Move SSL management to a distinct private pointer. (#855)

We need to allow our users to use redisContext->privdata as context
for any RESP3 PUSH messages, which means we can't use it for managing
SSL connections.

Bulletpoints:

* Create a secondary redisContext member for internal use only called
  privctx and rename the redisContextFuncs->free_privdata accordingly.

* Adds a `free_privdata` function pointer so the user can tie allocated
  memory to the lifetime of a redisContext (like they can already do
  with redisAsyncContext)

* Enables SSL tests in .travis.yml

1 files changed, 17 insertions, 4 deletions

diff --git a/examples/example-push.c b/examples/example-push.c
index 23dbd17..2d4ab4d 100644
--- a/examples/example-push.c
+++ b/examples/example-push.c
@@ -97,6 +97,13 @@ void pushReplyHandler(void *privdata, void *r) {
     freeReplyObject(reply);
 }
 
+/* We aren't actually freeing anything here, but it is included to show that we can
+ * have hiredis call our data destructor when freeing the context */
+void privdata_dtor(void *privdata) {
+    unsigned int *icount = privdata;
+    printf("privdata_dtor():  In context privdata dtor (invalidations: %u)\n", *icount);
+}
+
 int main(int argc, char **argv) {
     unsigned int j, invalidations = 0;
     redisContext *c;
@@ -108,6 +115,16 @@ int main(int argc, char **argv) {
     redisOptions o = {0};
     REDIS_OPTIONS_SET_TCP(&o, hostname, port);
 
+    /* Set our context privdata to the address of our invalidation counter.  Each
+     * time our PUSH handler is called, hiredis will pass the privdata for context.
+     *
+     * This could also be done after we create the context like so:
+     *
+     *    c->privdata = &invalidations;
+     *    c->free_privdata = privdata_dtor;
+     */
+    REDIS_OPTIONS_SET_PRIVDATA(&o, &invalidations, privdata_dtor);
+
     /* Set our custom PUSH message handler */
     o.push_cb = pushReplyHandler;
 
@@ -118,10 +135,6 @@ int main(int argc, char **argv) {
     /* Enable RESP3 and turn on client tracking */
     enableClientTracking(c);
 
-    /* Set our context privdata to the address of our invalidation counter.  Each
-     * time our PUSH handler is called, hiredis will pass the privdata for context */
-    c->privdata = &invalidations;
-
     /* Set some keys and then read them back.  Once we do that, Redis will deliver
      * invalidation push messages whenever the key is modified */
     for (j = 0; j < KEY_COUNT; j++) {