add opt-in post-display print hooks

docs/plugin-api-additions/post.md

@@ -0,0 +1,21 @@
+# Post-display print observers
+
+Python: `hook_print_after(name, callback, userdata=None, priority=PRI_NORM)`.
+The callback is `(word, word_eol, userdata, attrs)`, matching hook_print_attrs().
+It runs after display_event() has handled the text, so prnt() follows the original
+text. Return values are ignored. Events eaten by a pre-hook or hidden by client
+preferences do not invoke these observers. This is post-display notification,
+not a notification that the entire incoming IRC command has finished updating state.
+
+C: `zoitechat_hook_print_after(ph, name, priority, flags, callback, userdata)`;
+flags must be zero. Check `get_info("api_hook_print_after")` for "1" before
+accessing the appended Windows function-table slot. Existing pre-hook timing is
+unchanged. Unhook/unload use existing lifecycle functions. Recursive emission
+skips an already-running observer to prevent it immediately invoking itself.
+
+```python
+def after(word, word_eol, userdata, attrs):
+    zoitechat.prnt('This follows the original channel message')
+
+zoitechat.hook_print_after('Channel Message', after)
+```

plugins/python/_zoitechat_post.py

@@ -0,0 +1,21 @@
+"""Opt-in post-display print observers."""
+import _zoitechat as api
+from _zoitechat_embedded import ffi, lib
+
+__all__ = ['hook_print_after']
+
+
+def hook_print_after(name, callback, userdata=None, priority=api.PRI_NORM):
+    """callback(word, word_eol, userdata, attrs); its return value is ignored."""
+    if not callable(callback):
+        raise TypeError('callback must be callable')
+    plugin = api.__get_current_plugin()
+    hook = plugin.add_hook(callback, userdata)
+    handle = lib.zoitechat_hook_print_after(lib.ph, name.encode(), priority, 0,
+                                           lib._on_print_attrs_hook, hook.handle)
+    if handle == ffi.NULL:
+        hook.is_unload = True
+        plugin.remove_hook(id(hook))
+        raise RuntimeError('unable to install post-display hook')
+    hook.zoitechat_hook = handle
+    return id(hook)

src/common/plugin.c

@@ -143,6 +143,7 @@ enum
 	HOOK_PRINT_ATTRS  = 1 << 4, /* same as above, with attributes */
 	HOOK_TIMER        = 1 << 5, /* timeouts */
 	HOOK_FD           = 1 << 6, /* sockets & fds */
+	HOOK_PRINT_AFTER  = 1 << 8, /* opt-in post-display observers */
 	HOOK_DELETED      = 1 << 7  /* marked for deletion */
 };
 
@@ -351,6 +352,7 @@ 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_hook_print_after = zoitechat_hook_print_after;
 
 		/* 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)
@@ -621,6 +623,13 @@ plugin_hook_run (session *sess, char *name, char *word[], char *word_eol[],
 
 		hook = list->data;
 		next = list->next;
+		if (type == HOOK_PRINT_AFTER && hook->tag)
+		{
+			list = next;
+			continue; /* no recursive invocation of this same observer */
+		}
+		if (type == HOOK_PRINT_AFTER)
+			hook->tag = 1;
 		hook->pl->context = sess;
 
 		/* run the plugin's callback function */
@@ -629,6 +638,7 @@ plugin_hook_run (session *sess, char *name, char *word[], char *word_eol[],
 		case HOOK_COMMAND:
 			ret = ((zoitechat_cmd_cb *)hook->callback) (word, word_eol, hook->userdata);
 			break;
+		case HOOK_PRINT_AFTER:
 		case HOOK_PRINT_ATTRS:
 			ret = ((zoitechat_print_attrs_cb *)hook->callback) (word, attrs, hook->userdata);
 			break;
@@ -643,6 +653,15 @@ plugin_hook_run (session *sess, char *name, char *word[], char *word_eol[],
 			break;
 		}
 
+		if (type == HOOK_PRINT_AFTER)
+		{
+			hook->tag = 0;
+			if (!is_session (sess))
+				goto xit;
+			list = next;
+			continue; /* display already happened; observers cannot eat it */
+		}
+
 		if ((ret & ZOITECHAT_EAT_ZOITECHAT) && (ret & ZOITECHAT_EAT_PLUGIN))
 		{
 			eat = 1;
@@ -725,6 +744,15 @@ plugin_emit_print (session *sess, char *word[], time_t server_time)
 							HOOK_PRINT | HOOK_PRINT_ATTRS);
 }
 
+void
+plugin_emit_print_after (session *sess, char *word[], time_t server_time)
+{
+	zoitechat_event_attrs attrs;
+	attrs.server_time_utc = server_time;
+	if (is_session (sess))
+		plugin_hook_run (sess, word[0], word, NULL, &attrs, HOOK_PRINT_AFTER);
+}
+
 int
 plugin_emit_dummy_print (session *sess, char *name)
 {
@@ -1028,6 +1056,15 @@ zoitechat_unhook (zoitechat_plugin *ph, zoitechat_hook *hook)
 	return hook->userdata;
 }
 
+zoitechat_hook *
+zoitechat_hook_print_after (zoitechat_plugin *ph, const char *name, int pri,
+                          int flags, zoitechat_print_attrs_cb *callback, void *userdata)
+{
+	if (flags != 0 || !name || !callback)
+		return NULL;
+	return plugin_add_hook (ph, HOOK_PRINT_AFTER, pri, name, NULL, callback, 0, userdata);
+}
+
 zoitechat_hook *
 zoitechat_hook_command (zoitechat_plugin *ph, const char *name, int pri,
 						  zoitechat_cmd_cb *callb, const char *help_text, void *userdata)
@@ -1197,6 +1234,9 @@ zoitechat_get_info (zoitechat_plugin *ph, const char *id)
 			? "ascii" : "rfc1459";
 	}
 
+	if (strcmp (id, "api_hook_print_after") == 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);
+void plugin_emit_print_after (session *sess, char *word[], time_t server_time);
 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/text.c

@@ -2306,6 +2306,7 @@ text_emit (int index, session *sess, char *a, char *b, char *c, char *d,
 	if (!prefs.hex_away_omit_alerts || !sess->server->is_away)
 		sound_play_event (index);
 	display_event (sess, index, word, stripcolor_args, timestamp);
+	plugin_emit_print_after (sess, word, timestamp);
 }
 
 char *

src/common/zoitechat-plugin.h

@@ -206,6 +206,12 @@ struct _zoitechat_plugin
 #endif
 
 
+/* api_hook_print_after=1: observer returns are ignored; flags must be zero. */
+zoitechat_hook *zoitechat_hook_print_after (zoitechat_plugin *ph,
+    const char *name, int pri, int flags,
+    int (*callback) (char *word[], zoitechat_event_attrs *attrs, void *userdata),
+    void *userdata);
+
 zoitechat_hook *
 zoitechat_hook_command (zoitechat_plugin *ph,
 		    const char *name,
@@ -425,6 +431,7 @@ 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_hook_print_after ((ZOITECHAT_PLUGIN_HANDLE)->zoitechat_hook_print_after)
 #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)