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93 lines
3.1 KiB
93 lines
3.1 KiB
4 months ago
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/*
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* Copyright (C) 2020 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 "SerializedLogChunk.h"
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#include <android-base/logging.h>
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#include "CompressionEngine.h"
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#include "SerializedFlushToState.h"
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SerializedLogChunk::~SerializedLogChunk() {
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CHECK_EQ(reader_ref_count_, 0U);
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}
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void SerializedLogChunk::FinishWriting() {
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writer_active_ = false;
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CHECK_EQ(compressed_log_.size(), 0U);
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CompressionEngine::GetInstance().Compress(contents_, write_offset_, compressed_log_);
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LOG(VERBOSE) << "Compressed Log, buffer max size: " << contents_.size()
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<< " size used: " << write_offset_
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<< " compressed size: " << compressed_log_.size();
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if (reader_ref_count_ == 0) {
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contents_.Resize(0);
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}
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}
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// TODO: Develop a better reference counting strategy to guard against the case where the writer is
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// much faster than the reader, and we needlessly compess / decompress the logs.
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void SerializedLogChunk::IncReaderRefCount() {
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if (++reader_ref_count_ != 1 || writer_active_) {
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return;
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}
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contents_.Resize(write_offset_);
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CompressionEngine::GetInstance().Decompress(compressed_log_, contents_);
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}
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void SerializedLogChunk::DecReaderRefCount() {
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CHECK_NE(reader_ref_count_, 0U);
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if (--reader_ref_count_ != 0) {
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return;
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}
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if (!writer_active_) {
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contents_.Resize(0);
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}
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}
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void SerializedLogChunk::AttachReader(SerializedFlushToState* reader) {
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readers_.emplace_back(reader);
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IncReaderRefCount();
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}
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void SerializedLogChunk::DetachReader(SerializedFlushToState* reader) {
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auto it = std::find(readers_.begin(), readers_.end(), reader);
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CHECK(readers_.end() != it);
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readers_.erase(it);
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DecReaderRefCount();
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}
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void SerializedLogChunk::NotifyReadersOfPrune(log_id_t log_id) {
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// Readers will call DetachReader() in their Prune() call, so we make a copy of the list first.
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auto readers = readers_;
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for (auto& reader : readers) {
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reader->Prune(log_id);
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}
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}
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bool SerializedLogChunk::CanLog(size_t len) {
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return write_offset_ + len <= contents_.size();
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}
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SerializedLogEntry* SerializedLogChunk::Log(uint64_t sequence, log_time realtime, uid_t uid,
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pid_t pid, pid_t tid, const char* msg, uint16_t len) {
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auto new_log_address = contents_.data() + write_offset_;
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auto* entry = new (new_log_address) SerializedLogEntry(uid, pid, tid, sequence, realtime, len);
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memcpy(entry->msg(), msg, len);
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write_offset_ += entry->total_len();
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highest_sequence_number_ = sequence;
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return entry;
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}
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