203 lines
4.4 KiB
Go
203 lines
4.4 KiB
Go
// Copyright 2016-2017 Liam Stanley <me@liamstanley.io>. All rights reserved.
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// Use of this source code is governed by the MIT license that can be
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// found in the LICENSE file.
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package girc
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import (
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"bytes"
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"fmt"
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"io"
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"strings"
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)
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const (
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prefixTag byte = 0x40 // @
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prefixTagValue byte = 0x3D // =
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tagSeparator byte = 0x3B // ;
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maxTagLength int = 511 // 510 + @ and " " (space), though space usually not included.
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)
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// Tags represents the key-value pairs in IRCv3 message tags. The map contains
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// the encoded message-tag values. If the tag is present, it may still be
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// empty. See Tags.Get() and Tags.Set() for use with getting/setting
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// information within the tags.
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//
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// Note that retrieving and setting tags are not concurrent safe. If this is
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// necessary, you will need to implement it yourself.
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type Tags map[string]string
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// ParseTags parses out the key-value map of tags. raw should only be the tag
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// data, not a full message. For example:
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// @aaa=bbb;ccc;example.com/ddd=eee
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// NOT:
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// @aaa=bbb;ccc;example.com/ddd=eee :nick!ident@host.com PRIVMSG me :Hello
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func ParseTags(raw string) (t Tags) {
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t = make(Tags)
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parts := strings.Split(raw, string(tagSeparator))
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var hasValue int
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for i := 0; i < len(parts); i++ {
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hasValue = strings.IndexByte(parts[i], prefixTagValue)
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if hasValue < 1 {
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// The tag doesn't contain a value.
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t[parts[i]] = ""
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continue
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}
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// May have equals sign and no value as well.
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if len(parts[i]) < hasValue+1 {
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t[parts[i]] = ""
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continue
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}
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t[parts[i][:hasValue]] = parts[i][hasValue+1:]
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continue
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}
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return t
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}
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// Len determines the length of the string representation of this tag map.
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func (t Tags) Len() (length int) {
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return len(t.String())
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}
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// Count finds how many total tags that there are.
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func (t Tags) Count() int {
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return len(t)
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}
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// Bytes returns a []byte representation of this tag map.
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func (t Tags) Bytes() []byte {
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max := len(t)
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if max == 0 {
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return nil
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}
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buffer := new(bytes.Buffer)
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var current int
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for tagName, tagValue := range t {
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// Trim at max allowed chars.
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if (buffer.Len() + len(tagName) + len(tagValue) + 2) > maxTagLength {
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return buffer.Bytes()
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}
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buffer.WriteString(tagName)
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// Write the value as necessary.
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if len(tagValue) > 0 {
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buffer.WriteByte(prefixTagValue)
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buffer.WriteString(tagValue)
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}
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// add the separator ";" between tags.
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if current <= max {
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buffer.WriteByte(tagSeparator)
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}
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current++
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}
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return buffer.Bytes()
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}
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// String returns a string representation of this tag map.
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func (t Tags) String() string {
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return string(t.Bytes())
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}
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func (t Tags) writeTo(w io.Writer) (n int, err error) {
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b := t.Bytes()
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if len(b) == 0 {
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return n, err
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}
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n, err = w.Write(b)
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if err != nil {
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return n, err
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}
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var j int
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j, err = w.Write([]byte{eventSpace})
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n += j
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return n, err
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}
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// tagDecode are encoded -> decoded pairs for replacement to decode.
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var tagDecode = []string{
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"\\:", ";",
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"\\s", " ",
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"\\\\", "\\",
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"\\r", "\r",
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"\\n", "\n",
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}
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var tagDecoder = strings.NewReplacer(tagDecode...)
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// tagEncode are decoded -> encoded pairs for replacement to decode.
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var tagEncode = []string{
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";", "\\:",
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" ", "\\s",
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"\\", "\\\\",
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"\r", "\\r",
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"\n", "\\n",
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}
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var tagEncoder = strings.NewReplacer(tagEncode...)
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// Get returns the unescaped value of given tag key. Note that this is not
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// concurrent safe.
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func (t Tags) Get(key string) (tag string, success bool) {
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if _, ok := t[key]; ok {
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tag = tagDecoder.Replace(t[key])
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success = true
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}
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return tag, success
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}
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// Set escapes given value and saves it as the value for given key. Note that
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// this is not concurrent safe.
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func (t Tags) Set(key, value string) error {
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if !validTag(key) {
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return fmt.Errorf("tag %q is invalid", key)
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}
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value = tagEncoder.Replace(value)
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// Check to make sure it's not too long here.
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if (t.Len() + len(key) + len(value) + 2) > maxTagLength {
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return fmt.Errorf("unable to set tag %q [value %q]: tags too long for message", key, value)
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}
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t[key] = value
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return nil
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}
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// Remove deletes the tag frwom the tag map.
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func (t Tags) Remove(key string) (success bool) {
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if _, success = t[key]; success {
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delete(t, key)
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}
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return success
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}
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func validTag(name string) bool {
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if len(name) < 1 {
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return false
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}
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for i := 0; i < len(name); i++ {
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// A-Z, a-z, 0-9, -/._
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if (name[i] < 0x41 || name[i] > 0x5A) && (name[i] < 0x61 || name[i] > 0x7A) && (name[i] < 0x2D || name[i] > 0x39) && name[i] != 0x5F {
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return false
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}
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}
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return true
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}
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