b3e163399a
This logic isn't generic, so it should not be in the generic LogReaderThread. Moreover, it's currently broken in essentially every case except when filtering by UID, because it runs as in the filter functions before the actual filtering by pid/etc takes place. For example, when filtering by pid, it's possible to get leading chatty messages. The newly added test was failing previously but is fixed by this change. It's fundamentally broken in the tail case. Take this example: 1: Normal message 2: Chatty message 3: Normal message 4: Normal message If you read that log buffer with a tail value of 3, there are three possible outcomes: 1) Messages #2-4, however this would include a leading chatty message, which is not allowed. 2) Messages #3-4, however this is only 2, not 3 messages. 3) Messages #1-4, however this is 4, more than the 3 requested messages. This code chooses 2) as the correct solution, in this case, we don't need to account for leading chatty messages when counting the total logs in the buffer. A test is added for this case as well. Test: new unit test Change-Id: Id02eb81a8e77390aba4f85aac659c6cab498dbcd
75 lines
2.2 KiB
C++
75 lines
2.2 KiB
C++
/*
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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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#pragma once
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#include <sys/types.h>
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#include <functional>
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#include <log/log.h>
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#include <log/log_read.h>
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#include "LogWriter.h"
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// A mask to represent which log buffers a reader is watching, values are (1 << LOG_ID_MAIN), etc.
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using LogMask = uint32_t;
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constexpr uint32_t kLogMaskAll = 0xFFFFFFFF;
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// State that a LogBuffer may want to persist across calls to FlushTo().
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class FlushToState {
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public:
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FlushToState(uint64_t start, LogMask log_mask) : start_(start), log_mask_(log_mask) {}
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virtual ~FlushToState() {}
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uint64_t start() const { return start_; }
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void set_start(uint64_t start) { start_ = start; }
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LogMask log_mask() const { return log_mask_; }
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private:
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uint64_t start_;
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LogMask log_mask_;
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};
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// Enum for the return values of the `filter` function passed to FlushTo().
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enum class FilterResult {
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kSkip,
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kStop,
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kWrite,
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};
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class LogBuffer {
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public:
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virtual ~LogBuffer() {}
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virtual void Init() = 0;
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virtual int Log(log_id_t log_id, log_time realtime, uid_t uid, pid_t pid, pid_t tid,
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const char* msg, uint16_t len) = 0;
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virtual std::unique_ptr<FlushToState> CreateFlushToState(uint64_t start, LogMask log_mask) = 0;
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virtual bool FlushTo(
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LogWriter* writer, FlushToState& state,
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const std::function<FilterResult(log_id_t log_id, pid_t pid, uint64_t sequence,
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log_time realtime)>& filter) = 0;
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virtual bool Clear(log_id_t id, uid_t uid) = 0;
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virtual unsigned long GetSize(log_id_t id) = 0;
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virtual int SetSize(log_id_t id, unsigned long size) = 0;
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virtual uint64_t sequence() const = 0;
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};
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