96 lines
3.6 KiB
C++
96 lines
3.6 KiB
C++
#pragma once
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#ifndef MESSMER_BLOBSTORE_IMPLEMENTATIONS_ONBLOCKS_DATATREE_H_
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#define MESSMER_BLOBSTORE_IMPLEMENTATIONS_ONBLOCKS_DATATREE_H_
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#include <memory>
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#include <cpp-utils/macros.h>
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#include <cpp-utils/pointer/optional_ownership_ptr.h>
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#include "../datanodestore/DataNodeView.h"
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//TODO Replace with C++14 once std::shared_mutex is supported
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#include <boost/thread/shared_mutex.hpp>
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#include <blockstore/utils/BlockId.h>
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#include "LeafHandle.h"
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#include "impl/CachedValue.h"
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namespace blobstore {
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namespace onblocks {
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namespace datanodestore {
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class DataNodeStore;
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class DataInnerNode;
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class DataLeafNode;
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class DataNode;
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}
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namespace datatreestore {
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//TODO It is strange that DataLeafNode is still part in the public interface of DataTree. This should be separated somehow.
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class DataTree final {
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public:
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DataTree(datanodestore::DataNodeStore *nodeStore, cpputils::unique_ref<datanodestore::DataNode> rootNode);
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~DataTree();
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const blockstore::BlockId &blockId() const;
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//Returning uint64_t, because calculations handling this probably need to be done in 64bit to support >4GB blobs.
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uint64_t maxBytesPerLeaf() const;
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uint64_t tryReadBytes(void *target, uint64_t offset, uint64_t count) const;
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void readBytes(void *target, uint64_t offset, uint64_t count) const;
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cpputils::Data readAllBytes() const;
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void writeBytes(const void *source, uint64_t offset, uint64_t count);
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void resizeNumBytes(uint64_t newNumBytes);
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uint32_t numNodes() const;
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uint32_t numLeaves() const;
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uint64_t numBytes() const;
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uint8_t depth() const;
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// only used by test cases
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uint32_t forceComputeNumLeaves() const;
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void flush() const;
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private:
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// This mutex must protect the tree structure, i.e. which nodes exist and how they're connected.
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// Also protects total number of bytes (i.e. number of leaves + size of last leaf).
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// It also protects the data in leaf nodes, because writing bytes might grow the blob and change the structure.
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mutable boost::shared_mutex _treeStructureMutex;
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datanodestore::DataNodeStore *_nodeStore;
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cpputils::unique_ref<datanodestore::DataNode> _rootNode;
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blockstore::BlockId _blockId; // BlockId is stored in a member variable, since _rootNode is nullptr while traversing, but we still want to be able to return the blockId.
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struct SizeCache final {
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uint32_t numLeaves;
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uint64_t numBytes;
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};
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mutable CachedValue<SizeCache> _sizeCache;
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cpputils::unique_ref<datanodestore::DataNode> releaseRootNode();
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friend class DataTreeStore;
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void _traverseLeavesByLeafIndices(uint32_t beginIndex, uint32_t endIndex, bool readOnlyTraversal,
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std::function<void (uint32_t index, bool isRightBorderLeaf, LeafHandle leaf)> onExistingLeaf,
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std::function<cpputils::Data (uint32_t index)> onCreateLeaf,
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std::function<void (datanodestore::DataInnerNode *node)> onBacktrackFromSubtree) const;
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void _traverseLeavesByByteIndices(uint64_t beginByte, uint64_t sizeBytes, bool readOnlyTraversal, std::function<void (uint64_t leafOffset, LeafHandle leaf, uint32_t begin, uint32_t count)> onExistingLeaf, std::function<cpputils::Data (uint64_t beginByte, uint32_t count)> onCreateLeaf) const;
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uint32_t _leavesPerFullChild(const datanodestore::DataInnerNode &root) const;
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SizeCache _getOrComputeSizeCache() const;
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SizeCache _computeSizeCache(const datanodestore::DataNode &node) const;
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uint64_t _tryReadBytes(void *target, uint64_t offset, uint64_t count) const;
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void _doReadBytes(void *target, uint64_t offset, uint64_t count) const;
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uint64_t _numBytes() const;
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DISALLOW_COPY_AND_ASSIGN(DataTree);
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};
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}
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}
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}
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#endif
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