negotiate explicitly registered IRC capabilities

(cherry picked from commit c630730a1d)

docs/plugin-api-additions/caps.md

@@ -0,0 +1,35 @@
+# Script-supported capabilities
+
+`register_capability(name, userdata=None, connection_id=None)` returns a normal
+hook handle. Register before connecting/reconnecting. Core requests the name only
+if advertised in CAP LS or CAP NEW. Existing built-in requests remain enabled;
+SASL and STS registration is rejected so scripts cannot change authentication or
+transport policy through this API. None/-1 means any connection (zero is a valid
+connection ID). Names are lowercase ASCII alphanumerics plus - . / _, 1-200 bytes.
+Duplicate registrations do not duplicate requests for an advertised token.
+
+`unhook(handle)` or script/plugin unload removes future request ownership. It
+intentionally does not disable a capability already acknowledged on a live
+connection, because another plugin/core may depend on it. Registering after CAP
+LS does not retrospectively negotiate an already-advertised capability: reconnect
+or wait for CAP NEW. Core retains ownership of CAP END; this API does not extend
+SASL waiting or delay registration awaiting plugin-only CAP ACKs.
+
+`hook_capability(name, callback, userdata=None, priority=PRI_NORM)` independently
+observes negotiation through existing raw CAP hooks. Callback receives
+`(CapabilityEvent, userdata)` with name, subcommand, value, enabled, context and
+connection_id. LS/NEW mean advertised (`enabled=None`), ACK/LIST mean enabled
+(unless a negative ACK), NAK means rejected and DEL means removed. Callback
+returns are ignored so this observer cannot eat core negotiation. Existing raw
+hooks may still eat CAP before this hook according to their normal priorities.
+
+C: `zoitechat_register_capability(ph, name, flags, connection_id, userdata)`;
+flags=0, ID=-1 for any. Check get_info("api_plugin_caps") for "1" before using
+the appended Windows slot. Use existing server CAP hooks for notifications.
+Requests are split at complete token boundaries within the existing wire limit.
+
+```python
+registration = zoitechat.register_capability('draft/example')
+zoitechat.hook_capability('draft/example', lambda event, data:
+                         event.context.prnt('{}: {}'.format(event.subcommand, event.enabled)))
+```

docs/plugin-api-additions/contexts.md

@@ -1,24 +0,0 @@
-# Connection and context navigation
-
-`get_connections()` returns one Connection snapshot per live connection:
-`id`, `network`, `server`, `context`. Connection IDs distinguish simultaneous
-connections with identical names. Prefer its server-tab context where present.
-`get_connection(context=None)` finds the owner of a live context.
-
-`get_contexts(connection_id=None, types=None)` lists live contexts, optionally
-filtered by connection ID (or a Connection object) and session types: server=1,
-channel=2, query=3. `connection.contexts(types=None)` is a convenience method.
-`find_context_by_id(connection_id, channel=None)` / `connection.find(channel)`
-resolve using that connection's IRC comparator; no channel selects the server tab.
-Missing/closed contexts return None. Existing find_context() remains unchanged.
-
-These helpers use the existing channels list's ID/context fields, so no new C
-context ABI is needed. Snapshots are not persistent IDs across client restarts;
-refresh them after closing/recreating connections. Always check Context.set()
-when explicitly selecting a context that might have closed.
-
-```python
-connection = zoitechat.get_connection()
-for context in connection.contexts(types=(2,)):
-    context.prnt('A channel on this exact connection')
-```

plugins/python/_zoitechat_caps.py

@@ -0,0 +1,64 @@
+"""Script-owned capability requests and structured negotiation observations."""
+from collections import namedtuple
+import operator
+import _zoitechat as api
+from _zoitechat_embedded import ffi, lib
+
+__all__ = ['CapabilityEvent', 'register_capability', 'hook_capability']
+CapabilityEvent = namedtuple('CapabilityEvent',
+                            'name subcommand value enabled context connection_id')
+
+
+def register_capability(name, userdata=None, connection_id=None):
+    """Request an advertised capability on next negotiation; unhook releases ownership."""
+    connection_id = -1 if connection_id is None else operator.index(connection_id)
+    if connection_id < -1 or connection_id > 2147483647:
+        raise ValueError('connection_id must fit the C API; -1 means any')
+    plugin = api.__get_current_plugin()
+    hook = plugin.add_hook(None, userdata)
+    handle = lib.zoitechat_register_capability(lib.ph, name.encode(), 0,
+                                              connection_id, hook.handle)
+    if handle == ffi.NULL:
+        hook.is_unload = True
+        plugin.remove_hook(id(hook))
+        raise ValueError('invalid capability name, reserved capability or connection ID')
+    hook.zoitechat_hook = handle
+    return id(hook)
+
+
+def hook_capability(name, callback, userdata=None, priority=api.PRI_NORM):
+    """Observe LS/NEW/ACK/NAK/DEL/LIST; this hook does not itself request the capability."""
+    if not callable(callback):
+        raise TypeError('callback must be callable')
+
+    def dispatch(word, word_eol, data):
+        if not word_eol:
+            return api.EAT_NONE
+        line = word_eol[0]
+        if line.startswith(':'):
+            unused, separator, line = line.partition(' ')
+        parts = line.split(' ', 3)
+        if len(parts) != 4 or parts[0].upper() != 'CAP':
+            return api.EAT_NONE
+        subcommand, tokens = parts[2].upper(), parts[3]
+        if subcommand not in ('LS', 'NEW', 'ACK', 'NAK', 'DEL', 'LIST'):
+            return api.EAT_NONE
+        if tokens.startswith('* '):
+            tokens = tokens[2:]
+        tokens = tokens.lstrip(':')
+        for token in tokens.split():
+            negative = token.startswith('-')
+            cap, equals, value = token.lstrip('-').partition('=')
+            if cap != name:
+                continue
+            enabled = None
+            if subcommand in ('ACK', 'LIST'):
+                enabled = not negative
+            elif subcommand in ('DEL', 'NAK'):
+                enabled = False
+            event = CapabilityEvent(cap, subcommand, value if equals else None,
+                                    enabled, api.get_context(), api.get_prefs('id'))
+            callback(event, data)
+        return api.EAT_NONE  # observing CAP must not suppress core negotiation
+
+    return api.hook_server('CAP', dispatch, userdata, priority)

plugins/python/_zoitechat_contexts.py

@@ -1,75 +0,0 @@
-"""Navigate live connections by ID instead of ambiguous server/network names."""
-from collections import namedtuple
-import operator
-import _zoitechat as api
-
-__all__ = ['Connection', 'get_connections', 'get_connection', 'get_contexts',
-           'find_context_by_id']
-
-
-class Connection(namedtuple('_Connection', 'id network server context')):
-    __slots__ = ()
-
-    def contexts(self, types=None):
-        return get_contexts(self.id, types)
-
-    def find(self, channel=None):
-        return find_context_by_id(self.id, channel)
-
-
-def _id(connection):
-    return operator.index(connection.id if isinstance(connection, Connection) else connection)
-
-
-def get_connections():
-    """Return one snapshot per live connection, including disconnected ones."""
-    entries = api.get_list('channels')
-    by_id = {}
-    order = []
-    for entry in entries:
-        if entry.id not in by_id:
-            order.append(entry.id)
-        if entry.id not in by_id or entry.type == 1:
-            by_id[entry.id] = Connection(entry.id, entry.network, entry.server,
-                                         entry.context)
-    return [by_id[connection_id] for connection_id in order]
-
-
-def get_connection(context=None):
-    """Find the owning connection of a Context; return None when it has closed."""
-    context = context or api.get_context()
-    for entry in api.get_list('channels'):
-        if entry.context == context:
-            for connection in get_connections():
-                if connection.id == entry.id:
-                    return connection
-    return None
-
-
-def get_contexts(connection_id=None, types=None):
-    """Return contexts, optionally restricted to a connection and session types."""
-    if connection_id is not None:
-        connection_id = _id(connection_id)
-    if types is not None:
-        types = frozenset(types)
-    return [entry.context for entry in api.get_list('channels')
-            if (connection_id is None or entry.id == connection_id)
-            and (types is None or entry.type in types)]
-
-
-def find_context_by_id(connection_id, channel=None):
-    """Resolve a live context on exactly one connection; None selects its server tab."""
-    connection_id = _id(connection_id)
-    previous = api.get_context()
-    try:
-        for entry in api.get_list('channels'):
-            if entry.id != connection_id:
-                continue
-            if channel is None:
-                if entry.type == 1:
-                    return entry.context
-            elif entry.context.set() and api.nickcmp(entry.channel, channel) == 0:
-                return entry.context
-    finally:
-        previous.set()
-    return None

src/common/inbound.c

@@ -41,6 +41,8 @@
 #include "network.h"
 #include "notify.h"
 #include "outbound.h"
+#include <gmodule.h>
+#include "plugin.h"
 #include "inbound.h"
 #include "server.h"
 #include "servlist.h"
@@ -1980,6 +1982,22 @@ inbound_cap_ack (server *serv, char *nick, char *extensions,
 	inbound_toggle_caps (serv, extensions, TRUE);
 }
 
+/* Keep CAP REQ tokens intact and below the existing 500-byte buffer. */
+static void
+inbound_cap_request_append (server *serv, char *buffer, gsize size,
+                            const char *name, time_t timestamp)
+{
+    if (strlen (buffer) + strlen (name) + 1 >= size)
+    {
+        EMIT_SIGNAL_TIMESTAMP (XP_TE_CAPREQ, serv->server_session,
+            buffer + 9, NULL, NULL, NULL, 0, timestamp);
+        tcp_sendf (serv, "%s\r\n", g_strchomp (buffer));
+        g_strlcpy (buffer, "CAP REQ :", size);
+    }
+    g_strlcat (buffer, name, size);
+    g_strlcat (buffer, " ", size);
+}
+
 static void inbound_request_new_caps (server *serv, const char *extensions_str,
 									 const message_tags_data *tags_data);
 
@@ -2094,6 +2112,32 @@ inbound_request_new_caps (server *serv, const char *extensions_str,
 				break;
 			}
 		}
+	}
+	/* Also request plugin-owned capabilities, without repeating core requests. */
+    for (i = 0; extensions[i]; i++)
+    {
+        gsize previous;
+        gboolean builtin = FALSE;
+        for (x = 0; x < G_N_ELEMENTS (supported_caps); x++)
+        {
+            if (!strcmp (extensions[i], supported_caps[x]))
+            {
+                builtin = TRUE;
+                break;
+            }
+        }
+        if (builtin || !plugin_requests_capability (serv, extensions[i]))
+            continue;
+        for (previous = 0; previous < i; previous++)
+        {
+            if (!strcmp (extensions[previous], extensions[i]))
+                break;
+        }
+        if (previous != i)
+            continue;
+        EMIT_SIGNAL_TIMESTAMP (XP_TE_CAPREQ, serv->server_session,
+            extensions[i], NULL, NULL, NULL, 0, tags_data->timestamp);
+        tcp_sendf (serv, "CAP REQ :%s\r\n", extensions[i]);
     }
 	g_strfreev (extensions);
 }
@@ -2161,6 +2205,8 @@ inbound_cap_ls (server *serv, char *nick, char *extensions_str,
 	gboolean want_cap = FALSE; /* format the CAP REQ string based on previous capabilities being requested or not */
 	gboolean sts_upgrade_triggered = FALSE;
 	char **extensions;
+	GString *requests = g_string_new (NULL);
+	GHashTable *seen = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, NULL);
 	int i;
 
 	if (g_str_has_prefix (extensions_str, "* "))
@@ -2226,16 +2272,23 @@ inbound_cap_ls (server *serv, char *nick, char *extensions_str,
 			}
 			want_cap = TRUE;
 			serv->waiting_on_sasl = TRUE;
-			g_strlcat (buffer, "sasl ", sizeof(buffer));
+			if (g_hash_table_add (seen, g_strdup ("sasl")))
+				g_string_append (requests, "sasl ");
 			continue;
 		}
 
-		for (x = 0; x < G_N_ELEMENTS(supported_caps); ++x)
+		for (x = 0; x < G_N_ELEMENTS (supported_caps); ++x)
         {
             if (!g_strcmp0 (extension, supported_caps[x]))
+                break;
+        }
+        if (x < G_N_ELEMENTS (supported_caps) ||
+            plugin_requests_capability (serv, extension))
         {
-				g_strlcat (buffer, extension, sizeof(buffer));
+            if (g_hash_table_add (seen, g_strdup (extension)))
-				g_strlcat (buffer, " ", sizeof(buffer));
+            {
+                g_string_append (requests, extension);
+                g_string_append_c (requests, ' ');
                 want_cap = TRUE;
             }
         }
@@ -2245,17 +2298,30 @@ inbound_cap_ls (server *serv, char *nick, char *extensions_str,
 
 	if (sts_upgrade_triggered)
     {
+        g_hash_table_destroy (seen);
+        g_string_free (requests, TRUE);
         return;
     }
 
 	if (want_cap)
     {
-		/* buffer + 9 = emit buffer without "CAP REQ :" */
+        char **tokens = g_strsplit (requests->str, " ", 0);
+        for (i = 0; tokens[i]; i++)
+        {
+            if (tokens[i][0])
+                inbound_cap_request_append (serv, buffer, sizeof (buffer),
+                    tokens[i], tags_data->timestamp);
+        }
+        g_strfreev (tokens);
+        if (buffer[9])
+        {
             EMIT_SIGNAL_TIMESTAMP (XP_TE_CAPREQ, serv->server_session,
-									  buffer + 9, NULL, NULL, NULL, 0,
+                buffer + 9, NULL, NULL, NULL, 0, tags_data->timestamp);
-									  tags_data->timestamp);
             tcp_sendf (serv, "%s\r\n", g_strchomp (buffer));
         }
+    }
+    g_hash_table_destroy (seen);
+    g_string_free (requests, TRUE);
 	if (!serv->waiting_on_sasl && !serv->waiting_on_cap)
 	{
 		/* if we use SASL, CAP END is dealt via raw numerics */

src/common/plugin.c

@@ -99,6 +99,7 @@ struct _zoitechat_hook
 	int tag;				/* for timers & FDs only */
 	int type;			/* HOOK_* */
 	int pri;	/* fd */	/* priority / fd for HOOK_FD only */
+	int cap_connection_id;
 };
 
 struct _zoitechat_list
@@ -143,7 +144,8 @@ enum
 	HOOK_PRINT_ATTRS  = 1 << 4, /* same as above, with attributes */
 	HOOK_TIMER        = 1 << 5, /* timeouts */
 	HOOK_FD           = 1 << 6, /* sockets & fds */
-	HOOK_DELETED      = 1 << 7  /* marked for deletion */
+	HOOK_DELETED      = 1 << 7, /* marked for deletion */
+	HOOK_CAPABILITY   = 1 << 9  /* script-owned CAP requests */
 };
 
 enum
@@ -351,6 +353,7 @@ plugin_add (session *sess, char *filename, void *handle, void *init_func,
 		pl->zoitechat_emit_print_attrs = zoitechat_emit_print_attrs;
 		pl->zoitechat_event_attrs_create = zoitechat_event_attrs_create;
 		pl->zoitechat_event_attrs_free = zoitechat_event_attrs_free;
+		pl->zoitechat_register_capability = zoitechat_register_capability;
 
 		/* run zoitechat_plugin_init, if it returns 0, close the plugin */
 		if (((zoitechat_init_func *)init_func) (pl, &pl->name, &pl->desc, &pl->version, arg) == 0)
@@ -1028,6 +1031,41 @@ zoitechat_unhook (zoitechat_plugin *ph, zoitechat_hook *hook)
 	return hook->userdata;
 }
 
+zoitechat_hook *
+zoitechat_register_capability (zoitechat_plugin *ph, const char *name, int flags,
+                              int connection_id, void *userdata)
+{
+    const unsigned char *p;
+    zoitechat_hook *hook;
+    if (flags != 0 || connection_id < -1 || !name || !name[0] || strlen (name) > 200 ||
+        strcmp (name, "sasl") == 0 || strcmp (name, "sts") == 0)
+        return NULL;
+    for (p = (const unsigned char *)name; *p; p++)
+    {
+        if (!g_ascii_islower (*p) && !g_ascii_isdigit (*p) &&
+            *p != '-' && *p != '.' && *p != '/' && *p != '_')
+            return NULL;
+    }
+    hook = plugin_add_hook (ph, HOOK_CAPABILITY, 0, name, NULL, NULL, 0, userdata);
+    hook->cap_connection_id = connection_id;
+    return hook;
+}
+
+gboolean
+plugin_requests_capability (server *serv, const char *name)
+{
+    GSList *entry;
+    for (entry = hook_list; entry; entry = entry->next)
+    {
+        zoitechat_hook *hook = entry->data;
+        if (hook && hook->type == HOOK_CAPABILITY &&
+            (hook->cap_connection_id == -1 || hook->cap_connection_id == serv->id) &&
+            strcmp (hook->name, name) == 0)
+            return TRUE;
+    }
+    return FALSE;
+}
+
 zoitechat_hook *
 zoitechat_hook_command (zoitechat_plugin *ph, const char *name, int pri,
 						  zoitechat_cmd_cb *callb, const char *help_text, void *userdata)
@@ -1187,6 +1225,9 @@ zoitechat_get_info (zoitechat_plugin *ph, const char *id)
 		return text_find_format_string (e);
 	}
 
+	if (strcmp (id, "api_plugin_caps") == 0)
+		return "1";
+
 	hash = str_hash (id);
 	/* do the session independant ones first */
 	switch (hash)

src/common/plugin.h

@@ -183,6 +183,7 @@ int plugin_emit_command (session *sess, char *name, char *word[], char *word_eol
 int plugin_emit_server (session *sess, char *name, char *word[], char *word_eol[],
 						time_t server_time);
 int plugin_emit_print (session *sess, char *word[], time_t server_time);
+gboolean plugin_requests_capability (server *serv, const char *name);
 int plugin_emit_dummy_print (session *sess, char *name);
 int plugin_emit_keypress (session *sess, unsigned int state, unsigned int keyval, gunichar key);
 GList* plugin_command_list(GList *tmp_list);

src/common/zoitechat-plugin.h

@@ -206,6 +206,10 @@ struct _zoitechat_plugin
 #endif
 
 
+/* api_plugin_caps=1: register before CAP LS; flags=0, connection_id=-1 for any. */
+zoitechat_hook *zoitechat_register_capability (zoitechat_plugin *ph,
+    const char *name, int flags, int connection_id, void *userdata);
+
 zoitechat_hook *
 zoitechat_hook_command (zoitechat_plugin *ph,
 		    const char *name,
@@ -425,6 +429,7 @@ zoitechat_pluginpref_list (zoitechat_plugin *ph,
 #define zoitechat_hook_server ((ZOITECHAT_PLUGIN_HANDLE)->zoitechat_hook_server)
 #define zoitechat_hook_server_attrs ((ZOITECHAT_PLUGIN_HANDLE)->zoitechat_hook_server_attrs)
 #define zoitechat_hook_print ((ZOITECHAT_PLUGIN_HANDLE)->zoitechat_hook_print)
+#define zoitechat_register_capability ((ZOITECHAT_PLUGIN_HANDLE)->zoitechat_register_capability)
 #define zoitechat_hook_print_attrs ((ZOITECHAT_PLUGIN_HANDLE)->zoitechat_hook_print_attrs)
 #define zoitechat_hook_timer ((ZOITECHAT_PLUGIN_HANDLE)->zoitechat_hook_timer)
 #define zoitechat_hook_fd ((ZOITECHAT_PLUGIN_HANDLE)->zoitechat_hook_fd)