vapi: implement vapi_wait() for reads

Type: improvement

The function vapi_wait() is intended to allow a caller to block while
waiting until the API queue can be read/written. It was a stub that
returned VAPI_ENOTSUP. Add code which implements the wait on being able
to read an incoming message.

Had to touch a few other things in vapi.h to make checkstyle.sh happy
after changing the prototype of vapi_wait().

Signed-off-by: Matthew Smith <mgsmith@netgate.com>
Change-Id: Ida80c1a1d34fe297ab23268087be65ea53ad7040

src/vpp-api/vapi/vapi.c

@@ -989,9 +989,13 @@ again:
 }
 
 vapi_error_e
-vapi_wait (vapi_ctx_t ctx, vapi_wait_mode_e mode)
+vapi_wait (vapi_ctx_t ctx)
 {
-  return VAPI_ENOTSUP;
+  svm_queue_lock (ctx->vl_input_queue);
+  svm_queue_wait (ctx->vl_input_queue);
+  svm_queue_unlock (ctx->vl_input_queue);
+
+  return VAPI_OK;
 }
 
 static vapi_error_e

src/vpp-api/vapi/vapi.h

@@ -175,7 +175,7 @@ vapi_error_e vapi_send (vapi_ctx_t ctx, void *msg);
  *
  * @return VAPI_OK on success, other error code on error
  */
-  vapi_error_e vapi_send2 (vapi_ctx_t ctx, void *msg1, void *msg2);
+vapi_error_e vapi_send2 (vapi_ctx_t ctx, void *msg1, void *msg2);
 
 /**
  * @brief low-level api for reading messages from vpp
@@ -191,18 +191,17 @@ vapi_error_e vapi_send (vapi_ctx_t ctx, void *msg);
  *
  * @return VAPI_OK on success, other error code on error
  */
-  vapi_error_e vapi_recv (vapi_ctx_t ctx, void **msg, size_t * msg_size,
-			  svm_q_conditional_wait_t cond, u32 time);
+vapi_error_e vapi_recv (vapi_ctx_t ctx, void **msg, size_t *msg_size,
+			svm_q_conditional_wait_t cond, u32 time);
 
 /**
- * @brief wait for connection to become readable or writable
+ * @brief wait for connection to become readable
  *
  * @param ctx opaque vapi context
- * @param mode type of property to wait for - readability, writability or both
  *
  * @return VAPI_OK on success, other error code on error
  */
-  vapi_error_e vapi_wait (vapi_ctx_t ctx, vapi_wait_mode_e mode);
+vapi_error_e vapi_wait (vapi_ctx_t ctx);
 
 /**
  * @brief pick next message sent by vpp and call the appropriate callback

src/vpp-api/vapi/vapi_common.h

@@ -45,13 +45,6 @@ typedef enum
   VAPI_MODE_NONBLOCKING = 2, /**< operations never block */
 } vapi_mode_e;
 
-typedef enum
-{
-  VAPI_WAIT_FOR_READ,	     /**< wait until some message is readable */
-  VAPI_WAIT_FOR_WRITE,	     /**< wait until a message can be written */
-  VAPI_WAIT_FOR_READ_WRITE,  /**< wait until a read or write can be done */
-} vapi_wait_mode_e;
-
 typedef unsigned int vapi_msg_id_t;
 
 #define VAPI_INVALID_MSG_ID ((vapi_msg_id_t)(~0))