Changeset 139 in code for trunk/irc.go

Timestamp:

Mar 25, 2020, 8:40:08 AM (5 years ago)

Author:

delthas

Message:

Add MODE arguments support

• Add RPL_ISUPPORT support with CHANMODES, CHANTYPES, PREFIX parsing
• Add support for channel mode state with mode arguments
• Add upstream support for RPL_UMODEIS, RPL_CHANNELMODEIS
• Request channel MODE on upstream channel JOIN
• Use sane default channel mode and channel mode types

File:

• trunk/irc.go (modified) (4 diffs)

trunk/irc.go

@@ -16 +16 @@
 )
 
-type modeSet string
+type userModes string
 
-func (ms modeSet) Has(c byte) bool {
+func (ms userModes) Has(c byte) bool {
         return strings.IndexByte(string(ms), c) >= 0
 }
 
-func (ms *modeSet) Add(c byte) {
+func (ms *userModes) Add(c byte) {
         if !ms.Has(c) {
-                *ms += modeSet(c)
+                *ms += userModes(c)
         }
 }
 
-func (ms *modeSet) Del(c byte) {
+func (ms *userModes) Del(c byte) {
         i := strings.IndexByte(string(*ms), c)
         if i >= 0 {
@@ -35 +35 @@
 }
 
-func (ms *modeSet) Apply(s string) error {
+func (ms *userModes) Apply(s string) error {
         var plusMinus byte
         for i := 0; i < len(s); i++ {
@@ -54 +54 @@
         return nil
 }
+
+type channelModeType byte
+
+// standard channel mode types, as explained in https://modern.ircdocs.horse/#mode-message
+const (
+        // modes that add or remove an address to or from a list
+        modeTypeA channelModeType = iota
+        // modes that change a setting on a channel, and must always have a parameter
+        modeTypeB
+        // modes that change a setting on a channel, and must have a parameter when being set, and no parameter when being unset
+        modeTypeC
+        // modes that change a setting on a channel, and must not have a parameter
+        modeTypeD
+)
+
+var stdChannelModes = map[byte]channelModeType{
+        'b': modeTypeA, // ban list
+        'e': modeTypeA, // ban exception list
+        'I': modeTypeA, // invite exception list
+        'k': modeTypeB, // channel key
+        'l': modeTypeC, // channel user limit
+        'i': modeTypeD, // channel is invite-only
+        'm': modeTypeD, // channel is moderated
+        'n': modeTypeD, // channel has no external messages
+        's': modeTypeD, // channel is secret
+        't': modeTypeD, // channel has protected topic
+}
+
+type channelModes map[byte]string
+
+func (cm channelModes) Apply(modeTypes map[byte]channelModeType, modeStr string, arguments ...string) error {
+        nextArgument := 0
+        var plusMinus byte
+        for i := 0; i < len(modeStr); i++ {
+                mode := modeStr[i]
+                if mode == '+' || mode == '-' {
+                        plusMinus = mode
+                        continue
+                }
+                if plusMinus != '+' && plusMinus != '-' {
+                        return fmt.Errorf("malformed modestring %q: missing plus/minus", modeStr)
+                }
+
+                mt, ok := modeTypes[mode]
+                if !ok {
+                        continue
+                }
+                if mt == modeTypeB || (mt == modeTypeC && plusMinus == '+') {
+                        if plusMinus == '+' {
+                                var argument string
+                                // some sentitive arguments (such as channel keys) can be omitted for privacy
+                                // (this will only happen for RPL_CHANNELMODEIS, never for MODE messages)
+                                if nextArgument < len(arguments) {
+                                        argument = arguments[nextArgument]
+                                }
+                                cm[mode] = argument
+                        } else {
+                                delete(cm, mode)
+                        }
+                        nextArgument++
+                } else if mt == modeTypeC || mt == modeTypeD {
+                        if plusMinus == '+' {
+                                cm[mode] = ""
+                        } else {
+                                delete(cm, mode)
+                        }
+                }
+        }
+        return nil
+}
+
+func (cm channelModes) Format() (modeString string, parameters []string) {
+        var modesWithValues strings.Builder
+        var modesWithoutValues strings.Builder
+        parameters = make([]string, 0, 16)
+        for mode, value := range cm {
+                if value != "" {
+                        modesWithValues.WriteString(string(mode))
+                        parameters = append(parameters, value)
+                } else {
+                        modesWithoutValues.WriteString(string(mode))
+                }
+        }
+        modeString = "+" + modesWithValues.String() + modesWithoutValues.String()
+        return
+}
+
+const stdChannelTypes = "#&+!"
 
 type channelStatus byte
@@ -75 +163 @@
 }
 
-type membership byte
+type membership struct {
+        Mode   byte
+        Prefix byte
+}
 
-const (
-        membershipFounder   membership = '~'
-        membershipProtected membership = '&'
-        membershipOperator  membership = '@'
-        membershipHalfOp    membership = '%'
-        membershipVoice     membership = '+'
-)
+var stdMemberships = []membership{
+        {'q', '~'}, // founder
+        {'a', '&'}, // protected
+        {'o', '@'}, // operator
+        {'h', '%'}, // halfop
+        {'v', '+'}, // voice
+}
 
-const stdMembershipPrefixes = "~&@%+"
-
-func (m membership) String() string {
-        if m == 0 {
+func (m *membership) String() string {
+        if m == nil {
                 return ""
         }
-        return string(m)
-}
-
-func parseMembershipPrefix(s string) (prefix membership, nick string) {
-        // TODO: any prefix from PREFIX RPL_ISUPPORT
-        if strings.IndexByte(stdMembershipPrefixes, s[0]) >= 0 {
-                return membership(s[0]), s[1:]
-        } else {
-                return 0, s
-        }
+        return string(m.Prefix)
 }