From 52ebadd3569b31ce423d4868ac9aa54a373aa1ad Mon Sep 17 00:00:00 2001 From: Rob Pike Date: Wed, 8 Feb 2012 14:09:20 +1100 Subject: [PATCH] encoding/binary: hide TotalSize The function has a bizarre signature: it was the only public function there that exposed the reflect package. Also, its definition is peculiar and hard to explain. It doesn't merit being exported. This is an API change but really, it should never have been exported and it's certain very few programs will depend on it: it's too weird. Fixes #2846. R=golang-dev, gri, bradfitz CC=golang-dev https://golang.org/cl/5639054 --- doc/go1.html | 99 ++++++++++++++------------ doc/go1.tmpl | 99 ++++++++++++++------------ src/pkg/encoding/binary/binary.go | 10 ++- src/pkg/encoding/binary/binary_test.go | 2 +- 4 files changed, 118 insertions(+), 92 deletions(-) diff --git a/doc/go1.html b/doc/go1.html index 95953dc79b..4191c4ba25 100644 --- a/doc/go1.html +++ b/doc/go1.html @@ -929,6 +929,61 @@ to be implemented in the future. No changes will be needed.

+

The encoding/binary package

+ +

+In Go 1, the binary.TotalSize function is no longer exported. +

+ +

+Updating: +Code that depends on the function will need to be updated. +

+ +

The encoding/xml package

+ +

+In Go 1, the xml package +has been brought closer in design to the other marshaling packages such +as encoding/gob. +

+ +

+The old Parser type is renamed +Decoder and has a new +Decode method. An +Encoder type was also +introduced. +

+ +

+The functions Marshal +and Unmarshal +work with []byte values now. To work with streams, +use the new Encoder +and Decoder types. +

+ +

+When marshaling or unmarshaling values, the format of supported flags in +field tags has changed to be closer to the +json package +(`xml:"name,flag"`). The matching done between field tags, field +names, and the XML attribute and element names is now case-sensitive. +The XMLName field tag, if present, must also match the name +of the XML element being marshaled. +

+ +

+Updating: +Running go fix will update most uses of the package except for some calls to +Unmarshal. Special care must be taken with field tags, +since the fix tool will not update them and if not fixed by hand they will +misbehave silently in some cases. For example, the old +"attr" is now written ",attr" while plain +"attr" remains valid but with a different meaning. +

+

The expvar package

@@ -1575,50 +1630,6 @@ Code that uses the old fields will fail to compile and must be updated by hand. The semantic changes make it difficult for the fix tool to update automatically.

-

The xml package

- -

-In Go 1, the xml package -has been brought closer in design to the other marshaling packages such -as encoding/gob. -

- -

-The old Parser type is renamed -Decoder and has a new -Decode method. An -Encoder type was also -introduced. -

- -

-The functions Marshal -and Unmarshal -work with []byte values now. To work with streams, -use the new Encoder -and Decoder types. -

- -

-When marshaling or unmarshaling values, the format of supported flags in -field tags has changed to be closer to the -json package -(`xml:"name,flag"`). The matching done between field tags, field -names, and the XML attribute and element names is now case-sensitive. -The XMLName field tag, if present, must also match the name -of the XML element being marshaled. -

- -

-Updating: -Running go fix will update most uses of the package except for some calls to -Unmarshal. Special care must be taken with field tags, -since the fix tool will not update them and if not fixed by hand they will -misbehave silently in some cases. For example, the old -"attr" is now written ",attr" while plain -"attr" remains valid but with a different meaning. -

-

The go command

Packaged releases

diff --git a/doc/go1.tmpl b/doc/go1.tmpl index 5400198291..819c71ed38 100644 --- a/doc/go1.tmpl +++ b/doc/go1.tmpl @@ -833,6 +833,61 @@ to be implemented in the future. No changes will be needed.

+

The encoding/binary package

+ +

+In Go 1, the binary.TotalSize function is no longer exported. +

+ +

+Updating: +Code that depends on the function will need to be updated. +

+ +

The encoding/xml package

+ +

+In Go 1, the xml package +has been brought closer in design to the other marshaling packages such +as encoding/gob. +

+ +

+The old Parser type is renamed +Decoder and has a new +Decode method. An +Encoder type was also +introduced. +

+ +

+The functions Marshal +and Unmarshal +work with []byte values now. To work with streams, +use the new Encoder +and Decoder types. +

+ +

+When marshaling or unmarshaling values, the format of supported flags in +field tags has changed to be closer to the +json package +(`xml:"name,flag"`). The matching done between field tags, field +names, and the XML attribute and element names is now case-sensitive. +The XMLName field tag, if present, must also match the name +of the XML element being marshaled. +

+ +

+Updating: +Running go fix will update most uses of the package except for some calls to +Unmarshal. Special care must be taken with field tags, +since the fix tool will not update them and if not fixed by hand they will +misbehave silently in some cases. For example, the old +"attr" is now written ",attr" while plain +"attr" remains valid but with a different meaning. +

+

The expvar package

@@ -1465,50 +1520,6 @@ Code that uses the old fields will fail to compile and must be updated by hand. The semantic changes make it difficult for the fix tool to update automatically.

-

The xml package

- -

-In Go 1, the xml package -has been brought closer in design to the other marshaling packages such -as encoding/gob. -

- -

-The old Parser type is renamed -Decoder and has a new -Decode method. An -Encoder type was also -introduced. -

- -

-The functions Marshal -and Unmarshal -work with []byte values now. To work with streams, -use the new Encoder -and Decoder types. -

- -

-When marshaling or unmarshaling values, the format of supported flags in -field tags has changed to be closer to the -json package -(`xml:"name,flag"`). The matching done between field tags, field -names, and the XML attribute and element names is now case-sensitive. -The XMLName field tag, if present, must also match the name -of the XML element being marshaled. -

- -

-Updating: -Running go fix will update most uses of the package except for some calls to -Unmarshal. Special care must be taken with field tags, -since the fix tool will not update them and if not fixed by hand they will -misbehave silently in some cases. For example, the old -"attr" is now written ",attr" while plain -"attr" remains valid but with a different meaning. -

-

The go command

Packaged releases

diff --git a/src/pkg/encoding/binary/binary.go b/src/pkg/encoding/binary/binary.go index d2f8b1e624..4be83f53bd 100644 --- a/src/pkg/encoding/binary/binary.go +++ b/src/pkg/encoding/binary/binary.go @@ -163,7 +163,7 @@ func Read(r io.Reader, order ByteOrder, data interface{}) error { default: return errors.New("binary.Read: invalid type " + d.Type().String()) } - size := TotalSize(v) + size := dataSize(v) if size < 0 { return errors.New("binary.Read: invalid type " + v.Type().String()) } @@ -242,7 +242,7 @@ func Write(w io.Writer, order ByteOrder, data interface{}) error { return err } v := reflect.Indirect(reflect.ValueOf(data)) - size := TotalSize(v) + size := dataSize(v) if size < 0 { return errors.New("binary.Write: invalid type " + v.Type().String()) } @@ -253,7 +253,11 @@ func Write(w io.Writer, order ByteOrder, data interface{}) error { return err } -func TotalSize(v reflect.Value) int { +// dataSize returns the number of bytes the actual data represented by v occupies in memory. +// For compound structures, it sums the sizes of the elements. Thus, for instance, for a slice +// it returns the length of the slice times the element size and does not count the memory +// occupied by the header. +func dataSize(v reflect.Value) int { if v.Kind() == reflect.Slice { elem := sizeof(v.Type().Elem()) if elem < 0 { diff --git a/src/pkg/encoding/binary/binary_test.go b/src/pkg/encoding/binary/binary_test.go index 3e7057ea22..ff361b7e37 100644 --- a/src/pkg/encoding/binary/binary_test.go +++ b/src/pkg/encoding/binary/binary_test.go @@ -187,7 +187,7 @@ func BenchmarkReadStruct(b *testing.B) { bsr := &byteSliceReader{} var buf bytes.Buffer Write(&buf, BigEndian, &s) - n := TotalSize(reflect.ValueOf(s)) + n := dataSize(reflect.ValueOf(s)) b.SetBytes(int64(n)) t := s b.ResetTimer() -- 2.52.0