handler: refactor connection checking

Add a new type of callback to Curl_handler which performs checks on
the connection. Alter RTSP so that it uses this callback to do its
own check on connection health.

1 files changed, 12 insertions, 0 deletions

diff --git a/lib/urldata.h b/lib/urldata.h
index e89d1d706..41f9408ba 100644
--- a/lib/urldata.h
+++ b/lib/urldata.h
@@ -829,6 +829,12 @@ struct Curl_handler {
   CURLcode (*readwrite)(struct Curl_easy *data, struct connectdata *conn,
                         ssize_t *nread, bool *readmore);
 
+  /* This function can perform various checks on the connection. See
+     CONNCHECK_* for more information about the checks that can be performed,
+     and CONNRESULT_* for the results that can be returned. */
+  unsigned int (*connection_check)(struct connectdata *conn,
+                                   unsigned int checks_to_perform);
+
   long defport;           /* Default port. */
   unsigned int protocol;  /* See CURLPROTO_* - this needs to be the single
                              specific protocol bit */
@@ -859,6 +865,12 @@ struct Curl_handler {
                                          HTTP proxy as HTTP proxies may know
                                          this protocol and act as a gateway */
 
+#define CONNCHECK_NONE 0                 /* No checks */
+#define CONNCHECK_ISDEAD (1<<0)          /* Check if the connection is dead. */
+
+#define CONNRESULT_NONE 0                /* No extra information. */
+#define CONNRESULT_DEAD (1<<0)           /* The connection is dead. */
+
 /* return the count of bytes sent, or -1 on error */
 typedef ssize_t (Curl_send)(struct connectdata *conn, /* connection data */
                             int sockindex,            /* socketindex */