[common/client] platform: abstract runtime services

client/include/interface/displayserver.h

@@ -27,6 +27,7 @@
 #include "common/types.h"
 #include "common/debug.h"
 #include "interface/clipboard.h"
+#include "interface/event_source.h"
 
 typedef enum LG_DSProperty
 {
@@ -103,18 +104,6 @@ LG_DSWaitFrameResult;
 
 #define LG_POINTER_COUNT (LG_POINTER_NOT_ALLOWED + 1)
 
-typedef void (*LG_DSEventCallback)(void * opaque);
-
-typedef struct LG_DSEventSource
-{
-  /* The callback must be nonblocking and tolerate spurious calls. The caller
-   * retains ownership of fd and opaque until display-server shutdown. */
-  int                fd;
-  LG_DSEventCallback callback;
-  void             * opaque;
-}
-LG_DSEventSource;
-
 typedef struct LG_DSInitParams
 {
   const char * title;

client/include/interface/event_source.h

@@ -0,0 +1,53 @@
+/**
+ * Looking Glass
+ * Copyright © 2017-2026 The Looking Glass Authors
+ * https://looking-glass.io
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef _H_I_EVENT_SOURCE_
+#define _H_I_EVENT_SOURCE_
+
+#include <stdbool.h>
+
+typedef bool (*LG_DSEventWake)(void * opaque);
+typedef bool (*LG_DSEventSubscribe)(void * opaque,
+    LG_DSEventWake callback, void * callbackOpaque);
+typedef void (*LG_DSEventUnsubscribe)(void * opaque);
+typedef void (*LG_DSEventDispatch)(void * opaque);
+
+typedef struct LG_DSEventSource
+{
+  void                  * opaque;
+  LG_DSEventSubscribe     subscribe;
+  LG_DSEventUnsubscribe   unsubscribe;
+  LG_DSEventDispatch      dispatch;
+}
+LG_DSEventSource;
+
+/* Notifications are coalesced until dispatch. The subscriber wake callback
+ * must be nonblocking, must not call back into the source, and returns true
+ * when the wake was delivered. Failed wakes may be retried by a later
+ * notification. Unsubscribe is synchronous with any wake already in
+ * progress. */
+
+static inline bool lgEventSourceValid(const LG_DSEventSource * source)
+{
+  return source && source->subscribe && source->unsubscribe &&
+    source->dispatch;
+}
+
+#endif