WM: message bus replacement for property notifiers

Use dynamically generated message publish/subscribe
so buttons and manipulators update properly.

This resolves common glitches where manipulators weren't updating
as well as the UI when add-ons exposed properties which
hard coded listeners weren't checking for.

Python can also publish/scribe changes via `bpy.msgbus`.

See D2917

4 files changed, 738 insertions, 0 deletions

diff --git a/source/blender/windowmanager/message_bus/intern/wm_message_bus.c b/source/blender/windowmanager/message_bus/intern/wm_message_bus.c
new file mode 100644
index 00000000000..0e7486fa293
--- /dev/null
+++ b/source/blender/windowmanager/message_bus/intern/wm_message_bus.c
@@ -0,0 +1,245 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/windowmanager/message_bus/intern/wm_message_bus.c
+ *  \ingroup wm
+ */
+
+#include <string.h>
+
+#include "BLI_utildefines.h"
+#include "BLI_listbase.h"
+
+#include "BLI_ghash.h"
+
+#include "WM_types.h"
+
+#include "MEM_guardedalloc.h"
+
+#include "message_bus/wm_message_bus.h"
+#include "message_bus/intern/wm_message_bus_intern.h"
+
+/* -------------------------------------------------------------------------- */
+/** \name Public API
+ * \{ */
+
+static wmMsgTypeInfo wm_msg_types[WM_MSG_TYPE_NUM] = {NULL};
+
+typedef void (*wmMsgTypeInitFn)(wmMsgTypeInfo *);
+
+static wmMsgTypeInitFn wm_msg_init_fn[WM_MSG_TYPE_NUM] = {
+	WM_msgtypeinfo_init_rna,
+	WM_msgtypeinfo_init_static,
+};
+
+void WM_msgbus_types_init(void)
+{
+	for (uint i = 0; i < WM_MSG_TYPE_NUM; i++) {
+		wm_msg_init_fn[i](&wm_msg_types[i]);
+	}
+}
+
+struct wmMsgBus *WM_msgbus_create(void)
+{
+	struct wmMsgBus *mbus = MEM_callocN(sizeof(*mbus), __func__);
+	const uint gset_reserve = 512;
+	for (uint i = 0; i < WM_MSG_TYPE_NUM; i++) {
+		wmMsgTypeInfo *info = &wm_msg_types[i];
+		mbus->messages_gset[i] = BLI_gset_new_ex(info->gset.hash_fn, info->gset.cmp_fn, __func__, gset_reserve);
+	}
+	return mbus;
+}
+
+void WM_msgbus_destroy(struct wmMsgBus *mbus)
+{
+	for (uint i = 0; i < WM_MSG_TYPE_NUM; i++) {
+		wmMsgTypeInfo *info = &wm_msg_types[i];
+		BLI_gset_free(mbus->messages_gset[i], info->gset.key_free_fn);
+	}
+	MEM_freeN(mbus);
+}
+
+void WM_msgbus_clear_by_owner(struct wmMsgBus *mbus, void *owner)
+{
+	wmMsgSubscribeKey *msg_key, *msg_key_next;
+	for (msg_key = mbus->messages.first; msg_key; msg_key = msg_key_next) {
+		msg_key_next = msg_key->next;
+
+		wmMsgSubscribeValueLink *msg_lnk_next;
+		for (wmMsgSubscribeValueLink *msg_lnk = msg_key->values.first; msg_lnk; msg_lnk = msg_lnk_next) {
+			msg_lnk_next = msg_lnk->next;
+			if (msg_lnk->params.owner == owner) {
+				if (msg_lnk->params.free_data) {
+					msg_lnk->params.free_data(msg_key, &msg_lnk->params);
+				}
+				BLI_remlink(&msg_key->values, msg_lnk);
+				MEM_freeN(msg_lnk);
+			}
+		}
+
+		if (BLI_listbase_is_empty(&msg_key->values)) {
+			wmMsgTypeInfo *info = &wm_msg_types[msg_key->msg->type];
+			BLI_remlink(&mbus->messages, msg_key);
+			bool ok = BLI_gset_remove(mbus->messages_gset[msg_key->msg->type], msg_key, info->gset.key_free_fn);
+			BLI_assert(ok);
+			UNUSED_VARS_NDEBUG(ok);
+		}
+	}
+}
+
+void WM_msg_dump(struct wmMsgBus *mbus, const char *info_str)
+{
+	printf(">>>> %s\n", info_str);
+	for (wmMsgSubscribeKey *key = mbus->messages.first; key; key = key->next) {
+		const wmMsgTypeInfo *info = &wm_msg_types[key->msg->type];
+		info->repr(stdout, key);
+	}
+	printf("<<<< %s\n", info_str);
+}
+
+void WM_msgbus_handle(struct wmMsgBus *mbus, struct bContext *C)
+{
+	if (mbus->messages_tag_count == 0) {
+		// printf("msgbus: skipping\n");
+		return;
+	}
+
+	if (false) {
+		WM_msg_dump(mbus, __func__);
+	}
+
+	// uint a = 0, b = 0;
+	for (wmMsgSubscribeKey *key = mbus->messages.first; key; key = key->next) {
+		for (wmMsgSubscribeValueLink *msg_lnk = key->values.first; msg_lnk; msg_lnk = msg_lnk->next) {
+			if (msg_lnk->params.tag) {
+				msg_lnk->params.notify(C, key, &msg_lnk->params);
+				msg_lnk->params.tag = false;
+				mbus->messages_tag_count -= 1;
+			}
+			// b++;
+		}
+		// a++;
+	}
+	BLI_assert(mbus->messages_tag_count == 0);
+	mbus->messages_tag_count = 0;
+	// printf("msgbus: keys=%u values=%u\n", a, b);
+}
+
+/**
+ * \param msg_key_test: Needs following #wmMsgSubscribeKey fields filled in:
+ * - msg.params
+ * - msg.head.type
+ * - msg.head.id
+ * .. other values should be zeroed.
+ *
+ * \return The key for this subscription.
+ * note that this is only needed in rare cases when the key needs further manipulation.
+ */
+wmMsgSubscribeKey *WM_msg_subscribe_with_key(
+        struct wmMsgBus *mbus,
+        const wmMsgSubscribeKey *msg_key_test,
+        const wmMsgSubscribeValue *msg_val_params)
+{
+	const uint type = msg_key_test->msg->type;
+	const wmMsgTypeInfo *info = &wm_msg_types[type];
+	wmMsgSubscribeKey *key;
+
+	BLI_assert(msg_key_test->msg->id != NULL);
+
+	void **r_key;
+	if (!BLI_gset_ensure_p_ex(mbus->messages_gset[type], msg_key_test, &r_key)) {
+		key = *r_key = MEM_mallocN(info->msg_key_size, __func__);
+		memcpy(key, msg_key_test, info->msg_key_size);
+		BLI_addtail(&mbus->messages, key);
+	}
+	else {
+		key = *r_key;
+		for (wmMsgSubscribeValueLink *msg_lnk = key->values.first; msg_lnk; msg_lnk = msg_lnk->next) {
+			if ((msg_lnk->params.notify == msg_val_params->notify) &&
+			    (msg_lnk->params.owner == msg_val_params->owner) &&
+			    (msg_lnk->params.user_data == msg_val_params->user_data))
+			{
+				return key;
+			}
+		}
+	}
+
+	wmMsgSubscribeValueLink *msg_lnk = MEM_mallocN(sizeof(wmMsgSubscribeValueLink), __func__);
+	msg_lnk->params = *msg_val_params;
+	BLI_addtail(&key->values, msg_lnk);
+	return key;
+}
+
+void WM_msg_publish_with_key(struct wmMsgBus *mbus, wmMsgSubscribeKey *msg_key)
+{
+	for (wmMsgSubscribeValueLink *msg_lnk = msg_key->values.first; msg_lnk; msg_lnk = msg_lnk->next) {
+		if (false) {  /* make an option? */
+			msg_lnk->params.notify(NULL, msg_key, &msg_lnk->params);
+		}
+		else {
+			if (msg_lnk->params.tag == false) {
+				msg_lnk->params.tag = true;
+				mbus->messages_tag_count += 1;
+			}
+		}
+	}
+}
+
+void WM_msg_id_update(
+        struct wmMsgBus *mbus,
+        struct ID *id_src, struct ID *id_dst)
+{
+	for (uint i = 0; i < WM_MSG_TYPE_NUM; i++) {
+		wmMsgTypeInfo *info = &wm_msg_types[i];
+		if (info->update_by_id != NULL) {
+			info->update_by_id(mbus, id_src, id_dst);
+		}
+	}
+}
+
+void WM_msg_id_remove(struct wmMsgBus *mbus, const struct ID *id)
+{
+	for (uint i = 0; i < WM_MSG_TYPE_NUM; i++) {
+		wmMsgTypeInfo *info = &wm_msg_types[i];
+		if (info->remove_by_id != NULL) {
+			info->remove_by_id(mbus, id);
+		}
+	}
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------------- */
+/** \name Internal API
+ *
+ * \note While we could have a separate type for ID's, use RNA since there is enough overlap.
+ * \{ */
+
+void wm_msg_subscribe_value_free(
+        wmMsgSubscribeKey *msg_key, wmMsgSubscribeValueLink *msg_lnk)
+{
+	if (msg_lnk->params.free_data) {
+		msg_lnk->params.free_data(msg_key, &msg_lnk->params);
+	}
+	BLI_remlink(&msg_key->values, msg_lnk);
+	MEM_freeN(msg_lnk);
+}
+
+/** \} */
diff --git a/source/blender/windowmanager/message_bus/intern/wm_message_bus_intern.h b/source/blender/windowmanager/message_bus/intern/wm_message_bus_intern.h
new file mode 100644
index 00000000000..8d7b9d4ced2
--- /dev/null
+++ b/source/blender/windowmanager/message_bus/intern/wm_message_bus_intern.h
@@ -0,0 +1,41 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/windowmanager/message_bus/intern/wm_message_bus_intern.h
+ *  \ingroup wm
+ */
+
+#ifndef __WM_MESSAGE_BUS_INTERN_H__
+#define __WM_MESSAGE_BUS_INTERN_H__
+
+/* wm_message_bus.h must be included first */
+
+struct wmMsgBus {
+	struct GSet *messages_gset[WM_MSG_TYPE_NUM];
+	/** Messages in order of being added. */
+	ListBase messages;
+	/** Avoid checking messages when no tags exist. */
+	uint     messages_tag_count;
+};
+
+void wm_msg_subscribe_value_free(
+        struct wmMsgSubscribeKey *msg_key, struct wmMsgSubscribeValueLink *msg_lnk);
+
+#endif /* __WM_MESSAGE_BUS_INTERN_H__ */
diff --git a/source/blender/windowmanager/message_bus/intern/wm_message_bus_rna.c b/source/blender/windowmanager/message_bus/intern/wm_message_bus_rna.c
new file mode 100644
index 00000000000..f9d8d968b84
--- /dev/null
+++ b/source/blender/windowmanager/message_bus/intern/wm_message_bus_rna.c
@@ -0,0 +1,316 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/windowmanager/intern/wm_message_bus_rna.c
+ *  \ingroup wm
+ */
+
+#include <stdio.h>
+#include "DNA_ID.h"
+
+#include "BLI_utildefines.h"
+#include "BLI_ghash.h"
+#include "BLI_listbase.h"
+
+#include "WM_types.h"
+#include "WM_message.h"
+#include "message_bus/intern/wm_message_bus_intern.h"
+
+#include "RNA_access.h"
+
+#include "MEM_guardedalloc.h"
+
+/* -------------------------------------------------------------------------- */
+
+BLI_INLINE uint void_hash_uint(const void *key)
+{
+	size_t y = (size_t)key >> (sizeof(void *));
+	return (unsigned int)y;
+}
+
+static uint wm_msg_rna_gset_hash(const void *key_p)
+{
+	const wmMsgSubscribeKey_RNA *key = key_p;
+	const wmMsgParams_RNA *params = &key->msg.params;
+//	printf("%s\n", RNA_struct_identifier(params->ptr.type));
+	uint k = void_hash_uint(params->ptr.type);
+	k     ^= void_hash_uint(params->ptr.data);
+	k     ^= void_hash_uint(params->ptr.id.data);
+	k     ^= void_hash_uint(params->prop);
+	return k;
+}
+static bool wm_msg_rna_gset_cmp(const void *key_a_p, const void *key_b_p)
+{
+	const wmMsgParams_RNA *params_a = &((const wmMsgSubscribeKey_RNA *)key_a_p)->msg.params;
+	const wmMsgParams_RNA *params_b = &((const wmMsgSubscribeKey_RNA *)key_b_p)->msg.params;
+	return !(
+		(params_a->ptr.type ==
+		 params_b->ptr.type) &&
+		(params_a->ptr.id.data ==
+		 params_b->ptr.id.data) &&
+		(params_a->ptr.data ==
+		 params_b->ptr.data) &&
+		(params_a->prop ==
+		 params_b->prop)
+	);
+}
+static void wm_msg_rna_gset_key_free(void *key_p)
+{
+	wmMsgSubscribeKey_RNA *key = key_p;
+	wmMsgSubscribeValueLink *msg_lnk_next;
+	for (wmMsgSubscribeValueLink *msg_lnk = key->head.values.first; msg_lnk; msg_lnk = msg_lnk_next) {
+		msg_lnk_next = msg_lnk->next;
+		wm_msg_subscribe_value_free(&key->head, msg_lnk);
+	}
+	if (key->msg.params.data_path != NULL) {
+		MEM_freeN(key->msg.params.data_path);
+	}
+	MEM_freeN(key);
+}
+
+static void wm_msg_rna_repr(FILE *stream, const wmMsgSubscribeKey *msg_key)
+{
+	const wmMsgSubscribeKey_RNA *m = (wmMsgSubscribeKey_RNA *)msg_key;
+	const char *none = "<none>";
+	fprintf(stream,
+	        "<wmMsg_RNA %p, "
+	        "id='%s', "
+	        "%s.%s values_len=%d\n",
+	        m, m->msg.head.id,
+	        m->msg.params.ptr.type ? RNA_struct_identifier(m->msg.params.ptr.type) : none,
+	        m->msg.params.prop ? RNA_property_identifier((PropertyRNA *)m->msg.params.prop) : none,
+	        BLI_listbase_count(&m->head.values));
+}
+
+static void wm_msg_rna_update_by_id(
+        struct wmMsgBus *mbus,
+        ID *id_src, ID *id_dst)
+{
+	GSet *gs = mbus->messages_gset[WM_MSG_TYPE_RNA];
+	GSetIterator gs_iter;
+	BLI_gsetIterator_init(&gs_iter, gs);
+	while (BLI_gsetIterator_done(&gs_iter) == false) {
+		wmMsgSubscribeKey_RNA *key = BLI_gsetIterator_getKey(&gs_iter);
+		BLI_gsetIterator_step(&gs_iter);
+		if (key->msg.params.ptr.id.data == id_src) {
+
+			/* GSet always needs updating since the key changes. */
+			BLI_gset_remove(gs, key, NULL);
+
+			/* Remove any non-persistent values, so a single persistent
+			 * value doesn't modify behavior for the rest. */
+			wmMsgSubscribeValueLink *msg_lnk_next;
+			for (wmMsgSubscribeValueLink *msg_lnk = key->head.values.first; msg_lnk; msg_lnk = msg_lnk_next) {
+				msg_lnk_next = msg_lnk->next;
+				if (msg_lnk->params.is_persistent == false) {
+					wm_msg_subscribe_value_free(&key->head, msg_lnk);
+				}
+			}
+
+			bool remove = true;
+
+			if (BLI_listbase_is_empty(&key->head.values)) {
+				/* Remove, no reason to keep. */
+			}
+			else if (key->msg.params.ptr.data == key->msg.params.ptr.id.data) {
+				/* Simple, just update the ID. */
+				key->msg.params.ptr.data = id_dst;
+				key->msg.params.ptr.id.data = id_dst;
+				remove = false;
+			}
+			else {
+				/* we need to resolve this from the  */
+				PointerRNA idptr;
+				RNA_id_pointer_create(id_dst, &idptr);
+				PointerRNA ptr;
+				PropertyRNA *prop;
+				if (!RNA_path_resolve(&idptr, key->msg.params.data_path, &ptr, &prop)) {
+					key->msg.params.ptr = ptr;
+					key->msg.params.prop = prop;
+					remove = false;
+				}
+			}
+
+			printf("AAA ~ %d\n", remove);
+			if (remove) {
+				/* Failed to persist, remove the key. */
+				BLI_remlink(&mbus->messages, key);
+				wm_msg_rna_gset_key_free(key);
+			}
+			else {
+				/* note that it's not impossible this key exists, however it is very unlikely
+				 * since a subscriber would need to register in the middle of an undo for eg. so assert for now. */
+				BLI_assert(!BLI_gset_haskey(gs, key));
+				BLI_gset_add(gs, key);
+			}
+		}
+	}
+}
+
+static void wm_msg_rna_remove_by_id(struct wmMsgBus *mbus, const ID *id)
+{
+	GSet *gs = mbus->messages_gset[WM_MSG_TYPE_RNA];
+	GSetIterator gs_iter;
+	BLI_gsetIterator_init(&gs_iter, gs);
+	while (BLI_gsetIterator_done(&gs_iter) == false) {
+		wmMsgSubscribeKey_RNA *key = BLI_gsetIterator_getKey(&gs_iter);
+		BLI_gsetIterator_step(&gs_iter);
+		if (key->msg.params.ptr.id.data == id) {
+			BLI_remlink(&mbus->messages, key);
+			BLI_gset_remove(gs, key, NULL);
+			wm_msg_rna_gset_key_free(key);
+		}
+	}
+}
+
+void WM_msgtypeinfo_init_rna(wmMsgTypeInfo *msgtype_info)
+{
+	msgtype_info->gset.hash_fn = wm_msg_rna_gset_hash;
+	msgtype_info->gset.cmp_fn = wm_msg_rna_gset_cmp;
+	msgtype_info->gset.key_free_fn = wm_msg_rna_gset_key_free;
+
+	msgtype_info->repr = wm_msg_rna_repr;
+	msgtype_info->update_by_id = wm_msg_rna_update_by_id;
+	msgtype_info->remove_by_id = wm_msg_rna_remove_by_id;
+
+	msgtype_info->msg_key_size = sizeof(wmMsgSubscribeKey_RNA);
+}
+
+/* -------------------------------------------------------------------------- */
+
+
+wmMsgSubscribeKey_RNA *WM_msg_lookup_rna(struct wmMsgBus *mbus, const wmMsgParams_RNA *msg_key_params)
+{
+	wmMsgSubscribeKey_RNA key_test;
+	key_test.msg.params = *msg_key_params;
+	return BLI_gset_lookup(mbus->messages_gset[WM_MSG_TYPE_RNA], &key_test);
+}
+
+void WM_msg_publish_rna_params(struct wmMsgBus *mbus, const wmMsgParams_RNA *msg_key_params)
+{
+	wmMsgSubscribeKey_RNA *key;
+
+	if ((key = WM_msg_lookup_rna(mbus, msg_key_params))) {
+		WM_msg_publish_with_key(mbus, &key->head);
+	}
+
+	/* Support anonymous subscribers, this may be some extra overhead
+	 * but we want to be able to be more ambiguous. */
+	if (msg_key_params->ptr.id.data || msg_key_params->ptr.data) {
+		wmMsgParams_RNA msg_key_params_anon = *msg_key_params;
+
+		/* We might want to enable this later? */
+		if (msg_key_params_anon.prop != NULL) {
+			/* All properties for this type. */
+			msg_key_params_anon.prop = NULL;
+			if ((key = WM_msg_lookup_rna(mbus, &msg_key_params_anon))) {
+				WM_msg_publish_with_key(mbus, &key->head);
+			}
+			msg_key_params_anon.prop = msg_key_params->prop;
+		}
+
+		msg_key_params_anon.ptr.id.data = NULL;
+		msg_key_params_anon.ptr.data = NULL;
+		if ((key = WM_msg_lookup_rna(mbus, &msg_key_params_anon))) {
+			WM_msg_publish_with_key(mbus, &key->head);
+		}
+
+		/* Support subscribers to a type. */
+		if (msg_key_params->prop) {
+			msg_key_params_anon.prop = NULL;
+			if ((key = WM_msg_lookup_rna(mbus, &msg_key_params_anon))) {
+				WM_msg_publish_with_key(mbus, &key->head);
+			}
+		}
+	}
+}
+
+void WM_msg_publish_rna(struct wmMsgBus *mbus, PointerRNA *ptr, PropertyRNA *prop)
+{
+	WM_msg_publish_rna_params(mbus, &(wmMsgParams_RNA){ .ptr = *ptr, .prop = prop, });
+}
+
+void WM_msg_subscribe_rna_params(
+        struct wmMsgBus *mbus,
+        const wmMsgParams_RNA *msg_key_params,
+        const wmMsgSubscribeValue *msg_val_params,
+        const char *id_repr)
+{
+	wmMsgSubscribeKey_RNA msg_key_test = {{NULL}};
+
+	/* use when added */
+	msg_key_test.msg.head.id = id_repr;
+	msg_key_test.msg.head.type = WM_MSG_TYPE_RNA;
+	/* for lookup */
+	msg_key_test.msg.params = *msg_key_params;
+
+	wmMsgSubscribeKey_RNA *msg_key = (wmMsgSubscribeKey_RNA *)WM_msg_subscribe_with_key(
+	        mbus, &msg_key_test.head, msg_val_params);
+
+	if (msg_val_params->is_persistent) {
+		if (msg_key->msg.params.data_path == NULL) {
+			if (msg_key->msg.params.ptr.data != msg_key->msg.params.ptr.id.data) {
+				/* We assume prop type can't change. */
+				msg_key->msg.params.data_path = RNA_path_from_ID_to_struct(&msg_key->msg.params.ptr);
+			}
+		}
+	}
+}
+
+void WM_msg_subscribe_rna(
+        struct wmMsgBus *mbus,
+        PointerRNA *ptr, const PropertyRNA *prop,
+        const wmMsgSubscribeValue *msg_val_params,
+        const char *id_repr)
+{
+	WM_msg_subscribe_rna_params(
+	        mbus,
+	        &(const wmMsgParams_RNA){
+	            .ptr = *ptr,
+	            .prop = prop,
+	        },
+	        msg_val_params, id_repr);
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------------- */
+/** \name ID variants of RNA API
+ *
+ * \note While we could have a separate type for ID's, use RNA since there is enough overlap.
+ * \{ */
+
+void WM_msg_subscribe_ID(
+        struct wmMsgBus *mbus, ID *id, const wmMsgSubscribeValue *msg_val_params,
+        const char *id_repr)
+{
+	wmMsgParams_RNA msg_key_params = {NULL};
+	RNA_id_pointer_create(id, &msg_key_params.ptr);
+	WM_msg_subscribe_rna_params(mbus, &msg_key_params, msg_val_params, id_repr);
+}
+
+void WM_msg_publish_ID(struct wmMsgBus *mbus, ID *id)
+{
+	wmMsgParams_RNA msg_key_params = {NULL};
+	RNA_id_pointer_create(id, &msg_key_params.ptr);
+	WM_msg_publish_rna_params(mbus, &msg_key_params);
+}
+
+/** \} */
diff --git a/source/blender/windowmanager/message_bus/intern/wm_message_bus_static.c b/source/blender/windowmanager/message_bus/intern/wm_message_bus_static.c
new file mode 100644
index 00000000000..59bebad7f7b
--- /dev/null
+++ b/source/blender/windowmanager/message_bus/intern/wm_message_bus_static.c
@@ -0,0 +1,136 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/windowmanager/intern/wm_message_bus_static.c
+ *  \ingroup wm
+ */
+
+#include <stdio.h>
+
+#include "BLI_utildefines.h"
+#include "BLI_ghash.h"
+#include "BLI_listbase.h"
+
+#include "WM_types.h"
+#include "WM_message.h"
+#include "message_bus/intern/wm_message_bus_intern.h"
+
+#include "MEM_guardedalloc.h"
+
+/* -------------------------------------------------------------------------- */
+
+static uint wm_msg_static_gset_hash(const void *key_p)
+{
+	const wmMsgSubscribeKey_Static *key = key_p;
+	const wmMsgParams_Static *params = &key->msg.params;
+	uint k = params->event;
+	return k;
+}
+static bool wm_msg_static_gset_cmp(const void *key_a_p, const void *key_b_p)
+{
+	const wmMsgParams_Static *params_a = &((const wmMsgSubscribeKey_Static *)key_a_p)->msg.params;
+	const wmMsgParams_Static *params_b = &((const wmMsgSubscribeKey_Static *)key_b_p)->msg.params;
+	return !(
+		(params_a->event ==
+		 params_b->event)
+	);
+}
+static void wm_msg_static_gset_key_free(void *key_p)
+{
+	wmMsgSubscribeKey *key = key_p;
+	wmMsgSubscribeValueLink *msg_lnk_next;
+	for (wmMsgSubscribeValueLink *msg_lnk = key->values.first; msg_lnk; msg_lnk = msg_lnk_next) {
+		msg_lnk_next = msg_lnk->next;
+		BLI_remlink(&key->values, msg_lnk);
+		MEM_freeN(msg_lnk);
+	}
+	MEM_freeN(key);
+}
+
+static void wm_msg_static_repr(FILE *stream, const wmMsgSubscribeKey *msg_key)
+{
+	const wmMsgSubscribeKey_Static *m = (wmMsgSubscribeKey_Static *)msg_key;
+	fprintf(stream,
+	        "<wmMsg_Static %p, "
+	        "id='%s', "
+	        "values_len=%d\n",
+	        m, m->msg.head.id,
+	        BLI_listbase_count(&m->head.values));
+}
+
+
+void WM_msgtypeinfo_init_static(wmMsgTypeInfo *msgtype_info)
+{
+	msgtype_info->gset.hash_fn = wm_msg_static_gset_hash;
+	msgtype_info->gset.cmp_fn = wm_msg_static_gset_cmp;
+	msgtype_info->gset.key_free_fn = wm_msg_static_gset_key_free;
+	msgtype_info->repr = wm_msg_static_repr;
+
+	msgtype_info->msg_key_size = sizeof(wmMsgSubscribeKey_Static);
+}
+
+/* -------------------------------------------------------------------------- */
+
+
+wmMsgSubscribeKey_Static *WM_msg_lookup_static(struct wmMsgBus *mbus, const wmMsgParams_Static *msg_key_params)
+{
+	wmMsgSubscribeKey_Static key_test;
+	key_test.msg.params = *msg_key_params;
+	return BLI_gset_lookup(mbus->messages_gset[WM_MSG_TYPE_STATIC], &key_test);
+}
+
+void WM_msg_publish_static_params(struct wmMsgBus *mbus, const wmMsgParams_Static *msg_key_params)
+{
+	wmMsgSubscribeKey_Static *key = WM_msg_lookup_static(mbus, msg_key_params);
+	if (key) {
+		WM_msg_publish_with_key(mbus, &key->head);
+	}
+}
+
+void WM_msg_publish_static(struct wmMsgBus *mbus, int event)
+{
+	WM_msg_publish_static_params(mbus, &(wmMsgParams_Static){ .event = event, });
+}
+
+void WM_msg_subscribe_static_params(
+        struct wmMsgBus *mbus,
+        const wmMsgParams_Static *msg_key_params,
+        const wmMsgSubscribeValue *msg_val_params,
+        const char *id_repr)
+{
+	wmMsgSubscribeKey_Static msg_key_test = {{NULL}};
+
+	/* use when added */
+	msg_key_test.msg.head.id = id_repr;
+	msg_key_test.msg.head.type = WM_MSG_TYPE_STATIC;
+	/* for lookup */
+	msg_key_test.msg.params = *msg_key_params;
+
+	WM_msg_subscribe_with_key(mbus, &msg_key_test.head, msg_val_params);
+}
+
+void WM_msg_subscribe_static(
+        struct wmMsgBus *mbus,
+        int event,
+        const wmMsgSubscribeValue *msg_val_params,
+        const char *id_repr)
+{
+	WM_msg_subscribe_static_params(mbus, &(const wmMsgParams_Static){ .event = event, }, msg_val_params, id_repr);
+}