[FL-3833] Furi: event loop (#3675)

* Furi: epoll prototype

* Gui: simplify view_dispatcher custom event processing

* Furi: add missing critical sections to epoll

* Furi: add epoll unit tests, fully implement level processing for in and out events

* Furi: properly trigger epoll item event on adding mq, update tests.

* Unit tests: cleanup defines

* Furi: protect epoll from modification in callback

* Furi: rename epoll into event_loop, cleanup api naming

* Sync API Symbols

* Furi: add event loop contract and link api, port mq to new api, cleanup code

* Format Sources

* Furi: cleanup mq and event loop code

* Furi: remove unused staff from message queue

* ApiSymbols: remove event loop from public APIs.

* Fix furi unit tests

---------

Co-authored-by: Georgii Surkov <georgii.surkov@outlook.com>
Co-authored-by: Georgii Surkov <37121527+gsurkov@users.noreply.github.com>

furi/core/message_queue.c

@@ -1,9 +1,4 @@
-#include "kernel.h"
-#include "message_queue.h"
-#include "check.h"
-
-#include <FreeRTOS.h>
-#include <queue.h>
+#include "message_queue_i.h"
 
 // Internal FreeRTOS member names
 #define uxMessagesWaiting uxDummy4[0]
@@ -12,6 +7,10 @@
 
 struct FuriMessageQueue {
     StaticQueue_t container;
+
+    // Event Loop Link
+    FuriEventLoopLink event_loop_link;
+
     uint8_t buffer[];
 };
 
@@ -42,6 +41,10 @@ void furi_message_queue_free(FuriMessageQueue* instance) {
     furi_check(furi_kernel_is_irq_or_masked() == 0U);
     furi_check(instance);
 
+    // Event Loop must be disconnected
+    furi_check(!instance->event_loop_link.item_in);
+    furi_check(!instance->event_loop_link.item_out);
+
     vQueueDelete((QueueHandle_t)instance);
     free(instance);
 }
@@ -82,6 +85,11 @@ FuriStatus
         }
     }
 
+    if(stat == FuriStatusOk) {
+        furi_event_loop_link_notify(&instance->event_loop_link, FuriEventLoopEventIn);
+    }
+
+    /* Return execution status */
     return stat;
 }
 
@@ -120,6 +128,10 @@ FuriStatus furi_message_queue_get(FuriMessageQueue* instance, void* msg_ptr, uin
         }
     }
 
+    if(stat == FuriStatusOk) {
+        furi_event_loop_link_notify(&instance->event_loop_link, FuriEventLoopEventOut);
+    }
+
     return stat;
 }
 
@@ -182,5 +194,34 @@ FuriStatus furi_message_queue_reset(FuriMessageQueue* instance) {
         (void)xQueueReset(hQueue);
     }
 
+    if(stat == FuriStatusOk) {
+        furi_event_loop_link_notify(&instance->event_loop_link, FuriEventLoopEventOut);
+    }
+
+    /* Return execution status */
     return stat;
 }
+
+static FuriEventLoopLink* furi_message_queue_event_loop_get_link(void* object) {
+    FuriMessageQueue* instance = object;
+    furi_assert(instance);
+    return &instance->event_loop_link;
+}
+
+static uint32_t furi_message_queue_event_loop_get_level(void* object, FuriEventLoopEvent event) {
+    FuriMessageQueue* instance = object;
+    furi_assert(instance);
+
+    if(event == FuriEventLoopEventIn) {
+        return furi_message_queue_get_count(instance);
+    } else if(event == FuriEventLoopEventOut) {
+        return furi_message_queue_get_space(instance);
+    } else {
+        furi_crash();
+    }
+}
+
+const FuriEventLoopContract furi_message_queue_event_loop_contract = {
+    .get_link = furi_message_queue_event_loop_get_link,
+    .get_level = furi_message_queue_event_loop_get_level,
+};