Introduce Data::copy() and test case for it, refactor FakeBlobStore using Data::copy()

src/blockstore/implementations/testfake/FakeBlockStore.cpp

@@ -15,8 +15,7 @@ FakeBlockStore::FakeBlockStore()
  : _blocks(), _used_dataregions_for_blocks() {}
 
 unique_ptr<Block> FakeBlockStore::create(const Key &key, size_t size) {
-  string key_string = key.AsString();
-  auto insert_result = _blocks.emplace(key_string, size);
+  auto insert_result = _blocks.emplace(key.AsString(), size);
   insert_result.first->second.FillWithZeroes();
 
   if (!insert_result.second) {
@@ -24,24 +23,25 @@ unique_ptr<Block> FakeBlockStore::create(const Key &key, size_t size) {
   }
 
   //Return a copy of the stored data
-  _used_dataregions_for_blocks.push_back(make_shared<Data>(size));
-  std::memcpy(_used_dataregions_for_blocks.back()->data(), insert_result.first->second.data(), size);
-  return make_unique<FakeBlock>(this, key_string, _used_dataregions_for_blocks.back());
+  return load(key);
 }
 
 unique_ptr<Block> FakeBlockStore::load(const Key &key) {
   //Return a copy of the stored data
   string key_string = key.AsString();
   try {
-    const Data &data = _blocks.at(key_string);
-    _used_dataregions_for_blocks.push_back(make_shared<Data>(data.size()));
-    std::memcpy(_used_dataregions_for_blocks.back()->data(), data.data(), data.size());
-    return make_unique<FakeBlock>(this, key_string, _used_dataregions_for_blocks.back());
+    return makeFakeBlockFromData(key_string, _blocks.at(key_string));
   } catch (const std::out_of_range &e) {
     return nullptr;
   }
 }
 
+unique_ptr<Block> FakeBlockStore::makeFakeBlockFromData(const std::string &key, const Data &data) {
+  auto newdata = make_shared<Data>(data.copy());
+  _used_dataregions_for_blocks.push_back(newdata);
+  return make_unique<FakeBlock>(this, key, newdata);
+}
+
 void FakeBlockStore::updateData(const std::string &key, const Data &data) {
   Data &stored_data = _blocks.at(key);
   assert(data.size() == stored_data.size());

src/blockstore/implementations/testfake/FakeBlockStore.h

@@ -46,6 +46,8 @@ private:
   //We want to avoid this for the reasons mentioned above (overflow data).
   std::vector<std::shared_ptr<Data>> _used_dataregions_for_blocks;
 
+  std::unique_ptr<Block> makeFakeBlockFromData(const std::string &key, const Data &data);
+
   DISALLOW_COPY_AND_ASSIGN(FakeBlockStore);
 };
 

src/blockstore/utils/Data.cpp

@@ -34,6 +34,12 @@ Data::~Data() {
   _data = nullptr;
 }
 
+Data Data::copy() const {
+  Data copy(_size);
+  std::memcpy(copy._data, _data, _size);
+  return copy;
+}
+
 void *Data::data() {
   return const_cast<void*>(const_cast<const Data*>(this)->data());
 }

src/blockstore/utils/Data.h

@@ -17,6 +17,8 @@ public:
   Data(Data &&rhs); // move constructor
   virtual ~Data();
 
+  Data copy() const;
+
   void *data();
   const void *data() const;
 

src/test/blockstore/utils/DataTest.cpp

@@ -125,6 +125,15 @@ TEST_P(DataTestWithSizeParam, StoreAndLoad) {
   EXPECT_DATA_CORRECT(loaded_data);
 }
 
+TEST_P(DataTestWithSizeParam, Copy) {
+  Data data(GetParam());
+  FillData(&data);
+
+  Data copy = data.copy();
+
+  EXPECT_DATA_CORRECT(copy);
+}
+
 TEST_F(DataTest, InitializeWithZeroes) {
   Data data(10*1024);
   data.FillWithZeroes();