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/*
* Copyright (C) 2019 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 specic language governing permissions and
* limitations under the License.
*/
#include "include/libfuse_jni/RedactionInfo.h"
using std::unique_ptr;
using std::vector;
namespace mediaprovider {
namespace fuse {
/**
* Merges any overlapping ranges into 1 range.
*
* Given ranges should be sorted, and they remain sorted.
*/
static void mergeOverlappingRedactionRanges(vector<RedactionRange>& ranges) {
int newRangesSize = ranges.size();
for (int i = 0; i < ranges.size() - 1; ++i) {
if (ranges[i].second >= ranges[i + 1].first) {
ranges[i + 1].first = ranges[i].first;
ranges[i + 1].second = std::max(ranges[i].second, ranges[i + 1].second);
// Invalidate the redundant range
ranges[i].first = LONG_MAX;
ranges[i].second = LONG_MAX;
newRangesSize--;
}
}
if (newRangesSize < ranges.size()) {
// Move invalid ranges to end of array
std::sort(ranges.begin(), ranges.end());
ranges.resize(newRangesSize);
}
}
/**
* Determine whether the read request overlaps with the redaction ranges
* defined by the given RedactionInfo.
*
* This function assumes redaction_ranges_ within RedactionInfo is sorted.
*/
bool RedactionInfo::hasOverlapWithReadRequest(size_t size, off64_t off) const {
if (!isRedactionNeeded() || off > redaction_ranges_.back().second ||
off + size < redaction_ranges_.front().first) {
return false;
}
return true;
}
/**
* Sets the redaction ranges in RedactionInfo, sort the ranges and merge
* overlapping ranges.
*/
void RedactionInfo::processRedactionRanges(int redaction_ranges_num,
const off64_t* redaction_ranges) {
redaction_ranges_.resize(redaction_ranges_num);
for (int i = 0; i < redaction_ranges_num; ++i) {
redaction_ranges_[i].first = static_cast<off64_t>(redaction_ranges[2 * i]);
redaction_ranges_[i].second = static_cast<off64_t>(redaction_ranges[2 * i + 1]);
}
std::sort(redaction_ranges_.begin(), redaction_ranges_.end());
mergeOverlappingRedactionRanges(redaction_ranges_);
}
int RedactionInfo::size() const {
return redaction_ranges_.size();
}
bool RedactionInfo::isRedactionNeeded() const {
return size() > 0;
}
RedactionInfo::RedactionInfo(int redaction_ranges_num, const off64_t* redaction_ranges) {
if (redaction_ranges == 0) return;
processRedactionRanges(redaction_ranges_num, redaction_ranges);
}
unique_ptr<vector<RedactionRange>> RedactionInfo::getOverlappingRedactionRanges(size_t size,
off64_t off) const {
if (hasOverlapWithReadRequest(size, off)) {
auto first_redaction = redaction_ranges_.end();
auto last_redaction = redaction_ranges_.end();
for (auto iter = redaction_ranges_.begin(); iter != redaction_ranges_.end(); ++iter) {
const RedactionRange& rr = *iter;
// Look for the first range that overlaps with the read request
if (first_redaction == redaction_ranges_.end() && off <= rr.second &&
off + size >= rr.first) {
first_redaction = iter;
} else if (first_redaction != redaction_ranges_.end() && off + size < rr.first) {
// Once we're in the read request range, we start checking if
// we're out of it so we can return the result to the caller
break;
}
last_redaction = iter;
}
if (first_redaction != redaction_ranges_.end()) {
return std::make_unique<vector<RedactionRange>>(first_redaction, last_redaction + 1);
}
}
return std::make_unique<vector<RedactionRange>>();
}
} // namespace fuse
} // namespace mediaprovider
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