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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 "SerializedLogChunk.h"
#include <android-base/logging.h>
#include "CompressionEngine.h"
#include "SerializedFlushToState.h"
SerializedLogChunk::~SerializedLogChunk() {
CHECK_EQ(reader_ref_count_, 0U);
}
void SerializedLogChunk::FinishWriting() {
writer_active_ = false;
CHECK_EQ(compressed_log_.size(), 0U);
CompressionEngine::GetInstance().Compress(contents_, write_offset_, compressed_log_);
LOG(VERBOSE) << "Compressed Log, buffer max size: " << contents_.size()
<< " size used: " << write_offset_
<< " compressed size: " << compressed_log_.size();
if (reader_ref_count_ == 0) {
contents_.Resize(0);
}
}
// TODO: Develop a better reference counting strategy to guard against the case where the writer is
// much faster than the reader, and we needlessly compess / decompress the logs.
void SerializedLogChunk::IncReaderRefCount() {
if (++reader_ref_count_ != 1 || writer_active_) {
return;
}
contents_.Resize(write_offset_);
CompressionEngine::GetInstance().Decompress(compressed_log_, contents_);
}
void SerializedLogChunk::DecReaderRefCount() {
CHECK_NE(reader_ref_count_, 0U);
if (--reader_ref_count_ != 0) {
return;
}
if (!writer_active_) {
contents_.Resize(0);
}
}
void SerializedLogChunk::AttachReader(SerializedFlushToState* reader) {
readers_.emplace_back(reader);
IncReaderRefCount();
}
void SerializedLogChunk::DetachReader(SerializedFlushToState* reader) {
auto it = std::find(readers_.begin(), readers_.end(), reader);
CHECK(readers_.end() != it);
readers_.erase(it);
DecReaderRefCount();
}
void SerializedLogChunk::NotifyReadersOfPrune(log_id_t log_id) {
// Readers will call DetachReader() in their Prune() call, so we make a copy of the list first.
auto readers = readers_;
for (auto& reader : readers) {
reader->Prune(log_id);
}
}
bool SerializedLogChunk::CanLog(size_t len) {
return write_offset_ + len <= contents_.size();
}
SerializedLogEntry* SerializedLogChunk::Log(uint64_t sequence, log_time realtime, uid_t uid,
pid_t pid, pid_t tid, const char* msg, uint16_t len) {
auto new_log_address = contents_.data() + write_offset_;
auto* entry = new (new_log_address) SerializedLogEntry(uid, pid, tid, sequence, realtime, len);
memcpy(entry->msg(), msg, len);
write_offset_ += entry->total_len();
highest_sequence_number_ = sequence;
return entry;
}
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