input: add core bits of the new input layer

Register and unregister handlers.
Event dispatcher code.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

ui/input.c

@@ -0,0 +1,83 @@
+#include "sysemu/sysemu.h"
+#include "qapi-types.h"
+#include "ui/input.h"
+
+struct QemuInputHandlerState {
+    DeviceState       *dev;
+    QemuInputHandler  *handler;
+    int               id;
+    int               events;
+    QTAILQ_ENTRY(QemuInputHandlerState) node;
+};
+static QTAILQ_HEAD(, QemuInputHandlerState) handlers =
+    QTAILQ_HEAD_INITIALIZER(handlers);
+
+QemuInputHandlerState *qemu_input_handler_register(DeviceState *dev,
+                                                   QemuInputHandler *handler)
+{
+    QemuInputHandlerState *s = g_new0(QemuInputHandlerState, 1);
+    static int id = 1;
+
+    s->dev = dev;
+    s->handler = handler;
+    s->id = id++;
+    QTAILQ_INSERT_TAIL(&handlers, s, node);
+    return s;
+}
+
+void qemu_input_handler_activate(QemuInputHandlerState *s)
+{
+    QTAILQ_REMOVE(&handlers, s, node);
+    QTAILQ_INSERT_HEAD(&handlers, s, node);
+}
+
+void qemu_input_handler_unregister(QemuInputHandlerState *s)
+{
+    QTAILQ_REMOVE(&handlers, s, node);
+    g_free(s);
+}
+
+static QemuInputHandlerState*
+qemu_input_find_handler(uint32_t mask)
+{
+    QemuInputHandlerState *s;
+
+    QTAILQ_FOREACH(s, &handlers, node) {
+        if (mask & s->handler->mask) {
+            return s;
+        }
+    }
+    return NULL;
+}
+
+void qemu_input_event_send(QemuConsole *src, InputEvent *evt)
+{
+    QemuInputHandlerState *s;
+
+    if (!runstate_is_running() && !runstate_check(RUN_STATE_SUSPENDED)) {
+        return;
+    }
+
+    s = qemu_input_find_handler(1 << evt->kind);
+    s->handler->event(s->dev, src, evt);
+    s->events++;
+}
+
+void qemu_input_event_sync(void)
+{
+    QemuInputHandlerState *s;
+
+    if (!runstate_is_running() && !runstate_check(RUN_STATE_SUSPENDED)) {
+        return;
+    }
+
+    QTAILQ_FOREACH(s, &handlers, node) {
+        if (!s->events) {
+            continue;
+        }
+        if (s->handler->sync) {
+            s->handler->sync(s->dev);
+        }
+        s->events = 0;
+    }
+}