| /* |
| * 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 "LogWriter.h" |
| #include "SerializedData.h" |
| #include "SerializedLogEntry.h" |
| |
| class SerializedLogChunk { |
| public: |
| explicit SerializedLogChunk(size_t size) : contents_(size) {} |
| SerializedLogChunk(SerializedLogChunk&& other) noexcept = default; |
| ~SerializedLogChunk(); |
| |
| void Compress(); |
| void IncReaderRefCount(); |
| void DecReaderRefCount(); |
| |
| // Must have no readers referencing this. Return true if there are no logs left in this chunk. |
| bool ClearUidLogs(uid_t uid, log_id_t log_id, LogStatistics* stats); |
| |
| 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()); |
| } |
| |
| void FinishWriting() { |
| writer_active_ = false; |
| Compress(); |
| if (reader_ref_count_ == 0) { |
| contents_.Resize(0); |
| } |
| } |
| |
| const SerializedLogEntry* log_entry(int offset) const { |
| 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_; } |
| |
| // 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_; |
| }; |