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Introduce Blob::readAll() and introduce a size cache so the blob size doesn't have to be queried so often

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This commit is contained in:
Sebastian Messmer 2015-10-05 03:45:00 +02:00
parent 6e436b7a59
commit ca9f3fe2e6
3 changed files with 34 additions and 7 deletions
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35
implementations/onblocks/BlobOnBlocks.cpp
View File

@ -8,6 +8,7 @@
using std::function;
using cpputils::unique_ref;
using cpputils::Data;
using blobstore::onblocks::datanodestore::DataLeafNode;
using blobstore::onblocks::datanodestore::DataNodeLayout;
using blockstore::Key;
@ -18,18 +19,22 @@ namespace onblocks {
using parallelaccessdatatreestore::DataTreeRef;
BlobOnBlocks::BlobOnBlocks(unique_ref<DataTreeRef> datatree)
: _datatree(std::move(datatree)) {
: _datatree(std::move(datatree)), _sizeCache(boost::none) {
}
BlobOnBlocks::~BlobOnBlocks() {
}
uint64_t BlobOnBlocks::size() const {
return _datatree->numStoredBytes();
if (_sizeCache == boost::none) {
_sizeCache = _datatree->numStoredBytes();
}
return *_sizeCache;
}
void BlobOnBlocks::resize(uint64_t numBytes) {
_datatree->resizeNumBytes(numBytes);
_sizeCache = numBytes;
}
void BlobOnBlocks::traverseLeaves(uint64_t beginByte, uint64_t sizeBytes, function<void (uint64_t, DataLeafNode *leaf, uint32_t, uint32_t)> func) const {
@ -47,10 +52,22 @@ void BlobOnBlocks::traverseLeaves(uint64_t beginByte, uint64_t sizeBytes, functi
}
func(indexOfFirstLeafByte, leaf, dataBegin, dataEnd-dataBegin);
});
if (writingOutside) {
//ASSERT(_datatree->numStoredBytes() == endByte, "Writing didn't grow by the correct number of bytes");
_sizeCache = endByte;
}
}
Data BlobOnBlocks::readAll() const {
//TODO Querying size is inefficient. Is this possible without numStoredBytes()?
uint64_t count = size();
Data result(count);
_read(result.data(), 0, count);
return result;
}
void BlobOnBlocks::read(void *target, uint64_t offset, uint64_t count) const {
ASSERT(offset <= _datatree->numStoredBytes() && offset + count <= size(), "BlobOnBlocks::read() read outside blob. Use BlobOnBlocks::tryRead() if this should be allowed.");
ASSERT(offset <= size() && offset + count <= size(), "BlobOnBlocks::read() read outside blob. Use BlobOnBlocks::tryRead() if this should be allowed.");
uint64_t read = tryRead(target, offset, count);
ASSERT(read == count, "BlobOnBlocks::read() couldn't read all requested bytes. Use BlobOnBlocks::tryRead() if this should be allowed.");
}
@ -58,13 +75,17 @@ void BlobOnBlocks::read(void *target, uint64_t offset, uint64_t count) const {
uint64_t BlobOnBlocks::tryRead(void *target, uint64_t offset, uint64_t count) const {
//TODO Quite inefficient to call size() here, because that has to traverse the tree
uint64_t realCount = std::max(UINT64_C(0), std::min(count, size()-offset));
traverseLeaves(offset, realCount, [target, offset] (uint64_t indexOfFirstLeafByte, const DataLeafNode *leaf, uint32_t leafDataOffset, uint32_t leafDataSize) {
//TODO Simplify formula, make it easier to understand
leaf->read((uint8_t*)target + indexOfFirstLeafByte - offset + leafDataOffset, leafDataOffset, leafDataSize);
});
_read(target, offset, realCount);
return realCount;
}
void BlobOnBlocks::_read(void *target, uint64_t offset, uint64_t count) const {
traverseLeaves(offset, count, [target, offset] (uint64_t indexOfFirstLeafByte, const DataLeafNode *leaf, uint32_t leafDataOffset, uint32_t leafDataSize) {
//TODO Simplify formula, make it easier to understand
leaf->read((uint8_t*)target + indexOfFirstLeafByte - offset + leafDataOffset, leafDataOffset, leafDataSize);
});
}
void BlobOnBlocks::write(const void *source, uint64_t offset, uint64_t count) {
traverseLeaves(offset, count, [source, offset] (uint64_t indexOfFirstLeafByte, DataLeafNode *leaf, uint32_t leafDataOffset, uint32_t leafDataSize) {
//TODO Simplify formula, make it easier to understand

4
implementations/onblocks/BlobOnBlocks.h
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@ -5,6 +5,7 @@
#include "../../interface/Blob.h"
#include <memory>
#include <boost/optional.hpp>
namespace blobstore {
namespace onblocks {
@ -25,6 +26,7 @@ public:
uint64_t size() const override;
void resize(uint64_t numBytes) override;
cpputils::Data readAll() const override;
void read(void *target, uint64_t offset, uint64_t size) const override;
uint64_t tryRead(void *target, uint64_t offset, uint64_t size) const override;
void write(const void *source, uint64_t offset, uint64_t size) override;
@ -35,9 +37,11 @@ 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, datanodestore::DataLeafNode *, uint32_t, uint32_t)>) const;
cpputils::unique_ref<parallelaccessdatatreestore::DataTreeRef> _datatree;
mutable boost::optional<uint64_t> _sizeCache;
};
}

2
interface/Blob.h
View File

@ -5,6 +5,7 @@
#include <cstring>
#include <cstdint>
#include <messmer/blockstore/utils/Key.h>
#include <messmer/cpp-utils/data/Data.h>
namespace blobstore {
@ -18,6 +19,7 @@ public:
virtual uint64_t size() const = 0;
virtual void resize(uint64_t numBytes) = 0;
virtual cpputils::Data readAll() const = 0;
virtual void read(void *target, uint64_t offset, uint64_t size) const = 0;
virtual uint64_t tryRead(void *target, uint64_t offset, uint64_t size) const = 0;
virtual void write(const void *source, uint64_t offset, uint64_t size) = 0;