add opt-in post-display print hooks

(cherry picked from commit d3f892e9a7)

docs/plugin-api-additions/compatibility.md

@@ -0,0 +1,24 @@
+# Optional plugin API additions (discussion #144)
+
+Existing hooks, callbacks, return values, context lookup, strings and menu behaviour
+remain unchanged. The C plugin function table gains four fixed append-only slots;
+unused slots are NULL. Older binaries use the unchanged prefix. A plugin must check
+the documented get_info() feature key before accessing a new slot on an older host.
+New Python modules are installed by Meson and the existing Windows copy/installer
+pipeline. Only modules present in the installation are exported; imports of
+zoitechat, hexchat and xchat retain their compatibility aliases.
+
+All APIs run on the client main thread unless explicitly documented otherwise.
+New reserved flags must be zero. These changes do not make old API calls thread-safe.
+
+Nested hook dispatch defers deleted-hook reclamation until its outermost return,
+so new observers can safely emit events and unhook themselves or other hooks.
+
+The optional asyncio module requires Python 3.7 or newer; older supported
+interpreters skip that module and retain the existing scripting API.
+
+Python reload drops the script/API modules while retaining the embedding module
+so callback and lib.ph pointer types keep the same CFFI identity.
+
+Server-hook insertion matches both raw and attrs hooks so documented priorities
+are honoured for mixed registrations, including new filtered attrs callbacks.

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.py

@@ -383,3 +383,24 @@ def find_context(server=None, channel=None):
         return None
 
     return Context(ctx)
+
+
+# Optional additive APIs live in separate modules so builds can select features.
+def __load_additive_features():
+    import importlib
+    import os
+
+    for suffix in ('fd', 'events', 'async', 'names', 'contexts',
+                   'post', 'filters', 'caps'):
+        if suffix == 'async' and sys.version_info < (3, 7):
+            continue
+        name = '_zoitechat_' + suffix
+        if not os.path.isfile(os.path.join(os.path.dirname(__file__), name + '.py')):
+            continue
+        module = importlib.import_module(name)
+        for symbol in module.__all__:
+            globals()[symbol] = getattr(module, symbol)
+            __all__.append(symbol)
+
+
+__load_additive_features()

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)

plugins/python/meson.build

@@ -27,7 +27,11 @@ python3_source = custom_target('python-bindings',
   command: [find_program('generate_plugin.py'), '@INPUT@', '@OUTPUT@']
 )
 
-install_data(['_zoitechat.py', 'zoitechat.py', 'xchat.py', 'hexchat.py'],
+# Include any selected additive API modules alongside the compatibility modules.
+python_api_files = run_command(python3, '-c',
+  'import glob,sys; print("\\n".join(sorted(glob.glob(sys.argv[1] + "/_zoitechat*.py"))))',
+  meson.current_source_dir(), check: true).stdout().strip().split('\n')
+install_data(python_api_files + ['zoitechat.py', 'xchat.py', 'hexchat.py'],
   install_dir: join_paths(get_option('libdir'), 'zoitechat/python')
 )
 

plugins/python/python.py

@@ -590,7 +590,12 @@ def _on_plugin_deinit():
     sys.stderr = sys.__stderr__
     pydoc.help = pydoc.Helper()
 
-    for mod in ('_zoitechat', 'zoitechat', 'xchat', '_zoitechat_embedded'):
+    # CFFI callbacks keep the embedding module's ffi/lib identity for the
+    # process lifetime; deleting it creates incompatible types on reload.
+    for mod in ('_zoitechat', 'zoitechat', 'hexchat', 'xchat',
+                '_zoitechat_fd', '_zoitechat_events', '_zoitechat_async',
+                '_zoitechat_names', '_zoitechat_contexts', '_zoitechat_post',
+                '_zoitechat_filters', '_zoitechat_caps'):
         try:
             del sys.modules[mod]
 

plugins/python/python3.vcxproj

@@ -52,6 +52,7 @@
     <None Include="xchat.py" />
     <None Include="hexchat.py" />
     <None Include="_zoitechat.py" />
+    <None Include="_zoitechat_*.py" />
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="$(IntDir)python.c" />

plugins/python/python38.vcxproj

@@ -52,6 +52,7 @@
     <None Include="xchat.py" />
     <None Include="hexchat.py" />
     <None Include="_zoitechat.py" />
+    <None Include="_zoitechat_*.py" />
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="$(IntDir)python.c" />

src/common/plugin.c

@@ -143,7 +143,8 @@ 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_PRINT_AFTER  = 1 << 8  /* post-display observers */
 };
 
 enum
@@ -176,6 +177,7 @@ enum
 
 GSList *plugin_list = NULL;	/* export for plugingui.c */
 static GSList *hook_list = NULL;
+static unsigned int plugin_dispatch_depth;
 
 extern const struct prefs vars[];	/* cfgfiles.c */
 
@@ -243,7 +245,7 @@ plugin_list_add (zoitechat_context *ctx, char *filename, const char *name,
 {
 	zoitechat_plugin *pl;
 
-	pl = g_new (zoitechat_plugin, 1);
+	pl = g_new0 (zoitechat_plugin, 1);
 	pl->handle = handle;
 	pl->filename = filename;
 	pl->context = ctx;
@@ -350,6 +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)
@@ -610,6 +613,7 @@ plugin_hook_run (session *sess, char *name, char *word[], char *word_eol[],
 	zoitechat_hook *hook;
 	int ret, eat = 0;
 
+	plugin_dispatch_depth++;
 	list = hook_list;
 	while (1)
 	{
@@ -619,6 +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;
+		}
+		if (type == HOOK_PRINT_AFTER)
+			hook->tag = 1;
 		hook->pl->context = sess;
 
 		/* run the plugin's callback function */
@@ -627,6 +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;
@@ -641,6 +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;
+		}
+
 		if ((ret & ZOITECHAT_EAT_ZOITECHAT) && (ret & ZOITECHAT_EAT_PLUGIN))
 		{
 			eat = 1;
@@ -655,6 +676,10 @@ plugin_hook_run (session *sess, char *name, char *word[], char *word_eol[],
 	}
 
 xit:
+	/* Nested callbacks can unhook entries still used by an outer dispatch.
+	 * Keep both hook objects and list links alive until the outermost return. */
+	if (--plugin_dispatch_depth != 0)
+		return eat;
 	/* really remove deleted hooks now */
 	list = hook_list;
 	while (list)
@@ -719,6 +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)
 {
@@ -806,7 +840,7 @@ plugin_insert_hook (zoitechat_hook *new_hook)
 			break;
 		case HOOK_SERVER:
 		case HOOK_SERVER_ATTRS:
-			new_hook_type = HOOK_SERVER | HOOK_PRINT_ATTRS;
+			new_hook_type = HOOK_SERVER | HOOK_SERVER_ATTRS;
 			break;
 		default:
 			new_hook_type = new_hook->type;
@@ -1022,6 +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)
@@ -1181,6 +1224,9 @@ zoitechat_get_info (zoitechat_plugin *ph, const char *id)
 		return text_find_format_string (e);
 	}
 
+	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

@@ -150,6 +150,15 @@ struct _zoitechat_plugin
 	void (*zoitechat_event_attrs_free) (zoitechat_plugin *ph,
 									  zoitechat_event_attrs *attrs);
 
+	/* Additive API slots: append only; old binary offsets are unchanged. */
+	zoitechat_hook *(*zoitechat_hook_print_after) (zoitechat_plugin *, const char *, int,
+		int, int (*)(char *[], zoitechat_event_attrs *, void *), void *);
+	zoitechat_hook *(*zoitechat_hook_server_filtered) (zoitechat_plugin *, const char *, int,
+		int, int, const char *, int (*)(char *[], char *[], zoitechat_event_attrs *, void *), void *);
+	zoitechat_hook *(*zoitechat_hook_print_filtered) (zoitechat_plugin *, const char *, int,
+		int, int, const char *, int (*)(char *[], zoitechat_event_attrs *, void *), void *);
+	zoitechat_hook *(*zoitechat_register_capability) (zoitechat_plugin *, const char *, int, int, void *);
+
 	/* PRIVATE FIELDS! */
 	void *handle;		/* from dlopen */
 	char *filename;	/* loaded from */
@@ -174,6 +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

@@ -2320,6 +2320,7 @@ text_emit_with_message (int index, session *sess, char *a, char *b, char *c, cha
 	if (!prefs.hex_away_omit_alerts || !sess->server->is_away)
 		sound_play_event (index);
 	display_event (sess, index, word, stripcolor_args, timestamp, message);
+	plugin_emit_print_after (sess, word, timestamp);
 }
 
 char *

src/common/zoitechat-plugin.h

@@ -193,10 +193,25 @@ struct _zoitechat_plugin
 	zoitechat_event_attrs *(*zoitechat_event_attrs_create) (zoitechat_plugin *ph);
 	void (*zoitechat_event_attrs_free) (zoitechat_plugin *ph,
 									  zoitechat_event_attrs *attrs);
+	/* Additive API slots: append only; old binary offsets are unchanged. */
+	zoitechat_hook *(*zoitechat_hook_print_after) (zoitechat_plugin *, const char *, int,
+		int, int (*)(char *[], zoitechat_event_attrs *, void *), void *);
+	zoitechat_hook *(*zoitechat_hook_server_filtered) (zoitechat_plugin *, const char *, int,
+		int, int, const char *, int (*)(char *[], char *[], zoitechat_event_attrs *, void *), void *);
+	zoitechat_hook *(*zoitechat_hook_print_filtered) (zoitechat_plugin *, const char *, int,
+		int, int, const char *, int (*)(char *[], zoitechat_event_attrs *, void *), void *);
+	zoitechat_hook *(*zoitechat_register_capability) (zoitechat_plugin *, const char *, int, int, void *);
+
 };
 #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,
@@ -416,6 +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)

win32/copy/copy.vcxproj

@@ -90,6 +90,7 @@
       <MSWindowsTheme Include="$(DepsRoot)\share\themes\MS-Windows\**\*" />
       <HicolorIcons Include="$(DepsRoot)\share\icons\hicolor\index.theme" />
       <HicolorIcons Include="$(DepsRoot)\share\icons\hicolor\**\*.*" />
+      <PythonAdditiveApis Include="..\..\plugins\python\_zoitechat_*.py" />
     </ItemGroup>
 
     <Copy SourceFiles="@(None)" DestinationFolder="$(ZoiteChatRel)" />
@@ -115,6 +116,7 @@
     <Copy SourceFiles="..\..\plugins\python\hexchat.py" DestinationFolder="$(ZoiteChatRel)\python" Condition="'$(Python3Enabled)'=='true' or '$(Python38Enabled)'=='true'" />
     <Copy SourceFiles="..\..\plugins\python\zoitechat.py" DestinationFolder="$(ZoiteChatRel)\python" Condition="'$(Python3Enabled)'=='true' or '$(Python38Enabled)'=='true'" />
     <Copy SourceFiles="..\..\plugins\python\_zoitechat.py" DestinationFolder="$(ZoiteChatRel)\python" Condition="'$(Python3Enabled)'=='true' or '$(Python38Enabled)'=='true'" />
+    <Copy SourceFiles="@(PythonAdditiveApis)" DestinationFolder="$(ZoiteChatRel)\python" Condition="('$(Python3Enabled)'=='true' or '$(Python38Enabled)'=='true') and '@(PythonAdditiveApis)' != ''" />
 
     <WriteLinesToFile File="$(ZoiteChatRel)portable-mode" Lines="2" Overwrite="true" />