SERVER-28624 Further reduce dependency on ReplicationExecutor type.

* Replace getDiagnosticString() with appendDiagnosticBSON() in TaskExecutors.
* Introduce appendDiagnostics to ReplicationCoordinator, to hide the implementation
  detail that ReplicationCoordinatorImpl has a TaskExecutor.

3 files changed, 12 insertions, 20 deletions

diff --git a/src/mongo/executor/task_executor.h b/src/mongo/executor/task_executor.h
index a17b6482451..04f911da5dc 100644
--- a/src/mongo/executor/task_executor.h
+++ b/src/mongo/executor/task_executor.h
@@ -134,9 +134,9 @@ public:
     virtual void join() = 0;
 
     /**
-     * Returns diagnostic information.
+     * Writes diagnostic information into "b".
      */
-    virtual std::string getDiagnosticString() const = 0;
+    virtual void appendDiagnosticBSON(BSONObjBuilder* b) const = 0;
 
     /**
      * Gets the current time.  Callbacks should use this method to read the system clock.
diff --git a/src/mongo/executor/thread_pool_task_executor.cpp b/src/mongo/executor/thread_pool_task_executor.cpp
index fcb27cd5c29..7d111ae6f95 100644
--- a/src/mongo/executor/thread_pool_task_executor.cpp
+++ b/src/mongo/executor/thread_pool_task_executor.cpp
@@ -188,30 +188,24 @@ void ThreadPoolTaskExecutor::join() {
     invariant(_unsignaledEvents.empty());
 }
 
-BSONObj ThreadPoolTaskExecutor::_getDiagnosticBSON() const {
+void ThreadPoolTaskExecutor::appendDiagnosticBSON(BSONObjBuilder* b) const {
     stdx::lock_guard<stdx::mutex> lk(_mutex);
-    BSONObjBuilder builder;
 
     // ThreadPool details
     // TODO: fill in
-    BSONObjBuilder poolCounters(builder.subobjStart("pool"));
+    BSONObjBuilder poolCounters(b->subobjStart("pool"));
     poolCounters.appendIntOrLL("inProgressCount", _poolInProgressQueue.size());
     poolCounters.done();
 
     // Queues
-    BSONObjBuilder queues(builder.subobjStart("queues"));
+    BSONObjBuilder queues(b->subobjStart("queues"));
     queues.appendIntOrLL("networkInProgress", _networkInProgressQueue.size());
     queues.appendIntOrLL("sleepers", _sleepersQueue.size());
     queues.done();
 
-    builder.appendIntOrLL("unsignaledEvents", _unsignaledEvents.size());
-    builder.append("shuttingDown", _inShutdown);
-    builder.append("networkInterface", _net->getDiagnosticString());
-    return builder.obj();
-}
-
-std::string ThreadPoolTaskExecutor::getDiagnosticString() const {
-    return _getDiagnosticBSON().toString();
+    b->appendIntOrLL("unsignaledEvents", _unsignaledEvents.size());
+    b->append("shuttingDown", _inShutdown);
+    b->append("networkInterface", _net->getDiagnosticString());
 }
 
 Date_t ThreadPoolTaskExecutor::now() {
@@ -376,6 +370,9 @@ void ThreadPoolTaskExecutor::cancel(const CallbackHandle& cbHandle) {
     invariant(cbHandle.isValid());
     auto cbState = checked_cast<CallbackState*>(getCallbackFromHandle(cbHandle));
     stdx::unique_lock<stdx::mutex> lk(_mutex);
+    if (_inShutdown) {
+        return;
+    }
     cbState->canceled.store(1);
     if (cbState->isNetworkOperation) {
         lk.unlock();
diff --git a/src/mongo/executor/thread_pool_task_executor.h b/src/mongo/executor/thread_pool_task_executor.h
index 98298624b80..9d6a6d940b9 100644
--- a/src/mongo/executor/thread_pool_task_executor.h
+++ b/src/mongo/executor/thread_pool_task_executor.h
@@ -68,7 +68,7 @@ public:
     void startup() override;
     void shutdown() override;
     void join() override;
-    std::string getDiagnosticString() const override;
+    void appendDiagnosticBSON(BSONObjBuilder* b) const;
     Date_t now() override;
     StatusWith<EventHandle> makeEvent() override;
     void signalEvent(const EventHandle& event) override;
@@ -147,11 +147,6 @@ private:
      */
     void runCallback(std::shared_ptr<CallbackState> cbState);
 
-    /**
-     * Returns bson for diagnostics
-     */
-    BSONObj _getDiagnosticBSON() const;
-
     // The network interface used for remote command execution and waiting.
     std::unique_ptr<NetworkInterface> _net;