
x int
y float32
}
type NotBasic Basic
type DeepEqualTest struct {
a, b interface{}
eq bool
}
// Simple functions for DeepEqual tests.
var (
fn1 func() // nil.
fn2 func() // nil.
fn3 = func() { fn1() } // Not nil.
)
type self struct{}
type Loop *Loop
type Loopy interface{}
var loop1, loop2 Loop
var loopy1, loopy2 Loopy
func init() {
loop1 = &loop2
loop2 = &loop1
loopy1 = &loopy2
loopy2 = &loopy1
}
var typeOfTests = []DeepEqualTest{
// Equalities
{nil, nil, true},
{1, 1, true},
{int32(1), int32(1), true},
{0.5, 0.5, true},
{float32(0.5), float32(0.5), true},
{"hello", "hello", true},
{make([]int, 10), make([]int, 10), true},
{&[3]int{1, 2, 3}, &[3]int{1, 2, 3}, true},
{Basic{1, 0.5}, Basic{1, 0.5}, true},
{error(nil), error(nil), true},
{map[int]string{1: "one", 2: "two"}, map[int]string{2: "two", 1: "one"}, true},
{fn1, fn2, true},
// Inequalities
{1, 2, false},
{int32(1), int32(2), false},
{0.5, 0.6, false},
{float32(0.5), float32(0.6), false},
{"hello", "hey", false},
{make([]int, 10), make([]int, 11), false},
{&[3]int{1, 2, 3}, &[3]int{1, 2, 4}, false},
{Basic{1, 0.5}, Basic{1, 0.6}, false},
{Basic{1, 0}, Basic{2, 0}, false},
{map[int]string{1: "one", 3: "two"}, map[int]string{2: "two", 1: "one"}, false},
{map[int]string{1: "one", 2: "txo"}, map[int]string{2: "two", 1: "one"}, false},
{map[int]string{1: "one"}, map[int]string{2: "two", 1: "one"}, false},
{map[int]string{2: "two", 1: "one"}, map[int]string{1: "one"}, false},
{nil, 1, false},
{1, nil, false},
{fn1, fn3, false},
{fn3, fn3, false},
{[][]int{{1}}, [][]int{{2}}, false},
{math.NaN(), math.NaN(), false},
{&[1]float64{math.NaN()}, &[1]float64{math.NaN()}, false},
{&[1]float64{math.NaN()}, self{}, true},
{[]float64{math.NaN()}, []float64{math.NaN()}, false},
{[]float64{math.NaN()}, self{}, true},
{map[float64]float64{math.NaN(): 1}, map[float64]float64{1: 2}, false},
{map[float64]float64{math.NaN(): 1}, self{}, true},
// Nil vs empty: not the same.
{[]int{}, []int(nil), false},
{[]int{}, []int{}, true},
{[]int(nil), []int(nil), true},
{map[int]int{}, map[int]int(nil), false},
{map[int]int{}, map[int]int{}, true},
{map[int]int(nil), map[int]int(nil), true},
// Mismatched types
{1, 1.0, false},
{int32(1), int64(1), false},
{0.5, "hello", false},
{[]int{1, 2, 3}, [3]int{1, 2, 3}, false},
{&[3]interface{}{1, 2, 4}, &[3]interface{}{1, 2, "s"}, false},
{Basic{1, 0.5}, NotBasic{1, 0.5}, false},
{map[uint]string{1: "one", 2: "two"}, map[int]string{2: "two", 1: "one"}, false},
// Possible loops.
{&loop1, &loop1, true},
{&loop1, &loop2, true},
{&loopy1, &loopy1, true},
{&loopy1, &loopy2, true},
}
func TestTypeOf(t *testing.T) {
// Special case for nil
if typ := TypeOf(nil); typ != nil {
t.Errorf("expected nil type for nil value; got %v", typ)
}
for _, test := range typeOfTests {
v := ValueOf(test.a)
if !v.IsValid() {
continue
}
typ := TypeOf(test.a)
if typ != v.Type() {
t.Errorf("TypeOf(%v) = %v, but ValueOf(%v).Type() = %v", test.a, typ, test.a, v.Type())
}
}
}
func Nil(a interface{}, t *testing.T) {
n := Field(ValueOf(a), 0)
if !n.IsNil() {
t.Errorf("%v should be nil", a)
}
}
func NotNil(a interface{}, t *testing.T) {
n := Field(ValueOf(a), 0)
if n.IsNil() {
t.Errorf("value of type %v should not be nil", TypeString(ValueOf(a).Type()))
}
}
func TestIsNil(t *testing.T) {
// These implement IsNil.
// Wrap in extra struct to hide interface type.
doNil := []interface{}{
struct{ x *int }{},
struct{ x interface{} }{},
struct{ x map[string]int }{},
struct{ x func() bool }{},
struct{ x chan int }{},
struct{ x []string }{},
struct{ x unsafe.Pointer }{},
}
for _, ts := range doNil {
ty := TField(TypeOf(ts), 0)
v := Zero(ty)
v.IsNil() // panics if not okay to call
}
// Check the implementations
var pi struct {
x *int
}
Nil(pi, t)
pi.x = new(int)
NotNil(pi, t)
var si struct {
x []int
}
Nil(si, t)
si.x = make([]int, 10)
NotNil(si, t)
var ci struct {
x chan int
}
Nil(ci, t)
ci.x = make(chan int)
NotNil(ci, t)
var mi struct {
x map[int]int
}
Nil(mi, t)
mi.x = make(map[int]int)
NotNil(mi, t)
var ii struct {
x interface{}
}
Nil(ii, t)
ii.x = 2
NotNil(ii, t)
var fi struct {
x func(t *testing.T)
}
Nil(fi, t)
fi.x = TestIsNil
NotNil(fi, t)
}
// Indirect returns the value that v points to.
// If v is a nil pointer, Indirect returns a zero Value.
// If v is not a pointer, Indirect returns v.
func Indirect(v Value) Value {
if v.Kind() != Ptr {
return v
}
return v.Elem()
}
func TestNilPtrValueSub(t *testing.T) {
var pi *int
if pv := ValueOf(pi); pv.Elem().IsValid() {
t.Error("ValueOf((*int)(nil)).Elem().IsValid()")
}
}
type Point struct {
x, y int
}
// This will be index 0.
func (p Point) AnotherMethod(scale int) int {
return -1
}
// This will be index 1.
func (p Point) Dist(scale int) int {
//println("Point.Dist", p.x, p.y, scale)
return p.x*p.x*scale + p.y*p.y*scale
}
// This will be index 2.
func (p Point) GCMethod(k int) int {
runtime.GC()
return k + p.x
}
// This will be index 3.
func (p Point) NoArgs() {
// Exercise no-argument/no-result paths.
}
// This will be index 4.
func (p Point) TotalDist(points ...Point) int {
tot := 0
for _, q := range points {
dx := q.x - p.x
dy := q.y - p.y
tot += dx*dx + dy*dy // Should call Sqrt, but it's just a test.
}
return tot
}
type D1 struct {
d int
}
type D2 struct {
d int
}
func TestImportPath(t *testing.T) {
tests := []struct {
t Type
path string
}{
{TypeOf(&base64.Encoding{}).Elem(), "encoding/base64"},
{TypeOf(int(0)), ""},
{TypeOf(int8(0)), ""},
{TypeOf(int16(0)), ""},
{TypeOf(int32(0)), ""},
{TypeOf(int64(0)), ""},
{TypeOf(uint(0)), ""},
{TypeOf(uint8(0)), ""},
{TypeOf(uint16(0)), ""},
{TypeOf(uint32(0)), ""},
{TypeOf(uint64(0)), ""},
{TypeOf(uintptr(0)), ""},
{TypeOf(float32(0)), ""},
{TypeOf(float64(0)), ""},
{TypeOf(complex64(0)), ""},
{TypeOf(complex128(0)), ""},
{TypeOf(byte(0)), ""},
{TypeOf(rune(0)), ""},
{TypeOf([]byte(nil)), ""},
{TypeOf([]rune(nil)), ""},
{TypeOf(string("")), ""},
{TypeOf((*interface{})(nil)).Elem(), ""},
{TypeOf((*byte)(nil)), ""},
{TypeOf((*rune)(nil)), ""},
{TypeOf((*int64)(nil)), ""},
{TypeOf(map[string]int{}), ""},
{TypeOf((*error)(nil)).Elem(), ""},
{TypeOf((*Point)(nil)), ""},
{TypeOf((*Point)(nil)).Elem(), "internal/reflectlite_test"},
}
for _, test := range tests {
if path := test.t.PkgPath(); path != test.path {
t.Errorf("%v.PkgPath() = %q, want %q", test.t, path, test.path)
}
}
}
func noAlloc(t *testing.T, n int, f func(int)) {
if testing.Short() {
t.Skip("skipping malloc count in short mode")
}
if runtime.GOMAXPROCS(0) > 1 {
t.Skip("skipping; GOMAXPROCS>1")
}
i := -1
allocs := testing.AllocsPerRun(n, func() {
f(i)
i++
})
if allocs > 0 {
t.Errorf("%d iterations: got %v mallocs, want 0", n, allocs)
}
}
func TestAllocations(t *testing.T) {
noAlloc(t, 100, func(j int) {
var i interface{}
var v Value
// We can uncomment this when compiler escape analysis
// is good enough to see that the integer assigned to i
// does not escape and therefore need not be allocated.
//
// i = 42 + j
// v = ValueOf(i)
// if int(v.Int()) != 42+j {
// panic("wrong int")
// }
i = func(j int) int { return j }
v = ValueOf(i)
if ToInterface(v).(func(int) int)(j) != j {
panic("wrong result")
}
})
}
func TestSetPanic(t *testing.T) {
ok := func(f func()) { f() }
bad := shouldPanic
clear := func(v Value) { v.Set(Zero(v.Type())) }
type t0 struct {
W int
}
type t1 struct {
Y int
t0
}
type T2 struct {
Z int
namedT0 t0
}
type T struct {
X int
t1
T2
NamedT1 t1
NamedT2 T2
namedT1 t1
namedT2 T2
}
// not addressable
v := ValueOf(T{})
bad(func() { clear(Field(v, 0)) }) // .X
bad(func() { clear(Field(v, 1)) }) // .t1
bad(func() { clear(Field(Field(v, 1), 0)) }) // .t1.Y
bad(func() { clear(Field(Field(v, 1), 1)) }) // .t1.t0
bad(func() { clear(Field(Field(Field(v, 1), 1), 0)) }) // .t1.t0.W
bad(func() { clear(Field(v, 2)) }) // .T2
bad(func() { clear(Field(Field(v, 2), 0)) }) // .T2.Z
bad(func() { clear(Field(Field(v, 2), 1)) }) // .T2.namedT0
bad(func() { clear(Field(Field(Field(v, 2), 1), 0)) }) // .T2.namedT0.W
bad(func() { clear(Field(v, 3)) }) // .NamedT1
bad(func() { clear(Field(Field(v, 3), 0)) }) // .NamedT1.Y
bad(func() { clear(Field(Field(v, 3), 1)) }) // .NamedT1.t0
bad(func() { clear(Field(Field(Field(v, 3), 1), 0)) }) // .NamedT1.t0.W
bad(func() { clear(Field(v, 4)) }) // .NamedT2
bad(func() { clear(Field(Field(v, 4), 0)) }) // .NamedT2.Z
bad(func() { clear(Field(Field(v, 4), 1)) }) // .NamedT2.namedT0
bad(func() { clear(Field(Field(Field(v, 4), 1), 0)) }) // .NamedT2.namedT0.W
bad(func() { clear(Field(v, 5)) }) // .namedT1
bad(func() { clear(Field(Field(v, 5), 0)) }) // .namedT1.Y
bad(func() { clear(Field(Field(v, 5), 1)) }) // .namedT1.t0
bad(func() { clear(Field(Field(Field(v, 5), 1), 0)) }) // .namedT1.t0.W
bad(func() { clear(Field(v, 6)) }) // .namedT2
bad(func() { clear(Field(Field(v, 6), 0)) }) // .namedT2.Z
bad(func() { clear(Field(Field(v, 6), 1)) }) // .namedT2.namedT0
bad(func() { clear(Field(Field(Field(v, 6), 1), 0)) }) // .namedT2.namedT0.W
// addressable
v = ValueOf(&T{}).Elem()
ok(func() { clear(Field(v, 0)) }) // .X
bad(func() { clear(Field(v, 1)) }) // .t1
ok(func() { clear(Field(Field(v, 1), 0)) }) // .t1.Y
bad(func() { clear(Field(Field(v, 1), 1)) }) // .t1.t0
ok(func() { clear(Field(Field(Field(v, 1), 1), 0)) }) // .t1.t0.W
ok(func() { clear(Field(v, 2)) }) // .T2
ok(func() { clear(Field(Field(v, 2), 0)) }) // .T2.Z
bad(func() { clear(Field(Field(v, 2), 1)) }) // .T2.namedT0
bad(func() { clear(Field(Field(Field(v, 2), 1), 0)) }) // .T2.namedT0.W
ok(func() { clear(Field(v, 3)) }) // .NamedT1
ok(func() { clear(Field(Field(v, 3), 0)) }) // .NamedT1.Y
bad(func() { clear(Field(Field(v, 3), 1)) }) // .NamedT1.t0
ok(func() { clear(Field(Field(Field(v, 3), 1), 0)) }) // .NamedT1.t0.W
ok(func() { clear(Field(v, 4)) }) // .NamedT2
ok(func() { clear(Field(Field(v, 4), 0)) }) // .NamedT2.Z
bad(func() { clear(Field(Field(v, 4), 1)) }) // .NamedT2.namedT0
bad(func() { clear(Field(Field(Field(v, 4), 1), 0)) }) // .NamedT2.namedT0.W
bad(func() { clear(Field(v, 5)) }) // .namedT1
bad(func() { clear(Field(Field(v, 5), 0)) }) // .namedT1.Y
bad(func() { clear(Field(Field(v, 5), 1)) }) // .namedT1.t0
bad(func() { clear(Field(Field(Field(v, 5), 1), 0)) }) // .namedT1.t0.W
bad(func() { clear(Field(v, 6)) }) // .namedT2
bad(func() { clear(Field(Field(v, 6), 0)) }) // .namedT2.Z
bad(func() { clear(Field(Field(v, 6), 1)) }) // .namedT2.namedT0
bad(func() { clear(Field(Field(Field(v, 6), 1), 0)) }) // .namedT2.namedT0.W
}
func shouldPanic(f func()) {
defer func() {
if recover() == nil {
panic("did not panic")
}
}()
f()
}
type S struct {
i1 int64
i2 int64
}
func TestBigZero(t *testing.T) {
const size = 1 << 10
var v [size]byte
z := ToInterface(Zero(ValueOf(v).Type())).([size]byte)
for i := 0; i < size; i++ {
if z[i] != 0 {
t.Fatalf("Zero object not all zero, index %d", i)
}
}
}
func TestInvalid(t *testing.T) {
// Used to have inconsistency between IsValid() and Kind() != Invalid.
type T struct{ v interface{} }
v := Field(ValueOf(T{}), 0)
if v.IsValid() != true || v.Kind() != Interface {
t.Errorf("field: IsValid=%v, Kind=%v, want true, Interface", v.IsValid(), v.Kind())
}
v = v.Elem()
if v.IsValid() != false || v.Kind() != Invalid {
t.Errorf("field elem: IsValid=%v, Kind=%v, want false, Invalid", v.IsValid(), v.Kind())
}
}
type TheNameOfThisTypeIsExactly255BytesLongSoWhenTheCompilerPrependsTheReflectTestPackageNameAndExtraStarTheLinkerRuntimeAndReflectPackagesWillHaveToCorrectlyDecodeTheSecondLengthByte0123456789_0123456789_0123456789_0123456789_0123456789_012345678 int
type nameTest struct {
v interface{}
want string
}
var nameTests = []nameTest{
{(*int32)(nil), "int32"},
{(*D1)(nil), "D1"},
{(*[]D1)(nil), ""},
{(*chan D1)(nil), ""},
{(*func() D1)(nil), ""},
{(*<-chan D1)(nil), ""},
{(*chan<- D1)(nil), ""},
{(*interface{})(nil), ""},
{(*interface {
F()
})(nil), ""},
{(*TheNameOfThisTypeIsExactly255BytesLongSoWhenTheCompilerPrependsTheReflectTestPackageNameAndExtraStarTheLinkerRuntimeAndReflectPackagesWillHaveToCorrectlyDecodeTheSecondLengthByte0123456789_0123456789_0123456789_0123456789_0123456789_012345678)(nil), "TheNameOfThisTypeIsExactly255BytesLongSoWhenTheCompilerPrependsTheReflectTestPackageNameAndExtraStarTheLinkerRuntimeAndReflectPackagesWillHaveToCorrectlyDecodeTheSecondLengthByte0123456789_0123456789_0123456789_0123456789_0123456789_012345678"},
}
func TestNames(t *testing.T) {
for _, test := range nameTests {
typ := TypeOf(test.v).Elem()
if got := typ.Name(); got != test.want {
t.Errorf("%v Name()=%q, want %q", typ, got, test.want)
}
}
}
type embed struct {
EmbedWithUnexpMeth
}
func TestNameBytesAreAligned(t *testing.T) {
typ := TypeOf(embed{})
b := FirstMethodNameBytes(typ)
v := uintptr(unsafe.Pointer(b))
if v%unsafe.Alignof((*byte)(nil)) != 0 {
t.Errorf("reflect.name.bytes pointer is not aligned: %x", v)
}
}
// TestUnaddressableField tests that the reflect package will not allow
// a type from another package to be used as a named type with an
// unexported field.
//
// This ensures that unexported fields cannot be modified by other packages.
func TestUnaddressableField(t *testing.T) {
var b Buffer // type defined in reflect, a different package
var localBuffer struct {
buf []byte
}
lv := ValueOf(&localBuffer).Elem()
rv := ValueOf(b)
shouldPanic(func() {
lv.Set(rv)
})
}
type Tint int
type Tint2 = Tint
type Talias1 struct {
byte
uint8
int
int32
rune
}
type Talias2 struct {
Tint
Tint2
}
func TestAliasNames(t *testing.T) {
t1 := Talias1{byte: 1, uint8: 2, int: 3, int32: 4, rune: 5}
out := fmt.Sprintf("%#v", t1)
want := "reflectlite_test.Talias1{byte:0x1, uint8:0x2, int:3, int32:4, rune:5}"
if out != want {
t.Errorf("Talias1 print:\nhave: %s\nwant: %s", out, want)
}
t2 := Talias2{Tint: 1, Tint2: 2}
out = fmt.Sprintf("%#v", t2)
want = "reflectlite_test.Talias2{Tint:1, Tint2:2}"
if out != want {
t.Errorf("Talias2 print:\nhave: %s\nwant: %s", out, want)
}
}
src/internal/reflectlite/asm.s 0 → 100644
View file @ 9650726e
// Copyright 2019 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.
// Trigger build without complete flag.
\ No newline at end of file
src/internal/reflectlite/export_test.go 0 → 100644
View file @ 9650726e
// Copyright 2019 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.
package reflectlite
import (
"unsafe"
)
// Field returns the i'th field of the struct v.
// It panics if v's Kind is not Struct or i is out of range.
func Field(v Value, i int) Value {
if v.kind() != Struct {
panic(&ValueError{"reflect.Value.Field", v.kind()})
}
tt := (*structType)(unsafe.Pointer(v.typ))
if uint(i) >= uint(len(tt.fields)) {
panic("reflect: Field index out of range")
}
field := &tt.fields[i]
typ := field.typ
// Inherit permission bits from v, but clear flagEmbedRO.
fl := v.flag&(flagStickyRO|flagIndir|flagAddr) | flag(typ.Kind())
// Using an unexported field forces flagRO.
if !field.name.isExported() {
if field.embedded() {
fl |= flagEmbedRO
} else {
fl |= flagStickyRO
}
}
// Either flagIndir is set and v.ptr points at struct,
// or flagIndir is not set and v.ptr is the actual struct data.
// In the former case, we want v.ptr + offset.
// In the latter case, we must have field.offset = 0,
// so v.ptr + field.offset is still the correct address.
ptr := add(v.ptr, field.offset(), "same as non-reflect &v.field")
return Value{typ, ptr, fl}
}
func TField(typ Type, i int) Type {
t := typ.(*rtype)
if t.Kind() != Struct {
panic("reflect: Field of non-struct type")
}
tt := (*structType)(unsafe.Pointer(t))
return StructFieldType(tt, i)
}
// Field returns the i'th struct field.
func StructFieldType(t *structType, i int) Type {
if i < 0 || i >= len(t.fields) {
panic("reflect: Field index out of bounds")
}
p := &t.fields[i]
return toType(p.typ)
}
// Zero returns a Value representing the zero value for the specified type.
// The result is different from the zero value of the Value struct,
// which represents no value at all.
// For example, Zero(TypeOf(42)) returns a Value with Kind Int and value 0.
// The returned value is neither addressable nor settable.
func Zero(typ Type) Value {
if typ == nil {
panic("reflect: Zero(nil)")
}
t := typ.(*rtype)
fl := flag(t.Kind())
if ifaceIndir(t) {
return Value{t, unsafe_New(t), fl | flagIndir}
}
return Value{t, nil, fl}
}
// ToInterface returns v's current value as an interface{}.
// It is equivalent to:
// var i interface{} = (v's underlying value)
// It panics if the Value was obtained by accessing
// unexported struct fields.
func ToInterface(v Value) (i interface{}) {
return valueInterface(v)
}
type EmbedWithUnexpMeth struct{}
func (EmbedWithUnexpMeth) f() {}
type pinUnexpMeth interface {
f()
}
var pinUnexpMethI = pinUnexpMeth(EmbedWithUnexpMeth{})
func FirstMethodNameBytes(t Type) *byte {
_ = pinUnexpMethI
ut := t.uncommon()
if ut == nil {
panic("type has no methods")
}
m := ut.methods()[0]
mname := t.(*rtype).nameOff(m.name)
if *mname.data(0, "name flag field")&(1<<2) == 0 {
panic("method name does not have pkgPath *string")
}
return mname.bytes
}
type Buffer struct {
buf []byte
}
src/internal/reflectlite/set_test.go 0 → 100644
View file @ 9650726e
// Copyright 2011 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.
package reflectlite_test
import (
"bytes"
"go/ast"
"go/token"
. "internal/reflectlite"
"io"
"testing"
)
func TestImplicitSetConversion(t *testing.T) {
// Assume TestImplicitMapConversion covered the basics.
// Just make sure conversions are being applied at all.
var r io.Reader
b := new(bytes.Buffer)
rv := ValueOf(&r).Elem()
rv.Set(ValueOf(b))
if r != b {
t.Errorf("after Set: r=%T(%v)", r, r)
}
}
var implementsTests = []struct {
x interface{}
t interface{}
b bool
}{
{new(*bytes.Buffer), new(io.Reader), true},
{new(bytes.Buffer), new(io.Reader), false},
{new(*bytes.Buffer), new(io.ReaderAt), false},
{new(*ast.Ident), new(ast.Expr), true},
{new(*notAnExpr), new(ast.Expr), false},
{new(*ast.Ident), new(notASTExpr), false},
{new(notASTExpr), new(ast.Expr), false},
{new(ast.Expr), new(notASTExpr), false},
{new(*notAnExpr), new(notASTExpr), true},
}
type notAnExpr struct{}
func (notAnExpr) Pos() token.Pos { return token.NoPos }
func (notAnExpr) End() token.Pos { return token.NoPos }
func (notAnExpr) exprNode() {}
type notASTExpr interface {
Pos() token.Pos
End() token.Pos
exprNode()
}
func TestImplements(t *testing.T) {
for _, tt := range implementsTests {
xv := TypeOf(tt.x).Elem()
xt := TypeOf(tt.t).Elem()
if b := xv.Implements(xt); b != tt.b {
t.Errorf("(%s).Implements(%s) = %v, want %v", TypeString(xv), TypeString(xt), b, tt.b)
}
}
}
var assignableTests = []struct {
x interface{}
t interface{}
b bool
}{
{new(chan int), new(<-chan int), true},
{new(<-chan int), new(chan int), false},
{new(*int), new(IntPtr), true},
{new(IntPtr), new(*int), true},
{new(IntPtr), new(IntPtr1), false},
{new(Ch), new(<-chan interface{}), true},
// test runs implementsTests too
}
type IntPtr *int
type IntPtr1 *int
type Ch <-chan interface{}
func TestAssignableTo(t *testing.T) {
for i, tt := range append(assignableTests, implementsTests...) {
xv := TypeOf(tt.x).Elem()
xt := TypeOf(tt.t).Elem()
if b := xv.AssignableTo(xt); b != tt.b {
t.Errorf("%d:AssignableTo: got %v, want %v", i, b, tt.b)
}
}
}
src/internal/reflectlite/tostring_test.go 0 → 100644
View file @ 9650726e
// Copyright 2009 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.
// Formatting of reflection types and values for debugging.
// Not defined as methods so they do not need to be linked into most binaries;
// the functions are not used by the library itself, only in tests.
package reflectlite_test
import (
. "internal/reflectlite"
"reflect"
"strconv"
)
// valueToString returns a textual representation of the reflection value val.
// For debugging only.
func valueToString(v Value) string {
return valueToStringImpl(reflect.ValueOf(ToInterface(v)))
}
func valueToStringImpl(val reflect.Value) string {
var str string
if !val.IsValid() {
return "<zero Value>"
}
typ := val.Type()
switch val.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return strconv.FormatInt(val.Int(), 10)
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
return strconv.FormatUint(val.Uint(), 10)
case reflect.Float32, reflect.Float64:
return strconv.FormatFloat(val.Float(), 'g', -1, 64)
case reflect.Complex64, reflect.Complex128:
c := val.Complex()
return strconv.FormatFloat(real(c), 'g', -1, 64) + "+" + strconv.FormatFloat(imag(c), 'g', -1, 64) + "i"
case reflect.String:
return val.String()
case reflect.Bool:
if val.Bool() {
return "true"
} else {
return "false"
}
case reflect.Ptr:
v := val
str = typ.String() + "("
if v.IsNil() {
str += "0"
} else {
str += "&" + valueToStringImpl(v.Elem())
}
str += ")"
return str
case reflect.Array, reflect.Slice:
v := val
str += typ.String()
str += "{"
for i := 0; i < v.Len(); i++ {
if i > 0 {
str += ", "
}
str += valueToStringImpl(v.Index(i))
}
str += "}"
return str
case reflect.Map:
str += typ.String()
str += "{"
str += "<can't iterate on maps>"
str += "}"
return str
case reflect.Chan:
str = typ.String()
return str
case reflect.Struct:
t := typ
v := val
str += t.String()
str += "{"
for i, n := 0, v.NumField(); i < n; i++ {
if i > 0 {
str += ", "
}
str += valueToStringImpl(v.Field(i))
}
str += "}"
return str
case reflect.Interface:
return typ.String() + "(" + valueToStringImpl(val.Elem()) + ")"
case reflect.Func:
return typ.String() + "(arg)"
default:
panic("valueToString: can't print type " + typ.String())
}
}
src/internal/reflectlite/type.go 0 → 100644
View file @ 9650726e
// Copyright 2009 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.
// Package reflectlite implements lightweight version of reflect, not using
// any package except for "runtime" and "unsafe".
package reflectlite
import (
"unsafe"
)
// Type is the representation of a Go type.
//
// Not all methods apply to all kinds of types. Restrictions,
// if any, are noted in the documentation for each method.
// Use the Kind method to find out the kind of type before
// calling kind-specific methods. Calling a method
// inappropriate to the kind of type causes a run-time panic.
//
// Type values are comparable, such as with the == operator,
// so they can be used as map keys.
// Two Type values are equal if they represent identical types.
type Type interface {
// Methods applicable to all types.
// Name returns the type's name within its package for a defined type.
// For other (non-defined) types it returns the empty string.
Name() string
// PkgPath returns a defined type's package path, that is, the import path
// that uniquely identifies the package, such as "encoding/base64".
// If the type was predeclared (string, error) or not defined (*T, struct{},
// []int, or A where A is an alias for a non-defined type), the package path
// will be the empty string.
PkgPath() string
// Kind returns the specific kind of this type.
Kind() Kind
// Implements reports whether the type implements the interface type u.
Implements(u Type) bool
// AssignableTo reports whether a value of the type is assignable to type u.
AssignableTo(u Type) bool
// Elem returns a type's element type.
// It panics if the type's Kind is not Ptr.
Elem() Type
common() *rtype
uncommon() *uncommonType
}
/*
* These data structures are known to the compiler (../../cmd/internal/gc/reflect.go).
* A few are known to ../runtime/type.go to convey to debuggers.
* They are also known to ../runtime/type.go.
*/
// A Kind represents the specific kind of type that a Type represents.
// The zero Kind is not a valid kind.
type Kind uint
const (
Invalid Kind = iota
Bool
Int
Int8
Int16
Int32
Int64
Uint
Uint8
Uint16
Uint32
Uint64
Uintptr
Float32
Float64
Complex64
Complex128
Array
Chan
Func
Interface
Map
Ptr
Slice
String
Struct
UnsafePointer
)
// tflag is used by an rtype to signal what extra type information is
// available in the memory directly following the rtype value.
//
// tflag values must be kept in sync with copies in:
// cmd/compile/internal/gc/reflect.go
// cmd/link/internal/ld/decodesym.go
// runtime/type.go
type tflag uint8
const (
// tflagUncommon means that there is a pointer, *uncommonType,
// just beyond the outer type structure.
//
// For example, if t.Kind() == Struct and t.tflag&tflagUncommon != 0,
// then t has uncommonType data and it can be accessed as:
//
// type tUncommon struct {
// structType
// u uncommonType
// }
// u := &(*tUncommon)(unsafe.Pointer(t)).u
tflagUncommon tflag = 1 << 0
// tflagExtraStar means the name in the str field has an
// extraneous '*' prefix. This is because for most types T in
// a program, the type *T also exists and reusing the str data
// saves binary size.
tflagExtraStar tflag = 1 << 1
// tflagNamed means the type has a name.
tflagNamed tflag = 1 << 2
)
// rtype is the common implementation of most values.
// It is embedded in other struct types.
//
// rtype must be kept in sync with ../runtime/type.go:/^type._type.
type rtype struct {
size uintptr
ptrdata uintptr // number of bytes in the type that can contain pointers
hash uint32 // hash of type; avoids computation in hash tables
tflag tflag // extra type information flags
align uint8 // alignment of variable with this type
fieldAlign uint8 // alignment of struct field with this type
kind uint8 // enumeration for C
alg *typeAlg // algorithm table
gcdata *byte // garbage collection data
str nameOff // string form
ptrToThis typeOff // type for pointer to this type, may be zero
}
// a copy of runtime.typeAlg
type typeAlg struct {
// function for hashing objects of this type
// (ptr to object, seed) -> hash
hash func(unsafe.Pointer, uintptr) uintptr
// function for comparing objects of this type
// (ptr to object A, ptr to object B) -> ==?
equal func(unsafe.Pointer, unsafe.Pointer) bool
}
// Method on non-interface type
type method struct {
name nameOff // name of method
mtyp typeOff // method type (without receiver)
ifn textOff // fn used in interface call (one-word receiver)
tfn textOff // fn used for normal method call
}
// uncommonType is present only for defined types or types with methods
// (if T is a defined type, the uncommonTypes for T and *T have methods).
// Using a pointer to this struct reduces the overall size required
// to describe a non-defined type with no methods.
type uncommonType struct {
pkgPath nameOff // import path; empty for built-in types like int, string
mcount uint16 // number of methods
xcount uint16 // number of exported methods
moff uint32 // offset from this uncommontype to [mcount]method
_ uint32 // unused
}
// chanDir represents a channel type's direction.
type chanDir int
const (
recvDir chanDir = 1 << iota // <-chan
sendDir // chan<-
bothDir = recvDir | sendDir // chan
)
// arrayType represents a fixed array type.
type arrayType struct {
rtype
elem *rtype // array element type
slice *rtype // slice type
len uintptr
}
// chanType represents a channel type.
type chanType struct {
rtype
elem *rtype // channel element type
dir uintptr // channel direction (chanDir)
}
// funcType represents a function type.
//
// A *rtype for each in and out parameter is stored in an array that
// directly follows the funcType (and possibly its uncommonType). So
// a function type with one method, one input, and one output is:
//
// struct {
// funcType
// uncommonType
// [2]*rtype // [0] is in, [1] is out
// }
type funcType struct {
rtype
inCount uint16
outCount uint16 // top bit is set if last input parameter is ...
}
// imethod represents a method on an interface type
type imethod struct {
name nameOff // name of method
typ typeOff // .(*FuncType) underneath
}
// interfaceType represents an interface type.
type interfaceType struct {
rtype
pkgPath name // import path
methods []imethod // sorted by hash
}
// mapType represents a map type.
type mapType struct {
rtype
key *rtype // map key type
elem *rtype // map element (value) type
keysize uint8 // size of key slot
valuesize uint8 // size of value slot
bucketsize uint16 // size of bucket
flags uint32
}
// ptrType represents a pointer type.
type ptrType struct {
rtype
elem *rtype // pointer element (pointed at) type
}
// sliceType represents a slice type.
type sliceType struct {
rtype
elem *rtype // slice element type
}
// Struct field
type structField struct {
name name // name is always non-empty
typ *rtype // type of field
offsetEmbed uintptr // byte offset of field<<1 | isEmbedded
}
func (f *structField) offset() uintptr {
return f.offsetEmbed >> 1
}
func (f *structField) embedded() bool {
return f.offsetEmbed&1 != 0
}
// structType represents a struct type.
type structType struct {
rtype
pkgPath name
fields []structField // sorted by offset
}
// name is an encoded type name with optional extra data.
//
// The first byte is a bit field containing:
//
// 1<<0 the name is exported
// 1<<1 tag data follows the name
// 1<<2 pkgPath nameOff follows the name and tag
//
// The next two bytes are the data length:
//
// l := uint16(data[1])<<8 | uint16(data[2])
//
// Bytes [3:3+l] are the string data.
//
// If tag data follows then bytes 3+l and 3+l+1 are the tag length,
// with the data following.
//
// If the import path follows, then 4 bytes at the end of
// the data form a nameOff. The import path is only set for concrete
// methods that are defined in a different package than their type.
//
// If a name starts with "*", then the exported bit represents
// whether the pointed to type is exported.
type name struct {
bytes *byte
}
func (n name) data(off int, whySafe string) *byte {
return (*byte)(add(unsafe.Pointer(n.bytes), uintptr(off), whySafe))
}
func (n name) isExported() bool {
return (*n.bytes)&(1<<0) != 0
}
func (n name) nameLen() int {
return int(uint16(*n.data(1, "name len field"))<<8 | uint16(*n.data(2, "name len field")))
}
func (n name) tagLen() int {
if *n.data(0, "name flag field")&(1<<1) == 0 {
return 0
}
off := 3 + n.nameLen()
return int(uint16(*n.data(off, "name taglen field"))<<8 | uint16(*n.data(off+1, "name taglen field")))
}
func (n name) name() (s string) {
if n.bytes == nil {
return
}
b := (*[4]byte)(unsafe.Pointer(n.bytes))
hdr := (*stringHeader)(unsafe.Pointer(&s))
hdr.Data = unsafe.Pointer(&b[3])
hdr.Len = int(b[1])<<8 | int(b[2])
return s
}
func (n name) tag() (s string) {
tl := n.tagLen()
if tl == 0 {
return ""
}
nl := n.nameLen()
hdr := (*stringHeader)(unsafe.Pointer(&s))
hdr.Data = unsafe.Pointer(n.data(3+nl+2, "non-empty string"))
hdr.Len = tl
return s
}
func (n name) pkgPath() string {
if n.bytes == nil || *n.data(0, "name flag field")&(1<<2) == 0 {
return ""
}
off := 3 + n.nameLen()
if tl := n.tagLen(); tl > 0 {
off += 2 + tl
}
var nameOff int32
// Note that this field may not be aligned in memory,
// so we cannot use a direct int32 assignment here.
copy((*[4]byte)(unsafe.Pointer(&nameOff))[:], (*[4]byte)(unsafe.Pointer(n.data(off, "name offset field")))[:])
pkgPathName := name{(*byte)(resolveTypeOff(unsafe.Pointer(n.bytes), nameOff))}
return pkgPathName.name()
}
/*
* The compiler knows the exact layout of all the data structures above.
* The compiler does not know about the data structures and methods below.
*/
const (
kindDirectIface = 1 << 5
kindGCProg = 1 << 6 // Type.gc points to GC program
kindNoPointers = 1 << 7
kindMask = (1 << 5) - 1
)
func (t *uncommonType) methods() []method {
if t.mcount == 0 {
return nil
}
return (*[1 << 16]method)(add(unsafe.Pointer(t), uintptr(t.moff), "t.mcount > 0"))[:t.mcount:t.mcount]
}
func (t *uncommonType) exportedMethods() []method {
if t.xcount == 0 {
return nil
}
return (*[1 << 16]method)(add(unsafe.Pointer(t), uintptr(t.moff), "t.xcount > 0"))[:t.xcount:t.xcount]
}
// resolveNameOff resolves a name offset from a base pointer.
// The (*rtype).nameOff method is a convenience wrapper for this function.
// Implemented in the runtime package.
func resolveNameOff(ptrInModule unsafe.Pointer, off int32) unsafe.Pointer
// resolveTypeOff resolves an *rtype offset from a base type.
// The (*rtype).typeOff method is a convenience wrapper for this function.
// Implemented in the runtime package.
func resolveTypeOff(rtype unsafe.Pointer, off int32) unsafe.Pointer
type nameOff int32 // offset to a name
type typeOff int32 // offset to an *rtype
type textOff int32 // offset from top of text section
func (t *rtype) nameOff(off nameOff) name {
return name{(*byte)(resolveNameOff(unsafe.Pointer(t), int32(off)))}
}
func (t *rtype) typeOff(off typeOff) *rtype {
return (*rtype)(resolveTypeOff(unsafe.Pointer(t), int32(off)))
}
func (t *rtype) uncommon() *uncommonType {
if t.tflag&tflagUncommon == 0 {
return nil
}
switch t.Kind() {
case Struct:
return &(*structTypeUncommon)(unsafe.Pointer(t)).u
case Ptr:
type u struct {
ptrType
u uncommonType
}
return &(*u)(unsafe.Pointer(t)).u
case Func:
type u struct {
funcType
u uncommonType
}
return &(*u)(unsafe.Pointer(t)).u
case Slice:
type u struct {
sliceType
u uncommonType
}
return &(*u)(unsafe.Pointer(t)).u
case Array:
type u struct {
arrayType
u uncommonType
}
return &(*u)(unsafe.Pointer(t)).u
case Chan:
type u struct {
chanType
u uncommonType
}
return &(*u)(unsafe.Pointer(t)).u
case Map:
type u struct {
mapType
u uncommonType
}
return &(*u)(unsafe.Pointer(t)).u
case Interface:
type u struct {
interfaceType
u uncommonType
}
return &(*u)(unsafe.Pointer(t)).u
default:
type u struct {
rtype
u uncommonType
}
return &(*u)(unsafe.Pointer(t)).u
}
}
func (t *rtype) String() string {
s := t.nameOff(t.str).name()
if t.tflag&tflagExtraStar != 0 {
return s[1:]
}
return s
}
func (t *rtype) Kind() Kind { return Kind(t.kind & kindMask) }
func (t *rtype) common() *rtype { return t }
func (t *rtype) exportedMethods() []method {
ut := t.uncommon()
if ut == nil {
return nil
}
return ut.exportedMethods()
}
func (t *rtype) NumMethod() int {
if t.Kind() == Interface {
tt := (*interfaceType)(unsafe.Pointer(t))
return tt.NumMethod()
}
return len(t.exportedMethods())
}
func (t *rtype) PkgPath() string {
if t.tflag&tflagNamed == 0 {
return ""
}
ut := t.uncommon()
if ut == nil {
return ""
}
return t.nameOff(ut.pkgPath).name()
}
func (t *rtype) Name() string {
if t.tflag&tflagNamed == 0 {
return ""
}
s := t.String()
i := len(s) - 1
for i >= 0 {
if s[i] == '.' {
break
}
i--
}
return s[i+1:]
}
func (t *rtype) chanDir() chanDir {
if t.Kind() != Chan {
panic("reflect: chanDir of non-chan type")
}
tt := (*chanType)(unsafe.Pointer(t))
return chanDir(tt.dir)
}
func (t *rtype) Elem() Type {
switch t.Kind() {
case Array:
tt := (*arrayType)(unsafe.Pointer(t))
return toType(tt.elem)
case Chan:
tt := (*chanType)(unsafe.Pointer(t))
return toType(tt.elem)
case Map:
tt := (*mapType)(unsafe.Pointer(t))
return toType(tt.elem)
case Ptr:
tt := (*ptrType)(unsafe.Pointer(t))
return toType(tt.elem)
case Slice:
tt := (*sliceType)(unsafe.Pointer(t))
return toType(tt.elem)
}
panic("reflect: Elem of invalid type")
}
func (t *rtype) In(i int) Type {
if t.Kind() != Func {
panic("reflect: In of non-func type")
}
tt := (*funcType)(unsafe.Pointer(t))
return toType(tt.in()[i])
}
func (t *rtype) Key() Type {
if t.Kind() != Map {
panic("reflect: Key of non-map type")
}
tt := (*mapType)(unsafe.Pointer(t))
return toType(tt.key)
}
func (t *rtype) Len() int {
if t.Kind() != Array {
panic("reflect: Len of non-array type")
}
tt := (*arrayType)(unsafe.Pointer(t))
return int(tt.len)
}
func (t *rtype) NumField() int {
if t.Kind() != Struct {
panic("reflect: NumField of non-struct type")
}
tt := (*structType)(unsafe.Pointer(t))
return len(tt.fields)
}
func (t *rtype) NumIn() int {
if t.Kind() != Func {
panic("reflect: NumIn of non-func type")
}
tt := (*funcType)(unsafe.Pointer(t))
return int(tt.inCount)
}
func (t *rtype) NumOut() int {
if t.Kind() != Func {
panic("reflect: NumOut of non-func type")
}
tt := (*funcType)(unsafe.Pointer(t))
return len(tt.out())
}
func (t *rtype) Out(i int) Type {
if t.Kind() != Func {
panic("reflect: Out of non-func type")
}
tt := (*funcType)(unsafe.Pointer(t))
return toType(tt.out()[i])
}
func (t *funcType) in() []*rtype {
uadd := unsafe.Sizeof(*t)
if t.tflag&tflagUncommon != 0 {
uadd += unsafe.Sizeof(uncommonType{})
}
if t.inCount == 0 {
return nil
}
return (*[1 << 20]*rtype)(add(unsafe.Pointer(t), uadd, "t.inCount > 0"))[:t.inCount]
}
func (t *funcType) out() []*rtype {
uadd := unsafe.Sizeof(*t)
if t.tflag&tflagUncommon != 0 {
uadd += unsafe.Sizeof(uncommonType{})
}
outCount := t.outCount & (1<<15 - 1)
if outCount == 0 {
return nil
}
return (*[1 << 20]*rtype)(add(unsafe.Pointer(t), uadd, "outCount > 0"))[t.inCount : t.inCount+outCount]
}
// add returns p+x.
//
// The whySafe string is ignored, so that the function still inlines
// as efficiently as p+x, but all call sites should use the string to
// record why the addition is safe, which is to say why the addition
// does not cause x to advance to the very end of p's allocation
// and therefore point incorrectly at the next block in memory.
func add(p unsafe.Pointer, x uintptr, whySafe string) unsafe.Pointer {
return unsafe.Pointer(uintptr(p) + x)
}
// NumMethod returns the number of interface methods in the type's method set.
func (t *interfaceType) NumMethod() int { return len(t.methods) }
// TypeOf returns the reflection Type that represents the dynamic type of i.
// If i is a nil interface value, TypeOf returns nil.
func TypeOf(i interface{}) Type {
eface := *(*emptyInterface)(unsafe.Pointer(&i))
return toType(eface.typ)
}
func (t *rtype) Implements(u Type) bool {
if u == nil {
panic("reflect: nil type passed to Type.Implements")
}
if u.Kind() != Interface {
panic("reflect: non-interface type passed to Type.Implements")
}
return implements(u.(*rtype), t)
}
func (t *rtype) AssignableTo(u Type) bool {
if u == nil {
panic("reflect: nil type passed to Type.AssignableTo")
}
uu := u.(*rtype)
return directlyAssignable(uu, t) || implements(uu, t)
}
// implements reports whether the type V implements the interface type T.
func implements(T, V *rtype) bool {
if T.Kind() != Interface {
return false
}
t := (*interfaceType)(unsafe.Pointer(T))
if len(t.methods) == 0 {
return true
}
// The same algorithm applies in both cases, but the
// method tables for an interface type and a concrete type
// are different, so the code is duplicated.
// In both cases the algorithm is a linear scan over the two
// lists - T's methods and V's methods - simultaneously.
// Since method tables are stored in a unique sorted order
// (alphabetical, with no duplicate method names), the scan
// through V's methods must hit a match for each of T's
// methods along the way, or else V does not implement T.
// This lets us run the scan in overall linear time instead of
// the quadratic time a naive search would require.
// See also ../runtime/iface.go.
if V.Kind() == Interface {
v := (*interfaceType)(unsafe.Pointer(V))
i := 0
for j := 0; j < len(v.methods); j++ {
tm := &t.methods[i]
tmName := t.nameOff(tm.name)
vm := &v.methods[j]
vmName := V.nameOff(vm.name)
if vmName.name() == tmName.name() && V.typeOff(vm.typ) == t.typeOff(tm.typ) {
if !tmName.isExported() {
tmPkgPath := tmName.pkgPath()
if tmPkgPath == "" {
tmPkgPath = t.pkgPath.name()
}
vmPkgPath := vmName.pkgPath()
if vmPkgPath == "" {
vmPkgPath = v.pkgPath.name()
}
if tmPkgPath != vmPkgPath {
continue
}
}
if i++; i >= len(t.methods) {
return true
}
}
}
return false
}
v := V.uncommon()
if v == nil {
return false
}
i := 0
vmethods := v.methods()
for j := 0; j < int(v.mcount); j++ {
tm := &t.methods[i]
tmName := t.nameOff(tm.name)
vm := vmethods[j]
vmName := V.nameOff(vm.name)
if vmName.name() == tmName.name() && V.typeOff(vm.mtyp) == t.typeOff(tm.typ) {
if !tmName.isExported() {
tmPkgPath := tmName.pkgPath()
if tmPkgPath == "" {
tmPkgPath = t.pkgPath.name()
}
vmPkgPath := vmName.pkgPath()
if vmPkgPath == "" {
vmPkgPath = V.nameOff(v.pkgPath).name()
}
if tmPkgPath != vmPkgPath {
continue
}
}
if i++; i >= len(t.methods) {
return true
}
}
}
return false
}
// directlyAssignable reports whether a value x of type V can be directly
// assigned (using memmove) to a value of type T.
// https://golang.org/doc/go_spec.html#Assignability
// Ignoring the interface rules (implemented elsewhere)
// and the ideal constant rules (no ideal constants at run time).
func directlyAssignable(T, V *rtype) bool {
// x's type V is identical to T?
if T == V {
return true
}
// Otherwise at least one of T and V must not be defined
// and they must have the same kind.
if T.Name() != "" && V.Name() != "" || T.Kind() != V.Kind() {
return false
}
// x's type T and V must have identical underlying types.
return haveIdenticalUnderlyingType(T, V, true)
}
func haveIdenticalType(T, V Type, cmpTags bool) bool {
if cmpTags {
return T == V
}
if T.Name() != V.Name() || T.Kind() != V.Kind() {
return false
}
return haveIdenticalUnderlyingType(T.common(), V.common(), false)
}
func haveIdenticalUnderlyingType(T, V *rtype, cmpTags bool) bool {
if T == V {
return true
}
kind := T.Kind()
if kind != V.Kind() {
return false
}
// Non-composite types of equal kind have same underlying type
// (the predefined instance of the type).
if Bool <= kind && kind <= Complex128 || kind == String || kind == UnsafePointer {
return true
}
// Composite types.
switch kind {
case Array:
return T.Len() == V.Len() && haveIdenticalType(T.Elem(), V.Elem(), cmpTags)
case Chan:
// Special case:
// x is a bidirectional channel value, T is a channel type,
// and x's type V and T have identical element types.
if V.chanDir() == bothDir && haveIdenticalType(T.Elem(), V.Elem(), cmpTags) {
return true
}
// Otherwise continue test for identical underlying type.
return V.chanDir() == T.chanDir() && haveIdenticalType(T.Elem(), V.Elem(), cmpTags)
case Func:
t := (*funcType)(unsafe.Pointer(T))
v := (*funcType)(unsafe.Pointer(V))
if t.outCount != v.outCount || t.inCount != v.inCount {
return false
}
for i := 0; i < t.NumIn(); i++ {
if !haveIdenticalType(t.In(i), v.In(i), cmpTags) {
return false
}
}
for i := 0; i < t.NumOut(); i++ {
if !haveIdenticalType(t.Out(i), v.Out(i), cmpTags) {
return false
}
}
return true
case Interface:
t := (*interfaceType)(unsafe.Pointer(T))
v := (*interfaceType)(unsafe.Pointer(V))
if len(t.methods) == 0 && len(v.methods) == 0 {
return true
}
// Might have the same methods but still
// need a run time conversion.
return false
case Map:
return haveIdenticalType(T.Key(), V.Key(), cmpTags) && haveIdenticalType(T.Elem(), V.Elem(), cmpTags)
case Ptr, Slice:
return haveIdenticalType(T.Elem(), V.Elem(), cmpTags)
case Struct:
t := (*structType)(unsafe.Pointer(T))
v := (*structType)(unsafe.Pointer(V))
if len(t.fields) != len(v.fields) {
return false
}
if t.pkgPath.name() != v.pkgPath.name() {
return false
}
for i := range t.fields {
tf := &t.fields[i]
vf := &v.fields[i]
if tf.name.name() != vf.name.name() {
return false
}
if !haveIdenticalType(tf.typ, vf.typ, cmpTags) {
return false
}
if cmpTags && tf.name.tag() != vf.name.tag() {
return false
}
if tf.offsetEmbed != vf.offsetEmbed {
return false
}
}
return true
}
return false
}
type structTypeUncommon struct {
structType
u uncommonType
}
// toType converts from a *rtype to a Type that can be returned
// to the client of package reflect. In gc, the only concern is that
// a nil *rtype must be replaced by a nil Type, but in gccgo this
// function takes care of ensuring that multiple *rtype for the same
// type are coalesced into a single Type.
func toType(t *rtype) Type {
if t == nil {
return nil
}
return t
}
// ifaceIndir reports whether t is stored indirectly in an interface value.
func ifaceIndir(t *rtype) bool {
return t.kind&kindDirectIface == 0
}
src/internal/reflectlite/value.go 0 → 100644
View file @ 9650726e
// Copyright 2009 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.
package reflectlite
import (
"runtime"
"unsafe"
)
// Value is the reflection interface to a Go value.
//
// Not all methods apply to all kinds of values. Restrictions,
// if any, are noted in the documentation for each method.
// Use the Kind method to find out the kind of value before
// calling kind-specific methods. Calling a method
// inappropriate to the kind of type causes a run time panic.
//
// The zero Value represents no value.
// Its IsValid method returns false, its Kind method returns Invalid,
// its String method returns "<invalid Value>", and all other methods panic.
// Most functions and methods never return an invalid value.
// If one does, its documentation states the conditions explicitly.
//
// A Value can be used concurrently by multiple goroutines provided that
// the underlying Go value can be used concurrently for the equivalent
// direct operations.
//
// To compare two Values, compare the results of the Interface method.
// Using == on two Values does not compare the underlying values
// they represent.
type Value struct {
// typ holds the type of the value represented by a Value.
typ *rtype
// Pointer-valued data or, if flagIndir is set, pointer to data.
// Valid when either flagIndir is set or typ.pointers() is true.
ptr unsafe.Pointer
// flag holds metadata about the value.
// The lowest bits are flag bits:
// - flagStickyRO: obtained via unexported not embedded field, so read-only
// - flagEmbedRO: obtained via unexported embedded field, so read-only
// - flagIndir: val holds a pointer to the data
// - flagAddr: v.CanAddr is true (implies flagIndir)
// Value cannot represent method values.
// The next five bits give the Kind of the value.
// This repeats typ.Kind() except for method values.
// The remaining 23+ bits give a method number for method values.
// If flag.kind() != Func, code can assume that flagMethod is unset.
// If ifaceIndir(typ), code can assume that flagIndir is set.
flag
// A method value represents a curried method invocation
// like r.Read for some receiver r. The typ+val+flag bits describe
// the receiver r, but the flag's Kind bits say Func (methods are
// functions), and the top bits of the flag give the method number
// in r's type's method table.
}
type flag uintptr
const (
flagKindWidth = 5 // there are 27 kinds
flagKindMask flag = 1<<flagKindWidth - 1
flagStickyRO flag = 1 << 5
flagEmbedRO flag = 1 << 6
flagIndir flag = 1 << 7
flagAddr flag = 1 << 8
flagMethod flag = 1 << 9
flagMethodShift = 10
flagRO flag = flagStickyRO | flagEmbedRO
)
func (f flag) kind() Kind {
return Kind(f & flagKindMask)
}
func (f flag) ro() flag {
if f&flagRO != 0 {
return flagStickyRO
}
return 0
}
// packEface converts v to the empty interface.
func packEface(v Value) interface{} {
t := v.typ
var i interface{}
e := (*emptyInterface)(unsafe.Pointer(&i))
// First, fill in the data portion of the interface.
switch {
case ifaceIndir(t):
if v.flag&flagIndir == 0 {
panic("bad indir")
}
// Value is indirect, and so is the interface we're making.
ptr := v.ptr
if v.flag&flagAddr != 0 {
// TODO: pass safe boolean from valueInterface so
// we don't need to copy if safe==true?
c := unsafe_New(t)
typedmemmove(t, c, ptr)
ptr = c
}
e.word = ptr
case v.flag&flagIndir != 0:
// Value is indirect, but interface is direct. We need
// to load the data at v.ptr into the interface data word.
e.word = *(*unsafe.Pointer)(v.ptr)
default:
// Value is direct, and so is the interface.
e.word = v.ptr
}
// Now, fill in the type portion. We're very careful here not
// to have any operation between the e.word and e.typ assignments
// that would let the garbage collector observe the partially-built
// interface value.
e.typ = t
return i
}
// unpackEface converts the empty interface i to a Value.
func unpackEface(i interface{}) Value {
e := (*emptyInterface)(unsafe.Pointer(&i))
// NOTE: don't read e.word until we know whether it is really a pointer or not.
t := e.typ
if t == nil {
return Value{}
}
f := flag(t.Kind())
if ifaceIndir(t) {
f |= flagIndir
}
return Value{t, e.word, f}
}
// A ValueError occurs when a Value method is invoked on
// a Value that does not support it. Such cases are documented
// in the description of each method.
type ValueError struct {
Method string
Kind Kind
}
func (e *ValueError) Error() string {
return "reflect: call of " + e.Method + " on zero Value"
}
// methodName returns the name of the calling method,
// assumed to be two stack frames above.
func methodName() string {
pc, _, _, _ := runtime.Caller(2)
f := runtime.FuncForPC(pc)
if f == nil {
return "unknown method"
}
return f.Name()
}
// emptyInterface is the header for an interface{} value.
type emptyInterface struct {
typ *rtype
word unsafe.Pointer
}
// nonEmptyInterface is the header for an interface value with methods.
type nonEmptyInterface struct {
// see ../runtime/iface.go:/Itab
itab *struct {
ityp *rtype // static interface type
typ *rtype // dynamic concrete type
hash uint32 // copy of typ.hash
_ [4]byte
fun [100000]unsafe.Pointer // method table
}
word unsafe.Pointer
}
// mustBeExported panics if f records that the value was obtained using
// an unexported field.
func (f flag) mustBeExported() {
if f == 0 {
panic(&ValueError{methodName(), 0})
}
if f&flagRO != 0 {
panic("reflect: " + methodName() + " using value obtained using unexported field")
}
}
// mustBeAssignable panics if f records that the value is not assignable,
// which is to say that either it was obtained using an unexported field
// or it is not addressable.
func (f flag) mustBeAssignable() {
if f == 0 {
panic(&ValueError{methodName(), Invalid})
}
// Assignable if addressable and not read-only.
if f&flagRO != 0 {
panic("reflect: " + methodName() + " using value obtained using unexported field")
}
if f&flagAddr == 0 {
panic("reflect: " + methodName() + " using unaddressable value")
}
}
// CanSet reports whether the value of v can be changed.
// A Value can be changed only if it is addressable and was not
// obtained by the use of unexported struct fields.
// If CanSet returns false, calling Set or any type-specific
// setter (e.g., SetBool, SetInt) will panic.
func (v Value) CanSet() bool {
return v.flag&(flagAddr|flagRO) == flagAddr
}
// Elem returns the value that the interface v contains
// or that the pointer v points to.
// It panics if v's Kind is not Interface or Ptr.
// It returns the zero Value if v is nil.
func (v Value) Elem() Value {
k := v.kind()
switch k {
case Interface:
var eface interface{}
if v.typ.NumMethod() == 0 {
eface = *(*interface{})(v.ptr)
} else {
eface = (interface{})(*(*interface {
M()
})(v.ptr))
}
x := unpackEface(eface)
if x.flag != 0 {
x.flag |= v.flag.ro()
}
return x
case Ptr:
ptr := v.ptr
if v.flag&flagIndir != 0 {
ptr = *(*unsafe.Pointer)(ptr)
}
// The returned value's address is v's value.
if ptr == nil {
return Value{}
}
tt := (*ptrType)(unsafe.Pointer(v.typ))
typ := tt.elem
fl := v.flag&flagRO | flagIndir | flagAddr
fl |= flag(typ.Kind())
return Value{typ, ptr, fl}
}
panic(&ValueError{"reflectlite.Value.Elem", v.kind()})
}
func valueInterface(v Value) interface{} {
if v.flag == 0 {
panic(&ValueError{"reflectlite.Value.Interface", 0})
}
if v.kind() == Interface {
// Special case: return the element inside the interface.
// Empty interface has one layout, all interfaces with
// methods have a second layout.
if v.numMethod() == 0 {
return *(*interface{})(v.ptr)
}
return *(*interface {
M()
})(v.ptr)
}
// TODO: pass safe to packEface so we don't need to copy if safe==true?
return packEface(v)
}
// IsNil reports whether its argument v is nil. The argument must be
// a chan, func, interface, map, pointer, or slice value; if it is
// not, IsNil panics. Note that IsNil is not always equivalent to a
// regular comparison with nil in Go. For example, if v was created
// by calling ValueOf with an uninitialized interface variable i,
// i==nil will be true but v.IsNil will panic as v will be the zero
// Value.
func (v Value) IsNil() bool {
k := v.kind()
switch k {
case Chan, Func, Map, Ptr, UnsafePointer:
// if v.flag&flagMethod != 0 {
// return false
// }
ptr := v.ptr
if v.flag&flagIndir != 0 {
ptr = *(*unsafe.Pointer)(ptr)
}
return ptr == nil
case Interface, Slice:
// Both interface and slice are nil if first word is 0.
// Both are always bigger than a word; assume flagIndir.
return *(*unsafe.Pointer)(v.ptr) == nil
}
panic(&ValueError{"reflectlite.Value.IsNil", v.kind()})
}
// IsValid reports whether v represents a value.
// It returns false if v is the zero Value.
// If IsValid returns false, all other methods except String panic.
// Most functions and methods never return an invalid value.
// If one does, its documentation states the conditions explicitly.
func (v Value) IsValid() bool {
return v.flag != 0
}
// Kind returns v's Kind.
// If v is the zero Value (IsValid returns false), Kind returns Invalid.
func (v Value) Kind() Kind {
return v.kind()
}
// NumMethod returns the number of exported methods in the value's method set.
func (v Value) numMethod() int {
if v.typ == nil {
panic(&ValueError{"reflectlite.Value.NumMethod", Invalid})
}
return v.typ.NumMethod()
}
// Set assigns x to the value v.
// It panics if CanSet returns false.
// As in Go, x's value must be assignable to v's type.
func (v Value) Set(x Value) {
v.mustBeAssignable()
x.mustBeExported() // do not let unexported x leak
var target unsafe.Pointer
if v.kind() == Interface {
target = v.ptr
}
x = x.assignTo("reflectlite.Set", v.typ, target)
if x.flag&flagIndir != 0 {
typedmemmove(v.typ, v.ptr, x.ptr)
} else {
*(*unsafe.Pointer)(v.ptr) = x.ptr
}
}
// Type returns v's type.
func (v Value) Type() Type {
f := v.flag
if f == 0 {
panic(&ValueError{"reflectlite.Value.Type", Invalid})
}
// Method values not supported.
return v.typ
}
// stringHeader is a safe version of StringHeader used within this package.
type stringHeader struct {
Data unsafe.Pointer
Len int
}
// sliceHeader is a safe version of SliceHeader used within this package.
type sliceHeader struct {
Data unsafe.Pointer
Len int
Cap int
}
/*
* constructors
*/
// implemented in package runtime
func unsafe_New(*rtype) unsafe.Pointer
// ValueOf returns a new Value initialized to the concrete value
// stored in the interface i. ValueOf(nil) returns the zero Value.
func ValueOf(i interface{}) Value {
if i == nil {
return Value{}
}
// TODO: Maybe allow contents of a Value to live on the stack.
// For now we make the contents always escape to the heap. It
// makes life easier in a few places (see chanrecv/mapassign
// comment below).
escapes(i)
return unpackEface(i)
}
// assignTo returns a value v that can be assigned directly to typ.
// It panics if v is not assignable to typ.
// For a conversion to an interface type, target is a suggested scratch space to use.
func (v Value) assignTo(context string, dst *rtype, target unsafe.Pointer) Value {
// if v.flag&flagMethod != 0 {
// v = makeMethodValue(context, v)
// }
switch {
case directlyAssignable(dst, v.typ):
// Overwrite type so that they match.
// Same memory layout, so no harm done.
fl := v.flag&(flagAddr|flagIndir) | v.flag.ro()
fl |= flag(dst.Kind())
return Value{dst, v.ptr, fl}
case implements(dst, v.typ):
if target == nil {
target = unsafe_New(dst)
}
if v.Kind() == Interface && v.IsNil() {
// A nil ReadWriter passed to nil Reader is OK,
// but using ifaceE2I below will panic.
// Avoid the panic by returning a nil dst (e.g., Reader) explicitly.
return Value{dst, nil, flag(Interface)}
}
x := valueInterface(v)
if dst.NumMethod() == 0 {
*(*interface{})(target) = x
} else {
ifaceE2I(dst, x, target)
}
return Value{dst, target, flagIndir | flag(Interface)}
}
// Failed.
panic(context + ": value of type " + v.typ.String() + " is not assignable to type " + dst.String())
}
func ifaceE2I(t *rtype, src interface{}, dst unsafe.Pointer)
// typedmemmove copies a value of type t to dst from src.
//go:noescape
func typedmemmove(t *rtype, dst, src unsafe.Pointer)
// Dummy annotation marking that the value x escapes,
// for use in cases where the reflect code is so clever that
// the compiler cannot follow.
func escapes(x interface{}) {
if dummy.b {
dummy.x = x
}
}
var dummy struct {
b bool
x interface{}
}
src/runtime/iface.go
View file @ 9650726e
......@@ -492,6 +492,11 @@ func reflect_ifaceE2I(inter *interfacetype, e eface, dst *iface) {
*dst = assertE2I(inter, e)
}
//go:linkname reflectlite_ifaceE2I internal/reflectlite.ifaceE2I
func reflectlite_ifaceE2I(inter *interfacetype, e eface, dst *iface) {
*dst = assertE2I(inter, e)
}
func iterate_itabs(fn func(*itab)) {
// Note: only runs during stop the world or with itabLock held,
// so no other locks/atomics needed.
......
src/runtime/malloc.go
View file @ 9650726e
......@@ -1073,6 +1073,11 @@ func reflect_unsafe_New(typ *_type) unsafe.Pointer {
return mallocgc(typ.size, typ, true)
}
//go:linkname reflectlite_unsafe_New internal/reflectlite.unsafe_New
func reflectlite_unsafe_New(typ *_type) unsafe.Pointer {
return mallocgc(typ.size, typ, true)
}
// newarray allocates an array of n elements of type typ.
func newarray(typ *_type, n int) unsafe.Pointer {
if n == 1 {
......
src/runtime/mbarrier.go
View file @ 9650726e
......@@ -186,6 +186,11 @@ func reflect_typedmemmove(typ *_type, dst, src unsafe.Pointer) {
typedmemmove(typ, dst, src)
}
//go:linkname reflectlite_typedmemmove internal/reflectlite.typedmemmove
func reflectlite_typedmemmove(typ *_type, dst, src unsafe.Pointer) {
reflect_typedmemmove(typ, dst, src)
}
// typedmemmovepartial is like typedmemmove but assumes that
// dst and src point off bytes into the value and only copies size bytes.
//go:linkname reflect_typedmemmovepartial reflect.typedmemmovepartial
......
src/runtime/runtime1.go
View file @ 9650726e
......@@ -490,6 +490,18 @@ func reflect_resolveTextOff(rtype unsafe.Pointer, off int32) unsafe.Pointer {
}
// reflectlite_resolveNameOff resolves a name offset from a base pointer.
//go:linkname reflectlite_resolveNameOff internal/reflectlite.resolveNameOff
func reflectlite_resolveNameOff(ptrInModule unsafe.Pointer, off int32) unsafe.Pointer {
return unsafe.Pointer(resolveNameOff(ptrInModule, nameOff(off)).bytes)
}
// reflectlite_resolveTypeOff resolves an *rtype offset from a base type.
//go:linkname reflectlite_resolveTypeOff internal/reflectlite.resolveTypeOff
func reflectlite_resolveTypeOff(rtype unsafe.Pointer, off int32) unsafe.Pointer {
return unsafe.Pointer((*_type)(rtype).typeOff(typeOff(off)))
}
// reflect_addReflectOff adds a pointer to the reflection offset lookup map.
//go:linkname reflect_addReflectOff reflect.addReflectOff
func reflect_addReflectOff(ptr unsafe.Pointer) int32 {
......
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