92 lines
2.5 KiB
Go
92 lines
2.5 KiB
Go
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// Copyright 2013 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package packet
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import (
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"bytes"
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"image"
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"image/jpeg"
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"io"
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"io/ioutil"
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)
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const UserAttrImageSubpacket = 1
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// UserAttribute is capable of storing other types of data about a user
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// beyond name, email and a text comment. In practice, user attributes are typically used
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// to store a signed thumbnail photo JPEG image of the user.
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// See RFC 4880, section 5.12.
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type UserAttribute struct {
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Contents []*OpaqueSubpacket
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}
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// NewUserAttributePhoto creates a user attribute packet
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// containing the given images.
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func NewUserAttributePhoto(photos ...image.Image) (uat *UserAttribute, err error) {
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uat = new(UserAttribute)
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for _, photo := range photos {
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var buf bytes.Buffer
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// RFC 4880, Section 5.12.1.
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data := []byte{
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0x10, 0x00, // Little-endian image header length (16 bytes)
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0x01, // Image header version 1
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0x01, // JPEG
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0, 0, 0, 0, // 12 reserved octets, must be all zero.
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0, 0, 0, 0,
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0, 0, 0, 0}
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if _, err = buf.Write(data); err != nil {
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return
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}
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if err = jpeg.Encode(&buf, photo, nil); err != nil {
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return
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}
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uat.Contents = append(uat.Contents, &OpaqueSubpacket{
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SubType: UserAttrImageSubpacket,
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Contents: buf.Bytes()})
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}
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return
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}
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// NewUserAttribute creates a new user attribute packet containing the given subpackets.
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func NewUserAttribute(contents ...*OpaqueSubpacket) *UserAttribute {
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return &UserAttribute{Contents: contents}
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}
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func (uat *UserAttribute) parse(r io.Reader) (err error) {
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// RFC 4880, section 5.13
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b, err := ioutil.ReadAll(r)
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if err != nil {
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return
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}
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uat.Contents, err = OpaqueSubpackets(b)
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return
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}
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// Serialize marshals the user attribute to w in the form of an OpenPGP packet, including
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// header.
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func (uat *UserAttribute) Serialize(w io.Writer) (err error) {
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var buf bytes.Buffer
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for _, sp := range uat.Contents {
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sp.Serialize(&buf)
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}
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if err = serializeHeader(w, packetTypeUserAttribute, buf.Len()); err != nil {
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return err
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}
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_, err = w.Write(buf.Bytes())
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return
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}
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// ImageData returns zero or more byte slices, each containing
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// JPEG File Interchange Format (JFIF), for each photo in the
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// the user attribute packet.
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func (uat *UserAttribute) ImageData() (imageData [][]byte) {
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for _, sp := range uat.Contents {
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if sp.SubType == UserAttrImageSubpacket && len(sp.Contents) > 16 {
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imageData = append(imageData, sp.Contents[16:])
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}
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}
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return
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}
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