Fix event JSON reference count issues

It was noticed that vshl-capabilities was triggering the reference count
check in json-c and asserting:

../json-c-0.13.1/json_object.c:189: json_object_put: Assertion `jso->_ref_count > 0' failed.

Initially, this was only seen once during ad hoc testing, but
investigation into using the capabilities events started triggering it
reproducibly.  The root cause seems to be the capabilities binding
reusing the json-c objects it receives from voiceagent events to send
out itself.  That results in the objects getting json_object_put called
on them a second time by the app framework when they're resent.  To fix
this, call json_object_put on the reused objects to keep their reference
count correct and avoid triggering the assert.

Bug-AGL: SPEC-3053

Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Change-Id: I533bf492e740509cebd8d3487c9658e175fe73f9
(cherry picked from commit 6fc654713a65a0e72ee592fbd5e177702e33fbca)

1 files changed, 24 insertions, 0 deletions

diff --git a/src/plugins/VshlCapabilitiesApi.cpp b/src/plugins/VshlCapabilitiesApi.cpp
index 78c686f..f581b37 100644
--- a/src/plugins/VshlCapabilitiesApi.cpp
+++ b/src/plugins/VshlCapabilitiesApi.cpp
@@ -160,8 +160,14 @@ CTLP_CAPI(guiMetadataPublish, source, argsJ, eventJ) {
         return -1;        
     }
 
+    // Bump reference count on payload object since we're reusing it for downstream
+    json_object_get(payloadJ);
     if (!sCapabilityMessagingService->publish(guMetadataCapability, action, payloadJ)) {
         sLogger->log(Level::ERROR, TAG, "guimetadataPublish: Failed to publish message: " + action);
+        // The publish/forwarder code path returns false when there are no
+        // subscribers, without calling afb_event_push, so need to free
+        // payload to avoid leaking.
+        json_object_put(payloadJ);
         return -1;
     }
 
@@ -240,8 +246,14 @@ CTLP_CAPI(phonecontrolPublish, source, argsJ, eventJ) {
         return -1;        
     }
 
+    // Bump reference count on payload object since we're reusing it for downstream
+    json_object_get(payloadJ);
     if (!sCapabilityMessagingService->publish(phoneControlCapability, action, payloadJ)) {
         sLogger->log(Level::ERROR, TAG, "phoneControlPublish: Failed to publish message: " + action);
+        // The publish/forwarder code path returns false when there are no
+        // subscribers, without calling afb_event_push, so need to free
+        // payload to avoid leaking.
+        json_object_put(payloadJ);
         return -1;
     }
 
@@ -320,8 +332,14 @@ CTLP_CAPI(navigationPublish, source, argsJ, eventJ) {
         return -1;        
     }
 
+    // Bump reference count on payload object since we're reusing it for downstream
+    json_object_get(payloadJ);
     if (!sCapabilityMessagingService->publish(navigationCapability, action, payloadJ)) {
         sLogger->log(Level::ERROR, TAG, "navigationPublish: Failed to publish message: " + action);
+        // The publish/forwarder code path returns false when there are no
+        // subscribers, without calling afb_event_push, so need to free
+        // payload to avoid leaking.
+        json_object_put(payloadJ);
         return -1;
     }
 
@@ -400,8 +418,14 @@ CTLP_CAPI(playbackControllerPublish, source, argsJ, eventJ) {
         return -1;        
     }
 
+    // Bump reference count on payload object since we're reusing it for downstream
+    json_object_get(payloadJ);
     if (!sCapabilityMessagingService->publish(playbackcontrollerCapability, action, payloadJ)) {
         sLogger->log(Level::ERROR, TAG, "playbackControllerPublish: Failed to publish message: " + action);
+        // The publish/forwarder code path returns false when there are no
+        // subscribers, without calling afb_event_push, so need to free
+        // payload to avoid leaking.
+        json_object_put(payloadJ);
         return -1;
     }