use ergochat/irc-go instead of goshuirc/irc-go

vendor/github.com/ergochat/irc-go/ircutils/doc.go

@@ -0,0 +1,9 @@
+// written by Daniel Oaks <daniel@danieloaks.net>
+// released under the ISC license
+
+/*
+Package ircutils provides small, useful utility functions and classes.
+
+This package is in an alpha stage.
+*/
+package ircutils

vendor/github.com/ergochat/irc-go/ircutils/hostnames.go

@@ -0,0 +1,41 @@
+// written by Daniel Oaks <daniel@danieloaks.net>
+// released under the ISC license
+
+package ircutils
+
+import "strings"
+
+var allowedHostnameChars = "abcdefghijklmnopqrstuvwxyz1234567890-."
+
+// HostnameIsValid provides a way for servers to check whether a looked-up client
+// hostname is valid (see InspIRCd #1033 for why this is required).
+//
+// This function shouldn't be called by clients since they don't need to validate
+// hostnames for IRC use, just by servers that need to confirm hostnames of incoming
+// clients.
+//
+// In addition to this function, servers should impose their own limits on max
+// hostname length -- this function limits it to 200 but most servers will probably
+// want to make it smaller than that.
+func HostnameIsValid(hostname string) bool {
+	// IRC hostnames specifically require a period, rough limit of 200 chars
+	if !strings.Contains(hostname, ".") || len(hostname) < 1 || len(hostname) > 200 {
+		return false
+	}
+
+	// ensure each part of hostname is valid
+	for _, part := range strings.Split(hostname, ".") {
+		if len(part) < 1 || len(part) > 63 || strings.HasPrefix(part, "-") || strings.HasSuffix(part, "-") {
+			return false
+		}
+	}
+
+	// ensure all chars of hostname are valid
+	for _, char := range strings.Split(strings.ToLower(hostname), "") {
+		if !strings.Contains(allowedHostnameChars, char) {
+			return false
+		}
+	}
+
+	return true
+}

vendor/github.com/ergochat/irc-go/ircutils/unicode.go

@@ -0,0 +1,62 @@
+// Copyright (c) 2021 Shivaram Lingamneni
+// Released under the MIT License
+
+package ircutils
+
+import (
+	"strings"
+	"unicode"
+	"unicode/utf8"
+)
+
+// truncate a message, taking care not to make valid UTF8 into invalid UTF8
+func TruncateUTF8Safe(message string, byteLimit int) (result string) {
+	if len(message) <= byteLimit {
+		return message
+	}
+	message = message[:byteLimit]
+	for i := 0; i < (utf8.UTFMax - 1); i++ {
+		r, n := utf8.DecodeLastRuneInString(message)
+		if r == utf8.RuneError && n <= 1 {
+			message = message[:len(message)-1]
+		} else {
+			break
+		}
+	}
+	return message
+}
+
+// Sanitizes human-readable text to make it safe for IRC;
+// assumes UTF-8 and uses the replacement character where
+// applicable.
+func SanitizeText(message string, byteLimit int) (result string) {
+	var buf strings.Builder
+
+	for _, r := range message {
+		if r == '\x00' || r == '\r' {
+			continue
+		} else if r == '\n' {
+			if buf.Len()+2 <= byteLimit {
+				buf.WriteString("  ")
+				continue
+			} else {
+				break
+			}
+		} else if unicode.IsSpace(r) {
+			if buf.Len()+1 <= byteLimit {
+				buf.WriteString(" ")
+			} else {
+				break
+			}
+		} else {
+			rLen := utf8.RuneLen(r)
+			if buf.Len()+rLen <= byteLimit {
+				buf.WriteRune(r)
+			} else {
+				break
+			}
+		}
+	}
+
+	return buf.String()
+}

vendor/github.com/ergochat/irc-go/ircutils/userhost.go

@@ -0,0 +1,56 @@
+// written by Daniel Oaks <daniel@danieloaks.net>
+// released under the ISC license
+
+package ircutils
+
+import "strings"
+
+// UserHost holds a username+host combination
+type UserHost struct {
+	Nick string
+	User string
+	Host string
+}
+
+// ParseUserhost takes a userhost string and returns a UserHost instance.
+func ParseUserhost(userhost string) UserHost {
+	var uh UserHost
+
+	if len(userhost) == 0 {
+		return uh
+	}
+
+	if strings.Contains(userhost, "!") {
+		usersplit := strings.SplitN(userhost, "!", 2)
+		var rest string
+		if len(usersplit) == 2 {
+			uh.Nick = usersplit[0]
+			rest = usersplit[1]
+		} else {
+			rest = usersplit[0]
+		}
+
+		hostsplit := strings.SplitN(rest, "@", 2)
+		if len(hostsplit) == 2 {
+			uh.User = hostsplit[0]
+			uh.Host = hostsplit[1]
+		} else {
+			uh.User = hostsplit[0]
+		}
+	} else {
+		hostsplit := strings.SplitN(userhost, "@", 2)
+		if len(hostsplit) == 2 {
+			uh.Nick = hostsplit[0]
+			uh.Host = hostsplit[1]
+		} else {
+			uh.User = hostsplit[0]
+		}
+	}
+
+	return uh
+}
+
+// // Canonical returns the canonical string representation of the userhost.
+// func (uh *UserHost) Canonical() string {
+// 	return ""
+// }