Fix sensor framework timer issue and update sensor sample (#917)

Fix the sensor framework timer issue reported by #884 when setting
`ms_to_next_check`, and unify the type of time related args/vars to
uint32 to avoid potential type conversion issues, and fix the compile
warnings.

And update the sensor sample by creating two sensors to confirm that
the fix works correctly.

core/app-framework/sensor/native/runtime_sensor.c

@@ -9,7 +9,7 @@
 #include "bh_platform.h"
 
 static sys_sensor_t *g_sys_sensors = NULL;
-static int g_sensor_id_max = 0;
+static uint32 g_sensor_id_max = 0;
 
 static sensor_client_t *
 find_sensor_client(sys_sensor_t *sensor, unsigned int client_id,
@@ -85,8 +85,8 @@ wasm_sensor_callback(void *client, uint32 sensor_id, void *user_data)
 }
 
 bool
-wasm_sensor_config(wasm_exec_env_t exec_env, uint32 sensor, int interval,
-                   int bit_cfg, int delay)
+wasm_sensor_config(wasm_exec_env_t exec_env, uint32 sensor, uint32 interval,
+                   int bit_cfg, uint32 delay)
 {
     wasm_module_inst_t module_inst = get_module_inst(exec_env);
     attr_container_t *attr_cont;
@@ -115,9 +115,9 @@ wasm_sensor_config(wasm_exec_env_t exec_env, uint32 sensor, int interval,
 
     if (s->config != NULL) {
         attr_cont = attr_container_create("config sensor");
-        attr_container_set_int(&attr_cont, "interval", interval);
+        attr_container_set_int(&attr_cont, "interval", (int)interval);
         attr_container_set_int(&attr_cont, "bit_cfg", bit_cfg);
-        attr_container_set_int(&attr_cont, "delay", delay);
+        attr_container_set_int(&attr_cont, "delay", (int)delay);
         s->config(s, attr_cont);
         attr_container_destroy(attr_cont);
     }
@@ -138,7 +138,7 @@ wasm_sensor_open(wasm_exec_env_t exec_env, char *name, int instance)
         sensor_client_t *c;
         sys_sensor_t *s = find_sys_sensor(name, instance);
         if (s == NULL)
-            return -1;
+            return (uint32)-1;
 
         unsigned int mod_id =
             app_manager_get_module_id(Module_WASM_App, module_inst);
@@ -150,14 +150,14 @@ wasm_sensor_open(wasm_exec_env_t exec_env, char *name, int instance)
         if (c) {
             // the app already opened this sensor
             os_mutex_unlock(&s->lock);
-            return -1;
+            return (uint32)-1;
         }
 
         sensor_client_t *client =
             (sensor_client_t *)wasm_runtime_malloc(sizeof(sensor_client_t));
         if (client == NULL) {
             os_mutex_unlock(&s->lock);
-            return -1;
+            return (uint32)-1;
         }
 
         memset(client, 0, sizeof(sensor_client_t));
@@ -176,7 +176,7 @@ wasm_sensor_open(wasm_exec_env_t exec_env, char *name, int instance)
         return s->sensor_id;
     }
 
-    return -1;
+    return (uint32)-1;
 }
 
 bool
@@ -294,7 +294,7 @@ add_sys_sensor(char *name, char *description, int instance,
     }
 
     g_sensor_id_max++;
-    if (g_sensor_id_max == -1)
+    if (g_sensor_id_max == UINT32_MAX)
         g_sensor_id_max++;
     s->sensor_id = g_sensor_id_max;
 
@@ -366,10 +366,10 @@ find_sensor_client(sys_sensor_t *sensor, unsigned int client_id,
 }
 
 // return the milliseconds to next check
-int
+uint32
 check_sensor_timers()
 {
-    int ms_to_next_check = -1;
+    uint32 ms_to_next_check = UINT32_MAX;
     uint32 now = (uint32)bh_get_tick_ms();
 
     sys_sensor_t *s = g_sys_sensors;
@@ -395,12 +395,12 @@ check_sensor_timers()
 
             s->last_read = now;
 
-            if (ms_to_next_check == -1 || (ms_to_next_check < s->read_interval))
+            if (s->read_interval < ms_to_next_check)
                 ms_to_next_check = s->read_interval;
         }
         else {
-            int remaining = s->read_interval - elpased_ms;
-            if (ms_to_next_check == -1 || (ms_to_next_check < remaining))
+            uint32 remaining = s->read_interval - elpased_ms;
+            if (remaining < ms_to_next_check)
                 ms_to_next_check = remaining;
         }
 

core/app-framework/sensor/native/runtime_sensor.h

@@ -17,9 +17,9 @@ typedef struct _sys_sensor *sensor_obj_t;
 typedef struct _sensor_client {
     struct _sensor_client *next;
     unsigned int client_id; // the app id
-    int interval;
+    uint32 interval;
     int bit_cfg;
-    int delay;
+    uint32 delay;
     void (*client_callback)(void *client, uint32, attr_container_t *);
 } sensor_client_t;
 
@@ -54,7 +54,7 @@ void
 refresh_read_interval(sensor_obj_t sensor);
 void
 sensor_cleanup_callback(uint32 module_id);
-int
+uint32
 check_sensor_timers();
 void
 reschedule_sensor_read();

core/app-framework/sensor/native/sensor_mgr_ref.c

@@ -88,8 +88,8 @@ static void
 thread_sensor_check(void *arg)
 {
     while (sensor_check_thread_run) {
-        int ms_to_expiry = check_sensor_timers();
-        if (ms_to_expiry == -1)
+        uint32 ms_to_expiry = check_sensor_timers();
+        if (ms_to_expiry == UINT32_MAX)
             ms_to_expiry = 5000;
         os_mutex_lock(&mutex);
         os_cond_reltimedwait(&cond, &mutex, ms_to_expiry * 1000);

core/app-framework/sensor/native/sensor_native_api.h

@@ -14,8 +14,8 @@ extern "C" {
 #endif
 
 bool
-wasm_sensor_config(wasm_exec_env_t exec_env, uint32 sensor, int interval,
-                   int bit_cfg, int delay);
+wasm_sensor_config(wasm_exec_env_t exec_env, uint32 sensor, uint32 interval,
+                   int bit_cfg, uint32 delay);
 uint32
 wasm_sensor_open(wasm_exec_env_t exec_env, char *name, int instance);