move zen vfs implementation to zenstore (#549)

* move zen vfs implementation to zenstore

1 files changed, 450 insertions, 0 deletions

diff --git a/src/zenstore/vfsimpl.cpp b/src/zenstore/vfsimpl.cpp
new file mode 100644
index 000000000..0a918d452
--- /dev/null
+++ b/src/zenstore/vfsimpl.cpp
@@ -0,0 +1,450 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#include <zenstore/vfsimpl.h>
+
+#include <zencore/fmtutils.h>
+#include <zencore/logging.h>
+#include <zenstore/cache/structuredcachestore.h>
+#include <zenstore/projectstore.h>
+#include <zenvfs/projfs.h>
+#include <zenvfs/vfs.h>
+
+#include <memory>
+#include <unordered_map>
+
+#if ZEN_WITH_VFS
+
+namespace zen {
+
+using namespace std::literals;
+
+//////////////////////////////////////////////////////////////////////////
+
+VfsOplogDataSource::VfsOplogDataSource(std::string_view ProjectId, std::string_view OplogId, Ref<ProjectStore> InProjectStore)
+: m_ProjectId(ProjectId)
+, m_OplogId(OplogId)
+, m_ProjectStore(std::move(InProjectStore))
+{
+}
+
+void
+VfsOplogDataSource::ReadNamedData(std::string_view Path, void* Buffer, uint64_t ByteOffset, uint64_t ByteCount)
+{
+	ZEN_UNUSED(Path, Buffer, ByteOffset, ByteCount);
+}
+
+void
+VfsOplogDataSource::ReadChunkData(const Oid& ChunkId, void* Buffer, uint64_t ByteOffset, uint64_t ByteCount)
+{
+	IoBuffer ChunkBuffer = m_ProjectStore->GetChunk(m_ProjectId, m_OplogId, ChunkId);
+	if (ChunkBuffer)
+	{
+		ZEN_ASSERT(ChunkBuffer.GetSize() >= ByteOffset);
+		ZEN_ASSERT(ChunkBuffer.GetSize() - ByteOffset >= ByteCount);
+		MutableMemoryView Target(Buffer, ByteCount);
+		Target.CopyFrom(ChunkBuffer.GetView().Mid(ByteOffset, ByteCount));
+	}
+}
+
+void
+VfsOplogDataSource::PopulateDirectory(std::string NodePath, VfsTreeNode& DirNode)
+{
+	// This should never be called
+	ZEN_UNUSED(NodePath, DirNode);
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+VfsCacheDataSource::VfsCacheDataSource(std::string_view NamespaceId, std::string_view BucketId, Ref<ZenCacheStore> InCacheStore)
+: m_NamespaceId(NamespaceId)
+, m_BucketId(BucketId)
+, m_CacheStore(std::move(InCacheStore))
+{
+}
+
+VfsCacheDataSource::~VfsCacheDataSource()
+{
+}
+
+void
+VfsCacheDataSource::ReadNamedData(std::string_view Name, void* Buffer, uint64_t ByteOffset, uint64_t ByteCount)
+{
+	if (auto DotIndex = Name.find_first_of('.'); DotIndex != std::string_view::npos)
+	{
+		Name = Name.substr(0, DotIndex);
+	}
+
+	IoHash HashKey = IoHash::FromHexString(Name);
+
+	CacheRequestContext CacheContext{};
+
+	ZenCacheValue Value;
+	if (m_CacheStore->Get(CacheContext, m_NamespaceId, m_BucketId, HashKey, /* out */ Value))
+	{
+		// TODO bounds check!
+		auto DataPtr = reinterpret_cast<const uint8_t*>(Value.Value.GetData()) + ByteOffset;
+
+		memcpy(Buffer, DataPtr, ByteCount);
+
+		return;
+	}
+}
+
+void
+VfsCacheDataSource::ReadChunkData(const Oid& ChunkId, void* Buffer, uint64_t ByteOffset, uint64_t ByteCount)
+{
+	ZEN_UNUSED(ChunkId, Buffer, ByteOffset, ByteCount);
+}
+
+void
+VfsCacheDataSource::PopulateDirectory(std::string NodePath, VfsTreeNode& DirNode)
+{
+	ZEN_UNUSED(NodePath, DirNode);
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+VfsServiceImpl::VfsServiceImpl()
+{
+}
+
+VfsServiceImpl::~VfsServiceImpl()
+{
+	Unmount();
+}
+
+void
+VfsServiceImpl::Mount(std::string_view MountPoint)
+{
+	ZEN_INFO("VFS mount requested at '{}'", MountPoint);
+
+#	if ZEN_PLATFORM_WINDOWS
+	if (!IsProjFsAvailable())
+	{
+		throw std::runtime_error("Projected File System component not available");
+	}
+#	endif
+
+	if (!m_MountpointPath.empty())
+	{
+		throw std::runtime_error("VFS already mounted");
+	}
+
+	m_MountpointPath = MountPoint;
+
+	RefreshVfs();
+}
+
+void
+VfsServiceImpl::Unmount()
+{
+	if (m_MountpointPath.empty())
+	{
+		return;
+	}
+
+	ZEN_INFO("unmounting VFS from '{}'", m_MountpointPath);
+
+	m_MountpointPath.clear();
+
+	RefreshVfs();
+}
+
+void
+VfsServiceImpl::AddService(Ref<ProjectStore>&& Ps)
+{
+	m_ProjectStore = std::move(Ps);
+
+	RefreshVfs();
+}
+
+void
+VfsServiceImpl::AddService(Ref<ZenCacheStore>&& Z$)
+{
+	m_ZenCacheStore = std::move(Z$);
+
+	RefreshVfs();
+}
+
+void
+VfsServiceImpl::RefreshVfs()
+{
+	if (m_VfsHost && m_MountpointPath.empty())
+	{
+		m_VfsHost->RequestStop();
+		m_VfsThread.join();
+		m_VfsHost.reset();
+		m_VfsThreadRunning.Reset();
+		m_VfsDataSource = nullptr;
+
+		return;
+	}
+
+	if (!m_VfsHost && !m_MountpointPath.empty())
+	{
+		m_VfsThread = std::thread(&VfsServiceImpl::VfsThread, this);
+		m_VfsThreadRunning.Wait();
+
+		// At this stage, m_VfsHost should be initialized
+
+		ZEN_ASSERT(m_VfsHost);
+	}
+
+	if (m_ProjectStore && m_VfsHost)
+	{
+		if (!m_VfsDataSource)
+		{
+			m_VfsDataSource = new VfsServiceDataSource(this);
+		}
+
+		m_VfsHost->AddMount("projects"sv, m_VfsDataSource);
+	}
+
+	if (m_ZenCacheStore && m_VfsHost)
+	{
+		if (!m_VfsDataSource)
+		{
+			m_VfsDataSource = new VfsServiceDataSource(this);
+		}
+
+		m_VfsHost->AddMount("ddc_cache"sv, m_VfsDataSource);
+	}
+}
+
+void
+VfsServiceImpl::VfsThread()
+{
+	SetCurrentThreadName("VFS");
+
+	ZEN_INFO("VFS service thread now RUNNING");
+
+	try
+	{
+		m_VfsHost = std::make_unique<VfsHost>(m_MountpointPath);
+		m_VfsHost->Initialize();
+
+		m_VfsThreadRunning.Set();
+		m_VfsHost->Run();
+	}
+	catch (const std::exception& Ex)
+	{
+		ZEN_WARN("exception caught in VFS thread: {}", Ex.what());
+
+		m_VfsThreadException = std::current_exception();
+	}
+
+	if (m_VfsHost)
+	{
+		m_VfsHost->Cleanup();
+	}
+
+	ZEN_INFO("VFS service thread now EXITING");
+}
+
+//////////////////////////////////////////////////////////////////////////
+
+Ref<VfsOplogDataSource>
+VfsServiceDataSource::GetOplogDataSource(std::string_view ProjectId, std::string_view OplogId)
+{
+	ExtendableStringBuilder<256> Key;
+	Key << ProjectId << "." << OplogId;
+	std::string StdKey{Key};
+
+	RwLock::ExclusiveLockScope _(m_Lock);
+
+	if (auto It = m_OplogSourceMap.find(StdKey); It == m_OplogSourceMap.end())
+	{
+		Ref<VfsOplogDataSource> NewSource{new VfsOplogDataSource(ProjectId, OplogId, m_VfsImpl->m_ProjectStore)};
+		m_OplogSourceMap[StdKey] = NewSource;
+		return NewSource;
+	}
+	else
+	{
+		return It->second;
+	}
+}
+
+Ref<VfsCacheDataSource>
+VfsServiceDataSource::GetCacheDataSource(std::string_view NamespaceId, std::string_view BucketId)
+{
+	ExtendableStringBuilder<256> Key;
+	Key << NamespaceId << "." << BucketId;
+	std::string StdKey{Key};
+
+	RwLock::ExclusiveLockScope _(m_Lock);
+
+	if (auto It = m_CacheSourceMap.find(StdKey); It == m_CacheSourceMap.end())
+	{
+		Ref<VfsCacheDataSource> NewSource{new VfsCacheDataSource(NamespaceId, BucketId, m_VfsImpl->m_ZenCacheStore)};
+		m_CacheSourceMap[StdKey] = NewSource;
+		return NewSource;
+	}
+	else
+	{
+		return It->second;
+	}
+}
+
+void
+VfsServiceDataSource::ReadNamedData(std::string_view Path, void* Buffer, uint64_t ByteOffset, uint64_t ByteCount)
+{
+	ZEN_UNUSED(Path, Buffer, ByteOffset, ByteCount);
+}
+
+void
+VfsServiceDataSource::ReadChunkData(const Oid& ChunkId, void* Buffer, uint64_t ByteOffset, uint64_t ByteCount)
+{
+	ZEN_UNUSED(ChunkId, Buffer, ByteOffset, ByteCount);
+}
+
+void
+VfsServiceDataSource::PopulateDirectory(std::string NodePath, VfsTreeNode& DirNode)
+{
+	if (NodePath == "projects"sv)
+	{
+		// Project enumeration
+
+		m_VfsImpl->m_ProjectStore->DiscoverProjects();
+
+		m_VfsImpl->m_ProjectStore->IterateProjects(
+			[&](ProjectStore::Project& Project) { DirNode.AddVirtualNode(Project.Identifier, m_VfsImpl->m_VfsDataSource); });
+	}
+	else if (NodePath.starts_with("projects\\"sv))
+	{
+		std::string_view ProjectId{NodePath};
+		ProjectId = ProjectId.substr(9);  // Skip "projects\"
+
+		if (std::string_view::size_type SlashOffset = ProjectId.find_first_of('\\'); SlashOffset == std::string_view::npos)
+		{
+			Ref<ProjectStore::Project> Project = m_VfsImpl->m_ProjectStore->OpenProject(ProjectId);
+
+			if (!Project)
+			{
+				// No such project found?
+
+				return;
+			}
+
+			// Oplog enumeration
+
+			std::vector<std::string> Oplogs = Project->ScanForOplogs();
+
+			for (auto& Oplog : Oplogs)
+			{
+				DirNode.AddVirtualNode(Oplog, m_VfsImpl->m_VfsDataSource);
+			}
+		}
+		else
+		{
+			std::string_view OplogId = ProjectId.substr(SlashOffset + 1);
+			ProjectId				 = ProjectId.substr(0, SlashOffset);
+
+			Ref<ProjectStore::Project> Project = m_VfsImpl->m_ProjectStore->OpenProject(ProjectId);
+
+			if (!Project)
+			{
+				// No such project found?
+
+				return;
+			}
+
+			// Oplog contents enumeration
+
+			if (Ref<ProjectStore::Oplog> Oplog = Project->OpenOplog(OplogId, /*AllowCompact*/ false, /*VerifyPathOnDisk*/ true))
+			{
+				Ref<VfsOplogDataSource> DataSource = GetOplogDataSource(ProjectId, OplogId);
+
+				// Get metadata for all chunks
+				std::vector<ProjectStore::Oplog::ChunkInfo> ChunkInfos = Oplog->GetAllChunksInfo(Project->RootDir);
+
+				std::unordered_map<zen::Oid, uint64_t> ChunkSizes;
+
+				for (const auto& Ci : ChunkInfos)
+				{
+					ChunkSizes[Ci.ChunkId] = Ci.ChunkSize;
+				}
+
+				auto EmitFilesForDataArray = [&](zen::CbArrayView DataArray) {
+					for (auto DataIter : DataArray)
+					{
+						if (zen::CbObjectView Data = DataIter.AsObjectView())
+						{
+							std::filesystem::path FileName(Data["filename"sv].AsU8String());
+							zen::Oid			  ChunkId = Data["id"sv].AsObjectId();
+
+							if (auto FindIt = ChunkSizes.find(ChunkId); FindIt != ChunkSizes.end())
+							{
+								DirNode.AddFileNode(FileName.string(), FindIt->second /* file size */, ChunkId, DataSource);
+							}
+							else
+							{
+								ZEN_WARN("no chunk metadata found for chunk {} (file: '{}')", ChunkId, FileName);
+							}
+						}
+					}
+				};
+
+				Oplog->IterateOplog(
+					[&](CbObjectView Op) {
+						EmitFilesForDataArray(Op["packagedata"sv].AsArrayView());
+						EmitFilesForDataArray(Op["bulkdata"sv].AsArrayView());
+					},
+					ProjectStore::Oplog::Paging{});
+
+				DirNode.AddFileNode("stats.json", 42, Oid::Zero);
+			}
+		}
+	}
+	else if (NodePath == "ddc_cache"sv)
+	{
+		// Namespace enumeration
+
+		std::vector<std::string> Namespaces = m_VfsImpl->m_ZenCacheStore->GetNamespaces();
+
+		for (auto& Namespace : Namespaces)
+		{
+			DirNode.AddVirtualNode(Namespace, m_VfsImpl->m_VfsDataSource);
+		}
+	}
+	else if (NodePath.starts_with("ddc_cache\\"sv))
+	{
+		std::string_view NamespaceId{NodePath};
+		NamespaceId = NamespaceId.substr(10);  // Skip "ddc_cache\"
+
+		auto& Cache = m_VfsImpl->m_ZenCacheStore;
+
+		if (std::string_view::size_type SlashOffset = NamespaceId.find_first_of('\\'); SlashOffset == std::string_view::npos)
+		{
+			// Bucket enumeration
+
+			if (auto NsInfo = Cache->GetNamespaceInfo(NamespaceId))
+			{
+				for (auto& BucketName : NsInfo->BucketNames)
+				{
+					DirNode.AddVirtualNode(BucketName, m_VfsImpl->m_VfsDataSource);
+				}
+			}
+		}
+		else
+		{
+			// Bucket contents enumeration
+
+			std::string_view BucketId = NamespaceId.substr(SlashOffset + 1);
+			NamespaceId				  = NamespaceId.substr(0, SlashOffset);
+
+			Ref<VfsCacheDataSource> DataSource = GetCacheDataSource(NamespaceId, BucketId);
+
+			auto Enumerator = [&](const IoHash& Key, const CacheValueDetails::ValueDetails& Details) {
+				ExtendableStringBuilder<64> KeyString;
+				Key.ToHexString(KeyString);
+				KeyString.Append(".udd");
+				DirNode.AddFileNode(KeyString, Details.Size, Oid::Zero, DataSource);
+			};
+
+			Cache->EnumerateBucketContents(NamespaceId, BucketId, Enumerator);
+		}
+	}
+}
+
+}  // namespace zen
+#endif