Simplify code a bit and add assertions

src/blobstore/implementations/onblocks/BlobOnBlocks.cpp

@@ -37,7 +37,7 @@ void BlobOnBlocks::resize(uint64_t numBytes) {
   _sizeCache = numBytes;
 }
 
-void BlobOnBlocks::traverseLeaves(uint64_t beginByte, uint64_t sizeBytes, function<void (uint64_t leafOffset, DataLeafNode *leaf, uint32_t begin, uint32_t count)> onExistingLeaf, function<Data (uint64_t leafOffset, uint32_t begin, uint32_t count)> onCreateLeaf) const {
+void BlobOnBlocks::traverseLeaves(uint64_t beginByte, uint64_t sizeBytes, function<void (uint64_t leafOffset, DataLeafNode *leaf, uint32_t begin, uint32_t count)> onExistingLeaf, function<Data (uint64_t beginByte, uint32_t count)> onCreateLeaf) const {
   uint64_t endByte = beginByte + sizeBytes;
   uint64_t maxBytesPerLeaf = _datatree->maxBytesPerLeaf();
   uint32_t firstLeaf = beginByte / maxBytesPerLeaf;
@@ -46,6 +46,7 @@ void BlobOnBlocks::traverseLeaves(uint64_t beginByte, uint64_t sizeBytes, functi
   auto _onExistingLeaf = [&onExistingLeaf, beginByte, endByte, endLeaf, maxBytesPerLeaf, &blobIsGrowingFromThisTraversal] (uint32_t leafIndex, DataLeafNode *leaf) {
       uint64_t indexOfFirstLeafByte = leafIndex * maxBytesPerLeaf;
       ASSERT(endByte > indexOfFirstLeafByte, "Traversal went too far right");
+      ASSERT(leafIndex == endLeaf-1 || leaf->numBytes() == maxBytesPerLeaf, "All leafes but the rightmost one have to have maximal size");
       uint32_t dataBegin = utils::maxZeroSubtraction(beginByte, indexOfFirstLeafByte);
       uint32_t dataEnd = std::min(maxBytesPerLeaf, endByte - indexOfFirstLeafByte);
       if (leafIndex == endLeaf-1 && leaf->numBytes() < dataEnd) {
@@ -55,13 +56,16 @@ void BlobOnBlocks::traverseLeaves(uint64_t beginByte, uint64_t sizeBytes, functi
       }
       onExistingLeaf(indexOfFirstLeafByte, leaf, dataBegin, dataEnd-dataBegin);
   };
-  auto _onCreateLeaf = [&onCreateLeaf, maxBytesPerLeaf, beginByte, endByte, &blobIsGrowingFromThisTraversal] (uint32_t leafIndex) -> Data {
+  auto _onCreateLeaf = [&onCreateLeaf, maxBytesPerLeaf, beginByte, firstLeaf, endByte, endLeaf, &blobIsGrowingFromThisTraversal] (uint32_t leafIndex) -> Data {
       blobIsGrowingFromThisTraversal = true;
       uint64_t indexOfFirstLeafByte = leafIndex * maxBytesPerLeaf;
       ASSERT(endByte > indexOfFirstLeafByte, "Traversal went too far right");
       uint32_t dataBegin = utils::maxZeroSubtraction(beginByte, indexOfFirstLeafByte);
       uint32_t dataEnd = std::min(maxBytesPerLeaf, endByte - indexOfFirstLeafByte);
-      Data data = onCreateLeaf(indexOfFirstLeafByte, dataBegin, dataEnd-dataBegin);
+      ASSERT(leafIndex == firstLeaf || dataBegin == 0, "Only the leftmost leaf can have a gap on the left.");
+      ASSERT(leafIndex == endLeaf-1 || dataEnd == maxBytesPerLeaf, "Only the rightmost leaf can have a gap on the right");
+      Data data = onCreateLeaf(indexOfFirstLeafByte + dataBegin, dataEnd-dataBegin);
+      ASSERT(data.size() == dataEnd-dataBegin, "Returned leaf data with wrong size");
       // If this leaf is created but only partly in the traversed region (i.e. dataBegin > leafBegin), we have to fill the data before the traversed region with zeroes.
       if (dataBegin != 0) {
         Data actualData(dataBegin + data.size());
@@ -69,7 +73,6 @@ void BlobOnBlocks::traverseLeaves(uint64_t beginByte, uint64_t sizeBytes, functi
         std::memcpy(actualData.dataOffset(dataBegin), data.data(), data.size());
         data = std::move(actualData);
       }
-      ASSERT(data.size() == dataEnd, "Returned leaf data with wrong size");
       return data;
   };
   _datatree->traverseLeaves(firstLeaf, endLeaf, _onExistingLeaf, _onCreateLeaf);
@@ -106,7 +109,7 @@ void BlobOnBlocks::_read(void *target, uint64_t offset, uint64_t count) const {
       //TODO Simplify formula, make it easier to understand
       leaf->read((uint8_t*)target + indexOfFirstLeafByte - offset + leafDataOffset, leafDataOffset, leafDataSize);
   };
-  auto onCreateLeaf = [] (uint64_t /*indexOfFirstLeafByte*/, uint32_t /*begin*/, uint32_t /*count*/) -> Data {
+  auto onCreateLeaf = [] (uint64_t /*beginByte*/, uint32_t /*count*/) -> Data {
       ASSERT(false, "Reading shouldn't create new leaves.");
   };
   traverseLeaves(offset, count, onExistingLeaf, onCreateLeaf);
@@ -117,10 +120,10 @@ void BlobOnBlocks::write(const void *source, uint64_t offset, uint64_t count) {
       //TODO Simplify formula, make it easier to understand
       leaf->write((uint8_t*)source + indexOfFirstLeafByte - offset + leafDataOffset, leafDataOffset, leafDataSize);
   };
-  auto onCreateLeaf = [source, offset] (uint64_t indexOfFirstLeafByte, uint32_t leafDataOffset, uint32_t count) -> Data {
+  auto onCreateLeaf = [source, offset] (uint64_t beginByte, uint32_t count) -> Data {
       Data result(count);
       //TODO Simplify formula, make it easier to understand
-      std::memcpy(result.data(), (uint8_t*)source + indexOfFirstLeafByte - offset + leafDataOffset, count);
+      std::memcpy(result.data(), (uint8_t*)source + beginByte - offset, count);
       return result;
   };
   traverseLeaves(offset, count, onExistingLeaf, onCreateLeaf);

src/blobstore/implementations/onblocks/BlobOnBlocks.h

@@ -38,7 +38,7 @@ public:
 private:
 
   void _read(void *target, uint64_t offset, uint64_t count) const;
-  void traverseLeaves(uint64_t offsetBytes, uint64_t sizeBytes, std::function<void (uint64_t leafOffset, datanodestore::DataLeafNode *leaf, uint32_t begin, uint32_t count)> onExistingLeaf, std::function<cpputils::Data (uint64_t leafOffset, uint32_t begin, uint32_t count)> onCreateLeaf) const;
+  void traverseLeaves(uint64_t offsetBytes, uint64_t sizeBytes, std::function<void (uint64_t leafOffset, datanodestore::DataLeafNode *leaf, uint32_t begin, uint32_t count)> onExistingLeaf, std::function<cpputils::Data (uint64_t beginByte, uint32_t count)> onCreateLeaf) const;
 
   cpputils::unique_ref<parallelaccessdatatreestore::DataTreeRef> _datatree;
   mutable boost::optional<uint64_t> _sizeCache;