vapi: Add option to dispatch with timeout

Type: improvement

Change-Id: I606efc90d9b1b8e2a2590a8b4e0021e2508642b2
Signed-off-by: Dau Do <daudo@yahoo.com>
diff --git a/src/vpp-api/vapi/vapi.c b/src/vpp-api/vapi/vapi.c
index 022f023..26c5708 100644
--- a/src/vpp-api/vapi/vapi.c
+++ b/src/vpp-api/vapi/vapi.c
@@ -1792,14 +1792,15 @@
 }
 
 vapi_error_e
-vapi_dispatch_one (vapi_ctx_t ctx)
+vapi_dispatch_one_timedwait (vapi_ctx_t ctx, u32 wait_time)
 {
   VAPI_DBG ("vapi_dispatch_one()");
   void *msg;
   uword size;
   svm_q_conditional_wait_t cond =
-    vapi_is_nonblocking (ctx) ? SVM_Q_NOWAIT : SVM_Q_WAIT;
-  vapi_error_e rv = vapi_recv (ctx, &msg, &size, cond, 0);
+    vapi_is_nonblocking (ctx) ? (wait_time ? SVM_Q_TIMEDWAIT : SVM_Q_NOWAIT) :
+				      SVM_Q_WAIT;
+  vapi_error_e rv = vapi_recv (ctx, &msg, &size, cond, wait_time);
   if (VAPI_OK != rv)
     {
       VAPI_DBG ("vapi_recv failed with rv=%d", rv);
@@ -1847,6 +1848,12 @@
 }
 
 vapi_error_e
+vapi_dispatch_one (vapi_ctx_t ctx)
+{
+  return vapi_dispatch_one_timedwait (ctx, 0);
+}
+
+vapi_error_e
 vapi_dispatch (vapi_ctx_t ctx)
 {
   vapi_error_e rv = VAPI_OK;
diff --git a/src/vpp-api/vapi/vapi.h b/src/vpp-api/vapi/vapi.h
index 970c508..8f092ee 100644
--- a/src/vpp-api/vapi/vapi.h
+++ b/src/vpp-api/vapi/vapi.h
@@ -225,6 +225,18 @@
 /**
  * @brief pick next message sent by vpp and call the appropriate callback
  *
+ * @note if using block mode, it will be blocked indefinitely until the next
+ * msg available. If using non-blocking mode, it will block for time_wait
+ * seconds until the next msg available if time_wait > 0, or does not block if
+ * time_wait == 0.
+ *
+ * @return VAPI_OK on success, other error code on error
+ */
+vapi_error_e vapi_dispatch_one_timedwait (vapi_ctx_t ctx, u32 wait_time);
+
+/**
+ * @brief pick next message sent by vpp and call the appropriate callback
+ *
  * @return VAPI_OK on success, other error code on error
  */
 vapi_error_e vapi_dispatch_one (vapi_ctx_t ctx);
@@ -235,11 +247,11 @@
  *
  * @note the dispatch loop is interrupted if any error is encountered or
  * returned from the callback, in which case this error is returned as the
- * result of vapi_dispatch. In this case it might be necessary to call dispatch
- * again to process the remaining messages. Returning VAPI_EUSER from
- * a callback allows the user to break the dispatch loop (and distinguish
- * this case in the calling code from other failures). VAPI never returns
- * VAPI_EUSER on its own.
+ * result of vapi_dispatch. In this case it might be necessary to call
+ * dispatch again to process the remaining messages. Returning VAPI_EUSER
+ * from a callback allows the user to break the dispatch loop (and
+ * distinguish this case in the calling code from other failures). VAPI never
+ * returns VAPI_EUSER on its own.
  *
  * @return VAPI_OK on success, other error code on error
  */