//
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// Copyright (C) 2010 The Android Open Source Project
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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#include "update_engine/payload_generator/extent_ranges.h"
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#include <algorithm>
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#include <set>
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#include <utility>
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#include <vector>
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#include <base/logging.h>
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#include "update_engine/common/utils.h"
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#include "update_engine/payload_consumer/payload_constants.h"
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#include "update_engine/payload_generator/extent_utils.h"
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using std::set;
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using std::vector;
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namespace chromeos_update_engine {
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bool ExtentRanges::ExtentsOverlapOrTouch(const Extent& a, const Extent& b) {
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if (a.start_block() == b.start_block())
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return true;
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if (a.start_block() == kSparseHole || b.start_block() == kSparseHole)
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return false;
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if (a.start_block() < b.start_block()) {
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return a.start_block() + a.num_blocks() >= b.start_block();
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} else {
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return b.start_block() + b.num_blocks() >= a.start_block();
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}
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}
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bool ExtentRanges::ExtentsOverlap(const Extent& a, const Extent& b) {
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if (a.start_block() == b.start_block())
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return true;
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if (a.start_block() == kSparseHole || b.start_block() == kSparseHole)
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return false;
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if (a.start_block() < b.start_block()) {
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return a.start_block() + a.num_blocks() > b.start_block();
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} else {
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return b.start_block() + b.num_blocks() > a.start_block();
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}
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}
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void ExtentRanges::AddBlock(uint64_t block) {
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AddExtent(ExtentForRange(block, 1));
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}
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void ExtentRanges::SubtractBlock(uint64_t block) {
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SubtractExtent(ExtentForRange(block, 1));
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}
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namespace {
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Extent UnionOverlappingExtents(const Extent& first, const Extent& second) {
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CHECK_NE(kSparseHole, first.start_block());
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CHECK_NE(kSparseHole, second.start_block());
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uint64_t start = std::min(first.start_block(), second.start_block());
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uint64_t end = std::max(first.start_block() + first.num_blocks(),
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second.start_block() + second.num_blocks());
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return ExtentForRange(start, end - start);
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}
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} // namespace
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void ExtentRanges::AddExtent(Extent extent) {
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if (extent.start_block() == kSparseHole || extent.num_blocks() == 0)
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return;
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ExtentSet::iterator begin_del = extent_set_.end();
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ExtentSet::iterator end_del = extent_set_.end();
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uint64_t del_blocks = 0;
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for (ExtentSet::iterator it = extent_set_.begin(), e = extent_set_.end();
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it != e;
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++it) {
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if (ExtentsOverlapOrTouch(*it, extent)) {
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end_del = it;
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++end_del;
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del_blocks += it->num_blocks();
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if (begin_del == extent_set_.end())
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begin_del = it;
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extent = UnionOverlappingExtents(extent, *it);
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}
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}
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extent_set_.erase(begin_del, end_del);
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extent_set_.insert(extent);
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blocks_ -= del_blocks;
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blocks_ += extent.num_blocks();
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}
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namespace {
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// Returns base - subtractee (set subtraction).
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ExtentRanges::ExtentSet SubtractOverlappingExtents(const Extent& base,
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const Extent& subtractee) {
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ExtentRanges::ExtentSet ret;
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if (subtractee.start_block() > base.start_block()) {
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ret.insert(ExtentForRange(base.start_block(),
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subtractee.start_block() - base.start_block()));
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}
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uint64_t base_end = base.start_block() + base.num_blocks();
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uint64_t subtractee_end = subtractee.start_block() + subtractee.num_blocks();
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if (base_end > subtractee_end) {
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ret.insert(ExtentForRange(subtractee_end, base_end - subtractee_end));
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}
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return ret;
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}
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} // namespace
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void ExtentRanges::SubtractExtent(const Extent& extent) {
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if (extent.start_block() == kSparseHole || extent.num_blocks() == 0)
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return;
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ExtentSet::iterator begin_del = extent_set_.end();
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ExtentSet::iterator end_del = extent_set_.end();
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uint64_t del_blocks = 0;
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ExtentSet new_extents;
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for (ExtentSet::iterator it = extent_set_.begin(), e = extent_set_.end();
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it != e;
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++it) {
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if (!ExtentsOverlap(*it, extent))
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continue;
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if (begin_del == extent_set_.end())
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begin_del = it;
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end_del = it;
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++end_del;
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del_blocks += it->num_blocks();
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ExtentSet subtraction = SubtractOverlappingExtents(*it, extent);
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for (ExtentSet::iterator jt = subtraction.begin(), je = subtraction.end();
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jt != je;
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++jt) {
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new_extents.insert(*jt);
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del_blocks -= jt->num_blocks();
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}
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}
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extent_set_.erase(begin_del, end_del);
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extent_set_.insert(new_extents.begin(), new_extents.end());
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blocks_ -= del_blocks;
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}
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void ExtentRanges::AddRanges(const ExtentRanges& ranges) {
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for (ExtentSet::const_iterator it = ranges.extent_set_.begin(),
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e = ranges.extent_set_.end();
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it != e;
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++it) {
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AddExtent(*it);
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}
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}
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void ExtentRanges::SubtractRanges(const ExtentRanges& ranges) {
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for (ExtentSet::const_iterator it = ranges.extent_set_.begin(),
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e = ranges.extent_set_.end();
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it != e;
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++it) {
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SubtractExtent(*it);
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}
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}
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void ExtentRanges::AddExtents(const vector<Extent>& extents) {
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for (vector<Extent>::const_iterator it = extents.begin(), e = extents.end();
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it != e;
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++it) {
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AddExtent(*it);
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}
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}
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void ExtentRanges::SubtractExtents(const vector<Extent>& extents) {
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for (vector<Extent>::const_iterator it = extents.begin(), e = extents.end();
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it != e;
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++it) {
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SubtractExtent(*it);
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}
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}
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void ExtentRanges::AddRepeatedExtents(
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const ::google::protobuf::RepeatedPtrField<Extent>& exts) {
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for (int i = 0, e = exts.size(); i != e; ++i) {
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AddExtent(exts.Get(i));
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}
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}
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void ExtentRanges::SubtractRepeatedExtents(
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const ::google::protobuf::RepeatedPtrField<Extent>& exts) {
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for (int i = 0, e = exts.size(); i != e; ++i) {
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SubtractExtent(exts.Get(i));
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}
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}
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bool ExtentRanges::ContainsBlock(uint64_t block) const {
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auto lower = extent_set_.lower_bound(ExtentForRange(block, 1));
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// The block could be on the extent before the one in |lower|.
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if (lower != extent_set_.begin())
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lower--;
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// Any extent starting at block+1 or later is not interesting, so this is the
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// upper limit.
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auto upper = extent_set_.lower_bound(ExtentForRange(block + 1, 0));
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for (auto iter = lower; iter != upper; ++iter) {
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if (iter->start_block() <= block &&
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block < iter->start_block() + iter->num_blocks()) {
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return true;
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}
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}
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return false;
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}
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void ExtentRanges::Dump() const {
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LOG(INFO) << "ExtentRanges Dump. blocks: " << blocks_;
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for (ExtentSet::const_iterator it = extent_set_.begin(),
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e = extent_set_.end();
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it != e;
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++it) {
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LOG(INFO) << "{" << it->start_block() << ", " << it->num_blocks() << "}";
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}
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}
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Extent ExtentForRange(uint64_t start_block, uint64_t num_blocks) {
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Extent ret;
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ret.set_start_block(start_block);
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ret.set_num_blocks(num_blocks);
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return ret;
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}
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Extent ExtentForBytes(uint64_t block_size,
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uint64_t start_bytes,
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uint64_t size_bytes) {
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uint64_t start_block = start_bytes / block_size;
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uint64_t end_block = utils::DivRoundUp(start_bytes + size_bytes, block_size);
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return ExtentForRange(start_block, end_block - start_block);
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}
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vector<Extent> ExtentRanges::GetExtentsForBlockCount(uint64_t count) const {
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vector<Extent> out;
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if (count == 0)
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return out;
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uint64_t out_blocks = 0;
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CHECK(count <= blocks_);
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for (ExtentSet::const_iterator it = extent_set_.begin(),
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e = extent_set_.end();
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it != e;
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++it) {
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const uint64_t blocks_needed = count - out_blocks;
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const Extent& extent = *it;
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out.push_back(extent);
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out_blocks += extent.num_blocks();
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if (extent.num_blocks() < blocks_needed)
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continue;
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if (extent.num_blocks() == blocks_needed)
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break;
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// If we get here, we just added the last extent needed, but it's too big
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out_blocks -= extent.num_blocks();
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out_blocks += blocks_needed;
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out.back().set_num_blocks(blocks_needed);
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break;
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}
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CHECK(out_blocks == utils::BlocksInExtents(out));
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return out;
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}
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vector<Extent> FilterExtentRanges(const vector<Extent>& extents,
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const ExtentRanges& ranges) {
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vector<Extent> result;
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const ExtentRanges::ExtentSet& extent_set = ranges.extent_set();
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for (Extent extent : extents) {
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// The extents are sorted by the start_block. We want to iterate all the
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// Extents in the ExtentSet possibly overlapping the current |extent|. This
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// is achieved by looking from the extent whose start_block is *lower* than
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// the extent.start_block() up to the greatest extent whose start_block is
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// lower than extent.start_block() + extent.num_blocks().
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auto lower = extent_set.lower_bound(extent);
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// We need to decrement the lower_bound to look at the extent that could
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// overlap the beginning of the current |extent|.
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if (lower != extent_set.begin())
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lower--;
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auto upper = extent_set.lower_bound(
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ExtentForRange(extent.start_block() + extent.num_blocks(), 0));
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for (auto iter = lower; iter != upper; ++iter) {
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if (!ExtentRanges::ExtentsOverlap(extent, *iter))
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continue;
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if (iter->start_block() <= extent.start_block()) {
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// We need to cut blocks from the beginning of the |extent|.
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uint64_t cut_blocks =
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iter->start_block() + iter->num_blocks() - extent.start_block();
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if (cut_blocks >= extent.num_blocks()) {
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extent.set_num_blocks(0);
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break;
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}
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extent = ExtentForRange(extent.start_block() + cut_blocks,
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extent.num_blocks() - cut_blocks);
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} else {
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// We need to cut blocks on the middle of the extent, possible up to the
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// end of it.
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result.push_back(ExtentForRange(
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extent.start_block(), iter->start_block() - extent.start_block()));
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uint64_t new_start = iter->start_block() + iter->num_blocks();
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uint64_t old_end = extent.start_block() + extent.num_blocks();
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if (new_start >= old_end) {
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extent.set_num_blocks(0);
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break;
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}
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extent = ExtentForRange(new_start, old_end - new_start);
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}
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}
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if (extent.num_blocks() > 0)
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result.push_back(extent);
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}
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return result;
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}
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} // namespace chromeos_update_engine
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