Added a dummy sensor driver

src/sensor/SDL_sensor.c

@@ -33,12 +33,12 @@
 #endif
 
 static SDL_SensorDriver *SDL_sensor_drivers[] = {
-#if 0 //defined(__IPHONEOS__) || defined(__TVOS__)
-    &SDL_IOS_SensorDriver,
-#endif
 #ifdef SDL_SENSOR_ANDROID
     &SDL_ANDROID_SensorDriver,
 #endif
+#if defined(SDL_SENSOR_DUMMY) || defined(SDL_SENSOR_DISABLED)
+    &SDL_DUMMY_SensorDriver
+#endif
 };
 static SDL_Sensor *SDL_sensors = NULL;
 static SDL_bool SDL_updating_sensor = SDL_FALSE;
@@ -78,11 +78,6 @@ SDL_SensorInit(void)
     }
 #endif /* !SDL_EVENTS_DISABLED */
 
-    if (SDL_arraysize(SDL_sensor_drivers) == 0) {
-        /* What should we return here? We'll just return 0 with no sensors for now. */
-        status = 0;
-    }
-
     status = -1;
     for (i = 0; i < SDL_arraysize(SDL_sensor_drivers); ++i) {
         if (SDL_sensor_drivers[i]->Init() >= 0) {

src/sensor/SDL_syssensor.h

@@ -93,5 +93,6 @@ typedef struct _SDL_SensorDriver
 
 /* The available sensor drivers */
 extern SDL_SensorDriver SDL_ANDROID_SensorDriver;
+extern SDL_SensorDriver SDL_DUMMY_SensorDriver;
 
 /* vi: set ts=4 sw=4 expandtab: */

src/sensor/dummy/SDL_dummysensor.c

@@ -0,0 +1,110 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+#include "SDL_config.h"
+
+#if defined(SDL_SENSOR_DUMMY) || defined(SDL_SENSOR_DISABLED)
+
+#include "SDL_error.h"
+#include "SDL_sensor.h"
+#include "SDL_dummysensor.h"
+#include "../SDL_syssensor.h"
+
+static int
+SDL_DUMMY_SensorInit(void)
+{
+    return 0;
+}
+
+static int
+SDL_DUMMY_SensorGetCount(void)
+{
+    return 0;
+}
+
+static void
+SDL_DUMMY_SensorDetect(void)
+{
+}
+
+static const char *
+SDL_DUMMY_SensorGetDeviceName(int device_index)
+{
+    return NULL;
+}
+
+static SDL_SensorType
+SDL_DUMMY_SensorGetDeviceType(int device_index)
+{
+    return SDL_SENSOR_INVALID;
+}
+
+static int
+SDL_DUMMY_SensorGetDeviceNonPortableType(int device_index)
+{
+    return -1;
+}
+
+static SDL_SensorID
+SDL_DUMMY_SensorGetDeviceInstanceID(int device_index)
+{
+    return -1;
+}
+
+static int
+SDL_DUMMY_SensorOpen(SDL_Sensor *sensor, int device_index)
+{
+    return SDL_Unsupported();
+}
+    
+static void
+SDL_DUMMY_SensorUpdate(SDL_Sensor* sensor)
+{
+}
+
+static void
+SDL_DUMMY_SensorClose(SDL_Sensor * sensor)
+{
+}
+
+static void
+SDL_DUMMY_SensorQuit(void)
+{
+}
+
+SDL_SensorDriver SDL_DUMMY_SensorDriver =
+{
+    SDL_DUMMY_SensorInit,
+    SDL_DUMMY_SensorGetCount,
+    SDL_DUMMY_SensorDetect,
+    SDL_DUMMY_SensorGetDeviceName,
+    SDL_DUMMY_SensorGetDeviceType,
+    SDL_DUMMY_SensorGetDeviceNonPortableType,
+    SDL_DUMMY_SensorGetDeviceInstanceID,
+    SDL_DUMMY_SensorOpen,
+    SDL_DUMMY_SensorUpdate,
+    SDL_DUMMY_SensorClose,
+    SDL_DUMMY_SensorQuit,
+};
+
+#endif /* SDL_SENSOR_DUMMY || SDL_SENSOR_DISABLED */
+
+/* vi: set ts=4 sw=4 expandtab: */

src/sensor/dummy/SDL_dummysensor.h

@@ -0,0 +1,23 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_config.h"
+
+/* vi: set ts=4 sw=4 expandtab: */