Implement CUBEB_STREAM_PREF_EXCLUSIVE

Author: spycrab

include/cubeb/cubeb.h

@@ -217,11 +217,16 @@ typedef enum {
 
 /** Miscellaneous stream preferences. */
 typedef enum {
-  CUBEB_STREAM_PREF_NONE     = 0x00, /**< No stream preferences are requested. */
-  CUBEB_STREAM_PREF_LOOPBACK = 0x01 /**< Request a loopback stream. Should be
-                                         specified on the input params and an
-                                         output device to loopback from should
-                                         be passed in place of an input device. */
+  CUBEB_STREAM_PREF_NONE      = 0x00, /**< No stream preferences are requested. */
+  CUBEB_STREAM_PREF_LOOPBACK  = 0x01, /**< Request a loopback stream. Should be
+                                            specified on the input params and an
+                                            output device to loopback from should
+                                            be passed in place of an input device. */
+  CUBEB_STREAM_PREF_EXCLUSIVE = 0x02 /**<  (Windows / WASAPI only) Request that
+                                            this stream is run in exclusive mode
+                                            which results in lower latency but
+                                            doesn't allow other applications to
+                                            use the same device */
 } cubeb_stream_prefs;
 
 /** Stream format initialization parameters. */

src/cubeb.c

@@ -318,6 +318,11 @@ cubeb_stream_init(cubeb * context, cubeb_stream ** stream, char const * stream_n
     return r;
   }
 
+  if ((output_stream_params && output_stream_params->prefs) & CUBEB_STREAM_PREF_EXCLUSIVE || (input_stream_params && input_stream_params->prefs & CUBEB_STREAM_PREF_EXCLUSIVE)) {
+    if (strcmp(cubeb_get_backend_id(context), "wasapi") != 0)
+	  return CUBEB_ERROR_NOT_SUPPORTED;
+  }
+
   r = context->ops->stream_init(context, stream, stream_name,
                                 input_device,
                                 input_stream_params,