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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.
*/
#pragma once
#include <sys/types.h>
#include <list>
#include <vector>
#include <android-base/logging.h>
#include "LogWriter.h"
#include "LogdLock.h"
#include "SerializedData.h"
#include "SerializedLogEntry.h"
class SerializedFlushToState;
class SerializedLogChunk {
public:
friend void VerifyChunks(const std::list<SerializedLogChunk>& expected,
const std::list<SerializedLogChunk>& chunks);
class LogEntryIterator {
public:
LogEntryIterator(SerializedLogChunk& chunk, int read_offset_)
: chunk_(chunk), read_offset_(read_offset_) {}
LogEntryIterator& operator++() {
read_offset_ += chunk_.log_entry(read_offset_)->total_len();
return *this;
}
bool operator!=(const LogEntryIterator& other) const {
return read_offset_ != other.read_offset_;
}
const SerializedLogEntry& operator*() const { return *chunk_.log_entry(read_offset_); }
private:
SerializedLogChunk& chunk_;
int read_offset_;
};
explicit SerializedLogChunk(size_t size) : contents_(size) {}
SerializedLogChunk(SerializedLogChunk&& other) noexcept = default;
~SerializedLogChunk();
void FinishWriting();
void IncReaderRefCount();
void DecReaderRefCount();
void AttachReader(SerializedFlushToState* reader);
void DetachReader(SerializedFlushToState* reader);
void NotifyReadersOfPrune(log_id_t log_id) REQUIRES(logd_lock);
bool CanLog(size_t len);
SerializedLogEntry* Log(uint64_t sequence, log_time realtime, uid_t uid, pid_t pid, pid_t tid,
const char* msg, uint16_t len);
// If this buffer has been compressed, we only consider its compressed size when accounting for
// memory consumption for pruning. This is since the uncompressed log is only by used by
// readers, and thus not a representation of how much these logs cost to keep in memory.
size_t PruneSize() const {
return sizeof(*this) + (compressed_log_.size() ?: contents_.size());
}
const SerializedLogEntry* log_entry(int offset) const {
CHECK(writer_active_ || reader_ref_count_ > 0);
return reinterpret_cast<const SerializedLogEntry*>(data() + offset);
}
const uint8_t* data() const { return contents_.data(); }
int write_offset() const { return write_offset_; }
uint64_t highest_sequence_number() const { return highest_sequence_number_; }
LogEntryIterator begin() { return LogEntryIterator(*this, 0); }
LogEntryIterator end() { return LogEntryIterator(*this, write_offset_); }
// Exposed for testing
uint32_t reader_ref_count() const { return reader_ref_count_; }
private:
// The decompressed contents of this log buffer. Deallocated when the ref_count reaches 0 and
// writer_active_ is false.
SerializedData contents_;
int write_offset_ = 0;
uint32_t reader_ref_count_ = 0;
bool writer_active_ = true;
uint64_t highest_sequence_number_ = 1;
SerializedData compressed_log_;
std::vector<SerializedFlushToState*> readers_;
};
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