issue15528.go

     1  // run
     2  
     3  // Copyright 2016 The Go Authors. All rights reserved.
     4  // Use of this source code is governed by a BSD-style
     5  // license that can be found in the LICENSE file.
     6  
     7  package main
     8  
     9  import (
    10  	"fmt"
    11  	"io"
    12  	"os"
    13  	"reflect"
    14  	"unsafe"
    15  )
    16  
    17  type RWS struct{}
    18  
    19  func (x *RWS) Read(p []byte) (n int, err error)                   { return }
    20  func (x *RWS) Write(p []byte) (n int, err error)                  { return }
    21  func (x *RWS) Seek(offset int64, whence int) (n int64, err error) { return }
    22  func (x *RWS) String() string                                     { return "rws" }
    23  
    24  func makeRWS() io.ReadWriteSeeker { return &RWS{} }
    25  func makeStringer() fmt.Stringer  { return &RWS{} }
    26  
    27  // Test correct construction of static empty interface values
    28  var efaces = [...]struct {
    29  	x interface{}
    30  	s string
    31  }{
    32  	{nil, "<nil> <nil>"},
    33  	{1, "int 1"},
    34  	{int(1), "int 1"},
    35  	{Int(int(2)), "main.Int Int=2"},
    36  	{int(Int(3)), "int 3"},
    37  	{[1]int{2}, "[1]int [2]"},
    38  	{io.Reader(io.ReadWriter(io.ReadWriteSeeker(nil))), "<nil> <nil>"},
    39  	{io.Reader(io.ReadWriter(io.ReadWriteSeeker(&RWS{}))), "*main.RWS rws"},
    40  	{makeRWS(), "*main.RWS rws"},
    41  	{map[string]string{"here": "there"}, "map[string]string map[here:there]"},
    42  	{chan bool(nil), "chan bool <nil>"},
    43  	{unsafe.Pointer(uintptr(0)), "unsafe.Pointer <nil>"},
    44  	{(*byte)(nil), "*uint8 <nil>"},
    45  	{io.Writer((*os.File)(nil)), "*os.File <nil>"},
    46  	{(interface{})(io.Writer((*os.File)(nil))), "*os.File <nil>"},
    47  	{fmt.Stringer(Strunger(((*Int)(nil)))), "*main.Int <nil>"},
    48  }
    49  
    50  type Int int
    51  
    52  func (i Int) String() string { return fmt.Sprintf("Int=%d", i) }
    53  func (i Int) Strung()        {}
    54  
    55  type Strunger interface {
    56  	fmt.Stringer
    57  	Strung()
    58  }
    59  
    60  // Test correct construction of static non-empty interface values
    61  var ifaces = [...]struct {
    62  	x fmt.Stringer
    63  	s string
    64  }{
    65  	{nil, "<nil> <nil> %!s(<nil>)"},
    66  	{Int(3), "main.Int 3 Int=3"},
    67  	{Int(int(Int(4))), "main.Int 4 Int=4"},
    68  	{Strunger(Int(5)), "main.Int 5 Int=5"},
    69  	{makeStringer(), "*main.RWS &main.RWS{} rws"},
    70  	{fmt.Stringer(nil), "<nil> <nil> %!s(<nil>)"},
    71  	{(*RWS)(nil), "*main.RWS (*main.RWS)(nil) rws"},
    72  }
    73  
    74  // Test correct handling of direct interface values
    75  var (
    76  	one  int         = 1
    77  	iptr interface{} = &one
    78  	clos int
    79  	f    interface{} = func() { clos++ }
    80  	deep interface{} = [1]struct{ a *[2]byte }{{a: &[2]byte{'z', 'w'}}}
    81  	ch   interface{} = make(chan bool, 1)
    82  )
    83  
    84  func main() {
    85  	var fail bool
    86  	for i, test := range efaces {
    87  		s := fmt.Sprintf("%[1]T %[1]v", test.x)
    88  		if s != test.s {
    89  			fmt.Printf("eface(%d)=%q want %q\n", i, s, test.s)
    90  			fail = true
    91  		}
    92  	}
    93  
    94  	for i, test := range ifaces {
    95  		s := fmt.Sprintf("%[1]T %#[1]v %[1]s", test.x)
    96  		if s != test.s {
    97  			fmt.Printf("iface(%d)=%q want %q\n", i, s, test.s)
    98  			fail = true
    99  		}
   100  	}
   101  
   102  	if got := *(iptr.(*int)); got != 1 {
   103  		fmt.Printf("bad int ptr %d\n", got)
   104  		fail = true
   105  	}
   106  
   107  	f.(func())()
   108  	f.(func())()
   109  	f.(func())()
   110  	if clos != 3 {
   111  		fmt.Printf("bad closure exec %d\n", clos)
   112  		fail = true
   113  	}
   114  
   115  	if !reflect.DeepEqual(*(deep.([1]struct{ a *[2]byte })[0].a), [2]byte{'z', 'w'}) {
   116  		fmt.Printf("bad deep directiface\n")
   117  		fail = true
   118  	}
   119  
   120  	cc := ch.(chan bool)
   121  	cc <- true
   122  	if got := <-cc; !got {
   123  		fmt.Printf("bad chan\n")
   124  		fail = true
   125  	}
   126  
   127  	if fail {
   128  		fmt.Println("BUG")
   129  		os.Exit(1)
   130  	}
   131  }
   132
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