feat(msg): add publisher-subscriber messaging

src/extra/lv_extra.c

@@ -42,6 +42,10 @@ void lv_extra_init(void)
     lv_grid_init();
 #endif
 
+#if LV_USE_MSG
+    lv_msg_init();
+#endif
+
 #if LV_USE_FS_FATFS != '\0'
     lv_fs_fatfs_init();
 #endif

src/extra/others/lv_others.h

@@ -18,6 +18,7 @@ extern "C" {
 #include "gridnav/lv_gridnav.h"
 #include "fragment/lv_fragment.h"
 #include "imgfont/lv_imgfont.h"
+#include "msg/lv_msg.h"
 
 /*********************
  *      DEFINES

src/extra/others/msg/lv_msg.c

@@ -0,0 +1,179 @@
+/**
+ * @file lv_msg.c
+ *
+ */
+
+/*********************
+ *      INCLUDES
+ *********************/
+#include "lv_msg.h"
+#if LV_USE_MSG
+
+#include "../../../misc/lv_assert.h"
+#include "../../../misc/lv_ll.h"
+
+/*********************
+ *      DEFINES
+ *********************/
+
+/**********************
+ *      TYPEDEFS
+ **********************/
+
+typedef struct {
+    uint32_t msg_id;
+    lv_msg_subscribe_cb_t callback;
+    void * user_data;
+    void * _priv_data;      /*Internal: used only store 'obj' in lv_obj_subscribe*/
+} sub_dsc_t;
+
+/**********************
+ *  STATIC PROTOTYPES
+ **********************/
+
+static void notify(lv_msg_t * m);
+static void obj_notify_cb(void * s, lv_msg_t * m);
+static void obj_delete_event_cb(lv_event_t * e);
+
+/**********************
+ *  STATIC VARIABLES
+ **********************/
+static lv_ll_t subs_ll;
+static lv_ll_t reqs_ll;
+
+/**********************
+ *  GLOBAL VARIABLES
+ **********************/
+lv_event_code_t LV_EVENT_MSG_RECEIVED;
+
+/**********************
+ *      MACROS
+ **********************/
+
+/**********************
+ *   GLOBAL FUNCTIONS
+ **********************/
+
+void lv_msg_init(void)
+{
+    LV_EVENT_MSG_RECEIVED = lv_event_register_id();
+    _lv_ll_init(&subs_ll, sizeof(sub_dsc_t));
+}
+
+void * lv_msg_subsribe(uint32_t msg_id, lv_msg_subscribe_cb_t cb, void * user_data)
+{
+    sub_dsc_t * s = _lv_ll_ins_tail(&subs_ll);
+    LV_ASSERT_MALLOC(s);
+    if(s == NULL) return NULL;
+
+    lv_memset_00(s, sizeof(*s));
+
+    s->msg_id = msg_id;
+    s->callback = cb;
+    s->user_data = user_data;
+    return s;
+}
+
+void * lv_msg_subsribe_obj(uint32_t msg_id, lv_obj_t * obj, void * user_data)
+{
+    sub_dsc_t * s = lv_msg_subsribe(msg_id, obj_notify_cb, user_data);
+    if(s == NULL) return NULL;
+    s->_priv_data = obj;
+
+    /*If not added yet, add a delete event cb which automatically unsubcribes the object*/
+    sub_dsc_t * s_first = lv_obj_get_event_user_data(obj, obj_delete_event_cb);
+    if(s_first == NULL) {
+        lv_obj_add_event_cb(obj, obj_delete_event_cb, LV_EVENT_DELETE, s);
+    }
+    return s;
+}
+
+void lv_msg_unsubscribe(void * s)
+{
+    LV_ASSERT_NULL(s);
+    _lv_ll_remove(&subs_ll, s);
+    lv_mem_free(s);
+}
+
+uint32_t lv_msg_id_range(uint32_t start, uint32_t end)
+{
+    if(start == end) return start;
+    else return start + (end << 16);
+}
+
+void lv_msg_send(uint32_t msg_id, const void * payload)
+{
+    lv_msg_t m;
+    lv_memset_00(&m, sizeof(m));
+    m.id = msg_id;
+    m.payload = payload;
+    notify(&m);
+}
+
+uint32_t lv_msg_get_id(lv_msg_t * m)
+{
+    return m->id;
+}
+
+const void * lv_msg_get_payload(lv_msg_t * m)
+{
+    return m->payload;
+}
+
+void * lv_msg_get_user_data(lv_msg_t * m)
+{
+    return m->user_data;
+}
+
+lv_msg_t * lv_event_get_msg(lv_event_t * e)
+{
+    if(e->code == LV_EVENT_MSG_RECEIVED) {
+        return lv_event_get_param(e);
+    }
+    else {
+        LV_LOG_WARN("Not interpreted with this event code");
+        return NULL;
+    }
+}
+
+
+
+/**********************
+ *   STATIC FUNCTIONS
+ **********************/
+
+static void notify(lv_msg_t * m)
+{
+    sub_dsc_t * s;
+    _LV_LL_READ(&subs_ll, s) {
+        if(s->msg_id == m->id && s->callback) {
+            m->user_data = s->user_data;
+            m->_priv_data = s->_priv_data;
+            s->callback(s, m);
+        }
+    }
+}
+
+static void obj_notify_cb(void * s, lv_msg_t * m)
+{
+    LV_UNUSED(s);
+    lv_event_send(m->_priv_data, LV_EVENT_MSG_RECEIVED, m);
+}
+
+static void obj_delete_event_cb(lv_event_t * e)
+{
+    lv_obj_t * obj = lv_event_get_target(e);
+
+    sub_dsc_t * s = _lv_ll_get_head(&subs_ll);
+    sub_dsc_t * s_next;
+    while(s) {
+        /*On unsubscribe the list changes s becomes invalid so get next item while it's surely valid*/
+        s_next = _lv_ll_get_next(&subs_ll, s);
+        if(s->_priv_data == obj) {
+            lv_msg_unsubscribe(s);
+        }
+        s = s_next;
+    }
+}
+
+#endif /*LV_USE_MSG*/

src/extra/others/msg/lv_msg.h

@@ -0,0 +1,124 @@
+/**
+ * @file lv_msg.h
+ *
+ */
+
+#ifndef LV_MSG_H
+#define LV_MSG_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*********************
+ *      INCLUDES
+ *********************/
+#include "../../../core/lv_obj.h"
+#if LV_USE_MSG
+
+/*********************
+ *      DEFINES
+ *********************/
+
+/**********************
+ *      TYPEDEFS
+ **********************/
+
+typedef struct {
+    uint32_t id;            /*Identifier of the message*/
+    void * user_data;       /*Set the the user_data set in `lv_msg_subscribe`*/
+    void * _priv_data;      /*Used internally*/
+    const void * payload;   /*Pointer to the data of the message*/
+} lv_msg_t;
+
+typedef void (*lv_msg_subscribe_cb_t)(void * s, lv_msg_t * msg);
+
+typedef void (*lv_msg_request_cb_t)(void * r, uint32_t msg_id);
+
+/**********************
+ * GLOBAL PROTOTYPES
+ **********************/
+
+/**
+ * Called internally to initialize the message module
+ */
+void lv_msg_init(void);
+
+/**
+ * Subscribe to an `msg_id`
+ * @param msg_id        the message ID to listen to
+ * @param cb            callback to call if a message with `msg_id` was sent
+ * @param user_data     arbitrary data which will be available in `cb` too
+ * @return              pointer to a "subscribe object". It can be used the unsubscribe.
+ */
+void * lv_msg_subsribe(uint32_t msg_id, lv_msg_subscribe_cb_t cb, void * user_data);
+
+/**
+ * Subscribe an `lv_obj` to a message.
+ * `LV_EVENT_MSG_RECEIVED` will be triggered if a message with matching ID was sent
+ * @param msg_id        the message ID to listen to
+ * @param obj           pointer to an `lv_obj`
+ * @param user_data     arbitrary data which will be available in `cb` too
+ * @return              pointer to a "subscribe object". It can be used the unsubscribe.
+ */
+void * lv_msg_subsribe_obj(uint32_t msg_id, lv_obj_t * obj, void * user_data);
+
+/**
+ * Cancel a previous subscription
+ * @param s             pointer to a "subscibe object".
+ *                      Return value of `lv_msg_subsribe` or `lv_msg_subsribe_obj`
+ */
+void lv_msg_unsubscribe(void * s);
+
+/**
+ * Send a message with a given ID and payload
+ * @param msg_id        ID of the message to send
+ * @param data          pointer to the data to send
+ */
+void lv_msg_send(uint32_t msg_id, const void * payload);
+
+/**
+ * Get the ID of a message object. Typically used in the subscriber callback.
+ * @param m             pointer to a message object
+ * @return              the ID of the message
+ */
+uint32_t lv_msg_get_id(lv_msg_t * m);
+
+/**
+ * Get the payload of a message object. Typically used in the subscriber callback.
+ * @param m             pointer to a message object
+ * @return              the payload of the message
+ */
+const void * lv_msg_get_payload(lv_msg_t * m);
+
+/**
+ * Get the user data of a message object. Typically used in the subscriber callback.
+ * @param m             pointer to a message object
+ * @return              the user data of the message
+ */
+void * lv_msg_get_user_data(lv_msg_t * m);
+
+/**
+ * Get the message object from an event object. Can be used in `LV_EVENT_MSG_RECEIVED` events.
+ * @param e     pointer to an event object
+ * @return      the message object or NULL if called with unrelated event code.
+ */
+lv_msg_t * lv_event_get_msg(lv_event_t * e);
+
+/**********************
+ * GLOBAL VARIABLES
+ **********************/
+
+extern lv_event_code_t LV_EVENT_MSG_RECEIVED;
+
+/**********************
+ *      MACROS
+ **********************/
+
+#endif /*LV_USE_MSG*/
+
+#ifdef __cplusplus
+} /*extern "C"*/
+#endif
+
+#endif /*LV_MSG_H*/

src/lv_conf_internal.h

@@ -2167,7 +2167,7 @@
     #endif
 #endif
 
-/*draw img in label or span obj */
+/*1: Support using images as font in label or span widgets */
 #ifndef LV_USE_IMGFONT
     #ifdef CONFIG_LV_USE_IMGFONT
         #define LV_USE_IMGFONT CONFIG_LV_USE_IMGFONT
@@ -2176,6 +2176,15 @@
     #endif
 #endif
 
+/*1: Enable a published subscriber based messaging system */
+#ifndef LV_USE_MSG
+    #ifdef CONFIG_LV_USE_MSG
+        #define LV_USE_MSG CONFIG_LV_USE_MSG
+    #else
+        #define LV_USE_MSG 0
+    #endif
+#endif
+
 /*==================
 * EXAMPLES
 *==================*/