Disallow memory allocation in [sg]etDcpConnHandler

By doing so we don't have to toggle to the NonAllocationGuard
in ep-engine as the method just wants to set/get a pointer
from the connection.

Change-Id: I4db69bc504497df18a5e9dcc0f7b7d6b690fdeae
Reviewed-on: http://review.couchbase.org/c/kv_engine/+/145803
Tested-by: Build Bot <build@couchbase.com>
Reviewed-by: Dave Rigby <daver@couchbase.com>

engines/ep/src/ep_engine.cc

@@ -1799,18 +1799,6 @@ void EventuallyPersistentEngine::releaseCookie(const void* cookie) {
     serverApi->cookie->release(cookie);
 }
 
-void EventuallyPersistentEngine::setDcpConnHandler(
-        const void* cookie, DcpConnHandlerIface* handler) {
-    NonBucketAllocationGuard guard;
-    serverApi->cookie->setDcpConnHandler(cookie, handler);
-}
-
-DcpConnHandlerIface* EventuallyPersistentEngine::getDcpConnHandler(
-        const void* cookie) {
-    NonBucketAllocationGuard guard;
-    return serverApi->cookie->getDcpConnHandler(cookie);
-}
-
 void EventuallyPersistentEngine::storeEngineSpecific(const void* cookie,
                                                      void* engine_data) {
     NonBucketAllocationGuard guard;
@@ -6246,16 +6234,15 @@ cb::engine_errc EventuallyPersistentEngine::dcpAddStream(const void* cookie,
 }
 
 ConnHandler* EventuallyPersistentEngine::tryGetConnHandler(const void* cookie) {
-    auto* iface = getDcpConnHandler(cookie);
+    auto* iface = serverApi->cookie->getDcpConnHandler(cookie);
     if (iface) {
         auto* handler = dynamic_cast<ConnHandler*>(iface);
         if (handler) {
             return handler;
         }
         throw std::logic_error(
                 "EventuallyPersistentEngine::tryGetConnHandler(): The "
-                "registered "
-                "connection handler is not a ConnHandler");
+                "registered connection handler is not a ConnHandler");
     }
 
     return nullptr;

engines/ep/src/ep_engine.h

@@ -535,9 +535,6 @@ class EventuallyPersistentEngine : public EngineIface, public DcpIface {
     void reserveCookie(const void* cookie);
     void releaseCookie(const void* cookie);
 
-    void setDcpConnHandler(const void* cookie, DcpConnHandlerIface* handler);
-    DcpConnHandlerIface* getDcpConnHandler(const void* cookie);
-
     void storeEngineSpecific(const void* cookie, void* engine_data);
 
     void* getEngineSpecific(const void* cookie);

include/memcached/server_cookie_iface.h

@@ -43,6 +43,10 @@ struct ServerCookieIface {
      * Set the DCP connection handler to be used for the connection the
      * provided cookie belongs to.
      *
+     * NOTE: No logging or memory allocation is allowed in the impl
+     *       of this as ep-engine will not try to set the memory
+     *       allocation guard before calling it
+     *
      * @param cookie The cookie provided by the core for the operation
      * @param handler The new handler (may be nullptr to clear the handler)
      */
@@ -53,6 +57,10 @@ struct ServerCookieIface {
      * Get the DCP connection handler for the connection the provided
      * cookie belongs to
      *
+     * NOTE: No logging or memory allocation is allowed in the impl
+     *       of this as ep-engine will not try to set the memory
+     *       allocation guard before calling it
+     *
      * @param cookie The cookie provided by the core for the operation
      * @return The handler stored for the connection (may be nullptr if
      *         none is specified)