libcryfs/implementations/ondisk/OnDiskBlock.cpp

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#include <cstring>
#include <fstream>
#include <boost/filesystem.hpp>
#include "OnDiskBlock.h"
#include "OnDiskBlockStore.h"
#include "../../utils/FileDoesntExistException.h"
#include <messmer/cpp-utils/assert/assert.h>
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using std::istream;
using std::ostream;
using std::ifstream;
using std::ofstream;
using std::ios;
using cpputils::Data;
using cpputils::make_unique_ref;
using cpputils::unique_ref;
using boost::optional;
using boost::none;
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namespace bf = boost::filesystem;
namespace blockstore {
namespace ondisk {
OnDiskBlock::OnDiskBlock(const Key &key, const bf::path &filepath, Data data)
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: Block(key), _filepath(filepath), _data(std::move(data)), _dataChanged(false), _mutex() {
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}
OnDiskBlock::~OnDiskBlock() {
flush();
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}
const void *OnDiskBlock::data() const {
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return _data.data();
}
void OnDiskBlock::write(const void *source, uint64_t offset, uint64_t size) {
ASSERT(offset <= _data.size() && offset + size <= _data.size(), "Write outside of valid area"); //Also check offset < _data->size() because of possible overflow in the addition
std::memcpy((uint8_t*)_data.data()+offset, source, size);
_dataChanged = true;
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}
size_t OnDiskBlock::size() const {
return _data.size();
}
optional<unique_ref<OnDiskBlock>> OnDiskBlock::LoadFromDisk(const bf::path &rootdir, const Key &key) {
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auto filepath = rootdir / key.ToString();
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try {
//If it isn't a file, Data::LoadFromFile() would usually also crash. We still need this extra check
//upfront, because Data::LoadFromFile() doesn't crash if we give it the path of a directory
//instead the path of a file.
//TODO Data::LoadFromFile now returns boost::optional. Do we then still need this?
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if(!bf::is_regular_file(filepath)) {
return none;
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}
boost::optional<Data> data = Data::LoadFromFile(filepath);
if (!data) {
return none;
}
return make_unique_ref<OnDiskBlock>(key, filepath, std::move(*data));
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} catch (const FileDoesntExistException &e) {
return none;
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}
}
optional<unique_ref<OnDiskBlock>> OnDiskBlock::CreateOnDisk(const bf::path &rootdir, const Key &key, Data data) {
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auto filepath = rootdir / key.ToString();
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if (bf::exists(filepath)) {
return none;
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}
auto block = make_unique_ref<OnDiskBlock>(key, filepath, std::move(data));
block->_storeToDisk();
return std::move(block);
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}
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void OnDiskBlock::RemoveFromDisk(const bf::path &rootdir, const Key &key) {
auto filepath = rootdir / key.ToString();
ASSERT(bf::is_regular_file(filepath), "Block not found on disk");
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bf::remove(filepath);
}
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void OnDiskBlock::_fillDataWithZeroes() {
_data.FillWithZeroes();
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_dataChanged = true;
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}
void OnDiskBlock::_storeToDisk() const {
_data.StoreToFile(_filepath);
}
void OnDiskBlock::flush() {
std::unique_lock<std::mutex> lock(_mutex);
if (_dataChanged) {
_storeToDisk();
_dataChanged = false;
}
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}
}
}