MB-45756: Tidy EventuallyPersistentEngine memory management

Refactor EventuallyPersistentEngine to remove the usage of raw pointers
for members checkpointConfig & workload, replacing them with
std::unique_ptr<> to help simplify the dtor of
EventuallyPersistentEngine.

Change-Id: I1f6aa936699b7db6b80ed4d52c2f4b5d360acf57
Reviewed-on: http://review.couchbase.org/c/kv_engine/+/153256
Reviewed-by: Dave Rigby <daver@couchbase.com>
Tested-by: Build Bot <build@couchbase.com>

engines/ep/src/ep_engine.cc

@@ -2001,7 +2001,8 @@ cb::engine_errc EventuallyPersistentEngine::initialize(const char* config) {
             std::make_unique<EpEngineValueChangeListener>(*this));
 
     auto numShards = configuration.getMaxNumShards();
-    workload = new WorkLoadPolicy(configuration.getMaxNumWorkers(), numShards);
+    workload = std::make_unique<WorkLoadPolicy>(
+            configuration.getMaxNumWorkers(), numShards);
 
     const auto& confResMode = configuration.getConflictResolutionType();
     if (!setConflictResolutionMode(confResMode)) {
@@ -2031,7 +2032,7 @@ cb::engine_errc EventuallyPersistentEngine::initialize(const char* config) {
         dcpFlowControlManager_ = std::make_unique<DcpFlowControlManager>(*this);
     }
 
-    checkpointConfig = new CheckpointConfig(*this);
+    checkpointConfig = std::make_unique<CheckpointConfig>(*this);
     CheckpointConfig::addConfigChangeListener(*this);
 
     kvBucket = makeBucket(configuration);
@@ -6581,8 +6582,8 @@ EventuallyPersistentEngine::~EventuallyPersistentEngine() {
         waitForTasks(tasks);
     }
     EP_LOG_INFO("~EPEngine: Completed deinitialize.");
-    delete workload;
-    delete checkpointConfig;
+    workload.reset();
+    checkpointConfig.reset();
 
     // Engine going away, tell ArenaMalloc to unregister
     cb::ArenaMalloc::unregisterClient(arena);

engines/ep/src/ep_engine.h

@@ -1273,7 +1273,7 @@ class EventuallyPersistentEngine : public EngineIface, public DcpIface {
      */
     Configuration configuration;
     std::unique_ptr<KVBucket> kvBucket;
-    WorkLoadPolicy *workload;
+    std::unique_ptr<WorkLoadPolicy> workload;
     bucket_priority_t workloadPriority;
 
     // The conflict resolution mode for this bucket (as used by XDCR via
@@ -1287,7 +1287,7 @@ class EventuallyPersistentEngine : public EngineIface, public DcpIface {
 
     std::unique_ptr<DcpFlowControlManager> dcpFlowControlManager_;
     std::unique_ptr<DcpConnMap> dcpConnMap_;
-    CheckpointConfig *checkpointConfig;
+    std::unique_ptr<CheckpointConfig> checkpointConfig;
     std::string name;
     size_t maxItemSize;
     size_t maxItemPrivilegedBytes;

engines/ep/tests/mock/mock_synchronous_ep_engine.cc

@@ -60,13 +60,13 @@ SynchronousEPEngine::SynchronousEPEngine(const cb::ArenaMallocClient& client,
     // workload is needed by EPStore's constructor (to construct the
     // VBucketMap).
     auto shards = configuration.getMaxNumShards();
-    workload = new WorkLoadPolicy(/*workers*/ 1, shards);
+    workload = std::make_unique<WorkLoadPolicy>(/*workers*/ 1, shards);
 
     // dcpConnMap_ is needed by EPStore's constructor.
     dcpConnMap_ = std::make_unique<MockDcpConnMap>(*this);
 
     // checkpointConfig is needed by CheckpointManager (via EPStore).
-    checkpointConfig = new CheckpointConfig(*this);
+    checkpointConfig = std::make_unique<CheckpointConfig>(*this);
 
     // Simplified setup for switching FlowControl on/off
     if (configuration.getDcpFlowControlPolicy() == "none") {