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//
// Copyright (C) 2020 The Android Open Source Project
//
// 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 "update_engine/common/cow_operation_convert.h"
#include <base/logging.h>
#include "update_engine/payload_generator/extent_ranges.h"
#include "update_engine/payload_generator/extent_utils.h"
#include "update_engine/update_metadata.pb.h"
namespace chromeos_update_engine {
std::vector<CowOperation> ConvertToCowOperations(
const ::google::protobuf::RepeatedPtrField<
::chromeos_update_engine::InstallOperation>& operations,
const ::google::protobuf::RepeatedPtrField<CowMergeOperation>&
merge_operations) {
ExtentRanges merge_extents;
std::vector<CowOperation> converted;
ExtentRanges modified_extents;
// We want all CowCopy ops to be done first, before any COW_REPLACE happen.
// Therefore we add these ops in 2 separate loops. This is because during
// merge, a CowReplace might modify a block needed by CowCopy, so we always
// perform CowCopy first.
// This loop handles CowCopy blocks within SOURCE_COPY, and the next loop
// converts the leftover blocks to CowReplace?
for (const auto& merge_op : merge_operations) {
if (merge_op.type() != CowMergeOperation::COW_COPY) {
continue;
}
merge_extents.AddExtent(merge_op.dst_extent());
const auto& src_extent = merge_op.src_extent();
const auto& dst_extent = merge_op.dst_extent();
// Add blocks in reverse order, because snapused specifically prefers this
// ordering. Since we already eliminated all self-overlapping SOURCE_COPY
// during delta generation, this should be safe to do.
for (uint64_t i = src_extent.num_blocks(); i > 0; i--) {
auto src_block = src_extent.start_block() + i - 1;
auto dst_block = dst_extent.start_block() + i - 1;
converted.push_back({CowOperation::CowCopy, src_block, dst_block});
modified_extents.AddBlock(dst_block);
}
}
// COW_REPLACE are added after COW_COPY, because replace might modify blocks
// needed by COW_COPY. Please don't merge this loop with the previous one.
for (const auto& operation : operations) {
if (operation.type() != InstallOperation::SOURCE_COPY) {
continue;
}
const auto& src_extents = operation.src_extents();
const auto& dst_extents = operation.dst_extents();
BlockIterator it1{src_extents};
BlockIterator it2{dst_extents};
while (!it1.is_end() && !it2.is_end()) {
auto src_block = *it1;
auto dst_block = *it2;
if (!merge_extents.ContainsBlock(dst_block)) {
converted.push_back({CowOperation::CowReplace, src_block, dst_block});
}
++it1;
++it2;
}
}
return converted;
}
} // namespace chromeos_update_engine
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