fix concurrency issues in projectstore and enable GC (#181)

* Fix concurreny issues when deleting projects/oplogs
* remove rocksdb test code
* project store unit tests
* safer deletion of oplogs/projects
* reference count ProjectStore::Project to handle lifetime during GC
* Don't open all project oplogs unless we need them
* Don't scrub expired projects
* Don't gather references from expired projects
* added logging details for GC
* release lock as soon as folder is moved
* more tests for project store
* changelog

1 files changed, 50 insertions, 39 deletions

diff --git a/zenserver/projectstore.h b/zenserver/projectstore.h
index 91c0e1549..00fb613d9 100644
--- a/zenserver/projectstore.h
+++ b/zenserver/projectstore.h
@@ -117,7 +117,13 @@ public:
 		void			Scrub(ScrubContext& Ctx) const;
 		void			GatherReferences(GcContext& GcCtx);
 
-		std::size_t OplogCount() const { return m_LatestOpMap.size(); }
+		std::size_t OplogCount() const
+		{
+			RwLock::SharedLockScope _(m_OplogLock);
+			return m_LatestOpMap.size();
+		}
+
+		std::filesystem::path PrepareForDelete(bool MoveFolder);
 
 	private:
 		struct FileMapEntry
@@ -145,12 +151,16 @@ public:
 		RefPtr<OplogStorage> m_Storage;
 		std::string			 m_OplogId;
 
-		bool AddFileMapping(Oid FileId, IoHash Hash, std::string_view ServerPath, std::string_view ClientPath);
-		void AddChunkMapping(Oid ChunkId, IoHash Hash);
-		void AddMetaMapping(Oid ChunkId, IoHash Hash);
+		bool AddFileMapping(const RwLock::ExclusiveLockScope& OplogLock,
+							Oid								  FileId,
+							IoHash							  Hash,
+							std::string_view				  ServerPath,
+							std::string_view				  ClientPath);
+		void AddChunkMapping(const RwLock::ExclusiveLockScope& OplogLock, Oid ChunkId, IoHash Hash);
+		void AddMetaMapping(const RwLock::ExclusiveLockScope& OplogLock, Oid ChunkId, IoHash Hash);
 	};
 
-	struct Project
+	struct Project : public RefCounted
 	{
 		std::string			  Identifier;
 		std::filesystem::path RootDir;
@@ -158,16 +168,16 @@ public:
 		std::string			  ProjectRootDir;
 		std::string			  ProjectFilePath;
 
-		Oplog* NewOplog(std::string_view OplogId);
-		Oplog* OpenOplog(std::string_view OplogId);
-		void   DeleteOplog(std::string_view OplogId);
-		void   IterateOplogs(std::function<void(const Oplog&)>&& Fn) const;
-		void   IterateOplogs(std::function<void(Oplog&)>&& Fn);
-		void   DiscoverOplogs();
-		bool   IsExpired() const;
+		Oplog*					 NewOplog(std::string_view OplogId);
+		Oplog*					 OpenOplog(std::string_view OplogId);
+		void					 DeleteOplog(std::string_view OplogId);
+		void					 IterateOplogs(std::function<void(const Oplog&)>&& Fn) const;
+		void					 IterateOplogs(std::function<void(Oplog&)>&& Fn);
+		std::vector<std::string> ScanForOplogs() const;
+		bool					 IsExpired() const;
 
 		Project(ProjectStore* PrjStore, CidStore& Store, std::filesystem::path BasePath);
-		~Project();
+		virtual ~Project();
 
 		void					  Read();
 		void					  Write();
@@ -176,33 +186,34 @@ public:
 		void					  Scrub(ScrubContext& Ctx);
 		spdlog::logger&			  Log();
 		void					  GatherReferences(GcContext& GcCtx);
-		void					  Delete();
+		bool					  PrepareForDelete(std::filesystem::path& OutDeletePath);
 
 	private:
-		ProjectStore*				 m_ProjectStore;
-		CidStore&					 m_CidStore;
-		mutable RwLock				 m_ProjectLock;
-		std::map<std::string, Oplog> m_Oplogs;
-		std::filesystem::path		 m_OplogStoragePath;
+		ProjectStore*								  m_ProjectStore;
+		CidStore&									  m_CidStore;
+		mutable RwLock								  m_ProjectLock;
+		std::map<std::string, std::unique_ptr<Oplog>> m_Oplogs;
+		std::vector<std::unique_ptr<Oplog>>			  m_DeletedOplogs;
+		std::filesystem::path						  m_OplogStoragePath;
 
 		std::filesystem::path BasePathForOplog(std::string_view OplogId);
 	};
 
-	Oplog* OpenProjectOplog(std::string_view ProjectId, std::string_view OplogId);
-
-	Project* OpenProject(std::string_view ProjectId);
-	Project* NewProject(std::filesystem::path BasePath,
-						std::string_view	  ProjectId,
-						std::string_view	  RootDir,
-						std::string_view	  EngineRootDir,
-						std::string_view	  ProjectRootDir,
-						std::string_view	  ProjectFilePath);
-	void	 DeleteProject(std::string_view ProjectId, bool OnlyDeleteIfExpired);
-	bool	 Exists(std::string_view ProjectId);
-	void	 Flush();
-	void	 Scrub(ScrubContext& Ctx);
-	void	 DiscoverProjects();
-	void	 IterateProjects(std::function<void(Project& Prj)>&& Fn);
+	//	Oplog* OpenProjectOplog(std::string_view ProjectId, std::string_view OplogId);
+
+	Ref<Project> OpenProject(std::string_view ProjectId);
+	Ref<Project> NewProject(std::filesystem::path BasePath,
+							std::string_view	  ProjectId,
+							std::string_view	  RootDir,
+							std::string_view	  EngineRootDir,
+							std::string_view	  ProjectRootDir,
+							std::string_view	  ProjectFilePath);
+	bool		 DeleteProject(std::string_view ProjectId);
+	bool		 Exists(std::string_view ProjectId);
+	void		 Flush();
+	void		 Scrub(ScrubContext& Ctx);
+	void		 DiscoverProjects();
+	void		 IterateProjects(std::function<void(Project& Prj)>&& Fn);
 
 	spdlog::logger&				 Log() { return m_Log; }
 	const std::filesystem::path& BasePath() const { return m_ProjectBasePath; }
@@ -212,11 +223,11 @@ public:
 	virtual GcStorageSize StorageSize() const override;
 
 private:
-	spdlog::logger&				   m_Log;
-	CidStore&					   m_CidStore;
-	std::filesystem::path		   m_ProjectBasePath;
-	RwLock						   m_ProjectsLock;
-	std::map<std::string, Project> m_Projects;
+	spdlog::logger&						m_Log;
+	CidStore&							m_CidStore;
+	std::filesystem::path				m_ProjectBasePath;
+	RwLock								m_ProjectsLock;
+	std::map<std::string, Ref<Project>> m_Projects;
 
 	std::filesystem::path BasePathForProject(std::string_view ProjectId);
 };