Added Dispatcher and fix sim (#54)

- Add dispatcher mechanism (a queue for function calls) and tests
- Added tests for MessageQueue
- Fix FreeRTOS config for simulator
- Explicit dependencies for touch-related libs, because minor version changes caused broken builds on CI.

tactility-core/src/dispatcher.c

@@ -0,0 +1,48 @@
+#include "dispatcher.h"
+
+#include "tactility_core.h"
+
+Dispatcher* tt_dispatcher_alloc(uint32_t message_count) {
+    Dispatcher* dispatcher = malloc(sizeof(Dispatcher));
+    *dispatcher = (Dispatcher) {
+        .queue = tt_message_queue_alloc(message_count, sizeof(DispatcherMessage)),
+        .mutex = tt_mutex_alloc(MutexTypeNormal),
+        .buffer = {
+            .callback = NULL,
+            .context = NULL
+        }
+    };
+    return dispatcher;
+}
+
+void tt_dispatcher_free(Dispatcher* dispatcher) {
+    tt_mutex_acquire(dispatcher->mutex, TtWaitForever);
+    tt_message_queue_reset(dispatcher->queue);
+    tt_message_queue_free(dispatcher->queue);
+    tt_mutex_release(dispatcher->mutex);
+    tt_mutex_free(dispatcher->mutex);
+    free(dispatcher);
+}
+
+void tt_dispatcher_dispatch(Dispatcher* dispatcher, Callback callback, void* context) {
+    DispatcherMessage message = {
+        .callback = callback,
+        .context = context
+    };
+    tt_mutex_acquire(dispatcher->mutex, TtWaitForever);
+    tt_message_queue_put(dispatcher->queue, &message, TtWaitForever);
+    tt_mutex_release(dispatcher->mutex);
+}
+
+bool tt_dispatcher_consume(Dispatcher* dispatcher, uint32_t timeout_ticks) {
+    tt_mutex_acquire(dispatcher->mutex, TtWaitForever);
+    if (tt_message_queue_get(dispatcher->queue, &(dispatcher->buffer), timeout_ticks) == TtStatusOk) {
+        DispatcherMessage* message = &(dispatcher->buffer);
+        message->callback(message->context);
+        tt_mutex_release(dispatcher->mutex);
+        return true;
+    } else {
+        tt_mutex_release(dispatcher->mutex);
+        return false;
+    }
+}

tactility-core/src/dispatcher.h

@@ -0,0 +1,36 @@
+/**
+* @file message_queue.h
+*
+* Dispatcher is a thread-safe message queue implementation for callbacks.
+*/
+#pragma once
+
+#include "message_queue.h"
+#include "mutex.h"
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef void (*Callback)(void* data);
+
+typedef struct {
+    Callback callback;
+    void* context;
+} DispatcherMessage;
+
+typedef struct {
+    MessageQueue* queue;
+    Mutex* mutex;
+    DispatcherMessage buffer; // Buffer for consuming a message
+} Dispatcher;
+
+Dispatcher* tt_dispatcher_alloc(uint32_t message_count);
+void tt_dispatcher_free(Dispatcher* dispatcher);
+void tt_dispatcher_dispatch(Dispatcher* dispatcher, Callback callback, void* context);
+bool tt_dispatcher_consume(Dispatcher* dispatcher, uint32_t timeout_ticks);
+
+#ifdef __cplusplus
+}
+#endif

tactility-core/src/message_queue.h

@@ -1,6 +1,9 @@
 /**
  * @file message_queue.h
- * MessageQueue
+ *
+ * MessageQueue is a wrapper for FreeRTOS xQueue functionality.
+ * There is no additional thread-safety on top of the xQueue functionality,
+ * so make sure you create a lock if needed.
  */
 #pragma once