[Spice-devel] [vdagent-win v2 1/2] vdagent: rework on event_dispatcher

[Victor Toso]

As _stop_event is not mandatory, we are initializing the events array
with something that might be NULL. The problem is with the following
patch as I'm introducing a new non mandatory event and logic starts to
get a bit hard to follow.

So this patch makes explicit if we are setting or receiving a
_stop_event or not and uses an auxiliary enum and array 'actions' to
work around this non mandatory events and the return value of
MsgWaitForMultipleObjectsEx()
---
 vdagent/vdagent.cpp | 39 ++++++++++++++++++++++++++++++---------
 1 file changed, 30 insertions(+), 9 deletions(-)

diff --git a/vdagent/vdagent.cpp b/vdagent/vdagent.cpp
index 959881d..d3cbd5f 100644
--- a/vdagent/vdagent.cpp
+++ b/vdagent/vdagent.cpp
@@ -478,12 +478,27 @@ void VDAgent::input_desktop_message_loop()
     CloseDesktop(hdesk);
 }
 
+#define G_N_ELEMENTS(arr)              (sizeof (arr) / sizeof ((arr)[0]))
+
 void VDAgent::event_dispatcher(DWORD timeout, DWORD wake_mask)
 {
-    HANDLE events[] = {_control_event, _stop_event};
-    DWORD event_count = _stop_event ? 2 : 1;
+    HANDLE events[2];
+    DWORD event_count = 1;
     DWORD wait_ret;
+    DWORD action;
     MSG msg;
+    enum {
+        CONTROL_ACTION,
+        STOP_ACTION,
+    } actions[G_N_ELEMENTS(events)];
+
+    events[0] = _control_event;
+    actions[0] = CONTROL_ACTION;
+    if (_stop_event) {
+        events[event_count] = _stop_event;
+        actions[event_count] = STOP_ACTION;
+        event_count++;
+    }
 
     wait_ret = MsgWaitForMultipleObjectsEx(event_count, events, timeout, wake_mask, MWMO_ALERTABLE);
     if (wait_ret == WAIT_OBJECT_0 + event_count) {
@@ -492,19 +507,25 @@ void VDAgent::event_dispatcher(DWORD timeout, DWORD wake_mask)
             DispatchMessage(&msg);
         }
         return;
+    } else if (wait_ret == WAIT_IO_COMPLETION || wait_ret == WAIT_TIMEOUT) {
+        return;
+    } else if (wait_ret < WAIT_OBJECT_0 || wait_ret > WAIT_OBJECT_0 + event_count) {
+        vd_printf("MsgWaitForMultipleObjectsEx failed: %lu %lu", wait_ret, GetLastError());
+        _running = false;
+        return;
     }
-    switch (wait_ret) {
-    case WAIT_OBJECT_0:
+
+    action = actions[wait_ret - WAIT_OBJECT_0];
+    switch (action) {
+    case CONTROL_ACTION:
         handle_control_event();
         break;
-    case WAIT_OBJECT_0 + 1:
+    case STOP_ACTION:
+        vd_printf("%s: received stop event", __func__);
         _running = false;
         break;
-    case WAIT_IO_COMPLETION:
-    case WAIT_TIMEOUT:
-        break;
     default:
-        vd_printf("MsgWaitForMultipleObjectsEx failed: %lu %lu", wait_ret, GetLastError());
+        vd_printf("%s: action not handled (%lu)", __func__, action);
         _running = false;
     }
 }
-- 
2.7.4