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[release-branch.r58] reflect: disallow Interface method on Value obtained via unexported name

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Also remove exp/datafmt that depends on the broken reflect behavior.

««« CL 5267049 / eeca0d4a91a3
reflect: disallow Interface method on Value obtained via unexported name

Had been allowing it for use by fmt, but it is too hard to lock down.
Fix other packages not to depend on it.

R=r, r
CC=golang-dev
https://golang.org/cl/5266054
»»»

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/5297042
This commit is contained in:
Andrew Gerrand 2011-10-18 14:06:11 +11:00
parent adfa87c5d7
commit 0584eb2e77
11 changed files with 285 additions and 1645 deletions
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1
src/pkg/Makefile
View File

@ -76,7 +76,6 @@ DIRS=\
encoding/hex\
encoding/pem\
exec\
exp/datafmt\
exp/eval\
exp/gui\
exp/gui/x11\

12
src/pkg/exp/datafmt/Makefile
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@ -1,12 +0,0 @@
# 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.
include ../../../Make.inc
TARG=exp/datafmt
GOFILES=\
datafmt.go\
parser.go\
include ../../../Make.pkg

731
src/pkg/exp/datafmt/datafmt.go
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@ -1,731 +0,0 @@
// 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 datafmt implements syntax-directed, type-driven formatting
of arbitrary data structures. Formatting a data structure consists of
two phases: first, a parser reads a format specification and builds a
"compiled" format. Then, the format can be applied repeatedly to
arbitrary values. Applying a format to a value evaluates to a []byte
containing the formatted value bytes, or nil.
A format specification is a set of package declarations and format rules:
Format = [ Entry { ";" Entry } [ ";" ] ] .
Entry = PackageDecl | FormatRule .
(The syntax of a format specification is presented in the same EBNF
notation as used in the Go language specification. The syntax of white
space, comments, identifiers, and string literals is the same as in Go.)
A package declaration binds a package name (such as 'ast') to a
package import path (such as '"go/ast"'). Each package used (in
a type name, see below) must be declared once before use.
PackageDecl = PackageName ImportPath .
PackageName = identifier .
ImportPath = string .
A format rule binds a rule name to a format expression. A rule name
may be a type name or one of the special names 'default' or '/'.
A type name may be the name of a predeclared type (for example, 'int',
'float32', etc.), the package-qualified name of a user-defined type
(for example, 'ast.MapType'), or an identifier indicating the structure
of unnamed composite types ('array', 'chan', 'func', 'interface', 'map',
or 'ptr'). Each rule must have a unique name; rules can be declared in
any order.
FormatRule = RuleName "=" Expression .
RuleName = TypeName | "default" | "/" .
TypeName = [ PackageName "." ] identifier .
To format a value, the value's type name is used to select the format rule
(there is an override mechanism, see below). The format expression of the
selected rule specifies how the value is formatted. Each format expression,
when applied to a value, evaluates to a byte sequence or nil.
In its most general form, a format expression is a list of alternatives,
each of which is a sequence of operands:
Expression = [ Sequence ] { "|" [ Sequence ] } .
Sequence = Operand { Operand } .
The formatted result produced by an expression is the result of the first
alternative sequence that evaluates to a non-nil result; if there is no
such alternative, the expression evaluates to nil. The result produced by
an operand sequence is the concatenation of the results of its operands.
If any operand in the sequence evaluates to nil, the entire sequence
evaluates to nil.
There are five kinds of operands:
Operand = Literal | Field | Group | Option | Repetition .
Literals evaluate to themselves, with two substitutions. First,
%-formats expand in the manner of fmt.Printf, with the current value
passed as the parameter. Second, the current indentation (see below)
is inserted after every newline or form feed character.
Literal = string .
This table shows string literals applied to the value 42 and the
corresponding formatted result:
"foo" foo
"%x" 2a
"x = %d" x = 42
"%#x = %d" 0x2a = 42
A field operand is a field name optionally followed by an alternate
rule name. The field name may be an identifier or one of the special
names @ or *.
Field = FieldName [ ":" RuleName ] .
FieldName = identifier | "@" | "*" .
If the field name is an identifier, the current value must be a struct,
and there must be a field with that name in the struct. The same lookup
rules apply as in the Go language (for instance, the name of an anonymous
field is the unqualified type name). The field name denotes the field
value in the struct. If the field is not found, formatting is aborted
and an error message is returned. (TODO consider changing the semantics
such that if a field is not found, it evaluates to nil).
The special name '@' denotes the current value.
The meaning of the special name '*' depends on the type of the current
value:
array, slice types array, slice element (inside {} only, see below)
interfaces value stored in interface
pointers value pointed to by pointer
(Implementation restriction: channel, function and map types are not
supported due to missing reflection support).
Fields are evaluated as follows: If the field value is nil, or an array
or slice element does not exist, the result is nil (see below for details
on array/slice elements). If the value is not nil the field value is
formatted (recursively) using the rule corresponding to its type name,
or the alternate rule name, if given.
The following example shows a complete format specification for a
struct 'myPackage.Point'. Assume the package
package myPackage // in directory myDir/myPackage
type Point struct {
name string;
x, y int;
}
Applying the format specification
myPackage "myDir/myPackage";
int = "%d";
hexInt = "0x%x";
string = "---%s---";
myPackage.Point = name "{" x ", " y:hexInt "}";
to the value myPackage.Point{"foo", 3, 15} results in
---foo---{3, 0xf}
Finally, an operand may be a grouped, optional, or repeated expression.
A grouped expression ("group") groups a more complex expression (body)
so that it can be used in place of a single operand:
Group = "(" [ Indentation ">>" ] Body ")" .
Indentation = Expression .
Body = Expression .
A group body may be prefixed by an indentation expression followed by '>>'.
The indentation expression is applied to the current value like any other
expression and the result, if not nil, is appended to the current indentation
during the evaluation of the body (see also formatting state, below).
An optional expression ("option") is enclosed in '[]' brackets.
Option = "[" Body "]" .
An option evaluates to its body, except that if the body evaluates to nil,
the option expression evaluates to an empty []byte. Thus an option's purpose
is to protect the expression containing the option from a nil operand.
A repeated expression ("repetition") is enclosed in '{}' braces.
Repetition = "{" Body [ "/" Separator ] "}" .
Separator = Expression .
A repeated expression is evaluated as follows: The body is evaluated
repeatedly and its results are concatenated until the body evaluates
to nil. The result of the repetition is the (possibly empty) concatenation,
but it is never nil. An implicit index is supplied for the evaluation of
the body: that index is used to address elements of arrays or slices. If
the corresponding elements do not exist, the field denoting the element
evaluates to nil (which in turn may terminate the repetition).
The body of a repetition may be followed by a '/' and a "separator"
expression. If the separator is present, it is invoked between repetitions
of the body.
The following example shows a complete format specification for formatting
a slice of unnamed type. Applying the specification
int = "%b";
array = { * / ", " }; // array is the type name for an unnamed slice
to the value '[]int{2, 3, 5, 7}' results in
10, 11, 101, 111
Default rule: If a format rule named 'default' is present, it is used for
formatting a value if no other rule was found. A common default rule is
default = "%v"
to provide default formatting for basic types without having to specify
a specific rule for each basic type.
Global separator rule: If a format rule named '/' is present, it is
invoked with the current value between literals. If the separator
expression evaluates to nil, it is ignored.
For instance, a global separator rule may be used to punctuate a sequence
of values with commas. The rules:
default = "%v";
/ = ", ";
will format an argument list by printing each one in its default format,
separated by a comma and a space.
*/
package datafmt
import (
"bytes"
"fmt"
"go/token"
"io"
"os"
"reflect"
"runtime"
)
// ----------------------------------------------------------------------------
// Format representation
// Custom formatters implement the Formatter function type.
// A formatter is invoked with the current formatting state, the
// value to format, and the rule name under which the formatter
// was installed (the same formatter function may be installed
// under different names). The formatter may access the current state
// to guide formatting and use State.Write to append to the state's
// output.
//
// A formatter must return a boolean value indicating if it evaluated
// to a non-nil value (true), or a nil value (false).
//
type Formatter func(state *State, value interface{}, ruleName string) bool
// A FormatterMap is a set of custom formatters.
// It maps a rule name to a formatter function.
//
type FormatterMap map[string]Formatter
// A parsed format expression is built from the following nodes.
//
type (
expr interface{}
alternatives []expr // x | y | z
sequence []expr // x y z
literal [][]byte // a list of string segments, possibly starting with '%'
field struct {
fieldName string // including "@", "*"
ruleName string // "" if no rule name specified
}
group struct {
indent, body expr // (indent >> body)
}
option struct {
body expr // [body]
}
repetition struct {
body, separator expr // {body / separator}
}
custom struct {
ruleName string
fun Formatter
}
)
// A Format is the result of parsing a format specification.
// The format may be applied repeatedly to format values.
//
type Format map[string]expr
// ----------------------------------------------------------------------------
// Formatting
// An application-specific environment may be provided to Format.Apply;
// the environment is available inside custom formatters via State.Env().
// Environments must implement copying; the Copy method must return an
// complete copy of the receiver. This is necessary so that the formatter
// can save and restore an environment (in case of an absent expression).
//
// If the Environment doesn't change during formatting (this is under
// control of the custom formatters), the Copy function can simply return
// the receiver, and thus can be very light-weight.
//
type Environment interface {
Copy() Environment
}
// State represents the current formatting state.
// It is provided as argument to custom formatters.
//
type State struct {
fmt Format // format in use
env Environment // user-supplied environment
errors chan os.Error // not chan *Error (errors <- nil would be wrong!)
hasOutput bool // true after the first literal has been written
indent bytes.Buffer // current indentation
output bytes.Buffer // format output
linePos token.Position // position of line beginning (Column == 0)
default_ expr // possibly nil
separator expr // possibly nil
}
func newState(fmt Format, env Environment, errors chan os.Error) *State {
s := new(State)
s.fmt = fmt
s.env = env
s.errors = errors
s.linePos = token.Position{Line: 1}
// if we have a default rule, cache it's expression for fast access
if x, found := fmt["default"]; found {
s.default_ = x
}
// if we have a global separator rule, cache it's expression for fast access
if x, found := fmt["/"]; found {
s.separator = x
}
return s
}
// Env returns the environment passed to Format.Apply.
func (s *State) Env() interface{} { return s.env }
// LinePos returns the position of the current line beginning
// in the state's output buffer. Line numbers start at 1.
//
func (s *State) LinePos() token.Position { return s.linePos }
// Pos returns the position of the next byte to be written to the
// output buffer. Line numbers start at 1.
//
func (s *State) Pos() token.Position {
offs := s.output.Len()
return token.Position{Line: s.linePos.Line, Column: offs - s.linePos.Offset, Offset: offs}
}
// Write writes data to the output buffer, inserting the indentation
// string after each newline or form feed character. It cannot return an error.
//
func (s *State) Write(data []byte) (int, os.Error) {
n := 0
i0 := 0
for i, ch := range data {
if ch == '\n' || ch == '\f' {
// write text segment and indentation
n1, _ := s.output.Write(data[i0 : i+1])
n2, _ := s.output.Write(s.indent.Bytes())
n += n1 + n2
i0 = i + 1
s.linePos.Offset = s.output.Len()
s.linePos.Line++
}
}
n3, _ := s.output.Write(data[i0:])
return n + n3, nil
}
type checkpoint struct {
env Environment
hasOutput bool
outputLen int
linePos token.Position
}
func (s *State) save() checkpoint {
saved := checkpoint{nil, s.hasOutput, s.output.Len(), s.linePos}
if s.env != nil {
saved.env = s.env.Copy()
}
return saved
}
func (s *State) restore(m checkpoint) {
s.env = m.env
s.output.Truncate(m.outputLen)
}
func (s *State) error(msg string) {
s.errors <- os.NewError(msg)
runtime.Goexit()
}
// TODO At the moment, unnamed types are simply mapped to the default
// names below. For instance, all unnamed arrays are mapped to
// 'array' which is not really sufficient. Eventually one may want
// to be able to specify rules for say an unnamed slice of T.
//
func typename(typ reflect.Type) string {
switch typ.Kind() {
case reflect.Array:
return "array"
case reflect.Slice:
return "array"
case reflect.Chan:
return "chan"
case reflect.Func:
return "func"
case reflect.Interface:
return "interface"
case reflect.Map:
return "map"
case reflect.Ptr:
return "ptr"
}
return typ.String()
}
func (s *State) getFormat(name string) expr {
if fexpr, found := s.fmt[name]; found {
return fexpr
}
if s.default_ != nil {
return s.default_
}
s.error(fmt.Sprintf("no format rule for type: '%s'", name))
return nil
}
// eval applies a format expression fexpr to a value. If the expression
// evaluates internally to a non-nil []byte, that slice is appended to
// the state's output buffer and eval returns true. Otherwise, eval
// returns false and the state remains unchanged.
//
func (s *State) eval(fexpr expr, value reflect.Value, index int) bool {
// an empty format expression always evaluates
// to a non-nil (but empty) []byte
if fexpr == nil {
return true
}
switch t := fexpr.(type) {
case alternatives:
// append the result of the first alternative that evaluates to
// a non-nil []byte to the state's output
mark := s.save()
for _, x := range t {
if s.eval(x, value, index) {
return true
}
s.restore(mark)
}
return false
case sequence:
// append the result of all operands to the state's output
// unless a nil result is encountered
mark := s.save()
for _, x := range t {
if !s.eval(x, value, index) {
s.restore(mark)
return false
}
}
return true
case literal:
// write separator, if any
if s.hasOutput {
// not the first literal
if s.separator != nil {
sep := s.separator // save current separator
s.separator = nil // and disable it (avoid recursion)
mark := s.save()
if !s.eval(sep, value, index) {
s.restore(mark)
}
s.separator = sep // enable it again
}
}
s.hasOutput = true
// write literal segments
for _, lit := range t {
if len(lit) > 1 && lit[0] == '%' {
// segment contains a %-format at the beginning
if lit[1] == '%' {
// "%%" is printed as a single "%"
s.Write(lit[1:])
} else {
// use s instead of s.output to get indentation right
fmt.Fprintf(s, string(lit), value.Interface())
}
} else {
// segment contains no %-formats
s.Write(lit)
}
}
return true // a literal never evaluates to nil
case *field:
// determine field value
switch t.fieldName {
case "@":
// field value is current value
case "*":
// indirection: operation is type-specific
switch v := value; v.Kind() {
case reflect.Array:
if v.Len() <= index {
return false
}
value = v.Index(index)
case reflect.Slice:
if v.IsNil() || v.Len() <= index {
return false
}
value = v.Index(index)
case reflect.Map:
s.error("reflection support for maps incomplete")
case reflect.Ptr:
if v.IsNil() {
return false
}
value = v.Elem()
case reflect.Interface:
if v.IsNil() {
return false
}
value = v.Elem()
case reflect.Chan:
s.error("reflection support for chans incomplete")
case reflect.Func:
s.error("reflection support for funcs incomplete")
default:
s.error(fmt.Sprintf("error: * does not apply to `%s`", value.Type()))
}
default:
// value is value of named field
var field reflect.Value
if sval := value; sval.Kind() == reflect.Struct {
field = sval.FieldByName(t.fieldName)
if !field.IsValid() {
// TODO consider just returning false in this case
s.error(fmt.Sprintf("error: no field `%s` in `%s`", t.fieldName, value.Type()))
}
}
value = field
}
// determine rule
ruleName := t.ruleName
if ruleName == "" {
// no alternate rule name, value type determines rule
ruleName = typename(value.Type())
}
fexpr = s.getFormat(ruleName)
mark := s.save()
if !s.eval(fexpr, value, index) {
s.restore(mark)
return false
}
return true
case *group:
// remember current indentation
indentLen := s.indent.Len()
// update current indentation
mark := s.save()
s.eval(t.indent, value, index)
// if the indentation evaluates to nil, the state's output buffer
// didn't change - either way it's ok to append the difference to
// the current indentation
s.indent.Write(s.output.Bytes()[mark.outputLen:s.output.Len()])
s.restore(mark)
// format group body
mark = s.save()
b := true
if !s.eval(t.body, value, index) {
s.restore(mark)
b = false
}
// reset indentation
s.indent.Truncate(indentLen)
return b
case *option:
// evaluate the body and append the result to the state's output
// buffer unless the result is nil
mark := s.save()
if !s.eval(t.body, value, 0) { // TODO is 0 index correct?
s.restore(mark)
}
return true // an option never evaluates to nil
case *repetition:
// evaluate the body and append the result to the state's output
// buffer until a result is nil
for i := 0; ; i++ {
mark := s.save()
// write separator, if any
if i > 0 && t.separator != nil {
// nil result from separator is ignored
mark := s.save()
if !s.eval(t.separator, value, i) {
s.restore(mark)
}
}
if !s.eval(t.body, value, i) {
s.restore(mark)
break
}
}
return true // a repetition never evaluates to nil
case *custom:
// invoke the custom formatter to obtain the result
mark := s.save()
if !t.fun(s, value.Interface(), t.ruleName) {
s.restore(mark)
return false
}
return true
}
panic("unreachable")
return false
}
// Eval formats each argument according to the format
// f and returns the resulting []byte and os.Error. If
// an error occurred, the []byte contains the partially
// formatted result. An environment env may be passed
// in which is available in custom formatters through
// the state parameter.
//
func (f Format) Eval(env Environment, args ...interface{}) ([]byte, os.Error) {
if f == nil {
return nil, os.NewError("format is nil")
}
errors := make(chan os.Error)
s := newState(f, env, errors)
go func() {
for _, v := range args {
fld := reflect.ValueOf(v)
if !fld.IsValid() {
errors <- os.NewError("nil argument")
return
}
mark := s.save()
if !s.eval(s.getFormat(typename(fld.Type())), fld, 0) { // TODO is 0 index correct?
s.restore(mark)
}
}
errors <- nil // no errors
}()
err := <-errors
return s.output.Bytes(), err
}
// ----------------------------------------------------------------------------
// Convenience functions
// Fprint formats each argument according to the format f
// and writes to w. The result is the total number of bytes
// written and an os.Error, if any.
//
func (f Format) Fprint(w io.Writer, env Environment, args ...interface{}) (int, os.Error) {
data, err := f.Eval(env, args...)
if err != nil {
// TODO should we print partial result in case of error?
return 0, err
}
return w.Write(data)
}
// Print formats each argument according to the format f
// and writes to standard output. The result is the total
// number of bytes written and an os.Error, if any.
//
func (f Format) Print(args ...interface{}) (int, os.Error) {
return f.Fprint(os.Stdout, nil, args...)
}
// Sprint formats each argument according to the format f
// and returns the resulting string. If an error occurs
// during formatting, the result string contains the
// partially formatted result followed by an error message.
//
func (f Format) Sprint(args ...interface{}) string {
var buf bytes.Buffer
_, err := f.Fprint(&buf, nil, args...)
if err != nil {
var i interface{} = args
fmt.Fprintf(&buf, "--- Sprint(%s) failed: %v", fmt.Sprint(i), err)
}
return buf.String()
}

351
src/pkg/exp/datafmt/datafmt_test.go
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@ -1,351 +0,0 @@
// 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 datafmt
import (
"fmt"
"testing"
"go/token"
)
var fset = token.NewFileSet()
func parse(t *testing.T, form string, fmap FormatterMap) Format {
f, err := Parse(fset, "", []byte(form), fmap)
if err != nil {
t.Errorf("Parse(%s): %v", form, err)
return nil
}
return f
}
func verify(t *testing.T, f Format, expected string, args ...interface{}) {
if f == nil {
return // allow other tests to run
}
result := f.Sprint(args...)
if result != expected {
t.Errorf(
"result : `%s`\nexpected: `%s`\n\n",
result, expected)
}
}
func formatter(s *State, value interface{}, rule_name string) bool {
switch rule_name {
case "/":
fmt.Fprintf(s, "%d %d %d", s.Pos().Line, s.LinePos().Column, s.Pos().Column)
return true
case "blank":
s.Write([]byte{' '})
return true
case "int":
if value.(int)&1 == 0 {
fmt.Fprint(s, "even ")
} else {
fmt.Fprint(s, "odd ")
}
return true
case "nil":
return false
case "testing.T":
s.Write([]byte("testing.T"))
return true
}
panic("unreachable")
return false
}
func TestCustomFormatters(t *testing.T) {
fmap0 := FormatterMap{"/": formatter}
fmap1 := FormatterMap{"int": formatter, "blank": formatter, "nil": formatter}
fmap2 := FormatterMap{"testing.T": formatter}
f := parse(t, `int=`, fmap0)
verify(t, f, ``, 1, 2, 3)
f = parse(t, `int="#"`, nil)
verify(t, f, `###`, 1, 2, 3)
f = parse(t, `int="#";string="%s"`, fmap0)
verify(t, f, "#1 0 1#1 0 7#1 0 13\n2 0 0foo2 0 8\n", 1, 2, 3, "\n", "foo", "\n")
f = parse(t, ``, fmap1)
verify(t, f, `even odd even odd `, 0, 1, 2, 3)
f = parse(t, `/ =@:blank; float64="#"`, fmap1)
verify(t, f, `# # #`, 0.0, 1.0, 2.0)
f = parse(t, `float64=@:nil`, fmap1)
verify(t, f, ``, 0.0, 1.0, 2.0)
f = parse(t, `testing "testing"; ptr=*`, fmap2)
verify(t, f, `testing.T`, t)
// TODO needs more tests
}
// ----------------------------------------------------------------------------
// Formatting of basic and simple composite types
func check(t *testing.T, form, expected string, args ...interface{}) {
f := parse(t, form, nil)
if f == nil {
return // allow other tests to run
}
result := f.Sprint(args...)
if result != expected {
t.Errorf(
"format : %s\nresult : `%s`\nexpected: `%s`\n\n",
form, result, expected)
}
}
func TestBasicTypes(t *testing.T) {
check(t, ``, ``)
check(t, `bool=":%v"`, `:true:false`, true, false)
check(t, `int="%b %d %o 0x%x"`, `101010 42 52 0x2a`, 42)
check(t, `int="%"`, `%`, 42)
check(t, `int="%%"`, `%`, 42)
check(t, `int="**%%**"`, `**%**`, 42)
check(t, `int="%%%%%%"`, `%%%`, 42)
check(t, `int="%%%d%%"`, `%42%`, 42)
const i = -42
const is = `-42`
check(t, `int ="%d"`, is, i)
check(t, `int8 ="%d"`, is, int8(i))
check(t, `int16="%d"`, is, int16(i))
check(t, `int32="%d"`, is, int32(i))
check(t, `int64="%d"`, is, int64(i))
const u = 42
const us = `42`
check(t, `uint ="%d"`, us, uint(u))
check(t, `uint8 ="%d"`, us, uint8(u))
check(t, `uint16="%d"`, us, uint16(u))
check(t, `uint32="%d"`, us, uint32(u))
check(t, `uint64="%d"`, us, uint64(u))
const f = 3.141592
const fs = `3.141592`
check(t, `float64="%g"`, fs, f)
check(t, `float32="%g"`, fs, float32(f))
check(t, `float64="%g"`, fs, float64(f))
}
func TestArrayTypes(t *testing.T) {
var a0 [10]int
check(t, `array="array";`, `array`, a0)
a1 := [...]int{1, 2, 3}
check(t, `array="array";`, `array`, a1)
check(t, `array={*}; int="%d";`, `123`, a1)
check(t, `array={* / ", "}; int="%d";`, `1, 2, 3`, a1)
check(t, `array={* / *}; int="%d";`, `12233`, a1)
a2 := []interface{}{42, "foo", 3.14}
check(t, `array={* / ", "}; interface=*; string="bar"; default="%v";`, `42, bar, 3.14`, a2)
}
func TestChanTypes(t *testing.T) {
var c0 chan int
check(t, `chan="chan"`, `chan`, c0)
c1 := make(chan int)
go func() { c1 <- 42 }()
check(t, `chan="chan"`, `chan`, c1)
// check(t, `chan=*`, `42`, c1); // reflection support for chans incomplete
}
func TestFuncTypes(t *testing.T) {
var f0 func() int
check(t, `func="func"`, `func`, f0)
f1 := func() int { return 42 }
check(t, `func="func"`, `func`, f1)
// check(t, `func=*`, `42`, f1); // reflection support for funcs incomplete
}
func TestMapTypes(t *testing.T) {
var m0 map[string]int
check(t, `map="map"`, `map`, m0)
m1 := map[string]int{}
check(t, `map="map"`, `map`, m1)
// check(t, `map=*`, ``, m1); // reflection support for maps incomplete
}
func TestPointerTypes(t *testing.T) {
var p0 *int
check(t, `ptr="ptr"`, `ptr`, p0)
check(t, `ptr=*`, ``, p0)
check(t, `ptr=*|"nil"`, `nil`, p0)
x := 99991
p1 := &x
check(t, `ptr="ptr"`, `ptr`, p1)
check(t, `ptr=*; int="%d"`, `99991`, p1)
}
func TestDefaultRule(t *testing.T) {
check(t, `default="%v"`, `42foo3.14`, 42, "foo", 3.14)
check(t, `default="%v"; int="%x"`, `abcdef`, 10, 11, 12, 13, 14, 15)
check(t, `default="%v"; int="%x"`, `ab**ef`, 10, 11, "**", 14, 15)
check(t, `default="%x"; int=@:default`, `abcdef`, 10, 11, 12, 13, 14, 15)
}
func TestGlobalSeparatorRule(t *testing.T) {
check(t, `int="%d"; / ="-"`, `1-2-3-4`, 1, 2, 3, 4)
check(t, `int="%x%x"; / ="*"`, `aa*aa`, 10, 10)
}
// ----------------------------------------------------------------------------
// Formatting of a struct
type T1 struct {
a int
}
const F1 = `datafmt "datafmt";` +
`int = "%d";` +
`datafmt.T1 = "<" a ">";`
func TestStruct1(t *testing.T) { check(t, F1, "<42>", T1{42}) }
// ----------------------------------------------------------------------------
// Formatting of a struct with an optional field (ptr)
type T2 struct {
s string
p *T1
}
const F2a = F1 +
`string = "%s";` +
`ptr = *;` +
`datafmt.T2 = s ["-" p "-"];`
const F2b = F1 +
`string = "%s";` +
`ptr = *;` +
`datafmt.T2 = s ("-" p "-" | "empty");`
func TestStruct2(t *testing.T) {
check(t, F2a, "foo", T2{"foo", nil})
check(t, F2a, "bar-<17>-", T2{"bar", &T1{17}})
check(t, F2b, "fooempty", T2{"foo", nil})
}
// ----------------------------------------------------------------------------
// Formatting of a struct with a repetitive field (slice)
type T3 struct {
s string
a []int
}
const F3a = `datafmt "datafmt";` +
`default = "%v";` +
`array = *;` +
`datafmt.T3 = s {" " a a / ","};`
const F3b = `datafmt "datafmt";` +
`int = "%d";` +
`string = "%s";` +
`array = *;` +
`nil = ;` +
`empty = *:nil;` +
`datafmt.T3 = s [a:empty ": " {a / "-"}]`
func TestStruct3(t *testing.T) {
check(t, F3a, "foo", T3{"foo", nil})
check(t, F3a, "foo 00, 11, 22", T3{"foo", []int{0, 1, 2}})
check(t, F3b, "bar", T3{"bar", nil})
check(t, F3b, "bal: 2-3-5", T3{"bal", []int{2, 3, 5}})
}
// ----------------------------------------------------------------------------
// Formatting of a struct with alternative field
type T4 struct {
x *int
a []int
}
const F4a = `datafmt "datafmt";` +
`int = "%d";` +
`ptr = *;` +
`array = *;` +
`nil = ;` +
`empty = *:nil;` +
`datafmt.T4 = "<" (x:empty x | "-") ">" `
const F4b = `datafmt "datafmt";` +
`int = "%d";` +
`ptr = *;` +
`array = *;` +
`nil = ;` +
`empty = *:nil;` +
`datafmt.T4 = "<" (a:empty {a / ", "} | "-") ">" `
func TestStruct4(t *testing.T) {
x := 7
check(t, F4a, "<->", T4{nil, nil})
check(t, F4a, "<7>", T4{&x, nil})
check(t, F4b, "<->", T4{nil, nil})
check(t, F4b, "<2, 3, 7>", T4{nil, []int{2, 3, 7}})
}
// ----------------------------------------------------------------------------
// Formatting a struct (documentation example)
type Point struct {
name string
x, y int
}
const FPoint = `datafmt "datafmt";` +
`int = "%d";` +
`hexInt = "0x%x";` +
`string = "---%s---";` +
`datafmt.Point = name "{" x ", " y:hexInt "}";`
func TestStructPoint(t *testing.T) {
p := Point{"foo", 3, 15}
check(t, FPoint, "---foo---{3, 0xf}", p)
}
// ----------------------------------------------------------------------------
// Formatting a slice (documentation example)
const FSlice = `int = "%b";` +
`array = { * / ", " }`
func TestSlice(t *testing.T) { check(t, FSlice, "10, 11, 101, 111", []int{2, 3, 5, 7}) }
// TODO add more tests

386
src/pkg/exp/datafmt/parser.go
View File

@ -1,386 +0,0 @@
// 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 datafmt
import (
"container/vector"
"go/scanner"
"go/token"
"os"
"strconv"
"strings"
)
// ----------------------------------------------------------------------------
// Parsing
type parser struct {
scanner.ErrorVector
scanner scanner.Scanner
file *token.File
pos token.Pos // token position
tok token.Token // one token look-ahead
lit string // token literal
packs map[string]string // PackageName -> ImportPath
rules map[string]expr // RuleName -> Expression
}
func (p *parser) next() {
p.pos, p.tok, p.lit = p.scanner.Scan()
switch p.tok {
case token.CHAN, token.FUNC, token.INTERFACE, token.MAP, token.STRUCT:
// Go keywords for composite types are type names
// returned by reflect. Accept them as identifiers.
p.tok = token.IDENT // p.lit is already set correctly
}
}
func (p *parser) init(fset *token.FileSet, filename string, src []byte) {
p.ErrorVector.Reset()
p.file = fset.AddFile(filename, fset.Base(), len(src))
p.scanner.Init(p.file, src, p, scanner.AllowIllegalChars) // return '@' as token.ILLEGAL w/o error message
p.next() // initializes pos, tok, lit
p.packs = make(map[string]string)
p.rules = make(map[string]expr)
}
func (p *parser) error(pos token.Pos, msg string) {
p.Error(p.file.Position(pos), msg)
}
func (p *parser) errorExpected(pos token.Pos, msg string) {
msg = "expected " + msg
if pos == p.pos {
// the error happened at the current position;
// make the error message more specific
msg += ", found '" + p.tok.String() + "'"
if p.tok.IsLiteral() {
msg += " " + p.lit
}
}
p.error(pos, msg)
}
func (p *parser) expect(tok token.Token) token.Pos {
pos := p.pos
if p.tok != tok {
p.errorExpected(pos, "'"+tok.String()+"'")
}
p.next() // make progress in any case
return pos
}
func (p *parser) parseIdentifier() string {
name := p.lit
p.expect(token.IDENT)
return name
}
func (p *parser) parseTypeName() (string, bool) {
pos := p.pos
name, isIdent := p.parseIdentifier(), true
if p.tok == token.PERIOD {
// got a package name, lookup package
if importPath, found := p.packs[name]; found {
name = importPath
} else {
p.error(pos, "package not declared: "+name)
}
p.next()
name, isIdent = name+"."+p.parseIdentifier(), false
}
return name, isIdent
}
// Parses a rule name and returns it. If the rule name is
// a package-qualified type name, the package name is resolved.
// The 2nd result value is true iff the rule name consists of a
// single identifier only (and thus could be a package name).
//
func (p *parser) parseRuleName() (string, bool) {
name, isIdent := "", false
switch p.tok {
case token.IDENT:
name, isIdent = p.parseTypeName()
case token.DEFAULT:
name = "default"
p.next()
case token.QUO:
name = "/"
p.next()
default:
p.errorExpected(p.pos, "rule name")
p.next() // make progress in any case
}
return name, isIdent
}
func (p *parser) parseString() string {
s := ""
if p.tok == token.STRING {
s, _ = strconv.Unquote(p.lit)
// Unquote may fail with an error, but only if the scanner found
// an illegal string in the first place. In this case the error
// has already been reported.
p.next()
return s
} else {
p.expect(token.STRING)
}
return s
}
func (p *parser) parseLiteral() literal {
s := []byte(p.parseString())
// A string literal may contain %-format specifiers. To simplify
// and speed up printing of the literal, split it into segments
// that start with "%" possibly followed by a last segment that
// starts with some other character.
var list vector.Vector
i0 := 0
for i := 0; i < len(s); i++ {
if s[i] == '%' && i+1 < len(s) {
// the next segment starts with a % format
if i0 < i {
// the current segment is not empty, split it off
list.Push(s[i0:i])
i0 = i
}
i++ // skip %; let loop skip over char after %
}
}
// the final segment may start with any character
// (it is empty iff the string is empty)
list.Push(s[i0:])
// convert list into a literal
lit := make(literal, list.Len())
for i := 0; i < list.Len(); i++ {
lit[i] = list.At(i).([]byte)
}
return lit
}
func (p *parser) parseField() expr {
var fname string
switch p.tok {
case token.ILLEGAL:
if p.lit != "@" {
return nil
}
fname = "@"
p.next()
case token.MUL:
fname = "*"
p.next()
case token.IDENT:
fname = p.parseIdentifier()
default:
return nil
}
var ruleName string
if p.tok == token.COLON {
p.next()
ruleName, _ = p.parseRuleName()
}
return &field{fname, ruleName}
}
func (p *parser) parseOperand() (x expr) {
switch p.tok {
case token.STRING:
x = p.parseLiteral()
case token.LPAREN:
p.next()
x = p.parseExpression()
if p.tok == token.SHR {
p.next()
x = &group{x, p.parseExpression()}
}
p.expect(token.RPAREN)
case token.LBRACK:
p.next()
x = &option{p.parseExpression()}
p.expect(token.RBRACK)
case token.LBRACE:
p.next()
x = p.parseExpression()
var div expr
if p.tok == token.QUO {
p.next()
div = p.parseExpression()
}
x = &repetition{x, div}
p.expect(token.RBRACE)
default:
x = p.parseField() // may be nil
}
return x
}
func (p *parser) parseSequence() expr {
var list vector.Vector
for x := p.parseOperand(); x != nil; x = p.parseOperand() {
list.Push(x)
}
// no need for a sequence if list.Len() < 2
switch list.Len() {
case 0:
return nil
case 1:
return list.At(0).(expr)
}
// convert list into a sequence
seq := make(sequence, list.Len())
for i := 0; i < list.Len(); i++ {
seq[i] = list.At(i).(expr)
}
return seq
}
func (p *parser) parseExpression() expr {
var list vector.Vector
for {
x := p.parseSequence()
if x != nil {
list.Push(x)
}
if p.tok != token.OR {
break
}
p.next()
}
// no need for an alternatives if list.Len() < 2
switch list.Len() {
case 0:
return nil
case 1:
return list.At(0).(expr)
}
// convert list into a alternatives
alt := make(alternatives, list.Len())
for i := 0; i < list.Len(); i++ {
alt[i] = list.At(i).(expr)
}
return alt
}
func (p *parser) parseFormat() {
for p.tok != token.EOF {
pos := p.pos
name, isIdent := p.parseRuleName()
switch p.tok {
case token.STRING:
// package declaration
importPath := p.parseString()
// add package declaration
if !isIdent {
p.error(pos, "illegal package name: "+name)
} else if _, found := p.packs[name]; !found {
p.packs[name] = importPath
} else {
p.error(pos, "package already declared: "+name)
}
case token.ASSIGN:
// format rule
p.next()
x := p.parseExpression()
// add rule
if _, found := p.rules[name]; !found {
p.rules[name] = x
} else {
p.error(pos, "format rule already declared: "+name)
}
default:
p.errorExpected(p.pos, "package declaration or format rule")
p.next() // make progress in any case
}
if p.tok == token.SEMICOLON {
p.next()
} else {
break
}
}
p.expect(token.EOF)
}
func remap(p *parser, name string) string {
i := strings.Index(name, ".")
if i >= 0 {
packageName, suffix := name[0:i], name[i:]
// lookup package
if importPath, found := p.packs[packageName]; found {
name = importPath + suffix
} else {
var invalidPos token.Position
p.Error(invalidPos, "package not declared: "+packageName)
}
}
return name
}
// Parse parses a set of format productions from source src. Custom
// formatters may be provided via a map of formatter functions. If
// there are no errors, the result is a Format and the error is nil.
// Otherwise the format is nil and a non-empty ErrorList is returned.
//
func Parse(fset *token.FileSet, filename string, src []byte, fmap FormatterMap) (Format, os.Error) {
// parse source
var p parser
p.init(fset, filename, src)
p.parseFormat()
// add custom formatters, if any
for name, form := range fmap {
name = remap(&p, name)
if _, found := p.rules[name]; !found {
p.rules[name] = &custom{name, form}
} else {
var invalidPos token.Position
p.Error(invalidPos, "formatter already declared: "+name)
}
}
return p.rules, p.GetError(scanner.NoMultiples)
}

16
src/pkg/fmt/fmt_test.go
View File

@ -62,7 +62,7 @@ type I int
func (i I) String() string { return Sprintf("<%d>", int(i)) }
type B struct {
i I
I I
j int
}
@ -84,8 +84,8 @@ func (g G) GoString() string {
}
type S struct {
f F // a struct field that Formats
g G // a struct field that GoStrings
F F // a struct field that Formats
G G // a struct field that GoStrings
}
// A type with a String method with pointer receiver for testing %p
@ -322,8 +322,8 @@ var fmttests = []struct {
{"%+v", A{1, 2, "a", []int{1, 2}}, `{i:1 j:2 s:a x:[1 2]}`},
// +v on structs with Stringable items
{"%+v", B{1, 2}, `{i:<1> j:2}`},
{"%+v", C{1, B{2, 3}}, `{i:1 B:{i:<2> j:3}}`},
{"%+v", B{1, 2}, `{I:<1> j:2}`},
{"%+v", C{1, B{2, 3}}, `{i:1 B:{I:<2> j:3}}`},
// q on Stringable items
{"%s", I(23), `<23>`},
@ -339,7 +339,7 @@ var fmttests = []struct {
{"%#v", uint64(1<<64 - 1), "0xffffffffffffffff"},
{"%#v", 1000000000, "1000000000"},
{"%#v", map[string]int{"a": 1, "b": 2}, `map[string] int{"a":1, "b":2}`},
{"%#v", map[string]B{"a": {1, 2}, "b": {3, 4}}, `map[string] fmt_test.B{"a":fmt_test.B{i:1, j:2}, "b":fmt_test.B{i:3, j:4}}`},
{"%#v", map[string]B{"a": {1, 2}, "b": {3, 4}}, `map[string] fmt_test.B{"a":fmt_test.B{I:1, j:2}, "b":fmt_test.B{I:3, j:4}}`},
{"%#v", []string{"a", "b"}, `[]string{"a", "b"}`},
// slices with other formats
@ -374,11 +374,11 @@ var fmttests = []struct {
// Formatter
{"%x", F(1), "<x=F(1)>"},
{"%x", G(2), "2"},
{"%+v", S{F(4), G(5)}, "{f:<v=F(4)> g:5}"},
{"%+v", S{F(4), G(5)}, "{F:<v=F(4)> G:5}"},
// GoStringer
{"%#v", G(6), "GoString(6)"},
{"%#v", S{F(7), G(8)}, "fmt_test.S{f:<v=F(7)>, g:GoString(8)}"},
{"%#v", S{F(7), G(8)}, "fmt_test.S{F:<v=F(7)>, G:GoString(8)}"},
// %T
{"%T", (4 - 3i), "complex128"},

245
src/pkg/fmt/print.go
View File

@ -259,10 +259,8 @@ func Sprintln(a ...interface{}) string {
// the thing inside the interface, not the interface itself.
func getField(v reflect.Value, i int) reflect.Value {
val := v.Field(i)
if i := val; i.Kind() == reflect.Interface {
if inter := i.Interface(); inter != nil {
return reflect.ValueOf(inter)
}
if val.Kind() == reflect.Interface && !val.IsNil() {
val = val.Elem()
}
return val
}
@ -289,27 +287,32 @@ func (p *pp) unknownType(v interface{}) {
p.buf.WriteByte('?')
}
func (p *pp) badVerb(verb int, val interface{}) {
func (p *pp) badVerb(verb int, val interface{}, val1 reflect.Value) {
p.add('%')
p.add('!')
p.add(verb)
p.add('(')
if val == nil {
p.buf.Write(nilAngleBytes)
} else {
switch {
case val != nil:
p.buf.WriteString(reflect.TypeOf(val).String())
p.add('=')
p.printField(val, 'v', false, false, 0)
case val1.IsValid():
p.buf.WriteString(val1.Type().String())
p.add('=')
p.printValue(val1, 'v', false, false, 0)
default:
p.buf.Write(nilAngleBytes)
}
p.add(')')
}
func (p *pp) fmtBool(v bool, verb int, value interface{}) {
func (p *pp) fmtBool(v bool, verb int, value interface{}, value1 reflect.Value) {
switch verb {
case 't', 'v':
p.fmt.fmt_boolean(v)
default:
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
}
@ -323,7 +326,7 @@ func (p *pp) fmtC(c int64) {
p.fmt.pad(p.runeBuf[0:w])
}
func (p *pp) fmtInt64(v int64, verb int, value interface{}) {
func (p *pp) fmtInt64(v int64, verb int, value interface{}, value1 reflect.Value) {
switch verb {
case 'b':
p.fmt.integer(v, 2, signed, ldigits)
@ -337,7 +340,7 @@ func (p *pp) fmtInt64(v int64, verb int, value interface{}) {
if 0 <= v && v <= unicode.MaxRune {
p.fmt.fmt_qc(v)
} else {
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
case 'x':
p.fmt.integer(v, 16, signed, ldigits)
@ -346,7 +349,7 @@ func (p *pp) fmtInt64(v int64, verb int, value interface{}) {
case 'X':
p.fmt.integer(v, 16, signed, udigits)
default:
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
}
@ -376,7 +379,7 @@ func (p *pp) fmtUnicode(v int64) {
p.fmt.precPresent = precPresent
}
func (p *pp) fmtUint64(v uint64, verb int, goSyntax bool, value interface{}) {
func (p *pp) fmtUint64(v uint64, verb int, goSyntax bool, value interface{}, value1 reflect.Value) {
switch verb {
case 'b':
p.fmt.integer(int64(v), 2, unsigned, ldigits)
@ -396,7 +399,7 @@ func (p *pp) fmtUint64(v uint64, verb int, goSyntax bool, value interface{}) {
if 0 <= v && v <= unicode.MaxRune {
p.fmt.fmt_qc(int64(v))
} else {
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
case 'x':
p.fmt.integer(int64(v), 16, unsigned, ldigits)
@ -405,11 +408,11 @@ func (p *pp) fmtUint64(v uint64, verb int, goSyntax bool, value interface{}) {
case 'U':
p.fmtUnicode(int64(v))
default:
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
}
func (p *pp) fmtFloat32(v float32, verb int, value interface{}) {
func (p *pp) fmtFloat32(v float32, verb int, value interface{}, value1 reflect.Value) {
switch verb {
case 'b':
p.fmt.fmt_fb32(v)
@ -424,11 +427,11 @@ func (p *pp) fmtFloat32(v float32, verb int, value interface{}) {
case 'G':
p.fmt.fmt_G32(v)
default:
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
}
func (p *pp) fmtFloat64(v float64, verb int, value interface{}) {
func (p *pp) fmtFloat64(v float64, verb int, value interface{}, value1 reflect.Value) {
switch verb {
case 'b':
p.fmt.fmt_fb64(v)
@ -443,33 +446,33 @@ func (p *pp) fmtFloat64(v float64, verb int, value interface{}) {
case 'G':
p.fmt.fmt_G64(v)
default:
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
}
func (p *pp) fmtComplex64(v complex64, verb int, value interface{}) {
func (p *pp) fmtComplex64(v complex64, verb int, value interface{}, value1 reflect.Value) {
switch verb {
case 'e', 'E', 'f', 'F', 'g', 'G':
p.fmt.fmt_c64(v, verb)
case 'v':
p.fmt.fmt_c64(v, 'g')
default:
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
}
func (p *pp) fmtComplex128(v complex128, verb int, value interface{}) {
func (p *pp) fmtComplex128(v complex128, verb int, value interface{}, value1 reflect.Value) {
switch verb {
case 'e', 'E', 'f', 'F', 'g', 'G':
p.fmt.fmt_c128(v, verb)
case 'v':
p.fmt.fmt_c128(v, 'g')
default:
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
}
func (p *pp) fmtString(v string, verb int, goSyntax bool, value interface{}) {
func (p *pp) fmtString(v string, verb int, goSyntax bool, value interface{}, value1 reflect.Value) {
switch verb {
case 'v':
if goSyntax {
@ -486,11 +489,11 @@ func (p *pp) fmtString(v string, verb int, goSyntax bool, value interface{}) {
case 'q':
p.fmt.fmt_q(v)
default:
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
}
func (p *pp) fmtBytes(v []byte, verb int, goSyntax bool, depth int, value interface{}) {
func (p *pp) fmtBytes(v []byte, verb int, goSyntax bool, depth int, value interface{}, value1 reflect.Value) {
if verb == 'v' || verb == 'd' {
if goSyntax {
p.buf.Write(bytesBytes)
@ -525,7 +528,7 @@ func (p *pp) fmtBytes(v []byte, verb int, goSyntax bool, depth int, value interf
case 'q':
p.fmt.fmt_q(s)
default:
p.badVerb(verb, value)
p.badVerb(verb, value, value1)
}
}
@ -535,12 +538,12 @@ func (p *pp) fmtPointer(field interface{}, value reflect.Value, verb int, goSynt
case reflect.Chan, reflect.Func, reflect.Map, reflect.Ptr, reflect.Slice, reflect.UnsafePointer:
u = value.Pointer()
default:
p.badVerb(verb, field)
p.badVerb(verb, field, value)
return
}
if goSyntax {
p.add('(')
p.buf.WriteString(reflect.TypeOf(field).String())
p.buf.WriteString(value.Type().String())
p.add(')')
p.add('(')
if u == 0 {
@ -561,12 +564,48 @@ var (
uintptrBits = reflect.TypeOf(uintptr(0)).Bits()
)
func (p *pp) handleMethods(field interface{}, verb int, plus, goSyntax bool, depth int) (wasString, handled bool) {
// Is it a Formatter?
if formatter, ok := field.(Formatter); ok {
handled = true
wasString = false
formatter.Format(p, verb)
return
}
// Must not touch flags before Formatter looks at them.
if plus {
p.fmt.plus = false
}
// If we're doing Go syntax and the field knows how to supply it, take care of it now.
if goSyntax {
p.fmt.sharp = false
if stringer, ok := field.(GoStringer); ok {
wasString = false
handled = true
// Print the result of GoString unadorned.
p.fmtString(stringer.GoString(), 's', false, field, reflect.Value{})
return
}
} else {
// Is it a Stringer?
if stringer, ok := field.(Stringer); ok {
wasString = false
handled = true
p.printField(stringer.String(), verb, plus, false, depth)
return
}
}
handled = false
return
}
func (p *pp) printField(field interface{}, verb int, plus, goSyntax bool, depth int) (wasString bool) {
if field == nil {
if verb == 'T' || verb == 'v' {
p.buf.Write(nilAngleBytes)
} else {
p.badVerb(verb, field)
p.badVerb(verb, field, reflect.Value{})
}
return false
}
@ -581,115 +620,133 @@ func (p *pp) printField(field interface{}, verb int, plus, goSyntax bool, depth
p.fmtPointer(field, reflect.ValueOf(field), verb, goSyntax)
return false
}
// Is it a Formatter?
if formatter, ok := field.(Formatter); ok {
formatter.Format(p, verb)
return false // this value is not a string
}
// Must not touch flags before Formatter looks at them.
if plus {
p.fmt.plus = false
}
// If we're doing Go syntax and the field knows how to supply it, take care of it now.
if goSyntax {
p.fmt.sharp = false
if stringer, ok := field.(GoStringer); ok {
// Print the result of GoString unadorned.
p.fmtString(stringer.GoString(), 's', false, field)
return false // this value is not a string
}
} else {
// Is it a Stringer?
if stringer, ok := field.(Stringer); ok {
p.printField(stringer.String(), verb, plus, false, depth)
return false // this value is not a string
}
if wasString, handled := p.handleMethods(field, verb, plus, goSyntax, depth); handled {
return wasString
}
// Some types can be done without reflection.
switch f := field.(type) {
case bool:
p.fmtBool(f, verb, field)
p.fmtBool(f, verb, field, reflect.Value{})
return false
case float32:
p.fmtFloat32(f, verb, field)
p.fmtFloat32(f, verb, field, reflect.Value{})
return false
case float64:
p.fmtFloat64(f, verb, field)
p.fmtFloat64(f, verb, field, reflect.Value{})
return false
case complex64:
p.fmtComplex64(complex64(f), verb, field)
p.fmtComplex64(complex64(f), verb, field, reflect.Value{})
return false
case complex128:
p.fmtComplex128(f, verb, field)
p.fmtComplex128(f, verb, field, reflect.Value{})
return false
case int:
p.fmtInt64(int64(f), verb, field)
p.fmtInt64(int64(f), verb, field, reflect.Value{})
return false
case int8:
p.fmtInt64(int64(f), verb, field)
p.fmtInt64(int64(f), verb, field, reflect.Value{})
return false
case int16:
p.fmtInt64(int64(f), verb, field)
p.fmtInt64(int64(f), verb, field, reflect.Value{})
return false
case int32:
p.fmtInt64(int64(f), verb, field)
p.fmtInt64(int64(f), verb, field, reflect.Value{})
return false
case int64:
p.fmtInt64(f, verb, field)
p.fmtInt64(f, verb, field, reflect.Value{})
return false
case uint:
p.fmtUint64(uint64(f), verb, goSyntax, field)
p.fmtUint64(uint64(f), verb, goSyntax, field, reflect.Value{})
return false
case uint8:
p.fmtUint64(uint64(f), verb, goSyntax, field)
p.fmtUint64(uint64(f), verb, goSyntax, field, reflect.Value{})
return false
case uint16:
p.fmtUint64(uint64(f), verb, goSyntax, field)
p.fmtUint64(uint64(f), verb, goSyntax, field, reflect.Value{})
return false
case uint32:
p.fmtUint64(uint64(f), verb, goSyntax, field)
p.fmtUint64(uint64(f), verb, goSyntax, field, reflect.Value{})
return false
case uint64:
p.fmtUint64(f, verb, goSyntax, field)
p.fmtUint64(f, verb, goSyntax, field, reflect.Value{})
return false
case uintptr:
p.fmtUint64(uint64(f), verb, goSyntax, field)
p.fmtUint64(uint64(f), verb, goSyntax, field, reflect.Value{})
return false
case string:
p.fmtString(f, verb, goSyntax, field)
p.fmtString(f, verb, goSyntax, field, reflect.Value{})
return verb == 's' || verb == 'v'
case []byte:
p.fmtBytes(f, verb, goSyntax, depth, field)
p.fmtBytes(f, verb, goSyntax, depth, field, reflect.Value{})
return verb == 's'
}
// Need to use reflection
value := reflect.ValueOf(field)
return p.printReflectValue(reflect.ValueOf(field), verb, plus, goSyntax, depth)
}
// printValue is like printField but starts with a reflect value, not an interface{} value.
func (p *pp) printValue(value reflect.Value, verb int, plus, goSyntax bool, depth int) (wasString bool) {
if !value.IsValid() {
if verb == 'T' || verb == 'v' {
p.buf.Write(nilAngleBytes)
} else {
p.badVerb(verb, nil, value)
}
return false
}
// Special processing considerations.
// %T (the value's type) and %p (its address) are special; we always do them first.
switch verb {
case 'T':
p.printField(value.Type().String(), 's', false, false, 0)
return false
case 'p':
p.fmtPointer(nil, value, verb, goSyntax)
return false
}
// Handle values with special methods.
// Call always, even when field == nil, because handleMethods clears p.fmt.plus for us.
var field interface{}
if value.CanInterface() {
field = value.Interface()
}
if wasString, handled := p.handleMethods(field, verb, plus, goSyntax, depth); handled {
return wasString
}
return p.printReflectValue(value, verb, plus, goSyntax, depth)
}
// printReflectValue is the fallback for both printField and printValue.
// It uses reflect to print the value.
func (p *pp) printReflectValue(value reflect.Value, verb int, plus, goSyntax bool, depth int) (wasString bool) {
BigSwitch:
switch f := value; f.Kind() {
case reflect.Bool:
p.fmtBool(f.Bool(), verb, field)
p.fmtBool(f.Bool(), verb, nil, value)
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
p.fmtInt64(f.Int(), verb, field)
p.fmtInt64(f.Int(), verb, nil, value)
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
p.fmtUint64(uint64(f.Uint()), verb, goSyntax, field)
p.fmtUint64(uint64(f.Uint()), verb, goSyntax, nil, value)
case reflect.Float32, reflect.Float64:
if f.Type().Size() == 4 {
p.fmtFloat32(float32(f.Float()), verb, field)
p.fmtFloat32(float32(f.Float()), verb, nil, value)
} else {
p.fmtFloat64(float64(f.Float()), verb, field)
p.fmtFloat64(float64(f.Float()), verb, nil, value)
}
case reflect.Complex64, reflect.Complex128:
if f.Type().Size() == 8 {
p.fmtComplex64(complex64(f.Complex()), verb, field)
p.fmtComplex64(complex64(f.Complex()), verb, nil, value)
} else {
p.fmtComplex128(complex128(f.Complex()), verb, field)
p.fmtComplex128(complex128(f.Complex()), verb, nil, value)
}
case reflect.String:
p.fmtString(f.String(), verb, goSyntax, field)
p.fmtString(f.String(), verb, goSyntax, nil, value)
case reflect.Map:
if goSyntax {
p.buf.WriteString(f.Type().String())
@ -706,9 +763,9 @@ BigSwitch:
p.buf.WriteByte(' ')
}
}
p.printField(key.Interface(), verb, plus, goSyntax, depth+1)
p.printValue(key, verb, plus, goSyntax, depth+1)
p.buf.WriteByte(':')
p.printField(f.MapIndex(key).Interface(), verb, plus, goSyntax, depth+1)
p.printValue(f.MapIndex(key), verb, plus, goSyntax, depth+1)
}
if goSyntax {
p.buf.WriteByte('}')
@ -717,7 +774,7 @@ BigSwitch:
}
case reflect.Struct:
if goSyntax {
p.buf.WriteString(reflect.TypeOf(field).String())
p.buf.WriteString(value.Type().String())
}
p.add('{')
v := f
@ -736,20 +793,20 @@ BigSwitch:
p.buf.WriteByte(':')
}
}
p.printField(getField(v, i).Interface(), verb, plus, goSyntax, depth+1)
p.printValue(getField(v, i), verb, plus, goSyntax, depth+1)
}
p.buf.WriteByte('}')
case reflect.Interface:
value := f.Elem()
if !value.IsValid() {
if goSyntax {
p.buf.WriteString(reflect.TypeOf(field).String())
p.buf.WriteString(value.Type().String())
p.buf.Write(nilParenBytes)
} else {
p.buf.Write(nilAngleBytes)
}
} else {
return p.printField(value.Interface(), verb, plus, goSyntax, depth+1)
return p.printValue(value, verb, plus, goSyntax, depth+1)
}
case reflect.Array, reflect.Slice:
// Byte slices are special.
@ -765,11 +822,11 @@ BigSwitch:
for i := range bytes {
bytes[i] = byte(f.Index(i).Uint())
}
p.fmtBytes(bytes, verb, goSyntax, depth, field)
p.fmtBytes(bytes, verb, goSyntax, depth, nil, value)
return verb == 's'
}
if goSyntax {
p.buf.WriteString(reflect.TypeOf(field).String())
p.buf.WriteString(value.Type().String())
p.buf.WriteByte('{')
} else {
p.buf.WriteByte('[')
@ -782,7 +839,7 @@ BigSwitch:
p.buf.WriteByte(' ')
}
}
p.printField(f.Index(i).Interface(), verb, plus, goSyntax, depth+1)
p.printValue(f.Index(i), verb, plus, goSyntax, depth+1)
}
if goSyntax {
p.buf.WriteByte('}')
@ -797,17 +854,17 @@ BigSwitch:
switch a := f.Elem(); a.Kind() {
case reflect.Array, reflect.Slice:
p.buf.WriteByte('&')
p.printField(a.Interface(), verb, plus, goSyntax, depth+1)
p.printValue(a, verb, plus, goSyntax, depth+1)
break BigSwitch
case reflect.Struct:
p.buf.WriteByte('&')
p.printField(a.Interface(), verb, plus, goSyntax, depth+1)
p.printValue(a, verb, plus, goSyntax, depth+1)
break BigSwitch
}
}
if goSyntax {
p.buf.WriteByte('(')
p.buf.WriteString(reflect.TypeOf(field).String())
p.buf.WriteString(value.Type().String())
p.buf.WriteByte(')')
p.buf.WriteByte('(')
if v == 0 {
@ -824,7 +881,7 @@ BigSwitch:
}
p.fmt0x64(uint64(v), true)
case reflect.Chan, reflect.Func, reflect.UnsafePointer:
p.fmtPointer(field, value, verb, goSyntax)
p.fmtPointer(nil, value, verb, goSyntax)
default:
p.unknownType(f)
}

115
src/pkg/reflect/all_test.go
View File

@ -855,13 +855,13 @@ func TestIsNil(t *testing.T) {
func TestInterfaceExtraction(t *testing.T) {
var s struct {
w io.Writer
W io.Writer
}
s.w = os.Stdout
s.W = os.Stdout
v := Indirect(ValueOf(&s)).Field(0).Interface()
if v != s.w.(interface{}) {
t.Error("Interface() on interface: ", v, s.w)
if v != s.W.(interface{}) {
t.Error("Interface() on interface: ", v, s.W)
}
}
@ -1156,18 +1156,18 @@ type D2 struct {
}
type S0 struct {
a, b, c int
A, B, C int
D1
D2
}
type S1 struct {
b int
B int
S0
}
type S2 struct {
a int
A int
*S1
}
@ -1182,36 +1182,36 @@ type S1y struct {
type S3 struct {
S1x
S2
d, e int
D, E int
*S1y
}
type S4 struct {
*S4
a int
A int
}
var fieldTests = []FTest{
{struct{}{}, "", nil, 0},
{struct{}{}, "foo", nil, 0},
{S0{a: 'a'}, "a", []int{0}, 'a'},
{S0{}, "d", nil, 0},
{S1{S0: S0{a: 'a'}}, "a", []int{1, 0}, 'a'},
{S1{b: 'b'}, "b", []int{0}, 'b'},
{struct{}{}, "Foo", nil, 0},
{S0{A: 'a'}, "A", []int{0}, 'a'},
{S0{}, "D", nil, 0},
{S1{S0: S0{A: 'a'}}, "A", []int{1, 0}, 'a'},
{S1{B: 'b'}, "B", []int{0}, 'b'},
{S1{}, "S0", []int{1}, 0},
{S1{S0: S0{c: 'c'}}, "c", []int{1, 2}, 'c'},
{S2{a: 'a'}, "a", []int{0}, 'a'},
{S1{S0: S0{C: 'c'}}, "C", []int{1, 2}, 'c'},
{S2{A: 'a'}, "A", []int{0}, 'a'},
{S2{}, "S1", []int{1}, 0},
{S2{S1: &S1{b: 'b'}}, "b", []int{1, 0}, 'b'},
{S2{S1: &S1{S0: S0{c: 'c'}}}, "c", []int{1, 1, 2}, 'c'},
{S2{}, "d", nil, 0},
{S2{S1: &S1{B: 'b'}}, "B", []int{1, 0}, 'b'},
{S2{S1: &S1{S0: S0{C: 'c'}}}, "C", []int{1, 1, 2}, 'c'},
{S2{}, "D", nil, 0},
{S3{}, "S1", nil, 0},
{S3{S2: S2{a: 'a'}}, "a", []int{1, 0}, 'a'},
{S3{}, "b", nil, 0},
{S3{d: 'd'}, "d", []int{2}, 0},
{S3{e: 'e'}, "e", []int{3}, 'e'},
{S4{a: 'a'}, "a", []int{1}, 'a'},
{S4{}, "b", nil, 0},
{S3{S2: S2{A: 'a'}}, "A", []int{1, 0}, 'a'},
{S3{}, "B", nil, 0},
{S3{D: 'd'}, "D", []int{2}, 0},
{S3{E: 'e'}, "E", []int{3}, 'e'},
{S4{A: 'a'}, "A", []int{1}, 'a'},
{S4{}, "B", nil, 0},
}
func TestFieldByIndex(t *testing.T) {
@ -1508,3 +1508,68 @@ func TestVariadic(t *testing.T) {
t.Errorf("after Fprintf CallSlice: %q != %q", b.String(), "hello 42 world")
}
}
type Private struct {
x int
y **int
}
func (p *Private) m() {
}
type Public struct {
X int
Y **int
}
func (p *Public) M() {
}
func TestUnexported(t *testing.T) {
var pub Public
v := ValueOf(&pub)
isValid(v.Elem().Field(0))
isValid(v.Elem().Field(1))
isValid(v.Elem().FieldByName("X"))
isValid(v.Elem().FieldByName("Y"))
isValid(v.Type().Method(0).Func)
isNonNil(v.Elem().Field(0).Interface())
isNonNil(v.Elem().Field(1).Interface())
isNonNil(v.Elem().FieldByName("X").Interface())
isNonNil(v.Elem().FieldByName("Y").Interface())
isNonNil(v.Type().Method(0).Func.Interface())
var priv Private
v = ValueOf(&priv)
isValid(v.Elem().Field(0))
isValid(v.Elem().Field(1))
isValid(v.Elem().FieldByName("x"))
isValid(v.Elem().FieldByName("y"))
isValid(v.Type().Method(0).Func)
shouldPanic(func() { v.Elem().Field(0).Interface() })
shouldPanic(func() { v.Elem().Field(1).Interface() })
shouldPanic(func() { v.Elem().FieldByName("x").Interface() })
shouldPanic(func() { v.Elem().FieldByName("y").Interface() })
shouldPanic(func() { v.Type().Method(0).Func.Interface() })
}
func shouldPanic(f func()) {
defer func() {
if recover() == nil {
panic("did not panic")
}
}()
f()
}
func isNonNil(x interface{}) {
if x == nil {
panic("nil interface")
}
}
func isValid(v Value) {
if !v.IsValid() {
panic("zero Value")
}
}

2
src/pkg/reflect/deepequal.go
View File

@ -104,7 +104,7 @@ func deepValueEqual(v1, v2 Value, visited map[uintptr]*visit, depth int) (b bool
return true
default:
// Normal equality suffices
return v1.Interface() == v2.Interface()
return valueInterface(v1, false) == valueInterface(v2, false)
}
panic("Not reached")

31
src/pkg/reflect/value.go
View File

@ -841,14 +841,7 @@ func (v Value) CanInterface() bool {
if iv.kind == Invalid {
panic(&ValueError{"reflect.Value.CanInterface", iv.kind})
}
// TODO(rsc): Check flagRO too. Decide what to do about asking for
// interface for a value obtained via an unexported field.
// If the field were of a known type, say chan int or *sync.Mutex,
// the caller could interfere with the data after getting the
// interface. But fmt.Print depends on being able to look.
// Now that reflect is more efficient the special cases in fmt
// might be less important.
return v.InternalMethod == 0
return v.InternalMethod == 0 && iv.flag&flagRO == 0
}
// Interface returns v's value as an interface{}.
@ -856,19 +849,25 @@ func (v Value) CanInterface() bool {
// (as opposed to Type.Method), Interface cannot return an
// interface value, so it panics.
func (v Value) Interface() interface{} {
return v.internal().Interface()
return valueInterface(v, true)
}
func (iv internalValue) Interface() interface{} {
func valueInterface(v Value, safe bool) interface{} {
iv := v.internal()
return iv.valueInterface(safe)
}
func (iv internalValue) valueInterface(safe bool) interface{} {
if iv.method {
panic("reflect.Value.Interface: cannot create interface value for method with bound receiver")
}
/*
if v.flag()&noExport != 0 {
panic("reflect.Value.Interface: cannot return value obtained from unexported struct field")
}
*/
if safe && iv.flag&flagRO != 0 {
// Do not allow access to unexported values via Interface,
// because they might be pointers that should not be
// writable or methods or function that should not be callable.
panic("reflect.Value.Interface: cannot return value obtained from unexported field or method")
}
if iv.kind == Interface {
// Special case: return the element inside the interface.
// Won't recurse further because an interface cannot contain an interface.
@ -1669,7 +1668,7 @@ func convertForAssignment(what string, addr unsafe.Pointer, dst Type, iv interna
if addr == nil {
addr = unsafe.Pointer(new(interface{}))
}
x := iv.Interface()
x := iv.valueInterface(false)
if dst.NumMethod() == 0 {
*(*interface{})(addr) = x
} else {

40
test/interface/fake.go
View File

@ -12,20 +12,20 @@ package main
import "reflect"
type T struct {
f float32
g float32
F float32
G float32
s string
t string
S string
T string
u uint32
v uint32
U uint32
V uint32
w uint32
x uint32
W uint32
X uint32
y uint32
z uint32
Y uint32
Z uint32
}
func add(s, t string) string {
@ -40,16 +40,16 @@ func assert(b bool) {
func main() {
var x T
x.f = 1.0
x.g = x.f
x.s = add("abc", "def")
x.t = add("abc", "def")
x.u = 1
x.v = 2
x.w = 1 << 28
x.x = 2 << 28
x.y = 0x12345678
x.z = x.y
x.F = 1.0
x.G = x.F
x.S = add("abc", "def")
x.T = add("abc", "def")
x.U = 1
x.V = 2
x.W = 1 << 28
x.X = 2 << 28
x.Y = 0x12345678
x.Z = x.Y
// check mem and string
v := reflect.ValueOf(x)