SERVER-34751 Move StorageEngine ownership to ServiceContext from subclasses

8 files changed, 42 insertions, 44 deletions

diff --git a/src/mongo/client/embedded/service_context_embedded.cpp b/src/mongo/client/embedded/service_context_embedded.cpp
index 6a1c1ff72b7..7719cc80127 100644
--- a/src/mongo/client/embedded/service_context_embedded.cpp
+++ b/src/mongo/client/embedded/service_context_embedded.cpp
@@ -68,13 +68,6 @@ ServiceContextMongoEmbedded::ServiceContextMongoEmbedded() = default;
 
 ServiceContextMongoEmbedded::~ServiceContextMongoEmbedded() = default;
 
-StorageEngine* ServiceContextMongoEmbedded::getGlobalStorageEngine() {
-    // We don't check that globalStorageEngine is not-NULL here intentionally.  We can encounter
-    // an error before it's initialized and proceed to exitCleanly which is equipped to deal
-    // with a NULL storage engine.
-    return _storageEngine.get();
-}
-
 void ServiceContextMongoEmbedded::createLockFile() {
     try {
         _lockFile = stdx::make_unique<StorageEngineLockFile>(storageGlobalParams.dbpath);
@@ -106,7 +99,7 @@ void ServiceContextMongoEmbedded::createLockFile() {
 
 void ServiceContextMongoEmbedded::initializeGlobalStorageEngine() {
     // This should be set once.
-    invariant(!_storageEngine);
+    invariant(!getStorageEngine());
 
     // We should have a _lockFile or be in read-only mode. Confusingly, we can still have a lockFile
     // if we are in read-only mode. This can happen if the server is started in read-only mode on a
@@ -217,8 +210,9 @@ void ServiceContextMongoEmbedded::initializeGlobalStorageEngine() {
         }
     });
 
-    _storageEngine.reset(factory->create(storageGlobalParams, _lockFile.get()));
-    _storageEngine->finishInit();
+    setStorageEngine(
+        std::unique_ptr<StorageEngine>(factory->create(storageGlobalParams, _lockFile.get())));
+    getStorageEngine()->finishInit();
 
     if (_lockFile) {
         uassertStatusOK(_lockFile->writePid());
@@ -235,12 +229,12 @@ void ServiceContextMongoEmbedded::initializeGlobalStorageEngine() {
 
     guard.Dismiss();
 
-    _supportsDocLocking = _storageEngine->supportsDocLocking();
+    _supportsDocLocking = getStorageEngine()->supportsDocLocking();
 }
 
 void ServiceContextMongoEmbedded::shutdownGlobalStorageEngineCleanly() {
-    invariant(_storageEngine);
-    _storageEngine->cleanShutdown();
+    invariant(getStorageEngine());
+    getStorageEngine()->cleanShutdown();
     if (_lockFile) {
         _lockFile->clearPidAndUnlock();
     }
@@ -255,7 +249,7 @@ void ServiceContextMongoEmbedded::registerStorageEngine(const std::string& name,
     invariant(factory);
 
     // and all factories should be added before we pick a storage engine.
-    invariant(NULL == _storageEngine);
+    invariant(!getStorageEngine());
 
     _storageFactories[name].reset(factory);
 }
diff --git a/src/mongo/client/embedded/service_context_embedded.h b/src/mongo/client/embedded/service_context_embedded.h
index 5954060cd0e..873cb89b24e 100644
--- a/src/mongo/client/embedded/service_context_embedded.h
+++ b/src/mongo/client/embedded/service_context_embedded.h
@@ -45,8 +45,6 @@ public:
 
     ~ServiceContextMongoEmbedded();
 
-    StorageEngine* getGlobalStorageEngine() override;
-
     void createLockFile();
 
     void initializeGlobalStorageEngine() override;
@@ -65,8 +63,6 @@ private:
 
     std::unique_ptr<StorageEngineLockFile> _lockFile;
 
-    std::unique_ptr<StorageEngine> _storageEngine;
-
     // All possible storage engines are registered here through MONGO_INIT.
     FactoryMap _storageFactories;
 };
diff --git a/src/mongo/db/service_context.cpp b/src/mongo/db/service_context.cpp
index b3392b684bc..a61734e8cff 100644
--- a/src/mongo/db/service_context.cpp
+++ b/src/mongo/db/service_context.cpp
@@ -193,6 +193,12 @@ transport::ServiceExecutor* ServiceContext::getServiceExecutor() const {
     return _serviceExecutor.get();
 }
 
+void ServiceContext::setStorageEngine(std::unique_ptr<StorageEngine> engine) {
+    invariant(engine);
+    invariant(!_storageEngine);
+    _storageEngine = std::move(engine);
+}
+
 void ServiceContext::setOpObserver(std::unique_ptr<OpObserver> opObserver) {
     _opObserver = std::move(opObserver);
 }
diff --git a/src/mongo/db/service_context.h b/src/mongo/db/service_context.h
index 7ef549cac20..305a85c226f 100644
--- a/src/mongo/db/service_context.h
+++ b/src/mongo/db/service_context.h
@@ -267,9 +267,23 @@ public:
     virtual void shutdownGlobalStorageEngineCleanly() = 0;
 
     /**
+     * Sets the storage engine for this instance. May be called up to once per instance.
+     */
+    void setStorageEngine(std::unique_ptr<StorageEngine> engine);
+
+    /**
+     * Return the storage engine instance we're using.
+     */
+    StorageEngine* getStorageEngine() {
+        return _storageEngine.get();
+    }
+
+    /**
      * Return the storage engine instance we're using.
      */
-    virtual StorageEngine* getGlobalStorageEngine() = 0;
+    StorageEngine* getGlobalStorageEngine() {
+        return getStorageEngine();
+    }
 
     //
     // Global operation management.  This may not belong here and there may be too many methods
@@ -461,6 +475,11 @@ private:
     virtual std::unique_ptr<OperationContext> _newOpCtx(Client* client, unsigned opId) = 0;
 
     /**
+     * The storage engine, if any.
+     */
+    std::unique_ptr<StorageEngine> _storageEngine;
+
+    /**
      * The periodic runner.
      */
     std::unique_ptr<PeriodicRunner> _runner;
diff --git a/src/mongo/db/service_context_d.cpp b/src/mongo/db/service_context_d.cpp
index 3f8f1ef0961..4162f7150ca 100644
--- a/src/mongo/db/service_context_d.cpp
+++ b/src/mongo/db/service_context_d.cpp
@@ -70,13 +70,6 @@ ServiceContextMongoD::ServiceContextMongoD() = default;
 
 ServiceContextMongoD::~ServiceContextMongoD() = default;
 
-StorageEngine* ServiceContextMongoD::getGlobalStorageEngine() {
-    // We don't check that globalStorageEngine is not-NULL here intentionally.  We can encounter
-    // an error before it's initialized and proceed to exitCleanly which is equipped to deal
-    // with a NULL storage engine.
-    return _storageEngine;
-}
-
 void ServiceContextMongoD::createLockFile() {
     try {
         _lockFile.reset(new StorageEngineLockFile(storageGlobalParams.dbpath));
@@ -109,7 +102,7 @@ void ServiceContextMongoD::createLockFile() {
 
 void ServiceContextMongoD::initializeGlobalStorageEngine() {
     // This should be set once.
-    invariant(!_storageEngine);
+    invariant(!getStorageEngine());
 
     // We should have a _lockFile or be in read-only mode. Confusingly, we can still have a lockFile
     // if we are in read-only mode. This can happen if the server is started in read-only mode on a
@@ -220,8 +213,9 @@ void ServiceContextMongoD::initializeGlobalStorageEngine() {
         }
     });
 
-    _storageEngine = factory->create(storageGlobalParams, _lockFile.get());
-    _storageEngine->finishInit();
+    setStorageEngine(
+        std::unique_ptr<StorageEngine>(factory->create(storageGlobalParams, _lockFile.get())));
+    getStorageEngine()->finishInit();
 
     if (_lockFile) {
         uassertStatusOK(_lockFile->writePid());
@@ -238,12 +232,12 @@ void ServiceContextMongoD::initializeGlobalStorageEngine() {
 
     guard.Dismiss();
 
-    _supportsDocLocking = _storageEngine->supportsDocLocking();
+    _supportsDocLocking = getStorageEngine()->supportsDocLocking();
 }
 
 void ServiceContextMongoD::shutdownGlobalStorageEngineCleanly() {
-    invariant(_storageEngine);
-    _storageEngine->cleanShutdown();
+    invariant(getStorageEngine());
+    getStorageEngine()->cleanShutdown();
     if (_lockFile) {
         _lockFile->clearPidAndUnlock();
     }
@@ -258,7 +252,7 @@ void ServiceContextMongoD::registerStorageEngine(const std::string& name,
     invariant(factory);
 
     // and all factories should be added before we pick a storage engine.
-    invariant(NULL == _storageEngine);
+    invariant(!getStorageEngine());
 
     _storageFactories[name] = factory;
 }
diff --git a/src/mongo/db/service_context_d.h b/src/mongo/db/service_context_d.h
index 79b2126831a..9074cb07e51 100644
--- a/src/mongo/db/service_context_d.h
+++ b/src/mongo/db/service_context_d.h
@@ -45,8 +45,6 @@ public:
 
     ~ServiceContextMongoD();
 
-    StorageEngine* getGlobalStorageEngine() override;
-
     void createLockFile();
 
     void initializeGlobalStorageEngine() override;
@@ -65,9 +63,6 @@ private:
 
     std::unique_ptr<StorageEngineLockFile> _lockFile;
 
-    // logically owned here, but never deleted by anyone.
-    StorageEngine* _storageEngine = nullptr;
-
     // All possible storage engines are registered here through MONGO_INIT.
     FactoryMap _storageFactories;
 };
diff --git a/src/mongo/db/service_context_noop.cpp b/src/mongo/db/service_context_noop.cpp
index 59f40dfa710..59d0e696fb6 100644
--- a/src/mongo/db/service_context_noop.cpp
+++ b/src/mongo/db/service_context_noop.cpp
@@ -35,10 +35,6 @@
 
 namespace mongo {
 
-StorageEngine* ServiceContextNoop::getGlobalStorageEngine() {
-    return nullptr;
-}
-
 void ServiceContextNoop::initializeGlobalStorageEngine() {}
 
 void ServiceContextNoop::shutdownGlobalStorageEngineCleanly() {}
diff --git a/src/mongo/db/service_context_noop.h b/src/mongo/db/service_context_noop.h
index 251cd43310a..3bf4829cffe 100644
--- a/src/mongo/db/service_context_noop.h
+++ b/src/mongo/db/service_context_noop.h
@@ -34,8 +34,6 @@ namespace mongo {
 
 class ServiceContextNoop : public ServiceContext {
 public:
-    StorageEngine* getGlobalStorageEngine() override;
-
     void initializeGlobalStorageEngine() override;
 
     void shutdownGlobalStorageEngineCleanly() override;