Files
netris-cdc-file-transfer/data_store/data_store_reader.cc
Christian Schneider 4326e972ac Releasing the former Stadia file transfer tools
The tools allow efficient and fast synchronization of large directory
trees from a Windows workstation to a Linux target machine.

cdc_rsync* support efficient copy of files by using content-defined
chunking (CDC) to identify chunks within files that can be reused.

asset_stream_manager + cdc_fuse_fs support efficient streaming of a
local directory to a remote virtual file system based on FUSE. It also
employs CDC to identify and reuse unchanged data chunks.
2022-11-03 10:39:10 +01:00

99 lines
3.2 KiB
C++

// Copyright 2022 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "data_store/data_store_reader.h"
#include "absl/strings/str_format.h"
#include "common/status_macros.h"
#include "manifest/content_id.h"
namespace cdc_ft {
bool ChunkTransferList::ReadDone() const {
for (auto it = begin(); it != end(); ++it) {
if (it->size && !it->done) return false;
}
return true;
}
bool ChunkTransferList::PrefetchDone() const {
for (auto it = begin(); it != end(); ++it) {
if (!it->done) return false;
}
return true;
}
std::string ChunkTransferList::ToHexString(
std::function<bool(const ChunkTransferTask&)> filter) const {
std::string ids;
for (auto it = begin(); it != end(); ++it) {
if (filter && !filter(*it)) continue;
if (!ids.empty()) ids += ", ";
ids += ContentId::ToHexString(it->id);
}
return ids;
}
std::string ChunkTransferList::UndoneToHexString() const {
return ToHexString(
[](const ChunkTransferTask& chunk) { return !chunk.done; });
}
size_t DataStoreReader::PrefetchSize(size_t read_size) const {
return read_size;
}
absl::Status DataStoreReader::Get(ChunkTransferList* chunks) {
absl::StatusOr<uint64_t> bytes_read;
for (ChunkTransferTask& chunk : *chunks) {
// This default implementation skips prefetching tasks (chunk.size == 0).
if (chunk.done || !chunk.size) continue;
bytes_read = Get(chunk.id, chunk.data, chunk.offset, chunk.size);
if (bytes_read.ok()) {
if (*bytes_read != chunk.size) {
return MakeStatus(
"Corrupted chunk %s detected, expected to read %u bytes, got %u",
ContentId::ToHexString(chunk.id), chunk.size, *bytes_read);
}
chunk.done = true;
} else {
// Return any unexpected error.
if (!absl::IsNotFound(bytes_read.status())) return bytes_read.status();
}
}
return absl::OkStatus();
}
absl::Status DataStoreReader::GetProto(const ContentIdProto& content_id,
google::protobuf::Message* proto) {
Buffer chunk;
return GetProto(content_id, &chunk, proto);
}
absl::Status DataStoreReader::GetProto(const ContentIdProto& content_id,
Buffer* buf,
google::protobuf::Message* proto) {
// Fetch the referenced chunk.
RETURN_IF_ERROR(Get(content_id, buf));
// Parse the manifest proto from the chunk.
if (!proto->ParseFromArray(buf->data(), static_cast<int>(buf->size()))) {
return absl::InternalError(absl::StrFormat(
"Failed to parse %s from chunk '%s'", proto->GetTypeName(),
ContentId::ToHexString(content_id)));
}
return absl::OkStatus();
}
} // namespace cdc_ft