]> Cypherpunks repositories - gostls13.git/commitdiff
reflect: add Type.ConvertibleTo, Value.Convert (API CHANGE)
authorRuss Cox <rsc@golang.org>
Sat, 22 Sep 2012 12:52:27 +0000 (08:52 -0400)
committerRuss Cox <rsc@golang.org>
Sat, 22 Sep 2012 12:52:27 +0000 (08:52 -0400)
Fixes #4047.

R=iant, r
CC=golang-dev
https://golang.org/cl/6500065

src/pkg/reflect/all_test.go
src/pkg/reflect/export_test.go [new file with mode: 0644]
src/pkg/reflect/type.go
src/pkg/reflect/value.go

index fe16087ea4648dfc13ec70621fdc8673be4f6b89..674285d9e0c6a0486357a198d2fea99524a8b8bf 100644 (file)
@@ -7,6 +7,7 @@ package reflect_test
 import (
        "bytes"
        "encoding/base64"
+       "flag"
        "fmt"
        "io"
        "math/rand"
@@ -1068,6 +1069,8 @@ type caseInfo struct {
        panic     bool
 }
 
+var allselect = flag.Bool("allselect", false, "exhaustive select test")
+
 func TestSelect(t *testing.T) {
        selectWatch.once.Do(func() { go selectWatcher() })
 
@@ -1091,6 +1094,9 @@ func TestSelect(t *testing.T) {
                if testing.Short() && n >= 1000 {
                        break
                }
+               if n >= 100000 && !*allselect {
+                       break
+               }
                if n%100000 == 0 && testing.Verbose() {
                        println("TestSelect", n)
                }
@@ -2162,6 +2168,447 @@ func TestAlias(t *testing.T) {
        }
 }
 
+var V = ValueOf
+
+func EmptyInterfaceV(x interface{}) Value {
+       return ValueOf(&x).Elem()
+}
+
+func ReaderV(x io.Reader) Value {
+       return ValueOf(&x).Elem()
+}
+
+func ReadWriterV(x io.ReadWriter) Value {
+       return ValueOf(&x).Elem()
+}
+
+type Empty struct{}
+type MyString string
+type MyBytes []byte
+type MyRunes []int32
+type MyFunc func()
+type MyByte byte
+
+var convertTests = []struct {
+       in  Value
+       out Value
+}{
+       // numbers
+       /*
+               Edit .+1,/\*\//-1>cat >/tmp/x.go && go run /tmp/x.go
+
+               package main
+
+               import "fmt"
+
+               var numbers = []string{
+                       "int8", "uint8", "int16", "uint16",
+                       "int32", "uint32", "int64", "uint64",
+                       "int", "uint", "uintptr",
+                       "float32", "float64",
+               }
+
+               func main() {
+                       // all pairs but in an unusual order,
+                       // to emit all the int8, uint8 cases
+                       // before n grows too big.
+                       n := 1
+                       for i, f := range numbers {
+                               for _, g := range numbers[i:] {
+                                       fmt.Printf("\t{V(%s(%d)), V(%s(%d))},\n", f, n, g, n)
+                                       n++
+                                       if f != g {
+                                               fmt.Printf("\t{V(%s(%d)), V(%s(%d))},\n", g, n, f, n)
+                                               n++
+                                       }
+                               }
+                       }
+               }
+       */
+       {V(int8(1)), V(int8(1))},
+       {V(int8(2)), V(uint8(2))},
+       {V(uint8(3)), V(int8(3))},
+       {V(int8(4)), V(int16(4))},
+       {V(int16(5)), V(int8(5))},
+       {V(int8(6)), V(uint16(6))},
+       {V(uint16(7)), V(int8(7))},
+       {V(int8(8)), V(int32(8))},
+       {V(int32(9)), V(int8(9))},
+       {V(int8(10)), V(uint32(10))},
+       {V(uint32(11)), V(int8(11))},
+       {V(int8(12)), V(int64(12))},
+       {V(int64(13)), V(int8(13))},
+       {V(int8(14)), V(uint64(14))},
+       {V(uint64(15)), V(int8(15))},
+       {V(int8(16)), V(int(16))},
+       {V(int(17)), V(int8(17))},
+       {V(int8(18)), V(uint(18))},
+       {V(uint(19)), V(int8(19))},
+       {V(int8(20)), V(uintptr(20))},
+       {V(uintptr(21)), V(int8(21))},
+       {V(int8(22)), V(float32(22))},
+       {V(float32(23)), V(int8(23))},
+       {V(int8(24)), V(float64(24))},
+       {V(float64(25)), V(int8(25))},
+       {V(uint8(26)), V(uint8(26))},
+       {V(uint8(27)), V(int16(27))},
+       {V(int16(28)), V(uint8(28))},
+       {V(uint8(29)), V(uint16(29))},
+       {V(uint16(30)), V(uint8(30))},
+       {V(uint8(31)), V(int32(31))},
+       {V(int32(32)), V(uint8(32))},
+       {V(uint8(33)), V(uint32(33))},
+       {V(uint32(34)), V(uint8(34))},
+       {V(uint8(35)), V(int64(35))},
+       {V(int64(36)), V(uint8(36))},
+       {V(uint8(37)), V(uint64(37))},
+       {V(uint64(38)), V(uint8(38))},
+       {V(uint8(39)), V(int(39))},
+       {V(int(40)), V(uint8(40))},
+       {V(uint8(41)), V(uint(41))},
+       {V(uint(42)), V(uint8(42))},
+       {V(uint8(43)), V(uintptr(43))},
+       {V(uintptr(44)), V(uint8(44))},
+       {V(uint8(45)), V(float32(45))},
+       {V(float32(46)), V(uint8(46))},
+       {V(uint8(47)), V(float64(47))},
+       {V(float64(48)), V(uint8(48))},
+       {V(int16(49)), V(int16(49))},
+       {V(int16(50)), V(uint16(50))},
+       {V(uint16(51)), V(int16(51))},
+       {V(int16(52)), V(int32(52))},
+       {V(int32(53)), V(int16(53))},
+       {V(int16(54)), V(uint32(54))},
+       {V(uint32(55)), V(int16(55))},
+       {V(int16(56)), V(int64(56))},
+       {V(int64(57)), V(int16(57))},
+       {V(int16(58)), V(uint64(58))},
+       {V(uint64(59)), V(int16(59))},
+       {V(int16(60)), V(int(60))},
+       {V(int(61)), V(int16(61))},
+       {V(int16(62)), V(uint(62))},
+       {V(uint(63)), V(int16(63))},
+       {V(int16(64)), V(uintptr(64))},
+       {V(uintptr(65)), V(int16(65))},
+       {V(int16(66)), V(float32(66))},
+       {V(float32(67)), V(int16(67))},
+       {V(int16(68)), V(float64(68))},
+       {V(float64(69)), V(int16(69))},
+       {V(uint16(70)), V(uint16(70))},
+       {V(uint16(71)), V(int32(71))},
+       {V(int32(72)), V(uint16(72))},
+       {V(uint16(73)), V(uint32(73))},
+       {V(uint32(74)), V(uint16(74))},
+       {V(uint16(75)), V(int64(75))},
+       {V(int64(76)), V(uint16(76))},
+       {V(uint16(77)), V(uint64(77))},
+       {V(uint64(78)), V(uint16(78))},
+       {V(uint16(79)), V(int(79))},
+       {V(int(80)), V(uint16(80))},
+       {V(uint16(81)), V(uint(81))},
+       {V(uint(82)), V(uint16(82))},
+       {V(uint16(83)), V(uintptr(83))},
+       {V(uintptr(84)), V(uint16(84))},
+       {V(uint16(85)), V(float32(85))},
+       {V(float32(86)), V(uint16(86))},
+       {V(uint16(87)), V(float64(87))},
+       {V(float64(88)), V(uint16(88))},
+       {V(int32(89)), V(int32(89))},
+       {V(int32(90)), V(uint32(90))},
+       {V(uint32(91)), V(int32(91))},
+       {V(int32(92)), V(int64(92))},
+       {V(int64(93)), V(int32(93))},
+       {V(int32(94)), V(uint64(94))},
+       {V(uint64(95)), V(int32(95))},
+       {V(int32(96)), V(int(96))},
+       {V(int(97)), V(int32(97))},
+       {V(int32(98)), V(uint(98))},
+       {V(uint(99)), V(int32(99))},
+       {V(int32(100)), V(uintptr(100))},
+       {V(uintptr(101)), V(int32(101))},
+       {V(int32(102)), V(float32(102))},
+       {V(float32(103)), V(int32(103))},
+       {V(int32(104)), V(float64(104))},
+       {V(float64(105)), V(int32(105))},
+       {V(uint32(106)), V(uint32(106))},
+       {V(uint32(107)), V(int64(107))},
+       {V(int64(108)), V(uint32(108))},
+       {V(uint32(109)), V(uint64(109))},
+       {V(uint64(110)), V(uint32(110))},
+       {V(uint32(111)), V(int(111))},
+       {V(int(112)), V(uint32(112))},
+       {V(uint32(113)), V(uint(113))},
+       {V(uint(114)), V(uint32(114))},
+       {V(uint32(115)), V(uintptr(115))},
+       {V(uintptr(116)), V(uint32(116))},
+       {V(uint32(117)), V(float32(117))},
+       {V(float32(118)), V(uint32(118))},
+       {V(uint32(119)), V(float64(119))},
+       {V(float64(120)), V(uint32(120))},
+       {V(int64(121)), V(int64(121))},
+       {V(int64(122)), V(uint64(122))},
+       {V(uint64(123)), V(int64(123))},
+       {V(int64(124)), V(int(124))},
+       {V(int(125)), V(int64(125))},
+       {V(int64(126)), V(uint(126))},
+       {V(uint(127)), V(int64(127))},
+       {V(int64(128)), V(uintptr(128))},
+       {V(uintptr(129)), V(int64(129))},
+       {V(int64(130)), V(float32(130))},
+       {V(float32(131)), V(int64(131))},
+       {V(int64(132)), V(float64(132))},
+       {V(float64(133)), V(int64(133))},
+       {V(uint64(134)), V(uint64(134))},
+       {V(uint64(135)), V(int(135))},
+       {V(int(136)), V(uint64(136))},
+       {V(uint64(137)), V(uint(137))},
+       {V(uint(138)), V(uint64(138))},
+       {V(uint64(139)), V(uintptr(139))},
+       {V(uintptr(140)), V(uint64(140))},
+       {V(uint64(141)), V(float32(141))},
+       {V(float32(142)), V(uint64(142))},
+       {V(uint64(143)), V(float64(143))},
+       {V(float64(144)), V(uint64(144))},
+       {V(int(145)), V(int(145))},
+       {V(int(146)), V(uint(146))},
+       {V(uint(147)), V(int(147))},
+       {V(int(148)), V(uintptr(148))},
+       {V(uintptr(149)), V(int(149))},
+       {V(int(150)), V(float32(150))},
+       {V(float32(151)), V(int(151))},
+       {V(int(152)), V(float64(152))},
+       {V(float64(153)), V(int(153))},
+       {V(uint(154)), V(uint(154))},
+       {V(uint(155)), V(uintptr(155))},
+       {V(uintptr(156)), V(uint(156))},
+       {V(uint(157)), V(float32(157))},
+       {V(float32(158)), V(uint(158))},
+       {V(uint(159)), V(float64(159))},
+       {V(float64(160)), V(uint(160))},
+       {V(uintptr(161)), V(uintptr(161))},
+       {V(uintptr(162)), V(float32(162))},
+       {V(float32(163)), V(uintptr(163))},
+       {V(uintptr(164)), V(float64(164))},
+       {V(float64(165)), V(uintptr(165))},
+       {V(float32(166)), V(float32(166))},
+       {V(float32(167)), V(float64(167))},
+       {V(float64(168)), V(float32(168))},
+       {V(float64(169)), V(float64(169))},
+
+       // truncation
+       {V(float64(1.5)), V(int(1))},
+
+       // complex
+       {V(complex64(1i)), V(complex64(1i))},
+       {V(complex64(2i)), V(complex128(2i))},
+       {V(complex128(3i)), V(complex64(3i))},
+       {V(complex128(4i)), V(complex128(4i))},
+
+       // string
+       {V(string("hello")), V(string("hello"))},
+       {V(string("bytes1")), V([]byte("bytes1"))},
+       {V([]byte("bytes2")), V(string("bytes2"))},
+       {V([]byte("bytes3")), V([]byte("bytes3"))},
+       {V(string("runes♝")), V([]rune("runes♝"))},
+       {V([]rune("runes♕")), V(string("runes♕"))},
+       {V([]rune("runes🙈🙉🙊")), V([]rune("runes🙈🙉🙊"))},
+       {V(int('a')), V(string("a"))},
+       {V(int8('a')), V(string("a"))},
+       {V(int16('a')), V(string("a"))},
+       {V(int32('a')), V(string("a"))},
+       {V(int64('a')), V(string("a"))},
+       {V(uint('a')), V(string("a"))},
+       {V(uint8('a')), V(string("a"))},
+       {V(uint16('a')), V(string("a"))},
+       {V(uint32('a')), V(string("a"))},
+       {V(uint64('a')), V(string("a"))},
+       {V(uintptr('a')), V(string("a"))},
+       {V(int(-1)), V(string("\uFFFD"))},
+       {V(int8(-2)), V(string("\uFFFD"))},
+       {V(int16(-3)), V(string("\uFFFD"))},
+       {V(int32(-4)), V(string("\uFFFD"))},
+       {V(int64(-5)), V(string("\uFFFD"))},
+       {V(uint(0x110001)), V(string("\uFFFD"))},
+       {V(uint32(0x110002)), V(string("\uFFFD"))},
+       {V(uint64(0x110003)), V(string("\uFFFD"))},
+       {V(uintptr(0x110004)), V(string("\uFFFD"))},
+
+       // named string
+       {V(MyString("hello")), V(string("hello"))},
+       {V(string("hello")), V(MyString("hello"))},
+       {V(string("hello")), V(string("hello"))},
+       {V(MyString("hello")), V(MyString("hello"))},
+       {V(MyString("bytes1")), V([]byte("bytes1"))},
+       {V([]byte("bytes2")), V(MyString("bytes2"))},
+       {V([]byte("bytes3")), V([]byte("bytes3"))},
+       {V(MyString("runes♝")), V([]rune("runes♝"))},
+       {V([]rune("runes♕")), V(MyString("runes♕"))},
+       {V([]rune("runes🙈🙉🙊")), V([]rune("runes🙈🙉🙊"))},
+       {V([]rune("runes🙈🙉🙊")), V(MyRunes("runes🙈🙉🙊"))},
+       {V(MyRunes("runes🙈🙉🙊")), V([]rune("runes🙈🙉🙊"))},
+       {V(int('a')), V(MyString("a"))},
+       {V(int8('a')), V(MyString("a"))},
+       {V(int16('a')), V(MyString("a"))},
+       {V(int32('a')), V(MyString("a"))},
+       {V(int64('a')), V(MyString("a"))},
+       {V(uint('a')), V(MyString("a"))},
+       {V(uint8('a')), V(MyString("a"))},
+       {V(uint16('a')), V(MyString("a"))},
+       {V(uint32('a')), V(MyString("a"))},
+       {V(uint64('a')), V(MyString("a"))},
+       {V(uintptr('a')), V(MyString("a"))},
+       {V(int(-1)), V(MyString("\uFFFD"))},
+       {V(int8(-2)), V(MyString("\uFFFD"))},
+       {V(int16(-3)), V(MyString("\uFFFD"))},
+       {V(int32(-4)), V(MyString("\uFFFD"))},
+       {V(int64(-5)), V(MyString("\uFFFD"))},
+       {V(uint(0x110001)), V(MyString("\uFFFD"))},
+       {V(uint32(0x110002)), V(MyString("\uFFFD"))},
+       {V(uint64(0x110003)), V(MyString("\uFFFD"))},
+       {V(uintptr(0x110004)), V(MyString("\uFFFD"))},
+
+       // named []byte
+       {V(string("bytes1")), V(MyBytes("bytes1"))},
+       {V(MyBytes("bytes2")), V(string("bytes2"))},
+       {V(MyBytes("bytes3")), V(MyBytes("bytes3"))},
+       {V(MyString("bytes1")), V(MyBytes("bytes1"))},
+       {V(MyBytes("bytes2")), V(MyString("bytes2"))},
+
+       // named []rune
+       {V(string("runes♝")), V(MyRunes("runes♝"))},
+       {V(MyRunes("runes♕")), V(string("runes♕"))},
+       {V(MyRunes("runes🙈🙉🙊")), V(MyRunes("runes🙈🙉🙊"))},
+       {V(MyString("runes♝")), V(MyRunes("runes♝"))},
+       {V(MyRunes("runes♕")), V(MyString("runes♕"))},
+
+       // named types and equal underlying types
+       {V(new(int)), V(new(integer))},
+       {V(new(integer)), V(new(int))},
+       {V(Empty{}), V(struct{}{})},
+       {V(new(Empty)), V(new(struct{}))},
+       {V(struct{}{}), V(Empty{})},
+       {V(new(struct{})), V(new(Empty))},
+       {V(Empty{}), V(Empty{})},
+       {V(MyBytes{}), V([]byte{})},
+       {V([]byte{}), V(MyBytes{})},
+       {V((func())(nil)), V(MyFunc(nil))},
+       {V((MyFunc)(nil)), V((func())(nil))},
+
+       // can convert *byte and *MyByte
+       {V((*byte)(nil)), V((*MyByte)(nil))},
+       {V((*MyByte)(nil)), V((*byte)(nil))},
+
+       // cannot convert mismatched array sizes
+       {V([2]byte{}), V([2]byte{})},
+       {V([3]byte{}), V([3]byte{})},
+
+       // cannot convert other instances
+       {V((**byte)(nil)), V((**byte)(nil))},
+       {V((**MyByte)(nil)), V((**MyByte)(nil))},
+       {V((chan byte)(nil)), V((chan byte)(nil))},
+       {V((chan MyByte)(nil)), V((chan MyByte)(nil))},
+       {V(([]byte)(nil)), V(([]byte)(nil))},
+       {V(([]MyByte)(nil)), V(([]MyByte)(nil))},
+       {V((map[int]byte)(nil)), V((map[int]byte)(nil))},
+       {V((map[int]MyByte)(nil)), V((map[int]MyByte)(nil))},
+       {V((map[byte]int)(nil)), V((map[byte]int)(nil))},
+       {V((map[MyByte]int)(nil)), V((map[MyByte]int)(nil))},
+       {V([2]byte{}), V([2]byte{})},
+       {V([2]MyByte{}), V([2]MyByte{})},
+
+       // other
+       {V((***int)(nil)), V((***int)(nil))},
+       {V((***byte)(nil)), V((***byte)(nil))},
+       {V((***int32)(nil)), V((***int32)(nil))},
+       {V((***int64)(nil)), V((***int64)(nil))},
+       {V((chan int)(nil)), V((<-chan int)(nil))},
+       {V((chan int)(nil)), V((chan<- int)(nil))},
+       {V((chan string)(nil)), V((<-chan string)(nil))},
+       {V((chan string)(nil)), V((chan<- string)(nil))},
+       {V((chan byte)(nil)), V((chan byte)(nil))},
+       {V((chan MyByte)(nil)), V((chan MyByte)(nil))},
+       {V((map[int]bool)(nil)), V((map[int]bool)(nil))},
+       {V((map[int]byte)(nil)), V((map[int]byte)(nil))},
+       {V((map[uint]bool)(nil)), V((map[uint]bool)(nil))},
+       {V([]uint(nil)), V([]uint(nil))},
+       {V([]int(nil)), V([]int(nil))},
+       {V(new(interface{})), V(new(interface{}))},
+       {V(new(io.Reader)), V(new(io.Reader))},
+       {V(new(io.Writer)), V(new(io.Writer))},
+
+       // interfaces
+       {V(int(1)), EmptyInterfaceV(int(1))},
+       {V(string("hello")), EmptyInterfaceV(string("hello"))},
+       {V(new(bytes.Buffer)), ReaderV(new(bytes.Buffer))},
+       {ReadWriterV(new(bytes.Buffer)), ReaderV(new(bytes.Buffer))},
+       {V(new(bytes.Buffer)), ReadWriterV(new(bytes.Buffer))},
+}
+
+func TestConvert(t *testing.T) {
+       canConvert := map[[2]Type]bool{}
+       all := map[Type]bool{}
+
+       for _, tt := range convertTests {
+               t1 := tt.in.Type()
+               if !t1.ConvertibleTo(t1) {
+                       t.Errorf("(%s).ConvertibleTo(%s) = false, want true", t1, t1)
+                       continue
+               }
+
+               t2 := tt.out.Type()
+               if !t1.ConvertibleTo(t2) {
+                       t.Errorf("(%s).ConvertibleTo(%s) = false, want true", t1, t2)
+                       continue
+               }
+
+               all[t1] = true
+               all[t2] = true
+               canConvert[[2]Type{t1, t2}] = true
+
+               v1 := tt.in
+               vout1 := v1.Convert(t1)
+               out1 := vout1.Interface()
+               if vout1.Type() != tt.in.Type() || !DeepEqual(out1, tt.in.Interface()) {
+                       t.Errorf("ValueOf(%T(%v)).Convert(%s) = %T(%v), want %T(%v)", tt.in.Interface(), tt.in.Interface(), t1, out1, out1, tt.in.Interface(), tt.in.Interface())
+               }
+
+               vout := v1.Convert(t2)
+               out := vout.Interface()
+               if vout.Type() != tt.out.Type() || !DeepEqual(out, tt.out.Interface()) {
+                       t.Errorf("ValueOf(%T(%v)).Convert(%s) = %T(%v), want %T(%v)", tt.in.Interface(), tt.in.Interface(), t2, out, out, tt.out.Interface(), tt.out.Interface())
+               }
+
+               if IsRO(v1) {
+                       t.Errorf("table entry %v is RO, should not be", v1)
+               }
+               if IsRO(vout1) {
+                       t.Errorf("self-conversion output %v is RO, should not be", vout1)
+               }
+               if IsRO(vout) {
+                       t.Errorf("conversion output %v is RO, should not be", vout)
+               }
+               if !IsRO(MakeRO(v1).Convert(t1)) {
+                       t.Errorf("RO self-conversion output %v is not RO, should be", v1)
+               }
+               if !IsRO(MakeRO(v1).Convert(t2)) {
+                       t.Errorf("RO conversion output %v is not RO, should be", v1)
+               }
+       }
+
+       // Assume that of all the types we saw during the tests,
+       // if there wasn't an explicit entry for a conversion between
+       // a pair of types, then it's not to be allowed. This checks for
+       // things like 'int64' converting to '*int'.
+       for t1 := range all {
+               for t2 := range all {
+                       expectOK := t1 == t2 || canConvert[[2]Type{t1, t2}] || t2.Kind() == Interface && t2.NumMethod() == 0
+                       if ok := t1.ConvertibleTo(t2); ok != expectOK {
+                               t.Errorf("(%s).ConvertibleTo(%s) = %v, want %v", t1, t2, ok, expectOK)
+                       }
+               }
+       }
+}
+
 type B1 struct {
        X int
        Y int
diff --git a/src/pkg/reflect/export_test.go b/src/pkg/reflect/export_test.go
new file mode 100644 (file)
index 0000000..6e0d8a3
--- /dev/null
@@ -0,0 +1,16 @@
+// Copyright 2012 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 reflect
+
+// MakeRO returns a copy of v with the read-only flag set.
+func MakeRO(v Value) Value {
+       v.flag |= flagRO
+       return v
+}
+
+// IsRO reports whether v's read-only flag is set.
+func IsRO(v Value) bool {
+       return v.flag&flagRO != 0
+}
index dfbd859a7ae80cda62de475f83399510efbc0ff0..4878f2dc28e543922a2c809fb1912f265bc3de11 100644 (file)
@@ -92,6 +92,9 @@ type Type interface {
        // AssignableTo returns true if a value of the type is assignable to type u.
        AssignableTo(u Type) bool
 
+       // ConvertibleTo returns true if a value of the type is convertible to type u.
+       ConvertibleTo(u Type) bool
+
        // Methods applicable only to some types, depending on Kind.
        // The methods allowed for each kind are:
        //
@@ -1096,6 +1099,14 @@ func (t *commonType) AssignableTo(u Type) bool {
        return directlyAssignable(uu, t) || implements(uu, t)
 }
 
+func (t *commonType) ConvertibleTo(u Type) bool {
+       if u == nil {
+               panic("reflect: nil type passed to Type.AssignableTo")
+       }
+       uu := u.(*commonType)
+       return convertOp(uu, t) != nil
+}
+
 // implements returns true if the type V implements the interface type T.
 func implements(T, V *commonType) bool {
        if T.Kind() != Interface {
@@ -1167,10 +1178,28 @@ func directlyAssignable(T, V *commonType) bool {
                return false
        }
 
-       // x's type T and V have identical underlying types.
-       // Since at least one is unnamed, only the composite types
-       // need to be considered.
-       switch T.Kind() {
+       // x's type T and V must  have identical underlying types.
+       return haveIdenticalUnderlyingType(T, V)
+}
+
+func haveIdenticalUnderlyingType(T, V *commonType) 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.Elem() == V.Elem() && T.Len() == V.Len()
 
index 1c3dc9ae9a8adde13e2c669dadcc763edabff588..4d5e38677699fcb02209fa107abefaa47d7cb8d5 100644 (file)
@@ -302,6 +302,17 @@ func (v Value) Bytes() []byte {
        return *(*[]byte)(v.val)
 }
 
+// runes returns v's underlying value.
+// It panics if v's underlying value is not a slice of runes (int32s).
+func (v Value) runes() []rune {
+       v.mustBe(Slice)
+       if v.typ.Elem().Kind() != Int32 {
+               panic("reflect.Value.Bytes of non-rune slice")
+       }
+       // Slice is always bigger than a word; assume flagIndir.
+       return *(*[]rune)(v.val)
+}
+
 // CanAddr returns true if the value's address can be obtained with Addr.
 // Such values are called addressable.  A value is addressable if it is
 // an element of a slice, an element of an addressable array,
@@ -1221,6 +1232,17 @@ func (v Value) SetBytes(x []byte) {
        *(*[]byte)(v.val) = x
 }
 
+// setRunes sets v's underlying value.
+// It panics if v's underlying value is not a slice of runes (int32s).
+func (v Value) setRunes(x []rune) {
+       v.mustBeAssignable()
+       v.mustBe(Slice)
+       if v.typ.Elem().Kind() != Int32 {
+               panic("reflect.Value.setRunes of non-rune slice")
+       }
+       *(*[]rune)(v.val) = x
+}
+
 // SetComplex sets v's underlying value to x.
 // It panics if v's Kind is not Complex64 or Complex128, or if CanSet() is false.
 func (v Value) SetComplex(x complex128) {
@@ -1916,6 +1938,302 @@ func (v Value) assignTo(context string, dst *commonType, target *interface{}) Va
        panic(context + ": value of type " + v.typ.String() + " is not assignable to type " + dst.String())
 }
 
+// Convert returns the value v converted to type t.
+// If the usual Go conversion rules do not allow conversion
+// of the value v to type t, Convert panics.
+func (v Value) Convert(t Type) Value {
+       if v.flag&flagMethod != 0 {
+               panic("reflect.Value.Convert: cannot convert method values")
+       }
+       op := convertOp(t.common(), v.typ)
+       if op == nil {
+               panic("reflect.Value.Convert: value of type " + v.typ.String() + " cannot be converted to type " + t.String())
+       }
+       return op(v, t)
+}
+
+// convertOp returns the function to convert a value of type src
+// to a value of type dst. If the conversion is illegal, convertOp returns nil.
+func convertOp(dst, src *commonType) func(Value, Type) Value {
+       switch src.Kind() {
+       case Int, Int8, Int16, Int32, Int64:
+               switch dst.Kind() {
+               case Int, Int8, Int16, Int32, Int64, Uint, Uint8, Uint16, Uint32, Uint64, Uintptr:
+                       return cvtInt
+               case Float32, Float64:
+                       return cvtIntFloat
+               case String:
+                       return cvtIntString
+               }
+
+       case Uint, Uint8, Uint16, Uint32, Uint64, Uintptr:
+               switch dst.Kind() {
+               case Int, Int8, Int16, Int32, Int64, Uint, Uint8, Uint16, Uint32, Uint64, Uintptr:
+                       return cvtUint
+               case Float32, Float64:
+                       return cvtUintFloat
+               case String:
+                       return cvtUintString
+               }
+
+       case Float32, Float64:
+               switch dst.Kind() {
+               case Int, Int8, Int16, Int32, Int64:
+                       return cvtFloatInt
+               case Uint, Uint8, Uint16, Uint32, Uint64, Uintptr:
+                       return cvtFloatUint
+               case Float32, Float64:
+                       return cvtFloat
+               }
+
+       case Complex64, Complex128:
+               switch dst.Kind() {
+               case Complex64, Complex128:
+                       return cvtComplex
+               }
+
+       case String:
+               if dst.Kind() == Slice && dst.Elem().PkgPath() == "" {
+                       switch dst.Elem().Kind() {
+                       case Uint8:
+                               return cvtStringBytes
+                       case Int32:
+                               return cvtStringRunes
+                       }
+               }
+
+       case Slice:
+               if dst.Kind() == String && src.Elem().PkgPath() == "" {
+                       switch src.Elem().Kind() {
+                       case Uint8:
+                               return cvtBytesString
+                       case Int32:
+                               return cvtRunesString
+                       }
+               }
+       }
+
+       // dst and src have same underlying type.
+       if haveIdenticalUnderlyingType(dst, src) {
+               return cvtDirect
+       }
+
+       // dst and src are unnamed pointer types with same underlying base type.
+       if dst.Kind() == Ptr && dst.Name() == "" &&
+               src.Kind() == Ptr && src.Name() == "" &&
+               haveIdenticalUnderlyingType(dst.Elem().common(), src.Elem().common()) {
+               return cvtDirect
+       }
+
+       if implements(dst, src) {
+               if src.Kind() == Interface {
+                       return cvtI2I
+               }
+               return cvtT2I
+       }
+
+       return nil
+}
+
+// makeInt returns a Value of type t equal to bits (possibly truncated),
+// where t is a signed or unsigned int type.
+func makeInt(f flag, bits uint64, t Type) Value {
+       typ := t.common()
+       if typ.size > ptrSize {
+               // Assume ptrSize >= 4, so this must be uint64.
+               ptr := unsafe_New(t)
+               *(*uint64)(unsafe.Pointer(ptr)) = bits
+               return Value{typ, ptr, f | flag(typ.Kind())<<flagKindShift}
+       }
+       var w iword
+       switch typ.size {
+       case 1:
+               *(*uint8)(unsafe.Pointer(&w)) = uint8(bits)
+       case 2:
+               *(*uint16)(unsafe.Pointer(&w)) = uint16(bits)
+       case 4:
+               *(*uint32)(unsafe.Pointer(&w)) = uint32(bits)
+       case 8:
+               *(*uint64)(unsafe.Pointer(&w)) = uint64(bits)
+       }
+       return Value{typ, unsafe.Pointer(w), f | flag(typ.Kind())<<flagKindShift}
+}
+
+// makeFloat returns a Value of type t equal to v (possibly truncated to float32),
+// where t is a float32 or float64 type.
+func makeFloat(f flag, v float64, t Type) Value {
+       typ := t.common()
+       if typ.size > ptrSize {
+               // Assume ptrSize >= 4, so this must be float64.
+               ptr := unsafe_New(t)
+               *(*float64)(unsafe.Pointer(ptr)) = v
+               return Value{typ, ptr, f | flag(typ.Kind())<<flagKindShift}
+       }
+
+       var w iword
+       switch typ.size {
+       case 4:
+               *(*float32)(unsafe.Pointer(&w)) = float32(v)
+       case 8:
+               *(*float64)(unsafe.Pointer(&w)) = v
+       }
+       return Value{typ, unsafe.Pointer(w), f | flag(typ.Kind())<<flagKindShift}
+}
+
+// makeComplex returns a Value of type t equal to v (possibly truncated to complex64),
+// where t is a complex64 or complex128 type.
+func makeComplex(f flag, v complex128, t Type) Value {
+       typ := t.common()
+       if typ.size > ptrSize {
+               ptr := unsafe_New(t)
+               switch typ.size {
+               case 8:
+                       *(*complex64)(unsafe.Pointer(ptr)) = complex64(v)
+               case 16:
+                       *(*complex128)(unsafe.Pointer(ptr)) = v
+               }
+               return Value{typ, ptr, f | flag(typ.Kind())<<flagKindShift}
+       }
+
+       // Assume ptrSize <= 8 so this must be complex64.
+       var w iword
+       *(*complex64)(unsafe.Pointer(&w)) = complex64(v)
+       return Value{typ, unsafe.Pointer(w), f | flag(typ.Kind())<<flagKindShift}
+}
+
+func makeString(f flag, v string, t Type) Value {
+       ret := New(t).Elem()
+       ret.SetString(v)
+       ret.flag = ret.flag&^flagAddr | f
+       return ret
+}
+
+func makeBytes(f flag, v []byte, t Type) Value {
+       ret := New(t).Elem()
+       ret.SetBytes(v)
+       ret.flag = ret.flag&^flagAddr | f
+       return ret
+}
+
+func makeRunes(f flag, v []rune, t Type) Value {
+       ret := New(t).Elem()
+       ret.setRunes(v)
+       ret.flag = ret.flag&^flagAddr | f
+       return ret
+}
+
+// These conversion functions are returned by convertOp
+// for classes of conversions. For example, the first function, cvtInt,
+// takes any value v of signed int type and returns the value converted
+// to type t, where t is any signed or unsigned int type.
+
+// convertOp: intXX -> [u]intXX
+func cvtInt(v Value, t Type) Value {
+       return makeInt(v.flag&flagRO, uint64(v.Int()), t)
+}
+
+// convertOp: uintXX -> [u]intXX
+func cvtUint(v Value, t Type) Value {
+       return makeInt(v.flag&flagRO, v.Uint(), t)
+}
+
+// convertOp: floatXX -> intXX
+func cvtFloatInt(v Value, t Type) Value {
+       return makeInt(v.flag&flagRO, uint64(int64(v.Float())), t)
+}
+
+// convertOp: floatXX -> uintXX
+func cvtFloatUint(v Value, t Type) Value {
+       return makeInt(v.flag&flagRO, uint64(v.Float()), t)
+}
+
+// convertOp: intXX -> floatXX
+func cvtIntFloat(v Value, t Type) Value {
+       return makeFloat(v.flag&flagRO, float64(v.Int()), t)
+}
+
+// convertOp: uintXX -> floatXX
+func cvtUintFloat(v Value, t Type) Value {
+       return makeFloat(v.flag&flagRO, float64(v.Uint()), t)
+}
+
+// convertOp: floatXX -> floatXX
+func cvtFloat(v Value, t Type) Value {
+       return makeFloat(v.flag&flagRO, v.Float(), t)
+}
+
+// convertOp: complexXX -> complexXX
+func cvtComplex(v Value, t Type) Value {
+       return makeComplex(v.flag&flagRO, v.Complex(), t)
+}
+
+// convertOp: intXX -> string
+func cvtIntString(v Value, t Type) Value {
+       return makeString(v.flag&flagRO, string(v.Int()), t)
+}
+
+// convertOp: uintXX -> string
+func cvtUintString(v Value, t Type) Value {
+       return makeString(v.flag&flagRO, string(v.Uint()), t)
+}
+
+// convertOp: []byte -> string
+func cvtBytesString(v Value, t Type) Value {
+       return makeString(v.flag&flagRO, string(v.Bytes()), t)
+}
+
+// convertOp: string -> []byte
+func cvtStringBytes(v Value, t Type) Value {
+       return makeBytes(v.flag&flagRO, []byte(v.String()), t)
+}
+
+// convertOp: []rune -> string
+func cvtRunesString(v Value, t Type) Value {
+       return makeString(v.flag&flagRO, string(v.runes()), t)
+}
+
+// convertOp: string -> []rune
+func cvtStringRunes(v Value, t Type) Value {
+       return makeRunes(v.flag&flagRO, []rune(v.String()), t)
+}
+
+// convertOp: direct copy
+func cvtDirect(v Value, typ Type) Value {
+       f := v.flag
+       t := typ.common()
+       val := v.val
+       if f&flagAddr != 0 {
+               // indirect, mutable word - make a copy
+               ptr := unsafe_New(t)
+               memmove(ptr, val, t.size)
+               val = ptr
+               f &^= flagAddr
+       }
+       return Value{t, val, v.flag&flagRO | f}
+}
+
+// convertOp: concrete -> interface
+func cvtT2I(v Value, typ Type) Value {
+       target := new(interface{})
+       x := valueInterface(v, false)
+       if typ.NumMethod() == 0 {
+               *target = x
+       } else {
+               ifaceE2I(typ.runtimeType(), x, unsafe.Pointer(target))
+       }
+       return Value{typ.common(), unsafe.Pointer(target), v.flag&flagRO | flagIndir | flag(Interface)<<flagKindShift}
+}
+
+// convertOp: interface -> interface
+func cvtI2I(v Value, typ Type) Value {
+       if v.IsNil() {
+               ret := Zero(typ)
+               ret.flag |= v.flag & flagRO
+               return ret
+       }
+       return cvtT2I(v.Elem(), typ)
+}
+
 // implemented in ../pkg/runtime
 func chancap(ch iword) int32
 func chanclose(ch iword)