Changeset 478 in code for trunk/irc.go

Timestamp:

Mar 24, 2021, 5:15:52 PM (4 years ago)

Author:

hubert

Message:

Implement casemapping

TL;DR: supports for casemapping, now logs are saved in
casemapped/canonical/tolower form
(eg. in the #channel directory instead of #Channel... or something)

What is casemapping?

see <​https://modern.ircdocs.horse/#casemapping-parameter>

Casemapping and multi-upstream

Since each upstream does not necessarily use the same casemapping, and
since casemappings cannot coexist [0],

1. soju must also update the database accordingly to upstreams' casemapping, otherwise it will end up inconsistent,
2. soju must "normalize" entity names and expose only one casemapping that is a subset of all supported casemappings (here, ascii).

[0] On some upstreams, "emersion[m]" and "emersion{m}" refer to the same
user (upstreams that advertise rfc1459 for example), while on others
(upstreams that advertise ascii) they don't.

Once upstream's casemapping is known (default to rfc1459), entity names
in map keys are made into casemapped form, for upstreamConn,
upstreamChannel and network.

downstreamConn advertises "CASEMAPPING=ascii", and always casemap map
keys with ascii.

Some functions require the caller to casemap their argument (to avoid
needless calls to casemapping functions).

Message forwarding and casemapping

downstream message handling (joins and parts basically):
When relaying entity names from downstreams to upstreams, soju uses the
upstream casemapping, in order to not get in the way of the user. This
does not brings any issue, as long as soju replies with the ascii
casemapping in mind (solves point 1.).

marshalEntity/marshalUserPrefix:
When relaying entity names from upstreams with non-ascii casemappings,
soju *partially* casemap them: it only change the case of characters
which are not ascii letters. ASCII case is thus kept intact, while
special symbols like []{} are the same every time soju sends them to
downstreams (solves point 2.).

Casemapping changes

Casemapping changes are not fully supported by this patch and will
result in loss of history. This is a limitation of the protocol and
should be solved by the RENAME spec.

File:

• trunk/irc.go (modified) (2 diffs)

trunk/irc.go

@@ -122 +122 @@
                                 }
                                 member := arguments[nextArgument]
-                                if _, ok := ch.Members[member]; ok {
+                                m := ch.Members.Value(member)
+                                if m != nil {
                                         if plusMinus == '+' {
-                                                ch.Members[member].Add(ch.conn.availableMemberships, membership)
+                                                m.Add(ch.conn.availableMemberships, membership)
                                         } else {
                                                 // TODO: for upstreams without multi-prefix, query the user modes again
-                                                ch.Members[member].Remove(membership)
+                                                m.Remove(membership)
                                         }
                                 }
@@ -419 +420 @@
         return cmd, params, true
 }
+
+type casemapping func(string) string
+
+func casemapNone(name string) string {
+        return name
+}
+
+// CasemapASCII of name is the canonical representation of name according to the
+// ascii casemapping.
+func casemapASCII(name string) string {
+        var sb strings.Builder
+        sb.Grow(len(name))
+        for _, r := range name {
+                if 'A' <= r && r <= 'Z' {
+                        r += 'a' - 'A'
+                }
+                sb.WriteRune(r)
+        }
+        return sb.String()
+}
+
+// casemapRFC1459 of name is the canonical representation of name according to the
+// rfc1459 casemapping.
+func casemapRFC1459(name string) string {
+        var sb strings.Builder
+        sb.Grow(len(name))
+        for _, r := range name {
+                if 'A' <= r && r <= 'Z' {
+                        r += 'a' - 'A'
+                } else if r == '{' {
+                        r = '['
+                } else if r == '}' {
+                        r = ']'
+                } else if r == '\\' {
+                        r = '|'
+                } else if r == '~' {
+                        r = '^'
+                }
+                sb.WriteRune(r)
+        }
+        return sb.String()
+}
+
+// casemapRFC1459Strict of name is the canonical representation of name
+// according to the rfc1459-strict casemapping.
+func casemapRFC1459Strict(name string) string {
+        var sb strings.Builder
+        sb.Grow(len(name))
+        for _, r := range name {
+                if 'A' <= r && r <= 'Z' {
+                        r += 'a' - 'A'
+                } else if r == '{' {
+                        r = '['
+                } else if r == '}' {
+                        r = ']'
+                } else if r == '\\' {
+                        r = '|'
+                }
+                sb.WriteRune(r)
+        }
+        return sb.String()
+}
+
+func parseCasemappingToken(tokenValue string) (casemap casemapping, ok bool) {
+        switch tokenValue {
+        case "ascii":
+                casemap = casemapASCII
+        case "rfc1459":
+                casemap = casemapRFC1459
+        case "rfc1459-strict":
+                casemap = casemapRFC1459Strict
+        default:
+                return nil, false
+        }
+        return casemap, true
+}
+
+func partialCasemap(higher casemapping, name string) string {
+        nameFullyCM := higher(name)
+        var sb strings.Builder
+        sb.Grow(len(name))
+        for i, r := range nameFullyCM {
+                if 'a' <= r && r <= 'z' {
+                        r = rune(name[i])
+                }
+                sb.WriteRune(r)
+        }
+        return sb.String()
+}
+
+type casemapMap struct {
+        innerMap map[string]casemapEntry
+        casemap  casemapping
+}
+
+type casemapEntry struct {
+        originalKey string
+        value       interface{}
+}
+
+func newCasemapMap(size int) casemapMap {
+        return casemapMap{
+                innerMap: make(map[string]casemapEntry, size),
+                casemap:  casemapNone,
+        }
+}
+
+func (cm *casemapMap) OriginalKey(name string) (key string, ok bool) {
+        entry, ok := cm.innerMap[cm.casemap(name)]
+        if !ok {
+                return "", false
+        }
+        return entry.originalKey, true
+}
+
+func (cm *casemapMap) Has(name string) bool {
+        _, ok := cm.innerMap[cm.casemap(name)]
+        return ok
+}
+
+func (cm *casemapMap) Len() int {
+        return len(cm.innerMap)
+}
+
+func (cm *casemapMap) SetValue(name string, value interface{}) {
+        nameCM := cm.casemap(name)
+        entry, ok := cm.innerMap[nameCM]
+        if !ok {
+                cm.innerMap[nameCM] = casemapEntry{
+                        originalKey: name,
+                        value:       value,
+                }
+                return
+        }
+        entry.value = value
+        cm.innerMap[nameCM] = entry
+}
+
+func (cm *casemapMap) Delete(name string) {
+        delete(cm.innerMap, cm.casemap(name))
+}
+
+func (cm *casemapMap) SetCasemapping(newCasemap casemapping) {
+        cm.casemap = newCasemap
+        newInnerMap := make(map[string]casemapEntry, len(cm.innerMap))
+        for _, entry := range cm.innerMap {
+                newInnerMap[cm.casemap(entry.originalKey)] = entry
+        }
+        cm.innerMap = newInnerMap
+}
+
+type upstreamChannelCasemapMap struct{ casemapMap }
+
+func (cm *upstreamChannelCasemapMap) Value(name string) *upstreamChannel {
+        entry, ok := cm.innerMap[cm.casemap(name)]
+        if !ok {
+                return nil
+        }
+        return entry.value.(*upstreamChannel)
+}
+
+type channelCasemapMap struct{ casemapMap }
+
+func (cm *channelCasemapMap) Value(name string) *Channel {
+        entry, ok := cm.innerMap[cm.casemap(name)]
+        if !ok {
+                return nil
+        }
+        return entry.value.(*Channel)
+}
+
+type membershipsCasemapMap struct{ casemapMap }
+
+func (cm *membershipsCasemapMap) Value(name string) *memberships {
+        entry, ok := cm.innerMap[cm.casemap(name)]
+        if !ok {
+                return nil
+        }
+        return entry.value.(*memberships)
+}
+
+type mapStringStringCasemapMap struct{ casemapMap }
+
+func (cm *mapStringStringCasemapMap) Value(name string) map[string]string {
+        entry, ok := cm.innerMap[cm.casemap(name)]
+        if !ok {
+                return nil
+        }
+        return entry.value.(map[string]string)
+}