reserve: wrap device reservation monitor reference implementation

src/modules/reserve-monitor.h

@@ -0,0 +1,62 @@
+#ifndef fooreservemonitorhfoo
+#define fooreservemonitorhfoo
+
+/***
+  Copyright 2009 Lennart Poettering
+
+  Permission is hereby granted, free of charge, to any person
+  obtaining a copy of this software and associated documentation files
+  (the "Software"), to deal in the Software without restriction,
+  including without limitation the rights to use, copy, modify, merge,
+  publish, distribute, sublicense, and/or sell copies of the Software,
+  and to permit persons to whom the Software is furnished to do so,
+  subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be
+  included in all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+  BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+  ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+***/
+
+#include <dbus/dbus.h>
+#include <inttypes.h>
+
+typedef struct rm_monitor rm_monitor;
+
+/* Prototype for a function that is called whenever the reservation
+ * device of a device changes. Use rm_monitor_busy() to find out the
+ * new state.*/
+typedef void (*rm_change_cb_t)(rm_monitor *m);
+
+/* Creates a monitor for watching the lock status of a device. Returns
+ * 0 on success, a negative errno style return value on error.  The
+ * DBus error might be set as well if the error was caused D-Bus. */
+int rm_watch(
+	rm_monitor **m,              /* On success a pointer to the newly allocated rm_device object will be filled in here */
+	DBusConnection *connection,  /* Session bus (when D-Bus learns about user busses we should switchg to user busses) */
+	const char *device_name,     /* The device to monitor, e.g. "Audio0" */
+	rm_change_cb_t change_cb,    /* Will be called whenever the lock status changes. May be NULL */
+	DBusError *error);           /* If we fail due to a D-Bus related issue the error will be filled in here. May be NULL. */
+
+/* Free a rm_monitor object */
+void rm_release(rm_monitor *m);
+
+/* Checks whether the device is currently reserved, and returns 1
+ * then, 0 if not, negative errno style error code value on error. */
+int rm_busy(rm_monitor *m);
+
+/* Attach a userdata pointer to an rm_monitor */
+void rm_set_userdata(rm_monitor *m, void *userdata);
+
+/* Query the userdata pointer from an rm_monitor. Returns NULL if no
+ * userdata was set. */
+void* rm_get_userdata(rm_monitor *m);
+
+#endif