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Make traversal exception safe

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This commit is contained in:
Sebastian Messmer 2019-01-06 10:25:50 -08:00
parent 8b1b685475
commit 6c006721a7
3 changed files with 19 additions and 22 deletions
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2
src/blobstore/implementations/onblocks/datatreestore/DataTree.cpp
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@ -108,7 +108,7 @@ void DataTree::_traverseLeaves(uint32_t beginIndex, uint32_t endIndex,
function<void (uint32_t index, bool isRightBorderLeaf, LeafHandle leaf)> onExistingLeaf,
function<Data (uint32_t index)> onCreateLeaf,
function<void (DataInnerNode *node)> onBacktrackFromSubtree) {
_rootNode = LeafTraverser(_nodeStore).traverseAndReturnRoot(std::move(_rootNode), beginIndex, endIndex, onExistingLeaf, onCreateLeaf, onBacktrackFromSubtree);
LeafTraverser(_nodeStore).traverseAndUpdateRoot(&_rootNode, beginIndex, endIndex, onExistingLeaf, onCreateLeaf, onBacktrackFromSubtree);
}
uint32_t DataTree::leavesPerFullChild(const DataInnerNode &root) const {

29
src/blobstore/implementations/onblocks/datatreestore/impl/LeafTraverser.cpp
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@ -24,11 +24,11 @@ namespace blobstore {
: _nodeStore(nodeStore) {
}
unique_ref<DataNode> LeafTraverser::traverseAndReturnRoot(unique_ref<DataNode> root, uint32_t beginIndex, uint32_t endIndex, function<void (uint32_t index, bool isRightBorderLeaf, LeafHandle leaf)> onExistingLeaf, function<Data (uint32_t index)> onCreateLeaf, function<void (DataInnerNode *node)> onBacktrackFromSubtree) {
return _traverseAndReturnRoot(std::move(root), beginIndex, endIndex, true, onExistingLeaf, onCreateLeaf, onBacktrackFromSubtree);
void LeafTraverser::traverseAndUpdateRoot(unique_ref<DataNode>* root, uint32_t beginIndex, uint32_t endIndex, function<void (uint32_t index, bool isRightBorderLeaf, LeafHandle leaf)> onExistingLeaf, function<Data (uint32_t index)> onCreateLeaf, function<void (DataInnerNode *node)> onBacktrackFromSubtree) {
_traverseAndUpdateRoot(root, beginIndex, endIndex, true, onExistingLeaf, onCreateLeaf, onBacktrackFromSubtree);
}
unique_ref<DataNode> LeafTraverser::_traverseAndReturnRoot(unique_ref<DataNode> root, uint32_t beginIndex, uint32_t endIndex, bool isLeftBorderOfTraversal, function<void (uint32_t index, bool isRightBorderLeaf, LeafHandle leaf)> onExistingLeaf, function<Data (uint32_t index)> onCreateLeaf, function<void (DataInnerNode *node)> onBacktrackFromSubtree) {
void LeafTraverser::_traverseAndUpdateRoot(unique_ref<DataNode>* root, uint32_t beginIndex, uint32_t endIndex, bool isLeftBorderOfTraversal, function<void (uint32_t index, bool isRightBorderLeaf, LeafHandle leaf)> onExistingLeaf, function<Data (uint32_t index)> onCreateLeaf, function<void (DataInnerNode *node)> onBacktrackFromSubtree) {
ASSERT(beginIndex <= endIndex, "Invalid parameters");
//TODO Test cases with numLeaves < / >= beginIndex, ideally test all configurations:
@ -36,11 +36,11 @@ namespace blobstore {
// beginIndex<numLeaves<endIndex, beginIndex=numLeaves<endIndex,
// numLeaves<beginIndex<endIndex, numLeaves<beginIndex=endIndex
uint32_t maxLeavesForDepth = _maxLeavesForTreeDepth(root->depth());
uint32_t maxLeavesForDepth = _maxLeavesForTreeDepth((*root)->depth());
bool increaseTreeDepth = endIndex > maxLeavesForDepth;
if (root->depth() == 0) {
DataLeafNode *leaf = dynamic_cast<DataLeafNode*>(root.get());
if ((*root)->depth() == 0) {
DataLeafNode *leaf = dynamic_cast<DataLeafNode*>(root->get());
ASSERT(leaf != nullptr, "Depth 0 has to be leaf node");
if (increaseTreeDepth && leaf->numBytes() != _nodeStore->layout().maxBytesPerLeaf()) {
@ -51,7 +51,7 @@ namespace blobstore {
onExistingLeaf(0, isRightBorderLeaf, LeafHandle(_nodeStore, leaf));
}
} else {
DataInnerNode *inner = dynamic_cast<DataInnerNode*>(root.get());
DataInnerNode *inner = dynamic_cast<DataInnerNode*>(root->get());
ASSERT(inner != nullptr, "Depth != 0 has to be leaf node");
_traverseExistingSubtree(inner, std::min(beginIndex, maxLeavesForDepth),
std::min(endIndex, maxLeavesForDepth), 0, isLeftBorderOfTraversal, !increaseTreeDepth,
@ -64,12 +64,12 @@ namespace blobstore {
// and only then increase the depth - this causes the tree to be in consistent shape (balanced) for longer.
if (increaseTreeDepth) {
// TODO Test cases that increase tree depth by 0, 1, 2, ... levels
auto newRoot = _increaseTreeDepth(std::move(root));
return _traverseAndReturnRoot(std::move(newRoot), std::max(beginIndex, maxLeavesForDepth), endIndex, false, onExistingLeaf, onCreateLeaf, onBacktrackFromSubtree);
*root = _increaseTreeDepth(std::move(*root));
_traverseAndUpdateRoot(root, std::max(beginIndex, maxLeavesForDepth), endIndex, false, onExistingLeaf, onCreateLeaf, onBacktrackFromSubtree);
} else {
// Once we're done growing the tree and done with the traversal, we might have to decrease tree depth,
// because the callbacks could have deleted nodes (this happens for example when shrinking the tree using a traversal).
return _whileRootHasOnlyOneChildReplaceRootWithItsChild(std::move(root));
_whileRootHasOnlyOneChildReplaceRootWithItsChild(root);
}
}
@ -218,15 +218,12 @@ namespace blobstore {
};
}
unique_ref<DataNode> LeafTraverser::_whileRootHasOnlyOneChildReplaceRootWithItsChild(unique_ref<DataNode> root) {
DataInnerNode *inner = dynamic_cast<DataInnerNode*>(root.get());
void LeafTraverser::_whileRootHasOnlyOneChildReplaceRootWithItsChild(unique_ref<DataNode>* root) {
DataInnerNode *inner = dynamic_cast<DataInnerNode*>(root->get());
if (inner != nullptr && inner->numChildren() == 1) {
auto newRoot = _whileRootHasOnlyOneChildRemoveRootReturnChild(inner->readChild(0).blockId());
auto result = _nodeStore->overwriteNodeWith(std::move(root), *newRoot);
*root = _nodeStore->overwriteNodeWith(std::move(*root), *newRoot);
_nodeStore->remove(std::move(newRoot));
return result;
} else {
return root;
}
}

10
src/blobstore/implementations/onblocks/datatreestore/impl/LeafTraverser.h
View File

@ -27,8 +27,8 @@ namespace blobstore {
public:
LeafTraverser(datanodestore::DataNodeStore *nodeStore);
cpputils::unique_ref<datanodestore::DataNode> traverseAndReturnRoot(
cpputils::unique_ref<datanodestore::DataNode> root, uint32_t beginIndex, uint32_t endIndex,
void traverseAndUpdateRoot(
cpputils::unique_ref<datanodestore::DataNode>* root, uint32_t beginIndex, uint32_t endIndex,
std::function<void (uint32_t index, bool isRightBorderLeaf, LeafHandle leaf)> onExistingLeaf,
std::function<cpputils::Data (uint32_t index)> onCreateLeaf,
std::function<void (datanodestore::DataInnerNode *node)> onBacktrackFromSubtree);
@ -36,8 +36,8 @@ namespace blobstore {
private:
datanodestore::DataNodeStore *_nodeStore;
cpputils::unique_ref<datanodestore::DataNode> _traverseAndReturnRoot(
cpputils::unique_ref<datanodestore::DataNode> root, uint32_t beginIndex, uint32_t endIndex, bool isLeftBorderOfTraversal,
void _traverseAndUpdateRoot(
cpputils::unique_ref<datanodestore::DataNode>* root, uint32_t beginIndex, uint32_t endIndex, bool isLeftBorderOfTraversal,
std::function<void (uint32_t index, bool isRightBorderLeaf, LeafHandle leaf)> onExistingLeaf,
std::function<cpputils::Data (uint32_t index)> onCreateLeaf,
std::function<void (datanodestore::DataInnerNode *node)> onBacktrackFromSubtree);
@ -55,7 +55,7 @@ namespace blobstore {
std::function<void (datanodestore::DataInnerNode *node)> onBacktrackFromSubtree);
uint32_t _maxLeavesForTreeDepth(uint8_t depth) const;
std::function<cpputils::Data (uint32_t index)> _createMaxSizeLeaf() const;
cpputils::unique_ref<datanodestore::DataNode> _whileRootHasOnlyOneChildReplaceRootWithItsChild(cpputils::unique_ref<datanodestore::DataNode> root);
void _whileRootHasOnlyOneChildReplaceRootWithItsChild(cpputils::unique_ref<datanodestore::DataNode>* root);
cpputils::unique_ref<datanodestore::DataNode> _whileRootHasOnlyOneChildRemoveRootReturnChild(const blockstore::BlockId &blockId);
DISALLOW_COPY_AND_ASSIGN(LeafTraverser);